Quantum Fluctuations in Dipolar Bose Gases

TL;DR

This paper studies how quantum fluctuations affect dipolar Bose gases using Bogoliubov-de Gennes theory, providing analytical spectra and quantum corrections to their dynamics, with implications for experimental detection of beyond mean-field effects.

Contribution

It introduces an analytical approach to evaluate quantum fluctuation effects in dipolar Bose gases and derives corrected equations of motion for trapped systems.

Findings

Quantum fluctuations significantly influence the ground state and excitations.

Analytical Bogoliubov spectrum obtained for large particle numbers.

Predictions suggest feasible experimental detection of beyond mean-field effects.

Abstract

We investigate the influence of quantum fluctuations upon dipolar Bose gases by means of the Bogoliubov-de Gennes theory. Thereby, we make use of the local density approximation to evaluate the dipolar exchange interaction between the condensate and the excited particles. This allows to obtain the Bogoliubov spectrum analytically in the limit of large particle numbers. After discussing the condensate depletion and the ground-state energy correction, we derive quantum corrected equations of motion for harmonically trapped dipolar Bose gases by using superfluid hydrodynamics. These equations are subsequently applied to analyze the equilibrium configuration, the low-lying oscillation frequencies, and the time-of-flight dynamics. We find that both atomic magnetic and molecular electric dipolar systems offer promising scenarios for detecting beyond mean-field effects.