One of the defining differences between classical and quantum systems is how measurements affect them. Here, we compare approaches contextuality discord in capturing correlations special classes two-qubit states, demonstrating that although non-discordant states are non-contextual, discordant not always contextual.

Deterministic quantum computation with one pure qubit (DQC1) is an efficient model of computation that uses highly mixed states. Unlike pure-state models, its power is not derived from the generation of a large amount of entanglement. Instead it has been proposed that other nonclassical correlations are responsible for the computational speedup, and that these can be captured by the quantum dis...

A quantitative estimation of quantum discord is performed for a Heisenberg spin 1/2 dimer compound (NH4CuPO4, H2O) by means of experimental magnetic and thermal measurements. Magnetic susceptibility and specific heat data were collected for NH4CuPO4, H2O and analyzed within the framework of the Heisenberg isolated dimer model. Internal energy as a function of temperature is obtained by integrat...

This paper reviews two well-studied measures of quantum correlations which exist between the subsystems that consists the most simple composite systems (bipartite systems). The first one is Entanglement of Formation (EoF) and quantifies the entanglement while the second one, the quantum discord (QD), is a measure of all quantum correlations of the bipartite system. Here the theoretical backgrou...

We introduce the discording power of a unitary transformation, which assesses its capability to produce quantum discord, and analyze in detail the generation of discord by relevant classes of two-qubit gates. Our measure is based on the Cartan decomposition of two-qubit unitaries and on evaluating the maximum discord achievable by a unitary upon acting on classical-classical states at fixed pur...

We consider two celebrated criteria for defining the nonclassicality of bipartite bosonic quantum systems, the first stemming from information theoretic concepts and the second from physical constraints on the quantum phase space. Consequently, two sets of allegedly classical states are singled out: (i) the set C composed of the so-called classical-classical (CC) states-separable states that ar...

Quantum discord as a measure of the quantum correlations cannot be easily computed for most of density operators. In this paper, we present a measure of the total quantum correlations that is operationally simple and can be computed effectively for an arbitrarymixed state of amultipartite system.Themeasure is based on the coherence vector of the party whose quantumness is investigated as well a...

We consider the phenomenon of mutual synchronization in a fundamental quantum system of two detuned quantum harmonic oscillators dissipating into the environment. We identify the conditions leading to this spontaneous phenomenon, showing that the ability of the system to synchronize is related to the existence of disparate decay rates and is accompanied by robust quantum discord and mutual info...

The last two decades have witnessed a rapid development of quantum information processing, a new paradigm which studies the power and limit of “quantum advantages” in various information processing tasks. Problems such as when quantum advantage exists, and if existing, how much it could be, are at a central position of these studies. In a broad class of scenarios, there are, implicitly or expli...

Characterization of the correlations of a multiparticle system remains an open problem. We generalize the notion of quantum discord, using multivariate mutual information, to characterize the quantum properties of a multiparticle system. This new measure, called dissension, is a set of numbers – quantumness vector. There are a number of different possible generalizations. We consider two of the...