Negativity and quantum discord in Davies environments

Abstract

We investigate the time evolution of negativity and quantum discord for a pair of non-interacting qubits with one being weakly coupled to a decohering Davies-type Markovian environment. At initial time of preparation, the qubits are prepared in one of the maximally entangled pure Bell states. In the limiting case of pure decoherence (i.e. pure dephasing), both, the quantum discord and negativity decay to zero in the long time limit. In presence of a manifest dissipative dynamics, the entanglement negativity undergoes a sudden death at finite time while the quantum discord relaxes continuously to zero with increasing time. We find that in dephasing environments the decay of the negativity is more propitious with increasing time; in contrast, the evolving decay of the quantum discord proceeds weaker for dissipative environments. Particularly, the slowest decay of the quantum discord emerges when the energy relaxation time matches the dephasing time.

Temperature-independent teleportation of qubits in Davies environments

“…There are two origins of temperature dependence of the Davis maps Eqs. (8)(9)(10)(11). The first is explicit, via parameter p in Eq.…”

“…They satisfy most of the desired thermodynamic and statistical-mechanical properties such as the detailed balance condition [1]. Davies approximation has recently been applied to studies of various problems in quantum information and physics of open quantum systems including entanglement dynamics [14], quantum discord [7,10], or properties of geometric phases of qubits [8].…”

Payoffs and Coherence of a Quantum Two-Player Game in a Thermal Environment

“…Such a description is most general when applied to Markovian open systems weakly coupled to the thermal bath. We consider the most natural quantifier studied in the context of game theory: the difference between payoffs of players Equation (35). We show that there are at least two aspects of the influence of the Davies bath on the results of the game.…”

“…with partition function Z = Tre −βH and with inverse temperature β. Davies approximation has been successfully used in studies of various problems in quantum information and physics of open quantum systems, including entanglement dynamics [33,34], quantum discord [35] or properties of geometric phases of qubits [36] and the thermodynamic properties of nano-systems [37]. The main properties of the Davies semigroups is that the unitary part and the dissipative part decouples, and in equilibrium, transition rates between eigenstates of Hamiltonian H obey a micro-reversibility condition, i.e., the transition in one direction is exactly balanced from the opposite one.…”

Quantum Correlations in Qutrit-Qutrit Systems under Local Quantum Noise Channels

“…It can be computed easily for arbitrary states of a composite system. Therefore, it has received various studies [6][7][8][9][10]. However, quantum entanglement does not account for all of the non-classical properties of quantum phenomenons.…”