Variational Quantum Gate Optimization at the Pulse Level

TL;DR

This paper demonstrates the experimental implementation of variational quantum gate optimization at the pulse level for fixed-frequency transmon qubits, successfully optimizing two- and three-qubit gates based on native interactions, while identifying parameter drift as a key challenge.

Contribution

It introduces a variational optimization protocol informed by the physical Hamiltonian and demonstrates its effectiveness on native qubit interactions, highlighting current limitations.

Findings

Successful optimization of two- and three-qubit gates

Parameter drift limits the optimization of Floquet-engineered gates

Variational protocol aligns with native qubit interactions

Abstract

We experimentally investigate the viability of a variational quantum gate optimization protocol informed by the underlying physical Hamiltonian of fixed-frequency transmon qubits. The utility of the scheme is demonstrated through the successful experimental optimization of two and three qubit quantum gates tailored on the native cross-resonance interaction. The limits of such a strategy are investigated through the optimization of a gate based on Floquet-engineered three-qubit interactions, however parameter drift is identified as a key limiting factor preventing the implementation of such a scheme which the variational optimization protocol is unable to overcome.