Quantum purification spectroscopy

TL;DR

This paper introduces a quantum purification spectroscopy protocol that uses quenching and interferometry to extract bulk spectral features from a purified quantum system, applicable in current quantum simulation experiments.

Contribution

The paper presents a novel protocol combining quenching and interferometry to access spectral features, enabling experimental testing of many-body physics hypotheses.

Findings

Protocol captures bulk spectral features at finite times

Applicable to current quantum simulation setups

Potential to test eigenstate thermalization and localization

Abstract

We discuss a protocol based on quenching a purified quantum system that allows to capture bulk spectral features. It uses an infinite temperature initial state and an interferometric strategy to access the Loschmidt amplitude, from which the spectral features are retrieved via Fourier transform, providing coarse-grained approximation at finite times. It involves techniques available in current experimental setups for quantum simulation, at least for small systems. We illustrate possible applications in testing the eigenstate thermalization hypothesis and the physics of many-body localization.