Talk:Negative temperature

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Contents 1 (sic) 2 Accuracy and clarity concerns 3 Name of article 4 new comment 5 Possible copyright infridgement 6 new reference

[edit] (sic)

The second sentence of the article goes as follows:

A system with a negative temperature is not colder than absolute zero, but rather it is, in a sense, hotter than infinite temperature (sic).

It is not clear what the "(sic)" at the end is supposed to mean, it doesn't seem to fit.

In written language, the abbreviation (sic) stands for the latin 'sicut'. It is used when for example a quote containing a spelling mistake is an exact copy of the original. By adding the warning '(sic)', the following signal is given to the reader: "Reader, this spelling mistake is not mine, this quote is copied to the letter."

Sometimes the signal '(sic)' is given when the quote is a statement that looks preposterous. Then '(sic)' signals to the reader: "Reader, it may be hard to beleive that this is a true quote, but it really is a verbatim quote.

Here, '(sic)' is used, but here the context does not involve quoting somebody else. Here the '(sic)' just seems to say: "Now isn't that a whopping surprise?"
--Cleon Teunissen | Talk 23:09, 25 July 2005 (UTC)

I've remove the (sic), because this is not being used in the context of a quote. If readers are going to find this implausible, this can be acknowledged in full prose and then elucidated until it is believable. -- Beland 07:09, 14 August 2005 (UTC)

[edit] Accuracy and clarity concerns

Ow...reading this article always makes my brain hurt. The section "Heat and molecular energy distribution" and the other sections seem to be discussing two different notions of negative temperature. The first distinguishes between different infinite temperatures, and the second is an artifact of accounting for different components of kinetic energy separately.

The first type of negative temperature is rather poorly explained, using apparently contradictory language. ("hotter than infinite"?) I'm worried that it's just plain incorrect. In any case, it needs to be explained a lot better.

It should also be explained that in no circumstances should any object or system have a negative kinetic energy, if indeed that's the case.

The cleanup-verify tag isn't exactly right, but you get the idea. I don't have the referenced book handy; if someone who does can check it and see whether or not it supports any of this article, that would be helpful. -- Beland 07:38, 14 August 2005 (UTC)

This isn't well-written, but the content seems correct. I don't have Kittel with me at home, but the context jives with what I remember. Salsb 23:04, August 15, 2005 (UTC)

The article is quite correct, but not very didactical. The "hotter than infinite temperature" remark is technically correct but not very useful. It would be equally correct, and perhaps more helpful, to say, "If a negative temperature system comes into contact with a positive-temperature system, heat will always flow from the negative temperature system to the positive temperature system. In this sense, a system at negative temperature is hotter than any sysetm at positive temperature." 130.89.204.173 18:40, 25 October 2005 (UTC)

This whole discussion needs to be much clearer. Since we are discussing the states of particles around a nucleus, the discussion needs to unambigously state that the notion of "negative temperature" is more realisically "energies lower than you can get just by cooling things down". If there were an article on "quantum thermodynamics", much of the discussion would go there.

Nothing that I see here is inherently wrong other than the "hotter than infinite". Remember that division by zero is not defined; it does not equal infinity. S Schaffter 22:08, 22 January 2006 (UTC)

Riemann sphere much? Melchoir 01:11, 11 February 2006 (UTC)

[edit] Name of article

Thanks to GregGWood for making the redirect here to fulfill my requested article, negative absolute temperature. It hadn't occurred to me to search under this simpler name.

But I wonder if it's really a very good name. To physicists I suppose "negative temperature" is unambiguous, but to the layman, a temperature below the zero of whatever scale he's used to might be called a negative temperature. There's not even a mention of this linguistic possibility in the lead section. Not that I'm saying there should be (I can't think of a wording that's not just plain ugly), but if the article were at negative absolute temperature (with a redirect from negative temperature) it should head off such a possible confusion. --Trovatore 23:00, 16 March 2006 (UTC)

Hmm... I think "Negative temperature" is okay. If you Google ("negative temperature" -coefficient), I'd estimate only about 10% of hits are talking about subzero temperatures on some scale, so there doesn't seem to be a discrepancy with common usage. Conversely, that search gets 245,000 hits, while inserting "absolute" gets just 252, so "negative temperature" really is the more common name for the concept.

Regardless of its name, what this article could use is an explicit explanation at the top that this article is talking about a qualitative difference in temperature, not a numerical artifact of a scale like Celsius. Melchoir 23:24, 16 March 2006 (UTC)

As long as you can do it without using the words "this article" or similar "metalanguage". I really dislike that. If an article describes the content well enough, it shouldn't have to describe itself. --Trovatore 23:46, 16 March 2006 (UTC)

Indeed. Let's see... Melchoir 23:58, 16 March 2006 (UTC)

Nice job! --Trovatore 00:35, 17 March 2006 (UTC)

[edit] new comment

I'm reverting this article, to see if it has been vandlised--WngLdr34 23:40, 18 November 2006 (UTC)

Sorry, WngLdr34, but I can't make out what you mean. You don't seem to have edited the article. By the way, new comments on talk pages should go to the bottom of the page. Welcome to WP! --Trovatore 22:28, 19 November 2006 (UTC)

I think I know what he means: Negative Temperature doesn´t exists. Temperature is only defined in equilibrium states and all the examples just look like Negative Temperature if you just watch a small aspect of the system whitch is not in equilibrium with the rest of the system.

You could try the same complaint about positive temperatures, especially in the theory of heat flow, which relies upon the concept of temperature gradients. A small system does not have to be in equilibrium with "the rest of the system" -- its surroundings -- to have a meaningful temperature. Its internal relaxation time must simply be shorter than its relaxation time due to external heat transfer. This physical, quantitative criterion has been experimentally verified in many nuclear spin systems. They really are sufficiently isolated from their lattices to have their own temperatures, and sometimes these are negative.

Granted, the article doesn't explain all this, but it will when I work up the energy. Melchoir 18:48, 29 November 2006 (UTC)

[edit] Possible copyright infridgement

Unless i am mistaken, the text refers to page number 462 of 'Thermal Physics'. I quote from paragraph "Heat and molecular energy distribution":

As Kittel and Kroemer (p.462) put it, "The temperature scale from cold to hot runs +0 K, . . . , +300 K, . . . , +∞ K, −∞ K, . . . , −300 K, . . . , −0 K."

Looks like it is referring to this (non-public, but commercial) book: (first one mentioned in the references)

• Kittel, Charles and Herbert Kroemer (1980). Thermal Physics (2nd ed.). W. H. Freeman Company. ISBN 0-7167-1088-9. 

Note: I am not experienced regarding contributing to wikipedia, please excuse me if i did something wrong. I will not take action and remove that part of the text myself, please doublecheck my findings.

83.98.234.114 09:50, 14 December 2006 (UTC)

You're allowed (even encouraged) to quote from reference materials, even if they're copyright. This has nothing to do with Wikipedia per se; it's a general rule. The borderline where citation becomes infringement is fuzzy and ill-defined, but one brief sentence out of a whole book isn't even on the radar screen. See fair use for more info. --Trovatore 17:41, 14 December 2006 (UTC)

[edit] new reference

you all should take a look at this site

http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/neg_temperature.html

it has more stuff about negative temperature, although i don't know how to add references, all i do on wikipedia is suggest things and edit grammar ;) —The preceding unsigned comment was added by 68.188.54.173 (talk) 04:11, 18 February 2007 (UTC).