Ioannis Kogias

TL;DR: A computable measure of steering for arbitrary bipartite Gaussian states of continuous variable systems is introduced, which reduces to a form of coherent information, which is proven never to exceed entanglement, and to reduce to it on pure states.

TL;DR: This work establishes an unconditional security proof for entanglement-based continuous-variable quantum secret sharing schemes, in the limit of asymptotic keys and for an arbitrary number of players, and demonstrates theoretically the feasibility of the scheme, which can be implemented by Gaussian states and homodyne measurements, with no need for ideal single-photon sources or quantum memories.

TL;DR: It is proved that a monogamy relation akin to the generalized Coffman-Kundu-Wootters inequality holds quantitatively for a recently introduced measure of Gaussian steering, which pin down the role of multipartite steering for quantum communication.

TL;DR: This work provides a hierarchy of sufficient conditions for the steerability of bipartite quantum states of any dimension, including continuous variable states, and provides a systematic framework to analytically derive nonlinear steering criteria.

TL;DR: In this article, a steering measure based on the violation of an optimized variance test for the EPR paradox by quadrature measurements is proposed, which admits a computable and experimentally friendly lower bound only depending on the second moments of the state, which reduces to a quantifier of steerability by Gaussian measurements.