User talk:Chjoaygame/archive 3

Problem
I seem to have a recurrent problem with a certain editor. I am hoping that perhaps Editor Materialscientist might see it as within the remit of his wideranging good works to help? Or perhaps Editor Dirac66 might find it in his area? As I see it, my problem is that the editor in question sees himself as exempt from the usual custom of responding on, or taking account of, talk pages. Often I don't respond to his edits, on the principle of not feeding the trolls. But I suppose that may not be enough. Would you very kindly consider looking here, here, and here?Chjoaygame (talk) 22:49, 24 October 2015 (UTC)
 * The point at issue seems to be whether to specify in the intro that transfer of matter is excluded. When teaching physical chemistry my examples of adiabatic processes have always been in closed systems, but I will confess to never having considered whether this restriction is necessary - you may have noticed that my interests are broader but shallower than yours. So I will just say that this seems to be a substantive disagreement between two serious editors, and should be settled by finding an appropriate source or two. Can you find sources which say explicitly that adiabatic excludes matter transfer?
 * Also since the usual definition of adiabatic is just no heat, perhaps the no matter transfer condition can be introduced in the Description section (as it is now), and doesn't actually need to be in the intro. But even there a source would help. Dirac66 (talk) 02:26, 25 October 2015 (UTC)


 * Thank you for this. A main problem is that my friend doesn't engage on the talk page. A second problem is the one you indicate: mostly texts leave it immediately implicit that the adiabatic enclosure excludes matter transfer. The latter has been made explicit only in previous parts of the chapter, and is not repeated immediately at the place of definition of adiabaticity. When they get to open systems, usually they don't go back and rethink the definition of adiabaticity and say explicitly that it hasn't changed. It seems perhaps they regard that as too obvious to be stated again, or perhaps they just forget about it.


 * The restriction to exclude matter transfer is necessary. According to László Tisza "(adiabatic partitions inhibit the transfer of heat and mass)" . I would say that this is an immediately explicit statement of the point in question, made in perhaps the most systematic and reliable of sources. Sources as immediately explicit as this are not many. Buchdahl writes: "Let a system $K$ in equilibrium be contained entirely within an enclosure which need not be rigid but shall be supposed to be impermeable to matter. Then it is known from experience that it may be possible to disturb the equilibrium of $K$ only by mechanical means. When this is the case, the enclosure is said to be adiabatic." And: "Two systems are or are not adiabatically isolated from one another according as any interaction between them must be purely mechanical or not." This is not as immediately explicit as Tisza's statement.


 * I think it fair to observe that there are vast masses of implicit source material to indicate that adiabatic processes are always without matter transfer. There are reams of accounts of such processes. It would be misleading to leave the reader uninformed of this important though negative fact that is abundantly evident in a survey of the sources.


 * An adiabatic wall passes neither heat nor matter. With Born an exception, texts are not very forthcoming on the following. A system can have several walls, for example one adiabatic and another that can pass matter. But if matter transfer occurs in a process, then it is not adiabatic. Having both kinds of wall, the system has one of its walls adiabatic, but is not adiabatically isolated.


 * My friend says in his edit summary that he is referring to a "control-mass" mode of description, which means that he is not suggesting that an adiabatic process can include matter transfer. He refers just to "simplicity". What he sees as simplicity of expression I see as unnecessary ambiguity. You say that this seems to be a substantive disagreement. I think the disagreement is over presentation, not material factuality. I am also concerned about talk-page engagement.


 * Perhaps the next move is for me just to cite Tisza on the talk page, as well as in the article as you suggest, which I will try.Chjoaygame (talk) 08:21, 25 October 2015 (UTC)

improved French vocabulary
From reading , on page 234, I learnt an addition to my limited French vocabulary: 'astucieux'.Chjoaygame (talk) 03:25, 5 November 2015 (UTC)

ArbCom elections are now open!
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ArbCom elections are now open!
Hi, You appear to be eligible to vote in the current Arbitration Committee election. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to enact binding solutions for disputes between editors, primarily related to serious behavioural issues that the community has been unable to resolve. This includes the ability to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate, you are welcome to review the candidates' statements and submit your choices on the voting page. For the Election committee, MediaWiki message delivery (talk) 14:07, 24 November 2015 (UTC)

rescued by the Cavalry
I have just been rescued by the Cavalry, in the form of Editor Kingsindian. Many, many thanks to him for that.Chjoaygame (talk) 13:03, 30 November 2015 (UTC)

brd
Thank you, Editor Kingsindian for your very helpful contributions in this matter. Very often I do indeed follow the plan that you propose. But I have had some experiences that lead me, in some circumstances, to try variations on it. I am not sure that the variations are better or worse on different occasions. Sometimes it can be hard to get consensus. Best I say no more. Howsoever, your presence is very beneficial, it seems.Chjoaygame (talk) 13:47, 1 December 2015 (UTC)
 * I agree that WP:BRD can come across as hostile. I usually consider whether the other editor is relatively experienced or not. Actually, my practice usually is to do both simultaneously: revert and simultaneously open a discussion on the talk page. Arguing through edit summaries often creates conflict. See edits here, and here for examples. Kingsindian &#9821;&#9818; 13:55, 1 December 2015 (UTC)
 * Good Lord!! I can only repeat, your presence in this case is very beneficial, it seems.Chjoaygame (talk) 14:06, 1 December 2015 (UTC)

enough references supplied?
Please, Editor Chetvorno, would you very kindly be willing to look at Wave function collapse to see if I have supplied enough references?Chjoaygame (talk) 12:32, 4 December 2015 (UTC)

Kinetic theory
I'm curious about this: what exactly do you think "bots" are going to be doing over the next day or two? --R'n'B (call me Russ) 14:31, 23 December 2015 (UTC)
 * I have no idea. I just saw a notice that seemed me a request to leave things until after 23 December. I guessed someone had a reason to post that notice, and I thought I would support it.Chjoaygame (talk) 15:19, 23 December 2015 (UTC)

Dubious change of quote in Laws of thermodynamics
Hi. Do you have access to Guggenheim's Thermodynamics, 7th (1985) edition? If so, could you look at | this edit? Either the original editor or the latest editor has drastically changed what is supposed to be a direct quote, but I don't have the source to check who is right and who is wrong.

Also in either case, it would be good to add the page on which the quote appears. Dirac66 (talk) 23:15, 7 January 2016 (UTC)


 * Guggenheim's 1985 7th edition is a paperback reprint of the 1967 5th hardback, I think exactly reproduced. He died in 1966.


 * Though called a law by Maxwell, it was not initially assigned a number as a 'law of thermodynamics'. For example here. I don't recall for sure, and don't right now intend to check, but I think the A, B, C thing came from Planck, perhaps in 1897. I have an idea that when Fowler first used the numbering "zeroth", in the 1930's, in a book review of another book, he was just joking. But people love numbers!Chjoaygame (talk) 02:45, 8 January 2016 (UTC)

It is a typo
This just my opinion https://en.wikipedia.org/wiki/Quantum_mechanics You change my edit from "it's" back to "its" it's spelled with a ' --RedExplosives 15:27, 7 January 2016 (UTC)


 * In traditional English grammar, one says for example "his coming home was a joy for his family", not 'he coming home', nor 'him coming home'. The present participle is being used as a noun, not a verb. The 'his' and 'its' are possessive pronoun adjectives, not subjects nor objects of a verb. Your edit changed 'its' to 'it'.Chjoaygame (talk) 17:01, 7 January 2016 (UTC)

H atom: 2 meanings of adiabatic confused?
Hello. Could you look at Hydrogen atom and see if the word adiabatically is used correctly? The article now describes the hypothetical radiation of the electron in the pre-Bohr model as adiabatic. This seems odd as radiation is one mode of heat transfer along with conduction and convection. I looked at the source document by Olsen and McDonald, which refers to the adiabatic approximation, which is an alternate sense of the word adiabatic meaning quasi-static. Would you agree that the two senses of the word have been confused here and that the word should be omitted here? or perhaps be replaced by continuously? Dirac66 (talk) 19:04, 24 January 2016 (UTC)


 * Yes, I agree. Radiation is one of the modes of heat transfer.
 * In quantum mechanics the word is, as you say, used to mean 'very slowly and continuously, without heat transfer'; this means primarily change in the Hamiltonian, not primarily in the state of the system. In the passage you link to, the word refers primarily to change in the system without change in the Hamiltonian. I would say that is not normal usage, and could fairly be said to be wrong. Your suggestion of omission or use of 'continuous' seems right to me for this purpose in this context.Chjoaygame (talk) 19:53, 24 January 2016 (UTC)


 * OK, thanks. I had not thought to distinguish changes in Hamiltonian vs. changes in system. I have now changed the word to continuously. Dirac66 (talk) 20:29, 24 January 2016 (UTC)

definitions
I suggest you use the definitions in quantum state instead of experiments of thought. By "pure" is not meant "pure with respect to an observable" (whatever that means). There is not a trace of mixed states (as defined in the referenced article) in this article, and I consider the topic being off. YohanN7 (talk) 08:08, 7 February 2015 (UTC)


 * "Whatever that means." Feynman : "The answer is this: If the atoms are in a definite state with respect to $S$, they are not in the same state with respect to $T$—a $+S$ state is not also a $+T$ state. There is, however, a certain amplitude to find the atom in a $+T$ state—or a $0T$ state or a $−T$ state."[Feynman's format of —]Chjoaygame (talk) 03:04, 5 November 2015 (UTC)


 * A more general definition would be that measurement of (observable) $S$ with certainty would yield a certain value $s$. Mathematically, the state is an eigenstate of (the Hermitian operator) $S$. (Using the same symbol for observable quantity and corresponding operator is standard.) I don't mind using the terminology "state pure with respect to observable" as long as we define it and don't confuse it with "pure state", which is defined elsewhere in Wikipedia. YohanN7 (talk) 11:10, 5 November 2015 (UTC)


 * Thank you for your reply. I think it would be valuable to actually put an explicit version of that 'elsewhere' definition right here, or very much better, in your own words, for clarity of comparison, if you have time. I am asking not for a mathematical abstract expression, such as that of David J. Griffiths, who says he intends not to tell what quantum mechanics means, but rather to tell "how to do it"; "shut up and calculate", to quote Mermin. I am asking for a physical expression, like Feynman's. Wikipedia is not a reliable source.Chjoaygame (talk) 14:18, 5 November 2015 (UTC)


 * What do you want a physical expression for? "Pure state" or "Pure state with respect to observable"? If you are looking for "pure state" as opposed to "mixed state", then I'd suggest you go to the literature if you don't trust Wikipedia. I'm not suggesting Wikipedia as a reference for the article, but this is a talk page you know. I can only say that a superposition of eigenstates (more than one) of an observable is not a mixed state, but rather a pure state. But it is not a pure state with respect to the observable in question (as I am thinking about it here in this discussion). It may, however, be a pure state with respect to another observable. This is what Feynman alludes to. His $S$ and $T$ do not commute, hence if pure w r t $S$, then it is "mixed w r t $T$" (but not a mixed state). YohanN7 (talk) 12:19, 16 November 2015 (UTC)


 * Thank you for this reply. I value your care in this.


 * I was looking for a physical definition of a pure state. I have spent some effort on the literature, looking for a physical definition, but I find only mathematical ones, if you don't count 'pure with respect to a specified observable' as 'pure'. For definiteness, also I may refer to Wikipedia. There I am led to the article Quantum state, which is mathematical, not physical.


 * You advise me to "use the definitions in the article quantum state instead of experiments of thought". As I read this advice, it is to use mathematical definitions, not physical ones. My interest is in physics. Mathematics is useful for expression of physical ideas, but mathematics is not physics. I think physical ideas need expression in experimental terms as well as in mathematical terms. Without the experimental terms, they are undefined physically. I think experiments of thought are often near-enough to experimental expressions. With no experimental expression, we are not talking physics.


 * You write that "... a superposition of eigenstates (more than one) of an observable ... may, however, be a pure state with respect to another observable."


 * I agree. But I would go further and say that for a state to be pure, it must have an observable with respect to which it is pure. I am saying that a every pure state is pure with respect to some observable. Evidently you think I am mistaken in that?


 * There may be a problem here about the word 'ensemble'. It might have different meanings, depending on whether it was used in a physical or a probabilistic sense. In my view, a probability usually refers to an ensemble in a virtual sense used by probability theorists. Each single particle in an occasion of experiment has probabilities associated with it. Usually the probabilities are found in experiment by repeated, on occasion after occasion of experiment, practically identical preparations of single particles. By 'practically identical', I mean that definite identical practical steps are taken to prepare, on occasion after occasion of experiment, single particles. If there remain untaken further practical steps, by which the repeatedly prepared single particles could be further purified, then they are in a mixed state. If all possible further practical steps of purification have been taken, then the single particles are each in the same pure state. The repeatedly, on occasion after occasion of experiment, prepared single particles, constitute a probability theorist's virtual ensemble. A single occasion of preparation of a single particle does not provide experimental data for the determination of the relevant probabilities. In fact we cannot ensure that the practically identical particles are ultimately identical, whatever that might mean. I understand 'practically identical' in this sense to refer to single particles.


 * The single particles so prepared have not yet been observed. For observation, more is needed. In general, that 'more' is as follows. The single particles are passed, one by one, through some sorting process, and then detected by an array of particle detectors lying in the several output channels. The sorting process may be trivial, not actually doing anything. For a pure state, there is a definite sorting process, embodied in a definite physical device, symbolically designated by a definite linear operator, such that only one detector, of the several in the array, actually detects particles.


 * This is my idea of a physical definition of a pure state.


 * As I read you, the just-above story is, in your view, wrong. As I read you, you have not yet here proposed a physical definition of a pure state. Instead you advise me to be content with a mathematical one.Chjoaygame (talk) 22:00, 16 November 2015 (UTC)


 * Let us continue this discussion on either your or my talk page. You are welcome at my place.
 * I have not read the just-above story (I will, but not now). I can't see how you can argue with definitions. Definitions are there to establish terminology. You can't complain because you think the English word "pure" in "pure state" (through the definition) is misused in some linguistic or physical sense. You wrote,
 * I agree. But I would go further and say that for a state to be pure, it must have an observable with respect to which it is pure. I am saying that a every pure state is pure with respect to some observable. Evidently you think I am mistaken in that?.
 * You may be mistaken in that, depending on what you want. Mathematically you are right, because you can construct a Hermitian operator = observable with the state in question as an eigenvector. But its eigenvalues will in general have little to do with physically measurable quantities, which is what I guess you are after, in which case you are wrong.
 * Here is one attempt at definition of "pure state": Every vector in Hilbert space represent a pure state. (Mixed states are described not by state vectors, but by density matrices.) YohanN7 (talk) 10:11, 17 November 2015 (UTC)


 * Thank you for this. Following your suggestion, I will reply on my talk page.Chjoaygame (talk) 10:44, 17 November 2015 (UTC)

Have you checked out Landau & Lifshitz vol 3? Follow the link and you'll find an online copy. The relevant section should be "Density matrix" (or something like that), L&L are more physical than most, but don't rely on this book for the terminology (because it is old in its usage of terminology). YohanN7 (talk) 12:24, 17 November 2015 (UTC)


 * Thank you for this. It's time for me to sleep, so right now I won't chase up L&L. I will later. I have been writing something which I will shortly copy here from an edit conflict page.Chjoaygame (talk) 13:04, 17 November 2015 (UTC)


 * Interesting and helpful. Thank you.


 * On page 37 of the 4th edition, Dirac writes

The question now presents itself—Can every observable be measured? The answer theoretically is yes. In practice it may be very awkward, or perhaps even beyond the ingenuity of the experimenter, to devise an apparatus which could measure some particular observable, but the theory always allows one to imagine that the measurement can be made.


 * and on page 39

It is often very difficult to decide mathematically whether a particular real dynamical variable satisfies the condition for being an observable or not, because the whole problem of finding eigenvalues and eigenvectors is in general very difficult. However, we may have good reason on experimental grounds for believing that the dynamical variable can be measured and then we may reasonably assume that it is an observable even though the mathematical proof is missing. This is a thing we shall frequently do during the course of development of the theory, e.g. we shall assume the energy of any dynamical system to be always an observable, even though it is beyond the power of present-day mathematical analysis to prove it so except in simple cases.


 * What is that to me? It may take some talk to answer that.


 * Going to your answer above. I don't think of quantum observation as measurement. Though they call it that, I think they thereby abuse language. For me it is just observation, made by use of some sorting device with a detector in each of its output channels. In general (with obvious exceptions) an observation on a particle in a pure state is probabilistic, the probability being partly determined by the particle and partly by the random microstate of the sorting device. Not measurement in the ordinary sense, I think. Better and safer just to call it observation.


 * I need to defend myself when you say "You can't complain because you think the English word "pure" in "pure state" (through the definition) is misused in some linguistic or physical sense." I am not there complaining trivially, about the use or misuse of the ordinary English word. Rather, I am distinguishing a physical from a mathematical definition. And I think a physicist is entitled to ask for a physical definition. That means a definition in terms of experiment, and is far from a mere linguistic triviality. The above quotes from Dirac indicate that the experimenter's ingenuity might be insufficient. I say that if the experimenter can't make a sorting device that has an output channel that issues the proposed pure state, then that pure state will be hard or practically impossible to study experimentally. I am not sure right now, but I reserve a right to have my doubts about its standing as an interesting physical state.


 * You offer "Here is one attempt at definition of "pure state": Every vector in Hilbert space represents a pure state.".


 * I think it fair that I say this is a mathematical definition with no hint of physical meaning. Of course, I am not saying it is untrue. Also, of course, it is standard fare, found in every text. I think a physical definition must be that it is pure with respect to some properly constituted sorting device. I might say quite a lot more, but I think I have said enough for now.Chjoaygame (talk) 13:11, 17 November 2015 (UTC)


 * First off, I retract my comment that the terminology in L&L should be taken with a pinch of salt. It is spot on in the modern sense of terminological use, see footnote on p. 39. Then, Dirac's quotes are of course very relevant to the discussion. You will not be disappointed when you read L&L. You will find a reasonable physical definition of a pure state (early on p.40), in the spirit of Dirac, though they don't call it a definition, but rather a characterization. I'll not spoil your reading pleasure, except for this; pure states can be prepared ( in principle (added by me)), whereas mixed states cannot ( even in principle (also added by me, OR! - so block me) This was written with a context in mind, and isn't generally true. Cheers! YohanN7 (talk) 15:05, 17 November 2015 (UTC)


 * Backed up by Dirac and L&L, you can surely find a satisfactory physical definition of "pure state" and "mixed state" (by definition state not being a pure state) to go into quantum state and elsewhere. As for "pure state with respect to observable" as we have used it on the talk page doesn't really need a reference as long as it is specified what is meant for local (article) usage. It would simply be "eigenstate of particular observable". Feynman can of course be referenced for a similar usage, though he omitted "w r t observable" in his discussion (which was in a given context). YohanN7 (talk) 15:17, 17 November 2015 (UTC)

for definiteness
For definiteness, from L&L p. 39

For a state having a wave function there is always a complete set of measuring processes such that they lead with certainty to definite results (mathematically, this means that $Ψ$ is an eigenfunction of some operator).

and

† States having a wave function are sometimes called "pure" states, as distinct from "mixed" states, which are described by a density matrix.

I think it would not commit the crime of synthesis to write: For a state having a wave function, that is to say, for a pure state, there is always a complete set of measuring processes such that they lead with certainty to definite results (mathematically, this means that $Ψ$ is an eigenfunction of some operator).

I failed to find the word 'character' on page 40.

Dirac's Principles of Quantum Mechanics changed in some respects as it passed through its four editions, of 1930, 1935, 1947, and 1958.

In Dirac's 4th edition, its first chapter, in its first four sections, does not use mathematical symbols. His first chapter introduces mathematical symbols in its fifth and sixth sections.

I think in agreement with L&L, Dirac defines a state in various ways in various editions:

first edition, 1930
We must first generalize the meaning of a 'state' so that it can apply to any atomic system. Corresponding to the case of the photon, which we say is in a given state of polarization when it has been passed through suitable polarizing apparatus, we say that any atomic system is in a given state when it has been prepared in a given way, which may be repeated arbitrarily at will. The method of preparation may then be taken as the specification of the state.

The case of greatest interest of the compatibility of two observations is when they both refer to the same instant of time. The compatibility condition is now that if either is made a very short time before the other, the probability of any given result being obtained with the second shall be the same as if the first had not been made.

It is often convenient to count two or more compatible observations, particularly when they are simultaneous, as a single observation, the result of such an observation being expressible by two or more numbers. We shall frequently have to consider the greatest possible number of independent compatible simultaneous observations being made on a system and shall, for brevity, call such a set of observations a maximum observation. When a maximum observation is made on a system, its subsequent state is completely determined by the result of the observation and is independent of its previous state. This may be considered as an axiom, or as a more precise definition of a state.

The state of a system after a maximum observation has been made on it is such that there exists a maximum observation (namely, an immediate repetition of the maximum observation already made) which, when made on the system in this state, will for a certainty lead to one particular result (namely, the previous result over again). Any state can be specified only as the state ensuing after a given maximum observation has been made for which a given result was obtained, or in some equivalent way. We can therefore draw the conclusion that for any state there must exist one maximum observation which will for a certainty lead to one particular result, and conversely, if we consider any possible result of a maximum observation, there must exist a state of the system for which this result for the observation will be obtained with certainty.

second edition, 1935
A state of motion is completely specified when one is given that it is associated with a certain beam.

Corresponding to the description that we had in the case of the polarization, we must now describe the photon as going partly into each of the two components into which the incident beam is split. The photon is then, as we may say, in a state of motion given by the superposition of the two states of motion associated with the two components. We are thus led to a generalization of the term 'state of motion' applied to a photon. For a photon to be in a definite state of motion it need not be associated with one single beam of light, but may be associated with two or more beams of light which are the components into which the original one beam has been split.

I think there is a problem with Dirac's choice of the word 'partly'. It inadvertently suggests division of the photon into parts. A better word would be 'jointly'. This word 'jointly' suggests a more abstract link than does 'partly', and the intended link is indeed more abstract.

third edition, 1947
We know that each of them [photons in a beam] is located somewhere in the region of space through which the beam is passing, and has a momentum in the direction of the beam of magnitude given in terms of the frequency of the beam by Einstein's photo-electric law—momentum = frequency multiplied by a universal constant. When we have such information about the location and momentum of a photon, we shall say that it is in a definite translational state.

A state of a system may be defined as an undisturbed motion that is restricted by as many conditions or data as are theoretically possible without mutual interference or contradiction. In practice, the conditions could be imposed by a suitable preparation of the system, consisting perhaps of passing it through various kinds of sorting apparatus, such as slits and polarimeters, the system being undisturbed after preparation.

This definition passes intact from the 3rd to the 4th edition.

fourth edition, 1958
A state of a system may be defined as an undisturbed motion that is restricted by as many conditions or data as are theoretically possible without mutual interference or contradiction. In practice, the conditions could be imposed by a suitable preparation of the system, consisting perhaps of passing it through various kinds of sorting apparatus, such as slits and polarimeters, the system being undisturbed after preparation.

Bibliography for references

 * Dirac, P.A.M. (1930). The Principles of Quantum Mechanics, 1st edition, Oxford University Press, Oxford UK.
 * Dirac, P.A.M. (1935). The Principles of Quantum Mechanics, 2nd edition, Oxford University Press, Oxford UK.
 * Dirac, P.A.M. (1947). The Principles of Quantum Mechanics, 3rd edition, Oxford University Press, Oxford UK.
 * Dirac, P.A.M. (1958). The Principles of Quantum Mechanics, 4th edition, Oxford University Press, Oxford UK.

mixed state
You write "mixed states cannot [be prepared] ( even in principle )".

I think it depends what you mean by 'prepare'.

Roughly speaking, a vapour-containing oven with a hole in its wall emits a beam of atoms in a mixed state. Roughly speaking, Nature habitually delivers mixed states. One can influence which mixed state, for example, by changing the temperature of the oven. It would be hard in practice to prepare a beam that was in exactly some fully specified mixed state.

I think this will do for now.Chjoaygame (talk) 22:43, 17 November 2015 (UTC)


 * You are absolutely correct about my writings. I made a blunder, was in a hurry (library closing, my own computer is dead, later tried to make a quantum leap back in time to reedit - failed). It was written in the context of the footnote on p. 39. I'll strike that out above. YohanN7 (talk) 09:42, 18 November 2015 (UTC)


 * I read the first few paragraphs of L&L for bedtime reading. I can strongly recommend those paragraphs. They establish their terminology, and are fairly precise about what they mean by measurement. In particular, a measurement does not involve observers or experimentalists. It does however involve an apparatus. An apparatus is an object that to some desired degree obeys the laws of classical physics. (Between the lines, I read into that that nature measures itself on occasion) Further, terms such as physical quantity, observable, eigenstate, eigenvalue and operator are introduced directly from physical principles (primarily, particles do not follow paths) and the idea that a wave function provides the (classically incomplete) description. Rather ingenious. I think it is is important to get this right in order to make a definite formulation. YohanN7 (talk) 09:42, 18 November 2015 (UTC)
 * But I believe that this statement isn't generally true;
 * Roughly speaking, a vapour-containing oven with a hole in its wall emits a beam of atoms in a mixed state.
 * If you lower the intensity to one atom at-a-time, these atoms are decidedly in a pure state (wave packages). You might speculate about single atoms in a high-intensity beam being in a mixed state if there is significant interaction between the atoms. Then some of the conditions described in L&L apply, because we would be looking at a subsystem. But it is still not clean cut. The system as a whole can hardly qualify as closed.


 * I'd also say that nature does not habitually deliver mixed states when you consider small systems, like a definite isolated collection of particles. Mixed states in those cases only appear when you consider a subsystem. This is exactly the way L&L defines it. I'd guess that in the typical setup in accelerator experiments, the intensities of the beams are low enough that particles in the beams do not interact with other particles in the same beam. YohanN7 (talk) 10:17, 18 November 2015 (UTC)


 * Thank you for these interesting thoughts. I will copy parts and interlineate.

In particular, a measurement does not involve observers or experimentalists. It does however involve an apparatus. An apparatus is an object that to some desired degree obeys the laws of classical physics. (Between the lines, I read into that that nature measures itself on occasion).


 * Interesting. It is a dreadful pity that Bohr thought he was so clever that he could singlehandedly re-invent metaphysics, and then complain that ordinary professional metaphysicians were not interested in his works of revolutionary genius. Nevertheless, he did make some important and valuable points. The drivel that is sometimes (e.g. Wigner) talked about observers and whatnot evidently has made you rightly cautious in using such ideas.


 * True, L&L do not talk about observers or experimentalists. With careful respect to your caution, I think it is unrealistic to avoid them. They set up, operate, and read the apparatus and report the readings. There is good literature support for this. So it is ok to talk about them, taking them as implicit in the L&L account, though not giving them magical status.


 * Apparatus has two macroscopic components. The particles pass through a sorting device, and then pass into a detector. Either sorter or detector can be included unpaired in suitable contexts. Bohr called these macroscopic devices 'classical', but of course they are really governed by quantum mechanics. What matters is that they are macroscopic, and count particles.


 * The sorting device is such as a diffracting crystal or a Stern-Gerlach magnet. Passage through it is reversible. That is why the theory is symmetrical between bras and kets, as stated by Dirac, and why the designating operator is required to be Hermitian. The detector has a collective element that amplifies a single particle arrival into a macroscopic change, for example a silver iodide crystal that can be triggered to decompose and release metallic silver, or a photoelectric tube. Detection is irreversible. The experimenter does not wait for 10100 years to let the silver and iodine undergo a Poincaré recurrence back into a silver iodide crystal.


 * I think it a conceptual error to suggest that nature measures itself. The word 'measure' is abused in the quantum mechanical literature, but the abuse should not extend to saying that nature measures itself. If you think that is happening, I think you should find other words than 'measure' to express your thoughts.

Further, terms such as physical quantity, observable, eigenstate, eigenvalue and operator are introduced directly from physical principles (primarily, particles do not follow paths) and the idea that a wave function provides the (classically incomplete) description. Rather ingenious. I think it is is important to get this right in order to make a definite formulation.


 * I reserve my reply on this.

But I believe that this statement isn't generally true;
 * Roughly speaking, a vapour-containing oven with a hole in its wall emits a beam of atoms in a mixed state. If you lower the intensity to one atom at-a-time, these atoms are decidedly in a pure state (wave packages). You might speculate about single atoms in a high-intensity beam being in a mixed state if there is significant interaction between the atoms. Then some of the conditions described in L&L apply, because we would be looking at a subsystem. But it is still not clean cut. The system as a whole can hardly qualify as closed.


 * With respect. Quantum experiments measure probabilities. They do so by counting events in repeated occasions of preparation and observation of single quantum systems. One single occasion of preparation and detection is not adequate to count as a useful experiment; it cannot reveal the state. Many occasions of preparation and detection of single particles are needed. To decide if a state is pure or mixed, many single particles must be prepared and detected, one at a time. An adequate experiment is needed. With respect, lowering the intensity is useful to make sure that the particles are not interacting with one another, and is a good thing to do. But a mixed state is not one in which the particles of the beam interact. It is one in which successive non-interacting particles pass into and are detected in several different output channels of the sorting apparatus. A pure state is one in which they all pass into, and are detected in, one and the same output channel.

I'd also say that nature does not habitually deliver mixed states when you consider small systems, like a definite isolated collection of particles. Mixed states in those cases only appear when you consider a subsystem. This is exactly the way L&L defines it. I'd guess that in the typical setup in accelerator experiments, the intensities of the beams are low enough that particles in the beams do not interact with other particles in the same beam.


 * With respect, the L&L formulation is rather sophisticated. With respect, I think you are reading things that are not really there. A definite isolated collection of particles is still a quantum mechanical system. Whether it is in a mixed or pure state is found by observing repeated preparations of it, not by considering a one-off single preparation and detection of it. Yes, in general, in accelerator experiments, the particles of the beam can often usefully be regarded as non-interacting.


 * Perhaps enough for now.Chjoaygame (talk) 14:18, 18 November 2015 (UTC)


 * I am actually not sure you interpret "pure state" and "mixed state" the same way I do. Yes, quantum experiments measure probabilities. Probabilities are certainly involved in all pure states not being eigenfunctions of the observable measured. Measure theese probabilities (count number of particles in each channel), and you pin down the wave function describing the individual non-interacting particles that are presumably prepared the same way.
 * But a mixed state is not one in which the particles of the beam interact. It is one in which successive non-interacting particles pass into and are detected in several different output channels of the sorting apparatus. A pure state is one in which they all pass into, and are detected in, one and the same output channel.
 * No. You perhaps confuse "pure state" with what we have called "pure state with respect to particular observable", i.e. an eigenfunction of the corresponding operator.

---
 * To make it as clear as I can: A particle in a state
 * $$\Psi(r, s_z) = \psi(r)\left(\frac{1}{\sqrt{2}}\left|\uparrow\right\rangle + \frac{1}{\sqrt{2}}\left|\downarrow\right\rangle\right)$$
 * (spin up/down w r t $z$-axis) is in a pure state, even though a measurement of the spin $z$-projection can give the result of either "spin up" or "spin down". If you let a beam of such (assumed to be non-interacting) particles pass a Stern-Gerlach apparatus, you'll definitely not detect all particles in a single output channel. About half will go "up", the rest will go "down". Yet, the entering particles are in a pure state.
 * Question: Do you agree with this last paragraph? It is vitally important for further discussion that you let me know, preferably with a short answer conveying "yes" or "no" without quotes, experiments of thought or anything else. The reason is that I thought we had gotten at least somewhere. Your last post indicates that we have not. YohanN7 (talk) 15:36, 18 November 2015 (UTC)


 * Thank you for this. You are putting a gun at my head. At this stage of our discussion, your seem completely confident that I am wrong and you are right. I can only trust you will discuss first and shoot later.


 * (At the risk of creating a diversion, I will add another comment here. About your sentence "If you lower the intensity to one atom at-a-time, these atoms are decidedly in a pure state (wave packages). This sentence comes from very naughty thinking. It assumes you can look at the atoms one at a time regardless of the macroscopic experimental setting. Very much a no-no for quantum phenomena. The state is determined by the mode of preparation or by the mode of final sorting and detection, esentially macroscopic factors. The state is not affected by the intensity, as long as it is low enough to avoid inter-particle interaction. If it is not low enough, one is looking not at a one-particle system, but instead at a many-particle system, a different ball-game.)Chjoaygame (talk) 21:15, 18 November 2015 (UTC)


 * (Another diversion, or rather going back over some ground already partly discussed: "I'd also say that nature does not habitually deliver mixed states when you consider small systems, like a definite isolated collection of particles. Mixed states in those cases only appear when you consider a subsystem. This is exactly the way L&L defines it." L&L define the density matrix in a particular way, as an average for a subsystem of a containing closed system (isolated system). For the present one may read that as referring to an atom (the system, coordinates $x$) emitted from an oven (the containing closed system, coordinates $(x, q)$). While the atom is in the oven it interacts with the rest of the contents of the oven and its walls (coordinates $q$). When the atom leaves the oven and enters the beam, it no longer is close enough to the oven and walls to interact with them. It is still entangled with them. Its density operator is found by averaging over the $q$, in effect forgetting about them, forgetting the entanglement that results from the past interactions in the oven. As I see it, "Nature" has her way in the oven, in the sense that we have very little control over or detailed knowledge of what goes on in the oven. She delivers the atoms, one by one, into the beam. That is the description of how they are "prepared". "Nature" is here delivering the atoms, one by one, in a mixed state. The reason why the state is mixed is that "Nature" does not, in general, employ a complete set of sorting devices to purify the state: she just delivers the atoms, raw, one by one, through a hole in a wall of the oven.)Chjoaygame (talk) 01:43, 19 November 2015 (UTC)


 * Back to the main line of discussion: Mea culpa. My above statement of the difference between pure and mixed states is, as you note, obviously defective. But it is remediable. It is an example of a statement of probability made without full and explicit associated statement of the hypotheses on which the probability is based; a serious crime about which I endlessly pontificate.


 * (Later-added remark: To be explicit, my faulty sentence, to which you rightly object, was "A pure state is one in which they all pass into, and are detected in, one and the same output channel." It lacked the crucially necessary proviso 'provided the sorting device is properly chosen, noting that such a proper choice is necessarily possible for a pure state.'. This remark pretty well short-circuits the following ones.)21:15, 18 November 2015 (UTC)


 * The negligently omitted but utterly necessary statement of presupposed hypotheses is as follows. The observations referred to in my statement are made by passing the prepared particles immediately to a single sorting device. No intermediate adventures for the particles. For a mixed state, every choice of the single sorting device sends the particles into several output channels. For a pure state, if the single sorting device is other than one of a kind that was amongst those that were used in the preparation, to select the particles, it will send the particles into several output channels. But if the sorting device is of a kind that was amongst those used to prepare the particles, then all the particles will go into one and the same output channel. Moreover, that output channel will be the one that exactly matches the relevant output channel that selected the beam in the preparation. Again, I was negligent not to have said this from the start.


 * In a nutshell, a state is pure only if there exists a non-trivial sorting device that, placed immediately in the path of the freshly prepared beam, sends all the particles into one and the same output channel. More, there is a set of sorting devices that has this property. They are just of the kinds that that prepared the particles. Dirac puts it as follows: "We shall frequently have to consider the greatest possible number of independent compatible simultaneous observations being made on a system and shall, for brevity, call such a set of observations a maximum observation. When a maximum observation is made on a system, its subsequent state is completely determined by the result of the observation and is independent of its previous state. This may be considered as an axiom, or as a more precise definition of a state."


 * Now I see the problem with my phrase 'pure with respect to a particular sorting device'. It is incomplete. A pure state is pure with respect not only to one particular sorting device, but is pure with respect to every one of a complete or maximal set of commuting sorting devices.


 * I think it better that I do not directly answer your yes-no question, because, with respect, I think its formulation is faulty. Right here is not the place for me to say why I think so. I am of course afraid of a risk that this may exasperate you. I can only ask you to be patient, and read my just-above correction. Perhaps you may also wish to re-formulate your question.


 * Enough.Chjoaygame (talk) 17:31, 18 November 2015 (UTC)


 * No, I absolutely need you to answer, is this state,
 * $$\Psi(r, s_z) = \psi(r)\left(\frac{1}{\sqrt{2}}\left|\uparrow\right\rangle + \frac{1}{\sqrt{2}}\left|\downarrow\right\rangle\right),$$
 * pure? Is it mixed? I'll not read (I have glanced though it, I mean penetrate it) the wall of text above and try to figure out what it means. Just answer please, is the state pure or mixed? no experiments, no channels, no quotes. YohanN7 (talk) 08:47, 19 November 2015 (UTC)


 * Pure. Now you have established that you can hold a gun at my head and interrogate me without reading what I write, dismissing it as a wall of text. I trust that will make you feel better. Let's hope it may lead to some useful understanding as well.Chjoaygame (talk) 10:56, 19 November 2015 (UTC)


 * Thank you. It does make me fell better, but not for the reason you think. I'm not here to "win" any discussion, but I decidedly do not want the discussion to be pointless, because it would be a waste of time, yours and mine. We have had many discussions all over the QM talk pages, and more than once you have resorted to walls-of-text-and-quotes-out-of-context-by-10-different-authors tactics, often ignoring the real issue (diverting from the topic at hand)dismissing every statement that is mathematical. This has been frustrating. This is why I, to begin with, plead for a crisp and short "yes or no" answer. Naturally, you wrote back a wall. I saw no other way but to put that gun at your head. The other option would be to just go away. I'd rather not do that. I'll now read "the wall" above. YohanN7 (talk) 11:22, 19 November 2015 (UTC)


 * I'll get back in a few days with comments. No good computer access atm. YohanN7 (talk) 12:44, 23 November 2015 (UTC)


 * Ok. I read that an experiment has recently been conducted, depriving people of access to their computers (or was it just of access to certain apps on their hand-helds?) for a week or so, and seeing what it does to them. The result observed, I seem to recall, is that they feel a whole lot better about life. I suppose, or guess, that the result was an average, with wide individual variation. Perhaps my recall is inaccurate.Chjoaygame (talk) 18:11, 23 November 2015 (UTC)


 * I have not forgotten our conversation, but let's leave it resting for a while. My computer problems aren't resolved yet. By the way, the first week away from the damned thing is the worst. After a few weeks, things look much better indeed. YohanN7 (talk) 12:23, 1 December 2015 (UTC)


 * Thank you. I now think my recall was not quite right. I now think perhaps the experiment was not depriving them of their computer, but only of their social media, Twitter or whatever. But I don't really remember.Chjoaygame (talk) 13:28, 1 December 2015 (UTC)

an added voice
I hope that I am not out of place by interceding in your discussion, but I find it quite interesting. I am not as well read on the topic as the two of you appear to be, so I will withhold my own comments and viewpoints, at least for the time being. As I read the above, however, I keep asking myself if it would be easier to achieve consensus on the definition of a mixed state as opposed to a pure state. Any thoughts? JCMPC (talk) 03:49, 2 January 2016 (UTC)


 * You are welcome here, in this discussion.


 * I think consensus cannot be achieved here until it is well recognized that quantum mechanics is primarily a topic in physics, with mathematics as a most necessary, but not exhaustive, nor by itself sufficient, logical apparatus and form of expression. It seems to me at present that the mathematics-only approach has sway in this area in Wikipedia. At present it seems to me that egregious errors of physics are ignored or denied because they are not readily evident in mathematicized accounts.


 * I don't see that one can easily express the physical idea of mixed and pure states without physical ideas common to both kinds of state.Chjoaygame (talk) 04:49, 2 January 2016 (UTC)

second law of thermodynamics
Dear Editor Kingsindian, your presence as a disinterested observer/contributor was very helpful last time. If you have time again, I am sure your presence would again be helpful at Second law of thermodynamics.Chjoaygame (talk) 09:02, 3 February 2016 (UTC)

edits
hello. It's obvious that you think you own some of these articles, but you don't. Entropy is commonly understood as a measure of molecular disorder within a macroscopic system. It was not "undue detail"...but valid elaboration and from other WP articles themselves... No valid reason to rudely undo...because of "I don't like". Against WP policy....restored valid modification. You gave no actual rationale for your disrespectful reverting. Do it again, and you will be reverted again. Or go to Talk. Don't edit war.. Thanks. 71.183.133.173 (talk) 22:19, 12 February 2016 (UTC)
 * , don't forget WP:BRD since you are interested in behavioral standards. Different editors have different feelings about how much detail goes where...being "valid" doesn't make it indisputably appropriate. For the record, I agree that at least some of your insertions are excessive detail for the context. DMacks (talk) 22:30, 12 February 2016 (UTC)\
 * Hello DMacks. Frankly speaking, you can "agree" with a wrong revert all you want, but "I don't like" is not a WP valid reason for removing accurate, valid, good-faith, and/or sourced information and elabs...as it's just your OPINION that it's "unnecessary" or "excessive".  You "agreeing" uptightly about things like that don't have solid WP backing or recommendation. "I don't like" (which is really what it is, behind all verbiage) is not an argument.   This is a wiki. No one person owns any article.  Regards .... 71.183.133.173 (talk) 22:34, 12 February 2016 (UTC)
 * Do it's your opinion that it does belong. I never asserted bad-faith (in fact I noted the contrary) or that it is invalie or inaccurate. If you don't wish to collaborate and discuss, respect others' thoughts as you wish yours to be, and recognize that you might not be right about what should be in an article, then maybe wikipedia isn't for you. DMacks (talk) 22:36, 12 February 2016 (UTC)

promotion forbidden
Dear Editor Ariehbennaim, it is quite a thrill to see such an august personage as you contributing to the article entitled Laws of thermodynamics. It was also a little amusing to see that even the top brains can struggle with formatting Wikipedia references ! ! With much respect, however, though at first I will just say it here and not on the article's talk page, I think your edit is inappropriate and unethical. Having just now flicked through my copy of Lavenda, I am not impressed that it is a helpful reference for its relevant ostensible purpose, to let the reader check that just the customary four are listed, and other laws are not mentioned, in standard textbooks. First, it is not too easy to check that Lavenda lists exactly the four customary laws; for example, the index does not list the zeroth law. Second, Lavenda, at least in my opinion, is not a standard textbook. He is telling us he is non-standard by entitling his book 'A New Prespective ...'. Thirdly it is customary to limit lists of references of this kind to six, and yours is seventh. Fourth, it seems that you are promoting Lavenda more than intending to help the reader verify that standard texts list just four laws; in general, promotion is forbidden in Wikipedia, because it usually suffers from conflict of interest.

Therefore, with respect, I would urge to you remove that reference yourself before someone else does.

If you are really keen to have Lavenda's book cited, it should not be too hard to find a better way to do it. I see that it is cited in the article entitled Entropy for the statement "The concept of entropy arose from Rudolf Clausius's study of the Carnot cycle. " Personally, I avoid the article on entropy because I think it not a happy one. As usual, Rankine's nearly simultaneous use of his "thermodynamic function" is not mentioned. The best way to go would be to find something in Lavenda that is exceptionally simply and clearly expounded, and then find where in Wikipedia it is presented or ought to be presented, and cite it there. Simplicity and clarity are prime.

Chjoaygame (talk) 14:24, 8 February 2016 (UTC)

Abduction, induction, deduction and all that
Hi, let me reply here; I do not want to abuse the wavefunction talkpage. I'd say, your mind works over a continuous spectrum of meanings; mine - discrete. No, I am not a robot, I am a human, too; my mind switches to the continuous mode when reading poetry, or trying hard to find an approach to a mathematical problem. But when discussing some exact science with others (rather than feeling it within myself) I switch back to the discrete mode. Not being a poet, I am unable to speak in the continuous mode. Boris Tsirelson (talk) 21:27, 20 February 2016 (UTC)


 * Thank you for your reply, welcome here. I think I have made it clear that I hold you in high regard. I was, nevertheless, responding directly to what you wrote on that page. I think my response was fair. I think we have much in common, remembering that your mind is better than mine. One common thing that I think we have is that we don't let the Bell story make us believe in magic. I think Bell goes wrong in his passage from physical concepts to mathematical formulas. Once his formulas are granted, his story makes mathematical sense, of course. The physical problem is this: there are two sources of randomness in the story, the preparative source and the observing source. A question of causality has to refer to singular instances. That means the story must make sense for a single particular singlet pair. Classical mechanics can describe a vast range of things. That is its kinetics. But it is known that it can't describe quantum jumps, the phenomena of interest for Bell. The target that Bell attacks is not specifically classical mechanics: no, it is a certain metaphysical position. That position does not make all the assumptions that might be attributed to classical mechanics, rightly or wrongly. In particular, the metaphysical position under attack does not assume that experiments that cannot be conducted simultaneously can be conducted simultaneously. Classical mechanics does not postulate as a matter of physics that simultaneous measurements can be performed. It doesn't have postulates about such things. Just because its kinetics lets things be said, it doesn't mean that they are postulated to be actually realizable. It is not only quantum mechanics that says you can't measure position and momentum at once. It is common sense, including the common sense of that metaphysical position. Bell's argument has in the one formula things that cannot be observed at once. Therefore his formula cannot test causality, which demands things that happen at once. I think this is expressed by the idea    that Bell's $ρ(λ)$ cannot exist as he needs it. The sums come out right if you don't respect the demand that the quantities be measured at once. But that doesn't deal with the physical problem. I guess you may think I am mistaken about this.

References
 * Chjoaygame (talk) 22:17, 20 February 2016 (UTC)


 * I was just on the point of removing my comment about abduction from Talk:Wave function, then I thought I had better check with you that you don't object to me doing so. If you don't object, and no one else has replied, I will remove it.Chjoaygame (talk) 23:53, 20 February 2016 (UTC)


 * No problem, remove it there. Boris Tsirelson (talk) 05:57, 21 February 2016 (UTC)


 * Looking at your above comment, I am reminded that quantum mechanics demands quantum jumps, that cannot be explained dynamically by classical mechanics, though its kinetics allows descriptions of them, up to a point, if one allows Heaviside step functions and suchlike. As a matter of fact, quantum mechanics can't explain them either. Indeed it says nothing about them, except by virtually tacitly postulating them. That is the clearest reason for saying that quantum mechanics is an incomplete theory, though of course, because it's true and they don't want to hear it, no one says it.Chjoaygame (talk) 07:11, 21 February 2016 (UTC)

anecdotes
A real-life story. In 1980, in Soviet Union, I worked as a programmer; another programmer in our group, Misha, was my good friend. (Really, we two were the strongest programmers in that group.) Once upon a time I told him about Bell, and was very astonished by his reaction. He said: I see, in order to bound the probabilities we must use the quadratic programming, not the linear programming; why the fuss? I was very disappointed: my story was about the heart of nature... Well, I decided never to return to this topic with that person. Note however, that he was not aggressive; he did not say Bell is wrong, refuted, flawed etc. He just was not impressed. Accordingly, I was not furious, just disappointed.

Another story. Recently a younger colleague told me about two rejected manuscripts of two authors. They took for granted that empirical facts may be described in the language of observables, AND the observables may be treated as operators on a Hilbert space. Yes, the quantum theory claims it. The problem is that these authors did not work within the quantum theory. They took it for granted outside the quantum theory! (That is, in the context of arbitrary hypothetical theory.) Remembering your words about the fact of existence of non-commuting operators even in two dimensions, I guessed you are one of these two. But no; soon after I understood that you are not. It seems, you are the third person to think so. You like sources; well, try this:
 * Landau, "Experimental tests of general quantum theories", Letters in Mathematical Physics 1987, vol 14, 33-40.

Especially, Sect. 3 there.

I do not expect us to agree on Bell. Clearly we are much too different. Moreover, I doubt that we can agree to disagree. For me it is clear that what you claim is not a refutation of Bell. It is (re) assessment. You find his "local realism" axiomatics to be stupid. OK, I do not object; this is your right. But this is a personal attitude. (If someone finds Euclidean axioms stupid, then of course Euclid's theorems are of no interest to him; but not at all refuted.) I find that axiom very clever, in the sense that it conforms very good to my world-view before Bell. This is my personal attitude. Surely we agree that nature does not satisfy this axiom. Strangely, for me this is Bell theorem, while for you this is refutation of Bell theorem! I do not hope to understand, why. Boris Tsirelson (talk) 08:21, 21 February 2016 (UTC)


 * Thank you for these thoughts.


 * "my story was about the heart of nature... Well, I decided never to return to this topic with that person. Note however, that he was not aggressive; he did not say Bell is wrong, refuted, flawed etc."


 * Am I right to read in that extract that you find my response to Bell "aggressive"? Well, yes, I am disturbed by it because I think it misleads people very gravely. It leads people to think that somehow quantum mechanics has a metaphysical significance that I think it does not have. It thus licenses drivel. That is not good for science.


 * "(If someone finds Euclidean axioms stupid, then of course Euclid's theorems are of no interest to him; but not at all refuted.)


 * Are you casting me in the rôle of someone who finds Euclid's axioms stupid? Euclid wasn't muddled or misled. He was a genius. Bell is just incompetent at metaphysics.


 * ""Surely we agree that nature does not satisfy this axiom."

One more real-life story to this collection (a bit late). Several years I participated in a research in economics (namely, auctions theory), together with an economist. We spoke a lot about differential equations (for optimal strategies). Once upon a time I told him:

I: ...Not quite so; a function need not admit an explicit formula; most functions (exist but) have no individual "names", just like animals in the wild run irrespective of being known to any human or not.

He: No, you should be wrong; maybe it is generally so, but in the theory of differential equations all functions are supposed to be explicit.

I: why?

He: Here I read the textbook: "...when substituted into the equation, turns it into equality".

I: Sure. So what?

He: Substituted! You cannot substitute a nameless abstraction.

Being not a mathematician, he did not know how do we mathematicians use such phrases. Well, I smiled and told him so. He did not say me "I know you are an expert, but no, you cannot overcome the textbook". But you are another case. Knowing you I have a reason to worry that you may "win" our discussion by something like that. Very probably you can catch Bell on some unthinking phrase, or even an error. I do not care. Yes, I did not read Euclid, and still I understand his geometry reasonably good. The same for Bell. When I grasp the idea, I do not need the text. Boris Tsirelson (talk) 14:40, 21 February 2016 (UTC)

what axiom?
What axiom do you mean?Chjoaygame (talk) 10:40, 21 February 2016 (UTC)


 * "I think it misleads people very gravely. It leads people to think that somehow quantum mechanics has a metaphysical significance that I think it does not have."


 * Surely you know that for me this looks like "I think that two times two is five, five, five, FIVE!"


 * Now, one option for me is to follow your pattern: say "thank you for letting me know, once again, your opinion about Bell" and go away.


 * Is there another option? Let us think. I cannot just answer your question "What axiom do you mean?" because we have no common frame needed for any communication. If I'll answer in my language, you'll misinterpret it completely. In your language I am unable to answer, since my understanding of your language is as bad as your understanding of my language. "The signals and behaviors that cats and dogs use to communicate are different and can lead to signals of aggression, fear, dominance, friendship or territoriality being misinterpreted by the other species" (Dog–cat relationship).


 * Feeling this, I tried (long ago) to use the frame of everyday life as a common frame. I mean, my question about the time machine and the millionaire. Alas, this failed. Dog–cat relationship problem again.


 * I have one more proposal... but first, let me ask, whether you are still interested. And I need your consent to use my own formulations of Bell's axiom. If you intend to say "no, this is your OriginalResearch, Bell did not say so" then I see no more options. Boris Tsirelson (talk) 12:23, 21 February 2016 (UTC)


 * We here are discussing questions of science, not debating what should be put up on a Wikipedia page. So I have here no problem with original research, but we should avoid posting here things that we may subsequently wish to present as previously unpublished, because in a sense this is a public forum. Perhaps private email would be better.


 * As for the time machine and the millionaire. Recently I tried to sell another Wikipedia editor my patent anti-catalyst that stops hydrogen and oxygen from reacting. I asked for a $ 1000000 order, but he refused because he didn't have the cash. He did however, accept my offer, for a cheap price, to sell him a clock that is calibrated in units of Poincaré recurrence times. I sent it to him by Bell teleporting, expecting it to arrive 2 hours before I sent it, but sad to say he did not acknowledge receiving it.Chjoaygame (talk) 15:55, 21 February 2016 (UTC)


 * :-(  Boris Tsirelson (talk) 16:05, 21 February 2016 (UTC)

your own axiom
I am happy to read your own axiom. But I will read it on its merits as your own axiom. If you claim that it should be seen as a re-wording of Bell's axiom, I will read that claim on its merits. I won't uncritically accept a re-wording as being a true representation of Bell.Chjoaygame (talk) 15:55, 21 February 2016 (UTC)


 * Not very encouraging. Boris Tsirelson (talk) 16:15, 21 February 2016 (UTC)


 * Above you assume in advance that I won't understand your language: "If I'll answer in my language, you'll misinterpret it completely." I am chatting with you, Boris Tsirelson, not with Bell's ghost. Of course I will try to understand your language as yours. If I really misunderstand, the more silly me. I don't want to be silly.Chjoaygame (talk) 16:25, 21 February 2016 (UTC)


 * "Please don't spend more time on this; you have other things to do." I am inclined to follow your kind advice. One more Frustrating discussion will be too much for a single year. Boris Tsirelson (talk) 16:43, 21 February 2016 (UTC)


 * Oh, dear! Chjoaygame (talk) 17:37, 21 February 2016 (UTC)

duane's hypothesis
Dear Editor Grok42, it is very good to see your interest in the article Duane's hypothesis expressed on its talk page. As you seem new to Wikipedia editing, I hope you will be happy to have some friendly advice about the housekeeping of talk pages. I hope you will improve the article through your knowledge and care. With friendly intent, I need to tell you that your activities on the talk page have been very much out of order, in that you have edited comments by others. This is very much against the proper way to go. Your comments should be additions to the page, not alterations of it. I do not know how to remedy your actions. One way, perhaps the best, would be for you to undo your edit, and then write a new one in accord with accepted protocol, namely that you add whatever you like, but you do it following the already present comments,  not interfering with them in any way. I look forward to your valuable contributions. On the talk page it is very desirable, almost compulsory, that posts are signed by use of the four tilde sign. As far as I can see you have not signed your post at all.

After thinking it over, I am undoing your post. I have subsequently posted a copy-and-paste of your post, now in the proper place, at the bottom of the page. This is not an attempt to undo or interfere with your comments. It is an attempt to get things back into order after your very improper activities. I hope you will post anew to your heart's content, but this time following customary protocol. Added comments always go at the bottom of the talk page. Each new comment is indented by one more leading colon.Chjoaygame (talk) 08:29, 3 March 2016 (UTC)

reu lk
Editor Trackteur has removed a link.

Please excuse my lack of familiarity with Wikibreviations. I am guessing that "reu lk" means 'redundant use of linking' or something close? I am not exactly clued up on the rules for linking. I think a link there is not too far redundant. The point is that one is formally referring to established definitions, and the link intended that. Perhaps instead the text could read "A thermodynamically defined process consists of transfers of matter and energy between bodies of matter and radiation" ? I would prefer the former version: "A thermodynamically defined process consists of transfers of matter and energy between bodies of matter and radiation."Chjoaygame (talk) 23:27, 15 March 2016 (UTC)
 * Hi, reu lk is an error, must be understand rep lk (repetitive link). There twice on the same link thermodynamic process in the introduction, if you prefer it's possible to remove the other. Trackteur (talk) 07:32, 16 March 2016 (UTC)
 * Ok, I see where you are coming from. But I am not sure about it. It seems to me that a reader might be puzzled by 'reversible process' but not by 'transfers of matter and energy', or vice versa. That's why I linked both. Is there a strict rule for this?Chjoaygame (talk) 09:08, 16 March 2016 (UTC)
 * No. But you could linkreversible process (thermodynamics) where appropriate, and perhaps find a more spot-on link for 'transfers of matter and energy' or an explicit explanation of what it means. There is also no need to be very precise in the lead if the main text is precise. YohanN7 (talk) 09:29, 16 March 2016 (UTC)


 * Ah, yes, my mistake. The duplicate link was to Thermodynamic process. It doesn't seem to matter which one goes.Chjoaygame (talk) 13:17, 16 March 2016 (UTC)

Proposed topic ban on you to not edit quantum theory articles
I have proposed a topic ban on you here


 * Wikipedia talk:WikiProject Physics

for lack of productivity and effectively disruptive editing over such a long, long time. 'M'&and;Ŝc2ħεИτlk 16:17, 2 April 2016 (UTC)

Update on your topic ban
FYI, it has been moved to Administrators' noticeboard and will be continued there. 'M'&and;Ŝc2ħεИτlk 08:49, 3 April 2016 (UTC)

a gang
Editor PAR may perhaps be interested to learn, at least as I read the following, that he is accused of being a member of a gang. The gang action was here. The accusation is here. Oh, dear!Chjoaygame (talk) 17:12, 3 April 2016 (UTC)

comment by Editor Maschen

 * More of your opinionated diatribes?
 * You unearthed a past discussion just to accuse YohanN7 of screwing up.
 * Followed by ensuring to mention my misinterpretation on Talk:Bra-ket notation, and repeatedly harking back this again and again and again elsewhere, as if you knew what you were talking about all the time. Well, every time I have mentioned the concept of a basis (linear algebra) you ran off, so obviously you did not understand the incident on bra-ket notation and complex vectors either, only vacuously resorting to Dirac's book. 'M'&and;Ŝc2ħεИτlk 10:56, 5 April 2016 (UTC)

I have restored this comment that Editor Maschen self-undid. I do not reply to such comments on the main talk pages because they do not contribute usefully to those pages. But, Editor Maschen, I am responding to your transient post on my talk page, here and now. Regrettably, Editor YohanN7 has intervened as I was writing, and has removed from my talk page something that I legitimately restored to it. I have restored it again. The retraction was inadequate because it did not deal with the accusation's being a version of like unretracted accusations on general talk pages.

The reason I unearthed the aborted conversation with Editor YohanN7 is obviously not "just to accuse YohanN7 of screwing up". If that were an accurate statement of my intention, one would ask "Why now? Why not last month or next month?" Obviously the reason for my bringing it up now is self-defence, now.

In more detail, the reason for bringing it up now is stated above, copied here:

But you didn't get back. Just at the moment when a radical flaw in your thinking was exposed. The flaw was that you thought that a pure state could be produced just by by weakening the beam. That convinced me that, despite your mastery of mathematics, you really don't have a proper physical understanding. My view is that preparation of a pure beam requires selective filtration. From the oven, no matter how attenuated, without selective filtration, Nature supplies a beam that is mixed, not pure.

And now I have exposed a radical flaw in the thinking of another editor, this time a mathematical flaw, he proposes to have me banned, instead of admitting his error. It seems that the élite counter effective criticism by ignoring or banning it.

I have above, copied here, acknowledged that you magnanimously changed your mind:

To his credit, the mathematically flawed editor has now admitted his error.

Regrettably, I have seen no reason to believe that Editor YohanN7 has recognized or remedied the serious gap in his physical understanding that was revealed. You continue with the scheme of responding to effective criticism of the views of the élite, by banning it. The gap in Editor YohanN7's physical knowledge is material to the present attack that you have made on me.

Your next point is to allege I do not know what is a basis of a vector space, and vacuously resort to Dirac's book. You have previously made such an accusation. It is such an unfounded accusation that it would be a mistake for me to dignify it by responding directly to it as I may guess you might demand, with some exhibition of formula manipulation such that by which you tried unsuccessfully to defend you initial mistake. Nor do I intend to go into my personal qualifications, a thing not customary in Wikipedia talk pages. Your best and most dignified move now is to politely and explicitly withdraw your unfounded accusation, versions of which remain on the general talk pages.Chjoaygame (talk) 12:04, 5 April 2016 (UTC)


 * I did retract, YohanN7 also retracted, you're the one who reinstated it twice . In any case you are unbelievably ignorant of linear algebra or functional anlysis, and have no right to claim others favour "your mathematics" in a third opinion. 'M'&and;Ŝc2ħεИτlk 12:43, 5 April 2016 (UTC)


 * All this gabble
 * "Your next point is to allege I do not know what is a basis of a vector space, and vacuously resort to Dirac's book. You have previously made such an accusation. It is such an unfounded accusation that it would be a mistake for me to dignify it by responding directly to it as I may guess you might demand, with some exhibition of formula manipulation such that by which you tried unsuccessfully to defend you initial mistake."
 * is just another excuse for saying you "don't really know". This same kind of disguised gabble has occurred on every talk page you post on. At least I actually clearly say I know or don't know. 'M'&and;Ŝc2ħεИτlk 12:52, 5 April 2016 (UTC)


 * As I wrote above, an undo is not an explicit retraction. Your unfounded accusation is repeated, yet again here. A dignified response from you would have been an explicit retraction, not a repetion. Another editor cannot properly retract what you write on my talk page.


 * My refusal to respond to disorderly posts is the proper response to them. To respond to a disorderly post is to participate in disorder, and to reward it. Your above use of the phrase "all this gabble" is not fitting. I have already said that I do not respond to such unfounded accusations as you have made on general talk pages because it would be unhelpful. Since you repeat it again here, it seems I may usefully reply. It seems you need an explicit statement from me. Of course I know perfectly well what is a basis for a vector space. An explicit retraction is again your most dignified course.Chjoaygame (talk) 14:45, 5 April 2016 (UTC)


 * No, I am not going to take back what I said, especially after you put it back. You are taking every chance in every post to "prove" or "mention" the errors of others, like in the foregoing section, the admin page, Talk:Wave function, and Talk:Bra–ket notation.


 * If you can rub comments about me like (my underline added)


 * "And now I have exposed a radical flaw in the thinking of another editor, this time a mathematical flaw, he proposes to have me banned, instead of admitting his error . It seems that the élite counter effective criticism by ignoring or banning it."


 * "To his credit, the mathematically flawed editor has now admitted his error. "
 * in all our faces here and elsewhere, then expect me to stand against your touting, especially long past the incident. The purpose of a topic ban is NOT to censor out specific editors like you think. It is for the sake of article quality, and the collaborative environment. You have been damaging both long enough.


 * As this section shows, even a simple conversation with you is like talking to a brick wall (hence this summary). Unless it absolutely cannot be helped, I will not talk or respond to you, on any page for any reason. 'M'&and;Ŝc2ħεИτlk 17:09, 5 April 2016 (UTC)

locality, realism, freedom
Editor Tsirel rightly says that the topic ban page is not the place for a content dispute. He seems to agree with me, and others, that Bell's theorem does not establish action at a distance. I think that is the only strictly physical question. I think it coincides with locality. The other two concepts ('realism' and 'freedom') are loaded, fraught, enmeshed, entangled, saturated with nearly or perhaps actually unfathomable metaphysics. So loaded are they that I think it very difficult, even prohibitively difficult, to include them usefully in a discussion of physics as physics. I think Bell theorists mostly gravely underestimate that difficulty. They verge on arbitrary deduction from a contradiction. And seem hardly aware of the difficulty. Bottom line: I don't believe in magic.Chjoaygame (talk) 07:55, 5 April 2016 (UTC)

Concerning the adiabatic page
Hello, Chjoaygame. Go ahead and undo the page, but I do have some arguments to back my editing. I have to leave, and we can discuss it tomorrow. Tomorrow I will see a physics teacher and I will check with her. I am indeed new. You sounded a little angry on the talk page. If it is the case, I shall apologize. By the way, I am a lady, please use 'she' instead of 'he'. Have a nice evening. --Appleuseryu (talk) 17:17, 6 April 2016 (UTC)


 * Thank you for this response. Sorry to call you 'he' when 'she' was right. This is the first time I have been called out on that assumption.


 * Yes, perhaps I was too short in my comment, sounding a little angry. You should not apologize, you didn't do anything wrong. It remains true that your edit recurs and recurs. There is practically no prospect that it can survive.


 * For this kind of work, reasoned arguments of your own or of a physics teacher count for little in the face of reliable sources. Wikipedia is based strictly on reliable sources. In this case, you would need several very reliable sources. Not likely.


 * Still, for the present I will leave it to you to undo your own edit.Chjoaygame (talk) 17:33, 6 April 2016 (UTC)


 * Ok, I see you have done it. Well done.Chjoaygame (talk) 17:39, 6 April 2016 (UTC)

Seeking to be heard
Chjoaygame, you do not need to push the topic further. If you desire to be part of the community of editors, you can use the talk pages of the respective articles. There is plenty to do. We might find a topic to collaborate on, perhaps? --Ancheta Wis   (talk  &#124; contribs) 15:14, 3 April 2016 (UTC)


 * Ancheta Wis, thank you for this kind message. I have to confess, I have tried several times to nut out what might be the meaning of the fascinating words 'Ancheta Wis', but I have failed entirely. Perhaps you may see fit to enlighten me? As for the quantum mechanics thing, I am in the gun for excessive use of the talk pages. My edits are small in comparison. On the present specific point, I think it is clear that my edit is valid and notable. I think it would reflect badly on Wikipedia if I were banned for not accepting its being airbrushed out. We will see some developments, I suppose.Chjoaygame (talk) 15:29, 3 April 2016 (UTC)
 * Ancheta means 'a small gain', usually a small profit. Wis is Wisconsin, as opposed to Texas or California, where I have also lived. But my family is all over the globe. --Ancheta Wis   (talk  &#124; contribs) 15:46, 3 April 2016 (UTC)


 * Ah, yes, I vaguely and perhaps mistakenly seem to recall I found the Spanish word, but then the Wis didn't seem to follow. So I didn't cotton on to the whole.Chjoaygame (talk) 15:55, 3 April 2016 (UTC)

real and purely imaginary parts
Editor Guy vandegrift has always behaved towards me in a way that I much respect. And continues to do so.

I respond on this page here to his comment here because I don't want to fill the project page with things that don't belong there.

I copy-and-paste his comment here:


 * I followed the discussion between Tsirel and Chjoaygame on Bell's theorem, but was unable to ascertain whether Ch is or is not an "entanglement denier". It seems to me that Ch just likes to redefine terminology ( e.g. by replacing the conventional phrase "Quantum pseudotelepathy" with "absence of action at a distance" ). My unpleasant experience with Ch on Heat was partly my fault.  While three editors were involved, the third editor did not participate very much.  Chjoaygame's insistence on doing the lede his way was too much for me and I began to curtail my edits after that.  The problem with Chjoaygame is that he doesn't think like most (or nearly all) physicists.   The issue that caused me to vote for the ban on quantum articles wasn't rude behavior but his insistence that Dirac's bra-kets cannot have real and imaginary parts.  That issue suffers from a severe lack of WP:notability (the complex conjugate of a ket could be defined but nobody would want to do it) . Statements about notability involve opinions (not facts), and therefore such discussions need to end quickly.  His efforts to push such nonstarters on the talk pages makes it difficult to improve articles.  Aside: I also moved my Let me digress a bit to my talk page to make it easier to add comments to this discussion --Guy vandegrift (talk) 11:27, 6 April 2016 (UTC)

I would like to reply to his comment.

I don't exactly know what is an "entanglement denier". But I can say that I regard entanglement as a fact of nature. It was noted by the founders at the 1927 Solvay conference. It is manifest in the structure of the generalized quantum configuration space, which I regard as referring to fact, though only abstractly.

The term "quantum pseudotelepathy" is news to me as a term, though its meaning is obvious enough. I avoid reading the kind of literature that I suppose spawned 'quantum pseudotelepathy', because I find it full of what I call Bellspeak. 'Quantum pseudotelepathy' is an awful term, in my view. It leads in just the wrong direction. The rule against action at a distance is naturally physical. The term 'quantum pseudotelepathy' drags in all kinds of irrelevant and distracting allusions, many of them with hardly any connection with physics. It is not as bad as many Bellspeak terms, because it makes its fancy nature obvious up front. They build all kinds of more or less hidden non-physical assumptions into the language, and make it more or less impossible to think physically.

The term 'action at a distance' is I think very traditional. I certainly didn't invent it. I don't know the history of the term. I wouldn't be surprised to find it over 1000 years old, nor even 2000 years old. I know that Newton considered his law of gravity to suffer from the metaphysical defect that it expresses the same idea as action at a distance. I don't know the exact words he used. He took Aristotle as his source for that concern. It took till Einstein's general theory to remedy the defect. From the point of view of language, I think this paragraph is obvious.

As for what I call 'the Bell industry'. I regard causality as the underlying principle of science. Time and space are derived from it. Perhaps that is enough to make Guy think I am nuts. I think Editor T thinks I am nuts. This one is hard to formulate, and I am very concerned about it. I don't try to edit Wikipedia about it because I know how passionately the Bell guys feel, and because I don't feel yet that I have apodeictic arguments. No point in trying to pursue it here.

"The problem with Chjoaygame is that he doesn't think like most (or nearly all) physicists." Agreed. I would like to quote Dirac: "... Any student who is working for an exam must adopt this interpretation if he is to be successful in his exams. Once he has passed his exams, he may think more freely about it, and then he may be inclined to feel the force of Einstein's argument."

I don't recall the details of the dispute about the lead of the heat article. I am sorry I made it hard for Guy. There were various problems. I have now restored the sentence about state functions. I don't quite recall why it wasn't there. There have been many editors contesting that lead, with various agendas, including one or two who seemed to want to re-construct the English language.

"his insistence that Dirac's bra-kets cannot have real and imaginary parts". This one has me worried. Exactly what I claim is not in those words of Guy, but in slightly different ones: 'Dirac's bra-kets cannot be split into real and pure imaginary parts in the way that ordinary complex numbers can.' Guy's word "have" makes me unhappy, because I think it ambiguous. Kets can have representations that have real and imaginary parts; do the kets then "have" those same parts? I think Editor M (whose name should not be mentioned) now has it right, in his words: "To close up my comments to this page, and (attempt to) satisfy Chjoaygame as he unearths an old thread here, I admit blindly thinking a complex vector could be generally split into real and imaginary parts exactly as for complex numbers, for any basis. However, for the a + ib example above, I did state what the basis was (ex, ey, ez), so the vector could be written that way. If another basis was used then the components would be different. Me admitting this mistake ..." I would express that as 'a complex vector in general cannot be split into real and pure imaginary parts'. I think Dirac said that and meant it in the same way as I do. Perhaps Guy would like me to say instead 'a complex vector in general cannot be split into real and pure imaginary parts in an invariant way'. Happy to oblige, though I think it over-solicitous. Of course some complex vectors, if defined by coordinates, can be so split. As I read Guy here, he denies it in general. As did Editor M at first, and tenaciously; it was the trigger for this ban. Do I read Guy aright in this? If so, I have to say I think Dirac is right, and that since both Editor M (at first) and Guy deny it, that makes it notable. If chaps such as those don't find it obvious, and persistently deny it, it isn't obvious. Notable? As Guy says, that's opinion. My impression is that Guy denies it: "(the complex conjugate of a ket could be defined but nobody would want to do it)." That's a question of fact. I'd like to see it done in an invariant way. I think notability cannot be reasonably judged until factuality is correctly settled. If someone wrong in fact tries to determine notability, I think he lacks foundation. I don't want to see this spill back into the main pages. I'd rather drop it.Chjoaygame (talk) 16:11, 6 April 2016 (UTC)

Pronunciation of your user name
Hello Chjoaygame, how do you pronounce your user name? Maybe you could add the pronunciation to your user page. Petr Matas 19:50, 6 April 2016 (UTC)


 * Thank you for this question. The user name is just a string of letters. It has no natural pronunciation.Chjoaygame (talk) 19:55, 6 April 2016 (UTC)


 * What a disappointment that I can't get rid of this tongue-twister, :) but thanks for your answer anyway! Petr Matas 07:26, 7 April 2016 (UTC)


 * Yes, I also don't like it. When I created it I wasn't aware of the consequences of doing so. Silly me. I guess there might be worse consequences if I proposed to change it?Chjoaygame (talk) 08:29, 7 April 2016 (UTC)


 * Maybe it won't be that bad, see WP:UNC. Petr Matas 10:16, 7 April 2016 (UTC)


 * Predictions are always difficult, especially if they are about the future!Chjoaygame (talk) 10:20, 7 April 2016 (UTC)


 * You can also specify the pronunciation of your current user name and become proud of it. I propose // or //. Petr Matas 10:41, 7 April 2016 (UTC)


 * Thank you for these kind suggestions. At present, I think it probably best if I don't undertake new activities. Feel free to pronounce it as pleases you.Chjoaygame (talk) 12:31, 7 April 2016 (UTC)

Still in doubt on Guy vandegrift
"his insistence that Dirac's bra-kets cannot have real and imaginary parts". This one has me worried. Exactly what I claim is not in those words of Guy, but in slightly different ones: 'Dirac's bra-kets cannot be split into real and pure imaginary parts in the way that ordinary complex numbers can.' Guy's word "have" makes me unhappy, because I think it ambiguous. Kets can have representations that have real and imaginary parts; do the kets then "have" those same parts? I think Editor M (whose name should not be mentioned) now has it right, in his words: "I admit blindly thinking a complex vector could be generally split into real and imaginary parts exactly as for complex numbers, for any basis. However, for the a + ib example above, I did state what the basis was (ex, ey, ez), so the vector could be written that way. If another basis was used then the components would be different. Me admitting this mistake ..." I would express that as 'a complex vector in general cannot be split into real and pure imaginary parts'. Of course, the words 'in general' are vital: plenty of kinds of complex vectors can be split into real and purely imaginary parts, but some kinds can't, for example, as Dirac says, bras and kets. Perhaps Guy would like me to say instead 'a complex vector in general cannot be split into real and pure imaginary parts in an invariant way'. Happy to oblige, though I think it over-solicitous. As I read Guy here, he denies it in general. Do I read Guy aright in this? My impression is that Guy denies it: "(the complex conjugate of a ket could be defined but nobody would want to do it)." I'd like to see it done in an invariant way for bras and kets.Chjoaygame (talk) 01:38, 10 April 2016 (UTC)

remark
Editor Tsirel writes: "But if you define a pure state as corresponding (you know in which sense) to a possible value of an observable, then inevitably you enter such questions."

I wouldn't have used those exact words. I would have said 'You might propose to define a pure state as one for which in principle there is a sorting apparatus that will pass it with probability one, and will pass no other state. To be practical, this is understood by Dirac to include complete or maximal sets of sorting apparatuses that test component degrees of freedom separately, one by one. The pure state must pass through each of them with probability one, whole no other state does so. The question is unanswered as to the real physical existence of degrees of freedom for which no sorting apparatus is feasible in practice.' As Editor Tsirel notes, for the mathematical theory, it is convenient to ignore the reservation that some degrees of freedom may lack practically feasible sorting apparatus.

As I read Editor Tsirel, he warns against too much reliance on empirical definition. Fair enough. I agree that there are many acceptable pure states for which no single sorting apparatus is feasible in practice; indeed, in practice, such are most cases. As for single degrees of freedom for which no sorting apparatus is practically feasible, I am not too fussed. Perhaps some reason may emerge as to why I ought to be fussed? In the meantime, I am happy enough with the phrase 'in principle'.

A big problem is that Dirac, and significantly many present-day textbooks, refer to effects of the sorting apparatuses as "measurement"; like it or not, that term is widely used in the literature, and is traditional. I think it a harmful tradition, and I protest against it. But I can't change it.Chjoaygame (talk) 03:07, 10 April 2016 (UTC)


 * "test component degrees of freedom separately, one by one"?? Do you mean that all pure states are product-states (with no correlations)? Surely not, since you write you do not deny entanglement. Then, what do you mean? Boris Tsirelson (talk) 06:26, 10 April 2016 (UTC)


 * Thank you for this very kind and valuable reply. I have to say I hadn't thought of that. You are saying that for a pure state, with many degrees of freedom, the degrees of freedom are phase-linked in a way uniquely characteristic of that state. Therefore they must be tested jointly by a device that has no incompatibilities between its various stages, if it has stages; all the effective physical components of the sorting apparatus must be characterized by jointly commuting operators. I suppose that would make it very hard to design and build in practice. Perhaps impossible for most cases. I suppose that in practice, the various states that pass a physical sequence of separate degree-of-freedom sorting devices will in general be mixed with respect to phase-relations between the degrees of freedom? That seems to be adding up to meaning that, beyond the very simplest systems, with very few degrees of freedom, it is getting close to impossible in practice to prepare a pure state? Let me think about this a moment. By a very simple system, I mean, for example, electrons in a beam, or photons in a beam. Perhaps protons or neutrons have internal degress of freedom that make it practically impossible to prepare them in a beam in a pure state? What about hydrogen atoms in their ground state? Impossible, I guess. I already knew that more complicated pure states, of objects such as water molecules, would be practically infeasible to prepare.


 * For the moment, tentatively, let's say that (most or all) pure states cannot be prepared in practice. This means that one needs in general to define a pure state as an abstraction. One would say it is constructed as an equivalence class of a suitable sort of actually preparable mixed states, or some such abstract object? This is a job for a mathematician. Ok, time for you to comment.Chjoaygame (talk) 07:18, 10 April 2016 (UTC)


 * I guess you may say I am starting from the wrong end. I am taking the really existing entities to be physical, the can be observed to some degree empirically. You may say that one should start with the fundamentally contemplated objects as abstractions, mathematical objects. One will then go into the lab, and hunt around for phenomena that seem to be compatible with a chosen abstraction of interest, but one will not expect to find single occasions of experiment, meaning single particle detections, that fully realize it.


 * I would say, whichever end one starts from, one needs to have a good link to the other end.Chjoaygame (talk) 07:49, 10 April 2016 (UTC)


 * Many problems... Now I have many ends to start...
 * Well, first: "a pure state ... is constructed as an equivalence class of a suitable sort of actually preparable mixed states" — absolutely no. The singlet state, for instance, is pure, and I do not see any way to reduce it (in any reasonable sense) to any mixed states. Nor to any product (=factorisable) states, be they pure or mixed.
 * Second: "What about hydrogen atoms in their ground state? Impossible, I guess." — Why?? Very easy. The ground state is not degenerate, thus, pure, and its preparation is basically, cooling. To the temperature that makes the contribution of excited states very small. (Surely, nothing at all can be made exact in reality.) "Perhaps protons or neutrons have internal degress of freedom" — sure; quarks and gluons (mostly); "that make it practically impossible to prepare them in a beam in a pure state?" — again, "why??"
 * A hydrogen atom in its ground state could not pass (100%) your filter because of correlations between (first of all) the nucleus and the electron. Nor a proton, because it is correlated with the electromagnetic field around. Nor even its infernal majesty, the vacuum! Because, according to Summers ans Werner 1985,87, Bell inequalities are violated (and even, maximally violated) in the vacuum! Indeed, entanglement is alpha and omega of the nature.
 * It is a bad idea, to treat "practically possible" too much related to the practice of this century. Really, now in 21 century physicists really prepare states unthinkable in 20 century.
 * "(most or all) pure states cannot be prepared in practice" — Not "all" (see above); but "most", indeed, in a sense stronger than your idea of "practice". Here is what I mean. Consider 1000 qubits (say, spins 1/2). Their Hilbert space is of dimension 21000. Nothing can be made exact, so, let us try to prepare an arbitrary state with a moderate error, corresponding to the angle about 0.1 (radian) in the Hilbert space. How many balls of radius 0.1 can cover the unit sphere in this space? Roughly, 22 1000 . And how many classical devices are potentially possible (as alternatives, not coexisting) within a laboratory of size 100 billion light-years? Something like 1010 120 . Hopelessly little. Most of these pure states cannot be prepared.
 * Boris Tsirelson (talk) 09:12, 10 April 2016 (UTC)

To avoid edit conflict I have posted fragmentary comments in my talk archive 4 here.Chjoaygame (talk) 10:06, 10 April 2016 (UTC)
 * But my "to be continued" was removed before your remark above, and since then, you are free to write here. Boris Tsirelson (talk) 10:21, 10 April 2016 (UTC)


 * Still please look at the archive 4. It's empty except for my fragment reply.


 * After looking at your "fragmentary comments": sorry, I have too little motivation to read Hintikka. But you write "The singlet state may be pure, but can it be prepared?" which alienates me. The singlet state was really prepared in many laboratories many times, especially in Bell-related experiments, and no Hintikka can make me doubt... If you want to interact with physicists, please be closer to their world, otherwise they'll just shrug (and I, too). Boris Tsirelson (talk) 10:34, 10 April 2016 (UTC)


 * Thank you for this. You dismiss my stuff. Yes, they have an atom in a trap. They hit it to lift it to a state that will decay in two steps. But looking at only one of the output arms, one finds the successive photons unpolarized. I don't see that as a pure state. They want me to see it as a pure state, I know. I repeat my question about the Born rule referring to just one detection of the system as a whole.


 * As for Hintikka, he is a mighty intellect. I think he has pretty well superseded the mathematical logic of the time before 1970. Not negated it, but generalized it in a non-objectionable way. I think Hintikka will not conflict with your beliefs. It's just logic, not physics.Chjoaygame (talk) 10:56, 10 April 2016 (UTC)


 * New set of replies. "A hydrogen atom in its ground state could not pass (100%) your filter because of correlations between (first of all) the nucleus and the electron." I don't have any filter in mind for this. That's why I thought it couldn't be isolated in a pure beam. Could the spin of the proton in the hydrogen atom be observed in some way that would allow a filter? The spin of an isolated electron cannot be observed, at least according to standard texts? Does an isolated electron have a spin that counts as a degree of freedom?


 * You talk of advanced things, beyond my immediate intuition. You write "Consider 1000 qubits (say, spins 1/2)." I have to say that looks like an abstraction to me, and I have little idea of what it might mean in practice. At that point I stop thinking of it as physics. Is it a set of 1000 silver atoms each pinned to a site in a crystal, that somehow one can probe for spin, atom by atom?Chjoaygame (talk) 10:32, 10 April 2016 (UTC)


 * See quantum computing. Yes, a quantum computer is not at all built. But experiments with 2, 3, 4, not sure maybe 5 or 6 qubits, are really performed. Leave Dirac and Hintikka, get acquainted with laboratories. Boris Tsirelson (talk) 10:38, 10 April 2016 (UTC)


 * Ok, thank you for this.Chjoaygame (talk) 11:04, 10 April 2016 (UTC)


 * Now, the first (and probably the last) time in my life I regret that I have no Dirac at home. I cannot believe that he never mentioned the singlet state (or another pure and not factorisable state of a system). But you deny existence of such states!! Absolutely puzzling. Do you say "unfortunately, my dear Dirac is mistaken here"?! Boris Tsirelson (talk) 13:15, 10 April 2016 (UTC)


 * Thank you. I wasn't expecting a further reply from you.


 * Thinking it over, I do now recall that I puzzled over the following, without feeling settled about it. Many wave functions represent one and the same state vector. What about phase relations? I think that important, but I will put it on the back burner right now, and attend to your just above response.


 * A free searchable legal public downloadable Dirac 1958 4th edition pdf is as follows:

.


 * So far as I know I do not deny the existence of such states. I wrote on the archive 4 page: "The singlet state may be pure, but can it be prepared?" I am in much doubt about the physical meaning here. That is why I am asking about what replaces the Born rule when two detections are made on the one system. My reading of the canonical Born rule is that it is for just one detection. No mention of two detections. This is close to what you are saying about Dirac, who so far as I recall, subject to correction, does not talk about singlet states. It is not good to be sarcastic here. Dirac is about the only source I know, other than Feynman, who says much that I can understand about the relation between the mathematical objects and the occasions of experiment. Dirac is said by both Einstein and Heisenberg to be the most logical and reliable source. I think Dirac fails in a certain non-fatal respect that I will not detail now. I don't think he is an infallible god, but he is the best I know. If you can do better for me, I am all ears. Again, if I have said something that seems to deny the existence of pure entangled states, I don't intend it. I did say I don't see how they can be prepared. I accept that seems like a contradiction from me who says that pure states can be prepared. I mean that pure states can, in principle, be prepared as states detected once. But as states that can be detected twice, I am deeply puzzled. I think an upgraded version of the Born rule is needed, and I don't know how to make such an upgrade, nor have I read of it. An example of a state that can be detected twice is a singlet pair with spatially separated parts.Chjoaygame (talk) 14:32, 10 April 2016 (UTC)


 * I have now seen your posts and edit summaries on the Administration page. That explains to me why you feel you need to be sarcastic here. I started this coversation here because it was by then obvious that the topic ban would be enacted. No hard feelings. I don't know the rules: likely enough, the topic ban would extend to my talk page? Well, it hasn't been enacted at this moment.Chjoaygame (talk) 15:02, 10 April 2016 (UTC)


 * A bit about preparing singlet states and purity. Without prejudice, singlet entangled states are prepared. Without advance prejudice, they may be mixed or pure. Some reason or criterion is needed to decide which. The Dirac procedure for preparing pure states is to select them by a sorting apparatus from a mixed beam coming out of an oven. Singlet pairs come from, for example, an atom in an excited state that will decay in two steps. Then the two separate photons are observed by separate respective analyzers and detectors. The atom in the excited state is in effect the oven. Each photon encounters just one analyzer. Is that analyzer in the preparation side or the observing side? What is the criterion that decides whether the state is mixed or pure?Chjoaygame (talk) 16:11, 10 April 2016 (UTC)

prevent edit conflict
Here I copy from my talk archive 4:


 * Elaborating a bit on the above. For a pure state, it is necessary, but far from sufficient, that it pass with probability one through all the members of a complete set of compatible and suitable sorting apparatuses, one for each degree of freedom, each separately. I might pass the systems through one sorting device at a time, and detect the particles on each passage. I would do that one-by-one test for every member of the complete set. This wouldn't uniquely identify pure states because the phases are not even remotely coherent. But it would rule out many other states.


 * In my lab I have a locked cupboard that holds a set of frictionless pulleys, massless inextensible strings, perfectly Hookean springs, lossless linear capacitors, and clocks calibrated in units of Poincaré recurrence times, whatever. Using these I might try to chain all the separate sorting apparatuses one after another, and have one detector at the end. If this can be done without exposing the passing systems to objects characterized by operators that don't commute with all of my sorting devices, I think this would produce something useful. I don't know if the whole chain of devices would maintain mutual phase coherence, but it would need to so to fix a truly pure state. The pure states must pass the whole set at once with probability one. No other state does so. This is idealized, and mostly unfeasible. I don't recall reading about such things.Chjoaygame (talk) 09:59, 10 April 2016 (UTC)


 * Replying to your post on the fly. Yes, an equivalence class wouldn't do it. That's why I added "or some such abstract object" and stopped to ask for mathematical help. I think some logical apparatus is needed, but right now I have no inkling what.


 * The singlet state may be pure, but can it be prepared? The singlet state needs two detections to investigate it. The Born rule contemplates only one detection, of the whole system at once. The Born rule, so far as I know it, does not cover two detections, of two different parts of the system. I feel very puzzled on this point. Jaakko Hintikka has a new logic that uses branched existential quantifiers. Best I refer you to his Principles of Mathematics Revisited, Cambridge University Press, Cambridge UK, ISBN 0-521-49692-6, Chapter 3. It's called Independence Friendly, or IF, logic. Best I don't try to expound it here. I would likely mess it up. My reading of it is that it can deal with macroscopic ordinary situations that the usual Frege, Whitehead, Russell, Hilbert, Ackermann logic can't handle. Nothing mysterious about it. No amazing things. It's just that it allows branched sentence structures. He does mention possible applications to quantum theory, but the IF logic is neither derived from that, nor designed for it. That's considered in Chapter 4. I don't remotely recall the details. Would there be an independence friendly probability theory? Would it give a meaning to an upgraded Born rule with two detections per system?Chjoaygame (talk) 09:59, 10 April 2016 (UTC)

comments on Fano (1957)
According to ter Haar, D. (1961), 'Theory and applications of the density matrix', Reports on Progress in Physics, 24(1): 304–362, p. 315:


 * ... The pure state is characterized by the existence of what Fano (1957) calls a 'complete' experiment; this is an experiment which gives a result predictable with certainty when performed on this state and gives this particular result only for this particular state. The possibility of such an experiment is apparent if we bear in mind that it is possible to find a Hermitian operator, corresponding to a physical observable, which possesses this particular state as a (non-degenerate) eigenstate. This complete experiment can be used as a filter. It should be an experiment designed to measure the observable, of which $ψ_{0}$ is an eigenfunction. ...

Chjoaygame (talk) 12:54, 13 April 2016 (UTC)

According to Cohen-Tannoudji et al., p. 307:


 * References and suggestions for further reading:
 * Articles by Fano (2.31) and Ter Haar (2.32).

P. 876:


 * (2.31) U. FANO, "Description of States in Quantum Mechanics by Density Matrix and Operator Techniques", Rev. Mod. Phys., 29, 74 (1957).


 * (2.32) D. Ter HAAR, "Theory and Applications of the Density Matrix", Rept. Progr. Phys., 24, 304 (1961).


 * <. Translated from the French by S.R. Hemley, N. Ostrowsky, D. Ostrowsky.>

Chjoaygame (talk) 13:11, 13 April 2016 (UTC)

Community ban from quantum theory
Per this discussion at the Administrators' noticeboard, you are indefinitely banned from editing quantum theory articles or their talk pages. The ban has been recorded in WP:Editing restrictions and can be enforced with blocks by any administrator. Please let me know if you have any questions. Thanks, EdJohnston (talk) 14:18, 13 April 2016 (UTC)

Faddeev 2009
Faddeev, L.D., Yakubovskiǐ, O.A. (2009), Lectures on Quantum Mechanics for Mathematics Students, translated by H. McFaden, American Mathematical Society, Providence RI, ISBN 978-0-8218-4699-5, pp. 6–7:


 * § 2. States
 * The concept of a state of a system can be connected directly with the conditions of an experiment. Every physical experiment reduces to a measurement of the numerical value of an observable for the system under definite conditions that can be called the conditions of the experiment. It is assumed that these conditions can be reproduced multiple times, but we do not assume in advance that the measurement will give the same value of the observable when the experiment is repeated. ...




 * We shall consider that the conditions of the experiment determine the state of the system if conducting many repeated trials under these conditions leads to probability distributions for all the observables. In this case we speak of the measurement of an observable $f$ for a system in the state $ω$. More precisely, a state $ω$ on the algebra $$\mathfrak U$$ of observables assigns to each observable $f$ a probability distribution of its possible values, that is, a measure on the real line $R$.

Not too far from Fano.Chjoaygame (talk) 16:12, 21 April 2016 (UTC)

the term 'Copenhagen interpretation' was invented
Editor William M. Connolley has deleted the statement that the term 'Copenhagen interpretation' seems to have been invented by Heisenberg in about 1955, with his edit summary saying it was "faux history" contradicting the lead. The lead talked about the content of the interpretation, not its eponymous label. The so-called 'Copenhagen interpretation' is more or less the thinking of Heisenberg, Bohr, Born, perhaps with a touch of Dirac and others, more or less patched together by the time of the fifth Solvay conference. But the ideas were not labeled "Copenhagen interpretation" till Heisenberg invented the term in about 1955. He very shortly afterwards wrote that he was sorry he invented the label, because its existence suggested that the matter might be open to other "interpretations". The deleted statement was a loosely worded and unreferenced, but was substantially true and not wrong or misleading. Don Howard would be a suitable reliable source.<Howard, D. (2004), 'Who invented the "Copenhagen interpretation"? A study in mythology', Philosophy of Science, 71(5): 669–682; pp. 675–676: "Everything not found in Bohr’s complementarity interpretation is found in the writings of Heisenberg, and (so far as I have been able to determine) Heisenberg ﬁrst introduced the term “Copenhagen interpretation” in 1955. Simply put, the image of a unitary Copenhagen interpretation is a postwar myth, invented by Heisenberg. But once invented, the myth took hold as other authors put it to use in the furtherance of their own agendas. The setting for the invention is Heisenberg’s contribution to a volume of essays in Bohr’s honor."> Looking further in the article I see that this story is told with a reference to this paper of Howard.Chjoaygame (talk) 15:53, 21 April 2016 (UTC)Chjoaygame (talk) 16:02, 21 April 2016 (UTC)

pure and mixed states
It seems there are three different ways of defining a pure state.

(1) a pure state is one that has a representative that is a solution of the Schrödinger equation in some representation and coordinate system for the species. Such a state may be defined as the equivalence class of all canonical transforms of that representative, that is to say, all the alternative representatives that are also solutions of the corresponding transforms of that Schrödinger equation, in the corresponding representations. Mixed states are generated from pure states.

(2) a pure state is defined by a particular eigenvector and eigenvalue of a chosen maximal/complete observable. Mixed states are generated from pure states.

(3) a pure state is defined by a statistical operator $ρ$ such that $ρ^{2} = ρ$. It has one eigenvector with eigenvalue one. Thus pure states are special cases of states in general, which are defined by general statistical operators, and are mixed except for the special cases. In a sense, pure states are distilled from general mixed states.

Each of these ways has its merits and demerits.Chjoaygame (talk) 22:00, 22 April 2016 (UTC)

User:174.3.155.181
Dear User:174.3.155.181, it would be much more comfortable for other editors if you would very kindly give yourself a user name. If you choose one that will not suggest your identity, then you will have anonymity and security. I was baffled that you mentioned me on the Radon measure talk page, and didn't work out why, till by chance I noticed a like IP address, user:174.3.155.181, on the Talk:Entropy page.

I am not clued up on Radon measure and think it better I do not comment on it.Chjoaygame (talk) 19:30, 28 April 2016 (UTC)

Ontology
Two wikipedia articles that point to ancient works are linked: Tattva and Mimamsa. Please take a look at those two and references. If you think they are insufficient, please let me know why. I can provide more references. ~rAGU (talk)


 * Thank you for this response. It is customary to put a new post at the bottom of the page, like this, not at the top.


 * Wikipedia is not a reliable source. A link is not a source. An important post deserves good sourcing of its own. If all you want is to point to another article, See also is the way. Removal of a request for reliable sourcing customarily requires actual posting of reliable sourcing, and acceptance of it. Though my interest in these matters has led me to make a start at studying Sanskrit, I am far from well-informed on them. My judgment about reliable sourcing will not be nearly as good as yours, I suppose. Experience and judgment are needed for reliable sourcing. The source should explicitly support the statement that it covers. I expect you will be able without too much trouble to offer one or two references from reliable sources, explicitly supporting the statement you have posted. I guess you are the best person to do it.Chjoaygame (talk) 00:55, 14 March 2016 (UTC)


 * I have again posted a 'citation needed'.Chjoaygame (talk) 23:33, 15 March 2016 (UTC)
 * Thank you for the patience. I have to pick a couple from the ones cited in the  articles I linked. I will try to do that. It has been a while I edited or used Talk. Sorry for messing up the page. ~rAGU (talk)


 * Thank you for your response. No worries. You didn't mess up the page. I didn't mean to hassle you. But I didn't want you to forget.Chjoaygame (talk) 04:32, 16 March 2016 (UTC)


 * Editor Raguks, may I remind you about this. I have looked again at the links you offered as sources for your post in the sub-section Origins of the section History in the article Ontology. I think those links are not adequate as sources for your post. The links you offer are to very general articles, in which the specific tie to ontology is not easily seen. More importantly, even if it were more easily seen, a Wikipedia article is not a reliable source. Your post is important and deserves good sourcing. Specifically or explicitly supportive reliable sources are needed. You are the best person to do it.Chjoaygame (talk) 04:03, 3 April 2016 (UTC)
 * Chjoaygame I will do it. But I politely disagree that entire article and list of sources are nor "particular". Western folks always think the world somehow started in 15 century. Everything else needs evidence. I will however add references. ~rAGU (talk)


 * Thank you for this. Some time ago I fought to make it clear, in one of these articles, I forget which, that the start with Greek philosophy was based on only sources derived from Greek works, because I knew that Indian sources we probably earlier. I didn't know enough about it to prove it by adequate Indian sources. But I still thought that they would probably exist if one knew how to find them. And fought to make the point. Still it holds that a Wikipedia article is not a reliable source. All kinds of nonsense can be found in Wikipedia articles. That is not confined to any special area. The idea is that a Wikipedia reader should be able to verify the sourcing himself. Maybe a bit unrealistic. I think it fair to say that the articles you link to would call for the reader to do a lot of study to find the tie to ontology. Maybe, or maybe not. Either way, specific explicit reliable sources are the right thing. Your point, I think, is good, and could be expanded if well sourced.Chjoaygame (talk) 05:23, 4 April 2016 (UTC)

Temperature (again :) )
Would you mind taking a brief look at the temperature page? There was a recent edit to the lead statement that I am not quite comfortable with, and I would very much appreciate your opinion. — Preceding unsigned comment added by JCMPC (talk • contribs) 17:21, 3 August 2017 (UTC)

Looking back
Dear xxxx, you weighed in to have me banned from writing on quantum mechanics because of your conflict about heat and temperature.

Looking back on the heat/temperature thing, I think you may see that you were wrong and I was supported by reliable sources that you had not studied, and by long-established consensus on the talk page that you had ignored. You relied on your supposed self-authority as an established tenured professor. Reliance on supposed self-authority, against reliable sources and talk-page consensus, is unWikipedic.

So it was a double injustice that you perpetrated against me. One, the heat/temperature thing was irrelevant to the quantum mechanics thing. Two, you were wrong about the heat/temperature thing.Chjoaygame (talk) 20:24, 2 January 2018 (UTC)

A page you started (London and Newcastle Tea Company) has been reviewed!
Thanks for creating London and Newcastle Tea Company, Chjoaygame!

Wikipedia editor Blythwood just reviewed your page, and wrote this note for you:

"I've added an extra source."

To reply, leave a comment on Blythwood's talk page.

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Blythwood (talk) 18:51, 3 February 2018 (UTC)

Capitalization of kilo
Thanks for correcting the mistake I made when I changed k to K in Temperature. I had incorrectly believed that positive powers were capitalized, and negative powers were not, until I read the article Metric prefix. Thanks for teaching me something, and for all your other contributions to Wikipedia. Comfr (talk) 19:35, 27 February 2018 (UTC)

Reported to administrators notice board
There is currently a discussion at Administrators' noticeboard/Incidents regarding an issue with which you may have been involved.  Waleswatcher  ( talk ) 19:09, 19 April 2018 (UTC)
 * The post in question is this section  ►К Ф Ƽ Ħ◄   20:29, 19 April 2018 (UTC)
 * Noted.Chjoaygame (talk) 00:29, 20 April 2018 (UTC)