Quantum and Classical in Adiabatic Computation

TL;DR

This paper explores the interplay of quantum and classical aspects in adiabatic computation, analyzing environmental effects on quantum correlations and benchmarking quantum hardware performance.

Contribution

It introduces a framework linking classical optimization algorithms with quantum adiabatic processes and develops benchmarks to assess quantum correlations in adiabatic computation.

Findings

Environmental dephasing limits quantum correlations in adiabatic systems.

Benchmarking on D-Wave Vesuvius shows partial quantum advantage.

Quantum correlations are constrained by physical and environmental factors.

Abstract

Adiabatic transport provides a powerful way to manipulate quantum states. By preparing a system in a readily initialised state and then slowly changing its Hamiltonian, one may achieve quantum states that would otherwise be inaccessible. Moreover, a judicious choice of final Hamiltonian whose groundstate encodes the solution to a problem allows adiabatic transport to be used for universal quantum computation. However, the dephasing effects of the environment limit the quantum correlations that an open system can support and degrade the power of such adiabatic computation. We quantify this effect by allowing the system to evolve over a restricted set of quantum states, providing a link between physically inspired classical optimisation algorithms and quantum adiabatic optimisation. This new perspective allows us to develop benchmarks to bound the quantum correlations harnessed by an adiabatic computation. We apply these to the D-Wave Vesuvius machine with revealing - though inconclusive - results.