Observation of many-body quantum phase transitions beyond the Kibble-Zurek mechanism

TL;DR

This paper investigates quantum phase transitions beyond the Kibble-Zurek mechanism by observing multiple critical behaviors in a superfluid to Mott insulator transition, revealing competing quantum critical mechanisms.

Contribution

It introduces an improved band-mapping method to study quantum critical behavior and uncovers evidence of multiple competing quantum critical mechanisms.

Findings

Observed different critical behaviors in steady-state and phase-oscillation regions.

Detected two different values for the same quantum critical parameter.

Results challenge the universality of the Kibble-Zurek mechanism.

Abstract

Quantum critical behavior of many-body phase transitions is one of the most fascinating yet challenging questions in quantum physics. Here, we improved the band-mapping method to investigate the quantum phase transition from superfluid to Mott insulators, and we observed the critical behaviors of quantum phase transitions in both dynamical steady-state-relaxation region and phase-oscillation region. Based on various observables, two different values for the same quantum critical parameter are observed. This result is beyond a universal-scaling-law description of quantum phase transitions known as the Kibble-Zurek mechanism, and suggests that multiple quantum critical mechanisms are competing in many-body quantum phase transition experiments in inhomogeneous systems.