14,272 research outputs found
Case of Almost Redundant Components in 3 alpha Faddeev Equations
The 3 alpha orthogonality condition model using the Pauli-forbidden bound
states of the Buck, Friedlich and Wheatly alpha alpha potential can yield a
compact 3 alpha ground state with a large binding energy, in which a small
admixture of the redundant components can never be eliminated.Comment: Revtex V4.0, 4 pages, no figure
Spectrum of the Hermitian Wilson-Dirac Operator for a Uniform Magnetic Field in Two Dimensions
It is shown that the eigenvalue problem for the hermitian Wilson-Dirac
operator of for a uniform magnetic field in two dimensions can be reduced to
one-dimensional problem described by a relativistic analog of the Harper
equation. An explicit formula for the secular equations is given in term of a
set of polynomials. The spectrum exhibits a fractal structure in the infinite
volume limit. An exact result concerning the index theorem for the overlap
Dirac operator is obtained.Comment: 8 pages, latex, 3 eps figures, minor correction
Single-Particle Spin-Orbit Strengths of the Nucleon and Hyperons by SU6 Quark-Model
The quark-model hyperon-nucleon interaction suggests an important
antisymmetric spin-orbit component. It is generated from a color analogue of
the Fermi-Breit interaction dominating in the one-gluon exchange process
between quarks. We discuss the strength S_B of the single-particle spin-orbit
potential, following the Scheerbaum's prescription. Using the SU6 quark-model
baryon-baryon interaction which was recently developed by the Kyoto-Niigata
group, we calculate NN, Lambda N and Sigma N G-matrices in symmetric nuclear
matter and apply them to estimate the strength S_B. The ratio of S_B to the
nucleon strength S_N =~ -40 MeV*fm^5 is (S_Lambda)/(S_N) =~ 1/5 and
(S_Sigma)/(S_N) =~ 1/2 in the Born approximation. The G-matrix calculation of
the model FSS modifies S_Lambda to (S_Lambda)/(S_N) =~ 1/12. For S_N and
S_Sigma, the effect of the short-range correlation is comparatively weak
against meson-exchange potentials with a short-range repulsive core. The
significant reduction of the Lambda single-particle potential arises from the
combined effect of the antisymmetric LS force, the flavor-symmetry breaking
originating from the strange to up-down quark-mass difference, as well as the
effect of the short-range correlation. The density dependence of S_B is also
examined.Comment: 26 page
Interactions between Octet Baryons in the SU_6 Quark model
The baryon-baryon interactions for the complete baryon octet (B_8) are
investigated in a unified framework of the resonating-group method, in which
the spin-flavor SU_6 quark-model wave functions are employed. Model parameters
are determined to reproduce properties of the nucleon-nucleon system and the
low-energy cross section data for the hyperon-nucleon interaction. We then
proceed to explore B_8 B_8 interactions in the strangeness S=-2, -3 and -4
sectors. The S-wave phase-shift behavior and total cross sections are
systematically understood by 1) the spin-flavor SU_6 symmetry, 2) the special
role of the pion exchange, and 3) the flavor symmetry breaking.Comment: 11 pages, 6 figures, submitted to Phys. Rev. C (Rapid Communication
Hyperon Single-Particle Potentials Calculated from SU6 Quark-Model Baryon-Baryon Interactions
Using the SU6 quark-model baryon-baryon interaction recently developed by the
Kyoto-Niigata group, we calculate NN, Lambda N and Sigma N G-matrices in
ordinary nuclear matter. This is the first attempt to discuss the Lambda and
Sigma single-particle potentials in nuclear medium, based on the realistic
quark-model potential. The Lambda potential has the depth of more than 40 MeV,
which is more attractive than the value expected from the experimental data of
Lambda-hypernuclei. The Sigma potential turns out to be repulsive, the origin
of which is traced back to the strong Pauli repulsion in the Sigma N (I=3/2)
^3S_1 state.Comment: 20 pages, 5 figure
Simulating Capacitances to Silicon Quantum Dots: Breakdown of the Parallel Plate Capacitor Model
Many electrical applications of quantum dots rely on capacitively coupled
gates; therefore, to make reliable devices we need those gate capacitances to
be predictable and reproducible. We demonstrate in silicon nanowire quantum
dots that gate capacitances are reproducible to within 10% for nominally
identical devices. We demonstrate the experimentally that gate capacitances
scale with device dimensions. We also demonstrate that a capacitance simulator
can be used to predict measured gate capacitances to within 20%. A simple
parallel plate capacitor model can be used to predict how the capacitances
change with device dimensions; however, the parallel plate capacitor model
fails for the smallest devices because the capacitances are dominated by
fringing fields. We show how the capacitances due to fringing fields can be
quickly estimated.Comment: 4 pages, 3 figures, to be published in IEEE Trans. Nan
Triton binding energy calculated from the SU_6 quark-model nucleon-nucleon interaction
Properties of the three-nucleon bound state are examined in the Faddeev
formalism, in which the quark-model nucleon-nucleon interaction is explicitly
incorporated to calculate the off-shell T-matrix. The most recent version,
fss2, of the Kyoto-Niigata quark-model potential yields the ground-state energy
^3H=-8.514 MeV in the 34 channel calculation, when the np interaction is used
for the nucleon-nucleon interaction. The charge root mean square radii of the
^3H and ^3He are 1.72 fm and 1.90 fm, respectively, including the finite size
correction of the nucleons. These values are the closest to the experiments
among many results obtained by detailed Faddeev calculations employing modern
realistic nucleon-nucleon interaction models.Comment: 10 pages, no figure
Comparison between the Cramer-Rao and the mini-max approaches in quantum channel estimation
In a unified viewpoint in quantum channel estimation, we compare the
Cramer-Rao and the mini-max approaches, which gives the Bayesian bound in the
group covariant model. For this purpose, we introduce the local asymptotic
mini-max bound, whose maximum is shown to be equal to the asymptotic limit of
the mini-max bound. It is shown that the local asymptotic mini-max bound is
strictly larger than the Cramer-Rao bound in the phase estimation case while
the both bounds coincide when the minimum mean square error decreases with the
order O(1/n). We also derive a sufficient condition for that the minimum mean
square error decreases with the order O(1/n).Comment: In this revision, some unlcear parts are clarifie
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