title: Impact of QED radiative corrections on Parton Distribution Functions

abstract:
  The level of precision achieved by the experimental measurements at the LHC
requires the inclusion of higher order electroweak effects to the processes of
$ pp $ scattering. In particular the photon-induced process $ \gamma\gamma \to
\ell^+\ell^- $ make a significant contribution ($ \sim 10 \%$) to the dilepton
invariant mass distribution. To evaluate the cross-section of this process one
need to know the parton distribution function (PDF) of the photon in the proton
$ \gamma (x,\mu^2) $. The aim of the current study is to investigate the impact
of QED corrections on PDFs and describe the implementation of QED-modified
evolution equations into beta release of new version of {\tt QCDNUM} program.
The {\tt APPLGRID} interface to {\tt SANC} Monte Carlo generator for fast
evaluation of photon-induced cross-section is also outlined. The results were
cross-checked with {\tt partonevolution} program, {\tt MRST2004QED} PDF set and
{\tt APFEL} program. The described developments are planned to include into
{\tt HERAFitter} package and can be used to determine the photon PDF using new
data from the LHC experiments.


title: Light axial-vector tetraquark state candidate: $a_1(1420)$

abstract:
  In this article, we study the axial-vector tetraquark state and
two-quark-tetraquark mixed state consist of light quarks using the QCD sum
rules. The present predictions disfavor assigning the $a_1(1420)$ as the
axial-vector tetraquark state with $J^{PC}=1^{++}$, while support assigning the
$a_1(1420)$ as the axial-vector two-quark-tetraquark mixed state.


title: RXTE observations and state transition in MAXI J1836-194

abstract:
  We present the results of analysis of the X-ray transient source MAXI
J1836-194 during its outburst in August 2011. MAXI GSC detected the source on
30th August 2011, when it started rising from the quiescence. We have studied
the source using the observations of RXTE. In this paper, we study the temporal
and spectral evolution of the source during the outburst. Spectral analysis
shows that the source exhibits state transition to Hard Intermediate
state(HIMS) and decays back to a Low/Hard state. The temporal analysis
indicates the presence of QPOs during the hard intermediate state. We also
observe correlation between the evolution of break frequency with respect to
the spectral characteristics. We conclude that this is probably the second
source after H 1743-322 which exhibits transition to HIMS but does not reach
soft spectral state.


title:
Weak maser emission of methyl formate toward Sagittarius B2(N) in the
  Green Bank Telescope PRIMOS Survey

abstract:
  A non-LTE radiative transfer treatment of cis-methyl formate (HCOOCH3)
rotational lines is presented for the first time using a set of theoretical
collisional rate coefficients. These coefficients have been computed in the
temperature range 5-30 K by combining coupled-channel scattering calculations
with a high accuracy potential energy surface for HCOOCH3-He. The results are
compared to observations toward the Sagittarius B2(N) molecular cloud using the
publicly available PRIMOS survey from the Green Bank Telescope. A total of 49
low-lying transitions of methyl formate, with upper levels below 25 K, are
identified. These lines are found to probe a presumably cold (~30 K),
moderately dense (~1e4 cm-3) and extended region surrounding Sgr B2(N). The
derived column density of ~4e14 cm-2 is only a factor of ~10 larger than the
column density of the trans conformer in the same source. Provided that the two
conformers have the same spatial distribution, this result suggests that
strongly non-equilibrium processes must be involved in their synthesis.
Finally, our calculations show that all detected emission lines with a
frequency below 30 GHz are (collisionally pumped) weak masers amplifying the
continuum of Sgr B2(N). This result demonstrates the importance and generality
of non-LTE effects in the rotational spectra of complex organic molecules at
centimetre wavelengths.


title: Sparse graphs using exchangeable random measures

abstract:
  Statistical network modeling has focused on representing the graph as a
discrete structure, namely the adjacency matrix, and considering the
exchangeability of this array. In such cases, the Aldous-Hoover representation
theorem (Aldous, 1981;Hoover, 1979} applies and informs us that the graph is
necessarily either dense or empty. In this paper, we instead consider
representing the graph as a measure on $\mathbb{R}_+^2$. For the associated
definition of exchangeability in this continuous space, we rely on the
Kallenberg representation theorem (Kallenberg, 2005). We show that for certain
choices of such exchangeable random measures underlying our graph construction,
our network process is sparse with power-law degree distribution. In
particular, we build on the framework of completely random measures (CRMs) and
use the theory associated with such processes to derive important network
properties, such as an urn representation for our analysis and network
simulation. Our theoretical results are explored empirically and compared to
common network models. We then present a Hamiltonian Monte Carlo algorithm for
efficient exploration of the posterior distribution and demonstrate that we are
able to recover graphs ranging from dense to sparse--and perform associated
tests--based on our flexible CRM-based formulation. We explore network
properties in a range of real datasets, including Facebook social circles, a
political blogosphere, protein networks, citation networks, and world wide web
networks, including networks with hundreds of thousands of nodes and millions
of edges.


title:
Analysis of the Local Quasi-Stationarity of Measured Dual-Polarized MIMO
  Channels

abstract:
  It is common practice in wireless communications to assume strict or
wide-sense stationarity of the wireless channel in time and frequency. While
this approximation has some physical justification, it is only valid inside
certain time-frequency regions. This paper presents an elaborate
characterization of the non-stationarity of wireless dual-polarized channels in
time. The evaluation is based on urban macrocell measurements performed at 2.53
GHz. In order to define local quasi-stationarity (LQS) regions, i.e., regions
in which the change of certain channel statistics is deemed insignificant, we
resort to the performance degradation of selected algorithms specific to
channel estimation and beamforming. Additionally, we compare our results to
commonly used measures in the literature. We find that the polarization, the
antenna spacing, and the opening angle of the antennas into the propagation
channel can strongly influence the non-stationarity of the observed channel.
The obtained LQS regions can be of significant size, i.e., several meters, and
thus the reuse of channel statistics over large distances is meaningful (in an
average sense) for certain algorithms. Furthermore, we conclude that, from a
system perspective, a proper non-stationarity analysis should be based on the
considered algorithm.


title: Extensionality of lambda-*

abstract:
  We prove an extensionality theorem for the "type-in-type" dependent type
theory with Sigma-types. We suggest that the extensional equality type be
identified with the logical equivalence relation on the free term model of type
theory.


title:
Efficient random sampling of binary and unary-binary trees via holonomic
  equations

abstract:
  We present a new uniform random sampler for binary trees with $n$ internal
nodes consuming $2n + \Theta(\log(n)^2)$ random bits on average. This makes it
quasi-optimal and out-performs the classical Remy algorithm. We also present a
sampler for unary-binary trees with $n$ nodes taking $\Theta(n)$ random bits on
average. Both are the first linear-time algorithms to be optimal up to a
constant.


title:
Covariance in protein multiple sequence alignments using groups of
  columns

abstract:
  Algorithms that detect covariance between pairs of columns in multiple
sequence alignments are commonly employed to predict functionally important
residues and structural contacts. However, the assumption that co-variance only
occurs between individual residues in the protein is more driven by
computational convenience rather than fundamental protein architecture. Here we
develop a novel algorithm that defines a covariance score across two groups of
columns where each group represents a stretch of contiguous columns in the
alignment. We define a test set that consists of secondary structure elements
({\alpha}-helixes and {\beta}-strands) across more than 1,100 PFAM families.
Using these alignments to predict segments that are physically close in
structure, we show that our method substantially out-performs approaches that
aggregate the results of algorithms that operate on individual column pairs.
Our approach demonstrates that considering units of proteins beyond pairs of
columns can improve the power and utility of covariance algorithms.


title:
Interacting fermionic topological insulators/superconductors in three
  dimensions

abstract:
  Symmetry Protected Topological (SPT) phases are a minimal generalization of
the concept of topological insulators to interacting systems. In this paper we
describe the classification and properties of such phases for three
dimensional(3D) electronic systems with a number of different symmetries. For
symmetries representative of all classes in the famous 10-fold way of free
fermion topological insulators/superconductors, we determine the stability to
interactions. By combining with results on bosonic SPT phases we obtain a
classification of electronic 3D SPT phases for these symmetries. In cases with
a normal U(1) subgroup we show that this classification is complete. We
describe the non-trivial surface and bulk properties of these states. In
particular we discuss interesting correlated surface states that are not
captured in a free fermion description. We show that in many, but not all
cases, the surface can be gapped while preserving symmetry if it develops
intrinsic topological order.


title: The reflexive closure of the adjointable operators

abstract:
  Given a Hilbert module E over a C*-algebra A, we show that the collection of
all bounded A-module operators acting on E forms the reflexive closure for the
algebra of the adjointable operators. We also make an observation regarding the
representation theory of the left centralizer algebra of a C*-algebra and use
it to give an intuitive proof of a related result of H. Lin


title:
Monteiro spaces and rough sets determined by quasiorder relations:
  Models for Nelson algebras

abstract:
  Rough sets induced by quasiorders appear in several constructions using
binary relations in computer science. In this paper, a structural
characterisation of rough sets induced by quasiorders is given. These rough
sets form Nelson algebras defined on algebraic lattices. We prove that any
Nelson algebra can be represented as a subalgebra of an algebra defined on
rough sets induced by a suitable quasiorder. We also show that Monteiro spaces,
rough sets induced by quasiorders and Nelson algebras defined on $\rm
T_0$-spaces that are Alexandrov topologies can be considered as equivalent
structures, because they determine each other up to isomorphism.


title:
The non-universality of the low-mass end of the IMF is robust against
  the choice of SSP model

abstract:
  We perform a direct comparison of two state-of-the art single stellar
population (SSP) models that have been used to demonstrate the non-universality
of the low-mass end of the Initial Mass Function (IMF) slope. The two public
versions of the SSP models are restricted to either solar abundance patterns or
solar metallicity, too restrictive if one aims to disentangle elemental
enhancements, metallicity changes and IMF variations in massive early-type
galaxies (ETGs) with star formation histories different from the solar
neighborhood. We define response functions (to metallicity and
\alpha-abundance) to extend the parameter space of each set of models. We
compare these extended models with a sample of Sloan Digital Sky Survey (SDSS)
ETGs spectra with varying velocity dispersions. We measure equivalent widths of
optical IMF-sensitive stellar features to examine the effect of the underlying
model assumptions and ingredients, such as stellar libraries or isochrones, on
the inference of the IMF slope down to ~0.1 solar masses. We demonstrate that
the steepening of the low-mass end of the Initial Mass Function (IMF) based on
a non-degenerate set of spectroscopic optical indicators is robust against the
choice of the stellar population model. Although the models agree in a relative
sense (i.e. both imply more bottom-heavy IMFs for more massive systems), we
find non-negligible differences on the absolute values of the IMF slope
inferred at each velocity dispersion by using the two different models. In
particular, we find large inconsistency in the quantitative predictions of IMF
slope variations and abundance patterns when sodium lines are used. We
investigate the possible reasons for these inconsistencies.


title: Is the Universe Simpler than LCDM?

abstract:
  In the standard cosmological model, the Universe consists mainly of two
invisible substances: vacuum energy with constant mass-density
rho_v=\Lambda/(8pi G) (where Lambda is a `cosmological constant' originally
proposed by Einstein and G is Newton's gravitational constant) and cold dark
matter (CDM) with mass density that is currently rho_{DM,0}\sim 0.3 rho_v. This
`LCDM' model has the virtue of simplicity, enabling straightforward calculation
of the formation and evolution of cosmic structure against the backdrop of
cosmic expansion. Here we review apparent discrepancies with observations on
small galactic scales, which LCDM must attribute to complexity in the baryon
physics of galaxy formation. Yet galaxies exhibit structural scaling relations
that evoke simplicity, presenting a clear challenge for formation models. In
particular, tracers of gravitational potentials dominated by dark matter show a
correlation between orbital size, R, and velocity, V, that can be expressed
most simply as a characteristic acceleration, a_{DM}\sim 1 km^2 s^{-2} pc^{-1}
\approx 3 x 10^{-9} cm s^{-2} \approx 0.2c\sqrt{G rho_v}, perhaps motivating
efforts to find a link between localized and global manifestations of the
Universe's dark components.


title: Regularity of the Ito-Lyons map

abstract:
  We show in this note that the Ito-Lyons solution map associated to a rough
differential equation is Frechet differentiable when understood as a map
between some Banach spaces of controlled paths. This regularity result provides
an elementary approach to Taylor-like expansions of Inahama-Kawabi type for
solutions of rough differential equations depending on a small parameter, and
makes the construction of some natural dynamics on the path space over any
compact Riemannian manifold straightforward, giving back Driver's flow as a
particular case.


title: Internalization of extensional equality

abstract:
  We give a type system in which the universe of types is closed by reflection
into it of the logical relation defined externally by induction on the
structure of types. This contribution is placed in the context of the search
for a natural, syntactic construction of the extensional equality type (Tait
[1995], Altenkirch [1999], Coquand [2011], Licata and Harper [2012], Martin-Lof
[2013]). The system is presented as an extension of lambda-*, the terminal pure
type system in which the universe of all types is a type. The universe
inconsistency is then removed by the usual method of stratification into
levels. We give a set-theoretic model for the stratified system. We conjecture
that Strong Normalization holds as well.


title: Cosmological fluctuations of a random field and radiation fluid

abstract:
  A generalization of the random fluid hydrodynamic fluctuation theory due to
Landau and Lifshitz is applied to describe cosmological fluctuations in systems
with radiation and scalar fields. The viscous pressures, parametrized in terms
of the bulk and shear viscosity coefficients, and the respective random
fluctuations in the radiation fluid are combined with the stochastic and
dissipative scalar evolution equation. This results in a complete set of
equations describing the perturbations in both scalar and radiation fluids.
These derived equations are then studied, as an example, in the context of warm
inflation. Similar treatments can be done for other cosmological early universe
scenarios involving thermal or statistical fluctuations.


title:
Multi-indexed Extensions of Soliton Potential and Extended Integer
  Solitons of KdV Equation

abstract:
  We calculate infinite set of initial profiles of higher integer KdV solitons,
which are both exactly solvable for the Schrodinger equation and for the
Gel'fand-Levitan-Marchenko equation in the inverse scattering transform method
of KdV equation. The calculation of these higher integer soliton solutions is
based on the recently developed multi-indexed extensions of the reflectionless
soliton potential.


title:
An improved model of Charge Transfer Inefficiency and correction
  algorithm for the Hubble Space Telescope

abstract:
  Charge-Coupled Device (CCD) detectors, widely used to obtain digital imaging,
can be damaged by high energy radiation. Degraded images appear blurred,
because of an effect known as Charge Transfer Inefficiency (CTI), which trails
bright objects as the image is read out. It is often possible to correct most
of the trailing during post-processing, by moving flux back to where it
belongs. We compare several popular algorithms for this: quantifying the effect
of their physical assumptions and tradeoffs between speed and accuracy. We
combine their best elements to construct a more accurate model of damaged CCDs
in the Hubble Space Telescope's Advanced Camera for Surveys/Wide Field Channel,
and update it using data up to early 2013. Our algorithm now corrects 98% of
CTI trailing in science exposures, a substantial improvement over previous
work. Further progress will be fundamentally limited by the presence of read
noise. Read noise is added after charge transfer so does not get trailed - but
it is incorrectly untrailed during post-processing.


title:
Hygro-thermo-mechanical analysis of spalling in concrete walls at high
  temperatures as a moving boundary problem

abstract:
  A mathematical model allowing coupled hygro-thermo-mechanical analysis of
spalling in concrete walls at high temperatures by means of the moving boundary
problem is presented. A simplified mechanical approach to account for effects
of thermal stresses and pore pressure build-up on spalling is incorporated into
the model. The numerical algorithm based on finite element discretization in
space and the semi-implicit method for discretization in time is presented. The
validity of the developed model is carefully examined by a comparison between
experimental tests performed by Kalifa et al. (2000) and Mindeguia (2009) on
concrete prismatic specimens under unidirectional heating of temperature of 600
${\deg}$C and ISO 834 fire curve and the results obtained from the numerical
model.


title:
Ab initio lattice dynamical studies of silicon clathrate frameworks and
  their negative thermal expansion

abstract:
  The thermal and lattice dynamical properties of seven silicon clathrate
framework structures are investigated with ab initio density functional methods
(frameworks I, II, IV, V, VII, VIII, and H). The negative thermal expansion
(NTE) phenomenon is investigated by means of quasiharmonic approximation and
applying it to equal time displacement correlation functions. The thermal
properties of the studied clathrate frameworks, excluding the VII framework,
resemble those of the crystalline silicon diamond structure. The clathrate
framework VII was found to have anomalous NTE temperature range up to 300 K and
it is suitable for further studies of the mechanisms of NTE. Investigation of
the displacement correlation functions revealed that in NTE, the volume
derivatives of the mean square displacements and mean square relative
displacements of atoms behave similarly to the vibrational entropy volume
derivatives and consequently to the coefficients of thermal expansion as a
function of temperature. All studied clathrate frameworks, excluding the VII
framework, possess a phonon band gap or even two in the case of the framework
V.


title:
Monte Carlo Computation of the Vassiliev knot invariant of degree 2 in
  the integral representation

abstract:
  In mathematics there is a wide class of knot invariants that may be expressed
in the form of multiple line integrals computed along the trajectory C
describing the spatial conformation of the knot. In this work it is addressed
the problem of evaluating invariants of this kind in the case in which the knot
is discrete, i.e. its trajectory is constructed by joining together a set of
segments of constant length. Such discrete knots appear almost everywhere in
numerical simulations of systems containing one dimensional ring-shaped
objects. Examples are polymers, the vortex lines in fluids and superfluids like
helium and other quantum liquids. Formally, the trajectory of a discrete knot
is a piecewise smooth curve characterized by sharp corners at the joints
between contiguous segments. The presence of these corners spoils the
topological invariance of the knot invariants considered here and prevents the
correct evaluation of their values. To solve this problem, a smoothing
procedure is presented, which eliminates the sharp corners and transforms the
original path C into a curve that is everywhere differentiable. The procedure
is quite general and can be applied to any discrete knot defined off or on
lattice. This smoothing algorithm is applied to the computation of the
Vassiliev knot invariant of degree 2 denoted here with the symbol r(C). This is
the simplest knot invariant that admits a definition in terms of multiple line
integrals. For a fast derivation of r(C), it is used a Monte Carlo integration
technique. It is shown that, after the smoothing, the values of r(C) may be
evaluated with an arbitrary precision. Several algorithms for the fast
computation of the Vassiliev knot invariant of degree 2 are provided.


title: Two-valued states on Baer $^*$-semigroups

abstract:
  In this paper we develop an algebraic framework that allows us to extend
families of two-valued states on orthomodular lattices to Baer $^*$-semigroups.
We apply this general approach to study the full class of two-valued states and
the subclass of Jauch-Piron two-valued states on Baer $^*$-semigroups.


title: Algebraisable versions of predicate topological logic

abstract:
  Motivated by questions like: which spatial structures may be characterized by
means of modal logic, what is the logic of space, how to encode in modal logic
different geometric relations, topological logic provides a framework for
studying the confluence of the topological semantics for $\sf S4$ modalities,
based on topological spaces rather than Kripke frames.
  Following research initiated by Sgro, and further pursued algebraically by
Georgescu, we prove an interpolation theorem and an omitting types theorem for
various extensions of predicate topological logic and Chang's modal logic. Our
proof is algebraic addressing expansions of cylindric algebras using interior
operators and boxes, respectively. Then we proceed like is done in abstract
algebraic logic by studing algebraisable extensions of both logics; obtaining a
plethora of results on the amalgamation property for various subclasses of
their algebraic counterparts, which are varieties. Notions like atom-canonicity
and complete representations are approached for finite dimensional topological
cylindric algebras. The logical consequences of our algebraic results are
carefully worked out for infinitary extensions of Chang's predicate modal logic
and finite versions thereof, by restricting to $n$ variables, $n$ finite,
viewed as a propositional multi-dimensional modal logic, and $n$ products of
bimodal whose frames are of the form $(U, U\times U, R)$ where $R$ is a
pre-order, endowed with diagonal constants.


title: Band offsets in heterojunctions between cubic perovskite oxides

abstract:
  The band offsets for nine heterojunctions between titanates, zirconates, and
niobates with the cubic perovskite structure were calculated from first
principles. The effect of strain in contacting oxides on their energy
structure, many-body corrections to the position of the band edges (calculated
in the GW approximation), and the splitting of the conduction band resulting
from spin-orbit interaction were consistently taken into account. It was shown
that the neglect of the many-body effects can lead to errors in determination
of the band offsets up to 0.36 eV. The failure of the transitivity rule, which
is often used to determine the band offsets in heterojunctions, was
demonstrated and its cause was explained.


title: Effective Slot Filling Based on Shallow Distant Supervision Methods

abstract:
  Spoken Language Systems at Saarland University (LSV) participated this year
with 5 runs at the TAC KBP English slot filling track. Effective algorithms for
all parts of the pipeline, from document retrieval to relation prediction and
response post-processing, are bundled in a modular end-to-end relation
extraction system called RelationFactory. The main run solely focuses on
shallow techniques and achieved significant improvements over LSV's last year's
system, while using the same training data and patterns. Improvements mainly
have been obtained by a feature representation focusing on surface skip n-grams
and improved scoring for extracted distant supervision patterns. Important
factors for effective extraction are the training and tuning scheme for distant
supervision classifiers, and the query expansion by a translation model based
on Wikipedia links. In the TAC KBP 2013 English Slotfilling evaluation, the
submitted main run of the LSV RelationFactory system achieved the top-ranked
F1-score of 37.3%.


title: Some families of graphs whose domination polynomials are unimodal

abstract:
  Let $G$ be a simple graph of order $n$. The domination polynomial of $G$ is
the polynomial $D(G, x)=\sum_{i=\gamma(G)}^{n} d(G,i) x^{i}$, where $d(G,i)$ is
the number of dominating sets of $G$ of size $i$ and $\gamma(G)$ is the
domination number of $G$. It is conjectured that the domination polynomial of
any graph is unimodal. In this paper we present some families of graphs whose
domination polynomials are unimodal.


title: Patching and Quillen K-Theory

abstract:
  This paper provides an isomorphism $K_n (\mathscr{A}) \cong K_n
(\mathscr{A}_1) \times_{K_n(\mathscr{A}_0)} K_n(\mathscr{A}_2)$ of $K$-groups,
i.e., an exact sequence $0 \to K_n(\mathscr{A}) \to K_n(\mathscr{A}_1)\times
K_n(\mathscr{A}_2) \to K_n(\mathscr{A}_0)$ corresponding to a 2-fiber product
of abelian categories, taken with respect to exact functors. Using recent
patching results of D. Harbater, J. Hartmann and D. Krashen, given fields $F_1,
F_2 \leq F_0$ and $F= F_1 \cap F_2$ which satisfy a simple matrix factorization
criterion, our isomorphism relates the $K$-groups of the fields $F$ and $F_i$
($i$ = 0, 1, 2). In particular, we establish a local-global principle for
$K$-theory of function fields of curves defined over a complete discretely
valued field.


title: Distinguishing topologically and smoothly doubly slice knots

abstract:
  We construct an infinite family of smoothly slice knots that we prove are
topologically doubly slice. Using the correction terms coming from Heegaard
Floer homology, we show that none of these knots is smoothly doubly slice. We
use these knots to show that the subgroup of the double concordance group
consisting of smoothly slice, topologically doubly slice knots is infinitely
generated. As a corollary, we produce an infinite collection of rational
homology 3-spheres that embed in $S^4$ topologically, but not smoothly.


title: Monojets and mono-photons from light higgsino pair production at LHC14

abstract:
  Naturalness arguments imply the existence of higgsinos lighter than 200-300
GeV. However, because these higgsinos are nearly mass degenerate, they release
very little visible energy in their decays, and signals from electroweak
higgsino pair production typically remain buried under Standard Model
backgrounds. Moreover, gluinos, squarks and winos may plausibly lie beyond the
reach of the LHC14, so that signals from naturalness-inspired supersymmetric
models may well remain hidden via conventional searches. We examine instead
prospects for detecting higgsino pair production via monojets or mono-photons
from initial state radiation. We find typical signal-to-background rates at
best at the 1 % level, leading to rather pessimistic conclusions regarding
detectability via these channels.


title:
Proceedings of the 3rd MANIAC Challenge, Berlin, Germany, July 27 - 28,
  2013

abstract:
  This is the Proceedings of the 3rd MANIAC Challenge, which was held in
Berlin, Germany, July 27 - 28, 2013.


title:
Novel Synchronization of Pulse-Coupled Oscillators on Time-Varying
  Networks

abstract:
  In this article I investigate the novel synchronization behaviors of evolving
pulse-coupled oscillator networks. Unlike previous models, the time-varying
mechanism is inspired by neural network development, where seldom used links
die out while heavily used ones get strengthened. Even small network with
all-to-all connected topology can have exotic dynamics under this circumstance.
The oscillators can coevolve with the network, and finally form a
co-synchronized pair. Or if we only allow a fraction of oscillators to send
pulses every time, the oscillators can synchronize with the network remain
chaotic.


title:
The causal meaning of genomic predictors and how it affects the
  construction and comparison of genome-enabled selection models

abstract:
  The additive genetic effect is arguably the most important quantity inferred
in animal and plant breeding analyses. The term effect indicates that it
represents causal information, which is different from standard statistical
concepts as regression coefficient and association. The process of inferring
causal information is also different from standard statistical learning, as the
former requires causal (i.e. non-statistical) assumptions and involves extra
complexities. Remarkably, the task of inferring genetic effects is largely seen
as a standard regression/prediction problem, contradicting its label. This
widely accepted analysis approach is by itself insufficient for causal
learning, suggesting that causality is not the point for selection. Given this
incongruence, it is important to verify if genomic predictors need to represent
causal effects to be relevant for selection decisions, especially because
applying regression studies to answer causal questions may lead to wrong
conclusions. The answer to this question defines if genomic selection models
should be constructed aiming maximum genomic predictive ability or aiming
identifiability of genetic causal effects. Here, we demonstrate that selection
relies on a causal effect from genotype to phenotype, and that genomic
predictors are only useful for selection if they distinguish such effect from
other sources of association. Conversely, genomic predictors capturing
non-causal signals provide information that is less relevant for selection
regardless of the resulting predictive ability. Focusing on covariate choice
decision, simulated examples are used to show that predictive ability, which is
the criterion normally used to compare models, may not indicate the quality of
genomic predictors for selection. Additionally, we propose using alternative
criteria to construct models aiming for the identification of the genetic
causal effects.


title: On integrable conservation laws

abstract:
  We study normal forms of scalar integrable dispersive (non necessarily
Hamiltonian) conservation laws via the Dubrovin-Zhang perturbative scheme. Our
computations support the conjecture that such normal forms are parametrised by
infinitely many arbitrary functions that can be identified with the
coefficients of the quasilinear part of the equation. More in general, we
conjecture that two scalar integrable evolutionary PDEs having the same
quasilinear part are Miura equivalent. This conjecture is also consistent with
the tensorial behaviour of these coefficients under general Miura
transformations.


title: SLE and Virasoro representations: Fusion

abstract:
  We continue the study of null-vector equations in relation with partition
functions of (systems of) Schramm-Loewner Evolutions (SLEs) by considering the
question of fusion. Starting from $n$ commuting SLEs seeded at distinct points,
the partition function satisfies $n$ null-vector equations (at level 2). We
show how to obtain higher level null-vector equations by coalescing the seeds
one by one. As an example, we extend Schramm's formula (for the position of a
marked bulk point relatively to a chordal SLE trace) to an arbitrary number of
SLE strands.
  The argument combines input from representation theory - the study of Verma
modules for the Virasoro algebra - with regularity estimates, themselves based
on hypoellipticity and stochastic flow arguments.


title: Field Effect Transistor Nanosensor for Breast Cancer Diagnostics

abstract:
  Silicon nanochannel field effect transistor (FET) biosensors are one of the
most promising technologies in the development of highly sensitive and
label-free analyte detection for cancer diagnostics. With their exceptional
electrical properties and small dimensions, silicon nanochannels are ideally
suited for extraordinarily high sensitivity. In fact, the high
surface-to-volume ratios of these systems make single molecule detection
possible. Further, FET biosensors offer the benefits of high speed, low cost,
and high yield manufacturing, without sacrificing the sensitivity typical for
traditional optical methods in diagnostics. Top down manufacturing methods
leverage advantages in Complementary Metal Oxide Semiconductor (CMOS)
technologies, making richly multiplexed sensor arrays a reality. Here, we
discuss the fabrication and use of silicon nanochannel FET devices as
biosensors for breast cancer diagnosis and monitoring.


title: Correlation structure of time-changed Pearson diffusions

abstract:
  The stochastic solution to diffusion equations with polynomial coefficients
is called a Pearson diffusion. If the time derivative is replaced by a
distributed fractional derivative, the stochastic solution is called a
fractional Pearson diffusion. This paper develops a formula for the covariance
function of a fractional Pearson diffusion in steady state, in terms of
generalized Mittag-Leffler functions. That formula shows that fractional
Pearson diffusions are long-range dependent, with a correlation that falls off
like a power law, whose exponent equals the smallest order of the distributed
fractional derivative.


title: The Asymptotics of Large Constrained Graphs

abstract:
  We show, through local estimates and simulation, that if one constrains
simple graphs by their densities $\varepsilon$ of edges and $\tau$ of
triangles, then asymptotically (in the number of vertices) for over $95\%$ of
the possible range of those densities there is a well-defined typical graph,
and it has a very simple structure: the vertices are decomposed into two
subsets $V_1$ and $V_2$ of fixed relative size $c$ and $1-c$, and there are
well-defined probabilities of edges, $g_{jk}$, between $v_j\in V_j$, and
$v_k\in V_k$. Furthermore the four parameters $c, g_{11}, g_{22}$ and $g_{12}$
are smooth functions of $(\varepsilon,\tau)$ except at two smooth `phase
transition' curves.


title: Using Delta-Sigma Modulators in Visible Light OFDM Systems

abstract:
  Visible light communications (VLC) are motivated by the radio-frequency (RF)
spectrum crunch and fast-growing solid-state lighting technology. VLC relies on
white light emitting diodes (LEDs) to provide communication and illumination
simultaneously. Simple two-level on-off keying (OOK) and pulse-position
modulation (PPM) are supported in IEEE standard due to their compatibility with
existing constant current LED drivers, but their low spectral efficiency have
limited the achievable data rates of VLC. Orthogonal frequency division
multiplexing (OFDM) has been applied to VLC due to its high spectral efficiency
and ability to combat inter-symbol-interference (ISI). However, VLC-OFDM
inherits the disadvantage of high peak-to-average power ratio (PAPR) from
RF-OFDM. Besides, the continuous magnitude of OFDM signals requires complicated
mixed-signal digital-to-analog converter (DAC) and modification of LED drivers.
We propose the use of delta-sigma modulators in visible light OFDM systems to
convert continuous magnitude OFDM symbols into LED driver signals. The proposed
system has the communication theory advantages of OFDM along with the practical
analog and optical advantages of simple two level driver signals. Simulation
results are provided to illustrate the proposed system.


title: Logical systems II: Free semantics

abstract:
  This paper is a sequel to "Logical systems I: Lambda calculi through
discreteness". It provides a general 2-categorical setting for extensional
calculi and shows how intensional and extensional calculi can be related in
logical systems. We define Yoneda triangles as relativisations of internal
adjunctions, and use them to characterise universes that admit a notion of
convolution. We show that such universes induce semantics for lambda calculi.
We prove that a construction analogical to enriched Day convolution works for
categories internal to a locally cartesian closed category with finite
colimits.


title: Gupta-Bleuler Photon Quantization in the SME

abstract:
  Photon quantization is implemented in the standard model extension (SME)
using the Gupta-Bleuler method and BRST concepts. The quantization prescription
applies to both the birefringent and non-birefringent CPT-even couplings. A
curious incompatibility is found between the presence of the Lorentz-violating
terms and the existence of a nontrivial conjugate momentum $\Pi^0$ yielding
problems with covariant quantization procedure. Introduction of a mass
regulator term can avoid the vanishing of $\Pi^0$ and allows for the
implementation of a covariant quantization procedure. Field-theoretic
calculations involving the SME photons can then be performed using the mass
regulator, similar to the conventional procedure used in electrodynamics for
infrared-divergence regulation.


title:
Towards Breaking the Curse of Dimensionality for High-Dimensional
  Privacy: An Extended Version

abstract:
  The curse of dimensionality has remained a challenge for a wide variety of
algorithms in data mining, clustering, classification and privacy. Recently, it
was shown that an increasing dimensionality makes the data resistant to
effective privacy. The theoretical results seem to suggest that the
dimensionality curse is a fundamental barrier to privacy preservation. However,
in practice, we show that some of the common properties of real data can be
leveraged in order to greatly ameliorate the negative effects of the curse of
dimensionality. In real data sets, many dimensions contain high levels of
inter-attribute correlations. Such correlations enable the use of a process
known as vertical fragmentation in order to decompose the data into vertical
subsets of smaller dimensionality. An information-theoretic criterion of mutual
information is used in the vertical decomposition process. This allows the use
of an anonymization process, which is based on combining results from multiple
independent fragments. We present a general approach which can be applied to
the k-anonymity, l-diversity, and t-closeness models. In the presence of
inter-attribute correlations, such an approach continues to be much more robust
in higher dimensionality, without losing accuracy. We present experimental
results illustrating the effectiveness of the approach. This approach is
resilient enough to prevent identity, attribute, and membership disclosure
attack.


title: Propagation of Reactions in Inhomogeneous Media

abstract:
  Consider reaction-diffusion equation $u_t=\Delta u + f(x,u)$ with
$x\in\mathbb{R}^d$ and general inhomogeneous ignition reaction $f\ge 0$
vanishing at $u=0,1$. Typical solutions $0\le u\le 1$ transition from $0$ to
$1$ as time progresses, and we study them in the region where this transition
occurs. Under fairly general qualitative hypotheses on $f$ we show that in
dimensions $d\le 3$, the Hausdorff distance of the super-level sets
$\{u\ge\epsilon\}$ and $\{u\ge 1-\epsilon\}$ remains uniformly bounded in time
for each $\epsilon\in(0,1)$. Thus, $u$ remains uniformly in time close to the
characteristic function of $\{u\ge\tfrac 12\}$ in the sense of Hausdorff
distance of super-level sets. We also show that $\{u\ge\tfrac 12\}$ expands
with average speed (over any long enough time interval) between the two
spreading speeds corresponding to any $x$-independent lower and upper bounds on
$f$. On the other hand, these results turn out to be false in dimensions $d\ge
4$, at least without further quantitative hypotheses on $f$. The proof for
$d\le 3$ is based on showing that as the solution propagates, small values of
$u$ cannot escape far ahead of values close to 1. The proof for $d\ge 4$
involves construction of a counter-example for which this fails.
  Such results were before known for $d=1$ but are new for general non-periodic
media in dimensions $d\ge 2$ (some are also new for homogeneous and periodic
media). They extend in a somewhat weaker sense to monostable, bistable, and
mixed reaction types, as well as to transitions between general equilibria
$u^-<u^+$ of the PDE, and to solutions not necessarily satisfying $u^-\le u\le
u^+$.


title: Order by Disorder Spin Wave Gap in the XY Pyrochlore Magnet Er2Ti2O7

abstract:
  The recent determination of a robust spin Hamiltonian for the
anti-ferromagnetic XY pyrochlore Er2Ti2O7 reveals a most convincing case of the
"order by quantum disorder" (ObQD) mechanism for ground state selection. This
mechanism relies on quantum fluctuations to remove an accidental symmetry of
the magnetic ground state, and selects a particular ordered spin structure
below T_N=1.2K. The removal of the continuous degeneracy results in an energy
gap in the spectrum of spin wave excitations, long wavelength pseudo-Goldstone
modes. We have measured the ObQD spin wave gap at a zone center in Er2Ti2O7,
using low incident energy neutrons and the time-of-flight inelastic scattering
method. We report a gap of Delta =0.053 +/- 0.006 meV, which is consistent with
upper bounds placed on it from heat capacity measurements and roughly
consistent with theoretical estimate of ~ 0.02 meV, further validating the spin
Hamiltonian that led to that prediction. The gap is observed to vary with
square of the order parameter, and goes to zero for T ~ T_N.


title: Multilevel Richardson-Romberg extrapolation

abstract:
  We propose and analyze a Multilevel Richardson-Romberg (MLRR) estimator which
combines the higher order bias cancellation of the Multistep Richardson-Romberg
method introduced in [Pa07] and the variance control resulting from the
stratification introduced in the Multilevel Monte Carlo (MLMC) method (see
[Hei01, Gi08]). Thus, in standard frameworks like discretization schemes of
diffusion processes, the root mean squared error (RMSE) $\varepsilon > 0$ can
be achieved with our MLRR estimator with a global complexity of
$\varepsilon^{-2} \log(1/\varepsilon)$ instead of $\varepsilon^{-2}
(\log(1/\varepsilon))^2$ with the standard MLMC method, at least when the weak
error $\mathbf{E}[Y_h]-\mathbf{E}[Y_0]$ of the biased implemented estimator
$Y_h$ can be expanded at any order in $h$ and $\|Y_h - Y_0\|_2 =
O(h^{\frac{1}{2}})$. The MLRR estimator is then halfway between a regular MLMC
and a virtual unbiased Monte Carlo. When the strong error $\|Y_h - Y_0\|_2 =
O(h^{\frac{\beta}{2}})$, $\beta < 1$, the gain of MLRR over MLMC becomes even
more striking. We carry out numerical simulations to compare these estimators
in two settings: vanilla and path-dependent option pricing by Monte Carlo
simulation and the less classical Nested Monte Carlo simulation.


title:
High-performance solution of the transport problem in a graphene
  armchair structure with a generic potential

abstract:
  We propose an efficient numerical method to study the transport properties of
armchair graphene ribbons in the presence of a generic external potential. The
method is based on a continuum envelope-function description with physical
boundary conditions. The envelope functions are computed in the reciprocal
space, and the transmission is then obtained with a recursive scattering matrix
approach. This allows a significant reduction of the computational time with
respect to finite difference simulations.


title:
Local regularity properties of almost- and quasiminimal sets with a
  sliding boundary condition

abstract:
  We study the boundary regularity of almost minimal and quasiminimal sets that
satisfy sliding boundary conditions. The competitors of a set $E$ are defined
as $F = \varphi_1(E)$, where $\{ \varphi_t \}$ is a one parameter family of
continuous mappings defined on $E$, and that preserve a given collection of
boundary pieces. We generalize known interior regularity results, and in
particular we show that the quasiminimal sets are locally Ahlfors-regular,
rectifiable, and some times uniformly rectifiable, that our classes are stable
under limits, and that for almost minimal sets the density of Hausdorff measure
in balls centered on the boundary is almost nondecreasing.


title:
Holographic estimation of multiplicity and membranes collision in
  modified spaces ${AdS}_5$

abstract:
  The quark-gluon plasma formed as a result of heavy-ion collisions is
currently investigated actively both theoretically and experimentally.
According to the holographic approach, forming a quark-gluon plasma in the
four-dimensional world is associated with creating black holes in a
five-dimensional anti-de Sitter space. The multiplicity of particles produced
in heavy-ion collisions is then determined by the entropy of the
five-dimensional black hole, which is estimated by the area of the trapped
surface. To fit the experimental data for multiplicity Kiritsis and Taliotis
have proposed to consider black holes formation in modified ${AdS}_5$ spaces
with different $b$-factors. In this paper we consider the formation of black
holes under collision of membranes in modified ${AdS}_5$ spaces with
$b$-factors. Following the previous proposals we consider the power-law and
exponential $b$-factors, as well as mixed types of $b$-factors. We study
dynamics of the change of the trapped surface area depending on the energy for
each investigated space. We find that the power-law and mixed factors fit
better to the experimental date.


title: Determination of Forces from a Potential in Molecular Dynamics

abstract:
  In Molecular Dynamics (MD), the forces applied to atoms derive from
potentials which describe the energy of bonds, valence angles, torsion angles,
and Lennard-Jones interactions of which molecules are made. These de finitions
are classic; on the contrary, their implementation in a MD system which
respects local equilibrium of mechanical conditions is usually not described.
The precise derivation of the forces from the potential and the proof that
their application preserves energy is the object of this note. This work is
part of the building of a multi-scale MD system, presently under development.


title:
Influence of a spatial structure on the long time behavior of a
  competitive Lotka-Volterra type system

abstract:
  To describe population dynamics, it is crucial to take into account jointly
evolution mechanisms and spatial motion. However, the models which include
these both aspects, are not still well-understood. Can we extend the existing
results on type structured populations, to models of populations structured by
type and space, considering diffusion and nonlocal competition between
individuals? We study a nonlocal competitive Lotka-Volterra type system,
describing a spatially structured population which can be either monomorphic or
dimorphic. Considering spatial diffusion, intrinsic death and birth rates,
together with death rates due to intraspecific and interspecific competition
between the individuals, leading to some integral terms, we analyze the long
time behavior of the solutions. We first prove existence of steady states and
next determine the long time limits, depending on the competition rates and the
principal eigenvalues of some operators, corresponding somehow to the strength
of traits. Numerical computations illustrate that the introduction of a new
mutant population can lead to the long time evolution of the spatial niche.


title:
An Adaptive Shifted Power Method for Computing Generalized Tensor
  Eigenpairs

abstract:
  Several tensor eigenpair definitions have been put forth in the past decade,
but these can all be unified under generalized tensor eigenpair framework,
introduced by Chang, Pearson, and Zhang (2009). Given mth-order, n-dimensional
real-valued symmetric tensors A and B, the goal is to find $\lambda \in R$ and
$x \in R^n$, $x \neq 0$, such that $Ax^{m-1} = \lambda Bx^{m-1}$. Different
choices for B yield different versions of the tensor eigenvalue problem. We
present our generalized eigenproblem adaptive power method (GEAP) method for
solving the problem, which is an extension of the shifted symmetric
higher-order power method (SS-HOPM) for finding Z-eigenpairs. A major drawback
of SS-HOPM was that its performance depended in choosing an appropriate shift,
but our GEAP method also includes an adaptive method for choosing the shift
automatically.


title:
Classical and quantum shortcuts to adiabaticity for scale-invariant
  driving

abstract:
  A shortcut to adiabaticity is a driving protocol that reproduces in a short
time the same final state that would result from an adiabatic, infinitely slow
process. A powerful technique to engineer such shortcuts relies on the use of
auxiliary counterdiabatic fields. Determining the explicit form of the required
fields has generally proven to be complicated. We present explicit
counterdiabatic driving protocols for scale-invariant dynamical processes,
which describe for instance expansion and transport. To this end, we use the
formalism of generating functions, and unify previous approaches independently
developed in classical and quantum studies. The resulting framework is applied
to the design of shortcuts to adiabaticity for a large class of classical and
quantum, single-particle, non-linear, and many-body systems.


title: The flush statistic on semistandard Young tableaux

abstract:
  In this note, a statistic on Young tableaux is defined which encodes data
needed for the Casselman-Shalika formula.


title: Vanishing of the first continuous L^2-cohomology for II_1 factors

abstract:
  We prove that the continuous version of the Connes-Shlyakhtenko first
L^2-cohomology for II_1 factors, as proposed by A. Thom in [Th06], always
vanishes.


title:
Bethe Ansatz equations for the classical $A_n^{(1)}$ affine Toda field
  theories

abstract:
  We establish a correspondence between classical $A_n^{(1)}$ affine Toda field
theories and $A_n$ Bethe Ansatz systems. We show that the connection
coefficients relating specific solutions of the associated classical linear
problem satisfy functional relations of the type that appear in the context of
the massive quantum integrable model.


title: Anisotropic Hydrodynamics: Motivation and Methodology

abstract:
  In this proceedings contribution I review recent progress in our
understanding of the bulk dynamics of relativistic systems that possess
potentially large local rest frame momentum-space anisotropies. In order to
deal with these momentum-space anisotropies, a reorganization of relativistic
viscous hydrodynamics can been made around an anisotropic background, and the
resulting dynamical framework has been dubbed "anisotropic hydrodynamics." I
also discuss expectations for the degree of momentum-space anisotropy of the
quark gluon plasma generated in relativistic heavy ion collisions at RHIC and
LHC from second-order viscous hydrodynamics, strong-coupling approaches, and
weak-coupling approaches.


title: Horizon thermodynamics and spacetime mappings

abstract:
  When black holes are dynamical, event horizons are replaced by apparent and
trapping horizons. Conformal and Kerr-Schild transformations are widely used in
relation with dynamical black holes and we study the behaviour under such
transformations of quantities related to the thermodynamics of these horizons,
such as the Misner-Sharp-Hernandez mass (internal energy), the Kodama vector,
surface gravity, and temperature. The transformation properties are not those
expected on the basis of naive arguments.


title: Bangla Text Recognition from Video Sequence: A New Focus

abstract:
  Extraction and recognition of Bangla text from video frame images is
challenging due to complex color background, low-resolution etc. In this paper,
we propose an algorithm for extraction and recognition of Bangla text form such
video frames with complex background. Here, a two-step approach has been
proposed. First, the text line is segmented into words using information based
on line contours. First order gradient value of the text blocks are used to
find the word gap. Next, a local binarization technique is applied on each word
and text line is reconstructed using those words. Secondly, this binarized text
block is sent to OCR for recognition purpose.


title: DASS: Distributed Adaptive Sparse Sensing

abstract:
  Wireless sensor networks are often designed to perform two tasks: sensing a
physical field and transmitting the data to end-users. A crucial aspect of the
design of a WSN is the minimization of the overall energy consumption. Previous
researchers aim at optimizing the energy spent for the communication, while
mostly ignoring the energy cost due to sensing. Recently, it has been shown
that considering the sensing energy cost can be beneficial for further
improving the overall energy efficiency. More precisely, sparse sensing
techniques were proposed to reduce the amount of collected samples and recover
the missing data by using data statistics. While the majority of these
techniques use fixed or random sampling patterns, we propose to adaptively
learn the signal model from the measurements and use the model to schedule when
and where to sample the physical field. The proposed method requires minimal
on-board computation, no inter-node communications and still achieves appealing
reconstruction performance. With experiments on real-world datasets, we
demonstrate significant improvements over both traditional sensing schemes and
the state-of-the-art sparse sensing schemes, particularly when the measured
data is characterized by a strong intra-sensor (temporal) or inter-sensors
(spatial) correlation.


title: Gluon Propagator in Fractional Analytic Perturbation Theory

abstract:
  We consider the gluon propagator in the Landau gauge at low spacelike momenta
and with the dressing function $Z(Q^2)$ at the two-loop order. We incorporate
the nonperturbative effects by making the (noninteger) powers of the QCD
coupling in the dressing function $Z(Q^2)$ analytic (holomorphic) via the
Fractional Analytic Perturbation Theory (FAPT) model, and simultaneously
introducing the gluon dynamical mass in the propagator as motivated by the
previous analyses of the Dyson-Schwinger equations. The obtained propagator has
behavior compatible with the unquenched lattice data ($N_f=2+1$) at low
spacelike momenta $0.4 \ {\rm GeV} < Q \lesssim 10$ GeV. We conclude that the
removal of the unphysical Landau singularities of the powers of the coupling
via the (F)APT prescription, in conjunction with the introduction of the
dynamical mass $M \approx 0.62$ GeV of the gluon, leads to an acceptable
behavior of the propagator in the infrared regime.


title: A WISE measurement of the ISW effect

abstract:
  The Integrated Sachs-Wolfe effect (ISW) measures the decay of the
gravitational potential due to cosmic acceleration and is thus a direct probe
of Dark Energy. In some of the earlier studies, the amplitude of the ISW effect
was found to be in tension with the predictions of the standard $\Lambda$CDM
model. We measure the cross-power of galaxies and AGN from the WISE mission
with CMB temperature data from WMAP9 in order to provide an independent
measurement of the ISW amplitude. Cross-correlations with the recently released
Planck lensing potential maps are used to calibrate the bias and contamination
fraction of the sources, thus avoiding systematic effects that could be present
when using auto-spectra to measure bias. We find an amplitude of the
cross-power of $\mathcal{A} = 1.24\pm 0.47$ from the galaxies and $\mathcal{A}
= 0.88 \pm 0.74$ from the AGN, fully consistent with the $\Lambda$CDM
prediction of $\mathcal{A} =1$. The ISW measurement signal-to-noise ratio is
2.7 and 1.2 respectively, giving a combined significance close to $3 \sigma$.
Comparing the amplitudes of the galaxy and AGN cross-correlations, which arise
from different redshifts, we find no evidence for redshift evolution in Dark
Energy properties, consistent with a Cosmological Constant.


title: WISE Y Dwarfs As Probes of the Brown Dwarf-Exoplanet Connection

abstract:
  We have determined astrometric positions for 15 WISE-discovered late-type
brown dwarfs (6 T8-9 and 9 Y dwarfs) using the Keck II telescope, the Spitzer
Space Telescope, and the Hubble Space Telescope. Combining data from 8 to 20
epochs we derive parallactic and proper motions for these objects which put the
majority within 15 parsecs. For ages greater than a few Gyr, as suggested from
kinematic considerations, we find masses of 10-30 M$_{Jup}$ based on standard
models for the evolution of low mass objects with a range of mass estimates for
individual objects depending on the model in question. Three of the coolest
objects have effective temperatures $\sim$ 350 K and inferred masses of 10-15
M$_{Jup}$. Our parallactic distances confirm earlier photometric estimates
(Kirkpatrick et al. 2012) and direct measurements (Marsh et al. 2013, Beichman
et al. 2013, Dupuy and Krauss 2013) and suggest that the number of objects with
masses below about 15 M$_{Jup}$ must be flat or declining relative to higher
mass objects. The masses of the coldest Y dwarfs may be similar to those
inferred for recently imaged planet-mass companions to nearby young stars.
Objects in this mass range, which appear to be rare in both the interstellar
and proto-planetary environments, may both have formed via gravitational
fragmentation: the brown dwarfs in interstellar clouds and companion objects in
a protoplanetary disk. In both cases, however, the fact that objects in this
mass range are relatively infrequent, suggests that this mechanism must be
inefficient in both environments.


title:
OGLE-LMC-ECL-11893: The discovery of a long-period eclipsing binary with
  a circumstellar disk

abstract:
  We report the serendipitous discovery of a disk-eclipse system
OGLE-LMC-ECL-11893. The eclipse occurs with a period of 468 days, a duration of
about 15 days and a deep (up to \Delta I ~1.5), peculiar and asymmetric
profile. A possible origin of such an eclipse profile involves a circumstellar
disk. The presence of the disk is confirmed by the H-alpha line profile from
the follow-up spectroscopic observations, and the star is identified as Be/Ae
type. Unlike the previously known disk-eclipse candidates (Epsilon Aurigae, EE
Cephei, OGLE-LMC-ECL-17782, KH 15D), the eclipses of OGLE-LMC-ECL-11893 retain
the same shape throughout the span of ~17 years (13 orbital periods),
indicating no measurable orbital precession of the disk.


title: Electromigration of bivalent functional groups on graphene

abstract:
  Chemical functionalization of graphene holds promise for various applications
ranging from nanoelectronics to catalysis, drug delivery, and nano-assembly. In
many of these applications it is critical to assess the rates of
electromigration - directed motion of adsorbates along the surface of
current-carrying graphene due to the electron wind force. In this paper, we
develop an accurate analytical theory of electromigration of bivalent
functional groups (epoxide, amine) on graphene. Specifically, we carefully
analyze various factors contributing to the electron wind force, such as
lattice effects and strong scattering beyond Born approximation, and derive a
simple analytical expression for this force. Further, we perform accurate
electronic structure theory calculations to parameterize the obtained
analytical expression. The obtained results can be generalized to different
functional groups and adsorbates, e.g., alkali atoms on graphene.


title: Free boundary conditions and the AdS$_3$/CFT$_2$ correspondence

abstract:
  We show that the recently proposed free boundary conditions for AdS$_3$ are
dual to two-dimensional quantum gravity in certain fixed gauges. In particular,
we note that an appropriate identification of the generator of Virasoro
transformations leads to a vanishing total central charge in agreement with the
theory at the boundary. We argue that this identification is necessary to match
the bulk and boundary generators of Virasoro transformations and for
consistency with the constraint equations.


title: Enhanced Stopping of Macro-Particles in Particle-in-Cell Simulations

abstract:
  We derive an equation for energy transfer from relativistic charged particles
to a cold background plasma appropriate for finite-size particles that are used
in particle-in-cell simulation codes. Expressions for one-, two-, and
three-dimensional particles are presented, with special attention given to the
two-dimensional case. This energy transfer is due to the electric field of the
wake set up in the background plasma by the relativistic particle. The enhanced
stopping is dependent on the $q^2/m$, where $q$ is the charge and $m$ is the
mass of the relativistic particle, and therefore simulation macro-particles
with large charge but identical $q/m$ will stop more rapidly. The stopping
power also depends on the effective particle shape of the macro-particle. These
conclusions are verified in particle-in-cell simulations. We present 2D
simulations of test particles, relaxation of high-energy tails, and integrated
fast ignition simulations showing that the enhanced drag on macro-particles may
adversely affect the results of these simulations in a wide range of
high-energy density plasma scenarios. We also describe a particle splitting
algorithm which can potentially overcome this problem and show its effect in
controlling the stopping of macro-particles.


title:
Thermoelectric properties of chalcopyrite type CuGaTe$_2$ and
  chalcostibite CuSbS$_2$

abstract:
  Electronic and transport properties of CuGaTe$_2$, a hole-doped ternary
copper based chalcopyrite type semiconductor, are studied using calculations
within the Density Functional Theory and solving the Boltzmann transport
equation within the constant relaxation time approximation. The electronic
bandstructures are calculated by means of the full-potential linear augmented
plane wave method, using the Tran-Blaha modified Becke-Johnson potential. The
calculated band gap of 1.23 eV is in agreement with the experimental value of
1.2 eV. The carrier concentration- and temperature dependent thermoelectric
properties of CuGaTe$_2$ are derived, and a figure of merit of $zT= 1.69$ is
obtained at 950 K for a hole concentration of $3.7\cdot10^{19}$ cm$^{-3}$, in
agreement with a recent experimental finding of $zT= 1.4$, confirming that
CuGaTe$_2$ is a promising material for high temperature thermoelectric
applications. The good thermoelectric performance of p-type CuGaTe$_2$ is
associated with anisotropic transport from a combination of heavy and light
bands. Also for CuSbS$_2$ (chalcostibite) a better performance is obtained for
p-type than for n-type doping. The variation of the thermopower as a function
of temperature and concentration suggests that CuSbS$_2$ will be a good
thermoelectric material at low temperatures, similarly to the isostructural
CuBiS$_2$ compound.


title:
Contributions of artificial lighting sources on light pollution in Hong
  Kong measured through a night sky brightness monitoring network

abstract:
  Light pollution is a form of environmental degradation in which excessive
artificial outdoor lighting, such as street lamps, neon signs, and illuminated
signboards, affects the natural environment and the ecosystem. Poorly designed
outdoor lighting not only wastes energy, money, and valuable Earth resources,
but also robs us of our beautiful night sky. Effects of light pollution on the
night sky can be evaluated by the skyglow caused by these artificial lighting
sources, through measurements of the night sky brightness (NSB). The Hong Kong
Night Sky Brightness Monitoring Network (NSN) was established to monitor in
detail the conditions of light pollution in Hong Kong. Monitoring stations were
set up throughout the city covering a wide range of urban and rural settings to
continuously measure the variations of the NSB. Over 4.6 million night sky
measurements were collected from 18 distinct locations between May 2010 and
March 2013. This huge dataset, over two thousand times larger than our previous
survey, forms the backbone for studies of the temporal and geographical
variations of this environmental parameter and its correlation with various
natural and artificial factors. The concepts and methodology of the NSN were
presented here, together with an analysis of the overall night sky conditions
in Hong Kong. The average NSB in Hong Kong, excluding data affected by the
Moon, was 16.8 mag arcsec$^{-2}$, or 82 times brighter than the dark site
standard established by the International Astronomical Union (IAU). The urban
night sky was on average 15 times brighter than that in a rural location,
firmly establishing the effects of artificial lighting sources on the night
sky.


title:
On the Gauged Kahler Isometry in Minimal Supergravity Models of
  Inflation

abstract:
  In this paper we address the question how to discriminate whether the gauged
isometry group G_Sigma of the Kahler manifold Sigma that produces a D-type
inflaton potential in a Minimal Supergravity Model is elliptic, hyperbolic or
parabolic. We show that the classification of isometries of symmetric cosets
can be extended to non symmetric Sigma.s if these manifolds satisfy additional
mathematical restrictions. The classification criteria established in the
mathematical literature are coherent with simple criteria formulated in terms
of the asymptotic behavior of the Kahler potential K(C) = 2 J(C) where the real
scalar field C encodes the inflaton field. As a by product of our analysis we
show that phenomenologically admissible potentials for the description of
inflation and in particular alpha-attractors are mostly obtained from the
gauging of a parabolic isometry, this being, in particular the case of the
Starobinsky model. Yet at least one exception exists of an elliptic
alpha-attractor, so that neither type of isometry can be a priori excluded. The
requirement of regularity of the manifold Sigma poses instead strong
constraints on the alpha-attractors and reduces their space considerably.
Curiously there is a unique integrable alpha-attractor corresponding to a
particular value of this parameter.

categories: hep-th astro-ph.CO gr-qc hep-ph math-ph math.MP


title:
Contributions of supernovae type II & Ib/c to the galactic chemical
  evolution

abstract:
  The supernovae SN II & Ib/c make major stellar nucleosynthetic contributions
to the inventories of the stable nuclides during the chemical evolution of the
galaxy. A case study is performed here with the help of recently developed
numerical simulations of the galactic chemical evolution in the solar
neighbourhood to understand the contributions of the SN II and Ib/c by making a
comparison of the stellar nucleosynthetic yields obtained by two leading groups
in the field. These stellar nucleosynthetic yields differ in terms of the
treatment of stellar evolution and nucleosynthesis. The formulation for the
galactic chemical evolution is developed for the recently revised solar
metallicity of 0.014. Further, the recent nucleosynthetic yields of the stellar
models based on the revised solar metallicity are also used. The analysis
suggest that it could be difficult to explain in a self-consistent manner the
various features associated with the elemental evolutionary trends over the
galactic timescales by any single adopted stellar nucleosynthetic model of SN
II & Ib/c.


title:
A Comparative Study of Downlink MIMO Cellular Networks with Co-located
  and Distributed Base-Station Antennas

abstract:
  Despite the common belief that substantial capacity gains can be achieved by
using more antennas at the base-station (BS) side in cellular networks, the
effect of BS antenna topology on the capacity scaling behavior is little
understood. In this paper, we present a comparative study on the ergodic
capacity of a downlink single-user multiple-input-multiple-output (MIMO) system
where BS antennas are either co-located at the center or grouped into uniformly
distributed antenna clusters in a circular cell. By assuming that the number of
BS antennas and the number of user antennas go to infinity with a fixed ratio
$L\gg 1$, the asymptotic analysis reveals that the average per-antenna
capacities in both cases logarithmically increase with $L$, but in the orders
of $\log_2 L$ and $\tfrac{\alpha}{2}\log_2 L$, for the co-located and
distributed BS antenna layouts, respectively, where $\alpha>2$ denotes the
path-loss factor. The analysis is further extended to the multi-user case where
a 1-tier (7-cell) MIMO cellular network with $K\gg 1$ uniformly distributed
users in each cell is considered. By assuming that the number of BS antennas
and the number of user antennas go to infinity with a fixed ratio $L\gg K$, an
asymptotic analysis is presented on the downlink rate performance with block
diagonalization (BD) adopted at each BS. It is shown that the average
per-antenna rates with the co-located and distributed BS antenna layouts scale
in the orders of $\log_2 \tfrac{L}{K}$ and $\log_2
\frac{(L-K+1)^{\alpha/2}}{K}$, respectively. The rate performance of MIMO
cellular networks with small cells is also discussed, which highlights the
importance of employing a large number of distributed BS antennas for the
next-generation cellular networks.


title:
Computation of eigenvalue sensitivity to base flow modifications in a
  discrete framework: Application to open-loop control

abstract:
  A fully discrete formalism is introduced to perform stability analysis of a
turbulent compressible flow whom dynamics is modeled with the Reynolds-Averaged
Navier-Stokes (RANS) equations. The discrete equations are linearized using
finite differences and the Jacobian is computed using repeated evaluation of
the residuals. Stability of the flow is assessed solving an eigenvalue problem.
The sensitivity gradients which indicate regions of the flow where a passive
control device could stabilize the unstable eigenvalues are defined within this
fully discrete framework. Second order finite differences are applied to the
discrete residual to compute the gradients. In particular, the sensitivity
gradients are shown to be linked to the Hessian of the RANS equations. The
introduced formalism and linearization method are generic: the code used to
evaluate the residual of the RANS equations can be used in a black box manner,
and the complex linearization of the Hessian is avoided. The method is tested
on a two dimensional deep cavity case, the flow is turbulent with a Reynolds
number equal to 860 000 and compressible with a Mach number of 0.8. Several
turbulence models and numerical schemes are used to validate the method.
Physical features of the flow are recovered, such as the fundamental frequency
of the natural flow as well as acoustic mechanisms, suggesting the validity of
the method. The sensitivity gradients are then computed and validated, the
error in predicting the eigenvalue variation being found less than 3\%. Control
maps using a small steady control device are finally obtained, indicating that
the control area should be chosen in the vicinity of the leading edge of the
cavity.


title: Lens optics and the continuity problems of the ABCD matrix

abstract:
  Paraxial lens optics is discussed to study the continuity properties of the
$ABCD$ beam transfer matrix. The two-by-two matrix for the one-lens camera-like
system can be converted to an equi-diagonal form by a scale transformation,
leaving the off-diagonal elements invariant. It is shown that the matrix
remains continuous during the focusing process, but this transition is not
analytic. However, its first derivative is still continuous, which leads to the
concept of "tangential continuity." It is then shown that this tangential
continuity is applicable to $ABCD$ matrices pertinent to periodic optical
systems, where the equi-diagonalization is achieved by a similarity
transformation using rotations. It is also noted that both the scale
transformations and the rotations can be unified within the framework of
Hermitian transformations.


title:
A Fast Decodable Full-Rate STBC with High Coding Gain for 4x2 MIMO
  Systems

abstract:
  In this work, a new fast-decodable space-time block code (STBC) is proposed.
The code is full-rate and full-diversity for 4x2 multiple-input multiple-output
(MIMO) transmission. Due to the unique structure of the codeword, the proposed
code requires a much lower computational complexity to provide
maximum-likelihood (ML) decoding performance. It is shown that the ML decoding
complexity is only O(M^{4.5}) when M-ary square QAM constellation is used.
Finally, the proposed code has highest minimum determinant among the
fast-decodable STBCs known in the literature. Simulation results prove that the
proposed code provides the best bit error rate (BER) performance among the
state-of-the-art STBCs.


title:
A High False Positive Rate for Kepler Planetary Candidates of Giant
  Stars using Asterodensity Profiling

abstract:
  Asterodensity Profiling (AP) is a relatively new technique for studying
transit light curves. By comparing the mean stellar density derived from the
transit light curve to that found through some independent method, AP provides
information on several useful properties such as orbital eccentricity and
blended light. We present an AP survey of 41 Kepler Objects of Interest (KOIs),
with a single transiting candidate, for which the target star's mean stellar
density has been measured using asteroseismology. The ensemble distribution of
the AP measurements for the 31 dwarf stars in our sample shows excellent
agreement with the spread expected if the KOIs were genuine and have realistic
eccentricities. In contrast, the same test for the 10 giants in our sample
reveals significant incompatibility at 4$\sigma$ confidence. Whilst extreme
eccentricities could be invoked, this hypothesis requires four of the KOIs to
contact their host star at periastron passage, including the recently claimed
confirmation of Kepler-91b. After carefully examining several hypotheses, we
conclude that the most plausible explanation is that the transiting objects
orbit a different star to that measured with asteroseismology - cases we define
as false-positives. Based on the AP distribution, we estimate a false positive
rate for Kepler's giant stars with a single transiting object of
FPR$\simeq70\pm30$%.


title: The dynamics of isolated Local Group galaxies

abstract:
  We measured velocities of 862 individual red giant stars in seven isolated
dwarf galaxies in the Local Group: NGC 6822, IC 1613, VV 124 (UGC 4879), the
Pegasus dwarf irregular galaxy (DDO 216), Leo A, Cetus, and Aquarius (DDO 210).
We also computed velocity dispersions, taking into account the measurement
uncertainties on individual stars. None of the isolated galaxies is denser than
the densest Local Group satellite galaxy. Furthermore, the isolated dwarf
galaxies have no obvious distinction in the velocity dispersion--half-light
radius plane from the satellite galaxies of the Milky Way and M31. The
similarity of the isolated and satellite galaxies' dynamics and structural
parameters imposes limitations on environmental solutions to the
too-big-to-fail problem, wherein there are fewer dense dwarf satellite galaxies
than would be expected from cold dark matter simulations. This data set also
has many other applications for dwarf galaxy evolution, including the
transformation of dwarf irregular into dwarf spheroidal galaxies. We intend to
explore these issues in future work.


title:
What is the Physical Origin of Strong Lya Emission? I. Demographics of
  Lya Emitter Structures

abstract:
  We present the results of structure analyses for a large sample of 426 Lya
emitters (LAEs) at z~2.2 that are observed with HST/ACS and WFC3-IR by deep
extra-galactic legacy surveys. We confirm that the merger fraction and the
average ellipticity of LAE's stellar component are 10-30 % and 0.4-0.6,
respectively, that are comparable with previous study results. We successfully
identify that some LAEs have a spatial offset between Lya and stellar-continuum
emission peaks, d_Lya, by ~2.5-4 kpc beyond our statistical errors. To uncover
the physical origin of strong Lya emission found in LAEs, we investigate Lya
equivalent width (EW) dependences of these three structural parameters, merger
fraction, d_Lya, and ellipticity of stellar distribution in the range of
EW(Lya)=20-250A. Contrary to expectations, we find that merger fraction does
not significantly increase with Lya EW. We reveal an anti-correlation between
d_Lya and EW(Lya) by Kolmogorov-Smirnov (KS) test. There is a trend that the
LAEs with a large Lya EW have a small ellipticity. This is consistent with the
recent theoretical claims that Lya photons can more easily escape from face-on
disks having a small ellipticity, due to less inter-stellar gas along the line
of sight, although our KS test indicates that this trend is not statistically
significant. Our results of Lya-EW dependence generally support the idea that
an HI column density is a key quantity determining Lya emissivity.


title:
The Hunt for Exomoons with Kepler (HEK): IV. A Search for Moons around
  Eight M-Dwarfs

abstract:
  With their smaller radii and high cosmic abundance, transiting planets around
cool stars hold a unique appeal. As part of our on-going project to measure the
occurrence rate of extrasolar moons, we here present results from a survey
focussing on eight Kepler planetary candidates associated with M-dwarfs. Using
photodynamical modeling and Bayesian multimodal nested sampling, we find no
compelling evidence for an exomoon in these eight systems. Upper limits on the
presence of such bodies probe down to $\sim0.4M_{\oplus}$ in the best case. For
KOI-314, we are able to confirm the planetary nature of two out of the three
known transiting candidates using transit timing variations. Of particular
interest is KOI-314c, which is found to have a mass of
$1.0_{-0.3}^{+0.4}M_{\oplus}$, making it the lowest mass transiting planet
discovered to date. With a radius of $1.61_{-0.15}^{+0.16}R_{\oplus}$, this
Earth-mass world is likely enveloped by a significant gaseous envelope
comprising $\geq17_{-13}^{+12}$% of the planet by radius. We find evidence to
support the planetary nature of KOI-784 too via transit timing, but we advocate
further observations to verify the signals. In both systems, we infer that the
inner planet has a higher density than the outer world, which may be indicative
of photo-evaporation. These results highlight both the ability of Kepler to
search for sub-Earth mass moons and the exciting ancillary science which often
results from such efforts.


title:
Evidence for Large Temperature Fluctuations in Quasar Accretion Disks
  From Spectral Variability

abstract:
  The well-known bluer-when-brighter trend observed in quasar variability is a
signature of the complex processes in the accretion disk, and can be a probe of
the quasar variability mechanism. Using a sample of 604 variable quasars with
repeat spectra in SDSS-I/II, we construct difference spectra to investigate the
physical causes of this bluer-when-brighter trend. The continuum of our
composite difference spectrum is well-fit by a power-law, with a spectral index
in excellent agreement with previous results. We measure the spectral
variability relative to the underlying spectra of the quasars, which is
independent of any extinction, and compare to model predictions. We show that
our SDSS spectral variability results cannot be produced by global accretion
rate fluctuations in a thin disk alone. However, we find that a simple model of
a inhomogeneous disk with localized temperature fluctuations will produce
power-law spectral variability over optical wavelengths. We show that the
inhomogeneous disk will provide good fits to our observed spectral variability
if the disk has large temperature fluctuations in many independently varying
zones, in excellent agreement with independent constraints from quasar
microlensing disk sizes, their strong UV spectral continuum, and single-band
variability amplitudes. Our results provide an independent constraint on quasar
variability models, and add to the mounting evidence that quasar accretion
disks have large localized temperature fluctuations.


title: Do Giant Molecular Clouds Care About the Galactic Structure?

abstract:
  We investigate the impact of galactic environment on the properties of
simulated giant molecular clouds formed in a M83-type barred spiral galaxy. Our
simulation uses a rotating stellar potential to create the grand design
features and resolves down to 1.5 pc. From the comparison of clouds found in
the bar, spiral and disc regions, we find that the typical GMC is environment
independent, with a mass of 5e+5 Msun and radius 11 pc. However, the fraction
of clouds in the property distribution tails varies between regions, with
larger, more massive clouds with a higher velocity dispersion being found in
greatest proportions in the bar, spiral and then disc. The bar clouds also show
a bimodality that is not reflected in the spiral and disc clouds except in the
surface density, where all three regions show two distinct peaks. We identify
these features as being due to the relative proportion of three cloud types,
classified via the mass-radius scaling relation, which we label A, B and C.
Type A clouds have the typical values listed above and form the largest
fraction in each region. Type B clouds are massive giant molecular associations
while Type C clouds are unbound, transient clouds that form in dense filaments
and tidal tails. The fraction of each clouds type depends on the cloud-cloud
interactions, which cause mergers to build up the GMA Type Bs and tidal
features in which the Type C clouds are formed. The number of cloud
interactions is greatest in the bar, followed by the spiral, causing a higher
fraction of both cloud types compared to the disc. While the cloud types also
exist in lower resolution simulations, their identification becomes more
challenging as they are not well separated populations on the mass-radius
relation or distribution plots. Finally, we compare the results for three star
formation models to estimate the star formation rate and efficiency in each
region.


title:
Karl G. Jansky Very Large Array observations of cold dust and molecular
  gas in starbursting quasar host galaxies at z~4.5

abstract:
  We present Karl G. Jansky Very Large Array (VLA) observations of 44 GHz
continuum and CO J=2-1 line emission in BR1202-0725 at z=4.7 (a starburst
galaxy and quasar pair) and BRI1335-0417 at z=4.4 (also hosting a quasar). With
the full 8 GHz bandwidth capabilities of the upgraded VLA, we study the
(rest-frame) 250 GHz thermal dust continuum emission for the first time along
with the cold molecular gas traced by the Low-J CO line emission. The measured
CO J=2-1 line luminosities of BR1202-0725 are L'(CO) = (8.7+/-0.8)x10^10 K km/s
pc^2 and L'(CO) = (6.0+/-0.5)x10^10 K km/s pc^2 for the submm galaxy (SMG) and
quasar, which are equal to previous measurements of the CO J=5-4 line
luminosities implying thermalized line emission and we estimate a combined cold
molecular gas mass of ~9x10^10 Msun. In BRI1335-0417 we measure L'(CO) =
(7.3+/-0.6)x10^10 K km/s pc^2. We detect continuum emission in the SMG
BR1202-0725 North (S(44GHz) = 51+/-6 microJy), while the quasar is detected
with S(44GHz) = 24+/-6 microJy and in BRI1335-0417 we measure S(44GHz) = 40+/-7
microJy. Combining our continuum observations with previous data at
(rest-frame) far-infrared and cm-wavelengths, we fit three component models in
order to estimate the star-formation rates. This spectral energy distribution
fitting suggests that the dominant contribution to the observed 44~GHz
continuum is thermal dust emission, while either thermal free-free or
synchrotron emission contributes less than 30%.


title:
Galaxy phase-space density data exclude Bose-Einstein condensate Axion
  Dark Matter

abstract:
  Light scalars (as the axion) with mass m ~ 10^{-22} eV forming a
Bose-Einstein condensate (BEC) exhibit a Jeans length in the kpc scale and were
therefore proposed as dark matter (DM) candidates. Our treatment here is
generic, independent of the particle physics model and applies to all DM BEC,
in or out of equilibrium. Two observed quantities crucially constrain DM in an
inescapable way: the average DM density rho_{DM} and the phase-space density Q.
The observed values of rho_{DM} and Q in galaxies today constrain both the
possibility to form a BEC and the DM mass m. These two constraints robustly
exclude axion DM that decouples just after the QCD phase transition. Moreover,
the value m ~ 10^{-22} eV can only be obtained with a number of
ultrarelativistic degrees of freedom at decoupling in the trillions which is
impossible for decoupling in the radiation dominated era. In addition, we find
for the axion vacuum misalignment scenario that axions are produced strongly
out of thermal equilibrium and that the axion mass in such scenario turns to be
17 orders of magnitude too large to reproduce the observed galactic structures.
Moreover, we also consider inhomogenous gravitationally bounded BEC's supported
by the bosonic quantum pressure independently of any particular particle
physics scenario. For a typical size R ~ kpc and compact object masses M ~ 10^7
Msun they remarkably lead to the same particle mass m ~ 10^{-22} eV as the BEC
free-streaming length. However, the phase-space density for the gravitationally
bounded BEC's turns to be more than sixty orders of magnitude smaller than the
galaxy observed values. We conclude that the BEC's and the axion cannot be the
DM particle. However, an axion in the mili-eV scale may be a relevant source of
dark energy through the zero point cosmological quantum fluctuations.


title:
Excitation temperature of the warm neutral medium as a new probe of the
  Lyman-{\alpha} radiation field

abstract:
  We use the Karl G. Jansky Very Large Array (VLA) to conduct a
high-sensitivity survey of neutral hydrogen (HI) absorption in the Milky Way.
In combination with corresponding HI emission spectra obtained mostly with the
Arecibo Observatory, we detect a widespread warm neutral medium (WNM) component
with excitation temperature <Ts>= 7200 (+1800,-1200) K (68% confidence). This
temperature lies above theoretical predictions based on collisional excitation
alone, implying that Ly-{\alpha} scattering, the most probable additional
source of excitation, is more important in the interstellar medium (ISM) than
previously assumed. Our results demonstrate that HI absorption can be used to
constrain the Ly-{\alpha} radiation field, a critical quantity for studying the
energy balance in the ISM and intergalactic medium yet notoriously difficult to
model because of its complicated radiative transfer, in and around galaxies
nearby and at high redshift.


title:
Dependence of the outer density profiles of halos on their mass
  accretion rate

abstract:
  We present a systematic study of the density profiles of LCDM halos, focusing
on the outer regions, 0.1 < r/Rvir < 9. We show that the median and mean
profiles of halo samples of a given peak height exhibit significant deviations
from the universal analytic profiles discussed previously in the literature,
such as the Navarro-Frenk-White and Einasto profiles, at radii r > 0.5 R200m.
In particular, at these radii the logarithmic slope of the median density
profiles of massive or rapidly accreting halos steepens more sharply than
predicted. The steepest slope of the profiles occurs at r ~ R200m, and its
absolute value increases with increasing peak height or mass accretion rate,
reaching slopes of -4 and steeper. Importantly, we find that the outermost
density profiles at r > R200m are remarkably self-similar when radii are
rescaled by R200m. This self-similarity indicates that radii defined with
respect to the mean density are preferred for describing the structure and
evolution of the outer profiles. However, the inner density profiles are most
self-similar when radii are rescaled by R200c. We propose a new fitting formula
that describes the median and mean profiles of halo samples selected by their
peak height or mass accretion rate with accuracy < 10% at all radii, redshifts
and masses we studied, r < 9 Rvir, 0 < z < 6 and Mvir > 1.7E10 Msun/h. We
discuss observational signatures of the profile features described above, and
show that the steepening of the outer profile should be detectable in future
weak-lensing analyses of massive clusters. Such observations could be used to
estimate the mass accretion rate of cluster halos.


title: New Red Jewels in Coma Berenices

abstract:
  We have used Sloan Digital Sky Survey-III (SDSS-III) Apache Point Observatory
Galactic Evolution Experiment (APOGEE) radial velocity observations in the
near-infrared $H$-band to explore the membership of the nearby ($86.7 \pm 0.9$
pc) open cluster Coma Berenices (Melotte 111), concentrating on the
poorly-populated low-mass end of the main sequence. Using SDSS-III APOGEE
radial velocity measurements, we confirm the membership of eight K/M dwarf
members, providing the first confirmed low-mass members of the Coma Berenices
cluster. Using $R\sim2000$ spectra from IRTF-SpeX, we confirm the independently
luminosity classes of these targets, and find their metallicities to be
consistent with the known solar mean metallicity of Coma Berenices and of M
dwarfs in the Solar neighborhood. In addition, the APOGEE spectra have enabled
measurement of $v\sin i$ for each target and detection for the first time of
the low-mass secondary components of the known binary systems Melotte 111 102
and Melotte 111 120, as well as identification of the previously unknown binary
system 2MASS J12214070+2707510. Finally, we use Kilodegree Extremely Little
Telescope (KELT) photometry to measure photometric variability and rotation
periods for a subset of the Coma Berenices members.


title: Closed String Amplitudes as Single-Valued Open String Amplitudes

abstract:
  We show that the single trace heterotic N-point tree-level gauge amplitude
A_HET can be obtained from the corresponding type I amplitude A_I by the
single-valued (sv) projection: A_HET=sv(A_I). This projection maps multiple
zeta values to single-valued multiple zeta values. The latter represent a
subclass of multiple zeta values originating from single-valued multiple
polylogarithms at unity. Similar relations between open and closed string
amplitudes or amplitudes of different string vacua can be established. As a
consequence the alpha'-expansion of a closed string amplitude is dictated by
that of the corresponding open string amplitude. The combination of
single-valued projections, Kawai-Lewellen-Tye relations and Mellin
correspondence reveal a unity of all tree-level open and closed superstring
amplitudes together with the maximally supersymmetric Yang-Mills and
supergravity theories.


title: Consciousness as a State of Matter

abstract:
  We examine the hypothesis that consciousness can be understood as a state of
matter, "perceptronium", with distinctive information processing abilities. We
explore five basic principles that may distinguish conscious matter from other
physical systems such as solids, liquids and gases: the information,
integration, independence, dynamics and utility principles. If such principles
can identify conscious entities, then they can help solve the quantum
factorization problem: why do conscious observers like us perceive the
particular Hilbert space factorization corresponding to classical space (rather
than Fourier space, say), and more generally, why do we perceive the world
around us as a dynamic hierarchy of objects that are strongly integrated and
relatively independent? Tensor factorization of matrices is found to play a
central role, and our technical results include a theorem about Hamiltonian
separability (defined using Hilbert-Schmidt superoperators) being maximized in
the energy eigenbasis. Our approach generalizes Giulio Tononi's integrated
information framework for neural-network-based consciousness to arbitrary
quantum systems, and we find interesting links to error-correcting codes,
condensed matter criticality, and the Quantum Darwinism program, as well as an
interesting connection between the emergence of consciousness and the emergence
of time.


title:
Black hole evolution: II. Spinning black holes in a supernova-driven
  turbulent interstellar medium

abstract:
  Supermassive black holes (BH) accrete gas from their surroundings and
coalesce with companions during galaxy mergers, and both processes change the
BH mass and spin. By means of high-resolution hydrodynamical simulations of
galaxies, either idealised or embedded within the cosmic web, we explore the
effects of interstellar gas dynamics and external perturbations on BH spin
evolution. All these physical quantities were evolved on-the-fly in a
self-consistent manner. We use a `maximal' model to describe the turbulence
induced by stellar feedback to highlight its impact on the angular momentum of
the gas accreted by the BH. Periods of intense star formation are followed by
phases where stellar feedback drives large-scale outflows and hot bubbles. We
find that BH accretion is synchronised with star formation, as only when gas is
cold and dense do both processes take place. During such periods, gas motion is
dominated by consistent rotation. On the other hand, when stellar feedback
becomes substantial, turbulent motion randomises gas angular momentum. However
BH accretion is strongly suppressed in that case, as cold and dense gas is
lacking. In our cosmological simulation, at very early times (z>6), the
galactic disc has not yet settled and no preferred direction exists for the
angular momentum of the accreted gas, so the BH spin remains low. As the gas
settles into a disc (6>z>3), the BH spin then rapidly reaches its maximal
value. At lower redshifts (z<3), even when galaxy mergers flip the direction of
the angular momentum of the accreted gas, causing it to counter-rotate, the BH
spin magnitude only decreases modestly and temporarily. Should this be a
typical evolution scenario for BH, it potentially has dramatic consequences
regarding their origin and assembly, as accretion on maximally spinning BH
embedded in thin Shakura-Sunyaev disc is significantly reduced.


title: Radio Supernovae in the Local Universe

abstract:
  In the last three decades, about 50 radio supernovae have been detected as a
result of targeted searches of optically discovered supernovae in the local
universe. Despite this relatively small number some diversity among them has
already been identified which is an indication of the underlying richness of
radio supernovae waiting to be discovered. For example, comparison of star
formation and supernova discovery rate imply that as many as half of the
supernovae remain undetected in the traditional optical searches, either
because of intrinsic dimness or due to dust obscuration. This has far reaching
consequences to the models of stellar and galaxy evolution. A radio sky survey
would be ideal to uncover larger supernova population. Transient radio sky
would benefit significantly from such a survey. With the advent of advanced
gravitational wave detectors a new window is set to open on the local Universe.
Localization of these gravitational detectors is poor to identify
electromagnetic counterparts of the gravitational wave sources. However, the
longer lasting radio emission accompanied in these sources could be effectively
identified in a radio sky survey. We advocate a medium area ($\approx$ a few
thousand $\rm deg^{2}$) radio sky survey at C-band. Alternatively, a survey at
S-band has advantage of larger sky coverage without serious loss of the science
case as presented here. Understanding the background in radio sky will be of
paramount importance for the upcoming sensitive radio facilities including the
Square Kilometer Array.


title:
Transverse Parton Distribution Functions at
  Next-To-Next-To-Leading-Order

abstract:
  We present a perturbative calculation of the transverse parton distribution
functions in all partonic channels up to next-to-next-to-leading order based on
a gauge invariant operator definition. We demonstrate for the first time that
such a definition works beyond the first non-trivial order. We extract the
coefficient functions relevant for a next-to-next-to-next-to-leading
logarithmic $q_T$ resummation in a large class of processes at hadron
colliders.