Pseudopotentials for an ultracold dipolar gas

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.TMW acknowledges the financial support of the EPSRC [EP/J017639/1], and GJC acknowledges the financial support of the Royal Society and Gonville & Caius College. There is Open Access to this paper and data available at https://www.repository.cam.ac.uk.This is the author accepted manuscript. The final version is available at http://journals.aps.org/pra/abstract/10.1103/PhysRevA.93.022706