Certifying the presence of a photonic qubit by splitting it in two

Abstract

We present an implementation of photonic qubit precertification that performs the delicate task of detecting the presence of a flying photon without destroying its qubit state, allowing loss-sensitive quantum cryptography and tests of nonlocality even over long distance. By splitting an incoming single photon in two via parametric down-conversion, we herald the photon's arrival from an independent photon source while preserving its quantum information with up to $92.3\pm 0.6$ % fidelity. With reduced detector dark counts, precertification will be immediately useful in quantum communication.

6 pages, 6 figures, updated to published version

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Cited by in corpus (13)

• Photonic quantum information processing: a concise review
• Device-Independent Quantum Key Distribution with Random Key Basis
• Nondestructive detection of photonic qubits
• Heralded quantum steering over a high-loss channel
• Highly efficient visible and near-IR photon pair generation with thin-film lithium niobate
• Graph-theoretic approach to Bell experiments with low detection efficiency
• Conservation of angular momentum on a single-photon level
• Long-distance entanglement sharing using hybrid states of discrete and continuous variables
• Quantum channel correction outperforming direct transmission
• Amplification of cascaded downconversion by reusing photons with a switchable cavity
• Coincidence postselection for genuine multipartite nonlocality: Causal diagrams and threshold efficiencies
• A Tractable Protocol for Detection-Loophole-Free Bell Tests over Long Distances
• Low-noise heralded single photons from cascaded downconversion