title:
Spread of visited sites of a random walk along the generations of a
  branching process

abstract:
  In this paper we consider a null recurrent random walk in random environment
on a super-critical Galton-Watson tree. We consider the case where the
log-Laplace transform $\psi$ of the branching process satisfies
$\psi(1)=\psi'(1)=0$ for which G. Faraud, Y. Hu and Z. Shi in \cite{HuShi10b}
show that, with probability one, the largest generation visited by the walk,
until the instant $n$, is of the order of $(\log n)^3$. In
\cite{AndreolettiDebs1} we prove that the largest generation entirely visited
behaves almost surely like $\log n$ up to a constant. Here we study how the
walk visits the generations $\ell=(\log n)^{1+ \zeta}$, with $0 < \zeta <2$. We
obtain results in probability giving the asymptotic logarithmic behavior of the
number of visited sites at a given generation. We prove that there is a phase
transition at generation $(\log n)^2$ for the mean of visited sites until $n$
returns to the root. Also we show that the visited sites spread all over the
tree until generation $\ell$.


title: Flatlandia : a flat spacetime description of gravitation

abstract:
  The proof that a consistent theory of gravity cannot be constructed in a flat
spacetime rests on the {\it assumption} that atoms be equal in every
conditions. However special relativity and the principle of equivalence impose
that atoms are equal only when relatively at rest and in equivalent
gravitational positions. This is further backed up by implementing in QM the
mass variation for moving objects and for bodies in a gravitational field.


title: Velocity of sound in the relic photon sea

abstract:
  We determine the velocity of sound in the blackbody gas of photons and in the
gas of relic photons. Derivation is based on the thermodynamic theory of the
photon gas and the Einstein relation between energy and mass. The spectral form
for the n-dimensional blackbody is derived. The 1D, 2D and 3D blackbody
radiation is specified. It is mentioned the possibility of creation of the Mach
cone in case that the high energy cosmical particles moves with the speed
greater than the velocity of sound in cosmical relic photon sea. Key words:
Sound, elasticity, thermodynamics, blackbody, relic photons, Mach's cone.


title:
An Effective Potential Theory for Transport Coefficients Across Coupling
  Regimes

abstract:
  A plasma transport theory that spans weak to strong coupling is developed
from a binary collision picture, but where the interaction potential is taken
to be an effective potential that includes correlation effects and screening
self-consistently. This physically motivated approach provides a practical
model for evaluating transport coefficients across coupling regimes. The theory
is shown to compare well with classical molecular dynamics simulations of
temperature relaxation in electron-ion plasmas, as well as simulations and
experiments of self-diffusion in one component plasmas. The approach is
versatile and can be applied to other transport coefficients as well.


title:
New Cosmological Model and Its Implications on Observational Data
  Interpretation

abstract:
  The paradigm of \Lambda CDM cosmology works impressively well and with the
concept of inflation it explains the universe after the time of decoupling.
However there are still a few concerns; after much effort there is no detection
of dark matter and there are significant problems in the theoretical
description of dark energy. We will consider a variant of the cosmological
spherical shell model, within FRW formalism and will compare it with the
standard \Lambda CDM model. We will show that our new topological model
satisfies cosmological principles and is consistent with all observable data,
but that it may require new interpretation for some data. Considered will be
constraints imposed on the model, as for instance the range for the size and
allowed thickness of the shell, by the supernovae luminosity distance and CMB
data. In this model propagation of the light is confined along the shell, which
has as a consequence that observed CMB originated from one point or a limited
space region. It allows to interpret the uniformity of the CMB without
inflation scenario. In addition this removes any constraints on the uniformity
of the universe at the early stage and opens a possibility that the universe
was not uniform and that creation of galaxies and large structures is due to
the inhomogeneities that originated in the Big Bang.


title: Satellite motion in a non-singular gravitational potential

abstract:
  We study the effects of a non singular gravitational potential on satellite
orbits by deriving the corresponding time rates of change of its orbital
elements. This is achieved by expanding the non singular potential into power
series up to second order. This series contains three terms, the first being
the Newtonian potential and the other two, (first order term)and (second order
term), express deviations of the singular potential from the Newtonian. These
deviations from the Newtonian potential are taken as disturbing potential terms
in the Lagrange planetary equations that provide the time rates of change of
the orbital elements of a satellite in a non singular gravitational field. We
split these effects into secular, low and high frequency components and we
evaluate them numerically using the low Earth orbiting mission Gravity Recovery
and Climate Experiment (GRACE). We show that the secular effect of the second
order disturbing term on the perigee and the mean anomaly are, 4.307 10^-9/a
and -2.533 10^-15/a respectively. These effects, are far too small and most
likely cannot easily be observed with todays technology. Numerical evaluation
of the low and high frequency effects of the disturbing term on low Earth
orbiters like GRACE are very small and undetectable by current observational
means.


title:
Terahertz quantum cascade lasers with thin resonant-phonon depopulation
  active regions and surface-plasmon waveguides

abstract:
  We report three-well, resonant-phonon depopulation terahertz quantum cascade
lasers with semi-insulating surface-plasmon waveguides and reduced active
region (AR) thicknesses. Devices with thicknesses of 10, 7.5, 6, and 5 {\mu}m
are compared in terms of threshold current density, maximum operating
temperature, output power and AR temperature. Thinner ARs are technologically
less demanding for epitaxial growth and result in reduced electrical heating of
devices. However, it is found that 7.5-{\mu}m-thick devices give the lowest
electrical power densities at threshold, as they represent the optimal
trade-off between low electrical resistance and low threshold gain.


title: Optimal stochastic transport in inhomogeneous thermal environments

abstract:
  We consider optimization of the average entropy production in inhomogeneous
temperature environments within the framework of stochastic thermodynamics. For
systems modeled by Langevin equations (e.g. a colloidal particle in a heat
bath) it has been recently shown that a space dependent temperature breaks the
time reversal symmetry of the fast velocity degrees of freedom resulting in an
anomalous contribution to the entropy production of the overdamped dynamics. We
show that optimization of entropy production is determined by an auxiliary
deterministic problem describing motion on a curved manifold in a potential.
The "anomalous contribution" to entropy plays the role of the potential and the
inverse of the diffusion tensor is the metric. We also find that entropy
production is not minimized by adiabatically slow, quasi-static protocols but
there is a finite optimal duration for the transport process. As an example we
discuss the case of a linearly space dependent diffusion coefficient.


title: Group-Sparse Model Selection: Hardness and Relaxations

abstract:
  Group-based sparsity models are proven instrumental in linear regression
problems for recovering signals from much fewer measurements than standard
compressive sensing. The main promise of these models is the recovery of
"interpretable" signals through the identification of their constituent groups.
In this paper, we establish a combinatorial framework for group-model selection
problems and highlight the underlying tractability issues. In particular, we
show that the group-model selection problem is equivalent to the well-known
NP-hard weighted maximum coverage problem (WMC). Leveraging a graph-based
understanding of group models, we describe group structures which enable
correct model selection in polynomial time via dynamic programming.
Furthermore, group structures that lead to totally unimodular constraints have
tractable discrete as well as convex relaxations. We also present a
generalization of the group-model that allows for within group sparsity, which
can be used to model hierarchical sparsity. Finally, we study the Pareto
frontier of group-sparse approximations for two tractable models, among which
the tree sparsity model, and illustrate selection and computation trade-offs
between our framework and the existing convex relaxations.


title: Electron pairing in periodic potentials under an external electric field

abstract:
  We study the semiclassical dynamics of interacting electrons in a biased
crystal lattice. A complex dynamical scenario emerges from the interplay
between the Coulomb and the external electric fields. When the electrons are
far apart, the Coulomb potential may be small compared to the external
potential and the electrons oscillate with effective Bloch frequencies,
determined by the local electric field. In the opposite case, nearby electrons
either separate or form a bound pair, depending on the initial energy compared
to the band width. The pair due to the Coulomb field is stable even in the
absence of the external field.


title:
Comparison of different approaches to the longitudinal momentum spread
  after tunnel ionization

abstract:
  We introduce a method to investigate the longitudinal momentum spread
resulting from strong-field tunnel ionization of Helium which, unlike other
methods, is valid for all ellipticities of laser pulse. Semiclassical models
consisting of tunnel ionization followed by classical propagation in the
combined ion and laser field reproduce the experimental results if an initial
longitudinal spread at the tunnel exit is included. The values for this spread
are found to be of the order of twice the transverse momentum spread.


title:
Case study of Rb+(aq), quasi-chemical theory of ion hydration, and the
  no split occupancies rule

abstract:
  Quasi-chemical theory applied to ion hydration combines statistical
mechanical theory, electronic structure calculations, and molecular simulation,
disciplines which are individually subjects for specialized professional
attention. Because it combines activities which are themselves non-trivial,
quasi-chemical theory is typically viewed with surprise. Nevertheless, it
provides a fully-considered framework for analysis of ion hydration.
Furthermore, the initial calculations are indeed simple, successful, and
provide new information to long-standing experimental activities such as
neutron diffraction by hydrated ions. Here we review quasi-chemical theory in
the context of a challenging application, Rb+(aq).


title: Carbon in the Draco Dwarf Spheroidal Galaxy

abstract:
  Measurements of [C/Fe], [Ca/H], and [Fe/H] have been derived from Keck I
LRISb spectra of 35 giants in the Draco dwarf spheroidal galaxy. The iron
abundances are derived by a spectrum synthesis modeling of the wavelength
region from 4850 to 5375 A, while calcium and carbon abundances are obtained by
fitting the Ca II H and K lines and the CH G band respectively. A range in
metallicity of -2.9 <= [Fe/H]} <= -1.6 is found within the giants sampled, with
a good correlation between [Fe/H] and [Ca/H]. The great majority of stars in
the sample would be classified as having weak absorption in the lambda 3883 CN
band, with only a small scatter in band strengths at a given luminosity on the
red giant branch. In this sense the behavior of CN among the Draco giants is
consistent with the predominantly weak CN bands found among red giants in
globular clusters of metallicity [Fe/H] < -1.8. Over half of the giants in the
Draco sample have [Fe/H] > -2.25, and among these there is a trend for the
[C/Fe] abundance to decrease with increasing luminosity on the red giant
branch. This is a phenomenon that is also seen among both field and globular
cluster giants of the Galactic halo, where it has been interpreted as a
consequence of deep mixing of material between the base of the convective
envelope and the outer limits of the hydrogen-burning shell. However, among the
six Draco giants observed that turn out to have metallicities -2.65 < [Fe/H] <
-2.25 there is no such trend seen in the carbon abundance. This may be due to
small sample statistics or primordial inhomogeneities in carbon abundance among
the most metal-poor Draco stars. We identify a potential carbon-rich extremely
metal-poor star in our sample. This candidate will require follow up
observations for confirmation.


title:
Non-adiabatic motional effects and dissipative blockade for Rydberg
  atoms excited from optical lattices or microtraps

abstract:
  The laser-excitation of Rydberg atoms in ultracold gases is often described
assuming that the atomic motion is frozen during the excitation time. We show
that this frozen gas approximation can break down for atoms that are held in
optical lattices or microtraps. In particular, we show that the excitation
dynamics is in general strongly affected by mechanical forces among the Rydberg
atoms as well as the spread of the atomic wavepacket in the confining
potential. This causes decoherence in the excitation dynamics - resulting in a
dissipative blockade effect - that renders the Rydberg excitation inefficient
even in the anti-blockade regime. For a strongly off-resonant laser excitation
- usually considered in the context of Rydberg dressing - these motional
effects compromise the applicability of the Born-Oppenheimer approximation. In
particular, our results indicate that they can lead to decoherence also in the
dressing regime.


title:
Quasiperiodic oscillations and homoclinic orbits in the nonlinear
  nonlocal Schr\"odinger equation

abstract:
  Quasiperiodic oscillations and shape-transformations of higher-order bright
solitons in nonlinear nonlocal media have been frequently observed in recent
years, however, the origin of these phenomena was never completely elucidated.
In this paper, we perform a linear stability analysis of these higher-order
solitons by solving the Bogoliubov-de Gennes equations. This enables us to
understand the emergence of a new oscillatory state as a growing unstable mode
of a higher-order soliton. Using dynamically important states as a basis, we
provide low-dimensional visualizations of the dynamics and identify
quasiperiodic and homoclinic orbits, linking the latter to
shape-transformations.


title:
Heat Diode Effect and Negative Differential Thermal Conductance across
  Nanoscale Metal-Dielectric Interfaces

abstract:
  Controlling heat flow by phononic nanodevices has received significant
attention recently because of its fundamental and practical implications.
Elementary phononic devices such as thermal rectifiers, transistors, and logic
gates are essentially based on two intriguing properties: heat diode effect and
negative differential thermal conductance. However, little is known about these
heat transfer properties across metal-dielectric interfaces, especially at
nanoscale. Here we analytically resolve the microscopic mechanism of the
nonequilibrium nanoscale energy transfer across metal-dielectric interfaces,
where the inelastic electron-phonon scattering directly assists the energy
exchange. We demonstrate the emergence of heat diode effect and negative
differential thermal conductance in nanoscale interfaces and explain why these
novel thermal properties are usually absent in bulk metal-dielectric
interfaces. These results will generate exciting prospects for the nanoscale
interfacial energy transfer, which should have important implications in
designing hybrid circuits for efficient thermal control and open up potential
applications in thermal energy harvesting with low-dimensional nanodevices.


title:
Cosmological perturbations in theories with non-minimal coupling between
  curvature and matter

abstract:
  In this work, one examines how the presence of a non-minimal coupling between
the spacetime curvature and matter affects the evolution of cosmological
perturbations around a homogeneous and isotropic Universe and hence the
formation of large-scale structure. This framework places constraints on the
terms which arise due to the coupling with matter and, in particular, on the
modification in the growth of matter density perturbations. One obtains
approximate analytical solutions for the evolution of matter overdensities
during the matter dominated era and shows that these favor the presence of a
coupling function that is compatible with the late-time cosmic acceleration.


title:
Jointly interventional and observational data: estimation of
  interventional Markov equivalence classes of directed acyclic graphs

abstract:
  In many applications we have both observational and (randomized)
interventional data. We propose a Gaussian likelihood framework for joint
modeling of such different data-types, based on global parameters consisting of
a directed acyclic graph (DAG) and correponding edge weights and error
variances. Thanks to the global nature of the parameters, maximum likelihood
estimation is reasonable with only one or few data points per intervention. We
prove consistency of the BIC criterion for estimating the interventional Markov
equivalence class of DAGs which is smaller than the observational analogue due
to increased partial identifiability from interventional data. Such an
improvement in identifiability has immediate implications for tighter bounds
for inferring causal effects. Besides methodology and theoretical derivations,
we present empirical results from real and simulated data.


title: A note on diastatic entropy and balanced metrics

abstract:
  We give un upper bound Ent(\Omega, g)<\lambda\ of the diastatic entropy
Ent(\Omega, g) of a complex bounded domain (\Omega, g) in terms of the balanced
condition (in Donaldson terminology) of the Kaehler metric \lambda g. When
(\Omega, g) is a homogeneous bounded domain we show that the converse holds
true, namely if Ent(\Omega, g)<1 then g is balanced. Moreover, we explcit
compute Ent(\Omega, g) in terms of Piatetski-Shapiro constants.


title: Slow light with three-level atoms in metamaterial waveguides

abstract:
  Metamaterial is promising for enhancing the capability of plasmonic devices.
We consider a cylindrical waveguide with three-level \Lambda\ atoms embedded in
the dielectric core. By comparing metal cladding vs metamaterial cladding of a
waveguide with \Lambda\ atoms in the core, we show that, for a fixed amount of
slowing of light due to electromagnetically induced transparency, the
metamaterial cladding outperforms in terms of the inherent loss.


title:
Viscosity solution of Hamilton-Jacobi equation by a limiting minmax
  method

abstract:
  For non convex Hamiltonians, the viscosity solution and the more geometric
minimax solution of the Hamilton-Jacobi equation do not coincide in general.
They are nevertheless related: we show that iterating the minimax procedure
during shorter and shorter time intervals one recovers the viscosity solution.


title:
Energy levels, radiative rates and electron impact excitation rates for
  transitions in He-like Ga XXX, Ge XXXI, As XXXII, Se XXXIII and Br XXXIV

abstract:
  We report calculations of energy levels, radiative rates and electron impact
excitation cross sections and rates for transitions in He-like Ga XXX, Ge XXXI,
As XXXII, Se XXXIII and Br XXXIV. The {\sc grasp} (general-purpose relativistic
atomic structure package) is adopted for calculating energy levels and
radiative rates. For determining the collision strengths, and subsequently the
excitation rates, the Dirac Atomic R-matrix Code ({\sc darc}) is used.
Oscillator strengths, radiative rates and line strengths are reported for all
E1, E2, M1 and M2 transitions among the lowest 49 levels of each ion.
Additionally, theoretical lifetimes are provided for all 49 levels of the above
five ions. Collision strengths are averaged over a Maxwellian velocity
distribution and the effective collision strengths obtained listed over a wide
temperature range up to 10$^{8}$ K. Comparisons are made with similar data
obtained using the Flexible Atomic Code ({\sc fac}) to highlight the importance
of resonances, included in calculations with {\sc darc}, in the determination
of effective collision strengths. Discrepancies between the collision strengths
from {\sc darc} and {\sc fac}, particularly for some forbidden transitions, are
also discussed. Finally, discrepancies between the present results for
effective collision strengths with the {\sc darc} code and earlier
semi-relativistic $R$-matrix data are noted over a wide range of electron
temperatures for many transitions in all ions.


title: A twist in the M24 moonshine story

abstract:
  Prompted by the Mathieu Moonshine observation, we identify a pair of
45-dimensional vector spaces of states that account for the first order term in
the massive sector of the elliptic genus of K3 in every Z2-orbifold CFT on K3.
These generic states are uniquely characterized by the fact that the action of
every geometric symmetry group of a Z2-orbifold CFT yields a well-defined
faithful representation on them. Moreover, each such representation is obtained
by restriction of the 45-dimensional irreducible representation of the Mathieu
group M24 constructed by Margolin. Thus we provide a piece of evidence for
Mathieu Moonshine explicitly from SCFTs on K3.
  The 45-dimensional irreducible representation of M24 exhibits a twist, which
we prove can be undone in the case of Z2-orbifold CFTs on K3 for all geometric
symmetry groups. This twist however cannot be undone for the combined symmetry
group Z2^4 : A8 that emerges from surfing the moduli space of Kummer K3s. We
conjecture that in general, the untwisted representations are exclusively those
of geometric symmetry groups in some geometric interpretation of a CFT on K3.
In that light, the twist appears as a representation theoretic manifestation of
the maximality constraints in Mukai's classification of geometric symmetry
groups of K3.


title:
On the largest real root of independence polynomials of graphs, an
  ordering on graphs, and starlike trees

abstract:
  Let $G$ be a simple graph of order $n$. An independent set in a graph is a
set of pairwise non-adjacent vertices. The independence polynomial of $G$ is
the polynomial $I(G,x)=\sum_{k=0}^{n} s(G,k) x^{k}$, where $s(G,k)$ is the
number of independent sets of $G$ of size $k$ and $s(G,0)=1$. Clearly all real
roots of $I(G,x)$ are negative. Let $\xi(G)$ be the largest real root of
$I(G,x)$. Let $H$ be a simple graph. By $G \succeq H$ we mean that $I(H,x)\geq
I(G,x)$ for every $x$ in the interval $[\xi(G),0]$. We note that $G\succeq H$
implies that $\xi(G)\geq \xi(H)$. Also we let $G\succ H$ if and only if
$G\succeq H$ and $I(G,x)\neq I(H,x)$. We prove that for every tree $T$ of order
$n$, $S_n\succeq T\succeq P_n$, where $S_n$ and $P_n$ are the star and the path
of order n, respectively. By $T=T(n_1,\ldots,n_k)$ we mean a tree $T$ which has
a vertex $v$ of degree $k$ such that $T\setminus v=P_{n_1-1}+\cdots+P_{n_k-1}$,
that is $T\setminus v$ is the disjoint union of the paths
$P_{n_1-1},\ldots,P_{n_k-1}$. Let $X=(x_1,\ldots,x_k)$ and
$Y=(y_1,\ldots,y_k)$, where $x_1\geq \cdots\geq x_k$ and $y_1\geq\cdots\geq
y_k$ are real. By $X\succ Y$, we mean $x_1=y_1,\ldots,x_{t-1}=y_{t-1}$ and
$x_t>y_t$ for some $t\in\{1,\ldots,k\}$. We let $X\succ_{d}Y$, if $X\neq Y$ and
for every $j$, $1\leq j\leq k$, $\sum_{i=1}^{j}x_i\geq \sum_{i=1}^{j}y_i$.
Among all trees with fixed number of vertices, we show that if
$(m_1,\ldots,m_k)\succ_{d}(n_1,\ldots,n_k)$, then $T(n_1,\ldots,n_k)\succ
T(m_1,\ldots,m_k)$. We conjecture that $T(n_1,\ldots,n_k)\succ
T(m_1,\ldots,m_k)$ if and only if $(m_1,\ldots,m_k)\succ (n_1,\ldots,n_k)$,
where $\sum_{i=1}^kn_i=\sum_{i=1}^km_i$.


title: Phase transitions and gluodynamics in 2-colour matter at high density

abstract:
  We investigate 2-colour QCD with 2 flavours of Wilson fermion at nonzero
temperature T and quark chemical potential mu, with a pion mass of 700 MeV
(m_pi/m_rho=0.8). From temperature scans at fixed mu we find that the critical
temperature for the superfluid to normal transition depends only very weakly on
mu above the onset chemical potential, while the deconfinement crossover
temperature is clearly decreasing with mu. We find indications of a region of
superfluid but deconfined matter at high mu and intermediate T. The static
quark potential determined from the Wilson loop is found to exhibit a 'string
tension' that increases at large mu in the 'deconfined' region. The electric
(longitudinal) gluon propagator in Landau gauge becomes strongly screened with
increasing temperature and chemical potential. The magnetic (transverse) gluon
shows little sensitivity to temperature, and exhibits a mild enhancement at
intermediate mu before becoming suppressed at large mu.


title: The Scale of Inflation in the Landscape

abstract:
  We determine the frequency of regions of small-field inflation in the Wigner
landscape as an approximation to random supergravities/type IIB flux
compactifications. We show that small-field inflation occurs exponentially more
often than large-field inflation The power of primordial gravitational waves
from inflation is generically tied to the scale of inflation. For small-field
models this is below observational reach. However, we find small-field
inflation to be dominated by the highest inflationary energy scales compatible
with a sub-Planckian field range. Hence, we expect a typical tensor-to-scalar
ratio $r\sim {\cal O}(10^{-3})$ currently undetectable in upcoming CMB
measurements.


title:
Dimensional regularization of local singularities in the 4th
  post-Newtonian two-point-mass Hamiltonian

abstract:
  The article delivers the only still unknown coefficient in the 4th
post-Newtonian energy expression for binary point masses on circular orbits as
function of orbital angular frequency. Apart from a single coefficient, which
is known solely numerically, all the coefficients are given as exact numbers.
The shown Hamiltonian is presented in the center-of-mass frame and out of its
57 coefficients 51 are given fully explicitly. Those coefficients are six
coefficients more than previously achieved [Jaranowski/Sch\"afer, Phys. Rev. D
86, 061503(R) (2012)]. The local divergences in the point-mass model are
uniquely controlled by the method of dimensional regularization. As
application, the last stable circular orbit is determined as function of the
symmetric-mass-ratio parameter.


title: On near and the nearest correlation matrix

abstract:
  We present an elementary heuristic reasoning based on Arnold's theory of
versal deformations in support of a straightforward algorithm for finding a
correlation matrix near a given symmetric one.


title: On the potential role of the Collins effect in A_N in pp --> pion X

abstract:
  Transverse single spin asymmetries in pp --> pion X processes, while on a
quite firm ground experimentally, are still a much debated phenomenological
issue. We consider them in a transverse momentum dependent factorization
scheme. After revisiting a previous result, we give new estimates of the
Collins contribution by adopting the latest information on the Collins and
transversity functions, as extracted from SIDIS and e+e- data.


title: Ferromagnetic quantum critical point in UCo1-xFexGe

abstract:
  We have carried out a comprehensive study of the UCo1-xFexGe series across
the entire range of compositions 0 <= x <= 1, and report the results of x-ray
diffraction, magnetization, specific heat, and electrical resistivity to
uncover the T-x phase diagram. Substitution of Fe into UCoGe initially results
in an increase in the Curie temperature and a rapid destruction of the
superconductivity. Near x = 0.22, the ferromagnetic transition is suppressed to
zero temperature at an apparent ferromagnetic itinerant electron quantum
critical point, where the temperature dependence of the electrical resistivity
and specific heat in this region reveal non-Fermi liquid behavior.


title: FindZebra: A search engine for rare diseases

abstract:
  Background: The web has become a primary information resource about illnesses
and treatments for both medical and non-medical users. Standard web search is
by far the most common interface for such information. It is therefore of
interest to find out how well web search engines work for diagnostic queries
and what factors contribute to successes and failures. Among diseases, rare (or
orphan) diseases represent an especially challenging and thus interesting class
to diagnose as each is rare, diverse in symptoms and usually has scattered
resources associated with it. Methods: We use an evaluation approach for web
search engines for rare disease diagnosis which includes 56 real life
diagnostic cases, state-of-the-art evaluation measures, and curated information
resources. In addition, we introduce FindZebra, a specialized (vertical) rare
disease search engine. FindZebra is powered by open source search technology
and uses curated freely available online medical information. Results:
FindZebra outperforms Google Search in both default setup and customised to the
resources used by FindZebra. We extend FindZebra with specialized
functionalities exploiting medical ontological information and UMLS medical
concepts to demonstrate different ways of displaying the retrieved results to
medical experts. Conclusions: Our results indicate that a specialized search
engine can improve the diagnostic quality without compromising the ease of use
of the currently widely popular web search engines. The proposed evaluation
approach can be valuable for future development and benchmarking. The FindZebra
search engine is available at http://www.findzebra.com/.


title:
The thermohaline, Richardson, Rayleigh-Taylor, Solberg-Hoiland, and GSF
  criteria in rotating stars

abstract:
  Aims. We examine the interactions of various instabilities in rotating stars,
which usually are considered as independent. Methods. An analytical study of
the problem is performed, account is given to radiative losses, mu-gradients
and horizontal turbulence. Results. The diffusion coefficient for an ensemble
of instabilities is not given by the sum of the specific coefficients for each
instability, but by the solution of a general equation. We find that
thermohaline mixing is possible in low-mass red giants only if the horizontal
turbulence is very weak. In rotating stars the Rayleigh-Taylor and the shear
instabilities need simultaneous treating. This has for consequence that
rotation laws of the form 1/r^(alpha) are predicted to be unstable for alpha >
1.6568, while the usual Rayleigh criterion predicts instability only for alpha
> 2. Also, the shear instabilities are somehow reduced in Main Sequence stars
by the effect of the Rayleigh-Taylor criterion. Various instability criteria
should be expressed differently in rotating stars than in simplified
geometries.


title: A compendium of Lie structures on tensor products

abstract:
  We demonstrate how a simple linear-algebraic technique used earlier to
compute low-degree cohomology of current Lie algebras, can be utilized to
compute other kinds of structures on such Lie algebras, and discuss further
generalizations, applications, and related questions. While doing so, we touch
upon such seemingly diverse topics as associative algebras of infinite
representation type, Hom-Lie structures, Poisson brackets of hydrodynamic type,
Novikov algebras, simple Lie algebras in small characteristics, and Koszul dual
operads.


title:
Front tracking and iterated minmax for Hamilton-Jacobi equation in one
  space variable

abstract:
  The viscosity solution of the Hamilton-Jacobi equation was constructed by an
"iterated minimax" procedure. Using Dafermos' front tracking method, we give
another proof of this construction in the case of Hamilton-Jacobi equations in
one space dimension. This allows us to get a better understanding in this case
of the singularities of the viscosity solution.


title:
Consistency Checking and Querying in Probabilistic Databases under
  Integrity Constraints

abstract:
  We address the issue of incorporating a particular yet expressive form of
integrity constraints (namely, denial constraints) into probabilistic
databases. To this aim, we move away from the common way of giving semantics to
probabilistic databases, which relies on considering a unique interpretation of
the data, and address two fundamental problems: consistency checking and query
evaluation. The former consists in verifying whether there is an interpretation
which conforms to both the marginal probabilities of the tuples and the
integrity constraints. The latter is the problem of answering queries under a
"cautious" paradigm, taking into account all interpretations of the data in
accordance with the constraints. In this setting, we investigate the complexity
of the above-mentioned problems, and identify several tractable cases of
practical relevance.


title:
Radiative improvement of the lattice NRQCD action using the background
  field method with applications to quarkonium spectroscopy

abstract:
  We apply the background field (BF) method to Non-Relativistic QCD (NRQCD) on
the lattice in order to determine the one-loop radiative corrections to the
coefficients of the NRQCD action in a manifestly gauge-covariant manner by
matching the NRQCD prediction for particular on-shell processes with those of
relativistic continuum QCD. We explain how the BF method is implemented in
automated perturbation theory and discuss the technique for matching the
relativistic and non-relativistic theories. We compute the one-loop radiative
corrections to the sigma.B and Darwin terms for the NRQCD action currently used
in simulations, as well as the one-loop coefficients of the spin-dependent
O(alpha^2) four-fermion contact terms. The effect of the corrections on the
hyperfine splitting of bottomonium is estimated using earlier simulation
results; the corrected lattice prediction is found to be in agreement with
experiment. Agreement of the hyperfine splitting of bottomonium and the B-meson
system is confirmed by recent simulation studies (Dowdall et al.) which include
our NRQCD radiative corrections for the first time.


title: On the Entropy of Couplings

abstract:
  In this paper, some general properties of Shannon information measures are
investigated over sets of probability distributions with restricted marginals.
Certain optimization problems associated with these functionals are shown to be
NP-hard, and their special cases are found to be essentially
information-theoretic restatements of well-known computational problems, such
as the SUBSET SUM and the 3-PARTITION. The notion of minimum entropy coupling
is introduced and its relevance is demonstrated in information-theoretic,
computational, and statistical contexts. Finally, a family of pseudometrics (on
the space of discrete probability distributions) defined by these couplings is
studied, in particular their relation to the total variation distance, and a
new characterization of the conditional entropy is given.


title: Singularity analysis via the iterated kernel method

abstract:
  In the quarter plane, five lattice path models with unit steps have resisted
the otherwise general approach of Fayolle, Rachel, and Kurkova. Here we
consider these five models, called the singular models, and prove that the
generating functions marking the number of walks of a given length are not
D-finite -- thus finishing the proof of a conjecture of Bousquet-M\'elou and
Mishna. Furthermore, we provide exact and asymptotic enumerative formulas for
the number of such walks.


title: Plane waves as tractor beams

abstract:
  It is shown that in a large class of systems plane waves can act as tractor
beams: i.e., an incident plane wave can exert a pulling force on the scatterer.
The underlying physical mechanism for the pulling force is due to the
sufficiently strong scattering of the incoming wave into another mode having a
larger wave number, in which case excess momentum is created behind the
scatterer. Such a tractor beam or negative radiation pressure effect arises
naturally in systems where the coupling between the scattering channels is due
to Aharonov-Bohm (AB) gauge potentials. It is demonstrated that this effect is
also present if the AB potential is an induced, ("artificial") gauge potential
such as the one found in J. March-Russell, J. Preskill, F. Wilczek, Phys. Rev.
Lett. 58 2567 (1992).


title:
Vacuum polarisation on the brane for a higher dimensional black hole
  spacetime

abstract:
  We present the vacuum polarisation of a massless, conformally coupled scalar
field on the brane for a Schwarzschild-Tangherlini black hole in a bulk of zero
to seven additional dimensions.


title:
Measurement of associated production of vector bosons and top
  quark-antiquark pairs at sqrt(s) = 7 TeV

abstract:
  The first measurement of vector-boson production associated with a top
quark-antiquark pair in proton-proton collisions at sqrt(s) = 7 TeV is
presented. The results are based on a data set corresponding to an integrated
luminosity of 5.0 inverse femtobarms, recorded by the CMS detector at the LHC
in 2011. The measurement is performed in two independent channels through a
trilepton analysis of t t-bar Z events and a same-sign dilepton analysis of t
t-bar V (V = W or Z) events. In the trilepton channel a direct measurement of
the t t-bar Z cross section sigma(t t-bar Z) = 0.28 +0.14/-0.11 (stat)
+0.06/-0.03 (syst) pb is obtained. In the dilepton channel a measurement of the
t t-bar V cross section yields sigma(t t-bar V) = 0.43 +0.17/-0.15 (stat)
+0.09/-0.07 (syst) pb. These measurements have a significance, respectively, of
3.3 and 3.0 standard deviations from the background hypotheses and are
compatible, within uncertainties, with the corresponding next-to-leading order
predictions of 0.137 +0.012/-0.016 and 0.306 +0.031/-0.053 pb.


title: A Unified Framework for Probabilistic Component Analysis

abstract:
  We present a unifying framework which reduces the construction of
probabilistic component analysis techniques to a mere selection of the latent
neighbourhood, thus providing an elegant and principled framework for creating
novel component analysis models as well as constructing probabilistic
equivalents of deterministic component analysis methods. Under our framework,
we unify many very popular and well-studied component analysis algorithms, such
as Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA),
Locality Preserving Projections (LPP) and Slow Feature Analysis (SFA), some of
which have no probabilistic equivalents in literature thus far. We firstly
define the Markov Random Fields (MRFs) which encapsulate the latent
connectivity of the aforementioned component analysis techniques; subsequently,
we show that the projection directions produced by all PCA, LDA, LPP and SFA
are also produced by the Maximum Likelihood (ML) solution of a single joint
probability density function, composed by selecting one of the defined MRF
priors while utilising a simple observation model. Furthermore, we propose
novel Expectation Maximization (EM) algorithms, exploiting the proposed joint
PDF, while we generalize the proposed methodologies to arbitrary connectivities
via parameterizable MRF products. Theoretical analysis and experiments on both
simulated and real world data show the usefulness of the proposed framework, by
deriving methods which well outperform state-of-the-art equivalents.


title:
Scale-Invariant Curvature Fluctuations from an Extended Semiclassical
  Gravity

abstract:
  We present an extension of the semiclassical Einstein equations which couples
n-point correlation functions of a stochastic Einstein tensor to the n-point
functions of the quantum stress-energy tensor. We apply this extension to
calculate the quantum fluctuations during an inflationary period, where we take
as a model a massive conformally coupled scalar field on a perturbed de Sitter
space and describe how a renormalization independent, almost-scale-invariant
power spectrum of the scalar metric perturbation is produced. Furthermore, we
discuss how this model yields a natural basis for the calculation of
non-Gaussianities of the considered metric fluctuations.


abstract:
  We introduce Random Matrix Models for the Hermitian Wilson-Dirac operator of
QCD-like theories. We show that they are equivalent to the $\epsilon$-limit of
the chiral Lagrangian for Wilson chiral perturbation theory. Results are
obtained for two-color QCD with quarks in the fundamental representation of the
color group as well as any-color QCD with quarks in the adjoint representation.
For $N_c=2$ we also have obtained the lattice spacing dependence of the
quenched average spectral density for a fixed value of the index of the Dirac
operator. Comparisons with direct numerical simulations of the random matrix
ensemble are shown.


title: Supersymmetric Models on AdS3 and AdS4 Embedding Superspaces

abstract:
  Superspace techniques are used to formulate a supersymmetric model on an AdS3
surface embedded in four dimensions. In this model, the supersymmetry
transformation is the "square root" of the transformation generated by the
isometry generators of AdS3. Since momentum is not an isometry generator,
supersymmetry does not result in equal masses for a Bosonic field and its
Fermionic partner. We express this model in terms of coordinates that
characterize the AdS3 space. In one coordinate system, it is possible to define
a subspace with a Minkowski metric. It becomes possible to infer a model in
AdS4 space in which there is a symmetry transformation that relates Bosonic and
Fermionic fields. This model is not a consequence of being formulated in
superspace and the Fermionic transformation is not the "square root" of an
isometry of AdS4.


title: Position-dependent diffusion of light in disordered waveguides

abstract:
  Diffusion has been widely used to describe a random walk of particles or
waves, and it requires only one parameter -- the diffusion constant. For waves,
however, diffusion is an approximation that disregards the possibility of
interference. Anderson localization, which manifests itself through a vanishing
diffusion coefficient in an infinite system, originates from constructive
interference of waves traveling in loop trajectories -- pairs of time-reversed
paths returning to the same point. In an open system of finite size, the return
probability through such paths is reduced, particularly near the boundary where
waves may escape. Based on this argument, the self-consistent theory of
localization and the supersymmetric field theory predict that the diffusion
coefficient varies spatially inside the system. A direct experimental
observation of this effect is a challenge because it requires monitoring wave
transport inside the system. Here, we fabricate two-dimensional photonic random
media and probe position-dependent diffusion inside the sample from the third
dimension. By varying the geometry of the system or the dissipation which also
limits the size of loop trajectories, we are able to control the
renormalization of the diffusion coefficient. This work shows the possibility
of manipulating diffusion via the interplay of localization and dissipation.


title:
Flow Motifs Reveal Limitations of the Static Framework to Represent
  Human interactions

abstract:
  Networks are commonly used to define underlying interaction structures where
infections, information, or other quantities may spread. Although the standard
approach has been to aggregate all links into a static structure, some studies
suggest that the time order in which the links are established may alter the
dynamics of spreading. In this paper, we study the impact of the time ordering
in the limits of flow on various empirical temporal networks. By using a random
walk dynamics, we estimate the flow on links and convert the original
undirected network (temporal and static) into a directed flow network. We then
introduce the concept of flow motifs and quantify the divergence in the
representativity of motifs when using the temporal and static frameworks. We
find that the regularity of contacts and persistence of vertices (common in
email communication and face-to-face interactions) result on little differences
in the limits of flow for both frameworks. On the other hand, in the case of
communication within a dating site (and of a sexual network), the flow between
vertices changes significantly in the temporal framework such that the static
approximation poorly represents the structure of contacts. We have also
observed that cliques with 3 and 4 vertices con- taining only low-flow links
are more represented than the same cliques with all high-flow links. The
representativity of these low-flow cliques is higher in the temporal framework.
Our results suggest that the flow between vertices connected in cliques depend
on the topological context in which they are placed and in the time sequence in
which the links are established. The structure of the clique alone does not
completely characterize the potential of flow between the vertices.

categories: physics.soc-ph cs.SI physics.data-an q-bio.QM


title: Holographic Hierarchy in the Gaussian Matrix Model via the Fuzzy Sphere

abstract:
  The Gaussian Hermitian matrix model was recently proposed to have a dual
string description with worldsheets mapping to a sphere target space. The
correlators were written as sums over holomorphic (Belyi) maps from worldsheets
to the two-dimensional sphere, branched over three points. We express the
matrix model correlators by using the fuzzy sphere construction of matrix
algebras, which can be interpreted as a string field theory description of the
Belyi strings. This gives the correlators in terms of trivalent ribbon graphs
that represent the couplings of irreducible representations of su(2), which can
be evaluated in terms of 3j and 6j symbols. The Gaussian model perturbed by a
cubic potential is then recognised as a generating function for Ponzano-Regge
partition functions for 3-manifolds having the worldsheet as boundary, and
equipped with boundary data determined by the ribbon graphs. This can be viewed
as a holographic extension of the Belyi string worldsheets to membrane
worldvolumes, forming part of a holographic hierarchy linking, via the large N
expansion, the zero-dimensional QFT of the Matrix model to 2D strings and 3D
membranes.


title:
Performance of a random-access wireless network with a mix of full- and
  half-duplex stations

abstract:
  In this paper, we consider the performance of a random-access time-slotted
wireless network with a single access point and a mix of half- and full- duplex
stations. Full-duplex transmissions involve data transmitted simultaneously in
both directions, and this influences the dynamics of the queue at the access
point. Given the probabilities of channel access by the nodes, this paper
provides generalized analytical formulations for the throughputs for each
station. Special cases related to a 802.11 DCA based system as well as a
full-fairness system are discussed, which provide insights into the changes
introduced by the new technology of full-duplex wireless.


title: The 125 GeV boson: A composite scalar?

abstract:
  Assuming that the 125 GeV particle observed at the LHC is a composite scalar
and responsible for the electroweak gauge symmetry breaking, we consider the
possibility that the bound state is generated by a non-Abelian gauge theory
with dynamically generated gauge boson masses and a specific chiral symmetry
breaking dynamics motivated by confinement. The scalar mass is computed with
the use of the Bethe-Salpeter equation and its normalization condition as a
function of the SU(N) group and the respective fermionic representation. If the
fermions that form the composite state are in the fundamental representation of
the SU(N) group, we can generate such light boson only for one specific number
of fermions for each group. In the case of small groups, like SU(2) to SU(5),
and two fermions in the adjoint representation we find that is quite improbable
to generate such light composite scalar.


title: Dielectric response of laser-excited silicon

abstract:
  We calculate the dielectric response of crystalline silicon following
irradiation by a high-intensity laser pulse, modeling the dynamics by
time-dependent density functional theory (TDDFT). The pump-probe measurements
are numerically simulated by solving the time-dependent Kohn-Sham equation with
the pump and probe fields included as external fields. As expected, the excited
silicon shows features of a particle-hole plasma in its response. We compare
the calculated response with a thermal model and with a simple Drude model. The
thermal model requires only a static DFT calculation to prepare electronically
excited matter and agrees rather well with the TDDFT for the same particle-hole
density. The Drude model with two fitted parameters (electron effective mass
and collision time) also shows fair agreement at the lower excitation energies;
the fitted effective masses are consistent with carrier-band dispersions. The
extracted Drude lifetimes range from 6 fs at weak pumping fields to much lower
values at high fields. However, we find that the Drude model does not give a
good fit to the imaginary dielectric function at the highest fields. Comparing
the thermal model with the Drude, we find that the extracted lifetimes are in
the same range, 1-13 fs depending on the temperature. These short Drude
lifetimes show that strong damping is possible in the TDDFT, despite the
absence of electron scattering. One significant difference between the TDDFT
response and the other models is that the response to the probe pulse depends
on the polarization of the pump pulse. We also find that the imaginary part of
the dielectric function can be negative, particularly for the parallel
polarization of pump and probe fields.


title: Reconstruction of Directed Networks from Consensus Dynamics

abstract:
  This paper addresses the problem of identifying the topology of an unknown,
weighted, directed network running a consensus dynamics. We propose a
methodology to reconstruct the network topology from the dynamic response when
the system is stimulated by a wide-sense stationary noise of unknown power
spectral density. The method is based on a node-knockout, or grounding,
procedure wherein the grounded node broadcasts zero without being eliminated
from the network. In this direction, we measure the empirical cross-power
spectral densities of the outputs between every pair of nodes for both grounded
and ungrounded consensus to reconstruct the unknown topology of the network. We
also establish that in the special cases of undirected or purely unidirectional
networks, the reconstruction does not need grounding. Finally, we extend our
results to the case of a directed network assuming a general dynamics, and
prove that the developed method can detect edges and their direction.


title: Multi-Stage Robust Chinese Remainder Theorem

abstract:
  It is well-known that the traditional Chinese remainder theorem (CRT) is not
robust in the sense that a small error in a remainder may cause a large error
in the reconstruction solution. A robust CRT was recently proposed for a
special case when the greatest common divisor (gcd) of all the moduli is more
than 1 and the remaining integers factorized by the gcd of all the moduli are
co-prime. In this special case, a closed-form reconstruction from erroneous
remainders was proposed and a necessary and sufficient condition on the
remainder errors was obtained. It basically says that the reconstruction error
is upper bounded by the remainder error level $\tau$ if $\tau$ is smaller than
a quarter of the gcd of all the moduli. In this paper, we consider the robust
reconstruction problem for a general set of moduli. We first present a
necessary and sufficient condition for the remainder errors for a robust
reconstruction from erroneous remainders with a general set of muduli and also
a corresponding robust reconstruction method. This can be thought of as a
single stage robust CRT. We then propose a two-stage robust CRT by grouping the
moduli into several groups as follows. First, the single stage robust CRT is
applied to each group. Then, with these robust reconstructions from all the
groups, the single stage robust CRT is applied again across the groups. This is
then easily generalized to multi-stage robust CRT. Interestingly, with this
two-stage robust CRT, the robust reconstruction holds even when the remainder
error level $\tau$ is above the quarter of the gcd of all the moduli. In this
paper, we also propose an algorithm on how to group a set of moduli for a
better reconstruction robustness of the two-stage robust CRT in some special
cases.


title: The Choquet boundary of an operator system

abstract:
  We show that every operator system (and hence every unital operator algebra)
has sufficiently many boundary representations to generate the C*-envelope.


title:
Wall-crossing structures in Donaldson-Thomas invariants, integrable
  systems and Mirror Symmetry

abstract:
  We introduce the notion of Wall-Crossing Structure and discuss it in several
examples including complex integrable systems, Donaldson-Thomas invariants and
Mirror Symmetry.
  For a big class of non-compact Calabi-Yau 3-folds we construct complex
integrable systems of Hitchin type with the base given by the moduli space of
deformations of those 3-folds. Then Donaldson-Thomas invariants of the Fukaya
category of such a Calabi-Yau 3-fold can be (conjecturally) described in two
more ways: in terms of the attractor flow on the base of the corresponding
complex integrable system and in terms of the skeleton of the mirror dual to
the total space of the integrable system.
  The paper also contains a discussion of some material related to the main
subject, e.g. Betti model of Hitchin systems with irregular singularities, WKB
asymptotics of connections depending on a small parameter, attractor points in
the moduli space of complex structures of a compact Calabi-Yau 3-fold, relation
to cluster varieties, etc.


title:
Second-order differentiability for solutions of elliptic equations in
  the plane

abstract:
  For a second-order elliptic equation of nondivergence form in the plane, we
investigate conditions on the coefficients which imply that all strong
solutions have first-order derivatives that are Lipschitz continuous or
differentiable at a given point. We assume the coefficients have modulus of
continuity satisfying the square-Dini condition, and obtain additional
conditions associated with a dynamical system that is derived from the
coefficients of the elliptic equation. Our results extend those of previous
authors who assume the modulus of continuity satisfies the Dini condition.


title: Sheaves, Cosheaves and Applications

abstract:
  This thesis develops the theory of sheaves and cosheaves with an eye towards
applications in science and engineering. To provide a theory that is
computable, we focus on a combinatorial version of sheaves and cosheaves called
cellular sheaves and cosheaves, which are finite families of vector spaces and
maps parametrized by a cell complex. We develop cellular (co)sheaves as a new
tool for topological data analysis, network coding and sensor networks. A
foundation for multi-dimensional level-set persistent homology is laid via
constructible cosheaves, which are equivalent to representations of
MacPherson's entrance path category. By proving a van Kampen theorem, we give a
direct proof of this equivalence. A cosheaf version of the i'th derived
pushforward of the constant sheaf along a definable map is constructed directly
as a representation of this category. We go on to clarify the relationship of
cellular sheaves to cosheaves by providing a formula that defines a derived
equivalence, which in turn recovers Verdier duality. Compactly-supported sheaf
cohomology is expressed as the coend with the image of the constant sheaf
through this equivalence. The equivalence is further used to establish
relations between sheaf cohomology and a herein newly introduced theory of
cellular sheaf homology. Inspired to provide fast algorithms for persistence,
we prove that the derived category of cellular sheaves over a 1D cell complex
is equivalent to a category of graded sheaves. Finally, we introduce the
interleaving distance as an extended pseudo-metric on the category of sheaves.
We prove that global sections partition the space of sheaves into connected
components. We conclude with an investigation into the geometry of the space of
constructible sheaves over the real line, which we relate to the bottleneck
distance in persistence.


title:
Structural Results and Explicit Solution for Two-Player LQG Systems on a
  Finite Time Horizon

abstract:
  It is well-known that linear dynamical systems with Gaussian noise and
quadratic cost (LQG) satisfy a separation principle. Finding the optimal
controller amounts to solving separate dual problems; one for control and one
for estimation. For the discrete-time finite-horizon case, each problem is a
simple forward or backward recursion. In this paper, we consider a
generalization of the LQG problem in which there are two controllers. Each
controller is responsible for one of two system inputs, but has access to
different subsets of the available measurements. Our paper has three main
contributions. First, we prove a fundamental structural result: sufficient
statistics for the controllers can be expressed as conditional means of the
global state. Second, we give explicit state-space formulae for the optimal
controller. These formulae are reminiscent of the classical LQG solution with
dual forward and backward recursions, but with the important difference that
they are intricately coupled. Lastly, we show how these recursions can be
solved efficiently, with computational complexity comparable to that of the
centralized problem.


title: Ranking and combining multiple predictors without labeled data

abstract:
  In a broad range of classification and decision making problems, one is given
the advice or predictions of several classifiers, of unknown reliability, over
multiple questions or queries. This scenario is different from the standard
supervised setting, where each classifier accuracy can be assessed using
available labeled data, and raises two questions: given only the predictions of
several classifiers over a large set of unlabeled test data, is it possible to
a) reliably rank them; and b) construct a meta-classifier more accurate than
most classifiers in the ensemble? Here we present a novel spectral approach to
address these questions. First, assuming conditional independence between
classifiers, we show that the off-diagonal entries of their covariance matrix
correspond to a rank-one matrix. Moreover, the classifiers can be ranked using
the leading eigenvector of this covariance matrix, as its entries are
proportional to their balanced accuracies. Second, via a linear approximation
to the maximum likelihood estimator, we derive the Spectral Meta-Learner (SML),
a novel ensemble classifier whose weights are equal to this eigenvector
entries. On both simulated and real data, SML typically achieves a higher
accuracy than most classifiers in the ensemble and can provide a better
starting point than majority voting, for estimating the maximum likelihood
solution. Furthermore, SML is robust to the presence of small malicious groups
of classifiers designed to veer the ensemble prediction away from the (unknown)
ground truth.


title: Power-law cosmologies in minimal and maximal gauged supergravity

abstract:
  In this paper we search for accelerating power-law solutions and ekpyrotic
solutions within minimal and maximal four dimensional supergravity theories. We
focus on the STU model for N=1 and on the new CSO(p,q,r) theories, which were
recently obtained exploiting electromagnetic duality, for N=8. In the minimal
case we find some new ekpyrotic solutions, while in the maximal case we find
some new generic power-law solutions. We do not find any new accelerating
solutions for these models.


title: Gravitational wave constraints on the shape of neutron stars

abstract:
  We show that there is a direct relation between upper limits on (or potential
future measurements of) the m = 2 quadrupole moments of slowly rotating neutron
stars and the l = m = 2 deformation of the star's surface, in full general
relativity, to first order in the perturbation. This relation only depends on
the star's structure through its mass and radius. All one has to assume about
the star's constituents is that the stress-energy tensor at its surface is that
of a perfect fluid, which will be true with good accuracy in almost all the
situations of interest, and that the magnetic field configuration there is
force-free, which is likely to be a good approximation. We then apply this
relation to the stars which have direct LIGO/Virgo bounds on their m = 2
quadrupole moment, below the spin-down limit, and compare with the expected
surface deformations due to rotation. In particular, we find that LIGO
observations have constrained the Crab pulsar's l = m = 2 surface deformation
to be smaller than its l = 2, m = 0 deformation due to rotation, for all the
causal equations of state we consider, a statement that would not have been
able to be made just using the upper bounds on the l = m = 2 deformation from
electromagnetic observations.


title:
The inverse problem of pure point diffraction -- examples and open
  questions

abstract:
  This paper considers some open questions related to the inverse problem of
pure point diffraction, in particular, what types of objects may diffract, and
which of these may exhibit the same diffraction. Some diverse objects with the
same simple lattice diffraction are constructed, including a tempered
distribution that is not a measure, and it is shown that there are uncountably
many such objects in the diffraction solution class of any pure point
diffraction measure with an infinite supporting set.


title: The Haagerup property for locally compact quantum groups

abstract:
  The Haagerup property for locally compact groups is generalised to the
context of locally compact quantum groups, with several equivalent
characterisations in terms of the unitary representations and positive-definite
functions established. In particular it is shown that a locally compact quantum
group G has the Haagerup property if and only if its mixing representations are
dense in the space of all unitary representations. For discrete G we
characterise the Haagerup property by the existence of a symmetric proper
conditionally negative functional on the dual quantum group $\hat{G}$; by the
existence of a real proper cocycle on G, and further, if G is also unimodular
we show that the Haagerup property is a von Neumann property of G. This extends
results of Akemann, Walter, Bekka, Cherix, Valette, and Jolissaint to the
quantum setting and provides a connection to the recent work of Brannan. We use
these characterisations to show that the Haagerup property is preserved under
free products of discrete quantum groups.


title:
Information theoretically secure, enhanced Johnson noise based key
  distribution over the smart grid with switched filters

abstract:
  We introduce a protocol with a reconfigurable filter system to create
non-overlapping single loops in the smart power grid for the realization of the
Kirchhoff-Law-Johnson-(like)-Noise secure key distribution system. The protocol
is valid for one-dimensional radial networks (chain-like power line) which are
typical of the electricity distribution network between the utility and the
customer. The speed of the protocol (the number of steps needed) versus grid
size is analyzed. When properly generalized, such a system has the potential to
achieve unconditionally secure key distribution over the smart power grid of
arbitrary geometrical dimensions.


title:
Performance Analysis of LMS Filter for SSPA Linearization in Different
  Modulation Conditions

abstract:
  The SSPA has wide application in Communication system, but its high output
power varies due to its non linear gain. Pre-distortion method plays major role
in power amplifier linearization. Polynomial is one of the methods used. The
error estimation in Polynomial method is carried out by LMS Filter. Our main
work is to analysis the error estimation performance of the LMS Filter for the
Solid state power amplifiers (SSPA) in different modulation conditions. Here we
are calculating the ACP and analyzing how effectively the memoryless non
linearity has been reduced for all digital modulation techniques. All the
analysis and results are taken using Matlab software.


title: Electromagnetic wave propagation through inhomogeneous material layers

abstract:
  We use Maxwell's equations in a sourceless, inhomogeneous medium with
continuous permeability $\mu (\mathbf{r}) $ and permittivity $% \epsilon
(\mathbf{r}) $ to study the wave propagation. The general form of the wave
equation is derived and by virtue of some physical assumptions, including $\mu
$ and $\epsilon $ as functions of $z,$ the equation has been simplified.
Finally by introducing a smooth step dielectric variable we solve the wave
equation in the corresponding medium which is in conform with the well known
results. Exact double-layer solution in analytic form has been given in terms
of the Heun functions.


title:
A dependent partition-valued process for multitask clustering and time
  evolving network modelling

abstract:
  The fundamental aim of clustering algorithms is to partition data points. We
consider tasks where the discovered partition is allowed to vary with some
covariate such as space or time. One approach would be to use
fragmentation-coagulation processes, but these, being Markov processes, are
restricted to linear or tree structured covariate spaces. We define a
partition-valued process on an arbitrary covariate space using Gaussian
processes. We use the process to construct a multitask clustering model which
partitions datapoints in a similar way across multiple data sources, and a time
series model of network data which allows cluster assignments to vary over
time. We describe sampling algorithms for inference and apply our method to
defining cancer subtypes based on different types of cellular characteristics,
finding regulatory modules from gene expression data from multiple human
populations, and discovering time varying community structure in a social
network.


title: A theory of turbulence based on scale relativity

abstract:
  The internal interactions of fluids occur at all scales therefore the
resulting force fields have no reason to be smooth and differentiable. The
release of the differentiability hypothesis has important mathematical
consequences, like scale dependence and the use of a higher algebra. The law of
mechanics transfers directly these properties to the velocity of fluid
particles whose trajectories in velocity space become fractal and
non-deterministic. The principle of relativity is used to find the form of the
equation governing velocity in scale space. The solution of this equation
contains a fractal and a non-fractal term. The fractal part is shown to be
equivalent to the Lagrangian version of the Kolmogorov law of fully-developed
and isotropic turbulence. It is therefore associated with turbulence, whereas
the non-fractal deterministic term is associated with a laminar behavior. These
terms are found to be balanced when the typical velocity reaches a level at
which the Reynolds number is equal to one, in agreement with the empirical
observations. The rate of energy dissipated by turbulence in a flow passing an
obstacle that was only known from experiments can be derived theoretically from
the equation's solution. Finally, a quantum-like equation in velocity space is
proposed in order to find the probability of having a given velocity at a given
location. It may eventually explain the presence of large scale coherent
structures in geophysical turbulent flows, like jet-streams.


title: Unveiling the nature of the unidentified gamma-ray sources

abstract:
  One of the main scientific objectives of the recent Fermi mission is
investigating the origin of the unidentified gamma-ray sources (UGSs). Despite
the large improvements of Fermi in the gamma-ray source localization with
respect to the past gamma-ray missions, about 1/3 of the gamma-ray objects
detected do not have yet an assigned counterpart a low energies. We recently
developed a new association method to identify if there is a gamma-ray blazar
candidate within the positional uncertainty region of a generic gamma-ray
source. This method is entirely based on the discovery that blazars, the
largest known class of gamma-ray sources, can be recognized and separated from
other extragalactic sources on the basis of their infrared colors. Here we
summarize the results obtained by applying our association procedure to the
unidentified gamma-ray sources (UGSs) and to the active galaxies of uncertain
type (AGUs) listed in the Second Fermi Large Area Telescope (LAT) catalog.


title:
The New Milky Way: a wide-field survey of optical transients near the
  Galactic plane

abstract:
  Currently, it may take days for a bright nova outburst to be detected. With
the few exceptions, little is known about novae behaviour prior to maximum
light. A theoretically-predicted population of ultra-fast novae with t2<1d is
evading observational discovery because it is not possible to routinely
organize fast follow-up observations of nova candidates. With the aim of
brining the detection time of novae and other bright (V<13.5) optical
transients from days down to hours or less, we develop an automated wide-field
(8x6 deg.) system capable of surveying the whole Milky Way area visible from
the observing site in one night. The system is built using low-cost
mass-produced components and the transient detection pipeline is based on the
open source VaST software. We describe the instrument design and report results
of the first observations conducted in October-November 2011 and January-April
2012. The results include the discovery of Nova Sagittarii 2012 No. 1 as well
as two X-ray emitting cataclysmic variables 1RXS J063214.8+25362 and XMMSL1
J014956.7+533504. The rapid detection of Nova Sagittarii 2012 No. 1 enabled us
to conduct its X-ray and UV observations with Swift 22 hours after discovery
(~31 hour after the outburst onset). All images obtained during the transient
search survey are available online.


title: Asymmetric Diffusion of Magnetic Field Lines

abstract:
  Stochasticity of magnetic field lines is important for particle transport
properties. Magnetic field lines separate faster than diffusively in turbulent
plasma, which is called superdiffusion. We discovered that this superdiffusion
is pronouncedly asymmetric, so that the separation of field lines along the
magnetic field direction is different from the separation in the opposite
direction. While the symmetry of the flow is broken by the so-called imbalance
or cross-helicity, the difference between forward and backward diffusion is not
directly due to imbalance, but a non-trivial consequence of both imbalance and
non-reversibility of turbulence. The asymmetric diffusion perpendicular to the
mean magnetic field entails a variety of new physical phenomena, such as the
production of parallel particle streaming in the presence of perpendicular
particle gradients. Such streaming and associated instabilities could be
significant for particle transport in laboratory, space and astrophysical
plasmas.


title: Magnetar giant flare oscillations and the nuclear symmetry energy

abstract:
  If the observed quasi-periodic oscillations in magnetar flares are partially
confined to the crust, then the oscillation frequencies are unique probes of
the nuclear physics of the neutron star crust. We study crustal oscillations in
magnetars including corrections for a finite Alfven velocity. Our crust model
uses a new nuclear mass formula that predicts nuclear masses with an accuracy
very close to that of the finite range droplet model. This mass model for
equilibrium nuclei also includes shell corrections and an updated neutron-drip
line. We perturb our crust model to predict axial crust modes and assign them
to observed giant flare quasi-periodic oscillation frequencies from the soft
gamma-ray repeater SGR 1806-20. We find magnetar crusts that match observations
for various magnetic field strengths, entrainment of the free neutron gas in
the inner crust, and crust-core transition densities. We find that observations
can be reconciled with smaller values of the symmetry energy slope parameter,
L, if there is a significant amount of entrainment of the neutrons by the
superfluid or if the crust-core transition density is large. We also find
neutron star masses and radii which are in agreement with expectations from
what is known about low-density matter from nuclear experiment. Matching
observations with a field-free model we obtain the approximate values of M
=1.35 Msun and R = 11.9 km. Matching observations using a model with the
surface dipole field of SGR 1806-20 (B=2.4x10^15 G) we obtain the approximate
values of M = 1.25 Msun and R = 12.4 km.


title: A Dark-Disk Universe

abstract:
  We point out that current constraints on dark matter imply only that the
majority of dark matter is cold and collisionless. A subdominant fraction of
dark matter could have much stronger interactions. In particular, it could
interact in a manner that dissipates energy, thereby cooling into a
rotationally-supported disk, much as baryons do. We call this proposed new dark
matter component Double-Disk Dark Matter (DDDM). We argue that DDDM could
constitute a fraction of all matter roughly as large as the fraction in
baryons, and that it could be detected through its gravitational effects on the
motion of stars in galaxies, for example. Furthermore, if DDDM can annihilate
to gamma rays, it would give rise to an indirect detection signal distributed
across the sky that differs dramatically from that predicted for ordinary dark
matter. DDDM and more general partially interacting dark matter scenarios
provide a large unexplored space of testable new physics ideas.


title:
A High-Significance Measurement of Correlation Between Unresolved IRAS
  Sources and Optically-Selected Galaxy Clusters

abstract:
  We cross-correlate the 100 um Improved Reprocessing of the IRAS Survey (IRIS)
map and galaxy clusters at 0.1 < z < 0.3 in the maxBCG catalogue taken from the
Sloan Digital Sky Survey, measuring an angular cross-power spectrum over
multipole moments 150 < l < 3000 at a total significance of over 40 sigma. The
cross-spectrum, which arises from the spatial correlation between unresolved
dusty galaxies that make up the cosmic infrared background (CIB) in the IRIS
map and the galaxy clusters, is well-fit by a single power law with an index of
-1.28 +/- 0.12, similar to the clustering of unresolved galaxies from
cross-correlating far-infrared and submillimetre maps at longer wavelengths.
Using a recent, phenomenological model for the spectral and clustering
properties of the IRIS galaxies, we constrain the large-scale bias of the
maxBCG clusters to be 2.6 +/- 1.4, consistent with existing analyses of the
real-space cluster correlation function. The success of our method suggests
that future CIB-optical cross-correlations using Planck and Herschel data will
significantly improve our understanding of the clustering and redshift
distribution of the faint CIB sources.


title: Scattering in Time-Dependent Basis Light-Front Quantization

abstract:
  We introduce a nonperturbative, first principles numerical approach for
solving time-dependent problems in quantum field theory, using light-front
quantization. As a first application we consider QED in a strong background
field, and the process of non-linear Compton scattering in which an electron is
excited by the background and emits a photon. We track the evolution of the
quantum state as a function of time. Observables, such as the invariant mass of
the electron-photon pair, are first checked against results from perturbation
theory, for suitable parameters. We then proceed to a test case in the strong
background field regime and discuss the various nonperturbative effects
revealed by the approach.


title: Masses of galaxy clusters from gravitational lensing

abstract:
  Despite consistent progress in numerical simulations, the observable
properties of galaxy clusters are difficult to predict ab initio. It is
therefore important to compare both theoretical and observational results to a
direct measure of the cluster mass. This can be done by measuring the
gravitational lensing effects caused by the bending of light by the cluster
mass distribution. In this review we discuss how this phenomenon can be used to
determine cluster masses and study the mass distribution itself. As sample
sizes increase, the accuracy of the weak lensing mass estimates needs to
improve accordingly. We discuss the main practical aspects of these
measurements. We review a number of applications and highlight some recent
results.


title:
Ferromagnetic exchange, spin-orbit coupling and spiral magnetism at the
  LaAlO_3/SrTiO_3 interface

abstract:
  The electronic properties of the polar interface between insulating oxides is
a subject of great current interest. An exciting new development is the
observation of robust magnetism at the interface of two non-magnetic materials
LaAlO_3 (LAO) and SrTiO_3 (STO). Here we present a microscopic theory for the
formation and interaction of local moments, which depends on essential features
of the LAO/STO interface. We show that correlation-induced moments arise due to
interfacial splitting of orbital degeneracy. We find that gate-tunable Rashba
spin-orbit coupling at the interface influences the exchange interaction
mediated by conduction electrons. We predict that the zero-field ground state
is a long-wavelength spiral and show that its evolution in an external field
accounts semi-quantitatively for torque magnetometry data. Our theory describes
qualitative aspects of the scanning SQUID measurements and makes several
testable predictions for future experiments.


title:
Search for ZH -> l+l- bbar production in 9.7 fb-1 of ppbar collisions
  with the D0 detector

abstract:
  We present a search for the standard model (SM) Higgs boson produced in
association with a Z boson in 9.7 fb-1 of ppbar collisions collected with the
D0 detector at the Fermilab Tevatron Collider at sqrt{s} = 1.96 TeV. Selected
events contain one reconstructed Z -> e+e- or Z -> mu+mu- candidate and at
least two jets, including at least one jet likely to contain a b quark. To
validate the search procedure, we also measure the cross section for ZZ
production, and find that it is consistent with the SM expectation. We set
upper limits at the 95% C.L. on the product of the ZH production cross section
and branching ratio B(H -> bbbar) for Higgs boson masses 90 <= M_H <= 150 GeV.
The observed (expected) limit for M_H = 125 GeV is a factor of 7.1 (5.1) larger
than the SM prediction.


title: The peripatric coalescent

abstract:
  We consider a dynamic metapopulation involving one large population of size N
surrounded by colonies of size \varepsilon_NN, usually called peripheral
isolates in ecology, where N\to\infty and \varepsilon_N\to 0 in such a way that
\varepsilon_NN\to\infty. The main population periodically sends propagules to
found new colonies (emigration), and each colony eventually merges with the
main population (fusion). Our aim is to study the genealogical history of a
finite number of lineages sampled at stationarity in such a metapopulation. We
make assumptions on model parameters ensuring that the total outer population
has size of the order of N and that each colony has a lifetime of the same
order. We prove that under these assumptions, the scaling limit of the
genealogical process of a finite sample is a censored coalescent where each
lineage can be in one of two states: an inner lineage (belonging to the main
population) or an outer lineage (belonging to some peripheral isolate).
Lineages change state at constant rate and inner lineages (only) coalesce at
constant rate per pair. This two-state censored coalescent is also shown to
converge weakly, as the landscape dynamics accelerate, to a time-changed
Kingman coalescent.


title:
Effects of Nuclear Vibrations on the Energetics of Polythiophene:
  Quantized Energy Molecular Dynamics

abstract:
  Effects of nuclear dynamics on the energetics of polythiophene relevant for
the performance of organic solar cells are studied for the first time. Nuclear
motions change the expectation values of frontier orbital energies and the band
gap by about 0.1 eV vs. values at the equilibrium geometry, which is expected
to have a significant effect on light absorption, charge separation, and donor
regeneration. A new molecular dynamics (MD) algorithm, which accounts for the
quantum nature of vibrations, is introduced. It reproduces effects of
temperature and deuteration which are lost in the standard MD. Inclusion of
quantized vibrations leads to a broadening of the band gap and of energy levels
by about 20% at 300K, while having little effect on their expectation values
(which change by up to 0.03 eV). Increase in temperature from 300K to 400K and
deuteration cause an additional broadening of the spectrum by about 26% and
21%, respectively.


title:
Perturbative expansion of the energy of static sources at large orders
  in four-dimensional SU(3) gauge theory

abstract:
  We determine the infinite volume coefficients of the perturbative expansions
of the self-energies of static sources in the fundamental and adjoint
representations in SU(3) gluodynamics to order \alpha^{20} in the strong
coupling parameter \alpha. We use numerical stochastic perturbation theory,
where we employ a new second order integrator and twisted boundary conditions.
The expansions are obtained in lattice regularization with the Wilson action
and two different discretizations of the covariant time derivative within the
Polyakov loop. Overall, we obtain four different perturbative series. For all
of them the high order coefficients display the factorial growth predicted by
the conjectured renormalon picture, based on the operator product expansion.
This enables us to determine the normalization constants of the leading
infrared renormalons of heavy quark and heavy gluino pole masses and to
translate these into the modified minimal subtraction scheme (MS). We also
estimate the four-loop \beta-function coefficient of the lattice scheme.


title:
Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet
  Atmosphere

abstract:
  Determining the atmospheric structure and chemical composition of an
exoplanet remains a formidable goal. Fortunately, advancements in the study of
exoplanets and their atmospheres have come in the form of direct imaging -
spatially resolving the planet from its parent star - which enables
high-resolution spectroscopy of self-luminous planets in Jovian-like orbits.
Here, we present a spectrum with numerous, well-resolved, molecular lines from
both water and carbon monoxide from a massive planet orbiting less than 40 AU
from the star HR 8799. These data reveal the planet's chemical composition,
atmospheric structure, and surface gravity, confirming that it is indeed a
young planet. The spectral lines suggest an atmospheric carbon-to-oxygn ratio
greater than the host star's, providing hints about the planet's formation.


title:
Geometric Phase and Fidelity of The One-Dimensional Extended Quantum
  Compass Model in a Transverse Field

abstract:
  We study the geometric phase of the ground state in the extended quantum
compass model in presence of a transverse field. The exact solution is obtained
by using the Jordan-Wigner transformation which maps the Hamiltonian on a
fermionic system and applying the Fourier transformation to realize the
diagonalization and an analytical expression for the ground state and geometric
phase in the momentum space. Furthermore, the scaling behavior of the extremum
of geometric phase and its universality are investigated due to the divergence
of geometric phase at the critical point.


title:
The hottest superfluid and superconductor in the Universe: Discovery and
  nuclear physics implications

abstract:
  We present recent work on using astronomical observations of neutron stars to
reveal unique insights into nuclear matter that cannot be obtained from
laboratories on Earth. First, we discuss our measurement of the rapid cooling
of the youngest neutron star in the Galaxy; this provides the first direct
evidence for superfluidity and superconductivity in the supra-nuclear core of
neutron stars. We show that observations of thermonuclear X-ray bursts on
neutron stars can be used to constrain properties of neutron superfluidity and
neutrino emission. We describe the implications of rapid neutron star rotation
rates on aspects of nuclear and superfluid physics. Finally, we show that
entrainment coupling between the neutron superfluid and the nuclear lattice
leads to a less mobile crust superfluid; this result puts into question the
conventional picture of pulsar glitches as being solely due to the crust
superfluid and suggests that the core superfluid also participates.


title:
Electric control of a $\{Fe_4\}$ single-molecule magnet in a
  single-electron transistor

abstract:
  Using first-principles methods we study theoretically the properties of an
individual $\{Fe_4\}$ single-molecule magnet (SMM) attached to metallic leads
in a single-electron transistor geometry. We show that the conductive leads do
not affect the spin ordering and magnetic anisotropy of the neutral SMM. On the
other hand, the leads have a strong effect on the anisotropy of the charged
states of the molecule, which are probed in Coulomb blockade transport.
Furthermore, we demonstrate that an external electric potential, modeling a
gate electrode, can be used to manipulate the magnetic properties of the
system. For a charged molecule, by localizing the extra charge with the gate
voltage closer to the magnetic core, the anisotropy magnitude and spin ordering
converges to the values found for the isolated $\{Fe_4\}$ SMM. We compare these
findings with the results of recent quantum transport experiments in
three-terminal devices.


title:
Constraining dark matter annihilation with the isotropic $\gamma$-ray
  background: updated limits and future potential

abstract:
  The nature of the Isotropic $\gamma$-ray Background (IGRB) measured by the
Large Area Telescope (LAT) on the Fermi $\gamma$-ray space Telescope ({\it
Fermi}) remains partially unexplained. Non-negligible contributions may
originate from extragalactic populations of unresolved sources such as blazars,
star-forming galaxies or galactic milli-second pulsars. A recent prediction of
the diffuse $\gamma$-ray emission from Active Galactic Nuclei (AGN) with a
large viewing angle with respect to the line-of-sight (l.o.s.) has demonstrated
that this faint but numerous population is also expected to contribute
significantly to the total IGRB intensity. A more exotic contribution to the
IGRB invokes the pair annihilation of dark matter (DM) weakly interacting
massive particles (WIMPs) into $\gamma$-rays. In this work, we evaluate the
room left for galactic DM at high latitudes ($>10^\circ$) by including photons
from both prompt emission and inverse Compton scattering, emphasizing the
impact of the newly discovered contribution from misaligned AGN (MAGN) for such
an analysis. Summing up all significant galactic and extragalactic components
of the IGRB, we find that an improved understanding of the associated
astrophysical uncertainties is still mandatory to put stringent bounds on
thermally produced DM. On the other hand, we also demonstrate that the IGRB has
the potential to be one of the most competitive {\it future} ways to test the
DM WIMP hypothesis, once the present uncertainties are even slightly reduced.
In fact, if MAGN contribute even at 90% of the maximal level consistent with
our current understanding, thermally produced WIMPs would be severely
constrained as DM candidates for masses up to several TeV.


title: Internal Cluster Structure

abstract:
  The core structure of galaxy clusters is fundamentally important. Even though
self-gravitating systems have no stable equilibrium state due to their negative
heat capacity, numerical simulations find density profiles which are universal
in the sense that they are fairly flat within a scale radius and gradually
steepen farther outward, asymptotically approaching a logarithmic slope of
$\approx-3$ near the virial radius. We argue that the reason for the formation
of this profile is not satisfactorily understood. The ratio between the virial
radius and the scale radius, the so-called concentration, is found in
simulations to be closely related to the mass and the redshift and low for
cluster-sized haloes, but observed to be substantially higher at least in a
subset of observed clusters. Haloes formed from cold dark matter should
furthermore be richly substructured. We review theoretical and observational
aspects of cluster cores here, discuss modifications by baryonic physics and
observables that can provide better insight into the internal structure of
clusters.


title: Outskirts of Galaxy Clusters

abstract:
  Until recently, only about 10% of the total intracluster gas volume had been
studied with high accuracy, leaving a vast region essentially unexplored. This
is now changing and a wide area of hot gas physics and chemistry awaits
discovery in galaxy cluster outskirts. Also, robust large-scale total mass
profiles and maps are within reach. First observational and theoretical results
in this emerging field have been achieved in recent years with sometimes
surprising findings. Here, we summarize and illustrate the relevant underlying
physical and chemical processes and review the recent progress in X-ray,
Sunyaev--Zel'dovich, and weak gravitational lensing observations of cluster
outskirts, including also brief discussions of technical challenges and
possible future improvements.


title:
How (not) to assess the importance of correlations for the matching of
  spontaneous and evoked activity: a response

abstract: A response to a comment of Fiser et al.


title: Quantum Periods for 3-Dimensional Fano Manifolds

abstract:
  The quantum period of a variety X is a generating function for certain
Gromov-Witten invariants of X which plays an important role in mirror symmetry.
In this paper we compute the quantum periods of all 3-dimensional Fano
manifolds. In particular we show that 3-dimensional Fano manifolds with very
ample anticanonical bundle have mirrors given by a collection of Laurent
polynomials called Minkowski polynomials. This was conjectured in joint work
with Golyshev. It suggests a new approach to the classification of Fano
manifolds: by proving an appropriate mirror theorem and then classifying Fano
mirrors.
  Our methods are likely to be of independent interest. We rework the
Mori-Mukai classification of 3-dimensional Fano manifolds, showing that each of
them can be expressed as the zero locus of a section of a homogeneous vector
bundle over a GIT quotient V/G, where G is a product of groups of the form
GL_n(C) and V is a representation of G. When G=GL_1(C)^r, this expresses the
Fano 3-fold as a toric complete intersection; in the remaining cases, it
expresses the Fano 3-fold as a tautological subvariety of a Grassmannian,
partial flag manifold, or projective bundle thereon. We then compute the
quantum periods using the Quantum Lefschetz Hyperplane Theorem of
Coates-Givental and the Abelian/non-Abelian correspondence of
Bertram-Ciocan-Fontanine-Kim-Sabbah.


title: The incompressible fluid revisited: vortex-sound interactions

abstract:
  We study the dynamics of a nearly incompressible fluid via (classical)
effective field theory. In the kinematical regime corresponding to near
incompressibility (small fluid velocities and accelerations), compressional
modes are, by definition, difficult to excite, and can be dealt with
perturbatively. We systematically outline the corresponding perturbative
expansion, which can be thought of as an expansion in the ratio of fluid
velocity and speed of sound. Our analysis is fully relativistic, but, if
desired, the non-relativistic limit can be taken at any stage. We demonstrate
the potential of our method by some sample calculations: the relativistic
corrections to the emission and to the scattering of sound by vorticose
(possibly turbulent) motions, and, more interestingly, the vortex-vortex long
range interaction mediated by sound. These results are, to our knowledge, new.
For the last one, we find a 1/r^3 potential between localized vortex
configurations (e.g., vortex rings), whose strength and detailed structure
depend on a certain multipole moment of the vortices under consideration. We
also improve on the so-called vortex filament model, by providing a local field
theory describing the dynamics of vortex-line systems and their interaction
with sound, to all orders in perturbation theory.


title:
Kitaev-Heisenberg models for iridates on the triangular, hyperkagome,
  kagome, fcc, and pyrochlore lattices

abstract:
  The Kitaev-Heisenberg (KH) model has been proposed to capture magnetic
interactions in iridate Mott insulators on the honeycomb lattice. We show that
analogous interactions arise in many other geometries built from edge-sharing
IrO_6 octahedra, including the pyrochlore and hyperkagome lattices relevant to
Ir2O4 and Na4Ir3O8 respectively. The Kitaev spin liquid exact solution does not
generalize to these lattices. However, a different exactly soluble point of the
honeycomb lattice KH model, obtained by a four-sublattice transformation to a
ferromagnet, generalizes to all these lattices. A Klein four-group =Z2xZ2
structure is associated with this mapping (hence Klein duality). A finite
lattice admits the duality if a simple geometrical condition is met. This
duality predicts fluctuation free ordered states on these different 2D and 3D
lattices, which are analogs of the honeycomb lattice KH stripy order. This
result is used in conjunction with a semiclassical Luttinger-Tisza
approximation to obtain phase diagrams for KH models on the different lattices.
We also discuss a Majorana fermion based mean field theory at the Kitaev point,
which is exact on the honeycomb lattice, for the KH models on the different
lattices. We attribute the rich behavior of these models to the interplay of
geometric frustration and frustration induced by spin-orbit coupling.


title: Transversity: theory and phenomenology

abstract:
  The distribution of transversely polarized quarks inside a transversely
polarized nucleon, known as transversity, encodes a basic piece of information
on the nucleon structure, sharing the same status with the more familiar
unpolarized and helicity distributions. I will review its properties and
discuss different ways to access it, with highlights and limitations. Recent
phenomenological extractions and perspectives are also presented.


title: A New Absolute Magnitude Calibration for Red Clump Stars

abstract:
  We present an M_V absolute magnitude calibration including the B-V colour and
[Fe/H] metallicity for the red clump stars in the globular and open clusters
with a wide range of metallicities: M_V =
0.627(0.104)(B-V)o+0.046(0.043)[Fe/H]+0.262(0.111). The calibration equation is
valid in the ranges 0.42<(B-V)o<1.20 mag, -1.55<[Fe/H]<+0.40 dex and
0.43<M_V<1.03 mag. We found that the consistencies in the comparisons of the
distances estimated from the calibration equation in this study both with the
distances obtained from trigonometric parallaxes and spectrophotometric
analysis demonstrate that reliable precise absolute magnitudes for the clump
giants can be estimated from the calibration formula.


title: Spectrum of the Laplacian on radial graphs

abstract:
  We prove that if $M$ is a complete hypersurface in $\mathbb{R}^{n+1}$ which
is graph of a real radial function, then the spectrum of the Laplace operator
on M is the interval $[0,\infty)$.


title: Exploring \nu_\tau - \nu_s mixing with cascade events in DeepCore

abstract:
  The atmospheric neutrino data collected by the IceCube experiment and its
low-energy extension DeepCore provide a unique opportunity to probe the
neutrino sector of the Standard Model. In the low energy range the experiment
have observed neutrino oscillations, and the high energy data are especially
sensitive to signatures of new physics in the neutrino sector. In this context,
we previously demonstrated the unmatched potential of the experiment to reveal
the existence of light sterile neutrinos. The studies are routinely performed
in the simplest 3+1 model concentrating on disappearance of muon neutrinos of
TeV energy as a result of their mixing with a sterile neutrino. We here extend
this analysis to include cascade events that are secondary electromagnetic and
hadronic showers produced by neutrinos of all flavors. We find that it is
possible to probe the complete parameter space of 3+1 model, including the
poorly constrained mixing of the sterile neutrino to tau neutrinos. We show
that $\nu_\tau-\nu_s$ mixing results into a unique signature in the data that
will allow IceCube to obtain constraints well below the current upper limits.


title: The emergence of Hopf term and the marginality of Dirac model

abstract:
  The subtle relation of the marginality of Dirac model and the emergence of
the Hopf term through a Yukawa-type interaction is revealed in this work. We
show that the improvement of the marginality of Dirac mode through an
infinitesimal non-relativistic term, which is irrelevant for renormalization
group, is necessary to emerge the Hopf term. It is found that the appearance of
the Hopf term is always accompanied with chiral boundary modes, and the sign of
the coupling constant of the infinitesimal non-relativistic term decides their
chirality. A lattice Dirac model is also constructed to realize the Hopf term.