Photon transfer in ultrastrongly coupled three-cavity arrays

TL;DR

This paper investigates photon transfer in a three-cavity array with a central qubit, revealing that ultrastrong coupling enables photon transfer despite inhomogeneous coupling, with potential applications in quantum networks.

Contribution

It demonstrates how ultrastrong coupling affects photon transfer in a three-cavity array, highlighting singularities and potential for scalable quantum communication.

Findings

Inhomogeneous coupling prevents complete photon transfer in the strong coupling regime.

Ultrastrong coupling introduces singularities in transfer time, enabling transfer.

Model is feasible with current circuit QED technology.

Abstract

We study the photon transfer along a linear array of three coupled cavities where the central one contains an interacting two-level system in the strong and ultrastrong coupling regimes. We find that an inhomogeneously coupled array forbids a complete single-photon transfer between the external cavities when the central one performs a Jaynes-Cummings dynamics. This is not the case in the ultrastrong coupling regime, where the system exhibits singularities in the photon transfer time as a function of the cavity-qubit coupling strength. Our model can be implemented within the state-of-the-art circuit quantum electrodynamics technology and it represents a building block for studying photon state transfer through scalable cavity arrays.