Two-photon-assisted collisions in ultracold gases of polar molecules

TL;DR

This paper develops a theoretical framework for understanding two-photon-assisted collisions of ultracold polar molecules, focusing on collisional shielding and the effects of laser parameters on collision rates.

Contribution

It introduces a formalism incorporating laser fields and dipole interactions, applying adiabatic elimination to analyze two-photon collisional shielding in ultracold polar molecules.

Findings

Feasibility of two-photon collisional shielding demonstrated

Laser Rabi frequencies significantly influence collision dynamics

Suppression of spontaneous emission via Raman resonance condition

Abstract

We present a theoretical formalism to treat the ultracold dynamics of a pair of colliding polar molecules submitted to two laser fields. We express the dressed Hamiltonian including the dipole-dipole interaction of the colliding molecular pair, both in their ground and electronic excited states, as well as their interaction with the two laser fields. We apply adiabatic elimination of the electronic excited state to reduce the size of the dressed-state basis in which the dressed Hamiltoninan is expressed. In an application, we investigate the feasibility of two-photon collisional shielding between two \NaK molecules, which could be favored by the Raman resonance condition suppressing unwanted spontaneous emission and photon scattering. We demonstrate the influence of the laser Rabi frequencies on the dynamics through the computation of elastic, inelastic, and reactive collision rates.