Generalized entropic measures of quantum correlations

R. ROSSIGNOLI; N. CANOSA; L. CILIBERTI

Foz do Iguazu

Conferencia; XII International Conference on Squeezed States and Uncertainty Relations(ICCSUR); 2011

UNICAN - UFScar -UnB

The exponential speedup achieved in certain quantum algorithms based on mixed states with negligible entanglement has renewed the interest on alternative measures of quantum correlations for mixed states. In this contribution we discuss a general measure of non-classical correlations for bipartite systems based on generalized entropic functions, defined as the minimum information loss due to a local measurement. In the case of pure states it reduces to the generalized entanglement entropy, i.e., to the generalized entropy of the reduced state. However, in the case of mixed states it can be nonzero in separable states, vanishing just for states diagonal in a general product basis, like the quantum discord. Simple quadratic measures of quantum correlations arise as a particular case of the present formalism. The minimum information loss due to a joint local measurement is also considered. The evaluation of these measures in some relevant cases will also be discussed, together with comparison with the corresponding entanglement monotones.