title: Kerr-Schild Riemannian acoustic black holes in dynamo plasma laboratory

abstract:
  Since Alfven, dynamo and sound waves and the existence of general
relativistic black holes are well stablished in plasma physics, this provides
enough motivation to investigate the presence of acoustic black-hole effective
metric of analogue Einstein's gravity in dynamo flows. From nonlinear dynamo
equations, one obtains a non-homogeneous wave equation where it is shown that
the non-homogeneous factor is proportional to time evolution of the
compressibility factor. In the Navier-Stokes case for a finite Reynolds number
the acoustic black-holes also exists on the stretching plasma flows. In the
magnetostatic case the dynamo is marginal. Analog models are usually applied to
a superfluid analog spacetime, instead of the plasma setting used here. A
coupled nonlinear plasma flow solution is found for the dynamo equation where
the effective black hole solution of the scalar effective equation yields an
imaginary part of the growth of magnetic field. Therefore though the real part
of the growth rate of the magnetic field is negative or null, since there is a
temporal oscillation in magnetic field, the solution represents a slow dynamo.
Thus acoustic black holes are shown to definitely contribute to dynamo action
of the effective plasma spacetime. It is suggested that a fast dynamo effective
spacetime may also contain an acoustic black hole. I the case of planar waves
the effective metric can be cast in Kerr-Schild spacetime form. The Killing
symmetries are explicitly given in this metric and the growth of dynamo waves.


title: Effective black holes from non-Riemannian vortex acoustics in ABC flows


title: A Possible Icy Kuiper Belt around HD 181327

abstract:
  We have obtained a Gemini South T-ReCS Qa-band (18.3 micron) image and a
Spitzer MIPS SED-mode observation of HD181327, an F5/F6V member of the ~12 Myr
old beta Pictoris moving group. We resolve the disk in thermal-emission for the
first time and find that the northern arm of the disk is 1.4x brighter than the
southern arm. In addition, we detect a broad peak in the combined Spitzer IRS
and MIPS spectra at 60 - 75 micron that may be produced by emission from
crystalline water ice. We model the IRS and MIPS data using a size distribution
of amorphous olivine and water ice grains (dn/da proportional to a^{-2.25} with
a_{min} consistent with the minimum blow out size and a_{max} = 20 micron)
located at a distance of 86.3 AU from the central star, as observed in
previously published scattered-light images. Since the photo-desorption
lifetime for the icy particles is ~1400 yr, significantly less than the
estimated ~12 Myr age of the system, we hypothesize that we have detected
debris that may be steadily replenished by collisions among icy Kuiper belt
object-like parent bodies in a newly forming planetary system.


title: Finsler geometry and actions of the p-Schatten unitary groups

abstract:
  Let $p$ be an even positive integer and $U_p(H)$ be the Banach-Lie group of
unitary operators $u$ which verify that $u-1$ belongs to the $p$-Schatten ideal
$B_p(H)$. Let ${\cal O}$ be a smooth manifold on which $U_p(H)$ acts
transitively and smoothly. Then one can endow ${\cal O}$ with a natural Finsler
metric in terms of the $p$-Schatten norm and the action of $U_p(H)$. Our main
result establishes that for any pair of given initial conditions $$ x\in {\cal
O}\hbox{and} X\in (T{\cal O})_x $$ there exists a curve $\delta(t)=e^{tz}\cdot
x$ in ${\cal O}$, with $z$ a skew-hermitian element in the $p$-Schatten class
such that $$ \delta(0)=x \hbox{and} \dot{\delta}(0)=X, $$ which remains minimal
as long as $t\|z\|_p\le \pi/4$. Moreover, $\delta$ is unique with these
properties. We also show that the metric space $({\cal O},d)$ ($d=$ rectifiable
distance) is complete. In the process we establish minimality results in the
groups $U_p(H)$, and a convexity property for the rectifiable distance. As an
example of these spaces, we treat the case of the unitary orbit $$ {\cal
O}=\{uAu^*: u\in U_p(H)\} $$ of a self-adjoint operator $A\in B(H)$.


title: Norm Inequalities in Operator Ideals

abstract:
  In this paper we introduce a new technique for proving norm inequalities in
operator ideals with an unitarily invariant norm. Among the well known
inequalities which can be proved with this technique are the L\"owner-Heinz
inequality, inequalities relating various operator means and the
Corach-Porta-Recht inequality. We prove two general inequalities and from them
we derive several inequalities by specialization, many of them new. We also
show how some inequalities, known to be valid for matrices or bounded
operators, can be extended with this technique to normed ideals in
$C^*$-algebras, in particular to the noncommutative $L^p$-spaces of a
semi-finite von Neumann algebra.


title:
Some Composite Hadrons and Leptons which induce Supersymmetry Breaking
  in the Supersymmetric Standard Model: Cybersusy III

abstract:
  This is the third paper in a series of four papers which introduce cybersusy,
which is a new mechanism for supersymmetry breaking in the supersymmetric
standard model (SSM). In this paper we display some solutions to the constraint
equations of BRS cohomology in the SSM. In particular we discuss the leptonic
dotspinor pseudosupermultiplets that were used in Cybersusy I to calculate
leptonic supersymmetry breaking in the supersymmetric standard model. We also
introduce examples of hadronic dotspinor pseudosupermultiplets that will induce
baryonic supersymmetry breaking in the SSM for the baryons with charge Q=-1,
and related supersymmetry partner baryons. Some interesting relationships
between the peculiar structure of the SSM, the existence of solutions for the
BRS constraints, and supersymmetry breaking using cybersusy are noted.


title:
Quasi-Hilda Comet 147P/Kushida-Muramatsu: Another long temporary
  satellite capture by Jupiter

abstract:
  The quasi-Hilda comets (QHCs), being in unstable 3:2 Jovian mean motion
resonance, are considered a major cause of temporary satellite capture (TSC) by
Jupiter. Though the QHCs may be escaped Hilda asteroids, their origin and
nature have not yet been studied in sufficient detail. Of particular interest
are long TSCs/orbiters. Orbiters -- in which at least one full revolution about
the planet is completed -- are rare astronomical events; only four have been
known to occur in the last several decades. Every case has been associated with
a QHC: 82P/Gehrels 3; 111P/Helin-Roman-Crockett; P/1996 R2 (Lagerkvist); and
the possibly QHC-derived D/1993 F2 (Shoemaker-Levy 9, SL9). We focus on long
TSC/orbiter events involving QHCs and Jupiter. Thus we survey the known QHCs,
searching for further long TSCs/orbiters over the past century. First, we
confirmed the long TSC/orbiter events of 82P, 111P, and 1996 R2 in order to
test our method against previous work, applying a general N-body Newtonian
code. We then used the same procedure to survey the remaining known QHCs and
search for long TSC/orbiter events. We newly identified another long
TSC/orbiter: 147P/Kushida-Muramatsu from 1949 May 14 (+97days/-106 days)--1961
July 15. Our result is verified by integrations of 243 cloned orbits which take
account of the present orbital uncertainty of this comet. This is the third
long TSC and the fifth orbiter to be found, thus long TSC/orbiter events
involving Jupiter have occurred once per decade. Two full revolutions about
Jupiter were completed and the capture duration was 12.17 (+0.29/-0.27) years;
both these numbers rank 147P as third among long TSC/orbiter events, behind SL9
and 111P. This study also confirms the importance of the QHC region as a
dynamical route into and out of Jovian TSC, via the Hill's sphere.


title:
Electrostatic fluctuations in cavities within polar liquids and
  thermodynamics of polar solvation

abstract:
  We present the results of numerical simulations of fluctuations of the
electrostatic potential and electric field inside cavities created in the fluid
of dipolar hard spheres. We found that the thermodynamics of polar solvation
dramatically changes its regime when the cavity size becomes about 4-5 times
larger than the size of the liquid particle. The range of small cavities can be
reasonably understood within the framework of current solvation models. On the
contrary, the regime of large cavities is characterized by a significant
softening of the cavity interface resulting in a decay of the fluctuation
variances with the cavity size much faster than anticipated by both the
continuum electrostatics and microscopic theories. For instance, the variance
of potential decays with the cavity size $R_0$ approximately as $1/R_0^{4-6}$
instead of the $1/R_0$ scaling expected from standard electrostatics. Our
results suggest that cores of non-polar molecular assemblies in polar liquids
lose solvation strength much faster than is traditionally anticipated.


title: On conformal biharmonic immersions

abstract:
  This paper studies conformal biharmonic immersions. We first study the
transformations of Jacobi operator and the bitension field under conformal
change of metrics. We then obtain an invariant equation for a conformal
biharmonic immersion of a surface into Euclidean 3-space. As applications, we
construct a 2-parameter family of non-minimal conformal biharmonic immersions
of cylinder into $\r^3$ and some examples of conformal biharmonic immersions of
4-dimensional Euclidean space into sphere and hyperbolic space thus provide
many simple examples of proper biharmonic maps with rich geometric meanings.
These suggest that there are abundant proper biharmonic maps in the family of
conformal immersions. We also explore the relationship between biharmonicity
and holomorphicity of conformal immersions of surfaces.


title: Spatial Interference: From Coherent To Incoherent

abstract:
  It is well known that direct observation of interference and diffraction
pattern in the intensity distribution requires a spatially coherent source.
Optical waves emitted from portions beyond the coherence area possess
statistically independent phases, and will degrade the interference pattern. In
this paper we show an optical interference experiment, which seems contrary to
our common knowledge, that the formation of the interference pattern is related
to a spatially incoherent light source. Our experimental scheme is very similar
to Gabor's original proposal of holography[1], just with an incoherent source
replacing the coherent one. In the statistical ensemble of the incoherent
source, each sample field produces a sample interference pattern between object
wave and reference wave. These patterns completely differ from each other due
to the fluctuation of the source field distribution. Surprisingly, the sum of a
great number of sample patterns exhibits explicitly an interference pattern,
which contains all the information of the object and is equivalent to a
hologram in the coherent light case. In this sense our approach would be
valuable in holography and other interference techniques for the case where
coherent source is unavailable, such as x-ray and electron sources.


title:
Attempt frequency of magnetization in nanomagnets with thin-film
  geometry

abstract:
  Solving the stochastic Landau-Lifshitz-Gilbert equation numerically, we
investigate the effect of the potential landscape on the attempt frequency of
magnetization in nanomagnets with the thin-film geometry. Numerical estimates
of the attempt frequency are analyzed in comparison with theoretical
predictions from the Fokker-Planck equation for the Neel-Brown model. It is
found that for a nanomagnet with the thin-film geometry, theoretically
predicted values for the universal case are in excellent agreement with
numerical estimates.


title: Candidate Disk Wide Binaries in the Sloan Digital Sky Survey

abstract:
  Using SDSS Data Release 6, we construct two independent samples of candidate
stellar wide binaries selected as i) pairs of unresolved sources with angular
separation in the range 3'' - 16'', ii) common proper motion pairs with 5'' -
30'' angular separation, and make them publicly available. These samples are
dominated by disk stars, and we use them to constrain the shape of the
main-sequence photometric parallax relation M_r(r-i) and to study the
properties of wide binary systems. We estimate M_r(r-i) by searching for a
relation that minimizes the difference between distance moduli of primary and
secondary components of wide binary candidates. We model M_r(r-i) by a fourth
degree polynomial and determine the coefficients using Markov Chain Monte Carlo
fitting, independently for each sample. Aided by the derived photometric
parallax relation, we construct a series of high-quality catalogs of candidate
main-sequence binary stars. Using these catalogs, we study the distribution of
semi-major axes of wide binaries, a, in the 2,000 < a < 47,000 AU range. We
find the observations to be well described by the Opik distribution, f(a)~1/a,
for a<a_{break}, where a_{break} increases roughly linearly with the height Z
above the Galactic plane (a_{break}~12,300 Z[kpc]^0.7 AU). The number of wide
binary systems with 100 AU < a < a_{break}, as a fraction of the total number
of stars, decreases from 0.9% at Z=0.5 kpc to 0.5% at Z=3 kpc. The probability
for a star to be in a wide binary system is independent of its color. Given
this color, the companions of red components seem to be drawn randomly from the
stellar luminosity function, while blue components have a larger blue-to-red
companion ratio than expected from luminosity function.


title: Structure, Stability, Edge States and Aromaticity of Graphene Ribbons

abstract:
  We determine the stability, the geometry, the electronic and magnetic
structure of hydrogen-terminated graphene-nanoribbons edges as a function of
the hydrogen content of the environment by means of density functional theory.
Antiferromagnetic zigzag ribbons are stable only at extremely-low ultra-vacuum
pressures. Under more standard conditions, the most stable structures are the
mono- and di-hydrogenated armchair edges and a zigzag edge reconstruction with
one di- and two mono-hydrogenated sites. At high hydrogen-concentration
``bulk'' graphene is not stable and spontaneously breaks to form ribbons, in
analogy to the spontaneous breaking of graphene into small-width nanoribbons
observed experimentally in solution. The stability and the existence of exotic
edge electronic-states and/or magnetism is rationalized in terms of simple
concepts from organic chemistry (Clar's rule)


title:
Revisiting chameleon gravity - thin-shells and no-shells with
  appropriate boundary conditions

abstract:
  We derive analytic solutions of a chameleon scalar field $\phi$ that couples
to a non-relativistic matter in the weak gravitational background of a
spherically symmetric body, paying particular attention to a field mass $m_A$
inside of the body. The standard thin-shell field profile is recovered by
taking the limit $m_A*r_c \to \infty$, where $r_c$ is a radius of the body. We
show the existence of "no-shell" solutions where the field is nearly frozen in
the whole interior of the body, which does not necessarily correspond to the
"zero-shell" limit of thin-shell solutions. In the no-shell case, under the
condition $m_A*r_c \gg 1$, the effective coupling of $\phi$ with matter takes
the same asymptotic form as that in the thin-shell case. We study experimental
bounds coming from the violation of equivalence principle as well as
solar-system tests for a number of models including $f(R)$ gravity and find
that the field is in either the thin-shell or the no-shell regime under such
constraints, depending on the shape of scalar-field potentials. We also show
that, for the consistency with local gravity constraints, the field at the
center of the body needs to be extremely close to the value $\phi_A$ at the
extremum of an effective potential induced by the matter coupling.


title:
Impact of the electron-electron correlation on phonon dispersions:
  failure of LDA and GGA functionals in graphene and graphite

abstract:
  We compute electron-phonon coupling (EPC) of selected phonon modes in
graphene and graphite using various ab-initio methods. The inclusion of
non-local exchange-correlation effects within the GW approach strongly
renormalizes the square EPC of the A$'_1$ {\bf K} mode by almost 80$%$ with
respect to density functional theory in the LDA and GGA approximations. Within
GW, the phonon slope of the A$'_1$ {\bf K} mode is almost two times larger than
in GGA and LDA, in agreement with phonon dispersions from inelastic x-ray
scattering and Raman spectroscopy. The hybrid B3LYP functional overestimates
the EPC at {\bf K} by about 30%. Within the Hartree-Fock approximation, the
graphene structure displays an instability under a distortion following the
A$'_1$ phonon at {\bf K}.


title:
The Tsallis Entropy Barrier or the Roundness Barrier Based Dynamic
  Stochastic Resonance --A New Family of SR ?

abstract:
  The Tsallis entropy barrier or the roundness barrier based dynamic stochastic
resonance mechanisms are put forward and simulated. The systems with various
Tsallis q values exhibit the effects of emergence as a result of the
noise-induced cooperative phenomena.


title: Bell inequality for qubits based on the Cauchy-Schwarz inequality

abstract:
  We develop a systematic approach to establish Bell inequalities for qubits
based on the Cauchy-Schwarz inequality. We also use the concept of distinct
"roots" of Bell function to classify some well-known Bell inequalities for
qubits. As applications of the approach, we present three new and tight Bell
inequalities for four and three qubits, respectively.


title: Narrow escape and leakage of Brownian particles

abstract:
  Questions of flux regulation in biological cells raise renewed interest in
the narrow escape problem. The often inadequate expansions of the narrow escape
time are due to a not so well known fact that the boundary singularity of
Green's function for Poisson's equation with Neumann and mixed
Dirichlet-Neumann boundary conditions in three-dimensions contains a
logarithmic singularity. Using this fact, we find the second term in the
expansion of the narrow escape time and in the expansion of the principal
eigenvalue of the Laplace equation with mixed Dirichlet-Neumann boundary
conditions, with small Dirichlet and large Neumann parts. We also find the
leakage flux of Brownian particles that diffuse from a source to an absorbing
target on a reflecting boundary of a domain, if a small perforation is made in
the reflecting boundary.


title:
Factorization Method for d-Dimensional Isotropic Harmonic Oscillator and
  the Generalized Laguerre Polynomials

abstract:
  The factorization method of Infeld and Hull is applied to the radial
Schr\"{o}dinger equation for $d$-dimensional isotropic harmonic oscillator and
various ladder operators are defined. The radial energy eigenstates are
expressed in terms of the generalized Laguerre polynomials and their properties
are shown to follow from the expressions involving the ladder operators. In the
same way as the harmonic oscillator we also obtain the bound energy eigenstates
of the Morse oscillator.


title:
Inhomogeneous Phases in a Double-Exchange Magnet with Long Range Coulomb
  Interactions

abstract:
  We consider a model with competing double-exchange (ferromagnetic) and
super-exchange (anti-ferromagnetic) interactions in the regime where phase
separation takes place. The presence of a long range Coulomb interaction
frustrates a macroscopic phase separation, and favors microscopically
inhomogeneous configurations. We use the variational Hartree-Fock approach, in
conjunction with Monte-Carlo simulations to study the geometry of such
configurations in a two-dimensional system. We find that an array of diamond
shaped ferromagnetic droplets is the preferred configuration at low electronic
densities, while alternating ferromagnetic and anti-ferromagnetic diagonal
stripes emerge at higher densities. These findings are expected to be relevant
for thin films of colossal magneto-resistive manganates.


title: p-q-superstrings in Anti-de-Sitter space-time

abstract:
  We study a field theoretical model for p-q-superstrings in a fixed
Anti-de-Sitter background. We find that the presence of the negative
cosmological constant tends to decrease the core radius of the strings.
Moreover, the binding energy decreases with the increase of the absolute value
of the cosmological constant. Studying the effect of the p-q-strings on
Anti-de-Sitter space, we observe that the presence of the negative cosmological
constant tends to decrease the deficit angle as compared to asymptotically flat
space-time.


title: Multi-telescope timing of PSR J1518+4904

abstract:
  PSR J1518+4904 is one of only 9 known double neutron star systems. These
systems are highly valuable for measuring the masses of neutron stars,
measuring the effects of gravity, and testing gravitational theories. We
determine an improved timing solution for a mildly relativistic double neutron
star system, combining data from multiple telescopes. We set better constraints
on relativistic parameters and the separate masses of the system, and discuss
the evolution of PSR J1518+4904 in the context of other double neutron star
systems. PSR J1518+4904 has been regularly observed for more than 10 years by
the European Pulsar Timing Array (EPTA) network using the Westerbork, Jodrell
Bank, Effelsberg and Nancay radio telescopes. The data were analysed using the
updated timing software Tempo2. We have improved the timing solution for this
double neutron star system. The periastron advance has been refined and a
significant detection of proper motion is presented. It is not likely that more
post-Keplerian parameters, with which the individual neutron star masses and
the inclination angle of the system can be determined separately, can be
measured in the near future. Using a combination of the high-quality data sets
present in the EPTA collaboration, extended with the original GBT data, we have
constrained the masses in the system to m_p<1.17 msun and m_c>1.55 msun (95.4%
confidence), and the inclination angle of the orbit to be less than 47 degrees
(99%). From this we derive that the pulsar in this system possibly has one of
the lowest neutron star masses measured to date. From evolutionary
considerations it seems likely that the companion star, despite its high mass,
was formed in an electron-capture supernova.


title:
Spin Dynamics in Iron-based Layered Superconductor
  (La_{0.87}Ca_{0.13})FePO Revealed by ^{31}P and ^{139}La NMR Studies

abstract:
  We report ^{31}P and ^{139}La NMR studies of (La_{0.87}Ca_{0.13})FePO, which
is a family member of the recently discovered superconductor
LaFeAs(O_{1-x}F_x). In the normal state, Knight shift and $1/T_1T$ show that a
Fermi-liquid state with moderate ferromagnetic fluctuations emerges below 30K.
  From 1/T_1T of ^{31}P and ^{139}La, quasi-two dimensional electronic
structure is suggested, in which the FeP layer is more conductive than the LaO
layer. In the superconducting (SC) state, although a clear Meissner signal was
observed, 1/T_1T increases below T_c, in contrast to a decrease of 1/T_1T due
to the opening of a SC gap, suggesting that novel low-energy spin dynamics
develop in the SC state.


title: Sound Waves Excitation by Jet-Inflated Bubbles in Clusters of Galaxies

abstract:
  We show that repeated sound waves in the intracluster medium (ICM) can be
excited by a single inflation episode of an opposite bubble pair. To reproduce
this behavior in numerical simulations the bubbles should be inflated by jets,
rather than being injected artificially. The multiple sound waves are excited
by the motion of the bubble-ICM boundary that is caused by vortices inside the
inflated bubbles and the backflow (`cocoon') of the ICM around the bubble.
These sound waves form a structure that can account for the ripples observed in
the Perseus cooling flow cluster. We inflate the bubbles using slow massive
jets, with either a wide opening angle or that are precessing. The jets are
slow in the sense that they are highly sub-relativistic, $v_j \sim 0.01c-0.1c$,
and they are massive in the sense that the pair of bubbles carry back to the
ICM a large fraction of the cooling mass, i.e., $\sim 1-50 M_\odot \yr^{-1}$.
We use a two-dimensional axisymmetric (referred to as 2.5D) hydrodynamical
numerical code (VH-1).


title: Dynamics of grain ejection by sphere impact on a granular bed

abstract:
  The dynamics of grain ejection consecutive to a sphere impacting a granular
material is investigated experimentally and the variations of the
characteristics of grain ejection with the control parameters are
quantitatively studied. The time evolution of the corona formed by the ejected
grains is reported, mainly in terms of its diameter and height, and favourably
compared with a simple ballistic model. A key characteristic of the granular
corona is that the angle formed by its edge with the horizontal granular
surface remains constant during the ejection process, which again can be
reproduced by the ballistic model. The number and the kinetic energy of the
ejected grains is evaluated and allows for the calculation of an effective
restitution coefficient characterizing the complex collision process between
the impacting sphere and the fine granular target. The effective restitution
coefficient is found to be constant when varying the control parameters.


title: Fixed-Point Design of Generalized Comb Filters: A Statistical Approach

abstract:
  This paper is concerned with the problem of designing computationally
efficient Generalized Comb Filters (GCF). Basically, GCF filters are
anti-aliasing filters that guarantee superior performance in terms of
selectivity and quantization noise rejection compared to classical comb
filters, when used as decimation filters in multistage architectures. Upon
employing a partial polyphase (PP) architecture proposed in a companion paper,
we develop a sensitivity analysis in order to investigate the effects of the
coefficients' quantization on the frequency response of the designed filters.
We show that the sensitivity of the filter response to errors in the
coefficients is dependent on the particular split of the decimation factor
between the two sub-filters constituting the PP architecture. The sensitivity
analysis is then used for developing a fixed-point implementation of a sample
filter from the class of GCF filters, used as reference filter throughout the
paper. Finally, we present computer simulations in order to evaluate the
performance of the designed fixed-point filters.


title:
Duality Relation for the Hilbert Series of Almost Symmetric Numerical
  Semigroups

abstract:
  We derive the duality relation for the Hilbert series H(d^m;z) of almost
symmetric numerical semigroup S(d^m) combining it with its dual H(d^m;z^{-1}).
On this basis we establish the bijection between the multiset of degrees of the
syzygy terms and the multiset of the gaps F_j, generators d_i and their linear
combinations. We present the relations for the sums of the Betti numbers of
even and odd indices separately. We apply the duality relation to the simple
case of the almost symmetric semigroups of maximal embedding dimension, and
give the necessary and efficient conditions for minimal set d^m to generate
such semigroups.


title:
Light Stop Searches at the LHC in Events with One Hard Photon or Jet and
  Missing Energy

abstract:
  Low energy supersymmetric models provide a solution to the hierarchy problem
and also have the necessary ingredients to solve two of the most outstanding
issues in cosmology: the origin of the baryon asymmetry and the source of dark
matter. In the MSSM, weak scale generation of the baryon asymmetry may be
achieved in the presence of light stops, with masses lower than about 130 GeV.
Moreover, the proper dark matter density may be obtained in the stop-neutralino
co-annihilation region, where the stop-neutralino mass difference is smaller
than a few tens of GeV. Searches for scalar top quarks (stops) in pair
production processes at the Tevatron and at the Large Hadron Collider (LHC)
become very challenging in this region of parameters. At the LHC, however,
light stops proceeding from the decay of gluino pairs may be identified,
provided the gluino mass is smaller than about 900 GeV. In this article we
propose an alternative method for stop searches in the co-annihilation region,
based on the search for these particles in events with missing energy plus one
hard photon or jet. We show that this method is quite efficient and, when
complemented with ongoing Tevatron searches, allows to probe stop masses up to
about 160 GeV, fully probing the region of parameters consistent with
electroweak baryogenesis in the MSSM.


title: Dirac particle in gravitation field

abstract:
  Being considered is the motion of Dirac particle in gravitational field,
described by Kerr solution. It is proved, that evolution of the wave function
is determined by Hermitian Hamiltonian, if the concomitant reference frame is
involved.


title:
Understanding Dilepton Production in Heavy Ion Collisions by Vector
  Mesons of Different Varieties

abstract:
  A simple schematic model anchored on the notion of hadronic freedom inferred
from hidden local symmetry in the vector manifestation, the infinite tower of
vector mesons in holographic QCD and "stickiness" of $\pi\pi$ interactions
inferred from dispersion relations is used to describe the dileptons produced
in relativistic heavy ion collisions at PHENIX/RHIC. It is shown that due to
the near "blindness" of dileptons to Brown-Rho scaling, those dileptons with
invariant mass less than $m_\rho=770$ MeV come mostly from pion-composites that
we interpret as "transient $\rho$'s."


title:
Detailed Calculations of the Mass Spectrum for the Leptons after
  Supersymmetry Breaking in the Supersymmetric Standard Model: Cybersusy IV

abstract:
  This is the fourth of a series of four papers introducing cybersusy, which is
a new approach to supersymmetry breaking in the supersymmetric standard model.
This paper contains a brief summary, and then goes on to the calculation of the
propagators and masses for the leptons, using the cybersusy action deduced in
the three previous papers of this series. The results here are for the general
case of three flavours of leptons.


title: Application of the density functional theory to the fuel cell problem

abstract:
  The large-scale practical application of fuel cells in hydrogen economy is
possible only with a dramatic reduction of the cost coupled with a significant
improvement of the electrocatalytic properties of the electrodes. This goal can
be achieved through a rational design of new materials, which requires
understanding of the microscopic mechanisms underlying the electrocatalysis. We
discuss some applications of the density functional theory to this problem
using using alloying of Ru with Pt as the case in point. We provide some
details for Pt islets on Ru nanoparticles, for which our calculations explain
the high CO tolerance observed for such anodes of the fuel cell. We also
discuss energetics responsible for the stability of these islets on the
nanoparticles.


title: Markov paths, loops and fields

abstract:
  This is an extended version of a series of lectures given in St Flour. It
includes a discussion of relations between the occupation field of Markov loops
with the corresponding free field.


title: Boundaries of systolic groups

abstract:
  For all systolic groups we construct boundaries which are EZ--structures.
This implies the Novikov conjecture for torsion--free systolic groups. The
boundary is constructed via a system of distinguished geodesics in a systolic
complex, which we prove to have coarsely similar properties to geodesics in
CAT(0) spaces.


title: A Consistent Scenario for B to PS Decays

abstract:
  We consider B to PS decays where P stands for pseudoscalar and S for a heavy
(~1500 MeV) scalar meson. We achieve agreement with available experimental data
-- which includes a two orders of magnitude hierarchy -- assuming the scalars
mesons are two quark states. The contribution of the dipolar penguin operator
O_{11} is quantified.


title: Quantum state transfer with untuneable couplings

abstract:
  We present a general scheme for implementing bi-directional quantum state
transfer in a quantum swapping channel. Unlike many other schemes for quantum
computation and communication, our method does not require qubit couplings to
be switched on and off. The only control variable is the bias acting on
individual qubits. We show how to derive the parameters of the system (fixed
and variable) such that perfect state transfer can be achieved. Since these
parameters vary linearly with the pulse width, our scheme allows flexibility in
the time scales under which qubits evolve. Unlike quantum spin networks, our
scheme allows the transmission of several quantum states at a time, requiring
only a two qubit separation between quantum states. By pulsing the biases of
several qubits at the same time, we show that only eight bias control lines are
required to achieve state transfer along a channel of arbitrary length.
Furthermore, when the information to be transferred is purely classical in
nature, only three bias control lines are required, greatly simplifying the
circuit complexity.


title: Boolean complexes for Ferrers graphs

abstract:
  In this paper we provide an explicit formula for calculating the boolean
number of a Ferrers graph. By previous work of the last two authors, this
determines the homotopy type of the boolean complex of the graph. Specializing
to staircase shapes, we show that the boolean numbers of the associated Ferrers
graphs are the Genocchi numbers of the second kind, and obtain a relation
between the Legendre-Stirling numbers and the Genocchi numbers of the second
kind. In another application, we compute the boolean number of a complete
bipartite graph, corresponding to a rectangular Ferrers shape, which is
expressed in terms of the Stirling numbers of the second kind. Finally, we
analyze the complexity of calculating the boolean number of a Ferrers graph
using these results and show that it is a significant improvement over
calculating by edge recursion.


title: The arithmetic-geometric scaling spectrum for continued fractions

abstract:
  To compare continued fraction digits with the denominators of the
corresponding approximants we introduce the arithmetic-geometric scaling. We
will completely determine its multifractal spectrum by means of a number
theoretical free energy function and show that the Hausdorff dimension of sets
consisting of irrationals with the same scaling exponent coincides with the
Legendre transform of this free energy function. Furthermore, we identify the
asymptotic of the local behaviour of the spectrum at the right boundary point
and discuss a connection to the set of irrationals with continued fraction
digits exceeding a given number which tends to infinity.


title:
Modulated electronic configurations in selectively doped multilayered
  nanostructures

abstract:
  A simple theoretical model is proposed to describe the recent experimental
results on formation of induced superconducting state and anomalous tunneling
characteristics in selectively doped multilayered nanostructures based on
La$_2$CuO$_4$ perovskite. In particular, it is shown that the structure
composed from the nominally non-superconducting (undoped and overdoped) layers
turns to be superconducting with superconductivity confined to narrow regions
near the interfaces, in agreement with the experimental observations.


title: On a possibility of a UV finite N=8 supergravity

abstract:
  The Lorentz covariant all-loop counterterms built in the 4+32 on shell
superspace of N=8 supergravity imply that the theory is not UV finite.
Meanwhile, the relevant counterterms depending on the light-cone superfields in
4+16 superspace have not been constructed so far. Our first attempt to
construct them suggests that they may be incompatible with the covariant ones.
This would lead to a prediction of all-loop UV finiteness of the perturbative
S-matrix. Here we rely on the validity of the equivalence theorem for the
S-matrix in the light-cone gauge and Lorentz covariant gauges, which requires
the absence of BRST anomalies. We discuss the status of N=8 SU(8) and E7
anomalies. It remains an outstanding problem to construct the light-cone
counterterms or to confirm our current conclusion.


title: Gamma-invariant ideals in Iwasawa algebras

abstract:
  Let kG be the completed group algebra of a uniform pro-p group G with
coefficients in a field k of characteristic p. We study right ideals I in kG
that are invariant under the action of another uniform pro-p group Gamma. We
prove that if I is non-zero then an irreducible component of the characteristic
support of kG/I must be contained in a certain finite union of rational linear
subspaces of Spec gr kG. The minimal codimension of these subspaces gives a
lower bound on the homological height of I in terms of the action of a certain
Lie algebra on G/G^p. If we take Gamma to be G acting on itself by conjugation,
then Gamma-invariant right ideals of kG are precisely the two-sided ideals of
kG, and we obtain a non-trivial lower bound on the homological height of a
possible non-zero two-sided ideal. For example, when G is open in SL_n(\Zp)
this lower bound equals 2n - 2. This gives a significant improvement of the
results of Ardakov, Wei and Zhang on reflexive ideals in Iwasawa algebras.


title: Hydroanalysis of Animal Lysozymes c and Human Defensins a

abstract:
  Proteins appear to be the most dramatic natural example of self-organized
criticality (SOC), a concept that explains many otherwise apparently unlikely
phenomena. Protein functionality is dominated by long range
hydro(phobic/philic) interactions which both drive protein compaction and
mediate protein-protein interactions. In contrast to previous reductionist
short range hydrophobicity scales, the holistic Moret-Zebende hydrophobicity
scale represents a hydroanalytic tool that bioinformatically quantifies SOC in
a way fully compatible with evolution. Hydroprofiling identifies chemical
trends in the activities and substrate binding abilities of model enzymes and
antibiotic animal lysozymes c and antibiotic human defensins, which have been
the subject of tens of thousands of experimental studies. The analysis is
simple and easily performed, and immediately yields insights not obtainable by
traditional methods based on short-range real-space interactions, as described
either by classical force fields (CFF) used in molecular dynamics simulations
(MDS), or hydrophobicity scales based on transference energies from water to
organic solvents.


title: The impact of dust on the scaling properties of galaxy clusters

abstract:
  We investigate the effect of dust on the scaling properties of galaxy
clusters based on hydrodynamic N-body simulations of structure formation. We
have simulated five dust models plus a radiative cooling and adiabatic models
using the same initial conditions for all runs. The numerical implementation of
dust was based on the analytical computations of Montier and Giard (2004). We
set up dust simulations to cover different combinations of dust parameters that
put in evidence the effects of size and abundance of dust grains. Comparing our
radiative plus dust cooling runs to a purely radiative cooling simulation we
find that dust has an impact on cluster scaling relations. It mainly affects
the normalisation of the scalings (and their evolution), whereas it introduces
no significant differences on their slopes. The strength of the effect depends
critically on the dust abundance and grain size parameters as well as on the
cluster scaling. Indeed, cooling due to dust is effective at the cluster regime
and has a stronger effect on the "baryon driven" statistical properties of
clusters such as $L_{\rm X}-M$, $Y- M$, $S-M$ scaling relations. Major
differences, relative to the radiative cooling model, are as high as 25% for
the $L_{\rm X}-M$ normalisation, and about 10% for the $Y-M$ and $S-M$
normalisations at redshift zero. On the other hand, we find that dust has
almost no impact on the "dark matter driven" $T_{\rm mw}-M$ scaling relation.
The effects are found to be dependent in equal parts on both dust abundances
and grain sizes distributions for the scalings investigated in this paper.
Higher dust abundances and smaller grain sizes cause larger departures from the
radiative cooling (i.e. with no dust) model.


title: Capacity of Symmetric K-User Gaussian Very Strong Interference Channels

abstract:
  This paper studies a symmetric K user Gaussian interference channel with K
transmitters and K receivers. A "very strong" interference regime is derived
for this channel setup. A "very strong" interference regime is one where the
capacity region of the interference channel is the same as the capacity region
of the channel with no interference. In this regime, the interference can be
perfectly canceled by all the receivers without incurring any rate penalties. A
"very strong" interference condition for an example symmetric K user
deterministic interference channel is also presented.


title:
Frequency-domain calculation of the self force: the high-frequency
  problem and its resolution

abstract:
  The mode-sum method provides a practical means for calculating the self force
acting on a small particle orbiting a larger black hole. In this method, one
first computes the spherical-harmonic $l$-mode contributions $F^{\mu}_l$ of the
"full force" field $F^{\mu}$, evaluated at the particle's location, and then
sums over $l$ subject to a certain regularization procedure. In the
frequency-domain variant of this scheme the quantities $F^{\mu}_l$ are obtained
by fully decomposing the particle's self field into Fourier-harmonic modes $l m
\omega$, calculating the contribution of each such mode to $F^{\mu}_l$, and
then summing over $\omega$ and $m$ for given $l$. This procedure has the
advantage that one only encounters {\it ordinary} differential equations.
However, for eccentric orbits, the sum over $\omega$ is found to converge badly
at the particle's location. This problem (reminiscent of the familiar Gibbs
phenomenon) results from the discontinuity of the time-domain $F^{\mu}_l$ field
at the particle's worldline. Here we propose a simple and practical method to
resolve this problem. The method utilizes the {\it homogeneous} modes $l m
\omega$ of the self field to construct $F^{\mu}_l$ (rather than the
inhomogeneous modes, as in the standard method), which guarantees an
exponentially-fast convergence to the correct value of $F^{\mu}_l$, even at the
particle's location. We illustrate the application of the method with the
example of the monopole scalar-field perturbation from a scalar charge in an
eccentric orbit around a Schwarzschild black hole. Our method, however, should
be applicable to a wider range of problems, including the calculation of the
gravitational self-force using either Teukolsky's formalism, or a direct
integration of the metric perturbation equations.


title: A new secant method for unconstrained optimization

abstract:
  We present a gradient-based algorithm for unconstrained minimization derived
from iterated linear change of basis. The new method is equivalent to linear
conjugate gradient in the case of a quadratic objective function. In the case
of exact line search it is a secant method. In practice, it performs comparably
to BFGS and DFP and is sometimes more robust.


title: Evidence of convective rolls in a sunspot penumbra

abstract:
  aims: We study the recently discovered twisting motion of bright penumbral
filaments with the aim of constraining their geometry and the associated
magnetic field. methods: A large sunspot located $40\degr$ from disk center was
observed at high resolution with the 1-m Swedish Solar Telescope. Inversions of
multi-wavelength polarimetric data and speckle reconstructed time series of
continuum images were used to determine proper motions, as well as the velocity
and magnetic structure in penumbral filaments. results: The continuum movie
reveals apparent lateral motions of bright and dark structures inside bright
filaments oriented parallel to the limb, confirming recent Hinode results. In
these filaments we measure upflows of $\approx 1.1 \mathrm{km/s}$ on their
limbward side and weak downflows on their centerward side. The magnetic field
in them is significantly weaker and more horizontal than in the adjacent dark
filaments. conclusions: The data indicate the presence of vigorous convective
rolls in filaments with a nearly horizontal magnetic field. These are separated
by filaments harbouring stronger, more vertical fields. Because of reduced gas
pressure, we see deeper into the latter. When observed near the limb, the
disk-centerward side of the horizontal-field filaments appear bright due to the
\textit{hot wall} effect known from faculae. We estimate that the convective
rolls transport most of the energy needed to explain the penumbral radiative
flux.


title: Thermal Relics in Hidden Sectors

abstract:
  Dark matter may be hidden, with no standard model gauge interactions. At the
same time, in WIMPless models with hidden matter masses proportional to hidden
gauge couplings squared, the hidden dark matter's thermal relic density may
naturally be in the right range, preserving the key quantitative virtue of
WIMPs. We consider this possibility in detail. We first determine
model-independent constraints on hidden sectors from Big Bang nucleosynthesis
and the cosmic microwave background. Contrary to conventional wisdom, large
hidden sectors are easily accommodated. A flavour-free version of the standard
model is allowed if the hidden sector is just 30% colder than the observable
sector after reheating. Alternatively, if the hidden sector contains a
1-generation version of the standard model with characteristic mass scale below
1 MeV, even identical reheating temperatures are allowed. We then analyze
hidden sector freezeout in detail for a concrete model, solving the Boltzmann
equation numerically and understanding the results from both observable and
hidden sector points of view. We find that WIMPless dark matter indeed obtains
the correct relic density for masses in the range keV < m_X < TeV. The upper
bound results from the requirement of perturbativity, and the lower bound
assumes that the observable and hidden sectors reheat to the same temperature
and is raised to the MeV scale if the hidden sector is 10 times colder.
WIMPless dark matter therefore generalizes the WIMP paradigm to the largest
mass range possible for viable thermal relics and provides a unified framework
for exploring dark matter signals across nine orders of magnitude in dark
matter mass.


title: Fitting Martingales To Given Marginals

abstract:
  We consider the problem of finding a real valued martingale fitting specified
marginal distributions. For this to be possible, the marginals must be
increasing in the convex order and have constant mean. We show that, under the
extra condition that they are weakly continuous, the marginals can always be
fitted in a unique way by a martingale which lies in a particular class of
strong Markov processes.
  It is also shown that the map that this gives from the sets of marginal
distributions to the martingale measures is continuous. Furthermore, we prove
that it is the unique continuous method of fitting martingale measures to the
marginal distributions.


title:
Creation of high-quality long-distance entanglement with flexible
  resources

abstract:
  We present a quantum repeater protocol that generates the elementary segments
of entangled photons through the communication of qubus in coherent states. The
input photons at the repeater stations can be in arbitrary states to save the
local state preparation time for the operations. The flexibility of the scheme
accelerates the generation of the elementary segments (close to the exact Bell
states) to a high rate for practical quantum communications. The entanglement
connection to long distances is simplified and sped up, possibly realizing an
entangled pair of high quality within the time in the order of that for
classical communication between two far-away locations.


title: The Penrose Transform for Complex Projective Space

abstract:
  Various complexes of differential operators are constructed on complex
projective space via the Penrose transform, which also computes their
cohomology.


title: A multi-etiology model of systemic degeneration in schizophrenia

abstract:
  We discuss the possibility of multiple underlying etiologies of the condition
currently labeled as schizophrenia. We support this hypothesis with a
theoretical model of the prefrontal-limbic system. We show how the dynamical
behavior of this model depends on an entire set of physiological parameters,
representing synaptic strengths, vulnerability to stress-induced cortisol,
dopamine regulation and rates of autoantibody production. Malfunction of
different such parameters produces similar outward dysregulation of the system,
which may readily lead to diagnosis difficulties in a clinician's office. We
further place this paradigm within the contexts of pathophysiology and of
antipsychotic pharmacology. We finally propose brain profiling as the future
quantitative diagnostic toolbox that agrees with a multiple etiologies
hypothesis of schizophrenia.


title: The 21cm Power Spectrum After Reionization

abstract:
  We discuss the 21cm power spectrum (PS) following the completion of
reionization. In contrast to the reionization era, this PS is proportional to
the PS of mass density fluctuations, with only a small modulation due to
fluctuations in the ionization field on scales larger than the mean-free-path
of ionizing photons. We derive the form of this modulation, and demonstrate
that its effect on the 21cm PS will be smaller than 1% for physically plausible
models of damped Ly-alpha systems. In contrast to the 21cm PS observed prior to
reionization, in which HII regions dominate the ionization structure, the
simplicity of the 21cm PS after reionization will enhance its utility as a
cosmological probe by removing the need to separate the PS into physical and
astrophysical components. As a demonstration, we consider the Alcock-Paczynski
test and show that the next generation of low-frequency arrays could measure
the angular distortion of the PS at the percent level for z~3-5.


title: On Stability of Pseudo-Conformal Blowup for L^2-critical Hartree NLS

abstract:
  We consider $L^2$-critical focusing nonlinear Schroedinger equations with
Hartree type nonlinearity $$i \pr_t u = -\DD u - \big (\Phi \ast |u|^2 \big) u
\quad {in $\RR^4$},$$ where $\Phi(x)$ is a perturbation of the convolution
kernel $|x|^{-2}$. Despite the lack of pseudo conformal invariance for this
equation, we prove the existence of critical mass finite-time blowup solutions
$u(t,x)$ that exhibit the pseudo-conformal blowup rate $$ \| \nabla u(t)
\|_{L^2_x} \sim \frac{1}{|t|} \quad {as} \quad t \nearrow 0 . $$ Furthermore,
we prove the finite-codimensional stability of this conformal blow up, by
extending the nonlinear wave operator construction by Bourgain and Wang (see
\cite{Bourgain+Wang1997}) to $L^2$-critical Hartree NLS.


title: Networking in the Physical World

abstract:
  In this work we propose a network meta-architecture based on fundamental laws
of physics and a physical model of computation. This meta-architecture may be
used to frame discussions about novel network architectures as well as
cross-layer alterations to the canonical network stack.


title: Electromagnetic Transition Form Factors of Nucleon Resonances

abstract:
  Recent measurements of nucleon resonance transition form factors with CLAS at
Jefferson Lab are discussed. The new data resolve a long-standing puzzle of the
nature of the Roper resonance, and confirm the assertion of the symmetric
constituent quark model of the Roper as the first radial excitation of the
nucleon. The data on $n\pi^+$ production at high $Q^2$ confirm the slow fall
off of the $S_{11}(1535)$ transition form factor with $Q^2$, and better
constrain the branching ratios $\beta_{N\pi}=0.50$ and $\beta_{N\eta}=0.45$.
Also, new results on the transition amplitudes for the $D_{13}(1520)$ resonance
are presented showing a rapid change from helicity 3/2 dominance seen at the
real photon point to helicty 1/2 dominance at higher $Q^2$.


title:
Deformed boson-fermion correspondence, Q-bosons, and topological strings
  on the conifold

abstract:
  We consider two different physical systems for which the basis of the Hilbert
space can be parametrized by Young diagrams: free complex fermions and the
phase model of strongly correlated bosons. Both systems have natural,
well-known deformations parametrized by a parameter Q: the former one is
related to the deformed boson-fermion correspondence introduced by N. Jing,
while the latter is the so-called Q-boson, arising also in the context of
quantum groups. These deformations are equivalent and can be realized in the
same way in the algebra of Hall-Littlewood symmetric functions. Without a
deformation, these reduce to Schur functions, which can be used to construct a
generating function of plane partitions, reproducing a topological string
partition function on $C^3$. We show that a deformation of both systems leads
then to a deformed generating function, which reproduces topological string
partition function of the conifold, with the deformation parameter Q identified
with the size of $P^1$. Similarly, a deformation of the fermion one-point
function results in the A-brane partition function on the conifold.


title: Parent Phases of Doped Mott Insulators: A Cluster DMFT Study

abstract:
  We investigate the insulating phases of a frustrated Hubbard model in its
strong coupling regime at half-filling. We pay special attention to all the
symmetry breaking instabilities that can be described by Dynamical Mean Field
Theory (DMFT) on a square plaquette. We identify several mean-field solutions,
two Neel states breaking the SU(2) symmetry, a dimer phase and a Mott insulator
which doesn't break any symmetry. The singlet to singlet fluctuations soften
dramatically in the latter phase, giving rise to dimerization fluctuations as
well as chiral fluctuations that are both low-lying. We present a simple
picture of the different DMFT states and their evolution with frustration.


title:
Local Coarse-grained Approximation to Path Integral Monte Carlo
  Integration for Fermion Systems

abstract:
  An approximate treatment of exchange in finite-temperature path integral
Monte Carlo simulations for fermions has been proposed. In this method, some of
the fine details of density matrix due to permutations have been smoothed over
or averaged out by using the coarse-grained approximation. The practical
usefulness of the method is tested for interacting fermions in a three
dimensional harmonic well. The results show that, the present method not only
reduces the sign fluctuation of the density matrix, but also avoid the fermion
system collapsing into boson system at low temperatures. The method is
substantiated to be exact when applied to free particles.


title: Noncommutative BTZ Black Hole in Polar Coordinates

abstract:
  Based on the equivalence between the three dimensional gravity and the
Chern-Simons theory, we obtain a noncommutative BTZ black hole solution as a
solution of $U(1,1)\times U(1,1)$ noncommutative Chern-Simons theory using the
Seiberg-Witten map. The Seiberg-Witten map is carried out in a noncommutative
polar coordinates whose commutation relation is equivalent to the usual
canonical commutation relation in the rectangular coordinates up to first order
in the noncommutativity parameter $\theta$. The solution exhibits a
characteristic of noncommutative polar coordinates in such a way that the
apparent horizon and the Killing horizon coincide only in the non-rotating
limit showing the effect of noncommutativity between the radial and angular
coordinates.


title:
Magnetic and charge transport properties of the Na-based Os oxide
  pyrochlore

abstract:
  Na-based osmium oxide pyrochlore was synthesized for the first time by an
ion-exchange method. KOs2O6 was used as a host compound. Elelectron probe
micro-analysis, synchrotron x-ray diffraction analysis, and thermo-gravimetric
analysis confirmed its structure not as the beta-type but as the defect-type
pyrochlore. The composition was identified as Na1.4Os2O6.H2O. Electrical
resistivity, heat capacity, and magnetization measurements of the
polycrystalline Na1.4Os2O6.H2O clarified absence of superconductivity above 2
K, being in contrast to what were found for the beta-pyrochlore AOs2O6 (A = Cs,
Rb, K). Sommerfeld coefficient of 22 mJ K-2 mol-1 of Na1.4Os2O6.H2O was
smallest among those of AOs2O6. A magnetic anomaly at ~57 K and possible
associated magnetoresistance (+3.7 % at 2 K in 70 kOe) were found.


title: Reducing the Variance of Likelihood Ratio Greeks with Monte Carlo

abstract:
  We investigate the use of Antithetic Variables, Control Variates and
Importance Sampling to reduce the statistical errors of option sensitivities
calculated with the Likelihood Ratio Method in Monte Carlo. We show how
Antithetic Variables solve the well-known problem of the divergence of the
variance of Delta for short maturities and small volatilities. With numerical
examples within a Gaussian Copula framework, we show how simple Control
Variates and Importance Sampling strategies provide computational savings up to
several orders of magnitude.


title:
Equivalence Classes of Boundary Conditions in Gauge Theory on $Z_3$
  Orbifold

abstract:
  We study equivalence classes of boundary conditions in gauge theory on the
orbifold $T^2/Z_3$. Orbifold conditions and those gauge transformation
properties are given and the gauge equivalence is understood by the Hosotani
mechanism. Mode expansions are carried out for six-dimensional $Z_3$ singlet
fields and a $Z_3$ triplet field, and the one-loop effective potential for
Wilson line phases is calculated.


title: Distortion elements in $Diff^\infty(R/Z)$

abstract:
  We consider the group of smooth diffeomorphisms of the circle. We show that
any recurrent $f$ (in the sense that $\{f^n\}_{n \in Z}$ is not discrete) is in
fact a distortion element (in the sense that its iterates can be written as
short compositions involving finitely many smooth diffeomorphisms). Thus
rotations are distortion elements.


title: Can local bulk effects explain the galactic dark matter?

abstract:
  We obtain the virial theorem within the context of a brane-world model
without mirror symmetry or any form of junction condition. Taking a constant
curvature bulk (neglecting non-local bulk effects), the local bulk effects
generate a geometrical mass, contributing to the gravitational energy which may
be used to explain the virial mass discrepancy in clusters of galaxies. We fix
the parameter of this model in agreement with observational data.


title: Khovanov homology, open books, and tight contact structures

abstract:
  We define the reduced Khovanov homology of an open book (S,h), and we
identify a distinguished "contact element" in this group which may be used to
establish the tightness or non-fillability of contact structures compatible
with (S,h). Our construction generalizes the relationship between the reduced
Khovanov homology of a link and the Heegaard Floer homology of its branched
double cover. As an application, we give combinatorial proofs of tightness for
several contact structures which are not Stein-fillable. Lastly, we investigate
a comultiplication structure on the reduced Khovanov homology of an open book
which parallels the comultiplication on Heegaard Floer homology defined
previously by the first author.


title: Decomposable Principal Component Analysis

abstract:
  We consider principal component analysis (PCA) in decomposable Gaussian
graphical models. We exploit the prior information in these models in order to
distribute its computation. For this purpose, we reformulate the problem in the
sparse inverse covariance (concentration) domain and solve the global
eigenvalue problem using a sequence of local eigenvalue problems in each of the
cliques of the decomposable graph. We demonstrate the application of our
methodology in the context of decentralized anomaly detection in the Abilene
backbone network. Based on the topology of the network, we propose an
approximate statistical graphical model and distribute the computation of PCA.


title: Axisymmetric Magnetorotational Instability in Viscous Accretion Disks

abstract:
  Axisymmetric magnetorotational instability (MRI) in viscous accretion disks
is investigated by linear analysis and two-dimensional nonlinear simulations.
The linear growth of the viscous MRI is characterized by the Reynolds number
defined as $R_{\rm MRI} \equiv v_A^2/\nu\Omega $, where $v_A$ is the Alfv{\'e}n
velocity, $\nu$ is the kinematic viscosity, and $\Omega$ is the angular
velocity of the disk. Although the linear growth rate is suppressed
considerably as the Reynolds number decreases, the nonlinear behavior is found
to be almost independent of $R_{\rm MRI}$. At the nonlinear evolutionary stage,
a two-channel flow continues growing and the Maxwell stress increases until the
end of calculations even though the Reynolds number is much smaller than unity.
A large portion of the injected energy to the system is converted to the
magnetic energy. The gain rate of the thermal energy, on the other hand, is
found to be much larger than the viscous heating rate. Nonlinear behavior of
the MRI in the viscous regime and its difference from that in the highly
resistive regime can be explained schematically by using the characteristics of
the linear dispersion relation. Applying our results to the case with both the
viscosity and resistivity, it is anticipated that the critical value of the
Lundquist number $S_{\rm MRI} \equiv v_A^2/\eta\Omega$ for active turbulence
depends on the magnetic Prandtl number $S_{{\rm MRI},c} \propto Pm^{1/2}$ in
the regime of $Pm \gg 1$ and remains constant when $Pm \ll 1$, where $Pm \equiv
S_{\rm MRI}/R_{\rm MRI} = \nu/\eta$ and $\eta$ is the magnetic diffusivity.


title:
The Nature of a Cosmic-Ray Accelerator, CTB37 B, Observed with Suzaku
  and Chandra

abstract:
  We report on Suzaku and Chandra observations of the young supernova remnant
CTB37B, from which TeV gamma-rays were detected by the H.E.S.S. Cherenkov
telescope. The 80 ks Suzaku observation provided us with a clear image of
diffuse emission and high-quality spectra. The spectra revealed that the
diffuse emission is comprised of thermal and non-thermal components. The
thermal component can be represented by an NEI model with a temperature, a
pre-shock electron density and an age of 0.9(0.7-1.1) keV, 0.4(0.3-0.5) cm^{-3}
and 650(350-3150) yr, respectively. This suggests that the explosion of CTB37B
occurred in a low-density space. A non-thermal power-law component was found
from the southern region of CTB37B. Its photon index of ~1.5 and a high
roll-off energy (>15 keV) indicate efficient cosmic-ray acceleration. A
comparison of this X-ray spectrum with the TeV gamma-ray spectrum leads us to
conclude that the TeV gamma-ray emission seems to be powered by either
multi-zone Inverse Compton scattering or the decay of neutral pions. The point
source resolved by Chandra near the shell is probably associated with CTB37B,
because of the common hydrogen column density with the diffuse thermal
emission. Spectral and temporal characteristics suggest that this source is a
new anomalous X-ray pulsar.


title: Le probl\`eme des diviseurs pour des formes binaires de degr\'e 4

abstract:
  We study the average order of the divisor function, as it ranges over the
values of binary quartic forms that are reducible over the rationals.


title:
A Moving Bump in a Continuous Manifold: A Comprehensive Study of the
  Tracking Dynamics of Continuous Attractor Neural Networks

abstract:
  Understanding how the dynamics of a neural network is shaped by the network
structure, and consequently how the network structure facilitates the functions
implemented by the neural system, is at the core of using mathematical models
to elucidate brain functions. This study investigates the tracking dynamics of
continuous attractor neural networks (CANNs). Due to the translational
invariance of neuronal recurrent interactions, CANNs can hold a continuous
family of stationary states. They form a continuous manifold in which the
neural system is neutrally stable. We systematically explore how this property
facilitates the tracking performance of a CANN, which is believed to have clear
correspondence with brain functions. By using the wave functions of the quantum
harmonic oscillator as the basis, we demonstrate how the dynamics of a CANN is
decomposed into different motion modes, corresponding to distortions in the
amplitude, position, width or skewness of the network state. We then develop a
perturbative approach that utilizes the dominating movement of the network's
stationary states in the state space. This method allows us to approximate the
network dynamics up to an arbitrary accuracy depending on the order of
perturbation used. We quantify the distortions of a Gaussian bump during
tracking, and study their effects on the tracking performance. Results are
obtained on the maximum speed for a moving stimulus to be trackable and the
reaction time for the network to catch up with an abrupt change in the
stimulus.


abstract:
  The evolution of the phase space density of particle beams in external fields
is found proceeding from the continuity equation in the six-dimensional (6D)
phase space (mu-space). The Robinson theorem, which includes the Liouville
theorem as a special case, was proved in a more simple and consistent
alternative way valid for arbitrary external fields, averaged fields of the
beam (self-generated electro-magnetic fields except intrabeam scattering) and
arbitrary frictional forces (linear, nonlinear). It includes particle
accelerators as a special case. The limits of the applicability of the Robinson
theorem in case of cooling of excited ions having a finite living time are
presented.


title:
A Rejoinder to Mackintosh and some Remarks on the Concept of General
  Intelligence

abstract:
  In 2000 Nicholas J. Mackintosh (2000) published an article in "Nature"
referring to the concept of general intelligence ("g") claiming that there is
clear empirical evidence for the existence of the g factor and psychologists
are "united in their support of g". Surprisingly, his view remained yet
unchallenged although this issue is by no means as clear-cut as Mackintosh
argues. Let us therefore attempt to clarify some common but unfortunately major
misconceptions about g, which Mackintosh, following Jensen's (1998) precedent,
recounted in his "Nature" article. The bottom line is that Spearman's g does
not exist, that this has been known and acknowledged by leading scholars
(Guttman, 1992; Thurstone, 1947) of factor analysis for decades so that the
task of objectively defining human intelligence remains unfinished.


title: The I^G J^{PC}=0^+ 1^{-+} Tetraquark State

abstract:
  We study the tetraquark state with I^G J^{PC} = 0^+ 1^{-+} in the QCD sum
rule. We exhaust all possible flavor structures by using a diquark-antidiquark
construction and find that the flavor structure 3*6+6*3 is preferred. There are
altogether four independent currents which have the quark contents q s \bar q
\bar s. By using both the Shifman-Vainshtein-Zakharov (SVZ) sum rule and the
finite energy sum rule, these currents lead to mass estimates around 1.8 - 2.1
GeV, where the uncertainty is due to the mixing of two single currents. Its
possible decay modes are S-wave b_1(1235) \eta and b_1(1235) \eta^\prime, and
P-wave KK, \eta \eta, \eta \eta^\prime and \eta^\prime \eta^\prime, etc. The
decay width is around 150 MeV through a rough estimation.


title: Diffusion in confined geometries

abstract:
  Diffusive transport of particles or, more generally, small objects is a
ubiquitous feature of physical and chemical reaction systems. In configurations
containing confining walls or constrictions transport is controlled both by the
fluctuation statistics of the jittering objects and the phase space available
to their dynamics. Consequently, the study of transport at the macro- and
nanoscales must address both Brownian motion and entropic effects. With this
survey we report on recent advances in the theoretical and numerical
investigation of stochastic transport occurring either in micro-sized
geometries of varying cross section or in narrow channels wherein the diffusing
particles are hindered from passing each other (single file diffusion). For
particles undergoing biased diffusion in static suspension media enclosed by
confining geometries, transport exhibits intriguing features such as (i) a
decrease of nonlinear mobility with increasing temperature or, also, (ii) a
broad excess peak of the effective diffusion above the free diffusion limit.
These paradoxical aspects can be understood in terms of entropic contributions
resulting from the restricted dynamics in phase space. If, in addition, the
suspension medium is subjected to external, time-dependent forcing,
rectification or segregation of the diffusing Brownian particles becomes
possible. Likewise, the diffusion in very narrow, spatially modulated channels
gets modified via contact particle-particle interactions, which induce
anomalous sub-diffusion. The effective sub-diffusion constant for a driven
single file also develops a resonance-like structure as a function of the
confining coupling constant.


title: The dynamics of internal working surfaces in MHD jets

abstract:
  The dynamical effects of magnetic fields in models of radiative, Herbig-Haro
(HH) jets have been studied in a number of papers. For example, magnetized,
radiative jets from variable sources have been studied with axisymmetric and 3D
numerical simulations. In this paper, we present an analytic model describing
the effect of a toroidal magnetic field on the internal working surfaces that
result from a variability in the ejection velocity. We find that for parameters
appropriate for HH jets the forces associated with the magnetic field dominate
over the gas pressure force within the working surfaces. Depending on the ram
pressure radial cross section of the jet, the magnetic field can produce a
strong axial pinch, or, alternatively, a broadening of the internal working
surfaces. We check the validity of the analytic model with axisymmetric
numerical simulations of variable, magnetized jets.


title: Rotating Black Branes in Brans-Dicke-Born-Infeld Theory

abstract:
  In this paper, we present a new class of charged rotating black brane
solutions in the higher dimensional Brans-Dicke-Born-Infeld theory and
investigate their properties. Solving the field equations directly is a
non-trivial task because they include the second derivatives of the scalar
field. We remove this difficulty through a conformal transformation. Also, we
find that the suitable Lagrangian of Einstein-Born-Infeld-dilaton gravity is
not the same as presented in \cite{DHSR}. We show that the given solutions can
present black brane, with inner and outer event horizons, an extreme black
brane or a naked singularity provided the parameters of the solutions are
chosen suitably. These black brane solutions are neither asymptotically flat
nor (anti)-de Sitter. Then we calculate finite Euclidean action, the conserved
and thermodynamic quantities through the use of counterterm method. Finally, we
argue that these quantities satisfy the first law of thermodynamics, and the
entropy does not follow the area law.


title: Spin Bath Decoherence Mediated by Phonons

abstract:
  We introduce an exactly solvable model to study decoherence of a central spin
interacting with a spin bath where the coupling is mediated by phonons which we
assume to be in a coherent state or thermal distribution. For the coherent
state case, we find that the decoherence factor decays in a Gaussian fashion
and it becomes independent of the phonon frequencies at short times. If the
phonon energies are much larger than spin-phonon coupling or bath spins are
fully polarized, decoherence time becomes independent of the initial phonon
state. For the thermal state case, phonons play more important role in
decoherence with increasing temperature. We also discuss possible effects of
the temperature on spin bath contribution to decoherence.


title: A spline interpretation of Eulerian numbers

abstract:
  In this paper, we explore the interrelationship between Eulerian numbers and
B splines. Specifically, using B splines, we give the explicit formulas of the
refined Eulerian numbers, and descents polynomials. Moreover, we prove that the
coefficients of descent polynomials $D_d^n(t)$ are log-concave. This paper also
provides a new approach to study Eulerian numbers and descent polynomials.


title: Dynamically Generated Double Occupancy as a Probe of Cold Atom Systems

abstract:
  The experimental investigation of quantum phases in optical lattice systems
provides major challenges. Recently, dynamical generation of double occupancy
via modulation of the hopping amplitude t has been used to characterize the
strongly correlated phase of fermionic atoms. Here, we want to validate this
experimental technique with a theoretical study of the driven Hubbard model
using analytic methods. We find that conclusive evidence for a Mott phase can
be inferred from such a measurement, provided that sufficiently low
temperatures kT<<t can be reached.


title: Ricci flow, quantum mechanics and gravity

abstract:
  It has been argued that, underlying any given quantum-mechanical model, there
exists at least one deterministic system that reproduces, after
prequantisation, the given quantum dynamics. For a quantum mechanics with a
complex d-dimensional Hilbert space, the Lie group SU(d) represents classical
canonical transformations on the projective space CP^{d-1} of quantum states.
Let R stand for the Ricci flow of the manifold SU(d-1) down to one point, and
let P denote the projection from the Hopf bundle onto its base CP^{d-1}. Then
the underlying deterministic model we propose here is the Lie group SU(d),
acted on by the operation PR. Finally we comment on some possible consequences
that our model may have on a quantum theory of gravity.


title: Cluster-tilted algebras and their intermediate coverings

abstract:
  We construct the intermediate coverings of cluster-tilted algebras by
defining the generalized cluster categories. These generalized cluster
categories are Calabi-Yau triangulated categories with fraction CY-dimension
and have also cluster tilting objects (subcategories). Furthermore we study the
representations of these intermediate coverings of cluster-tilted algebras.


title:
Spin squeezing of a cold atomic ensemble with the nuclear spin of
  one-half

abstract:
  To establish an applicable system for advanced quantum information processing
between light and atoms, we have demonstrated the quantum non-demolition (QND)
measurement with a collective spin of cold ytterbium atoms (171Yb), and
observed 1.8 (-1.5, +2.4) dB spin squeezing. Since a 171Yb atom has only a
nuclear spin of 1/2 in the ground state, the system is the simplest spin
ensemble and robust against decoherence. We used very short pulses with the
width of 100 ns, so the interaction time became much shorter than the
decoherence time, which is important for multi-step quantum information
processing.


title:
Viscosity Bound, Causality Violation and Instability with Stringy
  Correction and Charge

abstract:
  Recently, it has been shown that if we consider the higher derivative
correction, the viscosity bound conjectured to be $\eta/s=1/4\pi$ is violated
and so is the causality. In this paper, we consider medium effect and the
higher derivative correction simultaneously by adding charge and Gauss-Bonnet
terms. We find that the viscosity bound violation is not changed by the charge.
However, we find that two effects together create another instability for large
momentum regime. We argue the presence of tachyonic modes and show it
numerically. The stability of the black brane requires the Gauss-Bonnet
coupling constant $\lambda$($=2\alpha'/l^2$) to be smaller than 1/24. We draw a
phase diagram relevant to the instability in charge-coupling space.


title:
Processes in Resonant Domains of Metal Nanoparticle Aggregates and
  Optical Nonlinearity of Aggregates in Pulsed Laser Fields

abstract:
  The specific optical nonlinearities inherent in aggregates of metal
nanoparticles under pico- and nanosecond pulsed laser irradiation are studied
in nanoparticle aggregates formed in silver hydrosols. The results of
experimental studies of the correlation between the degree of aggregation of
silver hydrosols and their nonlinear refraction index at the wavelengths 0.532
and 1.064 microns are discussed. The experiments revealed that nonlinear
refraction index changes its sign at 1.064 microns as the degree of the
hydrosol aggregation grows. The role of various processes occurring in resonant
domains of aggregates and the kinetics of these processes under laser
irradiation resulting in dynamic variation of the polarizability of aggregates
are analyzed. The areas under study included the kinetics of particles
displacement considering dissipative forces, heating of the particles and of
the surrounding medium depending on the wavelength, intensity and duration of
laser pulses. A theory of interaction of laser radiation with an elementary
type domain - two bound silver nanoparticles - was developed to describe the
kinetics of resonant domains photomodification in aggregates. This theory takes
into account thermal, elastic, electrostatic and light induced effects. The
experimental results on laser photomodification of silver particle aggregates
are discussed in the context of our model. These results include photochromic
and nonlinear optical effects, in particular, the nonlinear refraction and
nonlinear absorption.


title: A Ni-based Superconductor: the Heusler Compound ZrNi$_2$Ga

abstract:
  This work reports on the novel Heusler superconductor ZrNi2Ga. Compared to
other nickel-based superconductors with Heusler structure, ZrNi2Ga exhibits a
relatively high superconducting transition temperature of Tc=2.9 K and an upper
critical field of 1.5 T. Electronic structure calculations show that this
relatively high transition temperature is caused by a van Hove singularity,
which leads to an enhanced density of states at the Fermi energy. The van Hove
singularity originates from a higher order valence instability at the L-point
in the electronic structure. The enhanced density of states at the Fermi level
was confirmed by specific heat and susceptibility measurements. Although many
Heusler compounds are ferromagnetic, our measurements of ZrNi2Ga indicate a
paramagnetic state above Tc and could not reveal any traces of magnetic order
down to temperatures of at least 0.35 K. We investigated in detail the
superconducting state with specific heat, magnetization, and resistivity
measurements. The resulting data show the typical behavior of a conventional,
weakly coupled BCS (s-wave) superconductor.


title:
Single crystal growth and characterizations of Cu0.03TaS2
  superconductors

abstract:
  Single crystal of Cu0.03TaS2 with low copper intercalated content was
successfully grown via chemical iodine-vapor transport. The structural
characterization results show that the copper intercalated 2H-Cu0.03TaS2 single
crystal has the same structure of the CdI2-type structure as the parent 2H-TaS2
crystal. Electrical resistivity and magnetization measurements reveal that
2H-Cu0.03TaS2 becomes a superconductor below 4.2 K. Besides, electrical
resistivity and Hall effects results show that a charge density wave transition
occurs at TCDW = 50 K.


title: Canted Magnetization Texture in Ferromagnetic Tunnel Junctions

abstract:
  We study the formation of inhomogeneous magnetization texture in the vicinity
of a tunnel junction between two ferromagnetic wires nominally in the
antiparallel configuration and its influence on the magnetoresistance of such a
device. The texture, dependent on magnetization rigidity and crystalline
anisotropy energy in the ferromagnet, appears upon an increase of ferromagnetic
inter-wire coupling above a critical value and it varies with an external
magnetic field.


title: Integral and Rxte/Asm Observations on Igr J17098-3628

abstract:
  To probe further the possible nature of the unidentified source IGR
J17098-3628, we have carried out a detailed analysis of its long-term time
variability as monitored by RXTE/ASM, and of its hard X-ray properties as
observed by INTEGRAL. INTEGRAL has monitored this sky region over years and
significantly detected IGR J17098-3628 only when the source was in this dubbed
active state. In particular, at $\ge$ 20 keV, IBIS/ISGRI caught an outburst in
March 2005, lasting for $\sim$5 days with detection significance of 73$\sigma$
(20-40 keV) and with the emission at $< $200 keV. The ASM observations reveal
that the soft X-ray lightcurve shows a similar outburst to that detected by
INTEGRAL, however the peak of the soft X-ray lightcurve either lags, or is
preceded by, the hard X-ray ($>$20 keV) outburst by $\sim$2 days. This
resembles the behavior of X-ray novae like XN 1124-683, hence it further
suggests a LMXB nature for IGR J17098-3628. While the quality of the ASM data
prevents us from drawing any definite conclusions, these discoveries are
important clues that, coupled with future observations, will help to resolve
the as yet unknown nature of IGR J17098-3628.


title: Hawking Fluxes, $W_\infty$ Algebra and Anomalies

abstract:
  We complete the analysis started in [arXiv:0804.0198] of the Hawking
radiation calculated by means of anomaly techniques. We concentrate on a static
radially symmetric BH, reduced to two dimensions. We compare the two methods
used to derive the integrated Hawking radiation, based on the trace and
diffeomorphism anomaly, respectively, and show that they can be reduced to the
same basic elements. We then concentrate on higher moments of the Hawking
radiation and on higher spin currents, and show that, similarly to trace
anomalies, also diffeomorphism anomalies are absent from the conservation laws
of higher spin currents. We show that the predictivity of the method is due to
the $W_\infty$ current algebra underlying the effective model that describes
matter around the black hole.


title:
Gradient theory for plasticity via homogenization of discrete
  dislocations

abstract:
  In this paper, we deduce a macroscopic strain gradient theory for plasticity
from a model of discrete dislocations. We restrict our analysis to the case of
a cylindrical symmetry for the crystal in exam, so that the mathematical
formulation will involve a two dimensional variational problem. The
dislocations are introduced as point topological defects of the strain fields,
for which we compute the elastic energy stored outside the so called core
region. We show that the Gamma-limit as the core radius tends to zero and the
number of dislocations tends to infinity of this energy (suitably rescaled),
takes the form $$ E= \int_{\Om} (W(\beta^e) + \f (\Curl \beta^e)) dx, $$ where
$\beta^e$ represents the elastic part of the macroscopic strain, and $\Curl
\beta^e$ represents the geometrically necessary dislocation density. The
plastic energy density $\f$ is defined explicitly through an asymptotic cell
formula, depending only on the elastic tensor and the class of the admissible
Burgers vectors, accounting for the crystalline structure. It turns out to be
positively 1-homogeneous, so that concentration on lines is permitted,
accounting for the presence of pattern formations observed in crystals such as
dislocation walls.


title: Something about Z-penguins I want to tell

abstract:
  We stress that in models with constrained minimal flavor violation large
negative corrections to the flavor-changing Z-penguin amplitudes are excluded
by the precision measurements of the Z -> b anti-b pseudo observables performed
at LEP and SLC. The derived stringent range for the non-standard contribution
to the universal Inami-Lim function C leads to tight two-sided limits for the
branching ratios of all Z-penguin dominated flavor-changing K- and B-decays.


title: Complete minimal surfaces in R3 with a prescribed coordinate function

abstract:
  In this paper we construct complete simply connected minimal surfaces with a
prescribed coordinate function. Moreover, we prove that these surfaces are
dense in the space of all minimal surfaces with this coordinate function (with
the topology of the smooth convergence on compact sets).


title:
First order Mott transition at zero temperature in two dimensions:
  Variational plaquette study

abstract:
  The nature of the metal-insulator Mott transition at zero temperature has
been discussed for a number of years. Whether it occurs through a quantum
critical point or through a first order transition is expected to profoundly
influence the nature of the finite temperature phase diagram. In this paper, we
study the zero temperature Mott transition in the two-dimensional Hubbard model
on the square lattice with the variational cluster approximation. This takes
into account the influence of antiferromagnetic short-range correlations. By
contrast to single-site dynamical mean-field theory, the transition turns out
to be first order even at zero temperature.


title: Reexamining Black-Body Shifts for Hydrogenlike Ions

abstract:
  We investigate black-body induced energy shifts for low-lying levels of
atomic systems, with a special emphasis on transitions used in current and
planned high-precision experiments on atomic hydrogen and ionized helium.
Fine-structure and Lamb-shift induced black-body shifts are found to increase
with the square of the nuclear charge number, whereas black-body shifts due to
virtual transitions decrease with increasing nuclear charge as the fourth power
of the nuclear charge. We also investigate the decay width acquired by the
ground state of atomic hydrogen, due to interaction with black-body photons.
The corresponding width is due to an instability against excitation to higher
excited atomic levels, and due to black-body induced ionization. These effects
limit the lifetime of even the most fundamental, a priori absolutely stable,
"asymptotic" state of atomic theory, namely the ground state of atomic
hydrogen.


title:
A variational model for quasistatic crack growth in nonlinear
  elasticity: some qualitative properties of the solutions

abstract:
  We present the main existence result for quasistatic crack growth in the
model proposed by Dal Maso, Francfort, and Toader, and prove some qualitative
properties of the solutions.


title: Extreme multiplex spectroscopy at wide-field 4-m telescopes

abstract:
  We describe the design and science case for a spectrograph for the prime
focus of classical 4-m wide-field telescopes that can deliver at least 4000 MOS
slits over a 1 degree field. This extreme multiplex capability means that 25000
galaxy redshifts can be measured in a single night, opening up the
possibilities for large galaxy redshift surveys out to z~0.7 and beyond for the
purpose of measuring the Baryon Acoustic Oscillation (BAO) scale and for many
other science goals. The design features four cloned spectrographs and exploits
the exclusive possibility of tiling the focal plane of wide-field 4-m
telescopes with CCDs for multi-object spectroscopic purposes. In ~200 night
projects, such spectrographs have the potential to make galaxy redshift surveys
of ~6 million galaxies over a wide redshift range and thus may provide a
low-cost alternative to other survey routes such as WFMOS and SKA. Two of these
extreme multiplex spectrographs are currently being designed for the AAT
(NG1dF) and Calar Alto (XMS) 4-m class telescopes. NG2dF, a larger version for
the AAT 2 degree field, would have 12 clones and at least 12000 slits. The
clones use a transparent design including a grism in which all optics are
smaller than the clone square subfield so that the clones can be tightly packed
with little gaps between the contiguous fields. Only low cost glasses are used;
the variations in chromatic aberrations between bands are compensated by
changing one or two of the lenses adjacent to the grism. The total weight and
length is smaller with a few clones than a unique spectrograph which makes it
feasible to place the spectrograph at the prime focus.


title: Strong Spectral Gaps for Compact Quotients of Products of $\PSL(2,\bbR)$

abstract:
  The existence of a strong spectral gap for quotients $\Gamma\bs G$ of
noncompact connected semisimple Lie groups is crucial in many applications. For
congruence lattices there are uniform and very good bounds for the spectral gap
coming from the known bounds towards the Ramanujan-Selberg Conjectures. If $G$
has no compact factors then for general lattices a strong spectral gap can
still be established, however, there is no uniformity and no effective bounds
are known. This note is concerned with the strong spectral gap for an
irreducible co-compact lattice $\Gamma$ in $G=\PSL(2,\bbR)^d$ for $d\geq 2$
which is the simplest and most basic case where the congruence subgroup
property is not known. The method used here gives effective bounds for the
spectral gap in this setting.


title: Collisional energy transfer in two-component plasmas

abstract:
  The friction in plasmas consisting of two species with different temperatures
is discussed together with the consequent energy transfer. It is shown that the
friction between the two species has no effect on the ion acoustic mode in a
quasi-neutral plasma. Using the Poisson equation instead of the
quasi-neutrality reveals the possibility for an instability driven by the
collisional energy transfer. However, the different starting temperatures of
the two species imply an evolving equilibrium. It is shown that the relaxation
time of the equilibrium electron-ion plasma is, in fact, always shorter than
the growth rate time, and the instability can thus never effectively take
place. The results obtained here should contribute to the definite
clarification of some contradictory results obtained in the past.


title:
Driving Weiss oscillations to Zero Resistance States by Microwave
  Radiation

abstract:
  In this work we present a theoretical model to study the effect of microwave
radiation on Weiss oscillations. In our proposal Weiss oscillations, produced
by an spatial periodic potential, are modulated by microwave radiation due to
an interference effect between both, space and time-dependent, potentials. The
final magnetoresistance depends mainly on the spatial period of the spatial
potential and the frequency of radiation. Depending on the values of these
parameters, we predict that Weiss oscillations can reach zero resistance
states. On the other hand, these dissipationless transport states, created just
by radiation, can be destroyed by the additional presence of a periodic
space-dependent potential. Then by tuning the spatial period or the radiation
frequency, the magnetoresistance can be strongly modified.


title: Direct X-ray Spectral Deprojection of Galaxy Clusters

abstract:
  Temperature, density and abundance profiles of the hot intracluster medium
(ICM) are important diagnostics of the complex interactions of gravitational
and feedback processes in the cores of galaxy clusters. Deprojection of X-ray
data by methods such as projct, which are model dependent, can produce large
and unphysical oscillating temperature profiles. Here we validate a
deprojection routine, Direct Spectral Deprojection (DSDeproj; Sanders & Fabian
2007), showing that it solves some of the issues inherent to model-dependent
deprojection routines. DSDeproj is a model-independent approach, assuming only
spherical symmetry, which subtracts projected spectra from each successive
annulus to produce a set of deprojected spectra.


title: Dilution effect in correlated electron system with orbital degeneracy

abstract:
  Theory of dilution effect in orbital ordered system is presented. The $e_g$
orbital model without spin degree of freedom and the spin-orbital coupled model
in a three-dimensional simple-cubic lattice are analyzed by the Monte-Carlo
simulation and the cluster expansion method. In the $e_g$ orbital model without
spin degree of freedom, reduction of the orbital ordering temperature due to
dilution is steeper than that in the dilute magnet. This is attributed to a
modification of the orbital wave-function around vacant sites. In the
spin-orbital coupled model, it is found that magnetic structure is changed from
the A-type antiferromagnetic order into the ferromagnetic one. Orbital
dependent exchange interaction and a sign change of this interaction around
vacant sites bring about this novel phenomena. Present results explain the
recent experiments in transition-metal compounds with orbital dilution.


title: Tests of multimode quantum non-locality with homodyne measurements

abstract:
  We investigate the violation of local realism in Bell tests involving
homodyne measurements performed on multimode continuous-variable states. By
binning the measurement outcomes in an appropriate way, we prove that the
Mermin-Klyshko inequality can be violated by an amount that grows exponentially
with the number of modes. Furthermore, the maximum violation allowed by quantum
mechanics can be attained for any number of modes, albeit requiring a quantum
state that is rather unrealistic. Interestingly, this exponential increase of
the violation holds true even for simpler states, such as multipartite GHZ
states. The resulting benefit of using more modes is shown to be significant in
practical multipartite Bell tests by analyzing the increase of the robustness
to noise with the number of modes. In view of the high efficiency achievable
with homodyne detection, our results thus open a possible way to feasible
loophole-free Bell tests that are robust to experimental imperfections. We
provide an explicit example of a three-mode state (a superposition of coherent
states) which results in a significantly high violation of the Mermin-Klyshko
inequality (around 10%) with homodyne measurements.


title: Gluonic Pole Matrix Elements in Spectator Models

abstract:
  We investigate the gluonic pole matrix element contributing to the first
$p_T$ moment of the distribution and fragmentation functions in a spectator
model. By performing a spectral analysis, we find that for a large class of
spectator models, the contribution of gluonic pole matrix elements is non-zero
for the distribution correlators, whereas in fragmentation correlators they
vanish. This outcome is important in the study of universality for
fragmentation functions.


title: Molecular Emission Line Formation in Prestellar Cores

abstract:
  We investigate general aspects of molecular line formation under conditions
which are typical of prestellar cores. Focusing on simple linear molecules, we
study formation of their rotational lines by radiative transfer simulations. We
present a thermalization diagram to show the effects of collisions and
radiation on the level excitation. We construct a detailed scheme (contribution
chart) to illustrate the formation of emission line profiles. This chart can be
used as an efficient tool to identify which parts of the cloud contribute to a
specific line profile. We show how molecular line characteristics for uniform
model clouds depend on hydrogen density, molecular column density, and kinetic
temperature. The results are presented in a 2D plane to illustrate cooperative
effects of the physical factors. We also use a core model with a non-uniform
density distribution and chemical stratification to study the effects of cloud
contraction and rotation on spectral line maps. We discuss the main issues that
should be taken into account when dealing with interpretation and simulation of
observed molecular lines.


title: Liouville Theory and Elliptic Genera

abstract:
  The structure and modular properties of N=4 superconformal characters are
reviewed and exploited, in an attempt to construct elliptic genera-like
functions by decompactifying K3. The construction is tested against expressions
obtained in the context of strings propagating in background ALE spaces of type
A(n-1), using the underlying superconformal theory, i.e the tensor product of
N=2 minimal with N=2 Liouville theory.


title:
The precursor state to superconductivity in CeIrIn${_5}$: Unusual
  scaling of magnetotransport

abstract:
  We present an analysis of the normal-state Hall effect and magnetoresistance
in the heavy fermion superconductor CeIrIn${_5}$. It is demonstrated that the
modified Kohler's scaling--which relates the magnetoresistance to the Hall
angle--breaks down prior to the onset of superconductivity due to the presence
of a precursor state to superconductivity in this system. A model-independent,
single-parameter scaling of the Hall angle governed solely by this precursor
state is observed. Neither the Hall coefficient nor the resistivity exhibit
this scaling implying that this precursor state preferentially influences the
Hall channel.


title:
Synchrotron radiation from a charge moving along a helix around a
  dielectric cylinder

abstract:
  In this paper we investigate the radiation emitted by a charged particle
moving along a helical orbit around a dielectric cylinder immersed into a
homogeneous medium. Formulae are derived for the electromagnetic potentials,
electric and magnetic fields, and for the spectral-angular distribution of the
radiation in the exterior medium. It is shown that under the Cherenkov
condition for dielectric permittivity of the cylinder and the velocity of the
particle image on the cylinder surface, strong narrow peaks appear in the
angular distribution for the number of quanta radiated on a given harmonic. At
these peaks the radiated energy exceeds the corresponding quantity for a
homogeneous medium by several dozens of times. Simple analytic estimates are
given for the heights and widths of these peaks. The results of numerical
calculations for the angular distribution of the radiated quanta are presented
and they are compared with the corresponding quantities for the radiation from
a charge moving along a helical trajectory inside a dielectric cylinder.