title:
Statistical Network Analysis for Functional MRI: Summary Networks and
  Group Comparisons

abstract:
  Comparing weighted networks in neuroscience is hard, because the topological
properties of a given network are necessarily dependent on the number of edges
of that network. This problem arises in the analysis of both weighted and
unweighted networks. The term density is often used in this context, in order
to refer to the mean edge weight of a weighted network, or to the number of
edges in an unweighted one. Comparing families of networks is therefore
statistically difficult because differences in topology are necessarily
associated with differences in density. In this review paper, we consider this
problem from two different perspectives, which include (i) the construction of
summary networks, such as how to compute and visualize the mean network from a
sample of network-valued data points; and (ii) how to test for topological
differences, when two families of networks also exhibit significant differences
in density. In the first instance, we show that the issue of summarizing a
family of networks can be conducted by adopting a mass-univariate approach,
which produces a statistical parametric network (SPN). In the second part of
this review, we then highlight the inherent problems associated with the
comparison of topological functions of families of networks that differ in
density. In particular, we show that a wide range of topological summaries,
such as global efficiency and network modularity are highly sensitive to
differences in density. Moreover, these problems are not restricted to
unweighted metrics, as we demonstrate that the same issues remain present when
considering the weighted versions of these metrics. We conclude by encouraging
caution, when reporting such statistical comparisons, and by emphasizing the
importance of constructing summary networks.


title:
Constraining dark matter late-time energy injection: decays and p-wave
  annihilations

abstract:
  We use the latest cosmic microwave background (CMB) observations to provide
updated constraints on the dark matter lifetime as well as on p-wave suppressed
annihilation cross sections in the 1 MeV to 1 TeV mass range. In contrast to
scenarios with an s-wave dominated annihilation cross section, which mainly
affect the CMB close to the last scattering surface, signatures associated with
these scenarios essentially appear at low redshifts ($z \lesssim 50$) when
structure began to form, and thus manifest at lower multipoles in the CMB power
spectrum. We use data from Planck, WMAP9, SPT and ACT, as well as
Lyman-$\alpha$ measurements of the matter temperature at $z \sim 4$ to set a 95
% confidence level lower bound on the dark matter lifetime of $\sim 4 \times
10^{25}$ s for $m_\chi = 100$ MeV. This bound becomes lower by an order of
magnitude at $m_\chi = 1$ TeV due to inefficient energy deposition into the
intergalactic medium. We also show that structure formation can enhance the
effect of p--wave suppressed annihilation cross sections by many orders of
magnitude with respect to the background cosmological rate, although even with
this enhancement, CMB constraints are not yet strong enough to reach the
thermal relic value of the cross section.


title:
Geometric spin Hall effect of light in tightly focused polarization
  tailored light beams

abstract:
  Recently, it was shown that a non-zero transverse angular momentum manifests
itself in a polarization dependent intensity shift of the barycenter of a
paraxial light beam [A. Aiello et al., Phys. Rev. Lett. 103, 100401 (2009)].
The underlying effect is phenomenologically similar to the spin Hall effect of
light, but does not depend on the specific light-matter interaction and can be
interpreted as a purely geometric effect. Thus, it was named the geometric spin
Hall effect of light. Here, we experimentally investigate the appearance of
this effect in tightly focused vector-beams. We use an experimental
nano-probing technique in combination with a reconstruction algorithm to verify
the relative shifts of the components of the electric energy density in the
focal plane, which are linked to the intensity shift. By that, we
experimentally demonstrate the geometric spin Hall effect of light in a focused
light beam.


title:
The X-ray properties of the black hole transient MAXI J1659-152 in
  quiescence

abstract:
  We present new Chandra X-ray observations of the transient black hole X-ray
binary MAXI J1659-152 in quiescence. These observations were made more than one
year after the end of the source's 2010-2011 outburst. We detect the source at
a 0.5-10 keV flux of 2.8(8)e-15 erg/cm^2/s, which corresponds to a luminosity
of ~1.2e31 (d/ 6 kpc)^2 erg/s. This level, while being the lowest at which the
source has been detected, is within factors of ~2 of the levels seen at the end
of the initial decay of the outburst and soon after a major reflare of the
source. The quiescent luminosity of MAXI J1659-152, which is the
shortest-orbital-period black hole X-ray binary (~2.4 hr), is lower than that
of neutron-star X-ray binaries with similar periods. However, it is higher than
the quiescent luminosities found for black hole X-ray binaries with orbital
periods ~2-4 times longer. This could imply that a minimum quiescent luminosity
may exist for black hole X-ray binaries, around orbital periods of ~5-10 hr, as
predicted by binary-evolution models for the mass transfer rate. Compared to
the hard state we see a clear softening of the power-law spectrum in
quiescence, from an index of 1.55(4) to an index of 2.5(4). We constrain the
luminosity range in which this softening starts to fractional Eddington
luminosities of (0.18-6.2)e-5 (d/ 6 kpc)^2 (M/ 8 Msun), which is consistent
with the ranges inferred for other sources.


title: A Simple Circle Discretization Algorithm With Applications

abstract:
  In CNC manufacturing,there often arises the need to create G-Code programs
which require the calculation of discrete x-y coordinate pairs(2D).An example
of this situation is when the programmer needs to create a program to machine a
helix(or thread).The required toolpath will be a set of points on a helix
curve.The problem now entails calculating the number of points along this
curve.Too few points and the toolpath will not be smooth.Too many points and
the program becomes too big.This article will serve to provide a simple way to
divide a circle into discrete points,with a notion of "dimensional tolerance"
built into the algorithm.


title:
Multi-orbital Effects on Thermoelectric Properties of Strongly
  Correlated Materials

abstract:
  The effects of electronic correlations and orbital degeneracy on
thermoelectric properties are studied within the context of multi-orbital
Hubbard models on different lattices. We use dynamical mean field theory with
iterative perturbation theory as a solver to calculate the self-energy of the
models in wide range of interaction strengths. The Seebeck coefficient, which
measures the voltage drop in response to a temperature gradient across the
system, shows a non-monotonic behavior with temperatures in the presence of
strong correlations. This anomalous behavior is associated with a crossover
from a Fermi liquid metal at low temperatures to a bad metal with incoherent
excitations at high temperatures. We find that for interactions comparable to
the bandwidth the Seebeck coefficient acquires large values at low
temperatures. Moreover, for strongly correlated cases, where the interaction is
larger than the band width, the figure of merit is enhanced over a wide range
of temperatures because of decreasing electronic contributions to the thermal
conductivity. We also find that multi-orbital systems will typically yield
larger thermopower compared to single orbital models.


title: On the infinity category of homotopy Leibniz algebras

abstract:
  We discuss various concepts of $\infty$-homotopies, as well as the relations
between them (focussing on the Leibniz type). In particular
$\infty$-$n$-homotopies appear as the $n$-simplices of the nerve of a complete
Lie ${\infty}$-algebra. In the nilpotent case, this nerve is known to be a Kan
complex \cite{Get09}. We argue that there is a quasi-category of
$\infty$-algebras and show that for truncated $\infty$-algebras, i.e.
categorified algebras, this $\infty$-categorical structure projects to a strict
2-categorical one. The paper contains a shortcut to $(\infty,1)$-categories, as
well as a review of Getzler's proof of the Kan property. We make the latter
concrete by applying it to the 2-term $\infty$-algebra case, thus recovering
the concept of homotopy of \cite{BC04}, as well as the corresponding
composition rule \cite{SS07}. We also answer a question of \cite{BS07} about
composition of $\infty$-homotopies of $\infty$-algebras.


title: On Endomorphism Rings of Local Cohomology Modules

abstract:
  Let I be an ideal of a Complete Cohen-Macaulay local ring R of dimension n.
We wil show that the natural homomorphism Rto HomR(HcI(KR), HcI(KR)) is an
isomorphism provided that I is a cohomologically compltete intersection ideal
of grade c where KR (resp. HiI(.)) denote the canonical module (resp. i-th
local cohomology with respect to the ideal I) of R. The same result is true for
the Matlis dual of HcI(KR).


title: Prototype studies for a forward EM calorimeter in ALICE

abstract:
  A forward electromagnetic calorimeter (FoCal) based on SiW technology is
being considered as a possible upgrade to the ALICE detector. This device
should in particular feature an extremely high granularity allowing gamma/pi0
discrimination out to very high momenta. The main option considered for the
high granularity layers is the use of CMOS pixel sensors. We will discuss the
motivation and design principles of the proposed calorimeter and will then
focus on the experience gained with a full CMOS-pixel calorimeter prototype.
Preliminary results of this device show very good capabilities for shower
profile measurements, and reasonable results for linearity and resolution,
which are limited by the currently incomplete calibration.


title: Notes of the Summer School on Finite Set Statistics

abstract:
  This document contains the notes of some of the lectures given at the first
summer school on Finite Set Statistics held in Edinburgh from July 22, 2013 to
July 26, 2013. The notes are mostly self contained and are accessible to
everyone.


title: Differential Graded Categories are k-linear Stable Infinity Categories

abstract:
  We describe a comparison between pretriangulated differential graded
categories and certain stable infinity categories. Specifically, we use a model
category structure on differential graded categories over k (a field of
characteristic 0) where the weak equivalences are the Morita equivalences, and
where the fibrant objects are in particular pretriangulated differential graded
categories. We show the underlying infinity category of this model category is
equivalent to the infinity category of k-linear stable infinity categories.


title: A note on the real coarse Baum-Connes conjecture

abstract:
  We document some versions, in real K-theory, of well-known properties of the
coarse assembly map in complex K-theory. These results are well-known, but
difficult to find in the literature.


title:
Measurement of the B+ --> omega l+ nu branching fraction with
  semileptonically tagged B mesons

abstract:
  We report a measurement of the branching fraction of the exclusive charmless
semileptonic decay B+ --> omega l+ nu, where l is either an electron or a muon.
We use samples of B+ mesons tagged by a reconstructed charmed semileptonic
decay of the other B meson in the event. The measurement is based on a dataset
of 426.1 fb-1 of e+e- collisions at a center-of-mass energy of 10.58 GeV
recorded with the BABAR detector at the PEP-II asymmetric-energy e+e- storage
rings. We measure a branching fraction of BF(B+ --> omega l+ nu) = (1.35 +/-
0.21 +/- 0.11) x 10(-4), where the uncertainties are statistical and
systematic, respectively. We also present measurements of the partial branching
fractions in three bins of q2, the invariant-mass squared of the
lepton-neutrino system, and we compare them to theoretical predictions of the
form factors.


title:
Parallelization of an implicit algorithm for multi-dimensional
  particle-in-cell simulations

abstract:
  The implicit 2D3V particle-in-cell (PIC) code developed to study the
interaction of ultrashort pulse lasers with matter [G. M. Petrov and J. Davis,
Computer Phys. Comm. 179, 868 (2008); Phys. Plasmas 18, 073102 (2011)] has been
parallelized using MPI (Message Passing Interface). Details on the algorithm
implementation are given with emphasis on code optimization by overlapping
computations with communications. Performance evaluation has been made on a
small Linux cluster with 32 processors for two typical regimes of PIC
operation: "particle dominated", for which the bulk of the computation time is
spent on pushing particles, and "field dominated", for which computing the
fields is prevalent. We found that the MPI implementation of the code offers a
significant numerical speedup. In the "particle dominated" regime it is close
to the maximum theoretical one, while in the other regime it is about 75-80 %
of the maximum speed-up. The code parallelization will allow future
implementation of atomic physics and extension to three dimensions.


title: Alpha current flow betweenness centrality

abstract:
  A class of centrality measures called betweenness centralities reflects
degree of participation of edges or nodes in communication between different
parts of the network. The original shortest-path betweenness centrality is
based on counting shortest paths which go through a node or an edge. One of
shortcomings of the shortest-path betweenness centrality is that it ignores the
paths that might be one or two steps longer than the shortest paths, while the
edges on such paths can be important for communication processes in the
network. To rectify this shortcoming a current flow betweenness centrality has
been proposed. Similarly to the shortest path betwe has prohibitive complexity
for large size networks. In the present work we propose two regularizations of
the current flow betweenness centrality, \alpha-current flow betweenness and
truncated \alpha-current flow betweenness, which can be computed fast and
correlate well with the original current flow betweenness.


title: Sparse Command Generator for Remote Control

abstract:
  In this article, we consider remote-controlled systems, where the command
generator and the controlled object are connected with a bandwidth-limited
communication link. In the remote-controlled systems, efficient representation
of control commands is one of the crucial issues because of the bandwidth
limitations of the link. We propose a new representation method for control
commands based on compressed sensing. In the proposed method, compressed
sensing reduces the number of bits in each control signal by representing it as
a sparse vector. The compressed sensing problem is solved by an L1-L2
optimization, which can be effectively implemented with an iterative shrinkage
algorithm. A design example also shows the effectiveness of the proposed
method.


title:
Numerical modelling of Ar glow discharge at intermediate and high
  pressures

abstract:
  A detailed collisional-radiative model for Ar at intermediate and high
pressures is developed. The model is coupled with the electron Boltzmann
equation and includes several highly excited Ar states and charged particles.
The densities of all neutral and charged species considered are calculated
self-consistently. Detailed information concerning the electronic data used is
presented. The model will be further used for analysing the contraction
phenomena in noble gas discharges and eventually for theoretical description of
the kinetic properties of high pressure Ar excimer laser.


title:
Upper bound for the counting function of interior transmission
  eigenvalues

abstract:
  For the complex interior transmission eigenvalues (ITE) we study for small
$\theta > 0$ the counting function $$N(\theta, r) = #\{\lambda \in \C:\:
\lambda \: {\rm is} \: {\rm (ITE)},\: |\lambda| \leq r, \: 0 \leq \arg \lambda
\leq \theta\}.$$ We obtain for fixed $\theta > 0$ an upper bound $N(\theta, r)
\leq C r^{n/2}, \: r \geq r(\theta).$


title: Fluctuation relations for anisotropic systems

abstract:
  Currents of particles or energy in driven nonequilibrium steady states are
known to satisfy certain symmetries, referred to as fluctuation relations,
determining the ratio of the probabilities of positive fluctuations to negative
ones. A generalization of these fluctuation relations has been proposed
recently for extended nonequilibrium systems of dimension greater than one,
assuming, crucially, that they are isotropic [P. I.\ Hurtado, C.\
P\'erez-Espigares, J. J.\ del Pozo, and P. L.\ Garrido, Proc.\ Nat.\ Acad.\
Sci.\ (USA) \textbf{108}, 7704 (2011)]. Here we relax this assumption and
derive a fluctuation relation for $d$-dimensional systems having anisotropic
bulk driving rates. We illustrate this anisotropic fluctuation relation for the
particle current fluctuations in the 2-$d$ anisotropic zero-range process,
using both exact and fluctuating hydrodynamic approaches.


title:
Making giant planet cores: convergent migration and growth of planetary
  embryos in non-isothermal discs

abstract:
  Earth-mass bodies are expected to undergo Type I migration directed either
inward or outward depending on the thermodynamical state of the protoplanetary
disc. Zones of convergent migration exist where the Type I torque cancels out.
We study the evolution of multiple protoplanets of a few Earth masses embedded
in a non-isothermal protoplanetary disc. The protoplanets are located in the
vicinity of a convergence zone located at the transition between two different
opacity regimes. Inside the convergence zone, Type I migration is directed
outward and outside the zone migration is directed inward. We used a grid-based
hydrodynamical code that includes radiative effects. We performed simulations
varying the initial number of embryos and tested the effect of including
stochastic forces to mimic the effects resulting from turbulence. We also
performed N-body runs calibrated on hydrodynamical calculations to follow the
evolution on Myr timescales. For a small number of initial embryos (N = 5-7)
and in the absence of stochastic forcing, the population of protoplanets
migrates convergently toward the zero-torque radius and forms a stable resonant
chain that protects embryos from close encounters. In systems with a larger
initial number of embryos, or in which stochastic forces were included, these
resonant configurations are disrupted. This in turn leads to the growth of
larger cores via a phase of giant impacts, after which the system settles to a
new stable resonant configuration. Giant planets cores with masses of 10 Earth
masses formed in about half of the simulations with initial protoplanet masses
of m_p = 3 Earth masses but in only 15% of simulations with m_p = 1 Earth mass.
This suggests that if ~2-3 Earth mass protoplanets can form in less than ~1
Myr, convergent migration and giant collisions can grow giant planet cores at
Type I migration convergence zones.


title:
A framework for systematic analysis of Open Access journals and its
  application in software engineering and information systems

abstract:
  This article is a contribution towards an understanding of Open Access (OA)
publishing. It proposes an analysis framework of 18 core attributes, divided
into the areas of Bibliographic information, Activity metrics, Economics,
Accessibility, and Predatory issues of OA journals. The framework has been
employed in a systematic analysis of 30 OA journals in software engineering
(SE) and information systems (IS), which were selected among 386 OA journals in
Computer Science from the Directory of OA Journals. An analysis is performed on
the sample of the journals, to provide an overview of the current situation of
OA journals in the fields of SE and IS. The journals are then compared
between-group, according to the presence of a publication fee. A within-group
analysis is performed on the journals requesting publication charges to
authors, in order to understand what is the value added according to different
price ranges. This article offers several contributions. It presents an
overview of OA definitions and models. It provides an analysis framework born
from the observation of data and the literature. It raises the need to study OA
in the fields of SE and IS while offering a first analysis. Finally, it
provides recommendations to readers of OA journals. This paper highlights
several concerns still threatening OA publishing in the fields of SE and IS.
Among them, it is shown that high publication fees are not sufficiently
justified by the publishers, which often lack transparency and may prevent
authors from adopting OA.


title:
Damped Ly{\alpha} Absorption Systems in Semi-Analytic Models with
  Multiphase Gas

abstract:
  We investigate the properties of damped Ly{\alpha} absorption systems (DLAs)
in semi-analytic models of galaxy formation, including partitioning of cold gas
in galactic discs into atomic, molecular, and ionized phases with a molecular
gas-based star formation recipe. We investigate two approaches for partitioning
gas into these constituents: a pressure-based and a metallicity-based recipe.
We identify DLAs by passing lines of sight through our simulations to compute
HI column densities. We find that models with "standard" gas radial profiles -
where the average specific angular momentum of the gas disc is equal to that of
the host dark matter halo - fail to reproduce the observed column density
distribution of DLAs. These models also fail to reproduce the distribution of
velocity widths {\Delta}v, overproducing low {\Delta}v relative to high
{\Delta}v systems. Models with "extended" radial gas profiles - corresponding
to gas discs with higher specific angular momentum - are able to reproduce
quite well the column density distribution of absorbers over the column density
range 19 < log NHI < 22.5 in the redshift range 2 < z < 3.5. The model with
pressure-based gas partitioning also reproduces the observed line density of
DLAs, HI gas density, and {\Delta}v distribution at z < 3 remarkably well.
However all of the models investigated here underproduce DLAs and the HI gas
density at z > 3. If this is the case, the flatness in the number of DLAs and
HI gas density over the redshift interval 0 < z < 5 may be due to a cosmic
coincidence where the majority of DLAs at z > 3 arise from intergalactic gas in
filaments while those at z < 3 arise predominantly in galactic discs. We
further investigate the dependence of DLA metallicity on redshift and
{\Delta}v, and find reasonably good agreement with the observations,
particularly when including the effects of metallicity gradients (abbrv.).


title: Parameterized Rural Postman Problem

abstract:
  The Directed Rural Postman Problem (DRPP) can be formulated as follows: given
a strongly connected directed multigraph $D=(V,A)$ with nonnegative integral
weights on the arcs, a subset $R$ of $A$ and a nonnegative integer $\ell$,
decide whether $D$ has a closed directed walk containing every arc of $R$ and
of total weight at most $\ell$. Let $k$ be the number of weakly connected
components in the the subgraph of $D$ induced by $R$. Sorge et al. (2012) ask
whether the DRPP is fixed-parameter tractable (FPT) when parameterized by $k$,
i.e., whether there is an algorithm of running time $O^*(f(k))$ where $f$ is a
function of $k$ only and the $O^*$ notation suppresses polynomial factors.
Sorge et al. (2012) note that this question is of significant practical
relevance and has been open for more than thirty years. Using an algebraic
approach, we prove that DRPP has a randomized algorithm of running time
$O^*(2^k)$ when $\ell$ is bounded by a polynomial in the number of vertices in
$D$. We also show that the same result holds for the undirected version of
DRPP, where $D$ is a connected undirected multigraph.


title:
An Enhanced Time Space Priority Scheme to Manage QoS for Multimedia
  Flows transmitted to an end user in HSDPA Network

abstract:
  When different type of packets with different needs of Quality of Service
(QoS) requirements share the same network resources, it became important to use
queue management and scheduling schemes in order to maintain perceived quality
at the end users at an acceptable level. Many schemes have been studied in the
literature, these schemes use time priority (to maintain QoS for Real Time (RT)
packets) and/or space priority (to maintain QoS for Non Real Time (NRT)
packets). In this paper, we study and show the drawback of a combined time and
space priority (TSP) scheme used to manage QoS for RT and NRT packets intended
for an end user in High Speed Downlink Packet Access (HSDPA) cell, and we
propose an enhanced scheme (Enhanced Basic-TSP scheme) to improve QoS
relatively to the RT packets, and to exploit efficiently the network resources.
A mathematical model for the EB-TSP scheme is done, and numerical results show
the positive impact of this scheme.


title:
Drag effect and Cooper electron-hole pair fluctuations in a topological
  insulator film

abstract:
  Manifestations of fluctuating Cooper pairs formed by electrons and holes
populating opposite surfaces of a topological insulator film in the Coulomb
drag effect are considered. Fluctuational Aslamazov-Larkin contribution to the
transresistance between surfaces of the film is calculated. The contribution is
the most singular one in the vicinity of critical temperature $T_\mathrm{d}$
and diverges in the critical manner as $(T-T_\mathrm{d})^{-1}$. In the
realistic conditions $\gamma\sim T_\mathrm{d}$, where $\gamma$ is average
scattering rate of electrons and holes, Aslamazov-Larkin contribution plays
important role and can dominate the fluctuation transport. The macroscopic
theory based on time-dependent Ginzburg-Landau equation is developed for
description of the fluctuational drag effect in the system. The results can be
easily generalized for other realizations of electron-hole bilayer.


title: Contributions to Pion Decay from Lorentz Violation in the Weak Sector

abstract:
  Lorentz violation in the weak sector would affect the beta-decay lifetimes of
pions. The decay amplitude may be rendered anisotropic, but only an isotropic
violation of boost invariance can affect the net lifetime in the center of mass
frame. However, since the rest frames of the pions that produce the NuMI
neutrino beam at Fermilab vary with the rotation of the Earth, it is possible
to constrain anisotropic Lorentz violation using prior analyses of sidereal
variations in the event rate at the MINOS near detector. The resulting bounds
on weak-sector Lorentz violation are at the 10^(-4) level, a substantial
improvement over previous results. The highly relativistic character of the
pions involved is responsible for the improvement.


title: Canonical Transformations in Crystals

abstract:
  The space representations of linear canonical transformations were studied by
Moshinsky and Quesne in 1972. For a few decades, the bilinear hamiltonian
remained as the only exactly solvable representative for such problems. In this
work we show that the Mello-Moshinsky equations can be solved exactly for a
class of problems with discrete symmetry, leading to exact propagators for
Wannier-Stark ladders in one and two dimensional crystals. We give a detailed
study for a particle in a triangular lattice under the influence of a
time-dependent electric field. A more general set of Mello-Moshinsky equations
for arbitrary lattices is presented.


title: On algebraic spaces with an action of G_m

abstract:
  Let Z be an algebraic space of finite type over a field, equipped with an
action of the multiplicative group $G_m$. In this situation we define and study
a certain algebraic space equipped with an unramified morphism to $A^1\times
Z\times Z$, where $A^1$ is the affine line. (If Z is affine and smooth this is
just the closure of the graph of the action map $G_m\times Z\to Z$.)
  In articles joint with D.Gaitsgory we use this set-up to prove a new result
in the geometric theory of automorphic forms and to give a new proof of a very
important theorem of T. Braden.


title:
Formation of Nickel-Platinum Silicides on a Silicon Substrate:
  Structure, Phase Stability, and Diffusion from Ab initio Computations

abstract:
  The formation of Ni(Pt)silicides on a Si(001) surface is investigated using
an ab initio approach. After deposition of a Ni overlayer alloyed with Pt, the
calculations reveal fast diffusion of Ni atoms into the Si lattice, which leads
initially to the formation of Ni2Si. At the same time Si atoms are found to
diffuse into the metallic overlayer. The transformation of Ni2Si into NiSi is
likely to proceed via a vacancy-assisted diffusion mechanism. Silicon atoms are
the main diffusing species in this transformation, migrating from the Si
substrate through the growing NiSi layer into the Ni2Si. Pt atoms have a low
solubility in Ni2Si and prefer Si-sites in the NiSi lattice, thereby
stabilizing the NiSi phase. The diffusivity of Pt is lower than that of Ni.
Furthermore, Pt atoms have a tendency to segregate to interfaces, thereby
acting as diffusion barriers.


title: A Mirror Based Event Cloaking Device

abstract:
  We propose a way of implementing an event cloaking device without the use of
metamaterials. Rather than slowing down and speeding up light, we manipulate an
obscurity gap by diverting the light through paths of appropriate length with
an arrangement of switchable transreflective mirrors.


title: Effect of multiple degrees of ambivalence on the Naming Game

abstract:
  We examine a modified Naming Game in the mean field where there are multiple
degrees of ambivalence. Once an agent in one state fears an opinion one way or
another, he or she moves one step in the appropriate direction. In the absence
of zealots, the two consensus states are stable steady states and the uniform
distribution is an unstable steady state. With zealots for one opinion only,
there is a critical value below which there are three steady states and above
which there is only one. Consensus in favor of the zealots' opinion is the
steady state that always exists, and is stable. The second steady state is the
uniform distribution in the absence of zealots, and moves away from the
zealots' opinion as the number of zealots increases. This state is unstable.
The last steady state starts at consensus against the zealots, and moves toward
the zealots' opinion as the number of zealots increases. This state is stable.
When zealots are added on both sides, the "beak" pattern observed for the
Naming Game remains, with the region of multiple steady states growing with the
addition of more intermediate states.


title:
On the Strong Convergence of the Optimal Linear Shrinkage Estimator for
  Large Dimensional Covariance Matrix

abstract:
  In this work we construct an optimal linear shrinkage estimator for the
covariance matrix in high dimensions. The recent results from the random matrix
theory allow us to find the asymptotic deterministic equivalents of the optimal
shrinkage intensities and estimate them consistently. The developed
distribution-free estimators obey almost surely the smallest Frobenius loss
over all linear shrinkage estimators for the covariance matrix. The case we
consider includes the number of variables $p\rightarrow\infty$ and the sample
size $n\rightarrow\infty$ so that $p/n\rightarrow c\in (0, +\infty)$.
Additionally, we prove that the Frobenius norm of the sample covariance matrix
tends almost surely to a deterministic quantity which can be consistently
estimated.


title: Biorthogonal Quantum Mechanics

abstract:
  The Hermiticity condition in quantum mechanics required for the
characterisation of (a) physical observables and (b) generators of unitary
motions can be relaxed into a wider class of operators whose eigenvalues are
real and whose eigenstates are complete. In this case, the orthogonality of
eigenstates is replaced by the notion of biorthogonality that defines the
relation between the Hilbert space of states and its dual space. The resulting
quantum theory, which might appropriately be called 'biorthogonal quantum
mechanics', is developed here in some detail in the case for which the Hilbert
space dimensionality is finite. Specifically, characterisations of probability
assignment rules, observable properties, pure and mixed states, spin particles,
measurements, combined systems and entanglements, perturbations, and dynamical
aspects of the theory are developed. The paper concludes with a brief
discussion on infinite-dimensional systems.


title:
Connection between beam polarization and systematical errors in storage
  ring electric-dipole-moment experiments

abstract:
  Analysis of spin dynamics in storage ring electric-dipole-moment (EDM)
experiments ascertains that the use of initial vertical beam polarization
allows to cancel spin-dependent systematical errors imitating the EDM effect.
While the use of this polarization meets certain difficulties, it should be
considered as an alternative or supplementary possibility of fulfilling the EDM
experiment.


title:
Validity of the weakly-nonlinear solution of the Cauchy problem for the
  Boussinesq-Ostrovsky equation

abstract:
  We consider the initial-value problem for the regularized
Boussinesq-Ostrovsky equation in the class of periodic functions. Validity of
the weakly-nonlinear solution, given in terms of two counter-propagating waves
satisfying the uncoupled Ostrovsky equations, is examined. We prove
analytically and illustrate numerically that the improved accuracy of the
solution can be achieved at the time scales of the Ostrovsky equation if
solutions of the linearized Ostrovsky equations are incorporated into the
asymptotic solution. Compared to the previous literature, we show that the
approximation error can be controlled in the energy space of periodic functions
and the nonzero mean values of the periodic functions can be naturally
incorporated in the justification analysis.


title: Constant mean curvature spheres in homogeneous three-spheres

abstract:
  We give a complete classification of the immersed constant mean curvature
spheres in a three-sphere with an arbitrary homogenous metric, by proving that
for each $H\in\mathbb{R}$, there exists a constant mean curvature $H$-sphere in
the space that is unique up to an ambient isometry.


title:
Continuous Formation of Vibronic Ground State RbCs Molecules via
  Photoassociation

abstract:
  We demonstrate the direct formation of vibronic ground state RbCs molecules
by photoassociation of ultracold atoms followed by radiative stabilization. The
photoassociation proceeds through deeply-bound levels of the (2)^{3}\Pi_{0^{+}}
state. From analysis of the relevant free-to-bound and bound-to-bound
Franck-Condon factors, we have predicted and experimentally verified a set of
photoassociation resonances that lead to efficient creation of molecules in the
v=0 vibrational level of the X^{1}\Sigma^{+} electronic ground state. We also
compare the observed and calculated laser intensity required to saturate the
photoassociation rate. We discuss the prospects for using short-range
photoassociation to create and accumulate samples of ultracold polar molecules
in their rovibronic ground state.


title: Open Source Physics

abstract:
  Open Source Physics (Brown, 2012; Christian, 2010; Esquembre, 2012; Hwang,
2010) empowers teachers and students to create and use these free tools with
the associated intellectual property rights given to customise (Wee & Mak,
2009) the computer models/tools to suit their teaching and learning needs. Open
Source Physics (OSP) focuses on design of computer models, such as Easy Java
Simulations (EJS) and the use of video modeling and analysis (Tracker). They
allow students to investigate, explore and analyse data which is either real or
simulated. The OSP approach helps users overcome barriers in creating, using
and scaling up meaningful ICT use in education. In Singapore, teachers and
students have created or customised existing computer models to design and
re-purpose EJS models to suit their context and learning needs. Tracker tools
allow students to analyse different aspects of a physics phenomena to deepen
their understanding of abstract physics concepts. Using Tracker, students
record the motion of objects and create their own models to test their ideas in
the study of kinematics. Essentially, the two main pedagogical approaches
(Figure 1) used in OSP are: Guided Inquiry investigating modeled phenomena(EJS)
video analysis (Tracker) Constructionism learning by making new models(EJS)
video modeling(Tracker)


title:
Quantum confinement in perovskite oxide heterostructures: tight binding
  instead of nearly free electron picture

abstract:
  Most recently, orbital-selective quantum well states of $d$ electrons have
been experimentally observed in SrVO$_3$ ultrathin films [K. Yoshimatsu et.
al., Science 333, 319 (2011)] and SrTiO$_3$ surfaces [A. F. Santander-Syro et.
al., Nature 469, 189 (2011)]. Hitherto, one tries to explain these experiments
by a nearly free electron (NFE) model, an approach widely used for delocalized
electrons in semiconductor heterostructures and simple metal films. We show
that a tight binding (TB) model is more suitable for describing
heterostructures with more localized $d$ electrons. In this paper, we construct
from first principles simple TB models for perovskite oxide heterostructures
and surfaces. We show that the TB model provides a simple intuitive physical
picture and yields, already with only two parameters, quantitatively much more
reliable results, consistent with experiment.


title: The effect of ITER-like wall on runaway electron generation in JET

abstract:
  This paper investigates the effect of the ITER-like wall (ILW) on runaway
electron (RE) generation through a comparative study of similar slow argon
injection JET disruptions, performed with different wall materials. In the
carbon wall case, a runaway electron plateau is observed, while in the
ITER-like wall case, the current quench is slower and the runaway current is
negligibly small. The aim of the paper is to shed light on the reason for these
differences by detailed numerical modelling to study which factors affected the
RE formation. The post-disruption current profile is calculated by a
one-dimensional model of electric field, temperature and runaway current taking
into account the impurity injection. Scans of various impurity contents are
performed and agreement with the experimental scenarios is obtained for
reasonable argon- and wall impurity contents. Our modelling shows that the
reason for the changed RE dynamics is a complex, combined effect of the
differences in plasma parameter profiles, the radiation characteristics of
beryllium and carbon, and the difference of the injected argon amount. These
together lead to a significantly higher Dreicer generation rate in the carbon
wall case, which is less prone to be suppressed by RE loss mechanisms. The
results indicate that the differences are greatly reduced above ~50% argon
content, suggesting that significant RE current is expected in future massive
gas injection experiments on both JET and ITER.


title:
Independent Set, Induced Matching, and Pricing: Connections and Tight
  (Subexponential Time) Approximation Hardnesses

abstract:
  We present a series of almost settled inapproximability results for three
fundamental problems. The first in our series is the subexponential-time
inapproximability of the maximum independent set problem, a question studied in
the area of parameterized complexity. The second is the hardness of
approximating the maximum induced matching problem on bounded-degree bipartite
graphs. The last in our series is the tight hardness of approximating the
k-hypergraph pricing problem, a fundamental problem arising from the area of
algorithmic game theory. In particular, assuming the Exponential Time
Hypothesis, our two main results are:
  - For any r larger than some constant, any r-approximation algorithm for the
maximum independent set problem must run in at least
2^{n^{1-\epsilon}/r^{1+\epsilon}} time. This nearly matches the upper bound of
2^{n/r} (Cygan et al., 2008). It also improves some hardness results in the
domain of parameterized complexity (e.g., Escoffier et al., 2012 and Chitnis et
al., 2013)
  - For any k larger than some constant, there is no polynomial time min
(k^{1-\epsilon}, n^{1/2-\epsilon})-approximation algorithm for the k-hypergraph
pricing problem, where n is the number of vertices in an input graph. This
almost matches the upper bound of min (O(k), \tilde O(\sqrt{n})) (by Balcan and
Blum, 2007 and an algorithm in this paper).
  We note an interesting fact that, in contrast to n^{1/2-\epsilon} hardness
for polynomial-time algorithms, the k-hypergraph pricing problem admits
n^{\delta} approximation for any \delta >0 in quasi-polynomial time. This puts
this problem in a rare approximability class in which approximability
thresholds can be improved significantly by allowing algorithms to run in
quasi-polynomial time.


title:
MAGIICAT III. Interpreting Self-Similarity of the Circumgalactic Medium
  with Virial Mass using MgII Absorption

abstract:
  In Churchill et al., we used halo abundance matching applied to 182 galaxies
in the MgII Absorber-Galaxy Catalog (MAGIICAT, Nielsen et al.) and showed that
the mean MgII 2796 equivalent width follows a tight inverse-square power law,
W_r(2796) ~ (D/R_vir)^-2, with projected location relative to the galaxy virial
radius and that the MgII absorption covering fraction is invariant with galaxy
virial mass, M_h, over the range 10.7 < M_h/M_solar < 13.9. In this work, we
explore multivariate relationships between W_r(2796), virial mass, impact
parameter, virial radius, and the theoretical cooling radius that further
elucidate self-similarity in the cool/warm (T=10^{4-4.5} K) circumgalactic
medium (CGM) with virial mass. We show that virial mass determines the extent
and strength of the MgII absorbing gas such that the mean W_r(2796) increases
with virial mass at fixed distance while decreasing with galactocentric
distance for fixed virial mass. The majority of the absorbing gas resides
within D ~ 0.3 R_vir, independent of both virial mass and minimum absorption
threshold; inside this region, and perhaps also in the region 0.3 < D/R_vir =
1, the mean W_r(2796) is independent of virial mass. Contrary to
absorber-galaxy cross-correlation studies, we show there is no anti-correlation
between W_r(2796) and virial mass. We discuss how simulations and theory
constrained by observations fully support self-similarity of the cool/warm CGM
via the physics governing star formation, gas-phase metal enrichment, recycling
efficiency of galactic scale winds, filament and merger accretion, and
overdensity of local environment as a function of virial mass.


title:
Analytical description of ballistic spin currents and torques in
  magnetic tunnel junctions

abstract:
  In this work we demonstrate explicit analytical expressions for both charge
and spin currents which constitute the 2x2 spinor in magnetic tunnel junctions
with noncollinear magnetizations under applied voltage. The calculations have
been performed within the free electron model in the framework of the Keldysh
formalism and WKB approximation. We demonstrate that spin/charge currents and
spin transfer torques are all explicitly expressed through only three
irreducible quantities, without further approximations. The conditions and
mechanisms of deviation from the conventional sine angular dependence of both
spin currents and torques are shown and discussed. It is shown in the thick
barrier approximation that all tunneling transport quantities can be expressed
in an extremely simplified form via Slonczewski spin polarizations and our
effective spin averaged interfacial transmission probabilities and effective
out-of-plane polarizations at both interfaces. It is proven that the latter
plays a key role in the emergence of perpendicular spin torque as well as in
the angular dependence character of all spin and charge transport considered.
It is demonstrated directly also that for any applied voltage, the parallel
component of spin current at the FM/I interface is expressed via collinear
longitudinal spin current components. Finally, spin transfer torque behavior is
analyzed in a view of transverse characteristic length scales for spin
transport.


title:
Sufficient Conditions for Feasibility and Optimality of Real-Time
  Optimization Schemes - I. Theoretical Foundations

abstract:
  The idea of iterative process optimization based on collected output
measurements, or "real-time optimization" (RTO), has gained much prominence in
recent decades, with many RTO algorithms being proposed, researched, and
developed. While the essential goal of these schemes is to drive the process to
its true optimal conditions without violating any safety-critical, or "hard",
constraints, no generalized, unified approach for guaranteeing this behavior
exists. In this two-part paper, we propose an implementable set of conditions
that can enforce these properties for any RTO algorithm. The first part of the
work is dedicated to the theory behind the sufficient conditions for
feasibility and optimality (SCFO), together with their basic implementation
strategy. RTO algorithms enforcing the SCFO are shown to perform as desired in
several numerical examples - allowing for feasible-side convergence to the
plant optimum where algorithms not enforcing the conditions would fail.


title:
Radio Sources Embedded in the Dense Core B59, the "Mouthpiece" of the
  Pipe Nebula

abstract:
  We present Very Large Array continuum observations made at 8.3 GHz toward the
dense core B59, in the Pipe Nebula. We detect six compact sources, of which
five are associated with the five most luminous sources at 70 micrometer in the
region, while the remaining one is probably a background source. We propose
that the radio emission is free-free from the ionized outflows present in these
protostars. We discuss the kinematical impact of these winds in the cloud. We
also propose that these winds are optically thick in the radio but optically
thin in the X-rays and that this characteristic can explain why X-rays from the
magnetosphere are detected in three of them, while the radio emission is most
probably dominated by the free-free emission from the external layers of the
wind.


title: Six-Dimensional (1,0) Superconformal Models and Higher Gauge Theory

abstract:
  We analyze the gauge structure of a recently proposed superconformal field
theory in six dimensions. We find that this structure amounts to a weak
Courant-Dorfman algebra, which, in turn, can be interpreted as a strong
homotopy Lie algebra. This suggests that the superconformal field theory is
closely related to higher gauge theory, describing the parallel transport of
extended objects. Indeed we find that, under certain restrictions, the field
content and gauge transformations reduce to those of higher gauge theory. We
also present a number of interesting examples of admissible gauge structures
such as the structure Lie 2-algebra of an abelian gerbe, differential crossed
modules, the 3-algebras of M2-brane models and string Lie 2-algebras.


title: Fluids in porous media: The case of neutral walls

abstract:
  The bulk phase behavior of a fluid is typically altered when the fluid is
brought into confinement by the walls of a random porous medium. Inside the
porous medium, phase transition points are shifted, or may disappear
altogether. A crucial determinant is how the walls interact with the fluid
particles. In this work, we consider the situation whereby the walls are
neutral with respect to the liquid and vapor phase. In order to realize the
condition of strict neutrality, we use a symmetric binary mixture inside a
porous medium that interacts identically with both of the mixture species.
Monte Carlo simulations are then used to obtain the phase behavior. Our main
finding is that, in the presence of the porous medium, a liquid-vapor type
transition still occurs, but with critical exponents that deviate from bulk
Ising values. In addition, we observe clear violations of self-averaging. These
findings provide further evidence that random confinement by neutral walls
induces critical behavior of the random Ising model (i.e. Ising models with
dilution type disorder, where the disorder couples to the energy).


title: More Evidence for an Oscillation Superimposed on the Hubble Flow

abstract:
  In a recent investigation evidence was presented for a low-level sinusoidal
oscillation superimposed on top of the Hubble flow. This oscillation was in
V$_{CMB}$, in a sample of type Ia Supernovae sources with accurate distances,
and it was found to have a wavelength close to 40 Mpc. It became easily visible
after the removal of several previously identified discrete velocity
components. Its amplitude like that of the Hubble velocity showed an increase
with distance, as would be expected for a constant-amplitude space oscillation.
Here we report that this oscillation is also present in distance clumping in
these sources, with the same wavelength, but in phase quadrature. The discrete
velocity components do not play a role in detecting the distance clumping
wavelength. Assuming that time proceeds from high cosmological redshift to low,
the blue-shifted velocity peaks, which represent the contraction stage of the
velocity oscillation, then lead the density peaks. With the discrete velocity
components removed we also find evidence for at least one other, weaker
velocity oscillation. It is found to have a wavelength similar to one reported
in density clumping by previous investigators. In those cases the source
samples were much larger.


title:
Sufficient Conditions for Feasibility and Optimality of Real-Time
  Optimization Schemes - II. Implementation Issues

abstract:
  The idea of iterative process optimization based on collected output
measurements, or "real-time optimization" (RTO), has gained much prominence in
recent decades, with many RTO algorithms being proposed, researched, and
developed. While the essential goal of these schemes is to drive the process to
its true optimal conditions without violating any safety-critical, or "hard",
constraints, no generalized, unified approach for guaranteeing this behavior
exists. In this two-part paper, we propose an implementable set of conditions
that can enforce these properties for any RTO algorithm. This second part
examines the practical side of the sufficient conditions for feasibility and
optimality (SCFO) proposed in the first and focuses on how they may be enforced
in real application, where much of the knowledge required for the conceptual
SCFO is unavailable. Methods for improving convergence speed are also
considered.


title: On Solving Some Trigonometric Series

abstract:
  This communication shows the track for finding a solution for a sin(kx)/k**2
series and a fresh representation for the Euler's Gamma function in terms of
Riemann's Zeta function. We have found a new series expression for the
logarithm as a side effect. The new series are useful both for analysis,
approximations and asymptotic studies.


title:
Renormalization Group Evolution of the Standard Model Dimension Six
  Operators I: Formalism and lambda Dependence

abstract:
  We calculate the order \lambda, \lambda^2 and \lambda y^2 terms of the 59 x
59 one-loop anomalous dimension matrix of dimension-six operators, where
\lambda and y are the Standard Model Higgs self-coupling and a generic Yukawa
coupling, respectively. The dimension-six operators modify the running of the
Standard Model parameters themselves, and we compute the complete one-loop
result for this. We discuss how there is mixing between operators for which no
direct one-particle-irreducible diagram exists, due to operator replacements by
the equations of motion.


title: Laser-plasma interactions for fast ignition

abstract:
  In the electron-driven fast-ignition approach to inertial confinement fusion,
petawatt laser pulses are required to generate MeV electrons that deposit
several tens of kilojoules in the compressed core of an imploded DT shell. We
review recent progress in the understanding of intense laser plasma
interactions (LPI) relevant to fast ignition. Increases in computational and
modeling capabilities, as well as algorithmic developments have led to
enhancement in our ability to perform multi-dimensional particle-in-cell (PIC)
simulations of LPI at relevant scales. We discuss the physics of the
interaction in terms of laser absorption fraction, the laser-generated electron
spectra, divergence, and their temporal evolution. Scaling with irradiation
conditions such as laser intensity are considered, as well as the dependence on
plasma parameters. Different numerical modeling approaches and configurations
are addressed, providing an overview of the modeling capabilities and
limitations. In addition, we discuss the comparison of simulation results with
experimental observables. In particular, we address the question of surrogacy
of today's experiments for the full-scale fast ignition problem.


title:
Comments on "Wall-plug (AC) power consumption of a very high energy
  e+/e- storage ring collider" by Marc Ross

abstract:
  The paper arXiv:1308.0735 questions some of the technical assumptions made by
the TLEP Steering Group when estimating in arXiv:1305.6498 the power
requirement for the very high energy e+e- storage ring collider TLEP. We show
that our assumptions are based solidly on CERN experience with LEP and the LHC,
as well accelerators elsewhere, and confirm our earlier baseline estimate of
the TLEP power consumption.


title:
Novel Virtual Moving Sound-based Spatial Auditory Brain-Computer
  Interface Paradigm

abstract:
  This paper reports on a study in which a novel virtual moving sound-based
spatial auditory brain-computer interface (BCI) paradigm is developed. Classic
auditory BCIs rely on spatially static stimuli, which are often boring and
difficult to perceive when subjects have non-uniform spatial hearing perception
characteristics. The concept of moving sound proposed and tested in the paper
allows for the creation of a P300 oddball paradigm of necessary target and
non-target auditory stimuli, which are more interesting and easier to
distinguish. We present a report of our study of seven healthy subjects, which
proves the concept of moving sound stimuli usability for a novel BCI. We
compare online BCI classification results in static and moving sound paradigms
yielding similar accuracy results. The subject preference reports suggest that
the proposed moving sound protocol is more comfortable and easier to
discriminate with the online BCI.


title:
Search for direct third-generation squark pair production in final
  states with missing transverse momentum and two b-jets in sqrt{s}=8 TeV pp
  collisions with the ATLAS detector

abstract:
  The results of a search for pair production of supersymmetric partners of the
Standard Model third-generation quarks are reported. This search uses 20.1 fb-1
of pp collisions at sqrt{s}=8 TeV collected by the ATLAS experiment at the
Large Hadron Collider. The lightest bottom and top squarks (b1 and t1
respectively) are searched for in a final state with large missing transverse
momentum and two jets identified as originating from b-quarks. No excess of
events above the expected level of Standard Model background is found. The
results are used to set upper limits on the visible cross section for processes
beyond the Standard Model. Exclusion limits at the 95% confidence level on the
masses of the third-generation squarks are derived in phenomenological
supersymmetric R-parity-conserving models in which either the bottom or the top
squark is the lightest squark. The b1 is assumed to decay via b1->b chi0 and
the t via t1->b chipm, with undetectable products of the subsequent decay of
the chipm due to the small mass splitting between the chipm and the chi0.


title: Polynomials for GL_p x GL_q orbit closures in the flag variety

abstract:
  The subgroup K=GL_p x GL_q of GL_{p+q} acts on the (complex) flag variety
GL_{p+q}/B with finitely many orbits. We introduce a family of polynomials that
specializes to representatives for cohomology classes of the orbit closures in
the Borel model. We define and study K-orbit determinantal ideals to support
the geometric naturality of these representatives. Using a modification of
these ideals, we describe an analogy between two local singularity measures:
the H-polynomials and the Kazhdan-Lusztig-Vogan polynomials.


title: Taylor Expansion Proof of the Matrix Tree Theorem - Part I

abstract:
  The Matrix-Tree Theorem states that the number of spanning trees of a graph
is given by the absolute value of any cofactor of the Laplacian matrix of the
graph. We propose a very short proof of this result which amounts to comparing
Taylor expansions.


title:
AC current generation in chiral magnetic insulators and skyrmion motion
  induced by the spin Seebeck effect

abstract:
  We show that a temperature gradient induces an ac electric current in
multiferroic insulators when the sample is embedded in a circuit. We also show
that a thermal gradient can be used to move magnetic skyrmions in insulating
chiral magnets: the induced magnon flow from the hot to the cold region drives
the skyrmions in the opposite direction via a magnonic spin transfer torque.
Both results are combined to compute the effect of skyrmion motion on the ac
current generation and demonstrate that skyrmions in insulators are a promising
route for spin caloritronics applications.


title:
Boundary systems and (skew-)self-adjoint operators on infinite metric
  graphs

abstract:
  We generalize the notion of Lagrangian subspaces to self-orthogonal subspaces
with respect to a (skew-)symmetric form, thus characterizing
(skew-)self-adjoint and unitary operators by means of self-ortho-gonal
subspaces. By orthogonality preserving mappings, these characterizations can be
transferred to abstract boundary value spaces of (skew-)symmetric operators.
Introducing the notion of boundary systems we then present a unified treatment
of different versions of boundary triples and related concepts treated in the
literature. The application of the abstract results yields a description of all
(skew-)self-adjoint realizations of Laplace and first derivative operators on
graphs.


title:
Particle in cell calculation of plasma force on a small grain in a
  non-uniform collisional sheath

abstract:
  The plasma force on grains of specified charge and height in a collisional DC
plasma sheath are calculated using the multidimensional particle in cell code
COPTIC. The background ion velocity distribution functions for the unperturbed
sheath vary substantially with collisionality. The grain force is found to
agree quite well with a combination of background electric field force plus ion
drag force. However, the drag force must take account of the non-Maxwellian
(and spatially varying) ion distribution function, and the collisional drag
enhancement. It is shown how to translate the dimensionless results into
practical equilibrium including other forces such as gravity.


title:
Nuclear wave packet quantum interference in the intense laser
  dissociation of the $\mathrm{D}_{2}^{+}$ molecule

abstract:
  Recently it has been recognized that electronic conical intersections in
molecular systems can be induced by laser light even in diatomics. As is known
a direct consequence of these accidental degeneracies is the appearence of
nonadiabatic effects which has a strong impact on the nuclear quantum dynamics.
Studying the photodissociation process of the $\mathrm{D}_{2}^{+}$ molecule, we
report here some novel and observable quantum interference phenomena that arise
from the topological singularity induced by a strong laser field.


title: A computability-theoretic reformulation of the Connes Embedding Problem

abstract:
  The Connes Embedding Problem (CEP) asks whether every separable II_1 factor
embeds into an ultrapower of the hyperfinite II_1 factor. We show that the CEP
is equivalent to the computability of the universal theory of every type II_1
von Neumann algebra. We also derive some further computability-theoretic
consequences of the CEP.


title:
Study of Rapid Formation of a Delta Sunspot Associated with the 2012
  July 2 C7.4 Flare Using High-resolution Observations of New Solar Telescope

abstract:
  Rapid, irreversible changes of magnetic topology and sunspot structure
associated with flares have been systematically observed in recent years. The
most striking features include the increase of horizontal field at the polarity
inversion line (PIL) and the co-spatial penumbral darkening. A likely
explanation of the above phenomenon is the back reaction to the coronal
restructuring after eruptions: a coronal mass ejection carries the upward
momentum while the downward momentum compresses the field lines near the PIL.
Previous studies could only use low resolution (above 1") magnetograms and
white-light images. Therefore, the changes are mostly observed for X-class
flares. Taking advantage of the 0.1" spatial resolution and 15s temporal
cadence of the New Solar Telescope at Big Bear Solar Observatory, we report in
detail the rapid formation of sunspot penumbra at the PIL associated with the
C7.4 flare on 2012 July 2. It is unambiguously shown that the solar granulation
pattern evolves to alternating dark and bright fibril structure, the typical
pattern of penumbra. Interestingly, the appearance of such a penumbra creates a
new delta sunspot. The penumbral formation is also accompanied by the
enhancement of horizontal field observed using vector magnetograms from the
Helioseismic and Magnetic Imager. We explain our observations as due to the
eruption of a flux rope following magnetic cancellation at the PIL.
Subsequently the re-closed arcade fields are pushed down towards the surface to
form the new penumbra. NLFFF extrapolation clearly shows both the flux rope
close to the surface and the overlying fields.


title: Gabor Frame Decomposition of Evolution Operators and Applications

abstract:
  We compute the Gabor matrix for Schr\"odinger-type evolution operators.
Precisely, we analyze the Heat Equation, already presented in
\cite{2012arXiv1209.0945C}, giving the exact expression of the Gabor matrix
which leads to better numerical evaluations. Then, using asymptotic integration
techniques, we obtain an upper bound for the Gabor matrix in one-dimension for
the generalized Heat Equation, new in the literature. Using Maple software, we
show numeric representations of the coefficients' decay. Finally, we show the
super-exponential decay of the coefficients of the Gabor matrix for the
Harmonic Repulsor, together with some numerical evaluations. This work is the
natural prosecution of the ideas presented in \cite{2012arXiv1209.0945C} and
\cite{MR2502369}.


title: Detecting activity cycles of late-type dwarfs in Kepler data

abstract:
  Using data of fast-rotating active dwarf stars in the Kepler database, we
perform time-frequency analysis of the light curves in order to search for
signs of activity cycles. We use the phenomenon that the active region
latitudes vary with the cycle (like the solar butterfly diagram), which causes
the observed rotation period to change as a consequence of differential
rotation. We find cycles in 8 cases of the 39 promising targets with periods
between of 300-900 days.


title: Emergent honeycomb lattice in LiZn2Mo3O8

abstract:
  We introduce the idea of emergent lattices, where a simple lattice decouples
into two weakly-coupled lattices as a way to stabilize spin liquids. In
LiZn2Mo3O8, the disappearance of 2/3rds of the spins at low temperatures
suggests that its triangular lattice decouples into an emergent honeycomb
lattice weakly coupled to the remaining spins, and we suggest several ways to
test this proposal. We show that these orphan spins act to stabilize the
spin-liquid in the $J_1-J_2$ honeycomb model and also discuss a possible 3D
analogue, Ba2MoYO6 that may form a "depleted fcc lattice."


title: Stochastic resonance in an RF SQUID with shunted ScS junction

abstract:
  Using a point (superconductor-constriction-superconductor, ScS) contact in a
single-Josephson-junction superconducting quantum interference device (RF
SQUID) provides stochastic resonance conditions at any arbitrary small value of
loop inductance and contact critical current, unlike SQUIDs with more
traditional tunnel (superconductor-insulator-superconductor, SIS) junctions.
This is due to the unusual potential energy of the ScS RF SQUID which always
has a barrier between two wells thus making the device bistable. This paper
presents the results of a numerical simulation of the stochastic dynamics of
the magnetic flux in an ScS RF SQUID loop affected by band-limited white
Gaussian noise and low-frequency sine signals of small and moderate amplitudes.
The difference in stochastic amplification of RF SQUID loops incorporating ScS
and SIS junctions is discussed.


title:
From directed path to linear order - the best choice problem for powers
  of directed path

abstract:
  We examine the evolution of the best choice algorithm and the probability of
its success from a directed path to the linear order of the same cardinality
through $k$th powers of a directed path, $1 \leq k < n$. The vertices of a
$k$th power of a directed path of a known length $n$ are exposed one by one to
a selector in some random order. At any time the selector can see the graph
induced by the vertices that have already come. The selector's aim is to choose
online the maximal vertex (i.e. the vertex with no outgoing edges). It is shown
that the probability of success $p_n$ for the optimal algorithm for the $k$th
power of a directed path satisfies $p_n = \Theta(n^{-1/(k+1)})$. We also
consider the case when the selector knows the distance in the underlying path
between each two vertices that are joined by an edge in the induced graph. An
optimal algorithm for this choice problem is presented. The exact probability
of success when using this algorithm is given.


title:
Improving photon detector efficiency using a high-fidelity optical CNOT
  gate

abstract:
  A significant problem for optical quantum computing is inefficient, or
inaccurate photo-detectors. It is possible to use CNOT gates to improve a
detector by making a large cat state then measuring every qubit in that state.
In this paper we develop a code that compares five different schemes for making
multiple measurements, some of which are capable of detecting loss and some of
which are not. We explore how each of these schemes performs in the presence of
different errors, and derive a formula to find at what probability of qubit
loss is it worth detecting loss, and at what probability does this just lead to
further errors than the loss introduces.


title:
First Observation of the Zb0(10610) in a Dalitz Analysis of Y(5S) ->
  Y(nS) pi0 pi0

abstract:
  We report the first observation of Y(5S) -> Y(nS) pi0 pi0 decays. The neutral
partner of the Zb+-(10610), the Zb0(10610) decaying to Y(2,3S) pi0, is observed
for the first time with a 6.5 sigma significance using a Dalitz analysis of
Y(5S) -> Y(2,3S) pi0 pi0 decays. The results are obtained with a 121.4 fb^-1
data sample collected with the Belle detector at the Y(5S) resonance at the
KEKB asymmetric-energy e+e- collider.


title: Singular degree of a rational matrix pseudodifferential operator

abstract:
  In our previous work we studied minimal fractional decompositions of a
rational matrix pseudodifferential operator: H=A/B, where A and B are matrix
differential operators, and B is non-degenerate of minimal possible degree
deg(B). In the present paper we introduce the singular degree sdeg(H)=deg(B),
and show that for an arbitrary rational expression H=sum_a
(A^a_1)/(B^a_1)...(A^a_n)/(B^a_n), we have that sdeg(H) is less than or equal
to sum_{a,i} deg(B^a_i). If the equality holds, we call such an expression
minimal. We study the properties of the singular degree and of minimal rational
expressions. These results are important for the computations involved in the
Lenard-Magri scheme of integrability.


title:
On maximal inequalities for purely discontinuous martingales in infinite
  dimensions

abstract:
  The purpose of this paper is to give a survey of a class of maximal
inequalities for purely discontinuous martingales, as well as for stochastic
integral and convolutions with respect to Poisson measures, in infinite
dimensional spaces. Such maximal inequalities are important in the study of
stochastic partial differential equations with noise of jump type.


title: On Evaluation of Riesz Constants for Systems of Shifted Gaussians

abstract:
  In this paper we study single-parametric systems of integer shifts of Gauss
and Lorenz functions. In case of Cauchy--Lorenz system we explicitly calculate
nod functions and prove that it tends to sinc function in limit. For both Gauss
and Cauchy--Lorenz systems and corresponding nod functions we explicitly
calculate Riesz constants via trigonometric, hyperbolic and Jacobi
theta-functions, also limit behavior of this values is found depending on
parameters.
  A special result is a sharp monotonicity property proved for a special ratio
of Jacobi theta-functions which is important in many areas. Brief discussion of
numerical methods is included with additional references. Different
applications are outlined to coherent states and atomic spectra.
  Some unsolved problems and comments are added.


title: Continuous-variable dense coding by optomechanical cavities

abstract:
  In this paper, we show how continuous-variable dense coding can be
implemented using entangled light generated from a membrane-in-the-middle
geometry. The mechanical resonator is assumed to be a high reflectivity
membrane hung inside a high quality factor cavity. We show that the mechanical
resonator is able to generate an amount of entanglement between the optical
modes at the output of the cavity, which is strong enough to approach the
capacity of quantum dense coding at small photon numbers. The suboptimal rate
reachable by our optomechanical protocol is high enough to outperform the
classical capacity of the noiseless quantum channel.


title: Cylindrical wormholes with positive cosmological constant

abstract:
  We construct cylindrical, traversable wormholes with finite radii by taking
into account the cut-and-paste procedure for the case of cosmic string
manifolds with a positive cosmological constant. Under reasonable assumptions
about the equation of state of the matter located at the shell, we find that
the wormhole throat undergoes a monotonous evolution provided it moves at a
constant velocity. In order to explore the dynamical nonlinear behaviour of the
wormhole throat, we consider that the matter at the shell is supported by
anisotropic Chaplygin gas, anti-Chaplygin gas, or a mixed of Chaplygin and
anti-Chaplygin gases implying that wormholes could suffer an accelerated
expansion or contraction but the oscillatory behavior seems to be forbidden.


title: A note on the stable equivalence problem

abstract:
  We provide counterexamples to the stable equivalence problem in every
dimension $d\geq2$. That means that we construct hypersurfaces $H_1,
H_2\subset\mathbb{C}^{d+1}$ whose cylinders $H_1\times\mathbb{C}$ and
$H_2\times\mathbb{C}$ are equivalent hypersurfaces in $\mathbb{C}^{d+2}$,
although $H_1$ and $H_2$ themselves are not equivalent by an automorphism of
$\mathbb{C}^{d+1}$. We also give, for every $d\geq2$, examples of two
non-isomorphic algebraic varieties of dimension $d$ which are biholomorphic.


title:
Structure and properties of the algebra of partially transposed
  permutation operators

abstract:
  We consider the structure of algebra of operators, acting in $n-$fold tensor
product space, which are partially transposed on the last term. Using purely
algebraical methods we show that this algebra is semi-simple and then,
considering its regular representation, we derive basic properties of the
algebra. In particular, we describe all irreducible representations of the
algebra of partially transposed operators and derive expressions for matrix
elements of the representations. It appears that there are two types of
irreducible representations of the algebra. The first one is strictly connected
with the representations of the group $S(n-1)$ induced by irreducible
representations of the group $S(n-2)$. The second type is structurally
connected with irreducible representations of the group $S(n-1)$.


title:
Local image registration a comparison for bilateral registration
  mammography

abstract:
  Early tumor detection is key in reducing the number of breast cancer death
and screening mammography is one of the most widely available and reliable
method for early detection. However, it is difficult for the radiologist to
process with the same attention each case, due the large amount of images to be
read. Computer aided detection (CADe) systems improve tumor detection rate; but
the current efficiency of these systems is not yet adequate and the correct
interpretation of CADe outputs requires expert human intervention. Computer
aided diagnosis systems (CADx) are being designed to improve cancer diagnosis
accuracy, but they have not been efficiently applied in breast cancer. CADx
efficiency can be enhanced by considering the natural mirror symmetry between
the right and left breast. The objective of this work is to evaluate
co-registration algorithms for the accurate alignment of the left to right
breast for CADx enhancement. A set of mammograms were artificially altered to
create a ground truth set to evaluate the registration efficiency of DEMONs,
and SPLINE deformable registration algorithms. The registration accuracy was
evaluated using mean square errors, mutual information and correlation. The
results on the 132 images proved that the SPLINE deformable registration
over-perform the DEMONS on mammography images.


title:
KL-based Control of the Learning Schedule for Surrogate Black-Box
  Optimization

abstract:
  This paper investigates the control of an ML component within the Covariance
Matrix Adaptation Evolution Strategy (CMA-ES) devoted to black-box
optimization. The known CMA-ES weakness is its sample complexity, the number of
evaluations of the objective function needed to approximate the global optimum.
This weakness is commonly addressed through surrogate optimization, learning an
estimate of the objective function a.k.a. surrogate model, and replacing most
evaluations of the true objective function with the (inexpensive) evaluation of
the surrogate model. This paper presents a principled control of the learning
schedule (when to relearn the surrogate model), based on the Kullback-Leibler
divergence of the current search distribution and the training distribution of
the former surrogate model. The experimental validation of the proposed
approach shows significant performance gains on a comprehensive set of
ill-conditioned benchmark problems, compared to the best state of the art
including the quasi-Newton high-precision BFGS method.


title: Partially observed Boolean sequences and noise sensitivity

abstract:
  Let $\mathcal{H}$ denote a collection of subsets of $\{1,2,\ldots,n\}$, and
assign independent random variables uniformly distributed over $[0,1]$ to the
$n$ elements. Declare an element $p$-present if its corresponding value is at
most $p$. In this paper, we quantify how much the observation of the
$r$-present ($r>p$) set of elements affects the probability that the set of
$p$-present elements is contained in $\mathcal{H}$. In the context of
percolation, we find that this question is closely linked to the near-critical
regime. As a consequence, we show that for every $r>1/2$, bond percolation on
the subgraph of the square lattice given by the set of $r$-present edges is
almost surely noise sensitive at criticality, thus generalizing a result due to
Benjamini, Kalai and Schramm.


title: Large-N Structure of Tetraquark Mesons

abstract:
  Following Weinberg's argument that narrow tetraquark mesons are not precluded
in large N_c QCD, we explore the flow of N_c factors needed for the consistency
of this picture, and show that they must arise in a novel way, not simply
through the usual combinatoric counting.


title:
Self-mappings of the quaternionic unit ball: multiplier properties,
  Schwarz-Pick inequality, and Nevanlinna--Pick interpolation problem

abstract:
  We study several aspects concerning slice regular functions mapping the
quaternionic open unit ball into itself. We characterize these functions in
terms of their Taylor coefficients at the origin and identify them as
contractive multipliers of the Hardy space. In addition, we formulate and solve
the Nevanlinna-Pick interpolation problem in the class of such functions
presenting necessary and sufficient conditions for the existence and for the
uniqueness of a solution. Finally, we describe all solutions to the problem in
the indeterminate case.


title:
Convex Regularization of Local Volatility Estimation in a Discrete
  Setting

abstract:
  We apply convex regularization techniques to the problem of calibrating the
local volatility surface model of Dupire taking into account the practical
requirement of discrete grids and noisy data. Such requirements are the
consequence of bid and ask spreads, quantization of the quoted prices and lack
of liquidity of option prices for strikes far way from the at the money level.
  We obtain convergence rates and results comparable to those obtained in the
idealized continuous setting. Our results allow us to take into account
separately the uncertainties due to the price noise and those due to
discretization errors. Thus allowing better discretization levels both in the
domain and in the image of the parameter to solution operator.
  We illustrate the results with simulated as well as real market data. We also
validate the results by comparing the implied volatility prices of market data
with the computed prices of the calibrated model. {10pt}
  \noindent {\bf Keywords:} Convex regularization, local volatility surfaces,
regularization convergence rates, numerical methods for volatility calibration.


title: Chiral condensate at finite density using chiral Ward identity

abstract:
  In order to study partial restoration of the chiral symmetry at finite
density, we investigate the density corrections of the chiral condensate up to
next-leading order of density expansion using the chiral Ward identity and an
in-medium chiral perturbation theory. In our study, we assume that all the
in-vacuum quantities for the pion, the nucleon and the pi N interaction are
determined and focus on density expansion of the in-medium physical quantities.
We perform diagrammatic analysis of the correlation functions which provide the
in-medium chiral condensate. This density expansion scheme shows that medium
effects to the chiral condensate beyond the linear density come from density
corrections to the pi N sigma term as a result of the interactions between pion
and nucleon in nuclear matter. We also discuss that higher density
contributions beyond order of rho^2 cannot be fixed only by the in-vacuum pi N
dynamics but we need NN two-body dynamics in vacuum to fix divergence appearing
in the calculation of the rho^2 dependence of the chiral condensate with the pi
N dynamics.


title:
The clustering of ALFALFA galaxies: dependence on HI mass, relationship
  to optical samples & clues on host halo properties

abstract:
  We use a sample of ~6000 galaxies detected by the Arecibo Legacy Fast ALFA
(ALFALFA) 21cm survey, to measure the clustering properties of HI-selected
galaxies. We find no convincing evidence for a dependence of clustering on the
galactic atomic hydrogen (HI) mass, over the range M_HI ~ 10^{8.5} - 10^{10.5}
M_sun. We show that previously reported results of weaker clustering for low-HI
mass galaxies are probably due to finite-volume effects. In addition, we
compare the clustering of ALFALFA galaxies with optically selected samples
drawn from the Sloan Digital Sky Survey (SDSS). We find that HI-selected
galaxies cluster more weakly than even relatively optically faint galaxies,
when no color selection is applied. Conversely, when SDSS galaxies are split
based on their color, we find that the correlation function of blue optical
galaxies is practically indistinguishable from that of HI-selected galaxies. At
the same time, SDSS galaxies with red colors are found to cluster significantly
more than HI-selected galaxies, a fact that is evident in both the projected as
well as the full two-dimensional correlation function. A cross-correlation
analysis further reveals that gas-rich galaxies "avoid" being located within ~3
Mpc of optical galaxies with red colors. Next, we consider the clustering
properties of halo samples selected from the Bolshoi LambdaCDM simulation. A
comparison with the clustering of ALFALFA galaxies suggests that galactic HI
mass is not tightly related to host halo mass, and that a sizable fraction of
subhalos do not host HI galaxies. Lastly, we find that we can recover fairly
well the correlation function of HI galaxies by just excluding halos with low
spin parameter. This finding lends support to the hypothesis that halo spin
plays a key role in determining the gas content of galaxies.


title:
A Rolle type theorem for cyclicity of zeros of families of analytic
  functions

abstract:
  Let $\{f_{\lambda; j}\}_{\lambda\in V; 1\le j\le k}$ be families of
holomorphic functions in the open unit disk $\Di\subset\Co$ depending
holomorphically on a parameter $\lambda\in V\subset \Co^n$. We establish a
Rolle type theorem for the generalized multiplicity (called {\em cyclicity}) of
zero of the family of univariate holomorphic functions ${\sum_{j=1}^k
f_{\lambda;j}}_{\lambda\in V}$ at $0\in\Di$. As a corollary, we estimate the
cyclicity of the family of generalized exponential polynomials, that is, the
family of entire functions of the form $\sum_{k=1}^m P_k(z)e^{Q_k(z)}$,
$z\in\Co$, where $P_k$ and $Q_k$ are holomorphic polynomials of degrees $p$ and
$q$, respectively, parameterized by vectors of coefficients of $P_k$ and $Q_k$.


title:
The regularization and determination of the Yang-Mills vacuum wave
  functional in three dimensions at O(e^2)

abstract:
  We complete the computation of the Yang-Mills vacuum wave functional in three
dimensions at weak coupling with O(e^2) precision. We use two different methods
to solve the functional Schroedinger equation. One of them generalizes to
O(e^2) the method followed by Hatfield at O(e). The other uses the weak
coupling version of the gauge invariant formulation of the Schroedinger
equation and the ground state wave functional followed by Karabali, Nair, and
Yelnikov. These methods need to be carefully regularized to yield correct
results. This is done in this paper with full detail.


title: Current Densities in Density Functional Theory

abstract:
  It is well known that any given density rho(x)can be realized by a
determinantal wave function for N particles. The question addressed here is
whether any given density rho(x) and current density j(x) can be simultaneously
realized by a (finite kinetic energy) determinantal wave function. In case the
velocity field v(x) =j(x)/rho(x) is curl free, we provide a solution for all N,
and we provide an explicit upper bound for the energy. If the velocity field is
not curl free, there is a finite energy solution for all N\geq 4, but we do not
provide an explicit energy bound in this case. For N=2 we provide an example of
a non curl free velocity field for which there is a solution, and an example
for which there is no solution. The case $N=3 with a non curl free velocity
field is left open.

categories: physics.chem-ph cond-mat.str-el math-ph math.MP


title: Firewalls From Double Purity

abstract:
  The firewall paradox is often presented as arising from double entanglement,
but I argue that more generally the paradox is double purity. Near-horizon
modes are purified by the interior, in the infalling vacuum. Hence they cannot
also be pure alone, or in combination with any third system, as demanded by
unitarity. This conflict arises independently of the Page time, for entangled
and for pure states. It implies that identifications of Hilbert spaces cannot
resolve the paradox.
  Traditional complementarity requires the unitary identification of infalling
matter with a scrambled subsystem of the Hawking radiation. Extending this map
to the infalling vacuum overdetermines the out-state. More general
complementarity maps ("A=R_B", "ER=EPR") founder when the near-horizon zone is
pure. I argue that pure-zone states span the microcanonical ensemble, and that
this suffices to make the horizon a special place.
  I advocate that the ability to detect the horizon locally, rather than the
degree or probability of violence, is what makes firewalls problematic.
Conversely, if the production of matter at the horizon can be dynamically
understood and shown to be consistent, then firewalls do not constitute a
violation of the equivalence principle.


title: Combinatorially interpreting generalized Stirling numbers

abstract:
  Let $w$ be a word in alphabet $\{x,D\}$ with $m$ $x$'s and $n$ $D$'s.
Interpreting "$x$" as multiplication by $x$, and "$D$" as differentiation with
respect to $x$, the identity $wf(x) = x^{m-n}\sum_k S_w(k) x^k D^k f(x)$, valid
for any smooth function $f(x)$, defines a sequence $(S_w(k))_k$, the terms of
which we refer to as the {\em Stirling numbers (of the second kind)} of $w$.
The nomenclature comes from the fact that when $w=(xD)^n$, we have $S_w(k)={n
\brace k}$, the ordinary Stirling number of the second kind.
  Explicit expressions for, and identities satisfied by, the $S_w(k)$ have been
obtained by numerous authors, and combinatorial interpretations have been
presented. Here we provide a new combinatorial interpretation that retains the
spirit of the familiar interpretation of ${n \brace k}$ as a count of
partitions. Specifically, we associate to each $w$ a quasi-threshold graph
$G_w$, and we show that $S_w(k)$ enumerates partitions of the vertex set of
$G_w$ into classes that do not span an edge of $G_w$. We also discuss some
relatives of, and consequences of, our interpretation, including $q$-analogs
and bijections between families of labelled forests and sets of restricted
partitions.


title:
Some Paranormed Difference Sequence Spaces of Order $m$ Derived by
  Generalized Means and Compact Operators

abstract:
  We have introduced a new sequence space $l(r, s, t, p ;\Delta^{(m)})$
combining by using generalized means and difference operator of order $m$. We
have shown that the space $l(r, s, t, p ;\Delta^{(m)})$ is complete under some
suitable paranorm and it has Schauder basis. Furthermore, the $\alpha$-,
$\beta$-, $\gamma$- duals of this space is computed and also obtained necessary
and sufficient conditions for some matrix transformations from $l(r, s, t, p;
\Delta^{(m)})$ to $l_{\infty}, l_1$. Finally, we obtained some identities or
estimates for the operator norms and the Hausdorff measure of noncompactness of
some matrix operators on the BK space $l_{p}(r, s, t ;\Delta^{(m)})$ by
applying the Hausdorff measure of noncompactness.


title:
Friedmann equations in braneworld scenarios from emergence of cosmic
  space

abstract:
  Recently, it was argued that the spacetime dynamics can be understood by
calculating the difference between the degrees of freedom on the boundary and
in the bulk in a region of space. In this Letter, we apply this new idea to
braneworld scenarios and extract the corresponding Friedmann equations of
$(n-1)$-dimensional brane embedded in the $(n+1)$-dimensional bulk with any
spacial curvature. We will also extend our study to the more general
Gauss-Bonnet braneworld with curvature correction terms on the brane and in the
bulk, and derive the dynamical equation in a nonflat Universe.


title: The AGORA High-Resolution Galaxy Simulations Comparison Project

abstract:
  We introduce the AGORA project, a comprehensive numerical study of
well-resolved galaxies within the LCDM cosmology. Cosmological hydrodynamic
simulations with force resolutions of ~100 proper pc or better will be run with
a variety of code platforms to follow the hierarchical growth, star formation
history, morphological transformation, and the cycle of baryons in and out of 8
galaxies with halo masses M_vir ~= 1e10, 1e11, 1e12, and 1e13 Msun at z=0 and
two different ("violent" and "quiescent") assembly histories. The numerical
techniques and implementations used in this project include the smoothed
particle hydrodynamics codes GADGET and GASOLINE, and the adaptive mesh
refinement codes ART, ENZO, and RAMSES. The codes will share common initial
conditions and common astrophysics packages including UV background,
metal-dependent radiative cooling, metal and energy yields of supernovae, and
stellar initial mass function. These are described in detail in the present
paper. Subgrid star formation and feedback prescriptions will be tuned to
provide a realistic interstellar and circumgalactic medium using a
non-cosmological disk galaxy simulation. Cosmological runs will be
systematically compared with each other using a common analysis toolkit, and
validated against observations to verify that the solutions are robust - i.e.,
that the astrophysical assumptions are responsible for any success, rather than
artifacts of particular implementations. The goals of the AGORA project are,
broadly speaking, to raise the realism and predictive power of galaxy
simulations and the understanding of the feedback processes that regulate
galaxy "metabolism." The proof-of-concept dark matter-only test of the
formation of a galactic halo with a z=0 mass of M_vir ~= 1.7e11 Msun by 9
different versions of the participating codes is also presented to validate the
infrastructure of the project.


title: Spitzer, Gaia, and the Potential of the Milky Way

abstract:
  Near-future data from ESA's Gaia mission will provide precise, full
phase-space information for hundreds of millions of stars out to heliocentric
distances of ~10 kpc. This "horizon" for full phase-space measurements is
imposed by the Gaia parallax errors degrading to worse than 10%, and could be
significantly extended by an accurate distance indicator. Recent work has
demonstrated how Spitzer observations of RR Lyrae stars can be used to make
distance estimates accurate to 2%, effectively extending the Gaia, precise-data
horizon by a factor of ten in distance and a factor of 1000 in volume. This
Letter presents one approach to exploit data of such accuracy to measure the
Galactic potential using small samples of stars associated with debris from
satellite destruction. The method is tested with synthetic observations of 100
stars from the end point of a simulation of satellite destruction: the shape,
orientation, and depth of the potential used in the simulation are recovered to
within a few percent. The success of this simple test with such a small sample
in a single debris stream suggests that constraints from multiple streams could
be combined to examine the Galaxy's dark matter halo in even more detail --- a
truly unique opportunity that is enabled by the combination of Spitzer and Gaia
with our intimate perspective on the Galaxy.


title:
A variation of the fraction of stars that form in bound clusters within
  M83

abstract:
  Recent observations, as well as theoretical studies, have suggested that
stellar cluster formation may depend on local and global environmental
properties. In particular, the fraction of stars that form within long-lived
bound clusters (\Gamma) may depend on environment, with indications that it may
be higher in the more extreme environments of high star-formation rate density
galaxies. How \Gamma varies has important implications on the use of clusters
to determine the star-formation histories of galaxies as well as our
understanding of the star-formation process itself. Previous studies have
estimated \Gamma over full galaxies, making it difficult to discern the
physical cause of the reported variations. Here, we use existing star cluster
catalogues and HST-WFC3 V and I images of the grand design, face-on spiral
galaxy M83 in order to see if and how \Gamma varies within a single galaxy. We
find that \Gamma decreases strongly as a function of galactocentric radius, by
a factor of ~5 over the inner ~6kpc, in agreement with recent theoretical
predictions and decreasing trends observed in the gas surface density of the
galaxy.


title: Kerr-AdS analogue of triple point and solid/liquid/gas phase transition

abstract:
  We study the thermodynamic behavior of multi-spinning d=6 Kerr-anti de Sitter
black holes in the canonical ensemble of fixed angular momenta J1 and J2. We
find, dependent on the ratio q=J2/J1, qualitatively different interesting
phenomena known from the `every day thermodynamics' of simple substances. For
q=0 the system exhibits recently observed reentrant large/small/large black
hole phase transitions, but for 0<q<<1 we find an analogue of a `solid/liquid'
phase transition. Furthermore, for 0.00905<q<0.0985 the system displays the
presence of a large/intermediate/small black hole phase transition with one
tricritical and two critical points. This behavior is reminiscent of the
solid/liquid/gas phase transition except that the coexistence line of small and
intermediate black holes does not continue for an arbitrary value of pressure
(similar to the solid/liquid coexistence line) but rather terminates at one of
the critical points. Finally, for q>0.0985 we observe the `standard liquid/gas
behavior' of the Van der Waals fluid.


title:
Independent constraints on local non-Gaussianity from the peculiar
  velocity and density fields

abstract:
  Primordial, non-Gaussian perturbations can generate scale-dependent bias in
the galaxy distribution. This in turn will modify correlations between galaxy
positions and peculiar velocities at late times, since peculiar velocities
reflect the underlying matter distribution, whereas galaxies are a biased
tracer of the same. We study this effect, and show that non-Gaussianity can be
constrained by comparing the observed peculiar velocity field to a model
velocity field reconstructed from the galaxy density field assuming linear
bias. The amplitude of the spatial correlations in the residual map obtained
after subtracting one velocity field from the other is directly proportional to
the strength of the primordial non-Gaussianity. We construct the corresponding
likelihood function use it to constrain the amplitude of the linear flow
$\beta$ and the amplitude of local non-Gaussianity $f^{\rm NL}_{\rm local}$.
Applying our method to two observational data sets, the Type-Ia supernovae
(A1SN) and Spiral Field \textit{I}-band (SFI++) catalogues, we obtain
constraints on the linear flow parameter consistent with the values derived
previously assuming Gaussianity. The marginalised 1-D distribution of $|f^{\rm
NL}_{\rm local}|$ does not show strong evidence for non-zero $f^{\rm NL}_{\rm
local}$, and we set 95% upper limits $|f^{\rm NL}_{\rm local}|<51.4$ from A1SN
and $|f^{\rm NL}_{\rm local}|<92.6$ from SFI++. These limits on $f^{\rm
NL}_{\rm local}$ are as tight as any set by previous large-scale structure
measurements. Our method can be applied to any survey with radial velocities
and density field data, and provides an independent check of recent CMB
constraints on $f^{\rm NL}_{\rm local}$, extending these to smaller spatial
scales.


title: Higgs CP properties using the tau decay modes at the ILC

abstract:
  We investigate the prospects of determining the CP nature of the 126 GeV
neutral spin-0 (Higgs) boson h, discovered at the LHC, at a future linear
collider. We consider the production of h by the Higgsstrahlung process and its
subsequent decays to tau leptons. We investigate how precisely a possible
pseudoscalar component of h can be detected by the measurement of a suitably
defined angular distribution, if all major decay modes of the tau lepton are
used. From our numerical simulations, we estimate the expected precision to the
scalar-pseudoscalar mixing angle, including estimates of the background and of
measurement uncertainties, to be 2.8 degree for Higgs-boson production at a
center-of-mass energy of 250 GeV and for a collider with integrated luminosity
of 1 inverse attobarn.


title: Comparison of sampling techniques for Bayesian parameter estimation

abstract:
  The posterior probability distribution for a set of model parameters encodes
all that the data have to tell us in the context of a given model; it is the
fundamental quantity for Bayesian parameter estimation. In order to infer the
posterior probability distribution we have to decide how to explore parameter
space. Here we compare three prescriptions for how parameter space is
navigated, discussing their relative merits. We consider Metropolis-Hasting
sampling, nested sampling and affine-invariant ensemble MCMC sampling. We focus
on their performance on toy-model Gaussian likelihoods and on a real-world
cosmological data set. We outline the sampling algorithms themselves and
elaborate on performance diagnostics such as convergence time, scope for
parallelisation, dimensional scaling, requisite tunings and suitability for
non-Gaussian distributions. We find that nested sampling delivers high-fidelity
estimates for posterior statistics at low computational cost, and should be
adopted in favour of Metropolis-Hastings in many cases. Affine-invariant MCMC
is competitive when computing clusters can be utilised for massive
parallelisation. Affine-invariant MCMC and existing extensions to nested
sampling naturally probe multi-modal and curving distributions.