Only-phase Popov action: thermodynamic derivation and superconducting electrodynamics
Abstract
We provide a thermodynamic derivation of the only-phase Popov action functional, which is often adopted to study the low-energy effective hydrodynamics of a generic nonrelativistic superfluid. It is shown that the crucial assumption is the use of the saddle point approximation after neglecting the quantum-pressure term. As an application, we analyze charged superfluids (superconductors) coupled to the electromagnetic field at zero temperature. Our only-phase and minimally-coupled theory predicts the decay of the electrostatic field inside a superconductor with a characteristic length much smaller than the London penetration depth of the static magnetic field. This result is confirmed also by a relativistic only-phase Popov action we obtain from the Klein-Gordon Lagrangian.
- Publication:
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Journal of Physics A Mathematical General
- Pub Date:
- September 2024
- DOI:
- 10.1088/1751-8121/ad6ab3
- arXiv:
- arXiv:2408.00528
- Bibcode:
- 2024JPhA...57I5302S
- Keywords:
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- superconductors;
- electrodynamics;
- hydrodynamics;
- superfluids;
- Condensed Matter - Quantum Gases;
- Condensed Matter - Superconductivity
- E-Print:
- 13 pages, 0 figures. Published in Journal of Physics A: Mathematical and Theoretical