Cavity QED with separate photon storage and qubit readout modes

TL;DR

This paper demonstrates a superconducting cavity QED system with separate modes for qubit readout and photon storage, enabling advanced quantum operations and scalable quantum logic schemes.

Contribution

It introduces a cavity design with distinct photon modes for storage and readout, facilitating improved quantum control and potential two-qubit gate implementation.

Findings

Successfully engineered modes with different lifetimes in a single cavity.

Demonstrated photon coherence measurement via sideband techniques.

Showed scaling of Rabi frequency with photon number n.

Abstract

We present the realization of a cavity quantum electrodynamics setup in which photons of strongly different lifetimes are engineered in different harmonic modes of the same cavity. We achieve this in a superconducting transmission line resonator with superconducting qubits coupled to the different modes. One cavity mode is strongly coupled to a detection line for qubit state readout, while a second long lifetime mode is used for photon storage and coherent quantum operations. We demonstrate sideband based measurement of photon coherence, generation of n photon Fock states and the scaling of the sideband Rabi frequency with the square root of n using a scheme that may be extended to realize sideband based two-qubit logic gates.