The single-copy entanglement of a given many-body quantum system is defined [J. Eisert and M. Cramer, Phys. Rev. A 72, 042112 (2005)10.1103/PhysRevA.72.042112] as the maximal entanglement deterministically distillable from a bipartition of a single specimen of that system. For critical (gapless) spin chains, it was recently shown that this is exactly half the von Neumann entropy [R. Orús, J. I....

If two separated observers are supplied with entanglement, in the form of n pairs of particles in identical partly-entangled pure states, one member of each pair being given to each observer; they can, by local actions of each observer, concentrate this entanglement into a smaller number of maximally-entangled pairs of particles, for example EinsteinPodolsky-Rosen singlets, similarly shared bet...

Squeezing of quantum fluctuations by means of entanglement is a well-recognized goal in the field of quantum information science and precision measurements. In particular, squeezing the fluctuations via entanglement between 2-level atoms can improve the precision of sensing, clocks, metrology, and spectroscopy. Here, we demonstrate 3.4 dB of metrologically relevant squeezing and entanglement fo...

If two separated observers are supplied with entanglement, in the form of n pairs of particles in identical partly-entangled pure states, one member of each pair being given to each observer; they can, by local actions of each observer, concentrate this entanglement into a smaller number of maximally-entangled pairs of particles, for example EinsteinPodolsky-Rosen singlets, similarly shared bet...

Entanglement is an amazing feature of quantum mechanics which is a nontrivial non-local correlation between states. It is studied and exploited greatly in the field of quantum information. Traditionally, most quantum systems of interest in quantum information is described by discrete variable states, e.g. spin of particles. Thus, entanglement is studied to a considerable extent in such state. N...

The entanglement of pair cat states in the phase damping channel is studied by employing the relative entropy of entanglement. It is shown that the pair cat states can always be distillable in the phase damping channel. Furthermore, we analyze the fidelity of teleportation for the pair cat states by using joint measurements of the photon-number sum and phase difference. PACS number: 03.67.-a, 0...

Instantaneous measurements of non-local observables between space-like separated regions can be performed without violating causality. This feat relies on the use of entanglement. Here we propose novel protocols for this task and the related problem of multipartite quantum computation with local operations and a single round of classical communication. Compared to previously known techniques, o...

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...