title:
Formation of disk galaxies in preheated media: a preventative feedback
  model

abstract:
  We introduce a semi-analytic galaxy formation model implementing a
self-consistent treatment for the hot halo gas configuration and the assembly
of central disks. Using the model, we explore a preventative feedback model, in
which the circum-halo medium is assumed to be preheated up to a certain entropy
level by early starbursts or other processes, and compare it with an ejective
feedback model, in which baryons are first accreted into dark matter halos and
subsequently ejected out by feedback. The model demonstrates that when the
medium is preheated to an entropy comparable to the halo virial entropy the
baryon accretion can be largely reduced and delayed. In addition, the preheated
medium can establish an extended low density gaseous halo when it accretes into
the dark matter halos, and result in a specific angular momentum of the cooling
gas large enough to form central disks as extended as those observed. Combined
with simulated halo assembly histories, the preventative feedback model can
reproduce remarkably well a number of observational scaling relations. These
include the cold baryon (stellar plus cold gas) mass fraction-halo mass
relations, star formation histories, disk size-stellar mass relation and its
evolution, and the number density of low-mass galaxies as a function of
redshift. In contrast, the conventional ejective feedback model fails to
reproduce these observational trends. Using the model, we demonstrate that the
properties of disk galaxies are closely tied to the thermal state of hot halo
gas and even possibly the circum-halo medium, which suggests that observational
data for the disk properties and circum-galactic hot/warm medium may jointly
provide interesting constraints for galaxy formation models.


title:
First measurement of the ionization yield of nuclear recoils in liquid
  argon

abstract:
  This Letter details a measurement of the ionization yield ($Q_y$) of 6.7 keV
$^{40}Ar$ atoms stopping in a liquid argon detector. The $Q_y$ of 3.6-6.3
detected $e^{-}/\mbox{keV}$, for applied electric fields in the range 240--2130
V/cm, is encouraging for the use of this detector medium to search for the
signals from hypothetical dark matter particle interactions and from coherent
elastic neutrino nucleus scattering. A significant dependence of $Q_y$ on the
applied electric field is observed and explained in the context of ion
recombination.


title: An ODE for boundary layer separation on a sphere and a hyperbolic space

abstract:
  Ma and Wang derived an equation linking the separation location and times for
the boundary layer separation of incompressible fluid flows. The equation gave
a necessary condition for the separation (bifurcation) point. The purpose of
this paper is to generalize the equation to other geometries, and to phrase it
as a simple ODE. Moreover we consider the Navier-Stokes equation with the
Coriolis effect, which is related to the presence of trade winds on Earth.


title:
Anomalous Itinerant-Electron Metamagnetic Transition in the Layered
  Sr1-xCaxCo2P2 System

abstract:
  We report magnetic properties of the layered itinerant system,
Sr$_{1-x}$Ca$_x$Co$_2$P$_2$ in the magnetic field up to 70 T. As for the
exchange-enhanced Pauli paramagnetic metal SrCo$_2$P$_2$, the magnetization
curve shows two characteristic anomalies. The low-field anomaly is small
without obvious hysteresis, and the high-field one is a typical behavior of the
itinerant-electron metamagnetic transition (IEMT). Such a successive transition
in the magnetization curve cannot be explained by the conventional
phenomenological theory for IEMT due to the Landau expansion of the free
energy, but by the extended Landau expansion theory with distinguishable two
energy states. In the systematical study of Sr$_{1-x}$Ca$_x$Co$_2$P$_2$,
furthermore, the metamagnetic transition field decreases and goes to zero as
$x$ increases up to 0.5, indicating that the ferromagnetic quantum critical
point (QCP) exists at $x \sim 0.5$.


title:
Diagonal recurrence relations, inequalities, and monotonicity related to
  Stirling numbers

abstract:
  In the paper, the author derives several "diagonal" recurrence relations,
constructs some inequalities, finds monotonicity, and poses a conjecture
related to Stirling numbers of the second kind.


title: On the binomial edge ideals of block graphs

abstract:
  We find a class of block graphs whose binomial edge ideals have minimal
regularity. As a consequence, we characterize the trees whose binomial edge
ideals have minimal regularity. Also, we show that the binomial edge ideal of a
block graph has the same depth as its initial ideal.


title:
Ad Hoc Networking With Cost-Effective Infrastructure: Generalized
  Capacity Scaling

abstract:
  Capacity scaling of a large hybrid network with unit node density, consisting
of $n$ wireless ad hoc nodes, base stations (BSs) equipped with multiple
antennas, and one remote central processor (RCP), is analyzed when wired
backhaul links between the BSs and the RCP are rate-limited. We deal with a
general scenario where the number of BSs, the number of antennas at each BS,
and the backhaul link rate can scale at arbitrary rates relative to $n$ (i.e.,
we introduce three scaling parameters). We first derive the minimum backhaul
link rate required to achieve the same capacity scaling law as in the
infinite-capacity backhaul link case. Assuming an arbitrary rate scaling of
each backhaul link, a generalized achievable throughput scaling law is then
analyzed in the network based on using one of pure multihop, hierarchical
cooperation, and two infrastructure-supported routing protocols, and moreover,
three-dimensional information-theoretic operating regimes are explicitly
identified according to the three scaling parameters. In particular, we show
the case where our network having a power limitation is also fundamentally in
the degrees-of-freedom- or infrastructure-limited regime, or both. In addition,
a generalized cut-set upper bound under the network model is derived by cutting
not only the wireless connections but also the wired connections. It is shown
that our upper bound matches the achievable throughput scaling even under
realistic network conditions such that each backhaul link rate scales slower
than the aforementioned minimum-required backhaul link rate.


title:
Approachability in unknown games: Online learning meets multi-objective
  optimization

abstract:
  In the standard setting of approachability there are two players and a target
set. The players play repeatedly a known vector-valued game where the first
player wants to have the average vector-valued payoff converge to the target
set which the other player tries to exclude it from this set. We revisit this
setting in the spirit of online learning and do not assume that the first
player knows the game structure: she receives an arbitrary vector-valued reward
vector at every round. She wishes to approach the smallest ("best") possible
set given the observed average payoffs in hindsight. This extension of the
standard setting has implications even when the original target set is not
approachable and when it is not obvious which expansion of it should be
approached instead. We show that it is impossible, in general, to approach the
best target set in hindsight and propose achievable though ambitious
alternative goals. We further propose a concrete strategy to approach these
goals. Our method does not require projection onto a target set and amounts to
switching between scalar regret minimization algorithms that are performed in
episodes. Applications to global cost minimization and to approachability under
sample path constraints are considered.


title: A Second-order Bound with Excess Losses

abstract:
  We study online aggregation of the predictions of experts, and first show new
second-order regret bounds in the standard setting, which are obtained via a
version of the Prod algorithm (and also a version of the polynomially weighted
average algorithm) with multiple learning rates. These bounds are in terms of
excess losses, the differences between the instantaneous losses suffered by the
algorithm and the ones of a given expert. We then demonstrate the interest of
these bounds in the context of experts that report their confidences as a
number in the interval [0,1] using a generic reduction to the standard setting.
We conclude by two other applications in the standard setting, which improve
the known bounds in case of small excess losses and show a bounded regret
against i.i.d. sequences of losses.


title: Golden ratio autocorrelation function and the exponential decay

abstract:
  An autocorrelation function is obtained on the base of the recurrence
relation formalism, whose continued fraction form corresponds to that of golden
ratio. It turns out that this GR autocorrelation is known in science and obeys
all necessary conditions, in contrast to the exponential autocorrelation
function. Using the Kubo approach it is shown how exponential correlations
appear in the linear response theory as a result of non-Hermitian relaxation of
the system.


title:
Rock around the Clock: An Agent-Based Model of Low- and High-Frequency
  Trading

abstract:
  We build an agent-based model to study how the interplay between low- and
high-frequency trading affects asset price dynamics. Our main goal is to
investigate whether high-frequency trading exacerbates market volatility and
generates flash crashes. In the model, low-frequency agents adopt trading rules
based on chronological time and can switch between fundamentalist and chartist
strategies. On the contrary, high-frequency traders activation is event-driven
and depends on price fluctuations. High-frequency traders use directional
strategies to exploit market information produced by low-frequency traders.
Monte-Carlo simulations reveal that the model replicates the main stylized
facts of financial markets. Furthermore, we find that the presence of
high-frequency trading increases market volatility and plays a fundamental role
in the generation of flash crashes. The emergence of flash crashes is explained
by two salient characteristics of high-frequency traders, i.e. their ability to
i) generate high bid-ask spreads and ii) synchronize on the sell side of the
limit order book. Finally, we find that higher rates of order cancellation by
high-frequency traders increase the incidence of flash crashes but reduce their
duration.


title:
Axial-vector $f_1(1285)-f_1(1420)$ mixing and $B_s \to J/\psi
  (f_1(1285), f_1(1420))$ decays

abstract:
  Inspired by the very recent LHCb measurements of $B_s \to J/\psi f_1(1285)$
and the good agreement between the perturbative QCD predictions and the data
for many $B \to J/\psi V$ decays, we here investigate the $B_s \to J/\psi
f_1(1285)$ and $B_s \to J/\psi f_1(1420)$ decays for the first time by
employing the perturbative QCD (pQCD) approach, in which the $1^3P_1$ states
$f_1(1285)$ and $f_1(1420)$ are believed to be the mixture of flavor singlet
$f_1$ and octet $f_8$ or of quark-flavor states $f_{1q}$ and $f_{1s}$. We show
that the pQCD predictions for the branching ratio of $B_s \to J/\psi f_1(1285)$
agree well with the data within errors for the mixing angle $\theta_{^3P_1}
\approx 20^\circ (\phi_{^3P_1} \approx 15^\circ)$ between $f_1 (f_{1q})$ and
$f_8 (f_{1s})$ states. Furthermore, the branching ratio of $B_s \to J/\psi
f_1(1420)$ and the large transverse polarization fractions in these two
considered channels are also predicted and will be tested by the LHC and the
forthcoming Super-B factory experiments. Based on the decay rates of $B_s \to
J/\psi f_1(1285)$ and $B_s \to J/\psi f_1(1420)$ decay modes predicted in the
pQCD approach, the extracted mixing angle between $f_1(1285)$ and $f_1(1420)$
is basically consistent with currently available experimental measurements and
lattice QCD analysis within still large theoretical errors.


title: No pair production of open strings in a plane-wave background

abstract:
  We consider whether an external electric field may cause the pair production
of open strings in a type IIA plane-wave background. The boundary states of
D-branes with condensates are constructed in the Green-Schwarz formulation of
superstring theory with the light-cone gauge. The cylinder diagrams are
computed with massive theta functions. Although the value of the electric field
is bounded by the upper value, there is no pole in the amplitudes and it
indicates that no pair production occurs in the plane-wave background. This
result would be universal for a class of plane-wave backgrounds.


title:
A proof of the Kawamata-Morrison Cone Conjecture for holomorphic
  symplectic varieties of K3^[n] or generalized Kummer deformation type

abstract:
  We prove a version of the Kawamata-Morrison ample cone conjecture for
projective irreducible holomorphic symplectic manifolds deformation equivalent
to either the Hilbert scheme of n points on a K3 surface, or a generalized
Kummer variety.


title: Finite covering projections of noncommutative torus

abstract:
  This article contains is concerned with noncommutative analogue of
topological finitely listed covering projections. In my previous article I have
already find a family of covering projections of the noncommutative torus. This
article describes all covering projections of the noncommutative torus.


title:
Generalized Bi-Schr\"odinger Flows and Vortex Filament on Symmetric Lie
  Algebras

abstract:
  The theory of the vortex filament in three-dimensional fluid dynamics,
consisting mainly of the models up to the third-order approximation, is an
attractive subject in both physics and mathematics. Many efforts have been
devoted to the extension of the theory to higher-dimensional symmetric Lie
algebras. However, such a generalization known in literature is strongly
restricted by the integrable method. In this article, we endeavor to establish
the third-order models of the vortex filament on symmetric Lie algebras in a
purely geometric way by generalized bi-Schr\"odinger flows. Our generalization
overcomes the limitation of integrability and creates successfully the desired
models on Hermitian or para-Hermitian symmetric Lie algebras. Combining the
result in this article with what have been known in literature for the
leading-order and the second-order models, we actually exhibit the basic models
and the related theory of the vortex filament on symmetric Lie algebras up to
the third-order approximation.


title: Flavor structure in D-brane models: Majorana neutrino masses

abstract:
  We study the flavor structure in intersecting D-brane models. We study
anomalies of the discrete flavor symmetries. We analyze the Majorana neutrino
masses, which can be generated by D-brane instanton effects. It is found that a
certain pattern of mass matrix is obtained and the cyclic permutation symmetry
remains unbroken. As a result, trimaximal mixing matrix can be realized if
Dirac neutrino mass and charged lepton mass matrices are diagonal.


title:
Quantum key distribution based on quantum dimension and independent
  devices

abstract:
  In this paper, we propose a quantum key distribution (QKD) protocol based on
only a two-dimensional Hilbert space encoding a quantum system and independent
devices between the equipment for state preparation and measurement. Our
protocol is inspired by the fully device-independent quantum key distribution
(FDI-QKD) protocol and the measurement-device-independent quantum key
distribution (MDI-QKD) protocol. Our protocol only requires the state to be
prepared in the two dimensional Hilbert space, which weakens the state
preparation assumption in the original MDI-QKD protocol. More interestingly,
our protocol can overcome the detection loophole problem in the FDI-QKD
protocol, which greatly limits the application of FDI-QKD. Hence our protocol
can be implemented with practical optical components.


title: Homology of a Leavitt Path Algebra via Anick's Resolution

abstract:
  The aim of this paper is to calculate the homology of a Leavitt path algebra
via Anick's resolution. We show that all homology (in positive degrees) of a
Leavitt path algebra is equal to zero.


title: Imaging of Spatial Correlations of Two-Photon States

abstract:
  We use a fiber based double slit Young interferometer for studying the
far-field spatial distribution of the two-photon coincidence rate (coincidence
pattern) for various quantum states with different degree of spatial
entanglement. The realized experimental approach allows to characterize
coincidence patterns for different states without any modifications of the
setup. Measurements were carried out with path-entangled and separable states.
The dependence of the coincidence pattern on the phase of the interferometer
for superposition and separable states was studied. The results have
implications for using of nonclassical light in multiphoton imaging, quantum
lithography, and studies of phase decoherence.


title: Key parameters generation of the navigation data of GPS Simulator

abstract:
  The development of the GPS (Global Positioning System) signal simulator
involving to a number of key technologies, in which the generation of
navigation message has important significance. Based on analysis of the
structure of GPS navigation data, the paper researches the production of
telemetry word and handover word, parity check code, time parameters and star
clock. Using disturbing force equation and Lagrange planetary motion equation
extrapolate ephemeris parameters whose feasibility is verified through the
Matlab software finally.


title:
Robustness of complex many-body networks: Novel perspective in 2D
  metal-insulator transition

abstract:
  We present a novel theoretical framework established by complex network
analysis for understanding the phase transition beyond the Landau symmetry
breaking paradigm. In this paper we take a two-dimensional metal-insulator
transition driven by electron correlations for example. Passing through the
transition point, we find a hidden symmetry broken in the network space, which
is invisible in real space. This symmetry is nothing but a kind of robustness
of the network to random failures. We then show that a network quantity,
small-worldness, is capable of identifying the phase transition with/without
any symmetry breaking in the real space and behaving as a new order parameter
in the network space. We demonstrate that whether or not the symmetry is broken
in real space a variety of phase transitions in condensed matters can be
characterized by the hidden symmetry breaking in the weighted network, that is
to say, a decline in network robustness.


title: Probabilistic Interpretation of Linear Solvers

abstract:
  This manuscript proposes a probabilistic framework for algorithms that
iteratively solve unconstrained linear problems $Bx = b$ with positive definite
$B$ for $x$. The goal is to replace the point estimates returned by existing
methods with a Gaussian posterior belief over the elements of the inverse of
$B$, which can be used to estimate errors. Recent probabilistic interpretations
of the secant family of quasi-Newton optimization algorithms are extended.
Combined with properties of the conjugate gradient algorithm, this leads to
uncertainty-calibrated methods with very limited cost overhead over conjugate
gradients, a self-contained novel interpretation of the quasi-Newton and
conjugate gradient algorithms, and a foundation for new nonlinear optimization
methods.

categories: math.OC cs.LG cs.NA math.NA math.PR stat.ML


title: The large-N running of the spectral index of inflation

abstract:
  We extend previous classifications of inflationary models by means of their
behaviour at large-N, where N is the number of e-foldings. In addition to the
perturbative 1/N case, whose slow-roll parameters fall off as powers of 1/N, we
introduce the constant, non-perturbative and logarithmic classes. This covers
the large majority of inflationary models. Furthermore, we calculate the
running of the spectral tilt for all these classes. Remarkably, we find that
the tilt's runnings essentially cluster around the permil level. We comment on
the implications for future experiments.


title:
The application of spectrum standardization method for carbon analysis
  in coal using laser-induced breakdown spectroscopy

abstract:
  Measurements of carbon content in coal using laser-induced breakdown
spectroscopy (LIBS) is limited by its low measurement precision and accuracy. A
spectrum standardization method was proposed to achieve both reproducible and
accurate results for the quantitative analysis of carbon content in coal with
LIBS. The proposed method utilized the molecular carbon emissions to compensate
the diminution of atomic carbon emission caused by matrix effect. The
compensated carbon line intensities were further converted into an assumed
standard state with fixed plasma temperature, electron density, and total
number density of elemental carbon, which is proportional to its concentration
in the coal samples. In addition, in order to obtained better compensation for
total carbon number density fluctuations, an iterative algorithm was applied,
which is different from our previous standardization calculations. The modified
spectrum standardization model was applied to the measurement of carbon content
in 24 bituminous coal samples. The results demonstrated that the proposed
method had superior performance over the generally applied normalization
methods. The average relative standard deviation, the coefficient of
determination, the root-mean-square error of prediction, and the average
maximum relative error for the modified model were 3.44%, 0.83, 2.71%, and
12.61%, respectively, while the corresponding values for the normalization with
segmental spectrum area were 6.00%, 0.75, 3.77%, and 15.40%, respectively,
showing an overwhelming improvement.


title:
On a time and space discretized approximation of the Boltzmann equation
  in the whole space

abstract:
  In this paper, convergence results on the solutions of a time and space
discrete model approximation of the Boltzmann equation for a gas of Maxwellian
particles in a bounded domain, obtained by Babovsky and Illner [1989], are
extended to approximate the solutions of the Boltzmann equation in the whole
physical space. This is done for a class of particle interactions including
Maxwell and soft cut-off potentials in the sense of Grad.
  The main result shows that the solutions of the discrete model converge in
$\mathbb{L}^1$ to the solutions of the Boltzmann equation, when the
discretization parameters go simultaneously to zero. The convergence is uniform
with respect to the discretization parameters.
  In addition, a sufficient condition for the implementation of the main result
is provided.


title:
A model combining spectrum standardization and dominant factor based
  partial least square method for carbon analysis in coal by laser-induced
  breakdown spectroscopy

abstract:
  Successful quantitative measurement of carbon content in coal using
laser-induced breakdown spectroscopy (LIBS) is suffered from relatively low
precision and accuracy. In the present work, the spectrum standardization
method was combined with the dominant factor based partial least square (PLS)
method to improve the measurement accuracy of carbon content in coal by LIBS.
The combination model employed the spectrum standardization method to convert
the carbon line intensity into standard state for more accurately calculating
the dominant carbon concentration, and then applied PLS with full spectrum
information to correct the residual errors. The combination model was applied
to the measurement of carbon content for 24 bituminous coal samples. The
results demonstrated that the combination model could further improve the
measurement accuracy compared with both our previously established spectrum
standardization model and dominant factor based PLS model using spectral area
normalized intensity for the dominant factor model. For example, the
coefficient of determination (R2), the root-mean-square error of prediction
(RMSEP), and the average relative error (ARE) for the combination model were
0.99, 1.75%, and 2.39%, respectively; while those values for the spectrum
standardization method were 0.83, 2.71%, and 3.40%, respectively; and those
values for the dominant factor based PLS model were 0.99, 2.66%, and 3.64%,
respectively.


title: Non-adiabatic spherical collapse with a two-fluid atmosphere

abstract:
  In this work we present an exact model of a spherically symmetric star
undergoing dissipative collapse in the form of a radial heat flux. The interior
of the star is matched smoothly to the generalised Vaidya line element
representing a two-fluid atmosphere comprising null radiation and a string
fluid. The influence of the string density on the thermal behaviour of the
model is investigated by employing a causal heat transport equation of
Maxwell-Cattaneo form.


title: Fractional covers and matchings in families of weighted $d$-intervals

abstract:
  A $d$-{\em interval} is a union of at most $d$ disjoint closed intervals on a
fixed line. Tardos [Combinatorica 15 (1995), 123-134] and the second author
[Disc. Comput. Geom. 18 (1997), 195-203] used topological tools to bound the
transversal number $\tau$ of a family $H$ of $d$-intervals in terms of $d$ and
the matching number $\nu$ of $H$. We investigate the weighted and fractional
versions of this problem and prove upper bounds that are tight up to constant
factors. We apply both the topological method and an approach of Alon [Disc.
Comput. Geom. 19 (1998), 333-334]. For the use of the latter, we prove a
weighted version of Tur\'{a}n's theorem. We also provide a proof of the second
author's upper bound that is more direct than the original proof.


title: Resolvent estimates for the magnetic Schrodinger operator

abstract:
  We prove optimal high-frequency resolvent estimates for perturbations by
large magnetic and electric potentials


title:
Distributed Robustness Analysis of Interconnected Uncertain Systems
  Using Chordal Decomposition

abstract:
  Large-scale interconnected uncertain systems commonly have large state and
uncertainty dimensions. Aside from the heavy computational cost of solving
centralized robust stability analysis techniques, privacy requirements in the
network can also introduce further issues. In this paper, we utilize IQC
analysis for analyzing large-scale interconnected uncertain systems and we
evade these issues by describing a decomposition scheme that is based on the
interconnection structure of the system. This scheme is based on the so-called
chordal decomposition and does not add any conservativeness to the analysis
approach. The decomposed problem can be solved using distributed computational
algorithms without the need for a centralized computational unit. We further
discuss the merits of the proposed analysis approach using a numerical
experiment.


title:
Nonuniform dichotomy spectrum and reducibility for nonautonomous
  equations

abstract:
  For nonautonomous linear differential equations with nonuniform
hyperbolicity, we introduce a definition for nonuniform dichotomy spectrum,
which can be seen as a generalization of Sacker-Sell spectrum. We prove a
spectral theorem and use the spectral theorem to prove a reducibility result.


title:
Application of TauSpinner for studies on tau-lepton polarization and
  spin correlations in Z, W and H decays at LHC

abstract:
  The tau-lepton plays an important role in the physics program at LHC. Its
spin can be used for separation of signal from background or in measuring
properties of New Particles decaying to tau leptons.
  The TauSpinner package represents a tool to modify tau spin effects in any
sample containing tau leptons. Generated events, featuring taus produced from
intermediate state W, Z, H bosons can be used as an input. The information on
the polarization and spin correlations is reconstructed from the kinematics of
the tau lepton(s) (nutau in case of W-mediated processes) and tau decay
products. By weights, attributed on the event-by-event basis, it enables
numerical evaluation and/or modification of the spin effects.
  We review distributions to monitor spin effects in leptonic and hadronic tau
decays with up to three pions, to provide benchmarks for validation of spin
content of the event sample and to visualize the tau lepton spin polarization
and correlation effects. The demonstration examples for use of TauSpinner
libraries, are documented. New validation methods of such an approach are
provided. Other topics, like TauSpinner systematic errors or sensitivity of
experimental distributions to spin, are addressed in part only.
  This approach is of interest for implementation of spin effects in embedded
tau lepton samples, where Z to mu mu events from data of muons are replaced by
simulated tau leptons. Embedding is used at LHC for estimating Z to tau tau
background to H to tau tau signatures.


title:
Gas-liquid phase coexistence and crossover behavior of binary ionic
  fluids with screened Coulomb interactions: The effect of an interaction range

abstract:
  We study the gas-liquid phase diagram and the crossover behavior of a simple
model of ionic fluid: an equimolar binary mixture of equisized hard spheres
interacting through screened Coulomb potentials which are repulsive between
particles of the same species and attractive between particles of different
species. Using our previous results, we obtain explicit expressions for the
relevant coefficients of the effective $\varphi^{4}$ Ginzburg-Landau
Hamiltonian in a one-loop approximation. Within the framework of this
approximation, we calculate the critical parameters and gas-liquid coexistence
curves for different values of the dimensionless inverse screening length $z$.
The critical temperature scaled by the Yukawa potential contact value as well
as the critical packing fraction rapidly decrease with an increase of the
interaction range and then for $z<0.05$ slowly approach the values found for a
purely ionic model, i.e., a restricted primitive model (RPM). The both trends
are qualitatively consistent with the results of Monte Carlo simulations. We
find that gas-liquid coexistence region reduces with an increase of $z$ and
completely vanishes at $z\simeq 2.781$. This qualitatively agrees with the
results of Monte Carlo simulations indicating a stable gas-liquid coexistence
for $z\leq 4$. It is also shown that an increase in the interaction range from
the one typical of simple fluids to the one typical of ionic fluids leads to a
decrease of the crossover temperature. For $z\simeq 0.01$, the crossover
temperature is the same as for the RPM. For $z\simeq 2.781$, our results
indicate a tricritical point.


title: Softness of Sn isotopes in relativistic semi-classical approximation

abstract:
  Within the frame-work of relativistic Thomas-Fermi and relativistic extended
Thomas-Fermi approximations, we calculate the giant monopole resonance (GMR)
excitation energies for Sn and related nuclei. A large number of non-linear
relativistic force parameters are used in this calculations. We find that a
parameter set is capable to reproduce the experimental monopole energy of Sn
isotopes, when its nuclear matter compressibility lies within $210-230$ MeV,
however fails to reproduce the GMR energy of other related nuclei. That means,
simultaneously a parameter set can not reproduce the GMR values of Sn and other
nuclei.


title: Attribute Dependencies for Data with Grades

abstract:
  This paper examines attribute dependencies in data that involve grades, such
as a grade to which an object is red or a grade to which two objects are
similar. We thus extend the classical agenda by allowing graded, or fuzzy,
attributes instead of Boolean attributes in case of attribute implications, and
allowing approximate match based on degrees of similarity instead of exact
match in case of functional dependencies. In a sense, we move from bivalence,
inherently present in the now-available theories of dependencies, to a more
flexible setting that involves grades. Such a shift has far-reaching
consequences. We argue that a reasonable theory of dependencies may be
developed by making use of mathematical fuzzy logic. Namely, the theory of
dependencies is then based on a solid logic calculus the same way the classical
dependencies are based on classical logic. For instance, rather than handling
degrees of similarity in an ad hoc manner, we consistently treat them as truth
values, the same way as true (match) and false (mismatch) are treated in
classical theories. In addition, several notions intuitively embraced in the
presence of grades, such as a degree of validity of a particular dependence or
a degree of entailment, naturally emerge and receive a conceptually clean
treatment in the presented approach. In the paper, we discuss motivations,
provide basic notions of syntax and semantics, and develop basic results which
include entailment of dependencies, associated closure structures, a logic of
dependencies with two versions of completeness theorem, results and algorithms
regarding complete non-redundant sets of dependencies, relationship to and a
possible reductionist interface to classical dependencies, and relationship to
functional dependencies over domains with similarity.


title: Black Holes as Beads on Cosmic Strings

abstract:
  We consider the possibility of formation of cosmic strings with black holes
as beads. We focus on the simplest setup where two black holes are formed on a
long cosmic string. It turns out the in absence of a background magnetic field
and for observationally viable values for cosmic string tensions, $\mu<2\times
10^{-7}$, the tension of the strut in between the black holes has to be less
than the ones that run into infinity. This result does not change if a
cosmological constant is present. However if the background magnetic field is
turned on, we can have stable setups where the tensions of all cosmic strings
are equal. We derive the equilibrium conditions in each of these setups
depending on whether the black holes are extremal or non-extremal. We obtain
cosmologically acceptable solutions with solar mass black holes and
intragalactic strength cosmic magnatic field.


title:
Mining Images in Biomedical Publications: Detection and Analysis of Gel
  Diagrams

abstract:
  Authors of biomedical publications use gel images to report experimental
results such as protein-protein interactions or protein expressions under
different conditions. Gel images offer a concise way to communicate such
findings, not all of which need to be explicitly discussed in the article text.
This fact together with the abundance of gel images and their shared common
patterns makes them prime candidates for automated image mining and parsing. We
introduce an approach for the detection of gel images, and present a workflow
to analyze them. We are able to detect gel segments and panels at high
accuracy, and present preliminary results for the identification of gene names
in these images. While we cannot provide a complete solution at this point, we
present evidence that this kind of image mining is feasible.


title: Evolution and defect analysis of vertical graphene nanosheets

abstract:
  We report catalyst-free direct synthesis of vertical graphene nanosheets
(VGNs) on SiO2/Si and quartz substrates using microwave electron cyclotron
resonance - plasma enhanced chemical vapor deposition. The evolution of VGNs is
studied systematically at different growth stages. Raman analysis as a function
of growth time reveals that two different disorder-induced competing mechanisms
contributing to the defect band intensity. The VGNs grown on SiO2/Si substrates
predominantly consists of both vacancy-like and hopping defects. On the other
hand, the VGNs grown on quartz substrates contain mainly boundary-like defects.
XPS studies also corroborate Raman analysis in terms of defect density and
vacancy-like defects for the VGNs grown on SiO2/Si substrates. Moreover, the
grown VGNs exhibit a high optical transmittance from 95 to 78 % at 550 nm and
the sheet resistance varies from 30 to 2.17 kohms/square depending on growth
time.


title:
A search for small and medium scale anisotropy of cosmic rays above 1
  PeV registered at the Tunka-133 array

abstract:
  A search for anisotropy at different scales in the arrival directions of
cosmic rays with energies above 1 PeV is performed with data of the Tunka-133
array. A number of regions with angular sizes up to approximately 30 degrees
that deviate from the uniform background with a statistical significance
greater than three standard deviations are found using the shuffling technique
both in the complete data set and its subsets in different energy ranges. Some
regions with an excess of cosmic rays correlate with the distribution of
possible cosmic ray sources. A comparison of the results with a similar
analysis of the legacy data of the EAS MSU array is presented.


title:
Strong restriction on inflationary vacua from the local gauge invariance
  III: Infrared regularity of graviton loops

abstract:
  It has been claimed that the super Hubble modes of the graviton generated
during inflation can make loop corrections diverge. Even if we introduce an
infrared (IR) cutoff at a comoving scale as an ad hoc but a practical way for
the regularization, we encounter the secular growth, which may lead to the
breakdown of perturbative expansion for a sufficiently long lasting inflation.
In this paper, we show that the IR pathology concerning the graviton can be
attributed to the presence of residual gauge degrees of freedom in the local
observable universe as in the case of the adiabatic curvature perturbation. We
will show that choosing the Euclidean vacuum as the initial state ensures the
invariance under the above-mentioned residual gauge transformations. We will
also show that as long as we consider a gauge invariant quantity in the local
universe, we encounter neither the IR divergence nor the secular growth. The
argument in this paper applies to general single field models of inflation up
to a sufficiently high order in perturbation.


title: Exact solutions and their interpretation - session A1

abstract:
  We report on the oral contributions and give a list of posters presented in
the session A1 "Exact solutions and their interpretation" at the 20th
International Conference on General Relativity and Gravitation (GR 20) in
Warsaw, July 7-13, 2013.


title: Quantum-elastic bump on a surface

abstract:
  We use an exact solution of the elastic membrane shape equation, representing
the curvature, which will serve as a quantum potential in the quantum
mechanical two dimensional Schrodinger equation for a (quasi-) particle on the
surface of the membrane. Surface curvature in the quasi one-dimensional case is
related to an unexpected static formation: on one hand the elastic energy has a
maximum where surface curvature has a maximum and on the other hand the
concentration of the expectation value to find the (quasi-) particle is again
where the elastic energy is concentrated, namely where surface curvature has a
maximum. This represents a particular form of a conformon.


title:
Freedom From Restriction, Freedom Of A Restriction: A Comparison Of Some
  Open Source Software Licenses

abstract:
  There is a multitude of licenses out there for a software developer to choose
from, but a lot of programmers would prefer to not have to have a legal degree
in order to understand them and would rather just have their code out in the
public being used. This paper examines a few of the more popular and common
software licenses available and compares their conditions from the perspective
that a developer wanted to scratch their proverbial itch, have their code be
used and maybe even get credit for it. This paper attempts to clarify which
license a developer would benefit from the most if they just want to have their
code used, have their name out there and not be sued if anything breaks.


title:
Auger neutralization and ionization processes for charge exchange
  between slow noble gas atoms and solid surfaces

abstract:
  Electron and energy transfer processes between an atom or molecule and a
surface are extremely important for many applications in physics and chemistry.
Therefore a profound understanding of these processes is essential in order to
analyze a large variety of physical systems. The microscopic description of the
two-electron Auger processes, leading to neutralization/ionization of an
ion/neutral atom in front of a solid surface, has been a long-standing problem.
It can be dated back to the 1950s when H. D. Hagstrum proposed to use the
information contained in the spectrum of the electrons emitted during the
neutralization of slow noble gas ions as a surface analytical tool
complementing photoelectron spectroscopy. However, only recently a
comprehensive description of the Auger neutralization mechanism has been
achieved by the combined efforts of theoretical and experimental methods. In
this article we review the theoretical models for this problem, stressing how
their outcome compare with experimental results. We also analyze the inverse
problem of Auger ionization. We emphasize the understanding of the key
quantities governing the processes and outline the challenges remaining. This
opens new perspectives for future developments of theoretical and experimental
work in this field.


title:
Near-unity coupling efficiency of a quantum emitter to a
  photonic-crystal waveguide

abstract:
  A quantum emitter efficiently coupled to a nanophotonic waveguide constitutes
a promising system for the realization of single-photon transistors,
quantum-logic gates based on giant single-photon nonlinearities, and high
bit-rate deterministic single-photon sources. The key figure of merit for such
devices is the $\beta$-factor, which is the probability for an emitted single
photon to be channeled into a desired waveguide mode. We report on the
experimental achievement of $\beta = 98.43 \pm 0.04\%$ for a quantum dot
coupled to a photonic-crystal waveguide, corresponding to a single-emitter
cooperativity of $\eta = 62.7 \pm 1.5$. This constitutes a nearly ideal
photon-matter interface where the quantum dot acts effectively as a 1D
"artificial" atom, since it interacts almost exclusively with just a single
propagating optical mode. The $\beta$-factor is found to be remarkably robust
to variations in position and emission wavelength of the quantum dots. Our work
demonstrates the extraordinary potential of photonic-crystal waveguides for
highly efficient single-photon generation and on-chip photon-photon
interaction.


title: Applications to quantum gravity from C*-bundles

abstract:
  Applications to quantum gravity of some results in C*-algebras are developed.
We open by describing why algebra may be an integral aspect of quantum gravity.
By interpreting the inner automorphisms of a C*-algebra as families of parallel
transports on a C*-bundle, we define a notion of generalised connection for
C*-bundles, implying that C*-bundle dynamical systems can be used to study a
Dirac operator's spectrum and also the generator of the modular group. The fact
that their dynamics preserves the bundle structure, means that C*-bundle
dynamical systems are relativistic systems. We describe a 2-category to unify
Einstein's two uses of the phrase general covariance, give concrete examples
and construct a generally covariant quantum system. Motivations include the
point of view of virtual points hiding in fibres of a C*-bundle over $X$ and
that physical geometry is instrinsically non-local.


title: Equivalent Moser type inequalities in R2 and the zero mass case

abstract:
  We first investigate concentration and vanishing phenomena concerning Moser
type inequalities in the whole plane which involve complete and reduced Sobolev
norms. In particular we show that the critical Ruf inequality is equivalent to
an improved version of the subcritical Adachi-Tanaka inequality which we prove
to be attained. Then, we consider the limiting space
$\mathcal{D}^{1,2}(\mathbb{R}^2)$, completion of smooth compactly supported
functions with respect to the Dirichlet norm $\|\nabla\cdot\|_2$, and we prove
an optimal Lorentz-Zygmund type inequality with explicit extremals and from
which can be derived classical inequalities in $H^1(\mathbb{R}^2)$ such as the
Adachi-Tanaka inequality and a version of Ruf's inequality.


title:
Black Hole Entropy in Loop Quantum Gravity, Analytic Continuation, and
  Dual Holography

abstract:
  A new approach to black hole thermodynamics is proposed in Loop Quantum
Gravity (LQG), by defining a new black hole partition function, followed by
analytic continuations of Barbero-Immirzi parameter to $\gamma\in i\mathbb{R}$
and Chern-Simons level to $k\in i\mathbb{R}$. The analytic continued partition
function has remarkable features: The black hole entropy $S=A/4\ell_P^2$ is
reproduced correctly for infinitely many $\gamma= i\eta$, at least for
$\eta\in\mathbb{Z}\setminus\{0\}$. The near-horizon Unruh temperature emerges
as the pole of partition function. Interestingly, by analytic continuation the
partition function can have a dual statistical interpretation corresponding to
a dual quantum theory of $\gamma\in i\mathbb{Z}$. The dual quantum theory
implies a semiclassical area spectrum for $\gamma\in i\mathbb{Z}$. It also
implies that at a given near horizon (quantum) geometry, the number of quantum
states inside horizon is bounded by a holographic degeneracy $d=
e^{A/4\ell_P}$, which produces the Bekenstein bound from LQG.
  On the other hand, the result in arXiv:1212.4060 receives a justification
here.


title:
Large degree asymptotics of orthogonal polynomials with respect to an
  oscillatory weight on a bounded interval

abstract:
  We consider polynomials $p_n^{\omega}(x)$ that are orthogonal with respect to
the oscillatory weight $w(x)=e^{i\omega x}$ on $[-1,1]$, where $\omega>0$ is a
real parameter. A first analysis of $p_n^{\omega}(x)$ for large values of
$\omega$ was carried out in connection with complex Gaussian quadrature rules
with uniform good properties in $\omega$. In this contribution we study the
existence, asymptotic behavior and asymptotic distribution of the roots of
$p_n^{\omega}(x)$ in the complex plane as $n\to\infty$. The parameter $\omega$
grows with $n$ linearly. The tools used are logarithmic potential theory and
the $S$-property, together with the Riemann--Hilbert formulation and the
Deift--Zhou steepest descent method.


title:
Guaranteed Non-quadratic Performance for Quantum Systems with Nonlinear
  Uncertainties

abstract:
  This paper presents a robust performance analysis result for a class of
uncertain quantum systems containing sector bounded nonlinearities arising from
perturbations to the system Hamiltonian. An LMI condition is given for
calculating a guaranteed upper bound on a non-quadratic cost function. This
result is illustrated with an example involving a Josephson junction in an
electromagnetic cavity.


title: Connected Colourings of Complete Graphs and Hypergraphs

abstract:
  Gallai's colouring theorem states that if the edges of a complete graph are
3-coloured, with each colour class forming a connected (spanning) subgraph,
then there is a triangle that has all 3 colours. What happens for more colours:
if we $k$-colour the edges of the complete graph, with each colour class
connected, how many of the $\binom{k}{3}$ triples of colours must appear as
triangles?
  In this note we show that the `obvious' conjecture, namely that there are
always at least $\binom{k-1}{2}$ triples, is not correct. We determine the
minimum asymptotically. This answers a question of Johnson. We also give some
results about the analogous problem for hypergraphs, and we make a conjecture
that we believe is the `right' generalisation of Gallai's theorem to
hypergraphs.


title:
Signal Reconstruction Framework Based On Projections Onto Epigraph Set
  Of A Convex Cost Function (PESC)

abstract:
  A new signal processing framework based on making orthogonal Projections onto
the Epigraph Set of a Convex cost function (PESC) is developed. In this way it
is possible to solve convex optimization problems using the well-known
Projections onto Convex Set (POCS) approach. In this algorithm, the dimension
of the minimization problem is lifted by one and a convex set corresponding to
the epigraph of the cost function is defined. If the cost function is a convex
function in $R^N$, the corresponding epigraph set is also a convex set in
R^{N+1}. The PESC method provides globally optimal solutions for
total-variation (TV), filtered variation (FV), L_1, L_2, and entropic cost
function based convex optimization problems. In this article, the PESC based
denoising and compressive sensing algorithms are developed. Simulation examples
are presented.


title: The log-term of the disc bundle over a homogeneous Hodge manifold

abstract:
  We show the vanishing of the log-term in the Fefferman expansion of the
Bergman kernel of the disk bundle over a compact simply-connected homogeneous
Kaehler--Einstein manifold of classical type.


title:
We Are Impatient: Algorithms for Geographically Distributed Load
  Balancing with (Almost) Arbitrary Load Functions

abstract:
  In geographically-distributed systems, communication latencies are
non-negligible. The perceived processing time of a request is thus composed of
the time needed to route the request to the server and the true processing
time. Once a request reaches a target server, the processing time depends on
the total load of that server; this dependency is described by a load function.
We consider a broad class of load functions; we just require that they are
convex and two times differentiable. In particular our model can be applied to
heterogeneous systems in which every server has a different load function. This
approach allows us not only to generalize results for queuing theory and for
batches of requests, but also to use empirically-derived load functions,
measured in a system under stress-testing. The optimal assignment of requests
to servers is communication-balanced, i.e. for any pair of non
perfectly-balanced servers, the reduction of processing time resulting from
moving a single request from the overloaded to underloaded server is smaller
than the additional communication latency. We present a centralized and a
decentralized algorithm for optimal load balancing. We prove bounds on the
algorithms' convergence. To the best of our knowledge these bounds were not
known even for the special cases studied previously (queuing theory and batches
of requests). Both algorithms are any-time algorithms. In the decentralized
algorithm, each server balances the load with a randomly chosen peer. Such
algorithm is very robust to failures. We prove that the decentralized algorithm
performs locally-optimal steps. Our work extends the currently known results by
considering a broad class of load functions and by establishing theoretical
bounds on the algorithms' convergence. These results are applicable for servers
whose characteristics under load cannot be described by a standard mathematical
models.


title: Artificial Noise Revisited

abstract:
  The artificial noise (AN) scheme, proposed by Goel and Negi, is being
considered as one of the key enabling technology for secure communications over
multiple-input multiple-output (MIMO) wiretap channels. However, the decrease
in secrecy rate due to the increase in the number of Eve's antennas is not well
understood. In this paper, we develop an analytical framework to characterize
the secrecy rate of the AN scheme as a function of Eve's signal-to-noise ratio
(SNR), Bob's SNR, the number of antennas in each terminal, and the power
allocation scheme. We first derive a closed-form expression for the average
secrecy rate. We then derive a closed-form expression for the asymptotic
instantaneous secrecy rate with large number of antennas at all terminals.
Finally, we derive simple lower and upper bounds on the average and
instantaneous secrecy rate that provide a tool for the system design.


title: Near-Optimally Teaching the Crowd to Classify

abstract:
  How should we present training examples to learners to teach them
classification rules? This is a natural problem when training workers for
crowdsourcing labeling tasks, and is also motivated by challenges in
data-driven online education. We propose a natural stochastic model of the
learners, modeling them as randomly switching among hypotheses based on
observed feedback. We then develop STRICT, an efficient algorithm for selecting
examples to teach to workers. Our solution greedily maximizes a submodular
surrogate objective function in order to select examples to show to the
learners. We prove that our strategy is competitive with the optimal teaching
policy. Moreover, for the special case of linear separators, we prove that an
exponential reduction in error probability can be achieved. Our experiments on
simulated workers as well as three real image annotation tasks on Amazon
Mechanical Turk show the effectiveness of our teaching algorithm.


title:
Non-homogeneous time convolutions, renewal processes and age dependent
  mean number of motorcar accidents

abstract:
  Non-homogeneous renewal processes are not yet well established. One of the
tools necessary for studying these processes is the non-homogeneous time
convolution. Renewal theory has great relevance in general in economics and in
particular in actuarial science, however most actuarial problems are connected
with the age of the insured person. The introduction of non-homogeneity in the
renewal processes brings actuarial applications closer to the real world. This
paper will define the non-homogeneous time convolutions and try to give order
to the non-homogeneous renewal processes. The numerical aspects of these
processes are dealt with and, finally, a real data application to an aspect of
motorcar insurance is proposed.


title:
On the method of pivoting the CDF for exact confidence intervals with
  illustration for exponential mean under life-test with time constraints

abstract:
  Two requirements for pivoting a cumulative distribution function (CDF) in
order to construct exact confidence intervals or bounds for a real-valued
parameter $\theta$ are the monotonicity of this CDF with respect to $\theta$
and the existence of solutions of some pertinent equations for $\theta$. The
second requirement is not fulfilled by the CDF of the maximum likelihood
estimator of the exponential scale parameter when the data come from some
life-testing scenarios such as type-I censoring, hybrid type-I censoring, and
progressive type-I censoring that are subject to time constraints. However, the
method has been used in these cases probably because the non-existence of the
solution usually happens only with small probability. Here, we illustrate the
problem by giving formal details in the case of type-I censoring and by
providing some further examples. We also present a suitable extension of the
basic pivoting method which is applicable in situations wherein the considered
equations have no solution.


title:
Evaluating functions of positive-definite matrices using colored noise
  thermostats

abstract:
  Many applications in computational science require computing the elements of
a function of a large matrix. A commonly used approach is based on the the
evaluation of the eigenvalue decomposition, a task that, in general, involves a
computing time that scales with the cube of the size of the matrix. We present
here a method that can be used to evaluate the elements of a function of a
positive-definite matrix with a scaling that is linear for sparse matrices and
quadratic in the general case. This methodology is based on the properties of
the dynamics of a multidimensional harmonic potential coupled with colored
noise generalized Langevin equation (GLE) thermostats. This "$f-$thermostat"
(FTH) approach allows us to calculate directly elements of functions of a
positive-definite matrix by carefully tailoring the properties of the
stochastic dynamics. We demonstrate the scaling and the accuracy of this
approach for both dense and sparse problems and compare the results with other
established methodologies.


title: High-Energy Neutrino Astronomy: A Glimpse of the Promised Land

abstract:
  In 2012, physicists and astronomers celebrated the hundredth anniversary of
the detection of cosmic rays by Viktor Hess. One year later, in 2013, there was
first evidence for extraterrestrial high-energy neutrinos, i.e. for signal
which may contain key information on the origin of cosmic rays. That evidence
is provided by data taken with the IceCube neutrino telescope at the South
Pole. First concepts to build a detector of this kind have been discussed at
the 1973 International Cosmic Ray Conference. Nobody would have guessed at that
time that the march towards first discoveries would take forty years, the
biblical time of the march from Egypt to Palestine. But now, after all, the
year 2013 has provided us a first glimpse to the promised land of the neutrino
universe at highest energies. This article sketches the evolution towards
detectors with a realistic discovery potential, describes the recent relevant
results obtained with the IceCube and ANTARES neutrino telescopes and tries a
look into the future.


title: Longest Common Subsequence in k-length substrings

abstract:
  In this paper we define a new problem, motivated by computational biology,
$LCSk$ aiming at finding the maximal number of $k$ length $substrings$,
matching in both input strings while preserving their order of appearance. The
traditional LCS definition is a special case of our problem, where $k = 1$. We
provide an algorithm, solving the general case in $O(n^2)$ time, where $n$ is
the length of the input strings, equaling the time required for the special
case of $k=1$. The space requirement of the algorithm is $O(kn)$. %, however,
in order to enable %backtracking of the solution, $O(n^2)$ space is needed.
  We also define a complementary $EDk$ distance measure and show that
$EDk(A,B)$ can be computed in $O(nm)$ time and $O(km)$ space, where $m$, $n$
are the lengths of the input sequences $A$ and $B$ respectively.


title:
Jacob's ladders, reverse iterations and new infinite set of
  $L_2$-orthogonal systems generated by the Riemann $\zf$-function

abstract:
  It is proved in this paper that continuum set of $L_2$-orthogonal systems
generated by the Riemann zeta-function on the critical line corresponds to
every fixed $L_2$-orthogonal system on a fixed segment. This theorem serves as
a resource for new set of integrals not accessible by the current methods in
the theory of the Riemann zeta-function.
  \noindent Dedicated to the 100th anniversary of G.H. Hardy's fundamental
theorem: the function $\zf$ has an infinite set of zeros, \cite{1}.


title: Hyperbolic predators vs parabolic preys

abstract:
  We present a nonlinear predator-prey system consisting of a nonlocal
conservation law for predators coupled with a parabolic equation for preys. The
drift term in the predators' equation is a nonlocal function of the prey
density, so that the movement of predators can be directed towards region with
high prey density. Moreover, Lotka-Volterra type right hand sides describe the
feeding. A theorem ensuring existence, uniqueness, continuous dependence of
weak solutions and various stability estimates is proved, in any space
dimension. Numerical integrations show a few qualitative features of the
solutions.


title: Small-x QCD physics probed with jets in CMS

abstract:
  The latest CMS jet measurements in p-p collisions at sqrt(s) = 7 TeV,
sensitive to small-x QCD physics, are discussed. These include inclusive
forward jet and simultaneous forward-central jet production, as well as
production ratios and azimuthal angle decorrelations of jets widely separated
in rapidity.


title:
Principal Component Analysis of Molecular Clouds: Can CO reveal the
  dynamics?

abstract:
  We use Principal Component Analysis (PCA) to study the gas dynamics in
numerical simulations of typical MCs. Our simulations account for the
non-isothermal nature of the gas and include a simplified treatment of the
time-dependent gas chemistry. We model the CO line emission in a
post-processing step using a 3D radiative transfer code. We consider mean
number densities n_0 = 30, 100, 300 cm^{-3} that span the range of values
typical for MCs in the solar neighbourhood and investigate the slope
\alpha_{PCA} of the pseudo structure function computed by PCA for several
components: the total density, H2 density, 12CO density, 12CO J = 1 -> 0
intensity and 13CO J = 1 -> 0 intensity. We estimate power-law indices
\alpha_{PCA} for different chemical species that range from 0.5 to 0.9, in good
agreement with observations, and demonstrate that optical depth effects can
influence the PCA. We show that when the PCA succeeds, the combination of
chemical inhomogeneity and radiative transfer effects can influence the
observed PCA slopes by as much as ~ +/- 0.1. The method can fail if the CO
distribution is very intermittent, e.g. in low-density clouds where CO is
confined to small fragments.


title: PTIME Computation of Transitive Closures of Octagonal Relations

abstract:
  Computing transitive closures of integer relations is the key to finding
precise invariants of integer programs. In this paper, we study difference
bounds and octagonal relations and prove that their transitive closure is a
PTIME-computable formula in the existential fragment of Presburger arithmetic.
This result marks a significant complexity improvement, as the known algorithms
have EXPTIME worst case complexity.


title: Triple trouble for XZ Tau: deep imaging with the Jansky Very Large Array

abstract:
  We present new observations of the XZ Tau system made at high angular
resolution (55 milliarcsec) with the Karl G. Jansky Very Large Array (VLA) at a
wavelength of 7 mm. Observations of XZ Tau made with the VLA in 2004 appeared
to show a triple system, with XZ Tau A resolved into two sources, XZ Tau A and
XZ Tau C. The angular separation of XZ Tau A and C (0.09 arcsec) suggested a
projected orbital separation of around 13 AU with a possible orbital period of
around 40 yr. Our observations were obtained approximately 8 yr later, a fifth
of this putative orbital period, and should therefore allow us to constrain the
orbit of XZ Tau C, and evaluate the possibility that a recent periastron
passage of C coincided with the launch of extended optical outflows from XZ Tau
A. Despite improved sensitivity and resolution compared with previous
observations, we find no evidence of XZ Tau C in our data. Components A and B
are detected with a signal-to-noise ratio greater than ten; their orbits are
consistent with previous studies, although the emission from XZ Tau A appears
to be weaker. Three possible interpretations are offered: either XZ Tau C is
transiting XZ Tau A, which is broadly consistent with the periastron passage
hypothesis, or the emission seen in 2004 was that of a transient, or XZ Tau C
does not exist. A fourth interpretation, that XZ Tau C was ejected from the
system, is dismissed due to the lack of angular momentum redistribution in the
orbits of XZ Tau A and XZ Tau B that would result from such an event. Our
observations are insufficient to distinguish between the remaining
possibilities, at least not until we obtain further VLA observations at a
sufficiently later time. A further non-detection would allow us to reject the
transit hypothesis, and the periastron passage of XZ Tau C as agent of XZ Tau
A's outflows.


title:
A population synthesis study of the luminosity function of hot white
  dwarfs

abstract:
  We present a coherent and detailed Monte Carlo simulation of the population
of hot white dwarfs. We assess the statistical significance of the hot end of
the white dwarf luminosity function and the role played by the bolometric
corrections of hydrogen-rich white dwarfs at high effective temperatures. We
use the most up-to-date stellar evolutionary models and implement a full
description of the observational selection biases to obtain realistic
simulations of the observed white dwarf population. Our theoretical results are
compared with the luminosity function of hot white dwarfs obtained from the
Sloan Digital Sky Survey (SDSS), for both DA and non-DA white dwarfs. We find
that the theoretical results are in excellent agreement with the observational
data for the population of white dwarfs with hydrogen deficient atmospheres
(non-DA white dwarfs). For the population of white dwarfs with hydrogen-rich
atmospheres (white dwarfs of the DA class), our simulations show some
discrepancies with the observations for the brightest luminosity bins. These
discrepancies can be attributed to the way in which the masses of the white
dwarfs contributing to this luminosity bin have been computed, as most of them
have masses smaller than the theoretical lower limit for carbon-oxygen white
dwarfs. We conclude that the way in which the observational luminosity function
of hot white dwarfs is obtained is very sensitive to the particular
implementation of the method used to derive the masses of the sample. We also
provide a revised luminosity function for hot white dwarfs with hydrogen-rich
atmospheres.


title: Integrability of the bi-Yang-Baxter sigma-model

abstract:
  We construct a Lax pair with spectral parameter for a two-parameter doubly
Poisson-Lie deformation of the principal chiral model.


title: Using Peano Curves to Construct Laplacians on Fractals

abstract:
  We describe a new method to construct Laplacians on fractals using a Peano
curve from the circle onto the fractal, extending an idea that has been used in
the case of certain Julia sets. The Peano curve allows us to visualize
eigenfunctions of the Laplacian by graphing the pullback to the circle. We
study in detail three fractals: the pentagasket, the octagasket and the magic
carpet. We also use the method for two nonfractal self-similar sets, the torus
and the equilateral triangle, obtaining appealing new visualizations of
eigenfunctions on the triangle. In contrast to the many familiar pictures of
approximations to standard Peano curves, that do no show self-intersections,
our descriptions of approximations to the Peano curves have self-intersections
that play a vital role in constructing graph approximations to the fractal with
explicit graph Laplacians that give the fractal Laplacian in the limit.


title: OS-Assisted Task Preemption for Hadoop

abstract:
  This work introduces a new task preemption primitive for Hadoop, that allows
tasks to be suspended and resumed exploiting existing memory management
mechanisms readily available in modern operating systems. Our technique fills
the gap that exists between the two extremes cases of killing tasks (which
waste work) or waiting for their completion (which introduces latency):
experimental results indicate superior performance and very small overheads
when compared to existing alternatives.


title: Secure Routing and Data Transmission in Mobile Ad Hoc Networks

abstract:
  In this paper, we present an identity (ID) based protocol that secures AODV
and TCP so that it can be used in dynamic and attack prone environments of
mobile ad hoc networks. The proposed protocol protects AODV using Sequential
Aggregate Signatures (SAS) based on RSA. It also generates a session key for
each pair of source-destination nodes of a MANET for securing the end-to-end
transmitted data. Here each node has an ID which is evaluated from its public
key and the messages that are sent are authenticated with a signature/ MAC. The
proposed scheme does not allow a node to change its ID throughout the network
lifetime. Thus it makes the network secure against attacks that target AODV and
TCP in MANET. We present performance analysis to validate our claim.


title: The fundamental group and torsion group of Beauville surfaces

abstract:
  We give a survey on the fundamental group of surfaces isogenous to a higher
product. If the surfaces are regular, e.g. if they are Beauville surfaces, the
first homology group is a finite group. We present a MAGMA script which
calculates the first homology groups of regular surfaces isogenous to a
product.


title:
In-network Aggregation using Efficient Routing Techniques for Event
  Driven Sensor Network

abstract:
  Sensors used in applications such as agriculture, weather, etc., monitoring
physical parameters like soil moisture, temperature, humidity, will have to
sustain their battery power for long intervals of time. In order to accomplish
this, parameter which assists in reducing the consumption of power from battery
need to be attended to. One of the factors affecting the consumption of energy
is transmit and receive power. This energy consumption can be reduced by
avoiding unnecessary transmission and reception. Efficient routing techniques
and incorporating aggregation whenever possible can save considerable amount of
energy. Aggregation reduces repeated transmission of relative values and also
reduces lot of computation at the base station. In this paper, the benefits of
aggregation over direct transmission in saving the amount of energy consumed is
discussed. Routing techniques which assist aggregation are incorporated.
Aspects like transmission of average value of sensed data around an area of the
network, minimum value in the whole of the network, triggering of event when
there is low battery are assimilated.


title: Half-quantum vortices in polar phase of superfluid He-3

abstract:
  The magnetic dipole-dipole interaction does not prevent existence of
half-quantum vortices in the polar phase of superfluid He-3 which can be stable
in uniaxial anisotropic aerogel. Here we discus this exotic possibility. After
developing a phenomenological theory of phase transition from the normal to
polar superfluid state and then to axipolar superfluid state we calculate the
NMR properties of such type superfluids at the rest or under rotation filled by
an array either single quantum or half quantum vortices.


title:
Superconductivity from repulsion in LiFeAs: novel s-wave symmetry and
  potential time-reversal symmetry breaking

abstract:
  We analyze the structure of the pairing interaction and superconducting gap
in LiFeAs by decomposing the pairing interaction for various kz cuts into s-
and d-wave components and by studying the leading superconducting
instabilities. We use the ten orbital tight-binding model, derived from
ab-initio LDA calculations with hopping parameters extracted from the fit to
ARPES experiments. We find that the pairing interaction almost decouples
between two subsets, one consists of the outer hole pocket and two electron
pockets, which are quasi-2D and are made largely out of dxy orbital, and the
other consists of the two inner hole pockets, which are quasi-3D and are made
mostly out of dxz and dyz orbitals. Furthermore, the bare inter-pocket and
intra-pocket interactions within each subset are nearly equal. In this
situation, small changes in the intra-pocket and inter-pocket interactions due
to renormalizations by high-energy fermions give rise to a variety of different
gap structures. We find four different configurations of the s-wave gap
immediately below Tc: the one in which superconducting gap changes sign between
two inner hole pockets and between the outer hole pocket and two electron
pockets, the one in which the gap changes sign between two electron pockets and
three hole pockets, the one in which the gap on the outer hole pocket differs
in sign from the gaps on the other four pockets, and the one in which the gaps
on two inner hole pockets have one sign, and the gaps on the outer hole pockets
and on electron pockets have different sign. Different s-wave gap
configurations emerge depending on whether the renormalized interactions
increase attraction within each subset or increase the coupling between
particular components of the two subsets. We argue that the state with opposite
sign of the gaps on the two inner hole pockets has the best overlap with ARPES
data.


title: The Kingman tree length process has infinite quadratic variation

abstract:
  In the case of neutral populations of fixed sizes in equilibrium whose
genealogies are described by the Kingman $N$-coalescent back from time $t$
consider the associated processes of total tree length as $t$ increases. We
show that the (c\`adl\`ag) process to which the sequence of compensated tree
length processes converges as $N$ tends to infinity is a process of infinite
quadratic variation; therefore this process cannot be a semimartingale. This
answers a question posed in Pfaffelhuber et al. (2011).


title: Ubiquitous Smart Home System Using Android Application

abstract:
  This paper presents a flexible standalone, low-cost smart home system, which
is based on the Android app communicating with the micro-web server providing
more than the switching functionalities. The Arduino Ethernet is used to
eliminate the use of a personal computer (PC) keeping the cost of the overall
system to a minimum while voice activation is incorporated for switching
functionalities. Devices such as light switches, power plugs, temperature
sensors, humidity sensors, current sensors, intrusion detection sensors,
smoke/gas sensors and sirens have been integrated in the system to demonstrate
the feasibility and effectiveness of the proposed smart home system. The smart
home app is tested and it is able to successfully perform the smart home
operations such as switching functionalities, automatic environmental control
and intrusion detection, in the later case where an email is generated and the
siren goes on.


title:
Indirect and direct signatures of Higgs portal decaying vector dark
  matter for positron excess in cosmic rays

abstract:
  We investigate the indirect signatures of the Higgs portal $U(1)_X$ vector
dark matter (VDM) $X_\mu$ from both its pair annihilation and decay. The VDM is
stable at renormalizable level by $Z_2$ symmetry, and thermalized by
Higgs-portal interactions. It can also decay by some nonrenormalizable
operators with very long lifetime at cosmological time scale. If dim-6
operators for VDM decays are suppressed by $10^{16}$ GeV scale, the lifetime of
VDM with mass $\sim$ 2 TeV is just right for explaining the positron excess in
cosmic ray recent observed by PAMELA and AMS02 Collaborations. The VDM decaying
into $\mu^+ \mu^-$ can fit the data, evading various constraints on cosmic
rays. We give one UV-complete model as an example. This scenario for Higgs
portal decaying VDM with mass around $\sim2$ TeV can be tested by DM direct
search at XENON1T and at the future colliders by measuring the Higgs
self-couplings.


title: 30 GHz monitoring of broad absorption line (BAL) quasars

abstract:
  Broad absorption line (BAL) quasars have been studied for over thirty years.
Yet it is still unclear why and when we observe broad absorption lines in
quasars. Is this phenomenon caused by geometry or is it connected with the
evolution process? Variability of the BAL quasars, if present, can give us
information about their orientation, namely it can indicate whether they are
oriented more pole-on. Using the Torun 32-metre dish equipped with the One
Centimetre Receiver Array (OCRA) we have started a monitoring campaign of a
sample of compact radio-loud BAL quasars. This 30 GHz variability monitoring
program supplements the high-resolution interferometric observations of these
objects we have carried out with the EVN and VLBA.


title: Adaptive discontinuous Galerkin methods on surfaces

abstract:
  We present a dual weighted residual-based a posteriori error estimate for a
discontinuous Galerkin (DG) approximation of a linear second-order elliptic
problem on compact smooth connected and oriented surfaces in $\mathbb{R}^{3}$
which are implicitly represented as level sets of a smooth function. We show
that the error in the energy norm may be split into a "residual part" and a
higher order "geometric part". Upper and lower bounds for the resulting a
posteriori error estimator are proven and we consider a number of challenging
test problems to demonstrate the reliability and efficiency of the estimator.
We also present a novel "geometric" driven refinement strategy for PDEs on
surfaces which considerably improves the performance of the method on complex
surfaces.


title: Characterisation of matrix entropies

abstract:
  The notion of matrix entropy was introduced by Tropp and Chen with the aim of
measuring the fluctuations of random matrices. It is a certain entropy
functional constructed from a representing function with prescribed properties,
and Tropp and Chen gave some examples. We give several abstract
characterisations of matrix entropies together with a sufficient condition in
terms of the second derivative of their representing function.


title: A Solution to the Combinatorial Puzzle of Mayer's Virial Expansion

abstract:
  Mayer's second theorem in the context of a classical gas model allows us to
write the coefficients of the virial expansion of pressure in terms of weighted
two-connected graphs. Labelle, Leroux and Ducharme studied the graph weights
arising from the one-dimensional hardcore gas model and noticed that the sum of
these weights over all two-connected graphs with $n$ vertices is $-n(n-2)!$.
This paper addresses the question of achieving a purely combinatorial proof of
this observation.


title: An asymptotic method of factorization of a class of matrix-functions

abstract:
  A novel method of asymptotic factorization of $n \times n$ matrix functions
is proposed. Considered class of matrices is motivated by certain problems
originated in the elasticity theory. An example is constructed to illustrate
effectiveness of the proposed procedure. Further applications of the method is
discussed.


title: Surface control of flexoelectricity

abstract:
  The polarization response of a material to a strain gradient, known as
flexoelectricity, holds great promise for novel electromechanical applications.
Despite considerable recent progress, however, the effect remains poorly
understood. From both the fundamental and practical viewpoints, it is of
crucial importance to know whether the coupling coefficients are primarily
governed by the properties of the bulk material or by the details of the sample
surface. Here we provide, by means of first-principles calculations,
quantitative evidence supporting the latter scenario. In particular, we
demonstrate that a SrTiO$_3$ film can yield a positive or negative
flexoelectric voltage depending on its surface termination. This result points
to a full control of the flexoelectric effect via surface/interface
engineering, opening exciting new avenues for device design.


title: Positive-entropy Hamiltonian systems on Nilmanifolds via Scattering

abstract:
  Let $\Sigma$ be a compact quotient of $T_4$, the Lie group of $4 \times 4$
upper triangular matrices with unity along the diagonal. The Lie algebra $t_4$
of $T_4$ has the standard basis $\{X_{ij}\}$ of matrices with $0$ everywhere
but in the $(i,j)$ entry, which is unity. Let $g$ be the Carnot metric, a
sub-riemannian metric, on $T_4$ for which $X_{i,i+1}$, $(i=1,2,3)$, is an
orthonormal basis. Montgomery, Shapiro and Stolin showed that the geodesic flow
of $g$ is algebraically non-integrable. This note proves that the geodesic flow
of that Carnot metric on $T \Sigma$ has positive topological entropy and is
real-analytically non-integrable. It extends earlier work by Butler and
Gelfreich.


title: On Qian's problem for $\mathcal{L}_{\infty}$-spaces

abstract:
  In this paper we devote to study Qian's problem for
$\mathcal{L}_{\infty}$-spaces. Firstly, a positive answer to Qian's problem for
$C(K)$-spaces is given by the assumption that $K$ has the C$\check{e}$ch-Stone
property. Secondly, we obtain quantitative characterizations of separably
injective spaces that turn out to give a positive answer to Qian's problem of
1995 in the setting of separable universality. Thirdly, we prove a sharpen
quantitative and generalized Sobczyk theorem, which gives sharpen constants
($\alpha,\gamma$) for Qian's Problem. Finally, we give a more generalized
Figiel theorem for $\mathcal{L}_{\infty}$-spaces.


title:
Prescribing the Gaussian curvature in a subdomain of S^2 with Neumann
  boundary condition

abstract:
  In this paper we study the problem of prescribing the Gaussian curvature
under a conformal change of the metric. We are concerned with the problem posed
on a subdomain of the 2-sphere under Neumann boundary conditions of the
conformal factor.
  If the area of the subdomain is greater than 2\pi, the associated energy
functional is no longer bounded from below. We treat this case by using min-max
techniques, giving a new existence result that generalizes and unifies previous
work on the argument.


title:
Constructing bounded remainder sets and cut-and-project sets which are
  bounded distance to lattices

abstract:
  For any irrational cut-and-project setup, we demonstrate a natural infinite
family of windows which gives rise to separated nets that are each bounded
distance to a lattice. Our proof provides a new construction, using a
sufficient condition of Rauzy, of an infinite family of non-trivial bounded
remainder sets for any totally irrational toral rotation in any dimension.


title:
Out-of-equilibrium structures in strongly interacting Rydberg gases with
  dissipation

abstract:
  The non-equilibrium dynamics of a gas of cold atoms in which Rydberg states
are off-resonantly excited is studied in the presence of noise. The interplay
between interaction and off-resonant excitation leads to an initial dynamics
where aggregates of excited Rydberg atoms slowly nucleate and grow, eventually
reaching long-lived meta-stable arrangements which then relax further on much
longer timescales. This growth dynamics is governed by an effective Master
equation which permits a transparent and largely analytical understanding of
the underlying physics. By means of extensive numerical simulations we study
the many-body dynamics and the correlations of the resulting non-equilibrium
states in various dimensions. Our results provide insight into the dynamical
richness of strongly interacting Rydberg gases in noisy environments, and
highlight the usefulness of these kind of systems for the exploration of
soft-matter-type collective behaviour.


title: Deciding Entailments in Inductive Separation Logic with Tree Automata

abstract:
  Separation Logic (SL) with inductive definitions is a natural formalism for
specifying complex recursive data structures, used in compositional
verification of programs manipulating such structures. The key ingredient of
any automated verification procedure based on SL is the decidability of the
entailment problem. In this work, we reduce the entailment problem for a
non-trivial subset of SL describing trees (and beyond) to the language
inclusion of tree automata (TA). Our reduction provides tight complexity bounds
for the problem and shows that entailment in our fragment is EXPTIME-complete.
For practical purposes, we leverage from recent advances in automata theory,
such as inclusion checking for non-deterministic TA avoiding explicit
determinization. We implemented our method and present promising preliminary
experimental results.


title: Strong Franchetta Conjecture for Linear Systems

abstract:
  In this paper, we study rational sections of the relative Picard variety of a
linear system on a smooth projective variety. Specifically, we prove that if
the linear system is basepoint-free and the locus of non-integral divisors has
codimension at least two, then all rational sections of the relative Picard
variety come from restrictions of line bundles on the variety.


title: Starobinsky-like inflation from induced gravity

abstract:
  We derive a general criterion that defines all single-field models leading to
Starobinsky-like inflation and to universal predictions for the spectral index
and tensor-to-scalar ratio, which are in agreement with Planck data. Out of all
the theories that satisfy this criterion, we single out a special class of
models with the interesting property of retaining perturbative unitarity up to
the Planck scale. These models are based on induced gravity, with the Planck
mass determined by the vacuum expectation value of the inflaton.


title: Infinite dimension of solutions for Dirichlet problem II

abstract:
  It is proved that the dimension of the space of solutions of the Dirichlet
problem for the harmonic functions in the unit disk with nontangential boundary
limits 0 a.e. is infinite.


title: On the Categorification of the M\"obius Function

abstract:
  In these notes we study several categorical generalizations of the M\"obius
function and discuss the relations between the various approaches. We emphasize
the topological and geometric meaning of these constructions.


title:
Canonical Structure of Noncommutative Quantum Mechanics as Constraint
  System

abstract:
  Starting with the first-order singular Lagrangian, the canonical structure in
the noncommutative quantum mechanics with the noncommutativities both of
coordinates and momenta is investgated. Using the projection operator method
(POM) for the constraint systems and the constraint star-product, the
noncommutative quantum system is constructed and the commutator algebra of {\it
projected} canonically conjugate set(CCS) of the system is derived in the form
including all orders of the noncommutativity parameters. We discuss the
alternative CCS, which obeys the ordinary noncommutative commutator algebra.
The {\it exact} CCS is constructed in the framework of the POM, and which is
shown to be equivalent to the CCS constructed through the Seiberg-Witten map
and the Bopp shift. We further discess the alternative Lagrangian to realize
the noncommutativities both of coordinates and momenta.


title:
Remnant mass and entropy of black holes and modified uncertainty
  principle

abstract:
  In this paper, we study the thermodynamics of black holes using a generalized
uncertainty principle (GUP) with a correction term linear order in the momentum
uncertainty. The mass-temperature relation and heat capacity are calculated
from which critical and remnant masses are obtained. The results are exact and
are found to be identical. The entropy expression gives the famous area theorem
upto leading order corrections from GUP. In particular, the linear order term
in GUP leads to a $\sqrt{A}$ correction to the area theorem. Finally, the area
theorem can be expressed in terms of a new variable termed as reduced horizon
area only when the calculation is done to the next higher order correction from
GUP.


title:
Complete Bredon cohomology and its applications to hierarchically
  defined groups

abstract:
  By considering the Bredon analogue of complete cohomology of a group, we show
that every group in the class $\LHFF$ of type Bredon-$\FP_\infty$ admits a
finite dimensional model for $\EFG$.
  We also show that abelian-by-infinite cyclic groups admit a $3$-dimensional
model for the classifying space for the family of virtually nilpotent
subgroups. This allows us to prove that for $\mF,$ the class of virtually
cyclic groups, the class of $\LHFF$-groups contains all locally virtually
soluble groups and all linear groups over $\mathbb C$ of integral
characteristic.


title: Graph classes with and without powers of bounded clique-width

abstract:
  We initiate the study of graph classes of power-bounded clique-width, that
is, graph classes for which there exist integers $k$ and $\ell$ such that the
$k$-th powers of the graphs are of clique-width at most $\ell$. We give
sufficient and necessary conditions for this property. As our main results, we
characterize graph classes of power-bounded clique-width within classes defined
by either one forbidden induced subgraph, or by two connected forbidden induced
subgraphs. We also show that for every positive integer $k$, there exists a
graph class such that the $k$-th powers of graphs in the class form a class of
bounded clique-width, while this is not the case for any smaller power.


title: Hybridization Number on Three Rooted Binary Trees is EPT

abstract:
  Phylogenetic networks are leaf-labelled directed acyclic graphs that are used
to describe non-treelike evolutionary histories and are thus a generalization
of phylogenetic trees. The hybridization number of a phylogenetic network is
the sum of all indegrees minus the number of nodes plus one. The Hybridization
Number problem takes as input a collection of phylogenetic trees and asks to
construct a phylogenetic network that contains an embedding of each of the
input trees and has a smallest possible hybridization number. We present an
algorithm for the Hybridization Number problem on three binary trees on $n$
leaves, which runs in time $O(c^k poly(n))$, with $k$ the hybridization number
of an optimal network and $c$ a constant. For two trees, an algorithm with
running time $O(3.18^k n)$ was proposed before whereas an algorithm with
running time $O(c^k poly(n))$ had prior to this article remained elusive for
more than two trees. The algorithm for two trees uses the close connection to
acyclic agreement forests to achieve a linear exponent in the running time,
while previous algorithms for more than two trees (explicitly or implicitly)
relied on a brute force search through all possible underlying network
topologies, leading to running times that are not $O(c^k poly(n))$ for any $c$.
The connection to acyclic agreement forests is much weaker for more than two
trees, so even given the right agreement forest, reconstructing the network
poses major challenges. We prove novel structural results that allow us to
reconstruct a network without having to guess the underlying topology. Our
techniques generalize to more than three input trees with the exception of one
key lemma that maps nodes in the network to tree nodes and, thus, minimizes the
amount of guessing involved in constructing the network. The main open problem
therefore is to establish a similar mapping for more than three trees.


title:
Parameterized Directed $k$-Chinese Postman Problem and $k$ Arc-Disjoint
  Cycles Problem on Euler Digraphs

abstract:
  In the Directed $k$-Chinese Postman Problem ($k$-DCPP), we are given a
connected weighted digraph $G$ and asked to find $k$ non-empty closed directed
walks covering all arcs of $G$ such that the total weight of the walks is
minimum. Gutin, Muciaccia and Yeo (Theor. Comput. Sci. 513 (2013) 124--128)
asked for the parameterized complexity of $k$-DCPP when $k$ is the parameter.
We prove that the $k$-DCPP is fixed-parameter tractable.
  We also consider a related problem of finding $k$ arc-disjoint directed
cycles in an Euler digraph, parameterized by $k$. Slivkins (ESA 2003) showed
that this problem is W[1]-hard for general digraphs. Generalizing another
result by Slivkins, we prove that the problem is fixed-parameter tractable for
Euler digraphs. The corresponding problem on vertex-disjoint cycles in Euler
digraphs remains W[1]-hard even for Euler digraphs.


title: Pion femtoscopy measurements in ALICE at the LHC

abstract:
  We present the results of two-pion Bose-Einstein correlations measured in
Pb--Pb collisions at a center-of-mass energy sqrt(s_NN) = 2.76 TeV recorded by
ALICE at the Large Hadron Collider. These types of correlations allow to
extract, using the technique of femtoscopy (also known as Hanburry-Brown Twiss
interferometry, or shortly HBT), the space-time characteristics of the source
from the correlation calculated as a function of the pair momentum difference.
The femtoscopic analysis was performed using both the Spherical Harmonics
decomposition and the standard 3D Cartesian representation of the correlation
function. The source sizes in three dimensions, the HBT radii, were extracted
by fitting the experimental correlation functions. The resulting dependencies
of the radii as a function of centrality and pair transverse momentum are
shown. The results indicate the existence of a flowing medium and provide
constraints on existing dynamical models. The ALICE Pb-Pb HBT radii are also
compared to the pp analysis and other heavy-ion experiments in order to test
the multiplicity scaling between different systems.


title:
Tuning the band gap of PbCrO4 through high-pressure: Evidence of
  wide-to-narrow semiconductor transitions

abstract:
  The electronic transport properties and optical properties of lead(II)
chromate (PbCrO4) have been studied at high pressure by means of resistivity,
Hall-effect, and optical-absorption measurements. Band-structure
first-principle calculations have been also performed. We found that the
low-pressure phase is a direct band-gap semiconductor (Eg = 2.3 eV) that shows
a high resistivity. At 3.5 GPa, associated to a structural phase transition, a
band-gap collapse takes place, becoming Eg = 1.8 eV. At the same pressure the
resistivity suddenly decreases due to an increase of the carrier concentration.
In the HP phase, PbCrO4 behaves as an n-type semiconductor, with a donor level
probably associated to the formation of oxygen vacancies. At 15 GPa a second
phase transition occurs to a phase with Eg = 1.2 eV. In this phase, the
resistivity increases as pressure does probably due to the self-compensation of
donor levels and the augmentation of the scattering of electrons with ionized
impurities. In the three phases the band gap red shifts under compression. At
20 GPa, Eg reaches a value of 0.8 eV, behaving PbCrO4 as a narrow-gap
semiconductor.


title: Distributed Vertex Cover Algorithms For Wireless Sensor Networks

abstract:
  Vertex covering has important applications for wireless sensor networks such
as monitoring link failures, facility location, clustering, and data
aggregation. In this study, we designed three algorithms for constructing
vertex cover in wireless sensor networks. The first algorithm, which is an
adaption of the Parnas & Ron's algorithm, is a greedy approach that finds a
vertex cover by using the degrees of the nodes. The second algorithm finds a
vertex cover from graph matching where Hoepman's weighted matching algorithm is
used. The third algorithm firstly forms a breadth-first search tree and then
constructs a vertex cover by selecting nodes with predefined levels from
breadth-first tree. We show the operation of the designed algorithms, analyze
them, and provide the simulation results in the TOSSIM environment. Finally we
have implemented, compared and assessed all these approaches. The transmitted
message count of the first algorithm is smallest among other algorithms where
the third algorithm has turned out to be presenting the best results in vertex
cover approximation ratio.


title:
Single- and two-qubit quantum gates using superimposed optical lattice
  potentials

abstract:
  Steps towards implementing a collision based two-qubit gate in optical
lattices have previously been realized by the parallel merging all pairs of
atoms in a periodicity two superlattice. In contrast, we propose an
architecture which allows for the merger of a selected qubit pair in a novel
long-periodicity superlattice structure consisting of two optical lattices with
close-lying periodicity. We numerically optimize the gate time and fidelity,
including the effects on neighboring atoms, and in the presence of experimental
sources of error. Furthermore, the superlattice architecture induces a
differential hyperfine shift, allowing for single-qubit gates. The fastest
possible single-qubit gate times, given a maximal tolerable rotation error on
the remaining atoms at various values of the lattice wavelengths, are
identified. We find that robust single- and two-qubit gates with gate times of
a few 100~$\mu$s and with error probabilities $\sim{}10^{-3}$ are possible.


title: Generalized Random Energy Model at Complex Temperatures

abstract:
  Motivated by the Lee--Yang approach to phase transitions, we study the
partition function of the Generalized Random Energy Model (GREM) at complex
inverse temperature $\beta$. We compute the limiting log-partition function and
describe the fluctuations of the partition function. For the GREM with $d$
levels, in total, there are $\frac 12 (d+1)(d+2)$ phases, each of which can
symbolically be encoded as $G^{d_1}F^{d_2}E^{d_3}$ with
$d_1,d_2,d_3\in\mathbb{N}_0$ such that $d_1+d_2+d_3=d$. In phase
$G^{d_1}F^{d_2}E^{d_3}$, the first $d_1$ levels (counting from the root of the
GREM tree) are in the glassy phase (G), the next $d_2$ levels are dominated by
fluctuations (F), and the last $d_3$ levels are dominated by the expectation
(E). Only the phases of the form $G^{d_1}E^{d_3}$ intersect the real $\beta$
axis. We describe the limiting distribution of the zeros of the partition
function in the complex $\beta$ plane (= Fisher zeros). It turns out that the
complex zeros densely touch the positive real axis at $d$ points at which the
GREM is known to undergo phase transitions. Our results confirm rigorously and
considerably extend the replica-method predictions from the physics literature.

categories: math.PR cond-mat.dis-nn math-ph math.CV math.MP


title: Structural Refinement for the Modal nu-Calculus

abstract:
  We introduce a new notion of structural refinement, a sound abstraction of
logical implication, for the modal nu-calculus. Using new translations between
the modal nu-calculus and disjunctive modal transition systems, we show that
these two specification formalisms are structurally equivalent.
  Using our translations, we also transfer the structural operations of
composition and quotient from disjunctive modal transition systems to the modal
nu-calculus. This shows that the modal nu-calculus supports composition and
decomposition of specifications.


title:
A Framework for Enhancing Performance and Handling Run-Time Uncertainty
  in Self-Adaptive Systems

abstract:
  Self-adaptivity allows software systems to autonomously adjust their behavior
during run-time to reduce the cost complexities caused by manual maintenance.
In this paper, a framework for building an external adaptation engine for
self-adaptive software systems is proposed. In order to improve the quality of
self-adaptive software systems, this research addresses two challenges in
self-adaptive software systems. The first challenge is to provide better
performance of the adaptation engine by managing the complexity of the
adaptation space efficiently and the second challenge is handling run-time
uncertainty that hinders the adaptation process. This research utilizes
Case-based Reasoning as an adaptation engine along with utility functions for
realizing the managed system's requirements.