Imbalance for a family of one-dimensional incommensurate models with mobility edges

TL;DR

This paper investigates four incommensurate one-dimensional models with mobility edges, revealing complex imbalance behaviors and proposing dimensionless parameters that govern long-term dynamics, supported by numerical evidence.

Contribution

It introduces a framework of dimensionless parameters controlling imbalance in models with mobility edges, including a novel analysis of non-monotonic behavior and duality relations.

Findings

Imbalance exhibits non-monotonic dependence on system parameters.

Proposed dimensionless parameters fully determine long-time imbalance.

Numerical evidence supports the control of imbalance by these parameters.

Abstract

In this paper, we look at four generalizations of the one dimensional Aubry-Andre-Harper (AAH) model which possess mobility edges. We map out a phase diagram in terms of population imbalance, and look at the system size dependence of the steady state imbalance. We find non-monotonic behaviour of imbalance with system parameters, which contradicts the idea that the relaxation of an initial imbalance is fixed only by the ratio of number of extended states to number of localized states. We propose that there exists dimensionless parameters, which depend on the fraction of single particle localized states, single particle extended states and the mean participation ratio of these states. These ingredients fully control the imbalance in the long time limit and we present numerical evidence of this claim. Among the four models considered, three of them have interesting duality relations and their location of mobility edges are known. One of the models (next nearest neighbour coupling) has no known duality but mobility edge exists and the model has been experimentally realized. Our findings are an important step forward to understanding non-equilibrium phenomena in a family of interesting models with incommensurate potentials.