First-order sidebands in circuit QED using qubit frequency modulation

TL;DR

This paper proposes a method to achieve faster first-order sideband transitions in circuit QED by modulating qubit frequency with flux bias, enabling improved qubit-resonator interactions and high-fidelity quantum gates.

Contribution

It introduces a novel approach using flux-bias line modulation to realize first-order sidebands, enhancing speed and tunability of qubit interactions in circuit QED.

Findings

First-order sideband transitions can be achieved with flux-bias modulation.

The technique enables faster qubit-resonator interactions.

High fidelity CNOT operations are feasible with this method.

Abstract

Sideband transitions have been shown to generate controllable interaction between superconducting qubits and microwave resonators. Up to now, these transitions have been implemented with voltage drives on the qubit or the resonator, with the significant disadvantage that such implementations only lead to second-order sideband transitions. Here we propose an approach to achieve first-order sideband transitions by relying on controlled oscillations of the qubit frequency using a flux-bias line. Not only can first-order transitions be significantly faster, but the same technique can be employed to implement other tunable qubit-resonator and qubit-qubit interactions. We discuss in detail how such first-order sideband transitions can be used to implement a high fidelity controlled-NOT operation between two transmons coupled to the same resonator.