Event-ready entangled photons from a solid-state single-photon source.

Solid-state emitters, such as semiconductor quantum dots, are a promising platform to develop single-photon sources. Recent breakthroughs in material syntheses and fabrication processes led to a new generation of devices, combining high emission brightness with near unity indistinguishable pure single-photon output [1]. These new generation single-photos sources are staring to enable experiments with multiple indistinguishable photons [2], a key step towards large-scale optical quantum technologies.

Here we employ a quantum dot source to demonstrate a 4-qubit Type-II Fusion Entangling Gate [4]. The Type-II Fusion Gate relies on the conditional detection of two ancillary qubits to generate entanglement between the two remaining qubits. We study the performance of this entangling gate as a function of the single-photon indistinguishability. We also discuss potential applications tor the Type-II fusion gate as an event-ready souce entangled photons.


[1] N. Somaschi, et al, “Near-optimal single-photon sources in the solid state” Nat. Phot. 10, 340 (2016)
[2] J. Loredo, J., et al, “Scalable performance in solid-state single photon sources”, Optica, 3, (2016).
[3] D. E. Browne, and T. Rudolph, “Resource-efficient linear optical quantum computation”, Phys. Rev. Lett. 95, 010501 (2005).