title: Upper bounds for the Euclidean minima of abelian number fields

abstract:
  The aim of this paper is to survey and extend results concerning bounds of
the Euclidean minima of abelian number fields. In particular, we give upper
bounds for the Euclidean minima of abelian number fields of prime power
conductor.


title:
The curious time lags of PG 1244+026: Discovery of the iron K
  reverberation lag

abstract:
  High-frequency iron K reverberation lags, where the red wing of the line
responds before the line centroid, are a robust signature of relativistic
reflection off the inner accretion disc. In this letter, we report the
discovery of the Fe K lag in PG 1244+026 from ~120 ks of data (1 orbit of the
XMM-Newton telescope). The amplitude of the lag with respect to the continuum
is 1000 s at a frequency of ~1e-4 Hz. We also find a possible
frequency-dependence of the line: as we probe higher frequencies (i.e. shorter
timescales from a smaller emitting region) the Fe K lag peaks at the red wing
of the line, while at lower frequencies (from a larger emitting region) we see
the dominant reflection lag from the rest frame line centroid. The mean energy
spectrum shows a strong soft excess, though interestingly, there is no
indication of a soft lag. Given that this source has radio emission and it has
little reported correlated variability between the soft excess and the hard
band, we explore one possible explanation in which the soft excess in this
source is dominated by the steep power-law like emission from a jet, and that a
corona (or base of the jet) irradiates the inner accretion disc, creating the
blurred reflection features evident in the spectrum and the lag. General
Relativistic ray-tracing models fit the Fe K lag well, with the best-fit giving
a compact X-ray source at a height of 5 gravitational radii and a black hole
mass of 1.3e7 Msun.


title: X-ray time delays in the Narrow Line Seyfert 1 galaxy PG 1244+026

abstract:
  We analyse the X-ray time-lags in the Narrow Line Seyfert 1 (NLS1) galaxy PG
1244+026 ($M_{\rm BH}\sim 10^7 M_{\rm sun}$, $L/L_{\rm Edd}\sim 1$). The time
delay between the soft (0.3--0.7~keV) and harder (1.2--4.0~keV) variations
shows shows the well established switch from hard lags at low frequencies to
soft lags at high frequencies. The low frequency hard lags are qualitatively
consistent with the propagation of fluctuations model, with some long-timescale
response of the reflection component. The high frequency soft lag appears to
extend over a wide frequency band, that we divide this into two narrow
frequency ranges, and examine the lag as a function of energy for each of
these. At high frequencies the soft excess emission is delayed with respect to
the harder energy bands, without any corresponding strong, hard X-ray
reflection signature. At even higher frequencies a soft lag is seen at the
softest energies, as well as tentative evidence for an iron K$\alpha$
reverberation signal. These results point to the importance of reprocessing as
well as reflection in determining the lags in NLS1s.


title:
Size distribution of supernova remnants and the interstellar medium: the
  case of M33

abstract:
  The size distribution of supernova remnants (SNRs) can help to clarify the
various aspects of their evolution and interaction with the interstellar medium
(ISM). Since the observed samples of SNRs are a collection of objects with very
different ages and origin that evolve in different conditions of the ISM,
statistical Monte Carlo methods can be used to model their statistical
distributions. Based on very general assumptions on the evolution, we have
modeled samples of SNRs at various initial and environmental conditions, which
were then compared with observed collections of SNRs. In the evolution of SNRs
the pressure of the ISM is taken into account, which determines their maximum
sizes and lifetimes. When comparing the modeled and observed distributions, it
is very important to have homogeneous observational data free from selection
effects. We found that a recently published collection of SNRs in M33 (Long et
al. 2010, ApJS,187,495) satisfies this requirement if we select the X-ray SNRs
with hardness ratios in a limited range of values. An excellent agreement
between distributions of this subset of SNRs and the subset of modeled SNRs was
reached for a volume filling-factor of the warm phase of the ISM (partly
ionized gas with $n_{\rm H}\sim 0.2-0.5~ \rm {cm}^{-3}; T \sim 8000-10000~K $)
in M33 of $\sim\ 90%$. The statistical distributions constructed in this way,
which reproduce practically all the statistical properties of observed SNRs,
allowed us to obtain one of the important parameters of M33: the birthrate is
one SNR every $ {140} - {150}$ yr, and the total number of SNRs with a shock
Mach number $M_{s} \geq 2$ is larger than $\sim 1000$.


title: The Cauchy Integral in $\mathbb C^n$ for domains with minimal smoothness

abstract:
  We prove $L^p(b\mathcal{D})$-regularity of the Cauchy-Leray integral for
bounded domains $\mathcal{D}\subset\mathbb C^n$ whose boundary satisfies the
minimal regularity condition of class $C^{1,1}$, together with a naturally
occurring notion of convexity.


title:
Boltzmann equation for granular media with thermal force in a weakly
  inhomogeneous setting

abstract:
  In this paper, we consider the spatially inhomogeneous diffusively driven
inelastic Boltzmann equation in different cases: the restitution coefficient
can be constant or can depend on the impact velocity (which is a more
physically relevant case), including in particular the case of viscoelastic
hard spheres. In the weak thermalization regime, i.e. when the diffusion
parameter is sufficiently small, we prove existence of global solutions
considering the close-to-equilibrium regime as well as the weakly inhomogeneous
regime in the case of a constant restitution coefficient. It is the very first
existence theorem of global solution in an inelastic "collision regime" (that
is excluding \cite{AR} where an existence theorem is proven in a near to the
vacuum regime). We also study the long-time behavior of these solutions and
prove a convergence to equilibrium with an exponential rate. The basis of the
proof is the study of the linearized equation. We obtain a new result on it, we
prove existence of a spectral gap in weighted (stretched exponential and
polynomial) Sobolev spaces and a result of exponential stability for the
semigroup generated by the linearized operator. To do that, we develop a
perturbative argument around the spatially inhomogeneous equation for elastic
hard spheres and we take advantage of the recent paper \cite{GMM}where this
equation has been considered. We then link the linearized theory with the
nonlinear one in order to handle the full non-linear problem thanks to new
bilinear estimates on the collision operator that we establish. As far as the
case of a constant coefficient is concerned, the present paper largely improves
similar results obtained in \cite{MM2} in a spatially homogeneous framework.
Concerning the case of a non-constant coefficient, this kind of results is new
and we use results on steady states of the linearized equation from \cite{AL3}.


title: Recovering functions from the Paley-Wiener amalgam space

abstract:
  In this paper we show that functions from the Paley-Wiener amalgam space
$(PW,l^1)=\{f\in L^2(\mathbb{R}): \sum\|\hat{f}(\xi+2\pi m)
\|_{L^2([-\pi,\pi])} < \infty\}$ enjoy similar recovery properties as the
classical Paley-Wiener space. Specifically, if $\{\phi_\alpha(x): \alpha\in
A\}$ is a regular family of interpolators and $\{x_n: n\in \mathbb{Z}\}$ is a
complete interpolating sequence for $L^2([-\pi,\pi])$, then the family $\{
e^{2\pi i m x}\phi_{\alpha}(x-x_n): m,n\in \mathbb{Z}, \alpha\in A \} $ may be
used to recover $f\in(PW,l^1)$.


title: On permanent and breaking waves in hyperelastic rods and rings

abstract:
  We prove that the only global strong solution of the periodic rod equation
vanishing in at least one point $(t_0,x_0)$ is the identically zero solution.
Such conclusion holds provided the physical parameter $\gamma$ of the model
(related to the finger deformation tensor) is outside some neighborhood of the
origin and applies in particular for the Camassa--Holm equation, corresponding
to $\gamma=1$. We also establish the analogue of this unique continuation
result in the case of non-periodic solutions defined on the whole real line
with vanishing boundary conditions at infinity. Our analysis relies on the
application of new local-in-space blowup criteria and involves the computation
of several best constants in convolution estimates and weighted Poincar\'e
inequalities.


title:
Accumulation points of the sets of real parts of zeros of the partial
  sums of the Riemann zeta function

abstract:
  It is shown that, for every integer n>2, there exists \delta_{n}>0 such that
the closure of the set of the real parts of the zeros of the nth partial sum of
the Riemann zeta function \zeta_{n} contains to the interval
[-\delta_{n},b^{n}]. b^{n} is the supremum of the real parts of the zeros of
\zeta_{n}. It is also demonstrated that b^{n} is positive for all n>2. It is
also shown that 0 is an accumulation point common to all the sets P_{\zeta_{n}}
wich are the sets of the real parts of the zeros of \zeta_{n}.


title: Numerical modeling of ion transport in a ESI-MS system

abstract:
  Gas and ion transport in the capillary-skimmer subatmospheric interface of a
mass spectrometer, which is typically utilized to separate unevaporated
micro-droplets from ions, was studied numerically using a two-step approach
spanning multiple gas dynamic regimes. The gas flow in the heated capillary and
in the interface was determined by solving numerically the Navier-Stokes
equation. The capillary-to-skimmer gas/ion flow was modeled through the
solution of the full Boltzmann equation with a force term. The force term,
together with calculated aerodynamic drag, determined the ion motion in the gap
between the capillary and skimmer. The three-dimensional modeling of the impact
of the voltage applied to the Einzel lens on the transmission of doubly-charged
peptides ions through the skimmer orifice was compared with experimental data
obtained in the companion study. Good agreement between measured and computed
signals was observed. The numerical results indicate that as many as 75% ions
that exit from the capillary can be lost on the conical surface of the skimmer
or capillary outer surface due to the electrostatic force and plume divergence.


title: Signed Mahonian polynomials for major and sorting indices

abstract:
  We derive some new signed Mahonian polynomials over the complex reflection
group $G(r,1,n)=C_r\wr\mathfrak{S}_n$, where the "sign" is taken to be any of
the $2r$ $1$-dim characters and the "Mahonian" statistics are the
$\mathsf{lmaj}$ defined by Bagno and the $\mathsf{sor}$ defined by Eu et al.
Various new signed Mahonian polynomials over Coxeter groups of types $B_n$ and
$D_n$ are derived as well. We also investigate the signed counting polynomials
on $G(r,1,n)$ for those statistics with the distribution $[r]_q[2r]_q\cdots
[nr]_q$.


title:
Direct Observation of Fragmentation in a Disordered, Strongly
  Interacting Fermi Gas

abstract:
  Describing the behaviour of strongly interacting particles in the presence of
disorder is among the most challenging problems in quantum many-body physics.
The controlled setting of cold atom experiments provides a new avenue to
address these challenges [1], complementing studies in solid state physics,
where a number of puzzling findings have emerged in experiments using
superconducting thin films [2,3]. Here we investigate a strongly interacting
thin film of an atomic Fermi gas subject to a random potential. We use
high-resolution in-situ imaging [4-7] to resolve the atomic density at the
length scale of a single impurity, which would require scanning probe
techniques in solid state physics [8]. This allows us to directly observe the
fragmentation of the density profile and to extract its percolation properties.
Transport measurements in a two-terminal configuration indicate that the
fragmentation process is accompanied by a breakdown of superfluidity. Our
results suggest that percolation of paired atoms is responsible for the loss of
superfluidity, and that disorder is able to increase the binding energy of
pairs.


title: Cauchy-type integrals in several complex variables

abstract:
  We present the theory of Cauchy-Fantappi\'e integral operators, with emphasis
on the situation when the domain of integration, $D$, has minimal boundary
regularity. Among these operators we focus on those that are more closely
related to the classical Cauchy integral for a planar domain, whose kernel is a
holomorphic function of the parameter $z\in D$. The goal is to prove $L^p$
estimates for these operators and, as a consequence, to obtain $L^p$ estimates
for the canonical Cauchy-Szeg\"o and Bergman projection operators (which are
not of Cauchy-Fantappi\'e type).


title:
Bending rigidity and higher order curvature terms for the hard-sphere
  fluid near a curved wall

abstract:
  In this work I derive analytic expressions for the curvature dependent
fluid-substrate surface tension of a hard sphere fluid on a hard curved wall.
In a first step, the curvature thermodynamic properties are found as truncated
power series in the activity in terms of the known second and third order
cluster integral of the hard-sphere fluid near spherical and cylindrical walls.
These results are then expressed as packing fraction power series and
transformed to different reference regions which is equivalent to consider
different positions of the dividing surface. All the obtained series expansions
are rigorous results. Based on the truncated series it is shown that the
bending rigidity of the system is non-null and that higher order terms in the
curvature also exist. In a second step, approximate analytic expressions for
the surface tension, the Tolman length, the bending rigidity and the Gaussian
rigidity as functions of the packing fraction are found by considering the
known terms of the series expansion complemented with a simple fitting
approach. It is found that the obtained formulas accurately describe the
curvature thermodynamic properties of the system, further, they are more
accurate than any of the previously published expressions.


title:
Renormalization of HQET $\Delta B=2$ operators: O($a$) improvement and
  $1/m$ matching with QCD

abstract:
  We determine a basis of dimension-7 operators which arise at O($a$) in the
Symanzik expansion of the $\Delta B=2$ operators with static heavy quarks. We
consider both Wilson-like and Ginsparg-Wilson light quarks. Exact chiral
symmetry reduces the number of these O($a$) counterterms by a factor of two.
Only a subset of these operators has previously appeared in the literature. We
then extend the analysis to the O($1/m$) operators contributing beyond the
static approximation.


title: Higher order analogues of exterior derivative

abstract:
  We give new examples of linear differential operators of order $k=2m+1$ (any
given odd integer) that are invariant under the isometries of $\mathbb R^n$ and
satisfy so-called $L^1$-duality estimates and div/curl inequalities.


title: Sparse PCA via Covariance Thresholding

abstract:
  In sparse principal component analysis we are given noisy observations of a
low-rank matrix of dimension $n\times p$ and seek to reconstruct it under
additional sparsity assumptions. In particular, we assume here each of the
principal components $\mathbf{v}_1,\dots,\mathbf{v}_r$ has at most $s_0$
non-zero entries. We are particularly interested in the high dimensional regime
wherein $p$ is comparable to, or even much larger than $n$. In an influential
paper, \cite{johnstone2004sparse} introduced a simple algorithm that estimates
the support of the principal vectors $\mathbf{v}_1,\dots,\mathbf{v}_r$ by the
largest entries in the diagonal of the empirical covariance. This method can be
shown to identify the correct support with high probability if $s_0\le
K_1\sqrt{n/\log p}$, and to fail with high probability if $s_0\ge K_2
\sqrt{n/\log p}$ for two constants $0<K_1,K_2<\infty$. Despite a considerable
amount of work over the last ten years, no practical algorithm exists with
provably better support recovery guarantees.
  Here we analyze a covariance thresholding algorithm that was recently
proposed by \cite{KrauthgamerSPCA}. On the basis of numerical simulations (for
the rank-one case), these authors conjectured that covariance thresholding
correctly recover the support with high probability for $s_0\le K\sqrt{n}$
(assuming $n$ of the same order as $p$). We prove this conjecture, and in fact
establish a more general guarantee including higher-rank as well as $n$ much
smaller than $p$. Recent lower bounds \cite{berthet2013computational,
ma2015sum} suggest that no polynomial time algorithm can do significantly
better. The key technical component of our analysis develops new bounds on the
norm of kernel random matrices, in regimes that were not considered before.


title: The mixed $L_p$ geominimal surface areas for multiple convex bodies

abstract:
  In this paper, we introduce several mixed $L_p$ geominimal surface areas for
multiple convex bodies for all $p\neq -n$. Our definitions are motivated from
an equivalent formula for the mixed $p$-affine surface area. Some properties,
such as the affine invariance, for these mixed $L_p$ geominimal surface areas
are proved. Related inequalities, such as, Alexander-Fenchel type inequality,
Santal\'{o} style inequality, affine isoperimetric inequalities, and cyclic
inequalities are established. Moreover, we also study some properties and
inequalities for the $i$-th mixed $L_p$ geominimal surface areas for two convex
bodies.


title: On the quality of complementary bounds for eigenvalues

abstract:
  A concrete formulation of the Lehmann-Maehly-Goerisch method for
semi-definite self-adjoint operators with compact resolvent is considered.
Precise rates of convergence are determined in terms of how well the trial
spaces capture the spectral subspace of the operator. Optimality of the choice
of a shift parameter which is intrinsic to the method is also examined. The
main theoretical findings are illustrated by means of a few numerical
experiments involving one-dimensional Schrodinger operators.


title: Mixed mode oscillations in a conceptual climate model

abstract:
  Much work has been done on relaxation oscillations and other simple
oscillators in conceptual climate models. However, the oscillatory patterns in
climate data are often more complicated than what can be described by such
mechanisms. This paper examines complex oscillatory behavior in climate data
through the lens of mixed-mode oscillations. As a case study, a conceptual
climate model with governing equations for global mean temperature, atmospheric
carbon, and oceanic carbon is analyzed. The nondimensionalized model is a
fast/slow system with one fast variable (corresponding to ice volume) and two
slow variables (corresponding to the two carbon stores). Geometric singular
perturbation theory is used to demonstrate the existence of a folded node
singularity. A parameter regime is found in which (singular) trajectories that
pass through the folded node are returned to the singular funnel in the
limiting case where $\epsilon = 0$. In this parameter regime, the model has a
stable periodic orbit of type $1^s$ for some $s>0$. To our knowledge, it is the
first conceptual climate model demonstrated to have the capability to produce
an MMO pattern.


title: Hecke Operators on Stable Cohomology

abstract:
  We prove that the completed cohomology groups of SL_N(Z) in fixed degree
stabilize as N goes to infinity. We also prove that the action of Hecke
operators on stable cohomology is trivial, in a precisely defined sense.


title:
Spectrum-Sharing Multi-Hop Cooperative Relaying: Performance Analysis
  Using Extreme Value Theory

abstract:
  In spectrum-sharing cognitive radio systems, the transmit power of secondary
users has to be very low due to the restrictions on the tolerable interference
power dictated by primary users. In order to extend the coverage area of
secondary transmission and reduce the corresponding interference region,
multi-hop amplify-and-forward (AF) relaying can be implemented for the
communication between secondary transmitters and receivers. This paper
addresses the fundamental limits of this promising technique. Specifically, the
effect of major system parameters on the performance of spectrum-sharing
multi-hop AF relaying is investigated. To this end, the optimal transmit power
allocation at each node along the multi-hop link is firstly addressed. Then,
the extreme value theory is exploited to study the limiting distribution
functions of the lower and upper bounds on the end-to-end signal-to-noise ratio
of the relaying path. Our results disclose that the diversity gain of the
multi-hop link is always unity, regardless of the number of relaying hops. On
the other hand, the coding gain is proportional to the water level of the
optimal water-filling power allocation at secondary transmitter and to the
large-scale path-loss ratio of the desired link to the interference link at
each hop, yet is inversely proportional to the accumulated noise, i.e. the
product of the number of relays and the noise variance, at the destination.
These important findings do not only shed light on the performance of the
secondary transmissions but also benefit system designers improving the
efficiency of future spectrum-sharing cooperative systems.


title:
Mathematical Model of a pH-gradient Creation at Isoelectrofocusing. Part
  II. Numerical Solution of the Stationary Problem

abstract:
  The mathematical model describing the natural textrm{pH}-gradient arising
under the action of an electric field in an aqueous solution of ampholytes
(amino acids) is constructed and investigated. This paper is the second part of
the series papers \cite{Part1,Part3,Part4} that are devoted to pH-gradient
creation problem. We present the numerical solution of the stationary problem.
The equations system has a small parameter at higher derivatives and the
turning points, so called stiff problem. To solve this problem numerically we
use the shooting method: transformation of the boundary value problem to the
Cauchy problem. At large voltage or electric current density we compare the
numerical solution with weak solution presented in Part 1.


title:
Information Causality, Szemer\'{e}di-Trotter and Algebraic Variants of
  CHSH

abstract:
  In this work, we consider the following family of two prover one-round games.
In the CHSH_q game, two parties are given x,y in F_q uniformly at random, and
each must produce an output a,b in F_q without communicating with the other.
The players' objective is to maximize the probability that their outputs
satisfy a+b=xy in F_q. This game was introduced by Buhrman and Massar (PRA
2005) as a large alphabet generalization of the celebrated CHSH game---which is
one of the most well-studied two-prover games in quantum information theory,
and which has a large number of applications to quantum cryptography and
quantum complexity.
  Our main contributions in this paper are the first asymptotic and explicit
bounds on the entangled and classical values of CHSH_q, and the realization of
a rather surprising connection between CHSH_q and geometric incidence theory.
On the way to these results, we also resolve a problem of Pawlowski and Winter
about pairwise independent Information Causality, which, beside being
interesting on its own, gives as an application a short proof of our upper
bound for the entangled value of CHSH_q.


title:
High finite-sample efficiency and robustness based on
  distance-constrained maximum likelihood

abstract:
  Good robust estimators can be tuned to combine a high breakdown point and a
specified asymptotic efficiency at a central model. This happens in regression
with MM- and tau-estimators among others. However, the finite-sample efficiency
of these estimators can be much lower than the asymptotic one. To overcome this
drawback, an approach is proposed for parametric models, which is based on a
distance between parameters. Given a robust estimator, the proposed one is
obtained by maximizing the likelihood under the constraint that the distance is
less than a given threshold. For the linear model with normal errors and using
the MM estimator and the distance induced by the Kullback-Leibler divergence,
simulations show that the proposed estimator attains a finite-sample efficiency
close to one, while its maximum mean squared error under pointwise outlier
contamination is smaller than that of the MM estimator. The same approach also
shows good results in the estimation of multivariate location and scatter.


title: Thermalized Vacuum and Vacuum Effects

abstract:
  Some of the well-known effects regarding the vacuum are revisited under the
formalism of the imaginary-time field theory. From these effects, they could
imply the existence of one thermal vacuum in different circumstances. The
imaginary-time hamiltonian of the vacuum is found to provide not only exact
distribution functions in the calculations of the Casimir effect and the Van
der Waals force but also cutoff functions. The thermal bath for the Unruh
effect is constructed from the imaginary-time Green function. From the field
theory in the curved space-time, field quantizations are defined according to
different vacuum states and lead to the Hawking radiation; the introduced
conformal invariance agree with the formalism of the imaginary-time field
theory. The induced Green functions in the curved space-time are in accordance
with those from the picture given from the thermal vacuum.


title: The Black Hole Interior and a Curious Sum Rule

abstract:
  We analyze the Euclidean geometry near non-extremal NS5-branes in string
theory, including regions beyond the horizon and beyond the singularity of the
black brane. The various regions have an exact description in string theory, in
terms of cigar, trumpet and negative level minimal model conformal field
theories. We study the worldsheet elliptic genera of these three superconformal
theories, and show that their sum vanishes. We speculate on the significance of
this curious sum rule for black hole physics.


title: The Stable Homology of Congruence Subgroups

abstract:
  In a previous paper, the author (together with Matthew Emerton) proved that
the completed cohomology groups of SL_N(Z) are stable in fixed degree as N goes
to infinity (Z may be replaced by the ring O_F of integers of any number
field). In this paper, we relate these completed cohomology groups to K-theory
and Galois cohomology. Various consequences include showing that Borel's stable
classes become infinitely p-divisible up the p-congruence tower if and only if
a certain p-adic zeta value is non-zero. We use our results to compute
H_2(Gamma_N(p),F_p) (for sufficiently large N) where Gamma_N(p) is the full
level-p congruence subgroup of SL_N(Z).


title: NLO QCD Production of Higgs boson plus jets with GoSam

abstract:
  After reviewing the main features of the GoSam framework for automated
one-loop calculations, we present a selection of recent phenomenological
results obtained with it. In particular, we focus on the recent calculation of
NLO QCD corrections to the production of a Higgs boson in conjunction with jets
at the LHC.


title: Canard-like phenomena in piecewise-smooth Van der Pol systems

abstract:
  We show that a nonlinear, piecewise-smooth, planar dynamical system can
exhibit canard phenomena. Canard solutions and explosion in nonlinear,
piecewise-smooth systems can be qualitatively more similar to the phenomena in
smooth systems than piecewise-linear systems, since the nonlinearity allows for
canards to transition from small cycles to canards ``with heads." The canards
are born of a bifurcation that occurs as the slow-nullcline coincides with the
splitting manifold. However, there are conditions under which this bifurcation
leads to a phenomenon called super-explosion, the instantaneous transition from
a globally attracting periodic orbit to relaxations oscillations. Also, we
demonstrate that the bifurcation---whether leading to canards or
super-explosion---can be subcritical.


title: Influence Diffusion in Social Networks under Time Window Constraints

abstract:
  We study a combinatorial model of the spread of influence in networks that
generalizes existing schemata recently proposed in the literature. In our
model, agents change behaviors/opinions on the basis of information collected
from their neighbors in a time interval of bounded size whereas agents are
assumed to have unbounded memory in previously studied scenarios. In our
mathematical framework, one is given a network $G=(V,E)$, an integer value
$t(v)$ for each node $v\in V$, and a time window size $\lambda$. The goal is to
determine a small set of nodes (target set) that influences the whole graph.
The spread of influence proceeds in rounds as follows: initially all nodes in
the target set are influenced; subsequently, in each round, any uninfluenced
node $v$ becomes influenced if the number of its neighbors that have been
influenced in the previous $\lambda$ rounds is greater than or equal to $t(v)$.
We prove that the problem of finding a minimum cardinality target set that
influences the whole network $G$ is hard to approximate within a
polylogarithmic factor. On the positive side, we design exact polynomial time
algorithms for paths, rings, trees, and complete graphs.


title:
Comments on non-commuting variables, n-ary algebras, and first-order
  differential equations

abstract:
  Use of certain non-commuting variables is considered in first-order
differential equations. Superspace variables are discussed within the setting
of first-order ordinary differential equations and n-ary algebras. Results on
quadratic systems based on non-associative algebras are presented. A system
related to a Li\'enard system associated to an Abel's differential equation of
the second kind is given as an example.


title: On transfer of biholomorphisms across nonminimal loci

abstract:
  A connected real analytic hypersurface M in C^(n+1) whose Levi form is
nondegenerate in at least one point - hence at every point of some Zariski-open
subset - is locally biholomorphic to the model Heisenberg quadric pseudosphere
of signature (k, n-k) in one point if and only if, at every other Levi
nondegenerate point, it is also locally biholomorphic to some Heisenberg
pseudosphere, possibly having different signature (l, n-l).


title: Finite time singularities for hyperbolic systems

abstract:
  In this paper, we study the formation of finite time singularities in the
form of super norm blowup for a spatially inhomogeneous hyperbolic system. The
system is related to the variational wave equations as those in [18]. The
system posses a unique $C^1$ solution before the emergence of vacuum in finite
time, for given initial data that are smooth enough, bounded and uniformly away
from vacuum. At the occurrence of blowup, the density becomes zero, while the
momentum stays finite, however the velocity and the energy are both infinity.


title: Approximating the Bottleneck Plane Perfect Matching of a Point Set

abstract:
  A bottleneck plane perfect matching of a set of $n$ points in $\mathbb{R}^2$
is defined to be a perfect non-crossing matching that minimizes the length of
the longest edge; the length of this longest edge is known as {\em bottleneck}.
The problem of computing a bottleneck plane perfect matching has been proved to
be NP-hard. We present an algorithm that computes a bottleneck plane matching
of size at least $\frac{n}{5}$ in $O(n \log^2 n)$-time. Then we extend our idea
toward an $O(n\log n)$-time approximation algorithm which computes a plane
matching of size at least $\frac{2n}{5}$ whose edges have length at most
$\sqrt{2}+\sqrt{3}$ times the bottleneck.


title: Simulating the Random Surface representation of Abelian Gauge Theories

abstract:
  We present a Monte-Carlo algorithm for the simulation of the all-order strong
coupling expansion of the Z2 gauge theory. This random surface ensemble is
equivalent to the standard formulation, but allows to measure some quantities,
like Polyakov loop correlators or excess free energies, with an accuracy that
could not have been easily achieved with traditional simulation methods. One
interesting application of the algorithm is the investigation of effective
string theories.


title:
Phase Transition And Hexagonal Patterns In Rich Stimulant
  Diffusion-Chemotaxis Model

abstract:
  An important component in studying mathematical models in many biochemical
systems, such as those found in developmental biology, is phase transition. The
purpose of this work is to analyze the phase transition property of a
diffusion-chemotaxis model with proliferation source, as a macroscopic model of
behavior of mobile species. Along the way, we will discuss that the system
exhibits very rich pattern-forming behavior. In particular, a portion of the
present work is devoted to the proof of existence of hexagonal patterns as a
result of instability of two Fourier modes. It is also shown that they are
either saddle points or attracting nodes. Moreover, they belong to an attractor
which consists of finite number of steady-state solutions and their connecting
heteroclinic orbits. The structure of this attractor will be precisely
determined as well.


title:
Proof of the Formula of Cachazo, He and Yuan for Yang-Mills Tree
  Amplitudes in Arbitrary Dimension

abstract:
  A proof is given of the formula, recently proposed by Cachazo, He and Yuan
(CHY) for gluon tree amplitudes in pure Yang-Mills theory in arbitrary
dimension. The approach is to first establish the corresponding result for
massless $\phi^3$ theory using the BCFW recurrence relation and then to extend
this to the gauge theory case. Additionally, it is shown that the scattering
equations introduced by CHY can be generalized to massive particles, enabling
the description of tree amplitudes for massive $\phi^3$ theory.


title:
Orientation dependence of energy absorption and relaxation dynamics of
  $\text{C}_{60}$ in fs-laser pulses: How round is $\text{C}_{60}$?

abstract:
  By means of non-adiabatic quantum molecular dynamics it is shown, that the
amount of energy deposited into $\text{C}_{60}$ by a short laser field strongly
depends on the molecular orientation with respect to the laser polarization
direction. In consequence, subsequent electron-vibration coupling leads to
different nuclear relaxation mechanisms with mainly three pathways: (1)
excitation of giant $\text{A}_g(1)$ modes ("breathing"), (2) formation of
deformed cage-like complexes ("isomers"), fragmentation predominantly into two
large pieces ("fission"). The results are in accord with and explain nicely
already existing experimental data. Future experiments are proposed to confirm
the detailed predictions.


title:
A fast directional BEM for large-scale acoustic problems based on the
  Burton-Miller formulation

abstract:
  In this paper, a highly efficient fast boundary element method (BEM) for
solving large-scale engineering acoustic problems in a broad frequency range is
developed and implemented. The acoustic problems are modeled by the
Burton-Miller boundary integral equation (BIE), thus the fictitious frequency
issue is completely avoided. The BIE is discretized by using the Nystr\"om
method based on the curved quadratic elements, leading to simple numerical
implementation (no edge or corner problems) and high accuracy in the BEM
analysis. The linear systems are solved iteratively and accelerated by using a
newly developed kernel-independent wideband fast directional algorithm (FDA)
for fast summation of oscillatory kernels. In addition, the computational
efficiency of the FDA is further promoted by exploiting the low-rank features
of the translation matrices, resulting in two- to three-fold reduction in the
computational time of the multipole-to-local translations. The high accuracy
and nearly linear computational complexity of the present method are clearly
demonstrated by typical examples. An acoustic scattering problem with
dimensionless wave number $kD$ (where $k$ is the wave number and $D$ is the
typical length of the obstacle) up to 1000 and the degrees of freedom up to 4
million is successfully solved within 10 hours on a computer with one core and
the memory usage is 24 GB.


title: Homological stability for topological chiral homology of completions

abstract:
  By proving that several new complexes of embedded disks are highly connected,
we obtain several new homological stability results. Our main result is
homological stability for topological chiral homology on an open manifold with
coefficients in certain partial framed $E_n$-algebras. Using this, we prove a
special case of a conjecture of Vakil and Wood on homological stability for
complements of closures of particular strata in the symmetric powers of an open
manifold and we prove that the bounded symmetric powers of closed manifolds
satisfy homological stability rationally.


title: On Quantifying Qualitative Geospatial Data: A Probabilistic Approach

abstract:
  Living in the era of data deluge, we have witnessed a web content explosion,
largely due to the massive availability of User-Generated Content (UGC). In
this work, we specifically consider the problem of geospatial information
extraction and representation, where one can exploit diverse sources of
information (such as image and audio data, text data, etc), going beyond
traditional volunteered geographic information. Our ambition is to include
available narrative information in an effort to better explain geospatial
relationships: with spatial reasoning being a basic form of human cognition,
narratives expressing such experiences typically contain qualitative spatial
data, i.e., spatial objects and spatial relationships.
  To this end, we formulate a quantitative approach for the representation of
qualitative spatial relations extracted from UGC in the form of texts. The
proposed method quantifies such relations based on multiple text observations.
Such observations provide distance and orientation features which are utilized
by a greedy Expectation Maximization-based (EM) algorithm to infer a
probability distribution over predefined spatial relationships; the latter
represent the quantified relationships under user-defined probabilistic
assumptions. We evaluate the applicability and quality of the proposed approach
using real UGC data originating from an actual travel blog text corpus. To
verify the quality of the result, we generate grid-based maps visualizing the
spatial extent of the various relations.


title:
High Field determination of superconducting fluctuations in high-Tc
  cuprates

abstract:
  Large pulsed magnetic fields up to 60 Tesla are used to suppress the
contribution of superconducting fluctuations (SCF) to the ab-plane conductivity
above Tc in a series of YBa2Cu3O6+x single crystals. The fluctuation
conductivity is found to vanish nearly exponentially with temperature, allowing
us to determine precisely the field H'c(T) and the temperature T'c above which
the SCFs are fully suppressed. T'c is always found much smaller than the
pseudogap temperature. A careful investigation near optimal doping shows that
T'c is higher than the pseudogap T*, which indicates that the pseudogap cannot
be assigned to preformed pairs. For nearly optimally doped samples, the
fluctuation conductivity can be accounted for by gaussian fluctuations
following the Ginzburg-Landau scheme. A phase fluctuation contribution might be
invoked for the most underdoped samples in a T range which increases when
controlled disorder is introduced by electron irradiation. Quantitative
analysis of the fluctuating magnetoconductance allows us to determine the
critical field Hc2(0) which is found to be quite similar to H'c(0) and to
increase with hole doping. Studies of the incidence of disorder on both T'c and
T* enable us to propose a three dimensional phase diagram including a disorder
axis, which allows to explain most observations done in other cuprate families.


title:
Co atoms on Bi$_{2}$Se$_{3}$ revealing a coverage dependent spin
  reorientation transition

abstract:
  We investigate Co nanostructures on Bi$_{2}$Se$_{3}$ by means of scanning
tunneling microscopy and spectroscopy [STM/STS], X-ray absorption spectroscopy
[XAS], X-ray magnetic dichroism [XMCD] and calculations using the density
functional theory [DFT]. In the single adatom regime we find two different
adsorption sites by STM. Our calculations reveal these to be the fcc and hcp
hollow sites of the substrate. STS shows a pronounced peak for only one species
of the Co adatoms indicating different electronic properties of both types.
These are explained on the basis of our DFT calculations by different
hybridizations with the substrate. Using XMCD we find a coverage dependent spin
reorientation transition from easy-plane toward out-of-plane. We suggest
clustering to be the predominant cause for this observation.


title: Vortical field amplification and particle acceleration at rippled shocks

abstract:
  Supernova Remnants (SNRs) shocks are believed to accelerate charged particles
and to generate strong turbulence in the post-shock flow. From high-energy
observations in the past decade, a magnetic field at SNR shocks largely
exceeding the shock-compressed interstellar field has been inferred. We outline
how such a field amplification results from a small-scale dynamo process
downstream of the shock, providing an explicit expression for the turbulence
back-reaction to the fluid whirling. The spatial scale of the $X-$ray rims and
the short time-variability can be obtained by using reasonable parameters for
the interstellar turbulence. We show that such a vortical field saturation is
faster than the acceleration time of the synchrotron emitting energetic
electrons.


title: Further studies of QCD with sextet quarks

abstract:
  We continue our simulations of QCD with 2 flavours of colour-sextet quarks as
a model for walking technicolor. QCD with 3 flavours of colour-sextet quarks is
also studied for comparison with the 2-flavour theory. We simulate these
theories at finite temperatures T, using lattices with a finite extent $N_t
a=1/T$ in the (Euclidean) time direction. The lattice coupling at the
chiral-symmetry-restoration transition is measured as a function of $N_t$. If
this is indeed a finite-temperature transition, the evolution of this coupling
with $N_t$ as $N_t \rightarrow \infty$ and hence the lattice spacing $a
\rightarrow 0$ should be described by asymptotic freedom. If so, the theory is
QCD-like and walking. If, however, this coupling approaches a constant non-zero
value in the large $N_t$ limit, the transition is a bulk transition and the
continuum theory is conformal. For the 2-flavour theory, the coupling does show
a significant decrease between $N_t=8$ and $N_t=12$, favouring the walking
scenario. However, preliminary results are that the change is less than that
predicted by asymptotic freedom. For the 3-flavour case, which is expected to
be conformal, there is still a significant decrease in the coupling between
$N_t=6$ and $N_t=8$, indicating that we are not yet at large enough $N_t$.


title: The theory of individual based discrete-time processes

abstract:
  A general theory is developed to study individual based models which are
discrete in time. We begin by constructing a Markov chain model that converges
to a one-dimensional map in the infinite population limit. Stochastic
fluctuations are hence intrinsic to the system and can induce qualitative
changes to the dynamics predicted from the deterministic map. From the
Chapman-Kolmogorov equation for the discrete-time Markov process, we derive the
analogues of the Fokker-Planck equation and the Langevin equation, which are
routinely employed for continuous time processes. In particular, a stochastic
difference equation is derived which accurately reproduces the results found
from the Markov chain model. Stochastic corrections to the deterministic map
can be quantified by linearizing the fluctuations around the attractor of the
map. The proposed scheme is tested on stochastic models which have the logistic
and Ricker maps as their deterministic limits.


title:
Analysis of the quark sector in the 2HDM-III with a four-zero Yukawa
  texture using the most recent data on the CKM matrix

abstract:
  In this letter we analyse, in the context of the general 2-Higgs Doublet
Model, the structure of the Yukawa matrices, $\widetilde{ \bf Y}_{ _{1,2}
}^{q}$, by assuming a four-zero texture ansatz for their definition. In this
framework, we obtain compact expressions for $\widetilde{ \bf Y}_{ _{1,2}
}^{q}$, which are reduced to the Cheng and Sher ansatz with the difference that
they are obtained naturally as a direct consequence of the invariants of the
fermion mass matrices. Furthermore, in order to avoid large flavour violating
effects coming from charged Higgs exchange, we consider the main flavour
constraints on the off-diagonal terms of Yukawa texture {{$\left(
\widetilde{\chi}_{j}^q \right)_{kl}$}} ($k\neq l$). We perform a $\chi^2$-fit
based on current experimental data on the quark masses and the
Cabibbo-Kobayashi-Maskawa mixing matrix ${ \bf V}_{\rm CKM }$. Hence, we obtain
the allowed ranges for the parameters $\widetilde{ \bf Y}_{ _{1,2} }^{q}$ at
1$\sigma$ for several values of $\tan \beta$. The results are in complete
agreement with the bounds obtained taking into account constraints on Flavour
Changing Neutral Currents reported in the literature.


title: Remark on repo and options

abstract:
  The general and special repo rates are related with the prices of the
European call- and American put-options. The evaluation takes into account
specific business models of the parties in the repo agreement and the law
restrictions. Using the repo-option relation, an alternative to the
Black-Scholes method of option pricing is presented. The empirical data on the
general and special repo rates are explained.


title: Robust quantum data locking from phase modulation

abstract:
  Quantum data locking is a unique quantum phenomenon that allows a relatively
short key to (un)lock an arbitrarily long message encoded in a quantum state,
in such a way that an eavesdropper who measures the state but does not know the
key has essentially no information about the encrypted message. The application
of quantum data locking in cryptography would allow one to overcome the
limitations of the one-time pad encryption, which requires the key to have the
same length as the message. However, it is known that the strength of quantum
data locking is also its Achilles heel, as the leakage of a few bits of the key
or the message may in principle allow the eavesdropper to unlock a
disproportionate amount of information. In this paper we show that there exist
quantum data locking schemes that can be made robust against information
leakage by increasing the length of the shared key by a proportionate amount.
This implies that a constant size key can still encrypt an arbitrarily long
message as long as a fraction of it remains secret to the eavesdropper.
Moreover, we greatly simplify the structure of the protocol by proving that
phase modulation suffices to generate strong locking schemes, paving the way to
optical experimental realizations. Also, we show that successful data locking
protocols can be constructed using random codewords, which very well could be
helpful in discovering random codes for data locking over noisy quantum
channels.


title: Vorticity survival in magnetised Friedmann universes

abstract:
  We use a general relativistic approach to investigate the effects of weak
cosmological magnetic fields on linear rotational perturbations during the
radiation and dust epochs of the universe. This includes ordinary kinematic
vorticity, as well as vortex-like inhomogeneities in the density distribution
of the cosmic medium. Our study confirms that magnetic fields can source both
types of perturbations and shows that their presence also helps cosmic rotation
to survive longer. In agreement with previous Newtonian studies, we find that
during the dust era vorticity decays slower than in non-magnetised cosmologies.
Prior to equipartition the magnetic effect is more pronounced, since it helps
the aforementioned rotational distortions to maintain constant magnitude.
Overall, magnetised universes seem to provide a much better environment for the
survival of cosmic vorticity than their magnetic-free counterparts.


title: Magnetometry with nitrogen-vacancy defects in diamond

abstract:
  The isolated electronic spin system of the Nitrogen-Vacancy (NV) centre in
diamond offers unique possibilities to be employed as a nanoscale sensor for
detection and imaging of weak magnetic fields. Magnetic imaging with nanometric
resolution and field detection capabilities in the nanotesla range are enabled
by the atomic-size and exceptionally long spin-coherence times of this
naturally occurring defect. The exciting perspectives that ensue from these
characteristics have triggered vivid experimental activities in the emerging
field of "NV magnetometry". It is the purpose of this article to review the
recent progress in high-sensitivity nanoscale NV magnetometry, generate an
overview of the most pertinent results of the last years and highlight
perspectives for future developments. We will present the physical principles
that allow for magnetic field detection with NV centres and discuss first
applications of NV magnetometers that have been demonstrated in the context of
nano magnetism, mesoscopic physics and the life sciences.


title:
Mixed mode oscillations in the Bonhoeffer-van der Pol oscillator with
  weak periodic perturbation

abstract:
  Following the paper of K. Shimizu et al. (2011) we consider the
Bonhoeffer-van der Pol oscillator with non-autonomous periodic perturbation. We
show that the presence of mixed mode oscillations reported in that paper can be
explained using the geometrical theory of singular perturbations. The
considered model can be re-written as a 4-dimensional (locally 3-dimensional)
autonomous system, which under certain conditions has a folded saddle-node
singularity and additionally can be treated as a three time scale one.


title: Relaxation after quantum quenches in the spin-1/2 Heisenberg XXZ chain

abstract:
  We consider the time evolution after quantum quenches in the spin-1/2
Heisenberg XXZ quantum spin chain with Ising-like anisotropy. The time
evolution of short-distance spin-spin correlation functions is studied by
numerical tensor network techniques for a variety of initial states, including
N\'eel and Majumdar-Ghosh states and the ground state of the XXZ chain at large
values of the anisotropy. The various correlators appear to approach stationary
values, which are found to be in good agreement with the results of exact
calculations of stationary expectation values in appropriate generalized Gibbs
ensembles. In particular, our analysis shows how symmetries of the post-quench
Hamiltonian that are broken by particular initial states are restored at late
times.

categories: cond-mat.stat-mech math-ph math.MP quant-ph


title: Representation theory of Mackey Lie algebras and their dense subalgebras

abstract:
  In this article we review the main results of the earlier papers [I. Penkov,
K. Styrkas, Tensor representations of infinite-dimensional root-reductive Lie
algebras, in Developments and Trends in Infinite-Dimensional Lie Theory,
Progress in Mathematics 288, Birkh\"auser, 2011, pp. 127-150], [I. Penkov, V.
Serganova, Categories of integrable $\mathfrak{sl}(\infty)$-,
$\mathfrak{o}(\infty)$-, $\mathfrak{sp}(\infty)$-modules, in "Representation
Theory and Mathematical Physics", Contemporary Mathematics 557 (2011), pp.
335-357] and [E. Dan-Cohen, I. Penkov, V. Serganova, A Koszul category of
representations of finitary Lie algebras, preprint 2011, arXiv:1105.3407], and
establish related new results in considerably greater generality. We introduce
a class of infinite-dimensional Lie algebras $\mathfrak{g}^{M}$, which we call
Mackey Lie algebras, and define monoidal categories
$\mathbb{T}_{\mathfrak{g}^M}$ of tensor $\mathfrak{g}^M-$modules. We also
consider dense subalgebras $\mathfrak{a} \subset \mathfrak{g}^M$ and
corresponding categories $\mathbb{T}_\mathfrak{a}$. The locally finite Lie
algebras $\mathfrak{sl}(V,W), \mathfrak{o}(V), \mathfrak{sp}(V)$ are dense
subalgebras of respective Mackey Lie algebras. Our main result is that if
$\mathfrak{g}^M$ is a Mackey Lie algebra and $\mathfrak{a} \subset
\mathfrak{g}^M$ is a dense subalgebra, then the monoidal category
$\mathbb{T}_\mathfrak{a}$ is equivalent to $\mathbb{T}_{\mathfrak{sl}(\infty)}$
or $\mathbb{T}_{\mathfrak{o}(\infty)}$; the latter monoidal categories have
been studied in detail in [E. Dan-Cohen, I. Penkov, V. Serganova, A Koszul
category of representations of finitary Lie algebras, preprint 2011,
arXiv:1105.3407]. A possible choice of $\mathfrak{a}$ is the well-known Lie
algebra of generalized Jacobi matrices.


title:
Influence of Shear Motion on Evolution of Molecular Clouds in the Spiral
  Galaxy M51

abstract:
  We have investigated the dynamics of the molecular gas and the evolution of
GMAs in the spiral galaxy M51 with the NRO 45-m telescope. The velocity
components of the molecular gas perpendicular and parallel to the spiral arms
are derived at each spiral phase from the distribution of the line-of-sight
velocity of the CO gas. In addition, the shear motion in the galactic disk is
determined from the velocity vectors at each spiral phase. It is revealed that
the distributions of the shear strength and of GMAs are anti-correlated. GMAs
exist only in the area of the weak shear strength and further on the upstream
side of the high shear strength. GMAs and most of GMCs exist in the regions
where the shear critical surface density is smaller than the gravitational
critical surface density, indicating that they can stably grow by self-gravity
and the collisional agglomeration of small clouds without being destroyed by
shear motion. These indicate that the shear motion is an important factor in
evolution of GMCs and GMAs.


title:
Dynamical properties in uniform and periodic growth modes of ascorbic
  acid crystal domain from thin solution film

abstract:
  There exists the threshold-sensitive dynamical transition between the uniform
and the periodic growth modes in the domain growth of ascorbic acid crystals
from its aqueous supersaturated solution film. The crystal growth induces the
solution flow. Humidity controls the fluidity of the solution. The solution
flow varies the film thickness. The threshold exists in the thickness of the
solution film, and the crystal growth almost stops if the thickness becomes
lower than the threshold.


title:
Convergence Tools for Consensus in Multi-Agent Systems with Switching
  Topologies

abstract:
  We present two main theorems along the lines of Lyapunov's second method that
guarantee asymptotic state consensus in multi-agent systems of agents in R^m
with switching interconnection topologies. The two theorems complement each
other in the sense that the first one is formulated in terms of the states of
the agents in the multi-agent system, whereas the second one is formulated in
terms of the pairwise states for each pair of agents in the multi-agent system.
In the first theorem, under the assumption that the interconnection topology is
uniformly strongly connected and the agents are contained in a compact set, a
strong form of attractiveness of the consensus set is assured. In the second
theorem, under the weaker assumption that the interconnection topology is
uniformly quasi strongly connected, the consensus set is guaranteed to be
uniformly asymptotically stable.


title:
An exact framework for uncertainty quantification in Monte Carlo
  simulation

abstract:
  In the context of Monte Carlo (MC) simulation of particle transport
Uncertainty Quantification (UQ) addresses the issue of predicting non
statistical errors affecting the physical results, i.e. errors deriving mainly
from uncertainties in the physics data and/or in the model they embed. In the
case of a single uncertainty a simple analytical relation exists among its the
Probability Density Function (PDF) and the corresponding PDF for the output of
the simulation: this allows a complete statistical analysis of the results of
the simulation. We examine the extension of this result to the multi-variate
case, when more than one of the physical input parameters are affected by
uncertainties: a typical scenario is the prediction of the dependence of the
simulation on input cross section tabulations.

categories: physics.comp-ph hep-ex nucl-th physics.data-an


title: On the Outer Edges of Protoplanetary Dust Disks

abstract:
  The expectation that aerodynamic drag will force the solids in a gas-rich
protoplanetary disk to spiral in toward the host star on short timescales is
one of the fundamental problems in planet formation theory. The nominal
efficiency of this radial drift process is in conflict with observations,
suggesting that an empirical calibration of solid transport mechanisms in a
disk is highly desirable. However, the fact that both radial drift and grain
growth produce a similar particle size segregation in a disk (such that larger
particles are preferentially concentrated closer to the star) makes it
difficult to disentangle a clear signature of drift alone. We highlight a new
approach, by showing that radial drift leaves a distinctive "fingerprint" in
the dust surface density profile that is directly accessible to current
observational facilities. Using an analytical framework for dust evolution, we
demonstrate that the combined effects of drift and (viscous) gas drag naturally
produce a sharp outer edge in the dust distribution (or, equivalently, a sharp
decrease in the dust-to-gas mass ratio). This edge feature forms during the
earliest phase in the evolution of disk solids, before grain growth in the
outer disk has made much progress, and is preserved over longer timescales when
both growth and transport effects are more substantial. The key features of
these analytical models are reproduced in detailed numerical simulations, and
are qualitatively consistent with recent millimeter-wave observations that find
gas/dust size discrepancies and steep declines in dust continuum emission in
the outer regions of protoplanetary disks.


title:
Lyman-{\alpha} Forest and Cosmic Weak Lensing in a Warm Dark Matter
  Universe

abstract:
  We review the current state of the theory of large scale structure in a warm
dark matter (WDM) cosmological model. In particular, we focus on the non-linear
modelling of the matter power spectrum and on the mass function of dark matter
haloes. We describe the results of N-body simulations with WDM and mention the
effects that could be induced by baryonic physics. We also examine the halo
model of large scale structure and its recently suggested modifications for a
WDM cosmology, which account for the small scale smoothness of the initial
matter density field and better fit the results of N-body simulations. Having
described the theoretical models, we discuss the current lower limits on the
WDM particle mass, m_w, which correspond to upper limits on the WDM temperature
under the assumption that the particles are thermal relics. The best such
constraints come from the Ly{\alpha} forest and exclude all masses below 3.3
keV at the 2{\sigma} confidence level. We finally review the forecasts for
future lensing surveys, which will be of the same order of magnitude as the
already existing constraints from the Ly{\alpha} forest data but explore a
different redshift regime.


title:
Consistent use of Type Ia supernovae highly magnified by galaxy clusters
  to constrain the cosmological parameters

abstract:
  We discuss how Type Ia supernovae (SNe) strongly magnified by foreground
galaxy clusters should be self-consistently treated when used in samples fitted
for the cosmological parameters. While the cluster lens magnification of a SN
can be well constrained from sets of multiple images of various background
galaxies with measured redshifts, its value is typically dependent on the
fiducial set of cosmological parameters used to construct the mass model to
begin with. In such cases, one should not naively demagnify the observed SN
luminosity by the model magnification into the expected Hubble diagram, which
would then create a bias, but take into account the cosmological parameters
a-priori chosen to construct the mass model. We quantify the effect and find
that a systematic error of typically a few percent, up to a few-dozen percent,
per magnified SN, may be propagated onto a cosmological parameter fit, unless
the cosmology assumed for the mass model is taken into account (the bias can be
even larger if the SN is lying very near the critical curves). We also simulate
how such a bias propagates onto the cosmological parameter fit using the
Union2.1 sample, supplemented with strongly magnified SNe. The resulting bias
on the deduced cosmological parameters is generally at the few percent level,
if only few biased SNe are included, and increasing with the number of lensed
SNe and their redshift. Samples containing magnified Type Ia SNe, e.g. from
ongoing cluster surveys, should readily account for this possible bias.


title: Generating Merger Trees for Dark Matter Haloes: A Comparison of Methods

abstract:
  Halo merger trees describe the hierarchical mass assembly of dark matter
haloes, and are the backbone for modeling galaxy formation and evolution.
Merger trees constructed using Monte Carlo algorithms based on the extended
Press-Schechter (EPS) formalism are complementary to those extracted from
N-body simulations, and have the advantage that they are not trammeled by
limited numerical resolution and uncertainties in identifying (sub)haloes and
linking them between snapshots. This paper compares multiple EPS-based merger
tree algorithms to simulation results using four diagnostics: progenitor mass
function (PMF), mass assembly history (MAH), merger rate per descendant halo,
and the unevolved subhalo mass function (USMF). In general, algorithms based on
spherical collapse yield major-merger rates that are too high by a factor of
two, resulting in MAHs that are systematically offset. Assuming ellipsoidal
collapse solves most of these issues, but the particular algorithm investigated
here that incorporates ellipsoidal collapse dramatically overpredicts the
minor-merger rate for massive haloes. The only algorithm in our comparison that
yields MAHs, merger rates, and USMFs in good agreement with simulations, is
that by Parkinson et al. (2008). However, this is not a true EPS-based
algorithm as it draws its progenitor masses from a PMF calibrated against
simulations, rather than `predicted' by EPS. Finally we emphasize that the
benchmarks used to test the EPS algorithms are obtained from simulations and
are hampered by significant uncertainties themselves. In particular, MAHs and
halo merger rates obtained from simulations by different authors reveal
discrepancies that easily exceed 50 percent, even when based on the same
simulation. Given this status quo, merger trees constructed using the Parkinson
et al. algorithm are as accurate as those extracted from N-body simulations.


title:
Cosmological Constraints from the Anisotropic Clustering Analysis using
  BOSS DR9

abstract:
  Our observations of the Universe are fundamentally anisotropic, with data
from galaxies separated transverse to the line of sight coming from the same
epoch while that from galaxies separated parallel to the line of sight coming
from different times. Moreover, galaxy velocities along the line of sight
change their redshift, giving redshift space distortions. We perform a full
two-dimensional anisotropy analysis of galaxy clustering data, fitting in a
substantially model independent manner the angular diameter distance D_A,
Hubble parameter H, and growth rate ddelta/dln a without assuming a dark energy
model. The results demonstrate consistency with LCDM expansion and growth,
hence also testing general relativity. We also point out the interpretation
dependence of the effective redshift z_eff, and its cosmological impact for
next generation surveys.


title: ADHM Construction of Noncommutative Instantons

abstract:
  We discuss the Atiyah-Drinfeld-Hitchin-Manin (ADHM) construction of U(N)
instantons in noncommutative (NC) space and prove the one-to-one correspondence
between moduli spaces of the noncommutative instantons and the ADHM data,
together with an origin of the instanton number for U(1). We also give a
derivation of the ADHM construction from the viewpoint of the Nahm
transformation of instantons on four-tori. This article is a composite version
of [23] and [24].


title:
Hidden Starbursts and Active Galactic Nuclei at 0<z<4 from the
  Herschel-VVDS-CFHTLS-D1 Field: Inferences on Coevolution and Feedback

abstract:
  We investigate of the properties of $\sim$2000 Herschel/SPIRE-selected
galaxies from $0<z<4$ using a combination of extensive spectroscopy, deep
imaging from CFHT, VLA, Spitzer, XMM-Newton, and Herschel, and well-calibrated
SED fitting. Herschel galaxies are observed to span a range of stellar masses,
colors, and absolute magnitudes equivalent to galaxies undetected in SPIRE.
Though many Herschel galaxies appear to be in transition, such galaxies are
largely consistent with normal star-forming galaxies when rest-frame colors are
utilized. The nature of the star-forming "main sequence" is studied and we warn
against adopting this framework unless the main sequence is determined
precisely. Herschel galaxies at different total infrared luminosities
($L_{TIR}$) are compared. Bluer colors, larger nebular extinctions, and larger
contributions from younger stellar populations are observed for galaxies with
larger $L_{TIR}$, suggesting that low-$L_{TIR}$ galaxies are undergoing
rejuvenated starbursts while galaxies with higher $L_{TIR}$ are forming a
larger percentage of their stellar mass. A variety of methods are used to
select powerful active galactic nuclei (AGN). Galaxies hosting AGN are observed
to be undergoing starbursts more commonly and vigorously than a matched sample
of galaxies without powerful AGN and, additionally, the fraction of galaxies
with an AGN increases with increasing star formation rate at all redshifts. At
all redshifts ($0<z<4$) the most prodigious star-forming galaxies are found to
contain the highest fraction of powerful AGN. For redshift bins that allow a
comparison ($z>0.5$), the highest $L_{TIR}$ galaxies in a given redshift bin
are unobserved by SPIRE at subsequently lower redshifts, a trend linked to
downsizing. In conjunction with other results, this evidence is used to argue
for prevalent AGN-driven quenching in starburst galaxies across cosmic time.


title:
RUN DMC: An efficient, parallel code for analyzing Radial Velocity
  Observations using N-body Integrations and Differential Evolution Markov
  chain Monte Carlo

abstract:
  In the 20+ years of Doppler observations of stars, scientists have uncovered
a diverse population of extrasolar multi-planet systems. A common technique for
characterizing the orbital elements of these planets is Markov chain Monte
Carlo (MCMC), using a Keplerian model with random walk proposals and paired
with the Metropolis-Hastings algorithm. For approximately a couple of dozen
planetary systems with Doppler observations, there are strong planet-planet
interactions due to the system being in or near a mean-motion resonance (MMR).
An N-body model is often required to accurately describe these systems. Further
computational difficulties arise from exploring a high-dimensional parameter
space ($\sim$7 x number of planets) that can have complex parameter
correlations. To surmount these challenges, we introduce a differential
evolution MCMC (DEMCMC) applied to radial velocity data while incorporating
self-consistent N-body integrations. Our Radial velocity Using N-body DEMCMC
(RUN DMC) algorithm improves upon the random walk proposal distribution of the
traditional MCMC by using an ensemble of Markov chains to adaptively improve
the proposal distribution. We describe the methodology behind the algorithm,
along with results of tests for accuracy and performance. We find that most
algorithm parameters have a modest effect on the rate of convergence. However,
the size of the ensemble can have a strong effect on performance. We show that
the optimal choice depends on the number of planets in a system, as well as the
computer architecture used and the resulting extent of parallelization. While
the exact choices of optimal algorithm parameters will inevitably vary due to
the details of individual planetary systems, we offer recommendations for
choosing the DEMCMC algorithm's algorithmic parameters that result in excellent
performance for a wide variety of planetary systems.


title:
The stellar mass function and efficiency of galaxy formation with a
  varying initial mass function

abstract:
  Several recent observational studies have concluded that the initial mass
function (IMF) of stars varies systematically with galaxy properties such as
velocity dispersion. In this paper, we investigate the effect of linking the
circular velocity of galaxies, as determined from the Fundamental Plane and
Tully-Fisher relations, to the slope of the IMF with parameterizations guided
by several of these studies. For each empirical relation, we generate stellar
masses of ~600,000 SDSS galaxies at z ~ 0.1, by fitting the optical photometry
to large suites of synthetic stellar populations that sample the full range of
galaxy parameters. We generate stellar mass functions and examine the
stellar-to-halo mass relations using sub-halo abundance matching. At the
massive end, the stellar mass functions become a power law, instead of the
familiar exponential decline. As a result, it is a generic feature of these
models that the central galaxy stellar-to-halo mass relation is significantly
flatter at high masses (slope ~ -0.3 to -0.4) than in the case of a universal
IMF (slope ~ -0.6). We find that regardless of whether the IMF varies
systematically in all galaxies or just early types, there is still a
well-defined peak in the central stellar-to-halo mass ratio at halo masses of ~
10E12 solar masses. In general, the IMF variations explored here lead to
significantly higher integrated stellar densities if the assumed dependence on
circular velocity applies to all galaxies, including late-types; in fact the
more extreme cases can be ruled out, as they imply an unphysical situation in
which the stellar fraction exceeds the universal baryon fraction.


title: Topological gaps without masses in driven graphene-like systems

abstract:
  We illustrate the possibility of realizing band gaps in graphene-like systems
that fall outside the existing classification of gapped Dirac Hamiltonians in
terms of masses. As our primary example we consider a band gap arising due to
time-dependent distortions of the honeycomb lattice. By means of an exact,
invertible, and transport-preserving mapping to a time-independent Hamiltonian,
we show that the system exhibits Chern-insulating phases with quantized Hall
conductivities $\pm e^2/h$. The chirality of the corresponding gapless edge
modes is controllable by both the frequency of the driving and the manner in
which sublattice symmetry is broken by the dynamical lattice modulations.
Finally, we discuss a promising possible realization of this physics in
photonic lattices.


title:
Star Formation in Orion's L1630 Cloud: an Infrared and Multi-epoch X-ray
  Study

abstract:
  X-ray emission is characteristic of young stellar objects (YSOs) and is known
to be highly variable. We investigate, via an infrared and multi-epoch X-ray
study of the L1630 dark cloud, whether and how X-ray variability in young
stellar objects is related to protostellar evolutionary state. We have analyzed
11 Chandra X-ray Observatory observations, obtained over the course of four
years and totaling ~240 ks exposure time, targeting the eruptive Class I YSO
V1647 Ori in L1630. We used 2MASS and Spitzer data to identify and classify IR
counterparts to L1630 X-ray sources and identified a total of 52 X-ray emitting
YSOs with IR counterparts, including 4 Class I sources and 1 Class 0/I source.
We have detected cool (< 3 MK) plasma, possibly indicative of accretion shocks,
in three classical T Tauri stars. A subsample of 27 X-ray-emitting YSOs were
covered by 9 of the 11 Chandra observations targeting V1647 Ori and vicinity.
For these 27 YSOs, we have constructed X-ray light curves spanning
approximately four years. These light curves highlight the variable nature of
pre-main sequence X-ray emitting young stars; many of the L1630 YSOs vary by
orders of magnitude in count rate between observations. We discuss possible
scenarios to explain apparent trends between various X-ray spectral properties,
X-ray variance and YSO classification.


title:
Topological Criticality in the Chiral-Symmetric AIII Class at Strong
  Disorder

abstract:
  The chiral AIII symmetry class in the periodic table of topological
insulators contains topological phases classified by a winding number $\nu$ for
each odd space-dimension. An open problem for this class is the
characterization of the phases and phase-boundaries in the presence of strong
disorder. In this work, we derive a covariant real-space formula for $\nu$ and,
using an explicit 1-dimensional disordered topological model, we show that
$\nu$ remains quantized and non-fluctuating when disorder is turned on, even
though the bulk energy-spectrum is completely localized. Furthermore, $\nu$
remains robust even after the insulating gap is filled with localized states,
but when the disorder is increased even further, an abrupt change of $\nu$ to a
trivial value is observed. Using exact analytic calculations, we show that this
marks a critical point where the localization length diverges. As such, in the
presence of disorder, the AIII class displays a markedly different physics from
everything known to date, with robust invariants being carried entirely by
localized states and bulk extended states emerging from an absolutely localized
spectrum. Detailed maps and a clear physical description of the phases and
phase boundaries are presented based on numerical and exact analytic
calculations.


title: Jet Veto Clustering Logarithms Beyond Leading Order

abstract:
  Many experimental analyses separate events into exclusive jet bins, using a
jet algorithm to cluster the final state and then veto on jets. Jet clustering
induces logarithmic dependence on the jet radius R in the cross section for
exclusive jet bins, a dependence that is poorly controlled due to the
non-global nature of the clustering. At jet radii of experimental interest, the
leading order (LO) clustering effects are numerically significant, but the
higher order effects are currently unknown. We rectify this situation by
calculating the most important part of the next-to-leading order (NLO)
clustering logarithms of R for any 0-jet process, which enter as
$O(\alpha_s^3)$ corrections to the cross section. The calculation blends
subtraction methods for NLO calculations with factorization properties of QCD
and soft-collinear effective theory (SCET). We compare the size of the known LO
and new NLO clustering logarithms and find that the impact of the NLO terms on
the 0-jet cross section in Higgs production is small. This brings clustering
effects under better control and may be used to improve uncertainty estimates
on cross sections with a jet veto.


title:
Zero-Field muSR Search for a Time-Reversal-Symmetry-Breaking Mixed
  Pairing State in Superconducting Ba1-xKxFe2As2

abstract:
  We report the results of a zero-field muon spin relaxation (ZF-muSR) study of
superconducting Ba1-xKxFe2As2 (0.5 < x < 0.9) in search of weak spontaneous
internal magnetic fields associated with proposed time-reversal-symmetry
breaking mixed pairing states. The measurements were performed on
polycrystalline samples, which do not exhibit the mesoscopic phase separation
previously observed in single crystals of Ba1-xKxFe2As2. No evidence of
spontaneous internal magnetic fields is found in any of the samples at
temperatures down to T ~ 0.02 K.


title: Timing variations in the secondary eclipse of NN Ser

abstract:
  The eclipsing white dwarf plus main-sequence binary NN Serpentis provides one
of the most convincing cases for the existence of circumbinary planets around
evolved binaries. The exquisite timing precision provided by the deep eclipse
of the white dwarf has revealed complex variations in the eclipse arrival times
over the last few decades. These variations have been interpreted as the
influence of two planets in orbit around the binary. Recent studies have proved
that such a system is dynamically stable over the current lifetime of the
binary. However, the existence of such planets is by no means proven and
several alternative mechanisms have been proposed that could drive similar
variations. One of these is apsidal precession, which causes the eclipse times
of eccentric binaries to vary sinusoidally on many year timescales. In this
paper we present timing data for the secondary eclipse of NN Ser and show that
they follow the same trend seen in the primary eclipse times, ruling out
apsidal precession as a possible cause for the variations. This result leaves
no alternatives to the planetary interpretation for the observed period
variations, although we still do not consider their existence as proven. Our
data limits the eccentricity of NN Ser to e<0.001. We also detect a 3.3+/-1.0
second delay in the arrival times of the secondary eclipses relative to the
best planetary model. This delay is consistent with the expected 2.84+/-0.04
second Romer delay of the binary, and is the first time this effect has been
detected in a white dwarf plus M dwarf system.


title:
On The Formation Of Multiple Absorption Troughs In Broad Absorption Line
  QSOs

abstract:
  We present theoretical CIV 1548,1550 absorption line profiles for QSOs
calculated assuming the accretion disk wind (ADW) scenario. The results suggest
that the multiple absorption troughs seen in many QSOs may be due to the
discontinuities in the ion balance of the wind (caused by X-rays), rather than
discontinuities in the density/velocity structure. The profiles are calculated
from a 2.5D time-dependent hydrodynamic simulation of a line-driven disk wind
for a typical QSO black hole mass, a typical QSO luminosity, and for a standard
Shakura-Sunyaev disk. We include the effects of ionizing X-rays originating
from within the inner disk radius by assuming that the wind is shielded from
the X-rays from a certain viewing angle up to 90o ("edge on"). In the shielded
region we assume constant ionization equilibrium, and thus constant line-force
parameters. In the non-shielded region we assume that both the line-force and
the C+3 populations are nonexistent. The model, at viewing angles close to the
angle that separates the shielded region and the non-shielded region, produces
absorption lines with multiple troughs. The steady nature of accretion disk
winds, in turn, may account for the steady nature of the absorption structure
observed in multiple-trough broad absorption line QSOs. The model parameters
are Mbh = 10^9 Msun and Ldisk = 10^47 erg s-1.


title:
Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube
  Detector

abstract:
  We report on results of an all-sky search for high-energy neutrino events
interacting within the IceCube neutrino detector conducted between May 2010 and
May 2012. The search follows up on the previous detection of two PeV neutrino
events, with improved sensitivity and extended energy coverage down to
approximately 30 TeV. Twenty-six additional events were observed, substantially
more than expected from atmospheric backgrounds. Combined, both searches reject
a purely atmospheric origin for the twenty-eight events at the $4\sigma$ level.
These twenty-eight events, which include the highest energy neutrinos ever
observed, have flavors, directions, and energies inconsistent with those
expected from the atmospheric muon and neutrino backgrounds. These properties
are, however, consistent with generic predictions for an additional component
of extraterrestrial origin.


title:
General aspects of the vapor growth of semiconductor crystals - a study
  based on DFT simulations of the NH3/NH2 covered GaN(0001) surface in hydrogen
  ambient

abstract:
  Vapor growth of semiconductors is analyzed using recently obtained dependence
of the adsorption energy on the electron charge transfer between the surface
adsorbed species and the bulk [Krukowski et al. J. Appl. Phys. 114 (2013)
063507, Kempisty et al. ArXiv 1307.5778 (2013)]. Ab initio calculations were
performed to study the physical properties of GaN(0001) surface in ammonia-rich
conditions, i.e. covered by mixture of NH3 molecules and NH2 radicals. The
Fermi level is pinned at valence band maximum (VBM) and conduction band minimum
(CBM) for full coverage by NH3 molecules and NH2 radicals, respectively. For
the crossover content of ammonia of about 25% monolayer (ML), the Fermi level
is unpinned. It was shown that hydrogen adsorption energy depends on the doping
in the bulk for the unpinned Fermi level, i.e. for this coverage. Surface
structure thermodynamic and mechanical stability criteria are defined and
compared. Mechanical stability of the coverage of such surfaces was checked by
determination of the desorption energy of hydrogen molecules. Thermodynamic
stability analysis indicates that initally equilibrium hydrogen vapor partial
pressure steeply increases with NH3 content to attain the crossover NH3/NH2
coverage, i.e. the unpinned Fermi level condition. For such condition the
entire range of experimentally accessible pressures belongs showing that vapor
growth of semiconductor crystals occurs predominantly for unpinned Fermi level
at the surface, i.e. for flat bands. Accordingly, adsorption energy of most
species depends on the doping in the bulk that is basis of the possible
molecular scenario explaining dependence of the growth and the doping of
semiconductor crystals on the doping in the bulk


title: PENLAB: A MATLAB solver for nonlinear semidefinite optimization

abstract:
  PENLAB is an open source software package for nonlinear optimization, linear
and nonlinear semidefinite optimization and any combination of these. It is
written entirely in MATLAB. PENLAB is a young brother of our code PENNON
\cite{pennon} and of a new implementation from NAG \cite{naglib}: it can solve
the same classes of problems and uses the same algorithm. Unlike PENNON, PENLAB
is open source and allows the user not only to solve problems but to modify
various parts of the algorithm. As such, PENLAB is particularly suitable for
teaching and research purposes and for testing new algorithmic ideas.
  In this article, after a brief presentation of the underlying algorithm, we
focus on practical use of the solver, both for general problem classes and for
specific practical problems.


title:
Evolution of linear perturbations in spherically symmetric dust
  spacetimes

abstract:
  We present results from a numerical code implementing a new method to solve
the master equations describing the evolution of linear perturbations in a
spherically symmetric but inhomogeneous background. This method can be used to
simulate several configurations of physical interest, such as relativistic
corrections to structure formation, the lensing of gravitational waves and the
evolution of perturbations in a cosmological void model. This paper focuses on
the latter problem, i.e. structure formation in a Hubble scale void in the
linear regime. This is considerably more complicated than linear perturbations
of a homogeneous and isotropic background because the inhomogeneous background
leads to coupling between density perturbations and rotational modes of the
spacetime geometry, as well as gravitational waves. Previous analyses of this
problem ignored this coupling in the hope that the approximation does not
affect the overall dynamics of structure formation in such models. We show that
for a giga-parsec void, the evolution of the density contrast is well
approximated by the previously studied decoupled evolution only for very
large-scale modes. However, the evolution of the gravitational potentials
within the void is inaccurate at more than the $10\%$ level, and is even worse
on small scales.


title:
An Improved Variable Step-size Affine Projection Sign Algorithm for Echo
  Cancellation

abstract:
  This paper proposes an improved variable step-size (VSS) algorithm for the
recently introduced affine projection sign algorithm (APSA) based on the
recovery of the near-end signal energy in the error signal. Simulation results
demonstrate that, compared to the previous VSS for APSA, the proposed approach
provides both more robustness to impulse interference and better tracking
ability of echo path change.


title: Solar Eruptive Events (SEE) 2020 Mission Concept

abstract:
  Major solar eruptive events (SEEs), consisting of both a large flare and a
near simultaneous large fast coronal mass ejection (CME), are the most powerful
explosions and also the most powerful and energetic particle accelerators in
the solar system, producing solar energetic particles (SEPs) up to tens of GeV
for ions and hundreds of MeV for electrons. The intense fluxes of escaping SEPs
are a major hazard for humans in space and for spacecraft. Furthermore, the
solar plasma ejected at high speed in the fast CME completely restructures the
interplanetary medium (IPM) - major SEEs therefore produce the most extreme
space weather in geospace, the interplanetary medium, and at other planets.
Thus, understanding the flare/CME energy release process(es) and the related
particle acceleration processes are major goals in Heliophysics. To make the
next major breakthroughs, we propose a new mission concept, SEE 2020, a single
spacecraft with a complement of advanced new instruments that focus directly on
the coronal energy release and particle acceleration sites, and provide the
detailed diagnostics of the magnetic fields, plasmas, mass motions, and
energetic particles required to understand the fundamental physical processes
involved.


title:
A Generalized Markov-Chain Modelling Approach to $(1,\lambda )$-ES
  Linear Optimization

abstract:
  The manuscript generalizes several recent results of the 2nd author
concerning Markov-Chain Modelling of $(1,\lambda )$-ES Linear Optimization.


title:
NuSTAR Observations of GRB130427A establish a single component
  synchrotron afterglow origin for the late optical to multi-GeV emission

abstract:
  GRB 130427A occurred in a relatively nearby galaxy; its prompt emission had
the largest GRB fluence ever recorded. The afterglow of GRB 130427A was bright
enough for the Nuclear Spectroscopic Telescope ARray (NuSTAR) to observe it in
the 3-79 keV energy range long after its prompt emission (~1.5 and 5 days).
This range, where afterglow observations were previously not possible, bridges
an important spectral gap. Combined with Swift, Fermi and ground-based optical
data, NuSTAR observations unambiguously establish a single afterglow spectral
component from optical to multi-GeV energies a day after the event, which is
almost certainly synchrotron radiation. Such an origin of the late-time
Fermi/LAT > 10 GeV photons requires revisions in our understanding of
collisionless relativistic shock physics.


title:
2MASS Photometric Redshift catalog: a comprehensive three-dimensional
  census of the whole sky

abstract:
  Key cosmological applications require the three-dimensional galaxy
distribution on the entire celestial sphere. These include measuring the
gravitational pull on the Local Group, estimating the large-scale bulk flow and
testing the Copernican principle. However, the largest all-sky redshift surveys
-- the 2MRS and IRAS PSCz -- have median redshifts of only z=0.03 and sample
the very local Universe. There exist all-sky galaxy catalogs reaching much
deeper -- SuperCOSMOS in the optical, 2MASS in the near-IR and WISE in the
mid-IR -- but these lack complete redshift information. At present, the only
rapid way towards larger 3D catalogs covering the whole sky is through
photometric redshift techniques. In this paper we present the 2MASS Photometric
Redshift catalog (2MPZ) containing 1 million galaxies, constructed by
cross-matching 2MASS XSC, WISE and SuperCOSMOS all-sky samples and employing
the artificial neural network approach (the ANNz algorithm), trained on such
redshift surveys as SDSS, 6dFGS and 2dFGRS. The derived photometric redshifts
have errors nearly independent of distance, with an all-sky accuracy of
sigma_z=0.015 and a very small percentage of outliers. In this way, we obtain
redshift estimates with a typical precision of 12% for all the 2MASS XSC
galaxies that lack spectroscopy. In addition, we have made an early effort
towards probing the entire 3D sky beyond 2MASS, by pairing up WISE with
SuperCOSMOS and training the ANNz on GAMA redshift data reaching currently to
z_med~0.2. This has yielded photo-z accuracies comparable to those in the 2MPZ.
These all-sky photo-z catalogs, with a median z~0.1 for the 2MPZ, and
significantly deeper for future WISE-based samples, will be the largest and
most complete of their kind for the foreseeable future.


title:
Strong-Field Many-Body Physics and the Giant Enhancement in the
  High-Harmonic Spectrum of Xenon

abstract:
  We resolve an open question about the origin of the giant enhancement in the
high-harmonic generation (HHG) spectrum of atomic xenon around 100 eV. By
solving the many-body time-dependent Schr\"odinger equation with all orbitals
in the 4d, 5s, and 5p shells active, we demonstrate the enhancement results
truly from collective many-body excitation induced by the returning
photoelectron via two-body interchannel interactions. Without the many-body
interactions, which promote a 4d electron into the 5p vacancy created by
strong-field ionization, no collective excitation and no enhancement in the HHG
spectrum exist.


title: New detections of radio minihalos in cool cores of galaxy clusters

abstract:
  Cool cores of some galaxy clusters exhibit faint radio "minihalos." Their
origin is unclear; their study has been limited by their small number. We
undertook a systematic search for minihalos in a large sample of X-ray luminous
clusters with high-quality radio data. In this paper, we report four new
minihalos (A 478, ZwCl 3146, RXJ 1532.9+3021 and A 2204), and five candidates,
found in the reanalyzed archival Very Large Array observations. The radio
luminosities of our minihalos and candidates are in the range $10^{23-25}$ W
Hz$^{-1}$ at 1.4 GHz, consistent with this type of radio sources. Their sizes
(40-160 kpc in radius) are somewhat smaller than those of the previously known
minihalos. We combine our new detections with previously known minihalos,
obtaining a total sample of 21 objects, and briefly compare the cluster radio
properties to the average X-ray temperature and the total masses estimated from
Planck. We find that nearly all clusters hosting minihalos are hot and massive.
Beyond that, there is no clear correlation between the minihalo radio power and
cluster temperature or mass (in contrast with the giant radio halos found in
cluster mergers, whose radio luminosity correlates with the cluster mass).
Chandra X-ray images indicate gas sloshing in the cool cores of most of our
clusters, with minihalos contained within the sloshing regions in many of them.
This supports the hypothesis that radio-emitting electrons are reaccelerated by
sloshing. Advection of relativistic electrons by the sloshing gas may also play
a role in the formation of the less-extended minihalos.


title: Efficiency Gains from Using Auxiliary Variables in Imputation

abstract:
  Imputation models sometimes use auxiliary variables that, though not part of
the planned analysis, can improve the accuracy of imputed values and the
efficiency of point estimates. A recent article, using evidence from
simulations, argued that the use of auxiliary variables in imputation did not
improve efficiency. We review the simulation results and find that the use of
auxiliary variables did improve efficiency; under some conditions the
efficiency gain was equivalent to increasing the sample size by a quarter. We
give an example from our own research where the efficiency gained from
auxiliary variables was equivalent to increasing the sample size by three
quarters, and pushed some estimates from statistical insignificance to
significance. For auxiliary variables to make a difference, there must be a lot
of missing data, some estimates must be near the border of significance, and
the auxiliary variables must be excellent predictors of the missing values.


title: Attractor Control Using Machine Learning

abstract:
  We propose a general strategy for feedback control design of complex
dynamical systems exploiting the nonlinear mechanisms in a systematic
unsupervised manner. These dynamical systems can have a state space of
arbitrary dimension with finite number of actuators (multiple inputs) and
sensors (multiple outputs). The control law maps outputs into inputs and is
optimized with respect to a cost function, containing physics via the dynamical
or statistical properties of the attractor to be controlled. Thus, we are
capable of exploiting nonlinear mechanisms, e.g. chaos or frequency cross-talk,
serving the control objective. This optimization is based on genetic
programming, a branch of machine learning. This machine learning control is
successfully applied to the stabilization of nonlinearly coupled oscillators
and maximization of Lyapunov exponent of a forced Lorenz system. We foresee
potential applications to most nonlinear multiple inputs/multiple outputs
control problems, particulary in experiments.


title: Site-Selective Electronic Correlation in alpha-Plutonium Metal

abstract:
  An understanding of the phase diagram of elemental plutonium (Pu) must
include both the effects of the strong directional bonding and the high density
of states of the Pu 5f electrons, as well as how that bonding weakens under the
influence of strong electronic correlations. We present for the first time
electronic-structure calculations of the full 16-atom per unit cell alpha-phase
structure within the framework of density functional theory (DFT) together with
dynamical mean-field theory (DMFT). Our calculations demonstrate that Pu atoms
sitting on different sites within the alpha-Pu crystal structure have a
strongly varying site dependence of the localization-delocalization correlation
effects of their 5f electrons and a corresponding effect on the bonding and
electronic properties of this complicated metal. In short, alpha-Pu has the
capacity to simultaneously have multiple degrees of electron
localization/delocalization of Pu 5f electrons within a pure single-element
material.


title: On the $p$-integrality of $A$-hypergeometric series

abstract:
  Let $A$ be a set of $N$ vectors in ${\mathbb Z}^n$ and let $v$ be a vector in
${\mathbb C}^N$ that has minimal negative support for $A$. Such a vector $v$
gives rise to a formal series solution of the $A$-hypergeometric system with
parameter $\beta = Av$. If $v$ lies in ${\mathbb Q}^n$, then this series has
rational coefficients. Let $p$ be a prime number. We characterize those $v$
whose coordinates are rational, $p$-integral, and lie in the closed interval
$[-1,0]$ for which the corresponding normalized series solution has
$p$-integral coefficients.


title:
An Introduction to QBism with an Application to the Locality of Quantum
  Mechanics

abstract:
  We give an introduction to the QBist interpretation of quantum mechanics. We
note that it removes the paradoxes, conundra, and pseudo-problems that have
plagued quantum foundations for the past nine decades. As an example, we show
in detail how it eliminates quantum "nonlocality".


title: GRB 130427A: a Nearby Ordinary Monster

abstract:
  Long-duration Gamma-Ray Bursts (GRBs) are an extremely rare outcome of the
collapse of massive stars, and are typically found in the distant Universe.
Because of its intrinsic luminosity ($L\sim 3 \times 10^{53}$ erg s$^{-1}$) and
its relative proximity ($z=0.34$), GRB 130427A was a unique event that reached
the highest fluence observed in the gamma-ray band. Here we present a
comprehensive multiwavelength view of GRB 130427A with Swift, the 2-m Liverpool
and Faulkes telescopes and by other ground-based facilities, highlighting the
evolution of the burst emission from the prompt to the afterglow phase. The
properties of GRB 130427A are similar to those of the most luminous,
high-redshift GRBs, suggesting that a common central engine is responsible for
producing GRBs in both the contemporary and the early Universe and over the
full range of GRB isotropic energies.


title:
The kinetic Sunyaev-Zel'dovich effect from the diffuse gas in the Local
  Group

abstract:
  Since the Local Group (LG) of galaxies moves with a bulk velocity with
respect to the cosmic microwave background radiation (CMB), free electrons in
its gaseous halo should imprint large-scale non-primordial temperature shifts
in the CMB via the kinetic Sunyaev-Zel'dovich (kSZ) effect. By modeling the
distribution of gas in the LG halo and using its inferred velocity with respect
to the CMB, we calculate the resulting kSZ signal from the diffuse LG medium.
We find that it is dominated by a hot spot $\sim 10^\circ$ in size in the
direction of M31, where the optical depth of free electrons is the greatest. By
performing a correlation analysis, we find no statistical evidence that the kSZ
signal from model of the LG halo is embedded in the CMB temperature map
measured by the Planck satellite. We constrain the amount of mass in the LG
halo by limiting the kSZ temperature shift around the hot spot to be smaller
than the observed temperature shift in the Planck map. We find the tightest
constraints for models where the halo mass is highly concentrated, with the
mass limited to roughly $2.5-5\times 10^{12}$M$_\odot$, but note that halos
with such high concentrations are rare.


title: Positive isotropic curvature and self-duality in dimension 4

abstract:
  We study a positivity condition for the curvature of oriented Riemannian
4-manifolds: The half-$PIC$ condition. It is a slight weakening of the positive
isotropic curvature ($PIC$) condition introduced by M. Micallef and J. Moore.
  We observe that the half-$PIC$ condition is preserved by the Ricci flow and
satisfies a maximality property among all Ricci flow invariant positivity
conditions on the curvature of oriented 4-manifolds.
  We also study some geometric and topological aspects of half-$PIC$ manifolds.