Necessary conditions for steerability of two qubits, from consideration of local operations. (arXiv:1906.04693v1 [quant-ph])

EPR-steering refers to the ability of one observer to convince a distant
observer that they share entanglement by making local measurements. Determining
which states allow a demonstration of EPR-steering remains an open problem in
general, even for the simplest case of two qubits. Here, we outline and
demonstrate a method of constructing new classes of two-qubit states which are
non-steerable by arbitrary projective measurements, from consideration of local
operations performed by the steering party on states known to be non-steerable.

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