Questions tagged [low-temperature-physics]
89 questions
48
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5 answers
Why is Helium so hard to liquify?
By the end of the 19th century all gasses had been liquefied apart from helium (He). What is it about helium that makes it so hard to liquefy compared to the other gases? And why does it need to be pre cooled in the Joule-Kelvin expansion?
34
votes
2 answers
What is the largest number of bosons placed in a BEC?
What is the record for the largest number of bosons placed in a Bose-Einstein condensate?
What are the prospects for how high this might get in the future?
EDIT: These guys reported 20 million atoms in 2008. "Large atom number Bose-Einstein…
Jess Riedel
- 3,764
28
votes
4 answers
Are room temperature superconductors theoretically possible, and through what mechanism?
At the moment, the highest critical temperature superconductor known to science (or myself, at least) is mercury barium calcium copper oxide. With a $T_{c}$ of roughly 133 K, that's well above the boiling point of nitrogen, and even well above the…
TheEnvironmentalist
- 2,794
27
votes
3 answers
What is cold wind?
As per my understanding, temperature is the movement of particles in an environment. A highly energetic environment where particles possess high energy has a high temperature,
and low energy means low temperature.
Wind in general means speed and…
Vishwa Mithra Tatta
- 507
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14
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2 answers
How are LIGO mirrors cooled?
The recent LIGO announcement Observation of Gravitational Waves from a Binary Black Hole Merger has some technical details about LIGO. For example,
LIGO is a modified Michelson interferometer. The test masses are 40 kg fused silica mirrors that…
mmesser314
- 49,702
12
votes
1 answer
Is there a database or a classification of High-temperature superconductors?
I was wondering if there exists a list with all (or most of) the High-$T_c$ superconductor materials.
In particular I'd like to know if there are databases or review that classifies them by their electronic/doping structure or some other different…
DDd
- 351
10
votes
2 answers
Why is chemical potential, μ=0 when calculating critical temperature of BECs?
How do we justify taking the chemical potential, $\mu$ as $0$ when calculating the critical temperature of Bose-Einstein Condensates (BECs)?
I apologise as I do not how to use LaTeX, for if I did the elegance of mathematics would’ve allowed me to…
RamanSB
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8
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4 answers
Can low temperature plasma exist?
Plasma is ionized gas which as far as I know only occurs at high temperatures. When plasma cools down it tends to recombine with the electrons present and turn back into gas. But what if the disassociated electrons in the plasma were removed and the…
Loourr
- 958
7
votes
0 answers
How extremely low temperatures (near absolute zero) are actually measured
How do the industrial or laboratory thermometers for this purpose work like:
what effects are based on, what are other alternatives
how accurate they all are
6
votes
1 answer
The Correct Statement of the Third Law of Thermodynamics
The Third Law of Thermodynamics can be stated in various ways, one of which is:
The entropy of a perfect crystal at absolute zero is exactly equal to
zero.
Is this true for only "perfect crystals" and not for (say) fluids?
noir1993
- 2,226
6
votes
2 answers
1D superconductivity does not exist even at zero temperature?
In class Professor claimed that 1D superconductivity does not exist even at zero temperature. I did a preliminary search and found papers on 1D superconductors. Did I or the Prof make a mistake or could somebody point to me a proof to this claim…
PhysicsMath
- 361
5
votes
1 answer
Is there any other superfluid element except helium?
Is there any other superfluid element except helium?
Everywhere we see and speak about superfluidity, we just speak about superfluid helium. but is't there any other element or material or system which acts as a superfluid?
P.A.M
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4
votes
0 answers
What happens to isothermal compressibility at zero temperature?
In chapter 11 of his book on thermodynamics, Callen states that Nernst postulate implies the isothermal compressibility (denoted as $\kappa_T$) of any system vanishes as its temperature approaches zero, though this statement is not justified in the…
Tofi
- 2,699
4
votes
2 answers
Can a permanent magnetic become too cold to function?
I have heard that it's possible for a permanent magnet to become too hot to function, especially if it reaches melting temperature however I cannot find much on the affect of cooling a magnet especially to temperatures around absolute zero.
Derek Seabrooke
- 630
4
votes
2 answers
What happens to a liquid nitrogen canister under pressure if left at room temperature? Will it eventually explode? Or forever stay cold?
If I put a strong, sealed container of liquid nitrogen on a table at room temperature, will it always stay cold? Or will it slowly heat up until the canister bursts? Assume it is an extremely strong container made of reinforced materials? I suppose…
hein
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