The Retarding Effect of Noise on Entanglement Sudden Death

T. Yu, Joseph H. Eberly

K. O. Yashodamma, P. J. Geetha, Sudha

苏晓龙

Qurrat-ul-Ain Gulfam, Z. Ficek, Jörg Evers

The role of retardation in the entanglement dynamics of two distant atoms interacting with a multimode field of a ring cavity is discussed. The retardation is associated with a finite time required for light to travel between the atoms located at a finite distance and between the atoms and the cavity boundaries. We explore features in the concurrence indicative of retardation and show how these features evolve depending on the initial state of the system, distance between the atoms, and the number of modes to which the atoms are coupled. In particular, we consider the short-time and the long-time dynamics for both the multi- and subwavelength distances between the atoms. It is found that the retardation effects can qualitatively modify the entanglement dynamics of the atoms not only at multi- but also at subwavelength distances. We follow the temporal evolution of the concurrence and find that at short times of the evolution the retardation induces periodic sudden changes of entanglement. To analyze where the entanglement lies in the space spanned by the state vectors of the system, we introduce the collective Dicke states of the atomic system that explicitly account for the sudden changes as a periodic excitation of the atomic system to the maximally entangled symmetric state. At long times, the retardation gives rise to periodic beats in the concurrence that resemble the phenomenon of collapses and revivals in the Jaynes-Cummings model. In addition, we identify parameter values and initial conditions at which the atoms remain separable or are entangled without retardation during the entire evolution time, but exhibit the phenomena of sudden birth and sudden death of entanglement when the retardation is included.

H. T. Cui, Kai Li, X. X. Yi

Muhammad Asif Ramzan

Entanglement dynamics of a qutrit-qutrit system under the influence of global, local and multilocal decoherence introduced by phase flip, trit flip and trit phase flip channels is investigated. The negativity and realignment criterion are used to quantify the entanglement of the system. It is shown that the entanglement sudden death and distibility sudden death can be avoided in the presence of phase flip, trit flip and trit-phase flip environments. It is shown that certain free entangled distillable qutrit states become bound entangled or separable i.e. convert into non-distillable states under different flipping noises. It is also seen that local operations do not have any effect on the entanglement dynamics of the system. Further more, no ESD and DSD is seen for the case of trit flip channel.