Photonic Controlled-Phase Gates Through Rydberg Blockade in Optical Cavities

TL;DR

This paper introduces a new method for implementing high-fidelity photonic controlled-phase gates using Rydberg blockade in optical cavities, enhancing quantum information processing and communication efficiency.

Contribution

The paper presents a novel scheme combining Rydberg blockade and optical cavities to realize efficient photonic quantum gates with moderate finesse cavities.

Findings

Enhanced optical non-linearity via Rydberg blockade in cavities

High-fidelity photonic controlled-phase gates demonstrated

Potential for improved quantum repeater communication rates

Abstract

We propose a novel scheme for high fidelity photonic controlled phase gates using Rydberg blockade in an ensemble of atoms in an optical cavity. The gate operation is obtained by first storing a photonic pulse in the ensemble and then scattering a second pulse from the cavity, resulting in a phase change depending on whether the first pulse contained a single photon. We show that the combination of Rydberg blockade and optical cavities effectively enhances the optical non-linearity created by the strong Rydberg interaction and thereby reduces the requirements for photonic quantum gates. The resulting gate can be implemented with cavities of moderate finesse which allows for highly efficient processing of quantum information encoded in photons. As a particular example of this, we show how the gate can be employed to increase the communication rate of quantum repeaters based on atomic ensembles.