Wikipedia:Reference desk/Archives/Science/2022 January 21

= January 21 =

Schrödinger's cat = Checking whether a coin is fair??
Why Schrödinger's cat is treated different from coin flipping? They both have 2 possible outcomes. One is treated as though experiment, other one falls under Maths. Rizosome (talk) 03:51, 21 January 2022 (UTC)


 * See Qubit. --Cookatoo.ergo.ZooM (talk) 05:47, 21 January 2022 (UTC)

But I am not asking units of Quantum information. Rizosome (talk) 11:14, 21 January 2022 (UTC)


 * The uncertainty in a coin flip can be attributed entirely to the experimenter's lack of knowledge about the physical state of affairs at the instant the coin is released, such as its precise velocity, momentum and angular momentum. Given all relevant values (which should also include the movement of atoms in the coin, the air, and the object on whose surface the coin should land), the outcome is determined by the laws of classical physics. With some effort, an experimenter can train themselves to flip a fair coin so as to produce a biased outcome; see . For the quantum equivalent, even if the precise initial physical state is known, the outcome is still not determined (at least, in the Copenhagen interpretation); see Bell's theorem. The uncertainty of the fate of the cat is not due to a lack of knowledge, but is inherent in the laws of physics as they are currently understood. --Lambiam 12:01, 21 January 2022 (UTC)
 * It is worth noting, however, that an actual cat is a (deliberately) bad example for quantum superposition: it is always either dead or alive; undead cats do not exist in reality (see quantum decoherence for more on this). Cheers ❖hugarheimur 13:23, 21 January 2022 (UTC)

I understand that Schrödinger's cat and Coin flipping are not same from this line: With some effort, an experimenter can train themselves to flip a fair coin so as to produce a biased outcome; see. Rizosome (talk) 09:19, 22 January 2022 (UTC)


 * As pointed out here, it's actually exactly the same, because all probabilities in the natural world ultimately originate from quantum fluctuations. A probability due to a lack of knowledge falls into the same category, as it's ultimately due to a lack of correlations between the brain processes that initiate a certain action and the resulting outcome of e.g. a coin flip. The randomness in the brain processes have a quantum mechanical origin. Count Iblis (talk) 21:16, 22 January 2022 (UTC)
 * In a game like Let's Make a Deal, in which a rational player needing to solve the Monty Hall problem should base their rational computations on probability theory, and more specifically the rules of conditional probability, the player's lack of information concerning the prize-carrying choice when offered the opportunity to switch after one choice is shown to be a dud is not due to quantum fluctuations. And if superdeterminism reigns supreme, quantum fluctuations are a mirage due to our lack of information. --Lambiam 14:34, 23 January 2022 (UTC)


 * Previous answers are correct, but to emphasise: Quantum Mechanical randomness is true randomness. It is a fundamental part of the Universe. In this type of randomness, even knowing everything there is to know about a system, you cannot know with certainty the outcome of a measurement before you make it. Coin flipping is more of a perceived randomness - in a sort of chaotic way, small changes in initial conditions become large changes in the outcome, making the outcome hard to predict and thus appear as random. I might call this statistical randomness - the outcome of a coin flip is, in statistical talk, a random variable. (A subtle point is that the two coexist - the coin flip will be affected, in perhaps imperceivable ways, by Quantum Mechanical randomness.) — Jthistle38 (talk) 22:33, 26 January 2022 (UTC)

Does colored newspaper ink contain heavy metals?
I was told that the colored ink in newspaper contained heavy metals (and to keep those pages out of the garden). That was a long time ago. There is now a lot more color in the newspaper. Are they still based on heavy metals? Thank you. RJFJR (talk) 04:30, 21 January 2022 (UTC)


 * Not according to this source: "Today’s newspaper uses ink that is 100 percent non-toxic. Inks of all colors and black and white are included." What I see in sources is that volatile organic compounds are considered more of a problem than pigments, an issue that is resolved if the newspaper uses soy ink. But this source mentions cadmium yellow as a common newspaper-ink pigment; the heavy metal cadmium is toxic. --Lambiam 12:32, 21 January 2022 (UTC)
 * So are non-coloured newspapers now safe for Fish and chips as they were in my youth? Martin of Sheffield (talk) 14:26, 21 January 2022 (UTC)
 * Perhaps if liberally sprinkled with salt and vinegar. What was considered safe in your youth may no longer be generally recognized as safe today, though. --Lambiam 14:17, 23 January 2022 (UTC)
 * At the time of chips-in-newspaper (before about 1970?), they were cooked either in beef dripping (in the North of England and Scotland) or lard. Much healthier! Alansplodge (talk) 22:50, 23 January 2022 (UTC)
 * In the era of typesetting, the printing press probably contained heavy metals like lead, and could transfer some to the paper. Nowadays these methods are not so common. Also Phthalocyanine Blue BN a common blue pigment contains copper. Copper is an essential metal for plants. Graeme Bartlett (talk) 22:20, 23 January 2022 (UTC)