45,199 research outputs found
Kinetically-controlled thin-film growth of layered - and NaCoO cobaltate
We report growth characteristics of epitaxial -NaCoO and
-NaCoO thin films on (001) sapphire substrates grown by
pulsed-laser deposition. Reduction of deposition rate could change structure of
NaCoO thin film from -phase with island growth mode to
-phase with layer-by-layer growth mode. The
-NaCoO thin film exhibits spiral surface growth with
multiterraced islands and highly crystallized texture compared to that of the
-NaCoO thin film. This heterogeneous epitaxial film growth
can give opportunity of strain effect of physical properties and growth
dynamics of NaCoO as well as subtle nature of structural change.Comment: accepted for publication in Applied Physics Letter
Meissner effect in the layered Kane-Mele model with Hubbard interaction
We investigate the magnetic response in the quantum spin Hall phase of the
layered Kane-Mele model with Hubbard interaction, and argue a condition to
obtain the Meissner effect. The effect of Rashba spin orbit coupling is also
discussed.Comment: 4 pages, accepted for publication in Journal of Physics: Conference
Series as proceedings of International Symposium "Nanoscience and Quantum
Physics 2011" (nanoPHYS'11) held in Toky
Genuine Non-Self-Averaging and Ultra-Slow Convergence in Gelation
In irreversible aggregation processes droplets or polymers of microscopic
size successively coalesce until a large cluster of macroscopic scale forms.
This gelation transition is widely believed to be self-averaging, meaning that
the order parameter (the relative size of the largest connected cluster)
attains well-defined values upon ensemble averaging with no sample-to-sample
fluctuations in the thermodynamic limit. Here, we report on anomalous gelation
transition types. Depending on the growth rate of the largest clusters, the
gelation transition can show very diverse patterns as a function of the control
parameter, which includes multiple stochastic discontinuous transitions,
genuine non-self-averaging and ultra-slow convergence of the transition point.
Our framework may be helpful in understanding and controlling gelation.Comment: 8 pages, 10 figure
Strong and Electromagnetic Decays of Two New Baryons
Two recently discovered excited charm baryons are studied within the
framework of Heavy Hadron Chiral Perturbation Theory. We interpret these new
baryons which lie 308 \MeV and 340 \MeV above the as
members of a P-wave spin doublet. Differential and total decay rates for their
double pion transitions down to the ground state are calculated.
Estimates for their radiative decay rates are also discussed. We find that the
experimentally determined characteristics of the baryons may be
simply understood in the effective theory.Comment: 16 pages with 4 figures not included but available upon request,
CALT-68-191
Comment on Decay
We calculate the rate for decay using Chiral
Perturbation Theory. This isospin violating process results from -
mixing, and its amplitude is proportional to . Experimental information on the branching
ratio for can provide insight into the pattern of
violation in radiative decays.Comment: 7 pages with 2 figures not included but available upon request,
CALT-68-191
QCD effective action with a most general homogeneous field background
We consider one-loop effective action of SU(3) QCD with a most general
constant chromomagnetic (chromoelectric) background which has two independent
Abelian field components. The effective potential with a pure magnetic
background has a local minimum only when two Abelian components H_{\mu\nu}^3
and H_{\mu\nu}^8 of color magnetic field are orthogonal to each other. The
non-trivial structure of the effective action has important implication in
estimating quark-gluon production rate and p_T-distribution in quark-gluon
plasma. In general the production rate depends on three independent Casimir
invariants, in particular, it depends on the relative orientation between
chromoelectric fields.Comment: 6 pages, 3 figures (9 pages in published version
Simultaneously imaging of dielectric properties and topography in a PbTiO_3 crystal by near-field scanning microwave microscopy
We use a near-field scanning microwave microscope to simultaneously image the
dielectric constant, loss tangent, and topography in a PbTiO_3 crystal. By this
method, we study the effects of the local dielectric constant and loss tangent
in the geometry of periodic domains on the measured resonant frequency, and
quality factor. We also carry out theoretical calculations and the results
agree well with the experimental data and reveal the anisotropic nature of
dielectric constant
Compressible Sub-Alfvenic MHD turbulence in Low-beta Plasmas
We present a model for compressible sub-Alfvenic isothermal
magnetohydrodynamic (MHD) turbulence in low-beta plasmas and numerically test
it. We separate MHD fluctuations into 3 distinct families - Alfven, slow, and
fast modes. We find that, production of slow and fast modes by Alfvenic
turbulence is suppressed. As a result, Alfven modes in compressible regime
exhibit scalings and anisotropy similar to those in incompressible regime. Slow
modes passively mimic Alfven modes. However, fast modes show isotropy and a
scaling similar to acoustic turbulence.Comment: 4 pages, 8 figures, Phys. Rev. Lett., in pres
Magnetic Moments of Heavy Baryons
First non-trivial chiral corrections to the magnetic moments of triplet (T)
and sextet (S^(*)) heavy baryons are calculated using Heavy Hadron Chiral
Perturbation Theory. Since magnetic moments of the T-hadrons vanish in the
limit of infinite heavy quark mass (m_Q->infinity), these corrections occur at
order O(1/(m_Q \Lambda_\chi^2)) for T-baryons while for S^(*)-baryons they are
of order O(1/\Lambda_\chi^2). The renormalization of the chiral loops is
discussed and relations among the magnetic moments of different hadrons are
provided. Previous results for T-baryons are revised.Comment: 11 Latex pages, 2 figures, to be published in Phys.Rev.
Weak boson fusion production of supersymmetric particles at the LHC
We present a complete calculation of weak boson fusion production of
colorless supersymmetric particles at the LHC, using the new matrix element
generator SUSY-MadGraph. The cross sections are small, generally at the
attobarn level, with a few notable exceptions which might provide additional
supersymmetric parameter measurements. We discuss in detail how to consistently
define supersymmetric weak couplings to preserve unitarity of weak gauge boson
scattering amplitudes to fermions, and derive sum rules for weak supersymmetric
couplings.Comment: 24 p., 3 fig., 9 tab., published in PRD; numbers in Table IV
corrected to those with kinematic cuts cite
- …