Pseudopotentials for an ultracold dipolar gas

TL;DR

This paper introduces a smooth pseudopotential for 2D ultracold dipolar gases that simplifies computations, accurately reproduces scattering properties, and significantly accelerates diffusion Monte Carlo simulations.

Contribution

A novel pseudopotential that regularizes the dipolar interaction at coalescence, enabling efficient and precise quantum many-body calculations.

Findings

2000-fold speedup in DMC calculations

Scattering phase shifts accurate to 10^{-5}

Predicted energy with 10^{-4}E_F accuracy

Abstract

A gas of ultracold molecules interacting via the long-range dipolar potential offers a highly controlled environment in which to study strongly correlated phases. However, at particle coalescence the divergent $1/r^3$ dipolar potential and associated pathological wavefunction hinder computational analysis. For a dipolar gas constrained to two dimensions we overcome these numerical difficulties by proposing a pseudopotential that is explicitly smooth at particle coalescence, resulting in a 2000-times speedup in diffusion Monte Carlo calculations. The pseudopotential delivers the scattering phase shifts of the dipolar interaction with an accuracy of $10^{-5}$ and predicts the energy of a dipolar gas to an accuracy of $10^{-4}E_\mathrm{F}$ in a diffusion Monte Carlo calculation.