Measurement-device-independent and arbitrarily loss-tolerant verification of quantum steering
InU Jeon, Hyunseok Jeong · Physical Review A · 2019
We propose a method to verify quantum steering for two-qubit states with an arbitrary amount of null results when both the steering and steered parties cannot be trusted. We converted the steering inequality proposed in a recent article [Phys. Rev. X 2, 031003 (2012)] to a corresponding measurement-device-independent steering criterion that depends on the heralding efficiency of the steering party, number of measurement settings, and imperfection of the state preparation. As a result, for a relative frequency of valid measurement outcomes ${\ensuremath{\eta}}_{h}$, the steering can be verified using a number of different measurement settings larger than $1/{\ensuremath{\eta}}_{h}$ and maximally entangled states. Furthermore, steerability is guaranteed as long as the measurement efficiency of the steered party is nonzero. Our result is useful for loss-tolerant and measurement-device-independent steering tasks.