Nonequilibrium magnetic dynamics of the two-component Bose-Hubbard model

TL;DR

This paper investigates the nonequilibrium magnetic dynamics of the two-component Bose-Hubbard model using an advanced numerical method, revealing diverse quantum spin behaviors, thermalization processes, and phase transitions under various interaction protocols.

Contribution

It introduces a two-component nonequilibrium bosonic dynamical mean-field theory to study complex magnetic dynamics in the Bose-Hubbard model, highlighting new insights into thermalization and Floquet-driven phase transitions.

Findings

Slow thermalization leads to long-lived metastable states.

Weak interactions cause rapid two-step relaxation to equilibrium.

Periodic modulation induces a magnetic to unordered phase transition.

Abstract

A central challenge in strongly interacting many-body systems is understanding the far-from-equilibrium dynamics. Here, we study the many-body magnetic dynamics of the two-component Bose-Hubbard model by developing a two-component extension of nonequilibrium bosonic dynamical mean-field theory. Using this numerical method, we uncover rich quantum spin dynamics via inter-species interaction quenches. A sudden ramp-up of interactions induces slow thermalization, leading to a long-lived metastable state, whereas quenching to weak interactions results in rapid thermal equilibrium, featuring a two-step relaxation behavior through distinct exponential decays. Furthermore, under periodic modulation of the inter-species interactions, emergent Floquet dynamics drives a transition from a magnetic to an unordered phase.