5,253 research outputs found
Simulation of laser-Compton cooling of electron beams for future linear colliders
We study a method of laser-Compton cooling of electron beams for future
linear colliders. Using a Monte Carlo code, we evaluate the effects of the
laser-electron interaction for transverse cooling. The optics with and without
chromatic correction for the cooling are examined. The laser-Compton cooling
for JLC/NLC at GeV is considered.Comment: 18 pages, 12 figures, 21st ICFA Beam Dynamics Workshop on Laser-Beam
Interactions, Stony Brook, New York, June 11-15, 200
Possible effects of tilt order on phase transitions of a fixed connectivity surface model
We study the phase structure of a phantom tethered surface model shedding
light on the internal degrees of freedom (IDOF), which correspond to the
three-dimensional rod like structure of the lipid molecules. The so-called tilt
order is assumed as IDOF on the surface model. The model is defined by
combining the conventional spherical surface model and the XY model, which
describes not only the interaction between lipids but also the interaction
between the lipids and the surface. The interaction strength between IDOF and
the surface varies depending on the interaction strength between the variables
of IDOF. We know that the model without IDOF undergoes a first-order transition
of surface fluctuations and a first-order collapsing transition. We observe in
this paper that the order of the surface fluctuation transition changes from
first-order to second-order and to higher-order with increasing strength of the
interaction between IDOF variables. On the contrary, the order of collapsing
transition remains first-order and is not influenced by the presence of IDOF.Comment: 20 pages, 14 figure
Bottom-Up Approach to Moduli Dynamics in Heavy Gravitino Scenario : Superpotential, Soft Terms and Sparticle Mass Spectrum
The physics of moduli fields is examined in the scenario where the gravitino
is relatively heavy with mass of order 10 TeV, which is favored in view of the
severe gravitino problem. The form of the moduli superpotential is shown to be
determined, if one imposes a phenomenological requirement that no physical CP
phase arise in gaugino masses from conformal anomaly mediation. This bottom-up
approach allows only two types of superpotential, each of which can have its
origins in a fundamental underlying theory such as superstring. One
superpotential is the sum of an exponential and a constant, which is identical
to that obtained by Kachru et al (KKLT), and the other is the racetrack
superpotential with two exponentials. The general form of soft supersymmetry
breaking masses is derived, and the pattern of the superparticle mass spectrum
in the minimal supersymmetric standard model is discussed with the KKLT-type
superpotential. It is shown that the moduli mediation and the anomaly mediation
make comparable contributions to the soft masses. At the weak scale, the
gaugino masses are rather degenerate compared to the minimal supergravity,
which bring characteristic features on the superparticle masses. In particular,
the lightest neutralino, which often constitutes the lightest superparticle and
thus a dark matter candidate, is a considerable admixture of gauginos and
higgsinos. We also find a small mass hierarchy among the moduli, gravitino, and
superpartners of the standard-model fields. Cosmological implications of the
scenario are briefly described.Comment: 45 pages, 10 figures, typos correcte
Collapsing transition of spherical tethered surfaces with many holes
We investigate a tethered (i.e. fixed connectivity) surface model on
spherical surfaces with many holes by using the canonical Monte Carlo
simulations. Our result in this paper reveals that the model has only a
collapsing transition at finite bending rigidity, where no surface fluctuation
transition can be seen. The first-order collapsing transition separates the
smooth phase from the collapsed phase. Both smooth and collapsed phases are
characterized by Hausdorff dimension H\simeq 2, consequently, the surface
becomes smooth in both phases. The difference between these two phases can be
seen only in the size of surface. This is consistent with the fact that we can
see no surface fluctuation transition at the collapsing transition point. These
two types of transitions are well known to occur at the same transition point
in the conventional surface models defined on the fixed connectivity surfaces
without holes.Comment: 7 pages with 11 figure
Fundamental relation between longitudinal and transverse conductivities in the quantum Hall system
We investigate the relation between the diagonal () and
off-diagonal () components of the conductivity tensor in the
quantum Hall system. We calculate the conductivity components for a short-range
impurity potential using the linear response theory, employing an approximation
that simply replaces the self-energy by a constant value
with the scattering time. The approximation is equivalent to assuming
that the broadening of a Landau level due to disorder is represented by a
Lorentzian with the width . Analytic formulas are
obtained for both and within the framework of this
simple approximation at low temperatures. By examining the leading terms in
and , we find a proportional relation between
and . The relation, after
slight modification to account for the long-range nature of the impurity
potential, is shown to be in quantitative agreement with experimental results
obtained in the GaAs/AlGaAs two-dimensional electron system at the low
magnetic-field regime where spin splitting is negligibly small.Comment: 21 pages, 8 figures, accepted for publication in J. Phys.: Condens.
Matte
Modulation Induced Phase Transition from Fractional Quantum Hall to Stripe State at nu=5/3
We have investigated the effect of unidirectional periodic potential
modulation on the fractional quantum Hall (FQH) state at filling factors nu=5/3
and 4/3. For large enough modulation amplitude, we find that the resistivity
minimum at nu=5/3 gives way to a peak that grows with decreasing temperature.
Density matrix renormalization group calculation reveals that phase transition
from FQH state to unidirectional striped state having a period sim 4 l (with l
the magnetic length) takes place at nu=1/3 (equivalent to nu=5/3 by the
particle-hole symmetry) with the increase of the modulation amplitude,
suggesting that the observed peak is the manifestation of the stripe phase.Comment: 4 pages, 6 figures; minor revisio
Triplet Production by Linearly Polarized Photons
The process of electron-positron pair production by linearly polarized
photons is used as a polarimeter to perform mobile measurement of linear photon
polarization. In the limit of high photon energies, omega, the distributions of
the recoil-electron momentum and azimuthal angle do not depend on the photon
energy in the laboratory frame. We calculate the power corrections of order
m/omega to the above distributions and estimate the deviation from the
asymptotic result for various values of omega.Comment: LaTeX2e, 13 pages, 5 figure files (eps), submitted to Phys. Rev.
Climatic impact of the A.D. 1783 Asama (Japan) Eruption was minimal: Evidence from the GISP2 Ice Core
Assessing the climatic impact of the A.D. 1783 eruption of Mt. Asama, Japan, is complicated by the concurrent eruption of Laki, Iceland. Estimates of the stratospheric loading of H2SO4 for the A.D. 1108 eruption of Asama derived from the SO42− time series in the GISP2 Greenland ice core indicate a loading of about 10.4 Tg H2SO4 with a resulting stratospheric optical depth of 0.087. Assuming sulfur emissions from the 1783 eruption were only one‐third of the 1108 event yields a H2SO4 loading value of 3.5 Tg and a stratospheric optical depth of only 0.029. These results suggest minimal climatic effects in the Northern Hemisphere from the 1783 Asama eruption, thus any volcanically‐induced cooling in the mid‐1780s is probably due to the Laki eruption
Pengaruh Kepuasan Kerja Terhadap Kualitas Layanan Melalui Kinerja Karyawan Fave Hotel Mex Surabaya
Penelitian ini dilakukan untuk mengetahui pengaruh kepuasan kerja terhadap kualitas layanan melalui kinerja karyawan Fave Hotel MEX Surabaya. Jenis penelitian yang digunakan yaitu penelitian kuantitatif hubungan kausalitas dengan teknik partial least square (PLS). Hasil penelitian ini menunjukkan bahwa kepuasan kerja positif dan signifikan mempengaruhi kualitas layanan melalui kinerja karyawan di Fave Hotel MEX Surabaya
- …