We present a detailed study of the entanglement dynamics of a two-qubit system coupled to independent non-Markovian environments, employing hierarchy equations. This recently developed theoretical treatment can conveniently solve non-Markovian problems. We concentrate on calculating the death...

The entanglement properties of the SU(1,1)-related coherent fields interacting with a moving atom via the two-photon transition are investigated. We discuss the quantum entanglement between the SU(1,1)-related coherent fields and the moving atom by using the quantum reduced entropy and that...

We propose a new method to understand quantum entanglement using the thermo field dynamics (TFD) described by a double Hilbert space. The entanglement states show a quantum-mechanically complicated behavior. Our new method using TFD makes it easy to understand the entanglement states, because...

We discuss a general formalism for the inference of quantum density operators from incomplete information, based on the maximization of general non-additive entropic forms, and its application to the reconstruction of mixed states of composite quantum systems from generalized Bell measurements....

In this paper a novel scheme is proposed where with the help of Victor (a state preparer) an unknown EPR pair is copied in a certain probability so that three parties of communication can obtain the EPR state, respectively. The first stage of this scheme is to teleport an unknown EPR state to...