6,081 research outputs found
Flavor independent systematics of excited baryons and intra-band transition
Transitions among excited nucleons are studied within a non-relativistic
quark model with a deformed harmonic oscillator potential. The transition
amplitudes are factorized into the -th moment and a geometrical factor. This
fact leads to an analogous result to the ``Alaga-rule'' for baryons.Comment: 4 Pages, 2 figures, Talk given at XVI International Conference on
Particles and Nuclei (PaNic02), Osaka, Japan, Sep.30 - Oct.4, 200
Comment on "Memory Effects in an Interacting Magnetic Nanoparticle System"
In Phys. Rev. Lett. 91 167206 (2003), Sun et al. study memory effects in an
interacting nanoparticle system with specific temperature and field protocols.
The authors claim that the observed memory effects originate from spin-glass
dynamics and that the results are consistent with the hierarchical picture of
the spin-glass phase. In this comment, we argue their claims premature by
demonstrating that all their experimental curves can be reproduced
qualitatively using only a simplified model of isolated nanoparticles with a
temperature dependent distribution of relaxation times.Comment: 1 page, 2 figures, slightly changed content, the parameters involved
in Figs. 1 and 2 are changed a little for a semi-quantitative comparision
with experimental result
Hybrid Simulation between Molecular Dynamics and Binary Collision Approximation Codes for Hydrogen injection onto Carbon Materials
Molecular dynamics (MD) simulation with modified Brenner's reactive empirical
bond order (REBO) potential is a powerful tool to investigate plasma wall
interaction on divertor plates in a nuclear fusion device. However, MD
simulation box's size is less than several nm for the performance of a
computer. To extend the size of the MD simulation, we develop a hybrid
simulation code between MD code using REBO potential and binary collision
approximation (BCA) code. Using the BCA code instead of computing all particles
with a high kinetic energy for every step in the MD simulation, considerable
computation time is saved. By demonstrating a hydrogen atom injection on a
graphite by the hybrid simulation code, it is found that the hybrid simulation
code works efficiently in a large simulation box.Comment: 5 pages, 5 figure
Diffusion of single long polymers in fixed and low density matrix of obstacles confined to two dimensions
Diffusion properties of a self-avoiding polymer embedded in regularly
distributed obstacles with spacing a=20 and confined in two dimensions is
studied numerically using the extended bond fluctuation method which we have
developed recently. We have observed for the first time to our knowledge, that
the mean square displacement of a center monomer exhibits four
dynamical regimes, i.e., with ,
3/8, 3/4, and 1 from the shortest to longest time regimes. The exponents in the
second and third regimes are well described by segmental diffusion in the
``self-avoiding tube''. In the fourth (free diffusion) regime, we have
numerically confirmed the relation between the reptation time and the
number of segments .Comment: 7 pages, 11 figure
Temperature Chaos and Bond Chaos in the Edwards-Anderson Ising Spin Glass : Domain-Wall Free-Energy Measurements
Domain-wall free-energy , entropy , and the correlation
function, , of are measured independently in the
four-dimensional Edwards-Anderson (EA) Ising spin glass. The stiffness
exponent , the fractal dimension of domain walls and the
chaos exponent are extracted from the finite-size scaling analysis of
, and respectively well inside the
spin-glass phase. The three exponents are confirmed to satisfy the scaling
relation derived by the droplet theory within our
numerical accuracy. We also study bond chaos induced by random variation of
bonds, and find that the bond and temperature perturbations yield the universal
chaos effects described by a common scaling function and the chaos exponent.
These results strongly support the appropriateness of the droplet theory for
the description of chaos effect in the EA Ising spin glasses.Comment: 4 pages, 6 figures; The title, the abstract and the text are changed
slightl
Scaling Analysis of Domain-Wall Free-Energy in the Edwards-Anderson Ising Spin Glass in a Magnetic Field
The stability of the spin-glass phase against a magnetic field is studied in
the three and four dimensional Edwards-Anderson Ising spin glasses. Effective
couplings and effective fields associated with length scale L are measured by a
numerical domain-wall renormalization group method. The results obtained by
scaling analysis of the data strongly indicate the existence of a crossover
length beyond which the spin-glass order is destroyed by field H. The crossover
length well obeys a power law of H which diverges as H goes to zero but remains
finite for any non-zero H, implying that the spin-glass phase is absent even in
an infinitesimal field. These results are well consistent with the droplet
theory for short-range spin glasses.Comment: 4 pages, 5 figures; The text is slightly changed, the figures 3, 4
and 5 are changed, and a few references are adde
Electronic properties of the novel 4d metallic oxide SrRhO3
The novel 4d perovskite compound SrRhO3 was investigated by isovalent doping
studies. The solubility limits of Ca and Ba onto Sr-site were below 80% and
20%, respectively. Although SrRhO3 was chemically compressed, approximately
5.7% by the Ca doping, no significant influence was observed on the magnetic
and electrical properties.Comment: To be published in a special issue of Physica B (the proceedings of
LT23
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