An entangling quantum-logic gate operated with an ultrabright single photon-source

摘要

We demonstrate unambiguous entangling operation of a photonic quantum-logicgate driven by an ultrabright solid-state single-photon source.Indistinguishable single photons emitted by a single semiconductor quantum dotin a micropillar optical cavity are used as target and control qubits. For asource brightness of 0.56 collected photons-per-pulse, the measured truth tablehas an overlap with the ideal case of 68.4%, increasing to 73.0% for a sourcebrightness of 0.17 photons- per-pulse. The gate is entangling: at a sourcebrightness of 0.48, the Bell-state fidelity is above the entangling thresholdof 50%, and reaches 71.0% for a source brightness of 0.15.