Effective potential and scattering length of shielding polar molecules

TL;DR

This paper analyzes how different electromagnetic shielding techniques affect the effective potential and scattering length of ultracold polar molecules, revealing methods to suppress attractive interactions and maintain quantum degeneracy.

Contribution

It derives the effective potential for polar molecules under various shielding fields and compares their effectiveness in suppressing attractive forces, including complete cancellation with certain methods.

Findings

Partial suppression of attractive interactions by first two shielding methods

Construction of bound states with different polarization shapes using second method

Complete cancellation of residual attractive forces with the last shielding method

Abstract

We investigate the effective potential and scattering length of ultracold polar molecules under different shielding techniques. First, we derive the effective potential for two polar molecules in the presence of an elliptical polarization field, combined elliptical and linear polarization fields, and combined elliptical polarization and static fields. The effective potential is then expressed as a sum of a zero-range contact interaction and a long-range dipole-dipole interaction under the Born approximation. We find that the first two shielding methods only partially suppress attractive interactions, while the second method allows for the construction of bound states with different polarization shapes. The last shielding method can achieve complete cancellation of residual attractive forces, which is particularly significant for maintaining quantum degeneracy in ultracold dipolar systems. Our results provide a comprehensive understanding of the effective potential and scattering length of shielding polar molecules, which is crucial for studying many-body physics in ultracold dipolar systems.