Microscopic description of anisotropic low-density dipolar Bose gases in two dimensions

TL;DR

This paper provides a microscopic analysis of low-density anisotropic dipolar Bose gases in two dimensions, examining how anisotropy affects ground state properties and comparing results with mean field theories.

Contribution

It introduces a series expansion for the two-body problem, enabling accurate Monte Carlo simulations and revealing that anisotropy has minimal impact in the universal regime.

Findings

Anisotropy has negligible effect on ground state properties in the universal regime.

Scaling in the gas parameter persists despite anisotropy.

The scattering length effectively characterizes the system's physics.

Abstract

A microscopic description of the zero energy two-body ground state and many-body static properties of anisotropic homogeneous gases of bosonic dipoles in two dimensions at low densities is presented and discussed. By changing the polarization angle with respect to the plane, we study the impact of the anisotropy, present in the dipole--dipole interaction, on the energy per particle, comparing the results with mean field predictions. We restrict the analysis to the regime where the interaction is always repulsive, although the strength of the repulsion depends on the orientation with respect to the polarization field. We present a series expansion of the solution of the zero energy two-body problem which allows us to find the scattering length of the interaction and to build a suitable Jastrow factor that we use as a trial wave function for both a variational and diffusion Monte Carlo simulation of the infinite system. We find that the anisotropy has an almost negligible impact on the ground state properties of the many-body system in the universal regime where the scattering length governs the physics of the system. We also show that scaling in the gas parameter persists in the dipolar case up to values where other isotropic interactions with the same scattering length yield different predictions.