title:
Evidence for Two Gaps and Breakdown of the Uemura Plot in
  Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ Single Crystals

abstract:
  We report a detailed investigation on the lower critical field $H_{c1}$ of
the superconducting Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ (FeAs-122) single crystals.
A pronounced kink is observed on the $H_{c1}(T)$ curve, which is attributed to
the existence of two superconducting gaps. By fitting the data $H_{c1}(T)$ to
the two-gap BCS model in full temperature region, a small gap of
$\Delta_a(0)=2.0\pm 0.3$ meV and a large gap of $\Delta_b(0)=8.9\pm 0.4$ meV
are obtained. The in-plane penetration depth $\lambda_{ab}(0)$ is estimated to
be 105 nm corresponding to a rather large superfluid density, which points to
the breakdown of the Uemura plot in FeAs-122 superconductors.


title:
Monotonic d-wave Superconducting Gap in Optimally-Doped
  Bi$_2$Sr$_{1.6}$La$_{0.4}$CuO$_6$ Superconductor by Laser-Based
  Angle-Resolved Photoemission Spectroscopy

abstract:
  The momentum and temperature dependence of the superconducting gap and
pseudogap in optimally-doped Bi$_2$Sr$_{1.6}$La$_{0.4}$CuO$_6$ superconductor
is investigated by super-high resolution laser-based angle-resolved
photoemission spectroscopy. The measured energy gap in the superconducting
state exhibits a standard {\it d}-wave form. Pseudogap opens above T$_c$ over a
large portion of the Fermi surface with a "Fermi arc" formed near the nodal
region. In the region outside of the "Fermi arc", the pseudogap has the similar
magnitude and momentum dependence as the gap in the superconducting state which
changes little with temperature and shows no abrupt change across T$_c$. These
observations indicate that the pseudogap and superconducting gap are closely
related and favor the picture that the pseudogap is a precursor to the
superconducting gap.


title:
Low-energy spectral features of supernova (anti)neutrinos in inverted
  hierarchy

abstract:
  In the dense supernova core, self-interactions may align the flavor
polarization vectors of neutrinos and antineutrinos, and induce collective
flavor transformations. Different alignment ansatzes are known to describe
approximately the phenomena of synchronized or bipolar oscillations, and the
split of neutrino energy spectra. We discuss another phenomenon observed in
some numerical experiments in inverted hierarchy, showing features akin to a
low-energy split of antineutrino spectra. The phenomenon appears to be
approximately described by another alignment ansatz which, in the considered
scenario, reduces the (nonadiabatic) dynamics of all energy modes to only two
neutrino plus two antineutrino modes. The associated spectral features,
however, appear to be fragile when passing from single- to multi-angle
simulations.


title: Jet Modification in Heavy Ion Collisions at RHIC

abstract:
  These proceedings present a brief overview of the main results on
jet-modifications in heavy ion collisions at RHIC. In heavy ion collisions,
jets are studied using single hadron spectra and di-hadron correlations with a
high-\pt{} trigger hadrons. At high pt, a suppression of the yields due to
parton energy loss is observed. A quantitative confrontation of the data with
various theoretical approaches to energy loss in a dense QCD medium is being
pursued. First results from $\gamma$-jet events, where the photon balances the
initial jet energy, are also presented and compared to expectations from models
based on di-hadron measurements. At intermediate pt, two striking modifications
of the di-hadron correlation structure are found in heavy ion collisions: the
presence of a long-range {\it ridge} structure in \deta{}, and a large
broadening of the recoil jet. Both phenomena seem to indicate an interplay
between hard and soft physics.


title: Evolution and nucleosynthesis in low mass Asymptotic Giant Branch stars

abstract:
  People usually smile when astrophysicists assert that we are sons of the
stars, but human life confirms this sentence: about 65% of the mass of our body
is made up of oxygen, carbon occurs in all organic life and is the basis of
organic chemistry, nitrogen is an essential part of amino acids and nucleic
acids, calcium is a major component of our bones. Moreover, phosphorus plays a
major role in biological molecules such as DNA and RNA (where the chemical
codes of life is written) and our blood carries oxygen to tissues by means of
the hemoglobin (an iron pigment of red blood cells). All these elements have
been created in stars. I just list some examples related to human body, but
also common element such as aluminum, nickel, gold, silver and lead come from a
pristine generation of stars. The abundances in the Solar System are in fact
due to the mixing of material ejected from stars that polluted the Universe in
different epochs before the Sun formation, occurred about 5 billion years ago,
after the gravitational contraction of the proto-solar cloud. Low mass AGB
stars (1<M/Msun<3) are among the most important polluters of the Milky Way,
because of the strong winds eroding their chemically enriched envelopes. They
are responsible for the nucleosynthesis of the main component of the cosmic
s-elements.


title: Hyperboloidal evolution with the Einstein equations

abstract:
  We consider an approach to the hyperboloidal evolution problem based on the
Einstein equations written for a rescaled metric. It is shown that a conformal
scale factor can be freely prescribed a priori in terms of coordinates in a
well-posed hyperboloidal initial value problem such that the location of null
infinity is independent of the time coordinate. With an appropriate choice of a
single gauge source function each of the formally singular conformal source
terms in the equations attains a regular limit at null infinity. The suggested
approach could be beneficial in numerical relativity for both wave extraction
and outer boundary treatment.


title: Supersymmetry Breaks when Gauge Symmetry Breaks: Cybersusy I

abstract:
  This paper summarizes a new approach to supersymmetry breaking in the
supersymmetric standard model (SSM). The approach arises from some remarkable
features of the BRS cohomology for composite operators in the SSM, and the
behaviour of those operators when gauge symmetry is spontaneously broken. A new
realization of supersymmetry arises for these operators. This realization is
equivalent to the generation of supersymmetry anomalies, though they are not
present in the usual sense. The consequences are worked out in detail for the
electron and neutrino flavour triplets, by using the appropriate effective
action to analyze the new anomalous realization of supersymmetry. This
effective action generates a mass spectrum for leptons that is consistent with
present experimental data. There is no vacuum energy problem, and no annoying
mass sum rules are present.


title: Theory of the Neutrino Mass

abstract:
  Theoretical aspects of neutrino physics are reviewed, with emphasis on
possible explanations of the smallness of neutrino masses and of the peculiar
mixing pattern observed in the lepton sector. Some theoretically motivated
frameworks, such as those based on spontaneously broken discrete flavour
symmetries, are discussed, stressing the importance of low-energy observables,
like anomalous magnetic moments, electric dipole moments and lepton flavour
violating transitions, to test further features of these models.


title:
RoboNet-II: Follow-up observations of microlensing events with a robotic
  network of telescopes

abstract:
  RoboNet-II uses a global network of robotic telescopes to perform follow-up
observations of microlensing events in the Galactic Bulge. The current network
consists of three 2m telescopes located in Hawaii and Australia (owned by Las
Cumbres Observatory) and the Canary Islands (owned by Liverpool John Moores
University). In future years the network will be expanded by deploying clusters
of 1m telescopes in other suitable locations. A principal scientific aim of the
RoboNet-II project is the detection of cool extra-solar planets by the method
of gravitational microlensing. These detections will provide crucial
constraints to models of planetary formation and orbital migration. RoboNet-II
acts in coordination with the PLANET microlensing follow-up network and uses an
optimization algorithm ("web-PLOP") to select the targets and a distributed
scheduling paradigm (eSTAR) to execute the observations. Continuous automated
assessment of the observations and anomaly detection is provided by the ARTEMiS
system.


title: Axion hot dark matter bounds

abstract:
  We derive cosmological limits on two-component hot dark matter consisting of
neutrinos and axions. We restrict the large-scale structure data to the safely
linear regime, excluding the Lyman-alpha forest. We derive Bayesian credible
regions in the two-parameter space consisting of m_a and sum(m_nu).
Marginalizing over sum(m_nu) provides m_a<1.02 eV (95% CL). In the absence of
axions the same data and methods give sum(m_nu)< 0.63 eV (95% CL).


title: Quantum response to time-dependent external fields

abstract:
  Recently, explicit real time dynamics has been studied in various systems.
These quantum mechanical dynamics could provide new recipes in information
processing. We study quantum dynamics under time dependent external fields, and
explore how to control the quantum state, and also how to bring the state into
a target state. Here, we investigate a pure quantum mechanical dynamics,
dynamics in quantum Monte Carlo simulation and also in quantum master equation.
For the control magnetic states, operators which do not commute with
magnetization are important. We study case of the transverse Ising model, in
which we compare natures of thermal and quantum fluctuations. We also study the
cases of the Dzyaloshinsky-Moriya interaction, where we find a peculiar energy
level structure. Moreover we study the case of itinerant magnetic state, where
we study the change from the Mott insulator to the Nagaoka ferromagnetic state.
Effects of dissipation are also discussed.


title:
Persistent random walk on a one-dimensional lattice with random
  asymmetric transmittances

abstract:
  We study the persistent random walk of photons on a one-dimensional lattice
of random asymmetric transmittances. Each site is characterized by its
intensity transmittance t (t') for photons moving to the right (left)
direction. Transmittances at different sites are assumed independent,
distributed according to a given probability density Distribution. We use the
effective medium approximation and identify two classes of probability density
distribution of transmittances which lead to the normal diffusion of photons.
Monte Carlo simulations confirm our predictions.


title: Stochastic approach for a multivalued Dirichlet-Neumann problem

abstract:
  We prove the existence and uniqueness of a viscosity solution of the
parabolic variational inequality with a nonlinear multivalued Neumann-Dirichlet
boundary condition:% {equation*} \{{array}{r} \dfrac{\partial u(t,x)}{\partial
t}-\mathcal{L}_{t}u(t,x) {+}{% \partial \phi}\big(u(t,x)\big)\ni
f\big(t,x,u(t,x),(\nabla u\sigma)(t,x)\big), t>0, x\in \mathcal{D},\medskip
\multicolumn{1}{l}{\dfrac{\partial u(t,x)}{\partial n}+{\partial \psi}\big(%
u(t,x)\big)\ni g\big(t,x,u(t,x)\big), t>0, x\in
Bd(\mathcal{D}%),\multicolumn{1}{l}{u(0,x)=h(x), x\in \bar{\mathcal{D}},}%
{array}%. {equation*}% where $\partial \phi $ and $\partial \psi $ are
subdifferentials operators and $\mathcal{L}_{t}$ is a second differential
operator. The result is obtained by a Feynman-Ka\c{c} representation formula
starting from the backward stochastic variational inequality:% {equation*}
\{{array}{l} dY_{t}{+}F(t,Y_{t},Z_{t}) dt{+}G(t,Y_{t}) dA_{t}\in \partial \phi
(Y_{t}) dt{+}\partial \psi (Y_{t}) dA_{t}{+}Z_{t}dW_{t}, 0\leq t\leq T,\medskip
\ Y_{T}=\xi .% {array}%. {equation*}


title:
Generalized Elliott-Yafet theory of electron spin relaxation in metals:
  the origin of the anomalous electron spin life-time in MgB2

abstract:
  The temperature dependence of the electron spin relaxation time in MgB2 is
anomalous as it does not follow the temperature dependence of the resistivity
above 150 K, it has a maximum around 400 K, and it decreases for higher
temperatures. This violates the well established Elliot-Yafet theory of
electron spin relaxation in metals. We show that the anomaly occurs when the
quasi-particle scattering rate (in energy units) becomes comparable to the
energy difference between the conduction- and a neighboring band. We find that
the anomalous behavior is related to the unique band structure of MgB$_2$ and
the large electron-phonon coupling. The saturating spin-lattice relaxation can
be regarded as the spin transport analogue of the Ioffe-Regel criterion of
electron transport.


title: A Model Of Inflationary Cosmology Without Singularity

abstract:
  In this letter, we propose a model of inflationary cosmology with a bounce
preceded and study its primordial curvature perturbations. Our model gives rise
to a primordial power spectrum with a feature of oscillation on large scales
compared with the nearly scale-invariant spectrum generated by the traditional
slow rolling inflation model. We will show this effect changes the Cosmic
Microwave Background (CMB) temperature power spectrum and the Large Scale
Structure (LSS) matter power spectrum. And further with a detailed simulation
we will point out this signal is detectable to the forthcoming observations,
such as PLANCK and LAMOST.


title:
Pure emitter dephasing : a resource for advanced solid-state single
  photon sources

abstract:
  We have computed the spectrum emitted spontaneously by a quantum dot coupled
to an arbitrarily detuned single mode cavity, taking into account pure
dephasing processes. We show that if the emitter is incoherent, the cavity can
efficiently emit photons with its own spectral characteristics. This effect
opens unique opportunities for the development of devices exploiting both
cavity quantum electrodynamics effects and pure dephasing, such as wavelength
stabilized single photon sources robust against spectral diffusion.

categories: quant-ph cond-mat.mtrl-sci cond-mat.other physics.atom-ph


title:
Micro-Brillouin Study of the Eigenvibrations of Single Isolated Polymer
  Nanospheres

abstract:
  The localized acoustic modes of single isolated polymethyl methacrylate
(PMMA) and polystyrene nanospheres have been studied by micro-Brillouin light
scattering. The measured mode frequencies are analyzed on the basis of the Lamb
theory formulated for a sphere under free boundary conditions. By measuring
light scattering from single isolated particles, placed atop a piece of
polished silicon wafer, the free-surface conditions are almost experimentally
realized. The observed spectral peaks are attributed to localized
eigenvibrations whose frequencies scale as inverse sphere diameter, in
accordance with Lamb's theory. The Young's moduli and Poisson ratios of the
polymer spheres studied have been evaluated from fits to the experimental data.
We have demonstrated that micro-Brillouin spectroscopy is a powerful technique
for probing the acoustic dynamics and mechanical properties of nanostructures.


title:
Injection to the pick-up ion regime from high energies and induced ion
  power laws

abstract:
  Though pick-up ions (PUIs) are a well known phenomenon in the inner
heliosphere their phase-space distribution nevertheless is a theoretically
unsettled problem. Especially the question of how pick-up ions form their
suprathermal tails, extending to far above their injection energies, still now
is unsatistactorily answered. Though Fermi-2 velocity diffusion theories have
revealed that such tails are populated, they nevertheless show that resulting
population densities are much less than seen in observations showing power-laws
with a velocity index of "-5". We first investigate here, whether or not
observationally suggested power-laws can be the result of a quasi-equilibrium
state between suprathermal ions and magnetohydrodynamic turbulences in energy
exchange with eachother. We demonstrate that such an equilibrium cannot be
established, since it would require too high pick-up ion pressures enforcing a
shock-free deceleration of the solar wind. We furthermore show that Fermi-2
type energy diffusion in the outer heliosphere is too inefficient to determine
the shape of the distribution function there. As we can show, however,
power-laws beyond the injection threshold can be established, if the injection
takes place at higher energies of the order of 100 keV. As we demonstrate here,
such an injection is connected with modulated anomalous cosmic ray (ACR)
particles at the lower end of their spectrum when they again start being
convected outwards with the solar wind. Therefore, we refer to these particles
as ACR-PUIs. In our quantitative calculation of the pick-up ion spectrum
resulting under such conditions we in fact find again power-laws, however with
a velocity power index of "-4" and fairly distance-independent spectral
intensities.


title: Scalar radius of the pion in the Kroll-Lee-Zumino renormalizable theory

abstract:
  The Kroll-Lee-Zumino renormalizable Abelian quantum field theory of pions and
a massive rho-meson is used to calculate the scalar radius of the pion at next
to leading (one loop) order in perturbation theory. Due to renormalizability,
this determination involves no free parameters. The result is $<r^2_\pi>_s =
0.40 {fm}^2$. This value gives for $\bar{\ell}_4$, the low energy constant of
chiral perturbation theory, $\bar{\ell}_4 = 3.4$, and $F_\pi/F = 1.05$, where F
is the pion decay constant in the chiral limit. Given the level of accuracy in
the masses and the $\rho\pi\pi$ coupling, the only sizable uncertainty in this
result is due to the (uncalculated) NNLO contribution.


title:
On the Capability Of Super-Kamiokande Detector To Define the Primary
  Parameters Of Muon And Electron Events

abstract:
  We develop a new discrimination procedure for separating electron neutrinos
from muon neutrinos, based on detailed simulations carried out with GEANT3.21
and with mean angular distribution functions and their relative fluctuations.
Using our procedure we are able to discriminate muons from electrons in Fully
Contained Events in Super-Kamioknade Experiment with a probability of error
ofless than several %. Also we have checked geometrical resolution on both
cases, considering only the ring-like structure of the Cherenkov image and a
geometrical reconstruction procedure utilizing the full distribution. Even the
methodologically correct approach we have adopted, we cannot reproduce the
accuracies for particle discrimination, momentum resolution, interaction vertex
location, and angular resolution obtained by the Super-Kamiokande
Collaboration.


title:
ThermoElectric Transport Properties of a Chain of Quantum Dots with
  Self-Consistent Reservoirs

abstract:
  We introduce a model for charge and heat transport based on the
Landauer-Buttiker scattering approach. The system consists of a chain of $N$
quantum dots, each of them being coupled to a particle reservoir. Additionally,
the left and right ends of the chain are coupled to two particle reservoirs.
All these reservoirs are independent and can be described by any of the
standard physical distributions: Maxwell-Boltzmann, Fermi-Dirac and
Bose-Einstein. In the linear response regime, and under some assumptions, we
first describe the general transport properties of the system. Then we impose
the self-consistency condition, i.e. we fix the boundary values (T_L,\mu_L) and
(T_R,mu_R), and adjust the parameters (T_i,mu_i), for i = 1,...,N, so that the
net average electric and heat currents into all the intermediate reservoirs
vanish. This condition leads to expressions for the temperature and chemical
potential profiles along the system, which turn out to be independent of the
distribution describing the reservoirs. We also determine the average electric
and heat currents flowing through the system and present some numerical
results, using random matrix theory, showing that these currents are typically
governed by Ohm and Fourier laws.

categories: cond-mat.mes-hall cond-mat.stat-mech math-ph math.MP


title:
Aspects of quintessence matter - the driver of the late time
  acceleration of the universe

abstract:
  The present thesis is a collection of papers which deals with analytic models
that can drive the present accelerated expansion of the universe, starting from
a decelerated expansion in the early matter dominated regime. Both minimally
and non minimally coupled scalar fields are employed for the purpose.
Interaction between nonminimally coupled scalar field, such as the Brans-Dicke
field, with dark matter and dark energy are considered. This interactions are
shown to solve some fine tuning problems. Curvature driven acceleration is also
considered in this thesis, which shows that a smooth transition from a
deceleration to an acceleration is possible in this scenario.


title:
A direct measurement of the Bose-Einstein Condensation universality
  class in NiCl$_2$-4SC(NH$_2$)$_2$ at ultra-low temperatures

abstract:
  In this work, we demonstrate field-induced Bose-Einstein condensation (BEC)
in the organic compound NiCl$_2$-4SC(NH$_2$)$_2$ using AC susceptibility
measurements down to 1 mK. The Ni $\textsl{S}$=1 spins exhibit 3D $\mathit{XY}$
antiferromagnetism between a lower critical field $H_{c1} \sim$ 2 T and a upper
critical field $H_{c2} \sim$ 12 T. The results show a power-law temperature
dependence of the phase transition line $H_{c1} (T) -H_{c1} (0) = aT^{\alpha}$
with $\alpha =$ 1.47$\pm$0.10 and $H_{c1} (0) = 2.053$ T, consistent with the
3D Bose-Einstein Condensation universality class. An abnormal change was found
in the phase boundary near $H_{c2}$ at approximately 150 mK.


title: Electrocardiogram of the Mixmaster Universe

abstract:
  The Mixmaster dynamics is revisited in a new light as revealing a series of
transitions in the complex scale invariant scalar invariant of the Weyl
curvature tensor best represented by the speciality index $\mathcal{S}$, which
gives a 4-dimensional measure of the evolution of the spacetime independent of
all the 3-dimensional gauge-dependent variables except for the time used to
parametrize it. Its graph versus time characterized by correlated isolated
pulses in its real and imaginary parts corresponding to curvature wall
collisions serves as a sort of electrocardiogram of the Mixmaster universe,
with each such pulse pair arising from a single circuit or ``complex pulse''
around the origin in the complex plane. These pulses in the speciality index
and their limiting points on the real axis seem to invariantly characterize
some of the so called spike solutions in inhomogeneous cosmology and should
play an important role as a gauge invariant lens through which to view current
investigations of inhomogeneous Mixmaster dynamics.


title: A note on the primordial abundance of stau NLSPs

abstract:
  In scenarios with a gravitino LSP, there exist strong BBN constraints on the
abundance of a possible stau NLSP. We find that in settings with substantial
left-right mixing of the stau mass eigenstates these constraints can be evaded
even for very long-lived staus.


title: Local prediction of turning points of oscillating time series

abstract:
  For oscillating time series, the prediction is often focused on the turning
points. In order to predict the turning point magnitudes and times it is
proposed to form the state space reconstruction only from the turning points
and modify the local (nearest neighbor) model accordingly. The model on turning
points gives optimal prediction at a lower dimensional state space than the
optimal local model applied directly on the oscillating time series and is thus
computationally more efficient. Monte Carlo simulations on different
oscillating nonlinear systems showed that it gives better predictions of
turning points and this is confirmed also for the time series of annual
sunspots and total stress in a plastic deformation experiment.


title: The Mixmaster Universe in a generalized uncertainty principle framework

abstract:
  The Bianchi IX cosmological model is analyzed in a generalized uncertainty
principle framework. The Arnowitt-Deser-Misner reduction of the dynamics is
performed and a time-coordinate, namely the volume of the Universe, naturally
arises. Such a variable is treated in the ordinary way while the anisotropies
(the physical degrees of freedom) are described by a deformed Heisenberg
algebra. The analysis of the model (passing through Bianchi I and II) is
performed at classical level by studying the modifications induced on the
symplectic geometry by the deformed algebra. We show that, the Universe can not
isotropize because of the deformed Kasner dynamics, the triangular allowed
domain is asymptotically stationary with respect to the particle (Universe) and
its bounces against the walls are not interrupted by the deformed effects.
Furthermore, no reflection law can be in general obtained since the Bianchi II
model is no longer analytically integrable. This way, the deformed Mixmaster
Universe can be still considered a chaotic system.


title: Iterated Riesz Commutators: A Simple Proof of Boundedness

abstract:
  We give a simple proof of L^p boundedness of iterated commutators of Riesz
transforms and a product BMO function. We use a representation of the Riesz
transforms by means of simple dyadic operators - dyadic shifts - which in turn
reduces the estimate quickly to paraproduct estimates.


title:
Inclusive diffraction with the ZEUS detector at HERA: a comparison among
  selection methods

abstract:
  The diffractive dissociation of virtual photons, gamma*p -> Xp, has been
studied with the ZEUS detector at HERA by requiring a large rapidity gap
between X and the outgoing proton, by analysing the mass distribution, M_X, of
the hadronic final state, as well as by directly tagging the proton. At low
values of the proton momentum loss, the diffractive structure function
measurements obtained with the three methods are consistent, provided the
different treatment and contributions of proton-dissociative events are taken
into account.


title: Proximity of LaOFeAs to a magnetic instability

abstract:
  We investigate the effect of external pressure on the Fe magnetic moment in
undoped LaOFeAs within the framework of density functional theory and show that
this system is close to a magnetic instability: The Fe moment is found to drop
by nearly a factor of 3 within a pressure range of $\pm$ 5 GPa around the
calculated equilibrium volume. While the Fe moments show an unusually strong
sensitivity to the spin arrangement (type of anti-ferromagnetic structure), the
low temperature structural distortion is found to have only a minor influence
on them. Analysis of the Fermi surface topology and nesting features shows that
these properties change very little up to pressures of at least 10 GPa. We
discuss the magnetic instability in terms of the itinerancy of this system.


title:
Perron-Frobenius operators and representations of the Cuntz-Krieger
  algebras for infinite matrices

abstract:
  In this paper we extend work of Kawamura, see kawamura, for Cuntz-Krieger
algebras O_A for infinite matrices A. We generalize the definition of branching
systems, prove their existence for any given matrix A and show how they induce
some very concrete representations of O_A. We use these representations to
describe the Perron-Frobenius operator, associated to an nonsingular
transformation, as an infinite sum and under some hypothesis we find a matrix
representation for the operator. We finish the paper with a few examples.


title: The Optical Alignment System of the ZEUS MicroVertex Detector

abstract:
  The laser alignment system of the ZEUS microvertex detector is described. The
detector was installed in 2001 as part of an upgrade programme in preparation
for the second phase of electron-proton physics at the HERA collider. The
alignment system monitors the position of the vertex detector support structure
with respect to the central tracking detector using semi-transparent
amorphous-silicon sensors and diode lasers. The system is fully integrated into
the general environmental monitoring of the ZEUS detector and data has been
collected over a period of 5 years. The primary aim of defining periods of
stability for track-based alignment has been achieved and the system is able to
measure movements of the support structure to a precision around $10 \mu$m.


title: On the Integrability of the Discrete Nonlinear Schroedinger Equation

abstract:
  In this letter we present an analytic evidence of the non-integrability of
the discrete nonlinear Schroedinger equation, a well-known discrete evolution
equation which has been obtained in various contexts of physics and biology. We
use a reductive perturbation technique to show an obstruction to its
integrability.


title:
Lattice Dynamics of LaFeAsO_{1-x}F_{x} and PrFeAsO_{1-y} via Inelastic
  X-Ray Scattering and First-Principles Calculation

abstract:
  The lattice dynamics of LaFeAsO_{1-x}F_{x} (x=0, 0.1) and PrFeAsO_{1-y}
(y~0.1) are investigated using inelastic x-ray scattering and ab-initio
calculation. Measurements of powder samples provide an approximation to the
phonon DOS, while dispersion is measured from a single crystal of
PrFeAsO_{1-y}. A model that agrees reasonably well with all of the data at room
temperature is built from results of ab-initio calculations by softening the
strength of the Fe-As bond by 30%.


title: Phantom stars and topology change

abstract:
  In this work, we consider time-dependent dark energy star models, with an
evolving parameter $\omega$ crossing the phantom divide, $\omega=-1$. Once in
the phantom regime, the null energy condition is violated, which physically
implies that the negative radial pressure exceeds the energy density.
Therefore, an enormous negative pressure in the center may, in principle, imply
a topology change, consequently opening up a tunnel and converting the dark
energy star into a wormhole. The criteria for this topology change are
discussed, in particular, we consider the Morse Index analysis and a Casimir
energy approach involving quasi-local energy difference calculations that may
reflect or measure the occurrence of a topology change. We denote these exotic
geometries consisting of dark energy stars (in the phantom regime) and phantom
wormholes as phantom stars. The final product of this topological change,
namely, phantom wormholes, have far-reaching physical and cosmological
implications, as in addition to being used for interstellar shortcuts, an
absurdly advanced civilization may manipulate these geometries to induce closed
timelike curves, consequently violating causality.


title: Resolving Gravitational Singularities

abstract:
  We review recent progress on the resolution of gravitational singularities in
string theory. The main example is the fundamental string in five dimensions
which is singular in the standard supergravity description but regular after
taking into account higher derivative corrections determined by anomalies and
supersymmetry. The application of the AdS/CFT correspondence to geometries that
require higher derivatives for regularity poses interesting challenges.


title: Surface Magnetoelectric Effect in Ferromagnetic Metal Films

abstract:
  A surface magnetoelectric effect is revealed by density-functional
calculations that are applied to ferromagnetic Fe(001), Ni(001) and Co(0001)
films in the presence of external electric field. The effect originates from
spin-dependent screening of the electric field which leads to notable changes
in the surface magnetization and the surface magnetocrystalline anisotropy.
These results are of considerable interest in the area of
electrically-controlled magnetism and magnetoelectric phenomena.


title:
Anomalous WWH couplings in gamma gamma collision with initial beams and
  final state polarizations

abstract:
  The constraints on anomalous Higgs boson couplings are investigated through
the process $\gamma\gamma \to W^{+}W^{-}H$. Considering the longitudinal and
transverse polarization states of the final $W^{+}$ and $W^{-}$ bosons and
incoming beam polarizations, we find 95% confidence level limits on the
anomalous coupling parameters $\Delta a_{W}$, $b_{W}$ and $\beta_{W}$ with an
integrated luminosity of 500 $fb^{-1}$ and $\sqrt{s}$=0.5, 1 TeV energies. We
show that initial beam and final state polarizations lead to a significant
improvement on the sensitivity limits of the anomalous coupling parameters
$b_{W}$ and $\beta_{W}$.


title: Chemical mixing in smoothed particle hydrodynamics simulations

abstract:
  We introduce a simple and efficient algorithm for diffusion in smoothed
particle hydrodynamics (SPH) simulations and apply it to the problem of
chemical mixing. Based on the concept of turbulent diffusion, we link the
diffusivity of a pollutant to the local physical conditions and can thus
resolve mixing in space and time. We apply our prescription to the evolution of
an idealized supernova remnant and find that we can model the distribution of
heavy elements without having to explicitly resolve hydrodynamic instabilities
in the post-shock gas. Instead, the dispersal of the pollutant is implicitly
modelled through its dependence on the local velocity dispersion. Our method
can thus be used in any SPH simulation that investigates chemical mixing but
lacks the necessary resolution on small scales. Potential applications include
the enrichment of the interstellar medium in present-day galaxies, as well as
the intergalactic medium at high redshifts.


title: A Novel Proof of the Heine-Borel Theorem

abstract:
  Every beginning real analysis student learns the classic Heine-Borel theorem,
that the interval [0,1] is compact. In this article, we present a proof of this
result that doesn't involve the standard techniques such as constructing a
sequence and appealing to the completeness of the reals. We put a metric on the
space of infinite binary sequences and prove that compactness of this space
follows from a simple combinatorial lemma. The Heine-Borel theorem is an
immediate corollary.


title: Mutual information is copula entropy

abstract:
  We prove that mutual information is actually negative copula entropy, based
on which a method for mutual information estimation is proposed.


title: The Multiplicity of Main Sequence Turnoffs in Globular Clusters

abstract:
  We present color-magnitude diagrams of globular clusters for models with
self-enrichment and pre-enrichment. The models with self-enrichment turn out to
have two or more main sequence turnoff points in the color-magnitude diagram if
the fraction of mass lost by the globular cluster under supernova explosions
does not exceed 95-97%. The models with pre-enrichment can have only one main
sequence turnoff point. We argue that the cluster wCen evolved according to a
self-enrichment scenario.


abstract:
  An approach to fast fits of the unintegrated gluon density has been developed
and used to determine the unintegrated gluon density by fits to deep inelastic
scatting di-jet data from HERA. The fitting method is based on the
determination of the parameter dependence by help of interpolating between grid
points in the parameter-observable space before the actual fit is performed.


title: Gauge Mediation with Sequestered Supersymmetry Breaking

abstract:
  Gauge mediation models have two drawbacks, that is, the so-called \mu-problem
and a lack of predictability of the gravitino dark matter abundance. We show
that conformal sequestering in the supersymmetry breaking sector offers
attractive solutions to both problems. The correct mass scale of the \mu and
B_\mu terms is generated by taking the gravitino mass of O(100) GeV without
causing the flavor-changing neutral-current problem. Moreover, a large
anomalous dimension of the supersymmetry breaking field naturally realizes the
small stau and neutralino mass difference required for the coannihilation to
work yielding the right dark matter abundance.


title:
Interacting resonant level coupled to a Luttinger liquid: Universality
  of thermodynamic properties

abstract:
  We investigate a model of a single resonant level coupled to the edge of a
quantum wire in the Luttinger liquid phase or to the middle of a chiral
Luttinger liquid via both tunneling and a contact interaction. Utilizing the
Yuval-Anderson approach, we map this model onto a classical 1D Coulomb gas in
which all the details of both the interactions in the lead and the level-lead
interaction enter only through the corresponding Fermi-edge singularity
exponent, which we explicitly evaluate using the Bethe ansatz solution for a
particular model of the lead. Thus the population, dynamical capacitance and
level entropy are universal in the sense of being equal for models with
interactions differing in magnitude and even in sign. We demonstrate this to
hold quantitatively using density matrix renormalization group calculations.
Since the Coulomb gas description is of the single channel Kondo type, we infer
that the universality we found implies that Luttinger liquid physics has no
qualitative effect on these properties, in contrast with perturbative results.


title:
Resonance effects due to the excitation of surface Josephson plasma
  waves in layered superconductors

abstract:
  We analytically examine the excitation of surface Josephson plasma waves
(SJPWs) in periodically-modulated layered superconductors. We show that the
absorption of the incident electromagnetic wave can be substantially increased,
for certain incident angles, due to the resonance excitation of SJPWs. The
absorption increase is accompanied by the decrease of the specular reflection.
Moreover, we find the physical conditions guaranteeing the total absorption
(and total suppression of the specular reflection). These conditions can be
realized for Bi2212 superconductor films.


title: Proof of the Caratheodory Conjecture

abstract:
  A well-known conjecture of Caratheodory states that the number of umbilic
points on a closed convex surface in ${\mathbb E}^3$ must be greater than one.
In this paper we prove this for $C^{3+\alpha}$-smooth surfaces. The Conjecture
is first reformulated in terms of complex points on a Lagrangian surface in
$TS^2$, viewed as the space of oriented geodesics in ${\mathbb E}^3$. Here
complex and Lagrangian refer to the canonical neutral Kaehler structure on
$TS^2$. We then prove that the existence of a closed convex surface with only
one umbilic point implies the existence of a totally real Lagrangian hemisphere
in $TS^2$, to which it is not possible to attach the edge of a holomorphic
disc. The main step in the proof is to establish the existence of a holomorphic
disc with edge contained on any given totally real Lagrangian hemisphere. To
construct the holomorphic disc we utilize mean curvature flow with respect to
the neutral metric. Long-time existence of this flow is proven by a priori
estimates and we show that the flowing disc is asymptotically holomorphic.
Existence of a holomorphic disc is then deduced from Schauder estimates.


title:
Factorizations for 3-rotations and polarization of the light in
  Mueller-Stokes an Jones formalisms

abstract:
  Formulas describing all 2-element and 3-element factorizations of arbitrary
element of the groups SU(2) and SO(3,R) are derived. Six 2-element
factorizations, $ (U_{2}U_{3}U'_{2}), (U_{3}U_{2}U'_{3}), (U_{3}U_{1}U'_{3}),
(U_{1}U_{3}U'_{1}), (U_{1}U_{2}U'_{1}), (U_{2}U_{1}U'_{2})$, provide all
possible way to define Euler type angles; and six 3-element ones, $
(U_{1}U_{2}U_{3}), (U_{1}U_{3}U'_{2}), (U_{2}U_{3}U_{1}), (U_{2}U_{1}U_{3}),
(U_{3}U_{1}U_{2}), (U_{3}U_{2}U_{1})$ provide all possible ways to parameterize
the unitary and orthogonal groups by three elementary angles. In thecontext the
light polarization formalism of Stokes-Mueller vectors and Jones spinors,
relations produced give a base to resolve arbitrary pure polarization rotators
into all possible sets of elementary rotators of two or three constituents.


title: Divergences Test Statistics for Discretely Observed Diffusion Processes

abstract:
  In this paper we propose the use of $\phi$-divergences as test statistics to
verify simple hypotheses about a one-dimensional parametric diffusion process
$\de X_t = b(X_t, \theta)\de t + \sigma(X_t, \theta)\de W_t$, from discrete
observations $\{X_{t_i}, i=0, ..., n\}$ with $t_i = i\Delta_n$, $i=0, 1, >...,
n$, under the asymptotic scheme $\Delta_n\to0$, $n\Delta_n\to\infty$ and
$n\Delta_n^2\to 0$. The class of $\phi$-divergences is wide and includes
several special members like Kullback-Leibler, R\'enyi, power and
$\alpha$-divergences. We derive the asymptotic distribution of the test
statistics based on $\phi$-divergences. The limiting law takes different forms
depending on the regularity of $\phi$. These convergence differ from the
classical results for independent and identically distributed random variables.
Numerical analysis is used to show the small sample properties of the test
statistics in terms of estimated level and power of the test.


title:
Reduction of Almost Poisson brackets and Hamiltonization of the
  Chaplygin Sphere

abstract:
  We construct different almost Poisson brackets for nonholonomic systems than
those existing in the literature and study their reduction. Such brackets are
built by considering non-canonical two-forms on the cotangent bundle of
configuration space and then carrying out a projection onto the constraint
space that encodes the Lagrange-D'Alembert principle. We justify the need for
this type of brackets by working out the reduction of the celebrated Chaplygin
sphere rolling problem. Our construction provides a geometric explanation of
the Hamiltonization of the problem given by A. V. Borisov and I. S. Mamaev.


title: Quantum interference and Klein tunneling in graphene heterojunctions

abstract:
  The observation of quantum conductance oscillations in mesoscopic systems has
traditionally required the confinement of the carriers to a phase space of
reduced dimensionality. While electron optics such as lensing and focusing have
been demonstrated experimentally, building a collimated electron interferometer
in two unconfined dimensions has remained a challenge due to the difficulty of
creating electrostatic barriers that are sharp on the order of the electron
wavelength. Here, we report the observation of conductance oscillations in
extremely narrow graphene heterostructures where a resonant cavity is formed
between two electrostatically created bipolar junctions. Analysis of the
oscillations confirms that p-n junctions have a collimating effect on
ballistically transmitted carriers. The phase shift observed in the conductance
fringes at low magnetic fields is a signature of the perfect transmission of
carriers normally incident on the junctions and thus constitutes a direct
experimental observation of ``Klein Tunneling.''


title: Chiral condensate in neutron matter

abstract:
  A recent chiral perturbation theory calculation of the in-medium quark
condensate $<\bar q q>$ is extended to the isospin-asymmetric case of pure
neutron matter. In contrast to the behavior in isospin-symmetric nuclear matter
we find only small deviations from the linear density approximation. This
feature originates primarily from the reduced weight factors (e.g. 1/6 for the
dominant contributions) of the $2\pi$-exchange mechanisms in pure neutron
matter. Our result suggests therefore that the tendencies for chiral symmetry
restoration are actually favored in systems with large neutron excess (e.g.
neutron stars). We also analyze the behavior of the density-dependent quark
condensate $<\bar q q>(\rho_n)$ in the chiral limit $m_\pi\to 0$.


title:
A Chandra Look at Five of the Broadest Double-Peaked Balmer-Line
  Emitters

abstract:
  We study the 0.5-10keV emission of a sample of five of the broadest
double-peaked Balmer-line emitters with Chandra. The Balmer lines of these
objects originate close (within a few hundred gravitational radii) to the
central black holes of the Active Galactic Nuclei (AGNs), and their
double-peaked profiles suggest an origin in the AGN accretion disk. We find
that four of the five targets can be modeled by simple power-law continua with
photon indices (1.6-1.8) typical of similar luminosity AGNs. One object, SDSS
J0132-0952, shows evidence of ionized intrinsic absorption. The most-luminous
SDSS double-peaked emitter, SDSS J2125-0813, has either an unusual flat
spectrum (~1) or is also highly absorbed. It is the only double-peaked emitter
for which no external illumination is necessary to account for the Balmer line
emission. The strength of the Balmer-line emission in the remaining four
objects suggests that the total line flux likely exceeds the viscous energy
that can be extracted locally from the accretion disk and external illumination
is necessary. All five double-peaked emitters have unusually strong X-ray
emission relative to their UV/optical emission, which is the likely source of
the external illumination necessary for the production of the observed strong
broad lines. On average about 30% of their bolometric luminosities are emitted
between 0.5-10keV. The spectral energy distributions of the five double-peaked
emitters show the big blue bumps characteristic of radiatively efficient
accretion flows. The Balmer line profiles, as well as the optical and X-ray
fluxes of the double-peaked emitters, are highly variable on timescales of
months to years in the AGN rest frame.


title: Jet Production in Polarized pp Collisions at RHIC

abstract:
  The STAR Collaboration has measured the longitudinal double-spin asymmetry
for inclusive jet production in polarized p+p collisions at sqrt{s} = 200 GeV.
The results set significant new constraints on the gluon polarization within
the nucleon. Future measurements of asymmetries for di-jet production will
provide direct access to the momentum dependence of the gluon polarization,
Delta g(x,Q^2).


title:
The Parts Determine the Whole except for n-Qubit
  Greenberger-Horne-Zeilinger States

abstract:
  The generalized n-qubit Greenberger-Horne-Zeilinger (GHZ) states and their
local unitary equivalents are the only pure states of n qubits that are not
uniquely determined (among arbitrary states, pure or mixed) by their reduced
density matrices of n-1 qubits. Thus, the generalized GHZ states are the only
ones containing information at the n-party level.


title:
Phantom Accretion by Black Holes and the Generalized Second Law of
  Thermodynamics

abstract:
  The accretion of a phantom fluid with non-zero chemical potential by black
holes is discussed with basis on the Generalized Second Law of thermodynamics.
For phantom fluids with positive temperature and negative chemical potential we
demonstrate that the accretion process is possible, and that the condition
guaranteeing the positiveness of the phantom fluid entropy coincides with the
one required by Generalized Second Law. In particular, this result provides a
complementary confirmation that cosmological phantom fluids do not need to have
negative temperatures.


title: Strategies for the Characteristic Extraction of Gravitational Waveforms

abstract:
  We develop, test and compare new numerical and geometrical methods for
improving the accuracy of extracting waveforms using characteristic evolution.
The new numerical method involves use of circular boundaries to the
stereographic grid patches which cover the spherical cross-sections of the
outgoing null cones. We show how an angular version of numerical dissipation
can be introduced into the characteristic code to damp the high frequency error
arising form the irregular way the circular patch boundary cuts through the
grid. The new geometric method involves use of the Weyl tensor component
$\Psi_4$ to extract the waveform as opposed to the original approach via the
Bondi news function. We develop the necessary analytic and computational
formula to compute the $O(1/r)$ radiative part of $\Psi_4$ in terms of a
conformally compactified treatment of null infinity. These methods are compared
and calibrated in test problems based upon linearized waves.


title: Four-Wave Mixing in Ultracold Atoms using Intermediate Rydberg States

abstract:
  Ultracold Rb atoms were used to demonstrate non-degenerate four-wave mixing
through a Rydberg state. Continuous 5S-5P-nD two-photon excitation to the
Rydberg state was combined with an nD-6P tuned laser in a phase matched
geometry. The angular dependence, spatial profile, and dependence on detuning
were investigated, showing good agreement with theory. Under optimum conditions
50 percent of the radiation was emitted into the phase-matched direction.


title:
Orthogonal bundles, theta characteristics and the symplectic strange
  duality

abstract:
  A basis for the space of generalized theta functions of level one for the
spin groups, parameterized by the theta characteristics (the even theta
characteristcs for the odd spin groups) on a curve, is shown to be projectively
flat over the moduli space of curves (for Hitchin's connection). The symplectic
strange duality conjecture, conjectured by Beauville is shown to hold for all
curves of genus at least two, by using Abe's proof of the conjecture for
generic curves, and the above monodromy result.


title: A simple class of N=3 gauge/gravity duals

abstract:
  We find the gravity duals to an infinite series of N=3 Chern-Simons quiver
theories. They are AdS_4 x M_7 vacua of M-theory, with M_7 in a certain class
of 3-Sasaki-Einstein manifolds obtained by a quotient construction. The field
theories can be engineered from a brane configuration; their geometry is
summarized by a "hyperKaehler toric fan" that can be read off easily from the
relative angles of the branes. The singularity at the tip of the cone over M_7
is generically not an orbifold. The simplest new manifolds we consider can be
written as the biquotient U(1)\U(3)/U(1). We also comment on the relation
between our theories and four-dimensional N=1 theories with the same quiver.


title:
Pressure-induced electronic mixing and enhancement of ferromagnetic
  ordering in EuX (X=Te, Se, S, O) magnetic semiconductors

abstract:
  The pressure- and anion-dependent electronic structure of EuX (X=Te, Se, S,
O) monochalcogenides is probed with element- and orbital-specific X-ray
absorption spectroscopy in a diamond anvil cell. An isotropic lattice
contraction enhances the ferromagnetic ordering temperature by inducing mixing
of Eu 4{\it f} and 5{\it d} electronic orbitals. Anion substitution (Te $\to$
O) enhances competing exchange pathways through spin-polarized anion {\it p}
states, counteracting the effect of the concomitant lattice contraction. The
results have strong implications for efforts aimed at enhancing FM exchange
interactions in thin films through interfacial strain or chemical
substitutions.


title: Constant-length substitutions and countable scrambled sets

abstract:
  In this paper we provide examples of topological dynamical systems having
either finite or countable scrambled sets. In particular we study conditions
for the existence of Li-Yorke, asymptotic and distal pairs in constant--length
substitution dynamical systems. Starting from a circle rotation we also
construct a dynamical system having Li--Yorke pairs, none of which is
recurrent.


title:
Tracking and physics validation studies of the simplified geometry
  description with $B^0_{(s)} \to h^+h^{'-}$ decays

abstract:
  This note validates the usage of the simplified detector geometry
description. A sample of $B^0_{(s)} \to h^+h^{'-}$ decays was used to assess
the tracking and physics performance with respect to what is obtained with the
full detector description. No significant degradation of performance was found.


title:
Corrigendum and addendum to: Linearly recurrent subshifts have a finite
  number of non-periodic factors

abstract:
  We prove that a subshift $(X,T)$ is linearly recurrent if and only if it is a
primitive and proper $S$-adic subshift. This corrects Proposition 6 in F.
Durand ({\it Ergod. Th. & Dynam. Sys. {\bf 20}} (2000), 1061--1078).


title:
Thermal inertia of main belt asteroids smaller than 100 km from IRAS
  data

abstract:
  Recent works have shown that the thermal inertia of km-sized near-Earth
asteroids (NEAs) is more than two orders of magnitude higher than that of main
belt asteroids (MBAs) with sizes (diameters) between 200 and 1,000 km. This
confirms the idea that large MBAs, over hundreds millions of years,have
developed a fine and thick thermally insulating regolith layer, responsible for
the low values of their thermal inertia, whereas km-sized asteroids, having
collisional lifetimes of only some millions years, have less regolith, and
consequently a larger surface thermal inertia. Because it is believed that
regolith on asteroids forms as a result of impact processes, a better knowledge
of asteroid thermal inertia values and its correlation with size, taxonomic
type, and density can be used as an important constraintfor modeling of impact
processes on asteroids. However, our knowledge of asteroids' thermal inertia
values is still based on few data points with NEAs covering the size range
0.1-20 km and MBAs that >100 km. Here, we use IRAS infrared measurements to
estimate the thermal inertias of MBAs with diameters 100 km and known shapes
and spin vector: filling an important size gap between the largest MBAs and the
km-sized NEAs. An update to the inverse correlation between thermal inertia and
diameter is presented. For some asteroids thermophysical modelling allowed us
to discriminate between the two still possible spin vector solutions derived
from optical lightcurve inversion. This is important for (720) Bohlinia: our
preferred solution was predicted to be the correct one by Vokrouhlicky et al.
(2003, Nature 425, 147) just on theoretical grounds.


title: Some metrics on Teichm\"uller spaces of surfaces of infinite type

abstract:
  Unlike the case of surfaces of topologically finite type, there are several
different Teichm\"uller spaces that are associated to a surface of topological
infinite type. These Teichm\"uller spaces first depend (set-theoretically) on
whether we work in the hyperbolic category or in the conformal category. They
also depend, given the choice of a point of view (hyperbolic or conformal), on
the choice of a distance function on Teichm\"uller space. Examples of distance
functions that appear naturally in the hyperbolic setting are the length
spectrum distance and the bi-Lipschitz distance, and there are other useful
distance functions. The Teichm\"uller spaces also depend on the choice of a
basepoint. The aim of this paper is to present some examples, results and
questions on the Teichm\"uller theory of surfaces of infinite topological type
that do not appear in the setting the Teichm\"uller theory of surfaces of
finite type. In particular, we point out relations and differences between the
various Teichm\"uller spaces associated to a given surface of topological
infinite type.


title:
The Vacuum Structure, Special Relativity Theory and Quantum Mechanics
  Revisited: A Field Theory-No-Geometry Approach

abstract:
  The main fundamental principles characterizing the vacuum field structure are
formulated, the modeling of the related vacuum medium and charged point
particle dynamics by means of devised field theoretic tools are analyzed. The
Maxwell electrodynamic theory is revisited and newly derived from the suggested
vacuum field structure principles, the classical special relativity theory
relationship between the energy and the corresponding point particle mass is
revisited and newly obtained. The Lorentz force expression with respect to
arbitrary non-inertial reference frames is revisited and discussed in detail,
some new interpretations of relations between the special relativity theory and
quantum mechanics are presented. The famous quantum-mechanical Schr\"{o}dinger
type equations for a relativistic point particle in the external potential and
magnetic fields within the quasiclassical approximation as the Planck constant
$\hbar \to 0$ and the light velocity $c\to \infty$ are obtained.


title: Stokes-space formalism for Bragg scattering in a fiber

abstract:
  Optical frequency conversion by four-wave mixing (Bragg scattering) in a
fiber is considered. The evolution of this process can be modeled using the
signal and idler amplitudes, which are complex, or Stokes-like parameters,
which are real. The Stokes-space formalism allows one to visualize power and
phase information simultaneously, and produces a simple evolution equation for
the Stokes parameters.


title: Jet correlations from unintegrated parton distributions

abstract:
  Transverse-momentum dependent parton distributions can be introduced
gauge-invariantly in QCD from high-energy factorization. We discuss Monte Carlo
applications of these distributions to parton showers and jet physics, with a
view to the implications for the Monte Carlo description of complex hadronic
final states with multiple hard scales at the LHC.


title: Vacuum Decay Time in Strong External Fields

abstract:
  We consider dynamics of vacuum decay and particle production in the context
of short pulse laser experiments. We identify and evaluate the invariant
"materialization time," $\tau$, the timescale for the conversion of an
electromagnetic field energy into particles, and we compare to the laser
related time scales.


title:
Squeezed states produced by modulation interaction and phase conjugation
  in fibers

abstract:
  Number-state expansions are derived for the squeezed states produced by
four-wave mixing (modulation interaction and phase conjugation) in fibers.
These expansions are valid for arbitrary pump-induced coupling and
dispersion-induced mismatch coefficients. To illustrate their use, formulas are
derived for the associated field-quadrature and photon-number variances and
correlations.


title: Capacity Regions and Bounds for a Class of Z-interference Channels

abstract:
  We define a class of Z-interference channels for which we obtain a new upper
bound on the capacity region. The bound exploits a technique first introduced
by Korner and Marton. A channel in this class has the property that, for the
transmitter-receiver pair that suffers from interference, the conditional
output entropy at the receiver is invariant with respect to the transmitted
codewords. We compare the new capacity region upper bound with the
Han/Kobayashi achievable rate region for interference channels. This comparison
shows that our bound is tight in some cases, thereby yielding specific points
on the capacity region as well as sum capacity for certain Z-interference
channels. In particular, this result can be used as an alternate method to
obtain sum capacity of Gaussian Z-interference channels. We then apply an
additional restriction on our channel class: the transmitter-receiver pair that
suffers from interference achieves its maximum output entropy with a single
input distribution irrespective of the interference distribution. For these
channels we show that our new capacity region upper bound coincides with the
Han/Kobayashi achievable rate region, which is therefore capacity-achieving. In
particular, for these channels superposition encoding with partial decoding is
shown to be optimal and a single-letter characterization for the capacity
region is obtained.


title:
Local moments and magnetic order in the two-dimensional Anderson-Mott
  transition

abstract:
  We study the role of electronic correlation in a disordered two-dimensional
model by using a variational wave function that can interpolate between
Anderson and Mott insulators. Within this approach, the Anderson-Mott
transition can be described both in the paramagnetic and in the magnetic
sectors. In the latter case, we find evidence for the formation of local
magnetic moments that order before the Mott transition. The charge gap opening
in the Mott insulator is accompanied by the vanishing of the $\lim_{q\to 0}
\overline{< n_q>< n_{-q}>}$ (the bar denoting the impurity average), which is
related to the compressibility fluctuations. The role of a frustrating
(second-neighbor) hopping is also discussed, with a particular emphasis to the
formation of metastable spin-glass states.


title: Ferromagnetism in multi-band Kondo lattice model

abstract:
  The ferromagnetic spin exchange interaction between the itinerant electrons
and localized moments on a periodic lattice, studied within the so-called Kondo
lattice model (KLM), is considered for multiband situation where the hopping
integral is a matrix, in general. The modified RKKY theory, wherein one can map
such a model onto an effective Heisenberg-like system, is extended to a
multi-band case with finite bandwidth and hybridization on a simple cubic
lattice. As an input for the evaluation of the effective exchange integrals,
one requires the multi-band electronic self energy which is taken from an
earlier proposed ansatz. Using the above procedure, we determine the magnetic
properties of the system like Curie temperature while calculating the chemical
potential and magnetization within a self consistent scheme for various values
of system parameters. The results are discussed in detail and the model is
motivated in order to study the electronic, transport and magnetic properties
of real materials like GdN.


title:
Wavelet analysis of non-Gaussian anisotropies from primordial voids in
  simulated maps of the Cosmic Microwave Background

abstract:
  Phase transitions taking place during the inflationary epoch give rise to
bubbles of true vacuum embedded in the false vacuum. These bubbles can imprint
a distinctive signal on the Cosmic Microwave Background (CMB). We evaluate the
feasibility of detecting these signatures with waveletsin CMB maps, such as
those that will be made available by the European Space Agency's (ESA) Planck
mission.


title: Ricci flows, wormholes and critical phenomena

abstract:
  We study the evolution of wormhole geometries under Ricci flow using
numerical methods. Depending on values of initial data parameters, wormhole
throats either pinch off or evolve to a monotonically growing state. The
transition between these two behaviors exhibits a from of critical phenomena
reminiscent of that observed in gravitational collapse. Similar results are
obtained for initial data that describe space bubbles attached to
asymptotically flat regions. Our numerical methods are applicable to
"matter-coupled" Ricci flows derived from conformal invariance in string
theory.


title: Signatures of clumpy dark matter in the global 21 cm background signal

abstract:
  We examine the extent to which the self-annihilation of supersymmetric
neutralino dark matter, as well as light dark matter, influences the rate of
heating, ionisation and Lyman-alpha pumping of interstellar hydrogen and helium
and the extent to which this is manifested in the 21cm global background
signal. We fully consider the enhancements to the annihilation rate from DM
halos and substructures within them. We find that the influence of such
structures can result in significant changes in the differential brightness
temperature. The changes at redsfhits z<25 are likely to be undetectable due to
the presence of the astrophysical signal; however, in the most favourable
cases, deviations in the differential brightness temperature, relative to its
value in the absence of self-annihilating DM, of up to ~20 mK at z=30 can
occur. Thus we conclude that, in order to exclude these models, experiments
measuring the global 21cm signal, such as EDGES and CORE, will need to reduce
the systematics at 50 MHz to below 20 mK.


title:
Free-energy transition in a gas of non-interacting nonlinear
  wave-particles

abstract:
  We investigate the dynamics of a gas of non-interacting particle-like soliton
waves, demonstrating that phase transitions originate from their collective
behavior. This is predicted by solving exactly the nonlinear equations and by
employing methods of the statistical mechanics of chaos. In particular, we show
that a suitable free energy undergoes a metamorphosis as the input excitation
is increased, thereby developing a first order phase transition whose
measurable manifestation is the formation of shock waves. This demonstrates
that even the simplest phase-space dynamics, involving independent (uncoupled)
degrees of freedom, can sustain critical phenomena.


title: Robust 4-manifolds and robust embeddings

abstract:
  A link in the 3-sphere is homotopically trivial, according to Milnor, if its
components bound disjoint maps of disks in the 4-ball. This paper concerns the
question of what spaces give rise to the same class of homotopically trivial
links when used in place of disks in an analogous definition. We show that
there are 4-manifolds for which this property depends on their embedding in the
4-ball. This work is motivated by the A-B slice problem, a reformulation of the
4-dimensional topological surgery conjecture. As a corollary this provides a
new, secondary, obstruction in the A-B slice problem for a certain class of
decompositions of D^4.


title: The Nekrasov Conjecture for Toric Surfaces

abstract:
  The Nekrasov conjecture predicts a relation between the partition function
for N=2 supersymmetric Yang-Mills theory and the Seiberg-Witten prepotential.
For instantons on R^4, the conjecture was proved, independently and using
different methods, by Nekrasov-Okounkov, Nakajima-Yoshioka, and
Braverman-Etingof. We prove a generalized version of the conjecture for
instantons on noncompact toric surfaces.


title:
Electrostatic Background Forces due to Varying Contact Potentials in
  Casimir Experiments

abstract:
  The existence of a monotonic distance dependent contact potential between two
plates in a Casimir experiment leads to an additional electrostatic force that
is significantly different from the case of a constant potential. Such a
varying potential can arise if there is a uniform gradient in the work function
or contact potential across a plate, as opposed to random microscopic
fluctuations associated with patch potentials. A procedure to compensate for
this force is described for the case of an experiment where the electrostatic
force is minimized at each measurement distance by applying a voltage between
the plates. It is noted that the minimizing voltage is not the contact
potential.


title:
Interstellar Krypton Abundances: The Detection of Kiloparsec-scale
  Differences in Galactic Nucleosynthetic History

abstract:
  We present an analysis of Kr I 1236 line measurements from 50 sight lines in
the Hubble Space Telescope Space Telescope Imaging Spectrograph and Goddard
High Resolution Spectrograph data archives that have sufficiently high
resolution and signal-to-noise ratio to permit reliable krypton-to-hydrogen
abundance ratio determinations. The distribution of Kr/H ratios in this sample
is consistent with a single value for the ISM within 5900 pc of the Sun,
log(Kr/H) = -9.02+/-0.02, apart from a rough annulus from between about 600 and
2500 pc distant. The Kr/H ratio toward stars within this annulus is elevated by
approximately 0.11 dex, similar to previously noted elevations of O/H and Cu/H
gas-phase abundances beyond about 800 pc. A significant drop in the gas-phase
N/O ratio in the same region suggests that this is an artifact of
nucleosynthetic history. Since the physical scale of the annulus' inner edge is
comparable to the radius of the Gould Belt and the outer limit of heliocentric
distances where the D/H abundance ratio is highly variable, these phenomena may
be related to the Gould Belt's origins.


title:
Microsupport of tempered solutions of D-Modules associated to smooth
  morphisms

abstract:
  Let $f:X\to Y$ be a smooth morphism of complex analytic manifolds and let $F$
be an $\mathbb{R}$-constructible complex on $Y$. Let $\cal{M}$ be a coherent
$\shd_X$-module. We prove that the microsupport of the solution complex of
$\shm$ in the tempered holomorphic functions $t \shh \text{om} (f^{-1} F,
\sho_X)$, is contained in the 1-characteristic variety of $\cal{M}$ associated
to $f$, and that the microsupport of the solution complex in the tempered
microfunctions $t\mu hom(f^{-1}F, \sho_X)$ is contained in the
1-microcharacteristic variety of the microlocalized of $\shm$ along
$T^*Y\times_Y X$.
  This applies in particular to the complex of solutions of $\shm$ in the sheaf
of distributions holomorphic in the fibers of an arbitrary smooth morphism.


title: Self-organized periodicity of protein clusters in growing bacteria

abstract:
  Chemotaxis receptors in E. coli form clusters at the cell poles and also
laterally along the cell body, and this clustering plays an important role in
signal transduction. Recently, experiments using flourrescence imaging have
shown that, during cell growth, lateral clusters form at positions
approximately periodically spaced along the cell body. In this paper, we
demonstrate within a lattice model that such spatial organization could arise
spontaneously from a stochastic nucleation mechanism. The same mechanism may
explain the recent observation of periodic aggregates of misfolded proteins in
E. coli.

categories: cond-mat.stat-mech cond-mat.soft q-bio.CB q-bio.SC


title:
VERITAS Discovery of >200GeV Gamma-ray Emission from the
  Intermediate-frequency-peaked BL Lac Object W Comae

abstract:
  We report the detection of very high-energy gamma-ray emission from the
intermediate-frequency-peaked BL Lacertae object W Comae (z=0.102) by VERITAS.
The source was observed between January and April 2008. A strong outburst of
gamma-ray emission was measured in the middle of March, lasting for only four
days. The energy spectrum measured during the two highest flare nights is fit
by a power-law and is found to be very steep, with a differential photon
spectral index of Gamma = 3.81 +- 0.35_stat +- 0.34_syst. The integral photon
flux above 200GeV during those two nights corresponds to roughly 9% of the flux
from the Crab Nebula. Quasi-simultaneous Swift observations at X-ray energies
were triggered by the VERITAS observations. The spectral energy distribution of
the flare data can be described by synchrotron-self-Compton (SSC) or
external-Compton (EC) leptonic jet models, with the latter offering a more
natural set of parameters to fit the data.


title: Laplacian spectrum for the nilpotent Kac-Moody Lie algebras

abstract:
  We prove that the maximal nilpotent subalgebra of a Kac-Moody Lie algebra has
an (essentially unique) Euclidean metric with respect to which the Laplace
operator in the chain complex is scalar on each component of a given degree.
Moreover, both the Lie algebra structure and the metric are uniquely determined
by this property.


title: Dynamics of a stretched nonlinear polymer chain

abstract:
  We study the relaxation dynamics of a coarse-grained polymer chain at
different degrees of stretching by both analytical means and numerical
simulations. The macromolecule is modelled as a string of beads, connected by
anharmonic springs, subject to a tensile force applied at the end monomer of
the chain while the other end is fixed at the origin of coordinates. The impact
of bond non-linearity on the relaxation dynamics of the polymer at different
degrees of stretching is treated analytically within the Gaussian
self-consistent approach (GSC) and then compared to simulation results derived
from two different methods: Monte-Carlo (MC) and Molecular Dynamics (MD).
  At low and medium degrees of chain elongation we find good agreement between
GSC predictions and the Monte-Carlo simulations. However, for strongly
stretched chains the MD method, which takes into account inertial effects,
reveals two important aspects of the nonlinear interaction between monomers:
(i) a coupling and energy transfer between the damped, oscillatory normal modes
of the chain, and (ii) the appearance of non-vanishing contributions of a
continuum of frequencies around the characteristic modes in the power spectrum
of the normal mode correlation functions.


title: Electron spin resonance in Kondo systems

abstract:
  We calculate the dynamical spin response of Kondo impurity and Kondo lattice
systems within a semiphenomenological Fermi liquid description, at low
temperatures $T<T_K$, the Kondo temperature, and low magnetic fields $B \ll k_B
T_K/g\mu_B$. Fermi liquid parameters are determined by comparison (i) with
microscopic theory (numerical renormalization group) for the impurity model and
(ii) with experiment for the lattice model. We find in the impurity case that
the true impurity spin resonance has a width of the order of $T_K$ and
disappears altogether if the $g$-factors of impurity spin and conduction
electron spin are equal. However, there is an impurity-induced resonance
contribution at the conduction electron resonance. The latter is broadened by
spin lattice relaxation and is usually unobservable. In contrast, for the
Anderson lattice in the Kondo regime we find a \textit{sharp} ESR resonance
line only slightly shifted from the local resonance and broadened by spin
lattice relaxation, the latter significantly reduced by both the effects of
heavy fermion physics and ferromagnetic fluctuations. We conjecture that our
findings explain the sharp ESR-lines recently observed in several heavy fermion
compounds.


title:
The Landau gauge gluon and ghost propagator in the refined
  Gribov-Zwanziger framework in 3 dimensions

abstract:
  In previous works, we have constructed a refined version of the
Gribov-Zwanziger action in 4 dimensions, by taking into account a novel
dynamical effect. In this paper, we explore the 3-dimensional case. Analogously
as in 4 dimensions, we obtain a ghost propagator behaving like $1/p^2$ in the
infrared, while the gluon propagator reaches a finite nonvanishing value at
zero momentum. Simultaneously, a clear violation of positivity by the gluon
propagator is also found. This behaviour of the propagators turns out be in
agreement with the recent numerical simulations.


title:
On some interpolation theorems for the multipliers of the Cauchy-
  Stiltjes type integrals

abstract:
  In this paper we prove some interpolation theorems for the multipliers of the
Cauchy- Stiltjes type integrals


title:
Temperature and Spatial Dependence of the Superconducting and Pseudogap
  of NdFeAsO0.86F0.14

abstract:
  The discovery of superconductivity with a critical temperature exceeding 55 K
in the iron-oxypnictides and related compounds has quite suddenly given the
community a new set of materials - breaking the tyranny of copper. This new
class of materials raises fundamental questions related to the origin of the
electron pairing in the superconducting state and to the similarity to
superconductivity in the cuprates. Here, we report spatially resolved
measurements using scanning tunneling microscopy/spectroscopy (STM/STS) of the
newly discovered iron-based layered superconductor NdFeAsO0.86F0.14 (Tc = 48 K)
as a function of temperature. The tunneling spectra at 17 K show a suppression
of spectral intensity within +/- 10 meV, indicative of the opening of the
superconducting gap (SG). Below Tc, the sample exhibits two characteristic gaps
- a large one (18 meV) and a small one (9 meV) - existing in different spatial
locations. Both gaps are closed above Tc at the bulk Tc, but only the small gap
can be fitted with a superconducting gap function. This gap displays a BCS -
like order parameter. Above Tc, at the same location where the small gap was
observed, a pseudogap (PG) opens abruptly at a temperature just above Tc and
closes at 120 K. In contrast to the cuprates, the SG and PG have competing
order parameters.


title:
Kinematics and physical properties of Southern interacting galaxies: the
  minor merger AM 2306-721

abstract:
  We present an observational study about the effects of the interactions in
the kinematics, stellar population and abundances of the components of the
galaxy pair AM2306-721. Rotation curves for the main and companion galaxies
were obtained, showing a deprojected velocity amplitude of 175 km/s and 185
km/s, respectively. The interaction between the main and companion galaxies was
modeled using numerical N-body/hydrodynamical simulations, with the result
indicating that the current stage of the merger would be about 250 Myr after
perigalacticum. The spatial variation in the distribution of the stellar
population components in both galaxies was analysed by fitting combinations of
stellar population models of different age groups. The central region of main
galaxy is dominated by an old (5-10 Gyr) population, while significant
contributions from a young (200 Myr) and intermediate (1 Gyr) components are
found in the disk, being enhanced in the direction of the tidal features. The
stellar population of the companion galaxy is overall much younger, being
dominated by components with 1 Gyr or less, quite widely spread over the whole
disk. Spatial profiles of the oxygen abundance were obtained from the a grid of
photoionization models using the R23 line ratio. The disk of the main galaxy
shows a clear radial gradient, while the companion galaxy presents an oxygen
abundance relatively homogeneous across the disk. The absence of an abundance
gradient in the secondary galaxy is interpreted in terms of mixing by gas flows
from the outer parts to the center of the galaxy due to the gravitational
interaction with the more massive primary.


title: The Great Season Climatic Oscillation and the Global Warming

abstract:
  The present earth warming up is often explained by the atmosphere gas
greenhouse effect. This explanation is in contradiction with the thermodynamics
second law. The warming up by greenhouse effect is quite improbable. It is
cloud reflection that gives to the earth s ground its 15 degres C mean
temperature. Since the reflection of the radiation by gases is negligible, the
role of the atmosphere greenhouse gases in the earth warming up by earth
radiation reflection loses its importance. We think that natural climatic
oscillations contribute more to earth climatic disturbances. The oscillation
that we hypothesize to exist has a long period (800 to 1000 years). The glacier
melting and regeneration cycles lead to variations in the cold region ocean
water density and thermal conductibility according to their salinity. These
variations lead one to think about a macro climate oscillating between maximum
hot and minimum cold temperatures. This oscillation is materialized by the
passages of the planet through hot, mild, and cold eras, leading to the great
season climatic oscillation phenomenon (GSCO). Thus, our planet lives four
great seasons a great spring, a great summer, a great winter and a great
autumn/fall, making a great year embracing our four small classical yearly
seasons. The probabilistic character of the parameters that are at the origin
of this climatic oscillation makes the long-term prediction less precise but
the deterministic tendencies and the resonance phenomena give precious
information on our planet climatic future. The present warming up is well
interpreted in the frame of the great season climatic oscillation theory.


title: Ultraluminous X-ray Sources and Their Nebulae

abstract:
  One of the interesting features of Ultraluminous X-ray sources is that many
of them are surrounded by luminous nebulae exhibiting diverse observational
properties. In different cases the nebulae are photoionized or shock-powered.
Generally, the two energy sources appear to coexist. ULX bubble nebulae may be
considered a new class of shock-powered nebulae similar to upscaled versions of
stellar wind bubbles. Their expansion rates support constant energy influx
rather than single powerful events like Hypernova explosions.


title: Placing direct limits on the mass of earth-bound dark matter

abstract:
  We point out that by comparing the total mass (in gravitational units) of the
earth-moon system, as determined by lunar laser ranging, with the sum of the
lunar mass as independently determined by its gravitational action on
satellites or asteroids, and the earth mass, as determined by the LAGEOS
geodetic survey satellite, one can get a direct measure of the mass of
earth-bound dark matter lying between the radius of the moon's orbit and the
geodetic satellite orbit. Current data show that the mass of such earth-bound
dark matter must be less than $4 \times 10^{-9}$ of the earth's mass.


title:
Search for the highly suppressed decays B- -> K+ pi- pi- and B- -> K- K-
  pi+

abstract:
  We report a search for the decays B- -> K+ pi- pi- and B- -> K- K- pi+, which
are highly suppressed in the Standard Model. Using a sample of (467 +/- 5) x
10^6 BBbar pairs collected with the BaBar detector, we do not see any evidence
of these decays and determine 90% confidence level upper limits of BF(B- -> K+
pi- pi-) < 9.5 x 10^-7 and BF(B- -> K- K- pi+) < 1.6 x 10^-7 on the
corresponding branching fractions, including systematic uncertainties.


title: QCD, Tevatron results and LHC prospects

abstract:
  We present a summary of the most recent measurements relevant to Quantum
Chromodynamics (QCD) delivered by the D0 and CDF Tevatron experiments by May
2008. CDF and D0 are moving toward precision measurements of QCD based on data
samples in excess of 1 fb-1. The inclusive jet cross sections have been
extended to forward rapidity regions and measured with unprecedented precision
following improvements in the jet energy calibration. Results on dijet mass
distributions, bbbar dijet production using tracker based triggers, underlying
event in dijet and Drell-Yan samples, inclusive photon and diphoton cross
sections complete the list of measurements included in this paper. Good
agreement with pQCD within errors is observed for jet production measurements.
An improved and consistent theoretical description is needed for photon+jets
processes. Collisions at the LHC are scheduled for early fall 2008, opening an
era of discoveries at the new energy frontier, 5-7 times higher than that of
the Tevatron.


title:
Resonant electronic states and I-V curves of Fe/MgO/Fe(100) tunnel
  junctions

abstract:
  The bias dependence of the tunnel magnetoresistance (TMR) of Fe/MgO/Fe tunnel
junctions is investigated theoretically with a fully self-consistent scheme
that combines the non-equilibrium Green's functions method with density
functional theory. At voltages smaller than 20 mVolt the I-V characteristics
and the TMR are dominated by resonant transport through narrow interface states
in the minority spin-band. In the parallel configuration this contribution is
quenched by a voltage comparable to the energy width of the interface state,
whereas it persists at all voltages in the anti-parallel configuration. At
higher bias the transport is mainly determined by the relative positions of the
$\Delta_1$ band-edges in the two Fe electrodes, which causes a decrease of the
TMR.


title: Nonlocal Modulation of Entangled Photons

abstract:
  We consider ramifications of the use of high speed light modulators to
questions of correlation and measurement of time-energy entangled photons.
Using phase modulators, we find that temporal modulation of one photon of an
entangled pair, as measured by correlation in the frequency domain, may be
negated or enhanced by modulation of the second photon. Using amplitude
modulators we describe a Fourier technique for measurement of biphoton wave
functions with slow detectors.


title: Notes on toric Sasaki-Einstein seven-manifolds and AdS_4/CFT_3

abstract:
  We study the geometry and topology of two infinite families Y^{p,k} of
Sasaki-Einstein seven-manifolds, that are expected to be AdS_4/CFT_3 dual to
families of N=2 superconformal field theories in three dimensions. These
manifolds, labelled by two positive integers p and k, are Lens space bundles
S^3/Z_p over CP^2 and CP^1 x CP^1, respectively. The corresponding Calabi-Yau
cones are toric. We present their toric diagrams and gauged linear sigma model
charges in terms of p and k, and find that the Y^{p,k} manifolds interpolate
between certain orbifolds of the homogeneous spaces S^7, M^{3,2} and Q^{1,1,1}.


title: Supersymmetric isolated horizons in ADS spacetime

abstract:
  We discuss various physical aspects of nonextremal, extremal and
supersymmetric black holes in asymptotically anti-de Sitter (ADS) spacetimes.
Specifically, we discuss how the isolated horizon (IH) framework leads to an
ambiguity-free description of rotating black holes in these spacetimes. We then
apply this framework to investigate the properties of supersymmetric isolated
horizons (SIHs) in four-dimensional N = 2 gauged supergravity. Among other
results we find that they are necessarily extremal, that rotating SIHs must
have non-trivial electromagnetic fields, and that non-rotating SIHs necessarily
have constant curvature horizon cross sections and a magnetic (though not
electric) charge.


title:
Divergent resistance at the Dirac point in graphene: Evidence for a
  transition in a high magnetic field

abstract:
  We have investigated the behavior of the resistance of graphene at the $n=0$
Landau Level in an intense magnetic field $H$. Employing a low-dissipation
technique (with power $P<$3 fW), we find that, at low temperature $T$, the
resistance at the Dirac point $R_0(H)$ undergoes a 1000-fold increase from
$\sim$10 k$\Omega$ to 40 M$\Omega$ within a narrow interval of field. The
abruptness of the increase suggests that a transition to an insulating, ordered
state occurs at the critical field $H_c$. Results from 5 samples show that
$H_c$ depends systematically on the disorder, as measured by the offset gate
voltage $V_0$. Samples with small $V_0$ display a smaller critical field $H_c$.
Empirically, the steep increase in $R_0$ fits acccurately a
Kosterlitz-Thouless-type correlation length over 3 decades. The curves of $R_0$
vs. $T$ at fixed $H$ approach the thermal-activation form with a gap
$\Delta\sim$15 K as $H\to H_c^{-}$, consistent with a field-induced insulating
state.


title:
Berezinskii-Kosterlitz-Thouless transition in trapped
  quasi-two-dimensional Fermi gas near a Feshbach resonance

abstract:
  We study the superfluid transition in a quasi-two-dimensional Fermi gas with
a magnetic field tuning through a Feshbach resonance. Using an effective
two-dimensional Hamiltonian with renormalized interaction between atoms and
dressed molecules, we investigate the Berezinskii-Kosterlitz-Thouless
transition temperature by studying the phase fluctuation effect. We also take
into account the trapping potential in the radial plane, and discuss the number
and superfluid density distributions. These results can be compared to
experimental outcomes for gases prepared in one-dimensional optical lattices.


title:
Systematic Comparison of Jet Energy-Loss Schemes in a realistic
  hydrodynamic medium

abstract:
  We perform a systematic comparison of three different jet energy-loss
approaches. These include the Armesto-Salgado-Wiedemann scheme based on the
approach of Baier-Dokshitzer-Mueller-Peigne-Schiff and Zakharov (BDMPS-Z/ASW),
the Higher Twist approach (HT) and a scheme based on the approach of
Arnold-Moore-Yaffe (AMY). In this comparison, an identical medium evolution
will be utilized for all three approaches: not only does this entail the use of
the same realistic three-dimensional relativistic fluid dynamics (RFD)
simulation, but also includes the use of identical initial parton-distribution
functions and final fragmentation functions. We are, thus, in a unique
position, not only to isolate fundamental differences between the various
approaches, but also to make rigorous calculations for different experimental
measurements using "state of the art" components. All three approaches are
reduced to a version which contains only one free tunable parameter, this is
then related to the well known transport parameter $\hat{q}$. We find that the
parameters of all three calculations can be adjusted to provide a good
description of inclusive data on $R_{AA}$ versus transverse momentum. However,
we do observe slight differences in their predictions for the centrality and
azimuthal angular dependence of $R_{AA}$ vs. $p_T$. We also note that the value
of the transport coefficient $\hat{q}$ in the three approaches to describe the
data differs significantly.


title: Buckling Thin Disks and Ribbons with Non-Euclidean Metrics

abstract:
  I consider the problem of a thin membrane on which a metric has been
prescribed, for example by lithographically controlling the local swelling
properties of a polymer thin film. While any amount of swelling can be
accommodated locally, geometry prohibits the existence of a global strain-free
configuration. To study this geometrical frustration, I introduce a
perturbative approach. I compute the optimal shape of an annular, thin ribbon
as a function of its width. The topological constraint of closing the ribbon
determines a relationship between the mean curvature and number of wrinkles
that prevents a complete relaxation of the compression strain induced by
swelling and buckles the ribbon out of the plane. These results are then
applied to thin, buckled disks, where the expansion works surprisingly well. I
identify a critical radius above which the disk in-plane strain cannot be
relaxed completely.


title:
Toward the AdS/CFT Gravity Dual for High Energy Collisions.
  3.Gravitationally Collapsing Shell and Quasiequilibrium

abstract:
  The equilibration of matter and onset of hydrodynamics can be understood in
the AdS/CFT context as a gravitational collapse process, in which "collision
debris" create a horizon. In this paper we consider the simplest geometry
possible, a flat shell (or membrane) falling in the holographic direction
toward the horizon. The metric is a combination of two well known solutions:
thermal AdS above the shell and pure AdS below, while motion of the shell is
given by the Israel junction condition. Furthermore, when the shell motion can
be considered slow, we were able to solve for two-point functions of all
boundary stress tensor and found that an observer on the boundary sees a very
peculiar $quasiequilibrium$: while the average stress tensor $<T_{\mu\nu>}$
contains the equilibrium plasma energy and pressure at all times, the spectral
densities of the correlators(related with occupation probabilities of the
modes) reveal additional oscillating terms absent in equilibrium. This is
explained by the "echo" phenomenon, a partial return of the field coherence at
certain "echo" times.


title:
A Confirmation of the Strong Clustering of Distant Red Galaxies at 2 < z
  <3

abstract:
  Recent studies have shown that distant red galaxies (DRGs), which dominate
the high-mass end of the galaxy population at z~2.5, are more strongly
clustered than the population of blue star-forming galaxies at similar
redshifts. However these studies have been severely hampered by the small sizes
of fields having deep near-infrared imaging. Here we use the large UKIDSS Ultra
Deep Survey to study the clustering of DRGs. The size and depth of this survey
allows for an unprecedented measurement of the angular clustering of DRGs at
2<z_phot<3 and K<21. The correlation function shows the expected power law
behavior, but with an apparent upturn at theta<~10". We deproject the angular
clustering to infer the spatial correlation length, finding 10.6+-1.6 h^-1 Mpc.
We use the halo occupation distribution framework to demonstrate that the
observed strong clustering of DRGs is not consistent with standard models of
galaxy clustering, confirming previous suggestions that were based on smaller
samples. Inaccurate photometric redshifts could artificially enhance the
observed clustering, however significant systematic redshift errors would be
required to bring the measurements into agreement with the models. Another
possibility is that the underlying assumption that galaxies interact with their
large-scale environment only through halo mass is not valid, and that other
factors drive the evolution of the oldest, most massive galaxies at z~2.


title: Moduli spaces of Chern-Simons quiver gauge theories and AdS_4/CFT_3

abstract:
  We analyse the classical moduli spaces of supersymmetric vacua of 3d N=2
Chern-Simons quiver gauge theories. We show quite generally that the moduli
space of the 3d theory always contains a baryonic branch of a parent 4d N=1
quiver gauge theory, where the 4d baryonic branch is determined by the vector
of 3d Chern-Simons levels. In particular, starting with a 4d quiver theory dual
to a 3-fold singularity, for certain general choices of Chern-Simons levels
this branch of the moduli space of the corresponding 3d theory is a 4-fold
singularity. Our results lead to a simple general method, using existing 4d
techniques, for constructing candidate 3d N=2 superconformal Chern-Simons
quivers with AdS_4 gravity duals. As simple, but non-trivial, examples, we
identify a family of Chern-Simons quiver gauge theories which are candidate
AdS_4/CFT_3 duals to an infinite class of toric Sasaki-Einstein seven-manifolds
with explicit metrics.


title: Electronic Griffiths phase of the d=2 Mott transition

abstract:
  We investigate the effects of disorder within the T=0 Brinkman-Rice (BR)
scenario for the Mott metal-insulator transition (MIT) in two dimensions (2d).
For sufficiently weak disorder the transition retains the Mott character, as
signaled by the vanishing of the local quasiparticles (QP) weights Z_{i} and
strong disorder screening at criticality. In contrast to the behavior in high
dimensions, here the local spatial fluctuations of QP parameters are strongly
enhanced in the critical regime, with a distribution function P(Z) ~
Z^{\alpha-1} and \alpha tends to zero at the transition. This behavior
indicates a robust emergence of an electronic Griffiths phase preceding the
MIT, in a fashion surprisingly reminiscent of the "Infinite Randomness Fixed
Point" scenario for disordered quantum magnets.


title:
Hubble Space Telescope Spectroscopic Observations of the Narrow-Line
  Region in Nearby Low-Luminosity Active Galactic Nuclei

abstract:
  (Abridged) We present STIS observations of 14 nearby low-luminosity active
galactic nuclei, including 13 LINERs and 1 Seyfert, taken at multiple parallel
slit positions centered on the galaxy nuclei and covering the H-alpha spectral
region. For each galaxy, we measure the emission-line velocities, line widths,
and strengths, to map out the inner narrow-line region structure. There is a
wide diversity among the velocity fields: in a few galaxies the gas is clearly
in disk-like rotation, while in other galaxies the gas kinematics appear
chaotic or are dominated by radial flows with multiple velocity components. The
[S II] line ratio indicates a radial stratification in gas density, with a
sharp increase within the inner 10-20 pc, in the majority of the Type 1
objects. We examine how the [N II] 6583 line width varies as a function of
aperture size over a range of spatial scales, extending from scales comparable
to the black hole's sphere of influence to scales dominated by the host
galaxy's bulge. For most galaxies in the sample, we find that the emission-line
velocity dispersion is largest within the black hole's gravitational sphere of
influence, and decreases with increasing aperture size toward values similar to
the bulge stellar velocity dispersion measured within ground-based apertures.
Future dynamical modeling in order to determine black hole masses for a few
objects in this sample may be worthwhile, although disorganized motion will
limit the accuracy of the mass measurements.


title:
Atmospheric Consequences of Cosmic Ray Variability in the Extragalactic
  Shock Model II: Revised ionization levels and their consequences

abstract:
  It has been suggested that galactic shock asymmetry induced by our galaxy's
infall toward the Virgo Cluster may be a source of periodicity in cosmic ray
exposure as the solar system oscillates perpendicular to the galactic plane.
Here we investigate a mechanism by which cosmic rays might affect terrestrial
biodiversity, ionization and dissociation in the atmosphere, resulting in
depletion of ozone and a resulting increase in the dangerous solar UVB flux on
the ground, with an improved ionization background computation averaged over a
massive ensemble (about 7 x 10^5) shower simulations. We study minimal and full
exposure to the postulated extragalactic background. The atmospheric effects
are greater than with our earlier, simplified ionization model. At the lower
end of the range effects are too small to be of serious consequence. At the
upper end of the range, ~6 % global average loss of ozone column density
exceeds that currently experienced due to effects such as accumulated
chlorofluorocarbons. The intensity is less than a nearby supernova or galactic
gamma-ray burst, but the duration would be about 10^6 times longer. Present UVB
enhancement from current ozone depletion ~3% is a documented stress on the
biosphere, but a depletion of the magnitude found at the upper end of our range
would double the global average UVB flux. For estimates at the upper end of the
range of the cosmic ray variability over geologic time, the mechanism of
atmospheric ozone depletion may provide a major biological stress, which could
easily bring about major loss of biodiversity. Future high energy astrophysical
observations will resolve the question of whether such depletion is likely.

categories: astro-ph hep-ph physics.ao-ph physics.geo-ph q-bio.PE


title:
Finite Size Scaling of Classical Long-Ranged Ising Chains and the
  Criticality of Dissipative Quantum Impurity Models

abstract:
  Motivated in part by quantum criticality in dissipative Kondo systems, we
revisit the finite-size scaling of a classical Ising chain with 1/r^{2-epsilon}
interactions. For 1/2<epsilon<1, the scaling of the dynamical spin
susceptibility is sensitive to the degree of "winding" of the interaction under
periodic boundary conditions. Infinite winding yields the expected mean-field
behavior, whereas without any winding the scaling is of an interacting omega/T
form. The contrast with the behavior of the Bose-Fermi Kondo model suggests a
breakdown of a mapping from the quantum model to a classical one due to the
smearing of the Kondo spin flips by the continuum limit taken in this mapping.


title: Langlands Functoriality Conjecture

abstract:
  Functoriality conjecture is one of the central subjects of the present-day
mathematics. Functoriality is the profound problem formulated by Robert
Langlands in the late 1960s in order to establish nonabelian class field
theory. In this expository paper, we describe the Langlands-Shahidi method, the
local and global Langlands conjectures and the converse theorems which are
powerful tools for the establishment of functoriality of some important cases,
and survey the interesting results related to functoriality conjecture.