12-photon entanglement and scalable scattershot boson sampling with optimal entangled-photon pairs from parametric down-conversion

TL;DR

This paper presents a highly efficient entangled photon source enabling the generation of 12-photon entanglement and scalable scattershot boson sampling, advancing photonic quantum technology capabilities.

Contribution

The authors develop a near-unity heralding efficiency and indistinguishability SPDC source, achieving the first 12-photon entanglement and demonstrating scalable boson sampling with significantly increased count rates.

Findings

Achieved ~97% heralding efficiency and ~96% indistinguishability in SPDC source.

Generated 12-photon genuine entanglement with fidelity of 0.572.

Enabled scattershot boson sampling with count rates over four orders of magnitude higher.

Abstract

Entangled photon sources with simultaneously near-unity heralding efficiency and indistinguishability are the fundamental elements for scalable photonic quantum technologies. We design and realize a degenerate entangled-photon source from an ultrafast pulsed laser pumped spontaneous parametric down-conversion (SPDC), which show simultaneously ~97% heralding efficiency and ~96% indistinguishability between independent single photons. Such a high-efficiency and frequency-uncorrelated SPDC source allows generation of the first 12-photon genuine entanglement with a state fidelity of 0.572(24). We further demonstrate a blueprint of scalable scattershot boson sampling using 12 SPDC sources and a 12*12-modes interferometer for three-, four-, and five-boson sampling, which yields count rates more than four orders of magnitudes higher than all previous SPDC experiments. Our work immediately enables high-efficiency implementations of multiplexing, scattershot boson sampling, and heralded creation of remotely entangled photons, opening up a promising pathway to scalable photonic quantum technologies.