Pulse shaping by coupled-cavities: Single photons and qudits

TL;DR

This paper demonstrates how dynamically tuning coupled cavities with atoms can control photon emission and quantum states, enabling high-fidelity photon confinement, pulse shaping, and superposition in solid-state quantum networks.

Contribution

It introduces a method for dynamic cavity coupling control via atom tuning, enabling novel photon shaping and quantum state engineering in coupled-cavity systems.

Findings

Near-Gaussian single-photon pulses can be generated.

High fidelity excitation confinement and reversible state transport are achievable.

The scheme is practical within current experimental capabilities.

Abstract

Dynamic coupling of cavities to a quantum network is of major interest to distributed quantum information processing schemes based on cavity quantum electrodynamics. This can be achieved by active tuning a mediating atom-cavity system. In particular, we consider the dynamic coupling between two coupled cavities, each interacting with a two-level atom, realized by tuning one of the atoms. One atom-field system can be controlled to become maximally and minimally coupled with its counterpart, allowing high fidelity excitation confinement, Q-switching and reversible state transport. As an application, we first show that simple tuning can lead to emission of near-Gaussian single-photon pulses that is significantly different from the usual exponential decay in a passive cavity-based system. The influences of cavity loss and atomic spontaneous emission are studied in detailed numerical simulations, showing the practicality of these schemes within the reach of current experimental technology in solid-state environment. We then show that when the technique is employed to an extended coupled-cavity scheme involving a multi-level atom, arbitrary temporal superposition of single photons can be engineered in a deterministic way.