title: Geometrically Induced Phase Transitions at Large N

abstract:
  Utilizing the large N dual description of a metastable system of branes and
anti-branes wrapping rigid homologous S^2's in a non-compact Calabi-Yau
threefold, we study phase transitions induced by changing the positions of the
S^2's. At leading order in 1/N the effective potential for this system is
computed by the planar limit of an auxiliary matrix model. Beginning at the two
loop correction, the degenerate vacuum energy density of the discrete confining
vacua split, and a potential is generated for the axion. Changing the relative
positions of the S^2's causes discrete jumps in the energetically preferred
confining vacuum and can also obstruct direct brane/anti-brane annihilation
processes. The branes must hop to nearby S^2's before annihilating, thus
significantly increasing the lifetime of the corresponding non-supersymmetric
vacua. We also speculate that misaligned metastable glueball phases may
generate a repulsive inter-brane force which stabilizes the radial mode present
in compact Calabi-Yau threefolds.


title:
Real space information from Fluctuation electron microscopy:
  Applications to amorphous silicon

abstract:
  Ideal models of complex materials must satisfy all available information
about the system. Generally, this information consists of experimental data,
information implicit to sophisticated interatomic interactions and potentially
other {\it a priori} information. By jointly imposing first-principles or
tight-binding information in conjunction with experimental data, we have
developed a method: Experimentally Constrained Molecular Relaxation (ECMR) that
uses {\it all} of the information available. We apply the method to model
medium range order in amorphous silicon using Fluctuation Electron microscopy
(FEM) data as experimental information. The paracrystalline model of medium
range order is examined, and a new model based on voids in amorphous silicon is
proposed. Our work suggests that films of amorphous silicon showing medium
range order (in FEM experiments) can be accurately represented by a continuous
random network model with inhomogeneities consisting of ordered grains and
voids dispersed in the network.


title:
Contributions of Cherenkov Light to the Signals from Lead Tungstate
  Crystals

abstract:
  Results are presented of detailed measurements of the signals generated by
high-energy electrons and muons in lead tungstate crystals. A significant
fraction of the light produced in these crystals and detected by
photomultiplier tubes is the result of the \v{C}erenkov mechanism. This is
concluded from the angular dependence of the signals and from their time
structure. Depending on the orientation of the crystals and on the particle
type, \v{C}erenkov light may account for up to 15% of the total signals.


title: Reversible plasticity in amorphous materials

abstract:
  A fundamental assumption in our understanding of material rheology is that
when microscopic deformations are reversible, the material responds elastically
to external loads. Plasticity, i.e. dissipative and irreversible macroscopic
changes in a material, is assumed to be the consequence of irreversible
microscopic events. Here we show direct evidence for reversible plastic events
at the microscopic scale in both experiments and simulations of two-dimensional
foam. In the simulations, we demonstrate a link between reversible plastic
rearrangement events and pathways in the potential energy landscape of the
system. These findings represent a fundamental change in our understanding of
materials--microscopic reversibility does not necessarily imply elasticity.


title: Supersymmetry and Lie groups

abstract:
  We construct all vacuum states of $\mathcal{N}=2$ supersymmetric Yang-Mills
quantum mechanics (for SU(N) group) and discuss their origin from the SU(N)
real cohomology.


title: Loop Corrections and Naturalness in a Chiral Effective Field Theory

abstract:
  The loop expansion is applied to a chiral effective hadronic lagrangian; with
the techniques of Infrared Regularization, it is possible to separate out the
short-range contributions and to write them as local products of fields that
are already present in our lagrangian. (The appropriate field variables must be
re-defined at each order in loops.) The corresponding parameters implicitly
include short-range effects to all orders in the interaction, so these effects
need not be calculated explicitly. The remaining (long-range) contributions
that must be calculated are nonlocal and resemble those in conventional
nuclear-structure calculations. Nonlinear isoscalar scalar $(\sigma)$ and
vector $(\omega)$ meson interactions are included, which incorporate
many-nucleon forces and nucleon substructure. Calculations are carried out at
the two-loop level to illustrate these techniques at finite nuclear densities
and to verify that the coupling parameters remain natural when fitted to the
empirical properties of equilibrium nuclear matter. Contributions from the
$\omega N$ tensor coupling are also discussed.


title: Casimir forces in a T operator approach

abstract:
  We explore the scattering approach to Casimir forces. Our main tool is the
description of Casimir energy in terms of transition operators, as presented in
Kenneth and Klich, Phys. Rev. Lett. 97, 160401 (2006). We study the convergence
properties of the formula and how to utilize it, together with scattering data
to compute the force. We illustrate the approach by describing the force
between scatterers in 1d and 3d,, and in particular show how it may be applied
in order to study the interaction between two spherical bodies at all
distances.

categories: quant-ph cond-mat.stat-mech hep-th math-ph math.MP


title: Adaptive Multigrid Algorithm for Lattice QCD

abstract:
  We present a new multigrid solver that is suitable for the Dirac operator in
the presence of disordered gauge fields. The key behind the success of the
algorithm is an adaptive projection onto the coarse grids that preserves the
near null space. The resulting algorithm has weak dependence on the gauge
coupling and exhibits very little critical slowing down in the chiral limit.
Results are presented for the Wilson Dirac operator of the 2d U(1) Schwinger
model.


title:
Measurement of the Contribution of Neutrons to Hadron Calorimeter
  Signals

abstract:
  The contributions of neutrons to hadronic signals from the DREAM calorimeter
are measured by analyzing the time structure of these signals. The neutrons,
which mainly originate from the evaporation stage of nuclear breakup in the
hadronic shower development process, contribute through elastic scattering off
protons in the plastic scintillating fibers which provide the $dE/dx$
information in this calorimeter. This contribution is characterized by an
exponential tail in the pulse shape, with a time constant of $\sim 25$ ns. The
relative contribution of neutrons to the signals increases with the distance
from the shower axis. As expected, the neutrons do not contribute to the DREAM
\v{C}erenkov signals.


title: Geometric measures of entanglement and the Schmidt decomposition

abstract:
  In the standard geometric approach to a measure of entanglement of a pure
state, $\sin^2\theta$ is used, where $\theta$ is the angle between the state to
the closest separable state of products of normalized qubit states. We consider
here a generalization of this notion to separable states consisting of products
of unnormalized states of different dimension. In so doing, the entanglement
measure $\sin^2\theta$ is found to have an interpretation as the distance
between the state to the closest separable state. We also find the components
of the closest separable state and its norm have an interpretation in terms of,
respectively, the eigenvectors and eigenvalues of the reduced density matrices
arising in the Schmidt decomposition of the state vector.


title: Dual-Readout Calorimetry with Lead Tungstate Crystals

abstract:
  Results are presented of beam tests in which a small electromagnetic
calorimeter consisting of lead tungstate crystals was exposed to 50 GeV
electrons and pions. This calorimeter was backed up by the DREAM Dual-Readout
calorimeter, which measures the scintillation and \v{C}erenkov light produced
in the shower development, using two different media. The signals from the
crystal calorimeter were analyzed in great detail in an attempt to determine
the contributions from these two types of light to the signals, event by event.
This information makes it possible to eliminate the dominating source of
fluctuations and thus achieve an important improvement in hadronic calorimeter
performance.


title: Cluster Dual Fermion Approach to Nonlocal Correlations

abstract:
  We formulate a general cluster Dual Fermion Approach to nonlocal correlations
in crystals. The scheme allows the treatment of long-range correlations beyond
cluster DMFT and nonlocal effects in realistic calculations of multiorbital
systems. We show that the the simplest approximation exactly corresponds to
free cluster DMFT. We further consider the relation between the two-particle
Green functions in real and dual variables. We apply this approach by
calculating the Green function of the Hubbard model in one dimension starting
from the two-site cluster DMFT solution. The result agrees well with the Green
function obtained from a DMRG calculation.


title:
Influence of the jet opening angle on the derived kinematical parameters
  of blazar jets having uniform and stratified bulk motion

abstract:
  We present analytical modelling of conical relativistic jets, in order to
evaluate the role of the jet opening angle on certain key parameters that are
inferred from VLBI radio observations of blazar nuclear jets. The key
parameters evaluated are the orientation angle (i.e., the viewing angle) of the
jet and the apparent speed and Doppler factor of the radio knots on parsec
scales. Quantitative comparisons are made of the influence of the jet opening
angle on the above parameters of the radio knots, as would be estimated for two
widely discussed variants of relativistic nuclear jets, namely, those having
uniform bulk speed and those in which the bulk Lorentz factor of the flow
decreases with distance from the jet axis (a `spine--sheath' flow). Our
analysis shows that for both types of jet velocity distributions the
expectation value of the jet orientation angle at first falls dramatically with
increases in the (central) jet Lorentz factor, but it levels off at a fraction
of the opening angle for extremely relativistic jets. We also find that the
effective values of the apparent speeds and Doppler factors of the knots always
decline substantially with increasing jet opening angle, but that this effect
is strongest for ultra-relativistic jets with uniform bulk speed. We suggest
that the paucity of highly superluminal parsec-scale radio components in TeV
blazars can be understood if their jets are highly relativistic and, being
intrinsically weaker, somewhat less well collimated, in comparison to the jets
in other blazars.


title: Erlangen Program at Large--2: Inventing a wheel. The parabolic one

abstract:
  We discuss parabolic versions of Euler's identity e^{it}=cos t + i sin t. A
purely algebraic approach based on dual numbers is known to produce a very
trivial relation e^{pt} = 1+pt. Therefore we use a geometric setup of parabolic
rotations to recover the corresponding non-trivial algebraic framework. Our
main tool is Moebius transformations which turn out to be closely related to
induced representations of the group SL(2,R).
  Keywords: complex numbers, dual numbers, double numbers, linear algebra,
invariant, computer algebra, GiNaC


title:
On the Cohomological Derivation of Yang-Mills Theory in the Antifield
  Formalism

abstract:
  We present a brief review of the cohomological solutions of self-coupling
interactions of the fields in the free Yang-Mills theory. All consistent
interactions among the fields have been obtained using the antifield formalism
through several order BRST deformations of the master equation. It is found
that the coupling deformations halt exclusively at the second order, whereas
higher order deformations are obstructed due to non-local interactions. The
results demonstrate the BRST cohomological derivation of the interacting
Yang-Mills theory.


title: Renormalization and black hole entropy in Loop Quantum Gravity

abstract:
  Microscopic state counting for a black hole in Loop Quantum Gravity yields a
result proportional to horizon area, and inversely proportional to Newton's
constant and the Immirzi parameter. It is argued here that before this result
can be compared to the Bekenstein-Hawking entropy of a macroscopic black hole,
the scale dependence of both Newton's constant and the area must be accounted
for. The two entropies could then agree for any value of the Immirzi parameter,
if a certain renormalization property holds.


title: Large Kinetic Power in FRII Radio Jets

abstract:
  We investigate the total kinetic powers (L_{j}) and ages (t_{age}) of
powerful jets of four FR II radio sources (Cygnus A, 3C 223, 3C 284, and 3C
219) by the detail comparison of the dynamical model of expanding cocoons with
observed ones. It is found that these sources have quite large kinetic powers
with the ratio of L_{j} to the Eddington luminosity (L_{Edd}) resides in $0.02
<L_{j}/L_{Edd} <10$. Reflecting the large kinetic powers, we also find that the
total energy stored in the cocoon (E_{c}) exceed the energy derived from the
minimum energy condition (E_{min}): $2< E_{c}/E_{min} <160$. This implies that
a large amount of kinetic power is carried by invisible components such as
thermal leptons (electron and positron) and/or protons.


title:
The Symmetries and Redundancies of Terror: Patterns in the Dark, A study
  of Terrorist Network Strategy and Structure

abstract:
  Although much political capital has been made regarding the war on terrorism,
and while appropriations have gotten underway, there has been a dearth of deep
work on counter-terrorism, and despite massive efforts by the federal
government, most cities and states do not have a robust response system. In
fact, most do not yet have a robust audit system with which to evaluate their
vulnerabilities or their responses. At the federal level there remain many
unresolved problems of coordination. One reason for this is the shift of much
of federal spending on war-fighting in Afghanistan and Iraq. While this
approach has drawn deep and lasting criticism, it is, in fact, in accord with
many principles of both military and corporate strategy. In the following paper
we explore several models of terrorist networks and the implications of both
the models and their substantive conclusions for combating terrorism.


title: Tetrahedron equations and nilpotent subalgebras of U_q(sl_n)

abstract:
  A relation between q-oscillator R-matrix of the tetrahedron equation and
decompositions of Poinkare-Birkhoff-Witt type bases for nilpotent subalgebras
of U_q(sl_n) is observed.


title: Killing spinors on supersymmetric P-branes

abstract:
  A class of p-brane solutions for supersymmetric gravity theories with
negative cosmological constant are proposed and analyzed. The solutions are
purely bosonic and contain a worldsheet and a transverse section. The
classification relays on the number of intrinsic Killing spinors on the
worldsheet and the transverse section. A explicit discussion of the
classification is performed for the four dimensional worldsheet case.


title:
Spin-triplet pairing instability of the spinon Fermi surface in a U(1)
  spin liquid

abstract:
  Recent experiments on the organic compound \kappa-(ET)_2Cu_2(CN)_3 have
provided a promising example of a two dimensional spin liquid state. This phase
is described by a two-dimensional spinon Fermi sea coupled to a U(1) gauge
field. We study Kohn-Luttinger-like pairing instabilities of the spinon Fermi
surface due to singular interaction processes with twice-the-Fermi-momentum
transfer. We find that under certain circumstances the pairing instability
occurs in odd-orbital-angular-momentum/spin-triplet channels. Implications to
experiments are discussed.


title: One-way Hash Function Based on Neural Network

abstract:
  A hash function is constructed based on a three-layer neural network. The
three neuron-layers are used to realize data confusion, diffusion and
compression respectively, and the multi-block hash mode is presented to support
the plaintext with variable length. Theoretical analysis and experimental
results show that this hash function is one-way, with high key sensitivity and
plaintext sensitivity, and secure against birthday attacks or
meet-in-the-middle attacks. Additionally, the neural network's property makes
it practical to realize in a parallel way. These properties make it a suitable
choice for data signature or authentication.


title: Some gradient estimates for a diffusion equation on Riemannian manifolds

abstract:
  In this note we present some gradient estimates for the diffusion equation
$\partial_t u=\Delta u-\nabla \phi \cdot \nabla u $ on Riemannian manifolds,
where $\phi $ is a C^2 function, which generalize estimates of R. Hamilton's
and Qi S. Zhang's on the heat equation.


title: Multiplicative Order of Gauss Periods

abstract:
  We obtain a lower bound on the multiplicative order of Gauss periods which
generate normal bases over finite fields. This bound improves the previous
bound of J. von zur Gathen and I. E. Shparlinski.


title:
Submillimeter Array Observation of the Proto-Planetary Nebula CRL 618 in
  the CO J=6-5 Line

abstract:
  We report on the results of a Submillimeter Array interferometric observation
of the proto-planetary nebula CRL 618 in the 12CO J=6-5 line. With the new
capability of SMA enabling us to use two receivers at a time, we also observed
simultaneously in the 12CO J=2-1 and 13CO J=2-1 lines. The 12CO J=6-5 and 13CO
J=2-1 lines were first interferometrically observed toward CRL 618. The flux of
the high velocity component of the 12CO J=6-5 line is almost fully recovered,
while roughly 80% of the flux of the low velocity component is resolved out.
The low recovery rate suggests that the emission region of the low velocity
component of the 12CO J=6-5 line is largely extended. Continuum emission is
detected both at 230 and 690 GHz. The flux of the 690 GHz continuum emission
seems to be partially resolved out, suggesting dust emission partly
contaminates the 690 GHz continuum flux. The cavity structure, which has been
confirmed in a previous observation in the 12CO J=2-1 line, is not clearly
detected in the 12CO J=6-5 line, and only the south wall of the cavity is
detected. This result suggests that the physical condition of the molecular
envelope of CRL 618 is not exactly axial symmetric.


title: Disrupting Terrorist Networks, a dynamic fitness landscape approach

abstract:
  Over a period of approximately five years, Pankaj Ghemawat of Harvard
Business School and Daniel Levinthal of the Wharton School have been working on
a detailed simulation (producing approximately a million fitness landscape
graphs) in order to determine optimal patterns of decision-making for
corporations. In 2006, we adapted this study, combining it with our own work on
terrorism to examine what would happen if we inverted Ghemawat and Levinthal's
findings and sought to provide disinformation or otherwise interfere with the
communications and decision processes of terrorist organizations in order to
optimize poor decision making and inefficiencies in organizational
coordination, command and control.
  The bulk of this study was then presented at the 2006 annual meeting of the
North American Association for Computation in the Social and Organizational
Sciences. We present here an updated version of that study, emphasizing the
rather counter-intuitive finding that "soft" targets have almost no value and
that unless one can influence key factors, an effort directed at the easy to
reach elements of terrorist organizations may actually be worse than mounting
no effort at all. We conclude with the recommendation that some fundamental
rethinking may be required if the United States is to effectively defend itself
from future terrorist attacks.


title: Feynman Diagrams and Differential Equations

abstract:
  We review in a pedagogical way the method of differential equations for the
evaluation of D-dimensionally regulated Feynman integrals. After dealing with
the general features of the technique, we discuss its application in the
context of one- and two-loop corrections to the photon propagator in QED, by
computing the Vacuum Polarization tensor exactly in D. Finally, we treat two
cases of less trivial differential equations, respectively associated to a
two-loop three-point, and a four-loop two-point integral. These two examples
are the playgrounds for showing more technical aspects about: Laurent expansion
of the differential equations in D (around D=4); the choice of the boundary
conditions; and the link among differential and difference equations for
Feynman integrals.


title:
Dynamic modeling of competing technology designs, pricing and consumer
  dynamics

abstract:
  The modeling of technology succession and new technology adoption includes a
wide array of techniques from complexity theory. In our previous work, we
applied the results of the Windrum-Birchenhall model to technology policy and
technology development strategies. However, as we began to explore the
Windrum-Birchenhall simulation we discovered significant limitations in their
model and felt that a new model was needed which could accommodate simultaneous
macro and micro-level events in order effectively simulate market volatilities.
The following paper discusses the architecture of the new model of
technological succession developed at the Southern New Hampshire University
International Business Modeling Laboratory and explains results from early
simulation runs. We continue to develop this model and expect to have
additional applications and simulation results as our research progresses.


title: Closed conformal Killing-Yano tensor and geodesic integrability

abstract:
  Assuming the existence of a single rank-2 closed conformal Killing-Yano
tensor with a certain symmetry we show that there exist mutually commuting
rank-2 Killing tensors and Killing vectors. We also discuss the condition of
separation of variables for the geodesic Hamilton-Jacobi equations.


title:
Leakage-induced decoherence during single electron spin manipulation in
  a double quantum dot

abstract:
  Coherent single electron spin oscillation in a double quantum dot system
driven by a magnetic electron spin resonance field is studied theoretically
using a Bloch-type rate equation approach. The oscillation frequency and
relaxation time obtained using typical model parameters are consistent with
experiment findings. The dominant decoherence mechanism is identified to be a
leakage current through a Coulomb blockade barrier at a quantum dot during the
spin manipulation. Nuclear field fluctuations which induce a long relaxation
time are found to contribute only negligibly to the decoherence despite an
earlier suggestion.


title: Persistent Current in Two Coupled Rings

abstract:
  We report the solution of the persistent current in two coupled rings in the
presence of external magnetic fluxes. We showed that the magnetic fluxes modify
the global phase of the electronic wave function for multiple connected
geometry formed by the coupled rings. We obtained an exact solution for the
persistent current and investigated the exact solution numerically. For two
large coupled rings with equal fluxes, we found that the persistent current in
the two coupled rings is in fact equal to that in a single ring. This theory
explains the experimental results observed in a line of sixteen coupled rings.
(Phys. Rev. Lett. 86, 3124 (2001).)


title:
The passage time distribution for a birth-and-death chain: Strong
  stationary duality gives a first stochastic proof

abstract:
  A well-known theorem usually attributed to Keilson states that, for an
irreducible continuous-time birth-and-death chain on the nonnegative integers
and any d, the passage time from state 0 to state d is distributed as a sum of
d independent exponential random variables. Until now, no probabilistic proof
of the theorem has been known. In this paper we use the theory of strong
stationary duality to give a stochastic proof of a similar result for
discrete-time birth-and-death chains and geometric random variables, and the
continuous-time result (which can also be given a direct stochastic proof) then
follows immediately. In both cases we link the parameters of the distributions
to eigenvalue information about the chain. We also discuss how the
continuous-time result leads to a proof of the Ray-Knight theorem.
  Intimately related to the passage-time theorem is a theorem of Fill that any
fastest strong stationary time T for an ergodic birth-and-death chain on {0,
>..., d} in continuous time with generator G, started in state 0, is
distributed as a sum of d independent exponential random variables whose rate
parameters are the nonzero eigenvalues of the negative of G. Our approach
yields the first (sample-path) construction of such a T for which individual
such exponentials summing to T can be explicitly identified.


title: Created-by-current states in long Josephson junctions

abstract:
  Critical curves "critical current - external magnetic field" of long
Josephson junctions with inhomogeneity and variable width are studied. We
demonstrate the existence of the regions of magnetic field where some fluxon
states are stable only, if the external current through the junction is
different from zero. Position and size of such regions depend on length of the
junction, its geometry, parameters of inhomogeneity and form of the junction.
The noncentral (left and right) pure fluxon states are appeared in the
inhomogeneous Josephson junction with increase in the junction length. We
demonstrate new bifurcation points with change in width of the inhomogeneity
and amplitude of the Josephson current through the inhomogeneity.


title: Four- and Five-Body Scattering Calculations

abstract:
  We study the five-quark system $uudd{\bar s}$ in the standard
non-relativistic quark model by solving the scattering problem. Using the
Gaussian Expansion Method (GEM), we perform the almost precise multi-quark
calculations by treating a very large five-body modelspace including the NK
scattering channel explicitly. Although a lot of pseudostates (discretized
continuum states) with $J^\pi={1/2}^\pm$ and $J^\pi={3/2}^\pm$ are obtained
within the bound-state approximation, all the states in $1.4-1.85$ GeV in mass
around ${\rm {\rm \Theta}}^+(1540)$ melt into non-resonant continuum states
through the coupling with the NK scattering state in the realistic case, i.e.,
there is no five-quark resonance below 1.85GeV. Instead, we predict a
five-quark resonance state of $J^\pi={1/2}^-$ with the mass of about 1.9GeV and
the width of $\Gamma \simeq$ 2.68MeV. Similar calculation is done for the
four-quark system $c{\bar c}q{\bar q}$ ($q=u,d$) in connection with
X$^0$(3872).


title: Tubular Neighborhoods of Nodal Sets and Diophantine Approximation

abstract:
  We give upper and lower bounds on the volume of a tubular neighborhood of the
nodal set of an eigenfunction of the Laplacian on a real analytic closed
Riemannian manifold M. As an application we consider the question of
approximating points on M by nodal sets, and explore analogy with approximation
by rational numbers.


title: Clifford's theorem for coherent systems

abstract: Final version to appear in Archiv der Mathematik.


title:
A construction of noncontractible simply connected cell-like two
  dimensional Peano continua

abstract:
  Using the topologist sine curve we present a new functorial construction of
cone-like spaces, starting in the category of all path-connected topological
spaces with a base point and continuous maps, and ending in the subcategory of
all simply connected spaces. If one starts by a noncontractible n-dimensional
Peano continuum for any n>0, then our construction yields a simply connected
noncontractible (n + 1)-dimensional cell-like Peano continuum. In particular,
starting with the circle $\mathbb{S}^1$, one gets a noncontractible simply
connected cell-like 2-dimensional Peano continuum.


title:
Theory for Magnetic Anisotropy of Field-Induced Insulator-to-Metal
  Transition in Cubic Kondo Insulator YbB_{12}

abstract:
  Magnetization and energy gap of Kondo insulator YbB_{12} are calculated
theoretically based on the previously proposed tight-binding model composed of
Yb 5d$\epsilon$ and 4f $\Gamma_8$ orbitals. It is found that magnetization
curves are almost isotropic, naturally expected from the cubic symmetry, but
that the gap-closing field has an anisotropy: the gap closes faster for the
field in (100) direction than in (110) and (111) directions, in accord with the
experiments. This is qualitatively understood by considering the maximal
eigenvalues of the total angular momentum operators projected on each direction
of the magnetic field. But the numerical calculation based on the band model
yields better agreement with the experiment.


title: A Dark Energy Model Characterized by the Age of the Universe

abstract:
  Quantum mechanics together with general relativity leads to the
  K\'arolyh\'azy relation and a corresponding energy density of quantum
fluctuations of space-time. Based on the energy density we propose a dark
energy model, in which the age of the universe is introduced as the length
measure. This dark energy is consistent with astronomical data if the unique
numerical parameter in the dark energy model is taken to be a number of order
one. The dark energy behaves like a cosmological constant at early time and
drives the universe to an eternally accelerated expansion with power-law form
at late time. In addition, we point out a subtlety in this kind of dark energy
model.


title: A universal property for the Jiang-Su algebra

abstract:
  We prove that the infinite tensor power of a unital separable C*-algebra
absorbs the Jiang-Su algebra Z tensorially if and only if it contains,
unitally, a subhomogeneous algebra without characters. This yields a succinct
universal property for Z in a category so large that there are no unital
separable C*-algebras without characters known to lie outside it. This category
moreover contains the vast majority of our stock-in-trade separable amenable
C*-algebras, and is closed under passage to separable superalgebras and
quotients, and hence to unital tensor products, unital direct limits, and
crossed products by countable discrete groups.
  One consequence of our main result is that strongly self-absorbing ASH
algebras are Z-stable, and therefore satisfy the hypotheses of a recent
classification theorem of W. Winter. One concludes that Z is the only
projectionless strongly self-absorbing ASH algebra, completing the
classification of strongly self-absorbing ASH algebras.


title: Zero delay synchronization of chaos in coupled map lattices

abstract:
  We show that two coupled map lattices that are mutually coupled to one
another with a delay can display zero delay synchronization if they are driven
by a third coupled map lattice. We analytically estimate the parametric regimes
that lead to synchronization and show that the presence of mutual delays
enhances synchronization to some extent. The zero delay or isochronal
synchronization is reasonably robust against mismatches in the internal
parameters of the coupled map lattices and we analytically estimate the
synchronization error bounds.


title: Interacting Agegraphic Dark Energy

abstract:
  A new dark energy model, named "agegraphic dark energy", has been proposed
recently, based on the so-called K\'{a}rolyh\'{a}zy uncertainty relation, which
arises from quantum mechanics together with general relativity. In this note,
we extend the original agegraphic dark energy model by including the
interaction between agegraphic dark energy and pressureless (dark) matter. In
the interacting agegraphic dark energy model, there are many interesting
features different from the original agegraphic dark energy model and
holographic dark energy model. The similarity and difference between agegraphic
dark energy and holographic dark energy are also discussed.


title: Microlensing optical depth as a function of source apparent magnitude

abstract:
  Measurements of the microlensing optical depth, tau, towards the Galactic
bulge appear to depend on the method used to obtain them. Those values based on
the lensing of red clump giants (RCGs) appear to be significantly lower than
those based on the lensing of all stars along the line of sight. This
discrepancy is still not understood. Through Monte Carlo simulations, it is
found that the discrepancy cannot be explained by a dependance on the flux
limits of the two methods. The optical depth is expected to be generally
constant as a function of source apparent magnitude for I_0 >~ 13.0, except in
the range 13.5 <~ I_0 <~ 15.5. Here many RCGs are detected, causing a
significant oscillation in tau. The amplitude of this oscillation is a function
of the inclination angle of the Galactic bar, theta_bar, which may thus be
constrained. A further constraint comes from a similar dependance of tau with
theta_bar: combining the predicted trends with the measured values provides
1-sigma upper limits, which exclude the large bar angles recently reported by
the GLIMPSE and EROS surveys. The latest survey data from EROS-2 appear to show
the predicted tau oscillation, though currently at a low significance. However,
a further sign comes from EROS-2 event counts, which show a clear skew towards
fainter magnitudes.


title:
Deformations of Lie algebras of vector fields arising from families of
  schemes

abstract:
  Fialowski and Schlichenmaier constructed examples of global deformations of
Lie algebras of vector fields from deforming the underlying variety. We
formulate their approach in a conceptual way. Namely, we construct a stack of
deformations and a morphism form the moduli stack of stable marked curves. The
morphism associates to a family of marked curves the family of Lie algebras
obtained by taking the Lie algebra of vertical vector fields on the family
where one has extracted the marked points. We show that this morphism is almost
a monomorphism by Pursell-Shanks theory.


title: Photo-induced precession of magnetization in ferromagnetic (Ga,Mn)As

abstract:
  Precession of magnetization induced by pulsed optical excitation is observed
in a ferromagnetic semiconductor (Ga,Mn)As by time-resolved magneto-optical
measurements. It appears as complicated oscillations of polarization plane of
linearly-polarized probe pulses, but is reproduced by gyromagnetic theory
incorporating an impulsive change in an effective magnetic field due to changes
in magnetic anisotropy. It is inferred from the shape of the impulse that the
changes in anisotropy result from non-equilibrium carrier population: cooling
of hot photo-carriers and subsequent annihilation of photo-carriers.


title: Inclusive Charm Production in Upsilon(nS) Decay

abstract:
  Based on the NRQCD factorization formalism, we calculate the inclusive charm
production rate in Upsilon(nS) decay at leading order in the strong coupling
constant alpha_s and the relative velocity v of the b quark in the quarkonium
rest frame. The branching fractions for Upsilon(nS) to charm for n=1, 2, and 3
are all around 7-9%. About 60% of the branching fraction into charm is from
annihilation of the color-singlet bb-bar pair into gamma^* -> cc-bar. Most of
the remaining branching fraction is from annihilation of the color-singlet
bb-bar pair decaying into cc-bar gg. We also compute the momentum distributions
of the charm quark and charmed hadrons in the decays. The virtual-photon
contribution to the charm quark momentum distribution is concentrated at the
end point while the cc-bar gg contribution is broad. The momentum distributions
for charmed hadrons are obtained by convolving the charm-quark momentum
distribution with charm fragmentation functions. This makes the momentum
distributions for charmed hadrons softer than that for the charm quark. This
effect is particularly significant in the virtual-photon contribution.


title:
Inclusive Jet Production in DIS at High Q^2 and Extraction of the Strong
  Coupling

abstract:
  Inclusive jet production is studied in neutral current deep-inelastic
positron-proton scattering at large four momentum transfer squared Q^2>150
GeV^2 with the H1 detector at HERA. The measurements are found to be well
described by calculations at next-to-leading order in perturbative QCD.
  The running of the strong coupling is demonstrated and the value of
alpha_s(M_Z) is determined.


title: Low energy effects of neutrino masses

abstract:
  While all models of Majorana neutrino masses lead to the same dimension five
effective operator, which does not conserve lepton number, the dimension six
operators induced at low energies conserve lepton number and differ depending
on the high energy model of new physics. We derive the low-energy dimension six
operators which are characteristic of generic Seesaw models, in which neutrino
masses result from the exchange of heavy fields which may be either fermionic
singlets, fermionic triplets or scalar triplets. The resulting operators may
lead to effects observable in the near future, if the coefficients of the
dimension five and six operators are decoupled along a certain pattern, which
turns out to be common to all models. The phenomenological consequences are
explored as well, including their contributions to $\mu \to e \gamma$ and new
bounds on the Yukawa couplings for each model.


title:
Summary of H1 Results on the Strong Coupling from Inclusive and Final
  States

abstract:
  Several determinations of the strong coupling from the H1 Collaboration are
reviewed.


title:
Detection of warm molecular hydrogen in the circumstellar disk around
  the Herbig Ae star HD97048

abstract:
  We present high resolution spectroscopic mid-infrared observations of the
circumstellar disk around the Herbig Ae star HD97048 with the VLT Imager and
Spectrometer for the mid-InfraRed (VISIR). We detect the S(1) pure rotational
line of molecular hydrogen (H2) at 17.035 microns arising from the disk around
the star. This detection reinforces the claim that HD97048 is a young object
surrounded by a flared disk at an early stage of evolution. The emitting warm
gas is located within the inner 35 AU of the disk. The line-to-continuum flux
ratio is much higher than expected from models of disks at local thermodynamics
equilibrium. We investigate the possible physical conditions, such as a
gas-to-dust mass ratio higher than 100 and different excitation mechanisms of
molecular hydrogen (X-ray heating, shocks, ...) in order to explain the
detection. We tentatively estimate the mass of warm gas to be in the range from
0.01 to nearly 1 Jupiter Mass. Further observations are needed to better
constrain the excitation mechanisms as well as the mass of gas.


title:
Generation of mesoscopic superpositions of a binary Bose-Einstein
  condensate in a slightly asymmetric double well

abstract:
  A previous publication [Europhysics Letters 78, 10009 (2007)] suggested to
coherently generate mesoscopic superpositions of a two-component Bose-Einstein
condensate in a double well under perfectly symmetric conditions. However,
already tiny asymmetries can destroy the entanglement properties of the ground
state. Nevertheless, even under more realistic conditions, the scheme is
demonstrated numerically to generate mesoscopic superpositions.


title: Quantum suppression of chaotic tunneling

abstract:
  The interplay between chaotic tunneling and dynamical localization in mixed
phase space is investigated. Semiclassical analysis using complex classical
orbits reveals that tunneling through torus regions and transport in chaotic
regions are not independent processes, rather they are strongly correlated and
described by complex orbits with both properties. This predicts a phenomenon
analogous to the quantum suppression of classical diffusion: chaotic tunneling
is suppressed as a result of dynamical localization in chaotic regions. This
hypothesis is confirmed by numerical experiments where the effect of
destructive interference is attenuated.


title:
On classical and pseudobulges: The nature of bulges of early-type
  spirals

abstract:
  Historically, galactic bulges are thought to be elliptical galaxy-like
objects sitting in the middle of a generally larger disk. There are, however,
more and more claims that some bulges are much more similar to disks. John
Kormendy has named these bulges pseudo-bulges. In this paper I discuss some
recent integral field spectroscopy of the SAURON collaboration on a sample of
24 Sa and Sab galaxies. Using their 2-dimensional maps of the stellar velocity,
velocity dispersion, and absorption line strength, it is now much easier to
understand the nature of nearby galactic bulges. I review several aspects of
bulges, namely the surface photometry, stellar kinematics, stellar populations,
presence of interstellar matter, and their behavior in the fundamental plane of
early-type galaxies.


title: Local Leaders in Random Networks

abstract:
  We consider local leaders in random uncorrelated networks, i.e. nodes whose
degree is higher or equal than the degree of all of their neighbors. An
analytical expression is found for the probability of a node of degree $k$ to
be a local leader. This quantity is shown to exhibit a transition from a
situation where high degree nodes are local leaders to a situation where they
are not when the tail of the degree distribution behaves like the power-law
$\sim k^{-\gamma_c}$ with $\gamma_c=3$. Theoretical results are verified by
computer simulations and the importance of finite-size effects is discussed.


title:
C IV absorption in damped and sub-damped Lyman-alpha systems:
  correlations with metallicity and implications for galactic winds at z~2-3

abstract:
  We present a study of C IV absorption in a sample of 63 damped Lyman-alpha
(DLA) systems and 11 sub-DLAs in the redshift range 1.75<z_abs<3.61, using a
dataset of high-resolution (6.6 km/s FWHM), high signal-to-noise VLT/UVES
spectra. Narrow and broad C IV absorption line components indicate the presence
of both warm, photoionized and hot, collisionally ionized gas. We report new
correlations between the metallicity (measured in the neutral-phase) and each
of the C IV column density, the C IV total line width, and the maximum C IV
velocity. We explore the effect on these correlations of the sub-DLAs, the
proximate DLAs (defined as those within 5 000 km/s of the quasar), the
saturated absorbers, and the metal line used to measure the metallicity, and we
find the correlations to be robust. There is no evidence for any difference
between the measured properties of DLA C IV and sub-DLA C IV. In 25 DLAs and 4
sub-DLAs, covering 2.5 dex in [Z/H], we directly observe C IV moving above the
escape speed, where v_esc is derived from the total line width of the neutral
gas profiles. These high-velocity C IV clouds, unbound from the central
potential well, can be interpreted as highly ionized outflowing winds, which
are predicted by numerical simulations of galaxy feedback. The distribution of
C IV column density in DLAs and sub-DLAs is similar to the distribution in
Lyman Break galaxies, where winds are directly observed, supporting the idea
that supernova feedback creates the ionized gas in DLAs. The unbound C IV
absorbers show a median mass flow rate of ~22(r/40 kpc) solar masses per year,
where r is the characteristic C IV radius. Their kinetic energy fluxes are
large enough that a star formation rate (SFR) of ~2 solar masses per year is
required to power them.


title:
Fulde-Ferrell-Larkin-Ovchinnikov states in one-dimensional
  spin-polarized ultracold atomic Fermi gases

abstract:
  We present a systematic study of quantum phases in a one-dimensional
spin-polarized Fermi gas. Three comparative theoretical methods are used to
explore the phase diagram at zero temperature: the mean-field theory with
either an order parameter in a single-plane-wave form or a self-consistently
determined order parameter using the Bogoliubov-de Gennes equations, as well as
the exact soluble Bethe ansatz method. We find that a spatially inhomogeneous
Fulde-Ferrell-Larkin-Ovchinnikov phase, which lies between the fully paired BCS
state and the fully polarized normal state, dominates most of the phase diagram
of a uniform gas. The phase transition from the BCS state to the
Fulde-Ferrell-Larkin-Ovchinnikov phase is of second order, and therefore there
are no phase separation states in one-dimensional homogeneous polarized gases.
This is in sharp contrast to the three-dimensional situation, where a phase
separation regime is predicted to occupy a very large space in the phase
diagram. We conjecture that the prediction of the dominance of the phase
separation phases in three dimension could be an artifact of the
non-self-consistent mean-field approximation, which is heavily used in the
study of three-dimensional polarized Fermi gases. We consider also the effect
of a harmonic trapping potential on the phase diagram, and find that in this
case the trap generally leads to phase separation, in accord with the
experimental observations for a trapped gas in three dimension. We finally
investigate the local fermionic density of states of the
Fulde-Ferrell-Larkin-Ovchinnikov ansatz. A two-energy-gap structure is shown
up, which could be used as an experimental probe of the
Fulde-Ferrell-Larkin-Ovchinnikov states.


title:
The Equation of State of Dense Matter : from Nuclear Collisions to
  Neutron Stars

abstract:
  The Equation of State (EoS) of dense matter represents a central issue in the
study of compact astrophysical objects and heavy ion reactions at intermediate
and relativistic energies. We have derived a nuclear EoS with nucleons and
hyperons within the Brueckner-Hartree-Fock approach, and joined it with quark
matter EoS. For that, we have employed the MIT bag model, as well as the
Nambu--Jona-Lasinio (NJL) and the Color Dielectric (CD) models, and found that
the NS maximum masses are not larger than 1.7 solar masses. A comparison with
available data supports the idea that dense matter EoS should be soft at low
density and quite stiff at high density.


title:
Experimental macroscopic coherence by phase-covariant cloning of a
  single photon

abstract:
  We investigate the multiphoton states generated by high-gain optical
parametric amplification of a single injected photon, polarization encoded as a
''qubit''. The experiment configuration exploits the optimal phase-covariant
cloning in the high gain regime. The interference fringe pattern showing the
non local transfer of coherence between the injected qubit and the mesoscopic
amplified output field involving up to 4000 photons has been investigated. A
probabilistic new method to extract full information about the multiparticle
output wavefunction has been implemented.


title: Atomic cluster state build up with macroscopic heralding

abstract:
  We describe a measurement-based state preparation scheme for the efficient
build up of cluster states in atom-cavity systems. As in a recent proposal for
the generation of maximally entangled atom pairs [Metz et al., Phys. Rev. Lett.
97, 040503 (2006)], we use an electron shelving technique to avoid the
necessity for the detection of single photons. Instead, the successful fusion
of smaller into larger clusters is heralded by an easy-to-detect macroscopic
fluorescence signal. High fidelities are achieved even in the vicinity of the
bad cavity limit and are essentially independent of the concrete size of the
system parameters.


title: Gauged Discrete Symmetries and Proton Stability

abstract:
  We discuss the results of a search for anomaly free Abelian Z_N discrete
symmetries that lead to automatic R-parity conservation and prevents dangerous
higher-dimensional proton decay operators in simple extensions of the minimal
supersymmetric extension of the standard model (MSSM) based on the left-right
symmetric group, the Pati-Salam group and SO(10). We require that the
superpotential for the models have enough structures to be able to give correct
symmetry breaking to MSSM and potentially realistic fermion masses. We find
viable models in each of the extensions and for all the cases, anomaly freedom
of the discrete symmetry restricts the number of generations.


title: Dynamic heterogeneities in attractive colloids

abstract:
  We study the formation of a colloidal gel by means of Molecular Dynamics
simulations of a model for colloidal suspensions. A slowing down with gel-like
features is observed at low temperatures and low volume fractions, due to the
formation of persistent structures. We show that at low volume fraction the
dynamic susceptibility, which describes dynamic heterogeneities, exhibits a
large plateau, dominated by clusters of long living bonds. At higher volume
fraction, where the effect of the crowding of the particles starts to be
present, it crosses over towards a regime characterized by a peak. We introduce
a suitable mean cluster size of clusters of monomers connected by "persistent"
bonds which well describes the dynamic susceptibility.


title: Families of dendrograms

abstract:
  A conceptual framework for cluster analysis from the viewpoint of p-adic
geometry is introduced by describing the space of all dendrograms for n
datapoints and relating it to the moduli space of p-adic Riemannian spheres
with punctures using a method recently applied by Murtagh (2004b). This method
embeds a dendrogram as a subtree into the Bruhat-Tits tree associated to the
p-adic numbers, and goes back to Cornelissen et al. (2001) in p-adic geometry.
After explaining the definitions, the concept of classifiers is discussed in
the context of moduli spaces, and upper bounds for the number of hidden
vertices in dendrograms are given.


title: Constraints on extremal self-dual CFTs

abstract:
  We argue that the existence of a modular differential equation implies that a
certain vector vanishes in Zhu's C2 quotient space, and we check this assertion
in numerous examples. If this connection is true in general, it would imply
that the recently conjectured extremal self-dual conformal field theories at
c=24 k cannot exist for k\geq 42.


title: Suzaku Spectroscopy of the Extended X-Ray Emission in M17

abstract:
  We present the results of a Suzaku spectroscopic study of the soft extended
X-ray emission in the HII region M17. The spectrum of the extended emission was
obtained with a high signal-to-noise ratio in a spatially-resolved manner using
the X-ray Imaging Spectrometer (XIS). We established that the contamination by
unresolved point sources, the Galactic Ridge X-ray emission, the cosmic X-ray
background, and the local hot bubble emission is negligible in the
background-subtracted XIS spectrum of the diffuse emission. Half a dozen of
emission lines were resolved clearly for the first time, including K lines of
highly ionized O, Ne, and Mg as well as L series complex of Fe at 0.5--1.5 keV.
Based on the diagnosis of these lines, we obtained the following results: (1)
the extended emission is an optically-thin thermal plasma represented well by a
single temperature of 3.0 +/- 0.4 MK, (2) the abundances of elements with
emission lines in the diffuse spectrum are 0.1--0.3 solar, while those of
bright discrete sources are 0.3--1.5 solar, (3) the metal abundances relative
to each other in the diffuse emission are consistent with solar except for a Ne
enhancement of a factor of 2, (4) both the plasma temperature and the chemical
composition of the diffuse emission show no spatial variation across the
studied spatial scale of about 5 pc.


title: Statistical hadronization model predictions for charmed hadrons at LHC

abstract:
  We present predictions of the statistical hadronization model for charmed
hadrons production in Pb+Pb collisions at LHC.


title: Thermal model predictions of hadron ratios at LHC

abstract:
  We present predictions of the thermal model for hadron ratios in central
Pb+Pb collisions at LHC.


title: The Polarised Valence Quark Distribution from semi-inclusive DIS

abstract:
  The semi-inclusive difference asymmetry A^{h^{+}-h^{-}} for hadrons of
opposite charge has been measured by the COMPASS experiment at CERN. The data
were collected in the years 2002-2004 using a 160 GeV polarised muon beam
scattered off a large polarised ^6LiD target and cover the range 0.006 < x <
0.7 and 1 < Q^2 < 100 (GeV/c)^2. In leading order QCD (LO) the asymmetry
A_d^{h^{+}-h^{-}} measures the valence quark polarisation and provides an
evaluation of the first moment of Delta u_v + Delta d_v which is found to be
equal to 0.40 +- 0.07 (stat.) +- 0.05 (syst.) over the measured range of x at
Q^2 = 10 (GeV/c)^2. When combined with the first moment of g_1^d previously
measured on the same data, this result favours a non-symmetric polarisation of
light quarks Delta u-bar = - Delta d-bar at a confidence level of two standard
deviations, in contrast to the often assumed symmetric scenario Delta u-bar =
Delta d-bar = Delta s-bar = Delta s.


title: KLOE extraction of $a_\mu^{\pi\pi}$ in the mass range [0.35,0.95] GeV^2

abstract:
  The KLOE Experiment at the $\phi$ factory DA$\Phi$NE, has measured the cross
section $\sigma(e^+e^-\to\pi^+\pi^-\gamma)$ using two different selection
schemes: requiring the photon emission at small polar angle and detecting the
photon at large polar angle in the calorimeter. Using a theoretical radiator
function we extract the pion form factor and obtain the $\pi\pi$ contribution
to the anomalous magnetic moment of the muon. Results presented here come from
the analysis of 240 pb^{-1} collected in 2002, with improved systematic
uncertainty with respect to the published KLOE analysis. We also include an
update of the previous analysis.


title:
The dwarf low surface brightness population in different environments of
  the Local Universe

abstract:
  The nature of the dwarf galaxy population as a function of location in the
cluster and within different environments is investigated. We have previously
described the results of a search for low surface brightness objects in data
drawn from an East-West strip of the Virgo cluster (Sabatini et al., 2003) and
have compared this to a large area strip outside of the cluster (Roberts et
al., 2004). In this talk I compare the East-West data (sampling sub-cluster A
and outward) to new data along a North-South cluster strip that samples a
different region (part of sub-cluster A, and the N,M clouds) and with data
obtained for the Ursa Major cluster and fields around the spiral galaxy M101.
The sample of dwarf galaxies in different environments is obtained from uniform
datasets that reach central surface brightness values of ~26 B mag/arcsec^2 and
an apparent B magnitude of 21 (M_B=-10 for a Virgo Cluster distance of 16 Mpc).
We discuss and interpret our results on the properties and distribution of
dwarf low surface brightness galaxies in the context of variuos physical
processes that are thought to act on galaxies as they form and evolve.


title: QCD prerequisites for extra dimension searches

abstract:
  For the dilepton production at hadron collider in TeV scale gravity models,
inclusion of QCD corrections to NLO stabilises the cross section with respect
to scale variations. The K-factors for the various distributions for the ADD
and RS model at both LHC and Tevatron are presented.


title: Geometrical derivation of the Boltzmann factor

abstract:
  We show that the Boltzmann factor has a geometrical origin. Its derivation
follows from the microcanonical picture. The Maxwell-Boltzmann distribution or
the wealth distribution in human society are some direct applications of this
new interpretation.

categories: nlin.CD cond-mat.stat-mech cs.MA physics.soc-ph


title: Dewetting of a solid monolayer

abstract:
  We report on the dewetting of a monolayer on a solid substrate, where mass
transport occurs via surface diffusion. For a wide range of parameters, a
labyrinthine pattern of bilayer islands is formed. An irreversible regime and a
thermodynamic regime are identified. In both regimes, the velocity of a
dewetting front, the wavelength of the bilayer island pattern, and the rate of
nucleation of dewetted zones are obtained. We also point out the existence of a
scaling behavior, which is analyzed by means of a geometrical model.


title: Chain of Separable Binary Goppa Codes and their Minimal Distance

abstract:
  It is shown that subclasses of separable binary Goppa codes, $\Gamma(L,G)$ -
codes, with $L=\{\alpha \in GF(2^{2l}):G(\alpha)\neq 0 \}$ and special Goppa
polynomials G(x) can be presented as a chain of embedded codes. The true
minimal distance has been obtained for all codes of the chain.


title: Local structure of directed networks

abstract:
  Previous work on undirected small-world networks established the paradigm
that locally structured networks tend to have high density of short loops. On
the other hand, many realistic networks are directed. Here we investigate the
local organization of directed networks and find, surprisingly, that real
networks often have very few short loops as compared to random models. We
develop a theory and derive conditions for determining if a given network has
more or less loops than its randomized counterpart. These findings carry broad
implications for structural and dynamical processes sustained by directed
networks.


title: 1-join composition for $\alpha$-critical graphs

abstract:
  Given two graphs G and H its 1-{\it join} is the graph obtained by taking the
disjoint union of G and H and adding all the edges between a nonempty subset of
vertices of G and a nonempty subset of vertices of H. In general, composition
operations of graphs has played a fundamental role in some structural results
of graph theory and in particular the 1-join composition has played an
important role in decomposition theorems of several class of graphs such as the
claw-free graphs, the bull-free graphs, the perfect graphs, etc.
  A graph G is called {\it $\alpha$-critical} if $\alpha(G\setminus e)>
\alpha(G)$ for all the edges e of G, where $\alpha(G)$, the {\it stability
number} of G, is equal to the maximum cardinality of a stable set of G, and a
set of vertices M of G is {\it stable} if no two vertices in M are adjacent.
The study $\alpha$-critical graphs is important, for instance a complete
description of $\alpha$-critical graphs would yield a good characterization of
the stability number of G.
  In this paper we give necessary and sufficient conditions that G and H must
satisfy in order to its 1-join will be an $\alpha$-critical graph. Therefore we
get a very useful way to construct basic $\alpha$-critical graphs using the
1-join of graphs.


title:
The electron electric dipole moment enhancement factors of Rubidium and
  Caesium atoms

abstract:
  The enhancement factors of the electric dipole moment (EDM) of the ground
states of two paramagnetic atoms; rubidium (Rb) and caesium (Cs) which are
sensitive to the electron EDM are computed using the relativistic
coupled-cluster theory and our results are compared with the available
calculations and measurements. The possibility of improving the limit for the
electron EDM using the results of our present work is pointed out.


title: Non-independent continuous time random walks

abstract:
  The usual development of the continuous time random walk (CTRW) assumes that
jumps and time intervals are a two-dimensional set of independent and
identically distributed random variables. In this paper we address the
theoretical setting of non-independent CTRW's where consecutive jumps and/or
time intervals are correlated. An exact solution to the problem is obtained for
the special but relevant case in which the correlation solely depends on the
signs of consecutive jumps. Even in this simple case some interesting features
arise such as transitions from unimodal to bimodal distributions due to
correlation. We also develop the necessary analytical techniques and
approximations to handle more general situations that can appear in practice.


title:
An integrable discretization of the rational su(2) Gaudin model and
  related systems

abstract:
  The first part of the present paper is devoted to a systematic construction
of continuous-time finite-dimensional integrable systems arising from the
rational su(2) Gaudin model through certain contraction procedures. In the
second part, we derive an explicit integrable Poisson map discretizing a
particular Hamiltonian flow of the rational su(2) Gaudin model. Then, the
contraction procedures enable us to construct explicit integrable
discretizations of the continuous systems derived in the first part of the
paper.


title:
Neutrino production states in oscillation phenomena - are they pure or
  mixed?

abstract:
  General quantum mechanical states of neutrinos produced by mechanisms outside
the Standard Model are discussed. The neutrino state is described by the
Maki-Nakagawa-Sakata-Pontecorvo unitary mixing matrix only in the case of
relativistic neutrinos and Standard Model left-handed charge current
interaction. The problem of Wigner spin rotation caused by Lorentz
transformation from the rest production frame to the laboratory frame is
considered. Moreover, the mixture of the neutrino states as a function of their
energy and parameters from the extension of the Standard Model are
investigated. Two sources of mixture, the appearance of subdominant helicity
states, and mass mixing with several different mixing matrices are studied.


title: On some properties of $\sigma(N)$

abstract:
  We show asymptotic upper and lower bounds for the greatest common divisor of
N and $\sigma(N)$. We also show that there are infinitely many integers N with
fairly large g.c.d. of N and $\sigma(N)$.


title:
Kinetic Energy Density Study of Some Representative Semilocal Kinetic
  Energy Functionals

abstract:
  There is a number of explicit kinetic energy density functionals for
non-interacting electron systems that are obtained in terms of the electron
density and its derivatives. These semilocal functionals have been widely used
in the literature. In this work we present a comparative study of the kinetic
energy density of these semilocal functionals, stressing the importance of the
local behavior to assess the quality of the functionals. We propose a quality
factor that measures the local differences between the usual orbital-based
kinetic energy density distributions and the approximated ones, allowing to
ensure if the good results obtained for the total kinetic energies with these
semilocal functionals are due to their correct local performance or to error
cancellations. We have also included contributions coming from the laplacian of
the electron density to work with an infinite set of kinetic energy densities.
For all the functionals but one we have found that their success in the
evaluation of the total kinetic energy are due to global error cancellations,
whereas the local behavior of their kinetic energy density becomes worse than
that corresponding to the Thomas-Fermi functional.


title:
Protection of entanglement from sudden death using continuous dynamical
  decoupling

abstract:
  We show that continuous dynamical decoupling can protect a two-qubit
entangled state from sudden death at finite temperature due to uncorrelated
dephasing, bit flipping, and dissipation. We consider a situation where an
entangled state shared between two non-interacting qubits is initially prepared
and left evolve under the environmental perturbations and the protection of
external fields. To illustrate the protection of the entanglement, we solve
numerically a master equation in the Born approximation, considering
independent boson fields at the same temperature coupled to the different error
agents of each qubit.


title: Twisted mass lattice QCD

abstract:
  I review the theoretical foundations, properties as well as the simulation
results obtained so far of a variant of the Wilson lattice QCD formulation:
Wilson twisted mass lattice QCD. Emphasis is put on the discretization errors
and on the effects of these discretization errors on the phase structure for
Wilson-like fermions in the chiral limit. The possibility to use in lattice
simulations different lattice actions for sea and valence quarks to ease the
renormalization patterns of phenomenologically relevant local operators, is
also discussed.


title:
Bounds for the Superfluid Fraction from Exact Quantum Monte Carlo Local
  Densities

abstract:
  For solid 4He and solid p-H2, using the flow-energy-minimizing one-body phase
function and exact T=0 K Monte Carlo calculations of the local density, we have
calculated the phase function, the velocity profile and upper bounds for the
superfluid fraction f_s. At the melting pressure for solid 4He we find that f_s
< 0.20-0.21, about ten times what is observed. This strongly indicates that the
theory for the calculation of these upper bounds needs substantial
improvements.


title:
High-pressure study of X-ray diffuse scattering in ferroelectric
  perovskites

abstract:
  We present a high-pressure x-ray diffuse scattering study of the ABO$_3$
ferroelectric perovskites BaTiO_3 and KNbO_3. The well-known diffuse lines are
observed in all the phases studied. In KNbO_3, we show that the lines are
present up to 21.8 GPa, with constant width and a slightly decreasing
intensity. At variance, the intensity of the diffuse lines observed in the
cubic phase of BaTiO_3 linearly decreases to zero at $\sim 11$ GPa. These
results are discussed with respect to x-ray absorption measurements, which
leads to the conclusion that the diffuse lines are only observed when the B
atom is off the center of the oxygen tetrahedron. The role of such disorder on
the ferroelectric instability of perovskites is discussed.


title:
Concavity for nuclear binding energies, thermodynamical functions and
  density functionals

abstract:
  Sequences of experimental ground-state energies for both odd and even $A$ are
mapped onto concave patterns cured from convexities due to pairing and/or shell
effects. The same patterns, completed by a list of excitation energies, give
numerical estimates of the grand potential $\Omega(\beta,\mu)$ for a mixture of
nuclei at low or moderate temperatures $T=\beta^{-1}$ and at many chemical
potentials $\mu.$ The average nucleon number $<{\bf A} >(\beta,\mu)$ then
becomes a continuous variable, allowing extrapolations towards nuclear masses
closer to drip lines. We study the possible concavity of several
thermodynamical functions, such as the free energy and the average energy, as
functions of $<{\bf A} >.$ Concavity, which always occur for the free energy
and is usually present for the average energy, allows easy interpolations and
extrapolations providing upper and lower bounds, respectively, to binding
energies. Such bounds define an error bar for the prediction of binding
energies. Finally we show how concavity and universality are related in the
theory of the nuclear density functional.


title:
Gravitational moduli forces in small nuclei and analytical computation
  of the Newton constant

abstract:
  The magnitude of gravity at subatomic distances was investigated in the
nuclear size range by examining the vibrational kinetic energy of baryons and
quarks, treated as waveparticles and strings, in the 4He and 2H nuclei. Due to
the relativistic increase in mass and concomitant wave particle confinement at
high vibrational energies, it is found that gravitational moduli forces are
significant and comparable in size with the strong interaction forces exerted
between color quarks. This leads to analytical expressions for the
gravitational constant and for the binding energies of the 4He and 2H nuclei in
close agreement with experiment.


title: Rank-based inference for bivariate extreme-value copulas

abstract:
  Consider a continuous random pair $(X,Y)$ whose dependence is characterized
by an extreme-value copula with Pickands dependence function $A$. When the
marginal distributions of $X$ and $Y$ are known, several consistent estimators
of $A$ are available. Most of them are variants of the estimators due to
Pickands [Bull. Inst. Internat. Statist. 49 (1981) 859--878] and
Cap\'{e}ra\`{a}, Foug\`{e}res and Genest [Biometrika 84 (1997) 567--577]. In
this paper, rank-based versions of these estimators are proposed for the more
common case where the margins of $X$ and $Y$ are unknown. Results on the limit
behavior of a class of weighted bivariate empirical processes are used to show
the consistency and asymptotic normality of these rank-based estimators. Their
finite- and large-sample performance is then compared to that of their
known-margin analogues, as well as with endpoint-corrected versions thereof.
Explicit formulas and consistent estimates for their asymptotic variances are
also given.


title:
Microscopic studies of solid 4He with Path Integral Projector Monte
  Carlo

abstract:
  We have investigated the ground state properties of solid $^4$He with the
Shadow Path Integral Ground State method. This exact T=0 K projector method
allows to describes quantum solids without introducing any a priori equilibrium
position. We have found that the efficiency in computing off-diagonal
properties in the solid phase sensibly improves when the direct sampling of
permutations, in principle not required, is introduced. We have computed the
exact one-body density matrix (obdm) in large commensurate 4He crystal finding
a decreasing condensate fraction with increasing imaginary time of projection,
making our result not conclusive on the presence of Bose-Einstein condensation
in bulk solid 4He. We can only give an upper bound of 2.5 times 10^-8 on the
condensate fraction. We have exploited the SPIGS method to study also 4He
crystal containing grain boundaries by computing the related surface energy and
the obdm along these defects. We have found that also highly symmetrical grain
boundaries have a finite condensate fraction. We have also derived a route for
the estimation of the true equilibrium concentration of vacancies x_v in bulk
T=0 K solid 4He, which is shown to be finite, x_v=0.0014(1) at the melting
density, when computed with the variational shadow wave function technique.


title:
Collinear improvement of the BFKL kernel in the electroproduction of two
  light vector mesons

abstract:
  The use of the BFKL kernel improved by the inclusion of subleading terms
generated by renormalization group (RG) analysis has been suggested to cure the
instabilities in the behavior of the BFKL Green's function in the
next-to-leading approximation (NLA). We test the performance of a RG-improved
kernel in the determination of the amplitude of a physical process, the
electroproduction of two light vector mesons, in the BFKL approach in the NLA.
We find that a smooth behavior of the amplitude with the center-of-mass energy
can be achieved, setting the renormalization and energy scales appearing in the
subleading terms to values much closer to the kinematical scales of the process
than in the approaches based on the unimproved kernel.


title:
On the ternary Goldbach problem with primes in arithmetic progressions
  of a common module

abstract:
  For A,epsilon>0 and any sufficiently large odd n we show that for almost all
k up to n^{1/5-epsilon} there exists a representation n=p1+p2+p3 with primes in
residue classes b1,b2,b3 mod k for almost all admissible triplets b1,b2,b3 of
reduced residues mod k.


title: A deterministic version of Pollard's p-1 algorithm

abstract:
  In this article we present applications of smooth numbers to the
unconditional derandomization of some well-known integer factoring algorithms.
  We begin with Pollard's $p-1$ algorithm, which finds in random polynomial
time the prime divisors $p$ of an integer $n$ such that $p-1$ is smooth. We
show that these prime factors can be recovered in deterministic polynomial
time. We further generalize this result to give a partial derandomization of
the $k$-th cyclotomic method of factoring ($k\ge 2$) devised by Bach and
Shallit.
  We also investigate reductions of factoring to computing Euler's totient
function $\phi$. We point out some explicit sets of integers $n$ that are
completely factorable in deterministic polynomial time given $\phi(n)$. These
sets consist, roughly speaking, of products of primes $p$ satisfying, with the
exception of at most two, certain conditions somewhat weaker than the
smoothness of $p-1$. Finally, we prove that $O(\ln n)$ oracle queries for
values of $\phi$ are sufficient to completely factor any integer $n$ in less
than $\exp\Bigl((1+o(1))(\ln n)^{{1/3}} (\ln\ln n)^{{2/3}}\Bigr)$ deterministic
time.


title: EDGE: Explorer of Diffuse emission and Gamma-ray burst Explosions

abstract:
  How structures on various scales formed and evolved from the early Universe
up to present time is a fundamental question of astrophysical cosmology. EDGE
will trace the cosmic history of the baryons from the early generations of
massive star by Gamma-Ray Burst (GRB) explosions, through the period of cluster
formation, down to very low redshifts, when between a third and one half of the
baryons are expected to reside in cosmic filaments undergoing gravitational
collapse by dark matter (Warm Hot Intragalactic Medium: WHIM). In addition
EDGE, with its unprecedented observational capabilities, will provide key
results on several other topics. The science is feasible with a medium class
mission using existing technology combined with innovative instrumental and
observational capabilities on a single satellite by: a) observing with fast
reaction Gamma-Ray Bursts with a high spectral resolution (R ~ 500). This
enables the study of their (star-forming) environment from the Dark to the
local Universe and the use of GRB as back light of large scale cosmological
structures b) Observing and surveying extended sources (clusters, WHIM) with
high sensitivity using two wide field of view X-ray telescopes (one with a high
angular resolution and the other with a high spectral resolution).


title: Queues, stores, and tableaux

abstract:
  Consider the single server queue with an infinite buffer and a FIFO
discipline, either of type M/M/1 or Geom/Geom/1. Denote by A the arrival
process and by s the services. Assume the stability condition to be satisfied.
Denote by D the departure process in equilibrium and by r the time spent by the
customers at the very back of the queue. We prove that (D,r) has the same law
as (A,s) which is an extension of the classical Burke Theorem. In fact, r can
be viewed as the departures from a dual storage model. This duality between the
two models also appears when studying the transient behavior of a tandem by
means of the RSK algorithm: the first and last row of the resulting
semi-standard Young tableau are respectively the last instant of departure in
the queue and the total number of departures in the store.


title:
Semiclassical theory of charged pion radiation by nucleons in a strong
  homogeneous magnetic field

abstract:
  Charged pions produced in very high energy hadronic interactions might be the
dominant source of cosmic neutrinos in the GeV--TeV range. Spectral energy
power of \pi^+ radiation by high energy protons moving in strong magnetic
fields typical for magnetars is determined with a semiclassical treatment of
the effective pion-nucleon model. The main characteristics emerging from a
saddle point approximation to the summation over the allowed range of Landau
levels is a sharp lower cut: E_\pi>0.25 E_p. The magnitude of the spectral
power agrees in this region with the synchrotron radiation spectra of neutral
pions.


title: Parton Distributions: Progress and Challenges

abstract:
  We briefly discuss recent research on the spin-averaged parton densities of
the proton, focusing on some aspects relevant to hard processes at the LHC.
Specifically, after recalling the basic framework and the need for higher-order
calculations, we address the evolution equations governing the scale dependence
of the parton distributions and their solution, schemes for initial conditions
and the inclusion of heavy quarks, recent progress on fits to data, and future
high-precision constraints from LHC measurements.


title:
Post Common Envelope Binaries from SDSS. I: 101 white dwarf main
  sequence binaries with multiple SDSS spectroscopy

abstract:
  We present a detailed analysis of 101 white dwarf-main sequence binaries
(WDMS) from the Sloan Digital Sky Survey (SDSS) for which multiple SDSS spectra
are available. We detect significant radial velocity variations in 18 WDMS,
identifying them as post common envelope binaries (PCEBs) or strong PCEB
candidates. Strict upper limits to the orbital periods are calculated, ranging
from 0.43 to 7880 d. Given the sparse temporal sampling and relatively low
spectral resolution of the SDSS spectra, our results imply a PCEB fraction of
>=15% among the WDMS in the SDSS data base. Using a spectral
decomposition/fitting technique we determined the white dwarf effective
temperatures and surface gravities, masses, and secondary star spectral types
for all WDMS in our sample. Two independent distance estimates are obtained
from the flux scaling factors between the WDMS spectra, and the white dwarf
models and main sequence star templates, respectively. Approximately one third
of the systems in our sample show a significant discrepancy between the two
distance estimates. In the majority of discrepant cases, the distance estimate
based on the secondary star is too large. A possible explanation for this
behaviour is that the secondary star spectral types that we determined from the
SDSS spectra are systematically too early by 1-2 spectral classes. This
behaviour could be explained by stellar activity, if covering a significant
fraction of the star by cool dark spots will raise the temperature of the
inter-spot regions. Finally, we discuss the selection effects of the WDMS
sample provided by the SDSS project.


title:
What hydrodynamical simulations tell us about the radial properties of
  the stellar populations in Ellipticals

abstract:
  Elliptical galaxies probably host the most metal rich stellar populations in
the Universe. The processes leading to both the formation and the evolution of
such stars are discussed by means of a new gas dynamical model which implements
detailed chemical evolution prescriptions. Moreover, the radial variations in
the metallicity distribution of these stars are investigated by means of
G-dwarf-like diagrams. By comparing model predictions with observations, we
derive a picture of galaxy formation in which the higher is the mass of the
galaxy, the shorter are the infall and the star formation timescales. The
galaxies seem to have formed outside-in, namely the most external regions
accrete gas, form stars and develop a galactic wind very quickly (a few Myr)
compared to the central core, where the star formation can last up to 1 Gyr. We
show for the first time a model able in reproducing the mass-metallicity and
the color-magnitude relations as well as the radial metallicity gradient, and,
at the same time, the observed either positive or negative slopes in the
[alpha/Fe] abundace ratio gradient in stars.


title:
Direct observation of mixing of spin-multiplets in an antiferromagnetic
  molecular nanomagnet by electron paramagnetic resonance

abstract:
  High-frequency electron paramagnetic resonance (EPR) studies of the
antiferromagnetic Mn-$[3\times 3]$ molecular grid clearly reveal a breaking of
the $\Delta S = 0$ selection rule, providing direct evidence for the mixing of
spin wavefunctions ($S$-mixing) induced by the comparable exchange and
magneto-anisotropy energy scales within the grid. This finding highlights the
potential utility of EPR for studies of exchange splittings in molecular
nanomagnets, which is normally considered the sole domain of inelastic neutron
scattering, thereby offering improved sensitivity and energy resolution.


title:
Functional renormalization group in the broken symmetry phase: momentum
  dependence and two-parameter scaling of the self-energy

abstract:
  We include spontaneous symmetry breaking into the functional renormalization
group (RG) equations for the irreducible vertices of Ginzburg-Landau theories
by augmenting these equations by a flow equation for the order parameter, which
is determined from the requirement that at each RG step the vertex with one
external leg vanishes identically. Using this strategy, we propose a simple
truncation of the coupled RG flow equations for the vertices in the broken
symmetry phase of the Ising universality class in D dimensions. Our truncation
yields the full momentum dependence of the self-energy Sigma (k) and
interpolates between lowest order perturbation theory at large momenta k and
the critical scaling regime for small k. Close to the critical point, our
method yields the self-energy in the scaling form Sigma (k) = k_c^2 sigma^{-}
(k | xi, k / k_c), where xi is the order parameter correlation length, k_c is
the Ginzburg scale, and sigma^{-} (x, y) is a dimensionless two-parameter
scaling function for the broken symmetry phase which we explicitly calculate
within our truncation.


title:
Dependence of spin dephasing on initial spin polarization in a
  high-mobility two-dimensional electron system

abstract:
  We have studied the spin dynamics of a high-mobility two-dimensional electron
system in a GaAs/Al_{0.3}Ga_{0.7}As single quantum well by time-resolved
Faraday rotation and time-resolved Kerr rotation in dependence on the initial
degree of spin polarization, P, of the electrons. By increasing the initial
spin polarization from the low-P regime to a significant P of several percent,
we find that the spin dephasing time, $T_2^\ast$, increases from about 20 ps to
200 ps; Moreover, $T_2^\ast$ increases with temperature at small spin
polarization but decreases with temperature at large spin polarization. All
these features are in good agreement with theoretical predictions by Weng and
Wu [Phys. Rev. B {\bf 68}, 075312 (2003)]. Measurements as a function of spin
polarization at fixed electron density are performed to further confirm the
theory. A fully microscopic calculation is performed by setting up and
numerically solving the kinetic spin Bloch equations, including the
D'yakonov-Perel' and the Bir-Aronov-Pikus mechanisms, with {\em all} the
scattering explicitly included. We reproduce all principal features of the
experiments, i.e., a dramatic decrease of spin dephasing with increasing $P$
and the temperature dependences at different spin polarizations.


title:
Modeling of Transitional Channel Flow Using Balanced Proper Orthogonal
  Decomposition

abstract:
  We study reduced-order models of three-dimensional perturbations in
linearized channel flow using balanced proper orthogonal decomposition (BPOD).
The models are obtained from three-dimensional simulations in physical space as
opposed to the traditional single-wavenumber approach, and are therefore better
able to capture the effects of localized disturbances or localized actuators.
In order to assess the performance of the models, we consider the impulse
response and frequency response, and variation of the Reynolds number as a
model parameter. We show that the BPOD procedure yields models that capture the
transient growth well at a low order, whereas standard POD does not capture the
growth unless a considerably larger number of modes is included, and even then
can be inaccurate. In the case of a localized actuator, we show that POD modes
which are not energetically significant can be very important for capturing the
energy growth. In addition, a comparison of the subspaces resulting from the
two methods suggests that the use of a non-orthogonal projection with adjoint
modes is most likely the main reason for the superior performance of BPOD. We
also demonstrate that for single-wavenumber perturbations, low-order BPOD
models reproduce the dominant eigenvalues of the full system better than POD
models of the same order. These features indicate that the simple, yet accurate
BPOD models are a good candidate for developing model-based controllers for
channel flow.


title:
Mean-field description of ultracold Bosons on disordered two-dimensional
  optical lattices

abstract:
  In the present paper we describe the properties induced by disorder on an
ultracold gas of Bosonic atoms loaded into a two-dimensional optical lattice
with global confinement ensured by a parabolic potential. Our analysis is
centered on the spatial distribution of the various phases, focusing
particularly on the superfluid properties of the system as a function of
external parameters and disorder amplitude. In particular, it is shown how
disorder can suppress superfluidity, while partially preserving the system
coherence.


title:
Evidence for out-of-equilibrium crystal nucleation in suspensions of
  oppositely charged colloids

abstract:
  We report a numerical study of the rate of crystal nucleation in a binary
suspension of oppositely charged colloids. Two different crystal structures
compete in the thermodynamic conditions under study. We find that the crystal
phase that nucleates is metastable and, more surprisingly, its nucleation free
energy barrier is not the lowest one. This implies that, during nucleation,
there is insufficient time for sub-critical nuclei to relax to their lowest
free-energy structure. Such behavior is in direct contradiction with the common
assumption that the phase that crystallizes most readily is the one with the
lowest free-energy barrier for nucleation. The phenomenon that we describe
should be relevant for crystallization experiments where competing solid
structures are not connected by an easy transformation.


title:
Dynamics of the attractive 1D Bose gas: analytical treatment from
  integrability

abstract:
  The physics of the attractive one-dimensional Bose gas (Lieb-Liniger model)
is investigated with techniques based on the integrability of the system.
Combining a knowledge of particle quasi-momenta to exponential precision in the
system size with determinant representations of matrix elements of local
operators coming from the Algebraic Bethe Ansatz, we obtain rather general
analytical results for the zero-temperature dynamical correlation functions of
the density and field operators. Our results thus provide quantitative
predictions for possible future experiments in atomic gases or optical
waveguides.

categories: cond-mat.str-el cond-mat.stat-mech hep-th quant-ph


title: Note on deconfinement temperature with chemical potential from AdS/CFT

abstract:
  In this note we study the first-order Hawking-Page phase transition of
R-charged black hole in truncated Anti-de Sitter space of various dimensions.
This corresponds to confinement/deconfinement phase transition in the dual
gauge field theory with fixed chemical potential. We demonstrate in general
this critical temperature decreases with increasing charge density but with
decreasing IR cutoff.


title: Renormalization group approach to exact sampling

abstract:
  In this Letter, we use a general renormalization-group algorithm to implement
Propp and Wilson's "coupling from the past" approach to complex physical
systems. Our algorithm follows the evolution of the entire configuration space
under the Markov chain Monte Carlo dynamics from parts of the configurations
(patches) on increasing length scales, and it allows us to generate "exact
samples" of the Boltzmann distribution, which are rigorously proven to be
uncorrelated with the initial condition. We validate our approach in the
two-dimensional Ising spin glass on lattices of size 64 x 64.


title: The Hochschild cohomology of a Poincar\'e algebra

abstract:
  In this note, we define the notion of a cactus set, and show that its
geometric realization is naturally an algebra over Voronov's cactus operad,
which is equivalent to the framed 2-dimensional little disks operad
$\mathcal{D}_2$. Using this, we show that the Hochschild cohomology of a
Poincar\'e algebra A is an algebra over (the chain complexes of)
$\mathcal{D}_2$.


title: Supersymmetry and Goldstino-like Mode in Bose-Fermi Mixtures

abstract:
  Supersymmetry is assumed to be a basic symmetry of the world in many high
energy theories, but none of the super partners of any known elementary
particle has been observed yet. We argue that supersymmetry can also be
realized and studied in ultracold atomic systems with a mixture of bosons and
fermions, with properly tuned interactions and single particle dispersion. We
further show that in such non-releativistic systems supersymmetry is either
spontaneously broken, or explicitly broken by a chemical potential difference
between the bosons and fermions. In both cases the system supports a sharp
fermionic collective mode or the so-called Goldstino, due to supersymmetry. We
also discuss possible ways to detect the Goldstino mode experimentally.


title:
XMM-Newton temperature maps for five intermediate redshift clusters of
  galaxies

abstract:
  We have analyzed XMM-Newton archive data for five clusters of galaxies
(redshifts 0.223 to 0.313) covering a wide range of dynamical states, from
relaxed objects to clusters undergoing several mergers. We present here
temperature maps of the X-ray gas together with a preliminary interpretation of
the formation history of these clusters.


title:
Characterizations of probability distributions via bivariate regression
  of record values

abstract:
  Bairamov et al. (Aust N Z J Stat 47:543-547, 2005) characterize the
exponential distribution in terms of the regression of a function of a record
value with its adjacent record values as covariates. We extend these results to
the case of non-adjacent covariates. We also consider a more general setting
involving monotone transformations. As special cases, we present
characterizations involving weighted arithmetic, geometric, and harmonic means.


title:
The ATLAS Level-1 Trigger: Status of the System and First Results from
  Cosmic-Ray Data

abstract:
  The ATLAS detector at CERN's Large Hadron Collider (LHC) will be exposed to
proton-proton collisions from beams crossing at 40 MHz. At the design
luminosity of 10^34 cm^-2 s^-1 there are on average 23 collisions per bunch
crossing. A three-level trigger system will select potentially interesting
events in order to reduce the read-out rate to about 200 Hz. The first trigger
level is implemented in custom-built electronics and makes an initial fast
selection based on detector data of coarse granularity. It has to reduce the
rate by a factor of 10^4 to less than 100 kHz. The other two consecutive
trigger levels are in software and run on PC farms. We present an overview of
the first-level trigger system and report on the current installation status.
Moreover, we show analysis results of cosmic-ray data recorded in situ at the
ATLAS experimental site with final or close-to-final hardware.


title: Systematic errors of bound-state parameters obtained with SVZ sum rules

abstract:
  We study systematic errors of the ground-state parameters obtained by
Shifman-Vainshtein-Zakharov (SVZ) sum rules, making use of the
harmonic-oscillator potential model as an example. In this case, one knows the
exact solution for the polarization operator, which allows one to obtain both
the OPE to any order and the parameters (masses and decay constants) of the
bound states. We determine the parameters of the ground state making use of the
standard procedures of the method of sum rules, and compare the obtained
results with the known exact values. We show that in the situation when the
continuum contribution to the polarization operator is not known and is
modelled by an effective continuum, the method of sum rules does not allow to
control the systematic uncertainties of the extracted ground-state parameters.


title: Services within a busy period of an M/M/1 queue and Dyck paths

abstract:
  We analyze the service times of customers in a stable M/M/1 queue in
equilibrium depending on their position in a busy period. We give the law of
the service of a customer at the beginning, at the end, or in the middle of the
busy period. It enables as a by-product to prove that the process of instants
of beginning of services is not Poisson. We then proceed to a more precise
analysis. We consider a family of polynomial generating series associated with
Dyck paths of length 2n and we show that they provide the correlation function
of the successive services in a busy period with (n+1) customers.


title: Nonrelativistic phase in gamma-ray burst afterglows

abstract:
  The discovery of multiband afterglows definitely shows that most $\gamma$-ray
bursts are of cosmological origin. $\gamma$-ray bursts are found to be one of
the most violent explosive phenomena in the Universe, in which astonishing
ultra-relativistic motions are involved. In this article, the multiband
observational characteristics of $\gamma$-ray bursts and their afterglows are
briefly reviewed. The standard model of $\gamma$-ray bursts, i.e. the fireball
model, is described. Emphasis is then put on the importance of the
nonrelativistic phase of afterglows. The concept of deep Newtonian phase is
elaborated. A generic dynamical model that is applicable in both the
relativistic and nonrelativistic phases is introduced. Based on these
elaborations, the overall afterglow behaviors, from the very early stages to
the very late stages, can be conveniently calculated.


title: Cosmological WIMPs, Higgs Dark Matter and GLAST

abstract:
  Measurement of the extragalactic background (EGBR) of diffuse gamma-rays is
perhaps one of the most challenging tasks for future gamma-ray observatories,
such as GLAST. This is because any determination will depend on accurate
subtraction of the galactic diffuse and celestial foregrounds, as well as point
sources. However, the EGBR is likely to contain very rich information about the
high energy-gamma ray sources of the Universe at cosmological distances. We
focus on the ability of GLAST to detect a signal from dark matter in the EGBR.
We present sensitivities for generic thermal WIMPs and the Inert Higgs Doublet
Model. Also we discuss the various aspects of astrophysics and particle physics
that determines the shape and strength of the signal, such as dark matter halo
properties and different dark matter candidates. Other possible sources to the
EGBR are also discussed, such as unresolved AGNs, and viewed as backgrounds.


title: Star formation in isolated AMIGA galaxies: dynamical influence of bars

abstract:
  Star formation depends strongly both on the local environment of galaxies,
and on the internal dynamics of the interstellar medium. To disentangle the two
effects, we obtained, in the framework of the AMIGA project, Ha and Gunn r
photometric data for more than 200 spiral galaxies lying in very low-density
regions of the local Universe. We characterise the Ha emission, tracing current
star formation, of the 45 largest and less inclined galaxies observed for which
we estimate the torques between the gas and the bulk of the optical matter. We
could subsequently study the Ha morphological aspect of these isolated spiral
galaxies. Using Fourier analysis, we focus on the modes of the spiral arms and
also on the strength of the bars, computing the torques between the gas and
newly formed stars (Ha) and the bulk of the optical matter (Gunn r). We
interpret the various bar/spiral morphologies observed in terms of the secular
evolution experienced by galaxies in isolation. We also classify the different
spatial distributions of star forming regions in barred galaxies. The observed
frequency of particular patterns brings constraints on the lifetime of the
various evolution phases. We propose an evolutive sequence accounting for the
transitions between the different phases we could observe. Isolated galaxies
appear not to be preferentially barred or unbarred. Through numerical
simulations, trying to fit the Ha distributions yields constraints on the star
formation law, which is likely to differ from a genuine Schmidt law. In
particular, it is probable that the relative velocity of the gas in the bar
also needs to be taken into account.


title:
Excitation of spin dynamics by spin-polarized current in vortex state
  disks

abstract:
  A spin-polarized current with the polarization perpendicular to the plane of
a vortex-state disk results in renormalization of the effective damping for a
given magnetization mode, and the effective damping becomes zero if the current
exceeds a threshold value. The lowest threshold current corresponds to the
lowest frequency vortex gyroscopic mode. For larger values of the current the
dynamic magnetization state is characterized by precession of the vortex around
the dot center with non-small amplitude and higher frequency.


title:
Vertex operator algebras associated to certain admissible modules for
  affine Lie algebras of type A

abstract:
  Let $L(-{1/2}(l+1),0)$ be the simple vertex operator algebra associated to an
affine Lie algebra of type $A_{l}^{(1)}$ with the lowest admissible
half-integer level $-{1/2}(l+1)$, for even l. We study the category of weak
modules for that vertex operator algebra which are in category $\cal{O}$ as
modules for the associated affine Lie algebra. We classify irreducible objects
in that category and prove semisimplicity of that category.


title: Study of the process e+e- -> omega p0 with the KLOE detector

abstract:
  Using ~600 pb-1 collected with the KLOE detector at DAPhiNE, we have studied
the production cross section of pi+ pi- pi0 pi0 and p0p0 gamma final states in
e+e- collisions at center of mass energies between 1000 and 1030 MeV. By
fitting the observed interference pattern around Mphi for both final states, we
extract a measurement (preliminary) for the ratio Gamma(omega -> pi0
gamma)/Gamma(omega -> pi+ pi- pi0) = 0.0934 +- 0.0022. Since these two final
states represent the 98% of the omega decay channels, we use unitarity to
derive BR(omega -> pi+pi-pi0)= (89.94 +- 0.23)% and BR(omega -> pi0 gamma) =
(8.40 +- 0.19)%. Moreover, the parameters describing the e+e- -> pi+ pi- pi0
pi0 reaction around Mphi are used to extract the branching fraction for the OZI
and G-parity violating phi -> omega pi0 decay: BR(phi -> omega pi0) = (5.63 +-
0.70) x 10^-5.