57,315 research outputs found
Orbital Magnetism and Transport Phenomena in Two Dimensional Dirac Fermions in Weak Magnetic Field
We discuss the orbital magnetism and the Hall effect in the weak magnetic
field in two dimensional Dirac fermion systems with energy gap. This model is
related to the graphene sheet, organic conductors, and -density wave
superconductors. We found the strong diamagnetism and finite Hall conductivity
even in gapped systems. We also discuss the relation between the weak-magnetic
field formalism and the Landau quantization with the Euler-Maclaurin expansion.Comment: 4pages,3figure
QCD color interactions between two quarks
We study the QCD color interactions between static two heavy quarks at zero
temperature in a quenched SU(3) lattice gauge simulation: in addition to the
standard singlet potentials, we calculate octet
potentials, symmetric and antisymmetric potentials. It is shown that the
antisymmetric channel behaves as a linearly rising potential at large
quark separations. We further find that the octet and symmetric
channels have the complex dependence on the distance; at short distances they
are repulsive forces, while at large distances, they show linearly rising
feature. Ratio of string tensions between singlet and
antisymmetric potentials is described in terms of the Casimir factor
Monte Carlo Study of Two-Color QCD with Finite Chemical Potential - Status report of Wilson fermion simulation
Using Wilson fermions, we study SU(2) lattice QCD with the chemical potential
at . The ratio of fermion determinants is evaluated at each
Metropolis link update step. We calculate the baryon number density, the
Polyakov loops and the pseudoscalar and vector masses on and lattices. Preliminary data show the pseudoscalar meson becomes massive
around , which indicates the chiral symmetry restoration. The
calculation is broken down when approaching to the transition region. We
analyze the behavior of the fermion determinant and eigen value distributions
of the determinant, which shows a peculiar ``Shell-and-Bean'' pattern near the
transition.Comment: 4 pages, 5 figures, Lattice 2000 (Finite Density
Molecular Dynamics Simulation of Collisions between Hydrogen and Graphite
Hydrogen adsorption by graphite is examined by classical molecular dynamics
simulation using a modified Brenner REBO potential. Such interactions are
typical in chemical sputtering experiments, and knowledge of the fundamental
behavior of hydrogen and graphene in collisional conditions is essential for
modeling the sputtering mechanism. The hydrogen adsorption rate is found to be
dependent on the incident hydrogen energy and not on graphene temperature.
Rather than destroying the graphene, hydrogen incidence at energies of less
than 100 eV can be classified into three regimes of adsorption, reflection and
penetration through one or more graphene layers. Incidence at the lowest
energies is shown to distort the graphene structure.Comment: 4 pages, 4 figures. Accepted for publication by j. Plasma Phys.
Proccedings for the joint conference of 19th International Conference on
Numerical Simulation of Plasmas and 7th Asia Pacific Plasma Theor
Transport Coefficients of Quark Gluon Plasma From Lattice Gauge Theory
Numerical results for the transport coefficients of quark gluon plasma are
obtained by lattice simulations on on lattice with the quench
approximation where we apply the gauge action proposed by Iwasaki. The bulk
viscosity is consistent with zero, and the shear viscosity is slightly smaller
than the typical hadron masses. They are not far from the simple extrapolation
on the figure of perturbative calculation in high temperature limit down to . The gluon propagator in the confined and deconfined phases are
also discussed.Comment: Quark Matter 97(talk at parallel session QCD) 4 pages in latex, 4
Postscript figure
Toda Lattice and Tomimatsu-Sato Solutions
We discuss an analytic proof of a conjecture (Nakamura) that solutions of
Toda molecule equation give those of Ernst equation giving Tomimatsu-Sato
solutions of Einstein equation. Using Pfaffian identities it is shown for Weyl
solutions completely and for generic cases partially.Comment: LaTeX 8 page
Gluon Propagators and Confinement
We present SU(3) gluon propagators calculated on 48*48*48*N_t lattices at
beta=6.8 where N_t=64 (corresponding the confinement phase) and N_t=16
(deconfinement) with the bare gauge parameter,alpha, set to be 0.1. In order to
avoid Gribov copies, we employ the stochastic gauge fixing algorithm. Gluon
propagators show quite different behavior from those of massless gauge fields:
(1) In the confinement phase, G(t) shows massless behavior at small and large
t, while around 5<t<15 it behaves as massive particle, and (2) effective mass
observed in G(z) becomes larger as z increases. (3) In the deconfinement phase,
G(z) shows also massive behavior but effective mass is less than in the
confinement case. In all cases, slope masses are increasing functions of t or
z, which can not be understood as addtional physical poles.Comment: 6 pages in Postscrip
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