Device-independent verification of Einstein-Podolsky-Rosen steering

Abstract

If the presence of entanglement could be certified in a device-independent (DI) way, it is likely to provide various quantum information processing tasks with unconditional security. Recently, it was shown that a DI protocol, combining measurement-device-independent techniques with selftesting, is able to verify all entangled states, however, it imposes demanding requirements on its practical implementation. Here, we present a less-demanding protocol based on Einstein-Podolsky-Rosen (EPR) steering, which is achievable with current technology. Particularly, we first establish a complete framework for DI verification of EPR steering and show that all steerable states can be verified. Then, we analyze the three-measurement setting case, allowing for imperfections of self-testing. Finally, a four-photon experiment is implemented to device-independently verify EPR steering and to further demonstrate that even Bell local states can be faithfully verified. Our findings pave the way for realistic applications of secure quantum information tasks.

Self-testing of any pure entangled state with minimal number of measurements and optimal randomness certification in one-sided device-independent scenario

“…Then, a related question is whether one can make our self-testing scheme fully device-independent by taking inspiration from Refs. [30,31]. Precisely, one can for instance imagine a three-partite scenario in which Alice together with Charlie perform a Bell test to deviceindependently certify the measurements that Alice's measuring device performs.…”