3,453 research outputs found
H-Dihyperon in Quark Cluster Model
The H dihyperon (DH) is studied in the framework of the SU(3) chiral quark
model. It is shown that except the chiral field, the overall effect of
the other SU(3) chiral fields is destructive in forming a stable DH. The
resultant mass of DH in a three coupled channel calculation is ranged from 2225
to 2234 .Comment: 9 pages, emte
Extended states in 1D lattices: application to quasiperiodic copper-mean chain
The question of the conditions under which 1D systems support extended
electronic eigenstates is addressed in a very general context. Using real space
renormalisation group arguments we discuss the precise criteria for determining
the entire spertrum of extended eigenstates and the corresponding
eigenfunctions in disordered as well as quasiperiodic systems. For purposes of
illustration we calculate a few selected eigenvalues and the corresponding
extended eigenfunctions for the quasiperiodic copper-mean chain. So far, for
the infinite copper-mean chain, only a single energy has been numerically shown
to support an extended eigenstate [ You et al. (1991)] : we show analytically
that there is in fact an infinite number of extended eigenstates in this
lattice which form fragmented minibands.Comment: 10 pages + 2 figures available on request; LaTeX version 2.0
Phenomenological study of hadron interaction models
We present a phenomenological study of three models with different effective
degrees of freedom: a Goldstone Boson Exchange (GBE) model which is based on
quark-meson couplings, the quark delocalization, color screening model (QDCSM)
which is based on quark-gluon couplings with delocalized quark wavefunctions,
and the Fujiwara-Nijmegen (FN) mixed model which includes both quark-meson and
quark-gluon couplings. We find that for roughly two-thirds of 64 states
consisting of pairs of octet and decuplet baryons, the three models predict
similar effective baryon-baryon interactions. This suggests that the three very
different models, based on different effective degrees of freedom, are
nonetheless all compatible with respect to baryon spectra and baryon-baryon
interactions. We also discuss the differences between the three models and
their separate characteristics.Comment: 30 pages latex, 7 tables, 12 figs; submitted to Phys. Rev.
Photoresponse of n-ZnO∕p-SiC heterojunction diodes grown by plasma-assisted molecular-beam epitaxy
High quality n-ZnOfilms on commercial p-type 6H–SiC substrates have been grown by plasma-assisted molecular-beam epitaxy, and n-ZnO∕p-SiCheterojunction mesa structures have been fabricated. Current-voltage characteristics of the structures had a very good rectifying diode-like behavior with a leakage current less than 2×10−4A/cm2 at −10V, a breakdown voltage greater than 20V, a forward turn on voltage of ∼5V, and a forward current of ∼2A/cm2 at 8V. Photosensitivity of the diodes was studied at room temperature and a photoresponsivity of as high as 0.045A∕W at −7.5V reverse bias was observed for photonenergies higher than 3.0eV
Statistical correlation for the composite Boson
It is well known that the particles in a beam of Boson obeying Bose-Einstein
statistics tend to cluster (bunching effect), while the particles in a
degenerate beam of Fermion obeying Fermi-Dirac statistics expel each other
(anti-bunching effect). Here we investigate, for the first time, the
statistical correlation effect for the composite Boson, which is formed from a
spin singlet entangled electron pair. By using nonequilibrium Green's function
technique, we obtain a positive cross correlation for this kind of the
composite Boson when the external voltage is smaller than the gap energy, which
demonstrates that a spin singlet entangled electron pair looks like a composite
Boson. In the larger voltage limit, the cross correlation becomes negative due
to the contribution of the quasiparticles. At large voltages, the oscillation
between Fermionic and Bosonic behavior of cross correlation is also observed in
the strong coupling regime as one changes the position of the resonant levels.
Our result can be easily tested in a three-terminal
normal-superconductor-superconductor (N-S-S) hybrid mesoscopic system
Effect of a tilted magnetic field on the orientation of Wigner crystals
We study the effect of a tilted magnetic field on the orientation of Wigner
crystals by taking account of the width of a quantum well in the -direction.
It is found that the cohesive energy of the electronic crystal is always lower
for the direction parallel to the in-plane field. In a realistic
sample, a domain structure forms in the electronic solid and each domain
orients randomly when the magnetic field is normal to the quantum well. As the
field is tilted an angle, the electronic crystal favors to align along a
preferred direction which is determined by the in-plane magnetic field. The
orientation stabilization is strengthened for wider quantum wells as well as
for larger tilted angles. Possible consequence of the tilted field on the
transport property in the electronic solid is discussed
Constraints on the nonuniversal Z^\prime couplings from B\to\pi K, \pi K^{\ast} and \rho K Decays
Motivated by the large difference between the direct CP asymmetries
and , we
combine the up-to-date experimental information on ,
and decays to pursue possible solutions with the nonuniversal
model. Detailed analyses of the relative impacts of different
types of couplings are presented in four specific cases. Numerically, we find
that the new coupling parameters, and with a common
nontrivial new weak phase , which are relevant to the
contributions to the electroweak penguin sector
and , are crucial to the observed " puzzle". Furthermore,
they are found to be definitely unequal and opposite in sign. We also find that
can put a strong constraint on the new
couplings, which implies the contributions to the coefficient of
QCD penguins operator involving the parameter required.Comment: 27 pages, 6 figures. References and a note adde
Modification of the Landau-Lifshitz Equation in the Presence of a Spin-Polarized Current in CMR and GMR Materials
We derive a continuum equation for the magnetization of a conducting
ferromagnet in the presence of a spin-polarized current. Current effects enter
in the form of a topological term in the Landau-Lifshitz equation . In the
stationary situation the problem maps onto the motion of a classical charged
particle in the field of a magnetic monopole. The spatial dependence of the
magnetization is calculated for a one-dimensional geometry and suggestions for
experimental observation are made. We also consider time-dependent solutions
and predict a spin-wave instability for large currents.Comment: 4 two-column pages in RevTex, 3 ps-figure
Large-scale magnetic fields from inflation due to Chern-Simons-like effective interaction
We discuss the generation of large-scale magnetic fields due to the breaking
of the conformal invariance in the electromagnetic field through the -even
dimension-six Chern-Simons-like effective interaction with a fermion current in
inflationary cosmology. It is shown that the magnetic fields on 1Mpc scale with
the field strength of G at the present time can be generated even
for the scale of the effective interaction being the Planck scale.Comment: 13 pages, 2 figures, additional explanations include
p-Adic Mathematical Physics
A brief review of some selected topics in p-adic mathematical physics is
presented.Comment: 36 page
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