title: Phase Transition and Strong Predictability

abstract:
  The statistical mechanical interpretation of algorithmic information theory
(AIT, for short) was introduced and developed in our former work [K. Tadaki,
Local Proceedings of CiE 2008, pp.425-434, 2008], where we introduced the
notion of thermodynamic quantities into AIT. These quantities are real
functions of temperature T>0. The values of all the thermodynamic quantities
diverge when T exceeds 1. This phenomenon corresponds to phase transition in
statistical mechanics. In this paper we introduce the notion of strong
predictability for an infinite binary sequence and then apply it to the
partition function Z(T), which is one of the thermodynamic quantities in AIT.
We then reveal a new computational aspect of the phase transition in AIT by
showing the critical difference of the behavior of Z(T) between T=1 and T<1 in
terms of the strong predictability for the base-two expansion of Z(T).


title: Triple gear

abstract:
  A relatively common sight in graphic designs is a planar arrangement of three
gears in contact. However, since neighboring gears must rotate in opposite
directions, none of the gears can move. We give a non-planar, and non-frozen,
arrangement of three linked gears.


title:
Quantifying quark mass effects at the LHC: A study of pp -> b anti-b b
  anti-b + X at next-to-leading order

abstract:
  The production of four bottom quarks is an important benchmark channel for
Higgs analyses and searches for new physics at the LHC. We report on the
calculation of the next-to-leading order QCD corrections to the process pp -> b
anti-b b anti-b + X with the HELAC-NLO automated framework, and present results
for inclusive cross sections and differential distributions. We discuss the
impact of the higher-order corrections and, in particular, the effect of the
bottom quark mass. In addition, we provide an estimate of the theoretical
uncertainty from the variation of the renormalisation and factorisation scales
and the parton distribution functions. The results are obtained with a new
subtraction formalism for real radiation at next-to-leading order, implemented
in the HELAC-DIPOLES package.


title:
Ultranarrow-Band Photon Pair Source Compatible with Solid State Quantum
  Memories and Telecommunication Networks

abstract:
  We report on a source of ultranarrow-band photon pairs generated by widely
nondegenerate cavity-enhanced spontaneous down-conversion. The source is
designed to be compatible with Pr3+ solid state quantum memories and
telecommunication optical fibers, with signal and idler photons close to 606 nm
and 1436 nm, respectively. Both photons have a spectral bandwidth around 2 MHz,
matching the bandwidth of Pr3+ doped quantum memories. This source is ideally
suited for long distance quantum communication architectures involving solid
state quantum memories.


title: Exponentiable approach spaces

abstract:
  In this note we present a characterisation of exponentiable approach spaces
in terms of ultrafilter convergence.


title: Law Of Large Numbers For Random Dynamical Systems

abstract:
  We cosider random dynamical systems with randomly chosen jumps. The choice of
deterministic dynamical system and jumps depends on a position. We proove the
existence of an exponentially attractive invariant measure and the strong law
of large numbers.


title: Particular solutions to multidimensional PDEs with KdV-type nonlinearity

abstract:
  We consider a class of particular solutions to the (2+1)-dimensional
nonlinear partial differential equation (PDE) $u_t +\partial_{x_2}^n u_{x_1} -
u_{x_1} u =0$ (here $n$ is any integer) reducing it to the ordinary
differential equation (ODE). In a simplest case, $n=1$, the ODE is solvable in
terms of elementary functions. Next choice, $n=2$, yields the cnoidal waves for
the special case of Zakharov-Kuznetsov equation. The proposed method is based
on the deformation of the characteristic of the equation $u_t-uu_{x_1}=0$ and
might also be useful in study the higher dimensional PDEs with arbitrary linear
part and KdV-type nonlinearity (i.e. the nonlinear term is $u_{x_1} u$).


title: Precision measurement of D meson mass differences

abstract:
  Using three- and four-body decays of $D$ mesons produced in semileptonic
$b$-hadron decays, precision measurements of $D$ meson mass differences are
made together with a measurement of the $D^{0}$ mass. The measurements are
based on a dataset corresponding to an integrated luminosity of $1.0 fb^{-1}$
collected in $pp$ collisions at 7\,TeV. Using the decay $D^0 \rightarrow K^{+}
K^{-} K^{-} \pi^{+}$, the $D^0$ mass is measured to be $M(D^0) &=& 1864.75 \pm
0.15 \,({\rm stat}) \pm 0.11 \,({\rm syst}) \, \textrm{MeV/c^2}$. The mass
differences $M(D^{+}) - M(D^{0}) = 4.76 \pm 0.12 \,({\rm stat}) \pm 0.07
\,({\rm syst}) \, \textrm{MeV/c^2}$ and $M(D^{+}_s) - M(D^{+}) = 98.68 \pm 0.03
\,({\rm stat}) \pm 0.04 \,({\rm syst}) \, \textrm{MeV/c^2}$ are measured using
the $D^0 \rightarrow K^{+} K^{-} \pi^{+} \pi^{-}$ and $D^{+}_{(s)} \rightarrow
K^{+}K^{-} \pi^{+}$ modes.


title: Hidden Sector Photon Coupling of Resonant Cavities

abstract:
  Many beyond the standard model theories introduce light paraphotons, a
hypothetical spin-1 field that kinetically mixes with photons. Microwave cavity
experiments have traditionally searched for paraphotons via transmission of
power from an actively driven cavity to a passive receiver cavity, with the two
cavities separated by a barrier that is impenetrable to photons. We extend this
measurement technique to account for two-way coupling between the cavities and
show that the presence of a paraphoton field can alter the resonant frequencies
of the coupled cavity pair. We propose an experiment that exploits this effect
and uses measurements of a cavities resonant frequency to constrain the
paraphoton-photon mixing parameter, chi. We show that such an experiment can
improve sensitivity to chi over existing experiments for paraphoton masses less
than the resonant frequency of the cavity, and eliminate some of the most
common systematics for resonant cavity experiments.


title:
Stability of the classical type of relative equilibria of a rigid body
  in the J2 problem

abstract:
  The motion of a point mass in the J2 problem is generalized to that of a
rigid body in a J2 gravity field. The linear and nonlinear stability of the
classical type of relative equilibria of the rigid body, which have been
obtained in our previous paper, are studied in the framework of geometric
mechanics with the second-order gravitational potential. Non-canonical
Hamiltonian structure of the problem, i.e., Poisson tensor, Casimir functions
and equations of motion, are obtained through a Poisson reduction process by
means of the symmetry of the problem. The linear system matrix at the relative
equilibria is given through the multiplication of the Poisson tensor and
Hessian matrix of the variational Lagrangian. Based on the characteristic
equation of the linear system matrix, the conditions of linear stability of the
relative equilibria are obtained. The conditions of nonlinear stability of the
relative equilibria are derived with the energy-Casimir method through the
projected Hessian matrix of the variational Lagrangian. With the stability
conditions obtained, both the linear and nonlinear stability of the relative
equilibria are investigated in details in a wide range of the parameters of the
gravity field and the rigid body. We find that both the zonal harmonic J2 and
the characteristic dimension of the rigid body have significant effects on the
linear and nonlinear stability. Similar to the classical attitude stability in
a central gravity field, the linear stability region is also consisted of two
regions that are analogues of the Lagrange region and the DeBra-Delp region
respectively. The nonlinear stability region is the subset of the linear
stability region in the first quadrant that is the analogue of the Lagrange
region. Our results are very useful for the studies on the motion of natural
satellites in our solar system.


title: CKM matrix element Vcb in a QCD Potential model

abstract:
  We study the slope $\rho^{2}$ and curvature $C$ of Isgur Wise function for
the heavy-light mesons in general with particular emphasis on $B$ meson in a
QCD Potential model. The IW function is then used to compute the partial decay
width and branching ratio for the semileptonic decay of
$\left(B^{0}\rightarrow{D,D^{*}l\nu}\right)$. The computed value of the CKM
element $|V_{cb}|=0.040$ is found to be in agreement with the available data.


title:
Determination of Transverse Density Structuring from Propagating MHD
  Waves in the Solar Atmosphere

abstract:
  We present a Bayesian seismology inversion technique for propagating
magnetohydrodynamic (MHD) transverse waves observed in coronal waveguides. The
technique uses theoretical predictions for the spatial damping of propagating
kink waves in transversely inhomogeneous coronal waveguides. It combines wave
amplitude damping length scales along the waveguide with theoretical results
for resonantly damped propagating kink waves to infer the plasma density
variation across the oscillating structures. Provided the spatial dependence of
the velocity amplitude along the propagation direction is measured and the
existence of two different damping regimes is identified, the technique would
enable us to fully constrain the transverse density structuring, providing
estimates for the density contrast and its transverse inhomogeneity length
scale.


title:
Maximum Matching and Linear Programming in Fixed-Point Logic with
  Counting

abstract:
  We establish the expressibility in fixed-point logic with counting (FPC) of a
number of natural polynomial-time problems. In particular, we show that the
size of a maximum matching in a graph is definable in FPC. This settles an open
problem first posed by Blass, Gurevich and Shelah, who asked whether the
existence of perfect matchings in general graphs could be determined in the
more powerful formalism of choiceless polynomial time with counting. Our result
is established by showing that the ellipsoid method for solving linear programs
can be implemented in FPC. This allows us to prove that linear programs can be
optimised in FPC if the corresponding separation oracle problem can be defined
in FPC. On the way to defining a suitable separation oracle for the maximum
matching problem, we provide FPC formulas defining maximum flows and canonical
minimum cuts in capacitated graphs.


title: The theory and practice of Reedy categories

abstract:
  The goal of this paper is to demystify the role played by the Reedy category
axioms in homotopy theory. With no assumed prerequisites beyond a healthy
appetite for category theoretic arguments, we present streamlined proofs of a
number of useful technical results, which are well known to folklore but
difficult to find in the literature. While the results presented here are not
new, our approach to their proofs is somewhat novel. Specifically, we reduce
the much of the hard work involved to simpler computations involving weighted
colimits and Leibniz (pushout-product) constructions. The general theory is
developed in parallel with examples, which we use to prove that familiar
formulae for homotopy limits and colimits indeed have the desired properties.


title: Security Issues In Speech Watermarking for Information Transmission

abstract:
  The secure transmission of speech information is a significant issue faced by
many security professionals and individuals. By applying voice-encryption
technique any kind of encrypted sensitive speech data such as password can be
transmitted. But this has the serious disadvantage that by means of
cryptanalysis attack encrypted data can be compromised. Increasing the strength
of encryption/decryption results in an associated increased in the cost.
Additional techniques like stenography and digital watermarking can be used to
conceal information in an undetectable way in audio data. However this
watermarked audio data has to be send through unreliable media and an
eavesdropper might get hold of secret message and can also determine the
identity of a speaker who is sending the information since human voice contains
information based on its characteristics such as frequency, pitch, and energy.
This paper proposes Normalized Speech Watermarking technique. Speech signal is
normalized to hide the identity of the speaker who is sending the information
and then speech watermarking technique is applied on this normalized signal
that contains the message (password) so that what information is transmitted
should not be unauthorizedly revealed.


title:
Extension of Newton-Steffenssen method by Gejji-Jafari decomposition
  Technique for solving nonlinear equations

abstract:
  In this paper we extend Newton-Steffenssen method for solving nonlinear
equations, introduced by Sharma [J.R. Sharma, A composite third order
Newton-Steffenssen method for solving nonlinear equations, Appl. Math. Comput.
169 (2005), 242-246] by using the Gejji-Jafari decomposition technique. Several
numerical examples are given to illustrate the efficiency and performance of
this new method.


title:
Universal corrections to the entanglement entropy in gapped quantum spin
  chains: a numerical study

abstract:
  We carry out a numerical study of the bi-partite entanglement entropy in the
gapped regime of two paradigmatic quantum spin chain models: the Ising chain in
an external magnetic field and the anti-ferromagnetic XXZ model. The universal
scaling limit of these models is described by the massive Ising field theory
and the SU(2)-Thirring (sine-Gordon) model, respectively. We may therefore
exploit quantum field theoretical results to predict the behaviour of the
entropy. We numerically confirm that, in the scaling limit, corrections to the
saturation of the entropy at large region size are proportional to the Bessel
function K0(2mr) where m is a mass scale (the inverse correlation length) and r
the length of the region under consideration. The proportionality constant is
simply related to the number of particle types in the universal spectrum. This
was originally predicted in publications involving two of the current authors
for two-dimensional quantum field theories. Away from the universal region our
numerics suggest an entropic behaviour following quite closely the quantum
field theory prediction, except for extra dependencies on the correlation
length.


title: A Massive Pulsar in a Compact Relativistic Binary

abstract:
  Many physically motivated extensions to general relativity (GR) predict
significant deviations in the properties of spacetime surrounding massive
neutron stars. We report the measurement of a 2.01 +/- 0.04 solar mass pulsar
in a 2.46-hr orbit with a 0.172 +/- 0.003 solar mass white dwarf. The high
pulsar mass and the compact orbit make this system a sensitive laboratory of a
previously untested strong-field gravity regime. Thus far, the observed orbital
decay agrees with GR, supporting its validity even for the extreme conditions
present in the system. The resulting constraints on deviations support the use
of GR-based templates for ground-based gravitational wave detectors.
Additionally, the system strengthens recent constraints on the properties of
dense matter and provides insight to binary stellar astrophysics and pulsar
recycling.

categories: astro-ph.HE astro-ph.SR cond-mat.quant-gas gr-qc


title:
Radio-frequency electromagnetic field and vortex penetration in
  multilayered superconductors

abstract:
  A multilayered structure with a single superconductor layer and a single
insulator layer formed on a bulk superconductor is studied. General formulae
for the vortex-penetration field of the superconductor layer and the magnetic
field on the bulk superconductor, which is shielded by the superconductor and
insulator layers, are derived with a rigorous calculation of the magnetic field
attenuation in the multilayered structure. The achievable peak surface field
depends on the thickness and its material of the superconductor layer, the
thickness of the insulator layer and material of the bulk superconductor. The
calculation shows a good agreement with an experimental result. A combination
of the thicknesses of superconductor and insulator layers to enhance the field
limit can be given by the formulae for any given materials.


title: Quantum phase transitions in multileg spin ladders with ring exchange

abstract:
  Four-spin exchange interaction has been raising intriguing questions
regarding the exotic phase transitions it induces in two-dimensional quantum
spin systems. In this context, we investigate the effects of a cyclic four-spin
exchange in the quasi-1D limit by considering a general N-leg spin ladder. We
show by means of a low-energy approach that, depending on its sign, this ring
exchange interaction can engender either a staggered or a uniform dimerization
from the conventional phases of spin ladders. The resulting quantum phase
transition is found to be described by the SU(2)_N conformal field theory. This
result, as well as the fractional value of the central charge at the
transition, is further confirmed by a large-scale numerical study performed by
means of Exact Diagonalization and Density Matrix Renormalization Group
approaches for N \le 4.


title: On the logarithmic Schrodinger equation

abstract:
  In the framework of the nonsmooth critical point theory for lower
semi-continuous functionals, we propose a direct variational approach to
investigate the existence of infinitely many weak solutions for a class of
semi-linear elliptic equations with logarithmic nonlinearity arising in
physically relevant situations. Furthermore, we prove that there exists a
unique positive solution which is radially symmetric and nondegenerate.


title: Toward computability of trace distance discord

abstract:
  It is known that a reliable geometric quantifier of discord-like correlations
can be built by employing the so-called trace distance. This is used to measure
how far the state under investigation is from the closest "classical-quantum"
one. To date, the explicit calculation of this indicator for two qubits was
accomplished only for states such that the reduced density matrix of the
measured party is maximally mixed, a class that includes Bell-diagonal states.
Here, we first reduce the required optimization for a general two-qubit state
to the minimization of an explicit two-variable function. Using this framework,
we show next that the minimum can be analytically worked out in a number of
relevant cases including quantum-classical and X states. This provides an
explicit and compact expression for the trace distance discord of an arbitrary
state belonging to either of these important classes of density matrices.


title: Dual Fermion Condensates in Curved Space

abstract:
  In this paper we compute the effective action at finite temperature and
density for the dual fermion condensate in curved space with the fermions
described by an effective field theory with four-point interactions. The
approach we adopt refines a technique developed earlier to study chiral
symmetry breaking in curved space and it is generalized here to include the
U$(1)$-valued boundary conditions necessary to define the dual condensate. The
method we present is general, includes the coupling between the fermion
condensate and the Polyakov loop, and applies to any ultrastatic background
spacetime with a nonsingular base. It also allows one to include inhomogeneous
and anisotropic phases and therefore it is suitable to study situations where
the geometry is not homogeneous. We first illustrate a procedure, based on heat
kernels, useful to deal with situations where the dual and chiral condensates
(as well as any smooth background field eventually present) are slowly or
rapidly varying functions in space. Then we discuss a different approach based
on the density of states method and on the use of Tauberian theorems to handle
the case of arbitrary chemical potentials. As a trial application, we consider
the case of constant curvature spacetimes and show how to compute numerically
the dual fermion condensate in the case of both homogeneous and inhomogeneous
phases.


title: Theory of Cold Atoms: Basics of Quantum Statistics

abstract:
  The aim of this Tutorial is to present the basic mathematical techniques
required for an accurate description of cold trapped atoms, both Bose and
Fermi. The term {\it cold} implies that considered temperatures are low, such
that quantum theory is necessary, even if temperatures are finite. And the term
{\it atoms} means that the considered particles are structureless, being
defined by their masses and mutual interactions. Atoms are {\it trapped} in the
sense that they form a finite quantum system, though their number can be very
large allowing for the use of the methods of statistical mechanics. This
Tutorial is the first part of several tutorials, giving general mathematical
techniques for both types of particle statistics. The following tutorials will
be devoted separately to Bose atoms and Fermi atoms. The necessity of carefully
explaining basic techniques is important for avoiding numerous misconceptions
often propagating in literature.


title:
Momentum Fractions of Quarks and Gluons in a Self-similarity based model
  of Proton

abstract:
  In this paper, we use momentum sum rule to compute the fractions of momentum
carried by quarks and gluons in a self-similarity based model of proton.
Comparison of the results with the prediction of QCD asymptotics is also made.


title: Association schemoids and their categories

abstract:
  We propose the notion of association schemoids generalizing that of
association schemes from small categorical points of view. In particular, a
generalization of the Bose-Mesner algebra of an association scheme appears as a
subalgebra in the category algebra of the underlying category of a schemoid. In
this paper, the equivalence between the categories of grouopids and that of
thin association schemoids is established. Moreover linear extensions of
schemoids are considered. A general theory of the Baues-Wirsching cohomology
deduces a classification theorem for such extensions of a schemoid. We also
introduce two relevant categories of schemoids into which the categories of
schemes due to Hanaki and due to French are embedded, respectively.


title:
Combustion of a neutron star into a strange quark star: The neutrino
  signal

abstract:
  There are strong indications that the process of conversion of a neutron star
into a strange quark star proceeds as a strong deflagration implying that in a
few milliseconds almost the whole star is converted. Starting from the
three-dimensional hydrodynamic simulations of the combustion process which
provide the temperature profiles inside the newly born strange star, we
calculate for the first time the neutrino signal that is to be expected if such
a conversion process takes place. The neutrino emission is characterized by a
luminosity and a duration that is typical for the signal expected from
protoneutron stars and represents therefore a powerful source of neutrinos
which could be possibly directly detected in case of events occurring close to
our Galaxy. We discuss moreover possible connections between the birth of
strange stars and explosive phenomena such as supernovae and gamma-ray-bursts.


title:
Results of experimental investigations of cobalt beta decay rate
  variation

abstract:
  Results of long-term investigations of variation of cobalt beta decay rate
from 28.12.2010 till 08.02.2012 are presented. The scintillation spectrometer
with two LaBr3 detectors is used to register of gamma-quanta with energy 1.173
and 1.332 MeV accompanying cobalt beta decay. Counting rate of each detector
and their gamma-quanta coincidence are collected in successive time intervals
10 s. The statistical Kolmogorov-Smirnov method for data analysis is used.
Temperature influence on experimental results is also analyzed. Deviations of
beta decay counting rate from constant distribution during the days were
detected in those decades: from 11.03 to 21.03 with significance level a = 0.1;
from 22.04 to 02.05 with a=0.0125; from 24.06 to 04.07 with a=0.05; from 04.08
to 14.08 with a=0.05.


title:
Suris tetrons: possible spectroscopic evidence for four-particle optical
  excitations of the 2D electron gas

abstract:
  The excitations of a two-dimensional electron gas in quantum wells with
intermediate carrier density (~10^{11} cm^{-2}), i.e., between the
exciton-trion- and the Fermi-Sea range, are so far poorly understood. We report
on an approach to bridge this gap by a magneto-photoluminescence study of
modulation-doped (Cd,Mn)Te quantum well structures. Employing their enhanced
spin splitting, we analyzed the characteristic magnetic-field behavior of the
individual photoluminescence features. Based on these results and earlier
findings by other authors, we present a new approach for understanding the
optical transitions at intermediate densities in terms of four-particle
excitations, the Suris tetrons, which were up to now only predicted
theoretically. All characteristic photoluminescence features are attributed to
emission from these quasi-particles when attaining different final states.


title:
Positive Integer Solutions of the Pell Equation $x^{2}-dy^{2}=N,$ $%
  d\in \left\{k^{2}\pm 4,\text{}k^{2}\pm 1\right\} $ and $N\in \left\{\pm 1,\pm
  4\right\}

abstract:
  Let $\ k$ be a natural number and $d=k^{2}\pm 4$ or $k^{2}\pm 1$. In this
paper, by using continued fraction expansion of $\sqrt{d},$ we find fundamental
solution of the equations $x^{2}-dy^{2}=\pm 1$ and we get all positive integer
solutions of the equations $x^{2}-dy^{2}=\pm 1$ in terms of generalized
Fibonacci and Lucas sequences. Moreover, we find all positive integer solutions
of the equations $x^{2}-dy^{2}=\pm 4$ in terms of generalized Fibonacci and
Lucas sequences. Although some of the results are well known, we think our
method is elementary and different from the others.


title:
Hermitian Categories, Extension of Scalars and Systems of Sesquilinear
  Forms

abstract:
  We prove that the category of systems of sesquilinear forms over a given
hermitian category is equivalent to the category of unimodular 1-hermitian
forms over another hermitian category. The sesquilinear forms are not required
to be unimodular or defined on a reflexive object (i.e. the standard map from
the object to its double dual is not assumed to be bijective), and the forms in
the system can be defined with respect to different hermitian structures on the
given category. This extends a result obtained by E. Bayer-Fluckiger and D.
Moldovan.
  We use the equivalence to define a Witt ring of sesquilinear forms over a
hermitian category, and also to generalize various results (e.g.: Witt's
Cancelation Theorem, Springer's Theorem, the weak Hasse principle, finiteness
of genus) to systems of sesquilinear forms over hermitian categories.


title:
Reduced Gr\"obner Bases and Macaulay-Buchberger Basis Theorem over
  Noetherian Rings

abstract:
  In this paper, we extend the characterization of $\mathbb{Z}[x]/\ < f \ >$,
where $f \in \mathbb{Z}[x]$ to be a free $\mathbb{Z}$-module to multivariate
polynomial rings over any commutative Noetherian ring, $A$. The
characterization allows us to extend the Gr\"obner basis method of computing a
$\Bbbk$-vector space basis of residue class polynomial rings over a field
$\Bbbk$ (Macaulay-Buchberger Basis Theorem) to rings, i.e.
$A[x_1,\ldots,x_n]/\mathfrak{a}$, where $\mathfrak{a} \subseteq
A[x_1,\ldots,x_n]$ is an ideal. We give some insights into the characterization
for two special cases, when $A = \mathbb{Z}$ and $A =
\Bbbk[\theta_1,\ldots,\theta_m]$. As an application of this characterization,
we show that the concept of border bases can be extended to rings when the
corresponding residue class ring is a finitely generated, free $A$-module.


title:
Algebraic versus exponential decoherence in dissipative many-particle
  systems

abstract:
  The interplay between dissipation and internal interactions in quantum
many-body systems gives rise to a wealth of novel phenomena. Here we
investigate spin-1/2 chains with uniform local couplings to a Markovian
environment using the time-dependent density matrix renormalization group
(tDMRG). For the open XXZ model, we discover that the decoherence time diverges
in the thermodynamic limit. The coherence decay is then algebraic instead of
exponential. This is due to a vanishing gap in the spectrum of the
corresponding Liouville superoperator and can be explained on the basis of a
perturbative treatment. In contrast, decoherence in the open transverse-field
Ising model is found to be always exponential. In this case, the internal
interactions can both facilitate and impede the environment-induced
decoherence.


title: The heating history of Vesta and the onset of differentiation

abstract:
  In this work we study the link between the evolution of the internal
structure of Vesta and thermal heating due to 26Al and 60Fe and long-lived
radionuclides, taking into account the chemical differentiation of the body and
the affinity of 26Al with silicates. Differentiation takes place in all
scenarios in which Vesta completes its accretion in less than 1.4 Ma after the
injection of 26Al into the Solar Nebula. In all those scenarios where Vesta
completes its formation in less than 1 Ma from the injection of 26Al, the
degree of silicate melting reaches 100 vol. % throughout the whole asteroid. If
Vesta completed its formation between 1 and 1.4 Ma after 26Al injection, the
degree of silicate melting exceeds 50 vol. % over the whole asteroid but
reaches 100 vol. % only in the hottest, outermost part of the mantle in all
scenarios where the porosity is lower than 5 vol. %. If the formation of Vesta
occurred later than 1.5 Ma after the injection of 26Al, the degree of silicate
melting is always lower than 50 vol. % and is limited only to a small region of
the asteroid. The radiation at the surface dominates the evolution of the crust
which ranges in thickness from 8 to about 30 km after 5 Ma: a layer about 3-20
km thick is composed of primitive unmelted chondritic material while a layer of
about 5-10 km is eucritic.


title: Stability of binary on highly eccentric orbit

abstract:
  It is known, that possibility to capture on a satellite orbit is decreased
with primary orbital eccentricity increasing. It means, that satellites of
planet on eccentric orbit are less stable. We study problem by analytical and
numeric methods. A difference between case of infinitesimal mass satellite and
true binary system is shown. The dependence of orbital energy on external
eccentricity is derived for binary system. In result of our studying, we can
conclude, that extrasolar planets may have significantly smaller satellites,
than planets in our solar system. Moreover, dependence on eccentricity makes
restriction on giant planets migration in our Solar System. The application to
a flight dynamics and mission design is discussed.


title:
A space efficient flexible pivot selection approach to evaluate
  determinant and inverse of a matrix

abstract:
  This paper presents new approaches for finding the determinant and inverse of
a matrix. The choice of pivot selection is kept arbitrary and can be made
according to the users need. So the ill conditioned matrices can be handled
easily. The algorithms are more efficient as they save unnecessary data storage
by reducing the order of the matrix after each iteration in the computation of
determinant and incorporating dictionary notation (Chvatal, 1983) in the
computation of inverse matrix. These algorithms are highly class room oriented
and unlike the matrix inversion method (Khan, Shah, & Ahmad, 2010) the
presented algorithm does not need any kind of permutations or inverse
permutations.


title: Artificial Free Clone Of Simplex Method For Feasibility

abstract:
  This paper presents a method which is identical to simplex method phase 1,
but do not need any artificial variable (or artificial constraints). So, the
new method works in original variable space but visits the same sequence of
pivots as simplex method does. Recently, (Inayatullah, Khan, Imtiaz & Khan, New
artificial-free Phase 1 Simplex Method, 2009) claimed a similar method, here in
this paper we have presented a counter example which shows in some special
conditions of degeneracy their method may deviate from the simplex path.
  Because of its simplicity, the method presented in this paper is highly
classroom oriented. So, indeed there is no need to work with artificial
variables (or artificial constraints) in simplex method any more.


title: QCD results from ATLAS

abstract:
  The most recent QCD measurements performed in ATLAS are reviewed; the results
summarized here are based on data collected with the ATLAS detector during the
2010 and 2011 data taking in proton-proton collisions at center of mass energy
sqrt s = 7 TeV at the Large Hadron Collider, corresponding approximately to an
integrated luminosity of 36 pb^-1 and 4.6 fb^-1 respectively.


title: Strongly light subgraphs in the 1-planar graphs with minimum degree 7

abstract:
  A graph is {\em $1$-planar} if it can be drawn in the plane such that every
edge crosses at most one other edge. A connected graph $H$ is {\em strongly
light} in a family of graphs $\mathfrak{G}$, if there exists a constant
$\lambda$, such that every graph $G$ in $\mathfrak{G}$ contains a subgraph $K$
isomorphic to $H$ with $\deg_{G}(v) \leq \lambda$ for all $v \in V(K)$. In this
paper, we present some strongly light subgraphs in the family of $1$-planar
graphs with minimum degree~$7$.


title: The Power and Limitations of Static Binary Search Trees with Lazy Finger

abstract:
  A static binary search tree where every search starts from where the previous
one ends (lazy finger) is considered. Such a search method is more powerful
than that of the classic optimal static trees, where every search starts from
the root (root finger), and less powerful than when rotations are
allowed---where finding the best rotation based tree is the topic of the
dynamic optimality conjecture of Sleator and Tarjan. The runtime of the classic
root-finger tree can be expressed in terms of the entropy of the distribution
of the searches, but we show that this is not the case for the optimal lazy
finger tree. A non-entropy based asymptotically-tight expression for the
runtime of the optimal lazy finger trees is derived, and a dynamic
programming-based method is presented to compute the optimal tree.


title:
Automated Synthesis of Controllers for Search and Rescue from Temporal
  Logic Specifications

abstract:
  In this thesis, the synthesis of correct-by-construction controllers for
robots assisting in Search and Rescue (SAR) is considered. In recent years, the
development of robots assisting in disaster mitigation in urban environments
has been actively encouraged, since robots can be deployed in dangerous and
hazardous areas where human SAR operations would not be possible.
  In order to meet the reliability requirements in SAR, the specifications of
the robots are stated in Linear Temporal Logic and synthesized into finite
state machines that can be executed as controllers. The resulting controllers
are purely discrete and maintain an ongoing interaction with their environment
by changing their internal state according to the inputs they receive from
sensors or other robots.
  Since SAR robots have to cooperate in order to complete the required tasks,
the synthesis of controllers that together achieve a common goal is considered.
This distributed synthesis problem is provably undecidable, hence it cannot be
solved in full generality, but a set of design principles is introduced in
order to develop specialized synthesizable specifications. In particular,
communication and cooperation are resolved by introducing a verified
standardized communication protocol and preempting negotiations between robots.
  The robots move on a graph on which we consider the search for stationary and
moving targets. Searching for moving targets is cast into a game of cops and
robbers, and specifications implementing a winning strategy are developed so
that the number of robots required is minimized.
  The viability of the methods is demonstrated by synthesizing controllers for
robots performing search and rescue for stationary targets and searching for
moving targets. It is shown that the controllers are guaranteed to achieve the
common goal of finding and rescuing the targets.


title: An implementation of the relational k-means algorithm

abstract:
  A C# implementation of a generalized k-means variant called relational
k-means is described here. Relational k-means is a generalization of the
well-known k-means clustering method which works for non-Euclidean scenarios as
well. The input is an arbitrary distance matrix, as opposed to the traditional
k-means method, where the clustered objects need to be identified with vectors.


title:
Identification of coherent lattice modulations coupled to charge and
  orbital order in a manganite

abstract:
  We apply grazing-incidence femtosecond x-ray diffraction to investigate the
details of the atomic motion connected with a displacively excited coherent
optical phonon. We concentrate on the low frequency phonon associated with the
charge and orbital order in the mixed valence manganite
La0.25Pr0.375Ca0.375MnO3 for T < 210 K. We measure the response of three
superlattice reflections that feature different sensitivities to the motion of
the unit cell constituents. The results support the assignment to a
translational mode of the Mn4+ atoms together with the oxygen atoms connecting
adjacent Mn4+ sites.


title: Fractional and integer matchings in uniform hypergraphs

abstract:
  Our main result improves bounds of Markstrom and Rucinski on the minimum
d-degree which forces a perfect matching in a k-uniform hypergraph on n
vertices. We also extend bounds of Bollobas, Daykin and Erdos by asymptotically
determining the minimum vertex degree which forces a matching of size t <
n/2(k-1) in a k-uniform hypergraph on n vertices. Further asymptotically tight
results on d-degrees which force large matchings are also obtained. Our
approach is to prove fractional versions of the above results and then
translate these into integer versions.


title: Non-Markovian effects in waveguide-mediated entanglement

abstract:
  We study the generation and evolution of entanglement between two qubits
coupled through one-dimensional waveguide modes. By using a complete quantum
electrodynamical formalism we go beyond the Markovian approximation. The
diagonalization of the hamiltonian is carried out, and a set of quasi-localized
eigenstates is found. We show that when the qubit-waveguide coupling is
increased, the Markov approximation is not anymore valid, and the generation of
entanglement is worsened.


title: The XXZ Heisenberg model on random surfaces

abstract:
  We consider integrable models, or in general any model defined by an
$R$-matrix, on random surfaces, which are discretized using random Manhattan
lattices. The set of random Manhattan lattices is defined as the set dual to
the lattice random surfaces embedded on a regular d-dimensional lattice. They
can also be associated with the random graphs of multiparticle scattering
nodes. As an example we formulate a random matrix model where the partition
function reproduces the annealed average of the XXZ Heisenberg model over all
random Manhattan lattices. A technique is presented which reduces the random
matrix integration in partition function to an integration over their
eigenvalues.


title:
Kinklike structures in scalar field theories: from one-field to
  two-field models

abstract:
  In this paper we study the possibility of constructing two-field models from
one-field models. The idea is to start with a given one-field model and use the
deformation procedure to generate another one-field model, and then couple the
two one-field models nontrivially, to get to a two-field model, together with
some explicit topological solutions. We show with several distinct examples
that the procedure works nicely and can be used generically.


title: Recent developments concerning generic spacelike singularities

abstract:
  This is a review of recent progress concerning generic spacelike
singularities in general relativity. For brevity the main focus is on
singularities in vacuum spacetimes, although the connection with, and the role
of, matter for generic singularity formation is also commented on. The paper
describes recent developments in two areas and show how these are connected
within the context of the conformally Hubble-normalized state space approach.
The first area is oscillatory singularities in spatially homogeneous cosmology
and the connection between asymptotic behaviour and heteroclinic chains. The
second area concerns oscillatory singularities in inhomogeneous models,
especially spike chains and recurring spikes. The review also outlines some
underlying reasons for why the structures that are the foundation for generic
oscillatory behaviour exists at all, which entails discussing how underlying
physical principles and applications of solution generating techniques yield
hierarchical structures and connections between them. Finally, it is pointed
out that recent progress concerning generic singularities motivates some
speculations that suggest that a paradigm shift concerning their physical role,
and what mathematical issues to address, might be in order.


title: Approximating Semi-Matchings in Streaming and in Two-Party Communication

abstract:
  We study the communication complexity and streaming complexity of
approximating unweighted semi-matchings. A semi-matching in a bipartite graph G
= (A, B, E), with n = |A|, is a subset of edges S that matches all A vertices
to B vertices with the goal usually being to do this as fairly as possible.
While the term 'semi-matching' was coined in 2003 by Harvey et al. [WADS 2003],
the problem had already previously been studied in the scheduling literature
under different names.
  We present a deterministic one-pass streaming algorithm that for any 0 <=
\epsilon <= 1 uses space O(n^{1+\epsilon}) and computes an
O(n^{(1-\epsilon)/2})-approximation to the semi-matching problem. Furthermore,
with O(log n) passes it is possible to compute an O(log n)-approximation with
space O(n).
  In the one-way two-party communication setting, we show that for every
\epsilon > 0, deterministic communication protocols for computing an
O(n^{1/((1+\epsilon)c + 1)})-approximation require a message of size more than
cn bits. We present two deterministic protocols communicating n and 2n edges
that compute an O(sqrt(n)) and an O(n^{1/3})-approximation respectively.
  Finally, we improve on results of Harvey et al. [Journal of Algorithms 2006]
and prove new links between semi-matchings and matchings. While it was known
that an optimal semi-matching contains a maximum matching, we show that there
is a hierarchical decomposition of an optimal semi-matching into maximum
matchings. A similar result holds for semi-matchings that do not admit
length-two degree-minimizing paths.


title:
Does a hadron-quark phase transition in dense matter preclude the
  existence of massive neutron stars ?

abstract:
  We study the impact of a hadron-quark phase transition on the maximum
neutron-star mass. The hadronic part of the equation of state relies on the
most up-to-date Skyrme nuclear energy density functionals, fitted to
essentially all experimental nuclear mass data and constrained to reproduce the
properties of infinite nuclear matter as obtained from microscopic calculations
using realistic forces. We show that the softening of the dense matter equation
of state due to the phase transition is not necessarily incompatible with the
existence of massive neutron stars like PSR J1614-2230.


title:
Physics-compatible discretization techniques on single and dual grids,
  with application to the Poisson equation of volume forms

abstract:
  This paper introduces the basic concepts for physics-compatible
discretization techniques. The paper gives a clear distinction between vectors
and forms. Based on the difference between forms and pseudo-forms and the
$\star$-operator which switches between the two, a dual grid description and a
single grid description are presented. The dual grid method resembles a
staggered finite volume method, whereas the single grid approach shows a strong
resemblance with a finite element method. Both approaches are compared for the
Poisson equation for volume forms.


title: Electrowetting of a soap bubble

abstract:
  A proof-of-concept demonstration of the electrowetting-on-dielectric of a
sessile soap bubble is reported here. The bubbles are generated using a
commercial soap bubble mixture - the surfaces are composed of highly doped,
commercial silicon wafers covered with nanometre thick films of Teflon.
Voltages less than 40V are sufficient to observe the modification of the bubble
shape and the apparent bubble contact angle. Such observations open the way to
inter alia the possibility of bubble-transport, as opposed to
droplet-transport, in fluidic microsystems (e.g. laboratory-on-a-chip) - the
potential gains in terms of volume, speed and surface/volume ratio are
non-negligible.


title: Graham's Number is Less Than 2^^^6

abstract:
  In [5] Graham and Rothschild consider a geometric Ramsey problem: finding the
least n such that if all edges of the complete graph on the points {+1,-1}^n
are 2-colored, there exist 4 coplanar points such that the 6 edges between them
are monochromatic. They give an explicit upper bound: F(F(F(F(F(F(F(12))))))),
where F(m) = 2^^(m)^^3, an extremely fast-growing function. By reducing the
problem to a variant of the Hales-Jewett problem, we find an upper bound which
is between F(4) and F(5).


title: Edge states protected by chiral symmetry in disordered photonic graphene

abstract:
  We experimentally investigate the impact of uncorrelated composite and
structural disorder in photonic graphene. We find that in case of structural
disorder not only chiral symmetry, but also the vanishing of the density of
states at zero energy is preserved. This is in contrast to composite disorder,
where chiral symmetry as well as the vanishing of the density of states are
destroyed. Our observations are experimentally proven by exciting edge states
at the bearded edge in disordered photonic graphene.


title:
Automatic reconstruction of fault networks from seismicity catalogs
  including location uncertainty

abstract:
  We introduce the Anisotropic Clustering of Location Uncertainty Distributions
(ACLUD) method to reconstruct active fault networks on the basis of both
earthquake locations and their estimated individual uncertainties. After a
massive search through the large solution space of possible reconstructed fault
networks, we apply six different validation procedures in order to select the
corresponding best fault network. Two of the validation steps (cross-validation
and Bayesian Information Criterion (BIC) process the fit residuals, while the
four others look for solutions that provide the best agreement with
independently observed focal mechanisms. Tests on synthetic catalogs allow us
to qualify the performance of the fitting method and of the various validation
procedures. The ACLUD method is able to provide solutions that are close to the
expected ones, especially for the BIC and focal mechanismbased techniques. The
clustering method complemented by the validation step based on focal mechanisms
provides good solutions even in the presence of a significant spatial
background seismicity rate. Our new fault reconstruction method is then applied
to the Landers area in Southern California and compared with previous
clustering methods. The results stress the importance of taking into account
undersampled sub-fault structures as well as of the spatially inhomogeneous
location uncertainties.


title: On the regularity of the conditional distribution of the sample mean

abstract:
  We show that the hypothesis of regularity of the conditional distribution of
the empiric average of a finite sample of IID random variables, given all the
sample "fluctuations", which appeared in our earlier manuscript |1] in the
context of the eigenvalue concentration analysis for multi-particle random
operators, is satisfied for a class of probability distributions with
piecewise-constant or sufficiently smooth probability density. It extends the
well-known property of Gausssian IID samples.


title:
Tracing molecular dynamics at the femto-/atto-second boundary through
  extreme-ultraviolet pump-probe spectroscopy

abstract:
  Coherent light pulses of few to hundreds of femtoseconds (fs) duration have
prolifically served the field of ultrafast phenomena. While fs pulses address
mainly dynamics of nuclear motion in molecules or lattices in the gas, liquid
or condensed matter phase, the advent of attosecond pulses has in recent years
provided direct experimental access to ultrafast electron dynamics. However,
there are processes involving nuclear motion in molecules and in particular
coupled electronic and nuclear motion that possess few fs or even sub-fs
dynamics. In the present work we have succeeded in addressing simultaneously
vibrational and electronic dynamics in molecular Hydrogen. Utilizing a
broadband extreme-ultraviolet (XUV) continuum the entire, Frank-Condon allowed
spectrum of H2 is coherently excited. Vibrational, electronic and ionization
1fs scale dynamics are subsequently tracked by means of XUV-pump-XUV-probe
measurements. These reflect the intrinsic molecular behavior as the XUV probe
pulse hardly distorts the molecular potential.


title: A Note on the Field-Theoretical Description of Superfluids

abstract:
  Recently, a Lagrangian description of superfluids attracted some interest
from the fluid/gravity-correspondence viewpoint. In this respect, the work of
Dubovksy et al. has proposed a new field theoretical description of fluids,
which has several interesting aspects. On another side, we have provided in
arXiv:1304.2206 a supersymmetric extension of the original works. In the
analysis of the Lagrangian structures a new invariant appeared which, although
related to known invariants, provides, in our opinion, a better parametrisation
of the fluid dynamics in order to describe the fluid/superfluid phases.


title: Differentiability of Lipschitz Functions in Lebesgue Null Sets

abstract:
  We show that if n>1 then there exists a Lebesgue null set in R^n containing a
point of differentiability of each Lipschitz function mapping from R^n to
R^(n-1); in combination with the work of others, this completes the
investigation of when the classical Rademacher theorem admits a converse.
Avoidance of sigma-porous sets, arising as irregular points of Lipschitz
functions, plays a key role in the proof.


title:
On Vinogradov's mean value theorem: strongly diagonal behaviour via
  efficient congruencing

abstract:
  We enhance the efficient congruencing method for estimating Vinogradov's
integral for moments of order $2s$, with $1\le s\le k^2-1$. In this way, we
prove the main conjecture for such even moments when $1\le s\le
\tfrac{1}{4}(k+1)^2$, showing that the moments exhibit strongly diagonal
behaviour in this range. There are improvements also for larger values of $s$,
these finding application to the asymptotic formula in Waring's problem.


title: Jordanian deformation of the open sl(2) Gaudin model

abstract:
  We derive the deformed sl(2) Gaudin model with integrable boundaries.
Starting from the Jordanian deformation of the SL(2)-invariant Yang R-matrix
and generic solutions of the associated reflection equation and the dual
reflection equation, the corresponding inhomogeneous spin-1/2 XXX chain is
obtained. The quasi-classical expansion of the transfer matrix yields the
deformed sl(2) Gaudin Hamiltonians with boundary terms.


title: Iterative path integral summation for nonequilibrium quantum transport

abstract:
  We have developed a numerically exact approach to compute real-time path
integral expressions for quantum transport problems out of equilibrium. The
scheme is based on a deterministic iterative summation of the path integral
(ISPI) for the generating function of nonequilibrium observables of interest,
e.g., the charge current or dynamical quantities of the central part.
Self-energies due to the leads, being nonlocal in time, are fully taken into
account within a finite memory time, thereby including non-Markovian effects.
Numerical results are extra-polated first to vanishing (Trotter) time
discretization and, second, to infinite memory time...


title: Contextual Query Using Bell Tests

abstract:
  Tests are essential in Information Retrieval and Data Mining in order to
evaluate the effectiveness of a query. An automatic measure tool intended to
exhibit the meaning of words in context has been developed and linked with
Quantum Theory, particularly entanglement. "Quantum like" experiments were
undertaken on semantic space based on the Hyperspace Analogue Language (HAL)
method. A quantum HAL model was implemented using state vectors issued from the
HAL matrix and query observables, testing a wide range of windows sizes. The
Bell parameter S, associating measures on two words in a document, was derived
showing peaks for specific window sizes. The peaks show maximum quantum
violation of the Bell inequalities and are document dependent. This new
correlation measure inspired by Quantum Theory could be promising for measuring
query relevance.


title:
Mean-field optical bistability of two-level atoms in structured
  reservoirs

abstract:
  We consider N driven two-level atoms interacting with a structured reservoir.
By dressing the collective operators within a semiclassical approach, we derive
a master equation and a mean-field single particle effective Hamiltonian. This
Hamiltonian describes the optical bistability phenomenon occurring in the
relation between an input electromagnetic field and the effective output
generated by the N atoms. The dissipative part of the master equation and the
effective single-particle Hamiltonian contain new terms due the reservoir
structure of modes. In plotting the output field amplitude and phase, for a
structured reservoir, as function of the input amplitude, one verifies the
bistable behavior in both. We illustrate our results for two structured
reservoirs: one having a Lorentzian shape for the distribution of modes, and
the second is modeled as a photonic band-gap structure.


title:
Radiation Spectrum of a Magnetized Supercritical Accretion Disc with
  Thermal Conduction

abstract:
  We examine the effect of thermal conduction on the observational properties
of a super critical hot magnetized flow. We obtained self-similar solution of a
magnetized disc when the thermal conduction plays an important role. Follow of
our first paper (Ghasemnezhad et al. 2012 (hereafter GKA12)) we have extended
our solution on the observational appearance of the disc to show how physical
condition such as thermal conduction, viscosity, and advection will change the
observed luminosity of the disc, Continuous spectra and surface temperature of
such discs was plotted. We apply the present model to black-hole X-ray binary
LMC X-3 and narrow-line seyfert 1 galaxies, which are supposed to be under
critical accretion rate. Our results show clearly that the surface temperature
is strongly depends on the thermal conduction, the magnetic field and advection
parameter. However we see that thermal conduction acts to oppose the
temperature gradient as we expect and observed luminosity of the disc will
reduce when thermal conduction is high. We have shown that in this model the
spectra of critical accretion flows strongly depends on the inclination angle.


title:
Massive stars at low metallicity: Evolution and surface abundances of O
  dwarfs in the SMC

abstract:
  We study the evolution, rotation, and surface abundances of O-type dwarfs in
the Small Magellanic Cloud. We analyzed the UV and optical spectra of
twenty-three objects and derived photospheric and wind properties. The observed
binary fraction of the sample is ~ 26%, which is compatible with more
systematic studies, if one considers that the actual binary fraction is
potentially larger owing to low-luminosity companions and that the sample
excluded obvious spectroscopic binaries. The location of the fastest rotators
in the H-R diagram indicates that these could be several Myr old. The offset in
the position of these fast rotators compared with the other stars confirms the
predictions of evolutionary models that fast-rotating stars tend to evolve more
vertically in the H-R diagram. Only one star of luminosity-class Vz, expected
to best characterize extreme youth, is located on the ZAMS, the other two stars
are more evolved. The distribution of nitrogen abundance of O and B stars
suggests that the mechanisms responsible for the chemical enrichment of slowly
rotating massive stars depends only weakly on the star's mass. We confirm that
the group of slowly rotating N-rich stars is not reproduced by the evolutionary
tracks. Our results call for stronger mixing in the models to explain the range
of observed N abundances. All stars have an N/C ratio as a function of stellar
luminosity that matches the predictions of the stellar evolution models well.
More massive stars have a higher N/C ratio than the less massive stars. Faster
rotators show on average a higher N/C ratio than slower rotators. The N/O
versus N/C ratios agree qualitatively well with those of stellar evolution
models. The only discrepant behavior is observed for the youngest two stars of
the sample, which both show very strong signs of mixing, which is unexpected
for their evolutionary status.


title: Non-asymptotic detection of two-component mixtures with unknown means

abstract:
  This work is concerned with the detection of a mixture distribution from a
$\mathbb{R}$-valued sample. Given a sample $X_1,\dots,X_n$ and an even density
$\phi$, our aim is to detect whether the sample distribution is
$\phi(\cdot-\mu)$ for some unknown mean $\mu$, or is defined as a two-component
mixture based on translations of $\phi$. We propose a procedure which is based
on several spacings of the order statistics, which provides a level-$\alpha$
test for all $n$. Our test is therefore a multiple testing procedure and we
prove from a theoretical and practical point of view that it automatically
adapts to the proportion of the mixture and to the difference of the means of
the two components of the mixture under the alternative. From a theoretical
point of view, we prove the optimality of the power of our procedure in various
situations. A simulation study shows the good performances of our test compared
with several classical procedures.


title:
Controlling the Depth, Size, and Number of Subtrees for Two-variable
  Logic on Trees

abstract:
  Verification of properties of first order logic with two variables FO2 has
been investigated in a number of contexts. Over arbitrary structures it is
known to be decidable with NEXPTIME complexity, with finitely satisfiable
formulas having exponential-sized models. Over word structures, where FO2 is
known to have the same expressiveness as unary temporal logic, the same
properties hold. Over finite labelled ordered trees FO2 is also of interest: it
is known to have the same expressiveness as navigational XPath, a common query
language for XML documents. Prior work on XPath and FO2 gives a 2EXPTIME bound
for satisfiability of FO2. In this work we give the first in-depth look at the
complexity of FO2 on trees, and on the size and depth of models. We show that
the doubly-exponential bound is not tight, and neither do the
NEXPTIME-completeness results from the word case carry over: the exact
complexity varies depending on the vocabulary used, the presence or absence of
a schema, and the encoding used for labels. Our results depend on an analysis
of subformula types in models of FO2 formulas, including techniques for
controlling the number of distinct subtrees, the depth, and the size of a
witness to finite satisfiability for FO2 sentences over trees.


title: Mimetic Spectral Element advection

abstract:
  We present a discretization of the linear advection of differential forms on
bounded domains. The framework previously established is extended to
incorporate the Lie derivative, $\mathcal L$, by means of Cartan's homotopy
formula. The method is based on a physics-compatible discretization with
spectral accuracy . It will be shown that the derived scheme has spectral
convergence with local mass conservation. Artificial dispersion depends on the
order of time integration.


title:
NGC 2579 and the carbon and oxygen abundance gradients beyond the solar
  circle

abstract:
  We present deep echelle spectrophotometry of the Galactic HII region NGC
2579. The data have been taken with the Very Large Telescope Ultraviolet-Visual
Echelle Spectrograph in the 3550--10400 \AA\ range. This object, which has been
largely neglected, shows however a rather high surface brightness, a high
ionization degree and is located at a galactocentric distance of 12.4 $\pm$ 0.7
kpc. Therefore, NGC 2579 is an excellent probe for studying the behaviour of
the gas phase radial abundance gradients in the outer disc of the Milky Way. We
derive the physical conditions of the nebula using several emission
line-intensity ratios as well as the abundances of several ionic species from
the intensity of collisionally excited lines. We also determine the ionic
abundances of C$^{2+}$, O$^+$ and O$^{2+}$ -- and therefore the total O
abundance -- from faint pure recombination lines. The results for NGC 2579
permit to extend our previous determinations of the C, O and C/O gas phase
radial gradients of the inner Galactic disc (Esteban etal. 2005) to larger
galactocentric distances. We find that the chemical composition of NGC 2579 is
consistent with flatten gradients at its galactocentric distance. In addition,
we have built a tailored chemical evolution model that reproduces the observed
radial abundance gradients of O, C and N and other observational constraints.
We find that a levelling out of the star formation efficiency about and beyond
the isophotal radius can explain the flattening of chemical gradients observed
in the outer Galactic disc.


title: Studies on some exponential-screened Coulomb potentials

abstract:
  The generalized pseudospectral method is employed to study the bound-state
spectra of some of the exponentially screened Coulomb potentials, \emph{viz.},
the exponential cosine screened Coulomb (ECSC) and general exponential screened
Coulomb (GESC) potential, with special emphasis on \emph{higher} states and
\emph{stronger} interaction. Eigenvalues accurate up to eleven significant
figures are obtained through a non-uniform optimal spatial discretization of
the radial Schr\"odinger equation. All the 55 eigenstates of ECSC potential
with $n \le 10$ and 36 eigenstates of GESC potential with $n \le 8$ are
considered for arbitrary values of the screening parameter, covering a wide
range of interaction. Excited states as high as up to $n=18$ have been computed
with high accuracy for the first time. Excellent agreement with the literature
data has been observed in all cases. All the GESC eigenstates are calculated
with much greater accuracy than the existing methods available in literature.
Many $l \ne 0$ states of this potential are reported here. In both cases, a
detailed variation of energies with respect to the parameters in potential is
monitored.


title: Second order Boltzmann equation : gauge dependence and gauge invariance

abstract:
  In the context of cosmological perturbation theory, we derive the second
order Boltzmann equation describing the evolution of the distribution function
of radiation without a specific gauge choice. The essential steps in deriving
the Boltzmann equation are revisited and extended given this more general
framework: i) the polarisation of light is incorporated in this formalism by
using a tensor-valued distribution function; ii) the importance of a choice of
the tetrad field to define the local inertial frame in the description of the
distribution function is emphasized; iii) we perform a separation between
temperature and spectral distortion, both for the intensity and for
polarisation for the first time; iv) the gauge dependence of all perturbed
quantities that enter the Boltzmann equation is derived, and this enables us to
check the correctness of the perturbed Boltzmann equation by explicitly showing
its gauge-invariance for both intensity and polarization. We finally discuss
several implications of the gauge dependence for the observed temperature.


title: Resummation of non-global logarithms at finite $N_c$

abstract:
  In the context of inter-jet energy flow, we present the first quantitative
result of the resummation of non-global logarithms at finite N_c. This is
achieved by refining Weigert's approach in which the problem is reduced to the
simulation of associated Langevin dynamics in the space of Wilson lines. We
find that, in e+e- annihilation, the exact result is rather close to the result
previously obtained in the large-N_c mean field approximation. However, we
observe enormous event-by-event fluctuations in the Langevin process which may
have significant consequences in hadron collisions.


title: Evidence for B_s^0 -> Lambda_c^+ Lambda-bar pi^-

abstract:
  Using 121.4 fb^{-1} of data collected with the Belle detector at the Y(5S)
resonance at the KEKB asymmetric-energy e^+e^- collider, we report evidence for
the B_s^0 -> Lambda_c^+ Lambda-bar pi^- decay mode with a measured branching
fraction (3.6 +- 1.1[stat.] {+0.3 -0.5}[syst.] +- 0.9[Lambda_c^+] +-
0.7[N_{Bs}]) * 10^{-4} and a significance of 4.4 standard deviations. This is
the first evidence for a baryonic B_s^0 decay.


title: A relation between the dark mass of elliptical galaxies and their shape

abstract:
  We have studied a large number of elliptical galaxies and found a correlation
between their dark matter content and the ellipticity of their visible shape.
The galaxies were strictly selected so that only typical medium-size elliptical
galaxies were considered. Galaxies with unusual characteristics were rejected
to minimize point-to-point data scatter and avoid systematic biases. Data from
six different techniques of extracting the galactic dark matter content were
used to avoid methodological biases. A thorough investigation of the
interrelation between attributes of elliptical galaxies was carried out to
assess whether the correlation originates from an observational bias, but no
such origin could be identified. At face value, the correlation found implies
that at equal luminosities, rounder medium-size elliptical galaxies appear to
contain less dark matter than flatter elliptical galaxies, e.g. the rounder
galaxies are on average four times less massive than the flatter ones. This is
puzzling in the context of the conventional model of cosmological structure
formation.


title: Digit Recognition in Handwritten Weather Records

abstract:
  This paper addresses the automatic recognition of handwritten temperature
values in weather records. The localization of table cells is based on line
detection using projection profiles. Further, a stroke-preserving line removal
method which is based on gradient images is proposed. The presented digit
recognition utilizes features which are extracted using a set of filters and a
Support Vector Machine classifier. It was evaluated on the MNIST and the USPS
dataset and our own database with about 17,000 RGB digit images. An accuracy of
99.36% per digit is achieved for the entire system using a set of 84 weather
records.


title:
Towards a double-scaling limit for tensor models: probing sub-dominant
  orders

abstract:
  The definition of a double-scaling limit represents an important goal in the
development of tensor models. We take the first steps towards this goal by
extracting and analysing the next-to-leading order contributions, in the 1/N
expansion, for the IID tensor models. We show that the radius of convergence of
the NLO series coincides with that of the leading order melonic sector.
Meanwhile, the value of the susceptibility exponent at NLO is 3/2, signaling a
departure from the leading order behaviour. Both pieces of information provide
clues for a non-trivial double-scaling limit, for which we put forward some
precise conjecture.


title: Quantum correlations in a noisy neutron interferometer

abstract:
  We investigate quantum coherences in the presence of noise by entangling the
spin and path degrees of freedom of the output neutron beam from a noisy
three-blade perfect crystal neutron interferometer. We find that in the
presence of dephasing noise on the path degree of freedom the entanglement of
the output state reduces to zero, however the quantum discord remains non-zero
for all noise values. Hence even in the presence of strong phase noise
non-classical correlations persist between the spin and path of the neutron
beam. This indicates that measurements performed on the spin of the neutron
beam will induce a disturbance on the path state. We calculate the effect of
the spin measurement by observing the changes in the observed contrast of the
interferometer for an output beam post-selected on a given spin state. In doing
so we demonstrate that these measurements allow us to implement a quantum
eraser, and a which-way measurement of the path taken by the neutron through
the interferometer. While strong phase noise removes the quantum eraser, the
spin-filtered which-way measurement is robust to phase noise. We experimentally
demonstrate this disturbance by comparing the contrasts of the output beam with
and without spin measurements of three neutron interferometers with varying
noise strengths. This demonstrates that even in the presence of noise that
suppresses path coherence and spin-path entanglement, a neutron interferometer
still exhibits uniquely quantum behaviour.


title:
Strong gravity Lense-Thirring Precession in Kerr and Kerr-Taub-NUT
  spacetimes

abstract:
  An exact expression derived in the literature for the rate of dragging of
inertial frames (Lense-Thirring (LT) precession) in a general stationary
spacetime, is reviewed. The exact LT precession frequencies for Kerr,
Kerr-Taub-NUT and Taub-NUT spacetimes are explicitly derived. Remarkably, in
the case of the zero angular momentum Taub-NUT spacetime, the frame-dragging
effect is shown {\it not} to vanish, when considered for spinning test
gyroscopes. The result becomes sharper for the case of vanishing ADM mass of
that spacetime. We clarify how our results are consistent with claims in the
recent literature of null orbital plane precession for NUT spacetimes.


title: Detecting squarefree numbers

abstract:
  We present an algorithm, based on the explicit formula for $L$-functions and
conditional on GRH, for proving that a given integer is squarefree with little
or no knowledge of its factorization. We analyze the algorithm both
theoretically and practically, and use it to prove that several RSA challenge
numbers are not squarefull.


title:
Planck constraints on Higgs modulated reheating of renormalization group
  improved inflation

abstract:
  Within the framework of RG improved inflationary cosmology motivated by
asymptotically safe gravity, we study the dynamics of a scalar field which can
be interpreted as the Higgs field. The background trajectories of this model
can provide sufficient inflationary e-folds and a graceful exit to a radiation
dominated phase. We study the possibility of generating primordial curvature
perturbations through the Standard Model Higgs boson. This can be achieved
under finely tuned parameter choices by making use of the modulated reheating
mechanism. The primordial non-gaussianity is expected to be sizable in this
model. Though tightly constrained by the newly released Planck CMB data, this
model provides a potentially interesting connection between collider and early
universe physics.


title: Superstripes : superconductivity in complex granular striped matter

abstract:
  The role of phase separation and superstripes in high temperature
superconductors and related materials has been discussed at the meeting in
Erice, Italy, July 11 July 17, 2012. The focus was on the point where we are
after 25 years of research on the key role of complex structural, electronic,
and magnetic matter in the mechanism of high temperature superconductivity.


title:
New limits on variation of the fine-structure constant using atomic
  dysprosium

abstract:
  We report on the spectroscopy of radio-frequency transitions between
nearly-degenerate, opposite-parity excited states in atomic dysprosium (Dy).
Theoretical calculations predict that these states are very sensitive to
variation of the fine-structure constant, $\alpha$, owing to large relativistic
corrections of opposite sign for the opposite-parity levels. The near
degeneracy reduces the relative precision necessary to place constraints on
variation of $\alpha$ competitive with results obtained from the best atomic
clocks in the world. Additionally, the existence of several abundant isotopes
of Dy allows isotopic comparisons that suppress common-mode systematic errors.
The frequencies of the 754-MHz transition in $^{164}$Dy and 235-MHz transition
in $^{162}$Dy were measured over the span of two years. Linear variation of
$\alpha$ is found to be $\dot{\alpha}/\alpha = (-5.8\pm6.9)\times10^{-17}$
yr$^{-1}$, consistent with zero. The same data are used to constrain the
dimensionless parameter $k_\alpha$, characterizing a possible coupling of
$\alpha$ to a changing gravitational potential. We find that $k_\alpha =
(-5.5\pm5.2)\times10^{-7}$, essentially consistent with zero and the best
constraint to date.


title:
Fixed Points for Banach and Kannan Contractions in Modular Spaces with a
  Graph

abstract:
  In this paper, we discuss the existence and uniqueness of fixed points for
Banach and Kannan $\widetilde G$-$\rho$-contractions defined on modular spaces
endowed with a graph without using the $\Delta_2$-condition or the Fatou
property.


title:
Alignment dependent enhancement of the photo-electron cutoff for
  multi-photon ionization of molecules

abstract:
  The multiphoton ionization rate of molecules depends on the alignment of the
molecular axis with respect to the ionizing laser polarization. By studying
molecular frame photo-electron angular distributions from N$_2$, O$_2$ and
benzene, we illustrate how the angle-dependent ionization rate affects the
photo-electron cutoff energy. We find alignment can enhance the high energy
cutoff of the photo-electron spectrum when probing along a nodal plane or when
ionization is otherwise suppressed. This is supported by calculations using a
tunneling model with a single ion state.


title: Two Combinatorial Geometric Problems Involving Modular Hyperbolas

abstract:
  We give a lower bound for the number of ordinary lines spanned by a modular
hyperbola when the modulus is a prime power. We also give a partial answer to a
question of Shparlinski.


title:
Solving the Conformal Constraints for Scalar Operators in Momentum Space
  and the Evaluation of Feynman's Master Integrals

abstract:
  We investigate the structure of the constraints on three-point correlation
functions emerging when conformal invariance is imposed in momentum space and
in arbitrary space-time dimensions, presenting a derivation of their solutions
for arbitrary scalar operators. We show that the differential equations
generated by the requirement of symmetry under special conformal
transformations coincide with those satisfied by generalized hypergeometric
functions (Appell's functions). Combined with the position space expression of
this correlator, whose Fourier transform is given by a family of generalized
Feynman (master) integrals, the method allows to derive the expression of such
integrals in a completely independent way, bypassing the use of Mellin-Barnes
techniques, which have been used in the past. The application of the special
conformal constraints generates a new recursion relation for this family of
integrals.


title: A bibliometric index based on the complete list of cited publications

abstract:
  We propose a new index, the $j$-index, which is defined for an author as the
sum of the square roots of the numbers of citations to each of the author's
publications. The idea behind the $j$-index it to remedy a drawback of the
$h$-index $-$ that the $h$-index does not take into account the full citation
record of a researcher. The square root function is motivated by our desire to
avoid the possible bias that may occur with a simple sum when an author has
several very highly cited papers. We compare the $j$-index to the $h$-index,
the $g$-index and the total citation count for three subject areas using
several association measures.
  Our results indicate that that the association between the $j$-index and the
other indices varies according to the subject area. One explanation of this
variation may be due to the proportion of citations to publications of the
researcher that are in the $h$-core. The $j$-index is {\em not} an $h$-index
variant, and as such is intended to complement rather than necessarily replace
the $h$-index and other bibliometric indicators, thus providing a more complete
picture of a researcher's achievements.


title: Pure connection gravity at one loop: Instanton background

abstract:
  In the "pure connection" formulation General Relativity becomes a particular
diffeomorphism invariant SL(2) gauge theory. Using this formalism, we compute
the divergent contributions to the gravitational one-loop effective action.
Calculations of the on-shell effective action simplify greatly if one
specialises to an instanton background where only the anti-self-dual part of
the Weyl curvature is non-vanishing. One of the most striking features of the
connection formulation is that the (linearised) Euclidean action has a definite
sign, unlike in the metric case. As in the metric GR, we find the
logarithmically divergent contribution to consist of the volume and Euler
character terms, but the arising numerical constants are different. However,
the difference between the two results turns out to be always an integer. We
explain this by noting that at one loop the connection and metric based quantum
theories are closely related, the only difference being in a finite number of
scalar modes.


title:
Temperature Dependence of Thermal Conductivity of Polycrystalline
  Graphene: Thermally Enhanced Kapitza Conductance

abstract:
  Graphene has drawn wide attention due to its exceptional thermal conductivity
but complete understanding of thermal characteristics of polycrystalline
graphene is still elusive to date. For the first time, herein, we have
systematically studied the effect of temperature on the thermal conductance
behavior of polycrystalline graphene for a range of grain sizes and grain
boundary types, by using non-equilibrium molecular dynamics simulations. It is
noted that increasing the tempera-ture remarkably enhances thermal boundary
conductance (Kapitza conductance) across grain boundaries while it deteriorates
thermal conductivities of defect-free grain regions, regardless of grain sizes
and grain boundary types. This enhancement effect becomes more important for
smaller grain sizes and higher temperatures, whose normal adverse effects on
the heat transfer are thus ideally counterbalanced, making total thermal
conductivity rather robust against the temperature increment for sufficiently
small grain sizes. Upon heating from 300 to 500 K, thermal conductivity of
graphene with maximally tilted grain boundaries decreases only by 9 % for a
grain size of 50 nm in contrast to the decrease of 28 % for 250 nm, and
further, it even increases below 30 nm. We presented quantitative mapping of
its (grain, grain boundaries, and total) thermal conductivi-ties in terms with
grain sizes and temperatures, providing a guideline for graphene-based thermal
engineering and suggesting novel defect-based thermal architectures as well.


title:
Recurrence Relations of Higher Spin BPST Vertex Operators for Open
  String

abstract:
  We calculate higher spin BPST vertex operators for open bosonic string and
express these operstors in terms of Kummer function of the second kind. We
derive infinite number of recurrence relations among BPST vertex operators of
different string states. These recurrence relations among BPST vertex operators
lead to the recurrence relations among Regge string scattering amplitudes
discovered recently.


title:
Exploring a New Class of Non-stationary Spatial Gaussian Random Fields
  with Varying Local Anisotropy

abstract:
  Gaussian random fields (GRFs) constitute an important part of spatial
modelling, but can be computationally infeasible for general covariance
structures. An efficient approach is to specify GRFs via stochastic partial
differential equations (SPDEs) and derive Gaussian Markov random field (GMRF)
approximations of the solutions. We consider the construction of a class of
non-stationary GRFs with varying local anisotropy, where the local anisotropy
is introduced by allowing the coefficients in the SPDE to vary with position.
This is done by using a form of diffusion equation driven by Gaussian white
noise with a spatially varying diffusion matrix. This allows for the
introduction of parameters that control the GRF by parametrizing the diffusion
matrix. These parameters and the GRF may be considered to be part of a
hierarchical model and the parameters estimated in a Bayesian framework. The
results show that the use of an SPDE with non-constant coefficients is a
promising way of creating non-stationary spatial GMRFs that allow for physical
interpretability of the parameters, although there are several remaining
challenges that would need to be solved before these models can be put to
general practical use.


title: Inference on a Distribution Function from Ranked Set Samples

abstract:
  Consider independent observations $(X_1,R_1)$, $(X_2,R_2)$, \ldots,
$(X_n,R_n)$ with random or fixed ranks $R_i \in \{1,2,\ldots,k\}$, while
conditional on $R_i = r$, the random variable $X_i$ has the same distribution
as the $r$-th order statistic within a random sample of size $k$ from an
unknown continuous distribution function $F$. Such observation schemes are
utilized in situations in which ranking observations is much easier than
obtaining their precise values. Two well-known special cases are ranked set
sampling (McIntyre 1952) and judgement post-stratification (MacEachern et al.
2004).
  Within a general setting including unbalanced ranked set sampling we derive
and compare the asymptotic distributions of three different estimators of the
distribution function $F$ as $n \to \infty$ with fixed $k$: The stratified
estimator of Stokes and Sager (1988), the nonparametric maximum-likelihood
estimator of Kvam and Samaniego (1994) and a moment-based estimator of Chen
(2001). Our functional central limit theorems generalize and refine previous
asymptotic analyses. In addition we discuss briefly pointwise and simultaneous
confidence intervals for the distribution function $F$ with guaranteed coverage
probability for finite sample sizes.
  The methods are illustrated with a real data example, and the potential
impact of imperfect rankings is investigated in a small simulation experiment.
All in all, the moment-based estimator seems to offer a good compromise between
efficiency and robustness versus imperfect ranking, in addition to
computational efficiency.


title:
Observation of Quantum Oscillations in the Photo-assisted Shot Noise of
  a Tunnel Junction

abstract:
  We report measurements of the low frequency current fluctuations of a tunnel
junction placed at very low temperature biased by a time-dependent voltage
$V(t)=V(1+\cos 2\pi\nu t)$. We observe that the excess noise generated by the
ac excitation exhibits quantum oscillations as a function of the dc bias, with
a period given by $h\nu/e$ with $e$ the charge of a single electron. This is a
direct consequence of the quantum nature of electricity in a normal conductor.


title:
Breakdown of fast-slow analysis in an excitable system with channel
  noise

abstract:
  We consider a stochastic version of an excitable system based on the
Morris-Lecar model of a neuron, in which the noise originates from stochastic
Sodium and Potassium ion channels opening and closing. One can analyze neural
excitability in the deterministic model by using a separation of time scales
involving a fast voltage variable and a slow recovery variable, which
represents the fraction of open Potassium channels. In the stochastic setting,
spontaneous excitation is initiated by ion channel noise. If the recovery
variable is constant during initiation, the spontaneous activity rate can be
calculated using Kramer's rate theory. The validity of this assumption in the
stochastic model is examined using a systematic perturbation analysis. We find
that in most physically relevant cases, this assumption breaks down, requiring
an alternative to Kramers theory for excitable systems with one deterministic
fixed point. We also show that an exit time problem can be formulated in an
excitable system by considering maximum likelihood trajectories of the
stochastic process.


title:
The Effect of Lower Mantle Metallization on Magnetic Field Generation in
  Rocky Exoplanets

abstract:
  Recent theoretical and experimental evidence indicates that many of the
materials that are thought to exist in the mantles of terrestrial exoplanets
will metallize and become good conductors of electricity at mantle pressures.
This allows for strong electromagnetic coupling of the core and the mantle in
these planets. We use a numerical dynamo model to study the effect of a
metallized lower mantle on the dynamos of terrestrial exoplanets using several
inner core sizes and mantle conductivities.
  We find that the addition of an electrically conducting mantle results in
stronger core-mantle boundary fields because of the increase in magnetic field
stretching. We also find that a metallized mantle destabilizes the dynamo
resulting in less dipolar, less axisymmetric poloidal magnetic fields at the
core-mantle boundary. The conducting mantle efficiently screens these fields to
produce weaker surface fields. We conclude that a conducting mantle will make
the detection of extrasolar terrestrial magnetic fields more difficult, while
making the magnetic fields in the dynamo region stronger.


title: Rolling Through a Vacuum

abstract:
  We clarify under what conditions slow-roll inflation can continue almost
undisturbed, while briefly evolving through a (semi-classically) metastable
false vacuum. Furthermore, we look at potential signatures in the primordial
power spectrum that could point towards the existence of traversed metastable
false vacua. Interestingly, the theoretical constraints for the existence of
traversable metastable vacua imply that Planck should be able to detect the
resulting features in the primordial power spectrum. In other words, if Planck
does not see features this immediately implies the non-existence of metastable
false vacua rolled through during the inflationary epoch.


title: Exponential decay of correlations for generic birational maps of P^k

abstract:
  We prove the exponential decay of correlations for C^\alpha-observables
(0<\alpha =<2) for generic birational maps of P^k \`a la Bedford-Diller. In the
particular case of regular birational maps, we give a better estimate of the
speed of the decay, getting results as sharp as Dinh's results for H\'enon
maps.


title:
Decompositions of $\mathbb{R}^n, n \geq 4,$ into convex sets generate
  codimension 1 manifold factors

abstract:
  We show that if $G$ is an upper semicontinuous decomposition of
$\mathbb{R}^n$, $n \geq 4$, into convex sets, then the quotient space
$\mathbb{R}^n/G$ is a codimension one manifold factor. In particular, we show
that $\mathbb{R}^n/G$ has the disjoint arc-disk property.


title: Metastable behavior in Markov processes with internal states

abstract:
  A perturbation framework is developed to analyze metastable behavior in
stochastic processes with random internal and external states. The process is
assumed to be under weak noise conditions, and the case where the deterministic
limit is bistable is considered. A general analytical approximation is derived
for the stationary probability density and the mean switching time between
metastable states, which includes the pre exponential factor. The results are
illustrated with a model of gene expression that displays bistable switching.
In this model, the external state represents the number of protein molecules
produced by a hypothetical gene. Once produced, a protein is eventually
degraded. The internal state represents the activated or unactivated state of
the gene; in the activated state the gene produces protein more rapidly than
the unactivated state. The gene is activated by a dimer of the protein it
produces so that the activation rate depends on the current protein level. This
is a well studied model, and several model reductions and diffusion
approximation methods are available to analyze its behavior. However, it is
unclear if these methods accurately approximate long-time metastable behavior
(i.e., mean switching time between metastable states of the bistable system).
Diffusion approximations are generally known to fail in this regard.


title:
Estimation adaptative dans le mod\`ele single-index par l'approche
  d'oracle

abstract:
  In the framework of nonparametric multivariate function estimation we are
interested in structural adaptation. We assume that the function to be
estimated possesses the single-index structure where neither the link function
nor the index vector is known. We propose a novel procedure that adapts
simultaneously to the unknown index and smoothness of link function. For the
proposed procedure, we present a "local" oracle inequality (described by the
pointwise seminorm), which is then used to obtain the upper bound on the
maximal risk under regularity assumption on the link function. The lower bound
on the minimax risk shows that the constructed estimator is optimally rate
adaptive over the considered range of classes. For the same procedure we also
establish a "global" oracle inequality (under the $ L_r $ norm, $r< \infty $)
and study its performance over the Nikol'skii classes. This study shows that
the proposed method can be applied to estimating functions of inhomogeneous
smoothness.


title:
A bicategory of reduced orbifolds from the point of view of differential
  geometry - I

abstract:
  We describe a bicategory $(\mathcal{R}ed\,\mathcal{O}rb)$ of reduced
orbifolds in the framework of classical differential geometry (i.e. without any
explicit reference to notions of Lie groupoids or differentiable stacks, but
only using orbifold atlases, local lifts and changes of charts). In order to
construct such a bicategory, we first define a $2$-category
$(\mathcal{R}ed\,\mathcal{A}tl)$ whose objects are reduced orbifold atlases (on
any paracompact, second countable, Hausdorff topological space). The definition
of morphisms is obtained as a slight modification of a definition by A. Pohl,
while the definitions of $2$-morphisms and compositions of them is new in this
setup. Using the bicalculus of fractions described by D. Pronk, we are able to
construct the bicategory $(\mathcal{R}ed\,\mathcal{O}rb)$ from the $2$-category
$(\mathcal{R}ed\,\mathcal{A}tl)$. We prove that
$(\mathcal{R}ed\,\mathcal{O}rb)$ is equivalent to the bicategory of reduced
orbifolds described in terms of proper, effective, \'etale Lie groupoids by D.
Pronk and I. Moerdijk and to the $2$-category of reduced orbifolds described by
several authors in the past in terms of a suitable class of differentiable
Deligne-Mumford stacks.


title:
Metastability in a stochastic neural network modeled as a velocity jump
  Markov process

abstract:
  One of the major challenges in neuroscience is to determine how noise that is
present at the molecular and cellular levels affects dynamics and information
processing at the macroscopic level of synaptically coupled neuronal
populations. Often noise is incorprated into deterministic network models using
extrinsic noise sources. An alternative approach is to assume that noise arises
intrinsically as a collective population effect, which has led to a master
equation formulation of stochastic neural networks. In this paper we extend the
master equation formulation by introducing a stochastic model of neural
population dynamics in the form of a velocity jump Markov process. The latter
has the advantage of keeping track of synaptic processing as well as spiking
activity, and reduces to the neural master equation in a particular limit. The
population synaptic variables evolve according to piecewise deterministic
dynamics, which depends on population spiking activity. The latter is
characterised by a set of discrete stochastic variables evolving according to a
jump Markov process, with transition rates that depend on the synaptic
variables. We consider the particular problem of rare transitions between
metastable states of a network operating in a bistable regime in the
deterministic limit. Assuming that the synaptic dynamics is much slower than
the transitions between discrete spiking states, we use a WKB approximation and
singular perturbation theory to determine the mean first passage time to cross
the separatrix between the two metastable states. Such an analysis can also be
applied to other velocity jump Markov processes, including stochastic
voltage-gated ion channels and stochastic gene networks.


title: Design and operation of ARGONTUBE: a 5 m long drift liquid argon TPC

abstract:
  The Liquid Argon Time Projection Chamber (LArTPC) is a prime type of detector
for future large-mass neutrino observatories and proton decay searches. In this
paper we present the design and operation, as well as experimental results from
ARGONTUBE, a LArTPC being operated at the AEC-LHEP, University of Bern. The
main goal of this detector is to prove the feasibility of charge drift over
very long distances in liquid argon. Many other aspects of the LArTPC
technology are also investigated, such as a voltage multiplier to generate high
voltage in liquid argon (Greinacher circuit), a cryogenic purification system
and the application of multi-photon ionization of liquid argon by a UV laser.
For the first time, tracks induced by cosmic muons and UV laser beam pulses
have been observed and studied at drift distances of up to 5m, the longest
reached to date.


title:
Variable projection methods for approximate (greatest) common divisor
  computations

abstract:
  We consider the problem of finding for a given $N$-tuple of polynomials (real
or complex) the closest $N$-tuple that has a common divisor of degree at least
$d$. Extended weighted Euclidean seminorm of the coefficients is used as a
measure of closeness. Two equivalent representations of the problem are
considered: (i) direct parameterization over the common divisors and quotients
(image representation), and (ii) Sylvester low-rank approximation (kernel
representation). We use the duality between least-squares and least-norm
problems to show that (i) and (ii) are closely related to mosaic Hankel
low-rank approximation. This allows us to apply to the approximate common
divisor problem recent results on complexity and accuracy of computations for
mosaic Hankel low-rank approximation. We develop optimization methods based on
the variable projection principle both for image and kernel representation.
These methods have linear complexity in the degrees of the polynomials for
small and large $d$. We provide a software implementation of the developed
methods, which is based on a software package for structured low-rank
approximation.


title: State BCK-algebras and State-Morphism BCK-algebras

abstract:
  In the paper, we define the notion of a state BCK-algebra and a
state-morphism BCK-algebra extending the language of BCK-algebras by adding a
unary operator which models probabilistic reasoning. We present a relation
between state operators and state-morphism operators and measures and states on
BCK-algebras, respectively. We study subdirectly irreducible state (morphism)
BCK-algebras. We introduce the concept of an adjoint pair in BCK-algebras and
show that there is a one-to-one correspondence between adjoint pairs and
state-morphism operators. In addition, we show the generators of quasivarieties
of state-morphism BCK-algebras.


title:
Critical behavior and magnetic relaxation dynamics of Nd0.4Sr0.6MnO3
  nanoparticles

abstract:
  Detailed dc and ac magnetic properties of chemically synthesized
Nd0.4Sr0.6MnO3 with different particle size (down to 27 nm) have been studied
in details. We have found ferromagnetic state in the nanoparticles, whereas,
the bulk Nd0.4Sr0.6MnO3 is known to be an A-type antiferromagnet. A
Griffiths-like phase has also been identified in the nanoparticles. Further,
critical behavior of the nanoparticles has been studied around the second order
ferromagnetic-paramagnetic transition region (|(T-TC)/TC|{\pounds} 0.04) in
terms of modified Arrott plot, Kouvel-Fisher plot and critical isotherm
analysis. The estimated critical exponents (b,g,d) are quite different from
those predicted according to three-dimensional mean-field, Heisenberg and Ising
models. This signifies a quite unusual nature of the size-induced ferromagnetic
state in Nd0.4Sr0.6MnO3. The nanoparticles are found to be interacting and do
not behave like ideal superparamagnet. Interestingly, we find spin glass like
slow relaxation of magnetization, aging and memory effect in the nanometric
samples. These phenomena have been attributed to very broad distribution of
relaxation time as well as to inter-particle interaction. Experimentally, we
have found out that the dynamics of the nanoparticle systems can be best
described by hierarchical model of spin glasses.


title:
Using low moments of the Liouvillian to calculate mode lifetimes in low
  dimensional models

abstract:
  A recent proposal for practical calculation of vibrational mode lifetimes is
tested on simple, low-dimensional anharmonic models. The proposed scheme
approximates the mode lifetime in terms of ensemble averages of specific
functions in phase-space; various levels of approximation correspond to
ensemble moments of the Liouvillian. It is shown that, for systems where the
vibrational density of states is well-approximated by a single broadened peak,
the fourth-moment approximation works well over the full range of temperature.