Questions tagged [superfluidity]

A flow with no viscosity

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10
votes
1answer
336 views

Why is the BCS trial function valid across the BEC-BCS crossover?

In one of the two main theoretical approaches used in describing ultracold Fermi gases and the BEC-BCS crossover, the so-called BCS-Leggett approach, the starting point is the BCS trial wavefunction: ...
7
votes
3answers
93 views

Cosmic background radiation vs superfluids

I've been reading a lot about superfluids lately (fluids that are cooled to such a degree that they no longer obey the standard laws of physics) in various physics journals and realized that the ...
2
votes
1answer
166 views

Limits of superfluidity

Superconductivity has limits of currents and magnetic fields they can endure before dropping the superconductivity phase What are the corresponding limits of superfluidity? what are the limit ...
5
votes
1answer
1k views

Helium-4 superfluidity and gauge symmetry breaking

Is there an accessible account of superfluidity in Helium-4 as a manifestation of "global gauge symmetry" breaking? And what is meant by "global gauge symmetry"? I was taught that gauge symmetries ...
2
votes
1answer
615 views

Complex valued energy

I'm working on a 2D He superfluid system with vortices. I was asked to calculate the kinetic energy of vortex-(anti-)vortex pairs and compare the two situations. One finds in literature that the ...
4
votes
1answer
1k views

Phonons, rotons, and maxons

What are phonons, rotons, and maxons, and what does their dispersion curve have to do with superfluidity? I understand that they are quasiparticles, but I'm not entirely sure what that implies. Are ...