title:
Influence of Inter-Layer Exchanges on Vorticity-Aligned Colloidal String
  Assembly in a Simple Shear Flow

abstract:
  Hard spheres in Newtonian fluids serve as paradigms for Non-Newtonian
materials phenomena exhibited by colloidal suspensions. A recent experimental
study (Cheng et al. 2011 Science, 333, 1276) showed that upon application of
shear to such a system, the particles form string-like structures aligned in
the vorticity direction. We explore the mechanism underlying this
out-of-equilibrium organization with Steered Transition Path Sampling, which
allows us to bias the Brownian contribution to rotations of close pairs of
particles and alter the dynamics of the suspension in a controlled fashion. Our
results show a strong correlation between the string structures and the
rotation dynamics. Specifically, the simulations show that accelerating the
rotations of close pairs of particles, not increasing their frequency, favors
formation of the strings. This insight delineates the roles of hydrodynamics,
Brownian motion, and particle packing, and, in turn, informs design strategies
for controlling the assembly of large-scale particle structures.


title:
Influence of Dielectric Environment on Role of Spin-Orbit Interaction
  for Image Potentials

abstract:
  We present a formalism for calculating the image potential for a
two-dimensional electron gas (2DEG) with Rashba spin-orbit interaction (SOI) as
well as for a 2D topological insulator (TI). The formalism is further
generalized for including the Coulomb coupled multiple layers. Roles of broken
inversion symmetry near the surface and the dielectric environment are
investigated by using a surface-response function. The insignificant role of
SOI in 2DEG is dramatically enhanced in TI by selecting a small relative
permittivity $\epsilon_b$ for the dielectric environment. Manipulating
$\epsilon_b$ is proven to provide an efficient way to drive electrons with
opposite spins into two different integral quantum Hall states. The prediction
made in this paper is expected to be experimentally observable for a 2DTI
system, such as Bi$_2$Se$_3$, with a helical spin behavior and a dominant
linear Rashba SOI-like term in the energy dispersion.


title:
On the uniqueness of the limit for an asymptotically autonomous
  semilinear equation on R^N

abstract:
  We consider a parabolic equation of the form u_t=\Delta u +f(u)+h(x,t) in
R^N\times (0,\infty), where f in C^1(R) is such that f(0)=0 and f'(0)<0 and h
is a suitable function on R^N\times (0,\infty). We show that under certain
conditions, each globally defined and nonnegative bounded solution u converges
to a single steady state.


title:
The parallel logic gates in synthetic gene networks induced by
  non-Gausssian noise

abstract:
  The newly appeared idea of Logical Stochastic Resonance (LSR) is verified in
synthetic gene networks induced by non-Gaussian noise. We realize the switching
between two kinds of logic gates under optimal moderate noise intensity by
varying two different tunable parameters in a single gene network. Furthermore,
in order to obtain more logic operations, thus providing additional information
processing capacity, we obtain in a two-dimensional toggle switch model two
complementary logic gates and realize the transformation between two logic
gates via the methods of changing different parameters. These simulated results
contribute to improve the computational power and functionality of the
networks.


title:
The two-point resistance of a resistor network: A new formulation and
  application to the cobweb network

abstract:
  We consider the problem of two-point resistance in a resistor network
previously studied by one of us [F. Y. Wu, J. Phys. A {\bf 37}, 6653 (2004)].
By formulating the problem differently, we obtain a new expression for the
two-point resistance between two arbitrary nodes which is simpler and can be
easier to use in practice. We apply the new formulation to the cobweb resistor
network to obtain the resistance between two nodes in the network.
Particularly, our results prove a recently proposed conjecture on the
resistance between the center node and a node on the network boundary. Our
analysis also solves the spanning tree problem on the cobweb network.


title: Experimental validation of XRF inversion code for Chandrayaan-1

abstract:
  We have developed an algorithm (x2abundance) to derive the lunar surface
chemistry from X-ray fluorescence (XRF) data for the Chandrayaan-1 X-ray
Spectrometer (C1XS) experiment. The algorithm converts the observed XRF line
fluxes to elemental abundances with uncertainties. We validated the algorithm
in the laboratory using high Z elements (20 < Z < 30) published in Athiray et
al. (2013). In this paper, we complete the exercise of validation using samples
containing low Z elements, which are also analogous to the lunar surface
composition (ie., contains major elements between 11 < Z < 30). The paper
summarizes results from XRF experiments performed on Lunar simulant (JSC-1A)
and anorthosite using a synchrotron beam excitation. We also discuss results
from the validation of x2abundance using Monte Carlo simulation (GEANT4 XRF
simulation).


title:
The Inviscid, Compressible and Rotational, 2D Isotropic Burgers and
  Pressureless Euler-Coriolis Fluids; Solvable models with illustrations

abstract:
  The coupling between dilatation and vorticity, two coexisting and fundamental
processes in fluid dynamics is investigated here, in the simplest cases of
inviscid 2D isotropic Burgers and pressureless Euler-Coriolis fluids
respectively modeled by single vortices confined in compressible, local,
inertial and global, rotating, environments. The field equations are
established, inductively, starting from the equations of the characteristics
solved with an initial Helmholtz decomposition of the velocity fields namely a
vorticity free and a divergence free part and, deductively, by means of a
canonical Hamiltonian Clebsch like formalism, implying two pairs of conjugate
variables. Two vector valued fields are constants of the motion: the velocity
field in the Burgers case and the momentum field per unit mass in the
Euler-Coriolis one. Taking advantage of this property, a class of solutions for
the mass densities of the fluids is given by the Jacobian of their sum with
respect to the actual coordinates. Implementation of the isotropy hypothesis
results in the cancellation of the dilatation-rotational cross terms in the
Jacobian. A simple expression is obtained for all the radially symmetric
Jacobians occurring in the theory. Representative examples of regular and
singular solutions are shown and the competition between dilatation and
vorticity is illustrated. Inspired by thermodynamical, mean field theoretical
analogies, a genuine variational formula is proposed which yields unique
measure solutions for the radially symmetric fluid densities investigated. We
stress that this variational formula, unlike the Hopf-Lax formula, enables us
to treat systems which are both compressible and rotational. Moreover in the
one-dimensional case, we show for an interesting application that both
variational formulas are equivalent.


title:
Stability of Boolean networks: The joint effects of topology and update
  rules

abstract:
  We study the stability of orbits in large Boolean networks with given complex
topology. We impose no restrictions on the form of the update rules, which may
be correlated with local topological properties of the network. While recent
past work has addressed the separate effects of nontrivial network topology and
certain special classes of update rules on stability, only crude results exist
about how these effects interact. We present a widely applicable solution to
this problem. Numerical experiments confirm our theory and show that local
correlations between topology and update rules can have profound effects on the
qualitative behavior of these systems.


title: Quantum Annealing and Computation: A Brief Documentary Note

abstract:
  Major breakthrough in quantum computation has recently been achieved using
quantum annealing to develop analog quantum computers instead of gate based
computers. After a short introduction to quantum computation, we retrace very
briefly the history of these developments and discuss the Indian researches in
this connection and provide some interesting documents (in the Figs.) obtained
from a chosen set of high impact papers (and also some recent news etc. blogs
appearing in the Internet). This note is also designed to supplement an earlier
note by Bose (Science and Culture, 79, pp. 337-378, 2013).


title:
Momentum imbalance of D mesons in ultra-relativistic heavy-ion
  collisions at LHC

abstract:
  As a new observable for heavy flavor correlations the momentum imbalance
$A_D$ of D mesons is proposed. It is defined analogously to the jet momentum
imbalance $A_J$ of fully reconstructed jets. However, since D mesons are flavor
tagged particles, no jet reconstruction is necessary. $A_D$ quantifies the
influence of the medium created in heavy-ion collisions on correlated charm
pairs. We present results with the partonic transport model Boltzmann Approach
to MultiParton Scatterings (BAMPS), which describes well the nuclear
modification factor and elliptic flow of all heavy flavor particles at RHIC and
LHC. The $A_D$ distribution in heavy-ion collisions at LHC is shifted to larger
values of $A_D$ compared to proton-proton collisions. We argue that this shift
is due to medium effects and can be explained partially by a path length
imbalance of charm pairs and partially by momentum fluctuations in the initial
charm pair distribution.


title: Director Field Model of the Primary Visual Cortex for Contour Detection

abstract:
  We aim to build the simplest possible model capable of detecting long, noisy
contours in a cluttered visual scene. For this, we model the neural dynamics in
the primate primary visual cortex in terms of a continuous director field that
describes the average rate and the average orientational preference of active
neurons at a particular point in the cortex. We then use a linear-nonlinear
dynamical model with long range connectivity patterns to enforce long-range
statistical context present in the analyzed images. The resulting model has
substantially fewer degrees of freedom than traditional models, and yet it can
distinguish large contiguous objects from the background clutter by suppressing
the clutter and by filling-in occluded elements of object contours. This
results in high-precision, high-recall detection of large objects in cluttered
scenes. Parenthetically, our model has a direct correspondence with the Landau
- de Gennes theory of nematic liquid crystal in two dimensions.


title:
Estimating the FDI Impact on Economic Growth and Export Performances of
  the European Economies in Transition

abstract:
  Within the last two decades, Foreign Direct Investment (FDI) has been
observed as one of the prime instruments in the process of restructuring the
European economies in transition. Many scholars argue that FDI is expected to
be a source of valuable technology transfer thus might certainly have positive
effects on host country development efforts. Nonetheless, there are no
clear-cut findings about the FDI genuine performances in supporting the
economic growth, productivity and export improvements within the European
transition countries. Using a large and comprehensive data set, we will
therefore analyze the linkage between FDI and above mentioned variables, so as
to recommend national policy appropriate measures aimed at averting negative
and strengthening the positive FDI spillovers.


title:
Vibronic phenomena and exciton-vibrational interference in
  two-dimensional spectra of molecular aggregates

abstract:
  A general theory of electronic excitations in aggregates of molecules coupled
to intramolecular vibrations and the harmonic environment is developed for
simulation of the third-order nonlinear spectroscopy signals. The model is
applied in studies of the time-resolved two-dimensional coherent spectra of
four characteristic model systems: weakly / strongly vibronically coupled
molecular dimers coupled to high / low frequency intramolecular vibrations. The
results allow us to classify the typical spectroscopic features as well as to
define the limiting cases, when the long-lived quantum coherences are present
due to vibrational lifetime borrowing, when the complete exciton-vibronic
mixing occurs and when separation of excitonic and vibrational coherences is
proper.


title:
Numerical verification of the existence of localization of the elastic
  energy for closely spaced rigid disks

abstract:
  The problem of determining the thermomechanical characteristics of the system
of closely spaced bodies considered by many authors. For scalar problems, such
as problems of heat, electrostatic, etc., the localization effect was found (so
called Tamm's shielding effect), which consists in the fact that in a system of
closely spaced highly conductive bodies, most energy is localized in the region
between adjacent bodies. We can assume that the localization of energy is a
general property of closely spaced bodies. The aim is to study the effect of
localization of energy in a system of closely spaced rigid bodies in an elastic
medium.


title: Domination subdivision and domination multisubdivision numbers of graphs

abstract:
  The \emph{domination subdivision number} sd$(G)$ of a graph $G$ is the
minimum number of edges that must be subdivided (where an edge can be
subdivided at most once) in order to increase the domination number of $G$. It
has been shown \cite{vel} that sd$(T)\leq 3$ for any tree $T$. We prove that
the decision problem of the domination subdivision number is NP-complete even
for bipartite graphs. For this reason we define the \emph{domination
multisubdivision number} of a nonempty graph $G$ as a minimum positive integer
$k$ such that there exists an edge which must be subdivided $k$ times to
increase the domination number of $G$. We show that msd$(G)\leq 3$ for any
graph $G$. The domination subdivision number and the domination
multisubdivision numer of a graph are incomparable in general case, but we show
that for trees these two parameters are equal. We also determine domination
multisubdivision number for some classes of graphs.


title: Half-integral finite surgeries on knots in $S^3$

abstract:
  Suppose that a hyperbolic knot in $S^3$ admits a finite surgery, Boyer and
Zhang proved that the surgery slope must be either integral or half-integral,
and they conjectured that the latter case does not happen. Using the correction
terms in Heegaard Floer homology, we prove that if a hyperbolic knot in $S^3$
admits a half-integral finite surgery, then the knot must have the same knot
Floer homology as one of eight non-hyperbolic knots which are known to admit
such surgeries, and the resulting manifold must be one of ten spherical space
forms. As knot Floer homology carries a lot of information about the knot, this
gives a strong evidence to Boyer--Zhang's conjecture.


title:
Demonstration of a novel focusing small-angle neutron scattering
  instrument equipped with axisymmetric mirrors

abstract:
  Small-angle neutron scattering (SANS) is the most significant neutron
technique in terms of impact on science and engineering. However, the basic
concept of SANS facilities has not changed since the technique's inception
about 40 years ago, as all SANS instruments, save a few, are still designed as
pinhole cameras. Here we demonstrate a novel concept for a SANS instrument,
based on axisymmetric focusing mirrors. We build and test a small prototype,
which shows a performance comparable to that of conventional large SANS
facilities. By using a detector with 50-micron pixels, we build the most
compact SANS instrument in the world. This work, together with the recent
demonstration that such mirrors could increase the signal rate at least
50-fold, while improving resolution, paves the way to novel SANS instruments,
thus affecting a broad community of scientists and engineers.


title: On a foliation-covariant elliptic operator on null hypersurfaces

abstract:
  We introduce a new elliptic operator on null hypersurfaces of
four-dimensional Lorentzian manifolds. This operator depends on the first and
second fundamental forms of the sections of a foliation of the null
hypersurface and its novelty originates from its covariant transformation under
change of foliation. It thus provides at any point an elliptic structure
intimately connected with the geometry of the null hypersurface, independent of
the choice of a specific section through that point. No analytic or algebraic
symmetries or other conditions are imposed on the metric. The spectral
properties of this elliptic operator are relevant to the evolution of the wave
equation, and in particular, the existence of conservation laws along null
hypersurfaces.


title:
Measurement of the cross section and angular correlations for associated
  production of a Z boson with b hadrons in pp collisions at sqrt(s) = 7 TeV

abstract:
  A study of proton-proton collisions in which two b hadrons are produced in
association with a Z boson is reported. The collisions were recorded at a
centre-of-mass energy of 7 TeV with the CMS detector at the LHC, for an
integrated luminosity of 5.2 inverse femtobarns. The b hadrons are identified
by means of displaced secondary vertices, without the use of reconstructed
jets, permitting the study of b-hadron pair production at small angular
separation. Differential cross sections are presented as a function of the
angular separation of the b hadrons and the Z boson. In addition, inclusive
measurements are presented. For both the inclusive and differential studies,
different ranges of Z boson momentum are considered, and each measurement is
compared to the predictions from different event generators at leading-order
and next-to-leading-order accuracy.


title:
Test of the He-McKellar-Wilkens topological phase by atom
  interferometry. Part I: theoretical discussion

abstract:
  We have recently tested the topological phase predicted by He and McKellar
and by Wilkens: this phase appears when an electric dipole propagates in a
transverse magnetic field. In the present paper, we first recall the physical
origin of this phase and its relations to the Aharononov-Bohm and
Aharonov-Casher phases. We then explain possible detection schemes and we
briefly describe the lithium atom interferometer we have used for this purpose.
Finally, we analyze in great detail the phase shifts induced by electric and
magnetic fields acting on such an interferometer, taking into account
experimental defects. The experiment and its results are described in a
companion paper.


title: New Conditions for Sparse Phase Retrieval

abstract:
  We consider the problem of sparse phase retrieval, where a $k$-sparse signal
${\bf x} \in {\mathbb R}^n \textrm{ (or } {\mathbb C}^n\textrm{)}$ is measured
as ${\bf y} = |{\bf Ax}|,$ where ${\bf A} \in {\mathbb R}^{m \times n} \textrm{
(or } {\mathbb C}^{m \times n}\textrm{ respectively)}$ is a measurement matrix
and $|\cdot|$ is the element-wise absolute value. For a real signal and a real
measurement matrix ${\bf A}$, we show that $m = 2k$ measurements are necessary
and sufficient to recover ${\bf x}$ uniquely. For complex signal ${\bf x} \in
{\mathbb C}^n$ and ${\bf A} \in {\mathbb C}^{m \times n}$, we show that $m =
4k-2$ phaseless measurements are sufficient to recover ${\bf x}$. It is known
that the multiplying constant $4$ in $m = 4k-2$ cannot be improved.


title:
Scattering for nonlinear Schrodinger equation under partial harmonic
  confinement

abstract:
  We consider the nonlinear Schrodinger equation under a partial quadratic
confinement. We show that the global dispersion corresponding to the
direction(s) with no potential is enough to prove global in time Strichartz
estimates, from which we infer the existence of wave operators thanks to
suitable vector-fields. Conversely, given an initial Cauchy datum, the solution
is global in time and asymptotically free, provided that confinement affects
one spatial direction only. This stems from anisotropic Morawetz estimates,
involving a marginal of the position density.


title: Isomorphisms of quotients of FDD-algebras

abstract:
  We consider isomorphisms between quotient algebras of $\prod_{n=0}^{\infty}
\mathbb{M}_{k(n)}(\mathbb{C})$ associated with Borel ideals on $\mathbb{N}$ and
prove that it is relatively consistent with \textbf{ZFC} that all of these
isomorphisms are trivial, in the sense that they lift to a *-homomorphism from
$\prod_{n=0}^{\infty} \mathbb{M}_{k(n)}(\mathbb{C})$ into itself. This
generalizes a result of Farah-Shelah who proved this result for centers of
these algebras (in its dual form). We also use a simpler forcing notion and
completely remove the large cardinal assumption used by Farah-Shelah.


title: Oscillating supertubes and neutral rotating black hole microstates

abstract:
  The construction of neutral black hole microstates is an important problem,
with implications for the information paradox. In this paper we conjecture a
construction of non-supersymmetric supergravity solutions describing D-brane
configurations which carry mass and angular momentum, but no other conserved
charges. We first study a classical string solution which locally carries
dipole winding and momentum charges in two compact directions, but globally
carries no net winding or momentum charge. We investigate its backreaction in
the D1-D5 duality frame, where this object becomes a supertube which locally
carries oscillating dipole D1-D5 and NS1-NS5 charges, and again carries no net
charge. In the limit of an infinite straight supertube, we find an exact
supergravity solution describing this object. We conjecture that a similar
construction may be carried out based on a class of two-charge
non-supersymmetric D1-D5 solutions. These results are a step towards
demonstrating how neutral black hole microstates may be constructed in string
theory.


title:
Existence and regularity of solution for a Stochastic
  Cahn-Hilliard/Allen-Cahn equation with unbounded noise diffusion

abstract:
  The Cahn-Hilliard/Allen-Cahn equation with noise is a simplified mean field
model of stochastic microscopic dynamics associated with adsorption and
desorption-spin flip mechanisms in the context of surface processes. For such
an equation we consider a multiplicative space-time white noise with diffusion
coefficient of sub-linear growth. Using technics from semigroup theory, we
prove existence, and path regularity of stochastic solution depending on that
of the initial condition. Our results are also valid for the stochastic
Cahn-Hilliard equation with unbounded noise diffusion, for which previous
results were established only in the framework of a bounded diffusion
coefficient. We prove that the path regularity of stochastic solution depends
on that of the initial condition, and are identical to those proved for the
stochastic Cahn-Hilliard equation and a bounded noise diffusion coefficient. If
the initial condition vanishes, they are strictly less than 2-d/2 in space and
1/2-d/8 in time. As expected from the theory of parabolic operators in the
sense of Petrovski, the bi-Laplacian operator seems to be dominant in the
combined model.


title: Faber polynomials of matrices for non-convex sets

abstract:
  It has been recently shown that $|| F_n(A) ||\leq 2$, where $A$ is a linear
continuous operator acting in a Hilbert space, and $F_n$ is the Faber
polynomial of degree $n$ corresponding to some convex compact $E\subset \mathbb
C$ containing the numerical range of $A$. Such an inequality is useful in
numerical linear algebra, it allows for instance to derive error bounds for
Krylov subspace methods. In the present paper we extend this result to not
necessary convex sets $E$.


title: Counting the Angels and Devils in Escher's Circle Limit IV

abstract:
  We derive the rational generating function that enumerates the angels and
devils in M. C. Escher's {\it Circle Limit IV} according to their combinatorial
distance from the six creatures whose feet meet at the center of the disk. This
result shows that the base of the exponential rate of growth is $1.582\ldots$
(the largest root of the polynomial $1 - z^2 - 2z^3 - z^4 + z^6$).


title:
Singularity Confinement and Projective Resolution of Triangulated
  Category

abstract:
  We proposed, in our previous paper, to characterize the Hirota-Miwa equation
by means of the theory of triangulated category. We extend our argument in this
paper to support the idea. In particular we show in detail how the singularity
confinement, a phenomenon which was proposed to characterize integrable maps,
can be associated with the projective resolution of the triangulated category.


title: A sandpile model for proportionate growth

abstract:
  An interesting feature of growth in animals is that different parts of the
body grow at approximately the same rate. This property is called proportionate
growth. In this paper, we review our recent work on patterns formed by adding
$N$ grains at a single site in the abelian sandpile model. These simple models
show very intricate patterns, show proportionate growth, and sometimes having a
striking resemblance to natural forms. We give several examples of such
patterns. We discuss the special cases where the asymptotic pattern can be
determined exactly. The effect of noise in the background or in the rules on
the patterns is also discussed.


title: The Intrinsic Extreme Ultraviolet Fluxes of F5 V to M5 V Stars

abstract:
  Extreme ultraviolet (EUV) radiations (10--117 nm) from host stars play
important roles in the ionization, heating, and mass loss from exoplanet
atmospheres. Together with the host star's Lyman-alpha and far-UV (117--170 nm)
radiation, EUV radiation photodissociates important molecules, thereby changing
the chemistry in exoplanet atmospheres. Since stellar EUV fluxes cannot now be
measured and interstellar neutral hydrogen completely obscures stellar
radiation between 40 and 91.2 nm, even for the nearest stars, we must estimate
the unobservable EUV flux by indirect methods. New non-LTE semiempirical models
of the solar chromosphere and corona and solar irradiance measurements show
that the ratio of EUV flux in a variety of wavelength bands to the Lyman-alpha
flux varies slowly with the Lyman-alpha flux and thus with the magnetic heating
rate. This suggests and we confirm that solar EUV/Lyman-alpha flux ratios based
on the models and observations are similar to the available 10--40 nm flux
ratios observed with the EUVE satellite and the 91.2--117 nm flux observed with
the FUSE satellite for F5 V--M5 V stars. We provide formulae for predicting EUV
flux ratios based on the EUVE and FUSE stellar data and on the solar models,
which are essential input for modelling the atmospheres of exoplanets.


title:
Mean of the $L^\infty$-norm for $L^2$-normalized random waves on compact
  aperiodic Riemannian manifolds

abstract:
  This article concerns upper bounds for $L^\infty$-norms of random approximate
eigenfunctions of the Laplace operator on a compact aperiodic Riemannian
manifold $(M,g).$ We study $f_{\lambda}$ chosen uniformly at random from the
space of $L^2$-normalized linear combinations of Laplace eigenfunctions with
eigenvalues in the interval $(\lambda^2, \lr{\lambda+1}^2].$ Our main result is
that the expected value of $\norm{f_\lambda}_\infty$ grows at most like $C
\sqrt{\log \lambda}$ as $\lambda \to \infty$, where $C$ is an explicit constant
depending only on the dimension and volume of $(M,g).$ In addition, we obtain
concentration of the $L^\infty$-norm around its mean and median and study the
analogous problems for Gaussian random waves on $(M,g).$


title: Complexity of linear circuits and geometry

abstract:
  We use algebraic geometry to study matrix rigidity, and more generally, the
complexity of computing a matrix-vector product, continuing a study initiated
by Kumar, et. al. We (i) exhibit many non-obvious equations testing for
(border) rigidity, (ii) compute degrees of varieties associated to rigidity,
(iii) describe algebraic varieties associated to families of matrices that are
expected to have super-linear rigidity, and (iv) prove results about the ideals
and degrees of cones that are of interest in their own right.


title:
Weakly supervised clustering: Learning fine-grained signals from coarse
  labels

abstract:
  Consider a classification problem where we do not have access to labels for
individual training examples, but only have average labels over subpopulations.
We give practical examples of this setup and show how such a classification
task can usefully be analyzed as a weakly supervised clustering problem. We
propose three approaches to solving the weakly supervised clustering problem,
including a latent variables model that performs well in our experiments. We
illustrate our methods on an analysis of aggregated elections data and an
industry data set that was the original motivation for this research.


title: The influence of the symmetry energy on the cone-azimuthal emission

abstract:
  In the framework of the isospin-dependent Boltzmann-Uehling-Uhlenbeck
transport model, effects of the symmetry energy on the evolutions of free n/p
ratio and charged pion ratio in the semi-central collision of
$^{197}$Au+$^{197}$Au at an incident beam energy of 400 MeV/nucleon are
studied. At the beginning of the reaction (before 11 fm/c) they are both
affected by the low-density behavior of the symmetry energy but soon after are
affected by the high-density behavior of the symmetry energy after nuclei are
compressed (after 11 fm/c) and the effects of the symmetry energy are generally
smaller compared with the central collision case. Interestingly, their
dependences on the symmetry energy are shown to arise with increase of
cone-azimuthal angle of the emitted particles. In the direction perpendicular
to the reaction plane, the $\pi^{-}/\pi ^{+}$ ratio or free n/p ratio
especially at high kinetic energies exhibits significant sensitivity to the
symmetry energy.


title:
The characteristic gluing problem and conservation laws for the wave
  equation on null hypersurfaces

abstract:
  We obtain necessary and sufficient conditions for the existence of
"conservation laws" on null hypersurfaces for the wave equation on general
four-dimensional Lorentzian manifolds. Examples of null hypersurfaces
exhibiting such conservation laws include the standard null cones of Minkowski
spacetime and the degenerate horizons of extremal black holes. Another
(limiting) example of such a conservation law is that which gives rise to the
well-known Newman-Penrose constants along the null infinity of asymptotically
flat spacetimes. The existence of such conservation laws can be viewed as an
obstruction to a certain gluing construction for characteristic initial data
for the wave equation. We initiate the general study of the latter gluing
problem and show that the existence of conservation laws is in fact the only
obstruction. Our method relies on a novel elliptic structure associated to a
foliation with 2-spheres of a null hypersurface.


title:
Collaboration networks from a large CV database: dynamics, topology and
  bonus impact

abstract:
  Understanding the dynamics of research production and collaboration may
reveal better strategies for scientific careers, academic institutions and
funding agencies. Here we propose the use of a large and multidisciplinar
database of scientific curricula in Brazil, namely, the Lattes Platform, to
study patterns of scientific production and collaboration. In this database,
detailed information about publications and researchers are made available by
themselves so that coauthorship is unambiguous and individuals can be evaluated
by scientific productivity, geographical location and field of expertise. Our
results show that the collaboration network is growing exponentially for the
last three decades, with a distribution of number of collaborators per
researcher that approaches a power-law as the network gets older. Moreover,
both the distributions of number of collaborators and production per researcher
obey power-law behaviors, regardless of the geographical location or field,
suggesting that the same universal mechanism might be responsible for network
growth and productivity.We also show that the collaboration network under
investigation displays a typical assortative mixing behavior, where teeming
researchers (i.e., with high degree) tend to collaborate with others alike.
Finally, our analysis reveals that the distinctive collaboration profile of
researchers awarded with governmental scholarships suggests a strong bonus
impact on their productivity.


title: Periodic Optical Variability of Radio Detected Ultracool Dwarfs

abstract:
  A fraction of very low mass stars and brown dwarfs are known to be radio
active, in some cases producing periodic pulses. Extensive studies of two such
objects have also revealed optical periodic variability and the nature of this
variability remains unclear. Here we report on multi-epoch optical photometric
monitoring of six radio detected dwarfs, spanning the $\sim$M8 - L3.5 spectral
range, conducted to investigate the ubiquity of periodic optical variability in
radio detected ultracool dwarfs. This survey is the most sensitive ground-based
study carried out to date in search of periodic optical variability from
late-type dwarfs, where we obtained 250 hours of monitoring, delivering
photometric precision as low as $\sim$0.15%. Five of the six targets exhibit
clear periodicity, in all cases likely associated with the rotation period of
the dwarf, with a marginal detection found for the sixth. Our data points to a
likely association between radio and optical periodic variability in
late-M/early-L dwarfs, although the underlying physical cause of this
correlation remains unclear. In one case, we have multiple epochs of monitoring
of the archetype of pulsing radio dwarfs, the M9 TVLM 513-46546, spanning a
period of 5 years, which is sufficiently stable in phase to allow us to
establish a period of 1.95958 $\pm$ 0.00005 hours. This phase stability may be
associated with a large-scale stable magnetic field, further strengthening the
correlation between radio activity and periodic optical variability. Finally,
we find a tentative spin-orbit alignment of one component of the very low mass
binary LP 349-25.


title: A note on random greedy coloring of uniform hypergraphs

abstract:
  The smallest number of edges forming an n-uniform hypergraph which is not
r-colorable is denoted by m(n,r). Erd\H{o}s and Lov\'{a}sz conjectured that
m(n,2)=\theta(n 2^n)$. The best known lower bound m(n,2)=\Omega(sqrt(n/log(n))
2^n) was obtained by Radhakrishnan and Srinivasan in 2000. We present a simple
proof of their result. The proof is based on analysis of random greedy coloring
algorithm investigated by Pluh\'ar in 2009. The proof method extends to the
case of r-coloring, and we show that for any fixed r we have
m(n,r)=\Omega((n/log(n))^(1-1/r) r^n) improving the bound of Kostochka from
2004. We also derive analogous bounds on minimum edge degree of an n-uniform
hypergraph that is not r-colorable.


title: Behavioral Strategy Chases Promote the Evolution of Prey Intelligence

abstract:
  Predator-prey coevolution is commonly thought to result in reciprocal arms
races that produce increasingly extreme and complex traits. However, such
directional change is not inevitable. Here, we provide evidence for a
previously undemonstrated dynamic that we call "strategy chases," wherein
populations explore strategies with similar levels of complexity, but differing
behaviorally. Indeed, in populations of evolving digital organisms, as prey
evolved more effective predator-avoidance strategies, they explored a wider
range of behavioral strategies in addition to exhibiting increased levels of
behavioral complexity. Furthermore, coevolved prey became more adept in
foraging, evidently through coopting components of explored sense-and-flee
avoidance strategies into sense-and-retrieve foraging strategies. Specifically,
we demonstrate that coevolution induced non-escalating exploration of
behavioral space, corresponding with significant evolutionary advancements,
including increasingly intelligent behavioral strategies.


title:
Magneto-thermoelectric current induced by phonon drag in low-dimensional
  junctions

abstract:
  We examine splitting the heat flow in a low-dimensional junction under
influence an external d.c. magnetic field. The junction is a crossing between
the narrow single atomic layer stripe (or a nanotube) of a semiconductor C with
a metal stripe N (C/N-knot). External source of heat injects the
non-equilibrium (NE) phonons, electrons, and holes into C which then propagate
in direction the C/N-knot. Most of the heat is carried by NE phonons which drag
additional electron and hole excitations along C. In vicinity the C/N-knot, the
Lorentz force pulls the charge carriers from C to N thus inducing a substantial
lateral magneto-thermoelectric electric current (MTEC) along N.


title:
Robust and highly performant ring detection algorithm for 3d particle
  tracking using 2d microscope imaging

abstract:
  Three-dimensional particle tracking is an essential tool in studying dynamics
under the microscope, namely, fluid dynamics in microfluidic devices, bacteria
taxis, cellular trafficking. The 3d position can be determined using 2d imaging
alone by measuring the diffraction rings generated by an out-of-focus
fluorescent particle, imaged on a single camera. Here I present a ring
detection algorithm exhibiting a high detection rate, which is robust to the
challenges arising from ring occlusion, inclusions and overlaps, and allows
resolving particles even when near to each other. It is capable of real time
analysis thanks to its high performance and low memory footprint. The proposed
algorithm, an offspring of the circle Hough transform, addresses the need to
efficiently trace the trajectories of many particles concurrently, when their
number in not necessarily fixed, by solving a classification problem, and
overcomes the challenges of finding local maxima in the complex parameter space
which results from ring clusters and noise. Several algorithmic concepts
introduced here can be advantageous in other cases, particularly when dealing
with noisy and sparse data. The implementation is based on open-source and
cross-platform software packages only, making it easy to distribute and modify.
It is implemented in a microfluidic experiment allowing real-time
multi-particle tracking at 70 Hz, achieving a detection rate which exceeds 94%
and only 1% false-detection.


title: Cascading gauge theory on dS_4 and String Theory Landscape

abstract:
  Placing anti-D3 branes at the tip of the conifold in Klebanov-Strassler
geometry provides a generic way of constructing meta-stable de Sitter (dS)
vacua in String Theory. A local geometry of such vacua exhibit gravitational
solutions with a D3 charge measured at the tip opposite to the asymptotic
charge. We discuss a restrictive set of such geometries, where anti-D3 branes
are smeared at the tip. Such geometries represent holographic dual of cascading
gauge theory in dS4 with or without chiral symmetry breaking. We find that in
the phase with unbroken chiral symmetry the D3 charge at the tip is always
positive. Furthermore, this charge is zero in the phase with spontaneously
broken chiral symmetry. We show that the effective potential of the chirally
symmetric phase is lower than that in the symmetry broken phase, i.e, there is
no spontaneous chiral symmetry breaking for cascading gauge theory in dS4. The
positivity of the D3 brane charge in smooth de-Sitter deformed conifold
geometries with fluxes presents difficulties in uplifting AdS vacua to dS ones
in String Theory via smeared anti-D3 branes.


title:
Real Space Imaging of the Verwey Transition at the (100) Surface of
  Magnetite

abstract:
  Effects of the Verwey transition on the (100) surface of magnetite were
studied using scanning tunelling microscopy and spin polarized low-energy
electron microsccopy. On cooling through the transition temperature Tv, the
initially flat surface undergoes a roof-like distortion with a periodicity of
~0.5 um due to ferroelastic twinning within monoclinic domains of the
low-temperature monoclinic structure. The monoclinic c axis orients in the
surface plane, along the [001]c directions. At the atomic scale, the
charge-ordered sqrt2xsqrt2R45 reconstruction of the (100) surface is
unperturbed by the bulk transition, and is continuous over the twin boundaries.
Time resolved low-energy electron microscopy movies reveal the structural
transition to be first-order at the surface, indicating that the bulk
transition is not an extension of the Verwey-like sqrt2xsqrt2R45
reconstruction. Although conceptually similar, the charge-ordered phases of the
(100) surface and sub-Tv bulk of magnetite are unrelated phenomena.


title: The minimal curvaton-higgs model

abstract:
  We present the first full study of the minimal curvaton-higgs (MCH) model,
which is a minimal interpretation of the curvaton scenario with one real scalar
coupled to the standard model Higgs boson. The standard model coupling allows
the dynamics of the model to be determined in detail, including effects from
the thermal background and from radiative corrections to the potential. The
relevant mechanisms for curvaton decay are incomplete non-perturbative decay
(delayed by thermal blocking), followed by decay via a dimension-5
non-renormalisable operator. To avoid spoiling the predictions of big bang
nucleosynthesis, we find the "bare" curvaton mass to be m_\sigma > 8 x 10^4
GeV. To match observational data from Planck there is an upper limit on the
curvaton-higgs coupling g, between 10^-3 and 10^-2, depending on the mass. This
is due to interactions with the thermal background. We find that typically
non-Gaussianities are small but that if fnl is observed in the near future then
m_\sigma < 5 x 10^9 GeV, depending on Hubble scale during inflation. In a
thermal dark matter model, the lower bound on m_\sigma\ can increase
substantially. The parameter space may also be affected once the baryogenesis
mechanism is specified.


title: Nucleon Form Factors and Distribution Amplitudes in QCD

abstract:
  We derive light-cone sum rules for the electromagnetic nucleon form factors
including the next-to-leading-order corrections for the contribution of
twist-three and twist-four operators and a consistent treatment of the nucleon
mass corrections. The essence of this approach is that soft Feynman
contributions are calculated in terms of small transverse distance quantities
using dispersion relations and duality. The form factors are thus expressed in
terms of nucleon wave functions at small transverse separations, called
distribution amplitudes, without any additional parameters. The distribution
amplitudes, therefore, can be extracted from the comparison with the
experimental data on form factors and compared to the results of lattice QCD
simulations. A selfconsistent picture emerges, with the three valence quarks
carrying 40%:30%:30% of the proton momentum.


title: Nonempty Intersection of Longest Paths in Series-Parallel Graphs

abstract:
  In 1966 Gallai asked whether all longest paths in a connected graph have
nonempty intersection. This is not true in general and various counterexamples
have been found. However, the answer to Gallai's question is positive for
several well-known classes of graphs, as for instance connected outerplanar
graphs, connected split graphs, and 2-trees. A graph is series-parallel if it
does not contain $K_4$ as a minor. Series-parallel graphs are also known as
partial 2-trees, which are arbitrary subgraphs of 2-trees. We present a proof
that every connected series-parallel graph has a vertex that is common to all
of its longest paths. Since 2-trees are maximal series-parallel graphs, and
outerplanar graphs are also series-parallel, our result captures these two
classes in one proof and strengthens them to a larger class of graphs. We also
describe how this vertex can be found in linear time.


title:
Design considerations for the cosmic-ray-veto system of the Mu2e
  experiment at Fermilab

abstract:
  Since the discovery of the muon, particle physicists have carried out a
series of experiments aimed at measuring flavor violation in charged-lepton
interactions. To date, no such violation has been observed. The Mu2e experiment
at Fermilab will search for the charged lepton flavor violating process of
coherent muon-to-electron conversion in the presence of a nucleus with a
sensitivity four orders of magnitude beyond current limits. The experiment will
have a single event sensitivity of about $2.5\times10^{-17}$ while limiting the
total background to less than 0.5 events. One potential background is due to
cosmic-ray muons producing an electron that is indistinguishable from signal
within the Mu2e apparatus. The cosmic-ray-veto system of the Mu2e experiment is
tasked with vetoing cosmic-ray-induced backgrounds with high efficiency without
inducing significant dead time and while operating in a high-intensity
environment. In this note the challenges related to the high-radiation
environment that influence the design of the cosmic-ray-veto system will be
discussed.


title:
On Lattices of Regular Sets of Natural Integers Closed under
  Decrementation

abstract:
  We consider lattices of regular sets of non negative integers, i.e. of sets
definable in Presbuger arithmetic. We prove that if such a lattice is closed
under decrement then it is also closed under many other functions: quotients by
an integer, roots, etc.


title:
Mixing Bandt-Pompe and Lempel-Ziv approaches: another way to analyze the
  complexity of continuous-states sequences

abstract:
  In this paper, we propose to mix the approach underlying Bandt-Pompe
permutation entropy with Lempel-Ziv complexity, to design what we call
Lempel-Ziv permutation complexity. The principle consists of two steps: (i)
transformation of a continuous-state series that is intrinsically multivariate
or arises from embedding into a sequence of permutation vectors, where the
components are the positions of the components of the initial vector when
re-arranged; (ii) performing the Lempel-Ziv complexity for this series of
`symbols', as part of a discrete finite-size alphabet. On the one hand, the
permutation entropy of Bandt-Pompe aims at the study of the entropy of such a
sequence; i.e., the entropy of patterns in a sequence (e.g., local increases or
decreases). On the other hand, the Lempel-Ziv complexity of a discrete-state
sequence aims at the study of the temporal organization of the symbols (i.e.,
the rate of compressibility of the sequence). Thus, the Lempel-Ziv permutation
complexity aims to take advantage of both of these methods. The potential from
such a combined approach - of a permutation procedure and a complexity analysis
- is evaluated through the illustration of some simulated data and some real
data. In both cases, we compare the individual approaches and the combined
approach.


title: Origin of Complexity and Conditional Predictability in Cellular Automata

abstract:
  A simple mechanism for the emergence of complexity in cellular automata out
of predictable dynamics is described. This leads to unfold the concept of
conditional predictability for systems whose trajectory can only be piecewise
known. The mechanism is used to construct a cellular automaton model for
discrete chimera-like states, where synchrony and incoherence in an ensemble of
identical oscillators coexist. The incoherent region is shown to have a
periodicity that is three orders of magnitude longer than the period of the
synchronous oscillation.

categories: nlin.CG cond-mat.stat-mech math-ph math.MP


title: Hadronic-origin TeV flare of M87 in April 2010

abstract:
  M87 is a giant radio galaxy with FR-I morphology. It underwent three episodes
of TeV flaring in recent years with the strongest one in April 2010 which was
jointly monitored by MAGIC, VERITAS and H.E.S.S. We explain its spectral energy
distribution in the energy range 0.3 TeV to 5 TeV by assuming that the flaring
occurs in the innermost region of the jet. In this region the low energy SSC
photons serve as the target for the Fermi-accelerated high energy protons of
energy < 30 TeV to form a delta resonance. The TeV photons are produced from
the subsequent decay of the delta resonance to neutral pions. In this scenario
the observed TeV flux of the 2010 flare is fitted very well.


title: Newtonian Dynamics from the principle of Maximum Caliber

abstract:
  The foundations of Statistical Mechanics can be recovered almost in their
entirety from the Principle of Maximum Entropy. In this work we show that its
non-equilibrium generalization, the Principle of Maximum Caliber (Jaynes,
1980), when applied to the unknown trajectory followed by a particle, leads to
Newton's second law under two quite intuitive assumptions (the expected square
displacement in one step and the spatial probability distribution of the
particle are known at all times). Our derivation explicitly highlights the role
of mass as an emergent measure of the fluctuations in velocity (inertia) and
the origin of potential energy as a manifestation of spatial correlations.
According to our findings, the application of Newton's equations is not limited
to mechanical systems, and therefore could be used in modelling ecological,
financial and biological systems, among others.


title: Some examples of division symbol algebras of degree 3 and 5

abstract:
  In this paper we provide an algorithm to compute the product between two
elements in a symbol algebra of degree n and we find an octonion non-division
algebra in a symbol algebra of degree three. Starting from this last idea, we
try to find an answer to the question if there are division symbol algebras of
degree three. The answer is positive and we provide, using MAGMA software, some
examples of division symbol algebras of degree 3 and of degree 5. Moreover, we
will give some interesting applications of the symbol algebras in number
theory.


title:
Concurrent learning-based online approximate feedback-Nash equilibrium
  solution of N-player nonzero-sum differential games

abstract:
  This paper presents a concurrent learning-based actor-critic-identifier
architecture to obtain an approximate feedback-Nash equilibrium solution to an
infinite horizon N-player nonzero-sum differential game online, without
requiring persistence of excitation (PE), for a nonlinear control-affine
system. Under a condition milder than PE, uniformly ultimately bounded
convergence of the developed control policies to the feedback-Nash equilibrium
policies is established.


title: Constraints on CP-violating Higgs couplings to the third generation

abstract:
  Discovering CP-violating effects in the Higgs sector would constitute an
indisputable sign of physics beyond the Standard Model. We derive constraints
on the CP-violating Higgs-boson couplings to top and bottom quarks as well as
to tau leptons from low-energy bounds on electric dipole moments, resumming
large logarithms when necessary. The present and future projections of the
sensitivities and comparisons with the LHC constraints are provided.
Non-trivial constraints are possible in the future, even if the Higgs boson
only couples to the third-generation fermions.


title: Approximations to $m$-coloured complete infinite hypergraphs

abstract:
  Given an edge colouring of a graph with a set of $m$ colours, we say that the
graph is (exactly) $m$-coloured if each of the colours is used. In 1999, Stacey
and Weidl, partially resolving a conjecture of Erickson from 1994, showed that
for a fixed natural number $m>2$ and for all sufficiently large $k$, there is a
$k$-colouring of the complete graph on $\mathbb{N}$ such that no complete
infinite subgraph is exactly $m$-coloured. In the light of this result, we
consider the question of how close we can come to finding an exactly
$m$-coloured complete infinite subgraph. We show that for a natural number $m$
and any finite colouring of the edges of the complete graph on $\mathbb{N}$
with $m$ or more colours, there is an exactly ${\hat m}$-coloured complete
infinite subgraph for some ${\hat m}$ satisfying $|m-{\hat m}|\le \sqrt{m/2} +
1/2$; this is best-possible up to the additive constant. We also obtain
analogous results for this problem in the setting of $r$-uniform hypergraphs.
Along the way, we also prove a recent conjecture of the second author and
investigate generalisations of this conjecture to $r$-uniform hypergraphs.


title: Percolation on interacting networks with feedback-dependency links

abstract:
  When real networks are considered, coupled networks with connectivity and
feedback-dependency links are not rare but more general. Here we develop a
mathematical framework and study numerically and analytically percolation of
interacting networks with feedback-dependency links. We find that when nodes of
between networks are lowly connected, the system undergoes from second order
transition through hybrid order transition to first order transition as
coupling strength increases. And, as average degree of each inter-network
increases, first order region becomes smaller and second-order region becomes
larger but hybrid order region almost keep constant. Especially, the results
implies that average degree \bar{k} between intra-networks has a little
influence on robustness of system for weak coupling strength, but for strong
coupling strength corresponding to first order transition system become robust
as \bar{k} increases. However, when average degree k of inter-network is
increased, the system become robust for all coupling strength. Additionally,
when nodes of between networks are highly connected, the hybrid order region
disappears and the system first order region becomes larger and secondorder
region becomes smaller. Moreover, we find that the existence of feedback
dependency links between interconnecting networks makes the system extremely
vulnerable by comparing non-feedback condition for the same parameters.


title:
Single particle potentials of asymmetric nuclear matter in different
  spin-isospin channels

abstract:
  We investigate the neutron and proton single particle (s.p.) potentials of
asymmetric nuclear matter and their isospin dependence in various spin-isospin
$ST$ channels within the framework of the Brueckner-Hartree-Fock approach. It
is shown that in symmetric nuclear matter, the s.p. potentials in both the
isospin-singlet T=0 channel and isospin-triplet T=1 channel are essentially
attractive, and the magnitudes in the two different channels are roughly the
same. In neutron-rich nuclear matter, the isospin-splitting of the proton and
neutron s.p. potentials turns out to be mainly determined by the
isospin-singlet T=0 channel contribution which becomes more attractive for
proton and more repulsive for neutron at higher asymmetries.


title:
Dynamics of blueshifted floating pulses in gas filled hollow-core
  photonic crystal fibers

abstract:
  Frequency blueshifting was recently observed in light pulses propagating on
gas filled hollow-core photonic crystal fibers where a plasma has been produced
due to photoionization of the gas. One of the propagation models that is
adequate to describe the actual experimental observations is here investigated.
It is a nonlinear Schr\"odinger equation with an extra term, to which we
applied a self-similar change of variables and found its accelerating solitons.
As in other NLS related models possessing accelerating solitons, there exist
asymmetrical pulses that decay as they propagate in some parameter region that
was here well defined.


title: A Scratch-like visual programming system for Microsoft Windows Phone 8

abstract:
  Pocket Code is a free and open source mobile visual programming system for
the Catrobat language. It allows users, starting from the age of eight, to
develop games and animations with their smartphones. Children can create
programs with their Android phone, iPhone, Windows Phone, or other smartphone
with an HTML5 browser. No notebook or desktop computer is needed. Pocket Code
is inspired by, but distinct from, the Scratch programming system developed by
the Lifelong Kindergarten Group at the MIT Media Lab. This tool demo describes
an in-practice experience with Pocket Code, the Windows Phone IDE for the
Catrobat language.


title: The planets around NN Ser: still there

abstract:
  We present 25 new eclipse times of the white dwarf binary NN Ser taken with
the high-speed camera ULTRACAM on the WHT and NTT, the RISE camera on the
Liverpool Telescope, and HAWK-I on the VLT to test the two-planet model
proposed to explain variations in its eclipse times measured over the last 25
years. The planetary model survives the test with flying colours, correctly
predicting a progressive lag in eclipse times of 36 seconds that has set in
since 2010 compared to the previous 8 years of precise times. Allowing both
orbits to be eccentric, we find orbital periods of 7.9 +/- 0.5 yr and 15.3 +/-
0.3 yr, and masses of 2.3 +/- 0.5 Mjup and 7.3 +/- 0.3 Mjup. We also find
dynamically long-lived orbits consistent with the data, associated with 2:1 and
5:2 period ratios. The data scatter by 0.07 seconds relative to the best-fit
model, by some margin the most precise of any of the proposed eclipsing compact
object planet hosts. Despite the high precision, degeneracy in the orbit fits
prevents a significant measurement of a period change of the binary and of
N-body effects. Finally, we point out a major flaw with a previous dynamical
stability analysis of NN Ser, and by extension, with a number of analyses of
similar systems.


title: Chandra Imaging of Gamma-Ray Binaries

abstract:
  We review the multiwavelength properties of the few known gamma-ray binaries,
focusing on extended emission recently resolved with Chandra. We discuss the
implications of these findings for the nature of compact objects and for
physical processes operating in these systems.


title:
Testing large-scale vortex formation against viscous layers in
  three-dimensional discs

abstract:
  Vortex formation through the Rossby wave instability (RWI) in protoplanetary
discs has been invoked to play a role in planet formation theory, and suggested
to explain the observation of large dust asymmetries in several transitional
discs. However, whether or not vortex formation operates in layered accretion
discs, i.e. models of protoplanetary discs including dead zones near the disc
midplane --- regions that are magnetically inactive and the effective viscosity
greatly reduced --- has not been verified. As a first step toward testing the
robustness of vortex formation in layered discs, we present non-linear
hydrodynamical simulations of global 3D protoplanetary discs with an imposed
kinematic viscosity that increases away from the disc midplane. Two sets of
numerical experiments are performed: (i) non-axisymmetric instability of
artificial radial density bumps in viscous discs; (ii) vortex-formation at
planetary gap edges in layered discs. Experiment (i) shows that the linear
instability is largely unaffected by viscosity and remains dynamical. The
disc-planet simulations also show the initial development of vortices at gap
edges, but in layered discs the vortices are transient structures which
disappear well into the non-linear regime. We suggest that the long term
survival of columnar vortices, such as those formed via the RWI, requires low
effective viscosity throughout the vertical extent of the disc, so such
vortices do not persist in layered discs.


title: APFEL: A PDF Evolution Library with QED corrections

abstract:
  Quantum electrodynamics and electroweak corrections are important ingredients
for many theoretical predictions at the LHC. This paper documents APFEL, a new
PDF evolution package that allows for the first time to perform DGLAP evolution
up to NNLO in QCD and to LO in QED, in the variable-flavor-number scheme and
with either pole or MSbar heavy quark masses. APFEL consistently accounts for
the QED corrections to the evolution of quark and gluon PDFs and for the
contribution from the photon PDF in the proton. The coupled QCD+QED equations
are solved in x-space by means of higher order interpolation, followed by
Runge-Kutta solution of the resulting discretized evolution equations. APFEL is
based on an innovative and flexible methodology for the sequential solution of
the QCD and QED evolution equations and their combination. In addition to PDF
evolution, APFEL provides a module that computes Deep-Inelastic Scattering
structure functions in the FONLL general-mass variable-flavor-number scheme up
to O($\alpha_s^2$). All the functionalities of APFEL can be accessed via a
Graphical User Interface, supplemented with a variety of plotting tools for
PDFs, parton luminosities and structure functions. Written in Fortran 77, APFEL
can also be used via the C/C++ and Python interfaces, and is publicly available
from the HepForge repository.


title:
The Great Escape III: Placing post-main-sequence evolution of planetary
  and binary systems in a Galactic context

abstract:
  Our improving understanding of the life cycle of planetary systems prompts
investigations of the role of the Galactic environment before, during and after
Asymptotic Giant Branch (AGB) stellar evolution. Here, we investigate the
interplay between stellar mass loss, Galactic tidal perturbations, and stellar
flybys for evolving stars which host one planet, smaller body or stellar binary
companion and reside in the Milky Way's bulge or disc. We find that the
potential evolutionary pathways from a main sequence (MS) to a white dwarf (WD)
planetary system are a strong function of Galactocentric distance only with
respect to the prevalence of stellar flybys. Planetary ejection and collision
with the parent star should be more common towards the bulge. At a given
location anywhere in the Galaxy, if the mass loss is adiabatic, then the
secondary is likely to avoid close flybys during AGB evolution, and cannot
eventually escape the resulting WD because of Galactic tides alone. Partly
because AGB mass loss will shrink a planetary system's Hill ellipsoid axes by
about 20 to 40 per cent, Oort clouds orbiting WDs are likely to be more
depleted and dynamically excited than on the MS.


title: Characterizing Diffused Stellar Light in simulated galaxy clusters

abstract:
  [Abridged] In this paper, we carry out a detailed analysis of the performance
of two different methods to identify the diffuse stellar light in cosmological
hydrodynamical simulations of galaxy clusters. One method is based on a
dynamical analysis of the stellar component. The second method is closer to
techniques commonly employed in observational studies. Both the dynamical
method and the method based on the surface brightness limit criterion are
applied to the same set of hydrodynamical simulations for a large sample about
80 galaxy clusters.
  We find significant differences between the ICL and DSC fractions computed
with the two corresponding methods, which amounts to about a factor of two for
the AGN simulations, and a factor of four for the CSF set. We also find that
the inclusion of AGN feedback boosts the DSC and ICL fractions by a factor of
1.5-2, respectively, while leaving the BCG+ICL and BCG+DSC mass fraction almost
unchanged. The sum of the BCG and DSC mass stellar mass fraction is found to
decrease from ~80 per cent in galaxy groups to ~60 per cent in rich clusters,
thus in excess of what found from observational analysis.
  We identify the average surface brightness limits that yields the ICL
fraction from the SBL method close to the DSC fraction from the dynamical
method. These surface brightness limits turn out to be brighter in the CSF than
in the AGN simulations. This is consistent with the finding that AGN feedback
makes BCGs to be less massive and with shallower density profiles than in the
CSF simulations. The BCG stellar component, as identified by both methods, are
slightly older and more metal-rich than the stars in the diffuse component.


title:
The role of interference in unraveling the ZZ-couplings of the newly
  discovered boson at the LHC

abstract:
  We present a general procedure for measuring the tensor structure of the
coupling of the scalar Higgs-like boson recently discovered at the LHC to two Z
bosons, including the effects of interference among different operators. To
motivate our concern with this interference, we explore the parameter space of
the couplings in the effective theory describing these interactions and
illustrate the effects of interference on the differential dilepton mass
distributions. Kinematic discriminants for performing coupling measurements
that utilize the effects of interference are developed and described. We
present projections for the sensitivity of coupling measurements that use these
discriminants in future LHC operation in a variety of physics scenarios.


title:
Reversal or no reversal: the evolution of the star formation
  rate-density relation up to z~1.6

abstract:
  We investigate the evolution of the star formation rate (SFR)-density
relation in the Extended Chandra Deep Field South (ECDFS) and the Great
Observatories Origin Deep Survey (GOODS) fields up to z~1.6. In addition to the
"traditional method", in which the environment is defined according to a
statistical measurement of the local galaxy density, we use a "dynamical"
approach, where galaxies are classified according to three different
environment regimes: group, "filament-like", and field. Both methods show no
evidence of a SFR-density reversal. Moreover, group galaxies show a mean SFR
lower than other environments up to z~1, while at earlier epochs group and
field galaxies exhibit consistent levels of star formation (SF) activity. We
find that processes related to a massive dark matter halo must be dominant in
the suppression of the SF below z~1, with respect to purely density-related
processes. We confirm this finding by studying the distribution of galaxies in
different environments with respect to the so-called Main Sequence (MS) of
star-forming galaxies. Galaxies in both group and "filament-like" environments
preferentially lie below the MS up to z~1, with group galaxies exhibiting lower
levels of star-forming activity at a given mass. At z>1, the star-forming
galaxies in groups reside on the MS. Groups exhibit the highest fraction of
quiescent galaxies up to z~1, after which group, "filament-like", and field
environments have a similar mix of galaxy types. We conclude that groups are
the most efficient locus for star-formation quenching. Thus, a fundamental
difference exists between bound and unbound objects, or between dark matter
haloes of different masses.


title:
The XMM-Newton spectrum of a candidate recoiling supermassive black
  hole: an elusive inverted P-Cygni profile

abstract:
  We present a detailed spectral analysis of new XMM-Newton data of the source
CXOC J100043.1+020637, also known as CID-42, detected in the COSMOS survey at z
= 0.359. Previous works suggested that CID-42 is a candidate recoiling
supermassive black holes showing also an inverted P-Cygni profile in the X- ray
spectra at ~6 keV (rest) with an iron emission line plus a redshifted
absorption line (detected at 3sigma in previous XMM-Newton and Chandra
observations). Detailed analysis of the absorption line suggested the presence
of ionized material inflowing into the black hole at high velocity. In the new
long XMM-Newton observation, while the overall spectral shape remains constant,
the continuum 2-10 keV flux decreased of ~20% with respect to previous
observation and the absorption line is undetected. The upper limit on the
intensity of the absorption line is EW<162 keV. Extensive Monte Carlo
simulations show that the non detection of the line is solely due to variation
in the properties of the inflowing material, in agreement with the transient
nature of these features, and that the intensity of the line is lower than the
previously measured with a probability of 98.8%. In the scenario of CID-42 as
recoiling SMBH, the absorption line can be interpreted as due to inflow of gas
with variable density and located in the proximity of the SMBH and recoiling
with it. New monitoring observations will be requested to further characterize
this line.


title: Optical simulation of Majorana physics

abstract:
  We show a procedure to classically simulate the Majorana equation in 1+1
dimensions via two one-dimensional photonic crystals. We use a decomposition of
the Majorana equation into two Dirac equations and propose a novel approach
that uses a bi-chromatic refractive index distribution and nearest neighbor
couplings of the type found in Glauber-Fock lattices. This allows us to escape
the restriction of staying near the Brillouin zone imposed by the classical
simulation of Dirac dynamics with bi-chromatic lattices. Furthermore, it is
possible to simulate the evolution of Gaussian wavepackets under the
Majorana/Dirac equation with light impinging only into the first waveguide of
our bi-chromatic-Glauber-Fock lattice.


title: Measuring nonlocal Lagrangian peak bias

abstract:
  We investigate nonlocal Lagrangian bias contributions involving gradients of
the linear density field, for which we have predictions from the excursion set
peak formalism. We begin by writing down a bias expansion which includes all
the bias terms, including the nonlocal ones. Having checked that the model
furnishes a reasonable fit to the halo mass function, we develop a 1-point
cross-correlation technique to measure bias factors associated with
2-distributed quantities. We validate the method with numerical realizations of
peaks of Gaussian random fields before we apply it to N-body simulations. We
focus on the lowest (quadratic) order nonlocal contributions. We can reproduce
our measurement of \chi_{10} if we allow for an offset between the Lagrangian
halo center-of-mass and the peak position. The sign and magnitude of \chi_{10}
is consistent with Lagrangian haloes sitting near linear density maxima. The
resulting contribution to the halo bias can safely be ignored for M = 10^13
Msun/h, but could become relevant at larger halo masses. For the second
nonlocal bias \chi_{01} however, we measure a much larger magnitude than
predicted by our model. We speculate that some of this discrepancy might
originate from nonlocal Lagrangian contributions induced by nonspherical
collapse.


title: A nova re-accretion model for J-type carbon stars

abstract:
  The J-type carbon (J)-stars constitute 10-15% of the observed carbon stars in
both our Galaxy and the Large Magellanic Cloud (LMC). They are characterized by
strong 13C absorption bands with low 12C/13C ratios along with other chemical
signatures peculiar for typical carbon stars, e.g. a lack of s-process
enhancement. Most of the J-stars are dimmer than the N-type carbon stars some
of which, by hot-bottom burning, make 13C only in a narrow range of masses. We
investigate a binary-star formation channel for J-stars involving re-accretion
of carbon-rich nova ejecta on main-sequence companions to low-mass
carbon-oxygen white-dwarfs. The subsequent evolution of the companion stars in
such systems is studied with a rapid binary evolutionary code to predict
chemical signatures of nova pollution in systems which merge into giant single
stars. A detailed population synthesis study is performed to estimate the
number of these mergers and compare their properties with observed J-stars. Our
results predict that such nova polluted mergers evolve with low luminosities as
well as low 12C/13C ratios like the majority of observed J-stars (e.g. in the
LMC) but cannot account for the observed fraction of J-stars in existing
surveys of carbon stars.


title:
Sequence-Structure Relationship in Proteins: a Computational Analysis of
  Proteins that Differ in Sequence but Share the Same Fold

abstract:
  Mapping between sequence and structure is currently an open problem in
structural biology. Despite many experimental and computational efforts it is
not clear yet how the structure is encoded in the sequence. Answering this
question may pave the way for predicting a protein fold given its sequence.
  My doctoral studies have focused on a particular phenomenon relevant to the
protein sequence-structure relationship. It has been observed that many
proteins having apparently dissimilar sequences share the same native fold. The
phenomenon of mapping many divergent sequences into a single fold raises the
question of which positions along the sequence are important for the
conservation of fold and function in dissimilar sequences. Detecting those
positions, and classifying them according to role can help understand which
elements in a sequence are important for maintenance of structure and/or
function. In the course of my doctoral research I have attempted to discover
and characterize those positions.


title: Sequential Monte Carlo Bandits

abstract:
  In this paper we propose a flexible and efficient framework for handling
multi-armed bandits, combining sequential Monte Carlo algorithms with
hierarchical Bayesian modeling techniques. The framework naturally encompasses
restless bandits, contextual bandits, and other bandit variants under a single
inferential model. Despite the model's generality, we propose efficient Monte
Carlo algorithms to make inference scalable, based on recent developments in
sequential Monte Carlo methods. Through two simulation studies, the framework
is shown to outperform other empirical methods, while also naturally scaling to
more complex problems for which existing approaches can not cope. Additionally,
we successfully apply our framework to online video-based advertising
recommendation, and show its increased efficacy as compared to current state of
the art bandit algorithms.


title:
Astrometric Detection of Giant Planets Around Nearby M Dwarfs: The Gaia
  Potential

abstract:
  [abridged] We carry out numerical simulations to gauge the Gaia potential for
precision astrometry of exoplanets orbiting a sample of known dM stars within
30 pc from the Sun. (1) It will be possible to accurately determine orbits and
masses for Jupiter-mass planets with orbital periods in the range 0.2<P<6.0 yr
and with an astrometric signal-to-noise ratio > 10. Given present-day estimates
of the planet fraction f_p around M dwarfs, 100 giant planets could be found by
Gaia around the sample. Comprehensive screening by Gaia of the reservoir of
4x10^5 M dwarfs within 100 pc could result in 2600 detections and as many as
500 accurate orbit determinations. The value of f_p could then be determined
with an accuracy of 2%, an improvement by over an order of magnitude with
respect to the most precise values available to-date; (2) in the same period
range, inclination angles corresponding to quasi-edge-on configurations will be
determined with enough precision (a few percent) so that it will be possible to
identify intermediate-separation planets which are potentially transiting
within the errors. Gaia could alert us of the existence of 10 such systems.
More than 250 candidates could be identified assuming solutions compatible with
transit configurations within 10% accuracy, although a large fraction of these
(85%) could be false positives; (3) for well-sampled orbits, the uncertainties
on planetary ephemerides, separation and position angle, will degrade at
typical rates of < 1 mas/yr and < 2 deg/yr, respectively; (4) planetary phases
will be measured with typical uncertainties of several degrees, resulting
(under the assumption of purely scattering atmospheres) in phase-averaged
errors on the phase function of 0.05, and expected uncertainties in the
determination of the emergent flux of intermediate-separation (0.3<a<2.0 AU)
giant planets of 20%. [abridged]


title:
Well-conditioned boundary integral equation formulations for the
  solution of high-frequency electromagnetic scattering problems

abstract:
  We present several versions of Regularized Combined Field Integral Equation
(CFIER) formulations for the solution of three dimensional frequency domain
electromagnetic scattering problems with Perfectly Electric Conducting (PEC)
boundary conditions. Just as in the Combined Field Integral Equations (CFIE),
we seek the scattered fields in the form of a combined magnetic and electric
dipole layer potentials that involves a composition of the latter type of
boundary layers with regularizing operators. The regularizing operators are of
two types: (1) modified versions of electric field integral operators with
complex wavenumbers, and (2) principal symbols of those operators in the sense
of pseudodifferential operators. We show that the boundary integral operators
that enter these CFIER formulations are Fredholm of the second kind, and
invertible with bounded inverses in the classical trace spaces of
electromagnetic scattering problems. We present a spectral analysis of CFIER
operators with regularizing operators that have purely imaginary wavenumbers
for spherical geometries. Under certain assumptions on the coupling constants
and the absolute values of the imaginary wavenumbers of the regularizing
operators, we show that the ensuing CFIER operators are coercive for spherical
geometries. These properties allow us to derive wavenumber explicit bounds on
the condition numbers of certain CFIER operators that have been proposed in the
literature. When regularizing operators with complex wavenumbers with non-zero
real parts are used, we show numerical evidence that those complex wavenumbers
can be selected in a manner that leads to CFIER formulations whose condition
numbers can be bounded independently of frequency for spherical geometries.


title: Charged lepton mixing processes in 331 Models

abstract:
  Processes $\tau\rightarrow l\gamma$, $\tau\rightarrow lll$ with $l= e,\mu$
and $\mu(\tau) \to e (\mu) \gamma$ are evaluated in the framework of a model
based on the extended symmetry gauge $SU(3)_c \otimes SU(3)_L \otimes U(1)_Y$
with a leptonic sector consistent of five triplets. Lepton flavor violating
processes are allowed at tree level in this model through the new $Z'$ gauge
boson. We obtained bounds for the mixing angles in the leptonic sector of the
model, considering the experimental measurements of the processes from the
BELLE and the BABAR collaborations.


title:
Room temperature optical manipulation of nuclear spin polarization in
  GaAsN

abstract:
  The effect of hyperfine interaction on the room-temperature defect-enabled
spin filtering effect in GaNAs alloys is investigated both experimentally and
theoretically through a master equation approach based on the hyperfine and
Zeeman interaction between electron and nuclear spin of the spin filtering
defect. We show that the nuclear spin polarization can be tuned through the
optically induced spin polarization of conduction band electrons.


title:
The probe technique far-from-equilibrium: Magnetic field symmetries of
  nonlinear transport

abstract:
  The probe technique is a simple mean to incorporate elastic and inelastic
processes into quantum dynamics. Using numerical simulations, we demonstrate
that this tool can be employed beyond the analytically tractable linear
response regime, providing a stable solution for the probe parameters:
temperature and chemical potential. Adopting four probes: dephasing, voltage,
temperature, and voltage-temperature, mimicking different elastic and inelastic
effects, we focus on magnetic field and gate voltage symmetries of charge
current and heat current in Aharonov-Bohm interferometers, potentially
far-from-equilibrium. Considering electron current, we prove analytically that
in the linear response regime inelastic scattering processes do not break the
Onsager symmetry. Beyond linear response, even (odd) conductance terms obey an
odd (even) symmetry with the threading magnetic flux, as long as the system
acquires a spatial inversion symmetry. When spatial asymmetry is introduced
particle-hole symmetry assures that nonlinear conductance terms maintain
certain symmetries with respect to magnetic field and gate voltage. These
analytic results are supported by numerical simulations. Analogous results are
obtained for the electron heat current. We also demonstrate that a double-dot
Aharonov-Bohm interferometer acts as a rectifier when two conditions are met:
(i) many-body effects are included, here in the form of inelastic scattering,
and (ii) time reversal symmetry is broken.


title:
On the connection between quantum nonlocality and phase sensitivity of
  two-mode entangled Fock state superpositions

abstract:
  In two-mode interferometry, for a given total photon number $N$, entangled
Fock state superpositions of the form $(|N-m\rangle_a|m\rangle_b+e^{i
(N-2m)\phi}|m\rangle_a|N-m\rangle_b)/\sqrt{2}$ have been considered for phase
estimation. Indeed all such states are maximally mode-entangled and violate a
Clauser-Horne-Shimony-Holt (CHSH) inequality. However, they differ in their
optimal phase estimation capabilities as given by their quantum Fisher
informations. The quantum Fisher information is the largest for the $N00N$
state $(|N\rangle_a|0\rangle_b+e^{i N\phi}|0\rangle_a|N\rangle_b)/\sqrt{2}$ and
decreases for the other states with decreasing photon number difference between
the two modes. We ask the question whether for any particular Clauser-Horne
(CH) (or CHSH) inequality, the maximal values of the CH (or the CHSH)
functional for the states of the above type follow the same trend as their
quantum Fisher informations, while also violating the classical bound whenever
the states are capable of sub-shot-noise phase estimation, so that the
violation can be used to quantify sub-shot-noise sensitivity. We explore CH and
CHSH inequalities in a homodyne setup. Our results show that the amount of
violation in those nonlocality tests may not be used to quantify sub-shot-noise
sensitivity of the above states.


title:
Moth-inspired navigation algorithm in a turbulent odor plume from a
  pulsating source

abstract:
  Some female moths attract male moths by emitting series of pulses of
pheromone filaments propagating downwind. The turbulent nature of the wind
creates a complex flow environment, and causes the filaments to propagate in
the form of patches with varying concentration distributions. Inspired by moth
navigation capabilities, we propose a navigation strategy that enables a flier
to locate a pulsating odor source in a windy environment using a single
threshold-based detection sensor. The strategy is constructed based on the
physical properties of the turbulent flow carrying discrete puffs of odor and
does not involve learning, memory, complex decision making or statistical
methods. We suggest that in turbulent plumes from a pulsating point source, an
instantaneously measurable quantity referred as a "puff crossing time",
improves the success rate as compared to the navigation strategy based on
"internal counter" that does not use this information. Using computer
simulations of fliers navigating in turbulent plumes of the pulsating point
source for varying flow parameters: turbulent intensities, plume meandering and
wind gusts, we obtained trajectories qualitatively resembling male moths
flights towards the pheromone sources. We quantified the probability of a
successful navigation as well as the flight parameters such as the time spent
searching and the total flight time, with respect to different turbulent
intensities, meandering or gusts. The concepts learned using this model may
help to design odor-based navigation of miniature airborne autonomous vehicles.


title: "Exotic" black holes with torsion

abstract:
  In the context of three-dimensional gravity with torsion, the concepts of
standard and "exotic" Banados-Teitelboim-Zanelli black holes are generalized by
going over to black holes with torsion. This approach provides a unified
insight into thermodynamics of black holes, with or without torsion.


title: Measurement of thin films using very long acoustic wavelengths

abstract:
  A procedure for measuring material thickness by means of necessarily-long
acoustic wavelengths is examined. The approach utilizes a temporal phase lag
caused by the impulse time of wave momentum transferred through a thin layer
that is much denser than its surrounding medium. In air, it is predicted that
solid or liquid layers below approximately 1/2000 of the acoustic wavelength
will exhibit a phase shift with an arctangent functional dependence on
thickness and layer density. The effect is verified for thin films on the scale
of 10 microns using audible frequency sound (7 kHz). Soap films as thin as 100
nm are then measured using 40 kHz air ultrasound. The method's potential for
imaging applications is demonstrated by combining the approach with near-field
holography, resulting in reconstructions with sub-wavelength resolution in both
the depth and lateral directions. Potential implications at very high and very
low acoustic frequencies are discussed.


title: Universal quantum oscillations in the underdoped cuprate superconductors

abstract:
  The metallic state of the underdoped high-Tc cuprates has remained an enigma:
How may seemingly disconnected Fermi surface segments, observed in zero
magnetic field as a result of the opening of a partial gap (the pseudogap),
possess conventional quasiparticle properties? How do the small Fermi-surface
pockets evidenced by the observation of quantum oscillations (QO) emerge as
superconductivity is suppressed in high magnetic fields? Such QO, discovered in
underdoped YBa2Cu3O6.5 (Y123) and YBa2Cu4O8 (Y124), signify the existence of a
conventional Fermi surface (FS). However, due to the complexity of the crystal
structures of Y123 and Y124 (CuO2 double-layers, CuO chains, low structural
symmetry), it has remained unclear if the QO are specific to this particular
family of cuprates. Numerous theoretical proposals have been put forward to
explain the route toward QO, including materials-specific scenarios involving
CuO chains and scenarios involving the quintessential CuO2 planes. Here we
report the observation of QO in underdoped HgBa2CuO4+{\delta} (Hg1201), a model
cuprate superconductor with individual CuO2 layers, high tetragonal symmetry,
and no CuO chains. This observation proves that QO are a universal property of
the underdoped CuO2 planes, and it opens the door to quantitative future
studies of the metallic state and of the Fermi-surface reconstruction
phenomenon in this structurally simplest cuprate.


title: Narrowing the Gap: Random Forests In Theory and In Practice

abstract:
  Despite widespread interest and practical use, the theoretical properties of
random forests are still not well understood. In this paper we contribute to
this understanding in two ways. We present a new theoretically tractable
variant of random regression forests and prove that our algorithm is
consistent. We also provide an empirical evaluation, comparing our algorithm
and other theoretically tractable random forest models to the random forest
algorithm used in practice. Our experiments provide insight into the relative
importance of different simplifications that theoreticians have made to obtain
tractable models for analysis.


title:
Integral equations requiring small numbers of Krylov-subspace iterations
  for two-dimensional penetrable scattering problems

abstract:
  This paper presents a class of boundary integral equations for the solution
of problems of electromagnetic and acoustic scattering by two dimensional
homogeneous penetrable scatterers with smooth boundaries. The new integral
equations, which, as is established in this paper, are uniquely solvable
Fredholm equations of the second kind, result from representations of fields as
combinations of single and double layer potentials acting on appropriately
chosen regularizing operators. As demonstrated in this text by means of a
variety of numerical examples (that resulted from a high-order Nystrom
computational implementation of the new equations), these "regularized combined
equations" can give rise to important reductions in computational costs, for a
given accuracy, over those resulting from previous boundary integral
formulations for transmission problems.


title: Tight orientably-regular polytopes

abstract:
  Every equivelar abstract polytope of type $\{p_1, \ldots, p_{n-1}\}$ has at
least $2p_1 \cdots p_{n-1}$ flags. Polytopes that attain this lower bound are
called tight. Here we investigate the question of under what conditions there
is a tight orientably-regular polytope of type $\{p_1, \ldots, p_{n-1}\}$. We
show that it is necessary and sufficient that whenever $p_i$ is odd, both
$p_{i-1}$ and $p_{i+1}$ are even divisors of $2p_i$.


title: Adiabatic cooling of Majorana zero-modes in topological superconductors

abstract:
  We show that the presence of Majorana zero-modes in a one-dimensional
topological superconductor can be detected by adiabatic cooling. This cooling
effect results from an increase of the topological entropy associated with the
ground state degeneracy due to such modes. Here, we consider an experimentally
feasible topological superconductor: a strong spin-orbit coupled semiconducting
quantum wire interfaced with an s-wave superconductor and subjected to a
magnetic field. Numerical simulations of realistic experimental geometries
indicate that the creation of Majorana zero-modes, which can be achieved by
tuning of electronic gates or the external magnetic field, results in a
measurable cooling effect. We also argue that this cooling effect results in an
increase in the zero bias peak conductance.


title: On Association Cells in Random Heterogeneous Networks

abstract:
  Characterizing user to access point (AP) association strategies in
heterogeneous cellular networks (HetNets) is critical for their performance
analysis, as it directly influences the load across the network. In this
letter, we introduce and analyze a class of association strategies, which we
term stationary association, and the resulting association cells. For random
HetNets, where APs are distributed according to a stationary point process, the
area of the resulting association cells are shown to be the marks of the
corresponding point process. Addressing the need of quantifying the load
experienced by a typical user, a "Feller-paradox" like relationship is
established between the area of the association cell containing origin and that
of a typical association cell. For the specific case of Poisson point process
and max power/SINR association, the mean association area of each tier is
derived and shown to increase with channel gain variance and decrease in the
path loss exponents of the corresponding tier.


title: Star formation efficiency and flattened gradients in M31

abstract:
  We present a chemical evolution model for M31 based on a pronounced
inside-out formation scenario. The model reproduces the three main
observational constraints of the M31 disk: the radial distributions of the
total baryonic mass, the gas mass, and the O/H abundance. The model shows good
agreement with the observed: SFR(r), Mstars(r), the C/H, N/H, Mg/H, Si/H, S/H,
Ar/H, Cr/H, Fe/H, and Z gradients. From reproducing the observed gas mass, we
find that the star formation efficiency is variable in space, for the whole
disk, and is constant in time for most of the evolution (t< 12.8 Gyr). From
reproducing the observed SFR, we find that the efficiency decreases almost to
zero for 12.8<t(Gyr)< 13.0 and r>12 kpc. All the predicted Xi/H(r) gradients
show three different slopes, due to the r-dependence of the the star formation
efficiency and the inside-out galactic formation.


title: Casimir Torque in Inhomogeneous Dielectric Plates

abstract:
  In this work, we consider a torque caused by the well known quantum
mechanical Casimir effect arising from quantized field fluctuations between
plates with inhomogeneous, sharply discontinuous, dielectric properties. While
the Casimir effect is a relatively well understood phenomenon, systems
resulting in lateral or rotational forces are far less developed; to our
knowledge, a theoretical study of discontinuous dielectric variants of such
systems has not been attempted. We utilize a Proximity Force Approximation in
conjunction with the Lifshitz dielectric formula to perform theoretical
analyses of resultant torques in systems with bisected and quadrisected
dielectric regions. We also develop a high precision Monte Carlo type numerical
integrator to approximate our derived expressions. Our calculations of an
energy density linear with the alignment angle result in a constant torque and
have implications in NEMS (nano electromechanical systems) and MEMS (micro
electromechanical systems), including a postulated nanoscale oscillating drive
mechanism powered by quantum field interactions.


title:
Degree-Scale CMB Polarization Measurements from Three Years of BICEP1
  Data

abstract:
  BICEP1 is a millimeter-wavelength telescope designed specifically to measure
the inflationary B-mode polarization of the Cosmic Microwave Background (CMB)
at degree angular scales. We present results from an analysis of the data
acquired during three seasons of observations at the South Pole (2006 to 2008).
This work extends the two-year result published in Chiang et al. (2010), with
additional data from the third season and relaxed detector-selection criteria.
This analysis also introduces a more comprehensive estimation of band-power
window functions, improved likelihood estimation methods and a new technique
for deprojecting monopole temperature-to-polarization leakage which reduces
this class of systematic uncertainty to a negligible level. We present maps of
temperature, E- and B-mode polarization, and their associated angular power
spectra. The improvement in the map noise level and polarization spectra error
bars are consistent with the 52% increase in integration time relative to
Chiang et al. (2010). We confirm both self-consistency of the polarization data
and consistency with the two-year results. We measure the angular power spectra
at 21 <= l <= 335 and find that the EE spectrum is consistent with Lambda Cold
Dark Matter (LCDM) cosmology, with the first acoustic peak of the EE spectrum
now detected at 15sigma. The BB spectrum remains consistent with zero. From
B-modes only, we constrain the tensor-to-scalar ratio to r = 0.03+0.27-0.23, or
r < 0.70 at 95% confidence level.


title: On lattice sums and Wigner limits

abstract:
  Wigner limits are given formally as the difference between a lattice sum,
associated to a positive definite quadratic form, and a corresponding multiple
integral. To define these limits, which arose in work of Wigner on the energy
of static electron lattices, in a mathematically rigorous way one commonly
truncates the lattice sum and the corresponding integral and takes the limit
along expanding hypercubes or other regular geometric shapes. We generalize the
known mathematically rigorous two and three dimensional results regarding
Wigner limits, as laid down in [Analysis of certain lattice sums, D. Borwein,
J. M. Borwein, and R. Shail, 1989], to integer lattices of arbitrary dimension.
In doing so, we also resolve a problem posed in Chapter 7 of [Lattice Sums:
Then and Now, J. M. Borwein, L. Glasser, R. McPhedran, J. G. Wan, and I. J.
Zucker, 2013].
  For the sake of clarity, we begin by considering the simpler case of cubic
lattice sums first, before treating the case of arbitrary quadratic forms. We
also consider limits taken along expanding hyperballs with respect to general
norms, and connect with classical topics such as Gauss's circle problem. An
appendix is included to recall certain properties of Epstein zeta functions
that are either used in the paper or serve to provide perspective.


title:
Soliton pair generation in the interactions of Airy and nonlinear
  accelerating beams

abstract:
  We investigate numerically the interactions of two in-phase and out-of-phase
Airy beams and nonlinear accelerating beams in Kerr and saturable nonlinear
media, in one transverse dimension. We find that bound and unbound soliton
pairs, as well as single solitons, can form in such interactions. If the
interval between two incident beams is large relative to the width of their
first lobes, the generated soliton pairs just propagate individually and do not
interact. However, if the interval is comparable to the widths of the maximum
lobes, the pairs interact and display varied behavior. In the in-phase case,
they attract each other and exhibit stable bound, oscillating, and unbound
states, after shedding some radiation initially. In the out-of-phase case, they
repel each other and after an initial interaction, fly away as individual
solitons. While the incident beams display acceleration, the solitons or
soliton pairs generated from those beams do not.


title:
A State of the Art of Word Sense Induction: A Way Towards Word Sense
  Disambiguation for Under-Resourced Languages

abstract:
  Word Sense Disambiguation (WSD), the process of automatically identifying the
meaning of a polysemous word in a sentence, is a fundamental task in Natural
Language Processing (NLP). Progress in this approach to WSD opens up many
promising developments in the field of NLP and its applications. Indeed,
improvement over current performance levels could allow us to take a first step
towards natural language understanding. Due to the lack of lexical resources it
is sometimes difficult to perform WSD for under-resourced languages. This paper
is an investigation on how to initiate research in WSD for under-resourced
languages by applying Word Sense Induction (WSI) and suggests some interesting
topics to focus on.


title:
Local Feature or Mel Frequency Cepstral Coefficients - Which One is
  Better for MLN-Based Bangla Speech Recognition?

abstract:
  This paper discusses the dominancy of local features (LFs), as input to the
multilayer neural network (MLN), extracted from a Bangla input speech over mel
frequency cepstral coefficients (MFCCs). Here, LF-based method comprises three
stages: (i) LF extraction from input speech, (ii) phoneme probabilities
extraction using MLN from LF and (iii) the hidden Markov model (HMM) based
classifier to obtain more accurate phoneme strings. In the experiments on
Bangla speech corpus prepared by us, it is observed that the LFbased automatic
speech recognition (ASR) system provides higher phoneme correct rate than the
MFCC-based system. Moreover, the proposed system requires fewer mixture
components in the HMMs.


title: Fixation for coarsening dynamics in 2D slabs

abstract:
  For the zero temperature limit of Ising Glauber Dynamics on 2D slabs the
existence or nonexistence of vertices that do not fixate is determined as a
function of slab thickness.