A general framework to define entropic measures of quantum discord-like correlations

G. BELLOMO; G. M. BOSYK; F. HOLIK; P. W. LAMBERTI; M. PORTESI; S. ZOZOR

Cágliari

Seminario; Seminario de la Università degli Studi di Cagliari; 2016

Quantum correlations lie at the heart of the difference between the classical and the quantum worlds. Beyond the popular entanglement-separability paradigm, there is a bunch of novel measures that have been proposed and studied during the last twenty years. Among them, quantum discord, which is a measure closely related to the idea that quantum systems cannot be accessed without any kind of disturbance, has attracted a lot of attention due to its relevance in several computational protocols, as well as for its main role on the interpretation of decoherence processes. In this talk, I will present the essential formalism concerning this disturbance-based measures of quantum correlations in order to discuss how to obtain a family of quantum correlation measures by using general entropic forms, namely (q,s)-entropies (or unified entropies). Moreover, I will explain a general strategy to avoid a problem that comes out when using nonadditive entropies to define this kind of measures.