Dynamics of first-order quantum phase transitions in extended Bose-Hubbard model: From density wave to superfluid and vice-versa

TL;DR

This study explores the nonequilibrium dynamics of the extended Bose-Hubbard model during first-order phase transitions, revealing unexpected scaling laws and complex domain formation phenomena.

Contribution

It introduces a time-dependent Gutzwiller approach to analyze first-order quantum phase transitions and uncovers novel scaling behaviors and domain dynamics.

Findings

Scaling laws for correlation length and vortex density during DW to SF transition.

Observation of coexisting SF and DW domains after crossing the transition.

Loss of SF coherence and formation of large DW domains depending on initial conditions.

Abstract

In this paper, we study the nonequilibrium dynamics of the Bose-Hubbard model with the nearest-neighbor repulsion by using time-dependent Gutzwiller (GW) methods. In particular, we vary the hopping parameters in the Hamiltonian as a function of time, and investigate the dynamics of the system from the density wave (DW) to the superfluid (SF) crossing a first-order phase transition and vice-versa. From the DW to SF, we find scaling laws for the correlation length and vortex density with respect to the quench time. This is a reminiscence of the Kibble-Zurek scaling for continuous phase transitions and contradicts the common expectation. We give a possible explanation for this observation. On the other hand from the SF to DW, the system evolution depends on the initial SF state. When the initial state is the ground-state obtained by the static GW methods, a coexisting state of the SF and DW domains forms after passing through the critical point. Coherence of the SF order parameter is lost as the system evolves. This is a phenomenon similar to the glass transition in classical systems. When the state starts from the SF with small local phase fluctuations, the system obtains a large-size DW-domain structure with thin domain walls.