we study the dynamics of two three-level atoms interacting with independent bosonic lorentzian reservoirs at zero temperature. such systems can be created in far astronomical objects. quantum mechanical behaviour of these particles can produce detectable effects on the spectroscopic identifications of these objects, if such behaviour remain stable during the interaction with their media. it is ...

In the present work, we consider a scenario where an arbitrary two-qubit pure state is applied for the quantum key generation (QKG). Using the twirling procedure to convert the pure state into a Werner state, the error rate of the key can be reduced by a factor of 2/3. This effect indicates that entanglement is not the sufficient resource of QKG protocol since it is not increased in the twirlin...

Quantum entanglement and quantum nonlocality are known to exhibit monogamy; that is, they obey strong constraints on how they can be distributed among multipartite systems. Quantum correlations that comprise and go beyond entanglement are quantified by, e.g., quantum discord. It was observed recently that for some states quantum discord is not monogamous. We prove, in general, that any measure ...

Quantum discord is a measure of the quantumness of correlations. After reviewing its different versions and properties, we apply it to the questions of quantum information processing. First we show that changes in discord in the processed unentangled states indicate the need for entanglement in the distributed implementation of quantum gates. On the other hand, it was shown that zero system-env...

In quantum information theory, discord has been proposed as a tool to characterise the presence of "quantum correlations" between subparts given system. Whether system behaves quantum-mechanically or classically is believed be impacted by phenomenon decoherence, which originates from unavoidable interaction this and an environment. Generically, decoherence associated with decrease state purity,...

In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the continuous-variable quantum correlations (quantum entanglement and quantum discord) for a system consisting of two noninteracting bosonic modes embedded in a thermal environment. We solve the Kossakowski-Lindblad master equation for the time evolution of the con...

We present an analytical solution for classical correlation, defined in terms of linear entropy, in an arbitrary system when the second subsystem is measured. We show that the optimal measurements used in the maximization of the classical correlation in terms of linear entropy, when used to calculate the quantum discord in terms of von Neumann entropy, result in a tight upper bound for arbitrar...

This study examined the associations between the quality of adolescents’ peer and family relationships and the quality of their young adult romantic relationships. Adolescents (N = 253) completed self-report measures of their family and peer relationships in grades 10–12; 7 years later, they reported on connectedness, discord, and the confl ict tactics used by both partners in their current rom...