A controllable single photon beam-splitter as a node of a quantum network

TL;DR

This paper proposes a controllable single-photon beam-splitter model using crossed optical cavities and a flying atom, enabling efficient photon routing and quantum operations for quantum networks.

Contribution

It introduces a novel cavity-QED-based model for a controllable photon beam-splitter and demonstrates its application in quantum network nodes for quantum information processing.

Findings

Achieves near-unity photon routing efficiency in weak-coupling regime

Enables single- and two-qubit quantum operations between network nodes

Provides timing protocols to facilitate experimental implementation

Abstract

A model for a controlled single-photon beam-splitter is proposed and analysed. It consists of two crossed optical-cavities with overlapping waists, dynamically coupled to a single flying atom. The system is shown to route a single photon with near-unity efficiency in an effective "weak-coupling" regime. Furthermore, two such nodes, forming a segment of a quantum network, are shown to perform several controlled quantum operations. All one-qubit operations involve a transfer of a photon from one cavity to another in a single node, while two-qubit operations involve transfer from one node to a next one, coupled via an optical fiber. Novel timing protocols for classical optical fields are found to simplify possible experimental realizations along with achievable effective parameter regime. Though our analysis here is restricted to a cavity-QED scenario, basic features of the model can be extended to various other physical systems including gated quantum dots, circuit-QED or opto-mechanical elements.