Polar molecules in bilayers with high population imbalance

TL;DR

This paper studies a highly imbalanced bilayer system of polar molecules, analyzing impurity behavior, chemical potential, and momentum relaxation, revealing long-range dipolar interactions and damping effects in such quantum setups.

Contribution

It introduces a detailed theoretical analysis of impurity dynamics and interactions in a bilayer polar molecule system with extreme population imbalance, using perturbation and many-body approaches.

Findings

Calculated impurity chemical potential using perturbation and ladder approximation.

Determined the momentum relaxation rate related to dipolar drag effect.

Linked chemical potential results to collective mode measurements.

Abstract

We investigate a dilute Fermi gas of polar molecules confined into a bilayer setup with dipole moments polarized perpendicular to the layers. In particular, we consider the extreme case of population imbalance, where we have only one particle in one layer and many particles in the other one. The single molecule is attracted by the dilute Fermi-gas through the inter-layer dipole-dipole force presenting an interesting impurity problem with longrange anistropic interaction. We calulate the chemical potential of the impurity, in second order perturbation theory and in ladder approximation with a Brueckner-Hartree-Fock approach. Moreover, we determine the momentum relaxation rate of the impurity, which is related to the "dipolar" drag effect. For a confined system we relate the results for the chemical potential with the measurement of the collective modes of the impurity. The momentum relaxation rate provide instead an estimate on how quickly the oscillations are damped.