Post-selection boosts quantum key rate, researchers find

The team implemented a source-independent quantum key distribution protocol between two nodes, evaluating whether correlated photons can support secure communication as a key component of future quantum repeaters. Their work employs a deterministic photon source, a strain-tuned GaAs quantum dot within a photonic cavity, and shows high-resolution temporal post-selection enables secure key exchange, with potential for further improvements. Researchers achieved this improvement using photons originating from a single, deterministic source, a strain-tuned gallium arsenide (GaAs) quantum dot embedded within a photonic cavity. The team’s experimental setup involved exciting the quantum dot twice, generating sequential entangled photon pairs with a 1.6 nanosecond delay between pulses. Central to the experiment was a Bell state measurement (BSM) setup, achieving 50% efficiency, where two photons from the sequentially generated pairs interfered. The outcome…