We consider entanglement for quantum states defined in vector spaces over the real numbers. Such real entanglement is different from entanglement in standard quantum mechanics over the complex numbers. The differences provide insight into the nature of entanglement in standard quantum theory. Wootters [Phys. Rev. Lett. 80, 2245 (1998)] has given an explicit formula for the entanglement of forma...

In this paper the the effect of Dzyaloshinskii-Moriya interaction and anisotropy on the Entanglement of Heisenberg chain has been studied. While the anisotropy suppress the entanglement due to favoring of the alignment of spins, the DM interaction restores the spoiled entanglement via creation of the quantum fluctuations. Thermodynamic limit of the model and emerging of nonanalytic behavior of ...

The relation is studied between the entanglement production and collective radiation by an ensemble of atoms. Entanglement production is quantified by means of a general measure introduced earlier by the author. Primary emphasis is placed on the entanglement generated by pseudospin density matrices. The problem of collective atomic radiation can be described by the pseudospin evolution equation...

We consider entanglement for quantum states defined in vector spaces over the real numbers. Such real entanglement is different from entanglement in standard quantum mechanics over the complex numbers. The differences provide insight into the nature of entanglement in standard quantum theory. Wootters [Phys. Rev. Lett. 80, 2245 (1998)] has given an explicit formula for the entanglement of forma...

| Quantum computers are believed to surpass their classical counterparts in speed-up and efficiency. However, the origin of this speed-up in quantum algorithms is not yet fully understood. There are indications that entanglement plays an important role in quantum computation. Quantum algorithms that do not involve entanglement appear to require an exponential amount of resources and may be effi...

We study the loss of entanglement of a bipartite state subjected to discarding or measurement of one qubit. Examining behavior of different entanglement measures, we find that entanglement of formation, entanglement cost, logarithmic negativity, and one-way distillable entanglement are lockable measures in that they can decrease arbitrarily after measuring one qubit. We prove that any convex an...

there are many claims that quantum mechanics plays a key role in the origin and/or operation of biological organisms. the mechanism of the meiosis, mitosis and gametes life cycle from the view-point of quantum for human has been represented. the quantum gates have been used to simulate these processes for the first time. the reason of several hundred sperms has been explained in the male too

We study the exact entanglement dynamics of two qubits in a common structured reservoir. We demonstrate that for certain classes of entangled states, entanglement sudden death occurs, while for certain initially factorized states, entanglement sudden birth takes place. The backaction of the non-Markovian reservoir is responsible for revivals of entanglement after sudden death has occurred, and ...

Quantum entanglement is an important prediction of quantum mechanics and constitutes indeed a valuable resource in quantum information processing [1]. Much efforts are devoted to the study and characterization of it. Very recently one kind of natural entanglement, the thermal entanglement [2–7], is proposed and investigated. The investigations of this type of entanglement, groundstate entanglem...

In this chapter we review the characterization of entanglement in Gaus-sian states of continuous variable systems. For two-mode Gaussian states, we discuss how their bipartite entanglement can be accurately quantified in terms of the global and local amounts of mixedness, and efficiently estimated by direct measurements of the associated purities. For multimode Gaussian states endowed with loca...