Quantum quench dynamics as a shortcut to adiabaticity

TL;DR

This paper demonstrates an experimental quantum algorithm using quench steps on Rydberg atom arrays to efficiently prepare ground states, overcoming limitations of traditional adiabatic methods in large quantum systems.

Contribution

It introduces a novel 'sweep-quench-sweep' quantum algorithm that acts as a shortcut to adiabaticity, validated through experiments on a programmable quantum simulator.

Findings

The quench-based approach outperforms traditional adiabatic algorithms.

Quenches enable large state reconfigurations, akin to quantum many-body scars.

The method effectively prepares ground states in large-scale quantum systems.

Abstract

The ability to efficiently prepare ground states of quantum Hamiltonians via adiabatic protocols is typically limited by the smallest energy gap encountered during the quantum evolution. This presents a key obstacle for quantum simulation and realizations of adiabatic quantum algorithms in large systems, particularly when the adiabatic gap vanishes exponentially with system size. Using QuEra's Aquila programmable quantum simulator based on Rydberg atom arrays, we experimentally demonstrate a method to circumvent such limitations. Specifically, we develop and test a "sweep-quench-sweep" quantum algorithm in which the incorporation of a quench step serves as a remedy to the diverging adiabatic timescale. These quenches introduce a macroscopic reconfiguration between states separated by an extensively large Hamming distance, akin to quantum many-body scars. Our experiments show that this approach significantly outperforms the adiabatic algorithm, illustrating that such quantum quench algorithms can provide a shortcut to adiabaticity for large-scale many-body quantum systems.