The entanglement in quantum XY spin chains of arbitrary length is investigated via the geometric measure of entanglement. The emergence of entanglement is explained intuitively from the perspective of perturbations. The model is solved exactly and the energy spectrum is determined and analyzed in particular for the lowest two levels for both finite and infinite systems. The overlaps for these t...

In the present article we report the dynamical behavior of entanglement between π-electrons and photons in Graphene. It is shown that the degree of such entanglements depend on the orientation of π-electron momenta relative to the photonic polarization. Moreover, we show that as the detuning between the π-electron transition frequencies and that of the photons is increased, the degree of entang...

The quantum entanglements are studied in terms of the invariants under local unitary transformations. A generalized formula of concurrence for N -dimensional quantum systems is presented. This generalized concurrence has potential applications in studying separability and calculating entanglement of formation for high dimensional mixed quantum states. PACS numbers: 03.65.Bz, 89.70.+c SFB 256; B...

We study an entangled two-mode coherent state within the framework of2×2-dimensional Hilbert space. We investigate the problem of quantum teleportation ofa superposition coherent state via an entangled coherent channel. By three differentmeasures with the titles ``minimum assured fidelity (MASF)”, ``average teleportationfidelity” and ``optimal fidelity (f)” we study the ...

We discuss the degree of entanglement for symmetric passive optical networks. As a measure of the entanglement we use the information entropy and compare our results for a general number of inputs N with the known results for a two-mode beam-splitter. Special cases of interest are pointed out.

we study the dynamics of two three-level atoms interacting with independent bosonic lorentzian reservoirs at zero temperature. such systems can be created in far astronomical objects. quantum mechanical behaviour of these particles can produce detectable effects on the spectroscopic identifications of these objects, if such behaviour remain stable during the interaction with their media. it is ...

The most used states in continuous variable quantum information processing are Gaussian states, such as coherent states, squeezed states, or Einstein-Podolsky-Rosen like states [1]. The latter type of entangled states are two mode squeezed vacuum and represents a common source for most quantum communication protocols, such as quantum teleportation [2], quantum key distribution [3], quantum dens...

Entanglement plays an important role in quantum information processing and communication, such as quantum computation, secret sharing, teleportation, and quantum key distribution [1-3]. Over the last decade, characterizing or/and quantifying entanglement has been recognized as one of central tasks in quantum information science. Correspondingly, there have been many efforts in this direction, f...

We study the use of quantum entanglement in the zero-error source-channel coding problem. Here, Alice and Bob are connected by a noisy classical one-way channel, and are given correlated inputs from a random source. Their goal is for Bob to learn Alice’s input while using the channel as little as possible. In the zero-error regime, the optimal rates of source codes and channel codes are given b...

A spin gas is a natural extension of a classical gas. It consists of a large number of particles whose (random) motion is described classically, but, in addition, have internal (quantum mechanical) degrees of freedom that interact during collisions. For specific types of quantum interactions we determine the entanglement that occurs naturally in such systems. We analyze how the evolution of the...