Universal Early Coarsening of Quenched Bose Gases

TL;DR

This study explores the universal early coarsening process in quenched Bose gases, revealing how defect formation scales with cooling rates and extends beyond traditional Kibble-Zurek predictions.

Contribution

It demonstrates that early coarsening dynamics are universal and controlled by the post-critical cooling rate, influencing defect density scaling beyond the Kibble-Zurek mechanism.

Findings

Defect number scales with the cooling rate $r_2$ regardless of initial rate $r_1$

Early coarsening reduces defect density in Bose gases

Scaling behavior extends beyond Kibble-Zurek predictions

Abstract

We investigate the early coarsening dynamics of an atomic Bose gas quenched into a superfluid phase. Using a two-step quench protocol, we effectively control the cooling rates, $r_1$ and $r_2$, during and after passing through the critical region, respectively, and measure the number of quantum vortices spontaneously created in the system. The latter cooling rate $r_2$ regulates the temperature during the condensate growth, consequently controlling the early coarsening dynamics in the defect formation. We find that the defect number shows a scaling behavior with $r_2$ regardless of the initial cooling rate $r_1$, indicating universal coarsening dynamics in the early stage of condensate growth. Our results demonstrate that early coarsening not only reduces the defect density but also affects its scaling with the quench rate, which is beyond the Kibble-Zurek mechanism.