Controlling the transport of single photons by tuning the frequency of either one or two cavities in an array of coupled cavities

TL;DR

This paper presents a theoretical method to control single-photon transport in a coupled-cavity array by tuning the frequency of one or two cavities, enabling bound, resonant states, and photon trapping for quantum applications.

Contribution

It introduces a novel approach to manipulate photon states in cavity arrays through frequency tuning of specific cavities, including the formation of quantum supercavities.

Findings

Tuning one cavity's frequency creates bound states above or below the energy band.

Tuning two cavities can produce both bound and resonant states.

Resonant cavities can trap photons, forming quantum supercavities.

Abstract

We theoretically study how to control transport, bound states, and resonant states of a single photon in a one-dimensional coupled-cavity array. We find that the transport of a single photon in the cavity array can be controlled by tuning the frequency of either one or two cavities. If one of the cavities in the array has a tunable frequency, and its frequency is tuned to be larger (or smaller) than those of other cavities, then there is a photon bound state above (or below) the energy band of the coupled cavity array. However, if two cavities in the array have tunable frequencies, then there exist both bound states and resonant states. When the frequencies of the two cavities are chosen to be much larger than those of other cavities and the hopping couplings between any two nearest-neighbor cavities are weak, a single photon with a resonant wave vector can be trapped in the region between the two frequency-tunable cavities. In this case, a quantum supercavity can be formed by these two frequency-tunable cavities. We also study how to apply this photon transport control to an array of coupled superconducting transmission line resonators.