Bose-representation for a strongly coupled nonequilibrim fermionic superfluid in a time-dependent trap

TL;DR

This paper develops a theoretical framework for describing strongly coupled nonequilibrium fermionic superfluids in time-dependent traps, showing their equivalence to Bose gases and deriving a nonlinear GP equation for the condensate.

Contribution

It introduces a regular functional integral approach to nonequilibrium strongly coupled fermionic systems and connects them to Bose gases and the GP equation.

Findings

Fermionic systems with strong attraction can be described as dilute Bose gases in nonequilibrium.

The nonequilibrium BCS theory reduces to the nonlinear time-dependent Gross-Pitaevski equation.

Provides a unified description of strongly coupled fermionic superfluids in dynamic external potentials.

Abstract

Using the functional integral formulation of a nonequilibrium quantum many-body theory we develop a regular description of a Fermi system with a strong attractive interaction in the presence of an external time-dependent potential. In the strong coupling limit this fermionic system is equivalent to a noequilibrium dilute Bose gas of diatomic molecules. We also consider a nonequilibrim strongly coupled Bardeen-Cooper-Schrieffer (BCS) theory and show that it reduces to the full nonlinear time-dependent Gross-Pitaevski (GP) equation, which determines an evolution of the condensate wave function.