Timeline for Why are there no Goldstone modes in superconductor?
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| yesterday | comment | added | cx1114 | So intuitively imagine cool down an atomic fermi gas to be a superfluid, and then we may observe some sound wave propagation. Now we cool down a piece of metal to undergo a BCS, but appliying no fields to excite current. Then why there will not be gapless modes as in the netral fermi superfluid case? | |
| yesterday | comment | added | cx1114 | The sound/phase modes being pushed up to plasma frequency seem to be deduced from applying an external field, as Anderson in his paper already pointed out. But if the fields are to fluctuate quantum mechanically, and no external field is applied. How would the argument go? | |
| yesterday | comment | added | mike stone | The question of the difference between charged and neutral superfluids is just one of classical electrodynamics. Any charged compressible fluid, super or normal, has its sound modes pushed up to above the plasma-frequency gap. In addition, for a superfluid of charge $e$ particles you have the London relation $m{\boldsymbol \omega}+ e {\bf B}=0$ and plugging this into Maxwell gives you the Meissner effect as well. BCS is not involved. | |
| yesterday | comment | added | cx1114 | But the question is really about why the same BCS Hamiltonian (by BCS I mean a non-relativistic electron system with an attractive quartic interaction ) used to describe a neautral fermi system undergoing BCS transition and a charged system has different spectrum in the 2 cases. | |
| Jun 28 at 15:41 | history | answered | mike stone | CC BY-SA 4.0 |