title: Maximizing Barrier Coverage Lifetime with Mobile Sensors

abstract:
  Sensor networks are ubiquitously used for detection and tracking and as a
result covering is one of the main tasks of such networks. We study the problem
of maximizing the coverage lifetime of a barrier by mobile sensors with limited
battery powers, where the coverage lifetime is the time until there is a
breakdown in coverage due to the death of a sensor. Sensors are first deployed
and then coverage commences. Energy is consumed in proportion to the distance
traveled for mobility, while for coverage, energy is consumed in direct
proportion to the radius of the sensor raised to a constant exponent. We study
two variants which are distinguished by whether the sensing radii are given as
part of the input or can be optimized, the fixed radii problem and the variable
radii problem. We design parametric search algorithms for both problems for the
case where the final order of the sensors is predetermined and for the case
where sensors are initially located at barrier endpoints. In contrast, we show
that the variable radii problem is strongly NP-hard and provide hardness of
approximation results for fixed radii for the case where all the sensors are
initially co-located at an internal point of the barrier.


title:
Combined first-principles and EXAFS study of structural instability in
  BaZrO3

abstract:
  Phonon spectrum of cubic barium zirconate is calculated from first principles
using the density functional theory. Unstable phonon mode with the $R_{25}$
symmetry in the phonon spectrum indicates an instability of the cubic structure
with respect to rotations of the oxygen octahedra. It is shown that the
ground-state structure of the crystal is $I4/mcm$. In order to find the
manifestations of the predicted instability, EXAFS measurements at the Ba
$L_{\rm III}$-edge are used to study the local structure of BaZrO$_3$ at 300 K.
An enhanced value of the Debye-Waller factor for the Ba-O atomic pair
($\sigma^2_1 \sim 0.015$ {\AA}$^2$) revealed in the experiment is associated
with the predicted structural instability. The average amplitude of the thermal
octahedra rotation estimated from the measured $\sigma^2_1$ value is $\sim$4
degrees at 300 K. The closeness of the calculated energies of different
distorted phases resulting from the condensation of the $R_{25}$ mode suggests
a possible structural glass formation in BaZrO$_3$ when lowering temperature,
which explains the cause of the discrepancy between the calculations and
experiment.


title: Assessment of Path Reservation in Distributed Real-Time Vehicle Guidance

abstract:
  In this paper we assess the impact of path reservation as an additional
feature in our distributed real-time vehicle guidance protocol BeeJamA. Through
our microscopic simulations we show that na\"{\i}ve reservation of links
without any further measurements is only an improvement in case of complete
market penetration, otherwise it even reduces the performance of our approach
based on real-time link loads. Moreover, we modified the reservation process to
incorporate current travel times and show that this improves the results in our
simulations when at least 40% market penetration is possible.


title:
Analysis and interpretation of the Cramer-Rao lower-bound in astrometry:
  One dimensional case

abstract:
  In this paper we explore the maximum precision attainable in the location of
a point source imaged by a pixel array detector in the presence of a
background, as a function of the detector properties. For this we use a
well-known result from parametric estimation theory, the so-called Cramer-Rao
lower bound. We develop the expressions in the 1-dimensional case of a linear
array detector in which the only unknown parameter is the source position. If
the object is oversampled by the detector, analytical expressions can be
obtained for the Cramer-Rao limit that can be readily used to estimate the
limiting precision of an imaging system, and which are very useful for
experimental (detector) design, observational planning, or performance
estimation of data analysis software: In particular, we demonstrate that for
background-dominated sources, the maximum astrometric precision goes as
$B/F^2$, where $B$ is the background in one pixel, and $F$ is the total flux of
the source, while when the background is negligible, this precision goes as
$F^{-1}$. We also explore the dependency of the astrometric precision on: (1)
the size of the source (as imaged by the detector), (2) the pixel detector
size, and (3) the effect of source de-centering. Putting these results into
context, the theoretical Cramer-Rao lower bound is compared to both ground- as
well as spaced-based astrometric results, indicating that current techniques
approach this limit very closely. Our results indicate that we have found in
the Cramer-Rao lower variance bound a very powerful astrometric "benchmark"
estimator concerning the maximum expected positional precision for a point
source, given a prescription for the source, the background, the detector
characteristics, and the detection process.


title:
Phenomenological constraints on universal extra dimensions at LHC and
  electroweak precision test

abstract:
  We show two types of bounds on five- and six-demensional universal extra
dimension (UED) models from the latest results of the Higgs search at the LHC
and of the electroweak precision data for the S and T parameters. The UED
models on which we put lower bounds are the minimal UED model in five
dimensions and the six dimensional ones. The highest possible ultraviolet
cutoff scale for each UED model is evaluated from the vacuum stability of the
Higgs potential by solving the renormalization group equation of the Higgs self
coupling. The bounds on the KK scale in the minimal UED model is 650 GeV from
the LHC results and 700 GeV from the S, T analysis at the 95% confidence level,
while those in the several 6D UED models are from 850 GeV to 1350 GeV (Higgs
search) and from 900 GeV to 1500 GeV (S,T analysis).


title: Incomputability after Alan Turing

abstract:
  Incomputability as a mathematical notion arose from work of Alan Turing and
Alonzo Church in the 1930s. Like Turing himself, it attracted less attention
than it deserved beyond the confines of mathematics. Today our experiences in
computer science, physics, biology, artificial intelligence, economics and the
humanities point to the importance of the notion for understanding the world
around us. This article takes a Turing centenary look at how the interface
between the computable world and the incomputable formed a central theme in
Turing's work - from the early establishment of the standard model of the
stored program computer, to the late work on emergence of form in nature, and
the first approaches to understanding and simulating human intelligence.
Turing's thinking was remarkably prescient, and his legacy still impacts on
much of our work. The incomputable may turn out to be a specially important
part of the legacy, with consequences that Alan Turing himself could not have
envisaged.


title: Identification of 5 Interacting Binaries in the Galactic Bulge Survey

abstract:
  We present optical lightcurves, spectroscopy, and classification of five
X-ray sources in the Chandra Galactic Bulge Survey [CXOGBS J174009.1-284725
(CX5), CXOGBS J173935.7-272935 (CX18), CXOGBS J173946.9-271809 (CX28), CXOGBS
J173729.1-292804 (CX37), CXOGBS J174607.6-261547 (CX561)]. These objects were
selected based on bright optical counterparts which were quickly found to have
emission lines in their optical spectra. This paper presents an illustration of
GBS optical follow-up, targeting emission line objects. Of these five objects,
four exhibit photometric variability in the Sloan r' band. CX5 shows a
tentative period of 2.1 hours and is clearly an Intermediate Polar (IP). CX28
and CX37 both exhibit flickering with no clear period. Both are suggested to
also be IPs. CX18 was observed to undergo 2 dwarf nova outbursts. Finally,
CX561 shows no detectable variability, although its characteristics would be
consistent with either a quiescent Low Mass X-ray Binary or Cataclysmic
Variable.


title: Search for D+(s) to pi+ mu+ mu- and D+(s) to pi- mu+ mu+ decays

abstract:
  A search for non-resonant D+(s) to pi+mu+mu- and D+(s) to pi-mu+mu+ decays is
performed using proton-proton collision data, corresponding to an integrated
luminosity of 1.0 fb-1, at sqrt(s) = 7 TeV recorded by the LHCb experiment in
2011. No signals are observed and the 90% (95%) confidence level (CL) limits on
the branching fractions are
  B(D+ to pi+mu+mu-) < 7.3 (8.3) x 10-8,
  B(Ds+ to pi+mu+mu-) < 4.1 (4.8) x 10-7,
  B(D+ to pi-mu+mu+) < 2.2 (2.5) x 10-8,
  B(Ds+ to pi-mu+mu+) < 1.2 (1.4) x 10-7.
  These limits are the most stringent to date.


title: Making sessile drops easier

abstract:
  Using an identity, directly derived from the Young-Laplace equation, the
problem of the equilibrium shape of an axisymmetric sessile drop is reduced to
a one-parameter shooting method problem. Based on the method the numerical
solutions for drops with Bond number up to 15 are plotted. The agreement
between the method and the ADSA-D method as well as the experimental data is
tested. A Mathematica code based on the method is presented.


title:
CF2 White Paper: Status and Prospects of The VERITAS Indirect Dark
  Matter Detection Program

abstract:
  In this white paper, submitted as a part of Snowmass 2013 (subgroup CF2), we
examine the current status and future prospects of the VERITAS indirect dark
matter detection program. The VERITAS array of imaging atmospheric Cherenkov
telescopes (IACTs), sensitive in the 0.1-50 TeV regime, is in the process of
completing a multi-year program aimed at detecting signatures of neutralino
dark matter. This program is spread out over a range of astrophysical targets
which can potentially yield definitive signatures of neutralino
self-annihilation such as dwarf spheroidal galaxies (dSphs) and the center of
the Milky Way galaxy. While the program is still in progress, initial results
on dSphs have produced very competitive upper limits on the thermally averaged
cross-section of neutralino self-annihilation as well as strongly constraining
leptophillic dark matter models (such as those inferred from the PAMELA and AMS
positron fraction results). As the program continues over the next 5 years,
VERITAS observations will yield some of the strongest constraints available
from IACTs, pushing down the limit on the thermally averaged cross-section of
neutralino self-annihilation to the expected natural thermal relic scale.


title:
The Determinant Line Bundle for Fredholm Operators: Construction,
  Properties, and Classification

abstract:
  We provide a thorough construction of a system of compatible determinant line
bundles over spaces of Fredholm operators, fully verify that this system
satisfies a number of important properties, and include explicit formulas for
all relevant isomorphisms between these line bundles. We also completely
describe all possible systems of compatible determinant line bundles and
compare the conventions and approaches used elsewhere in the literature.


title: Non-integrability of the dumbbell and point mass problem

abstract:
  This paper discusses a constrained gravitational three-body problem with two
of the point masses separated by a massless inflexible rod to form a dumbbell.
The non-integrability of this system is proven using differential Galois
theory.


title:
Existence and non-existence of breather solutions in damped and driven
  nonlinear lattices

abstract:
  We investigate the existence of spatially localised solutions, in the form of
discrete breathers, in general damped and driven nonlinear lattice systems of
coupled oscillators. Conditions for the exponential decay of the difference
between the maximal and minimal amplitudes of the oscillators are provided
which proves that initial non-uniform spatial patterns representing breathers
attain exponentially fast a spatially uniform state preventing the formation
and/or preservation of any breather solution at all. Strikingly our results are
generic in the sense that they hold for arbitrary dimension of the system, any
attractive interaction, coupling strength and on-site potential and general
driving fields. Furthermore, our rigorous quantitative results establish
conditions under which discrete breathers in general damped and driven
nonlinear lattices can exist at all and open the way for further research on
the emergent dynamical scenarios, in particular features of pattern formation,
localisation and synchronisation, in coupled cell networks.


title: On Fuzzy semihyperrings

abstract:
  In this article we introduce the study of fuzzy semihyperrings and fuzzy
R-semihypermodules, where R is a semihyperrings and R-semihypermodules are
represntations of R. In particular, semihyperrings all of whose hyperideals are
idempotent, called fully idempotent semihyperrings, are investigated in a fuzzy
context. It is proved, among other results, that a semihyperring R is fully
idempotent if and only if the lattics of fuzzy hyperideals of R is distributive
under the sum and product of fuzzy hyperideals. It is also shown that the set
of proper fuzzy prime hyperideals of a fully idempotent semihyperring R admits
the structure of a topological space, called the fuzzy prime spectrum of R.


title:
Combining collective, MSW, and turbulence effects in supernova neutrino
  flavor evolution

abstract:
  (Abridged) In order to decode the neutrino burst signal from a Galactic
core-collapse supernova and reveal the complicated inner workings of the
explosion we need a thorough understanding of the neutrino flavor evolution
from the proto-neutron star outwards. The flavor content of the signal evolves
due to both neutrino collective effects and matter effects which can lead to a
highly interesting interplay and distinctive spectral features. In this paper
we investigate the supernova neutrino flavor evolution in three different
progenitors and include collective flavor effects, the evolution of the
Mikheyev, Smirnov & Wolfenstein conversion due to the shock wave passage
through the star, and the impact of turbulence. In the Oxygen-Neon-Magnesium
supernova we find that the impact of turbulence is both brief and slight during
a window of 1-2 seconds post bounce. Thus the spectral features of collective
and shock effects in the neutrino signals from ONeMg supernovae may be almost
turbulence free making them the easiest to interpret. For the more massive
progenitors we again find that small amplitude turbulence, up to 10%, leads to
a minimal modification of the signal, and the emerging neutrino spectra retain
both collective and MSW features. However, when larger amounts of turbulence is
added, 30% and 50%, the features of collective and shock wave effects in the
high density resonance channel are almost completely obscured at late times.
Yet at the same time we find the other mixing channels - the low density
resonance channel and the non-resonant channels - begin to develop turbulence
signatures. Large amplitude turbulent motions in the outer layers of more
massive, iron core-collapse supernovae may obscure the most obvious
fingerprints of collective and shock wave effects in the neutrino signal but
cannot remove them completely, and additionally bring about new features in the
signal.


title: Homotopy BV algebras in Poisson geometry

abstract:
  We define and study the degeneration property for BV-infinity algebras and
show that it implies that the underlying L-infinity algebras are homotopy
abelian. The proof is based on a generalisation of the well-known identity
\Delta(e^x)=e^x(\Delta(x)+[x,x]/2) which holds in all BV algebras. As an
application we show that the higher Koszul brackets on the cohomology of a
manifold supplied with a generalised Poisson structure all vanish.


title:
Preparation of entangled and antiferromagnetic states by dissipative
  Rydberg pumping

abstract:
  We propose and analyze an approach for preparation of high fidelity
entanglement and antiferromagnetic states using Rydberg mediated interactions
with dissipation. Using asymmetric Rydberg interactions the two-atom Bell
singlet is a dark state of the Rydberg pumping process. Master equation
simulations demonstrate Bell singlet preparation fidelity $\mcF=0.998$.
Antiferromagnetic states are generated on a four spin plaquette in agreement
with results found from diagonalization of the transverse field Ising
Hamiltonian.


title: Evolution in a Changing Environment

abstract:
  We propose a simple model for genetic adaptation to a changing environment,
describing a fitness landscape characterized by two maxima. One is associated
with "specialist" individuals that are adapted to the environment; this maximum
moves over time as the environment changes. The other maximum is static, and
represents "generalist" individuals not affected by environmental changes. The
rest of the landscape is occupied by "maladapted" individuals. Our analysis
considers the evolution of these three subpopulations. Our main result is that,
in presence of a sufficiently stable environmental feature, as in the case of
an unchanging aspect of a physical habitat, specialists can dominate the
population. By contrast, rapidly changing environmental features, such as
language or cultural habits, are a moving target for the genes; here,
generalists dominate, because the best evolutionary strategy is to adopt
neutral alleles not specialized for any specific environment. The model we
propose is based on simple assumptions about evolutionary dynamics and
describes all possible scenarios in a non-trivial phase diagram. The approach
provides a general framework to address such fundamental issues as the Baldwin
effect, the biological basis for language, or the ecological consequences of a
rapid climate change.


title:
Sharp bounds for higher linear syzygies and classifications of
  projective varieties

abstract:
  In the present paper, we consider upper bounds of higher linear syzygies i.e.
graded Betti numbers in the first linear strand of the minimal free resolutions
of projective varieties in arbitrary characteristic. For this purpose, we first
remind `Partial Elimination Ideals (PEIs)' theory and introduce a new framework
in which one can study the syzygies of embedded projective schemes well using
PEIs theory and the reduction method via inner projections.
  Next we establish fundamental inequalities which govern the relations between
the graded Betti numbers in the first linear strand of an algebraic set $X$ and
those of its inner projection $X_q$. Using these results, we obtain some
natural sharp upper bounds for higher linear syzygies of any nondegenerate
projective variety in terms of the codimension with respect to its own
embedding and classify what the extremal case and next-to-extremal case are.
This is a generalization of Castelnuovo and Fano's results on the number of
quadrics containing a given variety and another characterization of varieties
of minimal degree and del Pezzo varieties from the viewpoint of `syzygies'.
Note that our method could be also applied to get similar results for more
general categories (e.g. connected in codimension one algebraic sets).


title:
X-ray Scaling Relation in Early-Type Galaxies: Dark Matter as a Primary
  Factor in Retaining Hot Gas

abstract:
  We have revisited the X-ray scaling relations of early type galaxies (ETG) by
investigating, for the first time, the LX,Gas - MTotal relation in a sample of
14 ETGs. In contrast to the large scatter (by a factor of 102-103) in the
LX,Total - LB relation, we found a tight correlation between these physically
motivated quantities with a rms deviation of a factor of 3 in LX,Gas = 1038 -
1043 erg s-1 or MTotal = a few x 1010 - a few x 1012 Mo. More striking, this
relation becomes even tighter with a rms deviation of a factor of 1.3 among the
gas-rich galaxies (with LX,Gas > 1040 erg s-1). In a simple power-law form, the
new relation is (LX,Gas / 1040 erg s-1) = (MTotal / 3.2 x 1011 Mo)3. This
relation is also consistent with the steep relation between the gas luminosity
and temperature, LX,Gas ~ TGas4.5, identified by Boroson, Kim & Fabbiano
(2011), if the gas is virialized. Our results indicate that the total mass of
an ETG is the primary factor in regulating the amount of hot gas. Among the
gas-poor galaxies (with LX,Gas < a few x 1039 erg s-1), the scatter in the
LX,Gas - MTotal (and LX,Gas - TGas) relation increases, suggesting that
secondary factors (e.g., rotation, flattening, star formation history, cold gas
etc.) may become important.


title:
Alteration of gas phase ion polarizabilities upon hydration in high
  dielectric liquids

abstract:
  We investigate the modification of gas phase ion polarizabilities upon
solvation in polar solvents and ionic liquids. To this aim, we develop a
classical electrostatic theory of charged liquids composed of solvent molecules
modeled as finite size dipoles, and embedding polarizable ions that consist of
Drude oscillators. In qualitative agreement with ab-initio calculations of
polar solvents and ionic liquids, the hydration energy of a polarizable ion in
both type of dielectric liquid is shown to favor the expansion of its
electronic cloud. Namely, the ion carrying no dipole moment in the gas phase
acquires a dipole moment in the liquid environment, but its electron cloud also
reaches an enhanced rigidity. We find that the overall effect is an increase of
the gas phase polarizability upon hydration. In the specific case of ionic
liquids, it is shown that this hydration process is driven by a collective
solvation mechanism where the dipole moment of a polarizable ion induced by its
interaction with surrounding ions self-consistently adds to the polarization of
the liquid, thereby amplifying the dielectric permittivity of the medium in a
substantial way. We propose this self-consistent hydration as the underlying
mechanism behind the high dielectric permittivities of ionic liquids composed
of small charges with negligible gas phase dipole moment. Hydration being a
correlation effect, the emerging picture indicates that electrostatic
correlations cannot be neglected in polarizable liquids.


title:
Semi-Optimal Edge Detector based on Simple Standard Deviation with
  Adjusted Thresholding

abstract:
  This paper proposes a novel method which combines both median filter and
simple standard deviation to accomplish an excellent edge detector for image
processing. First of all, a denoising process must be applied on the grey scale
image using median filter to identify pixels which are likely to be
contaminated by noise. The benefit of this step is to smooth the image and get
rid of the noisy pixels. After that, the simple statistical standard deviation
could be computed for each 2X2 window size. If the value of the standard
deviation inside the 2X2 window size is greater than a predefined threshold,
then the upper left pixel in the 2?2 window represents an edge. The visual
differences between the proposed edge detector and the standard known edge
detectors have been shown to support the contribution in this paper.


title:
Characteristics of Power Loss in SMC a Key for Desining the Best Values
  of Technological Parameters

abstract:
  Optimization of power loss in soft magnetic components basis on the choice of
the best technological parameters values. Therefore, the power losses have been
measured in Somaloy 500 samples for a wide range of frequency and magnetic
induction. These samples have been prepared under a wide range of the hardening
temperatures and pressures. The power loss characteristics have been derived by
assuming that investigated samples obeyed the scaling law. Agreement obtained
between experimental data and the scaling theory has confirmed this assumption.
Moreover, the experimental data of the given sample have been collapsed to a
single curve which represented measurements for all values of frequency an
magnetic induction pick. Therefore, the scaling transforms the losses
characteristics from the two dimensional surfaces to the one dimensional
curves. The samples were produced according two methods: for different
pressures with constant temperature and at different temperatures with constant
pressure. In both cases the power losses decrease with increasing pressure and
with increasing temperature. These trends in decreasing losses stopped for
certain critical values of pressure and temperature, respectively. Above these
values the power losses increase suddenly. Therefore, the mentioned above the
critical pressure and the critical temperature are sought after solutions for
optimal values. In order to reduce the parameters values set the limit curve in
the pressure-temperature plane has been derive. This curve constitutes a
separation curve between the parameters values corresponding to high and low
losses.


title: Quantum Supersymmetric Cosmology and its Hidden Kac-Moody Structure

abstract:
  We study the quantum dynamics of a supersymmetric squashed three-sphere by
dimensionally reducing (to one timelike dimension) the action of D=4 simple
supergravity for an SO(3)-homogeneous (Bianchi IX) cosmological model. The
quantization of the homogeneous gravitino field leads to a 64-dimensional
fermionic Hilbert space. The algebra of the supersymmetry constraints and of
the Hamiltonian one is found to close. One finds that the quantum Hamiltonian
is built from operators that generate a 64-dimensional representation of the
(infinite-dimensional) maximally compact sub-algebra of the rank-3 hyperbolic
Kac-Moody algebra AE_3. Some exponentials of these operators generate a
spinorial extension of the Weyl group of AE_3 which describe (in the small
wavelength limit) the chaotic quantum evolution of the universe near the
cosmological singularity.


title: On quantization of quasi-Lie bialgebras

abstract:
  We modify the quantization of Etingof and Kazhdan so that it can be used to
quantize quasi-Lie bialgebras.


title:
The Stochastic Gradient Descent for the Primal L1-SVM Optimization
  Revisited

abstract:
  We reconsider the stochastic (sub)gradient approach to the unconstrained
primal L1-SVM optimization. We observe that if the learning rate is inversely
proportional to the number of steps, i.e., the number of times any training
pattern is presented to the algorithm, the update rule may be transformed into
the one of the classical perceptron with margin in which the margin threshold
increases linearly with the number of steps. Moreover, if we cycle repeatedly
through the possibly randomly permuted training set the dual variables defined
naturally via the expansion of the weight vector as a linear combination of the
patterns on which margin errors were made are shown to obey at the end of each
complete cycle automatically the box constraints arising in dual optimization.
This renders the dual Lagrangian a running lower bound on the primal objective
tending to it at the optimum and makes available an upper bound on the relative
accuracy achieved which provides a meaningful stopping criterion. In addition,
we propose a mechanism of presenting the same pattern repeatedly to the
algorithm which maintains the above properties. Finally, we give experimental
evidence that algorithms constructed along these lines exhibit a considerably
improved performance.


title:
Breakdown of Fermi liquid behavior near the hot spots in a
  two-dimensional model: A two-loop renormalization group analysis

abstract:
  Motivated by a recent experimental observation of a nodal liquid on both
single crystals and thin films of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ by
Chatterjee \emph{et al.} [Nature Physics \textbf{6}, 99 (2010)], we perform a
field-theoretical renormalization group (RG) analysis of a two-dimensional
model consisting of eight points located near the "hot spots" on the Fermi
surface which are directly connected by spin density wave ordering wave vector.
We derive RG equations up to two-loop order describing the flow of renormalized
couplings, quasiparticle weight, several order-parameter response functions,
and uniform spin and charge susceptibilities of the model. We find that while
the order-parameter susceptibilities investigated here become non-divergent at
two loops, the quasiparticle weight vanishes in the low-energy limit,
indicating a breakdown of Fermi liquid behavior at this RG level. Moreover,
both uniform spin and charge susceptibilities become suppressed in the scaling
limit which indicate gap openings in both spin and charge excitation spectra of
the model.


title:
Deviation of Large Scale Gravitoelectromagnetic Field in Post-Newtonian
  Approximation

abstract:
  In this work a study of the gravity is made using Einstein's equation in the
post-Newtonian approach. This is a method to linearise the General Relativity
indicated to treat non-relativistic objects. It enables us to construct, from
metric-independent elements, fields that are governed by equations similar to
the Maxwell's ones in Lorentz gauge. We promediate these equations for matter
distributed in local systems, like solar systems or galaxies. Finally we define
the large scale fields for this distribution, which includes terms analogous to
electromagnetic case, like polarization, magnetization and superiors terms.


title:
A study of heavy flavor quarks produced in association with top quark
  pairs at sqrt(s) = 7 TeV using the ATLAS detector

abstract:
  Using a sample of dilepton top-quark pair (ttbar) candidate events, a study
is performed of the production of top-quark pairs together with heavy-flavor
(HF) quarks, ttbar+b+X or ttbar+c+X, collectively referred to as ttbar+HF. The
dataset used corresponds to an integrated luminosity of 4.7 fb-1 of
proton--proton collisions at a center-of-mass energy of 7 TeV recorded by the
ATLAS detector at the CERN Large Hadron Collider. The presence of additional HF
quarks in the ttbar sample is inferred by looking for events with at least
three b-tagged jets, where two are attributed to the b-quarks from the ttbar
decays and the third to additional HF production. The dominant background to
ttbar+HF in this sample is ttbar+jet events in which a light-flavor jet is
misidentified as a heavy-flavor jet. To determine the heavy- and light-flavor
content of the additional b-tagged jets, a fit to the vertex mass distribution
of b-tagged jets in the sample is performed. The result of the fit shows that
79 +/- 14 (stat.) +/- 22 (syst.) of the 105 selected extra b-tagged jets
originate from HF quarks, three standard deviations away from the hypothesis of
zero ttbar+HF production. The result for extra HF production is quoted as a
ratio (R_HF) of the cross section for ttbar+HF production to the cross section
for ttbar production with at least one additional jet. Both cross sections are
measured in a fiducial kinematic region within the ATLAS acceptance. R_HF is
measured to be [6.2 +/- 1.1 (stat.) +/- 1.8 (syst.)]% for jets with pT>25 GeV
and |eta|<2.5, in agreement with the expectations from Monte Carlo generators.


title:
Quantum critical point lying beneath the superconducting dome in
  iron-pnictides

abstract:
  Whether a quantum critical point (QCP) lies beneath the superconducting dome
has been a long-standing issue that remains unresolved in many classes of
unconventional superconductors, notably cuprates, heavy fermion compounds and
most recently iron-pnictides. The existence of a QCP may offer a route to
understand: the origin of their anomalous non-Fermi liquid properties, the
microscopic coexistence between unconventional superconductivity and magnetic
or some exotic order, and ultimately the mechanism of superconductivity itself.
The isovalent substituted iron-pnictide BaFe$_2$(As$_{1-x}$P$_x$)$_2$ offers a
new platform for the study of quantum criticality, providing a unique
opportunity to study the evolution of the electronic properties in a wide range
of the phase diagram. Recent experiments in BaFe$_2$(As$_{1-x}$P$_x$)$_2$ have
provided the first clear and unambiguous evidence of a second order quantum
phase transition lying beneath the superconducting dome.


title: Operational characterization of scattered MCFLs -- Technical Report

abstract:
  We give a Kleene-type operational characterization of Muller context-free
languages (MCFLs) of well-ordered and scattered words.


title: Casimir interaction and gauge invariance in finite width mirrors

abstract:
  We study the general form of the Casimir interaction between two flat
finite-width, parallel, infinite mirrors, described by their respective vacuum
polarization tensors, under the assumption of translation invariance along the
directions parallel to the planes of the mirrors. Their properties along the
normal coordinates are left, on the other hand, rather arbitrary, but
constrained by the Ward identity for the vacuum polarization tensors. We
construct solutions to those identities, evaluating the corresponding Casimir
energy of the system by reducing the problem to a collection of one-dimensional
systems.


title: The Fundamental Vibration of Molecular Hydrogen

abstract:
  The fundamental ground tone vibration of H2, HD, and D2 is determined to an
accuracy of 2 x 10^-4 cm^-1 from Doppler-free laser spectroscopy in the
collisionless environment of a molecular beam. This rotationless vibrational
splitting is derived from the combination difference between electronic
excitation from the X^1Sg+, v=0 and v=1 levels to a common EF^1g+, v=0 level.
Agreement within $1\sigma$ between the experimental result and a full ab initio
calculation provides a stringent test of quantum electrodynamics in a
chemically-bound system.


title: Gradient Ricci solitons on surfaces

abstract:
  We classify and expose all the gradient Ricci solitons on complete surfaces,
open or closed, with curvature bounded below, and possibly with a discrete set
of cone-like singular points that arise naturally. We give a precise
qualitative description of each metric in terms of a phase portrait, that is
the most accurate description for all cases that do not admit an explicit
expression in terms of elementary functions. Our classification contains
examples of smooth and conic solitons that were not described in the classic
literature. We add some visual embeddings in R^3 for aesthetics.


title: Shock Waves in Weakly Compressed Granular Media

abstract:
  We experimentally probe nonlinear wave propagation in weakly compressed
granular media, and observe a crossover from quasi-linear sound waves at low
impact, to shock waves at high impact. We show that this crossover grows with
the confining pressure $P_0$, whereas the shock wave speed is independent of
$P_0$ --- two hallmarks of granular shocks predicted recently. The shocks
exhibit powerlaw attenuation, which we model with a logarithmic law implying
that local dissipation is weak. We show that elastic and potential energy
balance in the leading part of the shocks.


title: Efficient Algorithms for Approximate Triangle Counting

abstract:
  Counting the number of triangles in a graph has many important applications
in network analysis. Several frequently computed metrics like the clustering
coefficient and the transitivity ratio need to count the number of triangles in
the network. Furthermore, triangles are one of the most important graph classes
considered in network mining. In this paper, we present a new randomized
algorithm for approximate triangle counting. The algorithm can be adopted with
different sampling methods and give effective triangle counting methods. In
particular, we present two sampling methods, called the \textit{$q$-optimal
sampling} and the \textit{edge sampling}, which respectively give $O(sm)$ and
$O(sn)$ time algorithms with nice error bounds ($m$ and $n$ are respectively
the number of edges and vertices in the graph and $s$ is the number of
samples). Among others, we show, for example, that if an upper bound
$\widetilde{\Delta^e}$ is known for the number of triangles incident to every
edge, the proposed method provides an $1\pm \epsilon$ approximation which runs
in $O( \frac{\widetilde{\Delta^e} n \log n}{\widehat{\Delta^e} \epsilon^2} )$
time, where $\widehat{\Delta^e}$ is the average number of triangles incident to
an edge. Finally we show that the algorithm can be adopted with streams. Then
it, for example, will perform 2 passes over the data (if the size of the graph
is known, otherwise it needs 3 passes) and will use $O(sn)$ space.


title:
An infectious disease model on empirical networks of human contact:
  bridging the gap between dynamic network data and contact matrices

abstract:
  The integration of empirical data in computational frameworks to model the
spread of infectious diseases poses challenges that are becoming pressing with
the increasing availability of high-resolution information on human mobility
and contacts. This deluge of data has the potential to revolutionize the
computational efforts aimed at simulating scenarios and designing containment
strategies. However, the integration of detailed data sources yields models
that are less transparent and general. Hence, given a specific disease model,
it is crucial to assess which representations of the raw data strike the best
balance between simplicity and detail. We consider high-resolution data on the
face-to-face interactions of individuals in a hospital ward, obtained by using
wearable proximity sensors. We simulate the spread of a disease in this
community by using an SEIR model on top of different mathematical
representations of the contact patterns. We show that a contact matrix that
only contains average contact durations fails to reproduce the size of the
epidemic obtained with the high-resolution contact data and also to identify
the most at-risk classes. We introduce a contact matrix of probability
distributions that takes into account the heterogeneity of contact durations
between (and within) classes of individuals, and we show that this
representation yields a good approximation of the epidemic spreading properties
obtained by using the high-resolution data. Our results mark a step towards the
definition of synopses of high-resolution dynamic contact networks, providing a
compact representation of contact patterns that can correctly inform
computational models designed to discover risk groups and evaluate containment
policies. We show that this novel kind of representation can preserve in
simulation quantitative features of the epidemics that are crucial for their
study and management.


title: Modeling halo mass functions in chameleon f(R) gravity

abstract:
  On cosmological scales, observations of the cluster abundance currently place
the strongest constraints on f(R) gravity. These constraints lie in the
large-field limit, where the modifications of general relativity can correctly
be modeled by setting the Compton wavelength of the scalar field to its
background value. These bounds are, however, at the verge of penetrating into a
regime, where the modifications become nonlinearly suppressed due to the
chameleon mechanism and cannot be described by this linearized approximation.
For future constraints based on observations subjected to cluster abundance, it
is therefore essential to consistently model the chameleon effect. We analyze
descriptions of the halo mass function in chameleon f(R) gravity using a mass-
and environment-dependent spherical collapse model in combination with
excursion set theory and phenomenological fits to N-body simulations in the
LCDM and f(R) gravity scenarios. Our halo mass functions consistently
incorporate the chameleon suppression and cosmological parameter dependencies,
improving upon previous formalisms and providing an important extension to
N-body simulations for the application in consistent tests of gravity with
observables sensitive to the abundance of clusters.


title:
Exact expressions for the pericenter precession caused by some Dark
  Matter distributions and constraints on them from orbital motions in the
  Solar System, in the double pulsar and in the Galactic center

abstract:
  We analytically calculate the secular precession of the pericenter of a test
particle orbiting a central body surrounded by a continuous distribution of
Dark Matter (DM) by using some commonly adopted density profiles for it. We
obtain exact expressions without resorting to a-priori simplifying assumptions
on the orbital geometry of the test particle. Our formulas allow us to put
constraints on the parameters of the DM distributions considered in several
local astronomical and astrophysical scenarios, such as the Sun's planetary
system, the double pulsar, and the stellar system around the supermassive black
hole in Sgr A$^{\ast}$, all characterized by a wide variety of orbital
configurations.


title:
PS1-10jh: The Disruption of a Main-Sequence Star of Near-Solar
  Composition

abstract:
  When a star comes within a critical distance to a supermassive black hole
(SMBH), immense tidal forces disrupt the star, resulting in a stream of debris
that falls back onto the SMBH and powers a luminous flare. In this paper, we
perform hydrodynamical simulations of the disruption of a main-sequence star by
a SMBH to characterize the evolution of the debris stream after a tidal
disruption. We demonstrate that this debris stream is confined by self-gravity
in the two directions perpendicular to the original direction of the star's
travel, and as a consequence has a negligible surface area and makes almost no
contribution to either the continuum or line emission. We therefore propose
that any observed emission lines are not the result of photoionization in this
unbound debris, but are produced in the region above and below the forming
elliptical accretion disk, analogous to the broad-line region (BLR) in
steadily-accreting active galactic nuclei. As each line within a BLR is
observationally linked to a particular location in the accretion disk, we
suggest that the absence of a line indicates that the accretion disk does not
yet extend to the distance required to produce that line. This model can be
used to understand the spectral properties of the tidal disruption event (TDE)
PS1-10jh, for which He II lines are observed, but the Balmer series and He I
are not. Using a maximum likelihood analysis, we show that the disruption of a
main-sequence star of near-solar composition can reproduce this event.


title:
Lightcurves of Stars & Exoplanets: Estimating Inclination, Obliquity,
  and Albedo

abstract:
  [Abridged] Distant stars and planets will remain spatially unresolved for the
foreseeable future. It is nonetheless possible to infer aspects of their
brightness markings and viewing geometries by analyzing disk-integrated
rotational and orbital brightness variations. We compute the harmonic
lightcurves, F_l^m(t), resulting from spherical harmonic maps of intensity or
albedo, Y_l^m(theta,phi), where l and m are the total and longitudinal order.
Notably, odd m>1 are present in an inclined lightcurve, but not seen by an
equatorial observer. We therefore suggest that the Fourier spectrum of a
thermal lightcurve may be sufficient to determine the orbital inclination of
non-transiting short-period planets, the rotational inclination of stars and
brown dwarfs, and the obliquity of directly imaged planets. In the best-case
scenario of a nearly edge-on geometry, measuring the m=3 mode of a star's
rotational lightcurve to within a factor of two provides an inclination
estimate good to +/- 6 degrees, assuming stars have randomly distributed spots.
Alternatively, if stars have brightness maps perfectly symmetric about the
equator, their lightcurves will have no m=3 power, regardless of orientation.
In general, inclination estimates will remain qualitative until detailed
hydrodynamic simulations and/or occultation maps can be used as a calibrator.
We further derive harmonic reflected lightcurves for tidally-locked planets;
these are higher-order versions of the well-known Lambert phase curve. We show
that a non-uniform planet may have an apparent albedo 25% lower than its
intrinsic albedo, even if it exhibits precisely Lambertian phase variations.
Lastly, we provide low-order analytic expressions for harmonic lightcurves that
can be used for fitting observed photometry; as a general rule, edge-on
solutions cannot simply be scaled by sin(i) to mimic inclined lightcurves.


title: Small non-Gaussianity and dipole asymmetry in the CMB

abstract:
  In this paper we provide a prescription for obtaining a small non-Gaussianity
and the observed dipole asymmetry in the cosmic microwave background radiation.
The observations inevitably lead to multi-field inflationary dynamics, where
each field can create positive or negative large non-Gaussianity, resulting a
fine cancellation but with an observable imprint on the hemispherical
asymmetry. We discuss this possibility within a simple slow-roll scenario and
find that it is hard to explain the observed dipole asymmetry. We briefly
discuss some speculative scenarios where one can explain dipole asymmetry.


title:
Energy dependent power spectral states and origin of aperiodic
  variability in black hole binaries

abstract:
  We found the black hole candidate MAXI J1659-152 showed distinct power
spectra, i.e., a power-law noise (PLN) vs. band-limited noise (BLN) plus
quasi-periodic oscillations (QPOs), below and above about 2 keV respectively,
in the observations with the Swift and the RXTE during the 2010 outburst,
indicating a high energy cut-off of the PLN and a low energy cut-off of the BLN
and the QPOs around 2 keV. The emergence of the PLN and the fading of the BLN
and the QPOs initially took place from below 2 keV when the source entered the
hard intermediate state and finally settled in the soft state three weeks
later. The evolution was accompanied by the emergence of the disk spectral
component and decreases in the amplitudes of variability in the soft X-ray and
the hard X-ray bands. Our results indicate that the PLN is associated with the
optically thick disk in both hard and intermediate states, and power spectral
state is independent of the X-ray energy spectral state in a broadband view. We
suggest that in the hard and the intermediate state, the BLN and the QPOs
emerge from the innermost hot flow subjected to Comptonization, while the PLN
originates from the optically thick disk further out. The energy cut-offs of
the PLN and the BLN or QPOs then follow the temperature of the seed photons
from the inner edge of the optically thick disk, while the high frequency
cut-off of the PLN follows the orbital frequency at the inner edge of the
optically thick disk as well.


title:
Connecting Direct Dark Matter Detection Experiments to Cosmologically
  Motivated Halo Models

abstract:
  Several direct detection experiments, including recently CDMS-II, have
reported signals consistent with 5 to 10 GeV dark matter (DM) that appear to be
in tension with null results from XENON and LUX experiments; these indicate a
careful review of the theoretical basis, including the galactic DM velocity
distribution function (VDF). We establish a VDF parameter space from DM-only
cosmological simulations and illustrate that seemingly contradictory
experimental results can be made consistent within this parameter space. Future
experimental limits should be reported after they are marginalized over a range
of VDF parameters.


title: Structure of entanglement in regulated Lorentz invariant field theories

abstract:
  Regulated Lorentz invariant quantum field theories satisfy an area law for
the entanglement entropy $S$ of a spatial subregion in the ground state in
$d>1$ spatial dimensions; nevertheless, the full density matrix contains many
more than $e^{S}$ non-zero eigenvalues. We ask how well the state of a
subregion $R$ in the ground state of such a theory can be approximated when
keeping only the $e^{S}$ largest eigenvalues of the reduced density matrix of
$R$. We argue that by taking the region $R$ big enough, we can always ensure
that keeping roughly $e^{S}$ states leads to bounded error in trace norm even
for subregions in gapless ground states. We support these general arguments
with an explicit computation of the error in a half-space geometry for a free
scalar field in any dimension. Along the way we show that the Renyi entropy of
a ball in the ground state of any conformal field theory at small Renyi
parameter is controlled by the conventional \textit{thermal entropy density} at
low temperatures. We also reobtain and generalize some old results relevant to
DMRG on the decay of Schmidt coefficients of intervals in one dimensional
ground states. Finally, we discuss the role of the regulator, the insensitivity
of our arguments to the precise ultraviolet physics, and the role of adiabatic
continuity in our results.


title: On the Lira law and the nature of extinction towards Type Ia Supernovae

abstract:
  We have studied the relation between the color evolution of Type Ia
Supernovae (SNe Ia) from maximum light to the Lira law regime and the presence
of narrow absorption features. Based on a nearby sample of 89 SNe Ia we have
found that the rate of change of B-V colors at late phases (between 35 and 80
days after maximum) varies significantly among different SNe Ia. At maximum
light, faster Lira law B-V decliners have significantly higher equivalent
widths of blended Na I D1 & D2 narrow absorption lines, redder colors and lower
R_V reddening laws. We do not find faster Lira law B-V decliners to have a
strong preference for younger galaxy environments, where higher interstellar
material (ISM) column densities would be expected. We interpret these results
as evidence for the presence of circumstellar material (CSM). The differences
in colors and reddening laws found at maximum light are also present 55 days
afterward, but unlike the colors at maximum, they show a significant variation
among different host galaxy morphological types. This suggests that the effect
of ISM on the colors is more apparent at late times. Finally, we discuss how
the transversal expansion of the ejecta in an inhomogeneous ISM could mimic
some of these findings.


title:
The spectral evolution of the first galaxies. II. Spectral signatures of
  Lyman continuum leakage from galaxies in the reionization epoch

abstract:
  The fraction of ionizing photons (fesc) that escape from z>6 galaxies is an
important parameter when assessing the role of these objects in the
reionization of the Universe, but the opacity of the intergalactic medium
precludes a direct measurement of fesc for individual galaxies at these epochs.
We argue, that since fesc regulates the impact of nebular emission on the
spectra of galaxies, it should nonetheless be possible to indirectly probe fesc
well into the reionization epoch. As a first step, we demonstrate that by
combining measurements of the rest-frame UV slope beta with the equivalent
width of the Hb emission line, galaxies with very high Lyman continuum escape
fractions (fesc>0.5) should be identifiable up to z~9 through spectroscopy with
the upcoming James Webb Space Telescope (JWST). By targeting strongly lensed
galaxies behind low-redshift galaxy clusters, JWST spectra of sufficiently good
quality can be obtained for M(1500)<-16.0 galaxies at z~7 and for M(1500)<-17.5
galaxies at z~9. Dust-obscured star formation may complicate the analysis, but
supporting observations with ALMA or the planned SPICA mission may provide
useful constraints on the dust properties of these galaxies.


title: Scattered Emission from z~1 Galactic Outflows

abstract:
  Mapping Mg II resonance emission scattered by galactic winds offers a means
to determine the spatial extent and density of the warm outflow. Using
Keck/LRIS spectroscopy, we have resolved scattered Mg II emission to the east
of 32016857, a star-forming galaxy at z =0.9392 with an outflow. The Mg II
emission from this galaxy exhibits a P-Cygni profile, extends further than both
the continuum and [O II] emission along the eastern side of the slit, and has a
constant Doppler shift along the slit which does not follow the velocity
gradient of the nebular [O II] emission. Using the Sobolev approximation, we
derive the density of Mg+ ions at a radius of 12 to 18 kpc in the outflow. We
model the ionization correction and find that much of the outflowing Mg is in
Mg++. We estimate that the total mass flux could be as large as 330 - 500 solar
masses per year, with the largest uncertainties coming from the depletion of Mg
onto grains and the clumpiness of the warm outflow. We show that confining the
warm clouds with a hot wind reduces the estimated mass flux of the warm outflow
and indicates amass-loading factor near unity in the warm phase alone. Based on
the high blue luminosities that distinguish 32016857 and TKRS 4389, described
by Rubin et al. 2011, from other galaxies with P-Cygni emission, we suggest
that, as sensitivity to diffuse emission improves, scattering halos may prove
to be a generic property of star-forming galaxies at intermediate redshifts.


title:
Superconducting and Pseudogap effects on the interplane conductivity and
  Raman scattering cross section in the two dimensional Hubbard Model

abstract:
  Cluster dynamical mean field methods are used to calculate the
superconductivity-induced changes in the interplane conductivity and Raman
scattering cross section of the two dimensional Hubbard model. When
superconductivity emerges from the pseudogap, the superconducting response is
found to be diminished in amplitude, broadened and, in the case of the
interplane conductivity, shifted to higher frequency. The results are in
agreement with data on high temperature copper-oxide superconductors indicating
that the Hubbard model contains the essential low energy physics of the
pseudogap and its interplay with superconductivity in the cuprates.


title:
Why Comparable? A Multiverse Explanation of the Dark Matter-Baryon
  Coincidence

abstract:
  The densities of dark and baryonic matter are comparable: \zeta = \rho_D /
\rho_B ~ O(1). This is surprising because they are controlled by different
combinations of low-energy physics parameters. Here we consider the probability
distribution over \zeta in the landscape. We argue that the Why Comparable
problem can be solved without detailed anthropic assumptions, and independently
of the nature of dark matter. Overproduction of dark matter suppresses the
probability like 1/(1+\zeta), if the causal patch is used to regulate
infinities. This suppression can counteract a prior distribution favoring large
\zeta, selecting \zeta ~ O(1).
  This effect not only explains the Why Comparable coincidence but also renders
otherwise implausible models of dark matter viable. For the special case of
axion dark matter, Wilczek and independently Freivogel have already noted that
a 1/(1+\zeta) suppression prevents overproduction of a GUT-scale QCD axion. If
the dark matter is the LSP, the effect can explain the moderate fine-tuning of
the weak scale in simple supersymmetric models.


title: Lagrangian Formulation of Stochastic Inflation: A Recursive Approach

abstract:
  We present a new, recursive approach to stochastic inflation which is
self-consistent and solves multiple problems which plagued a certain number of
previous studies, in particular in realistic contexts where the background
spacetime is taken to be dynamical, where there is more than one field present,
especially with a mass hierarchy, or where the role played by back-reaction is
suspected to be important. We first review the formalism of stochastic
inflation as it is usually heuristically presented, that is, deriving the
Langevin equations from the field equations of motion, and summarize previous
results on the subject. We demonstrate where inconsistent approximations to the
Langevin equations are commonly made, and show how these can be avoided. This
set up shares many similarities with quantum Brownian motion and
out-of-equilibrium statistical quantum dynamics. We hence review how path
integral techniques can be applied to the stochastic inflationary context. We
show this formalism to be consistent with the standard approach, develop a
natural perturbative expansion, and use it to calculate the one-loop corrected
Langevin equations.


title: Ultraviolet asymptotics of glueball propagators

abstract:
  We point out that perturbation theory in conjunction with the renormalization
group (RG) puts a severe constraint on the structure of the large-N
non-perturbative glueball propagators in SU(N) pure YM, in QCD and in n=1 SUSY
QCD with massless quarks, or in any confining asymptotically-free gauge theory
massless in perturbation theory. For the scalar and pseudoscalar glueball
propagators in pure YM and QCD with massless quarks we check in detail the
RG-improved estimate to the order of the leading and next-to-leading logarithms
by means of a remarkable three-loop computation by Chetyrkin et al. We
investigate as to whether the aforementioned constraint is satisfied by any of
the scalar or pseudoscalar glueball propagators computed in the framework of
the AdS String/ large-N Gauge Theory correspondence and of a recent proposal
based on a Topological Field Theory underlying the large-N limit of YM. We find
that none of the proposals for the scalar or the pseudoscalar glueball
propagators based on the AdS String/ large-N Gauge Theory correspondence
satisfies the constraint, actually as expected, since the gravity side of the
correspondence is in fact strongly coupled in the ultraviolet. On the contrary,
the Topological Field Theory satisfies the constraint that follows by the
asymptotic freedom.


title: Charged elliptic flow at zero charge asymmetry

abstract:
  The difference between the flow ellipticities of oppositely charged pions,
\Delta v_2=v_2[\pi-]-v_2[\pi+], measured recently by STAR collaboration at RHIC
shows a linear dependence on the event charge asymmetry A_+-={(N_+-N_-)/
(N_++N_-)}: \Delta v_2(A_+-)= \Delta v_2(0)+ r A_+- with a slope r>0 and a
non-zero intercept \Delta v_2(0)>0 of order 10^{-4}. We point out two novel
mechanisms which could explain the non-zero value of the charged elliptic flow
\Delta v_2 at zero charge asymmetry A_+-=0, i.e., the non-zero positive
intercept \Delta v_2(0). Both effects are due to the electric fields created by
the colliding ions. These fields have quadrupole asymmetry of the magnitude and
the sign needed to account for the nonzero intercept \Delta v_2(0) in the RHIC
data. One of the mechanisms also involves chiral magnetic effect. This
mechanism, although negligible at RHIC energies, may become important at LHC
energies.


title:
The scale-dependent signature of primordial non-Gaussianity in the
  large-scale structure of cosmic reionization

abstract:
  (ABRIDGED)The rise of cosmic structure depends upon the statistical
distribution of initial density fluctuations generated by inflation. While the
simplest models predict an almost perfectly Gaussian distribution, more-general
models predict a level of primordial non-Gaussianity (PNG) that observations
might yet be sensitive enough to detect. Recent Planck Collaboration
measurements of the CMB temperature anisotropy bispectrum significantly tighten
the observational limits, but they are still far from the PNG level predicted
by the simplest models of inflation. Probing levels below CMB sensitivities
will require other methods, such as searching for the statistical imprint of
PNG on galactic halo clustering. During the epoch of reionization (EoR), the
first stars and galaxies released radiation into the intergalactic medium (IGM)
that created ionized patches whose large-scale geometry and evolution reflected
the underlying abundance and large-scale clustering of the star-forming
galaxies. This statistical connection between ionized patches in the IGM and
galactic halos suggests that observing reionization may be another way to
constrain PNG. We employ the linear perturbation theory of reionization and
semi-analytic models based on the excursion-set formalism to model the effects
of PNG on the EoR. We quantify the effects of PNG on the large-scale structure
of reionization by deriving the ionized density bias, i.e. ratio of ionized
atomic to total matter overdensities in Fourier space, at small wavenumber.
Just as previous studies found that PNG creates a scale-dependent signature in
the halo bias, so, too, we find a scale-dependent signature in the ionized
density bias. Our results, which differ significantly from previous attempts in
the literature to characterize this PNG signature, will be applied elsewhere to
predict its observable consequences, e.g. in the cosmic 21cm background.


title: Eight New Radio Pulsars in the Large Magellanic Cloud

abstract:
  We present the discovery of eight new radio pulsars located in the Large
Magellanic Cloud (LMC). Five of these pulsars were found from reprocessing the
Parkes Multibeam Survey of the Magellanic Clouds, while the remaining three
were from an ongoing new survey at Parkes with a high resolution data
acquisition system. It is possible that these pulsars were missed in the
earlier processing due to radio frequency interference, visual judgment, or the
large number of candidates that must be analysed. One of these new pulsars has
a dispersion measure of 273 pc cm$^{-3}$, almost twice the highest previously
known value, making it possibly the most distant LMC pulsar. In addition, we
present the null result of a radio pulse search of an X-ray point source
located in SNR J0047.2$-$7308 in the Small Magellanic Cloud (SMC). Although no
millisecond pulsars have been found, these discoveries have increased the known
rotation powered pulsar population in the LMC by more than 50%. Using the
current sample of LMC pulsars, we used a Bayesian analysis to constrain the
number of potentially observable pulsars in the LMC to within a 95% credible
interval of 57000$^{+70000}_{-30000}$. The new survey at Parkes is $\sim$20%
complete and it is expected to yield at most six millisecond pulsars in the LMC
and SMC. Although it is very sensitive to short period pulsars, this new survey
provides only a marginal increase in sensitivity to long periods. The limiting
luminosity for this survey is 125 mJy kpc$^2$ for the LMC which covers the
upper 10% of all known radio pulsars. The luminosity function for normal
pulsars in the LMC is consistent with their counterparts in the Galactic disk.
The maximum 1400 MHz radio luminosity for LMC pulsars is $\sim 1000$ mJy
kpc$^2$.


title: On the Diophantine equation N X^2 + 2^L 3^M = Y^N

abstract:
  We prove that the Diophantine equation N X^2 + 2^L 3^M = Y^N has no solutions
(N,X,Y,L,M) in positive integers with N > 1 and gcd(NX,Y) = 1, generalizing
results of Luca, Wang and Wang, and Luca and Soydan. Our proofs use results of
Bilu, Hanrot, and Voutier on defective Lehmer pairs.


title: Unravelling $t\bar{t}h$ via the matrix element method

abstract:
  Associated production of the Higgs boson with a top-antitop pair is a key
channel to gather further information on the nature of the newly discovered
boson at the LHC. Experimentally, however, its observation is very challenging
due to the combination of small rates, difficult multi-jet final states and
overwhelming backgrounds. In the Standard Model the largest number of events is
expected when h->bb, giving rise to a WWbbbb signature, deluged in tt+jets. A
promising strategy to improve the sensitivity is to maximally exploit the
theoretical information on the signal and background processes by means of the
matrix element method. We show how, despite the complexity of the final state,
the method can be efficiently applied to discriminate the signal against
combinatorial and tt+jets backgrounds. Remarkably, we find that a moderate
integrated luminosity in the next LHC run will be enough to make the signature
involving both W's decaying leptonically as sensitive as the single-lepton one.


title:
Absence of static orbital current magnetism at the apical oxygen site in
  HgBa$_2$CuO$_{4+\delta}$ from NMR

abstract:
  The simple structure of HgBa$_2$CuO$_{4+\delta}$ (Hg1201) is ideal among
cuprates for study of the pseudogap phase as a broken symmetry state. We have
performed $^{17}$O nuclear magnetic resonance (NMR) on an underdoped Hg1201
crystal with transition temperature of 74 K to look for circulating orbital
currents proposed theoretically and inferred from neutron scattering. The
narrow spectra preclude static local fields in the pseudogap phase at the
apical site, suggesting that the moments observed with neutrons are
fluctuating. The NMR frequency shifts are consistent with a dipolar field from
the Cu$^{+2}$ site.


title:
Equilibration of Small and Large Subsystems in Field Theories and Matrix
  Models

abstract:
  It has been recently shown that small subsystems of finite quantum systems
generically equilibrate. We extend these results to infinite-dimensional
Hilbert spaces of field theories and matrix models. We consider a quench setup,
where initial states are chosen from a microcanonical ensemble of finite energy
in free theory, and then evolve with an arbitrary non-perturbative Hamiltonian.
Given a dynamical assumption on the expectation value of particle number
density, we prove that small subsystems reach equilibrium at the level of
quantum wave-function, and with respect to all observables. The picture that
emerges is that at higher energies, larger subsystems can reach equilibrium.
For bosonic fields on a lattice, in the limit of large number of bosons per
site, all subsystem smaller than half equilibrate. In the Hermitian matrix
model, by contrast, this occurs in the limit of large energy per matrix
element, emphasizing the importance of the $O(N^2)$ energy scale for the fast
scrambling conjecture. Applying our techniques to continuum field theories on
compact spaces, we show that the density matrix of small momentum-space
observables equilibrate. Finally, we discuss the connection with scrambling,
and provide a sufficient condition for a time-independent Hamiltonian to be a
scrambler in terms of the entanglement entropy of its energy eigenstates.


title:
Finite temperature Casimir effect for charged massless scalars in a
  magnetic field

abstract:
  The zeta function regularization technique is used to study the finite
temperature Casimir effect for a charged and massless scalar field confined
between parallel plates and satisfying Dirichlet boundary conditions at the
plates. A magnetic field perpendicular to the plates is included. Three
equivalent expressions for the zeta function are obtained, which are exact to
all orders in the magnetic field strength, temperature and plate distance.
These expressions of the zeta function are used to calculate the Helmholtz free
energy of the scalar field and the pressure on the plates, in the case of high
temperature, small plate distance and strong magnetic field. In all cases,
simple analytic expressions are obtained for the free energy and pressure which
are accurate and valid for practically all values of temperature, plate
distance and magnetic field.


title:
The four-loop cusp anomalous dimension in N=4 super Yang-Mills and
  analytic integration techniques for Wilson line integrals

abstract:
  Correlation functions of Wilson lines are relevant for describing the
infrared structure of scattering amplitudes. We develop a new method for
evaluating a wide class of such Wilson line integrals, and apply it to the
calculation of the velocity-dependent cusp anomalous dimension in maximally
supersymmetric Yang-Mills theory. We compute the four-loop non-planar
correction in a recently introduced scaling limit. Moreover, we derive the full
planar four-loop result by means of an ansatz which is based on the structure
of known analytic results. We determine the coefficients in this ansatz by
making use of a relationship to massive scattering amplitudes. As a corollary,
our analytical result confirms the four-loop value of the light-like cusp
anomalous dimension. Finally, we use the available perturbative data, as well
as insight from AdS/CFT, in order to extrapolate the leading order values at
strong coupling. The latter agree within two per cent with the corresponding
string theory result, over a wide range of parameters.


title: Granular Dynamics during Impact

abstract:
  We study the impact of a projectile onto a bed of 3 mm grains immersed in an
index-matched fluid. Specifically, we vary the amount of prestrain on the
sample, strengthening the force chains within the system. We find this affects
only the prefactor of linear depth-dependent term in the stopping force. We
therefore attribute this term to pressure within the material, and not the
grain-intruder friction as is sometimes suggested. Using a laser sheet scanning
technique to visualize internal grain motion, a high-speed camera, and particle
tracking, we can measure the trajectory of each grain throughout an impact
event. Microscopically, our results indicate that weaker initial force chains
result in more irreversible, plastic rearrangements during impact, suggesting
static friction between grains does play a substantial role in the energy
dissipation within the granular material.


title: Preventing Unraveling in Social Networks Gets Harder

abstract:
  The behavior of users in social networks is often observed to be affected by
the actions of their friends. Bhawalkar et al. \cite{bhawalkar-icalp}
introduced a formal mathematical model for user engagement in social networks
where each individual derives a benefit proportional to the number of its
friends which are engaged. Given a threshold degree $k$ the equilibrium for
this model is a maximal subgraph whose minimum degree is $\geq k$. However the
dropping out of individuals with degrees less than $k$ might lead to a
cascading effect of iterated withdrawals such that the size of equilibrium
subgraph becomes very small. To overcome this some special vertices called
"anchors" are introduced: these vertices need not have large degree. Bhawalkar
et al. \cite{bhawalkar-icalp} considered the \textsc{Anchored $k$-Core}
problem: Given a graph $G$ and integers $b, k$ and $p$ do there exist a set of
vertices $B\subseteq H\subseteq V(G)$ such that $|B|\leq b, |H|\geq p$ and
every vertex $v\in H\setminus B$ has degree at least $k$ is the induced
subgraph $G[H]$. They showed that the problem is NP-hard for $k\geq 2$ and gave
some inapproximability and fixed-parameter intractability results. In this
paper we give improved hardness results for this problem. In particular we show
that the \textsc{Anchored $k$-Core} problem is W[1]-hard parameterized by $p$,
even for $k=3$. This improves the result of Bhawalkar et al.
\cite{bhawalkar-icalp} (who show W[2]-hardness parameterized by $b$) as our
parameter is always bigger since $p\geq b$. Then we answer a question of
Bhawalkar et al. \cite{bhawalkar-icalp} by showing that the \textsc{Anchored
$k$-Core} problem remains NP-hard on planar graphs for all $k\geq 3$, even if
the maximum degree of the graph is $k+2$. Finally we show that the problem is
FPT on planar graphs parameterized by $b$ for all $k\geq 7$.


title: Kumjian-Pask algebras of locally convex higher-rank graphs

abstract:
  The Kumjian-Pask algebra of a higher-rank graph generalises the Leavitt path
algebra of a directed graph. We extend the definition of Kumjian-Pask algebra
to row-finite higher-rank graphs $\Lambda$ with sources which satisfy a
local-convexity condition. After proving versions of the graded-uniqueness
theorem and the Cuntz-Krieger uniqueness theorem, we study the Kumjian-Pask
algebra of rank-2 Bratteli diagrams by studying certain finite subgraphs which
are locally convex. We show that the desourcification procedure of Farthing and
Webster yields a row-finite higher-rank graph $\tilde{\Lambda}$ without sources
such that the Kumjian-Pask algebras of $\tilde{\Lambda}$ and $\Lambda$ are
Morita equivalent. We then use the Morita equivalence to study the ideal
structure of the Kumjian-Pask algebra of $\Lambda$ by pulling the appropriate
results across the equivalence.


title: The type II superstring to order theta^4

abstract:
  The Green-Schwarz superstring action in a general type IIA or IIB
supergravity background is derived up to fourth order in the Grassmann-odd
coordinates theta. This is done by solving the superspace Bianchi identities
order by order in theta, to quadratic order for all superfields and to quartic
order for the supervielbeins. For a large class of backgrounds it is possible
to fix the kappa symmetry in such a way that the action actually terminates at
the quartic order in theta.


title:
Encapsulation of a fiber taper coupled microtoroid resonator in a
  polymer matrix

abstract:
  We encapsulated a high-quality (Q) factor optical whispering gallery mode
(WGM) microtoroid resonator together with its side coupled fiber taper inside a
low refractive index polymer, achieving a final Q higher than 10^7. Packaging
provides stable resonator-fiber taper coupling, long-term maintenance of
high-Q, a protective layer against contaminants, and portability to microtoroid
resonator based devices. We tested the robustness of the packaged device under
various conditions and demonstrated its capability for thermal sensing.


title:
Low-energy bound states at interfaces between superconducting and block
  antiferromagnet regions in KxFe{2-y}Se2

abstract:
  The high-Tc alkali doped iron selenide superconductors KxFe{2-y}Se2 have been
recently shown to be intrinsically phase separated into Fe vacancy ordered
block antiferromagnetic regions and superconducting regions at low
temperatures. In this work, we use a microscopic five orbital Hubbard model to
obtain the electronic low-energy states near the interfaces between block
antiferromagnets and superconductors. It is found that abundant low-energy
in-gap bound states exist near such interfaces irrespective of whether the
superconductor has d- or s-wave pairing symmetry. By contrast, it is shown how
nonmagnetic scattering planes can provide a natural means to distinguish
between these two leading pairing instabilities of the KxFe{2-y}Se2 materials.


title:
Lack of measurement independence can simulate quantum correlation even
  when signaling cannot

abstract:
  In Bell scenario, any nonlocal correlation, shared between two spatially
separated parties, can be modeled deterministically either by allowing
communications between the two parties or by restricting their free will in
choosing the measurement settings. Recently, Bell scenario has been generalized
into `semi-quantum' scenario where external quantum inputs are provided to the
parties. We show that in `semi-quantum' scenario, entangled states produce
correlations whose deterministic explanation is possible only if measurement
independence is reduced. Thus in simulating quantum correlation `semi-quantum'
scenario reveals a qualitative distinction between signaling and measurement
dependence which is absent in Bell scenario. We further show that such
distinction is not observed in `steering game' scenario, a special case of
`semi-quantum' scenario.


title:
Central limit theorem for an additive functional of the fractional
  Brownian motion II

abstract:
  We prove a central limit theorem for an additive functional of the
$d$-dimensional fractional Brownian motion with Hurst index
$H\in(\frac{1}{2+d},\frac{1}{d})$, using the method of moments, extending the
result by Papanicolaou, Stroock and Varadhan in the case of the standard
Brownian motion.


title: 3D kinematics through the X-shaped Milky Way bulge

abstract:
  It has recently been discovered that the Galactic bulge is X-shaped, with the
two southern arms of the X both crossing the lines of sight at l=0 and |b|>4,
hence producing a double red clump (RC) in the bulge CMD. Dynamical models
predict the formation of X-shaped bulges, as extreme cases of boxy-peanut
bulges. However, since X-shaped bulges were known to be present only in
external galaxies, models have never been compared to 3D kinematical data for
individual stars. We study the orbital motion of Galactic bulge stars, in the
two arms of the X in the southern hemisphere. The goal is to provide
observational constraints to bulge formation models that predict the formation
of X-shapes through bar dynamical instabilities. Radial velocities have been
obtained for a sample of 454 bulge giants, roughly equally distributed between
the bright and faint RC, in a field at (l,b)=(0,-6). Proper motions were
derived for all RC stars in the same field by combining images from two epochs
obtained 11 years apart. The proper motions for the spectroscopic subsample are
analyzed taking into account the radial velocities and metallicities measured
from near-IR Calcium triplet lines, for a subsample of 352 stars. The radial
velocity distribution of stars in the bright RC, tracing the closer overdensity
of bulge stars, shows an excess of stars moving towards the Sun. Similarly, an
excess of stars receding from the Sun is seen in the far overdensity, traced by
faint RC stars. This is explained with the presence of stars on elongated
orbits, most likely streaming along the arms of the X-shaped bulge. Proper
motions for these stars are consistent with qualitative predictions of
dynamical models of peanut-shaped bulges. Surprisingly, stars on elongated
orbits have preferentially metal poor metallicities, while the metal rich ones,
in both overdensities, are preferentially found in more axysimmetric orbits.


title:
Non-relativistic radiation mediated shock breakouts: III. Spectral
  properties of SN shock breakout

abstract:
  The spectrum of radiation emitted following shock breakout from a star's
surface with a power-law density profile $\rho \propto x^n$ is investigated.
Assuming planar geometry, local Compton equilibrium and bremsstrahlung emission
as the dominant photon production mechanism, numerical solutions are obtained
for the photon number density and temperature profiles as a function of time,
for hydrogen-helium envelopes. The temperature solutions are determined by the
breakout shock velocity $v_0$ and the pre-shock breakout density $\rho_0$, and
depend weakly on the value of n. Fitting formulas for the peak surface
temperature at breakout as a function of $v_0$ and $\rho_0$ are provided, with
$T_{peak}\approx 9.44\exp{[12.63(v_0/c)^{1/2}]}$ eV, and the time dependence of
the surface temperature is tabulated. The time integrated emitted spectrum is a
robust prediction of the model, determined by $\mathcal{T}_{\rm peak}$ and
$v_0$ alone and insensitive to details of light travel time or slight
deviations from spherical symmetry. Adopting commonly assumed progenitor
parameters, breakout luminosities of ~10^45 erg/s and ~10^44 erg/s in the
0.3-10 keV band are expected for BSG and RSG/He-WR progenitors respectively
(T_{peak} is well below the band for RSGs, unless their radius is ~10^13 cm).
>30 detections of SN1987A-like (BSG) breakouts are expected over the lifetime
of ROSAT and XMM-Newton. An absence of such detections would imply that either
the typical parameters assumed for BSG progenitors are grossly incorrect or
that their envelopes are not hydrostatic. The observed spectrum and duration of
XRF 080109/SN2008D are in tension with a non-relativistic breakout from a
stellar surface interpretation.


title: Star Formation in High-Redshift Starburst Galaxies

abstract:
  I present a model for the star formation properties of z~2 starburst
galaxies. Here, I discuss models for the formation of high-z Submillimeter
Galaxies, as well as the CO-H2 conversion factor for these systems. I then
apply these models to literature observations. I show that when using a
functional form for XCO that varies smoothly with the physical properties in
galaxies, galaxies at both local and high-z lie on a unimodal Kennicutt-Schmidt
star formation law, with power-law index of ~2. The inferred gas fractions of
these galaxies are large (fgas ~ 0.2-0.4), though a factor ~2 lower than most
literature estimates that utilize locally-calibrated CO-H2 conversion factors.


title:
1 Hz Flaring in the Accreting Millisecond Pulsar NGC 6440 X-2: Disk
  Trapping and Accretion Cycles

abstract:
  The dynamics of the plasma in the inner regions of an accretion disk around
accreting millisecond X-ray pulsars is controlled by the magnetic field of the
neutron star. The interaction between an accretion disk and a strong magnetic
field is not well-understood, particularly at low accretion rates (the
so-called ``propeller regime'). This is due in part to the lack of clear
observational diagnostics to constrain the physics of the disk-field
interaction. Here we associate the strong ~1 Hz modulation seen in the
accreting millisecond X-ray pulsar NGC 6440 X-2 with an instability that arises
when the inner edge of the accretion disk is close to the corotation radius
(where the stellar rotation rate matches the Keplerian speed in the disk). A
similar modulation has previously been observed in another accreting
millisecond X-ray pulsar (SAX J1808.4-3658) and we suggest that the two
phenomena are related and that this may be a common phenomenon among other
magnetized systems. Detailed comparisons with theoretical models suggest that
when the instability is observed, the interaction region between the disk and
the field is very narrow -- of the order of 1 km. Modelling further suggests
that there is a transition region (~1-10 km) around the corotation radius where
the disk-field torque changes sign from spin up to spin down. This is the first
time that a direct observational constraint has been placed on the width of the
disk-magnetosphere interaction region, in the frame of the trapped-disk
instability model.


title: Properties of type Ia supernovae inside rich galaxy clusters

abstract:
  We used the GMBCG galaxy cluster catalogue and SDSS-II supernovae data with
redshifts measured by the BOSS project to identify 48 SNe Ia residing in rich
galaxy clusters and compare their properties with 1015 SNe Ia in the field.
Their light curves were parametrised by the SALT2 model and the significance of
the observed differences was assessed by a resampling technique. To test our
samples and methods, we first looked for known differences between SNe Ia
residing in active and passive galaxies. We confirm that passive galaxies host
SNe Ia with smaller stretch, weaker colour-luminosity relation [$\beta$ of
2.54(22) against 3.35(14)], and that are $\sim$ 0.1 mag more luminous after
stretch and colour corrections. We show that only 0.02 per cent of random
samples drawn from our set of SNe Ia in active galaxies can reach these values.
Reported differences in the Hubble residuals scatter could not be detected,
possibly due to the exclusion of outliers. We then show that, while most field
and cluster SNe Ia properties are compatible at the current level, their
stretch distributions are different ($\sim3\sigma$): besides having a higher
concentration of passive galaxies than the field, the cluster's passive
galaxies host SNe Ia with an average stretch even smaller than those in field
passive galaxies (at 95 per cent confidence). We argue that the older age of
passive galaxies in clusters is responsible for this effect since, as we show,
old passive galaxies host SNe Ia with smaller stretch than young passive
galaxies ($\sim4\sigma$).


title: Analytic Combinatorics of Planar Lattice Paths

abstract:
  Lattice paths effectively model phenomena in chemistry, physics and
probability theory. Asymptotic enumeration of lattice paths is linked with
entropy in the physical systems being modeled. Lattice paths restricted to
different regions of the plane are well suited to a functional equation
approach for exact and asymptotic enumeration. This thesis surveys results on
lattice paths under various restrictions, with an emphasis on lattice paths in
the quarter plane. For these paths, we develop an original systematic
combinatorial approach providing direct access to the exponential growth
factors of the asymptotic expressions.


title: $Z_c^+(3900)$ decay width in QCD sum rules

abstract:
  We identify the recently observed charmonium-like structure $Z_c^\pm(3900)$
as the charged partner of the X(3872) state. Using standard techniques of QCD
sum rules, we evaluate the three-point function and extract the coupling
constants of the $Z_c \, J/\psi \, \pi^+$ and $Z_c \, \eta_c \, \rho^+$
vertices and the corresponding decay widths in these channels. The good
agreement with the experimental data gives support to the tetraquark picture of
this state.


title:
Strain effects on the ionic conductivity of Y-doped ceria: A simulation
  study

abstract:
  In this paper we report a computational study of the effects of strain on the
conductivity of Y-doped ceria (YDC). This material was chosen as it is of
technological interest in the field of Solid Oxide Fuel Cells (SOFCs). The
simulations were performed under realistic operational temperatures and strain
(\epsilon) levels. For bulk and thin film YDC, the results show that tensile
strain leads to conductivity enhancements of up to 3.5x and 1.44x,
respectively. The magnitude of these enhancements is in agreement with recent
experimental and computational evidence. In addition, the methods presented
herein allowed us to identify enhanced ionic conductivity in the surface
regions of YDC slabs and its anisotropic character.


title: Division Point Measures from Primitive Substitutions

abstract:
  In this note we extend results of Olli concerning limits of point measures
arising from substitutions. We consider a general primitive substitution on a
finite polygon set in $\mathbb{R}^2$ and show that limits of certain atomic
measures each converge to Lebesgue measure.


title: Infinite Motion and 2-Distinguishability of Graphs and Groups

abstract:
  A group A acting faithfully on a set X is 2-distinguishable if there is a
2-coloring of X that is not preserved by any nonidentity element of A,
equivalently, if there is a proper subset of X with trivial setwise stabilizer.
The motion of an element a in A is the number of points of X that are moved by
a, and the motion of the group A is the minimal motion of its nonidentity
elements. For finite A, the Motion Lemma says that if the motion of A is large
enough (specifically at least 2 log_2 |A|), then the action is
2-distinguishable. For many situations where X has a combinatorial or algebraic
structure, the Motion Lemma implies the action of Aut(X) on X is
2-distinguishable in all but finitely many instances.
  We prove an infinitary version of the Motion Lemma for countably infinite
permutation groups, which states that infinite motion is large enough to
guarantee 2-distinguishability. From this we deduce a number of results,
including the fact that every locally finite, connected graph whose
automorphism group is countably infinite is 2-distinguishable. One cannot
extend the Motion Lemma to uncountable permutation groups, but nonetheless we
prove that 2-distinguishable permutation groups with infinite motion are dense
in the class of groups with infinite motion. We conjecture an extension of the
Motion Lemma which we expect holds for a restricted class of uncountable
permutation groups, and we conclude with a list of open questions. The
consequences of our results are drawn for orbit equivalence of infinite
permutation groups.


title: Faint End of 1.3 mm Number Counts Revealed by ALMA

abstract:
  We present the faint end of number counts at 1.3 mm (238 GHz) obtained with
the Atacama Large Millimeter/submillimeter Array (ALMA). Band 6 observations
were carried out targeting 20 star-forming galaxies at z ~ 1.4 in the
Subaru/XMM-Newton Deep Survey field. In the observations, we serendipitously
detect 15 sources (>=3.8 sigma, S(1.3 mm) = 0.15-0.61 mJy) other than the
targeted sources. We create number counts by using these `sub-mJy sources',
which probe the faintest flux range among surveys at millimeter wavelengths.
The number counts are consistent with (flux-scaled) number counts at 850 um and
870 um obtained with gravitational lensing clusters. The ALMA number counts
agree well with model predictions, which suggest that these sub-mJy populations
are more like `normal' star-forming galaxies than `classical' SMGs with intense
star-forming activity. In this flux range, ~80% of the extragalactic background
light at 1.3 mm is resolved into individual sources.


title:
Theoretical study of solid iron nanocrystal movement inside a carbon
  nanotube

abstract:
  We use a first-principles based kinetic Monte Carlo simulation to study the
movement of a solid iron nanocrystal inside a carbon nanotube driven by the
electrical current. The origin of the iron nanocrystal movement is the
electromigration force. Even though the iron nanocrystal appears to be moving
as a whole, we find that the core atoms of the nanocrystal is completely
stationary, and only the surface atoms are moving. Movement in the contact
region with the carbon nanotube is driven by electromigration forces, and the
movement on the remaining surfaces is driven by diffusion. Results of our
calculations also provide a simple model which can predict the center of mass
speed of the iron nanocrystal over a wide range of parameters. We find both
qualitative and quantitative agreement of the iron nanocrystal center of mass
speed with experimental data.


title: A palace for astronomy in Buenos Aires

abstract:
  In no other epoch of Western history like in the Middle Ages, cosmology was
so key an element of culture and, one way or another, the motion of the heavens
ended up impregnating the literature of that time. Among the most noteworthy
poets we find Dante Alighieri, who became famous for his Commedia, a monumental
poem written roughly between 1307 and his death in 1321, and which the critics
from XVIth century onwards dubbed Divina. In this and other works, Dante
pictures the cosmic image for the world, summing up the current trends of
Neoplatonic and Islamic traditions. The Barolo Palace in the city of Buenos
Aires is a singular combination of both astronomy and the worldview displayed
in Dante's poetic masterpiece. Some links of the Palace's main architectural
structure with the three realms of the Comedy have been studied in the past. In
this note we consider its unique astronomical flavor, an issue which has not
been sufficiently emphasized yet.


title: Smooth billiards with a large Weyl remainder

abstract:
  The celebrated Hardy-Landau lower bound for the error term in the Gauss's
circle problem can be viewed as an estimate from below for the remainder in
Weyl's law on a square, with either Dirichlet or Neumann boundary conditions.
We prove an analogous estimate for smooth star-shaped planar domains admitting
an appropriate one-parameter family of periodic billiard trajectories. Examples
include ellipses and smooth domains of constant width. Our results confirm a
prediction of P. Sarnak who proved a similar statement for surfaces without
boundary. We also obtain lower bounds on the error term in higher dimensions.
In this case, the main contribution to the Weyl remainder typically comes from
the "big" singularity at zero of the wave trace. However, for certain domains,
such as the Euclidean ball, the dimension of the family of periodic
trajectories is large enough to dominate the contribution of the singularity at
zero.


title:
Magnetic force microscopy study of the switching field distribution of
  low density arrays of single domain magnetic nanowires

abstract:
  In the present work, we report on the in situ magnetic force microscopy (MFM)
study of the magnetization reversal in two-dimensional arrays of ferromagnetic
Ni80Fe20 and Co55Fe45 nanowires(NW) with different diameters (40, 50, 70 and
100 nm) deposited inside low porosity (P<1%) nanoporous polycarbonate
membranes. In such arrays, the nanowires are sufficiently isolated from each
other so that long range dipolar interactions can be neglected. The MFM
experiments performed for different magnetization states at the same spot of
the samples are analysed to determine the switching field distribution (SFD).
The magnetization curves obtained from the MFM images are relatively square
shaped. The SFD widths are narrower compared to those obtained for high density
arrays. The weak broadening of the curves may be ascribed to the NW intrinsic
SFD. The influence of diameter and composition of the ferromagnetic NW is also
investigated.


title:
Verification of Inconsistency-Aware Knowledge and Action Bases (Extended
  Version)

abstract:
  Description Logic Knowledge and Action Bases (KABs) have been recently
introduced as a mechanism that provides a semantically rich representation of
the information on the domain of interest in terms of a DL KB and a set of
actions to change such information over time, possibly introducing new objects.
In this setting, decidability of verification of sophisticated temporal
properties over KABs, expressed in a variant of first-order mu-calculus, has
been shown. However, the established framework treats inconsistency in a
simplistic way, by rejecting inconsistent states produced through action
execution. We address this problem by showing how inconsistency handling based
on the notion of repairs can be integrated into KABs, resorting to
inconsistency-tolerant semantics. In this setting, we establish decidability
and complexity of verification.


title:
Measurement of the reaction O-17(\alpha,n)Ne-20 and its impact on the s
  process in massive stars

abstract:
  The ratio between the rates of the reactions O-17(\alpha,n)Ne-20 and
O-17(\alpha,\gamma)Ne-21 determines whether O-16 is an efficient neutron poison
for the s process in massive stars, or if most of the neutrons captured by
O-16(n,\gamma) are recycled into the stellar environment. This ratio is of
particular relevance to constrain the s process yields of fast rotating massive
stars at low metallicity. Recent results on the (\alpha,\gamma) channel have
made it necessary to measure the (\alpha,n) reaction more precisely and
investigate the effect of the new data on s process nucleosynthesis in massive
stars.
  We present a new measurement of the O-17(\alpha, n) reaction using a
moderating neutron detector. In addition, the (\alpha, n_1) channel has been
measured independently by observation of the characteristic 1633 keV
\gamma-transition in Ne-20. The reaction cross section was determined with a
simultaneous R-matrix fit to both channels. (\alpha,n) and (\alpha, \gamma)
resonance strengths of states lying below the covered energy range were
estimated using their known properties from the literature.
  A new O-17(\alpha,n) reaction rate was deduced for the temperature range 0.1
GK to 10 GK. It was found that in He burning conditions the (\alpha,\gamma)
channel is strong enough to compete with the neutron channel. This leads to a
less efficient neutron recycling compared to a previous suggestion of a very
weak (\alpha,\gamma) channel. S process calculations using our rates confirm
that massive rotating stars do play a significant role in the production of
elements up to Sr, but they strongly reduce the s process contribution to
heavier elements.


title: Vanishing dimensions: theory and phenomenology

abstract:
  Lower-dimensionality at higher energies has manifold theoretical advantages
as recently pointed out. Moreover, it appears that experimental evidence may
already exists for it - a statistically significant planar alignment of events
with energies higher than TeV has been observed in some earlier cosmic ray
experiments. If this alignment is not a fluke, then the LHC should be able to
see effects associated with the dimensional crossover. Further,
(2+1)-dimensional spacetimes have no gravitational degrees of freedom, and
gravity waves cannot be produced in that epoch in the early universe. This
places a universal maximum frequency at which primordial gravity waves can
propagate, which may be accessible to future gravitational wave detectors such
as LISA. In this talk, the theoretical motivation for "vanishing dimensions" as
well as generic experimental and observational signature will be discussed.


title: Skyscraper Numbers

abstract:
  We introduce numbers depending on three parameters which we call skyscraper
numbers. We discuss properties of these numbers and their relationship with
Stirling numbers of the first kind, and we also introduce a skyscraper
sequence.


title:
Numerical Integration of the Extended Variable Generalized Langevin
  Equation with a Positive Prony Representable Memory Kernel

abstract:
  Generalized Langevin dynamics (GLD) arise in the modeling of a number of
systems, ranging from structured fluids that exhibit a viscoelastic mechanical
response, to biological systems, and other media that exhibit anomalous
diffusive phenomena. Molecular dynamics (MD) simulations that include GLD in
conjunction with external and/or pairwise forces require the development of
numerical integrators that are efficient, stable, and have known convergence
properties. In this article, we derive a family of extended variable
integrators for the Generalized Langevin equation (GLE) with a positive Prony
series memory kernel. Using stability and error analysis, we identify a
superlative choice of parameters and implement the corresponding numerical
algorithm in the LAMMPS MD software package. Salient features of the algorithm
include exact conservation of the first and second moments of the equilibrium
velocity distribution in some important cases, stable behavior in the limit of
conventional Langevin dynamics, and the use of a convolution-free formalism
that obviates the need for explicit storage of the time history of particle
velocities. Capability is demonstrated with respect to accuracy in numerous
canonical examples, stability in certain limits, and an exemplary application
in which the effect of a harmonic confining potential is mapped onto a memory
kernel.


title: Dilatons in Dense Baryonic Matter

abstract:
  We discuss the role of dilaton, which is supposed to be representing a
special feature of scale symmetry of QCD, trace anomaly, in dense baryonic
matter. The idea that the scale symmetry breaking of QCD is responsible for the
spontaneous breaking of chiral symmetry is presented along the similar spirit
of Freund-Nambu model. The incorporation of dilaton field in the hidden local
symmetric parity doublet model is briefly sketched with the possible role of
dilaton at high density baryonic matter, the emergence of linear sigma model in
dilaton limit.


title: Representation of matroids with a modular plane

abstract:
  We prove that if M is a vertically 4-connected matroid with a modular flat X
of rank at least three, then every representation of M | X over a finite field
F extends to a unique F-representation of M. A corollary is that when F has
order q, any vertically 4-connected matroid with a PG(2, F)-restriction is
either F-representable or has a U_{2, q^2+1}-minor. We also show that no
excluded minor for the class of F-representable matroids has a PG(2,
F)-restriction.