Enhancement of quantum correlations for the system of cavity QED by applying bang-bang pulses

We propose a scheme of increasing quantum correlations for the cavity quantum electrodynamics system consisting of two noninteracting two-level atoms each locally interacting with its own quantized field mode by bang-bang pulses. We investigate the influence of the bang-bang pulses on the dynamics of quantum discord, entanglement, quantum mutual information and classical correlation between the two atoms. It is shown that the amount of quantum discord and entanglement of the two atoms can be improved by applying the bang-bang pulses.Comment: 6 pages, 5 figure

Robust stationary entanglement of two coupled qubits in independent environments

The dissipative dynamics of two interacting qubits coupled to independent reservoirs at nonzero temperatures is investigated, paying special attention to the entanglement evolution. The counter-rotating terms in the qubit-qubit interaction give rise to stationary entanglement, traceable back to the ground state structure. The robustness of this entanglement against thermal noise is thoroughly analyzed, establishing that it can be detected at reasonable experimental temperatures. Some effects linked to a possible reservoir asymmetry are brought to light.Comment: 8 pages, 6 figures; version accepted for publication on Eur. Phys. J.

Sudden Death of Entanglement of Two Jaynes-Cummings Atoms

We investigate entanglement dynamics of two isolated atoms, each in its own Jaynes-Cummings cavity. We show analytically that initial entanglement has an interesting subsequent time evolution, including the so-called sudden death effect.Comment: 3 pages, 3 figure

Modulated Entanglement Evolution Via Correlated Noises

We study entanglement dynamics in the presence of correlated environmental noises. Specifically, we investigate the quantum entanglement dynamics of two spins in the presence of correlated classical white noises, deriving Markov master equation and obtaining explicit solutions for several interesting classes of initial states including Bell states and X form density matrices. We show how entanglement can be enhanced or reduced by the correlation between the two participating noises.Comment: 9 pages, 4 figures. To be published in Quantum Information Processing, special issue on Quantum Decoherence and Entanglemen