Dynamical instability in the S=1 Bose-Hubbard model

TL;DR

This paper investigates the dynamical instabilities of superfluid flows in the S=1 Bose-Hubbard model, revealing how spin interactions and particle number parity influence phase boundaries and spin modulations.

Contribution

It provides a comprehensive analysis of dynamical instabilities in the S=1 Bose-Hubbard model, highlighting the effects of spin interactions and particle number parity on phase diagrams.

Findings

Superfluid flow decays at different critical momenta for spin-1 compared to spinless cases.

The dynamical phase boundary varies significantly with even or odd particle numbers per site.

Spin modulations are highly affected by the presence of a uniform magnetic field.

Abstract

We study the dynamical instabilities of superfluid flows in the S=1 Bose-Hubbard model. The time evolution of each spin component in a condensate is calculated based on the dynamical Gutzwiller approximation for a wide range of interactions, from a weakly correlated regime to a strongly correlated regime near the Mott-insulator transition. Owing to the spin-dependent interactions, the superfluid flow of the spin-1 condensate decays at a different critical momentum from a spinless case when the interaction strength is the same. We furthermore calculate the dynamical phase diagram of this model and clarify that the obtained phase boundary has very different features depending on whether the average number of particles per site is even or odd. Finally, we analyze the density and spin modulations that appear in association with the dynamical instability. We find that spin modulations are highly sensitive to the presence of a uniform magnetic field.