Signatures of clean phases in many-body localized quantum circuits

TL;DR

This paper proposes a shallow-depth quantum circuit scheme to simulate and identify many-body localized phases in Floquet systems, enabling phase diagram mapping on near-term noisy quantum devices.

Contribution

It introduces a method using quasi-periodic circuit parameters to prevent thermalization and detect phases via integrals of motion, without needing ground state computations.

Findings

Successfully distinguishes Floquet phases in simulations

Demonstrates the scheme with a Floquet Ising model

Shows potential for phase diagram mapping on near-term quantum devices

Abstract

Many-body phenomena far from equilibrium present challenges beyond reach by classical computational resources. Digital quantum computers provide a possible way forward but noise limits their use in the near-term. We propose a scheme to simulate and characterize many-body Floquetsystems hosting a rich variety of phases that operates with a shallow depth circuit. Starting from a "clean" periodic circuit that simulates the dynamical evolution of a Floquet system, we introduce quasi-periodicity to the circuit parameters to prevent thermalization by introducing many-body localization. By inspecting the time averaged properties of the many-body integrals of motion, the phase structure can then be probed using random measurements. This approach avoids the need to compute the ground state and operates at finite energy density. We numerically demonstrate this scheme with a simulation of the Floquet Ising model of time-crystals and present results clearly distinguishing different Floquet phases in the absence of quasi-periodicity in the circuit parameters. Our results pave the way for mapping phase diagrams of exotic systems on near-term quantum devices.