MATERA Juan Mauricio
Measurements, quantum discord, and parity in spin-1 systems
ROSSIGNOLI, R. D.; MATERA, JUAN MAURICIO; CANOSA, NORMA
PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS
AMER PHYSICAL SOC
Lugar: New York; Año: 2012 vol. 86 p. 22104 - 22104
We consider the evaluation of the quantum discord and other related measures of quantum correlations in a system formed by a spin-1 and a complementary spin system. A characterization of general projective measurements in such system in terms of spin averages is thereby introduced, which allows one to easily visualize their deviation from standard spin measurements. It is shown that the measurement optimizing these measures corresponds in general to a nonspin measurement. The important case of states that commute with the total Sz spin-parity is discussed in detail, and the general stationary measurements for such states (parity preserving measurements) are identified. Numerical and analytical results for the quantum discord, the geometric discord, and the one way information deficit in the relevant case of a mixture of two aligned spin-1 states are also presented.