User:Jmkinder1/sandbox

=Possible Articles=

Arctic Circle
In Arctic circle there are conflicting definitions of sunrise and sunset, and hence, of the location of the Arctic Circle. One part of the article says polar night is when the sun sets below the horizon and does not rise again for 24 hours or more, while another says it is when the center of the sun does not dip below the horizon. One of the references on "polar night" seems to give proper astronomical definitions, but the article could use more primary sources.

It seems this is the offending statement:

The Arctic Circle marks the southernmost latitude at which, on the December solstice, the shortest day of the year in the northern hemisphere, the sun will not rise all day, and on the June solstice, the longest day of the year in the northern hemisphere, the sun will not set.

According to Ref. 2, the Arctic Circle is where the center of the sun meets the horizon on these days — not where is "does not rise" or "does not set". Ref. 2 is a secondary source. It would be nice to have a definition from a primary source, like the International Astronomers Union or the National Geographic Society instead.

The next statement is false, according to Ref. 2:

These phenomena are referred to as polar night and midnight sun respectively,

The definition of polar night refers to civil twilight, not sunset, and polar night is not experienced at the Arctic circle.

Moreover, in Polar night, there is a statement that requires clarification:

''"Night" is understood as the center of the Sun being below a free horizon. Since the atmosphere refracts sunlight, the polar day is longer than the polar night, and the area that is affected by polar night is somewhat smaller than the area of midnight sun. The polar circle is located at a latitude between these two areas, at approximately 66.5°. While it is day in the Arctic Circle, it is night in the Antarctic Circle, and vice versa.''

The author has subjectively defined "night" in contradiction to common sense and other sources.

Atom chip
The Wikipedia article on "atom chip" refers to an Intel processor. However, an "atom chip" is also the name of a MEMS device used to manipulate Bose-Einstein condensates in cold atom physics, as described here: https://www.imperial.ac.uk/centre-for-cold-matter/research/cold-atoms/interferometer/.

This technology was part of a recent experiment that achieved an incredibly low temperature of 38 pK, as described here (https://physics.aps.org/articles/v14/119?utm_campaign=weekly&utm_medium=email&utm_source=emailalert) and in the accompanying Physical Review Letters.

It seems like a new page should be created for the "atom chip" of cold atom physics and a disambiguation page should be created for "atom chip".

Many-body problem
This article on the quantum many body problem needs a more descriptive lead. It has a lot of references and resources, but it does not orient the reader to the problem or explain much about it. Jmkinder1 (talk) 19:52, 9 February 2021 (UTC)

Matrix Product States
Another article that could use improvement is the one on matrix product states. It is related to tensor networks, and it needs a lot of work. I have extensive sources for this article already.

Jmkinder1 (talk) 07:43, 25 January 2021 (UTC)

Hubbard Model
One article I will edit is The Hubbard Model. I like the topic, know a bit about it, and the article seems only partially formed. A connection to quantum science might be recent atomic lattice simulations of the model, and the use of quantum annealing to solve it.

Jmkinder1 (talk) 06:36, 17 January 2021 (UTC)

Tensor Network
Another article I will edit is on tensor network states. The page does not exist! With all of their use in quantum information and quantum computing, I find this surprising. Jmkinder1 (talk) 10:08, 19 January 2021 (UTC)

I created a draft page in my sandbox.
 * It has sense been moved to the main space: Tensor network.

Jmkinder1 (talk) 19:55, 9 February 2021 (UTC)

From "Quantum Tensor Networks in a Nutshell" ...


 * 1) Tensor network state is a multilinear ansatz --- linear in each variational parameter.
 * 2) Deutsch and Feynman used tensor network notation in describing quantum circuits and quantum computers.
 * 3) Varieties of tensor networks
 * 4) * matrix product states
 * 5) * tensor trains (different than MPS?)
 * 6) * snake states
 * 7) * tree tensor networks
 * 8) * multiscale entanglement renormalization ansatz
 * 9) * projected entangled pair states
 * 10) * correlator product states (equivalent to neural network quantum states )

Degrees of freedom (physics and chemistry)
There is a contradiction between the text and a table in Degrees of freedom (physics and chemistry). It seems the confusion comes from kinetic degrees of freedom versus total degrees of freedom. There is a lot of material in the talk page, and it looks like a heated (but uninformed) dispute. I think it would be helpful to clean up the discussion — or at least eliminate the contradiction.

The article on the Equipartition theorem seems better written and less contentious. Perhaps it would be wise to draw from this article in improving the other.

Piezoresistive effect
The page on the Piezoresistive effect is seriously lacking in citations, and it seems the mathematical notation is not consistent throughout.

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