Optimal quantum annealing: A variational shortcut to adiabaticity approach

TL;DR

This paper extends variational counterdiabatic techniques to open quantum systems, demonstrating improved adiabaticity and success probability in quantum annealing even with dissipation.

Contribution

It introduces a variational approach for suppressing diabatic transitions in Lindbladian dynamics, showing unitary ans"atze are effective for dissipative quantum annealing.

Findings

Unitary counterdiabatic ans"atze work for dissipative dynamics.

The approach improves open-system adiabaticity.

Success probability of quantum annealing is enhanced.

Abstract

Suppressing unwanted transitions out of the instantaneous ground state is a major challenge in unitary adiabatic quantum computation. A recent approach consists in building counterdiabatic potentials approximated using variational strategies. In this contribution, we extend this variational approach to Lindbladian dynamics, having as a goal the suppression of diabatic transitions between pairs of Jordan blocks in quantum annealing. We show that, surprisingly, unitary counterdiabatic ans\"atze are successful for dissipative dynamics as well, allowing for easier experimental implementations compared to Lindbladian ans\"atze involving dissipation. Our approach not only guarantees improvements of open-system adiabaticity but also enhances the success probability of quantum annealing.