Two- and many-body physics of ultracold molecules dressed by dual microwave fields

TL;DR

This paper explores the behavior of ultracold polar molecules dressed with dual microwave fields, identifying optimal conditions for evaporative cooling and analyzing their ground-state properties using theoretical models.

Contribution

It introduces a new dual-microwave dressing scheme, derives an effective interaction potential, and studies the many-body physics of microwave-shielded polar molecules.

Findings

Optimal elastic-to-inelastic scattering ratio identified

Effective interaction potential validated

Ground-state properties show weakly and strongly correlated phases

Abstract

We investigate the two- and many-body physics of the ultracold polar molecules dressed by dual microwaves with distinct polarizations. Using Floquet theory and multichannel scattering calculations, we identify a regime with the largest elastic-to-inelastic scattering ratio which is favorable for performing evaporative cooling. Furthermore, we derive and, subsequently, validate an effective interaction potential that accurately captures the dynamics of microwave-shielded polar molecules (MSPMs). We also explore the ground-state properties of the ultracold gases of MSPMs by computing physical quantities such as gas density, condensate fraction, momentum distribution, and second-order correlation. It is shown that the system supports a weakly correlated expanding gas state and a strongly correlated self-bound gas state. Since the dual-microwave scheme introduces addition control knob and is essential for creating ultracold Bose gases of polar molecules, our work pave the way for studying two- and many-body physics of the ultracold polar molecules dressed by dual microwaves.