Proposal for Implementing Device-Independent Quantum Key Distribution based on a Heralded Qubit Amplification

Understand

In device-independent quantum key distribution (DIQKD), the violation of a Bell inequality is exploited to establish a shared key that is secure independently of the internal workings of the QKD devices.

• An experimental implementation of DIQKD, however, is still awaited, since hitherto all optical Bell tests are subject to the detection loophole, making the protocol unsecured.
• In particular, photon losses in the quantum channel represent a fundamental limitation for DIQKD.
• Here, we introduce a heralded qubit amplifier based on single-photon sources and linear optics that provides a realistic solution to overcome the problem of channel losses in Bell tests.