Speeding up Quantum Annealing with Engineered Dephasing

TL;DR

This paper demonstrates that engineered dephasing noise, via coupling to an auxiliary quantum system, can enhance quantum annealing speed through a coherent energy rescaling, with potential experimental implementations.

Contribution

It introduces a novel method of using engineered dephasing to accelerate quantum annealing by an effective energy rescaling mechanism.

Findings

Dephasing coupling enhances adiabaticity through a coherent mechanism.

Annealing speedup is linearly proportional to coupling strength.

Feasible protocols with fewer physical couplings are discussed.

Abstract

Building on the insight that engineered noise, specifically, engineered dephasing can enhance the adiabaticity of controlled quantum dynamics, we investigate how a dephasing-generating coupling to an auxiliary quantum system affects quantum annealing protocols. By calculating the exact reduced system dynamics, we show how this coupling enhances the system's adiabaticity solely through a coherent mechanism - an effective energy rescaling. We show that it can lead to an annealing speedup linearly proportional to the strength of the coupling. We discuss the experimental feasibility of the protocols, and investigate the trade-off between fidelity and implementability by examining two modified versions with fewer types of required physical couplings.