32,479 research outputs found
Orthonormalization procedure for chiral effective nuclear field theory
We show that the Q-box expansion of nuclear many-body physics can be applied
in nuclear effective field theory with explicit pions and external sources. We
establish the corresponding power counting and give an algorithm for the
construction of a hermitean and energy-independent potential for arbitrary
scattering processes on nucleons and nuclei to a given order in the chiral
expansion. Various examples are discussed in some detail.Comment: 22 pp, 12 fig
Analysis of Cumulant Moments in High Energy Hadron-Hadron Collisions by Truncated Multiplicity Distributions
Oscillatory behavior of cumulant moments obtained from the experimental data
in collisions and collisions are analyzed by the modified
negative binomial distribution (MNBD) and the negative binomial distribution
(NBD). Both distributions well describe the cumulant moments obtained from the
data. This fact shows sharp contrast to the result in collisions,
which is described by the the MNBD much better than by the NBD.Comment: 7 pages, Latex type, 7 figure
Structure of the baryonic flux tube in N_{f}=2 lattice QCD at finite temperature
We study the flux tube profile in the baryonic system in full QCD at finite
temperature on lattice. We fix the maximally Abelian gauge and
measure the monopole and the photon parts of the Abelian action density, the
color electric field and the monopole current on both sides of the finite
temperature transition. We demonstrate the disappearance of the flux tube in
the high temperature phase.Comment: 3 pages, 4 figures, Lattice2003 topolog
Suppression of compressible edge channels and spatial spin polarization in the integer quantum Hall regime
We perform systematic numerical studies of the structure of spin-resolved
compressible strips in split-gate quantum wires taking into account the
exchange and correlation interactions within the density functional theory in
the local spin-density approximation. We find that for realistic parameters of
the wire the exchange interaction can completely suppress the formation of the
compressible strips. As the depletion length or magnetic field are increased,
the compressible strips starts to form first for the spin-down and then for
spin-up edge channels. We demonstrate that the widths of these strips plus the
spatial separation between them caused by the exchange interaction are equal to
the width of the compressible strip calculated in the Hartree approximation for
spinless electrons. We also discuss the effect of electron density on the
suppression of the compressible strips in quantum wires.Comment: 5 pages, 4 figures, submitted to Phys. Rev.
An effective action for monopoles and knot solitons in Yang-Mills theory
By comparision with numerical results in the maximal Abelian projection of
lattice Yang-Mills theory, it is argued that the nonperturbative dynamics of
Yang Mills theory can be described by a set of fields that take their values in
the coset space SU(2)/U(1). The Yang-Mills connection is parameterized in a
special way to separate the dependence on the coset field. The coset field is
then regarded as a collective variable, and a method to obtain its effective
action is developed. It is argued that the physical excitations of the
effective action may be knot solitons. A procedure to calculate the mass scale
of knot solitons is discussed for lattice gauge theories in the maximal Abelian
projection. The approach is extended to the SU(N) Yang-Mills theory. A relation
between the large N limit and the monopole dominance is pointed out.Comment: plain Latex, 12 pages, no figures, a few references and comments are
added, a final version for Phys. Lett.
More anomaly-free models of six-dimensional gauged supergravity
We construct a huge number of anomaly-free models of six-dimensional N =
(1,0) gauged supergravity. The gauge groups are products of U(1) and SU(2), and
every hyperino is charged under some of the gauge groups. It is also found that
the potential may have flat directions when the R-symmetry is diagonally gauged
together with another gauge group. In an appendix, we determine the
contribution to the global SU(2) anomaly from symplectic Majorana Weyl fermions
in six dimensions.Comment: 20 pages, v3: published versio
The quenching of compressible edge states around antidots
We provide a systematic quantitative description of the edge state structure
around a quantum antidot in the integer quantum Hall regime. The calculations
for spinless electrons within the Hartree approximation reveal that the widely
used Chklovskii et al. electrostatic description greatly overestimates the
widths of the compressible strips; the difference between these approaches
diminishes as the size of the antidot increases. By including spin effects
within density functional theory in the local spin-density approximation, we
demonstrate that the exchange interaction can suppress the formation of
compressible strips and lead to a spatial separation between the spin-up and
spin-down states. As the magnetic field increases, the outermost compressible
strip, related to spin-down states starts to form. However, in striking
contrast to quantum wires, the innermost compressible strip (due to spin-up
states) never develops for antidots.Comment: submitted to Phys. Rev. Let
Vacuum type of SU(2) gluodynamics in maximally Abelian and Landau gauges
The vacuum type of SU(2) gluodynamics is studied using Monte-Carlo
simulations in maximally Abelian (MA) gauge and in Landau (LA) gauge, where the
dual Meissner effect is observed to work. The dual Meissner effect is
characterized by the coherence and the penetration lengths. Correlations
between Wilson loops and electric fields are evaluated in order to measure the
penetration length in both gauges. The coherence length is shown to be fixed in
the MA gauge from measurements of the monopole density around the static
quark-antiquark pair. It is also shown numerically that a dimension 2 gluon
operator A^+A^-(s) and the monopole density has a strong correlation as
suggested theoretically. Such a correlation is observed also between the
monopole density and A^2(s)= A^+A^-(s) + A^3A^3(s) condensate if the remaining
U(1) gauge degree of freedom is fixed to U(1) Landau gauge (U1LA). The
coherence length is determined numerically also from correlations between
Wilson loops and A^+A^-(s) and A^2(s) in MA + U1LA gauge. Assuming that the
same physics works in the LA gauge, we determine the coherence length from
correlations between Wilson loops and A^2(s). Penetration lengths and coherence
lengths in the two gauges are almost the same. The vacuum type of the
confinement phase in both gauges is near to the border between the type 1 and
the type 2 dual superconductors.Comment: 13 pages, 22 figures, RevTeX 4 styl
Exciton Mott transition in Si Revealed by Terahertz Spectroscopy
Exciton Mott transition in Si is investigated by using terahertz time-domain
spectroscopy. The excitonic correlation as manifested by the 1s-2p resonance is
observed above the Mott density. The scattering rate of charge carriers is
prominently enhanced at the proximity of Mott density, which is attributed to
the non-vanishing exciton correlation in the metallic electron-hole plasma.
Concomitantly, the signature of plasmon-exciton coupling is observed in the
loss function spectra.Comment: 5 pages, 3 figure
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