Speeding up Quantum Annealing with Engineered Dephasing. 

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.