title:
Thermal Conductivity Inhibition in Phonon Engineered Core-Shell
  Cross-Section Modulated Si/Ge Nanowires

abstract:
  We have shown theoretically that a combination of cross-section modulation
and acoustic mismatch in the core-shell Si/Ge nanowires can lead to a drastic
reduction of the thermal conductivity. Our calculations, which utilized two
different models - five-parameter Born-von Karman and six-parameter
valence-force field - for the lattice vibrations, indicate that the room
temperature thermal conductivity of Si/Ge cross-section modulated nanowires is
almost three orders of magnitude lower than that of bulk Si. Thermal flux in
the modulated nanowires is suppressed by an order of magnitude in comparison
with generic Si nanowires. The effect is explained by modification of the
phonon spectra in modulated nanowires leading to decrease of the phonon group
velocities and localization of certain phonon modes in narrow or wide nanowire
segments. The thermal conductivity inhibition is achieved in nanowires without
additional surface roughness and, thus, potentially reducing degradation of the
electron transport. Our results suggest that the acoustically mismatched
cross-section modulated nanowires are promising candidates for thermoelectric
applications.


title:
Electric dipole polarizabilities of doubly ionized alkaline Earth metal
  ions from perturbed relativistic coupled-cluster theory

abstract:
  Using perturbed relativistic coupled-cluster (PRCC) theory we compute the
ground state electric dipole polarizability, $\alpha$, of doubly ionized
alkaline earth metal ions $\rm{Mg}^{2+}$, $\rm{Ca}^{2+}$, $\rm{Sr}^{2+}$,
$\rm{Ba}^{2+}$ and $\rm{Ra}^{2+}$. In the present work we use the
Dirac-Coulomb-Breit atomic Hamiltonian and we also include the Uehling
potential, which is the leading order term in the vacuum polarization
corrections. We examine the correction to the orbital energies arising from the
Uehling potential in the self-consistent field calculations as well as
perturbatively. Our results of $\alpha$ are in very good agreement with the
experimental data, and we observe a change in the nature of the orbital energy
corrections arising from the vacuum polarization as we go from $\rm{Mg}^{2+}$
to Ra$^{2+}$.


title: Morpho-Kinematical Modelling of Nova Eridani 2009 (KT Eri)

abstract:
  Modelling the morphology of a nova outburst provides valuable information on
the shaping mechanism in operation at early stages following the outburst. We
performed morpho-kinematical studies, using {\sc shape}, of the evolution of
the H\alpha\ line profile following the outburst of the nova KT Eridani. We
applied a series of geometries in order to determine the morphology of the
system. The best fit morphology was that of a dumbbell structure with a ratio
between the major to minor axis of 4:1, with an inclination angle of
58$^{+6}_{-7}$ degrees and a maximum expansion velocity of 2800$\pm$200 km/s.
Although, we found that it is possible to define the overall structure of the
system, the radial density profile of the ejecta is much more difficult to
disentangle. Furthermore, morphology implied here may also be consistent with
the presence of an evolved secondary as suggested by various authors.


title: Sets in homotopy type theory

abstract:
  Homotopy Type Theory may be seen as an internal language for the
$\infty$-category of weak $\infty$-groupoids which in particular models the
univalence axiom. Voevodsky proposes this language for weak $\infty$-groupoids
as a new foundation for mathematics called the Univalent Foundations of
Mathematics. It includes the sets as weak $\infty$-groupoids with contractible
connected components, and thereby it includes (much of) the traditional set
theoretical foundations as a special case. We thus wonder whether those
`discrete' groupoids do in fact form a (predicative) topos. More generally,
homotopy type theory is conjectured to be the internal language of `elementary'
$\infty$-toposes. We prove that sets in homotopy type theory form a $\Pi
W$-pretopos. This is similar to the fact that the $0$-truncation of an
$\infty$-topos is a topos. We show that both a subobject classifier and a
$0$-object classifier are available for the type theoretical universe of sets.
However, both of these are large and moreover, the $0$-object classifier for
sets is a function between $1$-types (i.e. groupoids) rather than between sets.
Assuming an impredicative propositional resizing rule we may render the
subobject classifier small and then we actually obtain a topos of sets.


title: Arrows of time and the beginning of the universe

abstract:
  I examine two cosmological scenarios in which the thermodynamic arrow of time
points in opposite directions in the asymptotic past and future. The first
scenario, suggested by Aguirre and Gratton, assumes that the two asymptotic
regions are separated by a de Sitter-like bounce, with low-entropy boundary
conditions imposed at the bounce. Such boundary conditions naturally arise from
quantum cosmology with Hartle-Hawking wave function of the universe. The bounce
hypersurface breaks de Sitter invariance and represents the beginning of the
universe in this model. The second scenario, proposed by Carroll and Chen,
assumes some generic initial conditions on an infinite spacelike Cauchy
surface. They argue that the resulting spacetime will be non-singular, apart
from black holes that could be formed as the initial data is evolved, and will
exhibit eternal inflation in both time directions. Here I show, assuming the
null convergence condition, that the Cauchy surface in a non-singular (apart
from black holes) universe with two asymptotically inflating regions must
necessarily be compact. I also argue that the size of the universe at the
bounce between the two asymptotic regions cannot much exceed the de Sitter
horizon. The spacetime structure is then very similar to that in the
Aguirre-Gratton scenario and does require special boundary conditions at the
bounce. If cosmological singularities are allowed, then an infinite Cauchy
surface with `random' initial data will generally produce inflating regions in
both time directions. These regions, however, will be surrounded by
singularities and will have singularities in their past or future.


title:
Asymmetries of azimuthal photon distributions in non-linear Compton
  scattering in ultra-short intense laser pulses

abstract:
  Non-linear Compton scattering in ultra-short intense laser pulses is
discussed with the focus on angular distributions of the emitted photon energy.
This is an observable which is accessible easily experimentally. Asymmetries of
the azimuthal distributions are predicted for both linear and circular
polarization. We present a systematic survey of the influence of the laser
intensity, the carrier envelope phase and the laser polarization on the
emission spectra for single-cycle and few-cycle laser pulses. For linear
polarization, the dominant direction of the emission changes from a
perpendicular pattern with respect to the laser polarization at low-intensity
to a dominantly parallel emission for high-intensity laser pulses.


title: Topics in microphysics of relativistic plasmas

abstract:
  Astrophysical plasmas can have parameters vastly different from the more
studied laboratory and space plasmas. In particular, the magnetic fields can be
the dominant component of the plasma, with energy-density exceeding the
particle rest-mass energy density. Magnetic fields then determine the plasma
dynamical evolution, energy dissipation and acceleration of non-thermal
particles. Recent data coming from astrophysical high energy missions, like
magnetar bursts and Crab nebula flares, point to the importance of magnetic
reconnection in these objects.
  In this review we outline a broad spectrum of problems related to the
astrophysical relevant processes in magnetically dominated relativistic
plasmas. We discuss the problems of large scale dynamics of relativistic
plasmas, relativistic reconnection and particle acceleration at reconnecting
layers, turbulent cascade in force-fee plasmas. A number of astrophysical
applications are also discussed.


title: Nonequilibrium Ornstein-Zernike relation for Brownian many-body dynamics

abstract:
  We derive a dynamic Ornstein-Zernike equation for classical fluids undergoing
overdamped Brownian motion and driven out of equilibrium. Inhomogeneous
two-time correlation functions are obtained from functional differentiation of
the one-body density and current with respect to an appropriately chosen
external field. Functional calculus leads naturally to non-Markovian equations
of motion for the two-time correlators. Memory functions are identified as
functional derivatives of a space- and time-nonlocal power dissipation
functional. We propose an excess (over ideal gas) dissipation functional that
both generates mode-coupling theory for the two-body correlations and extends
dynamical density functional theory for the one-body fields, thus unifying the
two approaches.


title:
Dielectric Spectroscopy and Ultrasonic Study of Propylene Carbonate
  under Ultra-high Pressures

abstract:
  We present the high pressure dielectric spectroscopy (up to 4.2 GPa) and
ultrasonic study (up to 1.7 GPa) of liquid and glassy propylene carbonate (PC).
Both of the methods provide complementary pictures of the glass transition in
PC under pressure. No other relaxation processes except $\alpha$-relaxation
have been found in the studied pressure interval. The propylene carbonate
liquid is a glassformer where simple relaxation and the absence of
$\beta$-relaxation are registered in the record-breaking ranges of pressures
and densities. The equation of state of liquid PC was extended up to 1 GPa from
ultrasonic measurements of bulk modulus and is in good accordance with the
previous equations developed from volumetric data. We measured the bulk and
shear moduli and Poisson's ratio of glassy PC up to 1.7 GPa. Many relaxation
and elastic properties of PC can be qualitatively described by the soft-sphere
or Lennard-Jones model. However, for the quantitative description of entire set
of the experimental data, these models are insufficient. Moreover, the Poisson
coefficient value for glassy PC indicates a significant contribution of
non-central forces to the intermolecular potential. The well-known correlation
between Poisson's ratio and fragility index (obtained from dielectric
relaxation) is confirmed for PC at ambient pressure, but it is violated with
pressure increase. This indicates that different features of the potential
energy landscape are responsible for the evolution of dielectric response and
elasticity with pressure increase.


title:
Hydrodynamic flow in the vicinity of a nanopore induced by an applied
  voltage

abstract:
  Continuum simulation is employed to study ion transport and fluid flow
through a nanopore in a solid-state membrane under an applied potential drop.
Results show the existence of concentration polarization layers on the surfaces
of the membrane. The nonuniformity of the ionic distribution gives rise to an
electric pressure that drives vortical motion in the fluid. There is also a net
hydrodynamic flow through the nanopore due to an asymmetry induced by the
membrane surface charge. The qualitative behavior is similar to that observed
in a previous study using molecular dynamic simulations. The current--voltage
characteristics show some nonlinear features but are not greatly affected by
the hydrodynamic flow in the parameter regime studied. In the limit of thin
Debye layers, the electric resistance of the system can be characterized using
an equivalent circuit with lumped parameters. Generation of vorticity can be
understood qualitatively from elementary considerations of the Maxwell
stresses. However, the flow strength is a strongly nonlinear function of the
applied field. Combination of electrophoretic and hydrodynamic effects can lead
to ion selectivity in terms of valences and this could have some practical
applications in separations.


title: A framework for the calibration of social simulation models

abstract:
  Simulation with agent-based models is increasingly used in the study of
complex socio-technical systems and in social simulation in general. This
paradigm offers a number of attractive features, namely the possibility of
modeling emergent phenomena within large populations. As a consequence, often
the quantity in need of calibration may be a distribution over the population
whose relation with the parameters of the model is analytically intractable.
Nevertheless, we can simulate. In this paper we present a simulation-based
framework for the calibration of agent-based models with distributional output
based on indirect inference. We illustrate our method step by step on a model
of norm emergence in an online community of peer production, using data from
three large Wikipedia communities. Model fit and diagnostics are discussed.


title: Isospin breaking in the phases of the Ke4 form factors

abstract:
  Isospin breaking in the Kl4 form factors induced by the difference between
charged and neutral pion masses is studied. Starting from suitably subtracted
dispersion representations, the form factors are constructed in an iterative
way up to two loops in the low-energy expansion by implementing analyticity,
crossing, and unitarity due to two-meson intermediate states. Analytical
expressions for the phases of the two-loop form factors of the K\pm -> pi^+
pi^- e^\pm nu_e channel are given, allowing one to connect the difference of
form-factor phase shifts measured experimentally (out of the isospin limit) and
the difference of S- and P-wave pi-pi phase shifts studied theoretically (in
the isospin limit). The isospin-breaking correction consists of the sum of a
universal part, involving only pi-pi rescattering, and a process-dependent
contribution, involving the form factors in the coupled channels. The
dependence on the two S-wave scattering lengths a_0^0 and a_0^2 in the isospin
limit is worked out in a general way, in contrast to previous analyses based on
one-loop chiral perturbation theory. The latter is used only to assess the
subtraction constants involved in the dispersive approach. The two-loop
universal and process-dependent contributions are estimated and cancel
partially to yield an isospin-breaking correction close to the one-loop case.
The recent results on the phases of K^\pm -> pi^+ pi^- e^\pm nu_e form factors
obtained by the NA48/2 collaboration at the CERN SPS are reanalysed including
this isospin-breaking correction to extract values for the scattering lengths
a_0^0 and a_0^2, as well as for low-energy constants and order parameters of
two-flavour ChPT.


title:
On the exact location of the non-trivial zeros of Riemann's zeta
  function

abstract:
  In this paper we introduce the real valued real analytic function kappa(t)
implicitly defined by exp(2 pi i kappa(t)) = -exp(-2 i theta(t)) *
(zeta'(1/2-it)/zeta'(1/2+it)) and kappa(0)=-1/2. (where theta(t) is the
function appearing in the known formula zeta(1/2+it)= Z(t) * e^{-i theta(t)}).
By studying the equation kappa(t) = n (without making any unproved hypotheses),
we will show that (and how) this function is closely related to the (exact)
position of the zeros of Riemann's zeta(s) and zeta'(s). Assuming the Riemann
hypothesis and the simplicity of the zeros of zeta(s), it will follow that the
ordinate of the zero 1/2 + i gamma_n of zeta(s) will be the unique solution to
the equation kappa(t) = n.


title: Inversion polynomials for 321-avoiding permutations: addendum

abstract:
  This addendum contains results about the inversion number and major index
polynomials for permutations avoiding 321 which did not fit well into the
original paper. In particular, we consider symmetry, unimodality, behavior
modulo 2, and signed enumeration.


title: Semileptonic B / Bs decays at Belle

abstract:
  The Belle experiment at the KEKB asymmetric energy e+e- collider recorded
large data sets of both, B and Bs decays. Semileptonic decays B(s) -> X l nu (l
= electron or muon) constitute approximately one fifth of the total decay width
of B(s) mesons and play an important role in the determination of the CKM
matrix elements V_ub and V_cb. Recent results from Belle are presented,
including the study of B- -> Ds(*) K l nu, the first measurements of
semi-inclusive modes B -> D(*) X l nu and the measurement of the inclusive
branching fraction Bf(Bs -> X l nu).


title: Proton Compton scattering in a unified proton-Delta Model

abstract:
  We develop a field-theoretic model for the description of proton Compton
scattering in which the proton and its excited state, the \Delta+ resonance,
are described as part of one multiplet with a single Rarita-Schwinger
wavefunction. In order to describe the phenomena observed, it is necessary to
incorporate both minimal and non-minimal couplings. The minimal coupling
reflects the fact that the \Delta+ is a charged particle, and in this model the
minimal coupling contributes also to the M1 magnetic transition via the \gamma
N\Delta vertex. The non-minimal couplings consist of five electromagnetic
form-factors, which are accessed at fixed and vanishing momentum-transfer
squared with real photons in Compton scattering experiments, therefore it is
possible to extract a rather well-determined set of optimal parameters which
reasonably well fit the data in the resonance region 140-450 MeV. The crucial
parameter which determines the \gamma N\Delta transition amplitude and
therefore the height of the resonance peak is equal to 3.66 +- 0.03, in units
of \mu_N. We find that this parameter also primarily determines the
contributions to magnetic polarizability in this model. In the low-energy
region up to 140 MeV, we separately fit the electric and magnetic
polarizabilities, while keeping the other parameters fixed and obtain values in
line with previous approaches. The basic model is then extended by
incorporating the sigma-meson channel with the currently favored parameters,
and the pion vertex corrections.


title: Current Perpendicular-to-Plane (CPP) Magnetoresistance (MR)

abstract:
  Measurements of Giant Magnetoresistance (GMR) in ferromagnetic/non-magnetic
(F/N) multilayers with Current flow Perpendicular to the layer Planes
(CPP-geometry) can give better access to the fundamental physics underlying GMR
than measurements with the more usual Current flow In the layer Planes (CIP
geometry). Because the same measuring current passes through all of the layers,
the CPP-MR can often be described by simpler equations that allow separation of
effects of scattering within the bulk of the F- and N-metals and at F/N, N1/N2,
and F/S (S = superconductor) interfaces. We first describe the parameters that
are used to characterize the CPP-MR, the different techniques used to measure
these parameters, and the different types of multilayers used to control the
two orientations of the magnetizations of adjacent F-layers, anti-parallel (AP)
and parallel (P), that permit isolation of the parameters. We then detail what
has been learned about the parameters of bulk F-metals, of bulk N-metals, and
of F/N, N1/N2, and F/S interfaces. Especially important are the parameters of
interfaces and the spin-diffusion lengths in F-metals and F-alloys, about which
almost nothing was known in advance. Lastly, we describe work toward CPP-MR
devices and studies of magnetothermoelectric effects, before summarizing what
has been learned and listing some items not yet understood.


title:
On the periodic behavior of real-time schedulers on identical
  multiprocessor platforms

abstract:
  This paper is proposing a general periodicity result concerning any
deterministic and memoryless scheduling algorithm (including
non-work-conserving algorithms), for any context, on identical multiprocessor
platforms. By context we mean the hardware architecture (uniprocessor,
multicore), as well as task constraints like critical sections, precedence
constraints, self-suspension, etc. Since the result is based only on the
releases and deadlines, it is independent from any other parameter. Note that
we do not claim that the given interval is minimal, but it is an upper bound
for any cycle of any feasible schedule provided by any deterministic and
memoryless scheduler.


title: On small bases which admit countably many expansions

abstract:
  Let $q\in(1,2)$ and $x\in[0,\frac1{q-1}]$. We say that a sequence
$(\epsilon_i)_{i=1}^{\infty}\in\{0,1\}^{\mathbb{N}}$ is an expansion of $x$ in
base $q$ (or a $q$-expansion) if x=\sum_{i=1}^{\infty}\epsilon_iq^{-i}. Let
$\mathcal{B}_{\aleph_{0}}$ denote the set of $q$ for which there exists $x$
with exactly $\aleph_{0}$ expansions in base $q$. In \cite{EHJ} it was shown
that $\min\mathcal{B}_{\aleph_{0}}=\frac{1+\sqrt{5}}{2}.$ In this paper we show
that the smallest element of $\mathcal{B}_{\aleph_{0}}$ strictly greater than
$\frac{1+\sqrt{5}}{2}$ is $q_{\aleph_{0}}\approx1.64541$, the appropriate root
of $x^6=x^4+x^3+2x^2+x+1$. This leads to a full dichotomy for the number of
possible $q$-expansions for $q\in (\frac{1+\sqrt{5}}{2},q_{\aleph_{0}})$. We
also prove some general results regarding
$\mathcal{B}_{\aleph_{0}}\cap[\frac{1+\sqrt{5}}{2},q_{f}],$ where $q_{f}\approx
1.75488$ is the appropriate root of $x^{3}=2x^{2}-x+1.$ Moreover, the
techniques developed in this paper imply that if $x\in [0,\frac{1}{q-1}]$ has
uncountably many $q$-expansions then the set of $q$-expansions for $x$ has
cardinality equal to that of the continuum, this proves that the continuum
hypothesis holds when restricted to this specific case.


title: Singularities and the Finale of Black Hole Evaporation

abstract:
  In this essay we argue that once quantum gravitational effects change the
classical geometry of a black hole and remove the curvature singularity, the
black hole would not evaporate entirely but approach a remnant. In a modified
Schwarzschild spacetime characterized by a finite Kretschmann scalar, a minimal
mass of the black hole is naturally bounded by the existence of the horizon
rather than introduced by hand. A thermodynamical analysis discloses that the
temperature, heat capacity and the luminosity are vanishing naturally when the
black hole mass approaches the minimal value. This phenomenon may be attributed
to the existence of the minimal length in quantum gravity. It can also be
understood heuristically by connecting the generalized uncertainty principle
with the running of Newton's gravitational constant.


title:
Different routes to pressure-induced volume collapse transitions in
  gadolinium and terbium metals

abstract:
  The sudden decrease in molar volume exhibited by most lanthanides under high
pressure is often attributed to changes in the degree of localization of their
4f-electrons. We give evidence, based on electrical resistivity measurements of
dilute Y(Gd) and Y(Tb) alloys to 120 GPa, that the volume collapse transitions
in Gd and Tb metals have different origins, despite their being neighbors in
the periodic table. Remarkably, the change under pressure in the magnetic state
of isolated Pr or Tb impurity ions in the nonmagnetic Y host appears to closely
mirror corresponding changes in pure Pr or Tb metals. The collapse in Tb
appears to be driven by an enhanced negative exchange interaction between 4f
and conduction electrons under pressure (Kondo resonance) which, in the case of
Y(Tb), dramatically alters the superconducting properties of the Y host, much
like previously found for Y(Pr). In Gd our resistivity measurements suggest
that a Kondo resonance is not the main driver for its volume collapse. X-ray
absorption and emission spectroscopies clearly show that 4f local moments
remain largely intact across both volume collapse transitions ruling out 4f
band formation (delocalization) and valence transition models as possible
drivers. The results highlight the richness of behavior behind the volume
collapse transition in lanthanides and demonstrate the stability of the 4f
level against band formation to extreme pressure.


title: Analysing the Assumed Benefits of Software Requirements

abstract:
  Often during the requirements engineering (RE) process, the value of a
requirement is assessed, e.g., in requirement prioritisation, release planning,
and trade-off analysis. In order to support these activities, this research
evaluates Goal Oriented Requirements Engineering (GORE) methods for the
description of a requirement's value. Specifically, we investigate the
goal-to-goal contribution relationship for its ability to demonstrate the value
of a requirement, and propose that it is enriched with concepts such as
correlation, confidence, and utility.


title: Bounding the Higgs Boson Width Through Interferometry

abstract:
  We study the change in the di-photon invariant mass distribution for Higgs
boson decays to two photons, due to interference between the Higgs resonance in
gluon fusion and the continuum background amplitude for gluon pair to photon
pair. Previously, the apparent Higgs mass was found to shift by around 100 MeV
in the Standard Model in the leading order approximation, which may potentially
be experimentally observable. We compute the next-to-leading order QCD
corrections to the apparent mass shift, which reduce it by about 40%. The
apparent mass shift may provide a way to measure, or at least bound, the Higgs
boson width at the Large Hadron Collider through "interferometry." We
investigate how the shift depends on the Higgs width, in a model that maintains
constant Higgs boson signal yields. At Higgs widths above 30 MeV the mass shift
is over 200 MeV and increases with the square root of the width. The apparent
mass shift could be measured by comparing with the ZZ* channel, where the shift
is much smaller. It might be possible to measure the shift more accurately by
exploiting its strong dependence on the Higgs transverse momentum.


title: On the Topology of the double spherical pendulum

abstract:
  This paper studies the topology of the constant energy surfaces of the double
spherical pendulum.


title: The pre-Lie structure of the time-ordered exponential

abstract:
  The usual time-ordering operation and the corresponding time-ordered
exponential play a fundamental role in physics and applied mathematics. In this
work we study a new approach to the understanding of time-ordering relying on
recent progress made in the context of enveloping algebras of pre-Lie algebras.
Various general formulas for pre-Lie and Rota-Baxter algebras are obtained in
the process. Among others, we recover the noncommutative analog of the
classical Bohnenblust-Spitzer formula, and get explicit formulae for operator
products of time-ordered exponentials.


title:
Adaptation controls synchrony and cluster states of coupled
  threshold-model neurons: Supplemental Material

abstract:
  Derivation of the transition conditions for the variational equations for
zero-lag and cluster synchrony.


title:
The effect of rotation and tidal heating on the thermal lightcurves of
  Super Mercuries

abstract:
  Short period (<50 days) low-mass (<10Mearth) exoplanets are abundant and the
few of them whose radius and mass have been measured already reveal a diversity
in composition. Some of these exoplanets are found on eccentric orbits and are
subjected to strong tides affecting their rotation and resulting in significant
tidal heating. Within this population, some planets are likely to be depleted
in volatiles and have no atmosphere. We model the thermal emission of these
"Super Mercuries" to study the signatures of rotation and tidal dissipation on
their infrared light curve. We compute the time-dependent temperature map at
the surface and in the subsurface of the planet and the resulting
disk-integrated emission spectrum received by a distant observer for any
observation geometry. We calculate the illumination of the planetary surface
for any Keplerian orbit and rotation. We include the internal tidal heat flow,
vertical heat diffusion in the subsurface and generate synthetic light curves.
We show that the different rotation periods predicted by tidal models
(spin-orbit resonances, pseudo-synchronization) produce different photometric
signatures, which are observable provided that the thermal inertia of the
surface is high, like that of solid or melted rocks (but not regolith). Tidal
dissipation can also directly affect the light curves and make the inference of
the rotation more difficult or easier depending on the existence of hot spots
on the surface. Infrared light curve measurement with the James Webb Space
Telescope and EChO can be used to infer exoplanets' rotation periods and
dissipation rates and thus to test tidal models. This data will also constrain
the nature of the (sub)surface by constraining the thermal inertia.


title:
Quasilinear parabolic reaction-diffusion systems: user's guide to
  well-posedness, spectra and stability of travelling waves

abstract:
  This paper is concerned with quasilinear parabolic
reaction-diffusion-advection systems on extended domains. Frameworks for
well-posedness in Hilbert spaces and spaces of continuous functions are
presented, based on known results using maximal regularity. It is shown that
spectra of travelling waves on the line are meaningfully given by the familiar
tools for semilinear equations, such as dispersion relations, and basic
connections of spectra to stability and instability are considered. In
particular, a principle of linearized orbital instability for manifolds of
equilibria is proven. Our goal is to provide easy access for applicants to
these rigorous aspects. As a guiding example the Gray-Scott-Klausmeier model
for vegetation-water interaction is considered in detail.


title: Saturnian mean motion resonances in meteoroid streams

abstract:
  Many previous works have shown the relevance and dynamics of Jovian mean
motion resonances (MMR) in various meteoroid streams. These resonant swarms are
known to have produced spectacular meteor displays in the past. In this work we
investigate whether any MMR due to Saturn are feasible, and subsequently check
whether such effects are strong enough to trap meteoroids so as to cause
enhanced meteor phenomena on Earth. Extensive numerical simulations are done on
two major meteoroid streams, which are known to exhibit exterior Jovian
resonances. The roles of the 1:6 and 5:14 Jovian MMR have already been studied
in the Orionids and Leonids respectively. Now we find strong evidence of 1:3
and 8:9 Saturnian MMR in Orionids and Leonids respectively. The presence of
compact dust trails in real space due to these two Saturnian resonances is
confirmed from our calculations.


title: Pion production in the T2K experiment

abstract:
  Background: Pion production gives information on the axial form factors of
nucleon resonances. It also introduces a noticeable background to quasi-elastic
measurements on nuclear targets and thus has a significant impact on precision
studies of neutrino oscillation parameters. Purpose: To clarify
neutrino-induced pion production on nucleons and nuclei. Method: The Giessen
Boltzmann--Uehling--Uhlenbeck (GiBUU) model is used for the description of
neutrino-nucleus reactions. Results: Theoretical results for differential cross
sections for the T2K neutrino flux at the ND280 detector and integrated cross
sections as a function of neutrino energy are given. Two sets of pion
production data on elementary targets are used as inputs to obtain limits for
pion production in neutrino-nucleus reactions. Conclusions: Pion production in
the T2K ND280 detector can help to narrow down the uncertainties in the
elementary pion production cross sections. It can also give valuable
information on the nucleon-Delta axial form factor.


title:
The Multi-Layer Multi-Configuration Time-Dependent Hartree Method for
  Bosons: Theory, Implementation and Applications

abstract:
  We develop the multi-layer multi-configuration time-dependent Hartree method
for bosons (ML-MCTDHB), a variational numerically exact ab-initio method for
studying the quantum dynamics and stationary properties of bosonic systems.
ML-MCTDHB takes advantage of the permutation symmetry of identical bosons,
which allows for investigations of the quantum dynamics from few to many-body
systems. Moreover, the multi-layer feature enables ML-MCTDHB to describe mixed
bosonic systems consisting of arbitrary many species. Multi-dimensional as well
as mixed-dimensional systems can be accurately and efficiently simulated via
the multi-layer expansion scheme. We provide a detailed account of the
underlying theory and the corresponding implementation. We also demonstrate the
superior performance by applying the method to the tunneling dynamics of
bosonic ensembles in a one-dimensional double well potential, where a
single-species bosonic ensemble of various correlation strengths and a weakly
interacting two-species bosonic ensemble are considered.


title: MicroSQUIDs based on V/Cu/V Josephson nanojunctions

abstract:
  We report on the fabrication and characterization of microSQUID devices based
on nanoscale vanadium/copper/vanadium Josephson weak links. Magnetically driven
quantum interference patterns have been measured for temperatures in the 0.24 -
2 K range. As magnetometers, these devices obtain flux-to-voltage transfer
function values as high as 450 microV/Phi_0 leading to promising magnetic flux
resolution Phi_N < 3 microPhi_0 / Hz^(1/2), being here limited by the room
temperature preamplification stage. Significant improvements in the flux noise
performance figures, which are already competitive with existing
state-of-the-art commercial SQUIDs systems, are expected either with cryogenic
preamplification or with the adoption of optimized electronic readout stages
based on active feedback schemes.


title: Thermally-induced spin polarization of a two dimensional electron gas

abstract:
  Spin polarization of a two-dimensional electron gas with Rashba spin-orbit
interaction, induced by a thermo-current, is considered theoretically. It is
shown that a temperature gradient gives rise to an in-plane spin polarization
of the electron gas, which is normal to the temperature gradient. The
low-temperature spin polarization changes sign when the Fermi level crosses
bottom edge of the upper electronic subband. We also compare the results with
spin polarization induced by an external electric field (current).


title:
Time allocation in social networks: correlation between social structure
  and human communication dynamics

abstract:
  Recent research has shown the deep impact of the dynamics of human
interactions (or temporal social networks) on the spreading of information,
opinion formation, etc. In general, the bursty nature of human interactions
lowers the interaction between people to the extent that both the speed and
reach of information diffusion are diminished. Using a large database of 20
million users of mobile phone calls we show evidence this effect is not
homogeneous in the social network but in fact, there is a large correlation
between this effect and the social topological structure around a given
individual. In particular, we show that social relations of hubs in a network
are relatively weaker from the dynamical point than those that are poorer
connected in the information diffusion process. Our results show the importance
of the temporal patterns of communication when analyzing and modeling dynamical
process on social networks.


title:
Reactivity Boundaries to Separate the Fate of a Chemical Reaction
  Associated with an Index-two saddle

abstract:
  Reactivity boundaries that divide the destination and the origin of
trajectories are of crucial importance to reveal the mechanism of reactions. We
investigate whether such reactivity boundaries can be extracted for higher
index saddles in terms of a nonlinear canonical transformation successful for
index-one saddles by using a model system with an index-two saddle. It is found
that the true reactivity boundaries do not coincide with those extracted by the
transformation taking into account a nonlinearity in the region of the saddle
even for small perturbations, and the discrepancy is more pronounced for the
less repulsive direction of the index-two saddle system. The present result
indicates an importance of the global properties of the phase space to identify
the reactivity boundaries, relevant to the question of what reactant and
product are in phase space, for saddles with index more than one.


title: On the robustness of entanglement in analogue gravity systems

abstract:
  We investigate the possibility to generate quantum-correlated quasi-particles
utilizing analogue gravity systems. The quantumness of these correlations is a
key aspect of analogue gravity effects and their presence allows for a clear
separation between classical and quantum analogue gravity effects. However,
experiments in analogue systems, such as Bose-Einstein condensates, and shallow
water waves, are always conducted at non-ideal conditions, in particular, one
is dealing with dispersive media at nonzero temperatures. We analyze the
influence of the initial temperature on the entanglement generation in analogue
gravity phenomena. We lay out all the necessary steps to calculate the
entanglement generated between quasi-particle modes and we analytically derive
an upper bound on the maximal temperature at which given modes can still be
entangled. We further investigate a mechanism to enhance the quantum
correlations. As a particular example we analyze the robustness of the
entanglement creation against thermal noise in a sudden quench of an ideally
homogeneous Bose-Einstein condensate, taking into account the super-sonic
dispersion relations.


title:
Aspects of semilocal BPS vortex in systems with Lorentz symmetry
  breaking

abstract:
  It is shown the existence of a static self-dual semilocal vortex
configuration for the Maxwell-Higgs system with a Lorentz-violating CPT-even
term. The dependence of the vorticity upper limit on the Lorentz-break term is
also investigated.


title: Multicut Lower Bounds via Network Coding

abstract:
  We introduce a new technique to certify lower bounds on the multicut size
using network coding. In directed networks the network coding rate is not a
lower bound on the multicut, but we identify a class of networks on which the
rate is equal to the size of the minimum multicut and show this class is closed
under the strong graph product. We then show that the famous construction of
Saks et al. that gives a $\Theta(k)$ gap between the multicut and the
multicommodity flow rate is contained in this class. This allows us to apply
our result to strengthen their multicut lower bound, determine the exact value
of the minimum multicut, and give an optimal network coding solution with rate
matching the multicut.


title:
Soft-gluon resummation for single-particle inclusive hadroproduction at
  high transverse momentum

abstract:
  We consider the cross section for one-particle inclusive production at high
transverse momentum in hadronic collisions. We present the all-order
resummation formula that controls the logarithmically-enhanced perturbative QCD
contributions to the partonic cross section in the threshold region, at fixed
rapidity of the observed parton (hadron). The explicit resummation up to
next-to-leading logarithmic accuracy is supplemented with the computation of
the general structure of the near-threshold contributions to the
next-to-leading order cross section. This next-to-leading order computation
allows us to extract the one-loop hard-virtual amplitude that enters into the
resummation formula. This is a necessary ingredient to explicitly extend the
soft-gluon resummation beyond the next-to-leading logarithmic accuracy. These
results equally apply to both spin-unpolarized and spin-polarized scattering
processes.


title:
On a classification of Killing vector fields on a tangent bundle with
  g-natural metric

abstract:
  The tangent bundle of a Riemannian manifold (M,g) with non-degenerated
g-natural metric G that admits a Killing vector field is investigated. Using
Taylor's formula (TM,G) is decomposed into four classes that are investigated
separately. The equivalence of the existence of Killing vector field on M and
TM is proved.
  Key words: Riemannian manifold, tangent bundle, g-natural metric, Killing
vector field, non-degenerate metric.


title:
Extracting the Chern number from the dynamics of a Fermi gas:
  Implementing a quantum Hall bar for cold atoms

abstract:
  We propose a scheme to measure the quantized Hall conductivity of an
ultracold Fermi gas initially prepared in a topological (Chern) insulating
phase, and driven by a constant force. We show that the time evolution of the
center of mass, after releasing the cloud, provides a direct and clear
signature of the topologically invariant Chern number. We discuss the validity
of this scheme, highlighting the importance of driving the system with a
sufficiently strong force to displace the cloud over measurable distances while
avoiding band-mixing effects. The unusual shapes of the driven atomic cloud are
qualitatively discussed in terms of a semi-classical approach.


title: Lepton mass effects in the Bethe-Heitler process

abstract:
  We develop the full finite lepton mass formalism for the production of real
photons via the Bethe-Heitler reaction of unpolarized leptons off unpolarized
nucleons. Genuine lepton mass effects are described, in particular their
dependence upon the lepton mass and the initial beam energy, as well as their
sensitivity to the nucleon isospin. In the minimum momentum transfer region,
these effects dominate the muon induced proton cross section and become
significant for electron scattering at small $x_B$.


title: On the flexoelectric deformations of finite size bodies

abstract:
  Exact equations describing flexoelectric deformation in solids, derived
previously within the framework of a continuum media theory, are partial
differential equations of the fourth order. They are too complex to be used in
the cases interesting for applications. In this paper, using the fact of
smallness of the elastic moduli of a higher order, simplified equations are
proposed. Solution of the exact equations is approximately represented as a sum
of two parts: the first part obeys one-dimensional differential equations and
exponentially decays near surface, the second --- obeys the equations of
classical theory of elasticity. The first part can be constructed in an
explicit form. For the second part, boundary conditions are obtained. They have
a form of the classical boundary conditions for the body under external forces
on surface.


title: Pseudogap formation above the superconducting dome in iron-pnictides

abstract:
  The nature of the pseudogap in high transition temperature (high-Tc)
superconducting cuprates has been a major issue in condensed matter physics. It
is still unclear whether the high-Tc superconductivity can be universally
associated with the pseudogap formation. Here we provide direct evidence of the
existence of the pseudogap phase via angle-resolved photoemission spectroscopy
in another family of high-Tc superconductor, iron-pnictides. Our results reveal
a composition dependent pseudogap formation in the multi-band electronic
structure of BaFe2(As1-xPx)2. The pseudogap develops well above the
magnetostructural transition for low x, persists above the nonmagnetic
superconducting dome for optimal x and is destroyed for x ~ 0.6, thus showing a
notable similarity with cuprates. In addition, the pseudogap formation is
accompanied by inequivalent energy shifts in xz/yz orbitals of iron atoms,
indicative of a peculiar iron orbital ordering which breaks the four-fold
rotational symmetry.


title: Assessing the Potential of Ride-Sharing Using Mobile and Social Data

abstract:
  Ride-sharing on the daily home-work-home commute can help individuals save on
gasoline and other car-related costs, while at the same time it can reduce
traffic and pollution. This paper assesses the potential of ride-sharing for
reducing traffic in a city, based on mobility data extracted from 3G Call
Description Records (CDRs, for the cities of Barcelona and Madrid) and from
Online Social Networks (Twitter, collected for the cities of New York and Los
Angeles). We first analyze these data sets to understand mobility patterns,
home and work locations, and social ties between users. We then develop an
efficient algorithm for matching users with similar mobility patterns,
considering a range of constraints. The solution provides an upper bound to the
potential reduction of cars in a city that can be achieved by ride-sharing. We
use our framework to understand the different constraints and city
characteristics on this potential benefit. For example, our study shows that
traffic in the city of Madrid can be reduced by 59% if users are willing to
share a ride with people who live and work within 1 km; if they can only accept
a pick-up and drop-off delay up to 10 minutes, this potential benefit drops to
24%; if drivers also pick up passengers along the way, this number increases to
53%. If users are willing to ride only with people they know ("friends" in the
CDR and OSN data sets), the potential of ride-sharing becomes negligible; if
they are willing to ride with friends of friends, the potential reduction is up
to 31%.


title: The Heisenberg XX spin chain and low-energy QCD

abstract:
  By using random matrix models we uncover a connection between the low energy
sector of four dimensional QCD at finite volume and the Heisenberg XX model in
a 1d spin chain. This connection allows to relate crucial properties of QCD
with physically meaningful properties of the spin chain, establishing a
dictionary between both worlds. We predict for the spin chain a third-order
phase transition and a Tracy-Widom law in the transition region. We postulate
that this dictionary goes beyond the particular example analyzed here and can
be applied to other QFT and spin chain models. We finally comment on possible
numerical implications of the connection as well as on possible experimental
implementations.


title:
Vortices in Bose-Einstein condensates - finite-size effects and the
  thermodynamic limit

abstract:
  For a weakly-interacting Bose gas rotating in a harmonic trap we relate the
yrast states of small systems (that can be treated exactly) to the
thermodynamic limit (derived within the mean-field approximation). For a few
dozens of atoms, the yrast line shows distinct quasi-periodic oscillations with
increasing angular momentum that originate from the internal structure of the
exact many-body states. These finite-size effects disappear in the
thermodynamic limit, where the Gross-Pitaevskii approximation provides the
exact energy to leading order in the number of particles N. However, the exact
yrast states reveal significant structure not captured by the mean-field
approximation: Even in the limit of large N, the corresponding mean-field
solution accounts for only a fraction of the total weight of the exact quantum
state.


title: Persistent Homology of Delay Embeddings

abstract:
  The objective of this study is to detect and quantify the periodic behavior
of the signals using topological methods. We propose to use delay-coordinate
embeddings as a tool to measure the periodicity of signals. Moreover, we use
persistent homology for analyzing the structure of point clouds of
delay-coordinate embeddings. A method for finding the appropriate value of
delay is proposed based on the autocorrelation function of the signals. We
apply this topological approach to wheeze signals by introducing a model based
on their harmonic characteristics. Wheeze detection is performed using the
first Betti numbers of a few number of landmarks chosen from embeddings of the
signals.


title: Bandgap Engineering of Strained Monolayer and Bilayer MoS2

abstract:
  We report the influence of uniaxial tensile mechanical strain in the range
0-2.2% on the phonon spectra and bandstructures of monolayer and bilayer
molybdenum disulfide (MoS2) two-dimensional crystals. First, we employ Raman
spectroscopy to observe phonon softening with increased strain, breaking the
degeneracy in the E' Raman mode of MoS2, and extract a Gr\"uneisen parameter of
~1.06. Second, using photoluminescence spectroscopy we measure a decrease in
the optical band gap of MoS2 that is roughly linear with strain, ~45 meV%
strain for monolayer MoS2 and ~120 meV% strain for bilayer MoS2. Third, we
observe a pronounced strain-induced decrease in the photoluminescence intensity
of monolayer MoS2 that is indicative of the direct-to-indirect transition of
the character of the optical band gap of this material at applied strain of
~1.5%, a value supported by first-principles calculations that include
excitonic effects. These observations constitute the first demonstration of
strain engineering the band structure in the emergent class of two-dimensional
crystals, transition-metal dichalcogenides.


title:
Detectability of gravitational effects of supernova neutrino emission
  through pulsar timing

abstract:
  Core-collapse supernovae emit on the order of 3x10^53 ergs in high-energy
neutrinos over a time of order 10 seconds, and so decrease their mass by about
0.2 solar mass. If the explosion is nearly spherically symmetric, there will be
little gravitational wave emission. Nevertheless, the sudden decrease of mass
of the progenitor may cause a change in the gravitational time delay of signals
from a nearby pulsar. We calculate the change in arrival times as successive
pulses pass through the neutrino shell at different times, and find that the
effect may be detectable in ideal circumstances.


title:
Rule-Based Semantic Tagging. An Application Undergoing Dictionary
  Glosses

abstract:
  The project presented in this article aims to formalize criteria and
procedures in order to extract semantic information from parsed dictionary
glosses. The actual purpose of the project is the generation of a semantic
network (nearly an ontology) issued from a monolingual Italian dictionary,
through unsupervised procedures. Since the project involves rule-based Parsing,
Semantic Tagging and Word Sense Disambiguation techniques, its outcomes may
find an interest also beyond this immediate intent. The cooperation of both
syntactic and semantic features in meaning construction are investigated, and
procedures which allows a translation of syntactic dependencies in semantic
relations are discussed. The procedures that rise from this project can be
applied also to other text types than dictionary glosses, as they convert the
output of a parsing process into a semantic representation. In addition some
mechanism are sketched that may lead to a kind of procedural semantics, through
which multiple paraphrases of an given expression can be generated. Which means
that these techniques may find an application also in 'query expansion'
strategies, interesting Information Retrieval, Search Engines and Question
Answering Systems.


title: Combining Static and Dynamic Analysis for Vulnerability Detection

abstract:
  In this paper, we present a hybrid approach for buffer overflow detection in
C code. The approach makes use of static and dynamic analysis of the
application under investigation. The static part consists in calculating taint
dependency sequences (TDS) between user controlled inputs and vulnerable
statements. This process is akin to program slice of interest to calculate
tainted data- and control-flow path which exhibits the dependence between
tainted program inputs and vulnerable statements in the code. The dynamic part
consists of executing the program along TDSs to trigger the vulnerability by
generating suitable inputs. We use genetic algorithm to generate inputs. We
propose a fitness function that approximates the program behavior (control
flow) based on the frequencies of the statements along TDSs. This runtime
aspect makes the approach faster and accurate. We provide experimental results
on the Verisec benchmark to validate our approach.


title:
Swings between rotation and accretion power in a millisecond binary
  pulsar

abstract:
  It is thought that neutron stars in low-mass binary systems can accrete
matter and angular momentum from the companion star and be spun-up to
millisecond rotational periods. During the accretion stage, the system is
called a low-mass X-ray binary, and bright X-ray emission is observed. When the
rate of mass transfer decreases in the later evolutionary stages, these
binaries host a radio millisecond pulsar whose emission is powered by the
neutron star's rotating magnetic field. This evolutionary model is supported by
the detection of millisecond X-ray pulsations from several accreting neutron
stars and also by the evidence for a past accretion disc in a rotation-powered
millisecond pulsar. It has been proposed that a rotation-powered pulsar may
temporarily switch on during periods of low mass inflow in some such systems.
Only indirect evidence for this transition has hitherto been observed. Here we
report observations of accretion-powered, millisecond X-ray pulsations from a
neutron star previously seen as a rotation-powered radio pulsar. Within a few
days after a month-long X-ray outburst, radio pulses were again detected. This
not only shows the evolutionary link between accretion and rotation-powered
millisecond pulsars, but also that some systems can swing between the two
states on very short timescales.


title:
Geometric primitive feature extraction - concepts, algorithms, and
  applications

abstract:
  This thesis presents important insights and concepts related to the topic of
the extraction of geometric primitives from the edge contours of digital
images. Three specific problems related to this topic have been studied, viz.,
polygonal approximation of digital curves, tangent estimation of digital
curves, and ellipse fitting anddetection from digital curves. For the problem
of polygonal approximation, two fundamental problems have been addressed.
First, the nature of the performance evaluation metrics in relation to the
local and global fitting characteristics has been studied. Second, an explicit
error bound of the error introduced by digitizing a continuous line segment has
been derived and used to propose a generic non-heuristic parameter independent
framework which can be used in several dominant point detection methods. For
the problem of tangent estimation for digital curves, a simple method of
tangent estimation has been proposed. It is shown that the method has a
definite upper bound of the error for conic digital curves. It has been shown
that the method performs better than almost all (seventy two) existing tangent
estimation methods for conic as well as several non-conic digital curves. For
the problem of fitting ellipses on digital curves, a geometric distance
minimization model has been considered. An unconstrained, linear,
non-iterative, and numerically stable ellipse fitting method has been proposed
and it has been shown that the proposed method has better selectivity for
elliptic digital curves (high true positive and low false positive) as compared
to several other ellipse fitting methods. For the problem of detecting ellipses
in a set of digital curves, several innovative and fast pre-processing,
grouping, and hypotheses evaluation concepts applicable for digital curves have
been proposed and combined to form an ellipse detection method.


title: Physical key-protected one-time pad

abstract:
  We describe an encrypted communication principle that can form a perfectly
secure link between two parties without electronically saving either of their
keys. Instead, cryptographic key bits are kept safe within the unique
mesoscopic randomness of two volumetric scattering materials. We demonstrate
how a shared set of patterned optical probes can generate 10 gigabits of
statistically verified randomness between a pair of unique 2 cubic millimeter
scattering objects. This shared randomness is used to facilitate
information-theoretically secure communication following a modified one-time
pad protocol. Benefits of volumetric physical storage over electronic memory
include the inability to probe, duplicate or selectively reset any random bits
without fundamentally altering the entire key space. Beyond the demonstrated
communication scheme, our ability to securely couple the randomness contained
within two unique physical objects may help strengthen the hardware for a large
class of cryptographic protocols, which is currently a critically weak link in
the security pipeline of our increasingly mobile communication culture.


title:
Joint Model-Order and Step-Size Adaptation using Convex Combinations of
  Adaptive Reduced-Rank Filters

abstract:
  In this work we propose schemes for joint model-order and step-size
adaptation of reduced-rank adaptive filters. The proposed schemes employ
reduced-rank adaptive filters in parallel operating with different orders and
step sizes, which are exploited by convex combination strategies. The
reduced-rank adaptive filters used in the proposed schemes are based on a joint
and iterative decimation and interpolation (JIDF) method recently proposed. The
unique feature of the JIDF method is that it can substantially reduce the
number of coefficients for adaptation, thereby making feasible the use of
multiple reduced-rank filters in parallel. We investigate the performance of
the proposed schemes in an interference suppression application for CDMA
systems. Simulation results show that the proposed schemes can significantly
improve the performance of the existing reduced-rank adaptive filters based on
the JIDF method.


title: Unique Continuation for Stochastic Heat Equations

abstract:
  We establish a unique continuation property for stochastic heat equations
evolving in a bounded domain $G$. Our result shows that the value of the
solution can be determined uniquely by means of its value on an arbitrary open
subdomain of $G$ at any given positive time constant. Further, when $G$ is
convex and bounded, we also give a quantitative version of the unique
continuation property. As applications, we get an observability estimate for
stochastic heat equations, an approximate result and a null controllability
result for a backward stochastic heat equation.


title: Bony attractors in higher dimension

abstract:
  In this article, we extend the phenomena of a bony attractor from a rather
artificial class of step skew products to the class of diffeomorphisms on the
Cartesian product of the two-dimensional torus by a sphere of arbitrary
dimension.


title: Bounds on Surface Stress Driven Shear Flow

abstract:
  The background method is adapted to derive rigorous limits on surface speeds
and bulk energy dissipation for shear stress driven flow in two and three
dimensional channels. By-products of the analysis are nonlinear energy
stability results for plane Couette flow with a shear stress boundary
condition: when the applied stress is gauged by a dimensionless Grashoff number
$Gr$, the critical $Gr$ for energy stability is 139.5 in two dimensions, and
51.73 in three dimensions. We derive upper bounds on the friction (a.k.a.
dissipation) coefficient $C_f = \tau/\bar{u}^2$, where $\tau$ is the applied
shear stress and $\bar{u}$ is the mean velocity of the fluid at the surface,
for flows at higher $Gr$ including developed turbulence: $C_f le 1/32$ in two
dimensions and $C_f \le 1/8$ in three dimensions. This analysis rigorously
justifies previously computed numerical estimates.


title:
Kepler-77b: a very low albedo, Saturn-mass transiting planet around a
  metal-rich solar-like star

abstract:
  We report the discovery of Kepler-77b (alias KOI-127.01), a Saturn-mass
transiting planet in a 3.6-day orbit around a metal-rich solar-like star. We
combined the publicly available Kepler photometry (quarters 1-13) with
high-resolution spectroscopy from the Sandiford@McDonald and FIES@NOT
spectrographs. We derived the system parameters via a simultaneous joint fit to
the photometric and radial velocity measurements. Our analysis is based on the
Bayesian approach and is carried out by sampling the parameter posterior
distributions using a Markov chain Monte Carlo simulation. Kepler-77b is a
moderately inflated planet with a mass of Mp=0.430+/-0.032 Mjup, a radius of
Rp=0.960+/-0.016 Rjup, and a bulk density of 0.603+/-0.055 g/cm^3. It orbits a
slowly rotating (P=36+/-6 days) G5V star with M*=0.95+/-0.04 Msun,
R*=0.99+/-0.02 Rsun, Teff=5520+/-60 K, [M/H]=0.20+/-0.05, that has an age of
7.5+/-2.0 Gyr. The lack of detectable planetary occultation with a depth higher
than about 10 ppm implies a planet geometric and Bond albedo of
Ag<0.087+/-0.008 and Ab<0.058+/-0.006, respectively, placing Kepler-77b among
the gas-giant planets with the lowest albedo known so far. We found neither
additional planetary transit signals nor transit-timing variations at a level
of about 0.5 minutes, in accordance with the trend that close-in gas giant
planets seem to belong to single-planet systems. The 106 transits observed in
short-cadence mode by Kepler for nearly 1.2 years show no detectable signatures
of the planet's passage in front of starspots. We explored the implications of
the absence of detectable spot-crossing events for the inclination of the
stellar spin-axis, the sky-projected spin-orbit obliquity, and the latitude of
magnetically active regions.


title: Further exploration of top pair hadroproduction at NNLO

abstract:
  Top quark pair production is one of the cornerstones of the physics program
at hadron colliders. In this contribution, we further explore the
phenomenological implications of the recent NNLO calculation of the total
inclusive cross-section. We provide a comparison of the scale dependence of the
top pair hadroproduction cross section at different perturbative orders and
study its perturbative convergence (with and without soft-gluon resummation).
We also sketch how the NNLO top quark cross-section could be used to improve
searches of physics beyond the Standard Model.


title:
Construction of a Gauge-Invariant Action for Type II Superstring Field
  Theory

abstract:
  We construct a gauge-invariant action for covariant type II string field
theory in the NS-NS sector. Our construction is based on the large Hilbert
space description and Zwiebach's string products are used. First, we rewrite
the action for bosonic string field theory into a new form where a state in the
kernel of the generator of the gauge transformation appears explicitly. Then we
use the same strategy and write down our type II action, where a projector onto
the small Hilbert space plays an important role. We present lower-order terms
up to quartic order and show that three-point amplitudes are reproduced
correctly.


title:
How many invariant polynomials are needed to decide local unitary
  equivalence of qubit states?

abstract:
  Given L-qubit states with the fixed spectra of reduced one-qubit density
matrices, we find a formula for the minimal number of invariant polynomials
needed for solving local unitary (LU) equivalence problem, that is, problem of
deciding if two states can be connected by local unitary operations.
Interestingly, this number is not the same for every collection of the spectra.
Some spectra require less polynomials to solve LU equivalence problem than
others. The result is obtained using geometric methods, i.e. by calculating the
dimensions of reduced spaces, stemming from the symplectic reduction procedure.


title: W^{2,1} estimate for singular solutions to the Monge-Ampere equation

abstract:
  We prove an interior $W^{2,1}$ estimate for singular solutions to the
Monge-Ampere equation, and construct an example to show our results are
optimal.


title: Zeros of weakly holomorphic modular forms of level 4

abstract:
  Let $M_k^\sharp(4)$ be the space of weakly holomorphic modular forms of
weight $k$ and level $4$ that are holomorphic away from the cusp at $\infty$.
We define a canonical basis for this space and show that for almost all of the
basis elements, the majority of their zeros in a fundamental domain for
$\Gamma_0(4)$ lie on the lower boundary of the fundamental domain.
Additionally, we show that the Fourier coefficients of the basis elements
satisfy an interesting duality property.


title: False Discovery Rate Control under Archimedean Copula

abstract:
  We are considered with the false discovery rate (FDR) of the linear step-up
test $\varphi^{LSU}$ considered by Benjamini and Hochberg (1995). It is well
known that $\varphi^{LSU}$ controls the FDR at level $m_0 q / m$ if the joint
distribution of $p$-values is multivariate totally positive of order 2. In
this, $m$ denotes the total number of hypotheses, $m_0$ the number of true null
hypotheses, and $q$ the nominal FDR level. Under the assumption of an
Archimedean $p$-value copula with completely monotone generator, we derive a
sharper upper bound for the FDR of $\varphi^{LSU}$ as well as a non-trivial
lower bound. Application of the sharper upper bound to parametric subclasses of
Archimedean $p$-value copulae allows us to increase the power of
$\varphi^{LSU}$ by pre-estimating the copula parameter and adjusting $q$. Based
on the lower bound, a sufficient condition is obtained under which the FDR of
$\varphi^{LSU}$ is exactly equal to $m_0 q / m$, as in the case of
stochastically independent $p$-values. Finally, we deal with high-dimensional
multiple test problems with exchangeable test statistics by drawing a
connection between infinite sequences of exchangeable $p$-values and
Archimedean copulae with completely monotone generators. Our theoretical
results are applied to important copula families, including Clayton copulae and
Gumbel copulae.


title: The dynamics of a rotating ellipsoid

abstract:
  An interesting physical phenomenon, which contradicts our common sense, is
concerned with the dynamics of motion of a spinning ellipsoid in a non smooth
surface. A hard-boiled egg spinning on a table with a rough surface is an
example. In this article, we present a theoretical explanation, of the dynamics
of motion of this ellipsoid, that describes the axis raising phenomenon, from
the horizontal to the vertical. The equations of motion were obtained with
Lagrangian formalism.


title: Quantitative stable limit theorems on the Wiener space

abstract:
  We use Malliavin operators in order to prove quantitative stable limit
theorems on the Wiener space, where the target distribution is given by a
possibly multidimensional mixture of Gaussian distributions. Our findings
refine and generalize previous works by Nourdin and Nualart [J. Theoret.
Probab. 23 (2010) 39-64] and Harnett and Nualart [Stochastic Process. Appl. 122
(2012) 3460-3505], and provide a substantial contribution to a recent line of
research, focussing on limit theorems on the Wiener space, obtained by means of
the Malliavin calculus of variations. Applications are given to quadratic
functionals and weighted quadratic variations of a fractional Brownian motion.


title:
Coxeter-like groups for groups of set-theoretic solutions of the
  Yang--Baxter equation

abstract:
  We attach with every finite, involutive, nondegenerate set-theoretic solution
of the Yang--Baxter equation a finite group that plays for the associated
structure group the role that a finite Coxeter group plays for the associated
Artin--Tits group.


title: Diagrammatic Monte Carlo algorithm for the resonant Fermi gas

abstract:
  We provide a description of a diagrammatic Monte Carlo algorithm for the
resonant Fermi gas in the normal phase. Details are given on diagrammatic
framework, Monte Carlo moves, and incorporation of ultraviolet asymptotics.
Apart from the self-consistent bold scheme, we also describe a
non-self-consistent scheme, for which the ultraviolet treatment is more
involved.


title:
Data-driven quantification of robustness and sensitivity of cell
  signaling networks

abstract:
  Robustness and sensitivity of responses generated by cell signaling networks
has been associated with survival and evolvability of organisms. However,
existing methods analyzing robustness and sensitivity of signaling networks
ignore the experimentally observed cell-to-cell variations of protein
abundances and cell functions or contain ad hoc assumptions. We propose and
apply a data driven Maximum Entropy (MaxEnt) based method to quantify
robustness and sensitivity of Escherichia coli (E. coli) chemotaxis signaling
network. Our analysis correctly rank orders different models of E. coli
chemotaxis based on their robustness and suggests that parameters regulating
cell signaling are evolutionary selected to vary in individual cells according
to their abilities to perturb cell functions. Furthermore, predictions from our
approach regarding distribution of protein abundances and properties of
chemotactic responses in individual cells based on cell population averaged
data are in excellent agreement with their experimental counterparts. Our
approach is general and can be used to evaluate robustness as well as generate
predictions of single cell properties based on population averaged experimental
data in a wide range of cell signaling systems.


title: Semigroup identities in the monoid of triangular tropical matrices

abstract:
  We show that the submonoid of all nxn triangular tropical matrices satisfies
a nontrivial semigroup identity and provide a generic construction for classes
of such identities. The utilization of the Fibonacci number formula gives us an
upper bound on the length of these 2-variable semigroup identities.


title:
Discriminating between lepton number violating scalars using events with
  four and three charged leptons at the LHC

abstract:
  Many Standard Model extensions predict doubly-charged scalars; in particular,
all models with resonances in charged lepton-pair channels with non-vanishing
lepton number; if these are pair produced at the LHC, the observation of their
decay into $l^\pm l^\pm W^\mp W^\mp$ will be necessary in order to establish
their lepton-number violating character, which is generally not
straightforward. Nonetheless, the analysis of events containing four charged
leptons (including scalar decays into one or two taus as well as into W bosons)
makes it possible to determine whether the doubly-charged excitation belongs to
a multiplet with weak isospin T = 0, 1/2, 1, 3/2 or 2 (assuming there are no
excitations with charge > 2); though discriminating between the isosinglet and
isodoublet cases is possible only if charged-current events cannot produce the
doubly-charged isosinglet.


title: Rate-Distortion Theory for Secrecy Systems

abstract:
  Secrecy in communication systems is measured herein by the distortion that an
adversary incurs. The transmitter and receiver share secret key, which they use
to encrypt communication and ensure distortion at an adversary. A model is
considered in which an adversary not only intercepts the communication from the
transmitter to the receiver, but also potentially has side information.
Specifically, the adversary may have causal or noncausal access to a signal
that is correlated with the source sequence or the receiver's reconstruction
sequence. The main contribution is the characterization of the optimal tradeoff
among communication rate, secret key rate, distortion at the adversary, and
distortion at the legitimate receiver. It is demonstrated that causal side
information at the adversary plays a pivotal role in this tradeoff. It is also
shown that measures of secrecy based on normalized equivocation are a special
case of the framework.


title: Algebraic structures of tropical mathematics

abstract:
  Tropical mathematics often is defined over an ordered cancellative monoid
$\tM$, usually taken to be $(\RR, +)$ or $(\QQ, +)$. Although a rich theory has
arisen from this viewpoint, cf. [L1], idempotent semirings possess a restricted
algebraic structure theory, and also do not reflect certain valuation-theoretic
properties, thereby forcing researchers to rely often on combinatoric
techniques.
  In this paper we describe an alternative structure, more compatible with
valuation theory, studied by the authors over the past few years, that permits
fuller use of algebraic theory especially in understanding the underlying
tropical geometry. The idempotent max-plus algebra $A$ of an ordered monoid
$\tM$ is replaced by $R: = L\times \tM$, where $L$ is a given indexing semiring
(not necessarily with 0). In this case we say $R$ layered by $L$. When $L$ is
trivial, i.e, $L=\{1\}$, $R$ is the usual bipotent max-plus algebra. When
$L=\{1,\infty\}$ we recover the "standard" supertropical structure with its
"ghost" layer. When $L = \NN $ we can describe multiple roots of polynomials
via a "layering function" $s: R \to L$. Likewise, one can define the layering
$s: R^{(n)} \to L^{(n)}$ componentwise; vectors $v_1, \dots, v_m$ are called
tropically dependent if each component of some nontrivial linear combination
$\sum \a_i v_i$ is a ghost, for "tangible" $\a_i \in R$. Then an $n\times n$
matrix has tropically dependent rows iff its permanent is a ghost.
  We explain how supertropical algebras, and more generally layered algebras,
provide a robust algebraic foundation for tropical linear algebra, in which
many classical tools are available. In the process, we provide some new results
concerning the rank of d-independent sets (such as the fact that they are
semi-additive),put them in the context of supertropical bilinear forms, and lay
the matrix theory in the framework of identities of semirings.


title:
Generalized Beth--Uhlenbeck approach to mesons and diquarks in hot,
  dense quark matter

abstract:
  An important first step in the program of hadronization of chiral quark
models is the bosonization in meson and diquark channels. This procedure is
presented at finite temperatures and chemical potentials for the SU(2) flavor
case of the NJL model with special emphasis on the mixing between scalar meson
and scalar diquark modes which occurs in the 2SC color superconducting phase.
The thermodynamic potential is obtained in the gaussian approximation for the
meson and diquark fields and it is given the Beth-Uhlenbeck form. This allows a
detailed discussion of bound state dissociation in hot, dense matter (Mott
effect) in terms of the in-medium scattering phase shift of two-particle
correlations. It is shown for the case without meson-diquark mixing that the
phase shift can be separated into a continuum and a resonance part. In the
latter, the Mott transition manifests itself by a change of the phase shift at
threshold by \pi\ in accordance with Levinson's theorem, when a bound state
transforms to a resonance in the scattering continuum. The consequences for the
contribution of pionic correlations to the pressure are discussed by evaluating
the Beth-Uhlenbeck equation of state in different approximations. A similar
discussion is performed for the scalar diquark channel in the normal phase.
Further developments and applications of the developed approach are outlined.


title: Quantum Renormalization Group and Holography

abstract:
  Quantum renormalization group scheme provides a microscopic understanding of
holography through a general mapping between the beta functions of underlying
quantum field theories and the holographic actions in the bulk. We show that
the Einstein gravity emerges as a long wavelength holographic description for a
matrix field theory which has no other operator with finite scaling dimension
except for the energy-momentum tensor. We also point out that holographic
actions for general large N matrix field theories respect the inversion
symmetry along the radial direction in the bulk if the beta functions of
single-trace operators are gradient flows with respect to the target space
metric set by the beta functions of double-trace operators.


title: Measurement of Atmospheric Neutrino Oscillations with IceCube

abstract:
  We present the first statistically significant detection of neutrino
oscillations in the high-energy regime ($>$ 20 GeV) from an analysis of IceCube
Neutrino Observatory data collected in 2010-2011. This measurement is made
possible by the low energy threshold of the DeepCore detector ($\sim 20$ GeV)
and benefits from the use of the IceCube detector as a veto against cosmic
ray-induced muon background. The oscillation signal was detected within a
low-energy muon neutrino sample (20 -- 100 GeV) extracted from data collected
by DeepCore. A high-energy muon neutrino sample (100 GeV -- 10 TeV) was
extracted from IceCube data to constrain systematic uncertainties.
Disappearance of low-energy upward-going muon neutrinos was observed, and the
non-oscillation hypothesis is rejected with more than $5\sigma$ significance.
In a two-neutrino flavor formalism, our data are best described by the
atmospheric neutrino oscillation parameters $\Delta m^2_{23}=
(2.3^{+0.6}_{-0.5})\cdot 10^{-3}$ eV$^2$ and $\sin^2(2 \theta_{23})>0.93$, and
maximum mixing is favored.


title:
Ultrasonic beam propagation in periodic structures: verifying the
  existence of sonic crystals in triangular structures

abstract:
  When waves are propagated through a medium with scatters and these elements
are positioned periodically, as in the crystal structures, multiple scattering
leads to a phenomenon known as banded structures. This means that waves can
propagate in a certain frequency range, according to rules of dispersion, while
in other frequency ranges the propagation is cancelled. The first are called
allowed bands and the last deaf bands. This work part in order to verify the
existence of forbidden bands in the zone of ultrasonic frequency to triangular
structures formed by cylinders (hollow and solid) of different diameters (8 and
16mm.). The results indicate that the triangular structure has selective
attenuation zones, obtaining results similar to those theoretically predicted
for the two main directions of symmetry (0 and 30).


title: Inflationary phase and role of dark energy: Revisited

abstract:
  The inflationary phase of the Universe is explored by proposing a toy model
related to the scalar field, termed as {\it inflaton}. The potential part of
the energy density in the said era is assumed to have a constant vacuum energy
density part and a variable part containing the inflaton. The prime idea of the
proposed model constructed in the framework of the closed Universe is based on
a fact that the inflaton is the root cause of the orientation of the space.
According to this model the expansion of the Universe in the inflationary epoch
is not approximately rather exactly exponential in nature and thus it can solve
some of the fundamental puzzles, viz. flatness as well as horizon problems. It
is also predicted that the constant energy density part in the potential may be
associated to the dark energy, which is eventually different from the vacuum
energy, at least in the inflationary phase of the Universe. However, the model
keeps room for the end of inflationary era.


title: The entropy concept for non-equilibrium states

abstract:
  In earlier work we presented a foundation for the Second Law of Classical
Thermodynamics in terms of the Entropy Principle. More precisely, we provided
an empirically accessible axiomatic derivation of an entropy function defined
on all equilibrium states of all systems that has the appropriate additivity
and scaling properties and whose increase is a necessary and sufficient
condition for an adiabatic process between two states to be possible. Here,
after a brief review of this approach, we address the question of defining
entropy for non-equilibrium states. Our conclusion is that it is generally not
possible to find a unique entropy that has all relevant physical properties. We
do show, however, that one can define two entropy functions, called $S_-$ and
$S_+$, which, taken together, characterize the range of adiabatic processes
that can occur between non-equilibrium states. The concept of {\it
comparability} of states with respect to adiabatic changes plays an important
role in our reasoning.

categories: math-ph cond-mat.stat-mech math.MP physics.class-ph


title: Indication of anomalous heat energy production in a reactor device

abstract:
  An experimental investigation of possible anomalous heat production in a
special type of reactor tube named E-Cat HT is carried out. The reactor tube is
charged with a small amount of hydrogen loaded nickel powder plus some
additives. The reaction is primarily initiated by heat from resistor coils
inside the reactor tube. Measurement of the produced heat was performed with
high-resolution thermal imaging cameras, recording data every second from the
hot reactor tube. The measurements of electrical power input were performed
with a large bandwidth three-phase power analyzer. Data were collected in two
experimental runs lasting 96 and 116 hours, respectively. An anomalous heat
production was indicated in both experiments. The 116-hour experiment also
included a calibration of the experimental set-up without the active charge
present in the E-Cat HT. In this case, no extra heat was generated beyond the
expected heat from the electric input. Computed volumetric and gravimetric
energy densities were found to be far above those of any known chemical source.
Even by the most conservative assumptions as to the errors in the measurements,
the result is still one order of magnitude greater than conventional energy
sources.


title:
Anchors for the Cosmic Distance Scale: the Cepheid QZ Normae in the Open
  Cluster NGC 6067

abstract:
  Cepheids are key to establishing the cosmic distance scale. Therefore it's
important to assess the viability of QZ Nor, V340 Nor, and GU Nor as
calibrators for Leavitt's law via their purported membership in the open
cluster NGC 6067. The following suite of evidence confirms that QZ Nor and V340
Nor are members of NGC 6067, whereas GU Nor likely lies in the foreground: (i)
existing radial velocities for QZ Nor and V340 Nor agree with that established
for the cluster (-39.4+-1.2 km/s) to within 1 km/s, whereas GU Nor exhibits a
markedly smaller value; (ii) a steep velocity-distance gradient characterizes
the sight-line toward NGC 6067, thus implying that objects sharing common
velocities are nearly equidistant; (iii) a radial profile constructed for NGC
6067 indicates that QZ Nor is within the cluster bounds, despite being 20' from
the cluster center; (iv) new BVJH photometry for NGC 6067 confirms the cluster
lies d=1.75+-0.10 kpc distant, a result that matches Wesenheit distances
computed for QZ Nor/V340 Nor using the Benedict et al. (2007, HST parallaxes)
calibration. QZ Nor is a cluster Cepheid that should be employed as a
calibrator for the cosmic distance scale.


title:
H3+ Spectroscopy and the Ionization Rate of Molecular Hydrogen in the
  Central Few Parsecs of the Galaxy

abstract:
  We report observations and analysis of infrared spectra of H3+ and CO lines
in the Galactic center, within a few parsecs of the central black hole, Sgr A*.
We find a cosmic ray ionization rate typically an order of magnitude higher
than outside the Galactic center. Notwithstanding, the elevated cosmic ray
ionization rate is 4 orders of magnitude too short to match the proton energy
spectrum as inferred from the recent discovery of the TeV gamma-ray source in
the vicinity of Sgr A*.


title:
Timing and spectral study of the Be XRB IGR J11305-6256: Swift discovers
  the orbital period and a soft X-ray excess

abstract:
  IGR J11305-6256 is one of the numerous sources discovered through the
INTEGRAL scan of the Galactic Plane. Thanks to the Swift-BAT survey, that
allows the frequent sampling of any sky region, we have discovered in the hard
X-ray emission of this source a modulation with a period of ~120.83 d. The
significance of this periodic modulation is ~4 standard deviations in Gaussian
statistics. We interpret it as the orbital period of the binary system. We
derive an orbital separation between IGR J11305-6256 and its companion star of
~286 R$_{\odot}$ corresponding to ~19 times the radius of the companion star.
The broadband XRT-BAT (0.3-150 keV) spectrum is described either by the sum of
a black-body and a cut-off power-law or by a partially absorbed cut-off
power-law. The temporal and spectral characteristics of the source indicate its
possible association with the class of persistent, but faint, Be X-ray binary
systems.


title:
A statistical relation between the X-ray spectral index and Eddington
  ratio of active galactic nuclei in deep surveys

abstract:
  We present an investigation into how well the properties of the accretion
flow onto a supermassive black hole may be coupled to those of the overlying
hot corona. To do so, we specifically measure the characteristic spectral
index, Gamma, of a power-law energy distribution, over an energy range of 2 to
10 keV, for X-ray selected, broad-lined radio-quiet AGN up to z~2 in COSMOS and
E-CDF-S. We test the previously reported dependence between Gamma and black
hole mass, FWHM and Eddington ratio using a sample of AGN covering a broad
range in these parameters based on both the Mg ii and H-alpha emission lines
with the later afforded by recent near infrared spectroscopic observations
using Subaru/FMOS. We calculate the Eddington ratios, lambda_Edd, for sources
where a bolometric luminosity (L_Bol) has been presented in the literature,
based on SED fitting, or, for sources where these data do not exist, we
calculate L_Bol using a bolometric correction to the LX, derived from a
relationship between the bolometric correction, and LX/L3000. From a sample of
69 X-ray bright sources (>250 counts), where Gamma can be measured with
greatest precision, with an estimate of L_Bol, we find a statistically
significant correlation between Gamma and lambda_Edd, which is highly
significant with a chance probability of 6.59x10^-8. A statistically
significant correlation between Gamma and the FWHM of the optical lines is
confirmed, but at lower significance than with lambda_Edd indicating that
lambda_Edd is the key parameter driving conditions in the corona. Linear
regression analysis reveals that Gamma=(0.32+/-0.05)log10
lambda_Edd+(2.27+/-0.06) and
Gamma=(-0.69+/-0.11)log10(FWHM/km/s)+(4.44+/-0.42). Our results on
Gamma-lambda_Edd are in very good agreement with previous results. (ABRIDGED)


title: Towards a holographic theory of cosmology -- threads in a tapestry

abstract:
  In this Essay we address several fundamental issues in cosmology: What is the
nature of dark energy and dark matter? Why is the dark sector so different from
ordinary matter? Why is the effective cosmological constant non-zero but so
incredibly small? What is the reason behind the emergence of a critical
acceleration parameter of magnitude $10^{-8} cm/sec^2$ in galactic dynamics? We
suggest that the holographic principle is the linchpin in a unified scheme to
understand these various issues.


title: A Naturally Light Dilaton and a Small Cosmological Constant

abstract:
  We present a non-supersymmetric theory with a naturally light dilaton. It is
based on a 5D holographic description of a conformal theory perturbed by a
close-to-marginal operator of dimension 4-epsilon, which develops a condensate.
As long as the dimension of the perturbing operator remains very close to
marginal (even for large couplings) a stable minimum at hierarchically small
scales is achieved, where the dilaton mass squared is suppressed by epsilon. At
the same time the cosmological constant in this sector is also suppressed by
epsilon, and thus parametrically smaller than in a broken SUSY theory. As a
byproduct we also present an exact solution to the scalar-gravity system that
can be interpreted as a new holographic realization of spontaneously broken
conformal symmetry. Even though this metric deviates substantially from AdS
space in the deep IR it still describes a non-linearly realized exactly
conformal theory. We also display the effective potential for the dilaton for
arbitrary holographic backgrounds.


title:
Swift discovery of the orbital period of the HMXB IGR J015712-7259 in
  the Small Magellanic Cloud

abstract:
  In the last years the hard X-ray astronomy has made a significant step
forward, thanks to the monitoring of the IBIS/ISGRI telescope on board the
INTEGRAL satellite and of the Burst Alert Telescope (BAT) on board of the Swift
observatory. This has provided a huge amount of novel information on many
classes of sources. We have been exploiting the BAT survey data to study the
variability and the spectral properties of the new high mass X-ray binary
sources detected by INTEGRAL. In this letter we investigate the properties of
IGR J015712-7259. We perform timing analysis on the 88-month BAT survey data
and on the XRT pointed observations of this source. We also report on the
broad-band 0.2-150 keV spectral analysis. We find evidence for a modulation of
the hard-X-ray emission with period P_o=35.6 days. The significance of this
modulation is 6.1 standard deviations. The broad band spectrum is modeled with
an absorbed power law with photon index Gamma 0.4 and a steepening in the BAT
energy range modeled with a cutoff at an energy of ~13 keV.}


title: Cosmic microwave background constraints on the tensor-to-scalar ratio

abstract:
  One of the main goals of modern cosmic microwave background (CMB) missions is
to measure the tensor-to-scalar ratio $r$ accurately to constrain inflation
models. Due to ignorance about the reionization history $X_{e}(z)$, this
analysis is usually done by assuming an instantaneous reionization $X_{e}(z)$
which, however, can bias the best-fit value of $r$. Moreover, due to the strong
mixing of B-mode and E-mode polarizations in cut-sky measurements, multiplying
the sky coverage fraction $f_{sky}$ by the full-sky likelihood would not give
satisfactory results. In this work, we forecast constraints on $r$ for the
Planck mission taking into account the general reionization scenario and
cut-sky effects. Our results show that by applying an N-point interpolation
analysis to the reionization history, the bias induced by the assumption of
instantaneous reionization is removed and the value of $r$ is constrained
within $5\%$ error level, if the true value of $r$ is greater than about 0.1 .


title: On the Null Trajectories in Conformal Weyl Gravity

abstract:
  In this work we find analytical solutions to the null geodesics around a
black hole in the conformal Weyl gravity. Exact expressions for the horizons
are found, and they depend on the cosmological constant and the coupling
constants of the conformal Weyl gravity. Then, we study the radial motion from
the point of view of the proper and coordinate frames, and compare it with that
found in spacetimes of general relativity. The angular motion is also examined
qualitatively by means of an effective potential; quantitatively, the equation
of motion is solved in terms of $\wp$-Weierstrass elliptic function. Thus, we
find the deflection angle for photons without using any approximation, which is
a novel result for this kind of gravity.


title: No Firewalls in Holographic Space-Time or Matrix Theory

abstract:
  We use the formalisms of Holographic Space-time (HST) and Matrix Theory[11]
to investigate the claim of [1] that old black holes contain a firewall, i.e.
an in-falling detector encounters highly excited states at a time much shorter
than the light crossing time of the Schwarzschild radius. In both formalisms
there is no dramatic change in particle physics inside the horizon until a time
of order the Schwarzschild radius. The Matrix Theory formalism has been shown
to give rise to an S-matrix, which coincides with effective supergravity for an
infinite number of low energy amplitudes. We conclude that the firewall results
from an inappropriate use of quantum effective field theory to describe fine
details of localized events near a black hole horizon. In both HST and Matrix
Theory, the real quantum gravity Hilbert space in a localized region contains
many low energy degrees of freedom that are not captured in QU(antum)
E(ffective) F(ield) T(heory) and omits many of the high energy DOF in QUEFT.


title: 3d dualities from 4d dualities

abstract:
  Many examples of low-energy dualities have been found in supersymmetric gauge
theories with four supercharges, both in four and in three space-time
dimensions. In these dualities, two theories that are different at high
energies have the same low-energy limit. In this paper we clarify the relation
between the dualities in four and in three dimensions. We show that every four
dimensional duality gives rise to a three dimensional duality between theories
that are similar, but not identical, to the dimensional reductions of the four
dimensional dual gauge theories to three dimensions. From these specific three
dimensional dualities one can flow to many other low-energy dualities,
including known three dimensional dualities and many new ones. We discuss in
detail the case of three dimensional SU(N_c) supersymmetric QCD theories,
showing how to derive new duals for these theories from the four dimensional
duality.


title: Effective theory of chiral two-dimensional superfluids

abstract:
  We construct, to leading orders in the momentum expansion, an effective
theory of a chiral $p_x + ip_y$ two-dimensional fermionic superfluid at zero
temperature that is consistent with nonrelativistic general coordinate
invariance. This theory naturally incorporates the parity and time reversal
violating effects such as the Hall viscosity and the edge current. The particle
number current and stress tensor are computed and their linear response to
electromagnetic and gravitational sources is calculated. We also consider an
isolated vortex in a chiral superfluid and identify the leading chirality
effect in the density depletion profile.


title:
Cold fronts and metal anisotropies in the X-ray cool core of the galaxy
  cluster Zw1742+3306

abstract:
  (Context) In recent years, our understanding of the cool cores of galaxy
clusters has changed. Once thought to be relatively simple places where gas
cools and flows toward the centre, now they are believed to be very dynamic
places where heating from the central Active Galactic Nucleus (AGN) and
cooling, as inferred from active star formation, molecular gas, and Halpha
nebulosity, find an uneasy energetic balance. (Aims) We want to characterize
the X-ray properties of the nearby cool-core cluster Zw1742+3306, selected
because it is bright at X-ray (with a flux greater than 1e-11 erg/s/cm2 in the
0.1-2.4 keV band) and Halpha wavelengths (Halpha luminosity > 1e40 erg/s).
(Methods) We used Chandra data to analyze the spatial and spectral properties
of the cool core of Zw1742+3306, a galaxy cluster at z=0.0757 that emits in
Halpha and presents the brightest central galaxy located in a diffuse X-ray
emission with multiple peaks in surface brightness. (Results) We show that the
X-ray cool core of the galaxy cluster Zw1742+3306 is thermodynamically very
active with evidence of cold fronts and a weak shock in the surface brightness
map and of an apparently coherent, elongated structure with metallicity greater
than the value measured in the surrounding ambient gas by about 50 per cent.
This anisotropic structure is 280 x 90 kpc2 and is aligned with the cold fronts
and with the X-ray emission on larger scales. We suggest that all these
peculiarities in the X-ray emission of Zw1742+3306 are either a very fine-tuned
output of a sloshing gas in the cluster core or the product of a metal-rich
outflow from the central AGN.


title:
An Exactly Solvable Model for Dimension Six Higgs Operators and $h \to
  \gamma \gamma$

abstract:
  An exactly solvable large $N$ model is constructed which reduces at low
energies to the Standard Model plus the dimension six Higgs-gauge operators
$g_1^2 H^\dagger H B_{\mu \nu} B^{\mu \nu}$, $g_2^2 H^\dagger H W^a_{\mu \nu}
W^{a\mu \nu}$, $g_1 g_2 H^\dagger \tau^a H W^a_{\mu \nu} B^{\mu \nu}$, and
$\epsilon^{abc} W^a_{\mu}{}^\nu W^b_{\nu}{}^\rho W^c_{\rho}{}^\mu$. All other
dimension six operators are suppressed by powers of $1/N$. The Higgs-gauge
operators lead to deviations from the Standard Model $h \to \gamma\gamma$ and
$h \to \gamma Z$ rates. A simple variant of the model can be used to also
generate the Higgs-gluon operator $g_3^2 H^\dagger H G^A_{\mu \nu} G^{A\mu
\nu}$ which contributes to the Higgs production rate via gluon fusion.


title: First Passage Moments of Finite-State Semi-Markov Processes

abstract:
  In this paper, we discuss the computation of first passage moments of a
time-homogeneous semi-Markov process (SMP) with finite state space to certain
of its states that possess the property of universal accessibility (UA). A UA
state is one which is accessible from any other state of the SMP, but which may
or may not connect back to one or more other states. An important
characteristic of UA is that it is the state-level version of the oft-invoked
process-level property of irreducibility. We adapt existing results for
irreducible SMPs to the derivation of an analytical matrix expression for the
first passage moments to a single UA state of the SMP. In addition, consistent
estimators for these first passage moments are given.


title:
Combination of CDF and DO results on the mass of the top quark using up
  to 8.7 fb^{-1} at the Tevatron

abstract:
  We summarize the current top-quark mass measurements from the CDF and DO
experiments at Fermilab. We combine published Run I (1992--1996) measurements
with the most precise published and preliminary Run II (2001--2011)
measurements based on data sets corresponding to up to 8.7 fb^{-1} of ppbar
collisions. Taking correlations of uncertainties into account, and combining
the statistical and systematic uncertainties, the resulting preliminary
Tevatron average mass of the top quark is M_top = 173.20 \pm 0.87 GeV/c^2,
corresponding to a relative precision of 0.50 %.


title:
Gravitational and harmonic oscillator potentials on surfaces of
  revolution

abstract:
  In this paper, we consider the motion of a particle on a surface of
revolution under the influence of a central force field. We prove that there
are at most two analytic central potentials for which all the bounded,
nonsingular orbits are closed and that there are exactly two on some surfaces
with constant Gaussian curvature. The two potentials leading to closed orbits
are suitable generalizations of the gravitational and harmonic oscillator
potential. We also show that there could be surfaces admitting only one
potential that leads to closed orbits. In this case, the potential is a
generalized harmonic oscillator. In the special case of surfaces of revolution
with constant Gaussian curvature, we prove a generalization of the well-known
Bertrand theorem.