Shubhayan Sarkar (CTP PAS): Certification of quantum systems using quantum steering

Quantum Information and Quantum Computing Seminars CTP PAS 2021-10-27

Device-independent certification schemes have gained a lot of interest lately. In this regard, we explore quantum steering for certifying higher-dimensional quantum systems in a one-sided device-independent way. In the first part of the talk, I would discuss our proposal of a one-sided device-independent protocol that could certify any set of d-outcome projective measurements which do not share any common invariant subspace which we termed as “genuinely incompatible measurements” which includes mutually unbiased bases which are an important resource for quantum cryptography. We also find the robustness of our protocol for a class of mutually unbiased bases towards experimental imperfections. In the second part of the talk, I would discuss our proposal of a one-sided device-independent protocol that could certify any bipartite entangled state using a minimal number of measurements possible, that is, two per subsystem. Using the certified state, we were able to certify every extremal POVM which in turn can be used to certify randomness of amount 2logd bits, which is the maximum amount that can be achieved using quantum systems of dimension d.