Quench Dynamics of Finite Bosonic Ensembles in Optical Lattices with Spatially Modulated Interactions

TL;DR

This study explores the nonequilibrium dynamics of few bosons in optical lattices with spatially modulated interactions, revealing complex tunneling, excitation modes, and directed transport phenomena induced by quenches in interaction parameters.

Contribution

It introduces a detailed analysis of how spatially modulated interactions and their quenches affect bosonic tunneling, excitation modes, and transport in finite optical lattices, highlighting new dynamical behaviors.

Findings

Enhanced interatomic imbalance due to quenches in interaction parameters

Observation of breathing and cradle excitation modes with increased inhomogeneity

Directed momentum transfer and population transfer between lattice sites

Abstract

The nonequilibrium quantum dynamics of few boson ensembles which experience a spatially modulated interaction strength and are confined in finite optical lattices is investigated. We utilize a cosinusoidal spatially modulated effective interaction strength which is characterized by its wavevector, inhomogeneity amplitude, interaction offset and a phase. Performing quenches either on the wavevector or the phase of the interaction profile an enhanced imbalance of the interatomic repulsion between distinct spatial regions of the lattice is induced. Following both quench protocols triggers various tunneling channels and a rich excitation dynamics consisting of a breathing and a cradle mode. All modes are shown to be amplified for increasing inhomogeneity amplitude of the interaction strength. Especially the phase quench induces a directional transport enabling us to discern energetically, otherwise, degenerate tunneling pathways. Moreover, a periodic population transfer between distinct momenta for quenches of increasing wavevector is observed, while a directed occupation of higher momenta can be achieved following a phase quench. Finally, during the evolution regions of partial coherence are revealed between the predominantly occupied wells.