Exotic Pairing Structures in Population-Imbalanced Fermionic Systems: Dynamics as a Probe

TL;DR

This paper explores the dynamics of population-imbalanced fermionic systems with resonant pairing, proposing a method to detect exotic phases through oscillation frequencies induced by external magnetic fields.

Contribution

It introduces a dynamic probing technique using oscillation frequencies to identify exotic pairing states in imbalanced fermionic systems.

Findings

Persistent oscillations in condensate fraction reveal pairing nature.

External magnetic fields can locate oscillation frequencies.

Method enables indirect detection of exotic phases.

Abstract

We investigate a population-imbalanced two-species fermionic system where the resonantly-paired fermions combine to form bosonic molecules via Feshbach interaction. We study the dynamics of the intrinsic quantum fluctuations of the system. It is shown that the natural fluctuations of the condensate fraction consists of a fixed number of periodic components : indicating that these oscillations do not die out, and are sustained in the mean field dynamics of the system. These frequency components bear distinct signatures of the nature of pairing present in the system. We describe how a time dependent external magnetic field can be used to locate these oscillation frequencies, and thus to explore the momentum space structure of the population imbalanced system. We propose that this method can be used as an indirect experimental probe for detecting exotic phases like the breached pair state, FFLO state, and a phase-separated state comprising of BCS and normal regions.