Two-dimensional expansion of a condensed dense Bose gas

TL;DR

This paper investigates the expansion and shock wave formation in a strongly interacting Bose gas passing an obstacle, using a modified nonlinear equation to compare with weakly interacting systems.

Contribution

It introduces a slave-boson based nonlinear equation for strongly interacting Bose gases and compares its dynamics to the Gross-Pitaevskii equation.

Findings

Strongly interacting Bose gas shows similar shock wave behavior to weakly interacting gases.

The dynamics are slower in the strongly interacting system.

The nonlinear equation differs from the Gross-Pitaevskii equation in nonlinearity.

Abstract

We study the expansion dynamics of a condensate in a strongly interacting Bose gas in the presence of an obstacle. Our focus is on the generation of shock waves after the Bose gas has passed the obstacle. The strongly interacting Bose gas is described in the slave-boson representation. A saddle-point approximation provides a nonlinear equation of motion for the macroscopic wave function, analogous to the Gross-Pitaevskii equation of a weakly interacting Bose gas but with different nonlinearity. We compare the results with the Gross-Pitaevskii dynamics of a weakly interacting Bose gas and find a similar behavior with a slower behavior of the strongly interacting system.