title: Loop corrections to Delta N_eff in large volume models

abstract:
  In large volume models reheating is driven by the decays of the volume
modulus to the visible sector, while the decays to its axion partners result in
dark radiation. In this article we discuss the impact of loop corrections on
the only model-independent visible decay channel: the decay into Higgs pairs
via a Giudice-Masiero term. Including such radiative effects leads to a more
precise determination of the relative fraction of dark radiation, since by
contrast all loop corrections to the volume axion decay mode are Planck
suppressed. Assuming an MSSM spectrum and that the Giudice-Masiero coupling is
fixed at the string scale by a shift symmetry in the Higgs sector, we arrive at
a prediction for the effective number of neutrinos. The result turns out to be
too large to be consistent with data, highly disfavouring the minimal model.


title: Jump-diffusion processes in random environments

abstract:
  In this paper we investigate jump-diffusion processes in random environments
which are given as the weak solutions to SDE's. We formulate conditions
ensuring existence and uniqueness in law of solutions. We investigate Markov
property. To prove uniqueness we solve a general martingale problem for \cadlag
processes. This result is of independent interest. In the last section we
present application of our results considering generalized exponential Levy
model.


title: Belief Propagation for Linear Programming

abstract:
  Belief Propagation (BP) is a popular, distributed heuristic for performing
MAP computations in Graphical Models. BP can be interpreted, from a variational
perspective, as minimizing the Bethe Free Energy (BFE). BP can also be used to
solve a special class of Linear Programming (LP) problems. For this class of
problems, MAP inference can be stated as an integer LP with an LP relaxation
that coincides with minimization of the BFE at ``zero temperature". We
generalize these prior results and establish a tight characterization of the LP
problems that can be formulated as an equivalent LP relaxation of MAP
inference. Moreover, we suggest an efficient, iterative annealing BP algorithm
for solving this broader class of LP problems. We demonstrate the algorithm's
performance on a set of weighted matching problems by using it as a cutting
plane method to solve a sequence of LPs tightened by adding ``blossom''
inequalities.


title: Zero-nonzero and real-nonreal sign determination

abstract:
  We consider first the zero-nonzero determination problem, which consists in
determining the list of zero-nonzero conditions realized by a finite list of
polynomials on a finite set Z included in C^k with C an algebraic closed field.
We describe an algorithm to solve the zero-nonzero determination problem and we
perform its bit complexity analysis. This algorithm, which is in many ways an
adaptation of the methods used to solve the more classical sign determination
problem, presents also new ideas which can be used to improve sign
determination. Then, we consider the real-nonreal sign determination problem,
which deals with both the sign determination and the zero-nonzero determination
problem. We describe an algorithm to solve the real-nonreal sign determination
problem, we perform its bit complexity analysis and we discuss this problem in
a parametric context.


title:
Risk-minimization and hedging claims on a jump-diffusion market model,
  Feynman-Kac Theorem and PIDE

abstract:
  At first, we solve a problem of finding a risk-minimizing hedging strategy on
a general market with ratings. Next, we find a solution to this problem on
Markovian market with ratings on which prices are influenced by additional
factors and rating, and behavior of this system is described by SDE driven by
Wiener process and compensated Poisson random measure and claims depend on
rating. To find a tool to calculate hedging strategy we prove a Feynman-Kac
type theorem. This result is of independent interest and has many applications,
since it enables to calculate some conditional expectations using related
PIDE's. We illustrate our theory on two examples of market. The first is a
general exponential L\'{e}vy model with stochastic volatility, and the second
is a generalization of exponential L\'{e}vy model with regime-switching.


title:
Social Network Generation and Role Determination Based on Smartphone
  Data

abstract:
  We deal with the problem of automatically generating social networks by
analyzing and assessing smartphone usage and interaction data. We start by
assigning weights to the different types of interactions such as messaging,
email, phone calls, chat and physical proximity. Next, we propose a ranking
algorithm which recognizes the pattern of interaction taking into account the
changes in the collected data over time. Both algorithms are based on recent
findings from social network research.


title:
A large anisotropy in the sky distribution of 3CRR quasars and other
  radio galaxies

abstract:
  We report the presence of large anisotropies in the sky distributions of
powerful extended quasars as well as some other sub-classes of radio galaxies
in the 3CRR survey, the most reliable and most intensively studied complete
sample of strong steep-spectrum radio sources. The anisotropies lie about a
plane passing through the equinoxes and the north celestial pole. Out of a
total of 48 quasars in the sample, 33 of them lie in one half of the observed
sky and the remaining 15 in the other half. The probability that in a random
distribution of 3CRR quasars in the sky, statistical fluctuations could give
rise to an asymmetry in observed numbers up to this level is only $\sim 1\%$.
Also only about 1/4th of Fanaroff-Riley 1 (FR1) type of radio galaxies lie in
the first half of the observed sky and the remainder in the second half. If we
include all the observed asymmetries in the sky distributions of quasars and
radio galaxies in the 3CRR sample, the probability of their occurrence by a
chance combination reduces to $\sim 2 \times 10^{-5}$. Two pertinent but
disturbing questions that could be raised here are -- firstly why should there
be such large anisotropies present in the sky distribution of some of the
strongest and most distant discrete sources, implying inhomogeneities in the
universe at very large scales (covering a fraction of the universe)? Secondly
why should such anisotropies lie about a great circle decided purely by the
orientation of earth's rotation axis and/or the axis of its revolution around
the sun? Are these alignments a mere coincidence or do they imply that these
axes have a preferential placement in the larger scheme of things, implying an
apparent breakdown of the Copernican principle or its more generalization,
cosmological principle, upon which the standard cosmological model is based
upon?


title: A new stochastic mode reduction strategy for dissipative systems

abstract:
  We present a new methodology for studying non-Hamiltonian nonlinear systems
based on an information theoretic extension of a renormalization group
technique using a modified maximum entropy principle. We obtain a rigorous
dimensionally reduced description for such systems. The neglected degrees of
freedom by this reduction are replaced by a systematically deefined stochastic
process under a constraint on the second moment. This then forms the basis of a
computationally efficient method. Numerical computations for the generalized
Kuramoto-Sivashinsky equation sup- port our method and reveal that the
long-time underlying stochastic process of the fast (unresolved) modes obeys a
universal distribution which does not depend on the initial conditions and
which we rigorously derive by the maximum entropy principle.


title:
Breakdown of a renormalized perturbation expansion around mode-coupling
  theory of the glass transition

abstract:
  We analyze a renormalized perturbation expansion around the mode-coupling
theory of the glass transition. We focus on the long-time limit of the
irreducible memory function. We discuss a renormalized diagrammatic expansion
for this function and re-sum two infinite classes of diagrams. We show that the
resulting contributions to the irreducible memory function diverge at the
mode-coupling transition. A further re-summation of ladder diagrams constructed
by iterating these divergent contributions gives a finite result which cancels
the mode-coupling theory's expression for the irreducible memory function.


title:
First Simulations of Core- Collapse Supernovae to Supernova Remnants
  with SNSPH

abstract:
  We present the first 3-dimensional simulations following the evolution of
supernova shocks from their inception in the stellar core through the
development of a supernova remnant into the Sedov phase. Our set of simulations
use two different progenitors and two different conditions for the structure of
the circumstellar environment. These calculations demonstrate the role that
supernova instabilities (the instabilities that develop as the shock drive
through the star) play in defining the structure and long-term development of
instabilities in supernova remnants. We also present a first investigation of
the mixing between stellar and interstellar matter as the supernova evolves
into a young supernova remnant.


title: Ray transfer matrix for a spiral phase plate

abstract:
  We present a ray transfer matrix for a spiral phase plate. Using this matrix,
we determine the stability of an optical resonator made of two spiral phase
plates, and trace stable ray orbits in the resonator. Our results should be
relevant to laser physics, optical micromanipulation, quantum information and
optomechanics.


title: A characterization of saturated fusion systems over abelian 2-groups

abstract:
  Given a saturated fusion system $\mathcal{F}$ over a $2$-group $S$, we prove
that $S$ is abelian provided any element of $S$ is $\mathcal{F}$-conjugate to
an element of $Z(S)$. This generalizes a Theorem of Camina--Herzog, leading to
a significant simplification of its proof. More importantly, it follows that
any $2$-block $B$ of a finite group has abelian defect groups if all
$B$-subsections are major. Furthermore, every $2$-block with a symmetric stable
center has abelian defect groups.


title:
Graphene-Enhanced Hybrid Phase Change Materials for Thermal Management
  of Li-Ion Batteries

abstract:
  Li-ion batteries are crucial components for progress in mobile communications
and transport technologies. However, Li-ion batteries suffer from strong
self-heating, which limits their life-time and creates reliability and
environmental problems. Here we show that thermal management and the
reliability of Li-ion batteries can be drastically improved using hybrid phase
change material with graphene fillers. Conventional thermal management of
batteries relies on the latent heat stored in the phase change material as its
phase changes over a small temperature range, thereby reducing the temperature
rise inside the battery. Incorporation of graphene to the hydrocarbon-based
phase change material allows one to increase its thermal conductivity by more
than two orders of magnitude while preserving its latent heat storage ability.
A combination of the sensible and latent heat storage together with the
improved heat conduction outside of the battery pack leads to a significant
decrease in the temperature rise inside a typical Li-ion battery pack. The
described combined heat storage - heat conduction approach can lead to a
transformative change in thermal management of Li-ion and other types of
batteries.


title:
The Kraft sum as a monotone function on the refinement-ordered set of
  uniquely decipherable codes

abstract:
  The set of all uniquely decipherable (UD) codes is partially ordered by
refinement, meaning that all strings in the cruder code can be represented as
concatenations of strings taken from the finer code. The Kraft sum is a
monotone (increasing) function on this poset. In the refinement order, chains
of UD codes having the same Kraft sum are necessarily of the simple sequence
type. A characterization of UD codes in terms of equalities involving Kraft
sums is also given.


title:
Proximity-induced unconventional superconductivity in topological
  insulators

abstract:
  We study and classify the proximity-induced superconducting pairing in a
topological insulator (TI)-superconductor (SC) hybrid structure for SCs with
different symmetries. The Dirac surface state gives a coupling between
spin-singlet and spin-triplet pairing amplitudes as well as pairing that is odd
in frequency for p-wave SCs. We also find that all SCs induce pairing that is
odd in both frequency and orbital (band) index, with oddness in frequency and
orbital index being completely interchangeable. The different induced pairing
amplitudes significantly modifies the density of states in the TI surface
layer.


title: A probabilistic proof of the Open Mapping Theorem for analytic functions

abstract:
  The conformal invariance of Brownian motion is used to give a short proof of
the Open Mapping Theorem for analytic functions.


title: The Twilight of the Scientific Age

abstract:
  This brief article presents the introduction and draft of the fundamental
ideas developed at length in the book of the same title, which gives a
challenging point of view about science and its history/philosophy/sociology.
Science is in decline. After centuries of great achievements, the exhaustion of
new forms and fatigue have reached our culture in all of its manifestations
including the pure sciences. Our society is saturated with knowledge which does
not offer people any sense in their lives. There is a loss of ideals in the
search for great truths and a shift towards an anodyne specialized industry.


title: Driven Electronic States at the Surface of a Topological Insulator

abstract:
  Motivated by recent photoemission experiments on the surface of topological
insulators we compute the spectrum of driven topological surface excitations in
the presence of an external light source. We completely characterize the
spectral function of these non-equilibrium electron excitations for both linear
and circular polarizations of the incident light. We find that in the latter
case, the circularly polarized light gaps out the surface states, whereas
linear polarization gives rise to an anisotropic metal with multiple Dirac
cones. We compare the sizes of the gaps with recent pump-probe photoemission
measurements and find good agreement. We also identify theoretically several
new features in the time-dependent spectral function, such as shadow Dirac
cones.


title:
Particle production in relativistic heavy-ion collisions: A consistent
  hydrodynamic approach

abstract:
  We derive relativistic viscous hydrodynamic equations invoking the
generalized second law of thermodynamics for two different forms of the
non-equilibrium single-particle distribution function. We find that the
relaxation times in these two derivations are identical for shear viscosity but
different for bulk viscosity. These equations are used to study thermal
dilepton and hadron spectra within longitudinal scaling expansion of the matter
formed in relativistic heavy-ion collisions. For consistency, the same
non-equilibrium distribution function is used in the particle production
prescription as in the derivation of the viscous evolution equations.
Appreciable differences are found in the particle production rates
corresponding to the two non-equilibrium distribution functions. We emphasize
that an inconsistent treatment of the non-equilibrium effects influences the
particle production significantly, which may affect the extraction of transport
properties of quark-gluon plasma.


title:
Dagstuhl Report 13082: Communication Complexity, Linear Optimization,
  and lower bounds for the nonnegative rank of matrices

abstract:
  This report documents the program and the outcomes of Dagstuhl Seminar 13082
"Communication Complexity, Linear Optimization, and lower bounds for the
nonnegative rank of matrices", held in February 2013 at Dagstuhl Castle.


title: On the Peculiarities of Design: An Engineering Perspective

abstract:
  It is a fact of our existence, that no matter where we are, we most often
find ourselves either hearing, seeing, talking, or even engaged in design
related activities. Despite this reality, the notion of 'design', and in
particular 'engineering design', is often ambiguous, and at times obscure.
Thus, the transfer of knowledge of this crucial topic to engineering students
engaged in practical hands-on learning or analytical research is usually
perplexing to accomplish. In light of this, it becomes worthwhile to dissect
and reflect on the abstraction of the design process in engineering. In fact,
the aim of this article is to investigate the facets of applied design, and
elaborate on its diversity, complexity and elements. Eventually, by
concretizing this subject matter, we hope to slightly assist engineering
students in alleviating some of the vagueness associated with the principle of
design, and enhance their technical skillset during innovative conceptions.


title:
Low transverse emittance electron bunches from two-color
  laser-ionization injection

abstract:
  A method is proposed to generate low emittance electron bunches from two
color laser pulses in a laser-plasma accelerator. A two-region gas structure is
used, containing a short region of a high-Z gas (e.g., krypton) for ionization
injection, followed by a longer region of a low-Z gas for post-acceleration. A
long-laser-wavelength (e.g., 5 micron) pump pulse excites plasma wake without
triggering the inner-shell electron ionization of the high-Z gas due to low
electric fields. A short-laser-wavelength (e.g., 0.4 micron) injection pulse,
located at a trapping phase of the wake, ionizes the inner-shell electrons of
the high-Z gas, resulting in ionization-induced trapping. Compared with a
single-pulse ionization injection, this scheme offers an order of magnitude
smaller residual transverse momentum of the electron bunch, which is a result
of the smaller vector potential amplitude of the injection pulse.


title:
Dynamical Evidence for a Magnetocentrifugal Wind from a 20 Msun Binary
  Young Stellar Object

abstract:
  In Orion BN/KL, proper motions of 7 mm vibrationally-excited SiO masers trace
rotation of a nearly edge-on disk and a bipolar wide-angle outflow 10-100 AU
from radio Source I, a binary young stellar object (YSO) of ~20 Msun. Here we
map ground-state 7 mm SiO emission with the Very Large Array and track proper
motions over 9 years. The innermost and strongest emission lies in two extended
arcs bracketing Source I. The proper motions trace a northeast-southwest
bipolar outflow 100-1000 AU from Source I with a median 3D motion of ~18 km/s.
An overlying distribution of 1.3 cm H2O masers betrays similar flow
characteristics. Gas dynamics and emission morphology traced by the masers
suggest the presence of a magnetocentrifugal disk-wind. Reinforcing evidence
lies in the colinearity of the flow, apparent rotation across the flow parallel
to the disk rotation, and recollimation that narrows the flow opening angle
~120 AU downstream. The arcs of ground-state SiO emission may mark the
transition point to a shocked super-Alfvenic outflow.


title:
Monte Carlo simulations of two-dimensional fermion systems with
  string-bond states

abstract:
  We describe an application of variational Monte Carlo to two-dimensional
fermionic systems within the recently developed tensor-network string-bond
state (SBS) ansatz. We use a combination of variational Monte Carlo and
stochastic optimization to optimize the matrix-product state matrices
representing the ground state. We present results for a two-dimensional
spinless fermion model including nearest-neighbor Coulomb interactions and
determine using finite-size scaling the phase boundary between charge-ordered
insulating and metallic phases. This approach can treat frustrated systems and
be easily extended to for fermions with spin.


title: Sparse Approximate Inference for Spatio-Temporal Point Process Models

abstract:
  Spatio-temporal point process models play a central role in the analysis of
spatially distributed systems in several disciplines. Yet, scalable inference
remains computa- tionally challenging both due to the high resolution modelling
generally required and the analytically intractable likelihood function. Here,
we exploit the sparsity structure typical of (spatially) discretised
log-Gaussian Cox process models by using approximate message-passing
algorithms. The proposed algorithms scale well with the state dimension and the
length of the temporal horizon with moderate loss in distributional accuracy.
They hence provide a flexible and faster alternative to both non-linear
filtering-smoothing type algorithms and to approaches that implement the
Laplace method or expectation propagation on (block) sparse latent Gaussian
models. We infer the parameters of the latent Gaussian model using a structured
variational Bayes approach. We demonstrate the proposed framework on simulation
studies with both Gaussian and point-process observations and use it to
reconstruct the conflict intensity and dynamics in Afghanistan from the
WikiLeaks Afghan War Diary.


title:
Factored expectation propagation for input-output FHMM models in systems
  biology

abstract:
  We consider the problem of joint modelling of metabolic signals and gene
expression in systems biology applications. We propose an approach based on
input-output factorial hidden Markov models and propose a structured
variational inference approach to infer the structure and states of the model.
We start from the classical free form structured variational mean field
approach and use a expectation propagation to approximate the expectations
needed in the variational loop. We show that this corresponds to a factored
expectation constrained approximate inference. We validate our model through
extensive simulations and demonstrate its applicability on a real world
bacterial data set.


title:
Markov Chain Mote Carlo solution of BK equation through
  Newton-Kantorovich method

abstract:
  We propose a new method for Monte Carlo solution of non-linear integral
equations by combining the Newton-Kantorovich method for solving non-linear
equations with the Markov Chain Monte Carlo (MCMC) method for solving linear
equations. The Newton-Kantorovich method allows to express the non-linear
equation as a system of the linear equations which then can be treated by the
MCMC (random walk) algorithm. We apply this method to the Balitsky-Kovchegov
(BK) equation describing evolution of gluon density at low x. Results of
numerical computations show that the MCMC method is both precise and efficient.
The presented algorithm may be particularly suited for solving more complicated
and higher-dimensional non-linear integral equation, for which traditional
methods become unfeasible.


title:
SU(2) x U(1) Yang-Mills theories in 3d with Higgs field and Gribov
  ambiguity

abstract:
  We study the structure of the gauge propagators of a 3d version of the
electroweak interaction in terms of the Higgs vacuum expectation value nu, of
the non-Abelian gauge coupling g, and of the Abelian gauge coupling g', when
nonperturbative effects related to the non-Abelian gauge fixing are introduced
by means of an adapted path integral measure. In the perturbative regime of
small non-Abelian coupling g and sufficiently large nu, the well-known standard
Z and W propagators are recovered, together with a massless photon. In general,
depending on the relative magnitudes of g, g' and nu, we uncover a quite
different propagator structure. In a later stage of research, the results here
derived can be used to study the associated phase diagram in more depth.


title: Naturality in sutured monopole and instanton homology

abstract:
  Kronheimer and Mrowka defined invariants of balanced sutured manifolds using
monopole and instanton Floer homology. Their invariants assign isomorphism
classes of modules to balanced sutured manifolds. In this paper, we introduce
refinements of these invariants which assign much richer algebraic objects
called projectively transitive systems of modules to balanced sutured manifolds
and isomorphisms of such systems to diffeomorphisms of balanced sutured
manifolds. Our work provides the foundation for extending these sutured Floer
theories to other interesting functorial frameworks as well, and can be used to
construct new invariants of contact structures and (perhaps) of knots and
bordered 3-manifolds.


title: Linear response in the nonequilibrium zero range process

abstract:
  We explore a number of explicit response formulae around the boundary driven
zero range process to changes in the exit and entrance rates. In such a
nonequilibrium regime kinetic (and not only thermodynamic) aspects make a
difference in the response. Apart from a number of formal approaches, we
illustrate a general decomposition of the linear response into entropic and
frenetic contributions, the latter being realized from changes in the dynamical
activity at the boundaries. In particular, in this way one obtains nonlinear
modifications to the Green-Kubo relation. We end by bringing some general
remarks about the situation where that nonequilibrium response remains given by
the (equilibrium) Kubo formula such as for the density profile in the boundary
driven Lorentz gas.


title: Planar relative Schottky sets and quasisymmetric maps

abstract:
  A relative Schottky set in a planar domain D is a subset of D obtained by
removing from D open geometric discs whose closures are in D and are pairwise
disjoint. In this paper we study quasisymmetric and related maps between
relative Schottky sets of measure zero. We prove, in particular, that
quasisymmetric maps between such sets in Jordan domains are conformal, locally
bi-Lipschitz, and that their first derivatives are locally Lipschitz. We also
provide a locally bi-Lipschitz uniformization result for relative Schottky sets
in Jordan domains and establish rigidity with respect to local quasisymmetric
maps for relative Schottky sets in the unit disc.


title:
Gamma-ray blazars near equipartition and the origin of the GeV spectral
  break in 3C 454.3

abstract:
  Observations performed with the Fermi-LAT telescope have revealed the
presence of a spectral break in the GeV spectrum of flat-spectrum radio quasars
(FSRQs) and other low- and intermediate-synchrotron peaked blazars. We propose
that this feature can be explained by Compton scattering of broad-line region
(BLR) photons by a non-thermal population of electrons described by a
log-parabolic function. We consider in particular a scenario in which the
energy densities of particles, magnetic field, and soft photons in the emitting
region are close to equipartition. We show that this model can satisfactorily
account for the overall spectral energy distribution of the FSRQ 3C 454.3,
reproducing the GeV spectal cutoff due to Klein-Nishina effects and a curving
electron distribution.


title:
A generative spike train model with time-structured higher order
  correlations

abstract:
  Emerging technologies are revealing the spiking activity in ever larger
neural ensembles. Frequently, this spiking is far from independent, with
correlations in the spike times of different cells. Understanding how such
correlations impact the dynamics and function of neural ensembles remains an
important open problem. Here we describe a new, generative model for correlated
spike trains that can exhibit many of the features observed in data. Extending
prior work in mathematical finance, this generalized thinning and shift (GTaS)
model creates marginally Poisson spike trains with diverse temporal correlation
structures. We give several examples which highlight the model's flexibility
and utility. For instance, we use it to examine how a neural network responds
to highly structured patterns of inputs. We then show that the GTaS model is
analytically tractable, and derive cumulant densities of all orders in terms of
model parameters. The GTaS framework can therefore be an important tool in the
experimental and theoretical exploration of neural dynamics.


title: A Sierpi\'nski carpet with the co-Hopfian property

abstract:
  Motivated by questions in geometric group theory we define a quasisymmetric
co-Hopfian property for metric spaces and provide an example of a metric
Sierpi\'nski carpet with this property. As an application we obtain a
quasi-isometrically co-Hopfian Gromov hyperbolic space with a Sierpi\'nski
carpet boundary at infinity. In addition, we give a complete description of the
quasisymmetry group of the constructed Sierpi\'nski carpet. This group is
uncountable and coincides with the group of bi-Lipschitz transformations.


title:
Super-Resolving Quantum Radar: Coherent-State Sources with Homodyne
  Detection Suffice to Beat the Diffraction Limit

abstract:
  There has been much recent interest in quantum metrology for applications to
sub-Raleigh ranging and remote sensing such as in quantum radar. For quantum
radar, atmospheric absorption and diffraction rapidly degrades any actively
transmitted quantum states of light, such as N00N states, so that for this
high-loss regime the optimal strategy is to transmit coherent states of light,
which suffer no worse loss than the linear Beer's law for classical radar
attenuation, and which provide sensitivity at the shot-noise limit in the
returned power. We show that coherent radar radiation sources, coupled with a
quantum homodyne detection scheme, provide both longitudinal and angular
super-resolution much below the Rayleigh diffraction limit, with sensitivity at
shot-noise in terms of the detected photon power. Our approach provides a
template for the development of a complete super-resolving quantum radar system
with currently available technology.


title: Local Messages for Smartphones

abstract:
  This paper describes a new model for local messaging based on the network
proximity. We present a novelty mobile mashup which combines Wi-Fi proximity
measurements with Cloud Messaging. Our mobile mashup combines passive
monitoring for smart phones and cloud based messaging for mobile operational
systems. Passive monitoring can determine the location of mobile subscribers
(mobile phones, actually) without the active participation of mobile users.
This paper describes how to combine the passive monitoring and notifications.


title:
Possible realization of an antiferromagnetic Griffiths phase in
  Ba[Fe(1-x)Mn(x)](2)As(2)

abstract:
  We investigate magnetic ordering in metallic Ba[Fe(1-x)Mn(x)](2)As(2) and
discuss the unusual magnetic phase, which was recently discovered for Mn
concentrations x > 10%. We argue that it can be understood as a Griffiths-type
phase that forms above the quantum critical point associated with the
suppression of the stripe-antiferromagnetic spin-density-wave (SDW) order in
BaFe2As2 by the randomly introduced localized Mn moments acting as strong
magnetic impurities. While the SDW transition at x = 0, 2.5% and 5% remains
equally sharp, in the x = 12% sample we observe an abrupt smearing of the
antiferromagnetic transition in temperature and a considerable suppression of
the spin gap in the magnetic excitation spectrum. According to our
muon-spin-relaxation, nuclear magnetic resonance and neutron-scattering data,
antiferromagnetically ordered rare regions start forming in the x = 12% sample
significantly above the N\'eel temperature of the parent compound. Upon
cooling, their volume grows continuously, leading to an increase in the
magnetic Bragg intensity and to the gradual opening of a partial spin gap in
the magnetic excitation spectrum. Using neutron Larmor diffraction, we also
demonstrate that the magnetically ordered volume is characterized by a finite
orthorhombic distortion, which could not be resolved in previous diffraction
studies most probably due to its coexistence with the tetragonal phase and a
microstrain-induced broadening of the Bragg reflections. We argue that
Ba[Fe(1-x)Mn(x)](2)As(2) could represent an interesting model spin-glass
system, in which localized magnetic moments are randomly embedded into a SDW
metal with Fermi surface nesting.


title: The deformation complex is a homotopy invariant of a homotopy algebra

abstract:
  To a homotopy algebra one may associate its deformation complex, which is
naturally a differential graded Lie algebra. We show that infinity
quasi-isomorphic homotopy algebras have L-infinity quasi-isomorphic deformation
complexes by an explicit construction.


title:
Transmission photometry of WASP-12b: simultaneous measurement of the
  planetary radius in three bands

abstract:
  Transmission spectroscopy has been successfully used from both the ground and
in space to characterise the atmospheres of transiting exoplanets. This
technique is challenging from the ground because ground-based spectrographs
tend not to be designed to be photometrically stable, and effects such as
variable slit losses cause significant systematic uncertainties. An alternative
approach is to use simultaneous photometric observations in multiple wavebands
to determine wavelength dependent transit depth differences. We report an
application of this technique to one of the hottest known exoplanets, WASP-12b,
using the triple-beam camera ULTRACAM. We obtained simultaneous light curves in
Sloan u', and two narrow band filters centered on 4169 and 6010 angstroms, with
FWHMs 52 and 118 angstroms respectively. We fit these light curves with a
photometric model and determine the planetary radius in the three different
bands. Our data show no evidence for a difference in planetary radius over the
wavelength range we study, and are consistent with an atmosphere that is
dominated by Rayleigh scattering from a high altitude haze, as well as more
complicated atmosphere models which include the effects of molecules such as
TiO. Our planetary radius measurements have an average precision of 2.6 per
cent, compared to the ~1.4 - 2.4 per cent radius differences predicted by the
models over this wavelength range. We also find a consistent time of ingress
and egress across our three wavebands, in contrast to the early ingress which
has been reported for this system at shorter wavelengths.


title:
Homogenization of a generalized Stefan Problem in the context of ergodic
  algebras

abstract:
  We address the deterministic homogenization, in the general context of
ergodic algebras, of a doubly nonlinear problem which generalizes the well
known Stefan model, and includes the classical porous medium equation. It may
be represented by the differential inclusion, for a real-valued function
$u(x,t)$, $$
  \frac{\partial}{\partial t}\partial_u \Psi(x/\ve,x,u)-\nabla_x\cdot
\nabla_\eta\psi( x/\ve,x,t,u,\nabla u) \ni f(x/\ve,x,t, u), $$ on a bounded
domain $\Om\subset \R^n$, $t\in(0,T)$, together with initial-boundary
conditions, where $\Psi(z,x,\cdot)$ is strictly convex and
$\psi(z,x,t,u,\cdot)$ is a $C^1$ convex function, both with quadratic growth,
satisfying some additional technical hypotheses. As functions of the
oscillatory variable, $\Psi(\cdot,x,u),\psi(\cdot,x,t,u,\eta)$ and
$f(\cdot,x,t,u)$ belong to the generalized Besicovitch space $\BB^2$ associated
with an arbitrary ergodic algebra $\AA$. The periodic case was addressed by
Visintin (2007), based on the two-scale convergence technique. Visintin's
analysis for the periodic case relies heavily on the possibility of reducing
two-scale convergence to the usual $L^2$ convergence in the cartesian product
$\Pi\X\R^n$, where $\Pi$ is the periodic cell. This reduction is no longer
possible in the case of a general ergodic algebra. To overcome this difficulty,
we make essential use of the concept of two-scale Young measures for algebras
with mean value, associated with bounded sequences in $L^2$.


title: Flying Triangulation - towards the 3D movie camera

abstract:
  Flying Triangulation sensors enable a free-hand and motion-robust 3D data
acquisition of complex shaped objects. The measurement principle is based on a
multi-line light-sectioning approach and uses sophisticated algorithms for
real-time registration (S. Ettl et al., Appl. Opt. 51 (2012) 281-289). As
"single-shot principle", light sectioning enables the option to get surface
data from one single camera exposure. But there is a drawback: A pixel-dense
measurement is not possible because of fundamental information-theoretical
reasons. By "pixel-dense" we understand that each pixel displays individually
measured distance information, neither interpolated from its neighbour pixels
nor using lateral context information. Hence, for monomodal single-shot
principles, the 3D data generated from one 2D raw image display a significantly
lower space-bandwidth than the camera permits. This is the price one must pay
for motion robustness. Currently, our sensors project about 10 lines (each with
1000 pixels), reaching an considerable lower data efficiency than theoretically
possible for a single-shot sensor. Our aim is to push Flying Triangulation to
its information-theoretical limits. Therefore, the line density as well as the
measurement depth needs to be significantly increased. This causes serious
indexing ambiguities. On the road to a single-shot 3D movie camera, we are
working on solutions to overcome the problem of false line indexing by
utilizing yet unexploited information. We will present several approaches and
will discuss profound information-theoretical questions about the information
efficiency of 3D sensors.


title:
Spectral evolution of the SU(4) Kondo effect from the single impurity to
  the two-dimensional lattice

abstract:
  We describe the evolution of the SU(4) Kondo effect as the number of magnetic
centers increases from one impurity to the two-dimensional (2D) lattice. We
derive a Hubbard-Anderson model which describes a 2D array of atoms or
molecules with two-fold orbital degeneracy, acting as magnetic impurities and
interacting with a metallic host. We calculate the differential conductance,
observed typically in experiments of scanning tunneling spectroscopy, for
different arrangements of impurities on a metallic surface: a single impurity,
a periodic square lattice, and several sites of a rectangular cluster. Our
results point towards the crucial importance of the orbital degeneracy and
agree well with recent experiments in different systems of iron(II)
phtalocyanine molecules deposited on top of Au(111) [N. Tsukahara et al., Phys.
Rev. Lett. 106, 187201 (2011)], indicating that this would be the first
experimental realization of an artificial 2D SU(4) Kondo-lattice system.


title: Average Stretch Factor: How Low Does It Go?

abstract:
  In a geometric graph, $G$, the \emph{stretch factor} between two vertices,
$u$ and $w$, is the ratio between the Euclidean length of the shortest path
from $u$ to $w$ in $G$ and the Euclidean distance between $u$ and $w$. The
\emph{average stretch factor} of $G$ is the average stretch factor taken over
all pairs of vertices in $G$. We show that, for any constant dimension, $d$,
and any set, $V$, of $n$ points in $\mathbb{R}^d$, there exists a geometric
graph with vertex set $V$, that has $O(n)$ edges, and that has average stretch
factor $1+ o_n(1)$. More precisely, the average stretch factor of this graph is
$1+O((\log n/n)^{1/(2d+1)})$. We complement this upper-bound with a lower
bound: There exist $n$-point sets in $\mathbb{R}^2$ for which any graph with
$O(n)$ edges has average stretch factor $1+\Omega(1/\sqrt{n})$. Bounds of this
type are not possible for the more commonly studied worst-case stretch factor.
In particular, there exists point sets, $V$, such that any graph with
worst-case stretch factor $1+o_n(1)$ has a superlinear number of edges.


title:
The Continuity of $\mathbb{Q}_+$-Homogeneous Superadditive
  Correspondences

abstract:
  In this paper we investigate the continuity of $\mathbb{Q}_+$-homogeneous
superadditive correspondences defined on the cones with finite basis in real
topological vector spaces. It is also shown that every lower semicontinuous and
$\mathbb{Q}_+$-homogeneous superadditive correspondence between two cones with
finite basis admits a family of continuous linear selections.


title: Model Independent Framework for Searches of Top Partners

abstract:
  We propose a model-independent and general framework to study the LHC
phenomenology of top partners, i.e. Vector-Like quarks including particles with
different electro-magnetic charge. We consider Vector-Like quarks embedded in
general representations of the weak SU(2)L, coupling to all Standard Model
quarks via Yukawa mixing focusing on the case of a single multiplet. We show
that, with very minimal and quite general assumptions, top partners may be
studied in terms of few parameters in an effective Lagrangian description with
a clear and simple connection with experimental observables. We also
demonstrate that the parametrisation can be applied as well to cases with many
Vector-like multiplets, thus covering most realistic models of New Physics. We
perform a numerical study to understand the conclusions which can be drawn
within such a description and the expected potential for discovery or exclusion
at the LHC. Our main results are a clear connection between branching ratios
and single production channels, and the identification of novel interesting
channels to be studied at the LHC.


title: A Model for Stock Returns and Volatility

abstract:
  We prove that Student's t-distribution provides one of the better fits to
returns of S&P component stocks and the generalized inverse gamma distribution
best fits VIX and VXO volatility data. We further argue that a more accurate
measure of the volatility may be possible based on the fact that stock returns
can be understood as the product distribution of the volatility and normal
distributions. We find Brown noise in VIX and VXO time series and explain the
mean and the variance of the relaxation times on approach to the steady-state
distribution.


title: Solar-cycle related variation of solar differential rotation

abstract:
  Solar-cycle related variation of differential rotation is investigated
through analyzing the rotation rates of magnetic fields, distributed along
latitudes and varying with time at the time interval of August 1976 to April
2008. More pronounced differentiation of rotation rates is found to appear at
the ascending part of a Schwabe cycle than at the descending part on an
average. The coefficient $B$ in the standard form of differential rotation,
which represents the latitudinal gradient of rotation, may be divided into
three parts within a Schwabe cycle. Part one spans from the start to the
$4^{th}$ year of a Schwabe cycle, within which the absolute $B$ is
approximately a constant or slightly fluctuates. Part two spans from the
$4^{th}$ to the $7^{th}$ year, within which the absolute $B$ decreases. Part
three spans from the $7^{th}$ year to the end, within which the absolute $B$
increases. Strong magnetic fields repress differentiation of rotation rates, so
that rotation rates show less pronounced differentiation, but weak magnetic
fields seem to just reflect differentiation of rotation rates. The solar-cycle
related variation of solar differential rotation is inferred to the result of
both the latitudinal migration of the surface torsional pattern and the
repression of strong magnetic activity to differentiation of rotation rates.


title:
Effect of low-temperature annealing on the electronic- and
  band-structure of (Ga,Mn)As epitaxial layers

abstract:
  The effect of outdiffusion of Mn interstitials from (Ga,Mn)As epitaxial
layers, caused by post-growth low-temperature annealing, on their electronic-
and band-structure properties has been investigated by modulation
photoreflectance (PR) spectroscopy. The annealing-induced changes in structural
and magnetic properties of the layers were examined with high-resolution X-ray
diffractometry and SQUID magnetometery, respectively. They confirmed an
outdiffusion of Mn interstitials from the layers and an enhancement in their
hole concentration, which were more efficient for the layer covered with a Sb
cap acting as a sink for diffusing Mn interstitials. The PR results revealing a
decrease in the band-gap-transition energy in the as-grown (Ga,Mn)As layers,
with respect to that in the reference GaAs one, are interpreted by assuming a
merging of the Mn-related impurity band with the host GaAs valence band. On the
other hand, an increase in the band-gap-transition energy in the annealed
(Ga,Mn)As layers is interpreted as a result of the Moss-Burstein shift of the
absorption edge due to the Fermi level location within the valence band,
determined by the enhanced free-hole concentration. The experimental results
are consistent with the valence-band origin of mobile holes mediating
ferromagnetic ordering in (Ga,Mn)As, in agreement with the Zener model for
ferromagnetic semiconductors.


title:
Unveiling the corona of the Milky Way via ram-pressure stripping of
  dwarf satellites

abstract:
  The spatial segregation between dSphs and dIrrs in the Local Group has long
been regarded as evidence of an interaction with their host galaxies. In this
paper, we assume that ram-pressure stripping is the dominant mechanism that
removed gas from the dSphs and we use this to derive a lower bound on the
density of the corona of the Milky Way at large distances (50-90 kpc) from the
Galactic centre. At the same time, we derive an upper bound by demanding that
the interstellar medium of the dSphs is in pressure equilibrium with the hot
corona. We consider two dwarfs (Sextans and Carina) with well-determined orbits
and star formation histories. Our approach introduces several novel features:
we use the measured star formation histories of the dwarfs to derive the time
at which they last lost their gas, and (via a modified version of the
Kennicutt-Schmidt relation) their internal gas density at that time; we use a
large suite of 2D hydrodynamical simulations to model the gas stripping; and we
include supernova feedback tied to the gas content. Despite having very
different orbits and star formation histories, we find results for the two
dSphs that are in excellent agreement with one another. We derive an average
particle density of the corona of the Milky Way at 50-90 kpc in the range
1.3-3.6 10^{-4} cm^{-3}. Including additional constraints from X-ray emission
limits and pulsar dispersion measurements, we extrapolate Galactic coronal
density profiles and we estimate the fraction of baryons that can exist within
the virial radius of the Milky Way. For an isothermal corona (T=1.8 10^6 K)
this is small, 10-20 % of the universal baryon fraction. Only a hot (T=3 10^6
K) and adiabatic corona can contain all of the Galaxy's missing baryons. Models
for the Milky Way must explain why its corona is in a hot adiabatic thermal
state or why a large fraction of its baryons lie beyond the virial radius.


title: Re-examining the membership and origin of the Epsilon Cha association

abstract:
  We present a comprehensive investigation of the Epsilon Chamaeleontis
association (Epsilon Cha), one of several young moving groups spread across the
southern sky. We re-assess the putative membership of Epsilon Cha using the
best-available proper motion and spectroscopic measurements, including new ANU
2.3-m/WiFeS observations. After applying a kinematic analysis our final
membership comprises 35-41 stars from B9 to mid-M spectral types, with a mean
distance of 110+/-7 pc and a mean space motion of
(U,V,W)=(-10.9+/-0.8,-20.4+/-1.3,-9.9+/-1.4) km/s. Theoretical evolutionary
models suggest Epsilon Cha is 3-5 Myr old, distinguishing it as the youngest
moving group in the solar neighbourhood. Fifteen members show 3-22 micron
spectral energy distributions attributable to circumstellar discs, including 11
stars which appear to be actively accreting. Epsilon Cha's disc and accretion
fractions (29+8-6 and 32+9-7 per cent, respectively) are both consistent with a
typical 3-5 Myr-old population. Multi-epoch spectroscopy reveals three M-type
members with broad and highly-variable H-alpha emission as well as several new
spectroscopic binaries. We reject 11 stars proposed as members in the
literature and suggest they may belong to the background Cha I and II clouds or
other nearby young groups. Our analysis underscores the importance of a
holistic and conservative approach to assigning young stars to kinematic
groups, many of which have only subtly different properties and ill-defined
memberships. We conclude with a brief discussion of Epsilon Cha's connection to
the young open cluster Eta Cha and the Sco-Cen OB association. Contrary to
earlier studies which assumed Eta and Epsilon Cha are coeval and were born in
the same location, we find the groups were separated by ~30 pc when Eta Cha
formed 4-8 Myr ago in the outskirts of Sco-Cen, 1-3 Myr before the majority of
Epsilon Cha members.


title:
Swift-BAT hard X-ray sky monitoring unveils the orbital period of the
  HMXB IGR J18219-1347

abstract:
  IGR J18219-1347 is a hard X-ray source discovered by INTEGRAL in 2010. We
have analyzed the X-ray emission of this source exploiting the BAT survey data
up to March 2012 and the XRT data that include also an observing campaign
performed in early 2012. The source is detected at a significance level of ~14
standard deviations in the 88-month BAT survey data, and shows a strong
variability along the survey monitoring, going from high intensity to quiescent
states. A timing analysis on the BAT data revealed an intensity modulation with
a period of 72.46 days. The significance of this modulation is about 7 standard
deviations in Gaussian statistics. We interpret it as the orbital period of the
binary system. The light curve folded at P_0 shows a sharp peak covering ~30%
of the period, superimposed to a flat level roughly consistent with zero. In
the soft X-rays the source is detected only in 5 out of 12 XRT observations,
with the highest recorded count rate corresponding to a phase close to the BAT
folded light curve peak. The long orbital period and the evidence that the
source emits only during a small fraction of the orbit suggests that the IGR
J18219-1347 binary system hosts a Be star. The broad band XRT+BAT spectrum is
well modeled with a flat absorbed power law with a high energy exponential
cutoff at ~11 keV.


title:
Towards an unbiased determination of parton distributions with QED
  corrections

abstract:
  Electroweak corrections to hadron collider processes become relevant at the
level of precision reached by present-day LHC experiments. We provide a
preliminary discussion of the impact of electroweak corrections to parton
distributions, concentrating on electrodynamics corrections to parton evolution
equations, and showing a preliminary assessment of their impact. Furthermore,
we determine the parton distribution function of the photon from deep inelastic
scattering data using the NNPDF methodology.


title: Transits and Occultations of an Earth-Sized Planet in an 8.5-Hour Orbit

abstract:
  We report the discovery of an Earth-sized planet ($1.16\pm 0.19 R_\oplus$) in
an 8.5-hour orbit around a late G-type star (KIC 8435766, Kepler-78). The
object was identified in a search for short-period planets in the {\it Kepler}
database and confirmed to be a transiting planet (as opposed to an eclipsing
stellar system) through the absence of ellipsoidal light variations or
substantial radial-velocity variations. The unusually short orbital period and
the relative brightness of the host star ($m_{\rm Kep}$ = 11.5) enable robust
detections of the changing illumination of the visible hemisphere of the
planet, as well as the occultations of the planet by the star. We interpret
these signals as representing a combination of reflected and reprocessed light,
with the highest planet dayside temperature in the range of 2300 K to 3100 K.
Follow-up spectroscopy combined with finer sampling photometric observations
will further pin down the system parameters and may even yield the mass of the
planet.


title: Large N=4 Holography

abstract:
  The class of 2d minimal model CFTs with higher spin AdS3 duals is extended to
theories with large N=4 superconformal symmetry. We construct a higher spin
theory based on the global D(2,1|alpha) superalgebra, and propose a large N
family of cosets as a dual CFT description. We also indicate how a non-abelian
version of this Vasiliev higher spin theory might give an alternative
description of IIB string theory on an AdS3 x S3 x S3 x S1 background.


title: Dark Supersymmetry

abstract:
  We propose a model of Dark Supersymmetry, where a supersymmetric dark sector
is coupled to the classically scale invariant non-supersymmetric Standard Model
through the Higgs portal. The dark sector contains a mass scale that is
protected against radiative corrections by supersymmetry, and the portal
coupling mediates this scale to the Standard Model, resulting in a vacuum
expectation value for the Higgs field and the usual electroweak symmetry
breaking mechanism. The supersymmetric dark sector contains dark matter
candidates, and we show that the observed dark matter abundance is generated
for a natural choice of parameters, while avoiding the current experimental
bounds on direct detection. Future experiments can probe this scenario if the
dark sector mass scale is not too high.


title:
Swift Observations of the High-mass X-ray Binary IGR J16283-4838 unveil
  a 288-day Orbital Period

abstract:
  We report on the temporal and spectral properties of the HMXB IGR J16283-4838
in the hard X-ray band. We searched the first 88 months of Swift BAT survey
data for long-term periodic modulations. We also investigated the broad band
(0.2--150 keV) spectral properties of IGR J16283--4838 complementing the BAT
dataset with the soft X-ray data from the available Swift-XRT pointed
observations. The BAT light curve of IGR J16283-4838 revealed a periodic
modulation at P_o=287.6+7-1.7 days (with a significance higher than 4 standard
deviations). The profile of the light curve folded at P_o shows a sharp peak
lasting ~ 12 d, over a flat plateau. The long-term light curve shows also a
~300 d interval of prolonged enhanced emission. The observed phenomenology is
suggestive of a Be nature of IGR J16283-4838, where the narrow periodic peaks
and the ~300 d outburst can be interpreted as Type I and Type II outbursts,
respectively. The broad band 0.2-150 keV spectrum can be described with an
absorbed power-law and a steepening in the BAT energy range.


title:
Searching for Cooling Signatures in Strong Lensing Galaxy Clusters:
  Evidence Against Baryons Shaping the Matter Distribution in Cluster Cores

abstract:
  The process by which the mass density profile of certain galaxy clusters
becomes centrally concentrated enough to produce high strong lensing (SL)
cross-sections is not well understood. It has been suggested that the baryonic
condensation of the intra-cluster medium (ICM) due to cooling may drag dark
matter to the cores and thus steepen the profile. In this work, we search for
evidence of ongoing ICM cooling in the first large, well-defined sample of
strong lensing selected galaxy clusters in the range 0.1 < z < 0.6. Based on
known correlations between the ICM cooling rate and both optical emission line
luminosity and star formation, we measure, for a sample of 89 strong lensing
clusters, the fraction of clusters that have [OII]3727 emission in their
brightest cluster galaxy (BCG). We find that the fraction of line-emitting BCGs
is constant as a function of redshift for z > 0.2 and shows no statistically
significant deviation from the total cluster population. Specific star
formation rates, as traced by the strength of the 4000 angstrom break, D_4000,
are also consistent with the general cluster population. Finally, we use
optical imaging of the SL clusters to measure the angular separation, R_arc,
between the arc and the center of mass of each lensing cluster in our sample
and test for evidence of changing [OII] emission and D_4000 as a function of
R_arc, a proxy observable for SL cross-sections. D_4000 is constant with all
values of R_arc, and the [OII] emission fractions show no dependence on R_arc
for R_arc > 10" and only very marginal evidence of increased weak [OII]
emission for systems with R_arc < 10". These results argue against the ability
of baryonic cooling associated with cool core activity in the cores of galaxy
clusters to strongly modify the underlying dark matter potential, leading to an
increase in strong lensing cross-sections.


title:
Dynamical clustering and phase separation in suspensions of
  self-propelled colloidal particles

abstract:
  We study experimentally and numerically a (quasi) two dimensional colloidal
suspension of self-propelled spherical particles. The particles are
carbon-coated Janus particles, which are propelled due to diffusiophoresis in a
near-critical water-lutidine mixture. At low densities, we find that the
driving stabilizes small clusters. At higher densities, the suspension
undergoes a phase separation into large clusters and a dilute gas phase. The
same qualitative behavior is observed in simulations of a minimal model for
repulsive self-propelled particles lacking any alignment interactions. The
observed behavior is rationalized in terms of a dynamical instability due to
the self-trapping of self-propelled particles.


title:
Some combinatorial principles for trees and applications to
  tree-families in Banach spaces

abstract:
  Suppose that $(x_s)_{s\in S}$ is a normalized family in a Banach space
indexed by the dyadic tree $S$. Using Stern's combinatorial theorem we extend
important results from sequences in Banach spaces to tree-families. More
precisely, assuming that for any infinite chain $\beta$ of $S$ the sequence
$(x_s)_{s\in\beta}$ is weakly null, we prove that there exists a subtree $T$ of
$S$ such that for any infinite chain $\beta$ of $T$ the sequence
$(x_s)_{s\in\beta}$ is nearly (resp., convexly) unconditional. In the case
where $(f_s)_{s\in S}$ is a family of continuous functions, under some
additional assumptions, we prove the existence of a subtree $T$ of $S$ such
that for any infinite chain $\beta$ of $T$, the sequence $(f_s)_{s\in\beta}$ is
unconditional. Finally, in the more general setting where for any chain
$\beta$, $(x_s)_{s\in\beta}$ is a Schauder basic sequence, we obtain a
dichotomy result concerning the semi-boundedly completeness of the sequences
$(x_s)_{s\in\beta}$.


title: Correlations between Majorana fermions through a superconductor

abstract:
  We consider a model of ballistic quasi-one dimensional semiconducting wire
with intrinsic spin-orbit interaction placed on the surface of a bulk s-wave
superconductor (SC), in the presence of an external magnetic field. This setup
has been shown to give rise to a topological superconducting state in the wire,
characterized by a pair of Majorana-fermion (MF) bound states formed at the two
ends of the wire. Here we demonstrate that, besides the well-known direct
overlap-induced energy splitting, the two MF bound states may hybridize via
elastic correlated tunneling processes through virtual quasiparticles states in
the SC, giving rise to an additional energy splitting between MF states from
the same as well as from different wires.


title: On the U_p-operator in characteristic p

abstract:
  For a perfect field \kappa of characteristic p>0, a positive ingeger N not
divisible by p, and an arbitrary subgroup \Gamma of GL_2(Z/NZ), we prove (with
mild additional hypotheses when p\le 3) that the U-operator on the space
M_k(\Gamma/\kappa) of (Katz) modular forms for \Gamma over \kappa induces a
surjection U:M_{k}(\Gamma/\kappa)\rightarrow M_{k'}(\Gamma/\kappa) for all k\ge
p+2, where k'=(k-k_0)/p + k_0 with 2\le k_0\le p+1 the unique integer congruent
to k modulo p. When \kappa=F_p, p\ge 5, N\neq 2,3, and \Gamma is the subgroup
of upper-triangular or upper-triangular unipotent matrices, this recovers a
recent result of Dewar.


title: OscSNS: A Precision Neutrino Oscillation Experiment at the SNS

abstract:
  The growing evidence for short-baseline neutrino oscillations and the
possible existence of sterile neutrinos necessitates the development of a
cost-effective experiment that can resolve these mysteries. The OscSNS \cite{1}
experiment, located at the Spallation Neutron Source (SNS), Oak Ridge
Laboratory, is ideal for this purpose.


title: The Theory of Parity Violation in Few-Nucleon Systems

abstract:
  We review recent progress in the theoretical description of hadronic parity
violation in few-nucleon systems. After introducing the different methods that
have been used to study parity-violating observables we discuss the available
calculations for reactions with up to five nucleons. Particular emphasis is put
on effective field theory calculations where they exist, but earlier and
complementary approaches are also presented. We hope this review will serve as
a guide for those who wish to know what calculations are available and what
further calculations need to be completed before we can claim to have a
comprehensive picture of parity violation in few nucleon systems.


title: Dynamically Disordered Quantum Walk as a Maximal Entanglement Generator

abstract:
  We show that the entanglement between the internal (spin) and external
(position) degrees of freedom of a qubit in a random (dynamically disordered)
one-dimensional discrete time quantum random walk (QRW) achieves its maximal
possible value asymptotically in the number of steps, outperforming the
entanglement attained by using ordered QRW. The disorder is modeled by
introducing an extra random aspect to QRW, a classical coin that randomly
dictates which quantum coin drives the system's time evolution. We also show
that maximal entanglement is achieved independently of the initial state of the
walker, study the number of steps the system must move to be within a small
fixed neighborhood of its asymptotic limit, and propose two experiments where
these ideas can be tested.


title:
Measurement of the high-mass Drell--Yan differential cross-section in pp
  collisions at sqrt(s)=7 TeV with the ATLAS detector

abstract:
  This Letter reports a measurement of the high-mass Drell-Yan differential
cross-section in proton-proton collisions at a centre-of-mass energy of 7 TeV
at the LHC. Based on an integrated luminosity of 4.9 /fb, the differential
cross-section in the Z/gamma* to e+e- channel is measured with the ATLAS
detector as a function of the invariant mass, Mee, in the range 116 < Mee <
1500 GeV, for a fiducial region in which both the electron and the positron
have transverse momentum pT > 25 GeV and pseudorapidity eta < 2.5. A comparison
is made to various event generators and to the predictions of perturbative QCD
calculations at next-to-next-to-leading order.


title: Entanglement Structure in Expanding Universes

abstract:
  We investigate entanglement of a quantum field in de Sitter spacetime using a
particle detector model. By considering the entanglement between two comoving
detectors interacting with a scalar field, it is possible to detect the
entanglement of the scalar field by swapping it to detectors. For the massless
minimal scalar field, we find that the entanglement between the detectors
cannot be detected when their physical separation exceeds the Hubble horizon
scale. This behavior supports the appearance of the classical nature of quantum
fluctuations generated during the inflationary era.


title: PySLHA: a Pythonic interface to SUSY Les Houches Accord data

abstract:
  This paper describes the PySLHA package, a Python language module and program
collection for reading, writing and visualising SUSY model data in the SLHA
format. PySLHA can read and write SLHA data in a very general way, including
the official SLHA2 extension and user customisations, and with arbitrarily deep
indexing of data block entries and a dedicated, intuitive interface for
particle data and decay information. PySLHA can additionally read and write the
legacy ISAWIG model format, and provides format conversion scripts. The draft
SLHA3 XSECTION feature is also fully supported. A publication-quality mass
spectrum & decay chain plotting tool, slhaplot, is also included.


title: Search and Result Presentation in Scientific Workflow Repositories

abstract:
  We study the problem of searching a repository of complex hierarchical
workflows whose component modules, both composite and atomic, have been
annotated with keywords. Since keyword search does not use the graph structure
of a workflow, we develop a model of workflows using context-free bag grammars.
We then give efficient polynomial-time algorithms that, given a workflow and a
keyword query, determine whether some execution of the workflow matches the
query. Based on these algorithms we develop a search and ranking solution that
efficiently retrieves the top-k grammars from a repository. Finally, we propose
a novel result presentation method for grammars matching a keyword query, based
on representative parse-trees. The effectiveness of our approach is validated
through an extensive experimental evaluation.


title:
Efficient Parallelization of Short-Range Molecular Dynamics Simulations
  on Many-Core Systems

abstract:
  This article introduces a highly parallel algorithm for molecular dynamics
simulations with short-range forces on single node multi- and many-core
systems. The algorithm is designed to achieve high parallel speedups for
strongly inhomogeneous systems like nanodevices or nanostructured materials. In
the proposed scheme the calculation of the forces and the generation of
neighbor lists is divided into small tasks. The tasks are then executed by a
thread pool according to a dependent task schedule. This schedule is
constructed in such a way that a particle is never accessed by two threads at
the same time.Benchmark simulations on a typical 12 core machine show that the
described algorithm achieves excellent parallel efficiencies above 80 % for
different kinds of systems and all numbers of cores. For inhomogeneous systems
the speedups are strongly superior to those obtained with spatial
decomposition. Further benchmarks were performed on an Intel Xeon Phi
coprocessor. These simulations demonstrate that the algorithm scales well to
large numbers of cores.


title:
Quantum Path Interference through Incoherent Motions in Multilevel
  Quantum Systems

abstract:
  Quantum path interferences or resonances in multilevel dissipative quantum
systems play an important and intriguing role in the transport processes of
nanoscale systems. Many previous minimalistic models used to describe the
quantum path interference driven by incoherent fields are based on the
approximations including the second order perturbation for the weak coupling
limit, the ad-hoc choices of two-time correlation functions and $\it{etc}$. On
the other hand, the similar model to study the non-adiabatic molecular
electronic excitation have been extensively developed and many efficient
quantum molecular dynamics simulation schemes, such as the Ehrenfest scheme,
have been proposed.
  In this paper, I aim to propose an unified model, extend the Ehrenfest scheme
to study the interactions of system-light and system-phonon simultaneously and
gain insight into and principles of the roles of quantum path interferences in
the realistic molecular systems. I discuss how to derive the time-dependent
stochastic Schr$\ddot{o}$dinger equation from the Ehrenfest scheme as a
foundation to discuss the detailed balance for the weak coupling limit and
therefore the quantum correction in the Ehrenfest scheme. Different from the
master equation technique, the Ehrenfest scheme doesn't need any specific
assumptions about spectral densities and two time correlation functions. With
simple open two-level and three-level quantum systems, I show the effect of the
quantum path interference on the steady state populations. Currently I only
focus on the role of the phonon thermal reservoir. The electromagnetic field
(solar light) will be modeled as a thermal reservoir and discussed in detail in
the future paper.


title: The Large Observatory For X-ray Timing: LOFT

abstract:
  LOFT, the Large Observatory for X-ray Timing, is a new space mission concept
devoted to observations of Galactic and extra-Galactic sources in the X-ray
domain with the main goals of probing gravity theory in the very strong field
environment of black holes and other compact objects, and investigating the
state of matter at supra-nuclear densities in neutron stars. The instruments
on-board LOFT, the Large area detector and the Wide Field Monitor combine for
the first time an unprecedented large effective area (~10 m2 at 8 keV)
sensitive to X-ray photons mainly in the 2-30 keV energy range and a spectral
resolution approaching that of CCD-based telescopes (down to 200 eV at 6 keV).
LOFT is currently competing for a launch of opportunity in 2022 together with
the other M3 mission candidates of the ESA Cosmic Vision Program.


title:
Quickest Change Point Detection and Identification Across a Generic
  Sensor Array

abstract:
  In this paper, we consider the problem of quickest change point detection and
identification over a linear array of $N$ sensors, where the change pattern
could first reach any of these sensors, and then propagate to the other
sensors. Our goal is not only to detect the presence of such a change as
quickly as possible, but also to identify which sensor that the change pattern
first reaches. We jointly design two decision rules: a stopping rule, which
determines when we should stop sampling and claim a change occurred, and a
terminal decision rule, which decides which sensor that the change pattern
reaches first, with the objective to strike a balance among the detection
delay, the false alarm probability, and the false identification probability.
We show that this problem can be converted to a Markov optimal stopping time
problem, from which some technical tools could be borrowed. Furthermore, to
avoid the high implementation complexity issue of the optimal rules, we develop
a scheme with a much simpler structure and certain performance guarantee.


title: Diffuse $\gamma$-ray emission from misaligned active galactic nuclei

abstract:
  We calculate the diffuse $\gamma$-ray emission due to the population of
misaligned AGN (MAGN) unresolved by the Large Area Telescope (LAT) on the {\it
Fermi} Gamma-ray Space Telescope ({\it Fermi}). A correlation between the
$\gamma$-ray luminosity and the radio-core luminosity is established and
demonstrated to be physical by statistical tests, as well as compatible with
upper limits based on {\it Fermi}-LAT data for a large sample of radio-loud
MAGN. We constrain the derived $\gamma$-ray luminosity function by means of the
source count distribution of the MAGN detected by the {\it Fermi}-LAT. We
finally estimate the diffuse $\gamma$-ray flux due to the whole MAGN population
which ranges from 10% up to nearly the entire measured Isotropic Gamma-Ray
Background (IGRB). We evaluate also the room left to galactic DM at high
latitudes ($>10^\circ$), by taking into account the results on the MAGN
together with the other significant galactic and extragalactic $\gamma$-rays
emitting sources.


title:
Homodyne detection as a near-optimum receiver for phase-shift keyed
  binary communication in the presence of phase diffusion

abstract:
  We address binary optical communication channels based on phase-shift keyed
coherent signals in the presence of phase diffusion. We prove theoretically and
demonstrate experimentally that a discrimination strategy based on homodyne
detection is robust against this kind of noise for any value of the channel
energy. Moreover, we find that homodyne receiver beats the performance of
Kennedy receiver as the signal energy increases, and achieves the Helstrom
bound in the limit of large noise.


title:
Electroweak Sudakov effects in W, Z and gamma production at large
  transverse momentum

abstract:
  We study electroweak Sudakov effects in single W, Z and gamma production at
large transverse momentum using Soft Collinear Effective Theory. We present a
factorized form of the cross section near the partonic threshold with both QCD
and electroweak effects included and compute the electroweak corrections
arising at different scales. We analyze their size relative to the QCD
corrections as well as the impact of strong-electroweak mixing terms. Numerical
results for the vector-boson cross sections at the Large Hadron Collider are
presented.


title:
Luminosities of Carbon-rich Asymptotic Giant Branch stars in the Milky
  Way

abstract:
  Stars evolving along the Asymptotic Giant Branch can become Carbon-rich in
the final part of their evolution. They replenish the inter-stellar medium with
nuclear processed material via strong radiative stellar winds. The
determination of the luminosity function of these stars, even if far from being
conclusive, is extremely important to test the reliability of theoretical
models. In particular, strong constraints on the mixing treatment and the
mass-loss rate can be derived.
  We present an updated Luminosity Function of Galactic Carbon Stars obtained
from a re-analysis of available data already published in previous papers.
Starting from available near- and mid-infrared photometric data, we
re-determine the selection criteria. Moreover, we take advantage from updated
distance estimates and Period-Luminosity relations and we adopt a new
formulation for the computation of Bolometric Corrections. This leads us to
collect an improved sample of carbon-rich sources from which we construct an
updated Luminosity Function.
  The Luminosity Function of Galactic Carbon Stars peaks at magnitudes around
-4.9, confirming the results obtained in a previous work. Nevertheless, the
Luminosity Function presents two symmetrical tails instead of the larger high
luminosity tail characterizing the former Luminosity Function. The derived
Luminosity Function of Galactic Carbon Stars matches the indications coming
from recent theoretical evolutionary Asymptotic Giant Branch models, thus
confirming the validity of the choices of mixing treatment and mass-loss
history. Moreover, we compare our new Luminosity Function with its counterpart
in the Large Magellanic Cloud finding that the two distributions are very
similar for dust-enshrouded sources, as expected from stellar evolutionary
models. Finally, we derive a new fitting formula aimed to better determine
Bolometric Corrections for C-stars.


title: Machine learning on images using a string-distance

abstract:
  We present a new method for image feature-extraction which is based on
representing an image by a finite-dimensional vector of distances that measure
how different the image is from a set of image prototypes. We use the recently
introduced Universal Image Distance (UID) \cite{RatsabyChesterIEEE2012} to
compare the similarity between an image and a prototype image. The advantage in
using the UID is the fact that no domain knowledge nor any image analysis need
to be done. Each image is represented by a finite dimensional feature vector
whose components are the UID values between the image and a finite set of image
prototypes from each of the feature categories. The method is automatic since
once the user selects the prototype images, the feature vectors are
automatically calculated without the need to do any image analysis. The
prototype images can be of different size, in particular, different than the
image size. Based on a collection of such cases any supervised or unsupervised
learning algorithm can be used to train and produce an image classifier or
image cluster analysis. In this paper we present the image feature-extraction
method and use it on several supervised and unsupervised learning experiments
for satellite image data.


title: Quantum Computation with Magnetic Clusters

abstract:
  We propose a complete, quantitative quantum computing system which satisfies
the five DiVincenzo criteria. The model is based on magnetic clusters with
uniaxial anisotropy, where standard, two-state qubits are formed utilizing the
two lowest-lying states of an anisotropic potential energy. We outline the
quantum dynamics required by quantum computing for single qubit structures, and
then define a novel measurement scheme in which qubit sates can be measured by
sharp changes in current as voltage across the cluster is varied. We then
extend the single qubit description to multiple qubit interactions, facilitated
specifically by a new entanglement method which propagates the controlled-NOT
(C-NOT) quantum gate.


title:
The rise and fall of the Phytophthora infestans lineage that triggered
  the Irish potato famine

abstract:
  Phytophthora infestans, the cause of potato late blight, is infamous for
having triggered the Irish Great Famine in the 1840s. Until the late 1970s, P.
infestans diversity outside of its Mexican center of origin was low, and one
scenario held that a single strain, US-1, had dominated the global population
for 150 years; this was later challenged based on DNA analysis of historical
herbarium specimens. We have compared the genomes of 11 herbarium and 15 modern
strains. We conclude that the nineteenth century epidemic was caused by a
unique genotype, HERB-1, that persisted for over 50 years. HERB-1 is distinct
from all examined modern strains, but it is a close relative of US-1, which
replaced it outside of Mexico in the twentieth century. We propose that HERB-1
and US-1 emerged from a metapopulation that was established in the early 1800s
outside of the species' center of diversity.


title:
Speeding Up Classical and Quantum Adiabatic Processes: Implications for
  Work Functions and Heat Engine Designs

abstract:
  Adiabatic processes are important for studying the dynamics of a
time-dependent system. Conventionally, the adiabatic processes can only be
achieved by varying the system slowly. We speed up both classical and quantum
adiabatic processes by adding control protocols. In classical systems, we work
out the control protocols by analyzing the classical adiabatic approximation.
In quantum systems, we follow the idea of transitionless driving by Berry [J.
Phys. A: Math. Theor. Vol.42 365303 (2009)]. Such fast-forward adiabatic
processes can be performed at arbitrary fast speed, and in the meanwhile reduce
the work fluctuation. In both systems, we use a time-dependent harmonic
oscillator model to work out explicitly the work function and the work
fluctuation in three types of processes: fast-forward adiabatic processes,
adiabatic processes, and non-adiabatic processes. We show the significant
reduction on work fluctuation in fast-forward adiabatic process. We further
illustrate how the fast-forward process improved the converging rate of the
Jarzynski equality between the work function and the free energy. As an
application, we show that the fast-forward process not only maximizes the
output power but also improve the efficiency of a quantum engine.


title:
Relation between masses of particles and the Fermi constant in the
  electroweak Standard Model

abstract:
  An empirical formula relating the physical masses of elementary particles and
the Fermi constant is proposed. Although no mechanism or theoretical model
behind this formula is advocated, we seek for a possible physical
interpretation. If not a simple numerical coincidence, this formula may
motivate theorists to search for relations among the different sectors of the
Electroweak Standard model.


title:
Dense spectrum of resonances and spin-1/2 particle capture in a
  near-black-hole metric

abstract:
  We show that a spin-1/2 particle in the gravitational field of a massive body
of radius R which slightly exceeds the Schwarzschild radius r_s, possesses a
dense spectrum of narrow resonances. Their lifetimes and density tend to
infinity in the limit R -> r_s. We determine the cross section of the particle
capture into these resonances and show that it is equal to the spin-1/2
absorption cross section for a Schwarzschild black hole. Thus black-hole
properties may emerge in a non-singular static metric prior to the formation of
a black hole.


title: Mobile Network Anomaly Detection and Mitigation: The NEMESYS Approach

abstract:
  Mobile malware and mobile network attacks are becoming a significant threat
that accompanies the increasing popularity of smart phones and tablets. Thus in
this paper we present our research vision that aims to develop a network-based
security solution combining analytical modelling, simulation and learning,
together with billing and control-plane data, to detect anomalies and attacks,
and eliminate or mitigate their effects, as part of the EU FP7 NEMESYS project.
These ideas are supplemented with a careful review of the state-of-the-art
regarding anomaly detection techniques that mobile network operators may use to
protect their infrastructure and secure users against malware.


title: Weak and Extended H2 Emission in NGC 6369

abstract:
  NGC 6369 is a double-shell PN with a filamentary outer shell or envelope and
faint bipolar extensions. We have used ground- and space-based narrowband
optical and near-IR images, broadband mid-IR images, optical long-slit echelle
spectra, and mid-IR spectra to investigate its physical structure. The
observations confirm a bipolar structure for the inner shell of NGC 6369, but
they also reveal evidence for H2 and strong polycyclic aromatic hydrocarbons
(PAHs) emission from a photo-dissociation region (PDR) with molecular
inclusions located outside the bright inner shell.


title: Experimental Distillation of Quantum Nonlocality

abstract:
  We report the first experimental demonstration of distillation of quantum
nonlocality, confirming the recent theoretical protocol [\textit{Phys. Rev.
Lett. 102, 120401 (2009)}]. Quantum nonlocality is described by a correlation
box with binary inputs and outputs, and the nonlocal boxes are realized through
appropriate measurements on polarization entangled photon pairs. We demonstrate
that nonlocality is amplified by connecting two nonlocal boxes into a composite
one through local operations and four-photon coincidence measurements.


title:
Neutrino signals from ultracompact minihalos and constraints on the
  primordial curvature perturbation

abstract:
  Compared with that of standard dark matter halos, the density profile of the
recently proposed new kind of dark matter structure named ultracompact
minihalos (UCMHs) is steeper and its formation time is earlier. If the dark
matter is composed of weakly interactive massive particles (WIMP), the
potential signals, e.g. neutrinos, from UCMHs due to the dark matter
annihilation would be detected by IceCube/DeepCore or other detectors and such
signals would have a very useful complementarity of gamma rays observations. On
the other hand, the formation of UCMHs is related to primordial curvature
perturbations on the smaller scales. So constraints on the abundance of UCMHs
can be used to give a limit on the perturbations on these scales. In previous
works in the literature, the authors focused on the {\gamma}-ray signals from
UCMHs due to dark matter annihilation. In this work, we investigate the
neutrino signals from nearby UCMHs. Although no excess of neutrino signals the
dark matter annihilation has been observed, the constraints on the abundance of
UCMHs can be obtained and these constraints can be translated into the limit on
the primordial curvature perturbations on small scales.


title: Rapidly growing entire functions with three singular values

abstract:
  We settle the problem of finding an entire function with three singular
values whose Nevanlinna characteristic dominates an arbitrarily prescribed
function.


title: Homomorphims from the fundamental group of planar sets

abstract:
  We prove that every homomorphism from the fundamental group of a planar Peano
continuum to the fundamental group of a planar or one-dimensional Peano
continuum is induced by a continuous map up to conjugation.
  This is then used to provide a family of uncountable many planar Peano
continua with pairwise non-isomorphic fundamental groups all of which are not
homotopy equivalent to a one-dimensional space.


title:
Simpsonian 'Evolution by Jumps' in an Adaptive Radiation of Anolis
  Lizards

abstract:
  In his highly influential view of evolution, G. G. Simpson hypothesized that
clades of species evolve in adaptive zones, defined as collections of niches
occupied by species with similar traits and patterns of habitat use. Simpson
hypothesized that species enter new adaptive zones in one of three ways:
extinction of competitor species, dispersal to a new geographic region, or the
evolution of a key trait that allows species to exploit resources in a new way.
However, direct tests of Simpson's hypotheses for the entry into new adaptive
zones remain elusive. Here we evaluate the fit of a Simpsonian model of jumps
between adaptive zones to phylogenetic comparative data. We use a novel
statistical approach to show that anoles, a well-studied adaptive radiation of
Caribbean lizards, have evolved by a series of evolutionary jumps in trait
evolution. Furthermore, as Simpson predicted, trait axes strongly tied to
habitat specialization show jumps that correspond with the evolution of key
traits and/or dispersal between islands in the Greater Antilles. We conclude
that jumps are commonly associated with major adaptive shifts in the
evolutionary radiation of anoles.


title: On the Cauchy transform of weighted Bergman spaces

abstract:
  The problem of describing the range of a Bergman space B_2(G) under the
Cauchy transform K for a Jordan domain G was solved by Napalkov (Jr) and
Yulmukhametov. It turned out that K(B_2(G))=B_2^1(C\bar G) if and only if G is
a quasidisk; here B_2^1(C\bar G) is the Dirichlet space of the complement of
\bar G. The description of K(B_2(G)) for an integrable Jordan domain is given
in [S. Merenkov, "On the Cauchy transform of the Bergman space", Mat. Fiz.
Anal. Geom., 7 (2000), no. 1, 119-127]. In the present paper we give a
description of K(B_2(G,\omega)) analogous to the one given in [S. Merenkov, "On
the Cauchy transform of the Bergman space", Mat. Fiz. Anal. Geom., 7 (2000),
no. 1, 119-127] for a weighted Bergman space B_2(G,\omega) with a weight
\omega\ which is constant on level lines of the Green function of G. In the
case G=D, the unit disk, and under some additional conditions on the weight
\omega, K(B_2(D,\omega))=B_2^1(C\bar{D}, \omega^{-1}), a weighted analogue of a
Dirichlet space.


title:
Study of the $K^+ K^-$ invariant-mass dependence of CP asymmetry in $B^+
  \rightarrow K^+ K^- K^+$ decays

abstract:
  As a followup to the latest BABAR amplitude analysis of the decay $B^+
\rightarrow K^+ K^- K^+$, we investigate the $K^+ K^-$ invariant-mass
dependence of the CP asymmetry and compare it to that obtained by the LHCb
collaboration. The results are based on a data sample of approximately $470
\times 10^6 B\bar{B}$ decays, collected with the BABAR detector at the PEP-II
asymmetric-energy $B$ factory at the SLAC National Accelerator Laboratory.


title: Spectrum Sharing for Device-to-Device Communication in Cellular Networks

abstract:
  This paper addresses two fundamental and interrelated issues in
device-to-device (D2D) enhanced cellular networks. The first issue is how D2D
users should access spectrum, and we consider two choices: overlay (orthogonal
spectrum between D2D and cellular UEs) and underlay (non-orthogonal). The
second issue is how D2D users should choose between communicating directly or
via the base station, a choice that depends on distance between the potential
D2D transmitter and receiver. We propose a tractable hybrid network model where
the positions of mobiles are modeled by random spatial Poisson point process,
with which we present a general analytical approach that allows a unified
performance evaluation for these questions. Then, we derive analytical rate
expressions and apply them to optimize the two D2D spectrum sharing scenarios
under a weighted proportional fair utility function. We find that as the
proportion of potential D2D mobiles increases, the optimal spectrum partition
in the overlay is almost invariant (when D2D mode selection threshold is large)
while the optimal spectrum access factor in the underlay decreases. Further,
from a coverage perspective, we reveal a tradeoff between the spectrum access
factor and the D2D mode selection threshold in the underlay: as more D2D links
are allowed (due to a more relaxed mode selection threshold), the network
should actually make less spectrum available to them to limit their
interference.


title: Building a Hydrodynamics Code with Kinetic Theory

abstract:
  We report on the development of a test-particle based kinetic Monte Carlo
code for large systems and its application to simulate matter in the continuum
regime. Our code combines advantages of the Direct Simulation Monte Carlo and
the Point-of-Closest-Approach methods to solve the collision integral of the
Boltzmann equation. With that, we achieve a high spatial accuracy in
simulations while maintaining computational feasibility when applying a large
number of test-particles. The hybrid setup of our approach allows us to study
systems which move in and out of the hydrodynamic regime, with low and high
particle densities. To demonstrate our code's ability to reproduce hydrodynamic
behavior we perform shock wave simulations and focus here on the Sedov blast
wave test. The blast wave problem describes the evolution of a spherical
expanding shock front and is an important verification problem for codes which
are applied in astrophysical simulation, especially for approaches which aim to
study core-collapse supernovae.


title:
Spin force and the generation of sustained spin current in
  time-dependent Rashba and Dresselhauss systems

abstract:
  The generation of spin current and spin polarization in a 2DEG structure is
studied in the presence of Dresselhaus and Rashba spin-orbit couplings (SOC),
the strength of the latter being modulated in time by an ac gate voltage. By
means of the non-Abelian gauge field approach, we established the relation
between the Lorentz spin force and the spin current in the SOC system, and
showed that the longitudinal component of the spin force induces a transverse
spin current. For a constant (time-invariant) Rashba system, we recover the
universal spin Hall conductivity of $\frac e{8\pi}$, derived previously via the
Berry phase and semiclassical methods. In the case of a time-dependent SOC
system, the spin current is sustained even under strong impurity scattering. We
evaluated the ac spin current generated by a time-modulated Rashba SOC in the
absence of any dc electric field. The magnitude of the spin current reaches a
maximum when the modulation frequency matches the Larmor frequency of the
electrons.


title:
On the mathematically reliable long-term simulation of chaos of Lorenz
  equation in the interval [0,10000]

abstract:
  Using 1200 CPUs of the National Supercomputer TH-A1 and a parallel integral
algorithm based on the 3500th-order Taylor expansion and the 4180-digit
multiple precision data, we have done a reliable simulation of chaotic solution
of Lorenz equation in a rather long interval [0,10000] (Lorenz time unit). Such
a kind of mathematically reliable chaotic simulation has never been reported.
It provides us a numerical benchmark for mathematically reliable long-term
prediction of chaos. Besides, it also proposes a safe method for mathematically
reliable simulations of chaos in a finite but long enough interval. In
addition, our very fine simulations suggest that such a kind of mathematically
reliable long-term prediction of chaotic solution might have no physical
meanings, because the inherent physical micro-level uncertainty due to thermal
fluctuation might quickly transfer into macroscopic uncertainty so that
trajectories for a long enough time would be essentially uncertain in physics.


title: The $a$-theorem and temperature of the CMB temperature in cosmology

abstract:
  Initial conditions in cosmology in the form of the microcanonical density
matrix of the Universe predict a thermal nature of the primordial CMB power
spectrum with a nonzero temperature of the resulting relict temperature
distribution. This effect generates a thermal contribution to the red tilt of
this spectrum, additional to its vacuum component. In the cosmological model
with a large number of free fields conformally coupled to gravity the magnitude
of this effect is determined by the Gauss-Bonnet coefficient
$\mbox{\boldmath$a$}$ of the trace anomaly. For low spins it is too small to be
presently observable, but it can be amplified by the mechanism of the
$\mbox{\boldmath$a$}$-theorem applied to the renormalization group flow which
interpolates between the ultraviolet and infrared domains associated
respectively with early and late stages of cosmological evolution.


title:
Construction of a Gas Electron Multiplier (GEM) Detector for Medical
  Imaging

abstract:
  A prototype Gas Electron Multiplier (GEM) detector is under construction for
medical imaging purposes. A single thick GEM of size 10x10 cm^2 is assembled
inside a square shaped air-tight box which is made of Perspex glass. In order
to ionize gas inside the drift field two types of voltage supplier circuits
were fabricated, and array of 2x4 pads of each size 4x8 mm^2 were utilized for
collecting avalanche charges. Preliminary testing results show that the circuit
which produces high voltage and low current is better than that of low voltage
and high current supplier circuit in terms of x-ray signal counting rates.


title:
Heat kernel bounds for elliptic partial differential operators in
  divergence form with Robin-type boundary conditions II

abstract:
  The principal aim of this short note is to extend a recent result on Gaussian
heat kernel bounds for self-adjoint $L^2(\Om; d^n x)$-realizations, $n\in\bbN$,
$n\geq 2$, of divergence form elliptic partial differential expressions $L$
with (nonlocal) Robin-type boundary conditions in bounded Lipschitz domains
$\Om \subset \bbR^n$, where $$ Lu = - \sum_{j,k=1}^n\partial_j
a_{j,k}\partial_k u. $$ The (nonlocal) Robin-type boundary conditions are then
of the form $$ \nu\cdot A\nabla u + \Theta\big[u\big|_{\partial\Om}\big]=0 \,
\text{on} \, \partial\Omega, $$ where $\Theta$ represents an appropriate
operator acting on Sobolev spaces associated with the boundary $\partial \Om$
of $\Om$, and $\nu$ denotes the outward pointing normal unit vector on
$\partial\Om$.


title:
Uniform hyperbolicity and its relation with spectral analysis of 1D
  discrete Schr\"odinger Operators

abstract:
  This paper intends to provide new, simple, and self-contained proofs of the
equivalence of various different descriptions of the uniformly hyperbolic
$\mathrm{SL}(2,\mathbb R)$ sequences. While in the scenario of the
Schr\"odinger cocyles, they may in turn be applied to give new and simple
proofs of theorems regarding their relation with the spectral analysis of
one-dimensional discrete Schr\"odinger operators. Concretely, this paper gives
four different descriptions of uniformly hyperbolic sequences together with the
detailed proofs of their equivalence. It provides concise and self-contained
proof of the Johnson's Theorem [Jo], both for sequence and dynamically defined
potentials. In particular, we give two different proofs of the direction
`uniform hyperbolicity away from the spectrum', of which one is the standard
argument in the spirit of Russell Johnson's original proof and the other
involves Combes-Thomas type of estimate [CT]. Finally, the relation between the
Avalanche Principle, discovered by Goldstein-Schlag [GS], and the uniformly
hyperbolic sequence is explored which yields a simple proof and a better
version of the Avalanche Principle. Many ingredients of the proofs in this
paper are new, in particular the use of asymptotic stable and unstable
directions, are of independent interest and have been applied to many other
related problems.


title: Statistics of Superior Records

abstract:
  We study statistics of records in a sequence of random variables. These
identical and independently distributed variables are drawn from the parent
distribution rho. The running record equals the maximum of all elements in the
sequence up to a given point. We define a superior sequence as one where all
running records are above the average record, expected for the parent
distribution rho. We find that the fraction of superior sequences S_N decays
algebraically with sequence length N, S_N ~ N^{-beta} in the limit N-->infty.
Interestingly, the decay exponent beta is nontrivial, being the root of an
integral equation. For example, when rho is a uniform distribution with compact
support, we find beta=0.450265. In general, the tail of the parent distribution
governs the exponent beta. We also consider the dual problem of inferior
sequences, where all records are below average, and find that the fraction of
inferior sequences I_N decays algebraically, albeit with a different decay
exponent, I_N ~ N^{-alpha}. We use the above statistical measures to analyze
earthquake data.

categories: cond-mat.stat-mech math.PR math.ST stat.TH


title:
The state-of-the-art in web-scale semantic information processing for
  cloud computing

abstract:
  Based on integrated infrastructure of resource sharing and computing in
distributed environment, cloud computing involves the provision of dynamically
scalable and provides virtualized resources as services over the Internet.
These applications also bring a large scale heterogeneous and distributed
information which pose a great challenge in terms of the semantic ambiguity. It
is critical for application services in cloud computing environment to provide
users intelligent service and precise information. Semantic information
processing can help users deal with semantic ambiguity and information overload
efficiently through appropriate semantic models and semantic information
processing technology. The semantic information processing have been
successfully employed in many fields such as the knowledge representation,
natural language understanding, intelligent web search, etc. The purpose of
this report is to give an overview of existing technologies for semantic
information processing in cloud computing environment, to propose a research
direction for addressing distributed semantic reasoning and parallel semantic
computing by exploiting semantic information newly available in cloud computing
environment.