We propose a method of accelerating the speed of evolution of an open system by an external classical driving field for a qubit in a zero-temperature structured reservoir. It is shown that, with a judicious choice of the driving strength of the applied classical field, a speed-up evolution of an open system can be achieved in both the weak system-environment couplings and the strong system-environment couplings. By considering the relationship between non-Makovianity of environment and the classical field, we can drive the open system from the Markovian to the non-Markovian regime by manipulating the driving strength of classical field. That is the intrinsic physical reason that the classical field may induce the speed-up process. In addition, the roles of this classical field on the variation of quantum evolution speed in the whole decoherence process is discussed.Comment: 5 pages, 3 figures, comments welcom

We analyze the roles of initial correlations between the two-qubit system and a dissipative cavity on quantum discord dynamics of two qubits. Considering two initial system-cavity states, we show that the initial system-cavity correlations not only can initially increase the two-qubit quantum discord but also would lead to a larger long-time quantum discord asymptotic value. Moreover, quantum discord due to initial correlations is more robust than the case of the initial factorized state. Finally, we show the initial correlations' importance for dynamics behaviors of mutual information and classical correlation.

We consider the entanglement dynamics of N qubits interacting with independent structured reservoirs. The system is initially prepared in the multipartite Greenberger–Horne–Zeilinger (GHZ)-type state. We study the dependence of the entanglement dynamics on both the qubit number N and the purity of initial state, and show that the qubit number N and the purity can control the time of appearance of the N-qubit entanglement sudden death and the entanglement sudden birth of the reservoirs. Also based on the purity and the qubit number N, the revival of N-qubit entanglement does not necessarily indicate the disentanglement of reservoirs, and manifests before, simultaneously or even after the finite-time disentanglement of reservoirs.

In this paper, we propose a scheme to enhance trapping of entanglement of two qubits in the environment of a photonic band gap material. Our entanglement trapping promotion scheme makes use of combined weak measurements and quantum measurement reversals. The optimal promotion of entanglement trapping can be acquired with a reasonable finite success probability by adjusting measurement strengths.