Quasi-Universal Dipolar Scattering in Cold and Ultracold Gases

TL;DR

This paper studies how the scattering cross section of aligned dipolar molecules behaves across different low-temperature energy regimes, revealing universal patterns and potential deviations.

Contribution

It provides a comprehensive analysis of dipolar scattering, deriving simple formulas for different energy regimes and highlighting the universality and deviations in scattering behavior.

Findings

Cross section declines inversely with collision speed at certain energies.

Cross section becomes energy-independent at lower energies.

Universal behavior with expected deviations in intermediate energies.

Abstract

We investigate the scattering cross section of aligned dipolar molecules in low-temperature gases. Over a wide range of collision energies relevant to contemporary experiments, the cross section declines in inverse proportion to the collision speed, and is given nearly exactly by a simple semiclassical formula. At yet lower energies, the cross section becomes independent of energy, and is reproduced within the Born approximation to within corrections due to the s-wave scattering length. While these behaviors are universal for all polar molecules, nevertheless interesting deviations from universality are expected to occur in the intermediate energy range.