Thermally assisted adiabatic quantum computation

TL;DR

This paper investigates how a thermal environment influences adiabatic quantum computation, revealing that under certain conditions, the environment can improve performance by aiding thermal mixing and relaxation, especially with superohmic baths.

Contribution

It demonstrates that thermal environments can enhance adiabatic quantum computation performance through specific mechanisms, including thermal mixing and relaxation, without prior energy spectrum knowledge.

Findings

Superohmic environments can improve quantum speedup.

Thermal mixing near anticrossing enhances scaling.

Relaxation after anticrossing provides performance boost.

Abstract

We study the effect of a thermal environment on adiabatic quantum computation using the Bloch-Redfield formalism. We show that in certain cases the environment can enhance the performance in two different ways: (i) by introducing a time scale for thermal mixing near the anticrossing that is smaller than the adiabatic time scale, and (ii) by relaxation after the anticrossing. The former can enhance the scaling of computation when the environment is superohmic, while the latter can only provide a prefactor enhancement. We apply our method to the case of adiabatic Grover search and show that performance better than classical is possible with a superohmic environment, with no a priori knowledge of the energy spectrum.