Virtual mitigation of coherent non-adiabatic transitions by echo verification

TL;DR

This paper introduces an adiabatic echo verification protocol that reduces errors from non-adiabatic transitions and hardware noise in quantum algorithms, improving measurement accuracy without requiring negative-time dynamics.

Contribution

The proposed method is a novel protocol that mitigates both coherent and incoherent errors in quantum adiabatic processes using positive-time dynamics only.

Findings

Reduces estimator bias compared to standard methods.

Achieves up to quadratic improvement in measurement accuracy.

Mitigates errors from hardware imperfections and non-adiabatic transitions.

Abstract

Transitions out of the ground space limit the performance of quantum adiabatic algorithms, while hardware imperfections impose stringent limitations on the circuit depth. We propose an adiabatic echo verification protocol which mitigates both coherent and incoherent errors, arising from non-adiabatic transitions and hardware noise, respectively. Quasi-adiabatically evolving forward and backwards allows for an echo-verified measurement of any observable. In addition to mitigating hardware noise, our method uses positive-time dynamics only. Crucially, the estimator bias of the observable is reduced when compared to standard adiabatic preparation, achieving up to a quadratic improvement.