Hidden Bell correlations in the four-level atom
arXiv:1601.06100
Abstract
We extend the Bell inequality known for two qubits to the four-level atom, including an artificial atom realized by the superconducting circuit, and qudit with j=3/2. We formulate the extended inequality as the inequality valid for an arbitrary Hermitian nonnegative 4x4-matrix with unit trace for both separable and entangled matrices.
10 pages, Based on the invited talk delivered by M.A. Man'ko at the 46th Winter Colloquium on the Physics of Quantum Electronics (PQE-2016, January 3--8, 2016, Snowbird, Utah, USA), to appear in Journal of Russian Laser Research, Vol. 37, issue 1 (2016)