Artículos de revistas
A formalism for steering with local quantum measurements
Fecha
2018-08-01Registro en:
New Journal of Physics, v. 20, n. 8, 2018.
1367-2630
10.1088/1367-2630/aad8df
2-s2.0-85053112586
2-s2.0-85053112586.pdf
Autor
Perimeter Institute for Theoretical Physics
Universidade Federal do Rio de Janeiro (UFRJ)
Universidade Estadual Paulista (Unesp)
University of Strathclyde
University of Oxford
University of Bristol
Institución
Resumen
We develop a unified approach to classical, quantum and post-quantum steering. The framework is based on uncharacterised (black-box) parties performing quantum measurements on their share of a (possibly unphysical) quantum state, and its starting point is the characterisation of general no-signalling assemblages via non-positive local hidden-state models, which will be defined in this work. By developing a connection to entanglement witnesses, this formalism allows for new definitions of families of assemblages, in particular via (i) non-decomposable positive maps and (ii) unextendible product bases. The former proves to be useful for constructing post-quantum assemblages with the built-in feature of yielding only quantum correlations in Bell experiments, while the latter always gives certifiably post-quantum assemblages. Finally, our framework is equipped with an inherent quantifier of post-quantum steering, which we call the negativity of post-quantum steering. We postulate that post-quantum steering should not increase under one-way quantum operations from the steered parties to the steering parties, and we show that, in this sense, the negativity of post-quantum steering is a convex post-quantum-steering monotone.