Pair formation and collapse in imbalanced Fermion populations with unequal masses

TL;DR

This study uses exact Quantum Monte Carlo simulations to investigate how unequal masses affect pair formation and stability in imbalanced Fermionic systems, revealing a tendency toward collapse as mass disparity grows.

Contribution

It provides the first comprehensive analysis of mass imbalance effects on Fermionic pairing and collapse using exact quantum Monte Carlo methods across different interaction types.

Findings

System becomes unstable and collapses with increasing mass difference.

Ground state transitions to an inhomogeneous collapsed phase.

Ensemble choice influences phase stability considerations.

Abstract

We present an exact Quantum Monte Carlo study of the effect of unequal masses on pair formation in Fermionic systems with population imbalance loaded into optical lattices. We have considered three forms of the attractive interaction and find in all cases that the system is unstable and collapses as the mass difference increases and that the ground state becomes an inhomogeneous collapsed state. We also address the question of canonical vs grand canonical ensemble and its role, if any, in stabilizing certain phases.