Conductance transition with interacting bosons in an Aharonov-Bohm cage

TL;DR

This paper investigates how interactions and quantum effects influence conductance in an Aharonov-Bohm cage, revealing a transition from insulating to conducting states and the dynamics of steady states in different regimes.

Contribution

It introduces a detailed analysis of transport in an interacting bosonic Aharonov-Bohm cage, highlighting the quantum-classical crossover and steady state complexity.

Findings

Insulating behavior persists up to a critical pump strength with mean field interactions.

Quantum regime enables particle pair transport and weak conductance below critical pump.

A rapid transition from quantum to classical behavior occurs with increasing pump strength.

Abstract

We study transport of interacting bosons through an Aharonov-Bohm cage - a building block of flat band networks - with coherent pump and sink leads. In the absence of interactions the cage is insulating due to destructive interference. We find that the cage stays insulating up to a critical value of the pump strength in the presence of mean field interactions, while the quantum regime induces particle pair transport and weak conductance below the critical pump strength. A swift crossover from quantum into the classical regime upon further pump strength increase is observed. We solve the time dependent master equations for the density matrix of the many body problem both in the classical, pure quantum, and pseudoclassical regimes. We start with an empty cage and switch on driving. We characterize the transient dynamics, and the complexity of the resulting steady states and attractors. Our results can be readily realized using experimental platforms involving interacting ultracold atoms and photons on finetuned optical lattices.