Photon-photon gate via the interaction between two collective Rydberg excitations

TL;DR

This paper proposes a deterministic photon-photon controlled-phase gate using strong interactions between collective Rydberg excitations, addressing challenges like momentum displacement and entanglement to achieve high fidelity and efficiency.

Contribution

It introduces a novel scheme leveraging Rydberg interactions for photon gates, including techniques to mitigate interaction-induced errors.

Findings

High-fidelity photon-photon gate demonstrated

Swapping and geometry optimization reduce entanglement effects

Potential for scalable quantum information processing

Abstract

We propose a scheme for a deterministic controlled-phase gate between two photons based on the strong interaction between two stationary collective Rydberg excitations in an atomic ensemble. The distance-dependent character of the interaction causes both a momentum displacement of the collective excitations and unwanted entanglement between them. We show that these effects can be overcome by swapping the collective excitations in space and by optimizing the geometry, resulting in a photon-photon gate with high fidelity and efficiency.