The Kohn-Luttinger Effect in Gauge Theories

Abstract

Kohn and Luttinger showed that a many body system of fermions interacting via short range forces becomes superfluid even if the interaction is repulsive in all partial waves. In gauge theories such as QCD the interaction between fermions is long range and the assumptions of Kohn and Luttinger are not satisfied. We show that in a U(1) gauge theory the Kohn-Luttinger phenomenon does not take place. In QCD attractive channels always exist, but there are cases in which the primary pairing channel leaves some fermions ungapped. As an example we consider the unpaired fermion in the 2SC phase of QCD with two flavors. We show that it acquires a very small gap via a mechanism analogous to the Kohn-Luttinger effect. The gap is too small to be phenomenologically relevant.

5 pages, 2 figure, minor revisions, to appear in PRD

References in corpus (1)

• Induced P-wave Superfluidity in Asymmetric Fermi Gases

Cited by in corpus (4)

• Spin-triplet pairing instability of the spinon Fermi surface in a U(1) spin liquid
• Gapless Surfaces in Anisotropic Superfluids
• Renormalization-group approach to the Kohn-Luttinger superconductivity: Amplification of the pairing gap from ${\ell }^4$ to $\ell$
• The Kohn-Luttinger Effect in Dense Matter and its Implications for Neutron Stars