Measurement quench in many-body systems

TL;DR

This paper proposes a novel method to induce quench dynamics in many-body quantum systems solely through measurements, eliminating the need for external perturbations, which simplifies implementation and enhances robustness.

Contribution

It introduces a measurement-based quench protocol that leverages wave function collapse, offering advantages in experimental feasibility and applications in spectroscopy and critical system analysis.

Findings

Measurement-induced quenches can effectively drive many-body dynamics.

The protocol improves resilience against decoherence.

Applications include spectroscopy and probing quantum criticality.

Abstract

Measurement is one of the key concepts which discriminates classical and quantum physics. Unlike classical systems, a measurement on a quantum system typically alters it drastically as a result of wave function collapse. Here we suggest that this feature can be exploited for inducing quench dynamics in a many-body system while leaving its Hamiltonian unchanged. Importantly, by doing away with dedicated macroscopic devices for inducing a quench -- using instead the indispensable measurement apparatus only -- the protocol is expected to be easier to implement and more resilient against decoherence. By way of various case studies, we show that our scheme also has decisive advantages beyond reducing decoherence -- for spectroscopy purposes and probing nonequilibrium scaling of critical and quantum impurity many-body systems.