# Dynamic formation of quasicondensate and spontaneous vortices in a strongly interacting Fermi gas

## TL;DR

This study investigates the dynamics of superfluid transition in a strongly interacting Fermi gas, revealing pseudogap behavior, spontaneous vortex formation, and scaling laws consistent with Kibble-Zurek theory, advancing understanding of many-body physics.

## Contribution

It demonstrates quench-induced superfluid dynamics, vortex formation, and scaling laws in a strongly interacting Fermi gas, highlighting pseudogap physics and quantum turbulence.

## Key findings

- Nonzero quasi-condensate above T_c indicates pseudogap physics.
- Spontaneous vortices form during superfluid transition.
- Vortex density scales with formation time following Kibble-Zurek theory.

## Abstract

We report an experimental study of quench dynamics across the superfluid transition temperature $T_c$ in a strongly interacting Fermi gas by ramping down the trapping potential. The nonzero quasi-condensate number $N_0$ at temperature significantly above $T_c$ in the unitary and the BEC regimes reveals the pseudogap physics. Below $T_c$, a rapid growth of $N_0$ is accompanied by spontaneous generation of tens of vortices. We observe a power law scaling of the vortex density versus the quasi-condensate formation time, consistent with the Kibble-Zurek theory. Our work provides an example of studying emerged many-body physics by quench dynamics and paves the way for studying the quantum turbulence in a strongly interacting Fermi gas.