Talk:Absolute zero

Absolute zero was nominated as a Natural sciences good article, but it did not meet the good article criteria at the time (December 4, 2022, reviewed version). There are suggestions on the review page for improving the article. If you can improve it, please do; it may then be renominated.

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Move discussion in progress

There is a move discussion in progress on Talk:Absolute Zero (disambiguation) which affects this page. Please participate on that page and not in this talk page section. Thank you. —RMCD bot 09:01, 11 September 2019 (UTC)[reply]

Very low temperatures.

In this section, the first point says:

The current world record was set in 1999 at 100 picokelvins (pK), or 0.0000000001 of a kelvin, by cooling the nuclear spins in a piece of rhodium metal.

But by the bullet points below that one, this is clearly no longer the case, right? Take e.g. the last bullet point:

[...] In a space-based laboratory, temperatures as low as 10 picokelvin ( 10 − 12 {\displaystyle 10^{-12}} 10^{-12} K) temperatures have been achieved, [...]

Well, according to this source: https://www.ctvnews.ca/sci-tech/scientists-create-coldest-temperature-ever-in-a-lab-to-help-understand-quantum-mechanics-1.5632054 (and among many others) say that in 2021 the record was 38 trillionths above -273.15C. So, we should make a change on that. — Preceding unsigned comment added by 2601:5C7:4100:3600:259F:CC85:5F10:EECE (talk) 19:17, 25 November 2022 (UTC)[reply]

In Fact, I already have attempted to include this in past edits but admin editors scrapped it away. If nobody agrees to the proposal here I will just put it forward myself.

Absolute Zero and Degrees of Freedom

What is the difference between a temperature of 0 and the minimum kinetic energy as detailed in the discoeries section in 2000. What are the degrees of freedom in addition to nuclear spin? Which degree of fredom is easiset to constrain? ScientistBuilder (talk) 18:53, 8 February 2022 (UTC) What could be done to generate a state with no degrees of freedom in not just one but however many degrees of freedom there? ScientistBuilder (talk) 18:56, 8 February 2022 (UTC) What is the difference between temperature and energy and what quantum mechanical expresses related the temperature to the amounts of energy due to nuclear spin and other factors. What are the other factors besides quantum spin that contribute to the energy of the Bose-Einstein condensate?ScientistBuilder (talk) 18:58, 8 February 2022 (UTC) How much energy does it take to asymptotically reach a temperature of zero Kelvin? For example what is the difference in energy required to cool helium from 1 degree to 0.9 degree to 0.2 degrees to 0.1 degrees? I am also wondering if there should be a distinction between thermodynamic absolute zero in one degree of freedom and absolute zero in all degrees of freedom?[reply]

]ScientistBuilder (talk) 19:01, 8 February 2022 (UTC)[reply]

History

According to this link The Challenge of Discovering Absolute Zero or -273.15 Degrees Celsius, the now official value of 0 °K = -273.15°C was first determined by Masao Kinoshita and Jiro Oishi of Tokyo Tech, Japan in 1938, and their result was finally recognised by the Consultative Committee for Thermometry of the International Committee for Weights and Measures in 1952. The article includes additional information on how the temperature of absolute zero was determined, citing also work in the USA and Germany. I think use of the information in this article would be a useful addition to the History section. As I am neither a Wikipedia editor nor an expert on this subject, I leave it to others to edit the actual page section. --195.213.152.87 (talk) 12:51, 22 June 2022 (UTC)dww (N.B. I am not former user Dww, but I've used dww as my Id on the internet since 1981, including in email, on Usenet and DMOZ.)[reply]

William Francis Giauque

I was curious why William Francis Giauque is not featured anywhere in this article? 1949 Nobel laureate recognized for his studies in the properties of matter at temperatures close to absolute zero. — Preceding unsigned comment added by 142.113.219.114 (talk) 15:50, 30 November 2022 (UTC)[reply]

GA Review

Unsuccessful. Etrius ( Us) 00:44, 4 December 2022 (UTC)[reply]

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

This review is transcluded from Talk:Absolute zero/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Etriusus (talk · contribs) 22:38, 3 December 2022 (UTC)[reply]

I'll take on this review. Comments out in a bit. Etrius ( Us) 22:38, 3 December 2022 (UTC)[reply]

Nominating editor User:2601:5C7:4100:3600:C39:F9A1:8445:4279 is currently blocked. User has only one edit, which appears to be an incorrect attempt to elevate this page it GA status without review.

Page is missing more citations than it has, multiple maintenance tags. Obvious drive-by nomination, page quickfails. Etrius ( Us) 00:28, 4 December 2022 (UTC)[reply]

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Redefinition of the Kelvin

Perhaps a small section on the 2019 redefinition of the Kelvin scale is in order? it is no longer defined by the triple point of water, rather by the boltzmann constant. 137.248.1.6 (talk) 13:19, 25 September 2023 (UTC)[reply]

This article is not about the kelvin, and it doesn't mention the triple point of water, except in "see also" and in one note. I think it would be fine to edit the note to remove that mention; it was probably never appropriate anyway. --Trovatore (talk) 20:11, 25 September 2023 (UTC)[reply]

Done I got rid of the note, replaced it with a quote from the current SI brochure. Mathnerd314159 (talk) 23:03, 25 September 2023 (UTC)[reply]

Thanks! --Trovatore (talk) 01:35, 26 September 2023 (UTC)[reply]

Introduction

There are some vague ideas in the introduction that hint at physics beyond the standard thermodynamics. For example:

Absolute zero is the coldest point on the thermodynamic temperature scale... Suggesting that it is only a zero point of a specific scale, not the lowest possible physical temperature?
It is commonly thought of as the lowest temperature possible... Hinting that perhaps the common thought is not correct?
The laws of thermodynamics show that absolute zero cannot be reached using only thermodynamic means... Are there some non-thermodynamic means to reach the zero?

Also, zero-point motion does not have to be discussed multiple times in the introduction. Perhaps no original research was intended here, and it's just careless writing. In any case, the introduction should be improved. Jähmefyysikko (talk) 04:26, 1 June 2025 (UTC)[reply]

Reference of "Thermal Motion" - links to kinetic theory of gases

In the introduction. The second paragraph begins with "At Absolute Zero, there is no Thermal motion." With thermal motion linking to kinetic theory of gases. However, there is no use of the phrase thermal motion in the entire article for kinetic theory of gases. I think the concept of thermal motion vs other types of motion needs to be more readily clarified for a reader to understand absolute zero. Maybe not on the absolute zero page itself. Thermal motion would then link to that instead of just the kinetic theory of gases. I don't have an answer for this, I just want to bring up a point that could be improved/clarified by someone more knowledgable. yeaggermiester (talk) 08:53, 9 September 2025 (UTC)[reply]

I think linking to thermal motion in and of itself should be fine; the problem is that it's a redirect that doesn't point to a terribly useful place for the purposes of this article. The reason that it doesn't point to a useful place is that "thermal motion" and "kinetic theory of gases" are not synonymous.

The "correct" fix should be to retarget the redirect to an article or section of article that is actually about thermal motion in general, and not just about the kinetic theory of gases. I don't know whether such a target exists. It seems to be a fairly difficult conceptual problem to prise out conceptually just what part of molecular/atomic/subatomic motion is "thermal" versus the part that's not. An article that actually covers that well would be a huge service. --Trovatore (talk) 22:35, 9 September 2025 (UTC) Now that I read more closely what you wrote, it seems like I mostly just repeated what you said :-( __Trovatore (talk) 22:38, 9 September 2025 (UTC) [reply]

I've just deleted that sentence - the premise is flawed. It starts "At absolute zero", but in the next paragraph, we learn "absolute zero... cannot be reached" - it is an impossible state. One might as well say, "when hell freezes over, there is no thermal motion". The theme of thermal motion is not elaborated on in the rest of the article, as would be expected for a summary-style lead. And of course 0 sources. So there's just nothing there that's worth keeping. Mathnerd314159 (talk) 19:46, 10 September 2025 (UTC)[reply]

that being said though, expanding the zero-point energy section into something discussing how the kinetic theory of gases model breaks down would actually make the article a lot more approachable. Mathnerd314159 (talk) 19:54, 10 September 2025 (UTC)[reply]

No, Mathnerd314159, I'm afraid I really don't agree with you on this point. Certainly there are difficult issues in interpreting counterfactuals in general, but this one is pretty solid. It's not at all impossible for matter to be at absolute zero; it's just impossible to get there by thermodynamic means. And there's nothing ambiguous about the physics in that case. We should be able to address that physics without bringing up pedantic anti-counterfactual arguments. --Trovatore (talk) 20:17, 10 September 2025 (UTC)[reply]

Citations needed. Any editor who adds or restores material has the WP:BURDEN of proving it. Particularly, you've claimed that it's not impossible for matter to be at absolute zero. I highly doubt there is any source that shows that, seeing as the cited material states the lowest temperatures achieved have been the pico kelvins. Mathnerd314159 (talk) 21:25, 10 September 2025 (UTC)[reply]

There is no need to prove that it is possible for matter to be at absolute zero. Maybe I shouldn't have mentioned that, as it seems to be inviting a digression. We do have to establish what would happen if it were at absolute zero, but this is just straightforward application of physics. As for "what would happen if it were", this is just ordinary English; we don't have to delve into philosophical quibbles about the meaning of counterfactuals. --Trovatore (talk) 00:15, 11 September 2025 (UTC)[reply]

You still haven't provided a source, either for whatever phrasing you propose or for the "At absolute zero, there is no thermal motion" statement currently in the article. This statement is meaningless because the whole notion of "thermal motion" has no meaning for systems close to absolute zero. As this article says, "Entropy, or disorder ... only makes sense for a group of particles. When we are dealing with a quantum system... it is far less clear what “entropy” or “temperature” means." So you have a few hours and then I'm going to delete it again because it's unsourced. Mathnerd314159 (talk) 00:43, 11 September 2025 (UTC)[reply]

Actually maybe I kind of agree with you on that one. I'm not really sure what "thermal motion" is. I've tried to get a handle on it and never completely successfully. However we can and should still point out that zero-point motion would persist even at absolute zero. I'm sure that's sourceable, probably even with the counterfactual, but I have zero patience with people arguing against a wording just because it's counterfactual. --Trovatore (talk) 01:00, 11 September 2025 (UTC)[reply]

well that's in the zero point energy section, actually it already has a source. That source says "the ground state is a minimum uncertainty state", "nature keeps the ground-state energy as small as possible... [but] chooses a tradeoff in which the particle has both nonzero [position uncertainty] as well as a nonzero [momentum uncertainty], and therefore nonzero energy". But it doesn't talk about temperature - we have though in the discussions of ground state and Third law of thermodynamics that the ground state is also the state of temperature being absolute zero. This notion of 0 K = ground state seems very "folk physics"-y, so it's still one of those situations where clearer references would be nice, but I'm not going to try to argue that the ZPE section is unverifiable. The statement in the lead though, here's a source:

absolute zero, at which the thermal motion of atoms and molecules reaches its minimum - classically, this would be a state of motionlessness, but quantum uncertainty dictates that the particles still possess a finite zero-point energy

This fundamentally contradicts that the particles have "no" motion.

I'll agree though that this has shifted the counterfactual aspect, it's not so much that absolute zero is impossible therefore has no properties, as that it is "theoretically possible" but that the consensus working theory is now quantum mechanics with a temperature notion based on uncertainty/information/entropy, rather than purely classical mechanics, and therefore naive extrapolations of its properties from classical mechanics are not correct. Mathnerd314159 (talk) 18:30, 11 September 2025 (UTC)[reply]

Here's a good source though, he critiques absolute zero authors on multiple grounds: [1] would be good to add Mathnerd314159 (talk) 18:36, 11 September 2025 (UTC)[reply]

That's WP:FRINGE and WP:SELFPUB. No thanks. Jähmefyysikko (talk) 21:02, 11 September 2025 (UTC)[reply]

I think it would be a fun argument on WP:RSN as to whether he is a subject matter expert. And in this case I couldn't find any other secondary sources, they are all primary (textbooks with no citations). Mathnerd314159 (talk) 21:42, 11 September 2025 (UTC)[reply]

Textbooks are usually fine, they are widely used in physics articles in Wikipedia. Check some physics articles that have been selected Good articles and see what kind of sources are used in those. Jähmefyysikko (talk) 23:07, 11 September 2025 (UTC)[reply]

I looked; there are (1) biographies (already in the history section, not relevant here), (2) BIPM / SI related (not relevant as the standard doesn't define it) (3) historical sources (not relevant b/c it was impossible to get close to absolute zero until relatively recently) (4) recent science papers (like [2])) - they do discuss thermal motion, but not the philosophical issues with the concept of absolute zero. (5) press releases (we have those for the records, not relevant here) (6) science encyclopedias (same issue as the science papers, they have short entries like "it is 0 K"). I guess that's how you get a page like M-theory with zero discussion of issues with the theory beyond "G2 manifolds are still poorly understood mathematically", because even sourcing a neutral statement like "a complete mathematical formulation of M-theory is not known" (lead in Introduction to M-theory) is too difficult. Finding a critical source that actually criticizes the concept on philosophical grounds... these kinds of sources are not going to have that. IDK, seems like one of those WP:IGNOREALLRULES situations. Mathnerd314159 (talk) 02:23, 12 September 2025 (UTC)[reply]

For typical textbook sourcing, see Quantum mechanics. Why would we need a source that criticizes the concept of absolute zero "on philosophical grounds"? Since such discussion is rare in the literature, we don't need to discuss it here either. Jähmefyysikko (talk) 03:44, 12 September 2025 (UTC)[reply]

The quantum mechanics article has a whole section on Philosophical implications, discussing it at length. It seems to mainly quote biographical material, there is even Feynmann's lectures on physics (a primary, arguably self-published source). In the latter half it gets into citing the Stanford Encyclopedia of Philosophy, which unfortunately doesn't have an article on temperature or absolute zero, just thermodynamics. But it's not rare for there to be conceptual issues, or for people to notice them; e.g. [3] says "Many existing terms related to energy are either poorly defined or ambiguous", "the physical nature [of absolute zero] remains unclear, largely due to the common misconception that temperature directly reflects the average kinetic energy of particles". That's just the one I was looking at, there are tons of sources happy to point out this misconception. What's rare is to have someone dedicate a entire chapter to absolute zero, working out what it actually means, as in the source. Considering the lack of informative sources, we could almost consider deleting it as non-notable due to all the sources being passing mentions... Mathnerd314159 (talk) 06:18, 12 September 2025 (UTC)[reply]

Again, a fringe source. Taking Absolute zero to AfD would be absurd and a waste of time. Jähmefyysikko (talk) 06:23, 12 September 2025 (UTC)[reply]

Google Books search for vibrations "zero-point" thermal gives relevant references. For example:

Landau, Akhiezer, Lifshitz (1967) General physics
Sharon Ann Holgate (2021) Understanding Solid State Physics, 2nd ed.

Jähmefyysikko (talk) 05:51, 12 September 2025 (UTC)[reply]