title: On Semimeasures Predicting Martin-Loef Random Sequences

abstract:
  Solomonoff's central result on induction is that the posterior of a universal
semimeasure M converges rapidly and with probability 1 to the true sequence
generating posterior mu, if the latter is computable. Hence, M is eligible as a
universal sequence predictor in case of unknown mu. Despite some nearby results
and proofs in the literature, the stronger result of convergence for all
(Martin-Loef) random sequences remained open. Such a convergence result would
be particularly interesting and natural, since randomness can be defined in
terms of M itself. We show that there are universal semimeasures M which do not
converge for all random sequences, i.e. we give a partial negative answer to
the open problem. We also provide a positive answer for some non-universal
semimeasures. We define the incomputable measure D as a mixture over all
computable measures and the enumerable semimeasure W as a mixture over all
enumerable nearly-measures. We show that W converges to D and D to mu on all
random sequences. The Hellinger distance measuring closeness of two
distributions plays a central role.


title:
The non-viscous Burgers equation associated with random positions in
  coordinate space: a threshold for blow up behaviour

abstract:
  It is well known that the solutions to the non-viscous Burgers equation
develop a gradient catastrophe at a critical time provided the initial data
have a negative derivative in certain points. We consider this equation
assuming that the particle paths in the medium are governed by a random process
with a variance which depends in a polynomial way on the velocity. Given an
initial distribution of the particles which is uniform in space and with the
initial velocity linearly depending on the position we show both analytically
and numerically that there exists a threshold effect: if the power in the above
variance is less than 1, then the noise does not influence the solution
behavior, in the following sense: the mean of the velocity when we keep the
value of position fixed goes to infinity outside the origin. If however the
power is larger or equal 1, then this mean decays to zero as the time tends to
a critical value.


title: Fast learning rates for plug-in classifiers

abstract:
  It has been recently shown that, under the margin (or low noise) assumption,
there exist classifiers attaining fast rates of convergence of the excess Bayes
risk, that is, rates faster than $n^{-1/2}$. The work on this subject has
suggested the following two conjectures: (i) the best achievable fast rate is
of the order $n^{-1}$, and (ii) the plug-in classifiers generally converge more
slowly than the classifiers based on empirical risk minimization. We show that
both conjectures are not correct. In particular, we construct plug-in
classifiers that can achieve not only fast, but also super-fast rates, that is,
rates faster than $n^{-1}$. We establish minimax lower bounds showing that the
obtained rates cannot be improved.


title: Zero

abstract:
  You shall not find any new physics, because all physical events are
interpreted well-known particles (leptons, quarks, photons, gluons, W-bosons,
Z-boson) and forces which have long known (electroweak, gravity, strong
interactions).
  Contents: 1. Pointlike events and probability. 2. Leptons' moving equations
and masses. 3. Fermion-antifermion asommetry. 4. Electroweak equations. 5.
Chromatic states and gluons. 6. Asimptotic freedom, confinement, Newton's
gravity. 7. Dark energy and dark matter. 8. Events and particles. 9.
Conclusion.


title: Optimal Unambiguous Discrimination of Quantum States

abstract:
  Unambiguously distinguishing between nonorthogonal but linearly independent
quantum states is a challenging problem in quantum information processing. In
this work, an exact analytic solution to an optimum measurement problem
involving an arbitrary number of pure linearly independent quantum states is
presented. To this end, the relevant semi-definite programming task is reduced
to a linear programming one with a feasible region of polygon type which can be
solved via simplex method. The strength of the method is illustrated through
some explicit examples. Also using the close connection between the
Lewenstein-Sanpera decomposition(LSD) and semi-definite programming approach,
the optimal positive operator valued measure for some of the well-known
examples is obtain via Lewenstein-Sanpera decomposition method. {\bf Keywords:}
Optimal Unambiguous State Discrimination, Linear Programming,
Lewenstein-Sanpera decomposition. {\bf PACs Index: 03.67.Hk, 03.65.Ta, 42.50.-p


title:
A twist in the geometry of rotating black holes: seeking the cause of
  acausality

abstract:
  We investigate Kerr-Newman black holes in which a rotating charged
ring-shaped singularity induces a region which contains closed timelike curves
(CTCs). Contrary to popular belief, it turns out that the time orientation of
the CTC is opposite to the direction in which the singularity or the ergosphere
rotates. In this sense, CTCs "counter-rotate" against the rotating black hole.
We have similar results for all spacetimes sufficiently familiar to us in which
rotation induces CTCs. This motivates our conjecture that perhaps this
counter-rotation is not an accidental oddity particular to Kerr-Newman
spacetimes, but instead there may be a general and intuitively comprehensible
reason for this.


abstract:
  A two-parameter generalization of the complete elliptic integral of second
kind is expressed in terms of the Appell function $F_{4}$. This function is
further reduced to a quite simple bilinear form in the complete elliptic
integrals $K$ and $E$. The physical applications are briefly mentioned.


title:
Quantum spin correlations through the superconducting-normal phase
  transition in electron-doped superconducting Pr0.88LaCe0.12CuO4-d

abstract:
  The quantum spin fluctuations of the S = 1/2 Cu ions are important in
determining the physical properties of the high-transition temperature
(high-Tc) copper oxide superconductors, but their possible role in the electron
pairing for superconductivity remains an open question. The principal feature
of the spin fluctuations in optimally doped high-Tc superconductors is a well
defined magnetic resonance whose energy (Er) tracks Tc (as the composition is
varied) and whose intensity develops like an order parameter in the
superconducting state. We show that the suppression of superconductivity and
its associated condensation energy by a magnetic field in the electron-doped
high-Tc superconductor, Pr0.88LaCe0.12CuO4-d (Tc = 24 K), is accompanied by the
complete suppression of the resonance and the concomitant emergence of static
antiferromagnetic (AF) order. Our results demonstrate that the resonance is
intimately related to the superconducting condensation energy, and thus suggest
that it plays a role in the electron pairing and superconductivity.


title: Non-cyclic graph of a group

abstract:
  We associate a graph $\Gamma_G$ to a non locally cyclic group $G$ (called the
non-cyclic graph of $G$) as follows: take $G\backslash Cyc(G)$ as vertex set,
where $Cyc(G)=\{x\in G | \left<x,y\right> \text{is cyclic for all} y\in G\}$,
and join two vertices if they do not generate a cyclic subgroup. We study the
properties of this graph and we establish some graph theoretical properties
(such as regularity) of this graph in terms of the group ones. We prove that
the clique number of $\Gamma_G$ is finite if and only if $\Gamma_G$ has no
infinite clique. We prove that if $G$ is a finite nilpotent group and $H$ is a
group with $\Gamma_G\cong\Gamma_H$ and $|Cyc(G)|=|Cyc(H)|=1$, then $H$ is a
finite nilpotent group.
  We give some examples of groups $G$ whose non-cyclic graphs are ``unique'',
i.e., if $\Gamma_G\cong \Gamma_H$ for some group $H$, then $G\cong H$. In view
of these examples, we conjecture that every finite non-abelian simple group has
a unique non-cyclic graph. Also we give some examples of finite non-cyclic
groups $G$ with the property that if $\Gamma_G \cong \Gamma_H$ for some group
$H$, then $|G|=|H|$. These suggest the question whether the latter property
holds for all finite non-cyclic groups.


title: Neutrino oscillations in matter and in twisting magnetic fields

abstract:
  We find the solution to the Dirac equation for a massive neutrino with a
magnetic moment propagating in background matter and interacting with the
twisting magnetic field. In frames of the relativistic quantum mechanics
approach to the description of neutrino evolution we use the obtained solution
to derive neutrino wave functions satisfying the given initial condition. We
apply the results to the analysis of neutrino spin oscillations in matter under
the influence of the twisting magnetic field. Then on the basis of the yielded
results we describe spin-flavor oscillations of Dirac neutrinos that mix and
have non-vanishing matrix of magnetic moments. We again formulate the initial
condition problem, derive neutrinos wave functions and calculate the transition
probabilities for different magnetic moments matrices. The consistency of the
obtained results with the quantum mechanical treatment of spin-flavor
oscillations is discussed. We also consider several applications to
astrophysical and cosmological neutrinos.


title: Feshbach Molecules in a One-dimensional Optical Lattice

abstract:
  We present the theory of a pair of atoms in a one-dimensional optical lattice
interacting via a narrow Feshbach resonance. Using a two-channel description of
the resonance, we derive analytic results for the scattering states inside the
continuum band and the discrete bound states outside the band. We identify a
Fano resonance profile, and the survival probability of a molecule when swept
through the Bloch band of scattering states by varying an applied magnetic
field. We discuss how these results may be used to investigate the importance
of the structured nature of the continuum in experiments.


title:
Light dressed-excitons in an incoherent-electron sea: Evidence for
  Mollow-triplet and Autler-Townes doublet

abstract:
  We demonstrate that the interaction between excitons and a sea of incoherent
electrons does not preclude excitons dressing by light. We investigate the role
of exciton-electron scattering in the light dressing by measuring the dynamical
absorption spectrum of a modulation-doped CdTe quantum well, which shows a
clear evidence for significant electron scattering of the excitonic states. We
show the occurrence of dressed and correlated excitons by detecting quantum
coherent interferences through excitonic Autler-Townes doublet and ac Stark
splitting, which evolves to Mollow triplet with gain. We also evidence the
partial inhibition of the electron-exciton scattering by exciton-light
coupling.


title: The Boron Buckyball has an Unexpected Th Symmetry

abstract:
  The boron buckyball avoids the high symmetry icosahedral cage structure. The
previously reported Ih symmetric structure is not an energy minimum in the
potential energy surface and exhibits a spontaneous symmetry breaking to yield
a puckered cage with a rare Th symmetry. The HOMO-LUMO gap is twice as large as
the reported value and amounts to 1.94 eV at B3LYP/6-31G(d) level. The valence
orbital structure of boron buckyball is identical to the one in the carbon
analogue.


title:
Metastable state involved resonant tunneling through single InAs/GaAs
  quantum dot

abstract:
  A scheme of resonant tunneling through the metastable state of semiconductor
quantum dot is presented and implemented in the transport study of freestanding
InAs quantum dots grown on GaAs(001) under illumination using conductive atomic
force microscopy. The metastable state is achieved by capturing one
photoexcited Fermi hole in the valence energy level of InAs quantum dot.
Resonant tunneling through single quantum dot can be observed at room
temperature due to the existence of metastable state. The amplitude of
tunneling current depends on the barrier arrangement and the concentration of
photoexcited holes around the quantum dot, but is found steady when the height
of dot varies from 1.8 to 9.9 nm, which are in good agreement with the proposed
model. The experiment demonstrates a solution of room temperature operated
single electron device to amplify the photocurrent by the singularity of
resonant tunneling in epitaxial quantum dot.


title:
The coherent {\it d}-wave superconducting gap in underdoped
  La$_{2-x}$Sr$_{x}$CuO$_4$ as studied by angle-resolved photoemission

abstract:
  We present angle-resolved photoemission spectroscopy (ARPES) data on
moderately underdoped La$_{1.855}$Sr$_{0.145}$CuO$_4$ at temperatures below and
above the superconducting transition temperature. Unlike previous studies of
this material, we observe sharp spectral peaks along the entire underlying
Fermi surface in the superconducting state. These peaks trace out an energy gap
that follows a simple {\it d}-wave form, with a maximum superconducting gap of
14 meV. Our results are consistent with a single gap picture for the cuprates.
Furthermore our data on the even more underdoped sample
La$_{1.895}$Sr$_{0.105}$CuO$_4$ also show sharp spectral peaks, even at the
antinode, with a maximum superconducting gap of 26 meV.


title:
Collective transport in the insulating state of Josephson junction
  arrays

abstract:
  We investigate collective Cooper-pair transport of one- and two-dimensional
Josephson junction arrays in the insulating state. We derive an analytical
expression for the current-voltage characteristic revealing thermally activated
conductivity at small voltages and threshold voltage depinning. The activation
energy and the related depinning voltage represent a dynamic Coulomb barrier
for collective charge transfer over the whole system and scale with the system
size. We show that both quantities are non-monotonic functions of magnetic
field. We propose that formation of the dynamic Coulomb barrier as well as the
size scaling of the activation energy and the depinning threshold voltage, are
consequences of the mutual phase synchronization. We apply the results for
interpretation of experimental data in disordered films near the
superconductor-insulator transition.


title:
2D shift of the centre of gravity of the light beam carrying orbital
  angular momentum, which accompanies reflection from a lossy medium

abstract:
  It is shown that after reflection from a lossy medium the $s$- or
$p$-polarized paraxial light beam carrying the orbital angular momentum suffers
the 2D shift of the beam's centre of gravity relative the geometric optic axis.
The mutually orthogonal components of this shift are expressed through the real
and imaginary parts of the common complex quantity. The features of the 2D
vector, which describes the shift, are analyzed.


title: Unsatisfiable Linear k-CNFs Exist, for every k

abstract:
  We call a CNF formula linear if any two clauses have at most one variable in
common. Let Linear k-SAT be the problem of deciding whether a given linear
k-CNF formula is satisfiable. Here, a k-CNF formula is a CNF formula in which
every clause has size exactly k. It was known that for k >= 3, Linear k-SAT is
NP-complete if and only if an unsatisfiable linear k-CNF formula exists, and
that they do exist for k >= 4. We prove that unsatisfiable linear k-CNF
formulas exist for every k. Let f(k) be the minimum number of clauses in an
unsatisfiable linear k-CNF formula. We show that f(k) is Omega(k2^k) and
O(4^k*k^4), i.e., minimum size unsatisfiable linear k-CNF formulas are
significantly larger than minimum size unsatisfiable k-CNF formulas. Finally,
we prove that, surprisingly, linear k-CNF formulas do not allow for a larger
fraction of clauses to be satisfied than general k-CNF formulas.


title: Evolution of the bursting-layer wave during a Type 1 X-ray burst

abstract:
  In a popular scenario due to Heyl, quasi periodic oscillations (QPOs) which
are seen during type 1 X-ray bursts are produced by giant travelling waves in
neutron-star oceans. Piro and Bildsten have proposed that during the burst
cooling the wave in the bursting layer may convert into a deep crustal
interface wave, which would cut off the visible QPOs. This cut-off would help
explain the magnitude of the QPO frequency drift, which is otherwise
overpredicted by a factor of several in Heyl's scenario. In this paper, we
study the coupling between the bursting layer and the deep ocean. The coupling
turns out to be weak and only a small fraction of the surface-wave energy gets
transferred to that of the crustal-interface wave during the burst. Thus the
crustal-interface wave plays no dynamical role during the burst, and no early
QPO cut-off should occur.


title:
Magnetic Phase Diagram of Spin-1/2 Two-Leg Ladder with Four-Spin Ring
  Exchange

abstract:
  We study the spin-1/2 two-leg Heisenberg ladder with four-spin ring exchanges
under a magnetic field. We introduce an exact duality transformation which is
an extension of the spin-chirality duality developed previously and yields a
new self-dual surface in the parameter space. We then determine the magnetic
phase diagram using the numerical approaches of the density-matrix
renormalization-group and exact diagonalization methods. We demonstrate the
appearance of a magnetization plateau and the Tomonaga-Luttinger liquid with
dominant vector-chirality quasi-long-range order for a wide parameter regime of
strong ring exchange. A "nematic" phase, in which magnons form bound pairs and
the magnon-pairing correlation functions dominate, is also identified.


title: A pentaquark picture of Lambda(1405)

abstract:
  We test a pentaquark model of the negative parity hyperon Lambda(1405). We
use a model where valence four quarks and one antiquark move in a potential
relativistically and interact with each other and themselves through gluon and
NG boson. Fall-apart decay rate of the system is studied and strong model
dependence is pointed out.


title:
Bayesian Galaxy Shape Measurement for Weak Lensing Surveys -I.
  Methodology and a Fast Fitting Algorithm

abstract:
  The principles of measuring the shapes of galaxies by a model-fitting
approach are discussed in the context of shape-measurement for surveys of weak
gravitational lensing. It is argued that such an approach should be optimal,
allowing measurement with maximal signal-to-noise, coupled with estimation of
measurement errors. The distinction between likelihood-based and Bayesian
methods is discussed. Systematic biases in the Bayesian method may be evaluated
as part of the fitting process, and overall such an approach should yield
unbiased shear estimation without requiring external calibration from
simulations. The principal disadvantage of model-fitting for large surveys is
the computational time required, but here an algorithm is presented that
enables large surveys to be analysed in feasible computation times. The method
and algorithm is tested on simulated galaxies from the Shear TEsting Program
(STEP).


title:
Unimodality of ordinary multinomials and maximal probabilities of
  convolution powers of discrete uniform distribution

abstract:
  We establish the unimodality and the asymptotic strong unimodality of the
ordinary multinomials and give their smallest mode leading to the expression of
the maximal probability of convolution powers of the discrete uniform
distribution. We conclude giving the generating functions of the sequence of
generalized ordinary multinomials and for an extension of the sequence of
maximal probabilities for convolution power of discrete uniform distribution.


title: Complex dynamics in a nerve fiber model with periodic coefficients

abstract:
  We deal with the periodic boundary value problem for a second-order nonlinear
ODE which includes the case of the Nagumo type equation $v_{xx} - g v + n(x)
F(v) = 0,$ previously considered by Grindrod and Sleeman and by Chen and Bell
in the study of nerve fiber models. In some recent works we discussed the case
of nonexistence of nontrivial solutions as well as the case in which many
positive periodic solutions may arise, the different situations depending by
threshold parameters related to the weight function $n(x).$ Here we show that
for a step function $n(x)$ (or for small perturbations of it) it is possible to
obtain infinitely many periodic solutions and chaotic dynamics, due to the
presence of a topological horseshoe (according to Kennedy and Yorke).


title:
The quantum Chernoff bound as a measure of distinguishability between
  density matrices: application to qubit and Gaussian states

abstract:
  Hypothesis testing is a fundamental issue in statistical inference and has
been a crucial element in the development of information sciences. The Chernoff
bound gives the minimal Bayesian error probability when discriminating two
hypotheses given a large number of observations. Recently the combined work of
Audenaert et al. [Phys. Rev. Lett. 98, 160501] and Nussbaum and Szkola
  [quant-ph/0607216] has proved the quantum analog of this bound, which applies
when the hypotheses correspond to two quantum states. Based on the quantum
Chernoff bound, we define a physically meaningful distinguishability measure
and its corresponding metric in the space of states; the latter is shown to
coincide with the Wigner-Yanase metric. Along the same lines, we define a
second, more easily implementable, distinguishability measure based on the
error probability of discrimination when the same local measurement is
performed on every copy. We study some general properties of these measures,
including the probability distribution of density matrices, defined via the
volume element induced by the metric, and illustrate their use in the
paradigmatic cases of qubits and Gaussian infinite-dimensional states.


title:
Developments and the preliminary tests of Resistive GEMs manufactured by
  a screen printing technology

abstract:
  We report promising initial results obtained with new resistive-electrode GEM
(RETGEM) detectors manufactured, for the first time, using screen printing
technology. These new detectors allow one to reach gas gains nearly as high as
with ordinary GEM-like detectors with metallic electrodes; however, due to the
high resistivity of its electrodes the RETGEM, in contrast to ordinary
hole-type detectors, has the advantage of being fully spark protected. We
discovered that RETGEMs can operate stably and at high gains in noble gases and
in other badly quenched gases, such as mixtures of noble gases with air and in
pure air; therefore, a wide range of practical applications, including
dosimetry and detection of dangerous gases, is foreseeable. To promote a better
understanding of RETGEM technology some comparative studies were completed with
metallic-electrode thick GEMs. A primary benefit of these new RETGEMs is that
the screen printing technology is easily accessible to many research
laboratories. This accessibility encourages the possibility to manufacture
these GEM-like detectors with the electrode resistivity easily optimized for
particular experimental or practical applications.


title:
Onsager-Machlup theory and work fluctuation theorem for a harmonically
  driven Brownian particle

abstract:
  We extend Tooru-Cohen analysis for nonequilirium steady state(NSS) of a
Brownian particle to nonequilibrium oscillatory state (NOS) of Brownian
particle by considering time dependent external drive protocol. We consider an
unbounded charged Brownian particle in the presence of an oscillating electric
field and prove work fluctuation theorem, which is valid for any initial
distribution and at all times. For harmonically bounded and constantly dragged
Brownian particle considered by Tooru and Cohen, work fluctuation theorem is
valid for any initial condition(also NSS), but only in large time limit. We use
Onsager-Machlup Lagrangian with a constraint to obtain frequency dependent work
distribution function, and describe entropy production rate and properties of
dissipation functions for the present system using Onsager-Machlup functional.


title: Apparent density fluctuations in N-constant ensemble simulations

abstract:
  In computer simulations performed in constant number of particles ensembles,
although the total number of particles N contained in the simulation box does
not fluctuate, hence giving a zero apparent compressibility, there are still
local fluctuations in the number of particles. It is shown herein that these
apparent fluctuations produce a compressibility that can be computed from the
calculated radial distribution function, and which matches to a great accuracy
the compressibility of the fluid for the open system. This statement implies
that the radial distribution function evaluated in simulation of constant
number of particles is identical to that evaluated in the grand canonical
ensemble, for the entire distance range within half-box width. This is
illustrated for the hard sphere and Lennard-Jones fluids and for molecular
models of water. The origin of this apparent fluctuation is that the bulk of
the remaining particles, outside the range over which the distribution function
is calculated, act as a reservoir of particles for those within this range,
thanks to the periodic boundary conditions. The implications on the calculation
of the Kirkwood-Buff integrals are discussed.


title: Sums of products of generalized Fibonacci and Lucas numbers

abstract:
  In this paper, we establish several formulae for sums and alternating sums of
products of generalized Fibonacci and Lucas numbers. In particular, we recover
and extend all results of Z. Cerin and Z. Cerin & G. M. Gianella, more easily.


title: Properties of voids in the Local Volume

abstract:
  Current explanation of the overabundance of dark matter subhalos in the Local
Group (LG) indicates that there maybe a limit on mass of a halo, which can host
a galaxy. This idea can be tested using voids in the distribution of galaxies:
at some level small voids should not contain any (even dwarf) galaxies. We use
observational samples complete to M_B=-12 with distances less than 8 Mpc to
construct the void function (VF): the distribution of sizes of voids empty of
any galaxies. There are ~ 30 voids with sizes ranging from 1 to 5 Mpc. We also
study the distribution of dark matter halos in very high resolution simulations
of the LCDM model. The theoretical VF matches the observations remarkably well
only if we use halos with circular velocities larger than 45 +/- 10 km/s. This
agrees with the Local Group predictions. Small voids look quite similar to heir
giant cousins: the density has a minimum at the center of a void and it
increases as we get closer to the border. Thus, both the Local Group data and
the nearby voids indicate that isolated halos below 45 +/- 10 km/s must not
host galaxies and that small (few Mpc) voids are truly dark.


title: Non-intersecting paths and Hahn orthogonal polynomial ensemble

abstract:
  We compute the bulk limit of the correlation functions for the uniform
measure on lozenge tilings of a hexagon. The limiting determinantal process is
a translation invariant extension of the discrete sine process, which also
describes the ergodic Gibbs measure of an appropriate slope.


title: Structure and clumping in the fast wind of NGC6543

abstract:
  Far-UV spectroscopy from the FUSE satellite is analysed to uniquely probe
spatial structure and clumping in the fast wind of the central star of the
H-rich planetary nebula NGC6543 (HD164963). Time-series data of the unsaturated
PV 1118, 1128 resonance line P Cygni profiles provide a very sensitive
diagnostic of variable wind conditions in the outflow. We report on the
discovery of episodic and recurrent optical depth enhancements in the PV
absorption troughs, with some evidence for a 0.17-day modulation time-scale.
SEI line-synthesis modelling is used to derive physical properties, including
the optical depth evolution of individual `events'. The characteristics of
these features are essentially identical to the `discrete absorption
components' (DACs) commonly seen in the UV lines of massive OB stars. We have
also employed the unified model atmosphere code CMFGEN to explore spectroscopic
signatures of clumping, and report in particular on the clear sensitivity of
the PV lines to the clump volume filling factor. The results presented here
have implications for the downward revision of mass-loss rates in PN central
stars. We conclude that the temporal structures seen in the PV lines of NGC6543
likely have a physical origin that is similar to that operating in massive,
luminous stars, and may be related to near-surface perturbations caused by
stellar pulsation and/or magnetic fields.


title: Randomized algorithm for the k-server problem on decomposable spaces

abstract:
  We study the randomized k-server problem on metric spaces consisting of
widely separated subspaces. We give a method which extends existing algorithms
to larger spaces with the growth rate of the competitive quotients being at
most O(log k). This method yields o(k)-competitive algorithms solving the
randomized k-server problem, for some special underlying metric spaces, e.g.
HSTs of "small" height (but unbounded degree). HSTs are important tools for
probabilistic approximation of metric spaces.


title:
Pulsar kicks by anisotropic neutrino emission from quark matter in
  strong magnetic fields

abstract:
  We discuss a pulsar acceleration mechanism based on asymmetric neutrino
emission from the direct quark Urca process in the interior of proto neutron
stars. The anisotropy is caused by a strong magnetic field which polarises the
spin of the electrons opposite to the field direction. Due to parity violation
the neutrinos and anti-neutrinos leave the star in one direction accelerating
the pulsar. We calculate for varying quark chemical potentials the kick
velocity in dependence of the quark phase temperature and its radius. Ignoring
neutrino quark scattering we find that within a quark phase radius of 10 km and
temperatures larger than 5 MeV kick velocities of 1000km s$^{-1}$ can be
reached very easily. On the other hand taking into account the small neutrino
mean free paths it seems impossible to reach velocities higher than 100km
s$^{-1}$ even when including effects from colour superconductivity where the
neutrino quark interactions are suppressed.


title: Continuous and randomized defensive forecasting: unified view

abstract:
  Defensive forecasting is a method of transforming laws of probability (stated
in game-theoretic terms as strategies for Sceptic) into forecasting algorithms.
There are two known varieties of defensive forecasting: "continuous", in which
Sceptic's moves are assumed to depend on the forecasts in a (semi)continuous
manner and which produces deterministic forecasts, and "randomized", in which
the dependence of Sceptic's moves on the forecasts is arbitrary and
Forecaster's moves are allowed to be randomized. This note shows that the
randomized variety can be obtained from the continuous variety by smearing
Sceptic's moves to make them continuous.


title:
Local effective dynamics of quantum systems: A generalized approach to
  work and heat

abstract:
  By computing the local energy expectation values with respect to some local
measurement basis we show that for any quantum system there are two
fundamentally different contributions: changes in energy that do not alter the
local von Neumann entropy and changes that do. We identify the former as work
and the latter as heat. Since our derivation makes no assumptions on the system
Hamiltonian or its state, the result is valid even for states arbitrarily far
from equilibrium. Examples are discussed ranging from the classical limit to
purely quantum mechanical scenarios, i.e. where the Hamiltonian and the density
operator do not commute.


title:
Three-dimensional solitons and vortices in dipolar Bose-Einstein
  condensates

abstract:
  Three-dimensional solitary and vortex structures in Bose-Einstein condensates
are studied in the framework of Gross-Pitaevskii model including the
simultaneous action of local cubic-quintic nonlinearity and nonlocal
dipole-dipole interactions. Nonlocal interactions are shown to change
significantly the formation threshold and the numbers of atoms confined into
the coherent structures. An appearance of robust high-order ($m=2$)
three-dimensional vortices is revealed.


title: Abundant stable gauge field hair for black holes in anti-de Sitter space

abstract:
  We present new hairy black hole solutions of su(N) Einstein-Yang-Mills theory
(EYM) in asymptotically anti-de Sitter (adS) space. These black holes are
described by N+1 independent parameters, and have N-1 independent gauge field
degrees of freedom. Solutions in which all gauge field functions have no zeros
exist for all N, and for sufficiently large (and negative) cosmological
constant. At least some of these solutions are shown to be stable under
classical, linear, spherically symmetric perturbations. Therefore there is no
upper bound on the amount of stable gauge field hair with which a black hole in
adS can be endowed.


title:
Soliton and black hole solutions of su(N) Einstein-Yang-Mills theory in
  anti-de Sitter space

abstract:
  We present new soliton and hairy black hole solutions of su(N)
Einstein-Yang-Mills theory in asymptotically anti-de Sitter space. These
solutions are described by N+1 independent parameters, and have N-1 gauge field
degrees of freedom. We examine the space of solutions in detail for su(3) and
su(4) solitons and black holes. If the magnitude of the cosmological constant
is sufficiently large, we find solutions where all the gauge field functions
have no zeros. These solutions are of particular interest because we anticipate
that at least some of them will be linearly stable.


title: Buchsteiner loops

abstract:
  Buchsteiner loops are those which satisfy the identity $x\backslash (xy \cdot
z) = (y \cdot zx)/ x$. We show that a Buchsteiner loop modulo its nucleus is an
abelian group of exponent four, and construct an example where the factor
achieves this exponent.


title: Fermionic fields in the pseudoparticle approach

abstract:
  The pseudoparticle approach is a numerical method to compute path integrals
without discretizing spacetime. The basic idea is to consider only those field
configurations, which can be represented as a linear superposition of a small
number of localized building blocks (pseudoparticles), and to replace the
functional integration by an integration over the pseudoparticle degrees of
freedom. In previous papers we have successfully applied the pseudoparticle
approach to SU(2) Yang-Mills theory. In this work we discuss the inclusion of
fermionic fields in the pseudoparticle approach. To test our method, we compute
the phase diagram of the 1+1-dimensional Gross-Neveu model in the large-N limit
as well as the chiral condensate in the crystal phase.


title: Can gravitational collapse sustain singularity-free trapped surfaces?

abstract:
  In singularity generating spacetimes both the out-going and in-going
expansions of null geodesic congruences $\theta ^{+}$ and $\theta ^{-}$ should
become increasingly negative without bound, inside the horizon. This behavior
leads to geodetic incompleteness which in turn predicts the existence of a
singularity. In this work we inquire on whether, in gravitational collapse,
spacetime can sustain singularity-free trapped surfaces, in the sense that such
a spacetime remains geodetically complete. As a test case, we consider a well
known solution of the Einstien Field Equations which is Schwarzschild-like at
large distances and consists of a fluid with a $p=-\rho $ equation of state
near $r=0$. By following both the expansion parameters $\theta ^{+}$ and
$\theta ^{-}$ across the horizon and into the black hole we find that both
$\theta ^{+}$ and $\theta ^{+}\theta ^{-}$ have turning points inside the
trapped region. Further, we find that deep inside the black hole there is a
region $0\leq r<r_{0}$ (that includes the black hole center) which is not
trapped. Thus the trapped region is bounded both from outside and inside. The
spacetime is geodetically complete, a result which violates a condition for
singularity formation. It is inferred that in general if gravitational collapse
were to proceed with a $p=-\rho $ fluid formation, the resulting black hole may
be singularity-free.


title: $G_2$ generating technique for minimal D=5 supergravity and black rings

abstract:
  A solution generating technique is developed for D=5 minimal supergravity
with two commuting Killing vectors based on the $G_2$ U-duality arising in the
reduction of the theory to three dimensions. The target space of the
corresponding 3-dimensional sigma-model is the coset $G_{2(2)}/(SL(2,R)\times
SL(2,R))$. Its isometries constitute the set of solution generating symmetries.
These include two electric and two magnetic Harrison transformations with the
corresponding two pairs of gauge transformations, three $SL(2,R) S$-duality
transformations, and the three gravitational scale, gauge and Ehlers
transformations (altogether 14). We construct a representation of the coset in
terms of $7\times 7$ matrices realizing the automorphisms of split octonions.
Generating a new solution amounts to transforming the coset matrices by
one-parametric subgroups of $G_{2(2)}$ and subsequently solving the dualization
equations. Using this formalism we derive a new charged black ring solution
with two independent parameters of rotation.


title: WIMP Annihilation and Cooling of Neutron Stars

abstract:
  We study the effect of WIMP annihilation on the temperature of a neutron
star. We shall argue that the released energy due to WIMP annihilation inside
the neutron stars, might affect the temperature of stars older than 10 million
years, flattening out the temperature at $\sim 10^4$ K for a typical neutron
star.


title:
On a constructive characterization of a class of trees related to pairs
  of disjoint matchings

abstract:
  For a graph consider the pairs of disjoint matchings which union contains as
many edges as possible, and define a parameter $\alpha$ which eqauls the
cardinality of the largest matching in those pairs. Also, define $\betta$ to be
the cardinality of a maximum matching of the graph.
  We give a constructive characterization of trees which satisfy the
$\alpha$=$\betta$ equality. The proof of our main theorem is based on a new
decomposition algorithm obtained for trees.


title:
A spectroscopic search for non-radial pulsations in the delta Scuti star
  gamma Bootis

abstract:
  High-resolution spectroscopic observations of the rapidly rotating delta
Scuti star gamma Bootis have been carried out on 2005, over 6 consecutive
nights, in order to search for line-profile variability. Time series,
consisting of flux measurements at each wavelength bin across the TiII 4571.917
A line profile as a function of time, have been Fourier analyzed. The results
confirm the early detection reported by Kennelly et al. (1992) of a dominant
periodic component at frequency 21.28 c/d in the observer's frame, probably due
to a high azimuthal order sectorial mode. Moreover, we found other
periodicities at 5.06 c/d, 12.09 c/d, probably present but not secure, and at
11.70 c/d and 18.09 c/d, uncertain. The latter frequency, if present, should be
identifiable as another high azimuthal order sectorial mode and three
additional terms, probably due to low-l modes, as proved by the analysis of the
first three moments of the line. Owing to the short time baseline and the
one-site temporal sampling we consider our results only preliminary but
encouraging for a more extensive multisite campaign. A refinement of the
atmospheric physical parameters of the star has been obtained from our
spectroscopic data and adopted for preliminary computations of evolutionary
models of gamma Bootis.


title:
Adaptive optics imaging and optical spectroscopy of a multiple merger in
  a luminous infrared galaxy

abstract:
  (abridged) We present near-infrared (NIR) adaptive optics imaging obtained
with VLT/NACO and optical spectroscopy from the Southern African Large
Telescope (SALT) of a luminous infrared galaxy (LIRG) IRAS 19115-2124. These
data are combined with archival HST imaging and Spitzer imaging and
spectroscopy, allowing us to study this disturbed interacting/merging galaxy,
dubbed the Bird, in extraordinary detail. In particular, the data reveal a
triple system where the LIRG phenomenon is dominated by the smallest of the
components.
  One nucleus is a regular barred spiral with significant rotation, while
another is highly disturbed with a surface brightness distribution intermediate
to that of disk and bulge systems, and hints of remaining arm/bar structure. We
derive dynamical masses in the range 3-7x10^10 M_solar for both. The third
component appears to be a 1-2x10^10 M_solar mass irregular galaxy. The total
system exhibits HII galaxy-like optical line ratios and strengths, and no
evidence for AGN activity is found from optical or mid-infrared data. The star
formation rate is estimated to be 190 M_solar/yr. We search for SNe, super star
clusters, and detect 100-300 km/s outflowing gas from the Bird. Overall, the
Bird shows kinematic, dynamical, and emission line properties typical for cool
ultra luminous IR galaxies. However, the interesting features setting it apart
for future studies are its triple merger nature, and the location of its star
formation peak - the strongest star formation does not come from the two major
K-band nuclei, but from the third irregular component. Aided by simulations, we
discuss scenarios where the irregular component is on its first high-speed
encounter with the more massive components.


title: A Note On The Kadison-Singer Problem

abstract:
  Let H be a separable Hilbert space with a fixed orthonormal basis (e_n),
n>=1, and B(H) be the full von Neumann algebra of the bounded linear operators
T: H -> H. Identifying l^\infty = C(\beta N) with the diagonal operators, we
consider C(\beta N) as a subalgebra of B(H). For each t in \beta N, let
[\delta_t] be the set of the states of B(H) that extend the Dirac measure
\delta_t. Our main result shows that, for each t in \beta N, this set either
lies in a finite dimensional subspace of B(H)* or else it must contain a
homeomorphic copy of \beta N.


title: Objective and subjective time in anthropic reasoning

abstract:
  The original formulation of the (weak) anthropic principle was prompted by a
question about objective time at a macroscopic level, namely the age of the
universe when ``anthropic'' observers such as ourselves would be most likely to
emerge. Theoretical interpretation of what one observes requires the theory to
indicate what is expected, which will commonly depend on where, and
particularly when, the observation can be expected to occur. In response to the
question of where and when, the original version of the anthropic principle
proposed an {it a priori} probability weighting proportional to the number of
``anthropic'' observers present. The present discussion takes up the question
of the time unit characterising the biological clock controlling our subjective
internal time, using a revised alternative to a line of argument due to Press,
who postulated that animal size is limited by the brittleness of bone. On the
basis of a static support condition depending on the tensile strength of flesh
rather than bone, it is reasoned here that our size should be subject to a
limit inversely proportional to the terrestrial gravitation field g, which is
itself found to be proportional (with a factor given by the 5/2 power of the
fine structure constant) to the gravitational coupling constant.This provides
an animal size limit that will in all cases be of the order of a thousandth of
the maximum mountain height, which will itself be of the order of a thousandth
of the planetary radius. The upshot, via the (strong) anthropic principle, is
that the need for brains, and therefore planets, that are large in terms of
baryon number may be what explains the weakness of gravity relative to
electromagnetism.


title:
First Order Calculation of the Inclusive Cross Section pp to ZZ by
  Graviton Exchange in Large Extra Dimensions

abstract:
  We calculate the inclusive cross section of double Z-boson production within
large extra dimensions at the Large Hadron Collider (LHC). Using perturbatively
quantized gravity in the ADD model we perform a first order calculation of the
graviton mediated contribution to the pp to ZZ cross section. At low energies
(e.g. Tevatron) this additional contribution is very small, making it virtually
unobservable, for a fundamental mass scale above 2500 GeV. At LHC energies
however, the calculation indicates that the ZZ-production rate within the ADD
model should differ significantly from the Standard Model if the new
fundamental mass scale would be below 15000 GeV. A comparison with the observed
production rate at the LHC might therefore provide direct hints on the number
and structure of the extra dimensions.


title:
Testing for change points in time series models and limiting theorems
  for NED sequences

abstract:
  This paper first establishes a strong law of large numbers and a strong
invariance principle for forward and backward sums of near-epoch dependent
sequences. Using these limiting theorems, we develop a general asymptotic
theory on the Wald test for change points in a general class of time series
models under the no change-point hypothesis. As an application, we verify our
assumptions for the long-memory fractional ARIMA model.


title:
Observation of the 'head-tail' effect in nuclear recoils of low-energy
  neutrons

abstract:
  Directional detection of dark matter can provide unambiguous observation of
dark matter interactions even in the presence of background. This article
presents an experimental method to measure the direction tag ("head-tail") of
the dark matter wind by detecting the scintillation light created by the
elastic nuclear recoils in the scattering of dark matter particles with the
detector material. The technique is demonstrated by tagging the direction of
the nuclear recoils created in the scattering of low-energy neutrons with CF4
in a low-pressure time-projection chamber that is developed by the DMTPC
collaboration. The measurement of the decreasing ionization rate along the
recoil trajectory provides the direction tag of the incoming neutrons, and
proves that the "head-tail" effect can be observed.


title:
Singularities of quadratic differentials and extremal Teichm\"{u}ller
  mappings defined by Dehn twists

abstract:
  Let $S$ be a Riemann surface of type $(p,n)$ with $3p-3+n>0$. Let $\omega$ be
a pseudo-Anosov map of $S$ that is obtained from Dehn twists along two families
$\{A,B\}$ of simple closed geodesics that fill $S$. Then $\omega$ can be
realized as an extremal Teichm\"{u}ller mapping on a surface of type $(p,n)$
which is also denoted by $S$. Let $\phi$ be the corresponding holomorphic
quadratic differential on $S$. In this paper, we compare the locations of some
distinguished points on $S$ in the $\phi$-flat metric to their locations with
respect to the complete hyperbolic metric. More precisely, we show that all
possible non-puncture zeros of $\phi$ must stay away from all closures of once
punctured disk components of $S\backslash \{A, B\}$, and the closure of each
disk component of $S\backslash \{A, B\}$ contains at most one zero of $\phi$.
As a consequence of the result, we assert that the number of distinct zeros and
poles of $\phi$ is less than or equal to the number of components of
$S\backslash \{A, B\}$.


title: Searching for a Pulsar in SN1987A

abstract:
  SN 1987A offered a unique opportunity to detect a pulsar at the very
beginning of its life and to study its early evolution. Despite many searches
at radio and optical wavelengths, no pulsar has yet been detected. Details of a
recent search using the Parkes radio telescope are given. Limits on the X-ray,
optical and radio luminosity of a point source at the centre of SN 1987A place
limits on the properties of a central neutron star. However, neither these nor
the pulsar limits preclude the presence of a relatively slowly rotating neutron
star (P >~ 100 ms) with a moderate surface dipole magnetic field in SN 1987A.
Galactic studies suggest that a significant fraction of pulsars are born with
parameters in this range. In view of this, continued searches for a pulsar in
SN 1987A are certainly justified.


title:
Accumulated prediction errors, information criteria and optimal
  forecasting for autoregressive time series

abstract:
  The predictive capability of a modification of Rissanen's accumulated
prediction error (APE) criterion, APE$_{\delta_n}$, is investigated in
infinite-order autoregressive (AR($\infty$)) models. Instead of accumulating
squares of sequential prediction errors from the beginning, APE$_{\delta_n}$ is
obtained by summing these squared errors from stage $n\delta_n$, where $n$ is
the sample size and $1/n\leq \delta_n\leq 1-(1/n)$ may depend on $n$. Under
certain regularity conditions, an asymptotic expression is derived for the
mean-squared prediction error (MSPE) of an AR predictor with order determined
by APE$_{\delta_n}$. This expression shows that the prediction performance of
APE$_{\delta_n}$ can vary dramatically depending on the choice of $\delta_n$.
Another interesting finding is that when $\delta_n$ approaches 1 at a certain
rate, APE$_{\delta_n}$ can achieve asymptotic efficiency in most practical
situations. An asymptotic equivalence between APE$_{\delta_n}$ and an
information criterion with a suitable penalty term is also established from the
MSPE point of view. This offers new perspectives for understanding the
information and prediction-based model selection criteria. Finally, we provide
the first asymptotic efficiency result for the case when the underlying
AR($\infty$) model is allowed to degenerate to a finite autoregression.


title:
Universal observation of multiple order parameters in cuprate
  superconductors

abstract:
  The temperature dependence of the London penetration depth \lambda was
measured for an untwined single crystal of YBa_2Cu_3O_{7-\delta} along the
three principal crystallographic directions (a, b, and c). Both in-plane
components (\lambda_a and \lambda_b) show an inflection point in their
temperature dependence which is absent in the component along the c-direction
(\lambda_c). The data provide convincing evidence that the in-plane
superconducting order parameter is a mixture of s+d-wave symmetry whereas it is
exclusively s-wave along the c-direction. In conjunction with previous results
it is concluded that coupled s+d-order parameters are universal and intrinsic
to cuprate superconductors.


title: Resummation and the semiclassical theory of spectral statistics

abstract:
  We address the question as to why, in the semiclassical limit, classically
chaotic systems generically exhibit universal quantum spectral statistics
coincident with those of Random Matrix Theory. To do so, we use a semiclassical
resummation formalism that explicitly preserves the unitarity of the quantum
time evolution by incorporating duality relations between short and long
classical orbits. This allows us to obtain both the non-oscillatory and the
oscillatory contributions to spectral correlation functions within a unified
framework, thus overcoming a significant problem in previous approaches. In
addition, our results extend beyond the universal regime to describe the
system-specific approach to the semiclassical limit.


title: On the geometric dependence of Riemannian Sobolev best constants

abstract:
  We concerns here with the continuity on the geometry of the second Riemannian
L^p-Sobolev best constant B_0(p,g) associated to the AB program. Precisely, for
1 <= p <= 2, we prove that B_0(p,g) depends continuously on g in the
C^2-topology. Moreover, this topology is sharp for p = 2. From this discussion,
we deduce some existence and C^0-compactness results on extremal functions.


title: Online Learning in Discrete Hidden Markov Models

abstract:
  We present and analyse three online algorithms for learning in discrete
Hidden Markov Models (HMMs) and compare them with the Baldi-Chauvin Algorithm.
Using the Kullback-Leibler divergence as a measure of generalisation error we
draw learning curves in simplified situations. The performance for learning
drifting concepts of one of the presented algorithms is analysed and compared
with the Baldi-Chauvin algorithm in the same situations. A brief discussion
about learning and symmetry breaking based on our results is also presented.


title: Surface charge algebra in gauge theories and thermodynamic integrability

abstract:
  Surface charges and their algebra in interacting Lagrangian gauge field
theories are investigated by using techniques from the variational calculus. In
the case of exact solutions and symmetries, the surface charges are interpreted
as a Pfaff system. Integrability is governed by Frobenius' theorem and the
charges associated with the derived symmetry algebra are shown to vanish. In
the asymptotic context, we provide a generalized covariant derivation of the
result that the representation of the asymptotic symmetry algebra through
charges may be centrally extended. Finally, we make contact with Hamiltonian
and with covariant phase space methods.


title:
Gemini GMOS/IFU spectroscopy of NGC 1569 - I: Mapping the properties of
  a young star cluster and its environment

abstract:
  [Abridged] We present Gemini-North GMOS/IFU observations of a young star
cluster (cluster 10) and its environment near the centre of the dwarf irregular
starburst galaxy NGC 1569. This forms part of a larger and on-going study of
the formation and collimation mechanisms of galactic winds, including three
additional IFU pointings in NGC 1569 covering the base of the galactic wind
which are analysed in a companion paper. The good spatial- and
spectral-resolution of these GMOS/IFU observations, covering 4740-6860 A, allow
us to probe the interactions between clusters and their environments on small
scales. Combining our GMOS spectrum with HST imaging, we find that cluster 10
is composed of two very close components with ages of 5-7 Myr and <5 Myr, and a
combined mass of 7 +/- 5 x 10^3 Msun.
  A detailed analysis of the H_alpha emission line profile shapes across the
whole field-of-view shows them to be composed of a bright narrow feature
(intrinsic FWHM ~ 50 km/s) superimposed on a fainter broad component (FWHM <
300 km/s). By mapping the properties of each individual component, we
investigate the small-scale structure and properties of the ionized ISM,
including reddening, excitation and electron densities, and for the first time
find spatial correlations between the line component properties. We discuss in
detail the possible mechanisms that could give rise to the two components and
these correlations, and conclude that the most likely explanation for the broad
emission is that it is produced in a turbulent mixing layer on the surface of
the cool gas clumps embedded within the hot, fast-flowing cluster winds. We
conclude we are sampling well within the outer bounding shocks of the expanding
superbubbles and within the outflow 'energy injection zone'.


title: Wishart distributions for decomposable graphs

abstract:
  When considering a graphical Gaussian model ${\mathcal{N}}_G$ Markov with
respect to a decomposable graph $G$, the parameter space of interest for the
precision parameter is the cone $P_G$ of positive definite matrices with fixed
zeros corresponding to the missing edges of $G$. The parameter space for the
scale parameter of ${\mathcal{N}}_G$ is the cone $Q_G$, dual to $P_G$, of
incomplete matrices with submatrices corresponding to the cliques of $G$ being
positive definite. In this paper we construct on the cones $Q_G$ and $P_G$ two
families of Wishart distributions, namely the Type I and Type II Wisharts. They
can be viewed as generalizations of the hyper Wishart and the inverse of the
hyper inverse Wishart as defined by Dawid and Lauritzen [Ann. Statist. 21
(1993) 1272--1317]. We show that the Type I and II Wisharts have properties
similar to those of the hyper and hyper inverse Wishart. Indeed, the inverse of
the Type II Wishart forms a conjugate family of priors for the covariance
parameter of the graphical Gaussian model and is strong directed hyper Markov
for every direction given to the graph by a perfect order of its cliques, while
the Type I Wishart is weak hyper Markov. Moreover, the inverse Type II Wishart
as a conjugate family presents the advantage of having a multidimensional shape
parameter, thus offering flexibility for the choice of a prior.


title:
Embedding spacetime via a geodesically equivalent metric of Euclidean
  signature

abstract:
  Starting from the equations of motion in a 1 + 1 static, diagonal, Lorentzian
spacetime, such as the Schwarzschild radial line element, I find another
metric, but with Euclidean signature, which produces the same geodesics x(t).
This geodesically equivalent, or dual, metric can be embedded in ordinary
Euclidean space. On the embedded surface freely falling particles move on the
shortest path. Thus one can visualize how acceleration in a gravitational field
is explained by particles moving freely in a curved spacetime. Freedom in the
dual metric allows us to display, with substantial curvature, even the weak
gravity of our Earth. This may provide a nice pedagogical tool for elementary
lectures on general relativity. I also study extensions of the dual metric
scheme to higher dimensions. In an addendum I extend the analysis concerning
the shape of an embedding of the dual spacetime of a line through a planet of
constant proper density.


title: Pluto: A Monte Carlo Simulation Tool for Hadronic Physics

abstract:
  Pluto is a Monte-Carlo event generator designed for hadronic interactions
from Pion production threshold to intermediate energies of a few GeV per
nucleon, as well as for studies of heavy ion reactions. This report gives an
overview of the design of the package, the included models and the user
interface.


title:
Some explicit identities associated with positive self-similar Markov
  processes

abstract:
  We consider some special classes of L\'evy processes with no gaussian
component whose L\'evy measure is of the type $\pi(dx)=e^{\gamma x}\nu(e^x-1)
dx$, where $\nu$ is the density of the stable L\'evy measure and $\gamma$ is a
positive parameter which depends on its characteristics. These processes were
introduced in \cite{CC} as the underlying L\'evy processes in the Lamperti
representation of conditioned stable L\'evy processes. In this paper, we
compute explicitly the law of these L\'evy processes at their first exit time
from a finite or semi-finite interval, the law of their exponential functional
and the first hitting time probability of a pair of points.


title: Co-operativity in neurons and the role of noise in brain

abstract:
  In view of some recent results in case of the dopaminergic neurons exhibiting
long range correlations in VTA of the limbic brain we are interested to find
out whether any stochastic nonlinear response may be reproducible in the nano
scales usimg the results of quantum mechanics. We have developed a scheme to
investigate this situation in this paper by taking into consideration the
Schrodinger equation (SE) in an arbitrary manifold with a metric, which is in
some sense a special case of the heat kernel equation. The special case of this
heat kernel equation is the diffusion equation, which may reproduce some key
phenomena of the neural activities. We make a dual equivalent circuit model of
SE and incorporate non commutativity and noise inside the circuit scheme. The
behaviour of the circuit elements with interesting limits are investigated. The
most bizarre part is the long range response of the model by dint of the
Central Limit Theorem, which is responsible for coherent behaviour of a large
assembly of neurons.


title: A centimetre-wave excess over free-free emission in planetary nebulae

abstract:
  We report a centimetre-wave (cm-wave, 5-31GHz) excess over free-free emission
in PNe. Accurate 31 and 250GHz measurements show that the 31GHz flux densities
in our sample are systematically higher than the level of optically thin
free-free continuum extrapolated from 250GHz. The 31GHz excess is observed,
within one standard deviation, in all 18 PNe with reliable 31 and 250GHz data,
and is significant in 9 PNe. The only exception is the peculiar object M2-9,
whose radio spectrum is that of an optically thick stellar wind. On average the
fraction of non-free-free emission represents 51% of the total flux density at
31GHz, with a scatter of 11%. The average 31-250GHz spectral index of our
sample is <alpha_{31}^{250}> = -0.43+-0.03 (in flux density, with a scatter of
0.14). The 31--250 GHz drop is reminiscent of the anomalous foreground observed
in the diffuse ISM by CMB anisotropy experiments. The 5--31 GHz spectral
indices are consistent with both flat spectra and spinning dust emissivities,
given the 10% calibration uncertainty of the comparison 5GHz data. But a
detailed study of the objects with the largest cm-excess, including the low
frequency data available in the literature, shows that present spinning dust
models cannot alone explain the cm-excess in PNe. Although we have no
definitive interpretation of our data, the least implausible explanation
involves a synchrotron component absorbed by a cold nebular screen. We give
flux densities for 37 objects at 31GHz, and for 26 objects at 250GHz.


title: Non-Abelian Vortices on the Torus

abstract:
  We study periodic arrays of non-Abelian vortices in an $SU(N) \times U(1)$
gauge theory with $N_f$ flavors of fundamental matter multiplets. We carefully
discuss the corresponding twisted boundary conditions on the torus and propose
an ansatz to solve the first order Bogomolnyi equations which we find by
looking to a bound of the energy. We solve the equations numerically and
construct explicit vortex solutions.


title: Orbit determination for next generation space clocks

abstract:
  Over the last decade of the 20th century and the first few years of the 21st,
the uncertainty of atomic clocks has decreased by about two orders of
magnitude, passing from the low 10^-14 to below 10^-16, in relative frequency .
Space applications in fundamental physics, geodesy, time/frequency metrology,
navigation etc... are among the most promising for this new generation of
clocks. Onboard terrestrial or solar system satellites, their exceptional
frequency stability and accuracy makes them a prime tool to test the
fundamental laws of nature, and to study gravitational potentials and their
evolution.
  In this paper, we study in more detail the requirements on orbitography
compatible with operation of next generation space clocks at the required
uncertainty based on a completely relativistic model. Using the ACES (Atomic
Clock Ensemble in Space) mission as an example, we show that the required
accuracy goal can be reached with relatively modest constraints on the
orbitography of the space clock, much less stringent than expected from "naive"
estimates. Our results are generic to all space clocks and represent a
significant step towards the generalised use of next generation space clocks in
fundamental physics, geodesy, and time/frequency metrology.


title: Two electron entanglement enhancement by an inelastic scattering process

abstract:
  In order to assess inelastic effects on two fermion entanglement production,
we address an exactly solvable two-particle scattering problem where the target
is an excitable scatterer. Useful entanglement, as measured by the two particle
concurrence, is obtained from post-selection of oppositely scattered particle
states. The $S$ matrix formalism is generalized in order to address non-unitary
evolution in the propagating channels. We find the striking result that
inelasticity can actually increase concurrence as compared to the elastic case
by increasing the uncertainty of the single particle subspace. Concurrence
zeros are controlled by either single particle resonance energies or total
reflection conditions that ascertain precisely one of the electron states.
Concurrence minima also occur and are controlled by entangled resonance
situations were the electron becomes entangled with the scatterer, and thus
does not give up full information of its state. In this model, exciting the
scatterer can never fully destroy phase coherence due to an intrinsic limit to
the probability of inelastic events.


title:
Vector and axialvector mesons at nonzero temperature within a gauged
  linear sigma model

abstract:
  We consider vector and axialvector mesons in the framework of a gauged linear
sigma model with chiral $U(N_f)_R \times U(N_f)_L$ symmetry. For $N_f=2$, we
investigate the behavior of the chiral condensate and the meson masses as a
function of temperature by solving a system of coupled Dyson-Schwinger
equations derived via the 2PI formalism in double-bubble approximation. We find
that the inclusion of vector and axialvector mesons tends to sharpen the chiral
transition. Within our approximation scheme, the mass of the $\rho$ meson
increases by about 100 MeV towards the chiral transition.


title: The circumbinary disk of HD 98800 B: Evidence for disk warping

abstract:
  The quadruple young stellar system HD 98800 consists of two spectroscopic
binary pairs with a circumbinary disk around the B component. Recent work by
Boden and collaborators using infrared interferometry and radial velocity data
resulted in a determination of the physical orbit for HD 98800 B. We use the
resulting inclination of the binary and the measured extinction toward the B
component stars to constrain the distribution of circumbinary material.
Although a standard optically and geometrically thick disk model can reproduce
the spectral energy distribution, it can not account for the observed
extinction if the binary and the disk are co-planar. We next constructed a
dynamical model to investigate the influence of the A component, which is not
in the Ba-Bb orbital plane, on the B disk. We find that these interactions have
a substantial impact on the inclination of the B circumbinary disk with respect
to the Ba-Bb orbital plane. The resulting warp would be sufficient to place
material into the line of sight and the non-coplanar disk orientation may also
cause the upper layers of the disk to intersect the line of sight if the disk
is geometrically thick. These simulations also support that the dynamics of the
Ba-Bb orbit clear the inner region to a radius of ~3 AU. We then discuss
whether the somewhat unusual properties of the HD 98800 B disk are consistent
with material remnant from the star formation process or with more recent
creation by collisions from larger bodies.


title: On the capability of finite groups of class two and prime exponent

abstract:
  We consider the capability of $p$-groups of class two and odd prime exponent.
The question of capability is shown to be equivalent to a statement about
vector spaces and linear transformations, and using the equivalence we give
proofs of some old results and several new ones. In particular, we establish a
number of new necessary and new sufficient conditions for capability, including
a sufficient condition based only on the ranks of $G/Z(G)$ and $[G,G]$.
Finally, we characterise the capable groups among the 5-generated groups in
this class.


title: Towards mirror symmetry \`a la SYZ for generalized Calabi-Yau manifolds

abstract:
  Fibrations of flux backgrounds by supersymmetric cycles are investigated. For
an internal six-manifold M with static SU(2) structure and mirror \hat{M}, it
is argued that the product M x \hat{M} is doubly fibered by supersymmetric
three-tori, with both sets of fibers transverse to M and \hat{M}. The mirror
map is then realized by T-dualizing the fibers. Mirror-symmetric properties of
the fluxes, both geometric and non-geometric, are shown to agree with previous
conjectures based on the requirement of mirror symmetry for Killing
prepotentials. The fibers are conjectured to be destabilized by fluxes on
generic SU(3)xSU(3) backgrounds, though they may survive at type-jumping
points. T-dualizing the surviving fibers ensures the exchange of pure spinors
under mirror symmetry.


title: QCD factorization approach for rare $\bar B^0\to D^*\gamma$ decay

abstract:
  We present the estimate of the branching ratio for the rare decay $\bar
B^0\to D^*\gamma$. We use QCD factorization approach in order to compute the
amplitude of the process. The calculation is carried out with the leading order
accuracy. % Our consideration is based on the % factorization for the amplitude
of the process which % has been derived with the leading order accuracy. The
appearing non-perturbative matrix elements have been estimated using the
large$-N_c$ limit and QCD sum rule approach. We obtained that $\mathcal{B}(\bar
B^0\to D^*\gamma)\simeq 1.52\times 10^{-7}$. Such value of the branching
fraction is too small in order to be measured at present experiments.


title: F-thresholds, tight closure, integral closure, and multiplicity bounds

abstract:
  The F-threshold $c^J(\a)$ of an ideal $\a$ with respect to the ideal $J$ is a
positive characteristic invariant obtained by comparing the powers of $\a$ with
the Frobenius powers of $J$. We show that under mild assumptions, we can detect
the containment in the integral closure or the tight closure of a parameter
ideal using F-thresholds. We formulate a conjecture bounding $c^J(\a)$ in terms
of the multiplicities $e(\a)$ and $e(J)$, when $\a$ and $J$ are
zero-dimensional ideals, and $J$ is generated by a system of parameters. We
prove the conjecture when $J$ is a monomial ideal in a polynomial ring, and
also when $\a$ and $J$ are generated by homogeneous systems of parameters in a
Cohen-Macaulay graded $k$-algebra.


title:
Key Agreement and Authentication Schemes Using Non-Commutative
  Semigroups

abstract:
  We give a new two-pass authentication scheme, whichis a generalisation of an
authentication scheme of Sibert-Dehornoy-Girault based on the Diffie-Hellman
conjugacy problem. Compared to the above scheme, for some parameters it is more
efficient with respect to multiplications. We sketch a proof that our
authentication scheme is secure. We give a new key agreement protocols.


title:
Understanding entanglement as resource: locally distinguishing
  unextendible product bases

abstract:
  It is known that the states in an unextendible product basis (UPB) cannot be
distinguished perfectly when the parties are restricted to local operations and
classical communication (LOCC). Previous discussions of such bases have left
open the following question: What entanglement resources are necessary and/or
sufficient for this task to be possible with LOCC? In this paper, I present
protocols which use entanglement more efficiently than teleportation to
distinguish certain classes of UPB's. The ideas underlying my approach to this
problem offer rather general insight into why entanglement is useful for such
tasks.


title: On the AAGL Protocol

abstract:
  Recently the AAGL (Anshel-Anshel-Goldfeld-Lemieux) has been proposed which
can be used for RFID tags. We give algorithms for the problem (we call the
MSCSPv) on which the security of the AAGL protocol is based upon. Hence we give
various attacks for general parameters on the recent AAGL protocol proposed.
One of our attacks is a deterministic algorithm which has space complexity and
time complexity both atleast exponentialin the worst case. In a better case
using a probabilistic algorithm the time complexity canbe
O(|XSS(ui')^L5*(n^(1+e)) and the space complexity can be O(|XSS(ui')|^L6),
where the element ui' is part of a public key, n is the index of braid group,
XSS is a summit type set and e is a constant in a limit. The above shows the
AAGL protocol is potentially not significantly more secure as using key
agreement protocols based on the conjugacy problem such as the AAG
(Anshel-Anshel-Goldfeld) protocol because both protocols can be broken with
complexity which do not significantly differ. We think our attacks can be
improved.


title: A Numerical Unitarity Formalism for Evaluating One-Loop Amplitudes

abstract:
  Recent progress in unitarity techniques for one-loop scattering amplitudes
makes a numerical implementation of this method possible. We present a
4-dimensional unitarity method for calculating the cut-constructible part of
amplitudes and implement the method in a numerical procedure. Our technique can
be applied to any one-loop scattering amplitude and offers the possibility that
one-loop calculations can be performed in an automatic fashion, as tree-level
amplitudes are currently done. Instead of individual Feynman diagrams, the
ingredients for our one-loop evaluation are tree-level amplitudes, which are
often already known. To study the practicality of this method we evaluate the
cut-constructible part of the 4, 5 and 6 gluon one-loop amplitudes numerically,
using the analytically known 4, 5 and 6 gluon tree-level amplitudes.
Comparisons with analytic answers are performed to ascertain the numerical
accuracy of the method.


title: X-ray flaring from the young stars in CygnusOB2

abstract:
  Aims: We characterize individual and ensemble properties of X-ray flares from
stars in the CygOB2 and ONC star-forming regions. Method: We analyzed X-ray
lightcurves of 1003 CygOB2 sources observed with Chandra for 100 ksec and of
1616 ONC sources detected in the ``Chandra Orion Ultra-deep Project'' 850 ksec
observation. We employed a binning-free maximum likelihood method to segment
the light-curves into intervals of constants signal and identified flares on
the basis of both the amplitude and the time-derivative of the source
luminosity. We then derived and compared the flare frequency and energy
distribution of CygOB2 and ONC sources. The effect of the length of the
observation on these results was investigated by repeating the statistical
analysis on five 100 ksec-long segments extracted from the ONC data. Results:
We detected 147 and 954 flares from the CygOB2 and ONC sources, respectively.
The flares in CygOB2 have decay times ranging from ~0.5 to about 10 hours. The
flare energy distributions of all considered flare samples are described at
high energies well by a power law with index alpha=-(2.1+-0.1). At low
energies, the distributions flatten, probably because of detection
incompleteness. We derived average flare frequencies as a function of flare
energy. The flare frequency is seen to depend on the source's intrinsic X-ray
luminosity, but its determination is affected by the length of the observation.
The slope of the high-energy tail of the energy distribution is, however,
affected little. A comparison of CygOB2 and ONC sources, accounting for
observational biases, shows that the two populations, known to have similar
X-ray emission levels, have very similar flare activity.


title:
Spitzer Spectra of a 10 mJy Galaxy Sample and the Star Formation Rate in
  the Local Universe

abstract:
  A complete flux-limited sample of 50 galaxies is presented having
f_{\nu}(24um) > 10mJy, chosen from a survey with the Multiband Imaging
Photometer on Spitzer (MIPS) of 8.2 deg^{2} within the NOAO Deep Wide-Field
Survey region in Bootes (NDWFS). Spectra obtained with the low-resolution
modules of the Infrared Spectrograph on Spitzer (IRS) are described for 36
galaxies within this sample; 25 show strong PAH emission features
characteristic of starbursts, and 11 show silicate absorption or emission,
emission lines, or featureless spectra characteristic of AGN. Infrared or
optical spectral classifications are available for 48 of the entire sample of
50; 33 galaxies are classified as starbursts and 15 as AGN. (There are an
additional 19 Galactic stars with f_{\nu}(24um) > 10mJy in the survey area.)
Using a relation between 7.7um PAH luminosity and star formation rate derived
from previous IRS observations of starbursts, the star formation rate per unit
volume of the local universe (SFRD) is determined from the complete sample and
is found to be 0.008 \mdot Mpc^{-3}. Individual sources in the sample have star
formation rates from 0.14 to 160 \mdot. The derived value for the local SFRD is
about half that of the local SFRD deduced from bolometric luminosities of the
IRAS 60um Bright Galaxy Sample, with the deficiency being at lower luminosities
and arising primarily from the small number of low luminosity sources in the 10
mJy sample. The agreement for higher luminosities confirms the validity of
using the 7.7um PAH feature as a measure of SFRD in the high redshift universe,
where this is often the only indicator available for faint sources.


title: Hydrodynamics of self-propelled hard rods

abstract:
  Motivated by recent simulations and by experiments on aggregation of gliding
bacteria, we study a model of the collective dynamics of self-propelled hard
rods on a substrate in two dimensions. The rods have finite size, interact via
excluded volume and their dynamics is overdamped by the interaction with the
substrate. Starting from a microscopic model with non-thermal noise sources, a
continuum description of the system is derived. The hydrodynamic equations are
then used to characterize the possible steady states of the systems and their
stability as a function of the particles packing fraction and the speed of self
propulsion.


title: Black strings in AdS_5

abstract:
  We present non-extremal magnetic black string solutions in five-dimensional
gauged supergravity. The conformal infinity is the product of time and S^1xS_h,
where S_h denotes a compact Riemann surface of genus h. The construction is
based on both analytical and numerical techniques. We compute the holographic
stress tensor, the Euclidean action and the conserved charges of the solutions
and show that the latter satisfy a Smarr-type formula. The phase structure is
determined in the canonical ensemble, and it is shown that there is a first
order phase transition from small to large black strings, which disappears
above a certain critical magnetic charge that is obtained numerically. For
another particular value of the magnetic charge, that corresponds to a twisting
of the dual super Yang-Mills theory, the conformal anomalies coming from the
background curvature and those arising from the coupling to external gauge
fields exactly cancel. We also obtain supersymmetric solutions describing waves
propagating on extremal BPS magnetic black strings, and show that they possess
a Siklos-Virasoro reparametrization invariance.


title:
Metrics and isospectral partners for the most generic cubic PT-symmetric
  non-Hermitian Hamiltonian

abstract:
  We investigate properties of the most general PT-symmetric non-Hermitian
Hamiltonian of cubic order in the annihilation and creation operators as a ten
parameter family. For various choices of the parameters we systematically
construct an exact expression for a metric operator and an isospectral
Hermitian counterpart in the same similarity class by exploiting the
isomorphism between operator and Moyal products. We elaborate on the subtleties
of this approach. For special choices of the ten parameters the Hamiltonian
reduces to various models previously studied, such as to the complex cubic
potential, the so-called Swanson Hamiltonian or the transformed version of the
from below unbounded quartic -x^4-potential. In addition, it also reduces to
various models not considered in the present context, namely the single site
lattice Reggeon model and a transformed version of the massive sextic
x^6-potential, which plays an important role as a toy modelto identify theories
with vanishing cosmological constant.


title: Unquenching Effects on the Coefficients of the L\"uscher-Weisz Action

abstract:
  The effects of unquenching on the perturbative improvement coefficients in
the Symanzik action are computed within the framework of L\"uscher-Weisz
on-shell improvement. We find that the effects of quark loops are surprisingly
large, and their omission may well explain the scaling violations observed in
some unquenched studies.


title: PT-symmetry and Integrability

abstract:
  We briefly explain some simple arguments based on pseudo Hermiticity,
supersymmetry and PT-symmetry which explain the reality of the spectrum of some
non-Hermitian Hamiltonians. Subsequently we employ PT-symmetry as a guiding
principle to construct deformations of some integrable systems, the
Calogero-Moser-Sutherland model and the Korteweg deVries equation. Some
properties of these models are discussed.


title: On rectangular diagrams, Legendrian knots and transverse knots

abstract:
  A correspondence is studied by H. Matsuda between front projections of
Legendrian links in the standard contact structure for 3-space and rectangular
diagrams. In this paper, we introduce braided rectangular diagrams, and study a
relationship with Legendrian links in the standard contact structure for
3-space. We show Alexander and Markov Theorems for Legendrian links in 3-space.


title:
Classical Integrable N=1 and $N= 2$ Super Sinh-Gordon Models with Jump
  Defects

abstract:
  The structure of integrable field theories in the presence of jump defects is
discussed in terms of boundary functions under the Lagrangian formalism.
Explicit examples of bosonic and fermionic theories are considered. In
particular, the boundary functions for the N=1 and N=2 super sinh-Gordon models
are constructed and shown to generate the Backlund transformations for its
soliton solutions. As a new and interesting example, a solution with an
incoming boson and an outgoing fermion for the N=1 case is presented. The
resulting integrable models are shown to be invariant under supersymmetric
transformation.


title: Charged Impurity Scattering in Graphene

abstract:
  Since the experimental realization of graphene1, extensive theoretical work
has focused on short-range disorder2-5, ''ripples''6, 7, or charged
impurities2, 3, 8-13 to explain the conductivity as a function of carrier
density sigma_(n)[1,14-18], and its minimum value sigma_min near twice the
conductance quantum 4e2/h[14, 15, 19, 20]. Here we vary the density of charged
impurities nimp on clean graphene21 by deposition of potassium in ultra high
vacuum. At non-zero carrier density, charged impurity scattering produces the
ubiquitously observed1, 14-18 linear sigma_(n) with the theoretically-predicted
magnitude. The predicted asymmetry11 for attractive vs. repulsive scattering of
Dirac fermions is observed. Sigma_min occurs not at the carrier density which
neutralizes nimp, but rather the carrier density at which the average impurity
potential is zero10. Sigma_min decreases initially with nimp, reaching a
minimum near 4e2/h at non-zero nimp, indicating that Sigma_min in present
experimental samples does not probe Dirac-point physics14, 15, 19, 20 but
rather carrier density inhomogeneity due to the impurity potential3, 9, 10.


title:
Ages of Elliptical Galaxies: Single versus Multi Population
  Interpretation

abstract:
  New calibrations of spectrophotometric indices of elliptical galaxies as
functions of spectrophotometric indices are presented, permitting estimates of
mean stellar population ages and metallicities. These calibrations are based on
evolutionary models including a two-phase interstellar medium, infall and a
galactic wind.Free parameters were fixed by requiring that models reproduce the
mean trend of data in the color-magnitude diagram as well as in the plane of
indices Hbeta-Mg2 and Mg2-<Fe>. To improve the location of faint ellipticals(MB
> -20) in the Hbeta-Mg2 diagram, down-sizing was introduced. An application of
our calibrations to a sample of ellipticals and a comparison with results
derived from single stellar population models is given. Our models indicate
that mean population ages span an interval of 7-12 Gyr and are correlated with
metallicities, which range from approximately half up to three times solar.


title: How to become a superhero

abstract:
  We analyze a collaboration network based on the Marvel Universe comic books.
First, we consider the system as a binary network, where two characters are
connected if they appear in the same publication. The analysis of degree
correlations reveals that, in contrast to most real social networks, the Marvel
Universe presents a disassortative mixing on the degree. Then, we use a weight
measure to study the system as a weighted network. This allows us to find and
characterize well defined communities. Through the analysis of the community
structure and the clustering as a function of the degree we show that the
network presents a hierarchical structure. Finally, we comment on possible
mechanisms responsible for the particular motifs observed.


title:
Flow and critical velocity of an imbalanced Fermi gas through an optical
  potential

abstract:
  Optical lattices offer the possibility to investigate the superfluid
properties of both Bose condensates and Fermionic superfluid gases. When a
population imbalance is present in a Fermi mixture, this leads to frustration
of the pairing, and the superfluid properties will be affected. In this
contribution, the influence of imbalance on the flow of a Fermi superfluid
through an optical lattice is investigated. The flow through the lattice is
analysed by taking into account coupling between neighbouring layers of the
optical lattice up to second order in the interlayer tunneling amplitude for
single atoms. The critical velocity of flow through the lattice is shown to
decrease monotonically to zero as the imbalance is increased to 100%.
Closed-form analytical expressions are given for the tunneling contribution to
the action and for the critical velocity as a function of the binding energy of
pairs in the (quasi) two-dimensional Fermi superfluid and as a function of the
imbalance.


title:
Current-Induced Motion of Narrow Domain Walls and Dissipation in
  Ferromagnetic Metals

abstract:
  Spin transport equations in a non-homogeneous ferromagnet are derived in the
limit where the sd exchange coupling between the electrons in the conduction
band and those in the d band is dominant. It is shown that spin diffusion in
ferromagnets assumes a tensor form. The diagonal terms are renormalized with
respect to that in normal metals and enhances the dissipation in the magnetic
system while the off-diagonal terms renormalize the precessional frequency of
the conduction electrons and enhances the non-adiabatic spin torque. To
demonstrate the new physics in our theory, we show that self-consistent
solutions of the spin diffusion equations and the Landau-Lifshitz equations in
the presence of a current lead to a an increase in the terminal velocity of a
domain wall which becomes strongly dependent on its width. We also provide a
simplified equation that predicts damping due to the conduction electrons.


title: Quark Confinement from Color Confinement

abstract:
  We relate quark confinement, as measured by the Polyakov-loop order
parameter, to color confinement, as described by the
Kugo-Ojima/Gribov-Zwanziger scenario. We identify a simple criterion for quark
confinement based on the IR behaviour of ghost and gluon propagators, and
compute the order-parameter potential from the knowledge of Landau-gauge
correlation functions with the aid of the functional RG. Our approach predicts
the deconfinement transition in quenched QCD to be of first order for SU(3) and
second order for SU(2) -- in agreement with general expectations. As an
estimate for the critical temperature, we obtain T_c=284MeV for SU(3).


title: User Participation in Social Media: Digg Study

abstract:
  The social news aggregator Digg allows users to submit and moderate stories
by voting on (digging) them. As is true of most social sites, user
participation on Digg is non-uniformly distributed, with few users contributing
a disproportionate fraction of content. We studied user participation on Digg,
to see whether it is motivated by competition, fueled by user ranking, or
social factors, such as community acceptance.
  For our study we collected activity data of the top users weekly over the
course of a year. We computed the number of stories users submitted, dugg or
commented on weekly. We report a spike in user activity in September 2006,
followed by a gradual decline, which seems unaffected by the elimination of
user ranking. The spike can be explained by a controversy that broke out at the
beginning of September 2006. We believe that the lasting acrimony that this
incident has created led to a decline of top user participation on Digg.


title: Aging Effects Across the Metal-Insulator Transition in Two Dimensions

abstract:
  Aging effects in the relaxations of conductivity of a two-dimensional
electron system in Si have been studied as a function of carrier density. They
reveal an abrupt change in the nature of the glassy phase at the
metal-insulator transition (MIT): (a) while full aging is observed in the
insulating regime, there are significant departures from full aging on the
metallic side of the MIT, before the glassy phase disappears completely at a
higher density $n_g$; (b) the amplitude of the relaxations peaks just below the
MIT, and it is strongly suppressed in the insulating phase. Other aspects of
aging, including large non-Gaussian noise and similarities to spin glasses,
also have been discussed.


title:
Centrality dependence of charged hadron production in deuteron+gold and
  nucleon+gold collisions at sqrt(s_NN)=200 GeV

abstract:
  We present transverse momentum (p_T) spectra of charged hadrons measured in
deuteron-gold and nucleon-gold collisions at \sqrts = 200 GeV for four
centrality classes. Nucleon-gold collisions were selected by tagging events in
which a spectator nucleon was observed in one of two forward rapidity
detectors. The spectra and yields were investigated as a function of the number
of binary nucleon-nucleon collisions, \nu, suffered by deuteron nucleons. A
comparison of charged particle yields to those in p+p collisions show that the
yield per nucleon-nucleon collision saturates with \nu for high momentum
particles. We also present the charged hadron to neutral pion ratios as a
function of p_T.


title: Induced-charge Electrophoresis of Metallo-dielectric Particles

abstract:
  The application of AC electric fields in aqueous suspensions of anisotropic
particles leads to unbalanced liquid flows and nonlinear, induced-charge
electrophoretic (ICEP) motion. We report experimental observations of the
motion of "Janus" microparticles with one dielectric and one metal-coated
hemisphere induced by uniform fields of frequency 100 Hz - 10 kHz in NaCl
solutions. The motion is perpendicular to the field axis and persists after
particles are attracted to a glass wall. This phenomenon may find applications
in microactuators, microsensors, and microfluidic devices.


title: Local aging phenomena close to magnetic surfaces

abstract:
  Surface aging phenomena are discussed for semi-infinite systems prepared in a
fully disordered initial state and then quenched to or below the critical
point. Besides solving exactly the semi-infinite Ising model in the limit of
large dimensions, we also present results of an extensive numerical study of
the nonequilibrium dynamical behavior of the two-dimensional semi-infinite
Ising model undergoing coarsening. The studied models reveal a simple aging
behavior where some of the nonequilibrium surface exponents take on values that
differ from their bulk counterparts. For the two-dimensional semi-infinite
Ising model we find that the exponent $b_1$, that describes the scaling
behavior of the surface autocorrelation, vanishes. These simulations also
reveal the existence of strong finite-time corrections that to some extent mask
the leading scaling behavior of the studied two-time quantities.


title:
A Path Integral Method for Coarse-Graining Noise in Stochastic
  Differential Equations with Multiple Time Scales

abstract:
  We present a new path integral method to analyze stochastically perturbed
ordinary differential equations with multiple time scales. The objective of
this method is to derive from the original system a new stochastic differential
equation describing the system's evolution on slow time scales. For this
purpose, we start from the corresponding path integral representation of the
stochastic system and apply a multi-scale expansion to the associated path
integral kernel of the corresponding Lagrangian. As a concrete example, we
apply this expansion to a system that arises in the study of random dispersion
fluctuations in dispersion-managed fiber optic communications. Moreover, we
show that, for this particular example, the new path integration method yields
the same result at leading order as an asymptotic expansion of the associated
Fokker-Planck equation.


title:
New Radio Sources and the Composite Structure of Component B in the Very
  Young Protostellar System IRAS 16293-2422

abstract:
  In this article, we report high-resolution (~ 0.1" -- 0.3"), high-sensitivity
(~ 50 -100 uJy beam-1) Very Large Array 0.7 and 1.3 cm observations of the
young stellar system IRAS 16293-2422 in rho-Ophiuchus. In the 0.7 cm image,
component A to the south-east of the system looks like its usual binary self.
In the new 1.3 cm image, however, component A2 appears to have split into two
sub-components located roughly symmetrically around the original position of
A2. This change of morphology is likely the result of a recent bipolar
ejection, one of the very first such events observed in a low-mass source. Also
in component A, a marginal detection of 0.7 cm emission associated with the
submillimeter component Ab is reported. If confirmed, this detection would
imply that Ab is a relatively extended dusty structure, where grain coagulation
may already have taken place. With an angular size increasing with frequency,
and an overall spectra index of 2, the emission from component B to the
north-west of the system is confirmed to be dominated by optically thick
thermal dust emission associated with a fairly massive, nearly face-on,
circumstellar disk. In the central region, however, we find evidence for a
modest free-free contribution that originates in a structure elongated roughly
in the east-west direction. We argue that this free-free component traces the
base of the jet driving the large-scale bipolar flow at a position angle of
about 110 degrees that has long been known to be powered by IRAS 16293-2422.


title:
Propagation of large concentration changes in reversible protein binding
  networks

abstract:
  We study how the dynamic equilibrium of the reversible protein-protein
binding network in yeast Saccharomyces cerevisiae responds to large changes in
abundances of individual proteins. The magnitude of shifts between free and
bound concentrations of their immediate and more distant neighbors in the
network is influenced by such factors as the network topology, the distribution
of protein concentrations among its nodes, and the average binding strength.
Our primary conclusion is that, on average, the effects of a perturbation are
strongly localized and exponentially decay with the network distance away from
the perturbed node, which explains why, despite globally connected topology,
individual functional modules in such networks are able to operate fairly
independently. We also found that under specific favorable conditions, realized
in a significant number of paths in the yeast network, concentration
perturbations can selectively propagate over considerable network distances (up
to four steps). Such "action-at-a-distance" requires high concentrations of
heterodimers along the path as well as low free (unbound) concentration of
intermediate proteins.


title:
Direct Microlensing-Reverberation Observations of the Intrinsic magnetic
  Structure of AGN in Different Spectral States: A Tale of Two Quasars

abstract:
  We show how direct microlensing-reverberation analysis performed on two
well-known Quasars (Q2237 - The Einstein Cross and Q0957 - The Twin) can be
used to observe the inner structure of two quasars which are in significantly
different spectral states. These observations allow us to measure the detailed
internal structure of quasar Q2237 in a radio quiet high-soft state, and
compare it to quasar Q0957 in a radio loud low-hard state. We find that the
observed differences in the spectral states of these two quasars can be
understood as being due to the location of the inner radii of their accretion
disks relative to the co-rotation radii of rotating intrinsically magnetic
supermassive compact objects in the centers of these quasars.


title: Zero minors of the neutrino mass matrix

abstract:
  We examine the possibility that a certain class of neutrino mass matrices,
namely those with two independent vanishing minors in the flavor basis,
regardless of being invertible or not, is sufficient to describe current data.
We compute generic formulae for the ratios of the neutrino masses and for the
Majorana phases. We find that seven textures with two vanishing minors can
accommodate the experimental data. We present an estimate of the mass matrix
for these patterns. All the possible textures can be dynamically generated
through the seesaw mechanism augmented with a discrete Abelian symmetry.