Probing Many-Body Localization by Spin Noise Spectroscopy

TL;DR

This paper introduces a non-invasive spin noise spectroscopy method to identify many-body localization in disordered spin systems by analyzing spin fluctuation signals, distinguishing localized from delocalized phases.

Contribution

It demonstrates how cross-correlation spin noise spectroscopy can differentiate MBL from Anderson localization and delocalization, supported by numerical simulations and a phenomenological model.

Findings

Spin noise signals can distinguish MBL from other phases.

Cross-correlation SNS effectively separates localized and delocalized states.

Numerical calculations validate the proposed detection method.

Abstract

We propose to apply spin noise spectroscopy (SNS) to detect many-body localization (MBL) in disordered spin systems. The SNS methods are relatively non-invasive technique to probe spontaneous spin fluctuations. We here show that the spin noise signals obtained by cross-correlation SNS with two probe beams can be used to separate the MBL phase from a noninteracting Anderson localized phase and a delocalized (diffusive) phase in the studied models for which we numerically calculate real time spin noise signals and their power spectra. For the archetypical case of the disordered XXZ spin chain we also develop a simple phenomenological model.