title:
Modifications to the pulsar kick velocity due to magnetic interactions
  in dense plasma

abstract:
  In this work we calculate pulsar kick velocity of magnetized neutron star
composed of degenerate quark matter core with non-Fermi liquid (NFL)
correction. Both the leading order (LO) and next to leading order (NLO)
corrections to the kick velocity have been incorporated. In addition, the NFL
corrections to the specific heat of magnetized quark matter have been
presented. This has been taken into account to calculate the kick velocity of
the neutron star. Results show significant departure from the normal Fermi
liquid estimates. The relation between radius and temperature has been shown
with kick velocity of $100\, km/s$ with and without NFL corrections.


title: Trajectory Grouping Structures

abstract:
  The collective motion of a set of moving entities like people, birds, or
other animals, is characterized by groups arising, merging, splitting, and
ending. Given the trajectories of these entities, we define and model a
structure that captures all of such changes using the Reeb graph, a concept
from topology. The trajectory grouping structure has three natural parameters
that allow more global views of the data in group size, group duration, and
entity inter-distance. We prove complexity bounds on the maximum number of
maximal groups that can be present, and give algorithms to compute the grouping
structure efficiently. We also study how the trajectory grouping structure can
be made robust, that is, how brief interruptions of groups can be disregarded
in the global structure, adding a notion of persistence to the structure.
Furthermore, we showcase the results of experiments using data generated by the
NetLogo flocking model and from the Starkey project. The Starkey data describe
the movement of elk, deer, and cattle. Although there is no ground truth for
the grouping structure in this data, the experiments show that the trajectory
grouping structure is plausible and has the desired effects when changing the
essential parameters. Our research provides the first complete study of
trajectory group evolvement, including combinatorial, algorithmic, and
experimental results.


title: On taut singularities in arbitrary characteristics

abstract:
  Over $\C$, Henry Laufer classified all taut surface singularities. We adapt
and extent his transcendental methods to positive characteristic. With this we
show that if a normal surface singularity is taut over $\C$, then the normal
surface singularities with isomorphic dual graph over algebraically closed
fields of characteristic exponent $p>1$ are taut for all but finitely many $p$.
We conjecture that this is actually "if and only if".


title: Real-Time Vector Automata

abstract:
  We study the computational power of real-time finite automata that have been
augmented with a vector of dimension k, and programmed to multiply this vector
at each step by an appropriately selected $k \times k$ matrix. Only one entry
of the vector can be tested for equality to 1 at any time. Classes of languages
recognized by deterministic, nondeterministic, and "blind" versions of these
machines are studied and compared with each other, and the associated classes
for multicounter automata, automata with multiplication, and generalized finite
automata.


title: Effects of nonstandard neutrino interactions at PINGU

abstract:
  Neutrino oscillation experiments in the past decades have greatly improved
our knowledge on neutrinos by measuring the fundamental neutrino parameters.
The ongoing and upcoming neutrino oscillation experiments are intended to pin
down the neutrino mass hierarchy and to discover the leptonic CP violation. By
means of neutrino oscillograms, we analyze the impact of non-standard neutrino
interactions on neutrino oscillations in the Earth matter. The standard
neutrino oscillation probabilities may be significantly changed by non-standard
interaction parameters, and in particular, the CP-violating effects in the
energy range E = 1 ~ 20 GeV are greatly enhanced. In addition, the event rates
of muon neutrinos in the proposed huge atmospheric neutrino experiment, PINGU
at the South Pole, have been estimated in the presence of non-standard neutrino
interactions. It has been found that the PINGU experiment has very good
sensitivities to the non-standard neutrino interaction parameters.


title: The Hopkins Ultraviolet Telescope: The Final Archive

abstract:
  The Hopkins Ultraviolet Telescope (HUT) was a 0.9 m telescope and
moderate-resolution (~3 A) far-ultraviolet (820-1850 A) spectrograph that flew
twice on the space shuttle, in 1990 December (Astro-1, STS-35) and 1995 March
(Astro-2, STS-67). The resulting spectra were originally archived in a
non-standard format that lacked important descriptive metadata. To increase
their utility, we have modified the original data-reduction software to produce
a new and more user-friendly data product, a time-tagged photon list similar in
format to the Intermediate Data Files (IDFs) produced by the {\it Far
Ultraviolet Spectroscopic Explorer} calibration pipeline. We have transferred
all relevant pointing and instrument-status information from locally-archived
science and engineering databases into new FITS header keywords for each data
set. Using this new pipeline, we have reprocessed the entire HUT archive from
both missions, producing a new set of calibrated spectral products in a modern
FITS format that is fully compliant with Virtual Observatory requirements. For
each exposure, we have generated quick-look plots of the fully-calibrated
spectrum and associated pointing history information. Finally, we have
retrieved from our archives HUT TV guider images, which provide information on
aperture positioning relative to guide stars, and converted them into
FITS-format image files. All of these new data products are available in the
new HUT section of the Mikulski Archive for Space Telescopes (MAST), along with
historical and reference documents from both missions. In this paper, we
document the improved data-processing steps applied to the data and show
examples of the new data products.


title: Torsion homology of arithmetic lattices and K2 of imaginary fields

abstract:
  We study upper bounds for the torsion in homology of nonuniform arithmetic
lattices. Together with recent results of Calegari-Venkatesh, this can be used
to obtain upper bounds on K2 of the ring of integers of totally imaginary
fields.


title:
Design and operation of a microfabricated phonon spectrometer utilizing
  superconducting tunnel junctions as phonon transducers

abstract:
  In order to fully understand nanoscale heat transport it is necessary to
spectrally characterize phonon transmission in nanostructures. Towards this
goal we have developed a microfabricated phonon spectrometer. We utilize
microfabricated superconducting tunnel junction-based (STJ) phonon transducers
for the emission and detection of tunable, non-thermal, and spectrally resolved
acoustic phonons, with frequencies ranging from ~100 to ~870 GHz, in silicon
microstructures. We show that phonon spectroscopy with STJs offers a spectral
resolution of ~15-20 GHz, which is ~20 times better than thermal conductance
measurements, for probing nanoscale phonon transport. The STJs are Al-AlxOy-Al
tunnel junctions and phonon emission and detection occurs via quasiparticle
excitation and decay transitions that occur in the superconducting films. We
elaborate on the design geometry and constraints of the spectrometer, the
fabrication techniques, and the low-noise instrumentation that are essential
for successful application of this technique for nanoscale phonon studies. We
discuss the spectral distribution of phonons emitted by an STJ emitter and the
efficiency of their detection by an STJ detector. We demonstrate that the
phonons propagate ballistically through a silicon microstructure, and that
submicron spatial resolution is realizable in a design such as ours. Spectrally
resolved measurements of phonon transport in nanoscale structures and
nanomaterials will further the engineering and exploitation of phonons, and
thus have important ramifications for nanoscale thermal transport as well as
the burgeoning field of nanophononics.


title:
Finite-dimensional irreducible $U_q(\mathfrak{sl}_2)$-modules from the
  equitable point of view

abstract:
  We consider the quantum algebra $U_q(\mathfrak{sl}_2)$ with $q$ not a root of
unity. We describe the finite-dimensional irreducible
$U_q(\mathfrak{sl}_2)$-modules from the point of view of the equitable
presentation.


title:
Model-Based Calibration of Filter Imperfections in the Random
  Demodulator for Compressive Sensing

abstract:
  The random demodulator is a recent compressive sensing architecture providing
efficient sub-Nyquist sampling of sparse band-limited signals. The compressive
sensing paradigm requires an accurate model of the analog front-end to enable
correct signal reconstruction in the digital domain. In practice, hardware
devices such as filters deviate from their desired design behavior due to
component variations. Existing reconstruction algorithms are sensitive to such
deviations, which fall into the more general category of measurement matrix
perturbations. This paper proposes a model-based technique that aims to
calibrate filter model mismatches to facilitate improved signal reconstruction
quality. The mismatch is considered to be an additive error in the discretized
impulse response. We identify the error by sampling a known calibrating signal,
enabling least-squares estimation of the impulse response error. The error
estimate and the known system model are used to calibrate the measurement
matrix. Numerical analysis demonstrates the effectiveness of the calibration
method even for highly deviating low-pass filter responses. The proposed method
performance is also compared to a state of the art method based on discrete
Fourier transform trigonometric interpolation.


title:
Measurement of the cross section for direct-photon production in
  association with a heavy quark in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96
  TeV

abstract:
  We report on a measurement of the cross section for direct-photon production
in association with a heavy quark using the full data set of $\sqrt{s}=1.96$
TeV proton-antiproton collisions corresponding to 9.1 fb$^{-1}$ of integrated
luminosity collected by the CDF II detector at the Fermilab Tevatron. The
measurements are performed as a function of the photon transverse momentum,
covering photon transverse momentum between 30 and 300 GeV, photon rapidities
$|y^{\gamma}|<1.0$, heavy-quark-jet transverse momentum $p_{T}^{jet}>20$ GeV,
and jet rapidities $|y^{jet}|<1.5$. The results are compared with several
theoretical predictions.


title: Einstein locally conformal calibrated $G_2$-structures

abstract:
  We study locally conformal calibrated $G_2$-structures whose underlying
Riemannian metric is Einstein, showing that in the compact case the scalar
curvature cannot be positive. As a consequence, a compact homogeneous
$7$-manifold cannot admit an invariant Einstein locally conformal calibrated
$G_2$-structure unless the underlying metric is flat. In contrast to the
compact case, we provide a non-compact example of homogeneous manifold endowed
with a locally conformal calibrated $G_2$-structure whose associated Riemannian
metric is Einstein and non Ricci-flat. The homogeneous Einstein metric is a
rank-one extension of a Ricci soliton on the $3$-dimensional complex Heisenberg
group endowed with a left-invariant coupled ${\rm SU}(3)$-structure $(\omega,
\Psi)$, i.e., such that $d \omega = c {\rm Re}(\Psi)$, with $c \in \mathbb{R} -
\{ 0 \}$. Nilpotent Lie algebras admitting a coupled ${\rm SU}(3)$-structure
are also classified.


title: About the survey of propagandistic messages in contemporary social media

abstract:
  This paper presents the research results that have identified a set of
characteristic parameters of propagandistic messages. Later these parameters
can be used in the algorithm creating special user-oriented propagandistic
messages to improve distribution and assimilation of information by users.


title: Uniqueness of positive periodic solutions with some peaks

abstract:
  This work deals with the semi linear equation $-\Delta u+u-u^p=0$ in $\R^N$,
$2\leq p<{N+2\over N-2}$. We consider the positive solutions which are
${2\pi\over\ep}$-periodic in $x_1$ and decreasing to 0 in the other variables,
uniformly in $x_1$. Let a periodic configuration of points be given on the
$x_1$-axis, which repel each other as the period tends to infinity. If there
exists a solution which has these points as peaks, we prove that the points
must be asymptotically uniformly distributed on the $x_1$-axis. Then, for $\ep$
small enough, we prove the uniqueness up to a translation of the positive
solution with some peaks on the $x_1$-axis, for a given minimal period in
$x_1$.


title:
Stability of isotropic steady states for the relativistic Vlasov-Poisson
  system

abstract:
  ?In this work, we study the orbital stability of stationary solutions to the
relativistic Vlasov-Manev system. This system is a kinetic model describing the
evolution of a stellar system subject to its own gravity with some relativistic
corrections. For this system, the orbital stability was proved for isotropic
models constructed as minimizers of the Hamiltonian under a subcritical
condition. We obtain here this stability for all isotropic models by a
non-variationnal approach. We use here a new method developed in [23] for the
classical Vlasov-Poisson system. We derive the stability from the monotonicity
of the Hamiltonian under suitable generalized symmetric rearrangements and from
a Antonov type coer- civity property. We overcome here two new difficulties :
the first one is the a priori non-continuity of the potentials, from which a
greater control of the re- arrangements is necessary. The second difficulty is
related to the homogeneity breaking which does not give the boundedness of the
kinetic energy. Indeed, in this paper, we does not suppose any subcritical
condition satisfied by the steady states.


title: On the inequalities of Babu\v{s}ka-Aziz, Friedrichs and Horgan-Payne

abstract:
  The equivalence between the inequalities of Babu\v{s}ka-Aziz and Friedrichs
for sufficiently smooth bounded domains in the plane has been shown by Horgan
and Payne 30 years ago. We prove that this equivalence, and the equality
between the associated constants, is true without any regularity condition on
the domain. For the Horgan-Payne inequality, which is an upper bound of the
Friedrichs constant for plane star-shaped domains in terms of a geometric
quantity known as the Horgan-Payne angle, we show that it is true for some
classes of domains, but not for all bounded star-shaped domains. We prove a
weaker inequality that is true in all cases.


title:
Measurement of R = \boldmath${\mathcal{B}(t \rightarrow
  Wb)/\mathcal{B}(t \rightarrow Wq)} $ in Top--quark--pair Decays using
  Lepton+jets Events and the Full CDF Run II Data set

abstract:
  We present a measurement of the ratio of the top-quark branching fractions
$R=\mathcal{B}(t\rightarrow Wb)/\mathcal{B}(t\rightarrow Wq)$, where $q$
represents quarks of type
  $b$, $s$, or $d$, in the final state with a lepton and hadronic jets. The
measurement uses $\sqrt{s}$ = 1.96 TeV proton--antiproton collision data from
8.7 fb$^{-1}$ of integrated luminosity collected with the Collider Detector at
Fermilab during Run II of the Tevatron. We simultaneously measure $R=0.94 \pm
0.09$ (stat+syst), the $t\bar{t}$ production cross section $\sigma_{t \bar t} =
7.5 \pm 1.0$ (stat+syst) pb. The magnitude of the Cabibbo-Kobayashi-Maskawa
matrix element, $|V_{tb}| = 0.97 \pm 0.05$ (stat+syst) is extracted assuming
three generations of quarks, and a lower limit of $|V_{tb}|>0.89$ at 95%
credibility level is set.


title:
Hamiltonian description of self-consistent wave-particle dynamics in a
  periodic structure

abstract:
  Conservation of energy and momentum in the classical theory of radiating
electrons has been a challenging problem since its inception. We propose a
formulation of classical electrodynamics in Hamiltonian form that satisfies the
Maxwell equations and the Lorentz force. The radiated field is represented with
eigenfunctions using the Gel'fand $\beta$-transform. The electron Hamiltonian
is the standard one coupling the particles with the propagating fields. The
dynamics conserves energy and excludes self-acceleration. A complete
Hamiltonian formulation results from adding electrostatic action-at-a-distance
coupling between electrons.


title:
A Spitzer Study of Pseudobulges in S0 Galaxies : Secular Evolution of
  Disks

abstract:
  In this Letter, we present a systematic study of lenticular (S0) galaxies
based on mid-infrared imaging data on 185 objects taken using the Spitzer Infra
Red Array Camera. We identify the S0s hosting pseudobulges based on the
position of the bulge on the Kormendy diagram and the S\'{e}rsic index of the
bulge. We find that pseudobulges preferentially occur in the fainter luminosity
class (defined as having total K-band absolute magnitude M_K fainter than
-22.66 in the AB system). We present relations between bulge and disk
parameters obtained as a function of the bulge type. The disks in the
pseudobulge hosting galaxies are found to have distinct trends on the r_e-r_d
and \mu_d (0) - r_d correlations compared to those in galaxies with classical
bulges. We show that the disks of pseudobulge hosts possess on average a
smaller scale length and have a fainter central surface brightness than their
counterparts occurring in classical bulge hosting galaxies. The differences
found for discs in pseudobulge and classical bulge hosting galaxies may be a
consequence of the different processes creating the central mass
concentrations.


title:
Particles Prefer Walking Along the Axes: Experimental Insights into the
  Behavior of a Particle Swarm

abstract:
  Particle swarm optimization (PSO) is a widely used nature-inspired
meta-heuristic for solving continuous optimization problems. However, when
running the PSO algorithm, one encounters the phenomenon of so-called
stagnation, that means in our context, the whole swarm starts to converge to a
solution that is not (even a local) optimum. The goal of this work is to point
out possible reasons why the swarm stagnates at these non-optimal points. To
achieve our results, we use the newly defined potential of a swarm. The total
potential has a portion for every dimension of the search space, and it drops
when the swarm approaches the point of convergence. As it turns out
experimentally, the swarm is very likely to come sometimes into "unbalanced"
states, i. e., almost all potential belongs to one axis. Therefore, the swarm
becomes blind for improvements still possible in any other direction. Finally,
we show how in the light of the potential and these observations, a slightly
adapted PSO rebalances the potential and therefore increases the quality of the
solution.


title:
Estimating the quadratic covariation matrix from noisy observations:
  Local method of moments and efficiency

abstract:
  An efficient estimator is constructed for the quadratic covariation or
integrated co-volatility matrix of a multivariate continuous martingale based
on noisy and nonsynchronous observations under high-frequency asymptotics. Our
approach relies on an asymptotically equivalent continuous-time observation
model where a local generalised method of moments in the spectral domain turns
out to be optimal. Asymptotic semi-parametric efficiency is established in the
Cram\'{e}r-Rao sense. Main findings are that nonsynchronicity of observation
times has no impact on the asymptotics and that major efficiency gains are
possible under correlation. Simulations illustrate the finite-sample behaviour.


title:
Line-of-sight geometrical and instrumental resolution effects on
  intensity perturbations by sausage modes

abstract:
  Diagnostics of MHD waves in the solar atmosphere is a topic which often
encounters problems of interpretation, due partly to the high complexity of the
solar atmospheric medium. Forward modeling can significantly guide
interpretation, bridging the gap between numerical simulations and
observations, and increasing the reliability of mode identification for
application of MHD seismology. In this work we aim at determining the
characteristics of the fast MHD sausage mode in the corona on the modulation of
observable quantities such as line intensity and spectral line broadening.
Effects of line-of-sight angle, and spatial, temporal and spectral resolutions
are considered. We take a cylindrical tube simulating a loop in a low-{\beta}
coronal environment with an optically thin background, and let it oscillate
with the fast sausage mode. A parametric study is performed. Among other
results, we show that regardless of the ionisation state of the plasma, the
variation of spectral line broadening can be significant, even for low
intensity modulation. The nature of this broadening is not thermal but is
mostly turbulent. This places spectrometers in clear advantage over imaging
instruments for the detection of the sausage mode. The modulation of all
quantities is considerably affected by the line-of-sight angle, and especially
by the spatial and temporal resolution when these are on the order of the
mode's wavelength and period. This places high constraints on instrumentation.


title: On the Radius of Analyticity of Solutions to the Cubic Szeg\"o Equation

abstract:
  This paper is concerned with the cubic Szeg\H{o} equation $$ i\partial_t
u=\Pi(|u|^2 u), $$ defined on the $L^2$ Hardy space on the one-dimensional
torus $\mathbb T$, where $\Pi: L^2(\mathbb T)\rightarrow L^2_+(\mathbb T)$ is
the Szeg\H{o} projector onto the non-negative frequencies. For analytic initial
data, it is shown that the solution remains spatial analytic for all time $t\in
(-\infty,\infty)$. In addition, we find a lower bound for the radius of
analyticity of the solution. Our method involves energy-like estimates of the
special Gevrey class of analytic functions based on the $\ell^1$ norm of
Fourier transforms (the Wiener algebra).


title:
Adaptivity of averaged stochastic gradient descent to local strong
  convexity for logistic regression

abstract:
  In this paper, we consider supervised learning problems such as logistic
regression and study the stochastic gradient method with averaging, in the
usual stochastic approximation setting where observations are used only once.
We show that after $N$ iterations, with a constant step-size proportional to
$1/R^2 \sqrt{N}$ where $N$ is the number of observations and $R$ is the maximum
norm of the observations, the convergence rate is always of order
$O(1/\sqrt{N})$, and improves to $O(R^2 / \mu N)$ where $\mu$ is the lowest
eigenvalue of the Hessian at the global optimum (when this eigenvalue is
greater than $R^2/\sqrt{N}$). Since $\mu$ does not need to be known in advance,
this shows that averaged stochastic gradient is adaptive to \emph{unknown
local} strong convexity of the objective function. Our proof relies on the
generalized self-concordance properties of the logistic loss and thus extends
to all generalized linear models with uniformly bounded features.


title: On the completeness of trajectories for some mechanical systems

abstract:
  The classical tools which ensure the completeness of vector fields and second
order differential equations for mechanical systems are revisited. Possible
extensions in three directions are discussed: infinite dimensional Banach and
Hilbert manifolds, Finsler metrics and pseudo-Riemannian spaces, including
links with some relativistic spacetimes. Special emphasis is taken in the
cleaning up of known techniques, the statement of open questions and the
exploration of prospective frameworks.


title:
On the global well-posedness for Euler equations with unbounded
  vorticity

abstract:
  In this paper, we are interested in the global persistence regularity for the
2D incompressible Euler equations in some function spaces allowing unbounded
vorticities. More precisely, we prove the global propagation of the vorticity
in some weighted Morrey-Campanato spaces and in this framework the velocity
field is not necessarily Lipschitz but belongs to the log-Lipschitz class
$L^\alpha L,$ for some $\alpha\in (0,1).$


title: Template matching with noisy patches: A contrast-invariant GLR test

abstract:
  Matching patches from a noisy image to atoms in a dictionary of patches is a
key ingredient to many techniques in image processing and computer vision. By
representing with a single atom all patches that are identical up to a
radiometric transformation, dictionary size can be kept small, thereby
retaining good computational efficiency. Identification of the atom in best
match with a given noisy patch then requires a contrast-invariant criterion. In
the light of detection theory, we propose a new criterion that ensures contrast
invariance and robustness to noise. We discuss its theoretical grounding and
assess its performance under Gaussian, gamma and Poisson noises.


title:
On Titchmarsh-Weyl functions and eigenfunction expansions of first-order
  symmetric systems

abstract:
  We study general (not necessarily Hamiltonian) first-order symmetric systems
$J y'(t)-B(t)y(t)=\D(t) f(t)$ on an interval $\cI=[a,b> $ with the regular
endpoint $a$. It is assumed that the deficiency indices $n_\pm(\Tmi)$ of the
minimal relation $\Tmi$ in $\LI$ satisfy $n_-(\Tmi)\leq n_+(\Tmi)$. By using a
Nevanlinna boundary parameter $\tau=\tau(\l)$ at the singular endpoint $b$ we
define self-adjoint and $\l$-depending Nevanlinna boundary conditions which are
analogs of separated self-adjoint boundary conditions for Hamiltonian systems.
With a boundary value problem involving such conditions we associate the
$m$-function $m(\cd)$, which is an analog of the Titchmarsh-Weyl coefficient
for the Hamiltonian system. By using $m$-function we obtain the Fourier
transform $V:\LI\to L^2(\Si)$ with the spectral function $\Si(\cd)$ of the
minimally possible dimension. If $V$ is an isometry, then the (exit space)
self-adjoint extension $\wt T$ of $\Tmi$ induced by the boundary problem is
unitarily equivalent to the multiplication operator in $L^2(\Si)$; hence the
spectrum of $\wt T$ is defined by the spectral function $\Si(\cd)$. We show
that all the objects of the boundary problem are determined by the parameter
$\tau$, which enables us to parametrize all spectral function $\Si(\cd) $
immediately in terms of $\tau$. Similar results for various classes of boundary
problems were obtained by Kac and Krein, Fulton, Hinton and Shaw and other
authors.


title: The GIM Mechanism: origin, predictions and recent uses

abstract:
  The GIM Mechanism was introduced by Sheldon L. Glashow, John Iliopoulos and
Luciano Maiani in 1970, to explain the suppression of Delta S=1, 2 neutral
current processes and is an important element of the unified theories of the
weak and electromagnetic interactions. Origin, predictions and uses of the GIM
Mechanism are illustrated. Flavor changing neutral current processes (FCNC)
represent today an important benchmark for the Standard Theory and give strong
limitations to theories that go beyond ST in the few TeV region. Ideas on the
ways constraints on FCNC may be imposed are briefly described.


title:
Evolution of neutron star + He star binaries: an alternative
  evolutionary channel to intermediate-mass binary pulsars

abstract:
  It is difficult for intermediate-mass X-ray binaries to form compact
intermediate-mass binary pulsars (IMBPs) with a short orbital-period ($\la 3
\rm d$), which have a heavy ($\ga 0.4 M_{\odot}$) CO or ONeMg white dwarf
companions. Since neutron star + He star binaries may experience
common-envelope evolution, they have some advantage to account for the
formation of short orbital-period IMBPs. In this work, we explore the
probability of IMBPs formed by this evolutionary channel. Using Eggleton's
stellar evolution code, considering that the dead pulsars were spun up by the
accreting material and angular momentum from the He star companions, we have
calculated the evolution of a large number of neutron star + He star binaries.
Our simulated results indicate that, the NS + He star evolutionary channel can
produce IMBPs with a WD of $\sim0.5 - 1.1 M_{\odot}$ and an orbital period of
$0.03 - 20$ d, in which pulsars have a spin-period of $1.4 - 200$ ms. Comparing
the calculated results with the observational parameters (spin period and
orbital period) of 9 compact IMBPs, the NS + He star evolutionary channel can
account for the formation of 4 sources. Therefore, NS + He star binaries offer
an alternative evolutionary channel to compact IMBPs.


title:
On the existence of tangential holomorphic vector fields vanishing at an
  infinite type point

abstract:
  The purpose of this article is to investigate the holomorphic vector fields
tangent to a real hypersurface in $\mathbb C^2$ vanishing at an infinite type
point.


title: Semiclassical dynamics of horizons in spherically symmetric collapse

abstract:
  In this work, we consider a semiclassical description of the spherically
symmetric gravitational collapse with a massless scalar field. In particular,
we employ an effective scenario provided by holonomy corrections from loop
quantum gravity, to the homogeneous interior spacetime. The singularity that
would arise at the final stage of the corresponding classical collapse, is
resolved in this context and is replaced by a bounce. Our main purpose is to
investigate the evolution of trapped surfaces during this semiclassical
collapse. Within this setting, we obtain a threshold radius for the collapsing
shells in order to have horizons formation. In addition, we study the final
state of the collapse by employing a suitable matching at the boundary shell
from which quantum gravity effects are carried to the exterior geometry.


title: Reconciling extremely different concentration-mass relations

abstract:
  The concentration-mass relations proposed by Prada et al. (2012) and by Duffy
et al. (2008) on the scales of galaxy clusters show some of the largest
discrepancies among all the works present in literature. This is surprising
because they are both derived from the analysis of dark-matter halos forming in
LCDM simulations with similar set-ups. With the help of analytic models and
numerical simulations we investigate the origin of this discrepancy focusing on
the procedures used to derive the concentrations (circular velocity ratios
versus density profile fitting) and on the selection criteria used to bin the
halos (binning in maximum circular velocity versus binning in mass). We find
that both steps of the analysis have a large impact on the resulting c-M
relation. In particular, we show that the two c-M relations can be entirely
reconciled, if we account for these methodological differences. Our analysis
demonstrates that the concentration estimates are sensitive to the largely
different radial scales probed by a particular measurement method. This implies
that concentrations derived with different techniques (both in observations and
in simulations) must be compared over the same radial range.


title:
Invertibility of Submatrices of Pascal's Matrix and Birkhoff
  Interpolation

abstract:
  The infinite upper triangular Pascal matrix is $T = [\binom{j}{i}]$ for
$0\leq i,j$. It is easy to see that any leading principle square submatrix is
triangular with determinant $1$, hence invertible. In this paper, we
investigate the invertibility of arbitrary square submatrices $T_{r,c}$
comprised of rows $r=[r_0,\ldots,r_m]$ and columns $c=[c_0,\ldots,c_m]$ of $T$.
We show that $T_{r,c}$ is invertible iff $r \leq c$ (i.e., $r_i \leq c_i$ for
$i=0, \ldots, m$), or equivalently, iff all diagonal entries are nonzero. To
prove this result we establish a connection between the invertibility of these
submatrices and polynomial interpolation. In particular, we apply the theory of
Birkhoff interpolation and \polya{} systems.


title:
The uncorrelated long term gamma-ray and X-ray variability of blazars
  and its implications on disk-jet coupling

abstract:
  We examine the long term (~10 years) gamma-ray variability of blazars
observed by EGRET and Fermi and find that for six sources the average flux
varied by more than an order of magnitude. For two of these sources (PKS
0208-512 and PKS 0528+134), there were extensive observations (at various
observing periods) by EGRET. Hence these dramatic variations are not due to a
single short time-scale flare, but reflect long term changes in the average
flux. Over the last twenty years, these two sources were also the target of
several X-ray observatories (e.g. ROSAT, ASCA, RXTE, BeppoSAX, Chandra, Suzaku,
XMM-Newton and Swift). While the ratios of the average gamma-ray fluxes between
EGRET and Fermi observations are 22.9 +/- 1.9 and 12.6 +/- 1.5, their estimated
2-10 keV X-ray flux do not show such dramatic variations. The X-ray emission
from such flat spectrum radio quasars (FSRQs) are believed to be due to
synchrotron self Compton, while gamma-rays originate from inverse
Comptonization of external soft photons from an accretion disk and/or broad
line region. We argue that in this scenario, the only explanation for the
uncorrelated variability is that there was an order of magnitude decrease in
the external soft photons, while the jet parameters remained more or less
constant. This result indicates that perhaps the accretion and jet processes
are not tightly coupled in these sources.


title:
Reversal of the circular dichroism in the angle-resolved photoemission
  from Bi2Te3

abstract:
  The helical Dirac fermions at the surface of topological insulators show a
strong circular dichroism which has been explained as being due to either the
initial-state spin angular momentum, the initial-state orbital angular
momentum, or the handedness of the experimental setup. All of these
interpretations conflict with our data from Bi2Te3 which depend on the photon
energy and show several sign changes. Our one-step photoemission calculations
coupled to ab initio theory confirm the sign change and assign the dichroism to
a final-state effect. The spin polarization of the photoelectrons, instead,
remains a reliable probe for the spin in the initial state.


title: Thermalization of Levy flights: Path-wise picture in 2D

abstract:
  We analyze two-dimensional (2D) random systems driven by a symmetric L\'{e}vy
stable noise which, under the sole influence of external (force) potentials
$\Phi (x) $, asymptotically set down at Boltzmann-type thermal equilibria. Such
behavior is excluded within standard ramifications of the Langevin approach to
L\'{e}vy flights. In the present paper we address the response of L\'{e}vy
noise not to an external conservative force field, but directly to its
potential $\Phi (x)$. We prescribe a priori the target pdf $\rho_*$ in the
Boltzmann form $\sim \exp[- \Phi (x)]$ and next select the L\'evy noise of
interest. Given suitable initial data, this allows to infer a reliable
path-wise approximation to a true (albeit analytically beyond the reach)
solution of the pertinent master equation, with the property $\rho
(x,t)\rightarrow \rho_*(x)$ as time $t$ goes to infinity. We create a suitably
modified version of the time honored Gillespie's algorithm, originally invented
in the chemical kinetics context. A statistical analysis of generated sample
trajectories allows us to infer a surrogate pdf dynamics which consistently
sets down at a pre-defined target pdf. We pay special attention to the response
of the 2D Cauchy noise to an exemplary locally periodic "potential landscape"
$\Phi (x), x\in R^2$.


title: Machine learning of hierarchical clustering to segment 2D and 3D images

abstract:
  We aim to improve segmentation through the use of machine learning tools
during region agglomeration. We propose an active learning approach for
performing hierarchical agglomerative segmentation from superpixels. Our method
combines multiple features at all scales of the agglomerative process, works
for data with an arbitrary number of dimensions, and scales to very large
datasets. We advocate the use of variation of information to measure
segmentation accuracy, particularly in 3D electron microscopy (EM) images of
neural tissue, and using this metric demonstrate an improvement over competing
algorithms in EM and natural images.


title:
Band-edge Exciton States in a Single-walled Carbon Nanotube Revealed by
  Magneto-optical Spectroscopy in Ultra-high Magnetic Field

abstract:
  We report high field magneto-optical study on the first and second sub-band
transitions of single-chirality single-walled carbon nanotubes. The ordering
and relative energy splitting between bright and dark excitonic states were
found to be inverse between the first and second subbands. We verified that the
zero-momentum dark singlet exciton lies below the bright exciton for the first
subband transitions, while for the second sub-band transitions, it was found to
have higher energy than the bright excitonic state. Effect of this peculiar
excitonic structure was found to manifest itself in distinctive Aharonov-Bohm
splitting in ultra-high magnetic fields up to 190 T.


title:
Inference about ATE from Observational Studies with Continuous Outcome
  and Unmeasured Confounding

abstract:
  For settings with a binary treatment and a binary outcome, instrumental
variables can be used to construct bounds on a causal treatment effect. With
continuous outcomes, meaningful bounds are more difficult to obtain because the
domain of the outcome is typically unrestricted. In this paper, we combine an
instrumental variable and subjective assumptions in the context of an obser-
vational cohort study of HIV-infected women to construct meaningful bounds on
the initial-stage causal effect of antiretroviral therapy on CD4 count. The
subjective assumptions are encoded in terms of the potential outcomes that are
identified by observed data as well as a sensitivity parameter that captures
the impact of unmeasured confounding. Measured confounding is adjusted using
the method of inverse probability weighting (IPW). With extra information from
an IV, we quantify both the causal treatment effect and the degree of the
unmea- sured confounding. We demonstrate our method by analyzing data from the
HIV Epidemiology Research Study.


title:
Mismatched Decoding: Error Exponents, Second-Order Rates and Saddlepoint
  Approximations

abstract:
  This paper considers the problem of channel coding with a given (possibly
suboptimal) maximum-metric decoding rule. A cost-constrained random-coding
ensemble with multiple auxiliary costs is introduced, and is shown to achieve
error exponents and second-order coding rates matching those of
constant-composition random coding, while being directly applicable to channels
with infinite or continuous alphabets. The number of auxiliary costs required
to match the error exponents and second-order rates of constant-composition
coding is studied, and is shown to be at most two. For i.i.d. random coding,
asymptotic estimates of two well-known non-asymptotic bounds are given using
saddlepoint approximations. Each expression is shown to characterize the
asymptotic behavior of the corresponding random-coding bound at both fixed and
varying rates, thus unifying the regimes characterized by error exponents,
second-order rates and moderate deviations. For fixed rates, novel exact
asymptotics expressions are obtained to within a multiplicative 1+o(1) term.
Using numerical examples, it is shown that the saddlepoint approximations are
highly accurate even at short block lengths.


title:
Second-Order Rate Region of Constant-Composition Codes for the
  Multiple-Access Channel

abstract:
  This paper studies the second-order asymptotics of coding rates for the
discrete memoryless multiple-access channel with a fixed target error
probability. Using constant-composition random coding, coded time-sharing, and
a variant of Hoeffding's combinatorial central limit theorem, an inner bound on
the set of locally achievable second-order coding rates is given for each point
on the boundary of the capacity region. It is shown that the inner bound for
constant-composition random coding includes that recovered by i.i.d. random
coding, and that the inclusion may be strict. The inner bound is extended to
the Gaussian multiple-access channel via an increasingly fine quantization of
the inputs.


title:
Homology computation for a class of contact structures on $T^3$ and
  equivariant reductions

abstract:
  We consider a family of tight contact structures on the three-dimensional
torus and we compute the relative Contact Homology by using the variational
theory of critical points at infinity. We will also show some algebraic
equivariant homology reductions.


title: Co-Occurring HIV Risk Behaviors among Males Entering Jail

abstract:
  This paper examines the pattern of HIV risk behaviors among male jail
detainees. From multivariate analyses of baseline data from an HIV intervention
study of ours, we find that: (1) cocaine use, heroin use and multiple sexual
partners; and (2) heavy drinking and marijuana are often co-occurring among
this population. From pairwise analyses, we find that (1) heroin and IDU (2)
unprotected sexes with main, with non-main, and in last sexual encounter are
mostly co-occurring. IDU is found to be associated with middle ages (30-40) and
multiple prior incarcerations, and multiple sex partners associated young males
with age <30, African American race, and low education. Our findings suggest
that efficient interventions to reduce HIV infection in this high-risk
population may have to target on these behaviors simultaneously and be
demographically adapted.


title: Maximum Likelihood Fusion of Stochastic Maps

abstract:
  The fusion of independently obtained stochastic maps by collaborating mobile
agents is considered. The proposed approach includes two parts: matching of
stochastic maps and maximum likelihood alignment. In particular, an affine
invariant hypergraph is constructed for each stochastic map, and a bipartite
matching via a linear program is used to establish landmark correspondence
between stochastic maps. A maximum likelihood alignment procedure is proposed
to determine rotation and translation between common landmarks in order to
construct a global map within a common frame of reference. A main feature of
the proposed approach is its scalability with respect to the number of
landmarks: the matching step has polynomial complexity and the maximum
likelihood alignment is obtained in closed form. Experimental validation of the
proposed fusion approach is performed using the Victoria Park benchmark
dataset.


title:
Surprising Asymptotic Conical Structure in Critical Sample
  Eigen-Directions

abstract:
  The aim of this paper is to establish several deep theoretical properties of
principal component analysis for multiple-component spike covariance models.
Our new results reveal a surprising asymptotic conical structure in critical
sample eigendirections under the spike models with distinguishable (or
indistinguishable) eigenvalues, when the sample size and/or the number of
variables (or dimension) tend to infinity. The consistency of the sample
eigenvectors relative to their population counterparts is determined by the
ratio between the dimension and the product of the sample size with the spike
size. When this ratio converges to a nonzero constant, the sample eigenvector
converges to a cone, with a certain angle to its corresponding population
eigenvector.In the High Dimension, Low Sample Size case, the angle between the
sample eigenvector and its population counterpart converges to a limiting
distribution.Several generalizations of the multi-spike covariance models are
also explored, and additional theoretical results are presented.


title:
High-frequency resolvent estimates on asymptotically Euclidean warped
  products

abstract:
  We consider the resolvent on asymptotically Euclidean warped product
manifolds in an appropriate 0-Gevrey class, with trapped sets consisting of
only finitely many components. We prove that the high-frequency resolvent is
either bounded by $C_\epsilon |\lambda|^\epsilon$ for any $\epsilon>0$, or
blows up faster than any polynomial (at least along a subsequence). A stronger
result holds if the manifold is analytic. The method of proof is to exploit the
warped product structure to separate variables, obtaining a one-dimensional
semiclassical Schr\"odinger operator. We then classify the microlocal resolvent
behaviour associated to every possible type of critical value of the potential,
and translate this into the associated resolvent estimates. Weakly stable
trapping admits highly concentrated quasimodes and fast growth of the
resolvent. Conversely, using a delicate inhomogeneous blowup procedure loosely
based on the classical positive commutator argument, we show that any weakly
unstable trapping forces at least some spreading of quasimodes.
  As a first application, we conclude that either there is a resonance free
region of size $| \Im \lambda | \leq C_\epsilon | \Re \lambda |^{-1-\epsilon}$
for any $\epsilon>0$, or there is a sequence of resonances converging to the
real axis faster than any polynomial. Again, a stronger result holds if the
manifold is analytic. As a second application, we prove a spreading result for
weak quasimodes in partially rectangular billiards.


title: Sterile neutrino analysis of reactor-neutrino oscillation

abstract:
  Sterile neutrinos are one candidate to explain anomalies in neutrino
oscillations. The mass-difference-driving oscillation between flavors can be
probed only within specific combinations of baseline and flight energy. For a
neutrino whose mass is completely unknown, it is necessary to scan all
available ranges in spectrum and all accessible baselines. Here, we present
four-neutrino analysis of the results announced by RENO and Daya Bay, which
performed the definitive measurements of $\theta_{13}$ based on the
disappearance of the inverse-beta-decay antineutrino at km-order baselines. Our
results within 3+1 scheme include the exclusion curve of $\Delta m_{41}$ vs.
$\theta_{14}$, and the adjustment of $\theta_{13}$ due to the contribution of
$\theta_{14}$ to the disappearance of electron antineutrinos.


title: Modified current induced domain wall motion in GaMnAs nanowire

abstract:
  We report on current induced domain wall propagation in a patterned GaMnAs
microwire with perpendicular magnetization. An unexpected slowing down of the
propagation velocity has been found when the moving domain wall extends over
only half of the width of the wire. This slowing down is related to the
elongation of a longitudinal wall along the axis of the wire. By using an
energy balance argument, the expected theoretical dependence of the velocity
change has been calculated and compared with the experimental results.
According to this, the energy associated to the longitudinal domain wall should
change when a current passes through the wire. These results provide possible
evidence of transverse spin diffusion along a longitudinal domain wall.


title: Compression as a universal principle of animal behavior

abstract:
  A key aim in biology and psychology is to identify fundamental principles
underpinning the behavior of animals, including humans. Analyses of human
language and the behavior of a range of non-human animal species have provided
evidence for a common pattern underlying diverse behavioral phenomena: words
follow Zipf's law of brevity (the tendency of more frequently used words to be
shorter), and conformity to this general pattern has been seen in the behavior
of a number of other animals. It has been argued that the presence of this law
is a sign of efficient coding in the information theoretic sense. However, no
strong direct connection has been demonstrated between the law and compression,
the information theoretic principle of minimizing the expected length of a
code. Here we show that minimizing the expected code length implies that the
length of a word cannot increase as its frequency increases. Furthermore, we
show that the mean code length or duration is significantly small in human
language, and also in the behavior of other species in all cases where
agreement with the law of brevity has been found. We argue that compression is
a general principle of animal behavior, that reflects selection for efficiency
of coding.

categories: q-bio.NC cs.CL cs.IT math.IT physics.data-an q-bio.QM


title: Vacuum fluctuations and generalized boundary conditions

abstract:
  We present a study of the static and dynamical Casimir effects for a quantum
field theory satisfying generalized Robin boundary condition, of a kind that
arises naturally within the context of quantum circuits. Since those conditions
may also be relevant to measurements of the dynamical Casimir effect, we
evaluate their role in the concrete example of a real scalar field in 1+1
dimensions, a system which has a well-known mechanical analogue involving a
loaded string.


title: Hot water in the inner 100 AU of the Class 0 protostar NGC1333 IRAS2A

abstract:
  Evaporation of water ice above 100 K in the inner few 100 AU of low-mass
embedded protostars (the so-called hot core) should produce quiescent water
vapor abundances of ~10^-4 relative to H2. Observational evidence so far points
at abundances of only a few 10^-6. However, these values are based on spherical
models, which are known from interferometric studies to be inaccurate on the
relevant spatial scales. Are hot cores really that much drier than expected, or
are the low abundances an artifact of the inaccurate physical models? We
present deep velocity-resolved Herschel-HIFI spectra of the 3(12)-3(03) lines
of H2-16O and H2-18O (1097 GHz, Eup/k = 249 K) in the low-mass Class 0
protostar NGC1333 IRAS2A. A spherical radiative transfer model with a power-law
density profile is unable to reproduce both the HIFI data and existing
interferometric data on the H2-18O 3(13)-2(20) line (203 GHz, Eup/k = 204 K).
Instead, the HIFI spectra likely show optically thick emission from a hot core
with a radius of about 100 AU. The mass of the hot core is estimated from the
C18O J=9-8 and 10-9 lines. We derive a lower limit to the hot water abundance
of 2x10^-5, consistent with the theoretical predictions of ~10^-4. The revised
HDO/H2O abundance ratio is 1x10^-3, an order of magnitude lower than previously
estimated.


title:
Correlated, Precision Measurements of \theta_{23} and $\delta$ using
  only the Electron Neutrino Appearance Experiments

abstract:
  Precision measurement of the leptonic CP violating phase $\delta$ will suffer
from the, then surviving, large uncertainty of sin^2 \theta_{23} of 10-20% in
the experimentally interesting region near maximal mixing of \theta_{23}. We
advocate a new method for determination of both \theta_{23} and $\delta$ at the
same time using only the \nu_e and \bar{\nu}_e appearance channels, and show
that sin^2 \theta_{23} can be determined automatically with much higher
accuracy, approximately a factor of six, than \sin \delta. In this method, we
identify a new degeneracy for the simultaneous determination of \theta_{23} and
\delta, the \theta_{23} intrinsic degeneracy, which must be resolved in order
to achieve precision measurement of these two parameters. Spectral information
around the vacuum oscillation maxima is shown to be the best way to resolve
this degeneracy.


title: Generalized Killing spinors on Einstein manifolds

abstract:
  We study generalized Killing spinors on compact Einstein manifolds with
positive scalar curvature. This problem is related to the existence compact
Einstein hypersurfaces in manifolds with parallel spinors, or equivalently, in
Riemannian products of flat spaces, Calabi-Yau, hyperkaehler, G_2 and Spin(7)
manifolds.


title:
Spontaneous CP violation from vacuum alignment in $S_4$ models of
  leptons

abstract:
  We construct models of leptons based on $S_4$ family symmetry combined with a
generalised CP symmetry $H_{CP}$. We show how the flavon potential can
spontaneously break the symmetry $S_4 \rtimes H_{CP}$ down to $Z_2 \times
H^{\nu}_{CP}$ in the neutrino sector, where the choice of preserved CP symmetry
$H^{\nu}_{CP}$ is controlled by free (real) parameters in the flavon potential.
We propose two realistic models of this kind, one at the effective level and
one at the renormalisable level. Both models predict trimaximal lepton mixing
with CP being either fully preserved or maximally broken, with the intermediate
possibility forbidden by the structure of the models.


title:
Tunneling time problem: At the intersection of quantum mechanics,
  classical probability theory and special relativity

abstract:
  After the review by Hauge and Stovneng the old question of "How long does it
take to tunnel through the barrier?" has not still lost its relevance. As
before, there is no clear answer to this question even for the one-dimensional
completed scattering (OCS). In this paper we show that this seemingly simple
question stands alongside with such fundamental problems of quantum mechanics
(QM) as the Schrodinger's-cat and and EPR-Bohm paradoxes. Their common feature
is that the states of a scattered particle, a radioactive atom and electron
EPR-pair represent pure {\it micro-cat} states. It is widely accepted that the
EPR-Bohm paradox implies the non-existence of local hidden variables (LHVs),
the cat paradox represents a macro-objectification problem and the tunneling
time is an observer-dependent quantity whose definitions must be 'operational'.
At the same time, according to the probabilistic approach (Accardi, Khrennikov,
Philipp, Hess {\it et al.}) to Bell's inequality that underlies the EPR-Bohm
experiments, its experimental violation means simply that it contains
probability distributions associated with mutually incompatible statistical
data. We argue that this approach must be extended onto micro-cat states
because they describe, too, mutually incompatible statistical data. The current
practice to interpret the squared modulus of a micro-cat state as the
probability density should be recognized as erroneous. It is this practice that
makes QM incompatible with classical physical theories and, thereby, makes the
micro-world 'unspeakable'. The known 'operational' tunneling-time concepts,
elaborated in line with this practice, are logically inconsistent. We argue
that the TTP and the cat paradox must be solved at the level of single
electrons and atoms, without resorting to environment and measurement contexts.
We present a new model of the OCS and solve the TTP on its basis.


title: Variance estimation for Brier Score decomposition

abstract:
  The Brier Score is a widely-used criterion to assess the quality of
probabilistic predictions of binary events. The expectation value of the Brier
Score can be decomposed into the sum of three components called reliability,
resolution, and uncertainty which characterize different forecast attributes.
Given a dataset of forecast probabilities and corresponding binary
verifications, these three components can be estimated empirically. Here,
propagation of uncertainty is used to derive expressions that approximate the
sampling variances of the estimated components. Variance estimates are provided
for both the traditional estimators, as well as for refined estimators that
include a bias correction. Applications of the derived variance estimates to
artificial data illustrate their validity, and application to a meteorological
prediction problem illustrates a possible use case. The observed increase of
variance of the bias-corrected estimators is discussed.


title:
Quantitative easing is an incomplete strategy that must be accompanied
  by the nullification of debt

abstract:
  Compound interest as well as inflation grows exponentially with time, whereas
other means to repay debt grow polynomially. For this and other, mostly
political, reasons, debt without inflation is unsustainable. We suggest a
discontinuous way to eliminate debt by nullifying it. This scenario is
preferable to current central bank strategies of quantitative easing because it
allows the disposal of debt without hyperinflation or bloated balance sheets.


title:
Polaron-like vortices, dissociation transition and self induced pinning
  in magnetic superconductors

abstract:
  In magnetic superconductors vortices polarize spins nonuniformly and
repolarize them when moving. At a low spin relaxation rate and at low bias
currents vortices carrying magnetic polarization clouds become polaron-like and
their velocities are determined by the effective drag coefficient which is
significantly bigger than the Bardeen-Stephen (BS) one. As current increases,
vortices release polarization clouds and the velocity as well as the voltage in
the I-V characteristics jump to values corresponding to the BS drag coefficient
at a critical current $J_c$. The nonuniform components of the magnetic field
and magnetization drop as velocity increases resulting in weaker polarization
and {\it discontinuous} dynamic dissociation depinning transition.
Experimentally the jump shows up as a depinning transition and the
corresponding current at the jump is the depinning current. As current
decreases, on the way back, vortices are retrapped by polarization clouds at
the current $J_r<J_c$. As a result, polaronic effect suppresses dissipation and
enhances critical current. Borocarbides (RE)Ni$_2$B$_2$C with a short
penetration length and highly polarizable rare earth spins seem to be optimal
systems for a detailed study of vortex polaron formation by measuring I-V
characteristics. We propose also to use superconductor-magnet multilayer
structure to study polaronic mechanism of pinning with the goal to achieve high
critical currents. The magnetic layers should have large magnetic
susceptibility to enhance the coupling between vortices and magnetization in
magnetic layers while the relaxation of the magnetization should be slow. For
Nb and proper magnet multilayer structure, we estimate the critical current
density $J_c\sim 10^{9}\ \rm{A/m^2}$ at magnetic field $B\approx 1$ T.


title:
Nonlocal van der Waals functionals: The case of rare-gas dimers and
  solids

abstract:
  Recently, the nonlocal van der Waals (vdW) density functionals [M. Dion, H.
Rydberg, E. Schroeder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett.
92, 246401 (2004)] have attracted considerable attention due to their good
performance for systems where weak interactions are important. Since the
physics of dispersion is included in these functionals, they are usually more
accurate and show less erratic behavior than the semilocal and hybrid methods.
In this work, several variants of the vdW functionals have been tested on
rare-gas dimers (from He2 to Kr2) and solids (Ne, Ar, and Kr) and their
accuracy compared to standard semilocal approximations supplemented or not by
an atom-pairwise dispersion correction [S. Grimme, J. Antony, S. Ehrlich, and
H. Krieg, J. Chem. Phys. 132, 154104 (2010)]. An analysis of the results in
terms of energy decomposition is also provided.


title:
Some notes on the abstraction operation for Multi-Terminal Binary
  Decision Diagrams

abstract:
  The starting point of this work are inaccurate statements found in the
literature for Multi-terminal Binary Decision Diagrams (MTBDDs) regarding the
well-definedness of the MTBDD abstraction operation. The statements try to
relate an operation * on a set of terminal values M to the property that the
abstraction over this operation does depend on the order of the abstracted
variables. This paper gives a necessary and sufficient condition for the
independence of the abstraction operation of the order of the abstracted
variables in the case of an underlying monoid and it treats the more general
setting of a magma.


title: Four Fermion Interactions in Non-Abelian Gauge Theory

abstract:
  We continue our earlier study of the phase structure of a SU(2) gauge theory
whose action contains additional chirally invariant four fermion interactions.
Our lattice theory uses a reduced staggered fermion formalism to generate two
Dirac flavors in the continuum limit. In the current study we have tried to
reduce lattice spacing and taste breaking effects by using an improved fermion
action incorporating stout smeared links. As in our earlier study we observe
two regimes; for weak gauge coupling the chiral condensate behaves as an order
parameter differentiating a phase at small four fermi coupling where the
condensate vanishes from a phase at strong four fermi coupling in which chiral
symmetry is spontaneously broken. This picture changes qualitatively when the
gauge coupling is strong enough to cause confinement; in this case we observe a
first order phase transition for some critical value of the four fermi coupling
associated with a strong enhancement of the chiral condensate. We observe that
this critical four fermi coupling varies monotonically with bare gauge coupling
- decreasing, as expected, as the gauge coupling is increased. We have checked
that these results remain stable under differing levels of smearing. They
appear to rule out the appearance of new fixed points associated with chirally
invariant four fermion interactions in confining non abelian gauge theories.


title: On Back-reaction in Special Relativity

abstract:
  Back-reaction of fields plays an important role in the generation of particle
masses and the mass-energy equivalence of special relativity, but the most
natural demonstrations using classical models result in apparent errors such as
the notorious "4/3" problem. Here we discuss the resolution of these
discrepancies within the underlying atomic description of matter, with the aim
of encouraging classroom discussion of back-reaction and its connection to
relativistic effects.


title:
A Stochastic Partially Reversible Investment Problem on a Finite
  Time-Horizon: Free-Boundary Analysis

abstract:
  We study a continuous-time, finite horizon, stochastic partially reversible
investment problem for a firm producing a single good in a market with
frictions. The production capacity is modeled as a one-dimensional,
time-homogeneous, linear diffusion controlled by a bounded variation process
which represents the cumulative investment-disinvestment strategy. We associate
to the investment-disinvestment problem a zero-sum optimal stopping game and
characterize its value function through a free-boundary problem with two moving
boundaries. These are continuous, bounded and monotone curves that solve a
system of non-linear integral equations of Volterra type. The optimal
investment-disinvestment strategy is then shown to be a diffusion reflected at
the two boundaries.


title: Hamiltonian Thermostats Fail to Promote Heat Flow

abstract:
  Hamiltonian mechanics can be used to constrain temperature simultaneously
with energy. We illustrate the interesting situations that develop when two
different temperatures are imposed within a composite Hamiltonian system. The
model systems we treat are "phi-4" chains, with quartic tethers and quadratic
nearest-neighbor Hooke's-law interactions. This model is known to satisfy
Fourier's law. Our prototypical problem sandwiches a Newtonian subsystem
between hot and cold Hamiltonian reservoir regions. We have characterized four
different Hamiltonian reservoir types. There is no tendency for any of these
two-temperature Hamiltonian simulations to transfer heat from the hot to the
cold degrees of freedom. Evidently steady heat flow simulations require energy
sources and sinks, and are therefore incompatible with Hamiltonian mechanics.


title:
Reconstruction of Inert Doublet Scalars at the International Linear
  Collider

abstract:
  We study collider signatures for extra scalar bosons in the inert doublet
model at the international linear collider (ILC). The inert doublet model is a
simple extension of the standard model by introducing an additional
isospin-doublet scalar field which is odd under an unbroken Z_2 symmetry. The
model predicts four kinds of Z_2-odd scalar bosons, and the lightest of them
becomes stable and a candidate of the dark matter as long as it is electrically
neutral. Taking into account the constraints from various theoretical and
phenomenological conditions, we perform a simulation study for the distinctive
signatures of the extra scalars over the standard-model background
contributions at the ILC with the center-of-mass energy of sqrt{s} = 250 GeV
and 500 GeV. We further discuss observables for determination of the mass of
the scalars. We find that the parameter regions which cannot be detected at the
large hadron collider can be probed at the ILC.


title:
Inflation Uncertainty, Output Growth Uncertainty and Macroeconomic
  Performance: Comparing Alternative Exchange Rate Regimes in Eastern Europe

abstract:
  In the late 90's, after severe financial and economic crisis, accompanied by
inflation and exchange rate instability, Eastern Europe emerged into two groups
of countries with radically contrasting monetary regimes (Currency Boards and
Inflation targeting). The task of our study is to compare econometrically the
performance of these two regimes in terms of the relationship between
inflation, output growth, nominal and real uncertainties from 2000 till now. In
other words, we test the hypothesis of non-neutrality of monetary and exchange
rate regimes with respect to these connections. In a whole, the empirical
results do not allow us to judge which monetary regime is more appropriate and
reasonable to assume. EU enlargement is one of the possible explanations for
the numbing of the differences and the lack of coherence between the two
regimes in terms of inflation, growth and their uncertainties


title:
Lagrangian theory of structure formation in relativistic cosmology II:
  average properties of a generic evolution model

abstract:
  Kinematical and dynamical properties of a generic inhomogeneous cosmological
model, spatially averaged with respect to free-falling (generalized
fundamental) observers, are investigated for the matter model irrotational
dust. Paraphrasing a previous Newtonian investigation, we present a
relativistic generalization of a backreaction model based on volume-averaging
the Relativistic Zeldovich Approximation. In this model we investigate the
effect of kinematical backreaction on the evolution of cosmological parameters
as they are defined in an averaged inhomogeneous cosmology, and we show that
the backreaction model interpolates between orthogonal symmetry properties by
covering subcases of the plane-symmetric solution, the Lemaitre-Tolman-Bondi
solution and the Szekeres solution. We so obtain a powerful model that lays the
foundations for quantitatively addressing curvature inhomogeneities as they
would be interpreted as Dark Energy or Dark Matter in a quasi-Newtonian
cosmology. The present model, having a limited architecture due to an assumed
FLRW background, is nevertheless capable of replacing 1/4 of the needed amount
for Dark Energy on domains of 200 Mpc in diameter for typical (one-sigma)
fluctuations in a CDM initial power spectrum. However, the model is far from
explaining Dark Energy on larger scales (spatially), where a 6% effect on 400
Mpc domains is identified that can be traced back to an on average negative
intrinsic curvature today. One drawback of the quantitative results presented
is the fact that the epoch when backreaction is effective on large scales and
leads to volume acceleration lies in the future. We discuss this issue in
relation to the initial spectrum, the Dark Matter problem, the coincidence
problem, and the fact that large-scale Dark Energy is an effect on the past
light cone (not spatial), and we pinpoint key elements of future research.


title: Science with a wide-field UV transient explorer

abstract:
  The time-variable electromagnetic sky has been well-explored at a wide range
of wavelengths. Numerous high-energy space missions take advantage of the dark
Gamma-ray and X-ray sky and utilize very wide field detectors to provide almost
continuous monitoring of the entire celestial sphere. In visible light, new
wide-field ground-based surveys cover wide patches of sky with ever decreasing
cadence, progressing from monthly-weekly time scale surveys to sub-night
sampling. In the radio, new powerful instrumentation offers unprecedented
sensitivity over wide fields of view, with pathfinder experiments for even more
ambitious programs underway. In contrast, the ultra-violet (UV) variable sky is
relatively poorly explored, even though it offers exciting scientific
prospects. Here, we review the potential scientific impact of a wide-field UV
survey on the study of explosive and other transient events, as well as known
classes of variable objects, such as active galactic nuclei and variable stars.
We quantify our predictions using a fiducial set of observational parameters
which are similar to those envisaged for the proposed ULTRASAT mission. We show
that such a mission would be able to revolutionize our knowledge about massive
star explosions by measuring the early UV emission from hundreds of events,
revealing key physical parameters of the exploding progenitor stars. Such a
mission would also detect the UV emission from many tens of tidal-disruption
events of stars by super massive black holes at galactic nuclei and enable a
measurement of the rate of such events. The overlap of such a wide-field UV
mission with existing and planned gravitational-wave and high-energy neutrino
telescopes makes it especially timely.


title:
Universality in modelling non-equilibrium pattern formation in polariton
  condensates

abstract:
  The key to understanding the universal behaviour of systems driven away from
equilibrium lies in the common description obtained when particular microscopic
models are reduced to order parameter equations. Universal order parameter
equations written for complex matter fields are widely used to describe systems
as different as Bose-Einstein condensates of ultra cold atomic gases, thermal
convection, nematic liquid crystals, lasers and other nonlinear systems.
Exciton-polariton condensates recently realised in semiconductor microcavities
are pattern forming systems that lie somewhere between equilibrium
Bose-Einstein condensates and lasers. Because of the imperfect confinement of
the photon component, exciton-polaritons have a finite lifetime, and have to be
continuously re-populated. As photon confinement improves, the system more
closely approximates an equilibrium system. In this chapter we review a number
of universal equations which describe various regimes of the dynamics of
exciton-polariton condensates: the Gross-Pitaevskii equation, which models
weakly interacting equilibrium condensates, the complex Ginsburg-Landau
equation---the universal equation that describes the behaviour of systems in
the vicinity of a symmetry--breaking instability, and the complex
Swift-Hohenberg equation that in comparison with the complex Ginsburg-Landau
equation contains additional nonlocal terms responsible for spacial mode
selection. All these equations can be derived asymptotically from a generic
laser model given by Maxwell-Bloch equations. Such an universal framework
allows the unified treatment of various systems and continuously cross from one
system to another. We discuss the relevance of these equations, and their
consequences for pattern formation.


title:
Entanglement detection from conductance measurements in carbon nanotube
  Cooper pair splitters

abstract:
  Spin-orbit interaction provides a spin filtering effect in carbon nanotube
based Cooper pair splitters that allows us to determine spin correlators
directly from current measurements. The spin filtering axes are tunable by a
global external magnetic field. By a bending of the nanotube the filtering axes
on both sides of the Cooper pair splitter become sufficiently different that a
test of entanglement of the injected Cooper pairs through the Bell inequality
can be implemented. This implementation does not require noise measurements,
supports imperfect splitting efficiency and disorder, and does not demand a
full knowledge of the spin-orbit strength. Using a microscopic calculation we
demonstrate that entanglement detection by violation of the Bell inequality is
within the reach of current experimental setups.


title:
Study of low frequency acoustic signals from superheated droplet
  detector

abstract:
  The bubble nucleation process in superheated droplet detector (SDD) is
associated with the emission of an acoustic pulse that can be detected by an
acoustic sensor. We have studied the neutron and gamma-ray induced nucleation
events in a SDD with the active liquid R-12 (CCl2F2, b.p. -29.8oC) using a
condenser microphone sensor. A comparative study in the low frequency region (~
0-10kHz) for the neutron and gamma-ray induced nucleation is presented here.
From the analysis of the waveforms we observe a significant difference between
the neutron and gamma-ray induced acoustic events.


title: On the Lyapunov numbers

abstract:
  We introduce and study the Lyapunov numbers -- quantitative measures of the
sensitivity of a dynamical system $(X,f)$ given by a compact metric space $X$
and a continuous map $f:X \to X$. In particular, we prove that for a minimal
topologically weakly mixing system all Lyapunov numbers are the same.


title:
Distribution and Symmetric Distribution Regression Model for
  Histogram-Valued Variables

abstract:
  Histogram-valued variables are a particular kind of variables studied in
Symbolic Data Analysis where to each entity under analysis corresponds a
distribution that may be represented by a histogram or by a quantile function.
Linear regression models for this type of data are necessarily more complex
than a simple generalization of the classical model: the parameters cannot be
negative still the linear relationship between the variables must be allowed to
be either direct or inverse. In this work we propose a new linear regression
model for histogram-valued variables that solves this problem, named
Distribution and Symmetric Distribution Regression Model. To determine the
parameters of this model it is necessary to solve a quadratic optimization
problem, subject to non-negativity constraints on the unknowns; the error
measure between the predicted and observed distributions uses the Mallows
distance. As in classical analysis, the model is associated with a
goodness-of-fit measure whose values range between 0 and 1. Using the proposed
model, applications with real and simulated data are presented.


title: How to Schedule the Marketing of Products with Negative Externalities

abstract:
  In marketing products with negative externalities, a schedule which specifies
an order of consumer purchase decisions is crucial, since in the social network
of consumers, the decision of each consumer is negatively affected by the
choices of her neighbors. In this paper, we study the problems of finding a
marketing schedule for two asymmetric products with negative externalites. The
goals are two-fold: maximizing the sale of one product and ensuring regret-free
purchase decisions. We show that the maximization is NP-hard, and provide
efficient algorithms with satisfactory performance guarantees. Two of these
algorithms give regret-proof schedules, i.e. they reach Nash equilibria where
no consumers regret their previous decisions. Our work is the first attempt to
address these marketing problems from an algorithmic point of view.


title: Time-dependent Landauer-B\"uttiker formula for transient dynamics

abstract:
  We solve analytically the Kadanoff-Baym equations for a noninteracting
junction connected to an arbitrary number of noninteracting wide-band
terminals. The initial equilibrium state is properly described by the addition
of an imaginary track to the time contour. From the solution we obtain the
time-dependent electron densities and currents within the junction. The final
results are analytic expressions as a function of time, and therefore no time
propagation is needed - either in transient or in steady-state regimes. We
further present and discuss some applications of the obtained formulae.


title: Shaping frequency entangled qudits

abstract:
  Quantum entanglement between qudits - the d-dimensional version of qubits -
is relevant for advanced quantum information processing and provides deeper
insights in the nature of quantum correlations. Encoding qudits in the
frequency modes of photon pairs produced by continuous parametric
down-conversion enables access to high-dimensional states. By shaping the
energy spectrum of entangled photons, we demonstrate the creation,
characterization and manipulation of entangled qudits with dimension up to 4.
Their respective density matrices are reconstructed by quantum state
tomography. For qubits and qutrits we additionally measured the dependency of a
d-dimensional Bell parameter for various degrees of entanglement. Our
experiment demonstrates the ability to investigate the physics of
high-dimensional frequency entangled qu$d$it states which are of great
importance for quantum information science.


title: Walk Entropies in Graphs

abstract:
  Entropies based on walks on graphs and on their line-graphs are defined. They
are based on the summation over diagonal and off-diagonal elements of the
thermal Green's function of a graph also known as the communicability. The walk
entropies are strongly related to the walk regularity of graphs and
line-graphs. They are not biased by the graph size and have significantly
better correlation with the inverse participation ratio of the eigenmodes of
the adjacency matrix than other graph entropies. The temperature dependence of
the walk entropies is also discussed. In particular, the walk entropy of graphs
is shown to be non-monotonic for regular but non-walk-regular graphs in
contrast to non-regular graphs.


title:
The Jacobi-Rosochatius problem on an ellipsoid: the Lax representations
  and billiards

abstract:
  The Lax representations of the geodesic flow, the Jacobi-Rosochatius problem
and its perturbations by means of separable polynomial potentials, on a
ellipsoid are constructed. We prove complete integrability in the case of a
generic symmetric ellipsoid and describe analogous systems on complex
projective spaces. Also, we consider billiards within an ellipsoid under the
influence of the Hook and Rosochatius potentials between the impacts. A
geometric interpretation of the integrability analogous to the classical
Chasles and Poncelet theorems is given.


title:
In-Plane Focusing of Terahertz Surface Waves on a Gradient Index
  Metamaterial Film

abstract:
  We designed and implemented a gradient index metasurface for the in-plane
focusing of confined terahertz surface waves. We measured the spatial
propagation of the surface waves by two-dimensional mapping of the complex
electric field using a terahertz near-field spectroscope. The surface waves
were focused to a diameter of 500 \micro m after a focal length of approx. 2
mm. In the focus, we measured a field amplitude enhancement of a factor of 3.


title: Some integrals related to the Fermi function

abstract:
  Some elaborations regarding the Hilbert and Fourier transforms of Fermi
function are presented. The main result shows that the Hilbert transform of the
difference of two Fermi functions has an analytical expression in terms of the
$\Psi$ (digamma) function, while its Fourier transform is expressed by mean of
elementary functions. Moreover an integral involving the product of the
difference of two Fermi functions with its Hilbert transform is evaluated
analytically. These findings are of fundamental importance in discussing the
transport properties of electronic systems.


title: Duality theory for nonergodic actions

abstract:
  Generalizing work by Pinzari and Roberts, we characterize actions of a
compact quantum group G on C*-algebras in terms of what we call weak unitary
tensor functors from Rep G into categories of C*-correspondences. We discuss
the relation of our construction of a C*-algebra from a functor to some
well-known crossed product type constructions, such as cross-sectional algebras
of Fell bundles and crossed products by Hilbert bimodules. We also relate our
setting to recent work of De Commer and Yamashita by showing that any object in
a module C*-category over Rep G produces a weak unitary tensor functor, and, as
a consequence, actions can also be described in terms of (Rep G)-module
C*-categories. As an application we discuss deformations of C*-algebras by
cocycles on discrete quantum groups.


title: Impurities as a quantum thermometer for a Bose-Einstein condensate

abstract:
  We introduce a primary thermometer which measures the temperature of a
Bose-Einstein Condensate in the sub-nK regime. We show, using quantum Fisher
information, that the precision of our technique improves the state-of-the-art
in thermometry in the sub-nK regime. The temperature of the condensate is
mapped onto the quantum phase of an atomic dot that interacts with the system
for short times. We show that the highest precision is achieved when the phase
is dynamical rather than geometric and when it is detected through Ramsey
interferometry. Standard techniques to determine the temperature of a
condensate involve an indirect estimation through mean particle velocities made
after releasing the condensate. In contrast to these destructive measurements,
our method involves a negligible disturbance of the system.


title:
Spin stiffness calculation in anisotropic XY model with Ring exchange
  interaction

abstract:
  We present the spin wave theory of XY model with anisotropic nearest
neighbour (NN) interactions $J(J^{\prime})$ along the $x(y)$ directions, next
nearest (NNN) neighbour interaction $J_D$ and the ring exchange interaction $K$
on the square lattice. We calculate the thermodynamic quantities: Zero
temperature spin stiffness, internal energy, specific heat and the
magnetization. Using the diagonalized Hamiltonian, we show that no soft modes
develop when $\eta + \lambda >0 $, where $\eta = J^{\prime}/J$ and $\lambda =
K/J$. We further show that anisotropy ($\eta =2$) decreases the spin stiffness
by 5.7% of its isotropic ($\eta =1$) maximum value for some values of $\lambda$
and $\delta = J_D/J$. A similar reduction shows up in the magnetization. The
plot of the stiffness against $\eta (\lambda)$ reaches a maximum at
$\eta=0(\lambda =0)$ for specific values of $\delta$ and decreases rapidly as
it approaches $\eta + \lambda + 1=0$. In general, the supersolid phase
transition suggested earlier\cite{H} will occur in the regime $\eta + \lambda
+1 <0$.


title: Steady fluid flow in fissured porous media with imperfect contact

abstract:
  In this paper, periodic homogenization of a steady fluid flow in fissured
porous solids with imperfect interfacial contact is performed via two-scale
asymptotic method.


title:
Supersymmetry algebra cohomology IV: Primitive elements in all
  dimensions from D=4 to D=11

abstract:
  The primitive elements of the supersymmetry algebra cohomology as defined in
previous work are derived for standard supersymmetry algebras in dimensions
D=5,...,11 for all signatures of the related Clifford algebras of gamma
matrices and all numbers of supersymmetries. The results are presented in a
uniform notation along with results of previous work for D=4, and derived by
means of dimensional extension from D=4 up to D=11.


title: The extended narrow-line region of two type-I quasi-stellar objects

abstract:
  We investigate the narrow-line region (NLR) of two radio-quiet QSOs,
PG1012+008 and PG1307+085, using high signal-to-noise spatially resolved
long-slit spectra obtained with FORS1 at the Very Large Telescope. Although the
emission is dominated by the point-spread function of the nuclear source, we
are able to detect extended NLR emission out to several kpc scales in both QSOs
by subtracting the scaled central spectrum from outer spectra. In contrast to
the nuclear spectrum, which shows a prominent blue wing and a broad line
profile of the [O III] line, the extended emission reveals no clear signs of
large scale outflows. Exploiting the wide wavelength range, we determine the
radial change of the gas properties in the NLR, i.e., gas temperature, density,
and ionization parameter, and compare them with those of Seyfert galaxies and
type-II QSOs. The QSOs have higher nuclear temperature and lower electron
density than Seyferts, but show no significant difference compared to type-II
QSOs, while the ionization parameter decreases with radial distance, similar to
the case of Seyfert galaxies. For PG1012+008, we determine the stellar velocity
dispersion of the host galaxy. Combined with the black hole mass, we find that
the luminous radio-quiet QSO follows the local M_BH-sigma* relation of active
galactic nuclei.


title: Lovelock theory, black holes and holography

abstract:
  Lovelock theory is the natural extension of general relativity to higher
dimensions. It can be also thought of as a toy model for ghost-free higher
curvature gravity. It admits a family of AdS vacua, most (but not all) of them
supporting black holes that display interesting features. This provides an
appealing arena to explore different holographic aspects in the context of the
AdS/CFT correspondence.


title:
A note on the subadditivity problem for maximal shifts in free
  resolutions

abstract:
  We present some partial results regarding subadditivity of maximal shifts in
finite graded free resolutions.


title:
Kelvin-Helmholtz instability in a current-vortex sheet at a 3D magnetic
  null

abstract:
  We report here, for the first time, an observed instability of a
Kelvin-Helmholtz (KH) nature occurring in a fully three-dimensional (3D)
current-vortex sheet at the fan plane of a 3D magnetic null point. The
current-vortex layer forms self-consistently in response to foot point driving
around the spine lines of the null. The layer first becomes unstable at an
intermediate distance from the null point, with the instability being
characterized by a rippling of the fan surface and a filamentation of the
current density and vorticity in the shear layer. Owing to the 3D geometry of
the shear layer, a branching of the current filaments and vortices is observed.
The instability results in a mixing of plasma between the two topologically
distinct regions of magnetic flux on either side of the fan separatrix surface,
as flux is reconnected across this surface. We make a preliminary investigation
of the scaling of the system with the dissipation parameters. Our results
indicate that the fan plane separatrix surface is an ideal candidate for the
formation of current-vortex sheets in complex magnetic fields and, therefore,
the enhanced heating and connectivity change associated with the instabilities
of such layers.


title:
Superconductivity induced by electron doping in the system La1-xMxOBiS2
  (M = Ti, Zr, Hf, Th)

abstract:
  We report a strategy to induce superconductivity in the BiS$_2$-based
compound LaOBiS$_2$. Instead of substituting F for O, we increase the
charge-carrier density (electron dope) via substitution of tetravalent
Th$^{+4}$, Hf$^{+4}$, Zr$^{+4}$, and Ti$^{+4}$ for trivalent La$^{+3}$. It is
found that both the LaOBiS$_2$ and ThOBiS$_2$ parent compounds are bad metals
and that superconductivity is induced by electron doping with \emph{T$_c$}
values of up to 2.85 K. The superconducting and normal states were
characterized by electrical resistivity, magnetic susceptibility, and heat
capacity measurements. We also demonstrate that reducing the charge-carrier
density (hole doping) via substitution of divalent Sr$^{+2}$ for La$^{+3}$ does
not induce superconductivity.


title: Quench cooling under reduced gravity

abstract:
  We report the quench cooling experiments performed with liquid O2 under
different levels of gravity simulated with the magnetic gravity compensation. A
copper disk is quenched from 270K to 90K. It is found that the cooling time in
microgravity is very long in comparison with any other gravity level. This
phenomenon is explained by the isolation effect of the gas surrounding the
disk. The liquid subcooling is shown to drastically improuve the heat exchange
thus reducing the cooling time (about 20 times). The effect of subcooling on
the heat transfer is analyzed at different gravity levels. It is shown that
such type of experiments cannot be used for the analysis of the critical heat
flux (CHF) of the boiling crisis. The minimum heat flux (MHF) of boiling is
analyzed instead.


title:
Prototyping non-equilibrium viscous-timescale accretion theory using LMC
  X-3

abstract:
  Explaining variability observed in the accretion flows of black hole X-ray
binary systems remains challenging, especially concerning timescales less than,
or comparable to, the viscous timescale but much larger than the inner orbital
period despite decades of research identifying numerous relevant physical
mechanisms. We take a simplified but broad approach to study several mechanisms
likely relevant to patterns of variability observed in the persistently
high-soft Roche-lobe overflow system LMC X-3. Based on simple estimates and
upper bounds, we find that physics beyond varying disk/corona bifurcation at
the disk edge, Compton-heated winds, modulation of total supply rate via
irradiation of the companion, and the likely extent of the partial hydrogen
ionization instability is needed to explain the degree, and especially the
pattern, of variability in LMC X-3 largely due to viscous dampening. We then
show how evaporation--condensation may resolve or compound the problem given
the uncertainties associated with this complex mechanism and our current
implementation. We briefly mention our plans to resolve the question, refine
and extend our model, and alternatives we have not yet explored.


title: On the U(1) duality anomaly and the S-matrix of N=4 supergravity

abstract:
  N=4 Poincare supergravity has a global SU(1,1) duality symmetry that acts
manifestly only on shell as it involves duality rotations of vector fields. A
U(1) subgroup of this symmetry is known to be anomalous at the quantum level in
the presence of a non-trivial gravitational background. We first derive this
anomaly from a novel perspective, by relating it to a similar anomaly in
conformal supergravity where SU(1,1) acts off shell, using the fact that N=4
Poincare supergravity has a superconformal formulation. We explicitly construct
the corresponding local and nonlocal anomalous terms in the one-loop effective
action. We then study how this anomaly is reflected in the supergravity
S-matrix. Calculating one-loop N=4 supergravity scattering amplitudes (with and
without additional matter multiplets) using color/kinematics duality and the
double-copy construction we find that a particular U(1) symmetry which was
present in the tree-level amplitudes is broken at the quantum level. This
breaking manifests itself in the appearance of new one-loop N=4 supergravity
amplitudes that have non-vanishing soft-scalar limits (these amplitudes are
absent in N>4 supergravities). We discuss the relation between these
symmetry-violating amplitudes and the corresponding U(1) anomalous term in the
one-loop supergravity effective action.


title: Liquid crystal elastomers and phase transitions in rod networks

abstract:
  In this article, we construct and analyze models of anisotropic crosslinked
polymers employing tools from the theory of liquid crystal elastomers. The
anisotropy of these systems stems from the presence of rigid-rod molecular
units in the network. We study minimization of the energy for incompressible as
well as compressible materials, combining methods of isotropic nonlinear
elasticity with the theory of lyotropic liquid crystals. We apply our results
to the study of phase transitions in networks of rigid rods, in order to model
the behavior of actin filament systems found in the cytoskeleton.


title: Flexoelectric switching in cholesteric blue phases

abstract:
  We present computer simulations of the response of a flexoelectric blue phase
network, either in bulk or under confinement, to an applied field. We find a
transition in the bulk between the blue phase I disclination network and a
parallel array of disclinations along the direction of the applied field. Upon
switching off the field, the system is unable to reconstruct the original blue
phase but gets stuck in a metastable phase. Blue phase II is comparatively much
less affected by the field. In confined samples, the anchoring at the walls and
the geometry of the device lead to the stabilisation of further structures,
including field-aligned disclination loops, splayed nematic patterns, and yet
more metastable states. Our results are relevant to the understanding of the
switching dynamics for a class of new, "superstable", blue phases which are
composed of bimesogenic liquid crystals, as these materials combine anomalously
large flexoelectric coefficients, and low or near-zero dielectric anisotropy.


title: Phase transitions in general gravity theories

abstract:
  Phase transitions between two competing vacua of a given theory are quite
common in physics. We discuss how to construct the space-time solutions that
allow the description of phase transitions between different branches (or
asymptotics) of a given higher curvature gravity theory at finite temperature.


title: Random Intersection Trees

abstract:
  Finding interactions between variables in large and high-dimensional datasets
is often a serious computational challenge. Most approaches build up
interaction sets incrementally, adding variables in a greedy fashion. The
drawback is that potentially informative high-order interactions may be
overlooked. Here, we propose at an alternative approach for classification
problems with binary predictor variables, called Random Intersection Trees. It
works by starting with a maximal interaction that includes all variables, and
then gradually removing variables if they fail to appear in randomly chosen
observations of a class of interest. We show that informative interactions are
retained with high probability, and the computational complexity of our
procedure is of order $p^\kappa$ for a value of $\kappa$ that can reach values
as low as 1 for very sparse data; in many more general settings, it will still
beat the exponent $s$ obtained when using a brute force search constrained to
order $s$ interactions. In addition, by using some new ideas based on min-wise
hash schemes, we are able to further reduce the computational cost.
Interactions found by our algorithm can be used for predictive modelling in
various forms, but they are also often of interest in their own right as useful
characterisations of what distinguishes a certain class from others.


title: Limited benefit of cooperation in distributed relative localization

abstract:
  Important applications in robotic and sensor networks require distributed
algorithms to solve the so-called relative localization problem: a node-indexed
vector has to be reconstructed from measurements of differences between
neighbor nodes. In a recent note, we have studied the estimation error of a
popular gradient descent algorithm showing that the mean square error has a
minimum at a finite time, after which the performance worsens. This paper
proposes a suitable modification of this algorithm incorporating more realistic
"a priori" information on the position. The new algorithm presents a
performance monotonically decreasing to the optimal one. Furthermore, we show
that the optimal performance is approximated, up to a 1 + \eps factor, within a
time which is independent of the graph and of the number of nodes. This
convergence time is very much related to the minimum exhibited by the previous
algorithm and both lead to the following conclusion: in the presence of noisy
data, cooperation is only useful till a certain limit.


title: Canonoid transformations and master symmetries

abstract:
  Different types of transformations of a dynamical system, that are compatible
with the Hamiltonian structure, are discussed making use of a geometric
formalism. Firstly, the case of canonoid transformations is studied with great
detail and then the properties of master symmetries are also analyzed. The
relations between the existence of constants of motion and the properties of
canonoid symmetries is discussed making use of a family of boundary and
coboundary operators.


title:
Multiparty quantum communication using multiqubit entanglement and
  teleportation

abstract:
  We propose a 2N qubit entangled channel that can be used to teleport N qubits
in a network to a single receiver. We describe the construction of this channel
and explicitly demonstrate how the protocol works. The protocol is different
from teleportation using $N$ Bell pairs shared between $N$ senders and a single
receiver, as it ensures that all parties have to participate in order for the
teleportation to be successful. This can be advantageous in various scenarios
and we discuss potential application of this protocol to voting.


title:
The Convergence of eQTL Mapping, Heritability Estimation and Polygenic
  Modeling: Emerging Spectrum of Risk Variation in Bipolar Disorder

abstract:
  It is widely held that a substantial genetic component underlies Bipolar
Disorder (BD) and other neuropsychiatric disease traits. Recent efforts have
been aimed at understanding the genetic basis of disease susceptibility, with
genome-wide association studies (GWAS) unveiling some promising associations.
Nevertheless, the genetic etiology of BD remains elusive with a substantial
proportion of the heritability - which has been estimated to be 80% based on
twin and family studies - unaccounted for by the specific genetic variants
identified by large-scale GWAS. Furthermore, functional understanding of
associated loci generally lags discovery. Studies we report here provide
considerable support to the claim that substantially more remains to be gained
from GWAS on the genetic mechanisms underlying BD susceptibility, and that a
large proportion of the variation in disease risk may be uncovered through
integrative functional genomic approaches. We combine recent analytic advances
in heritability estimation and polygenic modeling and leverage recent
technological advances in the generation of -omics data to evaluate the nature
and scale of the contribution of functional classes of genetic variation to a
relatively intractable disorder. We identified cis eQTLs in cerebellum and
parietal cortex that capture more than half of the total heritability
attributable to SNPs interrogated through GWAS and showed that eQTL-based
heritability estimation is highly tissue-dependent. Our findings show that a
much greater resolution may be attained than has been reported thus far on the
number of common loci that capture a substantial proportion of the heritability
to disease risk and that the functional nature of contributory loci may be
clarified en masse.