# Kibble-Zurek universality in a strongly interacting Fermi superfluid

## TL;DR

This study demonstrates the universal Kibble-Zurek mechanism in a strongly interacting Fermi superfluid, showing consistent vortex formation scaling across different microscopic regimes and identifying universal vortex core scaling.

## Contribution

First experimental observation of Kibble-Zurek universality in a strongly interacting Fermi superfluid across different microscopic descriptions.

## Key findings

- Vortex density scales with quench rate following a universal power law.
- The scaling exponent remains constant due to the system's $U(1)$ symmetry.
- Vortex densities saturate at rapid quenches, scaled by vortex core area.

## Abstract

Near a continuous phase transition, systems with different microscopic origins display universal dynamics if their underlying symmetries are compatible. In a thermally quenched system, the Kibble-Zurek mechanism for the creation of topological defects unveils this universality through a characteristic power-law exponent, which captures the dependence of the defect density on the quench rate. Here, we report the observation of the Kibble-Zurek universality in a strongly interacting Fermi superfluid. As the system's microscopic description is tuned from bosonic to fermionic, the quench formation of vortices reveals a constant scaling exponent arising from the $U(1)$ gauge symmetry of the system. For rapid quenches, destructive vortex collisions lead to the saturation of their densities, whose values can be universally scaled by the interaction-dependent area of the vortex cores.