Exploring the Single-Particle Mobility Edge in a One-Dimensional Quasiperiodic Optical Lattice

TL;DR

This paper provides experimental evidence for a single-particle mobility edge in a one-dimensional quasiperiodic optical lattice, demonstrating coexistence of localized and extended states due to correlated disorder.

Contribution

First experimental observation of a single-particle mobility edge in a 1D quasiperiodic optical lattice, confirming theoretical predictions.

Findings

Existence of a regime with coexisting localized and extended states

Good agreement between experimental results and theoretical simulations

Identification of a critical energy separating localized and extended states

Abstract

A single-particle mobility edge (SPME) marks a critical energy separating extended from localized states in a quantum system. In one-dimensional systems with uncorrelated disorder, a SPME cannot exist, since all single-particle states localize for arbitrarily weak disorder strengths. However, if correlations are present in the disorder potential, the localization transition can occur at a finite disorder strength and SPMEs become possible. In this work, we find experimental evidence for the existence of such a SPME in a one-dimensional quasi-periodic optical lattice. Specifically, we find a regime where extended and localized single-particle states coexist, in good agreement with theoretical simulations, which predict a SPME in this regime.