Entanglement of distant atoms by projective measurement: The role of detection efficiency

TL;DR

This paper compares different photon detection schemes for entangling distant atoms, analyzing how detection efficiency influences their success probability and fidelity, and identifies optimal protocols for various experimental conditions.

Contribution

It provides a detailed analysis of one-photon and two-photon entanglement schemes, including the impact of detection efficiency and the potential for combining protocols with purification.

Findings

One-photon schemes are more efficient at low detection efficiencies.

Two-photon schemes outperform at higher detection efficiencies.

Numerical examples based on current experiments illustrate the results.

Abstract

We assess proposals for entangling two distant atoms by measurement of emitted photons, analyzing how their performance depends on the photon detection efficiency. We consider schemes based on measurement of one or two photons and compare them in terms of the probability to obtain the detection event and of the conditional fidelity with which the desired entangled state is created. Based on an unravelling of the master equation, we quantify the parameter regimes in which one or the other scheme is more efficient, including the possible combination of the one-photon scheme with state purification. In general, protocols based on one-photon detection are more efficient in set-ups characterized by low photon detection efficiency, while at larger values two-photon protocols are preferable. We give numerical examples based on current experiments.