Physicists successfully observe Kibble–Zurek scaling in an atomic Fermi superfluid

Amazing stuff! Almost super exotic physics! 😊

"The Kibble–Zurek (KZ) mechanism is a theoretical framework introduced by physicists Tom Kibble and Wojciech Zurek. This framework essentially describes the formation of topological defects while systems undergo non-equilibrium phase transitions.

Researchers ... recently observed KZ scaling in a homogeneous and strongly interacting Fermi gas as it was transitioning into a superfluid. ...

While KZ scaling is applicable to a wide range of systems, including superfluids, ferroelectrics, superconductors, ion traps and Rydberg atom arrays, so far it has primarily been observed in some of these systems. The main objective of the study by Lee and his colleagues was to observe KZ scaling in a Fermi superfluid, which has so far proved particularly challenging. ..."

From the abstract:

"The Kibble–Zurek mechanism is a theoretical framework that describes the formation and scaling of topological defects in symmetry-breaking phase transitions. It was originally conceptualized for superfluid helium. The theory predicts that the number of quantum vortices should scale as a power law with the rate at which the system passes through the lambda transition, but demonstrating this effect has been elusive in experiments using superfluid systems. Here, we report the observation of Kibble–Zurek scaling in a homogeneous, strongly interacting Fermi gas undergoing a superfluid phase transition. We investigate the superfluid transition using temperature and interaction strength as two distinct control parameters. The microscopic physics of condensate formation is markedly different for the two quench parameters, as shown by the two orders of magnitude difference in the condensate formation timescale. However, regardless of the thermodynamic direction in which the system passes through a phase transition, the Kibble–Zurek exponent is identically observed to be about 0.68, in good agreement with theoretical predictions. This work experimentally demonstrates the theoretical proposal laid out for liquid helium, which is in the same universality class as strongly interacting Fermi gases."

Physicists successfully observe Kibble–Zurek scaling in an atomic Fermi superfluid

Universal Kibble–Zurek scaling in an atomic Fermi superfluid (no public access)

Observation of universal Kibble-Zurek scaling in an atomic Fermi superfluid (pre-print version)

Time-of-flight image of an atomic cloud of 6Li, where the dark density depletions are quantum vortices