Dynamic quantum Kerr effect in circuit quantum electrodynamics

TL;DR

This paper demonstrates a dynamic quantum Kerr effect in circuit QED by using a driven superconducting qubit to induce non-linear photon interactions, observed through resonator Wigner tomography across various photon states.

Contribution

It introduces a dynamic approach to observe quantum Kerr effects in circuit QED, expanding beyond static detuning methods and revealing non-linear photon interactions.

Findings

Observation of non-linear effects on Fock, coherent, and cat states

Demonstration of quantum Kerr effect in a dynamic regime

Resonator Wigner tomography confirms non-linear photon interactions

Abstract

A superconducting qubit coupled to a microwave resonator provides a controllable system that enables fundamental studies of light-matter interactions. In the dispersive regime, photons in the resonator exhibit induced frequency and phase shifts which are revealed in the resonator transmission spectrum measured with fixed qubit-resonator detuning. In this static detuning scheme, the phase shift is measured in the far-detuned, linear dispersion regime to avoid measurement-induced demolition of the qubit quantum state. Here we explore the qubit-resonator dispersive interaction over a much broader range of detunings, by using a dynamic procedure where the qubit transition is driven adiabatically. We use resonator Wigner tomography to monitor the interaction, revealing exotic non-linear effects on different photon states, e.g., Fock states, coherent states, and Schrodinger cat states, thereby demonstrating a quantum Kerr effect in the dynamic framework.