Robust-fidelity atom-photon entangling gates in the weak-coupling regime

TL;DR

This paper presents a robust entangling scheme for atom-photon interactions in weak-coupling regimes, utilizing photon scattering in waveguides that converts various imperfections into heralded losses, enabling high-fidelity quantum gates.

Contribution

The authors introduce a simple, error-resilient entangling method based on photon scattering that effectively handles imperfections and works in the weak-coupling regime.

Findings

Automatically converts imperfections into heralded losses

Enables high-fidelity entangling gates in weak-coupling regimes

Facilitates atom-photon interfaces and measurement-based quantum computing

Abstract

We describe a simple entangling principle based on the scattering of photons off single emitters in one-dimensional waveguides (or extremely-lossy cavities). The scheme can be applied to photonic qubits encoded in polarization or time-bin, and features a filtering mechanism that works effectively as a built-in error-correction directive. This automatically maps imperfections from weak couplings, atomic decay into undesired modes, frequency mismatches, or finite bandwidths of the incident photonic pulses, into heralded losses instead of infidelities. The scheme is thus adequate for high-fidelity maximally entangling gates even in the weak-coupling regime. These, in turn, can be directly applied to store and retrieve photonic-qubit states, thereby completing an atom-photon interface toolbox, or to sequential measurement-based quantum computations with atomic memories.