Shallow quantum circuits are robust hunters for quantum many-body scars

TL;DR

This paper demonstrates that shallow quantum circuits can effectively identify quantum many-body scar states, leveraging current hardware limitations as a resource for diagnosing complex quantum states.

Contribution

The authors introduce a shallow variational eigensolver that successfully targets quantum many-body scars, providing a new diagnostic approach compatible with noisy intermediate-scale quantum computers.

Findings

Shallow circuits can detect quantum many-body scars.

The method is robust against noise.

It serves as a versatile diagnostic tool.

Abstract

Presently, noisy intermediate-scale quantum computers encounter significant technological challenges that make it impossible to generate large amounts of entanglement. We leverage this technological constraint as a resource and demonstrate that a shallow variational eigensolver can be trained to successfully target quantum many-body scar states. Scars are area-law high-energy eigenstates of quantum many-body Hamiltonians, which are sporadic and immersed in a sea of volume-law eigenstates. We show that the algorithm is robust and can be used as a versatile diagnostic tool to uncover quantum many-body scars in arbitrary physical systems.