All-microwave manipulation of superconducting qubits with a fixed-frequency transmon coupler

TL;DR

This paper presents a method for all-microwave control of fixed-frequency superconducting qubits using a coupler transmon to implement high-fidelity gates with minimal noise and wiring complexity.

Contribution

It introduces a coupler-assisted swap interaction for fixed-frequency transmons enabling all-microwave controlled-Z gates, which is a novel approach in superconducting qubit control.

Findings

High drive efficiency achieved

Small residual interactions over wide detuning range

Successful implementation of controlled-Z gate

Abstract

All-microwave control of fixed-frequency superconducting quantum computing circuits is advantageous for minimizing the noise channels and wiring costs. Here we introduce a swap interaction between two data transmons assisted by the third-order nonlinearity of a coupler transmon under a microwave drive. We model the interaction analytically and numerically and use it to implement an all-microwave controlled-Z gate. The gate based on the coupler-assisted swap transition maintains high drive efficiency and small residual interaction over a wide range of detuning between the data transmons.