3,369 research outputs found
Entanglement of Indistinguishable Particles
We present a general criterion for entanglement of N indistinguishable
particles decomposed into arbitrary s subsystems based on the unambiguous
measurability of correlation. Our argument provides a unified viewpoint on the
entanglement of indistinguishable particles, which is still unsettled despite
various proposals made mainly for the s = 2 case. Even though entanglement is
defined only with reference to the measurement setup, we find that the
so-called i.i.d. states form a special class of bosonic states which are
universally separable.Comment: 6 pages, 3 figures, major revisio
Chiral Corrections to the Hyperon Vector Form Factors
We present the complete calculation of the SU(3)-breaking corrections to the
hyperon vector form factors up to O(p^4) in the Heavy Baryon Chiral
Perturbation Theory. Because of the Ademollo-Gatto theorem, at this order the
results do not depend on unknown low energy constants and allow to test the
convergence of the chiral expansion. We complete and correct previous
calculations and find that O(p^3) and O(1/M_0) corrections are important. We
also study the inclusion of the decuplet degrees of freedom, showing that in
this case the perturbative expansion is jeopardized. These results raise doubts
on the reliability of the chiral expansion for hyperons.Comment: 20 pages, 4 figures, v2: published versio
Impedance Evaluation of the SPS MKE Kicker with Transition Pieces between Tank and Kicker Module
In this paper we discuss longitudinal beam coupling impedance measurements performed with the coaxial wire method on a modified prototype of the SPS MKE kicker. The frequency dependent real and imaginary part of the distributed coupling impedance are obtained from the measured S-parameters by standard and improved log-formulae. A comparison with theoretical models and previous measurements is discussed as well
Spin-torque efficiency enhanced by Rashba spin splitting in three dimensions
We examine a spin torque induced by the Rashba spin-orbit coupling in three
dimensions within the Boltzmann transport theory. We analytically calculate the
spin torque and show how its behavior is related with the spin topology in the
Fermi surfaces by studying the Fermi-energy dependence of the spin torque.
Moreover we discuss the spin-torque efficiency which is the spin torque divided
by the applied electric current in association with the current-induced
magnetization reversal. It is found that high spin-torque efficiency is
achieved when the Fermi energy lies on only the lower band and there exists an
optimal value for the Rashba parameter, where the spin-torque efficiency
becomes maximum.Comment: 7 pages, 5 figure
Electron-phonon coupling and spin-charge separation in one-dimensional Mott insulators
We examine the single-particle excitation spectrum in the one-dimensional
Hubbard-Holstein model at half-filling by performing the dynamical density
matrix renormalization group (DDMRG) calculation. The DDMRG results are
interpreted as superposition of spectra for a spinless carrier dressed with
phonons. The superposition is a consequence of robustness of the spin-charge
separation against electron-phonon coupling. The separation is in contrast to
the coupling between phonon and spin degrees of freedom in two-dimensional
systems. We discuss implication of the results of the recent angle-resolved
photoemission spectroscopy measurements on SrCuO.Comment: 5 pages, 4 figures. submitted to the Physical Review Letter
Softening of Cu-O bond stretching phonon in tetragonal HgBaCuO
Phonons in nearly optimally doped HgBaCuO were studied by
inelastic X-ray scattering. The dispersion of the low energy modes is well
described by a shell model, while the Cu-O bond stretching mode at high energy
shows strong softening towards the zone boundary, which deviates strongly from
the model. This seems to be common in the hole-doped high-
superconducting cuprates, and, based on this work, not related to a lattice
distortion specific to each material.Comment: 5 pages, 4 figures, accepted for publication in Phys. Rev. Let
Nucleon decay matrix elements with the Wilson quark action: an update
We present preliminary results of a new lattice computation of hadronic
matrix elements of baryon number violating operators which appear in the
low-energy effective Lagrangian of (SUSY-)Grand Unified Theories. The
contribution of irrelevant form factor which has caused an underestimate of the
matrix elements in previous studies is subtracted in this calculation. Our
results are 24 times larger than the most conservative values often
employed in phenomenological analyses of nucleon decay with specific GUT
models.Comment: LATTICE99(matrixelements), 3 pages, 2 figure
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