Entanglement Swapping with Semiconductor-Generated Photons Violates Bell's Inequality

Phys Rev Lett. 2019 Oct 18;123(16):160502. doi: 10.1103/PhysRevLett.123.160502.

Abstract

Transferring entangled states between photon pairs is essential in quantum communication. Semiconductor quantum dots are the leading candidate for generating polarization-entangled photons deterministically. Here we show for the first time swapping of entangled states between two pairs of photons emitted by a single dot. A joint Bell measurement heralds the successful generation of the Bell state Ψ^{+}, yielding a fidelity of 0.81±0.04 and violating the CHSH and Bell inequalities. Our photon source matches atomic quantum memory frequencies, facilitating implementation of hybrid quantum repeaters.