title:
On the validity and breakdown of the Onsager symmetry in mesoscopic
  conductors interacting with environments

abstract:
  We investigate magnetic-field asymmetries in the linear transport of a
mesoscopic conductor interacting with its environment. Interestingly, we find
that the interaction between the two systems causes an asymmetry only when the
environment is out of equilibrium. We elucidate our general result with the
help of a quantum dot capacitively coupled to a quantum Hall conductor and
discuss the asymmetry dependence on the environment bias and induced dephasing.


title:
Station-Keeping Requirements for Constellations of Free-Flying
  Collectors Used for Astronomical Imaging in Space

abstract:
  The accuracy requirements on station-keeping for constellations of
free-flying collectors coupled as (future) imaging arrays in space for
astrophysics applications are examined. The basic imaging element of these
arrays is the two-element interferometer. Accurate knowledge of two quantities
is required: the \textit{projected baseline length}, which is the distance
between the two interferometer elements projected on the plane tranverse to the
line of sight to the target; and the \textit{optical path difference}, which is
the difference in the distances from that transverse plane to the beam
combiner. ``Rules-of-thumb'' are determined for the typical accuracy required
on these parameters. The requirement on the projected baseline length is a
\textit{knowledge} requirement and depends on the angular size of the targets
of interest; it is generally at a level of half a meter for typical stellar
targets, decreasing to perhaps a few centimeters only for the widest attainable
fields of view. The requirement on the optical path difference is a
\textit{control} requirement and is much tighter, depending on the bandwidth of
the signal; it is at a level of half a wavelength for narrow (few %) signal
bands, decreasing to $\approx 0.2 \lambda$ for the broadest bandwidths expected
to be useful. Translation of these requirements into engineering requirements
on station-keeping accuracy depends on the specific details of the collector
constellation geometry. Several examples are provided to guide future
application of the criteria presented here. Some implications for the design of
such collector constellations and for the methods used to transform the
information acquired into images are discussed.


title: BFKL Effects in Azimuthal Angle Correlations of Forward Jets

abstract:
  The azimuthal angle correlation of Mueller-Navelet jets at hadron colliders
is studied in the NLO BFKL formalism. We highlight the need of collinear
improvements in the kernel to obtain good convergence properties and we obtain
better fits for the Tevatron data than at LO accuracy. We also estimate these
correlations for larger rapidity differences available at the LHC.


title: LAMN property for hidden processes: the case of integrated diffusions

abstract:
  In this paper we prove the Local Asymptotic Mixed Normality (LAMN) property
for the statistical model given by the observation of local means of a
diffusion process $X$. Our data are given by $ \int_0^1 X_{\frac{s+i}{n}} \dd
\mu (s)$ for $i=0,...,n-1$ and the unknown parameter appears in the diffusion
coefficient of the process $X$ only. Although the data are nor Markovian
neither Gaussian we can write down, with help of Malliavin calculus, an
explicit expression for the log-likelihood of the model, and then study the
asymptotic expansion. We actually find that the asymptotic information of this
model is the same one as for a usual discrete sampling of $X$.


title: Yang-Mills Connections On Orientable and Nonorientable Surfaces

abstract:
  In math.SG/0605587, we studied Yang-Mills functional on the space of
connections on a principal G_R-bundle over a closed, connected, nonorientable
surface, where G_R is any compact connected Lie group. In this sequel, we
generalize the discussion in "The Yang-Mills equations over Riemann surfaces"
by Atiyah and Bott, and math.SG/0605587. We obtain explicit descriptions (as
representation varieties) of Morse strata of Yang-Mills functional on
orientable and nonorientable surfaces for non-unitary classical groups SO(n)
and Sp(n). It turns out to be quite different from the unitary case. we use
Laumon and Rapoport's method in "The Langlands lemma and the Betti numbers of
stacks of G-bundles on a curve" to invert the Atiyah-Bott recursion relation,
and write down explicit formulas of rational equivariant Poincar\'{e} series of
the semistable stratum of the space of holomorphic structures on a principal
$SO(n,\bC)$-bundle or a principal $Sp(n,\bC)$-bundle.


title: On the affineness of Deligne-Lusztig varieties

abstract:
  We prove that the Deligne-Lusztig variety associated to minimal length
elements in any $\d$-conjugacy class of the Weyl group is affine, which was
conjectured by Orlik and Rapoport in \cite{OR}.


title: Near UV properties of Early-Type Galaxies at z~1

abstract:
  We have used spectral fits to SSP-based atmosphere models to derive an
estimate of the average stellar age for an almost complete sample of 15
Early-Type Galaxies (ETG) at 0.88<z<1.3. The results are in only partial
agreement with the age estimates previously obtained for the same objects from
an analysis of the M/L_B ratio, derived from the Fundamental Plane (FP)
parameters. In particular spectral fits seem to underestimate the age of the
most luminous ETG, and therefore do not reproduce the downsizing effect, which
is clear for the FP ages. We also analyse the relationship between the
spectral-fit ages and various near-UV spectral indices.


title: Photons and Dileptons at LHC

abstract:
  We discuss real and virtual photon sources in heavy ion collisions and
present results for dilepton yields in Pb+Pb collisions at the LHC at
intermediate and large transverse momentum p_T.


title: Investigation of a0-f0 mixing

abstract:
  We investigate the isospin-violating mixing of the light scalar mesons
a0(980) and f0(980) within the unitarized chiral approach. Isospin-violating
effects are considered to leading order in the quark mass differences and
electromagnetism. In this approach both mesons are generated through
meson-meson dynamics. Our results provide a description of the mixing
phenomenon within a framework consistent with chiral symmetry and unitarity,
where these resonances are not predominantly q q-bar states. Amongst the
possible experimental signals, we discuss observable consequences for the
reaction J/Psi -> phi pi0 eta in detail. In particular we demonstrate that the
effect of a0-f0 mixing is by far the most important isospin-breaking effect in
the resonance region and can indeed be extracted from experiment.


title: Review of Bu leptonic decays

abstract:
  This paper reviews the status of searches and measurements of Bu leptonic
decays, concentrating on the most recent results obtained at B-factories. We
will describe studies of decays of the type B+ -> ell+ nu and B+ -> ell+ nu
gamma.


title: Magnetar-energized supernova explosions and GRB-jets

abstract:
  In this paper we report on the early evolution of core-collapse supernova
explosion following the birth of a magnetar with the dipolar magnetic field of
B=10^{15}G and the rotational period of 2ms, which was studied by means of
axisymmetric general relativistic MHD simulations. The numerical models exhibit
highly collimated magnetically-driven jets very early on. The jets are
super-Alfvenic but remain sub-fast until the end of the simulations (t=0.2s).
The power released in the jets is about 3x10^{50}erg/s which implies the
spin-down time of ~37s. The total rotational energy of the magnetar,
E~10^{52}erg, is sufficient to drive hypernova but it is not clear as to how
large a fraction of this energy can be transfered to the stellar envelope.
Given the observed propagation speed of the jets, v_p~0.17c, they are expected
to traverse the progenitor in few seconds and after this most of the released
rotational energy would be simply carried away by these jets into the
surrounding space. Our results provide the first more or less self-consistent
numerical model of a central engine capable of producing, in the supernova
setting and on a long-term basis, collimated jets with sufficient power to
explain long duration GRBs and their afterglows. Although the flow speed of our
jets is relatively low, v_j~0.5c$, the cooling of proto-neutron star will
eventually result in much higher magnetization of its magnetospheres and
ultra-relativistic asymptotic speeds of the jets. Given the relatively long
cooling time-scale we still expect the jets to be only weakly relativistic by
the time of break out. This leads to a model of GRB jets with systematic
longitudinal variation of Lorentz factor which may have specific observational
signatures both in the prompt and the afterglow emission.


title: Long term ordering kinetics of the two dimensional q-state Potts model

abstract:
  We studied the non-equilibrium dynamics of the q-state Potts model in the
square lattice, after a quench to sub-critical temperatures. By means of a
continuous time Monte Carlo algorithm (non-conserved order parameter dynamics)
we analyzed the long term behavior of the energy and relaxation time for a wide
range of quench temperatures and system sizes. For q>4 we found the existence
of different dynamical regimes, according to quench temperature range. At low
(but finite) temperatures and very long times the Lifshitz-Allen-Cahn domain
growth behavior is interrupted with finite probability when the system stuck in
highly symmetric non-equilibrium metastable states, which induce activation in
the domain growth, in agreement with early predictions of Lifshitz [JETP 42,
1354 (1962)]. Moreover, if the temperature is very low, the system always gets
stuck at short times in a highly disordered metastable states with finite life
time, which have been recently identified as glassy states. The finite size
scaling properties of the different relaxation times involved, as well as their
temperature dependency are analyzed in detail.


title:
Increasing entanglement through engineered disorder in the random Ising
  chain

abstract:
  The ground state entanglement entropy between block of sites in the random
Ising chain is studied by means of the Von Neumann entropy. We show that in
presence of strong correlations between the disordered couplings and local
magnetic fields the entanglement increases and becomes larger than in the
ordered case. The different behavior with respect to the uncorrelated
disordered model is due to the drastic change of the ground state properties.
The same result holds also for the random 3-state quantum Potts model.


title: Quantum Attractor Flows

abstract:
  Motivated by the interpretation of the Ooguri-Strominger-Vafa conjecture as a
holographic correspondence in the mini-superspace approximation, we study the
radial quantization of stationary, spherically symmetric black holes in four
dimensions. A key ingredient is the classical equivalence between the radial
evolution equation and geodesic motion of a fiducial particle on the moduli
space M^*_3 of the three-dimensional theory after reduction along the time
direction. In the case of N=2 supergravity, M^*_3 is a para-quaternionic-Kahler
manifold; in this case, we show that BPS black holes correspond to a particular
class of geodesics which lift holomorphically to the twistor space Z of M^*_3,
and identify Z as the BPS phase space. We give a natural quantization of the
BPS phase space in terms of the sheaf cohomology of Z, and compute the exact
wave function of a BPS black hole with fixed electric and magnetic charges in
this framework. We comment on the relation to the topological string amplitude,
extensions to N>2 supergravity theories, and applications to automorphic black
hole partition functions.


title: Quantum Imaging

abstract:
  One of the most surprising consequences of quantum mechanics is the
entanglement of two or more distant particles. Although questions regarding
fundamental issues of quantum theory still exist, quantum entanglement has
started to play important roles in practical engineering applications. Quantum
imaging is one of these exciting areas. Quantum imaging has demonstrated two
peculiar features: (1) reproducing "ghost" images in a "nonlocal" manner, and
(2) enhancing the spatial resolution of imaging beyond the diffraction limit.
In this article, we start with the review of classical imaging to establish the
basic concepts and formalisms of imaging. We then analyze two-photon imaging
with particular emphasis on the physics of spatial resolution enhancement and
the "ghost" imaging phenomenon.


title: Star formation in young star cluster NGC 1893

abstract:
  We present a comprehensive multi-wavelength study of the star-forming region
NGC 1893 to explore the effects of massive stars on low-mass star formation.
Using near-infrared colours, slitless spectroscopy and narrow-band $H\alpha$
photometry in the cluster region we have identified candidate young stellar
objects (YSOs) distributed in a pattern from the cluster to one of the nearby
nebulae Sim 129. The $V, (V-I)$ colour-magnitude diagram of the YSOs indicates
that majority of these objects have ages between 1 to 5 Myr. The spread in the
ages of the YSOs may indicate a non-coeval star formation in the cluster. The
slope of the KLF for the cluster is estimated to be $0.34\pm0.07$, which agrees
well with the average value ($\sim 0.4$) reported for young clusters. For the
entire observed mass range $0.6 < M/M_\odot \le 17.7$ the value of the slope of
the initial mass function, $`\Gamma$', comes out to be $-1.27\pm0.08$, which is
in agreement with the Salpeter value of -1.35 in the solar neighborhood.
However, the value of $`\Gamma$' for PMS phase stars (mass range $0.6 <
M/M_\odot \le 2.0$) is found to be $-0.88\pm0.09$ which is shallower than the
value ($-1.71\pm0.20$) obtained for MS stars having mass range $2.5 < M/M_\odot
\le 17.7$ indicating a break in the slope of the mass function at $\sim 2
M_\odot$. Estimated $`\Gamma$' values indicate an effect of mass segregation
for main-sequence stars, in the sense that massive stars are preferentially
located towards the cluster center. The estimated dynamical evolution time is
found to be greater than the age of the cluster, therefore the observed mass
segregation in the cluster may be the imprint of the star formation process.
There is evidence for triggered star formation in the region, which seems to
govern initial morphology of the cluster.


title: The Sagnac effect in superfluids

abstract:
  We comment on the interpretation of absolute rotation measurements with
superfluids, which involve the Sagnac effect. This effect, first observed in
rotating optical interferometers, has now been seen in a host of different
physical systems, ranging from atomic clocks to electrons, neutrons, atomic
beams, ... We show that the time-honored explanation of this effect based on
general relativity provides a common explanation for all these systems,
including superfluids, in contradistinction with the views expressed in a
recent review article.


title: Maximum Likelihood Estimator for Hidden Markov Models in continuous time

abstract:
  The paper studies large sample asymptotic properties of the Maximum
Likelihood Estimator (MLE) for the parameter of a continuous time Markov chain,
observed in white noise. Using the method of weak convergence of likelihoods
due to I.Ibragimov and R.Khasminskii, consistency, asymptotic normality and
convergence of moments are established for MLE under certain strong ergodicity
conditions of the chain.


title: Solitary wave dynamics in time-dependent potentials

abstract:
  We rigorously study the long time dynamics of solitary wave solutions of the
nonlinear Schr\"odinger equation in {\it time-dependent} external potentials.
To set the stage, we first establish the well-posedness of the Cauchy problem
for a generalized nonautonomous nonlinear Schr\"odinger equation. We then show
that in the {\it space-adiabatic} regime where the external potential varies
slowly in space compared to the size of the soliton, the dynamics of the center
of the soliton is described by Hamilton's equations, plus terms due to
radiation damping. We finally remark on two physical applications of our
analysis. The first is adiabatic transportation of solitons, and the second is
Mathieu instability of trapped solitons due to time-periodic perturbations.


title: Quantum gravity and the Coulomb potential

abstract:
  We apply a singularity resolution technique utilized in loop quantum gravity
to the polymer representation of quantum mechanics on R with the singular
-1/|x| potential. On an equispaced lattice, the resulting eigenvalue problem is
identical to a finite difference approximation of the Schrodinger equation. We
find numerically that the antisymmetric sector has an energy spectrum that
converges to the usual Coulomb spectrum as the lattice spacing is reduced. For
the symmetric sector, in contrast, the effect of the lattice spacing is similar
to that of a continuum self-adjointness boundary condition at x=0, and its
effect on the ground state is significant even if the spacing is much below the
Bohr radius. Boundary conditions at the singularity thus have a significant
effect on the polymer quantization spectrum even after the singularity has been
regularized.


title: QCD and spin effects in black hole airshowers

abstract:
  In models with large extra dimensions, black holes may be produced in
high-energy particle collisions. We revisit the physics of black hole formation
in extensive airshowers from ultrahigh-energy cosmic rays, focusing on
collisional QCD and black hole emissivity effects. New results for rotating
black holes are presented. Monte Carlo simulations show that QCD effects and
black hole spin produce no observable signatures in airshowers. These results
further confirm that the main characteristics of black hole-induced airshowers
do not depend on the fine details of micro black hole models.


title: Global QCD Analysis and Collider Phenomenology--CTEQ

abstract:
  An overview is given of recent progress on a variety of fronts in the global
QCD analysis of the parton structure of the nucleon and its implication for
collider phenomenology, carried out by various subgroups of the CTEQ
collaboration.


title:
Transverse momentum broadening of vector bosons in heavy ion collisions
  at the LHC

abstract:
  We calculate in perturbative QCD the transverse momentum broadening of vector
bosons in heavy ion collisions at the Large Hadron Collider (LHC). We predict
transverse momentum broadening of $W/Z$ bosons constructed from their leptonic
decay channels, which should be a clean probe of initial-state medium effect.
We also predict the upper limit of transverse momentum broadening of J/$\psi$
and $\Upsilon$ production as a function of N$_{\rm part}$ at the LHC energy.


title: Magnetic phases in the correlated Kondo-lattice model

abstract:
  We study magnetic ordering of an extended Kondo-lattice model including an
additional on-site Coulomb interaction between the itinerant states. The model
is solved in the dynamical mean-field theory using Wilson's numerical
renormalization group approach as impurity solver. For a bipartite lattice we
find at half filling the expected antiferromagnetic phase. Upon doping this
phase is gradually suppressed and hints towards phase separation are observed.
For large doping the model exhibits ferromagnetism, the appearance of which can
at first sight be explained by Rudermann-Kittel-Kasuya-Yosida interaction.
However, for large values of the Kondo coupling $J$ significant differences to
a simple Rudermann-Kittel-Kasuya-Yosida picture can be found. We furthermore
observe signs of quantum critical points for antiferromagnetic Kondo coupling
between the local spins and band states.


title:
Headgroup dimerization in methanethiol monolayers on the Au(111)
  surface: a density functional theory study

abstract:
  A long-standing controversy related to the dimer pattern formed by S atoms in
methanethiol ($CH_{3}SH$) on the Au(111) surface has been resolved using
density functional theory. For the first time, dimerization of methanethiol
adsorbates on the Au(111) surface is established by computational modeling. For
methylthiolate ($CH_{3}S$), it is shown that the S atoms do not dimerize at
high coverage but reveal a dimer pattern at intermediate coverage. Molecular
dynamics simulation at high coverage demonstrates that the observed dialkyl
disulfide species are formed during the desorption process, and thus are not
attached to the surface.


title: Accelerating Cosmologies with an Anisotropic Equation of State

abstract:
  If the dark energy equation of state is anisotropic, the expansion rate of
the universe becomes direction-dependent at late times. We show that such
models are not only cosmologically viable but that they could explain some of
the observed anomalies in the CMB, and shed some light into the coincidence
problem. The possible anisotropy can then be constrained by studying its
effects on the luminosity distance-redshift relation inferred from several
observations. A vector field action for dark energy is also presented as an
example of such possibility.


title:
Spin-lattice instability to a fractional magnetization state in the
  spinel HgCr2O4

abstract:
  Magnetic systems are fertile ground for the emergence of exotic states when
the magnetic interactions cannot be satisfied simultaneously due to the
topology of the lattice - a situation known as geometrical frustration.
Spinels, AB2O4, can realize the most highly frustrated network of
corner-sharing tetrahedra. Several novel states have been discovered in
spinels, such as composite spin clusters and novel charge-ordered states. Here
we use neutron and synchrotron X-ray scattering to characterize the fractional
magnetization state of HgCr2O4 under an external magnetic field, H. When the
field is applied in its Neel ground state, a phase transition occurs at H ~ 10
Tesla at which each tetrahedron changes from a canted Neel state to a
fractional spin state with the total spin, Stet, of S/2 and the lattice
undergoes orthorhombic to cubic symmetry change. Our results provide the
microscopic one-to-one correspondence between the spin state and the lattice
distortion.


title: On Fox quotients of arbitrary group algebras

abstract:
  For a group $G$, N-series $\cal G$ of $G$ and commutative ring $R$ let
$I^n_{R,\cal G}(G)$, $n\ge 0$, denote the filtration of the group algebra
$R(G)$ induced by $\cal G$, and $I_R(G)$ its augmentation ideal. For subgroups
$H$ of $G$, left ideals $J$ of $R(H)$ and right $H$-submodules $M$ of $I_Z(G)$
the quotients $I_R(G)J/MJ$ are studied by homological methods, notably for $M=
I_Z(G)I_Z(H)$, $I_Z(H)I_Z(G) + I_Z([H,G])Z(G)$ and $Z(G)I_Z(N) +I^n_{Z,\cal
G}(G)$ with $N \lhd G$ where the group $I_R(G)J/MJ$ is completely determined
for $n=2$. The groups $I^{n-1}_{Z,\cal G}(G)I_Z(H)/I^n_{Z,\cal G}(G)I_Z(H)$ are
studied and explicitly computed for $n\le 3$ in terms of enveloping rings of
certain graded Lie rings and of torsion products of abelian groups.


title: Directed Feedback Vertex Set is Fixed-Parameter Tractable

abstract:
  We resolve positively a long standing open question regarding the
fixed-parameter tractability of the parameterized Directed Feedback Vertex Set
problem. In particular, we propose an algorithm which solves this problem in
$O(8^kk!*poly(n))$.


title:
What SWIFT has taught us about X-ray flashes and long-duration gamma-ray
  bursts

abstract:
  Recent data gathered and triggered by the SWIFT satellite have greatly
improved our knowledge of long-duration gamma ray bursts (GRBs) and X-ray
flashes (XRFs). This is particularly the case for the X-ray data at all times,
and for UV and optical data at very early times. I show that the optical and
X-ray observations are in excellent agreement with the predictions of the
"cannonball" model of GRBs and XRFs. Elementary physics and just two mechanisms
underlie these predictions: inverse Compton scattering and synchrotron
radiation, generally dominant at early and late times, respectively. I put this
result in its proper context and dedicate the paper to those who planed, built
and operate SWIFT, a true flying jewel.


title:
A statistical theory for the measurement and estimation of Rayleigh
  fading channel

abstract:
  In this paper, we propose a statistical theory on measurement and estimation
of Rayleigh fading channels in wireless communications and provide complete
solutions to the fundamental problems: What is the optimum estimator for the
statistical parameters associated with the Rayleigh fading channel, and how
many measurements are sufficient to estimate these parameters with the
prescribed margin of error and confidence level? Our proposed statistical
theory suggests that two testing signals of different strength be used. The
maximum likelihood (ML) estimator is obtained for estimation of the statistical
parameters of the Rayleigh fading channel that is both sufficient and complete
statistic. Moreover, the ML estimator is the minimum variance (MV) estimator
that in fact achieves the Cramer-Rao lower bound.


title: A Generalized Sampling Theorem for Frequency Localized Signals

abstract:
  A generalized sampling theorem for frequency localized signals is presented.
The generalization in the proposed model of sampling is twofold: (1) It applies
to various prefilters effecting a "soft" bandlimitation, (2) an approximate
reconstruction from sample values rather than a perfect one is obtained (though
the former might be "practically perfect" in many cases). For an arbitrary
finite-energy signal the frequency localization is performed by a prefilter
realizing a crosscorrelation with a function of prescribed properties. The
range of the filter, the so-called localization space, is described in some
detail. Regular sampling is applied and a reconstruction formula is given. For
the reconstruction error a general error estimate is derived and connections
between a critical sampling interval and notions of "soft bandwidth" for the
prefilter are indicated. Examples based on the sinc-function, Gaussian
functions and B-splines are discussed.


title: The relative second Fox and third dimension subgroup of arbitrary groups

abstract:
  Let $I_R(G)$ denote the augmentation ideal of the group algebra $R(G)$ of a
group $G$ with coefficients in a commutative ring $R$. We give a complete
description of the third relative dimension subgroup
$G\cap(1+I_R(K)I_R(G)+I^3_R(G))$ and the second relative Fox subgroup
$G\cap(1+I_R(K)I_R(H)+I^2_R(G)I_R(H))$ for any subgroups $K$ and $H$ of $G$.


title:
Monitoring the Variable Interstellar Absorption toward HD 219188 with
  HST/STIS

abstract:
  We discuss the results of continued spectroscopic monitoring of the variable
intermediate-velocity (IV) absorption at v = -38 km/s toward HD 219188. After
reaching maxima in mid-2000, the column densities of both Na I and Ca II in
that IV component declined by factors >= 2 by the end of 2006. Comparisons
between HST/STIS echelle spectra obtained in 2001, 2003, and 2004 and HST/GHRS
echelle spectra obtained in 1994--1995 indicate the following: (1) The
absorption from the dominant species S II, O I, Si II, and Fe II is roughly
constant in all four sets of spectra -- suggesting that the total N(H) and the
(mild) depletions have not changed significantly over a period of nearly ten
years. (2) The column densities of the trace species C I (both ground and
excited fine-structure states) and of the excited state C II* all increased by
factors of 2--5 between 1995 and 2001 -- implying increases in the hydrogen
density n_H (from about 20 cm^{-3} to about 45 cm^{-3}) and in the electron
density n_e (by a factor >= 3) over that 6-year period. (3) The column
densities of C I and C II* -- and the corresponding inferred n_H and n_e --
then decreased slightly between 2001 and 2004. (4) The changes in C I and C II*
are very similar to those seen for Na I and Ca II. The relatively low total
N(H) and the modest n_H suggest that the -38 km/s cloud toward HD 219188 is not
a very dense knot or filament. Partial ionization of hydrogen appears to be
responsible for the enhanced abundances of Na I, C I, Ca II, and C II*. In this
case, the variations in those species appear to reflect differences in density
and ionization [and not N(H)] over scales of tens of AU.


title:
The clustering of merging star-forming haloes: dust emission as high
  frequency arcminute CMB foreground

abstract:
  Future observations of CMB anisotropies will be able to probe high multipole
regions of the angular power spectrum, corresponding to a resolution of a few
arcminutes. Dust emission from merging haloes is one of the foregrounds that
will affect such very small scales. We estimate the contribution to CMB angular
fluctuations from objects that are bright in the sub-millimeter band due to
intense star formation bursts following merging episodes. We base our approach
on the Lacey-Cole merger model and on the Kennicutt relation which connects the
star formation rate in galaxies with their infrared luminosity. We set the free
parameters of the model in order to not exceed the SCUBA source counts, the
Madau plot of star formation rate in the universe and COBE/FIRAS data on the
intensity of the sub-millimeter cosmic background radiation. We show that the
angular power spectrum arising from the distribution of such star-forming
haloes will be one of the most significant foregrounds in the high frequency
channels of future CMB experiments, such as PLANCK, ACT and SPT. The
correlation term, due to the clustering of multiple haloes at redshift z~2-6,
is dominant in the broad range of angular scales 200<l<3000. Poisson
fluctuations due to bright sub-millimeter sources are more important at higher
l, but since they are generated from the bright sources, such contribution
could be strongly reduced if bright sources are excised from the sky maps. The
contribution of the correlation term to the angular power spectrum depends
strongly on the redshift evolution of the escape fraction of UV photons and the
resulting temperature of the dust. The measurement of this signal will
therefore give important information about galaxies in the early stage of their
evolution.


title: Transport through single-level quantum dot in a magnetic field

abstract:
  We study the effect of an external magnetic field on the transport properties
of a quantum dot using a recently developed extension of the functional
renormalization group approach to non-equilibrium situations. We discuss in
particular the interplay and competition of the different energy scales of the
dot and the magnetic field on the stationary non-equilibrium current and
conductance. As rather interesting behavior we find a switching behavior of the
magnetic field for intermediate correlations and bias voltage.


title:
Neutrino Mass Hierarchy and Stepwise Spectral Swapping of Supernova
  Neutrino Flavors

abstract:
  We examine a phenomenon recently predicted by numerical simulations of
supernova neutrino flavor evolution: the swapping of supernova $\nu_e$ and
$\nu_{\mu,\tau}$ energy spectra below (above) energy $\EC$ for the normal
(inverted) neutrino mass hierarchy. We present the results of large-scale
numerical calculations which show that in the normal neutrino mass hierarchy
case, $\EC$ decreases as the assumed $\nu_e\rightleftharpoons\nu_{\mu,\tau}$
effective $2\times 2$ vacuum mixing angle ($\simeq \theta_{1 3}$) is decreased.
However, these calculations also indicate that $\EC$ is essentially independent
of the vacuum mixing angle in the inverted neutrino mass hierarchy case. With a
good neutrino signal from a future Galactic supernova, the above results could
be used to determine the neutrino mass hierarchy even if $\theta_{13}$ is too
small to be detected in terrestrial neutrino oscillation experiments.


title: On the second cohomology of semidirect products

abstract:
  Let $G$ be a group which is the semidirect product of a normal subgroup $N$
and a subgroup $T$, and let $M$ be a $G$-module with not necessarily trivial
$G$-action. Then we embed the simultaneous restriction map
$res=(res^G_N,res^G_T)^t : H^2(G,M) \to H^2(N,M)^T \times H^2(T,M)$ into a
natural five term exact sequence consisting of one and two-dimensional
cohomology groups of the factors $N$ and $T$. The elements of $H^2(G,M)$ are
represented in terms of group extensions of $G$ by $M$ constructed from
extensions of $N$ and $T$.


title: Constraints on oscillating dark energy models

abstract:
  The oscillating scenario of route to Lambda was recently proposed by us
arXiv:0704.1651 as an alternative to a cosmological constant in a explanation
of the current accelerating universe. In this scenario phantom scalar field
conformally coupled to gravity drives the accelerating phase of the universe.
In our model $\Lambda$CDM appears as a global attractor in the phase space. In
this paper we investigate observational constraints on this scenario from
recent measurements of distant supernovae type Ia, CMB R shift, BAO and $H(z)$
observational data. The Bayesian methods of model selection are used in
comparison the model with concordance $\Lambda$CDM one as well as with model
with dynamical dark energy parametrised by linear form. We conclude that
$\Lambda$CDM is favoured over FRW model with dynamical oscillating dark energy.
Our analysis also demonstrate that FRW model with oscillating dark energy is
favoured over FRW model with decaying dark energy parametrised in linear way.


title:
Irrational vs. rational charge and statistics in two-dimensional quantum
  systems

abstract:
  We show that quasiparticle excitations with irrational charge and irrational
exchange statistics exist in tight-biding systems described, in the continuum
approximation, by the Dirac equation in (2+1)-dimensional space and time. These
excitations can be deconfined at zero temperature, but when they are, the
charge re-rationalizes to the value 1/2 and the exchange statistics to that of
"quartons" (half-semions).

categories: cond-mat.str-el cond-mat.mes-hall hep-th math-ph math.MP


title: Lifetime Difference in B_s mixing: Standard Model and beyond

abstract:
  We present a calculation of 1/m^2_b corrections to the lifetime differences
of B_s mesons \Delta \Gamma_s in the heavy-quark expansion. We find that they
are small to significantly affect \Delta \Gamma_s and present the result for
lifetime difference including non-perturbative 1/m_b and 1/m_b^2 corrections.
We also analyze the generic \Delta B = 1 New Physics contributions to \Delta
\Gamma_s and provide several examples.


title: A Note on Heterotic Dualities via M-theory

abstract:
  We show that a class of torsional compactifications of the heterotic string
are dual to conventional Kahler heterotic string compactifications. This
observation follows from the recently proposed analogue of the c-map for the
heterotic string.


title: Translations and dynamics

abstract:
  We analyze the role played by local translational symmetry in the context of
gauge theories of fundamental interactions. Translational connections and
fields are introduced, with special attention being paid to their universal
coupling to other variables, as well as to their contributions to field
equations and to conserved quantities.


title:
Fractal valence bond loops in a long-range Heisenberg model at
  criticality

abstract:
  We present a valence bond theory of the spin-S quantum Heisenberg model. For
nonfrustracting, local exchange and dimension d > 1, it predicts a resonating
ground state with bond amplitudes h(r) ~ (a^2+r^2)^(-p/2) and decay exponent
p=d+1. Different values of p can be achieved by introducing frustrating (p >
d+1) or nonfrustrating (p < d+1) long-range interactions. For d=2, but not d=3,
there is a critical value of the decay exponent p_c above which the ground
state is a spin liquid. The phase transition is analogous to quantum
percolation, with fractal valence bond loops playing the role of percolating
clusters. The critical exponents are continuously tunable along the phase
boundary p=p_c(a,S).


title: Dimers and Orientifolds

abstract:
  We introduce new techniques based on brane tilings to investigate D3-branes
probing orientifolds of toric Calabi-Yau singularities. With these new tools,
one can write down many orientifold models and derive the resulting low-energy
gauge theories living on the D-branes. Using the set of ideas in this paper one
recovers essentially all orientifolded theories known so far. Furthermore, new
orientifolds of non-orbifold toric singularities are obtained. The possible
applications of the tools presented in this paper are diverse. One particular
application is the construction of models which feature dynamical supersymmetry
breaking as well as the computation of D-instanton induced superpotential
terms.


title: The distribution of smooth numbers in arithmetic progressions

abstract:
  For a wide range of $x$ and $y$ we show that ${\Cal S}(x,y)$, the set of
integers below $x$ composed only of prime factors below $y$, is equidistributed
in the reduced residue classes $\pmod q$ for all $q<y^{4\sqrt{e}-\epsilon}$.
This improves earlier work of Granville; any improvement of this range of $q$
would have interesting consequences for Vinogradov's conjecture on the least
quadratic non-residue. For larger ranges of $q$ we prove the existence of a
large subgroup of the group of reduced residues such that ${\Cal S}(x,y)$ is
equidistributed within cosets of that subgroup.


title: Categorical aspects of toric topology

abstract:
  We argue for the addition of category theory to the toolkit of toric
topology, by surveying recent examples and applications. Our case is made in
terms of toric spaces X_K, such as moment-angle complexes Z_K, quasitoric
manifolds M, and Davis-Januszkiewicz spaces DJ(K). We first exhibit X_K as the
homotopy colimit of a diagram of spaces over the small category cat(K), whose
objects are the faces of a finite simplicial complex K and morphisms their
inclusions. Then we study the corresponding cat(K)-diagrams in various
algebraic Quillen model categories, and interpret their homotopy colimits as
algebraic models for X_K. Such models encode many standard algebraic
invariants, and their existence is assured by the Quillen structure. We provide
several illustrative calculations, often over the rationals, including proofs
that quasitoric manifolds (and various generalisations) are rationally formal;
that the rational Pontrjagin ring of the loop space \Omega DJ(K) is isomorphic
to the quadratic dual of the Stanley-Reisner algebra Q[K] for flag complexes K;
and that DJ(K) is coformal precisely when K is flag. We conclude by describing
algebraic models for the loop space \Omega DJ(K) for any complex K, which mimic
our previous description as a homotopy colimit of topological monoids.


title: Anatomy of the binary black hole recoil: A multipolar analysis

abstract:
  We present a multipolar analysis of the gravitational recoil computed in
recent numerical simulations of binary black hole (BH) coalescence, for both
unequal masses and non-zero, non-precessing spins. We show that multipole
moments up to and including l=4 are sufficient to accurately reproduce the
final recoil velocity (within ~2%) and that only a few dominant modes
contribute significantly to it (within ~5%). We describe how the relative
amplitudes, and more importantly, the relative phases, of these few modes
control the way in which the recoil builds up throughout the inspiral, merger,
and ringdown phases. We also find that the numerical results can be reproduced
by an ``effective Newtonian'' formula for the multipole moments obtained by
replacing the radial separation in the Newtonian formulae with an effective
radius computed from the numerical data. Beyond the merger, the numerical
results are reproduced by a superposition of three Kerr quasi-normal modes
(QNMs). Analytic formulae, obtained by expressing the multipole moments in
terms of the fundamental QNMs of a Kerr BH, are able to explain the onset and
amount of ``anti-kick'' for each of the simulations. Lastly, we apply this
multipolar analysis to help explain the remarkable difference between the
amplitudes of planar and non-planar kicks for equal-mass spinning black holes.


title:
Muon Acceleration to 750 GeV in the Tevatron Tunnel for a 1.5 TeV mu+
  mu- Collider

abstract:
  Muon acceleration from 30 to 750 GeV in 72 orbits using two rings in the
1000m radius Tevatron tunnel is explored. The first ring ramps at 400 Hz and
accelerates muons from 30 to 400 GeV in 28 orbits using 14 GV of 1.3 GHz
superconducting RF. The ring duplicates the Fermilab 400 GeV main ring FODO
lattice, which had a 61m cell length. Muon survival is 80%. The second ring
accelerates muons from 400 to 750 GeV in 44 orbits using 8 GV of 1.3 GHz
superconducting RF. The 30 T/m main ring quadrupoles are lengthened 87% to
3.3m. The four main ring dipoles in each half cell are replaced by three
dipoles which ramp at 550 Hz from -1.8T to +1.8T interleaved with two 8T fixed
superconducting dipoles. The ramping and superconducting dipoles oppose each
other at 400 GeV and act in unison at 750 GeV. Muon survival is 92%. Two mm
copper wire, 0.28mm grain oriented silicon steel laminations, and a low duty
cycle mitigate eddy current losses. Low emittance muon bunches allow small
aperatures and permit magnets to ramp with a few thousand volts. Little civil
construction is required. The tunnel exists.


title: Learning from dependent observations

abstract:
  In most papers establishing consistency for learning algorithms it is assumed
that the observations used for training are realizations of an i.i.d. process.
In this paper we go far beyond this classical framework by showing that support
vector machines (SVMs) essentially only require that the data-generating
process satisfies a certain law of large numbers. We then consider the
learnability of SVMs for $\a$-mixing (not necessarily stationary) processes for
both classification and regression, where for the latter we explicitly allow
unbounded noise.


title:
Cold Disks: Spitzer Spectroscopy of Disks around Young Stars with Large
  Gaps

abstract:
  We have identified four circumstellar disks with a deficit of dust emission
from their inner 15-50 AU. All four stars have F-G spectral type, and were
uncovered as part of the Spitzer Space Telescope ``Cores to Disks'' Legacy
Program Infrared Spectrograph (IRS) first look survey of ~100 pre-main sequence
stars. Modeling of the spectral energy distributions indicates a reduction in
dust density by factors of 100-1000 from disk radii between ~0.4 and 15-50 AU,
but with massive gas-rich disks at larger radii. This large contrast between
the inner and outer disk has led us to use the term `cold disks' to distinguish
these unusual systems. However, hot dust [0.02-0.2 Mmoon] is still present
close to the central star (R ~0.8 AU). We introduce the 30/13 micron, flux
density ratio as a new diagnostic for identifying cold disks. The mechanisms
for dust clearing over such large gaps are discussed. Though rare, cold disks
are likely in transition from an optically thick to an optically thin state,
and so offer excellent laboratories for the study of planet formation.


title: The Quasar Accretion Disk Size - Black Hole Mass Relation

abstract:
  We use the microlensing variability observed for nine gravitationally lensed
quasars to show that the accretion disk size at 2500 Angstroms is related to
the black hole mass by log(R_2500/cm) = (15.6+-0.2) +
(0.54+-0.28)log(M_BH/10^9M_sun). This scaling is consistent with the
expectation from thin disk theory (R ~ M_BH^(2/3)), but it implies that black
holes radiate with relatively low efficiency, log(eta) = -1.29+-0.44 +
log(L/L_E) where eta=L/(Mdot c^2). These sizes are also larger, by a factor of
~3, than the size needed to produce the observed 0.8 micron quasar flux by
thermal radiation from a thin disk with the same T ~ R^(-3/4) temperature
profile. More sophisticated disk models are clearly required, particularly as
our continuing observations improve the precision of the measurements and yield
estimates of the scaling with wavelength and accretion rate.


title: The Nature of Stellar Winds in the Star-Disk Interaction

abstract:
  Stellar winds may be important for angular momentum transport from accreting
T Tauri stars, but the nature of these winds is still not well-constrained. We
present some simulation results for hypothetical, hot (~1e6 K) coronal winds
from T Tauri stars, and we calculate the expected emission properties. For the
high mass loss rates required to solve the angular momentum problem, we find
that the radiative losses will be much greater than can be powered by the
accretion process. We place an upper limit to the mass loss rate from
accretion-powered coronal winds of ~1e-11 solar masses per year. We conclude
that accretion powered stellar winds are still a promising scenario for solving
the stellar angular momentum problem, but the winds must be cool (~1e4 K) and
thus are not driven by thermal pressure.


title:
Quasi-angular momentum of Bose and Fermi gases in rotating optical
  lattices

abstract:
  The notion of quasi-angular momentum is introduced to label the eigenstates
of a Hamiltonian with a discrete rotational symmetry. This concept is recast in
an operatorial form where the creation and annihilation operators of a Hubbard
Hamiltonian carry units of quasi-angular momentum. Using this formalism, the
ground states of ultracold gases of non-interacting fermions in rotating
optical lattices are studied as a function of rotation, and transitions between
states of different quasi-angular momentum are identified. In addition,
previous results for strongly-interacting bosons are re-examined and compared
to the results for non-interacting fermions. Quasi-angular momentum can be used
to distinguish between these two cases. Finally, an experimentally accessible
signature of quasi-angular momentum is identified in the momentum distributions
of single-particle eigenstates.


title:
The Teichm\"uller distance between finite index subgroups of
  $PSL_2(\mathbb{Z})$

abstract:
  For a given $\epsilon >0$, we show that there exist two finite index
subgroups of $PSL_2(\mathbb{Z})$ which are $(1+\epsilon)$-quasisymmetrically
conjugated and the conjugation homeomorphism is not conformal. This implies
that for any $\epsilon>0$ there are two finite regular covers of the Modular
once punctured torus $T_0$ (or just the Modular torus) and a
$(1+\epsilon)$-quasiconformal between them that is not homotopic to a conformal
map. As an application of the above results, we show that the orbit of the
basepoint in the Teichm\"uller space $T(\S)$ of the punctured solenoid $\S$
under the action of the corresponding Modular group (which is the mapping class
group of $\S$ \cite{NS}, \cite{Odd}) has the closure in $T(\S)$ strictly larger
than the orbit and that the closure is necessarily uncountable.


title: Dynamic range of hypercubic stochastic excitable media

abstract:
  We study the response properties of d-dimensional hypercubic excitable
networks to a stochastic stimulus. Each site, modelled either by a three-state
stochastic susceptible-infected-recovered-susceptible system or by the
probabilistic Greenberg-Hastings cellular automaton, is continuously and
independently stimulated by an external Poisson rate h. The response function
(mean density of active sites rho versus h) is obtained via simulations (for
d=1, 2, 3, 4) and mean field approximations at the single-site and pair levels
(for all d). In any dimension, the dynamic range of the response function is
maximized precisely at the nonequilibrium phase transition to self-sustained
activity, in agreement with a reasoning recently proposed. Moreover, the
maximum dynamic range attained at a given dimension d is a decreasing function
of d.

categories: q-bio.NC cond-mat.dis-nn cond-mat.stat-mech nlin.CG physics.bio-ph


title:
Path integral representations in noncommutative quantum mechanics and
  noncommutative version of Berezin-Marinov action

abstract:
  It is known that actions of field theories on a noncommutative space-time can
be written as some modified (we call them $\theta$-modified) classical actions
already on the commutative space-time (introducing a star product). Then the
quantization of such modified actions reproduces both space-time
noncommutativity and usual quantum mechanical features of the corresponding
field theory. The $\theta$-modification for arbitrary finite-dimensional
nonrelativistic system was proposed by Deriglazov (2003). In the present
article, we discuss the problem of constructing $\theta$-modified actions for
relativistic QM. We construct such actions for relativistic spinless and
spinning particles. The key idea is to extract $\theta$-modified actions of the
relativistic particles from path integral representations of the corresponding
noncommtative field theory propagators. We consider Klein-Gordon and Dirac
equations for the causal propagators in such theories. Then we construct for
the propagators path-integral representations. Effective actions in such
representations we treat as $\theta$-modified actions of the relativistic
particles. To confirm the interpretation, we quantize canonically these
actions. Thus, we obtain the Klein-Gordon and Dirac equations in the
noncommutative field theories. The $\theta$-modified action of the relativistic
spinning particle is just a generalization of the Berezin-Marinov
pseudoclassical action for the noncommutative case.


title:
On the maximum size of an anti-chain of linearly separable sets and
  convex pseudo-discs

abstract:
  We show that the maximum cardinality of an anti-chain composed of
intersections of a given set of n points in the plane with half-planes is close
to quadratic in n. We approach this problem by establishing the equivalence
with the problem of the maximum monotone path in an arrangement of n lines. For
a related problem on antichains in families of convex pseudo-discs we can
establish the precise asymptotic bound: it is quadratic in n. The sets in such
a family are characterized as intersections of a given set of n points with
convex sets, such that the difference between the convex hulls of any two sets
is nonempty and connected.


title:
Stellar Populations in the Outskirts of the Small Magellanic Cloud: No
  Outer Edge Yet

abstract:
  We report the detection of intermediate-age and old stars belonging to the
SMC at 6.5 kpc from the SMC center in the southern direction. We show, from the
analysis of three high quality 34\arcmin $\times$ 33\arcmin CMDs, that the age
composition of the stellar population is similar at galactocentric distances of
$\thicksim$4.7 kpc, $\thicksim$5.6 kpc, and $\thicksim$6.5 kpc. The surface
brightness profile of the SMC follows an exponential law, with no evidence of
truncation, all the way out to 6.5 kpc. These results, taken together, suggest
that the SMC `disk' population is dominating over a possible old Milky Way-like
stellar halo, and that the SMC may be significantly larger than previously
thought.


title: Differential Equations Driven by Gaussian Signals I

abstract:
  We consider multi-dimensional Gaussian processes and give a new condition on
the covariance, simple and sharp, for the existence of stochastic area(s).
Gaussian rough paths are constructed with a variety of weak and strong
approximation results. Together with a new RKHS embedding, we obtain a powerful
- yet conceptually simple - framework in which to analysize differential
equations driven by Gaussian signals in the rough paths sense.


title: Interpolation of SUSY quantum mechanics

abstract:
  Interpolation of two adjacent Hamiltonians in SUSY quantum mechanics
$H_s=(1-s)A^{\dagger}A + sAA^{\dagger}$, $0\le s\le 1$ is discussed together
with related operators. For a wide variety of shape-invariant degree one
quantum mechanics and their `discrete' counterparts, the interpolation
Hamiltonian is also shape-invariant, that is it takes the same form as the
original Hamiltonian with shifted coupling constant(s).


title: How many random edges make a dense hypergraph non-2-colorable?

abstract:
  We study a model of random uniform hypergraphs, where a random instance is
obtained by adding random edges to a large hypergraph of a given density. We
obtain a tight bound on the number of random edges required to ensure
non-2-colorability. We prove that for any k-uniform hypergraph with
Omega(n^{k-epsilon}) edges, adding omega(n^{k epsilon/2}) random edges makes
the hypergraph almost surely non-2-colorable. This is essentially tight, since
there is a 2-colorable hypergraph with Omega(n^{k-\epsilon}) edges which almost
surely remains 2-colorable even after adding o(n^{k \epsilon / 2}) random
edges.


title:
Occupation time fluctuations of Poisson and equilibrium branching
  systems in critical and large dimensions

abstract:
  Limit theorems are presented for the rescaled occupation time fluctuation
process of a critical finite variance branching particle system in
$\mathbb{R}^{d}$ with symmetric $\alpha$-stable motion starting off from either
a standard Poisson random field or the equilibrium distribution for critical
$d=2\alpha$ and large $d>2\alpha$ dimensions. The limit processes are
generalised Wiener processes. The obtained convergence is in space-time,
finite-dimensional distributions sense. With the addtional assumption on the
branching law we obtain functional convergence.


title: Signatures of black holes at the LHC

abstract:
  Signatures of black hole events at CERN's Large Hadron Collider are
discussed. Event simulations are carried out with the Fortran Monte Carlo
generator CATFISH. Inelasticity effects, exact field emissivities, color and
charge conservation, corrections to semiclassical black hole evaporation,
gravitational energy loss at formation and possibility of a black hole remnant
are included in the analysis.


title:
Pressure induced enhancement of ferroelectricity in multiferroic
  $R$Mn$_2$O$_5$($R$=Tb,Dy, and Ho)

abstract:
  Measurements of ferroelectric polarization and dielectric constant were done
on $R$Mn$_2$O$_5$ ($R$=Tb, Dy, and Ho) with applied hydrostatic pressures of up
to 18 kbar. At ambient pressure, distinctive anomalies were observed in the
temperature profile of both physical properties at critical temperatures
marking the onset of long range AFM order (T$_{N1}$), ferroelectricity
(T$_{C1}$) as well as at temperatures when anomalous changes in the
polarization, dielectric constant and spin wave commensurability have been
previously reported. In particular, the step in the dielectric constant at low
temperatures (T$_{C2}$), associated with both a drop in the ferroelectric
polarization and an incommensurate magnetic structure, was shown to be suddenly
quenched upon passing an $R$-dependent critical pressure. This was shown to
correlate with the stabilization of the high ferroelectric polarization state
which is coincident with the commensurate magnetic structure. The observation
is suggested to be due to a pressure induced phase transition into a
commensurate magnetic structure as exemplified by the pressure-temperature
($p$-$T$) phase diagrams constructed in this work. The $p$-$T$ phase diagrams
are determined for all three compounds.


title:
Amorphous silica modeled with truncated and screened Coulomb
  interactions: A molecular dynamics simulation study

abstract:
  We show that finite-range alternatives to the standard long-range BKS pair
potential for silica might be used in molecular dynamics simulations. We study
two such models that can be efficiently simulated since no Ewald summation is
required. We first consider the Wolf method, where the Coulomb interactions are
truncated at a cutoff distance r_c such that the requirement of charge
neutrality holds. Various static and dynamic quantities are computed and
compared to results from simulations using Ewald summations. We find very good
agreement for r_c ~ 10 Angstroms. For lower values of r_c, the long--range
structure is affected which is accompanied by a slight acceleration of dynamic
properties. In a second approach, the Coulomb interaction is replaced by an
effective Yukawa interaction with two new parameters determined by a force
fitting procedure. The same trend as for the Wolf method is seen. However,
slightly larger cutoffs have to be used in order to obtain the same accuracy
with respect to static and dynamic quantities as for the Wolf method.


title: Heavy Quark Mass Effects in PQCD and Heavy Flavor Parton Distributions

abstract:
  The systematic treatment of heavy quark mass effects in DIS in current CTEQ
global analysis is summarized. Applications of this treatment to the comparison
between theory and experimental data on DIS charm production are described. The
possibility of intrinsic charm in the nucleon is studied. The issue of
determining the charm mass in global analysis is discussed.


title:
Spreading of a density front in the K\"untz-Lavall\'ee model of porous
  media

abstract:
  We analyze spreading of a density front in the K\"untz-Lavall\'ee model of
porous media. In contrast to previous studies, where unusual properties of the
front were attributed to anomalous diffusion, we find that the front evolution
is controlled by normal diffusion and hydrodynamic flow, the latter being
responsible for apparent enhancement of the front propagation speed. Our
finding suggests that results of several recent experiments on porous media,
where anomalous diffusion was reported based on the density front propagation
analysis, should be reconsidered to verify the role of a fluid flow.


title:
Consistency of support vector machines for forecasting the evolution of
  an unknown ergodic dynamical system from observations with unknown noise

abstract:
  We consider the problem of forecasting the next (observable) state of an
unknown ergodic dynamical system from a noisy observation of the present state.
Our main result shows, for example, that support vector machines (SVMs) using
Gaussian RBF kernels can learn the best forecaster from a sequence of noisy
observations if (a) the unknown observational noise process is bounded and has
a summable $\alpha$-mixing rate and (b) the unknown ergodic dynamical system is
defined by a Lipschitz continuous function on some compact subset of
$\mathbb{R}^d$ and has a summable decay of correlations for Lipschitz
continuous functions. In order to prove this result we first establish a
general consistency result for SVMs and all stochastic processes that satisfy a
mixing notion that is substantially weaker than $\alpha$-mixing.


title:
Interference Alignment and the Degrees of Freedom for the K User
  Interference Channel

abstract:
  While the best known outerbound for the K user interference channel states
that there cannot be more than K/2 degrees of freedom, it has been conjectured
that in general the constant interference channel with any number of users has
only one degree of freedom. In this paper, we explore the spatial degrees of
freedom per orthogonal time and frequency dimension for the K user wireless
interference channel where the channel coefficients take distinct values across
frequency slots but are fixed in time. We answer five closely related
questions. First, we show that K/2 degrees of freedom can be achieved by
channel design, i.e. if the nodes are allowed to choose the best constant,
finite and nonzero channel coefficient values. Second, we show that if channel
coefficients can not be controlled by the nodes but are selected by nature,
i.e., randomly drawn from a continuous distribution, the total number of
spatial degrees of freedom for the K user interference channel is almost surely
K/2 per orthogonal time and frequency dimension. Thus, only half the spatial
degrees of freedom are lost due to distributed processing of transmitted and
received signals on the interference channel. Third, we show that interference
alignment and zero forcing suffice to achieve all the degrees of freedom in all
cases. Fourth, we show that the degrees of freedom $D$ directly lead to an
$\mathcal{O}(1)$ capacity characterization of the form
$C(SNR)=D\log(1+SNR)+\mathcal{O}(1)$ for the multiple access channel, the
broadcast channel, the 2 user interference channel, the 2 user MIMO X channel
and the 3 user interference channel with M>1 antennas at each node. Fifth, we
characterize the degree of freedom benefits from cognitive sharing of messages
on the 3 user interference channel.


title: Quantum Nash Equilibria and Quantum Computing

abstract:
  In this paper we review our earlier work on quantum computing and the Nash
Equilibrium, in particular, tracing the history of the discovery of new Nash
Equilibria and then reviewing the ways in which quantum computing may be
expected to generate new classes of Nash equilibria. We then extend this work
through a substantive analysis of examples provided by Meyer, Flitney, Iqbal
and Weigert and Cheon and Tsutsui with respect to quantized games, quantum game
strategies and the extension of Nash Equilibrium to solvable games in Hilbert
space. Finally, we review earlier work by Sato, Taiji and Ikegami on non-linear
computation and computational classes by way of reference to coherence,
decoherence and quantum computating systems.

categories: q-fin.GN physics.comp-ph physics.soc-ph q-fin.CP


title: Excited state quantum phase transitions in many-body systems

abstract:
  Phenomena analogous to ground state quantum phase transitions have recently
been noted to occur among states throughout the excitation spectra of certain
many-body models. These excited state phase transitions are manifested as
simultaneous singularities in the eigenvalue spectrum (including the gap or
level density), order parameters, and wave function properties. In this
article, the characteristics of excited state quantum phase transitions are
investigated. The finite-size scaling behavior is determined at the mean field
level. It is found that excited state quantum phase transitions are universal
to two-level bosonic and fermionic models with pairing interactions.


title: Projective Coordinates and Projective Space Limit

abstract:
  The "projective lightcone limit" has been proposed as an alternative
holographic dual of an AdS space. It is a new type of group contraction for a
coset G/H preserving the isometry group G but changing H. In contrast to the
usual group contraction, which changes G preserving the spacetime dimension, it
reduces the dimensions of the spacetime on which G is realized. The obtained
space is a projective space on which the isometry is realized as a linear
fractional transformation. We generalize and apply this limiting procedure to
the "Hopf reduction" and obtain (n-1)-dimensional complex projective space from
(2n-1)-dimensional sphere preserving SU(n) symmetry.


title:
Fault-tolerant linear optical quantum computing with small-amplitude
  coherent states

abstract:
  Quantum computing using two optical coherent states as qubit basis states has
been suggested as an interesting alternative to single photon optical quantum
computing with lower physical resource overheads. These proposals have been
questioned as a practical way of performing quantum computing in the short term
due to the requirement of generating fragile diagonal states with large
coherent amplitudes. Here we show that by using a fault-tolerant error
correction scheme, one need only use relatively small coherent state amplitudes
($\alpha > 1.2$) to achieve universal quantum computing. We study the effects
of small coherent state amplitude and photon loss on fault tolerance within the
error correction scheme using a Monte Carlo simulation and show the quantity of
resources used for the first level of encoding is orders of magnitude lower
than the best known single photon scheme. %We study this reigem using a Monte
Carlo simulation and incorporate %the effects of photon loss in this
simulation.


title: What's the matter at RHIC?

abstract:
  I present here a concise review of the experimental results obtained at the
Relativistic Heavy Ion Collider (RHIC), which shed light on the hot and dense
quark gluon matter produced at these high temperature and density conditions.


title: Expected Anomalies in the Fossil Record

abstract:
  The problem of intermediates in the fossil record has been frequently
discussed ever since Darwin. The extent of `gaps' (missing transitional stages)
has been used to argue against gradual evolution from a common ancestor.
Traditionally, gaps have often been explained by the improbability of
fossilization and the discontinuous selection of found fossils. Here we take an
analytical approach and demonstrate why, under certain sampling conditions, we
may not expect intermediates to be found. Using a simple null model, we show
mathematically that the question of whether a taxon sampled from some time in
the past is likely to be morphologically intermediate to other samples (dated
earlier and later) depends on the shape and dimensions of the underlying
phylogenetic tree that connects the taxa, and the times from which the fossils
are sampled.


title: An Algebra of Quantum Processes

abstract:
  We introduce an algebra qCCS of pure quantum processes in which no classical
data is involved, communications by moving quantum states physically are
allowed, and computations is modeled by super-operators. An operational
semantics of qCCS is presented in terms of (non-probabilistic) labeled
transition systems. Strong bisimulation between processes modeled in qCCS is
defined, and its fundamental algebraic properties are established, including
uniqueness of the solutions of recursive equations. To model sequential
computation in qCCS, a reduction relation between processes is defined. By
combining reduction relation and strong bisimulation we introduce the notion of
strong reduction-bisimulation, which is a device for observing interaction of
computation and communication in quantum systems. Finally, a notion of strong
approximate bisimulation (equivalently, strong bisimulation distance) and its
reduction counterpart are introduced. It is proved that both approximate
bisimilarity and approximate reduction-bisimilarity are preserved by various
constructors of quantum processes. This provides us with a formal tool for
observing robustness of quantum processes against inaccuracy in the
implementation of its elementary gates.


title:
Target mass corrections and twist-3 in the nucleon spin structure
  functions

abstract:
  The Nachtmann moment is employed to study the contribution of twist-3
operator to the nucleon spin structure functions. Target mass corrections to
the Cornwall-Norton moments of the spin structure functions $g_{1,2}$ are
discussed. It is found that the corrections play a sizeable role to the
contribution of the twist-3 $\tilde d_2$ extracted from the Cornwall-Norton
moments.


title: Melting of the vortex lattice in layered superconductors

abstract:
  The structure function of the vortex lattice of layered superconductor is
calculated to one-loop order. Based on a phenomenological melting criterion
concerning the Debye-Waller factor, we calculate the melting line of the vortex
lattice, and compare our results to Monte Carlo simulation and experiment. We
find that our results are quantitatively in good agreement with the Monte Carlo
results. Moreover, our analytic calculation of the melting line of BSCCO fits
the experiment reasonably well in a temperature range not far from Tc.


title:
The radius and mass of the subgiant star bet Hyi from interferometry and
  asteroseismology

abstract:
  We have used the Sydney University Stellar Interferometer (SUSI) to measure
the angular diameter of beta Hydri. This star is a nearby G2 subgiant whose
mean density was recently measured with high precision using asteroseismology.
We determine the radius and effective temperature of the star to be
1.814+/-0.017 R_sun (0.9%) and 5872+/-44 K (0.7%) respectively. By combining
this value with the mean density, as estimated from asteroseismology, we make a
direct estimate of the stellar mass. We find a value of 1.07+/-0.03 M_sun
(2.8%), which agrees with published estimates based on fitting in the H-R
diagram, but has much higher precision. These results place valuable
constraints on theoretical models of beta Hyi and its oscillation frequencies.


title: Implementation of three-qubit Grover search in cavity QED

abstract:
  Using resonant interaction of three Rydberg atoms with a single-mode
microwave cavity, we consider a realization of three-qubit Grover search
algorithm in the presence of weak cavity decay, based on a previous idea for
three-qubit quantum gate [Phys. Rev. A 73, 064304 (2006)]. We simulate the
searching process under the influence of the cavity decay and show that our
scheme could be achieved efficiently to find the marked state with high
fidelity. The required operations are very close to the reach with current
cavity QED techniques.


title:
Label-setting methods for Multimode Stochastic Shortest Path problems on
  graphs

abstract:
  Stochastic shortest path (SSP) problems arise in a variety of discrete
stochastic control contexts. An optimal solutions to such a problem is
typically computed using the value function, which can be found by solving the
corresponding dynamic programming equations. In the deterministic case, these
equations can be often solved by the highly efficient label-setting methods
(such as Dijkstra's and Dial's algorithms). In this paper we define and study a
class of Multimode Stochastic Shortest Path problems and develop sufficient
conditions for the applicability of label-setting methods. We illustrate our
approach on a number of discrete stochastic control examples. We also discuss
the relationship of SSPs with discretizations of static Hamilton-Jacobi
equations and provide an alternative derivation for several fast
(non-iterative) numerical methods for these PDEs.


title: Pricing Options on Defaultable Stocks

abstract:
  In this note, we develop stock option price approximations for a model which
takes both the risk o default and the stochastic volatility into account. We
also let the intensity of defaults be influenced by the volatility. We show
that it might be possible to infer the risk neutral default intensity from the
stock option prices. Our option price approximation has a rich implied
volatility surface structure and fits the data implied volatility well. Our
calibration exercise shows that an effective hazard rate from bonds issued by a
company can be used to explain the implied volatility skew of the implied
volatility of the option prices issued by the same company.


title:
Stability, Reactivity, and Aromaticity of Compounds of a Multivalent
  Superatom

abstract:
  In this communication we analyze the stability, reactivity and possible
aromatic behavior of two recently reported clusters (Reveles J. U.; Khanna S.
N.; Roach P. J.; Castleman A. W. jr. Proc. Natl. Acad. Sci, 2006, 103, 18405),
viz., Al7C- and Al7O- in the light of the principles of the maximum hardness
and minimum electrophilicity as well as the nucleus independent chemical shift
values.


title: Integral pinched 3-manifolds are space forms

abstract:
  In this paper we prove that, under an explicit integral pinching assumption
between the $L^2$-norm of the Ricci curvature and the $L^2$-norm of the scalar
curvature, a closed 3-manifold with positive scalar curvature admits an
Einstein metric with positive curvature. In particular this implies that the
manifold is diffeomorphic to a quotient of ${\Bbb S}^3$.


title: The BSSN formulation is a partially constrained evolution system

abstract:
  Relativistic simulations in 3+1 dimensions typically monitor the Hamiltonian
and momentum constraints during evolution, with significant violations of these
constraints indicating the presence of instabilities. In this paper we rewrite
the momentum constraints as first-order evolution equations, and show that the
popular BSSN formulation of the Einstein equations explicitly uses the momentum
constraints as evolution equations. We conjecture that this feature is a key
reason for the relative success of the BSSN formulation in numerical
relativity.


title:
Asymptotic enumeration of sparse nonnegative integer matrices with
  specified row and column sums

abstract:
  Let \svec = (s_1,...,s_m) and \tvec = (t_1,...,t_n) be vectors of nonnegative
integer-valued functions of m,n with equal sum S = sum_{i=1}^m s_i =
sum_{j=1}^n t_j. Let M(\svec,\tvec) be the number of m*n matrices with
nonnegative integer entries such that the i-th row has row sum s_i and the j-th
column has column sum t_j for all i,j. Such matrices occur in many different
settings, an important example being the contingency tables (also called
frequency tables) important in statistics. Define s=max_i s_i and t=max_j t_j.
Previous work has established the asymptotic value of M(\svec,\tvec) as
m,n\to\infty with s and t bounded (various authors independently, 1971-1974),
and when \svec,\tvec are constant vectors with m/n,n/m,s/n >= c/log n for
sufficiently large (Canfield and McKay, 2007). In this paper we extend the
sparse range to the case st=o(S^(2/3)). The proof in part follows a previous
asymptotic enumeration of 0-1 matrices under the same conditions (Greenhill,
McKay and Wang, 2006). We also generalise the enumeration to matrices over any
subset of the nonnegative integers that includes 0 and 1.


title:
Considering boundary conditions for black hole entropy in loop quantum
  gravity

abstract:
  We argue for black hole entropy in loop quantum gravity (LQG) by taking into
account the interpretation that there is no other side of the horizon. This
gives new values for the Barbero-Immirzi parameter which are fairly larger than
those considered before. We also discuss its consequences.


title:
Spin-orbit-assisted electron-phonon interaction and the magnetophonon
  resonance in semiconductor quantum wells

abstract:
  We introduce a spin-orbit assisted electron-phonon (e-ph) coupling mechanism
for carriers in semiconductor quantum wells and predict qualitatively the form
and shape of anticrossings between the cyclotron resonance (CR) and optical (LO
and TO) phonons. Since this e-ph interaction involves the electron spin it
makes the predicted TO-CR anticrossing dependent on the filling factor and
therefore on the polarization of the 2D electron gas in the quantum well.


title: Particle interference as a test of Lorentz-violating electrodynamics

abstract:
  In Lorentz-violating electrodynamics a steady current (and similarly a static
charge) generates both static magnetic and electric fields. These induced
fields, acting on interfering particles, change the interference pattern. We
find that particle interference experiments are sensitive to small Lorentz
violating effects, and thus they can be used to improve current bounds on some
Lorentz-violating parameters.


title: Large deviations for symmetrised empirical measures

abstract:
  In this paper we prove a Large Deviation Principle for the sequence of
symmetrised empirical measures $\frac{1}{n} \sum_{i=1}^{n}
\delta_{(X^n_i,X^n_{\sigma_n(i)})}$ where $\sigma_n$ is a random permutation
and $((X_i^n)_{1 \leq i \leq n})_{n \geq 1}$ is a triangular array of random
variables with suitable properties. As an application we show how this result
allows to improve the Large Deviation Principles for symmetrised
initial-terminal conditions bridge processes recently established by Adams,
Dorlas and K\"{o}nig.


title: Thermal rounding of the depinning transition

abstract:
  We study thermal effects at the depinning transition by numerical simulations
of driven one-dimensional elastic interfaces in a disordered medium. We find
that the velocity of the interface, evaluated at the critical depinning force,
can be correctly described with the power law $v\sim T^\psi$, where $\psi$ is
the thermal exponent. Using the sample-dependent value of the critical force,
we precisely evaluate the value of $\psi$ directly from the temperature
dependence of the velocity, obtaining the value $\psi = 0.15 \pm 0.01$. By
measuring the structure factor of the interface we show that both the
thermally-rounded and the T=0 depinning, display the same large-scale geometry,
described by an identical divergence of a characteristic length with the
velocity $\xi \propto v^{-\nu/\beta}$, where $\nu$ and $\beta$ are respectively
the T=0 correlation and depinning exponents. We discuss the comparison of our
results with previous estimates of the thermal exponent and the direct
consequences for recent experiments on magnetic domain wall motion in
ferromagnetic thin films.


title: The one-dimensional Schr\"{o}dinger-Newton equations

abstract:
  We prove an existence and uniqueness result for ground states of
one-dimensional Schr\"{o}dinger-Newton equations.


title: Gauss-Bonnet Gravity with Scalar Field in Four Dimensions

abstract:
  We give all exact solutions of the Einstein-Gauss-Bonnet Field Equations
coupled with a scalar field in four dimensions under certain assumptions.


title: Self-Organized Characteristics of the International System

abstract:
  Various self-organized characteristics of the international system can be
identified with the help of a complexity science perspective. The perspective
discussed in this article is based on various complexity science concepts and
theories, and concepts related to ecology and ecosystems. It can be argued that
the Great Power war dynamics of the international system in Europe during the
period 1480-1945, showed self-organized critical (SOC) characteristics,
resulting in a punctuated equilibrium dynamic. It seems that the
SOC-characteristics of the international system and the punctuated equilibrium
dynamic were - in combination with chaotic war dynamics - functional in a
process of social expansion in Europe. According to a model presented in this
article, population growth was a component of the driving force of the
international system during this time frame. The findings of this exploratory
research project contradict with generally held opinions in International
Relations theory.


title: Metallic Graphene Nanodisks

abstract:
  We explore the electronic properties of finite-length graphene nanoribbons as
well as graphene nanodisks with various sizes and shapes in quest of metallic
ones. For this purpose it is sufficient to search zero-energy states. We find
that there exist no zero-energy states in finite-length zigzag nanoribbons
though all infinite-length zigzag nanoribbons have zero-energy states. The
occurrence of zero-energy states is surprisingly rare. Among typical nanodisks,
only trigonal zigzag nanodisks have degenerate zero-energy states and show
metallic ferromagnetism, where the degeneracy can be controlled arbitrarily by
designing the size. A remarkable property is that the relaxation time is quite
large in spite of its small size in trigonal zigzag nanodisks.


title: A new concept and design of ferrite-based microwave vortex devices

abstract:
  In microwave resonant systems with ferrite samples, one becomes faced with
specific phase relations for the electromagnetic fields. Such specific phase
relations may lead to appearance of nontrivial states: electromagnetic
vortices. This paper provides some general ideas and design principles for
microwave devices with the field vortex structures.


title: Dispersion representations for hard exclusive processes

abstract:
  Several hard exclusive scattering processes admit a description in terms of
generalized parton distributions and perturbative hard-scattering kernels. Both
the physical amplitude and the hard-scattering kernels fulfill dispersion
relations. We give a detailed investigation of their consistency at all orders
in perturbation theory. The results shed light on the information about
generalized parton distributions that can be extracted from the real and
imaginary parts of exclusive amplitudes. They also provide a practical
consistency check for models of these distributions in which Lorentz invariance
is not exactly satisfied.


title:
Monte Carlo simulation of pressure-induced phase transitions in
  spin-crossover materials

abstract:
  Pressure-induced phase transitions of spin-crossover materials were simulated
by a Monte Carlo simulation in the constant pressure ensemble for the first
time. Here, as the origin of the cooperative interaction, we adopt elastic
interaction among the distortions of the lattice due to the difference of the
molecular sizes in different spin states, i.e., the high spin (HS) state and
the low spin (LS) state. We studied how the temperature dependence of the
ordering process changes with the pressure, and we obtained a standard sequence
of temperature dependences that has been found in changing other parameters
such as strength of the ligand field (S. Miyashita et al., Prog. Theor. Phys.
\textbf{114}, 719 (2005)). Various effects of pressure on the spin-crossover
ordering process are examined from a unified point of view.


title: Intrinsic Zeeman Effect in Graphene

abstract:
  The intrinsic Zeeman energy is precisely one half of the cyclotron energy for
electrons in graphene. As a result a Landau-level mixing occurs to create the
energy spectrum comprised of the $4j$-fold degenerated zero-energy level and
4-fold degenerated nonzero-energy levels in the $j$-layer graphene, where
$j=1,2,3$ for monolayer, bilayer and trilayer, respectively. The degeneracy
manifests itself in the quantum Hall (QH) effect. We study how the degeneracy
is removed by the Coulomb interactions. With respect to the zero-energy level,
an excitonic gap opens by making a BCS-type condensation of electron-hole pairs
at the filling factor $\nu =0$. It gives birth to the Ising QH ferromagnet at
$\nu =\pm 1$ for monolayer, $\nu =\pm 1,\pm 3$ for bilayer, and $\nu =\pm 1,\pm
3,\pm 5$ for trilayer graphene from the zero-energy degeneracy. With respect to
the nonzero-energy level, a remarkable consequence is derived that the
effective Coulomb potential depends on spins, since a single energy level
contains up-spin and down-spin electrons belonging to different Landau levels.
The spin-dependent Coulomb interaction leads to the valley polarization at $\nu
=\pm 4, \pm 8, \pm 12, ...$ for monolayer, $\nu =\pm 2, \pm 6, \pm 10, >...$
for bilayer, and $\nu =\pm 2,\pm 4, \pm 8, \pm 12, ...$ for trilayer graphene.


title: Low densities in asymmetric nuclear matter

abstract:
  Asymmetric nuclear matter is investigated in the low density region below the
nuclear saturation density. Microscopic calculations based on the Dirac
Brueckner Hartree-Fock (DBHF) approach with realistic nucleon-nucleon
potentials are used to adjust a low density functional. This functional is
constructed on a density expansion of the relativistic mean field theory which
allows a clear interpretation of the role of the mesons to the equation of
state. It is shown that a correction term should be added to the functional in
order to take into account the effects beyond the mean field. Two functionals
with different corrections are obtained. Those functionals converge to predict
a reduction of the spinodal zone in asymmetric nuclear matter by about 15-20%
and an isoscalar unstable mode closer to the constant Z/A direction than the
functional without correction.


title: Evolutionary Conditions in the Dissipative MHD System Revisited

abstract:
  The evolutionary conditions for the dissipative continuous
magnetohydrodynamic (MHD) shocks are studied. We modify Hada's approach in the
stability analysis of the MHD shock waves. The matching conditions between
perturbed shock structure and asymptotic wave modes shows that all types of the
MHD shocks, including the intermediate shocks, are evolutionary and perturbed
solutions are uniquely defined. We also adopt our formalism to the MHD shocks
in the system with resistivity without viscosity, which is often used in
numerical simulation, and show that all types of shocks that are found in the
system satisfy the evolutionary condition and perturbed solutions are uniquely
defined. These results suggest that the intermediate shocks may appear in
reality.


title: No Higgs at the LHC ?! A case for the ILC

abstract:
  I discuss the question whether it is possible that the LHC will find no
signal for the Higgs particle. It is argued that in this case singlet scalars
should be present that could play an important role in astroparticle physics. A
critical view at the existing electroweak data shows that this possibility
might be favored over the simplest standard model. In this case one needs the
ILC in order to study the Higgs sector.


title: Relativistic Dynamics of Multi-BPS D-vortices and Straight BPS D-strings

abstract:
  Moduli space dynamics of multi-D-vortices from D2${\bar {\rm D}}$
(equivalently, parallel straight D-strings from D3${\bar {\rm D}}$3) is
systematically studied. For the BPS D-vortices, we show through exact
calculations that the classical motion of randomly-distributed $n$ D-vortices
is governed by a relativistic Lagrangian of free massive point-particles. When
the head-on collision of two identical BPS D-vortices of zero radius is
considered, it predicts either 90${}^{\circ}$ scattering or 0${}^{\circ}$
scattering equivalent to 180${}^{\circ}$ scattering. Since the former leads to
a reconnection of two identical D-strings and the latter does to a case of
their passing through each other, two possibilities are consistent with the
prediction of string theory. It is also shown that the force between two
non-BPS vortices is repulsive. Although the obtained moduli space dynamics of
multi-BPS-D-vortices is exact in classical regime, the quantum effect of an
F-string pair production should be included in determining the probabilities of
the reconnection and the passing through for fast-moving cosmic superstrings.


title:
Spatial correlation of linear and nonlinear electron transport in
  superconducting microwave resonator: laser scanning microscopy analysis

abstract:
  Spatially-resolved techniques of laser scanning microscopy (LSM) have been
used to image simultaneously the spatial variations of (i) rf current flow,
J$_RF$(x,y), of (ii) areas of resistive dissipation and (iii) the sources of
microwave nonlinearity (NL) in an operating superconducting resonator. The RF
power dependent spatial evolution of these linear and NL microwave properties
in the meander strip YBCO/LAO superconducting resonator have been LSM probed at
different temperatures below Tc. The influence of both topologies of the
twin-domain YBCO structure and of J$_RF$(x,y) peaks at the edges of
superconducting strip line on its NL properties was analyzed in detail with a
micron-scale spatial resolution. Result shows the resistive origin of the
dominant sources of microwave NLs


title: SM scalar and extra singlet(s)

abstract:
  I discuss the question whether it is possible that the LHC will find no
signal for the Higgs boson. It is argued that in this case singlet scalars
should be present that could play an important role in astroparticle physics. A
critical view at the existing electroweak data shows that this possibility
might be favored over the simplest standard model. In this case one needs the
ILC in order to study the Higgs sector.


title: Effect of Co and Fe on the inverse magnetocaloric properties of Ni-Mn-Sn

abstract:
  At certain compositions Ni-Mn-$X$ Heusler alloys ($X$: group IIIA-VA
elements) undergo martensitic transformations, and many of them exhibit inverse
magnetocaloric effects. In alloys where $X$ is Sn, the isothermal entropy
change is largest among the Heusler alloys, particularly in
Ni$_{50}$Mn$_{37}$Sn$_{13}$ where it reaches a value of 20 Jkg$^{-1}$K$^{-1}$
for a field of 5T. We substitute Ni with Fe and Co in this alloy, each in
amounts of 1 at% and 3 at% to perturb the electronic concentration and examine
the resulting changes in the magnetocaloric properties. Increasing both Fe and
Co concentrations causes the martensitic transition temperature to decrease,
whereby the substitution by Co at both compositions or substituting 1 at% Fe
leads to a decrease in the magnetocaloric effect. On the other hand, the
magnetocaloric effect in the alloy with 3 at% Fe leads to an increase in the
value of the entropy change to about 30 Jkg$^{-1}$K$^{-1}$ at 5T.


title: The curvature perturbation in a box

abstract:
  The stochastic properties of cosmological perturbations are best defined
through the Fourier expansion in a finite box. I discuss the reasons for that
with reference the curvature perturbation, and explore some issues arising from
it.


title: On Fox and augmentation quotients of semidirect products

abstract:
  Let $G$ be a group which is the semidirect product of a normal subgroup $N$
and some subgroup $T$. Let $I^n(G)$, $n\ge 1$, denote the powers of the
augmentation ideal $I(G)$ of the group ring $\Z(G)$. Using homological methods
the groups $Q_n(G,H) = I^{n-1}(G)I(H)/I^{n}(G)I(H)$, $H=G,N,T$, are
functorially expressed in terms of enveloping algebras of certain Lie rings
associated with $N$ and $T$, in the following cases: for $n\le 4$ and arbitrary
$G,N,T$ (except from one direct summand of $Q_4(G,N)$), and for all $n\ge 2$ if
certain filtration quotients of $N$ and $T$ are torsionfree.


title: Detecting bubbles in exotic nuclei

abstract:
  The occurrence of a bubble, due to an inversion of s$_{1/2}$ state with the
state usually located above, is investigated. Proton bubbles in neutron-rich
Argon isotopes are optimal candidates. Pairing effects which can play against
the bubble formation are evaluated. They cannot prevent bubble formation in
very neutron-rich argon isotopes such as $^{68}$Ar. This pleads for a
measurement of the charge density of neutron-rich argon isotopes in the
forthcoming years, with the advent of electron scattering experiments in next
generation exotic beam facilities such as FAIR or RIBF.


title: Polarization types of isogenous Prym-Tyurin varieties

abstract:
  Let p:C-->Y be a covering of smooth, projective curves which is a composition
of \pi:C-->C' of degree 2 and g:C'-->Y of degree n. Let f:X-->Y be the covering
of degree 2^n, where the curve X parametrizes the liftings in C^{(n)} of the
fibers of g:C'-->Y. Let P(X,\delta) be the associated Prym-Tyurin variety,
known to be isogenous to the Prym variety P(C,C'). Most of the results in the
paper focus on calculating the polarization type of the restriction of the
canonical polarization of JX on P(X,\delta). We obtain the polarization type
when n=3. When Y=P^1 we conjecture that P(X,\delta) is isomorphic to the dual
of the Prym variety P(C,C'). This was known when n=2, we prove it when n=3, and
for arbitrary n if \pi:C-->C' is \'{e}tale. Similar results are obtained for
some other types of coverings.


title: Performance Analysis of Publish/Subscribe Systems

abstract:
  The Desktop Grid offers solutions to overcome several challenges and to
answer increasingly needs of scientific computing. Its technology consists
mainly in exploiting resources, geographically dispersed, to treat complex
applications needing big power of calculation and/or important storage
capacity. However, as resources number increases, the need for scalability,
self-organisation, dynamic reconfigurations, decentralisation and performance
becomes more and more essential. Since such properties are exhibited by P2P
systems, the convergence of grid computing and P2P computing seems natural. In
this context, this paper evaluates the scalability and performance of P2P tools
for discovering and registering services. Three protocols are used for this
purpose: Bonjour, Avahi and Free-Pastry. We have studied the behaviour of
theses protocols related to two criteria: the elapsed time for registrations
services and the needed time to discover new services. Our aim is to analyse
these results in order to choose the best protocol we can use in order to
create a decentralised middleware for desktop grid.


title: Willmore Legendrian surfaces in pseudoconformal 5-sphere

abstract:
  Let $ X: M \hook S^5$ be a compact Legendrian surface in pseudoconformal(CR)
5-sphere. We introduce a pseudoconformally invariant Willmore type second order
functional $ \W(X)$, and study its critical points called Willmore Legendrian
surfaces. The fifth order structure equations show that Willmore dual can be
defined for a class of Willmore Legendrian surfaces. Moreover when this dual is
constant, Willmore Legendrian surface admits a Weierstra\ss type representation
in terms of immersed meromorphic curve in $ \C^2$ satisfying an appropriate
real period condition via pseudoconformal stereographic projection. We show
that every compact Riemann surface admits a generally one to one, conformal,
Willmore Legendrian immersion in $ S^5$ with constant Willmore dual. As a
corollary, every compact Riemann surface can be conformally immersed in $ \C^2$
as an exact, algebraic Lagrangian surface.


title:
Radial Dunkl Processes : Existence and uniqueness, Hitting time, Beta
  Processes and Random Matrices

abstract:
  We begin with the study of some properties of the radial Dunkl process
associated to a reduced root system $R$. It is shown that this diffusion is the
unique strong solution for all $t \geq 0$ of a SDE with singular drift. Then,
we study $T_0$, the first hitting time of the positive Weyl chamber : we prove,
via stochastic calculus, a result already obtained by Chybiryakov on the
finiteness of $T_0$. The second and new part deals with the law of $T_0$ for
which we compute the tail distribution, as well as some insight via stochastic
calculus on how root systems are connected with eigenvalues of standard
matrix-valued processes. This gives rise to the so-called $\beta$-processes.
The ultraspherical $\beta$-Jacobi case still involves a reduced root system
while the general case is closely connected to a non reduced one. This process
lives in a convex bounded domain known as principal Weyl alcove and the strong
uniqueness result remains valid. The last part deals with the first hitting
time of the alcove's boundary and the semi group density which enables us to
answer some open questions.


title:
Stochastic background of relic scalar gravitational waves from
  scalar-tensor gravity

abstract:
  A stochastic background of relic gravitational waves is achieved by the so
called adiabatically-amplified zero-point fluctuations process derived from
early inflation. In principle, it provides a distinctive spectrum of relic
gravitational waves. In the framework of scalar-tensor gravity, we discuss the
scalar modes of gravitational waves and the primordial production of this
scalar component which is generated beside tensorial one. We discuss also the
upper limit for such a relic scalar component with respect to the WMAP
constraints.


title:
Numerical study of the influence of an applied electrical potential on
  the solidification of a binary metal alloy

abstract:
  In this work we study numerically the influence of a homogeneous electrical
field on the fluid and heat transfer phenomena at macroscale and mesoscale
during unidirectional solidification of a binary metal alloy. The numerical
results showed that a pulse electric discharging applied perpendicularly to the
solidification front leads to a much stronger Joule heating of the liquid phase
in comparison to the solid phase. It was found that on the mesoscopic scale the
electric current density is not homogeneous due to the complex shape of the
dendrite and the difference between electrical conductivities of the solid and
liquid phases. This inhomogeneity of the electrical current density in the
mushy zone leads to the increase of the Joule heating of the dendrite in
comparison to the interdendritic liquid and induces a pinch force
(electromagnetic Lorentz force). The main features of the resulting convection
in the interdendritic liquid are discussed.


title:
Efficient dynamical nuclear polarization in quantum dots: Temperature
  dependence

abstract:
  We investigate in micro-photoluminescence experiments the dynamical nuclear
polarization in individual InGaAs quantum dots. Experiments carried out in an
applied magnetic field of 2T show that the nuclear polarization achieved
through the optical pumping of electron spins is increasing with the sample
temperature between 2K and 55K, reaching a maximum of about 50%. Analysing the
dependence of the Overhauser shift on the spin polarization of the optically
injected electron as a function of temperature enables us to identify the main
reasons for this increase.


title: Quadratic maps between groups

abstract:
  The notion of quadratic maps between arbitrary groups appeared at several
places in the literature on quadratic algebra. Here a unified extensive
treatment of their properties is given; the relation with a relative version of
Passi's polynomial maps and groups of degree 2 is established and used to study
the structure of the latter.


title: Regulators of canonical extensions are torsion: the smooth divisor case

abstract:
  In this paper, we prove a generalization of Reznikov's theorem which says
that the Chern-Simons classes and in particular the Deligne Chern classes (in
degrees $>1$) are torsion, of a flat bundle on a smooth complex projective
variety. We consider the case of a smooth quasi--projective variety with an
irreducible smooth divisor at infinity. We define the Chern-Simons classes of
Deligne's canonical extension of a flat vector bundle with unipotent monodromy
at infinity, which lift the Deligne Chern classes and prove that these classes
are torsion.


title:
Search for invisibly decaying Higgs bosons in e+e- -> Zoho production at
  sqrt(s) = 183 - 209 GeV

abstract:
  A search is performed for Higgs bosons decaying into invisible final states,
produced in association with a Zo boson in e+e- collisions at energies between
183 and 209 GeV. The search is based on data samples collected by the OPAL
detector at LEP corresponding to an integrated luminosity of about 660 pb-1.
The analysis aims to select events containing the hadronic decay products of
the Zo boson and large missing momentum, as expected from Higgs boson decay
into a pair of stable weakly interacting neutral particles, such as the
lightest neutralino in the Minimal Supersymmetric Standard Model. The same
analysis is applied to a search for nearly invisible Higgs boson cascade decays
into stable weakly interacting neutral particles. No excess over the expected
background from Standard Model processes is observed. Limits on the production
of invisibly decaying Higgs bosons produced in association with a Zo boson are
derived. Assuming a branching ratio BR(ho->invisible)=1, a lower limit of 108.2
GeV is placed on the Higgs boson mass at the 95% confidence level. Limits on
the production of nearly invisibly decaying Higgs bosons are also obtained.