Stability conditions and Fermi surface topologies in a superconductor

Abstract

References (38)

Citing Articles

Download: PDF (406 kB) or Buy this Article (US$25) (Use Article Pack)

Elena Gubankova,¹ Andreas Schmitt,^1,2 and Frank Wilczek¹
¹Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
²Department of Physics, Washington University, St Louis, Missouri 63130, USA

Received 29 March 2006; revised 11 July 2006; published 11 August 2006

Candidatehomogeneous, isotropic superfluid or superconducting states of paired fermion specieswith different chemical potentials, can lead to quasiparticle excitation energiesthat vanish at either 0, 1, or 2 spheres inmomentum space. With no zeros, we have a conventional BCSsuperconductor. The other two cases, "gapless" superconductors, appear in mean-field theory for sufficiently large mismatches and/or sufficiently large couplingstrengths. Here we examine several stability criteria for those candidatephases. Positivity of number susceptibility appears to provide the mostpowerful constraint, and renders all the two-zero states that wehave examined mechanically unstable. Our results should apply directly toultracold fermionic atom systems.

URL:	http://link.aps.org/doi/10.1103/PhysRevB.74.064505
DOI:	10.1103/PhysRevB.74.064505
PACS:	03.75.Ss; 11.15.Ex 03.75.Ss Degenerate Fermi gases 11.15.Ex Spontaneous breaking of gauge symmetries YEAR: 2006
KEYWORDS:	Fermi surface, superfluidity, fermion systems, chemical potential, quasiparticles, BCS theory, superconducting materials

REFERENCES (38)

View in Separate Window/Tab

For access to fully linked references, you need to log in. For access to fully linked references, you need to Log in.

J. Bardeen, L. N. Cooper, and J. R. Schrieffer, Phys. Rev. 108, 1175 (1957).
A. J. Leggett, Rev. Mod. Phys. 47, 331 (1975);
M. Sigrist and K. Ueda, Rev. Mod. Phys. 63, 239 (1991).
T. Schäfer, Phys. Rev. D 62, 094007 (2000);

ibid. 71, 054016 (2005)

C.-H. Pao, S.-T. Wu, and S.-K. Yip, Phys. Rev. B 73, 132506 (2006).
E. Gubankova, W. V. Liu, and F. Wilczek, Phys. Rev. Lett. 91, 032001 (2003).
W. V. Liu and F. Wilczek, Phys. Rev. Lett. 90, 047002 (2003).
E. Gubankova, E. G. Mishchenko, and F. Wilczek, Phys. Rev. Lett. 94, 110402 (2005).
C. A. Regal, M. Greiner, and D. S. Jin, Phys. Rev. Lett. 92, 040403 (2004);

ibid. 92, 120401 (2004)

ibid. 92, 120403 (2004)

ibid. 92, 150402 (2004)

ibid. 93, 050401 (2004)

E. Babaev, Phys. Rev. B 63, 184514 (2001).
P. F. Bedaque, H. Caldas, and G. Rupak, Phys. Rev. Lett. 91, 247002 (2003);

ibid. 94, 017001 (2005)

ibid. 95, 060401 (2005)

K. Rajagopal and A. Schmitt, Phys. Rev. D 73, 045003 (2006).
M. Huang and I. A. Shovkovy, Phys. Rev. D 70, 094030 (2004).
K. Fukushima, Phys. Rev. D 72, 074002 (2005).
D. T. Son and M. A. Stephanov, Phys. Rev. A 74, 013614 (2006).
P. Fulde and R. A. Ferrell, Phys. Rev. 135, A550 (1964).
M. G. Alford, J. A. Bowers, and K. Rajagopal, Phys. Rev. D 63, 074016 (2001);
D. E. Sheehy and L. Radzihovsky, Phys. Rev. Lett. 96, 060401 (2006).
L. He, M. Jin, and P. f. Zhuang, Phys. Rev. B 73, 214527 (2006).
A. Bulgac, M. McNeil Forbes, and A. Schwenk, Phys. Rev. Lett. 97, 020402 (2006).
J. M. Cornwall, R. Jackiw, and E. Tomboulis, Phys. Rev. D 10, 2428 (1974).
L. N. He, M. Jin, and P. F. Zhuang, Phys. Rev. B 73, 024511 (2006).
E. V. Gorbar, M. Hashimoto, V. A. Miransky, and I. A. Shovkovy, Phys. Rev. D 73, 111502 (2006).
S.-T. Wu and S.-K. Yip, Phys. Rev. A 67, 053603 (2003).
A. Schmitt, Q. Wang, and D. H. Rischke, Phys. Rev. D 69, 094017 (2004).
A. M. Clogston, Phys. Rev. Lett. 9, 266 (1962);