title:
Polarized synchrotron radiation from the Andromeda Galaxy M31 and
  background sources at 350 MHz

abstract:
  Polarization measurements at low radio frequencies allow detection of small
Faraday rotation measures caused by regular magnetic fields in galaxies and in
the foreground of the Milky Way. The galaxy M31 was observed in two overlapping
pointings with the Westerbork Synthesis Radio Telescope (WSRT) resulting in ~4'
resolution in total intensity and linearly polarized emission. The frequency
range 310-376 MHz was covered by 1024 channels which allowed the application of
RM synthesis. We derived a data cube in Faraday depth and compared two
symmetric ranges of negative and positive Faraday depths. This new method
avoids the range of high instrumental polarization and allows the detection of
very low degrees of polarization. For the first time, diffuse polarized
emission from a nearby galaxy is detected below 1 GHz. The degree of
polarization is only 0.21 +/- 0.05 %, consistent with extrapolation of internal
depolarization from data at higher radio frequency. A catalogue of 33 polarized
sources and their Faraday rotation in the M31 field is presented. Their average
depolarization is DP(90,20) = 0.14 +/- 0.02, 7 times stronger depolarized than
at 1.4 GHz. We argue that this strong depolarization originates within the
sources, e.g. in their radio lobes, or in intervening galaxies on the line of
sight. On the other hand, the Faraday rotation of the sources is mostly
produced in the foreground of the Milky Way and varies significantly across the
~9 square degree M31 field. As expected, polarized emission from M31 and
extragalactic background sources is much weaker at low frequencies compared to
the GHz range. Future observations with LOFAR, with high sensitivity and high
angular resolution to reduce depolarization, may reveal diffuse polarization
from the outer disks and halos of galaxies.


title: New Results on Neutrino Magnetic Moments and on Democratic Neutrinos

abstract:
  I discuss the two separate issues on neutrino physics. First, the new bounds
on tensorial couplings of neutrinos to charged fermions from the existing
limits on neutrino transition magnetic moments. Second, explanation of the
atmospheric and solar neutrino data in the democratic neutrino theory with only
one free parameter (in the leading order), using the effect of incoherence.


title:
Dynamic Interactions between Oscillating Cantilevers: Nanomechanical
  Modulation using Surface Forces

abstract:
  Dynamic interactions between two oscillating micromechanical cantilevers are
studied. In the experiment, the tip of a high-frequency cantilever is
positioned near the surface of a second low-frequency cantilever. Due to the
highly nonlinear interaction forces between the two surfaces, thermal
oscillations of the low-frequency cantilever modulate the driven oscillations
of the high-frequency cantilever. The dissipations and the frequencies of the
two cantilevers are shown to be coupled, and a simple model for the
interactions is presented. The interactions studied here may be useful for the
design of future micro and nanoelectromechanical systems for mechanical signal
processing; they may also help realize coupled mechanical modes for experiments
in non-linear dynamics.


title: Shapovalov determinant for loop superalgebras

abstract:
  Let a given finite dimensional simple Lie superalgebra g possess an even
invariant non-degenerate supersymmetric bilinear form. We show how to recover
the quadratic Casimir element for the Kac-Moody superalgebra related to the
loop superalgebra with values in g from the quadratic Casimir element for g.
Our main tool here is an explicit Wick normal form of the even quadratic
Casimir operator for the Kac--Moody superalgebra associated with g; this Wick
normal form is of independent interest.
  If g possesses an odd invariant supersymmetric bilinear form we compute the
cubic Casimir element.
  In addition to the cases of Lie superalgebras g(A) with Cartan matrix A for
which the answer was known, we consider the Poisson Lie superalgebra poi(0|n)
and the related Kac--Moody superalgebra.


title: Learning Based Uplink Interference Management in 4G LTE Cellular Systems

abstract:
  LTEs uplink (UL) efficiency critically depends on how the interference across
different cells is controlled. The unique characteristics of LTEs modulation
and UL resource assignment poses considerable challenges in achieving this goal
because most LTE deployments have 1:1 frequency re-use, and the uplink
interference can vary considerably across successive time slots. In this work,
we propose LeAP, a measurement data driven machine learning paradigm for power
control to manage up-link interference in LTE. The data driven approach has the
inherent advantage that the solution adapts based on network traffic,
propagation and network topology, that is increasingly heterogeneous with
multiple cell-overlays. LeAP system design consists of the following
components: (i) design of user equipment (UE) measurement statistics that are
succinct, yet expressive enough to capture the network dynamics, and (ii)
design of two learning based algorithms that use the reported measurements to
set the power control parameters and optimize the network performance. LeAP is
standards compliant and can be implemented in centralized SON (self organized
networking) server resource (cloud). We perform extensive evaluations using
radio network plans from real LTE network operational in a major metro area in
United States. Our results show that, compared to existing approaches, LeAP
provides a 4.9x gain in the 20th percentile of user data rate, and 3.25x gain
in median data rate.


title:
An Overview of the Relationship between Group Theory and Representation
  Theory to the Special Functions in Mathematical Physics

abstract:
  Advances in mathematical physics during the 20th century led to the discovery
of a relationship between group theory and representation theory with the
theory of special functions. Specifically, it was discovered that many of the
special functions are (1) specific matrix elements of matrix representations of
Lie groups, and (2) basis functions of operator representations of Lie
algebras. By viewing the special functions in this way, it is possible to
derive many of their properties that were originally discovered using classical
analysis, such as generating functions, differential relations, and recursion
relations. This relationship is of interest to physicists due to the fact that
many of the common special functions, such as Hermite polynomials and Bessel
functions, are related to remarkably simple Lie groups used in physics.
Unfortunately, much of the literature on this subject remains inaccessible to
undergraduate students. The purpose of this project is to research the existing
literature and to organize the results, presenting the information in a way
that can be understood at the undergraduate level. The primary objects of study
will be the Heisenberg group and its relationship to the Hermite polynomials,
as well as the Euclidean group in the plane and its relationship to the Bessel
functions. The ultimate goal is to make the results relevant for undergraduate
students who have studied quantum mechanics.


title: Forbidden vertices

abstract:
  In this work, we introduce and study the forbidden-vertices problem. Given a
polytope P and a subset X of its vertices, we study the complexity of linear
optimization over the subset of vertices of P that are not contained in X. This
problem is closely related to finding the k-best basic solutions to a linear
problem. We show that the complexity of the problem changes significantly
depending on the encoding of both P and X. We provide additional tractability
results and extended formulations when P has binary vertices only. Some
applications and extensions to integral polytopes are discussed.


title: Finding knowledge paths among scientific disciplines

abstract:
  This paper discovers patterns of knowledge dissemination among scientific
disciplines. While the transfer of knowledge is largely unobservable, citations
from one discipline to another have been proven to be an effective proxy to
study disciplinary knowledge flow. This study constructs a knowledge flow
network in that a node represents a Journal Citation Report subject category
and a link denotes the citations from one subject category to another. Using
the concept of shortest path, several quantitative measurements are proposed
and applied to a knowledge flow network. Based on an examination of subject
categories in Journal Citation Report, this paper finds that social science
domains tend to be more self-contained and thus it is more difficult for
knowledge from other domains to flow into them; at the same time, knowledge
from science domains, such as biomedicine-, chemistry-, and physics-related
domains can access and be accessed by other domains more easily. This paper
also finds that social science domains are more disunified than science
domains, as three fifths of the knowledge paths from one social science domain
to another need at least one science domain to serve as an intermediate. This
paper contributes to discussions on disciplinarity and interdisciplinarity by
providing empirical analysis.


title: Hopf-Lax formula and generalized characteristics

abstract:
  We study some differential properties of viscosity solution for Hamilton -
Jacobi equations defined by Hopf-Lax formula $u(t,x)=\min_{y\in \R^n}
\big\{\sigma (y)+tH^*\big (\frac {x-y}{t}\big)\big \}.$ A generalized form of
characteristics of the Cauchy problems is taken into account the context. Then
we examine the strip of differentiability of the viscosity solution given by
the function $u(t,x).$


title: Trapping of ultra cold atoms in a 3He/4He dilution refrigerator

abstract:
  We describe the preparation of ultra cold atomic clouds in a dilution
refrigerator. The closed cycle 3He/4He cryostat was custom made to provide
optical access for laser cooling, optical manipulation and detection of atoms.
We show that the cryostat meets the requirements for cold atom experiments,
specifically in terms of operating a magneto-optical trap, magnetic traps and
magnetic transport under ultra high vacuum conditions. The presented system is
a step towards the creation of a quantum hybrid system combining ultra cold
atoms and solid state quantum devices.


title: The minimum number of nonnegative edges in hypergraphs

abstract:
  An r-unform n-vertex hypergraph H is said to have the
Manickam-Mikl\'os-Singhi (MMS) property if for every assignment of weights to
its vertices with nonnegative sum, the number of edges whose total weight is
nonnegative is at least the minimum degree of H. In this paper we show that for
n>10r^3, every r-uniform n-vertex hypergraph with equal codegrees has the MMS
property, and the bound on n is essentially tight up to a constant factor. This
result has two immediate corollaries. First it shows that every set of n>10k^3
real numbers with nonnegative sum has at least $\binom{n-1}{k-1}$ nonnegative
k-sums, verifying the Manickam-Mikl\'os-Singhi conjecture for this range. More
importantly, it implies the vector space Manickam-Mikl\'os-Singhi conjecture
which states that for n >= 4k and any weighting on the 1-dimensional subspaces
of F_q^n with nonnegative sum, the number of nonnegative k-dimensional
subspaces is at least ${n-1 \brack k-1}_q$. We also discuss two additional
generalizations, which can be regarded as analogues of the Erd\H{o}s-Ko-Rado
theorem on k-intersecting families.


title:
On reduction of the wave-packet, decoherence, irreversibility and the
  second law of thermodynamics

abstract:
  We prove a quantum version of the second law of thermodynamics: the (quantum)
Boltzmann entropy increases if the initial (zero time) density matrix
decoheres, a condition generally satisfied in Nature. It is illustrated by a
model of wave-packet reduction, the Coleman-Hepp model, along the framework
introduced by Sewell in his approach to the quantum measurement problem.
Further models illustrate the monotonic-versus-non-monotonic behavior of the
quantum Boltzmann entropy in time. As a last closely related topic,
decoherence, which was shown by Narnhofer and Thirring to enforce macroscopic
purity in the case of quantum K systems, is analysed within a different class
of quantum chaotic systems, viz. the quantum Anosov models as defined by Emch,
Narnhofer, Sewell and Thirring.
  A review of the concept of quantum Boltzmann entropy, as well as of some of
the rigorous approaches to the quantum measurement problem within the framework
of Schr\"{o}dinger dynamics, is given, together with an overview of the C*
algebra approach, which encompasses the relevant notions and definitions in a
comprehensive way.


title: Remark on Weil's conjectures

abstract:
  We introduce a cohomology theory for a class of projective varieties over a
finite field coming from the canonical trace on a C*-algebra attached to the
variety. Using the cohomology, we prove the rationality, functional equation
and the Betti numbers conjectures for the zeta function of the variety.


title: Periodic minimal surfaces in semidirect products

abstract:
  In this paper we prove existence of complete minimal surfaces in some metric
semidirect products. These surfaces are similar to the doubly and singly
periodic Scherk minimal surfaces in $\mathbb R^3$. In particular, we obtain
these surfaces in the Heisenberg space with its canonical metric, and in Sol3
with a one-parameter family of non-isometric metrics.


title: Magnetized Gas in the Smith High Velocity Cloud

abstract:
  We report the first detection of magnetic fields associated with the Smith
High Velocity Cloud. We use a catalog of Faraday rotation measures towards
extragalactic radio sources behind the Smith Cloud, new HI observations from
the Green Bank Telescope, and a spectroscopic map of H{\alpha} from the
Wisconsin H-Alpha Mapper Northern Sky Survey. There are enhancements in
rotation measure of approximately 100 rad m^(-2) which are generally well
correlated with decelerated H{\alpha} emission. We estimate a lower limit on
the line-of-sight component of the field of approximately 8 {\mu}G along a
decelerated filament; this is a lower limit due to our assumptions about the
geometry. No RM excess is evident in sightlines dominated by HI or H{\alpha} at
the velocity of the Smith Cloud. The smooth H{\alpha} morphology of the
emission at the Smith Cloud velocity suggests photoionization by the Galactic
ionizing radiation field as the dominant ionization mechanism, while the
filamentary morphology and high (approximately 1 Rayleigh) H{\alpha} intensity
of the lower-velocity magnetized ionized gas suggests an ionization process
associated with shocks due to interaction with the Galactic interstellar
medium. The presence of the magnetic field may contribute to the survival of
high velocity clouds like the Smith Cloud as they move from the Galactic halo
to the disk. We expect these data to provide a test for magnetohydrodynamic
simulations of infalling gas.


title:
Sneaking Up On The Criegee Intermediate From Below: Predicted
  Photoelectron Spectrum Of The CH_2OO^- Anion And W3-F12 Electron Affinity Of
  CH_2OO

abstract:
  High level ab initio calculations were undertaken on the CH$_2$OO anion and
neutral species to predict the electron affinity and anion photoelectron
spectrum. The electron affinity of CH$_2$OO, 0.567 eV, and barrier height for
dissociation of CH$_2$OO$^-$ to O$^-$ and CH$_2$O, 16.5 kJ mol$^{-1}$, are
obtained by means of the W3-F12 thermochemical protocol. Two major geometric
differences between the anion and neutral, being the dihedral angle of the
terminal hydrogen atoms with respect to C-O-O plane, and the O-O bond length,
are reflected in the predicted spectrum as pronounced vibrational progressions.


title:
Effective Strange Quark/Antiquark Masses from the Chiral Soliton Models
  for Baryons

abstract:
  The effective strange quark and antiquark masses are estimated from the
chiral soliton approach (CSA) results for the spectrum of exotic and nonexotic
baryons. There are problems when one tries to project results of the CSA on the
simple quark models (QM): the parameter in $1/N_c$ expansion is so large for
the case of the baryon spectrum that extrapolation to the real $N_c=3$ world is
not possible; rigid (as well soft) rotator model and the bound state model
coincide in the first two orders in $1/N_c$, but differ in the next orders.
There is correspondence of the CSA and simple QM predictions for pentaquarks
(PQ) spectra in negative $S$ sector of the $\{27\}$ and $\{35\}$-plets: the
effective mass of strange quark is about $135 -130\,MeV$, slightly smaller for
$\{35\}$. For positive strangeness components the link between CSA and QM
requires strong dependence of the effective $\bar{s}$ mass on particular SU(3)
multiplet. The SU(3) configuration mixing is important, it pushes the spectrum
towards the simplistic model (with equal masses of the strange quark and
antiquark), and explanation of this nice property is lacking still. The success
of the CSA in describing many properties of baryons and light nuclei
(hypernuclei) means that predictions of pentaquark states should be considered
seriously. Existence of PQ by itself is without any doubt, although very narrow
PQ may not exist. Wide, even very wide PQ should exist, therefore, searches for
PQ remain to be an actual task.


title:
Opposite charged two-body system of identical counter-rotating black
  holes

abstract:
  A 4-parametric exact solution describing a two-body system of identical
Kerr-Newman counter-rotating black holes endowed with opposite
electric/magnetic charges is presented. The axis conditions are solved in order
to really describe two black holes separated by a massless strut. Moreover, the
explicit form of the horizon half length parameter sigma in terms of physical
Komar parameters, i.e., the Komar mass M, electric charge QE, angular momentum
J, and a coordinate distance R is derived. Additionally, magnetic charges QB
arise from the rotation of electrically charged black holes. As a consequence,
in order to account for the contribution to the mass of the magnetic charge,
the usual Smarr mass formula should be generalized, as it is proposed by A.
Tomimatsu, Prog. Theor. Phys. 72, 73 (1984).


title: Lecture notes on interacting quantum fields in de Sitter space

abstract:
  We discuss peculiarities of quantum fields in de Sitter space on the example
of the self-interacting massive real scalar, minimally coupled to the gravity
background. Non-conformal quantum field theories in de Sitter space show very
special infrared behavior, which is not shared by quantum fields neither in
flat nor in anti-de-Sitter space: in de Sitter space loops are not suppressed
in comparison with tree level contributions because there are strong infrared
corrections. That is true even for massive fields. Our main concern is the
interrelation between these infrared effects, the invariance of the quantum
field theory under the de Sitter isometry and the (in)stability of de Sitter
invariant states (and of dS space itself) under nonsymmetric perturbations.


title: On differential passivity of physical systems

abstract:
  Differential passivity is a property that allows to check with a pointwise
criterion that a system is incrementally passive, a property that is relevant
to study interconnected systems in the context of regulation, synchronization,
and estimation. The paper investigates how restrictive is the property,
focusing on a class of open gradient systems encountered in the coenergy
modeling framework of physical systems, in particular the Brayton-Moser
formalism for nonlinear electrical circuits.


title:
A Discovery of a Candidate Companion to a Transiting System KOI-94: A
  Direct Imaging Study for a Possibility of a False Positive

abstract:
  We report a discovery of a companion candidate around one of {\it Kepler}
Objects of Interest (KOIs), KOI-94, and results of our quantitative
investigation of the possibility that planetary candidates around KOI-94 are
false positives. KOI-94 has a planetary system in which four planetary
detections have been reported by {\it Kepler}, suggesting that this system is
intriguing to study the dynamical evolutions of planets. However, while two of
those detections (KOI-94.01 and 03) have been made robust by previous
observations, the others (KOI-94.02 and 04) are marginal detections, for which
future confirmations with various techniques are required. We have conducted
high-contrast direct imaging observations with Subaru/HiCIAO in $H$ band and
detected a faint object located at a separation of $\sim0.6''$ from KOI-94. The
object has a contrast of $\sim 1\times 10^{-3}$ in $H$ band, and corresponds to
an M type star on the assumption that the object is at the same distance of
KOI-94. Based on our analysis, KOI-94.02 is likely to be a real planet because
of its transit depth, while KOI-94.04 can be a false positive due to the
companion candidate. The success in detecting the companion candidate suggests
that high-contrast direct imaging observations are important keys to examine
false positives of KOIs. On the other hand, our transit light curve reanalyses
lead to a better period estimate of KOI-94.04 than that on the KOI catalogue
and show that the planetary candidate has the same limb darkening parameter
value as the other planetary candidates in the KOI-94 system, suggesting that
KOI-94.04 is also a real planet in the system.


title: Cyclic Subsets and Barnette's Conjecture

abstract:
  In this paper, the concept of cyclic subsets in graph theory is introduced.
An interesting theorem which relates to the collective Hamiltonicity of these
cyclic subsets in graphs is also presented. This paper uses this theorem to
construct an inductive proof of Barnette's long-standing conjecture, which asks
whether every cubic, polyhedral, bipartite graph is Hamiltonian. Finding a
class of graphs that are certain to be Hamiltonian is one of the biggest
unsolved problems in Hamiltonian graph theory today.


title: VEST: abstract vector calculus simplification in Mathematica

abstract:
  We present a new package, VEST (Vector Einstein Summation Tools), that
performs abstract vector calculus computations in Mathematica. Through the use
of index notation, VEST is able to reduce three-dimensional scalar and vector
expressions of a very general type to a well defined standard form. In
addition, utilizing properties of the Levi-Civita symbol, the program can
derive types of multi-term vector identities that are not recognized by
reduction, subsequently applying these to simplify large expressions. In a
companion paper (Burby et al., 2013), we employ VEST in the automation of the
calculation of high-order Lagrangians for the single particle guiding center
system in plasma physics, a computation which illustrates its ability to handle
very large expressions. VEST has been designed to be simple and intuitive to
use, both for basic checking of work and more involved computations.


title:
Group automorphisms with prescribed growth of periodic points, and small
  primes in arithmetic progressions in intervals

abstract:
  We investigate the question of which growth rates are possible for the number
of periodic points of a compact group automorphism. Our arguments involve a
modification of Linnik's Theorem, concerning small prime numbers in arithmetic
progressions which lie in intervals.


title:
Nonlinear macroscopic transport equations in many-body systems from
  microscopic exclusion processes

abstract:
  Describing particle transport at the macroscopic or mesoscopic level in
non-ideal environments poses fundamental theoretical challenges in domains
ranging from inter and intra-cellular transport in biology to diffusion in
porous media. Yet, often the nature of the constraints coming from many-body
interactions or reflecting a complex and confining environment are better
understood and modeled at the microscopic level.
  In this paper we investigate the subtle link between microscopic exclusion
processes and the mean-field equations that ensue from them in the continuum
limit. We derive a generalized nonlinear advection diffusion equation suitable
for describing transport in a inhomogeneous medium in the presence of an
external field. Furthermore, taking inspiration from a recently introduced
exclusion process involving agents with non-zero size, we introduce a modified
diffusion equation appropriate for describing transport in a non-ideal fluid of
$d$-dimensional hard spheres.
  We consider applications of our equations to the problem of diffusion to an
absorbing sphere in a non-ideal self-crowded fluid and to the problem of
gravitational sedimentation. We show that our formalism allows one to recover
known results. Moreover, we introduce the notions of point-like and extended
crowding, which specify distinct routes for obtaining macroscopic transport
equations from microscopic exclusion processes.


title:
Evolution of the temporal and the spectral properties in 2010 and 2011
  outbursts of H 1743-322

abstract:
  The Galactic black hole candidate H~1743-322 exhibited two X-ray outbursts in
rapid succession: one in August 2010 and the other in April 2011. We analyze
archival data of this object from the PCA instrument on board RXTE (2-25 keV
energy band) to study the evolution of its temporal and spectral
characteristics during both the outbursts, and hence to understand the
behavioral change of the accretion flow dynamics associated with the evolution
of the various X-ray features. We study the evolution of QPO frequencies during
the rising and the declining phases of both the outbursts. We successfully fit
the variation of QPO frequency using the Propagating Oscillatory Shock (POS)
model in each of the outbursts and obtain the accretion flow parameters such as
the instantaneous shock locations, the shock velocity and the shock strength.
Based on the degree of importance of the thermal (disk black body) and the
non-thermal (power-law) components of the spectral fit and properties of the
QPO (if present), the entire profiles of the 2010 and 2011 outbursts are
subdivided into four different spectral states: hard, hard-intermediate,
soft-intermediate and soft. We attempt to explain the nature of the outburst
profile (i.e., hardness-intensity diagram) with two different types of mass
accretion flow.


title:
Eshelby-like forces acting on elastic structures: theoretical and
  experimental proof

abstract:
  The Eshelbian (or configurational) force is the main concept of a celebrated
theoretical framework associated with the motion of dislocations and, more in
general, defects in solids. In a similar vein, in an elastic structure where a
(smooth and bilateral) constraint can move and release energy, a force driving
the configuration is generated, which therefore is called by analogy
'Eshelby-like' or 'configurational'. This force (generated by a specific
movable constraint) is derived both via variational calculus and,
independently, through an asymptotic approach. Its action on the elastic
structure is counterintuitive, but is fully substantiated and experimentally
measured on a model structure that we have designed, realized and tested. These
findings open a totally new perspective in the mechanics of deformable
mechanisms, with possible broad applications, even at the nanoscale.


title: Representations of stack triangulations in the plane

abstract:
  Stack triangulations appear as natural objects when defining an increasing
family of triangulations by successive additions of vertices. We consider two
different probability distributions for such objects. We represent, or "draw"
these random stack triangulations in the plane $\R^2$ and study the asymptotic
properties of these drawings, viewed as random compact metric spaces. We also
look at the occupation measure of the vertices, and show that for these two
distributions it converges to some random limit measure.


title: Greedy bases in rank 2 generalized cluster algebras

abstract:
  In this note we extend the notion of greedy bases developed by Lee, Li, and
Zelevinsky to rank two generalized cluster algebras, i.e. binomial exchange
relations are replaced by polynomial exchange relations. In the process we give
a combinatorial construction in terms of a refined notion of compatible pairs
on a maximal Dyck path.


title:
Free products of large random matrices - a short review of recent
  developments

abstract:
  We review methods to calculate eigenvalue distributions of products of large
random matrices. We discuss a generalization of the law of free multiplication
to non-Hermitian matrices and give a couple of examples illustrating how to use
these methods in practice. In particular we calculate eigenvalue densities of
products of Gaussian Hermitian and non-Hermitian matrices including
combinations of GUE and Ginibre matrices.


title: Subgroups and Homology of Extensions of Centralizers of Pro-p Groups

abstract:
  We study asymptotic behavior of the dimensions of the homology groups of
subgroups of finite index in finitely generated subgroups of pro-$p$ extension
of centralizers of free pro-$p$ groups. We also prove group theoretic structure
properties of such pro-$p$ groups that are of independent interest.


title:
Dark matter annihilations and decays after the AMS-02 positron
  measurements

abstract:
  The AMS-02 collaboration has recently presented measurements of excellent
quality of the cosmic electron and positron fluxes as well as the positron
fraction. We use the measurements of the positron flux to derive, for the first
time, limits on the dark matter annihilation cross section and lifetime for
various final states. Working under the well-motivated assumption that a
background positron flux exists from spallations of cosmic rays with the
interstellar medium and from astrophysical sources, we find strong limits on
the dark matter properties which are competitive, although slightly weaker,
than those derived from the positron fraction. Specifically, for dark matter
particles annihilating only into e+ e- or into mu+ mu-, our limits on the
annihilation cross section are stronger than the thermal value when the dark
matter mass is smaller than 100 GeV or 60 GeV, respectively.


title: Complexity of control-affine motion planning

abstract:
  In this paper we study the complexity of the motion planning problem for
control-affine systems. Such complexities are already defined and rather
well-understood in the particular case of nonholonomic (or sub-Riemannian)
systems. Our aim is to generalize these notions and results to systems with a
drift. Accordingly, we present various definitions of complexity, as functions
of the curve that is approximated, and of the precision of the approximation.
Due to the lack of time-rescaling invariance of these systems, we consider
geometric and parametrized curves separately. Then, we give some asymptotic
estimates for these quantities.


title:
Differential form description of the Noether-Lagrange machinery,
  vielbein/gauge-field analogies and energy-momentum complexes

abstract:
  We derive the variational principle and Noether's theorem in generally
covariant field theory in an explicitly coordinate-independent way by means of
the exterior calculus over the space-time manifold. We then focus on the
symmetry of active diffeomorphisms, that is, the pushforwards along the
integral lines of any vector field, and its analogies with internal gauge
symmetries. For instance, it is well known that a class of Noether currents
associated to a gauge symmetry can be obtained by taking the partial derivative
of the Lagrangian with respect to the corresponding gauge field. Here we show
that this relation also holds for the Noether currents associated to
diffeomorphisms and the vielbein, but only if one decomposes all forms in the
vielbein basis. We also relate the diffeomorphism Noether currents to the
matter energy-momentum tensor of General Relativity, to Hamiltonian boundary
terms and to two known energy-momentum complexes of the vielbein.


title: Birational geometry of cluster algebras

abstract:
  We give a geometric interpretation of cluster varieties in terms of blowups
of toric varieties. This enables us to provide, among other results, an
elementary geometric proof of the Laurent phenomenon for cluster algebras (of
geometric type), extend Speyer's example of an upper cluster algebra which is
not finitely generated, and show that the Fock-Goncharov dual basis conjecture
is usually false.


title: Randomized Consensus with Attractive and Repulsive Links

abstract:
  We study convergence properties of a randomized consensus algorithm over a
graph with both attractive and repulsive links. At each time instant, a node is
randomly selected to interact with a random neighbor. Depending on if the link
between the two nodes belongs to a given subgraph of attractive or repulsive
links, the node update follows a standard attractive weighted average or a
repulsive weighted average, respectively. The repulsive update has the opposite
sign of the standard consensus update. In this way, it counteracts the
consensus formation and can be seen as a model of link faults or malicious
attacks in a communication network, or the impact of trust and antagonism in a
social network. Various probabilistic convergence and divergence conditions are
established. A threshold condition for the strength of the repulsive action is
given for convergence in expectation: when the repulsive weight crosses this
threshold value, the algorithm transits from convergence to divergence. An
explicit value of the threshold is derived for classes of attractive and
repulsive graphs. The results show that a single repulsive link can sometimes
drastically change the behavior of the consensus algorithm. They also
explicitly show how the robustness of the consensus algorithm depends on the
size and other properties of the graphs.


title: Interstitial-Boron Solution Strengthened WB$_{3+x}$

abstract:
  By means of variable-composition evolutionary algorithm coupled with density
functional theory and in combination with aberration-corrected high-resolution
transmission electron microscopy experiments, we have studied and characterized
the composition, structure and hardness properties of WB$_{3+x}$ ($x$ $<$ 0.5).
We provide robust evidence for the occurrence of stoichiometric WB$_3$ and
non-stoichiometric WB$_{3+x}$ both crystallizing in the metastable $hP$16
($P6_3/mmc$) structure. No signs for the formation of the highly debated WB$_4$
(both $hP$20 and $hP$10) phases were found. Our results rationalize the
seemingly contradictory high-pressure experimental findings and suggest that
the interstitial boron atom is located in the tungsten layer and vertically
interconnect with four boron atoms, thus forming a typical three-center boron
net with the upper and lower boron layers in a three-dimensional covalent
network, which thereby strengthen the hardness.


title: A Survey on Migration-Selection Models in Population Genetics

abstract:
  This survey focuses on the most important aspects of the mathematical theory
of population genetic models of selection and migration between discrete
niches. Such models are most appropriate if the dispersal distance is short
compared to the scale at which the environment changes, or if the habitat is
fragmented. The general goal of such models is to study the influence of
population subdivision and gene flow among subpopulations on the amount and
pattern of genetic variation maintained. Only deterministic models are treated.
Because space is discrete, they are formulated in terms of systems of nonlinear
difference or differential equations. A central topic is the exploration of the
equilibrium and stability structure under various assumptions on the patterns
of selection and migration. Another important, closely related topic concerns
conditions (necessary or sufficient) for fully polymorphic (internal)
equilibria. First, the theory of one-locus models with two or multiple alleles
is laid out. Then, mostly very recent, developments about multilocus models are
presented. Finally, as an application, analysis and results of an explicit
two-locus model emerging from speciation theory are highlighted.


title: New Examples of Flux Vacua

abstract:
  Type IIB toroidal orientifolds are among the earliest examples of flux vacua.
By applying T-duality, we construct the first examples of massive IIA flux
vacua with Minkowski space-times, along with new examples of type IIA flux
vacua. The backgrounds are surprisingly simple with no four-form flux at all.
They serve as illustrations of the ingredients needed to build type IIA and
massive IIA solutions with scale separation. To check that these backgrounds
are actually solutions, we formulate the complete set of type II supergravity
equations of motion in a very useful form that treats the R-R fields
democratically.


title: Size-dependent same-material tribocharging in insulating grains

abstract:
  Observations of flowing granular matter have suggested that same-material
tribocharging de- pends on particle size, rendering large grains positive and
small ones negative. Models assuming the transfer of trapped electrons can
explain this, but so far have not been validated. Tracking individual grains in
an electric field, we show quantitatively that charge is transferred based on
size between materially identical grains. However, the surface density of
trapped electrons, measured independently by thermoluminescence techniques, is
orders of magnitude too small to account for the scale of charge transferred.
This suggests that another negatively charged species, such as ions, is
responsible.


title: Warped Entanglement Entropy

abstract:
  We study the applicability of the covariant holographic entanglement entropy
proposal to asymptotically warped AdS$_3$ spacetimes with an SL(2,R) x U(1)
isometry. We begin by applying the proposal to locally AdS$_3$ backgrounds
which are written as a real-line fibration over AdS$_2$. We then perturb away
from this geometry by considering a warping parameter $a=1+\delta$ to get an
asymptotically warped AdS$_3$ spacetime and compute the dual entanglement
entropy perturbatively in $\delta$. We find that for large separation in the
fiber coordinate, the entanglement entropy can be computed to all orders in
$\delta$ and takes the universal form appropriate for two-dimensional CFTs. The
warping-dependent central charge thus identified exactly agrees with previous
calculations in the literature. Performing the same perturbative calculations
for the warped BTZ black hole again gives universal two-dimensional CFT
answers, with the left-moving and right-moving temperatures appearing
appropriately in the result.


title:
Plasmonic nanoantennas as integrated coherent perfect absorbers on SOI
  waveguides for modulators and all-optical switches

abstract:
  The performance of plasmonic nanoantenna structures on top of SOI wire
waveguides as coherent perfect absorbers for modulators and all-optical
switches is explored. The absorption, scattering, reflection and transmission
spectra of gold and aluminum nanoantenna-loaded waveguides were calculated by
means of 3D finite-difference time-domain simulations for single waves
propagating along the waveguide, as well as for standing wave scenarios
composed from two counterpropagating waves. The investigated configurations
showed losses of roughly 1% and extinction ratios greater than 25 dB for
modulator and switching applications, as well as plasmon effects such as strong
field enhancement and localization in the nanoantenna region. The proposed
plasmonic coherent perfect absorbers can be utilized for ultracompact
all-optical switches in coherent networks as well as modulators and can find
applications in sensing or in increasing nonlinear effects.


title: The Gravitational-Wave Discovery Space of Pulsar Timing Arrays

abstract:
  Recent years have seen a burgeoning interest in using pulsar timing arrays
(PTAs) as gravitational-wave (GW) detectors. To date, that interest has focused
mainly on three particularly promising source types: supermassive--black-hole
binaries, cosmic strings, and the stochastic background from early-Universe
phase transitions. In this paper, by contrast, our aim is to investigate the
PTA potential for discovering unanticipated sources. We derive significant
constraints on the available discovery space based solely on energetic and
statistical considerations: we show that a PTA detection of GWs at frequencies
above ~3.e-5 Hz would either be an extraordinary coincidence or violate
"cherished beliefs;" we show that for PTAs GW memory can be more detectable
than direct GWs, and that, as we consider events at ever higher redshift, the
memory effect increasingly dominates an event's total signal-to-noise ratio.
The paper includes also a simple analysis of the effects of pulsar red noise in
PTA searches, and a demonstration that the effects of periodic GWs in the 10^-8
-- 10^-4.5 Hz band would not be degenerate with small errors in standard pulsar
parameters (except in a few narrow bands).


title: Effect of Virtual Pairs on the Inter-quark Potential

abstract:
  We use the variational method, in a reformulated Hamiltonian formalism of
QCD, to derive the wave equation for a heavy quark-antiquark system using a
trial state that contains a component with a virtual light quark pair. We
examine the quark-antiquark potential in the non-relativistic limit using an
approximate trial ground-state wave function. We find that the potential
exhibits a confining character due to the inclusion of the virtual pair
component in the trial state.


title:
A fast and versatile QKD system with hardware key distillation and
  wavelength multiplexing

abstract:
  We present a 625 MHz clocked coherent one-way quantum key distribution (QKD)
system which continuously distributes secret keys over an optical fibre link.
To support high secret key rates, we implemented a fast hardware key
distillation engine which allows for key distillation rates up to 4 Mbps in
real time. The system employs wavelength multiplexing in order to run over only
a single optical fibre and is compactly integrated in 19-inch 2U racks. We
optimized the system considering a security analysis that respects
finite-key-size effects, authentication costs, and system errors. Using fast
gated InGaAs single photon detectors, we reliably distribute secret keys with
rates up to 140 kbps and over 25 km of optical fibre, for a security parameter
of 4E-9.


title:
Non mean-field behaviour of critical wetting transition for short-range
  forces

abstract:
  Critical wetting transition for short-range forces in three dimensions
($d=3$) is reinvestigated by means of Monte Carlo simulation. Using anisotropic
finite size scaling approach, as well as approaches that do not rely on finite
size scaling, we show that the critical wetting transition shows clear
deviation from mean-field behaviour. We estimate that the effective critical
exponent $\nu_{\|}^{\textrm{eff}}=1.76\pm 0.08$ for $J/kT=0.35$ and
$\nu_{\|}^{\textrm{eff}}=1.85\pm 0.07$ for $J/kT=0.25$. These values are in
accord with predictions of Parry {\it et al.} [Phys. Rev. Lett. {\bf 100},
136105 (2008)]. We also point out that the anisotropic finite size scaling
approach in $d=3$ requires additional modification in order to reach full
consistency of simulational results.


title: Adaptive and minimax optimal estimation of the tail coefficient

abstract:
  We consider the problem of estimating the tail index $\alpha$ of a
distribution satisfying a $(\alpha, \beta)$ second-order Pareto-type condition,
where \beta is the second-order coefficient. When $\beta$ is available, it was
previously proved that $\alpha$ can be estimated with the oracle rate
$n^{-\beta/(2\beta+1)}$. On the contrary, when $\beta$ is not available,
estimating $\alpha$ with the oracle rate is challenging; so additional
assumptions that imply the estimability of $\beta$ are usually made. In this
paper, we propose an adaptive estimator of $\alpha$, and show that this
estimator attains the rate $(n/\log\log n)^{-\beta/(2\beta+1)}$ without a
priori knowledge of $\beta$ and any additional assumptions. Moreover, we prove
that this $(\log\log n)^{\beta/(2\beta+1)}$ factor is unavoidable by obtaining
the companion lower bound.


title: Quantum computing on encrypted data

abstract:
  The ability to perform computations on encrypted data is a powerful tool for
protecting privacy. Recently, protocols to achieve this on classical computing
systems have been found. Here we present an efficient solution to the quantum
analogue of this problem that enables arbitrary quantum computations to be
carried out on encrypted quantum data. We prove that an untrusted server can
implement a universal set of quantum gates on encrypted quantum bits (qubits)
without learning any information about the inputs, while the client, knowing
the decryption key, can easily decrypt the results of the computation. We
experimentally demonstrate, using single photons and linear optics, the
encryption and decryption scheme on a set of gates sufficient for arbitrary
quantum computations. Because our protocol requires few extra resources
compared to other schemes it can be easily incorporated into the design of
future quantum servers. These results will play a key role in enabling the
development of secure distributed quantum systems.


title: Discovery of nine extended ionized gas clouds in a z=0.4 cluster

abstract:
  From deep H-alpha imaging data of Suprime-Cam/Subaru, we discovered nine
extended ionized gas clouds (EIG) around galaxies in Abell 851 cluster (A851)
at z=0.4. We surveyed 30 x 25 arcmin region, and the EIGs were found only near
the cluster center (<2.3 arcmin ~ 750 kpc). The parent galaxies of the EIGs are
star-forming or post-starburst galaxies, all of which are spectroscopically
confirmed members of the cluster. Four out of the nine parent galaxies show
distortion of stellar distribution in the disk, which can be a sign of recent
interaction, and the interaction may have made EIGs. On the other hand, six
parent galaxies (one overlaps those exhibiting distortion) show H-alpha
emission without stars, which implies a ram pressure stripping.The spe ctrum of
the brightest parent galaxy shows a post-starburst signature, and resembles the
H-alpha stripped galaxies found in the Coma cluster. Meanwhile, two brightest
parent galaxies in A851 are more massive than the EIG parent galaxies in the
Coma cluster. This is consistent with "downsizing" of star-forming galaxies,
though it is still in a statistical fluctuation. We also analyzed Suprime-Cam
data of another z=0.39 cluster, CL0024+17, but found no EIGs. The key
difference between A851 and CL0024+17 would be the existence of a subcluster
colliding with the main body of A851, in which six or seven out of the nine
parent galaxies in A851 exist, and the fraction of EIGs in the subcluster is
significantly higher than the main subcluster of A851 and CL0024+17.


title: Nonlinear Biochemical Signal Processing via Noise Propagation

abstract:
  Single-cell studies often show significant phenotypic variability due to the
stochastic nature of intra-cellular biochemical reactions. When the numbers of
molecules, e.g., transcription factors and regulatory enzymes, are in low
abundance, fluctuations in biochemical activities become significant and such
"noise" can propagate through regulatory cascades in terms of biochemical
reaction networks. Here we develop an intuitive, yet fully quantitative method
for analyzing how noise affects cellular phenotypes based on identifying a
system's nonlinearities and noise propagations. We observe that such noise can
simultaneously enhance sensitivities in one behavioral region while reducing
sensitivities in another. Employing this novel phenomenon we designed three
biochemical signal processing modules: (a) A gene regulatory network that acts
as a concentration detector with both enhanced amplitude and sensitivity. (b) A
non-cooperative positive feedback system, with a graded dose-response in the
deterministic case, that serves as a bistable switch due to noise-induced
bimodality. (c) A noise-induced linear amplifier for gene regulation that
requires no feedback. The methods developed in the present work allow one to
understand and engineer nonlinear biochemical signal processors based on
fluctuation-induced phenotypes.


title: Selected Topics in Random Walk in Random Environment

abstract:
  Random walk in random environment (RWRE) is a fundamental model of
statistical mechanics, describing the movement of a particle in a highly
disordered and inhomogeneous medium as a random walk with random jump
probabilities. It has been introduced in a series of papers by Chernov and
Temkin as a model for DNA chain replication and crystal growth, and also as a
model for turbulent behavior in fluids through a Lorentz gas description by
Sinai. It is a simple but powerful model for a variety of complex large-scale
disordered phenomena arising from fields such as physics, biology and
engineering. While the one-dimensional model is well-understood, in the
multidimensional setting, fundamental questions about the RWRE model have
resisted repeated and persistent attempts to answer them. Two major
complications in this context stem from the loss of the Markov property under
the averaged measure as well as the fact that in dimensions larger than one,
the RWRE is not reversible anymore. In these notes we present a general
overview of the model, with an emphasis on the multidimensional setting and a
more detailed description of recent progress around ballisticity questions.


title:
Fine structure of Surface Relief Gratings: experiment and a generic
  stochastic Monte Carlo model of the photoinduced mass transport in
  azo-polymer

abstract:
  We study experimentally and theoretically a double-peak fine structure of
Surface Relief Gratings in azo-functionalized poly(etherimide). For the
theoretical analysis we develop a stochastic Monte Carlo model for photoinduced
mass transport in azobenzene functionalized polymer matrix. The long
sought-after transport of polymer chains from bright to dark places of the
illumination pattern is demonstrated and characterized, various scenarios for
the intertwined processes of build-up of density and SRG gratings are examined.
Model predicts that for some azo-functionalized materials double-peak SRG
maxima can develop in the permanent, quasi-permanent or transient regimes.


title:
Measurement of the muon charge asymmetry in ppbar to W + X to mu nu + X
  events at sqrt{s} = 1.96 TeV

abstract:
  We present a measurement of the muon charge asymmetry from the decay of the
$W$ boson via W to mu nu using 7.3 fb^{-1} of integrated luminosity collected
with the D0 detector at the Fermilab Tevatron Collider at sqrt{s} = 1.96 TeV.
The muon charge asymmetry is presented in two kinematic regions in muon
transverse momentum and event missing transverse energy: (p^{\mu}_{T} > 25 GeV,
\met > 25 GeV) and (p^{\mu}_{T} > 35 GeV, \met > 35 GeV). The measured
asymmetries are compared with theory predictions made using three parton
distribution function sets. The predictions do not describe the data well for
p^{\mu}_{T} > 35 GeV, \met > 35 GeV, and larger values of muon pseudorapidity.


title:
Da investiga\c{c}\~ao sobre a natureza da luz \`a relatividade especial:
  notas de aula

abstract:
  It is shown as experiments and theories about the nature of light led to the
special theory of relativity. The most important facts for the emergence of the
theory proposed by Einstein in 1905 are presented.


title: Maximizing submodular functions using probabilistic graphical models

abstract:
  We consider the problem of maximizing submodular functions; while this
problem is known to be NP-hard, several numerically efficient local search
techniques with approximation guarantees are available. In this paper, we
propose a novel convex relaxation which is based on the relationship between
submodular functions, entropies and probabilistic graphical models. In a
graphical model, the entropy of the joint distribution decomposes as a sum of
marginal entropies of subsets of variables; moreover, for any distribution, the
entropy of the closest distribution factorizing in the graphical model provides
an bound on the entropy. For directed graphical models, this last property
turns out to be a direct consequence of the submodularity of the entropy
function, and allows the generalization of graphical-model-based upper bounds
to any submodular functions. These upper bounds may then be jointly maximized
with respect to a set, while minimized with respect to the graph, leading to a
convex variational inference scheme for maximizing submodular functions, based
on outer approximations of the marginal polytope and maximum likelihood bounded
treewidth structures. By considering graphs of increasing treewidths, we may
then explore the trade-off between computational complexity and tightness of
the relaxation. We also present extensions to constrained problems and
maximizing the difference of submodular functions, which include all possible
set functions.


title:
Effect of Disorder in the Frustrated Ising FCC Antiferromagnet: Phase
  Diagram and Stretched Exponential Relaxation

abstract:
  We study the phase transition in a face-centered-cubic antiferromagnet with
Ising spins as a function of the concentration $p$ of ferromagnetic bonds
randomly introduced into the system. Such a model describes the spin-glass
phase at strong bond disorder. Using the standard Monte Carlo simulation and
the powerful Wang-Landau flat-histogram method, we carry out in this work
intensive simulations over the whole range of $p$. We show that the first-order
transition disappears with a tiny amount of ferromagnetic bonds, namely $p\sim
0.01$, in agreement with theories and simulations on other 3D models. The
antiferromagnetic long-range order is also destroyed with a very small $p$
($\simeq 5%$). With increasing $p$, the system changes into a spin glass and
then to a ferromagnetic phase when $p>0.65$. The phase diagram in the space
($T_c,p$) shows an asymmetry, unlike the case of the $\pm J$ Ising spin glass
on the simple cubic lattice. We calculate the relaxation time around the
spin-glass transition temperature and we show that the spin autocorrelation
follows a stretched exponential relaxation law where the factor $b$ is equal to
$\simeq 1/3$ at the transition as suggested by the percolation-based theory.
This value is in agreement with experiments performed on various spin glasses
and with Monte Carlo simulations on different SG models.


title: Non-Linear Localized Modes Give Rise to a Reflective Optical Limiter

abstract:
  Optical limiters are designed to transmit low intensity light, while blocking
the light with excessively high intensity. A typical passive limiter absorbs
excessive electromagnetic energy, which can cause its overheating and
destruction. We propose the concept of a layered reflective limiter based on
resonance transmission via a non-linear localized mode. Such a limiter does not
absorb the high level radiation, but rather reflects it back to space.
Importantly, the total reflection occurs within a broad frequency range and for
an arbitrary direction of incidence. The same concept can be applied to
infrared and microwave frequencies.


title:
Semimetallic Two-Dimensional Boron Allotrope with Massless Dirac
  Fermions

abstract:
  It has been widely accepted that planar boron structures, composed of
triangular and hexagonal motifs are the most stable two dimensional (2D) phases
and likely precursors for boron nanostructures. Here we predict, based on ab
initio evolutionary structure search, novel 2D boron structure with non-zero
thickness, which is considerably, by 50 meV/atom lower in energy than the
recently proposed alpha-sheet structure and its analogues. In particular, this
phase is identified for the first time to have a distorted Dirac cone, after
graphene and silicene the third elemental material with massless Dirac
fermions. The buckling and coupling between the two sublattices not only
enhance the energetic stability, but also are the key factors for the emergence
of the distorted Dirac cone.


title: Mine Blood Donors Information through Improved K-Means Clustering

abstract:
  The number of accidents and health diseases which are increasing at an
alarming rate are resulting in a huge increase in the demand for blood. There
is a necessity for the organized analysis of the blood donor database or blood
banks repositories. Clustering analysis is one of the data mining applications
and K-means clustering algorithm is the fundamental algorithm for modern
clustering techniques. K-means clustering algorithm is traditional approach and
iterative algorithm. At every iteration, it attempts to find the distance from
the centroid of each cluster to each and every data point. This paper gives the
improvement to the original k-means algorithm by improving the initial
centroids with distribution of data. Results and discussions show that improved
K-means algorithm produces accurate clusters in less computation time to find
the donors information.


title:
An interpolation technique towards the subpolynomial constants in the
  multilinear Bohnenblust-Hille inequality

abstract:
  We show that a recent interpolative new proof of the Bohnenblust--Hille
inequality, when suitably handled, recovers its best known constants. This
seems to be unexpectedly surprising since the known interpolative approaches
only provide constants having exponential growth. This preprint is no longer an
independent submission, it is now contained in the preprint arXiv 1310.2834.


title:
The expected characteristic and permanental polynomials of the random
  Gram matrix

abstract:
  A t by n random matrix A is formed by sampling n independent random column
vectors, each containing t components. The random Gram matrix of size n, G_n,
contains the dot products between all pairs of column vectors in the randomly
generated matrix A; that is, G_n = transpose(A) A. The matrix G_n has
characteristic roots coinciding with the singular values of A. Furthermore, the
sequences det(G_i) and per(G_i) (for i = 0, 1, ..., n) are factors that
comprise the expected coefficients of the characteristic and permanental
polynomials of G_n. We prove theorems that relate the generating functions and
recursions for the traces of matrix powers, expected characteristic
coefficients, expected determinants E(det(G_n)), and expected permanents
E(per(G_n)) in terms of each other. Using the derived recursions, we exhibit
the efficient computation of the expected determinant and expected permanent of
a random Gram matrix G_n, formed according to any underlying distribution.
These theoretical results may be used both to speed up numerical algorithms and
to investigate the numerical properties of the expected characteristic and
permanental coefficients of any matrix comprised of independently sampled
columns.


title: Predicting unobserved exposures from seasonal epidemic data

abstract:
  We consider a stochastic Susceptible-Exposed-Infected-Recovered (SEIR)
epidemiological model with a contact rate that fluctuates seasonally. Through
the use of a nonlinear, stochastic projection, we are able to analytically
determine the lower dimensional manifold on which the deterministic and
stochastic dynamics correctly interact. Our method produces a low dimensional
stochastic model that captures the same timing of disease outbreak and the same
amplitude and phase of recurrent behavior seen in the high dimensional model.
Given seasonal epidemic data consisting of the number of infectious
individuals, our method enables a data-based model prediction of the number of
unobserved exposed individuals over very long times.


title: The Caloron Correspondence and Odd Differential K-theory

abstract:
  The caloron correspondence is a tool that gives an equivalence between
principal $G$-bundles based over the manifold $M \times S^1$ and principal
$LG$-bundles on $M$, where $LG$ is the Fr\'echet Lie group of smooth loops in
the Lie group $G$. This thesis uses the caloron correspondence to construct
certain differential forms called "string potentials" that play the same role
as Chern-Simons forms for loop group bundles. Following their construction, the
string potentials are used to define degree 1 differential characteristic
classes for $\Omega U(n)$-bundles.
  The notion of an "$\Omega$ vector bundle" is introduced and a caloron
correspondence is developed for these objects. Finally, string potentials and
$\Omega$ vector bundles are used to define an $\Omega$ bundle version of the
structured vector bundles of Simons--Sullivan. The "$\Omega$ model" of odd
differential $K$-theory is constructed using these objects and an elementary
differential extension of odd $K$-theory due to Tradler et al.


title: A Feasibility Study of an e+e- Ring Collider for Higgs Factory

abstract:
  A ring-based Higgs factory with a center-of-mass energy of 240 GeV residing
in the existing LEP tunnel is studied at a level of concrete lattice. We found
that low-emittance lattice is essential to mitigate the effect of beamstrahlung
on the beam lifetime. To achieve a luminosity of $1.0\times10^{34}{\rm
cm}^{-2}{\rm s}^{-1}$, we simplified final focusing system and improved its
momentum aperture by a factor of 5 to 2.5%.


title: Microlensing of Quasar UV Iron Emission

abstract:
  We measure the differential microlensing of the UV Fe II and Fe III emission
line blends between 14 quasar image pairs in 13 gravitational lenses. We find
that the UV iron emission is strongly microlensed in 4 cases with amplitudes
comparable to that of the continuum. Statistically modeling the magnifications
we infer a typical size of r ~ 4*sqrt(M/Msun) light-days for the Fe line
emitting regions which is comparable to the size of the region generating the
UV continuum (3 ~ 7 light-days). This may indicate that a significant part of
the UV Fe II and Fe III emission originates in the quasar accretion disk.


title: Obscuration effects in Super-Soft-Source X-ray spectra

abstract:
  Super-Soft-Source (SSS) X-ray spectra are blackbody-like spectra with
effective temperatures ~3-7x10^5 K and luminosities of 10^{35-38} erg/s. SSS
grating spectra display atmospheric absorption lines. Radiation transport
atmosphere models can be used to derive physical parameters, but more
sophisticated models are required. We bypass the complications of spectral
models and concentrate on the data in a comparative, qualitative study. We
inspect all available X-ray grating SSS spectra to determine systematic,
model-independent trends. We use comparative plots of spectra of different
systems to find common and different features. The results are interpreted in
the context of system parameters obtained from the literature. We find two
distinct types of SSS spectra which we name SSa and SSe. Their main
observational characteristics are either clearly visible absorption lines or
emission lines, respectively, while both types contain atmospheric continuum
emission. SSe may be obscured SSa systems, which is supported by similarities
between SSe and SSa with obscured and unobscured AGN, respectively. Further, we
find all known or suspected high-inclination systems to emit permanently in an
SSe state. Some sources are found to transition between SSa and SSe states,
becoming SSe when fainter. SSS spectra are subject to various occultation
processes. In Cal 87, the accretion disc blocks the central hot source when
viewed edge on. In novae, the accretion disc may have been destroyed during the
initial explosion but could have reformed by the time of the SSS phase. In
addition, clumpy ejecta may lead to temporary obscuration events. The emission
lines originate from reprocessed emission in the accretion disc, its wind or
further out in clumpy ejecta while Thomson scattering allows continuum emission
to be visible also during total obscuration of the central hot source.


title:
An unproven inequality which solves three famous problems in Number
  Theory

abstract:
  We write x |P y to denote that x is a prime number and x divides y. For a
positive integer n, let \beta(n) denote the smallest non-negative integer b
such that for each system S \subseteq {x_i+1=x_j, x_i \cdot x_i=x_j, x_i |P
x_j: i,j \in {1,...,n}} with a finite number of solutions in integers
x_1,...,x_n, all these solutions belong to[-b,b]^n. We prove: (1) for each
integer n \geq 9, the inequality \beta(n)<(2^{2^{n-4}}+3)^{2^{n-4}}+1 implies
that 2^{2^{n-4}}+1 is composite, (2) the inequality \beta(9)<(2^{32}+3)^{32}+1
implies that there are infinitely many integers n such that both n^2+1 and
n^2+3 are prime.


title:
Electroweak and QCD Radiative Corrections to Drell-Yan Process for
  Experiments at the Large Hadron Collider

abstract:
  Next-to-leading order electroweak and QCD radiative corrections to the
Drell-Yan process with high dimuon masses for experiments CMS LHC at CERN have
been studied in fully differential form. The FORTRAN code READY for numerical
analysis of Drell-Yan observables has been presented. The radiative corrections
are found to become significant for CMS LHC experiment setup.


title: Mode Invisibility and Single Photon Detection

abstract:
  We propose a technique to probe the quantum state of light in an optical
cavity without significantly altering it. We minimize the interaction of the
probe with the field by arranging a setting where the largest contribution to
the transition probability is cancelled. We show that we obtain a very good
resolution to measure photon population differences between two given Fock
states by means of atomic interferometry.


title: Toward the excited isoscalar meson spectrum from lattice QCD

abstract:
  We report on the extraction of an excited spectrum of isoscalar mesons using
lattice QCD. Calculations on several lattice volumes are performed with a range
of light quark masses corresponding to pion masses down to about 400 MeV. The
distillation method enables us to evaluate the required disconnected
contributions with high statistical precision for a large number of meson
interpolating fields. We find relatively little mixing between light and
strange in most JPC channels; one notable exception is the pseudoscalar sector
where the approximate SU(3)F octet, singlet structure of the {\eta}, {\eta}' is
reproduced. We extract exotic JPC states, identified as hybrid mesons in which
an excited gluonic field is coupled to a color-octet qqbar pair, along with
non-exotic hybrid mesons embedded in a qqbar-like spectrum.


title:
Contextual Focus: A Cognitive Explanation for the Cultural Revolution of
  the Middle/Upper Paleolithic

abstract:
  Many elements of culture made their first appearance in the Upper
Paleolithic. Previous hypotheses put forth to explain this unprecedented burst
of creativity are found wanting. Examination of the psychological basis of
creativity leads to the suggestion that it resulted from the onset of
contextual focus: the capacity to focus or defocus attention in response to the
situation, thereby shifting between analytic and associative modes of thought.
New ideas germinate in a defocused state in which one is receptive to the
possible relevance of many dimensions of a situation. They are refined in a
focused state, conducive to filtering out irrelevant dimensions and condensing
relevant ones.


title:
On superactivation of zero-error capacities and reversibility of a
  quantum channel

abstract:
  We propose examples of low dimensional quantum channels demonstrating
different forms of superactivation of one-shot zero-error capacities, in
particular, the extreme superactivation (this complements the recent result of
T.S.Cubitt and G.Smith).
  We also describe classes of quantum channels whose zero-error classical and
quantum capacities cannot be superactivated.
  We consider implications of the superactivation of one-shot zero-error
capacities to analysis of reversibility of a tensor-product channel with
respect to families of pure states.
  Our approach based on the notions of complementary channel and of transitive
subspace of operators makes it possible to study the superactivation effects
for infinite-dimensional channels as well.


title: Attractor Solutions in Scalar-Field Cosmology

abstract:
  Models of cosmological scalar fields often feature "attractor solutions" to
which the system evolves for a wide range of initial conditions. There is some
tension between this well-known fact and another well-known fact: Liouville's
theorem forbids true attractor behavior in a Hamiltonian system. In universes
with vanishing spatial curvature, the field variables (\phi,\dot\phi) specify
the system completely, defining an effective phase space. We investigate
whether one can define a unique conserved measure on this effective phase
space, showing that it exists for m^2\phi^2 potentials and deriving conditions
for its existence in more general theories. We show that apparent attractors
are places where this conserved measure diverges in the (\phi,\dot\phi)
variables and suggest a physical understanding of attractor behavior that is
compatible with Liouville's theorem.


title: Bounded convergence theorems

abstract:
  There are presented certain results on extending continuous linear operators
defined on spaces of E-valued continuous functions (defined on a compact
Hausdorff space X) to linear operators defined on spaces of E-valued measurable
functions in a way such that uniformly bounded sequences of functions that
converge pointwise in the weak (or norm) topology of E are sent to sequences
that converge in the weak, norm or weak* topology of the target space. As an
application, a new description of uniform closures of convex subsets of C(X,E)
is given. Also new and strong results on integral representations of continuous
linear operators defined on C(X,E) are presented. A new classes of vector
measures are introduced and various bounded convergence theorems for them are
proved.


title: Notes on maximal slices of five-dimensional black holes

abstract:
  We consider maximal slices of the Myers-Perry black hole, the doubly spinning
black ring, and the Black Saturn solution. These slices are complete,
asymptotically flat Riemannian manifolds with inner boundaries corresponding to
black hole horizons. Although these spaces are simply connected as a
consequence of topological censorship, they have non-trivial topology. In this
note we investigate the question of whether the topology of spatial sections of
the horizon uniquely determines the topology of the maximal slices. We show
that the horizon determines the homological invariants of the slice under
certain conditions. The homological analysis is extended to black holes for
which explicit geometries are not yet known. We believe that these results
could provide insights in the context of proving existence of deformations of
this initial data. For the topological slices of the doubly spinning black ring
and the Black Saturn we compute the homotopy groups up to dimension 3 and show
that their 4-dimensional homotopy group is not trivial.


title: Morphogenesis at criticality?

abstract:
  Spatial patterns in the early fruit fly embryo emerge from a network of
interactions among transcription factors, the gap genes, driven by maternal
inputs. Such networks can exhibit many qualitatively different behaviors,
separated by critical surfaces. At criticality, we should observe strong
correlations in the fluctuations of different genes around their mean
expression levels, a slowing of the dynamics along some but not all directions
in the space of possible expression levels, correlations of expression
fluctuations over long distances in the embryo, and departures from a Gaussian
distribution of these fluctuations. Analysis of recent experiments on the gap
genes shows that all these signatures are observed, and that the different
signatures are related in ways predicted by theory. While there might be other
explanations for these individual phenomena, the confluence of evidence
suggests that this genetic network is tuned to criticality.

categories: q-bio.MN cond-mat.dis-nn cond-mat.stat-mech nlin.AO physics.bio-ph


title:
The Recognizability of Individual Creative Styles Within and Across
  Domains

abstract:
  We present a set of studies that tested the hypothesis that creative style is
recognizable within and across domains. Art students were shown two sets of
paintings, the first by five famous artists and the second by their art student
peers. For both sets, they guessed the creators of the works at above-chance
levels. In a similar study, creative writing students guessed at above-chance
levels which passages were written by which of five famous writers, and which
passages were written by which of their writing student peers. When creative
writing students were asked to produce works of art, they guessed at
above-chance levels which of their peers produced which artwork. Finally, art
students who were familiar with each other's paintings guessed at above-chance
levels which of their peers produced which non-painting artwork. The findings
support the hypothesis that creative styles are recognizable not just within
but also across domains. We suggest this is because all of an individual's
creative outputs are expressions of a particular underlying uniquely structured
self-organizing internal model of the world.


title: Adiabatic projection method for scattering and reactions on the lattice

abstract:
  We demonstrate and test the adiabatic projection method, a general new
framework for calculating scattering and reactions on the lattice. The method
is based upon calculating a low-energy effective theory for clusters which
becomes exact in the limit of large Euclidean projection time. As a detailed
example we calculate the adiabatic two-body Hamiltonian for elastic
fermion-dimer scattering in lattice effective field theory. Our calculation
corresponds to neutron-deuteron scattering in the spin-quartet channel at
leading order in pionless effective field theory. We show that the spectrum of
the adiabatic Hamiltonian reproduces the spectrum of the original Hamiltonian
below the inelastic threshold to arbitrary accuracy. We also show that the
calculated s-wave phase shift reproduces the known exact result in the
continuum and infinite-volume limits. When extended to more than one scattering
channel, the adiabatic projection method can be used to calculate inelastic
reactions on the lattice in future work.


title:
Representation of Dormant and Active Microbial Dynamics for Ecosystem
  Modeling

abstract:
  Dormancy is an essential strategy for microorganisms to cope with
environmental stress. However, global ecosystem models typically ignore
microbial dormancy, resulting in major model uncertainties. To facilitate the
consideration of dormancy in these large-scale models, we propose a new
microbial physiology component that works for a wide range of substrate
availabilities. This new model is based on microbial physiological states and
is majorly parameterized with the maximum specific growth and maintenance rates
of active microbes and the ratio of dormant to active maintenance rates. A
major improvement of our model over extant models is that it can explain the
low active microbial fractions commonly observed in undisturbed soils. Our new
model shows that the exponentially-increasing respiration from
substrate-induced respiration experiments can only be used to determine the
maximum specific growth rate and initial active microbial biomass, while the
respiration data representing both exponentially-increasing and
non-exponentially-increasing phases can robustly determine a range of key
parameters including the initial total live biomass, initial active fraction,
the maximum specific growth and maintenance rates, and the half-saturation
constant. Our new model can be incorporated into existing ecosystem models to
account for dormancy in microbially-mediated processes and to provide improved
estimates of microbial activities.


title:
Dual-target function validation of single-particle selection from
  low-contrast cryo-electron micrographs

abstract:
  Weak-signal detection and single-particle selection from low-contrast
micrographs of frozen hydrated biomolecules by cryo-electron microscopy
(cryo-EM) presents a practical challenge. Cryo-EM image contrast degrades as
the size of biomolecules of structural interest decreases. When the image
contrast falls into a range where the location or presence of single particles
becomes ambiguous, a need arises for objective computational approaches to
detect weak signal and to select and verify particles from these low-contrast
micrographs. Here we propose an objective validation scheme for low-contrast
particle selection using a combination of two different target functions. In an
implementation of this dual-target function (DTF) validation, a first target
function of fast local correlation was used to select particles through
template matching, followed by signal validation through a second target
function of maximum likelihood. By a systematic study of simulated data, we
found that such an implementation of DTF validation is capable of selecting and
verifying particles from cryo-EM micrographs with a signal-to-noise ratio as
low as 0.002. Importantly, we demonstrated that DTF validation can robustly
evade over-fitting or reference bias from the particle-picking template,
allowing true signal to emerge from amidst heavy noise in an objective fashion.
The DTF approach allows efficient assembly of a large number of single-particle
cryo-EM images of smaller biomolecules or specimens containing
contrast-degrading agents like detergents in a semi-automatic manner.


title: Amplification and attenuation of a probe signal by doubly-dressed states

abstract:
  We analyse a system composed of a qubit coupled to electromagnetic fields of
two high quality quantum oscillators. Particular realization of such a system
is the superconducting qubit coupled to a transmission-line resonator driven by
two signals with frequencies close to the resonator's harmonics. One strong
signal is used for exciting the system to a high energetic state while the
second weak signal is applied for probing effective eigenstates of the system.
We demonstrate that a description of the system dynamics as doubly dressed
qubit is applicable. Experiments show that in the case of high quality
resonators the energy levels and the resonance conditions can be probed even
for high driving amplitudes. The interaction of the qubit with photons of two
harmonics has prospects to be used as a quantum amplifier or an attenuator.


title: Time-energy tradeoff in unambiguous state discrimination POVM

abstract:
  Unambiguous non-orthogonal state discrimination has fundamental importance in
quantum information and quantum cryptography. The discrimination is carried out
by POVM generalized measurements. For this process, we find a tradeoff between
the needed energy resources and the evolution time, and express it in terms of
action-like cost inequality. We find the realization that minimizes this
action-like cost and show that in this case the cost is determined by the
maximal population transfer from the system to the ancilla needed for the POVM
implementation.


title: Multiple Collisions in Systems of Competing Brownian Particles

abstract:
  Consider a finite system of competing Brownian particles on the real line.
Each particle moves as a Brownian motion, with drift and diffusion coefficients
depending only on its current rank relative to the other particles. We find a
sufficient condition for a.s. absence of a total collision (when all particles
collide) and of other types of collisions, say of the three lowest-ranked
particles. This continues the work of Ichiba, Karatzas, Shkolnikov (2013) and
Sarantsev (2015).


title: Five clarifications about cultural evolution

abstract:
  This paper reviews and clarifies five misunderstandings about cultural
evolution identified by Henrich, Boyd, and Richerson (2008). First, cultural
representations are neither discrete nor continuous; they are distributed
across neurons that respond to microfeatures. This enables associations to be
made, and cultural change to be generated. Second, 'replicator dynamics' do not
ensure natural selection. The replicator notion does not capture the
distinction between actively interpreted self-assembly code and passively
copied self-description, which leads to a fundamental principle of natural
selection: inherited information is transmitted, whereas acquired information
is not. Third, this principle is violated in culture by the ubiquity of
acquired change. Moreover, biased transmission is less important to culture
than the creative processes by which novelty is generated. Fourth, there is no
objective basis for determining cultural fitness. Fifth, the necessity of
randomness is discussed. It is concluded that natural selection is
inappropriate as an explanatory framework for culture.


title: Improved Determination of the Neutron Lifetime

abstract:
  The most precise determination of the neutron lifetime using the beam method
was completed in 2005 and reported a result of $\tau_n = (886.3 \pm 1.2
[\textrm{stat}] \pm 3.2 [\textrm{syst}])$ s. The dominant uncertainties were
attributed to the absolute determination of the fluence of the neutron beam
(2.7 s). The fluence was measured with a neutron monitor that counted the
neutron-induced charged particles from absorption in a thin, well-characterized
6Li deposit. The detection efficiency of the monitor was calculated from the
areal density of the deposit, the detector solid angle, and the evaluated
nuclear data file, ENDF/B-VI 6Li(n,t)4He thermal neutron cross section. In the
current work, we have measured the detection efficiency of the same monitor
used in the neutron lifetime measurement with a second, totally-absorbing
neutron detector. This direct approach does not rely on the 6Li(n,t)4He cross
section or any other nuclear data. The detection efficiency is consistent with
the value used in 2005 but was measured with a precision of 0.057 %, which
represents a five-fold improvement in the uncertainty. We have verified the
temporal stability of the neutron monitor through ancillary measurements,
allowing us to apply the measured neutron monitor efficiency to the lifetime
result from the 2005 experiment. The updated lifetime is $\tau_n = (887.7 \pm
1.2 [\textrm{stat}] \pm 1.9 [\textrm{syst}])$ s.


title: Equilibrium points of a singular cooperative system with free boundary

abstract:
  In this paper we initiate the study of maps minimising the energy
  $$
  \int_{D} (|\nabla \u|^2+2|\u|)\ dx.
  $$ which, due to Lipschitz character of the integrand, gives rise to the
singular Euler equations
  $$
  \Delta \u=\frac{\u}{|\u|}\chi_{\left\lbrace |\u|>0\right\rbrace}, \qquad \u =
(u_1, \cdots, u_m) \ .
  $$ Our primary goal in this paper is to set up a road map for future
developments of the theory related to such energy minimising maps.
  Our results here concern regularity of the solution as well as that of the
free boundary. They are achieved by using monotonicity formulas and
epiperimetric inequalities, in combination with geometric analysis.


title: Measurement of Electron Trapping in the CESR Storage Ring

abstract:
  The buildup of low-energy electrons has been shown to affect the performance
of a wide variety of particle accelerators. Of particular concern is the
persistence of the cloud between beam bunch passages, which can impose
limitations on the stability of operation at high beam current. We have
obtained measurements of long-lived electron clouds trapped in the field of a
quadrupole magnet in a positron storage ring, with lifetimes much longer than
the revolution period. Based on modeling, we estimate that about 7% of the
electrons in the cloud generated by a 20-bunch train of 5.3 GeV positrons with
16-ns spacing and $1.3x10^{11}$ population survive longer than 2.3 $\mu$s in a
quadrupole field of gradient 7.4 T/m. We have observed a non-monotonic
dependence of the trapping effect on the bunch spacing. The effect of a witness
bunch on the measured signal provides direct evidence for the existence of
trapped electrons. The witness bunch is also observed to clear the cloud,
demonstrating its effectiveness as a mitigation technique.


title: Some new maximum VC classes

abstract:
  Set systems of finite VC dimension are frequently used in applications
relating to machine learning theory and statistics. Two simple types of VC
classes which have been widely studied are the maximum classes (those which are
extremal with respect to Sauer's lemma) and so-called Dudley classes, which
arise as sets of positivity for linearly parameterized functions. These two
types of VC class were related by Floyd, who gave sufficient conditions for
when a Dudley class is maximum. It is widely known that Floyd's condition
applies to positive Euclidean half-spaces and certain other classes, such as
sets of positivity for univariate polynomials.
  In this paper we show that Floyd's lemma applies to a wider class of linearly
parameterized functions than has been formally recognized to date. In
particular we show that, modulo some minor technicalities, the sets of
positivity for any linear combination of real analytic functions is maximum on
points in general position. This includes sets of positivity for multivariate
polynomials as a special case.


title: Weighted quantile regression for longitudinal data

abstract:
  Quantile regression is a powerful statistical methodology that complements
the classical linear regression by examining how covariates influence the
location, scale, and shape of the entire response distribution and offering a
global view of the statistical landscape. In this paper we propose a new
quantile regression model for longitudinal data. The proposed approach
incorporates the correlation structure between repeated measures to enhance the
efficiency of the inference. In order to use the Newton-Raphson iteration
method to obtain convergent estimates, the estimating functions are redefined
as smoothed functions which are differentiable with respect to regression
parameters. Our proposed method for quantile regression provides consistent
estimates with asymptotically normal distributions. Simulation studies are
carried out to evaluate the performance of the proposed method. As an
illustration, the proposed method was applied to a real-life data that contains
self-reported labor pain for women in two groups.


title: Neutrino Quantum Kinetics

abstract:
  We present a formulation of the quantum kinetic equations (QKEs) which govern
the evolution of neutrino flavor at high density and temperature. Here, the
QKEs are derived from the ground up, using fundamental neutrino interactions
and quantum field theory. We show that the resulting QKEs describe coherent
flavor evolution with an effective mass when inelastic scattering is
negligible. The QKEs also contain a collision term. This term can reduce to the
collision term in the Boltzmann equation when scattering is dominant and the
neutrino effective masses and density matrices become diagonal in the
interaction basis. We also find that the QKE's include equations of motion for
a new dynamical quantity related to neutrino spin. This quantity decouples from
the equations of motion for the density matrices at low densities or in
isotropic conditions. However, the spin equations of motion allow for the
possibility of coherent transformation between neutrinos and antineutrinos at
high densities and in the presence of anisotropy. Although the requisite
conditions for this exist in the core collapse supernova and compact object
merger environments, it is likely that only a self consistent incorporation of
the QKEs in a sufficiently realistic model could establish whether or not
significant neutrino-antineutrino conversion occurs.


title: Two estimates of the distance to the Galactic centre

abstract:
  We use recently updated globular cluster distances to estimate the distance
to the Galactic centre, finding 7.4 \pm 0.2|stat \pm 0.2|sys kpc from symmetry
considerations. We recalibrate the red clump magnitude from Hipparcos stars,
finding a skew distribution and a significant difference between peak and mean
magnitudes. We find an estimate from stars in the periphery of the bulge using
2MASS, R0 = 7.5 \pm 0.3 kpc, in agreement with the figure from the halo
centroid. We resolve discrepancies in the literature between estimates from the
red clump. Our results are consistent with those found by different
methodologies after taking systematic errors into account.


title: Classifying Supernovae Using Only Galaxy Data

abstract:
  We present a new method for probabilistically classifying supernovae (SNe)
without using SN spectral or photometric data. Unlike all previous studies to
classify SNe without spectra, this technique does not use any SN photometry.
Instead, the method relies on host-galaxy data. We build upon the well-known
correlations between SN classes and host-galaxy properties, specifically that
core-collapse SNe rarely occur in red, luminous, or early-type galaxies. Using
the nearly spectroscopically complete Lick Observatory Supernova Search sample
of SNe, we determine SN fractions as a function of host-galaxy properties.
Using these data as inputs, we construct a Bayesian method for determining the
probability that a SN is of a particular class. This method improves a common
classification figure of merit by a factor of >2, comparable to the best
light-curve classification techniques. Of the galaxy properties examined,
morphology provides the most discriminating information. We further validate
this method using SN samples from the Sloan Digital Sky Survey and the Palomar
Transient Factory. We demonstrate that this method has wide-ranging
applications, including separating different subclasses of SNe and determining
the probability that a SN is of a particular class before photometry or even
spectra can. Since this method uses completely independent data from
light-curve techniques, there is potential to further improve the overall
purity and completeness of SN samples and to test systematic biases of the
light-curve techniques. Further enhancements to the host-galaxy method,
including additional host-galaxy properties, combination with light-curve
methods, and hybrid methods should further improve the quality of SN samples
from past, current, and future transient surveys.


title:
Exploring the Milky Way stellar disk. A detailed elemental abundance
  study of 714 F and G dwarf stars in the Solar neighbourhood

abstract:
  ABRIDGED: METHODS: We have conducted a high-resolution spectroscopic study of
714 F and G dwarf and subgiant stars in the Solar neighbourhood. The star
sample has been kinematically selected to trace the Galactic thin and thick
disks to their extremes...... The determination of stellar parameters and
elemental abundances is based on a standard 1-D LTE analysis using equivalent
width measurements in high-resolution (R=40000-110000) and high signal-to-noise
(S/N=150-300) spectra obtained with..... RESULTS: .... Our data show that there
is an old and alpha-enhanced disk population, and a younger and less
alpha-enhanced disk population. While they overlap greatly in metallicity
between -0.7<[Fe/H]<+0.1, they show a bimodal distribution in [alpha/Fe]. This
bimodality becomes even clearer if stars where stellar parameters and
abundances show larger uncertainties (Teff<5400 K) are discarded, showing that
it is important to constrain the data set to a narrow range in the stellar
parameters if small differences between stellar populations are to be revealed.
We furthermore find that the alpha-enhanced population has orbital parameters
placing the stellar birthplaces in the inner Galactic disk while the low-alpha
stars mainly come from the outer Galactic disk........... We furthermore have
discovered that a standard 1-D, LTE analysis, utilising ionisation and
excitation balance of Fe I and Fe II lines produces a flat lower main sequence.
As the exact cause for this effect is unclear we chose to apply an empirical
correction. Turn-off, and more evolved, stars, appears to be un-affected.


title:
Revival of The Stalled Core-Collapse Supernova Shock Triggered by
  Precollapse Asphericity in the Progenitor Star

abstract:
  Multi-dimensional simulations of advanced nuclear burning stages of massive
stars suggest that the Si/O layers of presupernova stars harbor large
deviations from the spherical symmetry typically assumed for presupernova
stellar structure. We carry out three-dimensional core-collapse supernova
simulations with and without aspherical velocity perturbations to assess their
potential impact on the supernova hydrodynamics in the stalled shock phase. Our
results show that realistic perturbations can qualitatively alter the
postbounce evolution, triggering an explosion in a model that fails to explode
without them. This finding underlines the need for a multi-dimensional
treatment of the presupernova stage of stellar evolution.


title:
Enhanced anti-ferromagnetic exchange between magnetic impurities in a
  superconducting host

abstract:
  It is generally believed that superconductivity only weakly affects the
indirect exchange between magnetic impurities. If the distance r between
impurities is smaller than than the superconducting coherence length (r < \xi),
this exchange is thought to be dominated by RKKY interactions, identical to the
those in a normal metallic host. This perception is based upon a perturbative
treatment of the exchange interaction. Here, we provide a non-perturbative
analysis and demonstrate that the presence of Yu-Shiba-Rusinov bound states
induces a strong 1/r^2 anti-ferromagnetic interaction that can dominate over
conventional RKKY even at distances significantly smaller than the coherence
length. Experimental signatures, implications and applications are discussed.


title:
The effect of bars on the M-sigma relation: offset, scatter and
  residuals correlations

abstract:
  We analyse a set of collisionless disc galaxy simulations to study the
consequences of bar formation and evolution on the M-sigma relation of
supermassive black holes. The redistribution of angular momentum driven by bars
leads to a mass increase within the central region, raising the velocity
dispersion of the bulge, sigma, on average by ~12% and as much as ~20%. If a
disc galaxy with a SMBH satisfying the M-sigma relation forms a bar, and the
SMBH does not grow in the process, then the increase in sigma moves the galaxy
off the M-sigma relation. We explore various effects that can affect this
result including contamination from the disc and anisotropy. The displacement
from the M-sigma relation for individual model barred galaxies correlates with
both M(B)/M(B+D) and beta_phi(B+D) measured within the effective radius of the
bulge. Overall, this process leads to an M-sigma for barred galaxies offset
from that of unbarred galaxies, as well as an increase in its scatter. We
assemble samples of unbarred and barred galaxies with classical bulges and find
tentative hints of an offset between the two consistent with the predicted.
Including all barred galaxies, rather than just those with a classical bulge,
leads to a significantly larger offset.


title: Viscous Kelvin-Helmholtz instabilities in highly ionised plasmas

abstract:
  Transport coefficients in highly ionised plasmas like the intra-cluster
medium (ICM) are still ill-constrained. They influence various processes, among
them the mixing at shear flow interfaces due to the Kelvin-Helmholtz
instability (KHI). The observed structure of potential mixing layers can be
used to infer the transport coefficients, but the data interpretation requires
a detailed knowledge of the long-term evolution of the KHI under different
conditions. Here we present the first systematic numerical study of the effect
of constant and temperature-dependent isotropic viscosity over the full range
of possible values. We show that moderate viscosities slow down the growth of
the KHI and reduce the height of the KHI rolls and their rolling-up.
Viscosities above a critical value suppress the KHI. The effect can be
quantified in terms of the Reynolds number Re = U{\lambda}/{\nu}, where U is
the shear velocity, {\lambda} the perturbation length, and {\nu} the kinematic
viscosity. We derive the critical Re for constant and temperature dependent,
Spitzer-like viscosities, an empirical relation for the viscous KHI growth time
as a function of Re and density contrast, and describe special behaviours for
Spitzer-like viscosities and high density contrasts. Finally, we briefly
discuss several astrophysical situations where the viscous KHI could play a
role, i.e., sloshing cold fronts, gas stripping from galaxies, buoyant
cavities, ICM turbulence, and high velocity clouds.


title: Rotational spectroscopy of interstellar PAHs

abstract:
  Polycyclic aromatic hydrocarbons (PAHs) are believed to be ubiquitous in the
interstellar medium. Yet, to date no specific PAH molecule has been identified.
In this paper, a new observational avenue is suggested to detect individual
PAHs, using their rotational line emission at radio frequencies. Previous PAH
searches based on rotational spectroscopy have only targeted the bowl-shaped
corannulene molecule, with the underlying assumption that other polar PAHs are
triaxial and have a complex and diluted spectrum unusable for identification
purposes. In this paper the rotational spectrum of quasi-symmetric PAHs is
computed analytically. It is shown that the asymmetry of planar,
nitrogen-substituted symmetric PAHs is small enough that their rotational
spectrum, when observed with a resolution of about a MHz, has the appearance of
a "comb" of evenly spaced stacks of lines. The simple pattern of these "comb"
spectra allows for the use of matched-filtering techniques, which can result in
a significantly enhanced signal-to-noise ratio. Detection forecasts are
discussed for regions harbouring "anomalous microwave emission", believed to
originate from the collective PAH rotational emission. A systematic search for
PAH lines in various environments is advocated. If detected, PAH "combs" would
allow to the conclusive and unambiguous identification of specific,
free-floating interstellar PAHs.