1210.7934 (K. G. Klimenko et al.)

Superconducting phase transitions induced by chemical potential in
(2+1)-dimensional four-fermion quantum field theory    [PDF]

K. G. Klimenko, R. N. Zhokhov, V. Ch. Zhukovsky

In the paper a generalization of the (1+1)-dimensional model by Chodos et al [Phys. Rev. D61, 045011 (2000)] has been performed to the case of (2+1)-dimensional spacetime. The model includes four-fermion interaction both in the fermion-antifermion (or chiral) and fermion-fermion (or superconducting) channels. We study temperature $T$ and chemical potential $\mu$ induced phase transitions in the leading order of large-$N$ expansion technique, where $N$ is a number of fermion fields. It is shown that at sufficiently large values of $\mu$ and arbitrary relations between coupling constants, superconducting phase appears in the system both at T=0 and $T>0$. In particular, at T=0 and sufficiently weak attractive interaction in the chiral channel, the Cooper pairing occurs for arbitrary couplings in the superconducting channel even at infinitesimal values of $\mu$.

View original: http://arxiv.org/abs/1210.7934