Heralded entangling quantum gate via cavity-assisted photon scattering

TL;DR

This paper proposes simple, high-probability heralded entanglement generation protocols between atoms via cavity-assisted photon scattering, applicable to remote atoms and atomic clouds, advancing quantum networking capabilities.

Contribution

It introduces a novel single-step parallel quantum circuit for entangling remote atoms, improving upon traditional serial methods and enabling applications in quantum networks.

Findings

High entanglement degree with near-unity success probability.

Protocols applicable to remote atoms and atomic clouds.

Potential for quantum state transfer, teleportation, and nonlocal quantum memory.

Abstract

We theoretically investigate the generation of heralded entanglement between two identical atoms via cavity-assisted photon scattering in two different configurations, namely either both atoms confined in the same cavity or trapped into locally separated ones. Our protocols are given by a very simple and elegant single-step process, whose key mechanism is a controlled-phase-flip gate implemented by impinging a single photon on single-sided cavities. In particular, when the atoms are localized in remote cavities, we introduce a single-step parallel quantum circuit instead of the serial process extensively adopted in the literature. We also show that such parallel circuit can be straightforwardly applied to entangle two macroscopic clouds of atoms. Both protocols proposed here predict a high entanglement degree with a success probability close to the unity for the state-of-the-art parameters. Among other applications, our proposal and its extension to multiple atom-cavity systems step toward a suitable route for quantum networking, in particular for quantum state transfer, quantum teleportation and nonlocal quantum memory.