Evolution of the dynamics of neutral superconductors between BCS and BEC regimes: The variational approach

Andrey V. Chubukov; Dmitry Mozyrsky

doi:10.1063/1.5037555

Evolution of the dynamics of neutral superconductors between BCS and BEC regimes: The variational approach

Andrey V. Chubukov, Dmitry Mozyrsky

Physics and Astronomy (Twin Cities)

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2 Scopus citations

Abstract

We use variational approach to analyze the evolution of the dynamics of a neutral s-wave superconductor between BCS and BEC regimes. We consider 2D case, when BCS-BEC crossover occurs already at weak coupling and is governed by the ratio of the two scales - the Fermi energy E_F and the bound state energy for two fermions in a vacuum, E₀. BCS and BEC regimes correspond to E_F ≥ E₀ and E_F ≤ E₀, respectively. We compute the spectrum of low-energy bosonic excitations and show that the velocity of phase fluctuations remains v F / 2 through BCS-BEC crossover. We also discuss the topological A φ term in the effective action.

Original language	English (US)
Pages (from-to)	528-533
Number of pages	6
Journal	Fizika Nizkikh Temperatur
Volume	44
Issue number	6
DOIs	https://doi.org/10.1063/1.5037555
State	Published - Jun 1 2018

Bibliographical note

Funding Information:
We thank I. Aleiner, J. J. Dziarmaga, I. Martin, M. Stone, J. Sauls, D. Solenov, and G. E. Volovik for valuable discussions. The work at Los Alamos was performed under the auspices of the United States Department of Energy under Contract No. DE5AC52-06NA25396 and supported by LDRD and BES Grant Nos. 20170460ER and E3B7, respectively. The work by AVC was supported by the Office of Basic Energy Sciences U.S. Department of Energy under Award No. DE-SC0014402. A.V.C. is thankful to KITP at UCSB, where part of the work has been done. KITP is supported by NSF Grant No. PHY-1125915.

Funding Information:
The work at Los Alamos was performed under the auspices of the United States Department of Energy under Contract No. DE5AC52-06NA25396 and supported by LDRD and BES Grant Nos. 20170460ER and E3B7, respectively. The work by AVC was supported by the Office of Basic Energy Sciences U.S. Department of Energy under Award No. DE-SC0014402.

Publisher Copyright:
© 2018 Author(s).

Keywords

Berry phase
S-wave
Superconductor

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abstract = "We use variational approach to analyze the evolution of the dynamics of a neutral s-wave superconductor between BCS and BEC regimes. We consider 2D case, when BCS-BEC crossover occurs already at weak coupling and is governed by the ratio of the two scales - the Fermi energy EF and the bound state energy for two fermions in a vacuum, E0. BCS and BEC regimes correspond to EF ≥ E0 and EF ≤ E0, respectively. We compute the spectrum of low-energy bosonic excitations and show that the velocity of phase fluctuations remains v F / 2 through BCS-BEC crossover. We also discuss the topological A φ term in the effective action.",

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Evolution of the dynamics of neutral superconductors between BCS and BEC regimes: The variational approach

Abstract

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