57,398 research outputs found
Non-Markovian disentanglement dynamics of two-qubit system
We investigated the disentanglement dynamics of two-qubit system in
Non-Markovian approach. We showed that only the couple strength with the
environment near to or less than fine-structure constant 1/137, entanglement
appear exponential decay for a certain class of two-qubit entangled state.
While the coupling between qubit and the environment is much larger, system
always appears the sudden-death of entanglement even in the vacuum environment.Comment: 17 pages, 3 figure
The many facets of the (non relativistic) Nuclear Equation of State
A nucleus is a quantum many body system made of strongly interacting
Fermions, protons and neutrons (nucleons). This produces a rich Nuclear
Equation of State whose knowledge is crucial to our understanding of the
composition and evolution of celestial objects. The nuclear equation of state
displays many different features; first neutrons and protons might be treated
as identical particles or nucleons, but when the differences between protons
and neutrons are spelled out, we can have completely different scenarios, just
by changing slightly their interactions. At zero temperature and for neutron
rich matter, a quantum liquid gas phase transition at low densities or a
quark-gluon plasma at high densities might occur. Furthermore, the large
binding energy of the particle, a Boson, might also open the
possibility of studying a system made of a mixture of Bosons and Fermions,
which adds to the open problems of the nuclear equation of state.Comment: 71 pages, 30 figures, accepted by Prog. Part. Nucl. Phys. and in
pres
Multiple Superconducting Gaps, Anisotropic Spin Fluctuations and Spin-Orbit Coupling in Iron-Pnictides
This article reviews the NMR and NQR studies on iron-based high-temperature
superconductors by the IOP/Okayama group. It was found that the electron pairs
in the superconducting state are in the spin-singlet state with multiple
fully-opened energy gaps. The antiferromagnetic spin fluctuations in the normal
state are found to be closely correlated with the superconductivity. Also the
antiferromagnetic spin fluctuations are anisotropic in the spin space, which is
different from the case in copper oxide superconductors. This anisotropy
originates from the spin-orbit coupling and is an important reflection of the
multiple-bands nature of this new class of superconductors.Comment: 20 pages, 16 figure
Transition behavior of k-surface from hyperbola to ellipse
The transition behavior of the k-surface of a lossy anisotropic indefinite slab is investigated. It is found that, if the material loss is taken into account, the k-surface does not show a sudden change from hyperbola to the ellipse when one principle element of the permittivity tensor changes from negative to positive. In fact, after introducing a small material loss, the shape of the k-surface can be a combination of a hyperbola and an ellipse, and a selective high directional transmission can be obtained in such a slab
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