SU(2) Ginzburg-Landau theory for degenerate Fermi gases with synthetic non-Abelian gauge fields

TL;DR

This paper develops an SU(2) Ginzburg-Landau theory to describe degenerate Fermi gases with synthetic non-Abelian gauge fields, revealing how these fields influence superfluid properties and predicting a new non-Abelian Josephson effect.

Contribution

It introduces the first SU(2) Ginzburg-Landau equations for such systems, linking gauge field strength to critical temperature changes and proposing a novel Josephson effect.

Findings

Superfluid critical temperature varies linearly with gauge field strength.

Predicted a new SU(2) non-Abelian Josephson effect.

Established a gauge-field theory for pairing fields without electric charge.

Abstract

The non-Abelian gauge fields play a key role in achieving novel quantum phenomena in condensed-matter and high-energy physics. Recently, the synthetic non-Abelian gauge fields have been created in the neutral degenerate Fermi gases, and moreover, generate many exotic effects. All the previous predictions can be well understood by the microscopic Bardeen-Cooper-Schrieffer theory. In this work, we establish an SU(2) Ginzburg-Landau theory for degenerate Fermi gases with the synthetic non-Abelian gauge fields. We firstly address a fundamental problem how the non-Abelian gauge fields, imposing originally on the Fermi atoms, affect the pairing field with no extra electric charge by a local gauge-field theory,and then obtain the first and second SU(2) Ginzburg-Landau equations. Based on these obtained SU(2) Ginzburg-Landau equations, we find that the superfluid critical temperature of the intra- (inter-) band pairing increases (decreases) linearly, when increasing the strength of the synthetic non-Abelian gauge fields. More importantly, we predict a novel SU(2) non-Abelian Josephson effect, which can be used to design a new atomic superconducting quantum interference device.