title: Distribution and asymptotics under beta random scaling

abstract:
  Let X,Y,B be three independent random variables such that $X$ has the same
distribution function as Y B. Assume that B is a Beta random variable with
positive parameters a,b and Y has distribution function H. Pakes and Navarro
(2007) show under some mild conditions that the distribution function H_{a,b}
of X determines H. Based on that result we derive in this paper a recursive
formula for calculation of H, if H_{a,b} is known. Furthermore, we investigate
the relation between the tail asymptotic behaviour of X and Y. We present three
applications of our asymptotic results concerning the extremes of two random
samples with underlying distribution functions H and H_{a,b}, respectively, and
the conditional limiting distribution of bivariate elliptical distributions.


title:
Elagage d'un perceptron multicouches : utilisation de l'analyse de la
  variance de la sensibilit\'e des param\`etres

abstract:
  The stucture determination of a neural network for the modelisation of a
system remain the core of the problem. Within this framework, we propose a
pruning algorithm of the network based on the use of the analysis of the
sensitivity of the variance of all the parameters of the network. This
algorithm will be tested on two examples of simulation and its performances
will be compared with three other algorithms of pruning of the literature


title:
Quantum Monte Carlo method applied to strongly correlated dilute fermi
  gases with finite effective range

abstract:
  We discuss the Auxiliary Field Quantum Monte Carlo (AFQMC) method applied to
dilute neutron matter at finite temperatures. We formulate the discrete
Hubbard-Stratonovich transformation for the interaction with finite effective
range which is free from the sign problem. The AFQMC results are compared with
those obtained from exact diagonalization for a toy model. Preliminary
calculations of energy and chemical potential as a function of temperature are
presented.


title:
No metastable de Sitter vacua in N=2 supergravity with only
  hypermultiplets

abstract:
  We study the stability of vacua with spontaneously broken supersymmetry in
N=2 supergravity theories with only hypermultiplets. Focusing on the projection
of the scalar mass matrix along the sGoldstino directions, we are able to
derive a universal upper bound on the lowest mass eigenvalue. This bound only
depends on the gravitino mass and the cosmological constant, but not on the
details of the quaternionic manifold spanned by the scalar fields. Comparing
with the Breitenlohner-Freedman bound shows that metastability requires the
cosmological constant to be smaller than a certain negative critical value.
Therefore, only AdS vacua with a sufficiently negative cosmological constant
can be stable, while Minkowski and dS vacua necessarily have a tachyonic
direction.


title: Elementary epistemological features of machine intelligence

abstract:
  Theoretical analysis of machine intelligence (MI) is useful for defining a
common platform in both theoretical and applied artificial intelligence (AI).
The goal of this paper is to set canonical definitions that can assist
pragmatic research in both strong and weak AI. Described epistemological
features of machine intelligence include relationship between intelligent
behavior, intelligent and unintelligent machine characteristics, observable and
unobservable entities and classification of intelligence. The paper also
establishes algebraic definitions of efficiency and accuracy of MI tests as
their quality measure. The last part of the paper addresses the learning
process with respect to the traditional epistemology and the epistemology of MI
described here. The proposed views on MI positively correlate to the Hegelian
monistic epistemology and contribute towards amalgamating idealistic
deliberations with the AI theory, particularly in a local frame of reference.


title: An operator extension of Bohr's inequality

abstract:
  We establish an operator extension of the following generalization of Bohr's
inequality, due to M.P. Vasi\'c and D.J. Ke\v{c}ki\'{c}: $$|\sum_{i=1}^n z_i|^r
\leq (\sum_{i=1}^n \alpha_i^{1/(1-r)})^{r-1}\sum_{i=1}^n \alpha_i|z_i|^r \quad
(r>1, z_i \in{\mathbb C}, \alpha_i>0, 1 \leq i \leq n) .$$ We also present some
norm inequalities related to our noncommutative generalization of Bohr's
inequality.


title:
Super-ASTROD: Probing primordial gravitational waves and mapping the
  outer solar system

abstract:
  Super-ASTROD (Super Astrodynamical Space Test of Relativity using Optical
Devices or ASTROD III) is a mission concept with 3-5 spacecraft in 5 AU orbits
together with an Earth-Sun L1/L2 spacecraft ranging optically with one another
to probe primordial gravitational-waves with frequencies 0.1 microHz - 1 mHz,
to test fundamental laws of spacetime and to map the outer solar system. In
this paper we address to its scientific goals, orbit and payload selection, and
sensitivity to gravitational waves.


title:
Transverse rotation of the momentary field distribution and the orbital
  angular momentum of a light beam

abstract:
  The transverse beam pattern, usually observed in experiment, is a result of
averaging the optical-frequency oscillations of the electromagnetic field
distributed over the beam cross section. An analytical criterion is derived
that these oscillations are coupled with a sort of rotation around the beam
axis. This criterion appears to be in direct relation with the usual definition
of the beam orbital angular momentum.


title:
A characterization of Hilbert $C^*$-modules over finite dimensional
  $C^*$-algebras

abstract:
  We show that the unit ball of a full Hilbert $C^*$-module is sequentially
compact in a certain weak topology if and only if the underlying $C^*$-algebra
is finite dimensional. This provides an answer to the question posed in J.
Chmieli\'nski et al [Perturbation of the Wigner equation in inner product
$C^*$-modules, J. Math. Phys. 49 (2008), no. 3, 033519; arXiv:0801.2726].


title:
Wakimoto realization of Drinfeld current for the elliptic quantum
  algebra $U_{q,p}(sl_3^)$

abstract:
  We study a free field realization of the elliptic quantum algebra
$U_{q,p}(sl_3^)$ for arbitrary level $k$. We give the free field realization of
elliptic analogue of Drinfeld current associated with $U_{q,p}(sl_3^)$ for
arbitrary level $k$. In the limit $p \to 0, q \to 1$ our realization reproduce
Wakimoto realization for the affine Lie algebra $sl_3^$.


title: Quantum state transfer in a q-deformed chain

abstract:
  We investigate the quantum state transfer in a chain of particles satisfying
q-deformed oscillators algebra. This general algebraic setting includes the
spin chain and the bosonic chain as limiting cases. We study conditions for
perfect state transfer depending on the number of sites and excitations on the
chain. They are formulated by means of irreducible representations of a quantum
algebra realized through Jordan-Schwinger maps. Playing with deformation
parameters, we can study the effects of nonlinear perturbations or interpolate
between the spin and bosonic chain.


title:
Renormalization of Supersymmetric Field Theories in Loop Regularization
  with String-mode Regulators

abstract:
  By applying the recently developed Loop Regularization(LR) with string-mode
regulators to supersymmetric field theories, we explicitly verify the
supersymmetric Ward identities in several supersymmetric models at one-loop
level. It is interesting to observe that supersymmetry is a so remarkable
symmetry that the supersymmetric Ward identities hold as long as a
regularization scheme is realized in the exact four dimensional space-time with
translational invariance for the momentum integration, and the gauge symmetry
can be maintained once the regularization scheme preserves supersymmetry and
satisfies the consistency condition for logarithmic divergences. As a manifest
demonstration, we carry out a complete one-loop renormalization for the massive
Wess-Zumino model by adopting the LR method, it is found that all the quadratic
divergences cancel out and the relations among masses and coupling constants
hold after renormalization, which agrees with the well-known
non-renormalization theorem. It is concluded that the LR method preserves not
only gauge symmetry but also supersymmetry. A simple and definite derivation of
Majorana Feynman rules is found to be very useful.


title:
Linear-Time Algorithms for Geometric Graphs with Sublinearly Many Edge
  Crossings

abstract:
  We provide linear-time algorithms for geometric graphs with sublinearly many
crossings. That is, we provide algorithms running in O(n) time on connected
geometric graphs having n vertices and k crossings, where k is smaller than n
by an iterated logarithmic factor. Specific problems we study include Voronoi
diagrams and single-source shortest paths. Our algorithms all run in linear
time in the standard comparison-based computational model; hence, we make no
assumptions about the distribution or bit complexities of edge weights, nor do
we utilize unusual bit-level operations on memory words. Instead, our
algorithms are based on a planarization method that "zeroes in" on edge
crossings, together with methods for extending planar separator decompositions
to geometric graphs with sublinearly many crossings. Incidentally, our
planarization algorithm also solves an open computational geometry problem of
Chazelle for triangulating a self-intersecting polygonal chain having n
segments and k crossings in linear time, for the case when k is sublinear in n
by an iterated logarithmic factor.


title: Boxicity and Cubicity of Asteroidal Triple free graphs

abstract:
  An axis parallel $d$-dimensional box is the Cartesian product $R_1 \times R_2
\times ... \times R_d$ where each $R_i$ is a closed interval on the real line.
The {\it boxicity} of a graph $G$, denoted as $\boxi(G)$, is the minimum
integer $d$ such that $G$ can be represented as the intersection graph of a
collection of $d$-dimensional boxes. An axis parallel unit cube in
$d$-dimensional space or a $d$-cube is defined as the Cartesian product $R_1
\times R_2 \times ... \times R_d$ where each $R_i$ is a closed interval on the
real line of the form $[a_i,a_i + 1]$. The {\it cubicity} of $G$, denoted as
$\cub(G)$, is the minimum integer $d$ such that $G$ can be represented as the
intersection graph of a collection of $d$-cubes.
  Let $S(m)$ denote a star graph on $m+1$ nodes. We define {\it claw number} of
a graph $G$ as the largest positive integer $k$ such that $S(k)$ is an induced
subgraph of $G$ and denote it as $\claw$.
  Let $G$ be an AT-free graph with chromatic number $\chi(G)$ and claw number
$\claw$. In this paper we will show that $\boxi(G) \leq \chi(G)$ and this bound
is tight. We also show that $\cub(G) \leq \boxi(G)(\ceil{\log_2 \claw} +2)$
$\leq$ $\chi(G)(\ceil{\log_2 \claw} +2)$. If $G$ is an AT-free graph having
girth at least 5 then $\boxi(G) \leq 2$ and therefore $\cub(G) \leq
2\ceil{\log_2 \claw} +4$.


title:
Meixner class of non-commutative generalized stochastic processes with
  freely independent values I. A characterization

abstract:
  Let $T$ be an underlying space with a non-atomic measure $\sigma$ on it (e.g.
$T=\mathbb R^d$ and $\sigma$ is the Lebesgue measure). We introduce and study a
class of non-commutative generalized stochastic processes, indexed by points of
$T$, with freely independent values. Such a process (field),
$\omega=\omega(t)$, $t\in T$, is given a rigorous meaning through smearing out
with test functions on $T$, with $\int_T \sigma(dt)f(t)\omega(t)$ being a
(bounded) linear operator in a full Fock space. We define a set $\mathbf{CP}$
of all continuous polynomials of $\omega$, and then define a con-commutative
$L^2$-space $L^2(\tau)$ by taking the closure of $\mathbf{CP}$ in the norm
$\|P\|_{L^2(\tau)}:=\|P\Omega\|$, where $\Omega$ is the vacuum in the Fock
space. Through procedure of orthogonalization of polynomials, we construct a
unitary isomorphism between $L^2(\tau)$ and a (Fock-space-type) Hilbert space
$\mathbb F=\mathbb R\oplus\bigoplus_{n=1}^\infty L^2(T^n,\gamma_n)$, with
explicitly given measures $\gamma_n$. We identify the Meixner class as those
processes for which the procedure of orthogonalization leaves the set $\mathbf
{CP}$ invariant. (Note that, in the general case, the projection of a
continuous monomial of oder $n$ onto the $n$-th chaos need not remain a
continuous polynomial.) Each element of the Meixner class is characterized by
two continuous functions $\lambda$ and $\eta\ge0$ on $T$, such that, in the
$\mathbb F$ space, $\omega$ has representation
$\omega(t)=\di_t^\dag+\lambda(t)\di_t^\dag\di_t+\di_t+\eta(t)\di_t^\dag\di^2_t$,
where $\di_t^\dag$ and $\di_t$ are the usual creation and annihilation
operators at point $t$.


title:
Lowering and raising operators for the free Meixner class of orthogonal
  polynomials

abstract:
  We compare some properties of the lowering and raising operators for the
classical and free classes of Meixner polynomials on the real line.


title:
A model for retention on short, intermediate and long time-scale in
  ferroelectric thin films

abstract:
  We developed a model with no adjustable parameter for retention loss at short
and long time scale in ferroelectric thin-film capacitors. We found that the
predictions of this model are in good agreement with the experimental
observations in the literature. In particular, it explains why a power-law
function shows better fitting than a linear-log relation on a short time scale
(10^-7 s to 1 s) and why a stretched exponential relation gives more precise
description than a linear-log plot on a long time scale (>100 s), as reported
by many researchers in the past. More severe retention losses at higher
temperatures and in thinner films have also been correctly predicted by the
present theory.


title: Murphy elements from the double-row transfer matrix

abstract:
  We consider the double-row (open) transfer matrix constructed from generic
tensor-type representations of various types of Hecke algebras. For different
choices of boundary conditions for the relevant integrable lattice model we
express the double-row transfer matrix solely in terms of generators of the
corresponding Hecke algebra (tensor-type realizations). We then expand the open
transfer matrix and extract the associated Murphy elements from the first/last
terms of the expansion. Suitable combinations of the Murphy elements as has
been shown commute with the corresponding Hecke algebra.


title: Ergodic properties of linked-twist maps

abstract:
  We study a class of homeomorphisms of surfaces collectively known as
linked-twist maps. We introduce an abstract definition which enables us to give
a precise characterisation of a property observed by other authors, namely that
such maps fall into one of two classes termed co- and counter-twisting. We
single out three specific linked-twist maps, one each on the two-torus, in the
plane and on the two-sphere and for each prove a theorem concerning its ergodic
properties with respect to the invariant Lebesgue measure.
  For the map on the torus we prove that there is an invariant, zero-measure
Cantor set on which the dynamics are topologically conjugate to a full shift on
the space of symbol sequences. Such features are commonly known as topological
horseshoes. For the map in the plane we prove that there is a set of full
measure on which the dynamics are measure-theoretically isomorphic to a full
shift on the space of symbol sequences. This is commonly known as the Bernoulli
property and verifies, under certain conditions, a conjecture of Wojtkowski's.
We introduce the map on the sphere and prove that it too has the Bernoulli
property.
  We conclude with some conjectures, drawn from our experience, concerning how
one might extend the results we have for specific linked-twist maps to the
abstract linked-twist maps we have defined.


title: Multi-fermion interaction models in curved spacetime

abstract:
  A model with a scalar type eight-fermion interaction is investigated in
curved spacetime. The ground state of the model can be obtained by observing
the effective potential. Applying the Riemann normal coordinate expansion, we
calculate an effective potential of the model in a weakly curved spacetime. The
result is extended to models with multi-fermion interactions. We numerically
show the behavior of the effective potential and find the phase structure of
the model.


title:
Two-Dimensional particle-in-cell simulations of the nonresonant,
  cosmic-ray driven instability in SNR shocks

abstract:
  In supernova remnants, the nonlinear amplification of magnetic fields
upstream of collisionless shocks is essential for the acceleration of cosmic
rays to the energy of the "knee" at 10^{15.5}eV. A nonresonant instability
driven by the cosmic ray current is thought to be responsible for this effect.
We perform two-dimensional, particle-in-cell simulations of this instability.
We observe an initial growth of circularly polarized non-propagating magnetic
waves as predicted in linear theory. It is demonstrated that in some cases the
magnetic energy density in the growing waves, can grow to at least 10 times its
initial value. We find no evidence of competing modes, nor of significant
modification by thermal effects. At late times we observe saturation of the
instability in the simulation, but the mechanism responsible is an artefact of
the periodic boundary conditions and has no counterpart in the supernova-shock
scenario.


title:
Gantmakher-Krein theorem for 2-totally nonnegative operators in ideal
  spaces

abstract:
  The tensor and exterior squares of a completely continuous non-negative
linear operator $A$ acting in the ideal space $X(\Omega)$ are studied. The
theorem representing the point spectrum (except, probably, zero) of the tensor
square $A \otimes A$ in the terms of the spectrum of the initial operator $A$
is proved. The existence of the second (according to the module) positive
eigenvalue $\lambda_2$, or a pair of complex adjoint eigenvalues of a
completely continuous non-negative operator $A$ is proved under the additional
condition, that its exterior square $A\wedge A$ is also nonnegative.


title: AGB Stars in the Fornax Dwarf Spheroidal Galaxy

abstract:
  We report on a multi-epoch study of the Fornax dwarf spheroidal galaxy, made
with the Infrared Survey Facility, over an area of about 42'x42'. The
colour-magnitude diagram shows a broad well-populated giant branch with a tip
that slopes down-wards from red to blue, as might be expected given Fornax's
known range of age and metallicity. The extensive AGB includes seven Mira
variables and ten periodic semi-regular variables. Five of the seven Miras are
known to be carbon rich. Their pulsation periods range from 215 to 470 days,
indicating a range of initial masses. Three of the Fornax Miras are redder than
typical LMC Miras of similar period, probably indicating particularly heavy
mass-loss rates. Many, but not all, of the characteristics of the AGB are
reproduced by isochrones from Marigo et al. for a 2 Gyr population with a
metallicity of Z=0.0025.
  An application of the Mira period-luminosity relation to these stars yields a
distance modulus for Fornax of 20.69+/-0.04 (internal), +/-0.08 (total) (on a
scale that puts the LMC at 18.39 mag) in good agreement with other
determinations. Various estimates of the distance to Fornax are reviewed.


title:
An Approximation of the Outage Probability for Multi-hop AF Fixed Gain
  Relay

abstract:
  In this letter, we present a closed-form approximation of the outage
probability for the multi-hop amplify-and-forward (AF) relaying systems with
fixed gain in Rayleigh fading channel. The approximation is derived from the
outage event for each hop. The simulation results show the tightness of the
proposed approximation in low and high signal-to-noise ratio (SNR) region.


title: Distances to Galactic methanol masers

abstract:
  We present the first EVN parallax measurements of 6.7 GHz methanol masers in
star forming regions of the Galaxy. The 6.7 GHz methanol maser transition is a
very valuable astrometric tool, for its large stability and confined velocity
spread, which makes it ideal to measure proper motions and parallaxes. Eight
well-studied massive star forming regions have been observed during five EVN
sessions of 24 hours duration each and we present here preliminary results for
five of them. We achieve accuracies of up to 51 $\mu$as, which still have the
potential to be proved by more ideal observational circumstances.


title: An Entropy Inequality

abstract:
  Let $S(\rho)=- Tr (\rho \log\rho)$ be the von Neumann entropy of an
$N$-dimensional quantum state $\rho$ and
  $e_2(\rho)$ the second elementary symmetric polynomial of the eigenvalues of
$\rho$. We prove the inequality $S(\rho) \le c(N) \sqrt{e_2(\rho)} $ where
$c(N)=\log(N) \sqrt{\frac{2N}{N-1}}$. This generalizes an inequality given by
Fuchs and Graaf \cite{fuchsgraaf} for the case of one qubit, i.e., N=2.
Equality is achieved if and only if $\rho$ is either a pure or the maximally
mixed state. This inequality delivers new bounds for quantities of interest in
quantum information theory, such as upper bounds for the minimum output entropy
and the entanglement of formation as well as a lower bound for the Holevo
channel capacity.


title:
One-dimensional Ising ferromagnet frustrated by long-range interactions
  at finite temperatures

abstract:
  We consider a one-dimensional lattice of Ising-type variables where the
ferromagnetic exchange interaction J between neighboring sites is frustrated by
a long-ranged anti-ferromagnetic interaction of strength g between the sites i
and j, decaying as |i-j|^-alpha, with alpha>1. For alpha smaller than a certain
threshold alpha_0, which is larger than 2 and depends on the ratio J/g, the
ground state consists of an ordered sequence of segments with equal length and
alternating magnetization. The width of the segments depends on both alpha and
the ratio J/g. Our Monte Carlo study shows that the on-site magnetization
vanishes at finite temperatures and finds no indication of any phase
transition. Yet, the modulation present in the ground state is recovered at
finite temperatures in the two-point correlation function, which oscillates in
space with a characteristic spatial period: The latter depends on alpha and J/g
and decreases smoothly from the ground-state value as the temperature is
increased. Such an oscillation of the correlation function is exponentially
damped over a characteristic spatial scale, the correlation length, which
asymptotically diverges roughly as the inverse of the temperature as T=0 is
approached. This suggests that the long-range interaction causes the Ising
chain to fall into a universality class consistent with an underlying
continuous symmetry. The e^(Delta/T)-temperature dependence of the correlation
length and the uniform ferromagnetic ground state, characteristic of the g=0
discrete Ising symmetry, are recovered for alpha > alpha_0.


title:
Lane formation in driven colloidal mixtures: is it continuous or
  discontinuous?

abstract:
  Binary mixtures of oppositely charged colloids driven by an electric field
are shown to exhibit a nonequilibrium transition towards lane formation if the
driving force is increased. Brownian dynamics computer simulations and
real-space experiments are employed to study hysteresis effects in an order
parameter measuring the extent of lane formation upon increasing and decreasing
the driving force. Both from simulation and experiment, we find that lane
formation due to electrical fields is continuous. However, simulations show a
discontinuous transition if the driving force is gravity.


title:
Catching blazars in the act! GLAST triggers for TeV observation of
  blazars

abstract:
  The double humped SED (Spectral Energy Distribution) of blazars, and their
flaring phenomena can be explained by various leptonic and hadronic models.
However, accurate modeling of the high frequency component and clear
identification of the correct emission mechanism would require simultaneous
measurements in both the MeV-GeV band and the TeV band. Due to the differences
in the sensitivity and the field of view of the instruments required to do
these measurements, it is essential to identify active states of blazars likely
to be detected with TeV instruments.
  Using a reasonable intergalactic attenuation model, various extrapolations of
the EGRET spectra, as a proxy for GLAST (Gamma-ray Large Area Space Telescope)
measurements, are made into TeV energies for selecting EGRET blazars expected
to be VHE-bright. Furthermore, estimates of the threshold fluxes at GLAST
energies are provided, at which sources are expected to be detectable at TeV
energies, with Cherenkov telescopes like HESS, MAGIC or VERITAS.


title:
Model building by coset space dimensional reduction in ten-dimensions
  with direct product gauge symmetry

abstract:
  We investigate ten-dimensional gauge theories whose extra six-dimensional
space is a compact coset space, $S/R$, and gauge group is a direct product of
two Lie groups. We list up candidates of the gauge group and embeddings of $R$
into them. After dimensional reduction of the coset space,we find fermion and
scalar representations of $G_{\mathrm{GUT}} \times U(1)$ with
$G_{\mathrm{GUT}}=SU(5), SO(10)$ and $E_6$ which accomodate all of the standard
model particles. We also discuss possibilities to generate distinct Yukawa
couplings among the generations using representations with a different
dimension for $G_{\mathrm{GUT}}=SO(10)$ and $E_6$ models.


title: White dwarfs in the Capodimonte deep field

abstract:
  In this article we describe the search for white dwarfs (WDs) in the
multi-band photometric data of the Capodimonte deep field survey. The WD
candidates were selected through the V-R_C vs B-V color-color diagram. For two
bright objects, the WD nature has been confirmed spectroscopically, and the
atmospheric parameters (Teff and logg) have been determined. We have computed
synthetic stellar population models for the observed field and the expected
number of white dwarfs agrees with the observations. The possible contamination
by turn-off and horizontal branch halo stars has been estimated. The quasar
(QSO) contamination has been determined by comparing the number of WD
candidates in different color bins with state-of-the-art models and previous
observations. The WD space density is measured at different distances from the
Sun. The total contamination (non-degenerate stars + QSOs) in our sample is
estimated to be around 30%. This work should be considered a small experiment
in view of more ambitious projects to be performed in the coming years in
larger survey contexts.


title: Achieving control of in-plane elastic waves

abstract:
  We derive the elastic properties of a cylindrical cloak for in-plane coupled
shear and pressure waves. The cloak is characterized by a rank 4 elasticity
tensor with 16 spatially varying entries which are deduced from a geometric
transform. Remarkably, the Navier equations retain their form under this
transform, which is generally untrue [Milton et al., New J. Phys. 8, 248
(2006)]. We numerically check that clamped and freely vibrating obstacles
located inside the neutral region are cloaked disrespectful of the frequency
and the polarization of an incoming elastic wave.


title: The Mirage of Triangular Arbitrage in the Spot Foreign Exchange Market

abstract:
  We investigate triangular arbitrage within the spot foreign exchange market
using high-frequency executable prices. We show that triangular arbitrage
opportunities do exist, but that most have short durations and small
magnitudes. We find intra-day variations in the number and length of arbitrage
opportunities, with larger numbers of opportunities with shorter mean durations
occurring during more liquid hours. We demonstrate further that the number of
arbitrage opportunities has decreased in recent years, implying a corresponding
increase in pricing efficiency. Using trading simulations, we show that a
trader would need to beat other market participants to an unfeasibly large
proportion of arbitrage prices to profit from triangular arbitrage over a
prolonged period of time. Our results suggest that the foreign exchange market
is internally self-consistent and provide a limited verification of market
efficiency.


title:
Laser-induced disassembly of a graphene single crystal into a
  nano-crystalline network

abstract:
  We report about investigations of time-dependent structural modifications in
single crystal graphene due to laser irradiation even at moderate power levels
of 1mW in a diffraction limited spot. The structural modifications have been
characterized by in situ scanning confocal Raman spectroscopy, atomic force
height microscopy and transport studies. The time evolution of the Raman
spectrum reveals two different effects: on a short time scale, dopants,
initially present on the flake, are removed. The longer time scale behavior
points to a laser induced gradual local decomposition of single crystal
graphene into a network of interconnected nano-crystallites with a
characteristic length scale of approximately 10 nm due to bond-breaking. The
broken bonds offer additional docking sites for adsorbates as confirmed in
transport and AFM height studies. These controlled structural modifications may
for instance be valuable for enhancing the local reactivity and trimming
graphene based gas sensors.


title: Multiple phase slips phenomena in mesoscopic superconducting rings

abstract:
  We investigate the behavior of a mesoscopic one-dimensional ring in an
external magnetic field by simulating the time dependent Ginzburg-Landau
equations with periodic boundary conditions. We analyze the stability and the
different possible evolutions for the phase slip phenomena starting from a
metastable state. We find a stability condition relating the winding number of
the initial solution and the number of flux quanta penetrating the ring. The
analysis of multiple phase slips solutions is based on analytical results and
simulations. The role of the ratio of two characteristic times u is studied for
the case of a multiple phase slips transition. We found out that if u>>1,
consecutive multiple phase slips will be more favorable than simultaneous ones.
If u<<1 the opposite is true and we confirm that u>>1 is often a necessary
condition to reach the ground state. The influence of the Langevin noise on the
kinetics of the phase transition is discussed.


title:
Scaling of Clusters and Winding Angle Statistics of Iso-height Lines in
  two-dimensional KPZ Surface

abstract:
  We investigate the statistics of Iso-height lines of (2+1)-dimensional
Kardar-Parisi-Zhang model at different level sets around the mean height in the
saturation regime. We find that the exponent describing the distribution of the
height-cluster size behaves differently for level cuts above and below the mean
height, while the fractal dimensions of the height-clusters and their
perimeters remain unchanged. The winding angle statistics also confirms again
the conformal invariance of these contour lines in the same universality class
of self-avoiding random walks (SAWs).


title:
An excess of emission in the dark cloud LDN 1111 with the Arcminute
  Microkelvin Imager

abstract:
  We present observations of the Lynds' dark nebula LDN 1111 made at microwave
frequencies between 14.6 and 17.2 GHz with the Arcminute Microkelvin Imager
(AMI). We find emission in this frequency band in excess of a thermal
free--free spectrum extrapolated from data at 1.4 GHz with matched uv-coverage.
This excess is > 15 sigma above the predicted emission. We fit the measured
spectrum using the spinning dust model of Drain & Lazarian (1998a) and find the
best fitting model parameters agree well with those derived from Scuba data for
this object by Visser et al. (2001).


title: On the range of 3D dislocation pair correlations

abstract:
  Numerical studies of dislocation pair correlations have played a central role
in deriving a continuum theory from the equations of motion of 2D dislocation
systems in a mathematically rigorous way. As part of an effort to extend this
theory into the full 3D dislocation problem, 3D dislocation pair correlations
were studied with discrete dislocation dynamics simulation. As a first
approximation, dislocations were modeled as uncharged curves in space (their
Burgers vectors were disregarded). An inverse square decay with distance was
found to describe the numerically obtained pair correlations of the studied
curve system.


title: Top-quark pair production near threshold at LHC

abstract:
  The next-to-leading order analysis for the cross section for hadroproduction
of top quark pairs close to threshold is presented. Within the framework of
non-relativistic QCD a significant enhancement compared to fixed order
perturbation theory is observed which originates from the characteristic
remnant of the 1S peak below production threshold of top quark pairs. The
analysis includes all color singlet and color octet configurations of top quark
pairs in S-wave states and, for the dominant configurations, it employs
all-order soft gluon resummation for the hard parton cross section. Numerical
results for the Large Hadron Collider at $\sqrt{s} = 14 $TeV and $\sqrt{s} = 10
$TeV and also for the Tevatron are presented. The possibility of a top quark
mass measurement from the invariant mass distribution of top quark pairs is
discussed.


title:
Scaling of the diffusion coefficient on the normal form remainder in
  doubly resonant domains

abstract:
  An outline of theoretical estimates is given regarding the dependence of the
value of the diffusion coefficient $D$ on the size $R$ of the remainder of the
normal form in doubly or simply resonant domains of the action space of 3dof
Hamiltonian systems.


title:
Effective equations of motion for constrained quantum systems: A study
  of the Bianchi I loop quantum cosmology

abstract:
  A new mathematical framework is formulated to derive the effective equations
of motion for the constrained quantum system which possesses an internal clock.
In the realm close to classical behavior, the quantum evolution is approximated
by a finite system of coupled but ordinary differential equations adhered to
the weakly imposed Hamiltonian constraint. For the simplified version of loop
quantum cosmology in the Bianchi I model with a free massless scalar filed, the
resulting effective equations of motion affirm the bouncing scenario predicted
by the previous studies: The big bang singularity is resolved and replaced by
the big bounces, which take place up to three times, once in each diagonal
direction, whenever the directional density approaches the critical value in
the regime of Planckian density. It is also revealed that back-reaction arises
from the quantum corrections and modifies the precise value of the directional
density at the bouncing epoch. Additionally, as an example of symmetry
reduction, we study isotropy emerging from the anisotropic Bianchi I model in
the context of effective equations of motion.


title:
PDE-Foam - a probability-density estimation method using self-adapting
  phase-space binning

abstract:
  Probability Density Estimation (PDE) is a multivariate discrimination
technique based on sampling signal and background densities defined by event
samples from data or Monte-Carlo (MC) simulations in a multi-dimensional phase
space. In this paper, we present a modification of the PDE method that uses a
self-adapting binning method to divide the multi-dimensional phase space in a
finite number of hyper-rectangles (cells). The binning algorithm adjusts the
size and position of a predefined number of cells inside the multi-dimensional
phase space, minimising the variance of the signal and background densities
inside the cells. The implementation of the binning algorithm PDE-Foam is based
on the MC event-generation package Foam. We present performance results for
representative examples (toy models) and discuss the dependence of the obtained
results on the choice of parameters. The new PDE-Foam shows improved
classification capability for small training samples and reduced classification
time compared to the original PDE method based on range searching.


title: Bayesian estimation of one-parameter qubit gates

abstract:
  We address estimation of one-parameter unitary gates for qubit systems and
seek for optimal probes and measurements. Single- and two-qubit probes are
analyzed in details focusing on precision and stability of the estimation
procedure. Bayesian inference is employed and compared with the ultimate
quantum limits to precision, taking into account the biased nature of Bayes
estimator in the non asymptotic regime. Besides, through the evaluation of the
asymptotic a posteriori distribution for the gate parameter and the comparison
with the results of Monte Carlo simulated experiments, we show that asymptotic
optimality of Bayes estimator is actually achieved after a limited number of
runs. The robustness of the estimation procedure against fluctuations of the
measurement settings is investigated and the use of entanglement to improve the
overall stability of the estimation scheme is also analyzed in some details.


title:
Theoretische Modellierung granularer Stroeme in duennen Roehren mit
  Langevin-Gleichungen

abstract:
  This is the final version of the author's diploma thesis written at the
Humboldt University of Berlin in 1995. The topic is the flow of granular
material in narrow vertical pipes, driven by the gravity, that is described by
Langevin equations. Neglecting the interactions, we can solve the resulting
Fokker-Planck equation for the homogeneous case. The consideration of inelastic
collisions leads to a Boltzmann equation. Assuming local equilibrium, the
hydrodynamic equations lead to the extension of the Langevin equation formalism
for the inhomogeneous case. For certain parameter ranges, our formalism can
also be used to describe traffic flows. We applied stability analyses to the
hydrodynamic equations and found critical densities for the occurrence of
particle clustering. We used numerical simulations of the Langevin equations to
verify our homogeneous solution as well as the critical densities.


title: ILC Beam Energy Measurement by means of Laser Compton Backscattering

abstract:
  A novel, non-invasive method of measuring the beam energy at the
International Linear Collider is proposed. Laser light collides head-on with
beam particles and either the energy of the Compton scattered electrons near
the kinematic end-point is measured or the positions of the Compton
backscattered $\gamma$-rays, the edge electrons and the unscattered beam
particles are recorded. A compact layout for the Compton spectrometer is
suggested. It consists of a bending magnet and position sensitive detectors
operating in a large radiation environment. Several options for high spatial
resolution detectors are discussed. Simulation studies support the use of an
infrared or green laser and quartz fiber detectors to monitor the backscattered
photons and edge electrons. Employing a cavity monitor, the beam particle
position downstream of the magnet can be recorded with submicrometer precision.
Such a scheme provides a feasible and promising method to access the incident
beam energy with precisions of $10^{-4}$ or better on a bunch-to-bunch basis
while the electron and positron beams are in collision.


title:
A Surprisingly High Pair Fraction for Extremely Massive Galaxies at z ~
  3 in the GOODS NICMOS Survey

abstract:
  We calculate the major pair fraction and derive the major merger fraction and
rate for 82 massive ($M_{*}>10^{11}M_{\odot}$) galaxies at $1.7 < z < 3.0$
utilising deep HST NICMOS data taken in the GOODS North and South fields. For
the first time, our NICMOS data provides imaging with sufficient angular
resolution and depth to collate a sufficiently large sample of massive galaxies
at z $>$ 1.5 to reliably measure their pair fraction history. We find strong
evidence that the pair fraction of massive galaxies evolves with redshift. We
calculate a pair fraction of $f_{m}$ = 0.29 +/- 0.06 for our whole sample at
$1.7 < z < 3.0$. Specifically, we fit a power law function of the form
$f_{m}=f_{0}(1+z)^{m}$ to a combined sample of low redshift data from Conselice
et al. (2007) and recently acquired high redshift data from the GOODS NICMOS
Survey. We find a best fit to the free parameters of $f_{0}$ = 0.008 +/- 0.003
and $m$ = 3.0 +/- 0.4. We go on to fit a theoretically motivated
Press-Schechter curve to this data. This Press-Schechter fit, and the data,
show no sign of levelling off or turning over, implying that the merger
fraction of massive galaxies continues to rise with redshift out to z $\sim$ 3.
Since previous work has established that the merger fraction for lower mass
galaxies turns over at z $\sim$ 1.5 - 2.0, this is evidence that higher mass
galaxies experience more mergers earlier than their lower mass counterparts,
i.e. a galaxy assembly downsizing. Finally, we calculate a merger rate at z =
2.6 of $\Re$ $<$ 5 $\times$ 10$^{5}$ Gpc$^{-3}$ Gyr$^{-1}$, which experiences
no significant change to $\Re$ $<$ 1.2 $\times$ 10$^{5}$ Gpc$^{-3}$ Gyr$^{-1}$
at z = 0.5. This corresponds to an average $M_{*}>10^{11}M_{\odot}$ galaxy
experiencing 1.7 +/- 0.5 mergers between z = 3 and z = 0.


title: On local compactness in quasilinear elliptic problems

abstract:
  One of the major difficulties in nonlinear elliptic problems involving
critical nonlinearities is the compactness of Palais-Smale sequences. In their
celebrated work \cite{BN}, Br\'ezis and Nirenberg introduced the notion of
critical level for these sequences in the case of a critical perturbation of
the Laplacian homogeneous eigenvalue problem. In this paper, we give a natural
and general formula of the critical level for a large class of nonlinear
elliptic critical problems. The sharpness of our formula is established by the
construction of suitable Palais-Smale sequences which are not relatively
compact.


title: Extremal functions for the anisotropic Sobolev inequalities

abstract:
  The existence of multiple nonnegative solutions to the anisotropic critical
problem - \sum_{i=1}^{N} \frac{\partial}{\partial x_i} (| \frac{\partial
u}{\partial x_i} |^{p_i-2} \frac{\partial u}{\partial x_i}) = |u|^{p^*-2} u
{in} \mathbb{R}^N is proved in suitable anisotropic Sobolev spaces. The
solutions correspond to extremal functions of a certain best Sobolev constant.
The main tool in our study is an adaptation of the well-known
concentration-compactness lemma of P.-L. Lions to anisotropic operators.
Futhermore, we show that the set of nontrival solutions $\calS$ is included in
$L^\infty(\R^N)$ and is located outside of a ball of radius $\tau >0$ in
$L^{p^*}(\R^N)$.


title:
Exchange bias and its phase reversal in the zero magnetization admixed
  rare earth intermetallics

abstract:
  Exchange bias effect is an important attribute in several device
applications. Traditionally, it is discussed as a form of exchange anisotropy
at the interface between the ferromagnetic/antiferromagnetic layers of two
distinct systems. We report here on the magnetically ordered alloys possessing
the feature of unidirectional anisotropy, which reverses its sign across a
characteristic temperature. These are admixed rare earth intermetallics,
comprising two dissimilar rare earth (RE) ions, belonging to the two different
halves of the 4f-series and imbibing the notion of ferromagnetic coupling
between the spins of all 4f-rare earth ions and that of the conduction
electrons. Magnetic moments of dissimilar RE ions in such admixed alloys,
however, get antiferromagnetically coupled and they display magnetic
compensation feature such that the field induced reversal in the orientation of
the magnetic moments of dissimilar rare earth ions happens across the
compensation temperature (Tcomp). Above a threshold field, the conduction
electron polarization also reverses its sign across Tcomp, this is argued to
correlate with the observed phase reversal in the exchange bias field.


title:
The Goldbach conjecture resulting from global-local cuspidal
  representations and deformations of Galois representations

abstract:
  In the basic general frame of the Langlands global program, a local p-adic
elliptic semimodule corresponding to a local (left) cuspidal form is
constructed from its global equivalent covered by p-th roots. In the same
context, global and local bilinear deformations of Galois representations
inducing the invariance of their respective residue fields are introduced as
well as global and local bilinear quantum deformations leaving invariant the
orders of the inertia subgroups. More particularly, the inverse quantum
deformation of a closed curve responsible for its splitting directly leads to
the Goldbach conjecture.


title:
Sign reversal in the exchange bias and the collapse of hysteresis width
  across the magnetic compensation temperature in a single crystal of
  Nd0.75Ho0.25Al2

abstract:
  In the admixed Nd0.75Ho0.25Al2 system, magnetic moments of Nd and Ho
occupying the same crystallographic site are antiferromagnetically coupled and
the chosen stoichiometry displays a magnetic compensation behavior (Tcomp of
about 24 K) in all orientations. In the vicinity of Tcomp, the conduction
electron polarization (CEP) assumes the role of a soft ferromagnet exchange
coupled to a pseudo-antiferromagnet comprising Nd/Ho moments, resulting in an
asymmetry in the hysteretic (M-H) loop, i.e., the notion of an exchange bias
field (Hexch). Across Tcomp, the CEP contribution reverses sign, and in
consonance, the asymmetry in the M-H loop also undergoes a phase reversal.
Interestingly, the width of the M-H loop shows a divergence, followed by a
collapse on approaching Tcomp from either end. The observed behavior confirms a
long standing prediction based on a phenomenological model for ferrimagnetic
systems. The field induced changes across Tcomp leave an imprint of a
quasi-phase transition in the heat capacity data. Magneto-resistance (\Delta R
/ R vs T) has an oscillatory response, in which the changes across Tc and Tcomp
can be recognized.


title: Evidence of Low Dimensional Chaos in Glow Curves of Thermoluminescence

abstract:
  Electron trapping following exposition to ionising radiations and consequent
electron release during variation of temperature in solids represent processes
happening at the quantum microphysical level. The interesting feature of the
thermally stimulated process, that in fact deserves further investigation, is
that the dynamic of electrons release during, variation of the temperature,
here examined through the so called thermoluminescent Glow Curve, evidences
chaotic and fractal regimes. Phase space reconstruction, Correlation Dimension,
largest Lyapunov exponent, Recurrence Quantification Analysis(RQA) and fractal
dimension analysis, developed by calculation of Hurst exponent, are performed
on three samples. The results unequivocally fix that Glow Curves respond to a
chaotic regime. RQA supports such results revealing the inner structure of Glow
Curve signals in relation to their properties of recurrence, determinism and
intermittency signed from laminarity as well as chaos-chaos and chaos order
transitions.


title:
Decision trees are PAC-learnable from most product distributions: a
  smoothed analysis

abstract:
  We consider the problem of PAC-learning decision trees, i.e., learning a
decision tree over the n-dimensional hypercube from independent random labeled
examples. Despite significant effort, no polynomial-time algorithm is known for
learning polynomial-sized decision trees (even trees of any super-constant
size), even when examples are assumed to be drawn from the uniform distribution
on {0,1}^n. We give an algorithm that learns arbitrary polynomial-sized
decision trees for {\em most product distributions}. In particular, consider a
random product distribution where the bias of each bit is chosen independently
and uniformly from, say, [.49,.51]. Then with high probability over the
parameters of the product distribution and the random examples drawn from it,
the algorithm will learn any tree. More generally, in the spirit of smoothed
analysis, we consider an arbitrary product distribution whose parameters are
specified only up to a [-c,c] accuracy (perturbation), for an arbitrarily small
positive constant c.


title:
Observability of glueball spectrum in QCD and the width of $\sigma$
  resonance

abstract:
  We prove a theorem in QCD stating that in the limit of strong coupling,
$g\to\infty$, the observed spectrum of glueballs in QCD is the same of a pure
Yang-Mills theory, being mixing effects due to the next-to-leading order. A
full effective theory for QCD is obtained and the width of the $\sigma$
resonance decay is straightforwardly computed. This appears as the lowest
glueball state. Vacuum gluon condensate is computed that consistently support
studies on the identification of this meson as a glueball.


title: The Casimir effect: from quantum to critical fluctuations

abstract:
  The Casimir effect in quantum electrodynamics (QED) is perhaps the best-known
example of fluctuation-induced long-ranged force acting on objects (conducting
plates) immersed in a fluctuating medium (quantum electromagnetic field in
vacuum). A similar effect emerges in statistical physics, where the force
acting, e.g., on colloidal particles immersed in a binary liquid mixture is
affected by the classical thermal fluctuations occurring in the surrounding
medium. The resulting Casimir-like force acquires universal features upon
approaching a critical point of the medium and becomes long-ranged at
criticality. In turn, this universality allows one to investigate theoretically
the temperature dependence of the force via representative models and to
stringently test the corresponding predictions in experiments. In contrast to
QED, the Casimir force resulting from critical fluctuations can be easily tuned
with respect to strength and sign by surface treatments and temperature
control. We present some recent advances in the theoretical study of the
universal properties of the critical Casimir force arising in thin films. The
corresponding predictions compare very well with the experimental results
obtained for wetting layers of various fluids. We discuss how the Casimir force
between a colloidal particle and a planar wall immersed in a binary liquid
mixture has been measured with femto-Newton accuracy, comparing these
experimental results with the corresponding theoretical predictions.


title: Gene-network inference by message passing

abstract:
  The inference of gene-regulatory processes from gene-expression data belongs
to the major challenges of computational systems biology. Here we address the
problem from a statistical-physics perspective and develop a message-passing
algorithm which is able to infer sparse, directed and combinatorial regulatory
mechanisms. Using the replica technique, the algorithmic performance can be
characterized analytically for artificially generated data. The algorithm is
applied to genome-wide expression data of baker's yeast under various
environmental conditions. We find clear cases of combinatorial control, and
enrichment in common functional annotations of regulated genes and their
regulators.


title: On parton distributions in a photon gas

abstract:
  In some cases it may be useful to know parton distributions in a photon gas.
This may be relevant, e.g., for the analysis of interactions of high energy
cosmic ray particles with the cosmic microwave background radiation. The latter
can be considered as a gas of photons with an almost perfect blackbody
spectrum. An approach to finding such parton distributions is described. The
survival probability of ultra-high energy neutrinos traveling through this
radiation is calculated.


title: Entanglement concentration after a multi-interactions channel

abstract:
  Different procedures have been developed in order to recover entanglement
after propagation over a noisy channel. Besides a certain amount of noise,
entanglement is completely lost and the channel is called entanglement
breaking. Here we investigate both theoretically and experimentally an
entanglement concentration protocol for a mixed three-qubit state outgoing from
a strong linear coupling of two-qubit maximally entangled polarization state
with another qubit in a completely mixed state. Thanks to such concentration
procedure, the initial entanglement can be probabilistically recovered.
Furthermore, we analyse the case of sequential linear couplings with many
depolarized photons showing that thanks to the concentration a full recovering
of entanglement is still possible.


title:
Direct Evidence for Conformal Invariance of Avalanche Frontier in
  Sandpile Models

abstract:
  Appreciation of Stochastic Loewner evolution (SLE$_\kappa$), as a powerful
tool to check for conformal invariant properties of geometrical features of
critical systems has been rising. In this paper we use this method to check
conformal invariance in sandpile models. Avalanche frontiers in Abelian
sandpile model (ASM) are numerically shown to be conformally invariant and can
be described by SLE with diffusivity $\kappa=2$. This value is the same as
value obtained for loop erased random walks (LERW). The fractal dimension and
Schramm's formula for left passage probability also suggest the same result. We
also check the same properties for Zhang's sandpile model.


title: Inference algorithms for gene networks: a statistical mechanics analysis

abstract:
  The inference of gene regulatory networks from high throughput gene
expression data is one of the major challenges in systems biology. This paper
aims at analysing and comparing two different algorithmic approaches. The first
approach uses pairwise correlations between regulated and regulating genes; the
second one uses message-passing techniques for inferring activating and
inhibiting regulatory interactions. The performance of these two algorithms can
be analysed theoretically on well-defined test sets, using tools from the
statistical physics of disordered systems like the replica method. We find that
the second algorithm outperforms the first one since it takes into account
collective effects of multiple regulators.


title: Generalized quantum potentials in scale relativity

abstract:
  We first recall that the system of fluid mechanics equations (Euler and
continuity) that describes a fluid in irrotational motion subjected to a
generalized quantum potential (in which the constant is no longer reduced to
the standard quantum constant hbar) is equivalent to a generalized Schrodinger
equation. Then we show that, even in the case of the presence of vorticity, it
is also possible to obtain, for a large class of systems, a Schrodinger-like
equation of the vectorial field type from the continuity and Euler equations
including a quantum potential. The same kind of transformation also applies to
a classical charged fluid subjected to an electromagnetic field and to an
additional potential having the form of a quantum potential. Such a fluid can
therefore be described by an equation of the Ginzburg-Landau type, and is
expected to show some superconducting-like properties. Moreover, a Schrodinger
form can be obtained for the fluctuating rotational motion of a solid. In this
case the mass is replaced by the tensor of inertia, and a generalized form of
the quantum potential is derived. We finally reconsider the case of a standard
diffusion process, and we show that, after a change of variable, the diffusion
equation can also be given the form of a continuity and Euler system including
an additional potential energy. Since this potential is exactly the opposite of
a quantum potential, the quantum behavior may be considered, in this context,
as an anti-diffusion.


title: Weak decays of heavy hadron molecules involving the f0(980)

abstract:
  We study weak decays of the charm- and bottom-strange mesons Ds0*(2317),
Ds1(2460), Bs0*(5725) and Bs1(5778) with f0(980) in the final state by assuming
a hadronic molecule interpretation for their structures. Since in the proposed
framework the initial and final states are occupied by hadronic molecules, the
predictions for observables can provide a sensitive tool to further test the
hadronic molecule structure in future experiments.


title: Gibbs' theorem for open systems with incomplete statistics

abstract:
  Gibbs' theorem, which is originally intended for canonical ensembles with
complete statistics has been generalized to open systems with incomplete
statistics. As a result of this generalization, it is shown that the stationary
equilibrium distribution of inverse power law form associated with the
incomplete statistics has maximum entropy even for open systems with energy or
matter influx. The renormalized entropy definition given in this paper can also
serve as a measure of self-organization in open systems described by incomplete
statistics.


title:
Th\'eor\`emes d'\'equidistribution pour les syst\`emes dynamiques
  d'origine arithm\'etique

abstract:
  This survey article is about algebraic dynamics. It is mainly concerned by
the arithmetic equidistribution theorems featured by dynamical systems. The
contents are: - heights - algebraic dynamics, conjectures - equidistribution
theorem on the projective line (after Bilu and Baker). It was written for the
sesion 2006 of \'Etats de la recherche, Syst\`emes dynamiques polynomiaux.


title:
Correlation between the spatial distribution of circumstellar disks and
  massive stars in the young open cluster NGC 6611. II: Cluster members
  selected with Spitzer/IRAC

abstract:
  Context: the observations of the proplyds in the Orion Nebula Cluster,
showing clear evidence of ongoing photoevaporation, have provided a clear proof
about the role of the externally induced photoevaporation in the evolution of
circumstellar disks. NGC 6611 is an open cluster suitable to study disk
photoevaporation, thanks to its large population of massive members and of
stars with disk. In a previous work, we obtained evidence of the influence of
the strong UV field generated by the massive cluster members on the evolution
of disks around low-mass Pre-Main Sequence members. That work was based on a
multi-band BVIJHK and X-ray catalog purposely compiled to select the cluster
members with and without disk. Aims: in this paper we complete the list of
candidate cluster members, using data at longer wavelengths obtained with
Spitzer/IRAC, and we revisit the issue of the effects of UV radiation on the
evolution of disks in NGC 6611. Methods: we select the candidate members with
disks of NGC 6611, in a field of view of 33'x34' centered on the cluster, using
IRAC color-color diagrams and suitable reddening-free color indices. Besides,
using the X-ray data to select Class III cluster members, we estimate the disks
frequency vs. the intensity of the incident radiation emitted by massive
members. Results: we identify 458 candidate members with circumstellar disks,
among which 146 had not been revealed in our previous work. Comparing of the
various color indices we used to select the cluster members with disk, we claim
that they detect the excesses due to the emission of the same physical region
of the disk: the inner rim at the dust sublimation radius. Our new results
confirm that UV radiation from massive stars affects the evolution of nearby
circumstellar disks.


title:
Prompt photon photoproduction at HERA within the framework of the quark
  Reggeization hypothesis

abstract:
  We study the inclusive production of isolated prompt photons within the
framework of the quasi-multi-Regge-kinematic approach, applying the quark
Reggeization hypothesis. We describe accurately and without free parameters the
transverse momentum and pseudorapidity spectra of prompt photons in the
inclusive photoproduction at the HERA Collider. It is shown that the main
mechanism of the inclusive prompt photon production in the gamma p collisions
is the fusion of a Reggeized quark (antiquark) from the proton and a collinear
antiquark (quark) from the photon into a photon, via the effective
Reggeon-quark-gamma vertex. The fragmentation of the quark, which is produced
via the gamma-Reggeon-quark and quark-Reggeon-quark vertices, into a photon is
strongly suppressed by the isolation cone condition and it gives a significant
contribution in the region of a large negative pseudorapidity only. At the
stage of numerical calculations we use the Kimber-Martin-Ryskin prescription
for unintegrated quark and gluon distribution functions, with the following
collinear parton densities as input: MRST for a proton and GRV for a photon.


title:
Lectures on height zeta functions: At the confluence of algebraic
  geometry, algebraic number theory, and analysis

abstract:
  This is a survey on the theory of height zeta functions, written on the
occasion of a French-Japanese winter school, held in Miura (Kanagawa, Japan) in
Jan. 2008. It does not presuppose much knowledge in algebraic geometry. The
last chapter of the survey explains recent results obtained in collaboration
with Yuri Tschinkel concerning asymptotics of volumes of height balls in
analytic geometry over local fields, or in adelic spaces.


title: Dynamical properties of dipolar Fermi gases

abstract:
  We investigate dynamical properties of a one-component Fermi gas with
dipole-dipole interaction between particles. Using a variational function based
on the Thomas-Fermi density distribution in phase space representation, the
total energy is described by a function of deformation parameters in both real
and momentum space. Various thermodynamic quantities of a uniform dipolar Fermi
gas are derived, and then instability of this system is discussed. For a
trapped dipolar Fermi gas, the collective oscillation frequencies are derived
with the energy-weighted sum rule method. The frequencies for the monopole and
quadrupole modes are calculated, and softening against collapse is shown as the
dipolar strength approaches the critical value. Finally, we investigate the
effects of the dipolar interaction on the expansion dynamics of the Fermi gas
and show how the dipolar effects manifest in an expanded cloud.


title: Self-organization in nonadditive systems with external noise

abstract:
  A nonadditive generalization of Klimontovich's S-theorem [G. B. Bagci, Int.J.
Mod. Phys. B 22, 3381 (2008)] has recently been obtained by employing Tsallis
entropy. This general version allows one to study physical systems whose
stationary distributions are of the inverse power law in contrast to the
original S-theorem, which only allows exponential stationary distributions. The
nonadditive S-theorem has been applied to the modified Van der Pol oscillator
with inverse power law stationary distribution. By using nonadditive S-theorem,
it is shown that the entropy decreases as the system is driven out of
equilibrium, indicating self-organization in the system. The allowed values of
the nonadditivity index $q$ are found to be confined to the regime (0.5,1].


title:
Duality considerations about the Maxwell-Podolsky theory through the
  symplectic embedding formalism and spectrum analysis

abstract:
  We find the dual equivalent (gauge invariant) version of the Maxwell theory
in D=4 with a Proca-like mass term by using the symplectic embedding method.
The dual theory obtained (Maxwell-Podolsky) includes a higher-order derivative
term and preserve the gauge symmetry. We also furnish an investigation of the
pole structure of the vector propagator by the residue matrix which considers
the eventual existence of the negative-norm of the theory.


title: The Misfit Strain Critical Point in the 3D Phase Diagrams of Cuprates

abstract:
  At the time of writing, data have been reported on several hundred different
cuprates materials, of which a substantial fraction show superconductivity at
temperatures as high as 130 K. The existence of several competing phases with
comparable energy shows up in different ways in different materials, therefore
it has not been possible to converge toward a universal theory for high Tc
superconductivity. With the aim to find a unified description the
Aeppli-Bianconi 3D phase diagram of cuprates has been proposed where the
superlattice misfit strain (eta) is the third variable beyond doping (delta)
and temperature T. The 3D phase diagrams for the magnetic order, and for the
superconducting order extended to all cuprates families are described. We
propose a formula able to describe the Tc (delta,eta) surface, this permits to
identify the stripe quantum critical point at (delta)c=1/8 and (eta)c =7percent
which is associated with the incommensurate to commensurate stripe phase
transition, controlled by the misfit strain.


title:
Rheology, Structure and Dynamics of Colloid-Polymer Mixtures: from
  Liquids to Gels

abstract:
  We investigated the viscoelastic properties of colloid-polymer mixtures at
intermediate colloid volume fraction and varying polymer concentrations,
thereby tuning the attractive interactions. Within the examined range of
polymer concentrations, the samples ranged from fluids to gels. Already in the
liquid phase the viscoelastic properties significantly changed when approaching
the gelation boundary, indicating the formation of clusters and transient
networks. This is supported by an increasing correlation length of the density
fluctuations, observed by static light scattering and microscopy. At the same
time, the correlation function determined by dynamic light scattering
completely decays, indicating the absence of dynamical arrest. Upon increasing
the polymer concentration beyond the gelation boundary, the rheological
properties changed qualitatively again, now they are consistent with the
formation of colloidal gels. Our experimental results, namely the location of
the gelation boundary as well as the elastic (storage) and viscous (loss)
moduli, are compared to different theoretical models. These include
consideration of the escape time as well as predictions for the viscoelastic
moduli based on scaling relations and Mode Coupling Theories (MCT).


title: Bose-Einstein condensation of magnons under incoherent pumping

abstract:
  Bose-Einstein condensation in a gas of magnons pumped by an incoherent
pumping source is experimentally studied at room temperature. We demonstrate
that the condensation can be achieved in a gas of bosons under conditions of
incoherent pumping. Moreover, we show the critical transition point is almost
independent of the frequency spectrum of the pumping source and is solely
determined by the density of magnons. The electromagnetic power radiated by the
magnon condensate was found to scale quadratically with the pumping power,
which is in accordance with the theory of Bose-Einstein condensation in magnon
gases.


title: High Scale Physics Connection to LHC Data

abstract:
  The existing data appears to provide hints of an underlying high scale
theory. These arise from the gauge coupling unification, from the smallness of
the neutrino masses, and via a non-vanishing muon anomaly. An overview of high
scale models is given with a view to possible tests at the Large Hadron
Collider. Specifically we discuss here some generic approaches to deciphering
their signatures. We also consider an out of the box possibility of a four
generation model where the fourth generation is a mirror generation rather than
a sequential generation. Such a scenario can lead to some remarkably distinct
signatures at the LHC.


title:
Dependence of the critical temperature on the Higgs field
  reparametrization

abstract:
  We show that, despite of the reparametrization symmetry of the Lagrangian
describing the interaction between a scalar field and gauge vector bosons, the
dynamics of the Higgs mechanism is really affected by the representation gauge
chosen for the Higgs field. Actually, we find that, varying the parametrization
for the two degrees of freedom of the complex scalar field, we obtain different
expressions for the Higgs mass: in its turn this entails different expressions
for the critical temperatures, ranging from zero to a maximum value, as well as
different expressions for other basic thermodynamical quantities.


title:
EcoTRADE - a multi player network game of a tradable permit market for
  biodiversity credits

abstract:
  EcoTRADE is a multi player network game of a virtual biodiversity credit
market. Each player controls the land use of a certain amount of parcels on a
virtual landscape. The biodiversity credits of a particular parcel depend on
neighboring parcels, which may be owned by other players. The game can be used
to study the strategies of players in experiments or classroom games and also
as a communication tool for stakeholders participating in credit markets that
include spatially interdependent credits.


title:
Asymptotic Behaviour and Artinian Property of Graded Local Cohomology
  Modules

abstract:
  In this paper, considering the difference between the finiteness dimension
and cohomological dimension for a finitely generated module, we investigate the
asymptotic behavior of grades of components of graded local cohomology modules
with respect to irrelevant ideal; as long as we study some artinian and
tameness property of such modules.


title:
Predicted Signatures at the LHC from U(1) Extensions of the Standard
  Model

abstract:
  We discuss the $U(1)_X$ extensions of the standard model with focus on the
Stueckelberg mechanism for mass growth for the extra $U(1)_X$ gauge boson. The
assumption of an axionic connector field which carries dual U(1) quantum
numbers, i.e., quantum numbers for the hypercharge $U(1)_Y$ and for the hidden
sector gauge group $U(1)_X$, allows a non-trivial mixing between the mass
growth for the neutral gauge vector bosons in the $SU(2)_L\times U(1)_Y$ sector
and the mass growth for the vector boson by the \st mechanism in the $U(1)_X$
sector. This results in an extra $Z'$ which can be very narrow, but still
detectable at the Large Hadron Collider (LHC). The $U(1)_X$ extension of the
minimal supersymmetric standard model is also considered and the role of the
Fayet-Illiopoulos term in such an extension discussed. The $U(1)_X$ extensions
of the SM and of the MSSM lead to new candidates for dark matter.


title: Generation of Total Angular Momentum Eigenstates in Remote Qubits

abstract:
  We propose a scheme enabling the universal coupling of angular momentum of
$N$ remote noninteracting qubits using linear optical tools only. Our system
consists of $N$ single-photon emitters in a $\Lambda$-configuration that are
entangled among their long-lived ground-state qubits through suitably designed
measurements of the emitted photons. In this manner, we present an
experimentally feasible algorithm that is able to generate any of the $2^N$
symmetric and nonsymmetric total angular momentum eigenstates spanning the
Hilbert space of the $N$-qubit compound.


title:
Ideal barriers to polarization reversal and domain-wall motion in
  strained ferroelectric thin films

abstract:
  The ideal intrinsic barriers to domain switching in c-phase PbTiO_3 (PTO),
PbZrO_3 (PZO), and PbZr_{1-x}Ti_xO_3 (PZT) are investigated via
first-principles computational methods. The effects of epitaxial strain on the
atomic structure, ferroelectric response, barrier to coherent domain reversal,
domain-wall energy, and barrier to domain-wall translation are studied. It is
found that PTO has a larger polarization, but smaller energy barrier to domain
reversal, than PZO. Consequentially the idealized coercive field is over two
times smaller in PTO than PZO. The Ti--O bond length is more sensitive to
strain than the other bonds in the crystals. This results in the polarization
and domain-wall energy in PTO having greater sensitivity to strain than in PZO.
Two ordered phases of PZT are considered, the rock-salt structure and a (100)
PTO/PZO superlattice. In these simple structures we find that the ferroelectric
properties do not obey Vergard's law, but instead can be approximated as an
average over individual 5-atom unit cells.


title: Nonlocal symmetries for bilinear equations and their applications

abstract:
  In this paper, nonlocal symmetries for the bilinear KP and bilinear BKP
equations are re-studied. Two arbitrary parameters are introduced in these
nonlocal symmetries by considering gauge invariance of the bilinear KP and
bilinear BKP equations under the transformation $f\longrightarrow
fe^{ax+by+ct}$. By expanding these nonlocal symmetries in powers of each of two
parameters, we have derived two types of bilinear NKP hierarchies and two types
of bilinear NBKP hierarchies. An impressive observation is that bilinear
positive and negative KP and BKP hierarchies may be derived from the same
nonlocal symmetries for the KP and BKP equations. Besides, as two concrete
examples, we have deived bilinear B\"acklund transformations for $t_{-2}$-flow
of the NKP hierarchy and $t_{-1}$-flow of the NBKP hierarchy. All these results
have made it clear that more nice integrable properties would be found for
these obtained NKP hierarchies and NBKP hierarchies. Since KP and BKP
hierarchies have played an essential role in soliton theory, we believe that
the bilinear NKP and NBKP hierarchies will have their right place in this
field.


title: Symmetric identities for Euler polynomials

abstract:
  In this paper we establish two symmetric identities on sums of products of
Euler polynomials.


title:
Picosecond Timing Resolution Detection of Gamma Photons Utilizing
  Microchannel-plate Detectors: Experimental Tests of Quantum Nonlocality and
  Photon Localization

abstract:
  The concept and subsequent experimental verification of the proportionality
between pulse amplitude and detector transit time for microchannel plate
detectors is presented. This discovery has led to considerable improvement in
the overall timing resolution for detection of high energy gamma photons.
Utilizing a 22Na positron source, a full width half maximum (FWHM) timing
resolution of 138 ps has been achieved. This FWHM includes detector
transit-time spread for both chevron-stack type detectors, timing spread due to
uncertainties in annihilation location, all electronic uncertainty, and any
remaining quantum mechanical uncertainty. The first measurement of the minimum
quantum uncertainty in the time interval between detection of the two
annihilation photons is reported. The experimental results give strong evidence
against instantaneous spatial-localization of gamma photons due to
measurement-induced nonlocal quantum wave-function collapse. The experimental
results are also the first that imply momentum is conserved only after the
quantum uncertainty in time has elapsed [H. Yukawa, Proc. Phys. -Math. Soc.
Japan, 17, 48 (1935)].


title:
Prospects for Detecting Neutrino Signals from Annihilating/Decaying Dark
  Matter to Account for the PAMELA and ATIC results

abstract:
  Recent PAMELA data show that positron fraction has an excess above several
GeV while anti-proton one is not. Moreover ATIC data indicates that
electron/positron flux have a bump from 300 GeV to 800 GeV. Both annihilating
dark matter (DM) with large boost factor and decaying DM with the life around $
10^{26} s$ can account for the PAMELA and ATIC observations if their main final
products are charged leptons ($e$, $\mu$ and $\tau$). In this work, we
calculated the neutrino flux arising from $\mu$ and $\tau$ which originate from
annihilating/decaying DM, and estimated the final muon rate in the neutrino
telescopes, namely Antares and IceCube. Given the excellent angular resolution,
Antares and IceCube are promising to discover the neutrino signals from
Galactic center and/or large DM subhalo in annihilating DM scenario, but very
challenging in decaying DM scenario.


title: The two uniform infinite quadrangulations of the plane have the same law

abstract:
  We prove that the uniform infinite random quadrangulations defined
respectively by Chassaing-Durhuus and Krikun have the same distribution.


title: Sigma model effective action for strong localization

abstract:
  Bose gas in a random external field is considered. The sigma model like
effective action both for weak and strong random fields compared with the
interaction between particles is derived by averaging over the random field and
integration over the quantum fluctuations in the framework of the
Keldysh-Schwinger technique for irreversible processes. Using this effective
action the properties of the system in strongly fluctuating random field are
analyzed.


title: Secret Broadcasting of GHZ type state

abstract:
  Here we described a protocol by which one can broadcast GHZ-type states
secretly. We have done this with the help of a cloning machine followed by
subsequent measurements. We also made a comparative study of the amount of
residual tangle present in these entangled states, obtained as outputs of the
measurements.


title:
R-process nucleosynthesis calculations with complete nuclear physics
  input

abstract:
  The r-process constitutes one of the major challenges in nuclear
astrophysics. Its astrophysical site has not yet been identified but there is
observational evidence suggesting that at least two possible sites should
contribute to the solar system abundance of r-process elements and that the
r-process responsible for the production of elements heavier than Z=56 operates
quite robustly producing always the same relative abundances. From the
nuclear-physics point of view the r-process requires the knowledge of a large
number of reaction rates involving exotic nuclei. These include neutron capture
rates, beta-decays and fission rates, the latter for the heavier nuclei
produced in the r-process. We have developed for the first time a complete
database of reaction rates that in addition to neutron-capture rates and
beta-decay half-lives includes all possible reactions that can induce fission
(neutron-capture, beta-decay and spontaneous fission) and the corresponding
fission yields. In addition, we have implemented these reaction rates in a
fully implicit reaction network. We have performed r-process calculations for
the neutrino-driven wind scenario to explore whether or not fission can
contribute to provide a robust r-process pattern.


title: Phase transitions and ordering of confined dipolar fluids

abstract:
  We apply a modified mean-field density functional theory to determine the
phase behavior of Stockmayer fluids in slitlike pores formed by two walls with
identical substrate potentials. Based on the Carnahan-Starling equation of
state, a fundamental-measure theory is employed to incorporate the effects of
short-ranged hard sphere - like correlations while the long-ranged
contributions to the fluid interaction potential are treated perturbatively.
The liquid-vapor, ferromagnetic liquid - vapor, and ferromagnetic liquid -
isotropic liquid first-order phase separations are investigated. The local
orientational structure of the anisotropic and inhomogeneous ferromagnetic
liquid phase is also studied. We discuss how the phase diagrams are shifted and
distorted upon varying the pore width.


title: Quantum Giambelli formulas for isotropic Grassmannians

abstract:
  Let X be a symplectic or odd orthogonal Grassmannian which parametrizes
isotropic subspaces in a vector space equipped with a nondegenerate (skew)
symmetric form. We prove quantum Giambelli formulas which express an arbitrary
Schubert class in the small quantum cohomology ring of X as a polynomial in
certain special Schubert classes, extending the cohomological Giambelli
formulas of arXiv:0811.2781.


title: SMBH feeding and star formation in massive accretion discs

abstract:
  Galactic nuclei are unique laboratories for the study of processes connected
with the accretion of gas onto supermassive black holes. At the same time, they
represent challenging environments from the point of view of stellar dynamics
due to their extreme densities and masses involved. There is a growing evidence
about the importance of the mutual interaction of stars with gas in galactic
nuclei. Gas rich environment may lead to stellar formation which, on the other
hand, may regulate accretion onto the central mass. Gas in the form of massive
torus or accretion disc further influences stellar dynamics in the central
parsec either via gravitational or hydrodynamical interaction. Eccentricity
oscillations on one hand and energy dissipation on the other hand lead to
increased rate of infall of stars into the supermassive black hole. Last, but
not least, processes related to the stellar dynamics may be detectable with
forthcoming gravitational waves detectors.


title:
Network Protection Codes: Providing Self-healing in Autonomic Networks
  Using Network Coding

abstract:
  Agile recovery from link failures in autonomic communication networks is
essential to increase robustness, accessibility, and reliability of data
transmission. However, this must be done with the least amount of protection
resources, while using simple management plane functionality. Recently, network
coding has been proposed as a solution to provide agile and cost efficient
network self-healing against link failures, in a manner that does not require
data rerouting, packet retransmission, or failure localization, hence leading
to simple control and management planes. To achieve this, separate paths have
to be provisioned to carry encoded packets, hence requiring either the addition
of extra links, or reserving some of the resources for this purpose.
  In this paper we introduce autonomic self-healing strategies for autonomic
networks in order to protect against link failures. The strategies are based on
network coding and reduced capacity, which is a technique that we call network
protection codes (NPC). In these strategies, an autonomic network is able to
provide self-healing from various network failures affecting network operation.
The techniques improve service and enhance reliability of autonomic
communication.
  Network protection codes are extended to provide self-healing from multiple
link failures in autonomic networks. We provide implementation aspects of the
proposed strategies. We present bounds and network protection code
constructions. Finally, we study the construction of such codes over the binary
field. The paper also develops an Integer Linear Program formulation to
evaluate the cost of provisioning connections using the proposed strategies.


title: Sculpting the Vortex State of a Spinor BEC

abstract:
  We use Raman-detuned laser pulses to achieve spatially-varying control of the
amplitude and phase of the spinor order parameter of a Bose-Einstein
condensate. We present experimental results confirming precise radial and
azimuthal control of amplitude and phase during the creation of
vortex-antivortex superposition states.


title:
Real space first-principles derived semiempirical pseudopotentials
  applied to tunneling magnetoresistance

abstract:
  In this letter we present a real space density functional theory (DFT)
localized basis set semi-empirical pseudopotential (SEP) approach. The method
is applied to iron and magnesium oxide, where bulk SEP and local spin density
approximation (LSDA) band structure calculations are shown to agree within
approximately 0.1 eV. Subsequently we investigate the qualitative
transferability of bulk derived SEPs to Fe/MgO/Fe tunnel junctions. We find
that the SEP method is particularly well suited to address the tight binding
transferability problem because the transferability error at the interface can
be characterized not only in orbital space (via the interface local density of
states) but also in real space (via the system potential). To achieve a
quantitative parameterization, we introduce the notion of ghost semi-empirical
pseudopotentials extracted from the first-principles calculated Fe/MgO bonding
interface. Such interface corrections are shown to be particularly necessary
for barrier widths in the range of 1 nm, where interface states on opposite
sides of the barrier couple effectively and play a important role in the
transmission characteristics. In general the results underscore the need for
separate tight binding interface and bulk parameter sets when modeling
conduction through thin heterojunctions on the nanoscale.


title: Dewetting dynamics of stressed viscoelastic thin polymer films

abstract:
  Ultrathin polymer films that are produced e.g. by spin-coating are believed
to be stressed since polymers are 'frozen in' into out-of-equilibrium
configurations during this process. In the framework of a viscoelastic thin
film model, we study the effects of lateral residual stresses on the dewetting
dynamics of the film. The temporal evolution of the height profiles and the
velocity profiles inside the film as well as the dissipation mechanisms are
investigated in detail. Both the shape of the profiles and the importance of
frictional dissipation vs. viscous dissipation inside the film are found to
change in the course of dewetting. The interplay of the non-stationary
profiles, the relaxing initial stress and changes in the dominance of the two
dissipation mechanisms caused by nonlinear friction with the substrate is
responsible for the rich behavior of the system. In particular, our analysis
sheds new light on the occurrence of the unexpected maximum in the rim width
obtained recently in experiments on PS-PDMS systems.


title: The Formation and Survival of Discs in a Lambda-CDM Universe

abstract:
  We study the formation of galaxies in a Lambda-CDM Universe using high
resolution hydrodynamical simulations with a multiphase treatment of gas,
cooling and feedback, focusing on the formation of discs. Our simulations
follow eight haloes similar in mass to the Milky Way and extracted from a large
cosmological simulation without restriction on spin parameter or merger
history. This allows us to investigate how the final properties of the
simulated galaxies correlate with the formation histories of their haloes. We
find that, at z = 0, none of our galaxies contain a disc with more than 20 per
cent of its total stellar mass. Four of the eight galaxies nevertheless have
well-formed disc components, three have dominant spheroids and very small
discs, and one is a spheroidal galaxy with no disc at all. The z = 0 spheroids
are made of old stars, while discs are younger and formed from the inside-out.
Neither the existence of a disc at z = 0 nor the final disc-to-total mass ratio
seems to depend on the spin parameter of the halo. Discs are formed in haloes
with spin parameters as low as 0.01 and as high as 0.05; galaxies with little
or no disc component span the same range in spin parameter. Except for one of
the simulated galaxies, all have significant discs at z > ~2, regardless of
their z = 0 morphologies. Major mergers and instabilities which arise when
accreting cold gas is misaligned with the stellar disc trigger a transfer of
mass from the discs to the spheroids. In some cases, discs are destroyed, while
in others, they survive or reform. This suggests that the survival probability
of discs depends on the particular formation history of each galaxy. A
realistic Lambda-CDM model will clearly require weaker star formation at high
redshift and later disc assembly than occurs in our models.


title:
Investigation of Superconducting Gap Structure in
  TbFeAsO$_{0.9}$F$_{0.1}$ using Point Contact Andreev Reflection

abstract:
  Bulk samples of TbFeAsO$_{0.9}$F$_{0.1}$ (T$_{c}$(on) = 50K) were measured by
point contact Andreev reflection spectroscopy. The spectra show unambiguous
evidence for multiple gap-like features plus the presence of high bias
shoulders. By measuring the spectra as a function of temperature with both gold
and superconducting niobium tips, we establish that the gap-like features are
associated with superconducting order parameter in this material. We discuss
whether the well defined zero bias conductance peak that we observe
infrequently is associated with a nodal superconducting order parameter.


title:
Discovery of Very High-Energy Gamma-Ray Radiation from the BL Lac 1ES
  0806+524

abstract:
  The high-frequency-peaked BL-Lacertae object \objectname{1ES 0806+524}, at
redshift z=0.138, was observed in the very-high-energy (VHE) gamma-ray regime
by VERITAS between November 2006 and April 2008. These data encompass the two-,
and three-telescope commissioning phases, as well as observations with the full
four-telescope array. \objectname{1ES 0806+524} is detected with a statistical
significance of 6.3 standard deviations from 245 excess events. Little or no
measurable variability on monthly time scales is found. The photon spectrum for
the period November 2007 to April 2008 can be characterized by a power law with
photon index $3.6 \pm 1.0_{\mathrm{stat}} \pm 0.3_{\mathrm{sys}}$ between
$\sim$300 GeV and $\sim$700 GeV. The integral flux above 300 GeV is
$(2.2\pm0.5_{\mathrm{stat}}\pm0.4_{\mathrm{sys}})\times10^{-12}\:\mathrm{cm}^{2}\:\mathrm{s}^{-1}$
which corresponds to 1.8% of the Crab Nebula flux. Non contemporaneous
multiwavelength observations are combined with the VHE data to produce a
broadband spectral energy distribution that can be reasonably described using a
synchrotron-self Compton model.


title:
In search of progenitors for supernova-less GRBs 060505 and 060614:
  re-examination of their afterglows

abstract:
  GRB060505 and GRB060614 are nearby long-duration gamma-ray bursts (LGRBs)
without accompanying supernovae (SNe) down to very strict limits. They thereby
challenge the conventional LGRB-SN connection and naturally give rise to the
question: are there other peculiar features in their afterglows which would
help shed light on their progenitors? To answer this question, we combine new
observational data with published data and investigate the multi-band temporal
and spectral properties of the two afterglows. We find that both afterglows can
be well interpreted within the framework of the jetted standard external shock
wave model, and that the afterglow parameters for both bursts fall well within
the range observed for other LGRBs. Hence, from the properties of the
afterglows there is nothing to suggest that these bursts should have another
progenitor than other LGRBs. Recently, Swift-discovered GRB080503 also has the
spike + tail structure during its prompt gamma-ray emission seemingly similar
to GRB060614. We analyse the prompt emission of this burst and find that this
GRB is actually a hard-spike + hard-tail burst with a spectral lag of
0.8$\pm$0.4 s during its tail emission. Thus, the properties of the prompt
emission of GRB060614 and GRB080503 are clearly different, motivating further
thinking of GRB classification. Finally we note that, whereas the progenitor of
the two SN-less bursts remains uncertain, the core-collapse origin for the
SN-less bursts would be quite certain if a wind-like environment can be
observationally established, e.g, from an optical decay faster than the X-ray
decay in the afterglow's slow cooling phase.


title: Supersymmetry Without Prejudice

abstract:
  We begin an exploration of the physics associated with the general
CP-conserving MSSM with Minimal Flavor Violation, the pMSSM. The 19 soft SUSY
breaking parameters in this scenario are chosen so as to satisfy all existing
experimental and theoretical constraints assuming that the WIMP is a
conventional thermal relic, ie, the lightest neutralino. We scan this parameter
space twice using both flat and log priors for the soft SUSY breaking mass
parameters and compare the results which yield similar conclusions. Detailed
constraints from both LEP and the Tevatron searches play a particularly
important role in obtaining our final model samples. We find that the pMSSM
leads to a much broader set of predictions for the properties of the SUSY
partners as well as for a number of experimental observables than those found
in any of the conventional SUSY breaking scenarios such as mSUGRA. This set of
models can easily lead to atypical expectations for SUSY signals at the LHC.


title: Temperature versus acceleration: the Unruh effect for holographic models

abstract:
  We analyse the effect of velocity and acceleration on the temperature felt by
particles and strings in backgrounds relevant in holographic models. First, we
compare accelerated strings and strings at finite temperature. We find that for
fixed Unruh temperature felt by the string endpoints, the screening length is
smaller for the accelerated Wilson loop than for the static one in a thermal
background of the same temperature; hence acceleration provides a "more
efficient" mechanism for melting of mesons. Secondly, we show that the
velocity-dependence of the screening length of the colour force, previously
obtained from a moving Wilson loop in a finite temperature background, is not
specific for the string, but is a consequence of the generic fact that an
observer which moves with constant velocity in a black hole background measures
a velocity-dependent temperature. Finally, we analyse accelerated particles and
strings in the AdS black hole background, and show that these feel a
temperature which increases as a function of time. As a byproduct of our
analysis we find a global Minkowski embedding for the planar AdS black hole.


title: Regularity results for stable-like operators

abstract:
  For $\alpha\in [1,2)$ we consider operators of the form $$L f(x)=\int_{R^d}
[f(x+h)-f(x)-1_{(|h|\leq 1)} \nabla f(x)\cdot h]
\frac{A(x,h)}{|h|^{d+\alpha}}$$ and for $\alpha\in (0,1)$ we consider the same
operator but where the $\nabla f$ term is omitted. We prove, under appropriate
conditions on $A(x,h)$, that the solution $u$ to $L u=f$ will be in
$C^{\alpha+\beta}$ if $f\in C^\beta$.


title: Mechanical and superfluid properties of dislocations in solid He4

abstract:
  Dislocations are shown to be smooth at zero temperature because of the
effective Coulomb-type interaction between kinks. Crossover to finite
temperature rougnehing is suggested to be a mechanism responsible for the
softening of \he4 shear modulus recently observed by Day and Beamish (Nature,
{\bf 450}, 853 (2007)). We discuss also that strong suppresion of superfuidity
along the dislocation core by thermal kinks can lead to locking in of the
mechanical and superfluid responses.


title:
Frying Doughnuts: What can the reprocessing of X-rays to IR tell us
  about the AGN environment?

abstract:
  Active galactic nuclei (AGN) produce vast amounts of high energy radiation
deep in their central engines. X-rays either escape the AGN or are absorbed and
re-emitted mostly as IR. By studying the dispersion in the ratio of observed
mid-IR luminosity to observed 2-10keV X-ray luminosity (R_{ir/x}) in AGN we can
investigate the reprocessing material (possibly a torus or donut of dust) in
the AGN central engine, independent of model assumptions. We studied the ratio
of observed mid-IR and 2-10keV X-ray luminosities in a heterogeneous sample of
245 AGN from the literature. We found that when we removed AGN with prominent
jets, ~90% of Type I AGN lay within a very tight dispersion in luminosity ratio
(1<R_{ir/x}<30). This implies that the AGN central engine is extremely uniform
and models of the physical AGN environment (e.g. cloud cover, turbulent disk,
opening angle of absorbing structures such as dusty tori) must span a very
narrow range of parameters. We also found that the far-IR(100um) to mid-IR
(12um) observed luminosity ratio is an effective descriminator between heavily
obscured AGN and relatively unobscured AGN.


title: Atomistic studies of transformation pathways and energetics in plutonium

abstract:
  One of the most challenging problems in understanding the structural phase
transformations in Pu is to determine the energetically favored, continuous
atomic pathways from one crystal symmetry to another. This problem involves
enumerating candidate pathways and studying their energetics to garner insight
into instabilities and energy barriers. The purpose of this work is to
investigate the energetics of two transformation pathways for the delta to
alpha' transformation in Pu that were recently proposed [Lookman et al., Phys.
Rev. Lett. 100:145504, 2008] on the basis of symmetry. These pathways require
the presence of either an intermediate hexagonal closed-packed (hcp) structure
or a simple hexagonal (sh) structure. A subgroup of the parent fcc and the
intermediate hexagonal structure, which has trigonal symmetry, facilitates the
transformation to the intermediate hcp or sh structure. Phonons then break the
translational symmetry from the intermediate hcp or sh structure to the final
monoclinic symmetry of the alpha' structure. We perform simulations using the
modified embedded atom method (MEAM) for Pu to investigate these candidate
pathways. Our main conclusion is that the path via hcp is energetically favored
and the volume change for both pathways essentially occurs in the second step
of the transformation, i.e. from the intermediate sh or hcp to the monoclinic
structure. Our work also highlights the deficiency of the current
state-of-the-art MEAM potential in capturing the anisotropy associated with the
lower symmetry monoclinic structure.


title: Module categories for permutation modular invariants

abstract:
  We show that a braided monoidal category C can be endowed with the structure
of a right (and left) module category over C \times C. In fact, there is a
family of such module category structures, and they are mutually isomorphic if
and only if C allows for a twist. For the case that C is premodular we compute
the internal End of the tensor unit of C, and we show that it is an Azumaya
algebra if C is modular. As an application to two-dimensional rational
conformal field theory, we show that the module categories describe the
permutation modular invariant for models based on the product of two identical
chiral algebras. It follows in particular that all permutation modular
invariants are physical.


title: Medium Effects in rho-Meson Photoproduction

abstract:
  We compute dilepton invariant mass spectra from the decays of rho mesons
produced by photon reactions off nuclei. Our calculations employ a realistic
model for the rho photoproduction amplitude on the nucleon which provides fair
agreement with measured cross sections. Medium effects are implemented via an
earlier constructed rho propagator based on hadronic many-body theory. At
incoming photon energies of 1.5 -3 GeV as used by the CLAS experiment at JLAB,
the average density probed for iron targets is estimated at about half
saturation density. At the pertinent rho-meson 3-momenta the predicted medium
effects on the rho propagator are rather moderate. The resulting dilepton
spectra approximately agree with recent CLAS data.