Dynamics of interacting bosons in a two-leg ring ladder with artificial magnetic flux and ac-driven modulations

TL;DR

This paper explores the nonequilibrium behavior of interacting bosons in a two-leg ring ladder with artificial magnetic flux and ac-driven modulations, revealing control over particle currents and nonlinear self-trapping phenomena.

Contribution

It introduces a mean-field framework to analyze how artificial flux and ac-driving influence bosonic transport, including the control of current direction and self-trapping effects.

Findings

Artificial flux induces directed particle currents.

Tuning drive frequency controls current intensity and direction.

Strong interactions lead to nonlinear self-trapping.

Abstract

We investigate the nonequilibrium dynamics of interacting bosons in a two-leg ring ladder pierced by an artificial magnetic flux, where the particles are initially localized in the central sites of both rings, and the ac-driven local energy shifts are applied to the remaining lattice sites. Within the mean-field approximation, we demonstrate the emergence of nonlinear self-trapping for strong interparticle interactions, and characterize the distinct excitation regimes in the absence of the inter-ring tunneling. The artificial magnetic flux typically introduces Peierls phase factors, which induces complex-valued hopping amplitudes and leads to directed net particle currents along the chains. By further incorporating the finite inter-ring coupling and biased intra-ring hopping, we reveal that the tuning of the drive frequency and Peierls phase allows the precise control over both the intensity and direction of particle currents, which facilitates the transition between chiral and antichiral dynamics. These findings offer insights into the coherent manipulation of matter-wave transports in closed-loop lattice configurations and the exploration of nonequilibrium synthetic quantum systems in related fields.