All our former experience with application of quantum theory seems to say: what is predicted by quantum formalism must occur in laboratory. But the essence of quantum formalism — entanglement, recognized by Einstein, Podolsky, Rosen and Schrödinger — waited over 70 years to enter to laboratories as a new resource as real as energy. This holistic property of compound quantum systems, which invol...

This essay considers the question of the ontology of relativistic quantum field theory (RQFT). It aims to discuss possible implications of the peculiarities of quantum entanglement and quantum non-locality within the algebraic approach to RQFT. Fundamental results such as the Reeh-Schlieder theorem do not only show that quantum entanglement is a truly central feature of RQFT, but also that quan...

In the present work, we investigate the quantum thermal entanglement in molecular magnets composed of dimers of spin S, using an Entanglement Witness built from measurements of magnetic susceptibility. An entanglement temperature, Te, is then obtained for some values of spin S. From this, it is shown that Te is proportional to the intradimer exchange interaction J and that entanglement appears ...

We consider a variation of the multi-party communication complexity scenario where the parties are supplied with an extra resource: particles in an entangled quantum state. We show that, although a prior quantum entanglement cannot be used to simulate a communication channel, it can reduce the communication complexity of functions in some cases. Specifically, we show that, for a particular func...

The entanglement between a ?-type three-level atom and its spontaneous emission fields is investigated. The effect of spontaneously generated coherence (SGC) on entanglement between the atom and its spontaneous emission fields is then discussed. We find that in the presence of SGC the entanglement between the atom and its spontaneous emission fields is completely phase dependent, while in absen...

Entanglement is a kind of nonlocal correlation that only exists in quantum systems. Recent studies on entanglement have been motivated by its potential applications in quantum computation, quantum teleportation and quantum communication. As the spin system is perfect to realize the quantum computer, many efforts focus on the entanglement in the Heisenberg spin model, Ising model in a transverse...

In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the continuous-variable quantum entanglement and quantum discord for a system consisting of two non-interacting modes embedded in a thermal environment. Entanglement and discord are used to quantify the quantum correlations of the system. For all values of the tempe...

Entanglement is an essential resource in current experimental implementations for quantum information processing. We review a class of experiments exploiting photonic entanglement, ranging from one-way quantum computing over quantum communication complexity to long-distance quantum communication. We then propose a set of feasible experiments that will underline the advantages of photonic entang...

The non-classical nature of quantum entanglement is a key ingredient in the rapidly developing science of quantum information. One of the important tasks involved is quantifying quantum entanglement, which is essential in assessing the performance of a quantum system in several applications such as quantum teleportation, quantum cryptography, quantum computation and quantum communication There ...

Entanglement is a non local property of quantum states which has no classical counterpart and plays a decisive role in quantum information theory. Several protocols, like the teleportation, are based on quantum entangled states. Moreover, any quantum algorithm which does not create entanglement can be efficiently simulated on a classical computer. The exact role of the entanglement is neverthel...