Einstein-Podolsky-Rosen steering: Closing the detection loophole with non-maximally-entangled states and arbitrary low efficiency

Quantum steering inequalities allow to demonstrate the presence of entanglement between two parties when one of the two measurement devices is not trusted. Here we show that quantum steering can be demonstrated for an arbitrary low detection efficiency by using two-qubit non-maximally-entangled states. Our result can have important applications in one-sided device-independent quantum key distribution. DOI: 10.1103/PhysRevA.87.020101