Systematic Magnus-based approach for suppressing leakage and non-adiabatic errors in quantum dynamics

TL;DR

This paper introduces a systematic Magnus-based perturbative method to correct quantum control pulses, effectively suppressing leakage and non-adiabatic errors in quantum systems during evolution and state preparation.

Contribution

It provides a novel, systematic approach using the Magnus expansion to correct control pulses, improving quantum gate fidelity and reducing errors in various quantum applications.

Findings

Effective suppression of leakage errors demonstrated.

Improved adiabatic state transfer fidelity shown.

Applicable to superconducting qubits and Landau-Zener problems.

Abstract

We present a systematic, perturbative method for correcting quantum gates to suppress errors that take the target system out of a chosen subspace. It addresses the generic problem of non-adiabatic errors in adiabatic evolution and state preparation, as well as general leakage errors due to spurious couplings to undesirable states. The method is based on the Magnus expansion: by correcting control pulses, we modify the Magnus expansion of an initially-given, imperfect unitary in such a way that the desired evolution is obtained. Applications to adiabatic quantum state transfer, superconducting qubits and generalized Landau-Zener problems are discussed.