Quantum discord quantifies nonclassical correlations in quantum states. We introduce discord for states in causal probabilistic theories, inspired by the original definition proposed by H. Ollivier and W. H. Zurek [Phys. Rev. Lett. 88, 017901 (2001)]. We show that the only probabilistic theory in which all states have null discord is classical probability theory. Non-null discord is then not ju...

A new measure based on the tripartite information diagram is proposed for identifying quantum discord in tripartite systems. The proposed measure generalizes the mutual information underlying discord from bipartite to tripartite systems, and utilizes both one-particle and two-particle projective measurements to reveal the characteristics of the tripartite quantum discord. The feasibility of the...

We propose DisCord, an opportunistic protocol for neighbor discovery and data exchange coordination in sensor networks. DisCord allows multiple low-end nodes within radio range to discover each other, self-organize into a network, and exchange data in an autonomous fashion. DisCord can successfully cope with node mobility and unstable network dynamics.

AIM To examine whether mothers' and fathers' levels of perceived relationship discord at childbirth were associated with postpartum depressive symptoms when the child was 3 months old. Another aim was to examine parents' levels of self-reported depressive symptoms. The hypothesis was that parents with high levels of perceived relationship discord have higher levels of postpartum depressive symp...

Quantum discord is the quantitative difference between two alternative expressions for bipartite mutual information, given respectively in terms of two distinct definitions for the conditional entropy. By constructing a stochastic model of shared states, classical discord can be similarly defined, quantifying the presence of some stochasticity in the measurement process. Therefore, discord can ...

Quantum state of composite system contains both classical and quantum correlation. Usually by quantum correlations one means quantum entanglement which provides an essential resource for quantum information processing such as quantum cryptography, dense coding, quantum computing [1, 2]. However, a quantum state of a composed system may contain other types of nonclassical correlation even if it ...

Quantum discord quantifies quantum correlation between quantum systems, which has potential application in quantum information processing. In this paper, we propose a scheme realizing the remote transfer of Gaussian quantum discord, in which another quantum discordant state or an Einstein-Podolsky-Rosen entangled state serves as ancillary state. The calculation shows that two independent optica...

In contrast with entanglement, as measured by concurrence, in general, quantum discord does not possess the property of monogamy; that is, there is no tradeoff between the quantum discord shared by a pair of subsystems and the quantum discord that both of them can share with a third party. Here, we show that, as far as monogamy is considered, quantum discord of pure states is equivalent to the ...

We study the level surfaces of quantum discord for a class of two-qubit states with parallel nonzero Bloch vectors. The dynamic behavior of quantum discord under decoherence is investigated. It is shown that a class of X states has sudden transition between classical and quantum correlations under decoherence. Our results include the ones in [Phys. Rev. Lett. 105. 150501] as a special case and ...

It is shown that the dissonance, a quantum correlation which is equal to quantum discord for separable state, is required for assisted optimal state discrimination. We find that only one side discord is required in the optimal process of assisted state discrimination, while another side discord and entanglement is not necessary. We show that the quantum discord, which is asymmetric depending on...