title:
New terms for scalar multi-Galileon models and application to SO(N) and
  SU(N) group representations

abstract:
  We investigate a new class of scalar multi-galileon models, which is not
included in the commonly admitted general formulation of generalized
multi-galileons. The Lagrangians of this class of models, some of them having
already been introduced in previous works, are specific to multi-galileon
theories, and vanish in the single galileon case. We examine them in details,
discussing in particular some hidden symmetry properties which can be made
explicit by adding total derivatives to these Lagrangians. These properties
allow us to describe the possible dynamics for these new Lagrangians in the
case of multi-galileons in the fundamental representation of a SO(N) and SU(N)
global symmetry group, as well as in the adjoint representation of a SU(N)
global symmetry group. We perform in parallel an exhaustive examination of some
of these models, finding a complete agreement with the dynamics obtained using
the symmetry properties. Finally, we conclude by discussing what could be the
most general multi-galileon theory, as well as the link between scalar and
vector multi-galileon models.


title: A revisit to scalar dark matter with radiative corrections

abstract:
  Extended Higgs sectors have been studied extensively in context of dark
matter phenomenology in tandem with other aspects. In this study, we compute
radiative corrections to the dark matter-Higgs portal coupling, which is in
fact a common feature of all scalar dark matter models irrespective of the
hypercharge of the multiplet from which the dark matter candidate emerges. We
select the popular inert doublet model (IDM) as a prototype in order to
demonstrate the impact of the next-to-leading order corrections, thereby
probing the plausibility of extending the allowed parameter space through
quantum effects. Given that the tree level portal coupling is a \emph{prima
facie} free parameter, the percentage change from loop effects can be large.
This modifies the dark matter phenomenology at a quantitative level. It also
encourages one to include loop corrections to all other interactions that are
deemed relevant in this context.


title: The L - \sigma\ relation for HII galaxies in green

abstract:
  The correlation between emission-line luminosity (L) and profile width
(sigma) for HII Galaxies provides a powerful method to measure the distances to
galaxies over a wide range of redshifts. In this paper we use SDSS
spectrophotometry to explore the systematics of the correlation using the
[OIII]5007 lines instead of Halpha or Hbeta to measure luminosities and line
widths. We also examine possible systematic effects involved in measuring the
profile-widths and the luminosities through different apertures. We find that
the green L-sigma relation defined using [OIII]5007 luminosities is
significantly more sensitive than Hbeta to the effects of age and the physical
conditions of the nebulae, which more than offsets the advantage of the higher
strength of the [OIII]5007 lines. We then explore the possibility of mixing
[OIII]5007 profile-widths with SDSS Hbeta luminosities using the Hubble
constant H0 to quantify the possible systematic effects. We find the mixed
L(Hbeta) sigma[OIII] relation to be at least as powerful as the canonical
L-sigma relation as a distance estimator, and we show that the evolutionary
corrections do not change the slope and the scatter of the correlation, and
therefore, do not bias the L-sigma distance indicator at high redshifts.
Locally, however, the luminosities of the Giant HII Regions that provide the
zero-point calibrators are sensitive to evolutionary corrections and may bias
the Hubble constant if their mean ages, as measured by the equivalent widths of
Hbeta, are significantly different from the mean age of the HII Galaxies. Using
a small sample of 16 ad-hoc zero point calibrators we obtain a value of H0 =
66.4\pm4.5 km s^-1 Mpc^-1 for the Hubble constant, which is fully consistent
with the best modern determinations, and that is not biased by evolutionary
corrections.


title: Hyperuniformity of Quasicrystals

abstract:
  Hyperuniform systems, which include crystals, quasicrystals and special
disordered systems, have attracted considerable recent attention, but rigorous
analyses of the hyperuniformity of quasicrystals have been lacking because the
support of the spectral intensity is dense and discontinuous. We employ the
integrated spectral intensity, $Z(k)$, to quantitatively characterize the
hyperuniformity of quasicrystalline point sets generated by projection methods.
The scaling of $Z(k)$ as $k$ tends to zero is computed for one-dimensional
quasicrystals and shown to be consistent with independent calculations of the
variance, $\sigma^2(R)$, in the number of points contained in an interval of
length $2R$. We find that one-dimensional quasicrystals produced by projection
from a two-dimensional lattice onto a line of slope $1/\tau$ fall into distinct
classes determined by the width of the projection window. For a countable dense
set of widths, $Z(k) \sim k^4$; for all others, $Z(k)\sim k^2$. This
distinction suggests that measures of hyperuniformity define new classes of
quasicrystals in higher dimensions as well.


title: Critical scaling in hidden state inference for linear Langevin dynamics

abstract:
  We consider the problem of inferring the dynamics of unknown (i.e. hidden)
nodes from a set of observed trajectories and study analytically the average
prediction error and the typical relaxation time of correlations between
errors. We focus on a stochastic linear dynamics of continuous degrees of
freedom interacting via random Gaussian couplings in the infinite network size
limit. The expected error on the hidden time courses can be found as the
equal-time hidden-to-hidden covariance of the probability distribution
conditioned on observations. In the stationary regime, we analyze the phase
diagram in the space of relevant parameters, namely the ratio between the
numbers of observed and hidden nodes, the degree of symmetry of the
interactions and the amplitudes of the hidden-to-hidden and hidden-to-observed
couplings relative to the decay constant of the internal hidden dynamics. In
particular, we identify critical regions in parameter space where the
relaxation time and the inference error diverge, and determine the
corresponding scaling behaviour.


title:
Structural characterization and statistical-mechanical model of
  epidermal patterns

abstract:
  In proliferating epithelia of mammalian skin, cells of irregular
polygonal-like shapes pack into complex nearly flat two-dimensional structures
that are pliable to deformations. In this work, we employ various sensitive
correlation functions to quantitatively characterize structural features of
evolving packings of epithelial cells across length scales in mouse skin. We
find that the pair statistics in direct and Fourier spaces of the cell
centroids in the early stages of embryonic development show structural
directional dependence, while in the late stages the patterns tend towards
statistically isotropic states. We construct a minimalist four-component
statistical-mechanical model involving effective isotropic pair interactions
consisting of hard-core repulsion and extra short-ranged soft-core repulsion
beyond the hard core, whose length scale is roughly the same as the hard core.
The model parameters are optimized to match the sample pair statistics in both
direct and Fourier spaces. By doing this, the parameters are biologically
constrained. Our model predicts essentially the same polygonal shape
distribution and size disparity of cells found in experiments as measured by
Voronoi statistics. Moreover, our simulated equilibrium liquid-like
configurations are able to match other nontrivial unconstrained statistics,
which is a testament to the power and novelty of the model. We discuss ways in
which our model might be extended so as to better understand morphogenesis (in
particular the emergence of planar cell polarity), wound-healing, and disease
progression processes in skin, and how it could be applied to the design of
synthetic tissues.

categories: cond-mat.stat-mech cond-mat.soft physics.bio-ph physics.comp-ph


title: A recursive construction for simple $t$-designs using resolution

abstract:
  This work presents a recursive construction for simple $t$-designs using
resolutions of the ingredient designs. The result extends a construction of
$t$-designs in our recent paper [39]. Essentially, the method in [39] describes
the blocks of a constructed design as a collection of block unions from a
number of appropriate pairs of disjoint ingredient designs. Now, if some pairs
of these ingredient $t$-designs have both a suitable $s$-resolution, then we
can define a distance mapping on their resolution classes. Using this mapping
enables us to have more possibilities for forming blocks from those pairs. The
method makes it possible for constructing many new simple $t$-designs. We give
some application results of the new construction.


title:
Multi-Purpose Binomial Model: Fitting all Moments to the Underlying
  Geometric Brownian Motion

abstract:
  We construct a binomial tree model fitting all moments to the approximated
geometric Brownian motion. Our construction generalizes the classical
Cox-Ross-Rubinstein, the Jarrow-Rudd, and the Tian binomial tree models. The
new binomial model is used to resolve a discontinuity problem in option
pricing.


title: Statistical Mechanics of MAP Estimation: General Replica Ansatz

abstract:
  The large-system performance of MAP estimation is studied considering a
general distortion function when the observation vector is received through a
linear system with additive white Gaussian noise. The analysis considers the
system matrix to be chosen from the large class of rotationally invariant
random matrices. We take a statistical mechanical approach by introducing a
spin glass corresponding to the estimator, and employing the replica method for
the large-system analysis. In contrast to earlier replica based studies, our
analysis evaluates the general replica ansatz of the corresponding spin glass
and determines the asymptotic distortion of the estimator for any structure of
the replica correlation matrix. Consequently, the replica symmetric as well as
the Replica Symmetry (RS) breaking ansatz with $b$ steps of breaking is deduced
from the given general replica ansatz. The generality of our distortion
function lets us derive a more general form of the MAP decoupling principle.
Based on the general replica ansatz, we show that for any structure of the
replica correlation matrix, the vector-valued system decouples into a bank of
equivalent decoupled linear systems followed by MAP estimators. The structure
of the decoupled linear system is further studied under both the RS and the
Replica Symmetry Breaking (RSB) assumptions. For $b$ steps of RSB, the
decoupled system is found to be an additive system with a noise term given as
the sum of an independent Gaussian random variable with $b$ correlated
impairment terms. As an application of our study, we investigate large
compressive sensing systems by considering the $\ell_p$ minimization recovery
schemes. Our numerical investigations show that the replica symmetric ansatz
for $\ell_0$ norm recovery fails to give an accurate approximation of the mean
square error as the compression rate grows, and therefore, the RSB ans\"atze
are needed.


title: Core Sampling Framework for Pixel Classification

abstract:
  The intermediate map responses of a Convolutional Neural Network (CNN)
contain information about an image that can be used to extract contextual
knowledge about it. In this paper, we present a core sampling framework that is
able to use these activation maps from several layers as features to another
neural network using transfer learning to provide an understanding of an input
image. Our framework creates a representation that combines features from the
test data and the contextual knowledge gained from the responses of a
pretrained network, processes it and feeds it to a separate Deep Belief
Network. We use this representation to extract more information from an image
at the pixel level, hence gaining understanding of the whole image. We
experimentally demonstrate the usefulness of our framework using a pretrained
VGG-16 model to perform segmentation on the BAERI dataset of Synthetic Aperture
Radar(SAR) imagery and the CAMVID dataset.


title:
An Accurate Globally Conservative Subdomain Discontinuous Least-squares
  Scheme for Solving Neutron Transport Problems

abstract:
  In this work, we present a subdomain discontinuous least-squares (SDLS)
scheme for neutronics problems. Least-squares (LS) methods are known to be
inaccurate for problems with sharp total-cross section interfaces. In addition,
the least-squares scheme is known not to be globally conservative in
heterogeneous problems. In problems where global conservation is important,
e.g. k-eigenvalue problems, conservative treatment must be applied. We, in this
study, proposed a SDLS method that retains global conservation. Such a method
resembles the LS formulation in each subdomain without material interface and
differs from LS in that an additional least-squares interface term appears for
each interface. Scalar flux is continuous in each subdomain with continuous
finite element method (CFEM) while discontinuous on interfaces for every pair
of contiguous subdomains. SDLS numerical results are compared with those
obtained from other numerical methods with test problems having material
interfaces. High accuracy of scalar flux in fixed-source problems and
$k_\mathrm{eff}$ in eigenvalue problems are demonstrated.


title:
Three favorite sites occurs infinitely often for one-dimensional simple
  random walk

abstract:
  For a one-dimensional simple random walk $(S_t)$, for each time $t$ we say a
site $x$ is a favorite site if it has the maximal local time. In this paper, we
show that with probability 1 three favorite sites occurs infinitely often. Our
work is inspired by T\'oth (2001), and disproves a conjecture of Erd\"{o}s and
R\'ev\'esz (1984) and of T\'oth (2001).


title: On the geometry of the countably branching diamond graphs

abstract:
  In this article, the bi-Lipschitz embeddability of the sequence of countably
branching diamond graphs $(D_k^\omega)_{k\in\mathbb{N}}$ is investigated. In
particular it is shown that for every $\varepsilon>0$ and $k\in\mathbb{N}$,
$D_k^\omega$ embeds bi-Lipschiztly with distortion at most $6(1+\varepsilon)$
into any reflexive Banach space with an unconditional asymptotic structure that
does not admit an equivalent asymptotically uniformly convex norm. On the other
hand it is shown that the sequence $(D_k^\omega)_{k\in\mathbb{N}}$ does not
admit an equi-bi-Lipschitz embedding into any Banach space that has an
equivalent asymptotically midpoint uniformly convex norm. Combining these two
results one obtains a metric characterization in terms of graph preclusion of
the class of asymptotically uniformly convexifiable spaces, within the class of
separable reflexive Banach spaces with an unconditional asymptotic structure.
Applications to bi-Lipschitz embeddability into $L_p$-spaces and to some
problems in renorming theory are also discussed.


title:
The gravitational interaction between planets on inclined orbits and
  protoplanetary disks as the origin of primordial spin--orbit misalignments

abstract:
  Many of the observed spin--orbit alignment properties of exoplanets can be
explained in the context of the primordial disk misalignment model, in which an
initially aligned protoplanetary disk is torqued by a distant stellar companion
on a misaligned orbit, resulting in a precessional motion that can lead to
large-amplitude oscillations of the spin--orbit angle. We consider a variant of
this model in which the companion is a giant planet with an orbital radius of a
few au. Guided by the results of published numerical simulations, we model the
dynamical evolution of this system by dividing the disk into inner and outer
parts---separated at the location of the planet---that behave as distinct,
rigid disks. We show that the planet misaligns the inner disk even as the
orientation of the outer disk remains unchanged. In addition to the
oscillations induced by the precessional motion, whose amplitude is larger the
smaller the initial inner-disk-to-planet mass ratio, the spin--orbit angle also
exhibits a secular growth in this case---driven by ongoing mass depletion from
the disk---that becomes significant when the inner disk's angular momentum
drops below that of the planet. Altogether, these two effects can produce
significant misalignment angles for the inner disk, including retrograde
configurations. We discuss these results within the framework of the Stranded
Hot Jupiter scenario and consider their implications, including to the
interpretation of the alignment properties of debris disks.


title:
Lepton asymmetry, neutrino spectral distortions, and big bang
  nucleosynthesis

abstract:
  We calculate Boltzmann neutrino energy transport with self-consistently
coupled nuclear reactions through the weak-decoupling-nucleosynthesis epoch in
an early universe with significant lepton numbers. We find that the presence of
lepton asymmetry enhances processes which give rise to nonthermal neutrino
spectral distortions. Our results reveal how asymmetries in energy and entropy
density uniquely evolve for different transport processes and neutrino flavors.
The enhanced distortions in the neutrino spectra alter the expected big bang
nucleosynthesis light element abundance yields relative to those in the
standard Fermi-Dirac neutrino distribution cases. These yields, sensitive to
the shapes of the neutrino energy spectra, are also sensitive to the phasing of
the growth of distortions and entropy flow with time/scale factor. We analyze
these issues and speculate on new sensitivity limits of deuterium and helium to
lepton number.


title: Latest ATLAS results from Run 2

abstract:
  After the first LHC long shutdown with upgrades to the machine and the
detectors, since 2015 the ATLAS experiment recorded more than 30 fb-1 of
integrated luminosity of pp collision data at 13 TeV centre- of-mass energy.
The data collected to date, the detector and physics performance, and
measurements of Standard Model processes are reviewed briefly before
summarising the latest ATLAS results in the Brout- Englert-Higgs sector, where
substantial progress has been made since the discovery. Searches for physics
phenomena beyond the Standard Model are also summarized. These proceedings
reflect only a brief summary of the material presented at the conference.


title: Local Group Invariant Representations via Orbit Embeddings

abstract:
  Invariance to nuisance transformations is one of the desirable properties of
effective representations. We consider transformations that form a \emph{group}
and propose an approach based on kernel methods to derive local group invariant
representations. Locality is achieved by defining a suitable probability
distribution over the group which in turn induces distributions in the input
feature space. We learn a decision function over these distributions by
appealing to the powerful framework of kernel methods and generate local
invariant random feature maps via kernel approximations. We show uniform
convergence bounds for kernel approximation and provide excess risk bounds for
learning with these features. We evaluate our method on three real datasets,
including Rotated MNIST and CIFAR-10, and observe that it outperforms competing
kernel based approaches. The proposed method also outperforms deep CNN on
Rotated-MNIST and performs comparably to the recently proposed
group-equivariant CNN.


title: Shock and Rarefaction Waves in Generalized Hertzian Contact Models

abstract:
  In the present work motivated by generalized forms of the Hertzian dynamics
associated with granular crystals, we consider the possibility of such models
to give rise to both shock and rarefaction waves. Depending on the value $p$ of
the nonlinearity exponent, we find that both of these possibilities are
realizable. We use a quasi-continuum approximation of a generalized inviscid
Burgers model in order to predict the solution profile up to times near the
shock formation, as well as to estimate when it will occur. Beyond that time
threshold, oscillations associated with the discrete nature of the underlying
model emerge that cannot be captured by the quasi-continuum approximation. Our
analytical characterization of the above features is complemented by systematic
numerical computations.


title: From Exceptional Field Theory to Heterotic Double Field Theory via K3

abstract:
  In this paper we show how to obtain the heterotic double field theory from
exceptional field theory by breaking half of the supersymmetry. We focus on the
$\mathrm{SL}(5)$ exceptional field theory and show that when the extended space
contains a generalised $\mathrm{SU}(2)$-structure manifold one can define a
reduction to obtain the heterotic $\mathrm{SO}(3,n)$ double field theory. In
this picture, the reduction on the $\mathrm{SU}(2)$-structure breaks half of
the supersymmetry of the exceptional field theory and the gauge group of the
heterotic double field theory is given by the embedding tensor of the reduction
used. Finally, we study the example of a consistent truncation of M-theory on
K3 and recover the duality with the heterotic string on $T^3$. This suggests
that the extended space can be made sense of even in the case of non-toroidal
compactifications.


title: Diverse Sampling for Self-Supervised Learning of Semantic Segmentation

abstract:
  We propose an approach for learning category-level semantic segmentation
purely from image-level classification tags indicating presence of categories.
It exploits localization cues that emerge from training classification-tasked
convolutional networks, to drive a "self-supervision" process that
automatically labels a sparse, diverse training set of points likely to belong
to classes of interest. Our approach has almost no hyperparameters, is modular,
and allows for very fast training of segmentation in less than 3 minutes. It
obtains competitive results on the VOC 2012 segmentation benchmark. More,
significantly the modularity and fast training of our framework allows new
classes to efficiently added for inference.


title: Expanding FLew with a Boolean connective

abstract:
  We expand FLew with a unary connective whose algebraic counterpart is the
operation that gives the greatest complemented element below a given argument.
We prove that the expanded logic is conservative and has the Finite Model
Property. We also prove that the corresponding expansion of the class of
residuated lattices is an equational class.


title:
Probing QCD perturbation theory at high energies with continuum
  extrapolated lattice data

abstract:
  Precision tests of QCD perturbation theory are not readily available from
experimental data. The main reasons are systematic uncertainties due to the
confinement of quarks and gluons, as well as kinematical constraints which
limit the accessible energy scales. We here show how continuum extrapolated
lattice data may overcome such problems and provide excellent probes of
renormalized perturbation theory. This work corresponds to an essential step in
the ALPHA collaboration's project to determine the $\Lambda$-parameter in
3-flavour QCD. I explain the basic techniques used in the high energy regime,
namely the use of mass-independent renormalization schemes for the QCD coupling
constant in a finite Euclidean space time volume. When combined with finite
size techniques this allows one to iteratively step up the energy scale by
factors of 2, thereby quickly covering two orders of magnitude in scale. We may
then compare perturbation theory (with $\beta$-functions available up to 3-loop
order) to our non-perturbative data for a 1-parameter family of running
couplings. We conclude that a target precision of 3 percent for the
$\Lambda$-parameter requires non-perturbative data up to scales where
$\alpha_s\approx 0.1$, whereas the apparent precision obtained from applying
perturbation theory around $\alpha_s \approx 0.2$ can be misleading. This
should be taken as a general warning to practitioners of QCD perturbation
theory.


title:
Two-point Correlation Functions in Inhomogeneous and Anisotropic
  Cosmologies

abstract:
  Two-point correlation functions are ubiquitous tools of modern cosmology,
appearing in disparate topics ranging from cosmological inflation to late-time
astrophysics. When the background spacetime is maximally symmetric, invariance
arguments can be used to fix the functional dependence of this function as the
invariant distance between any two points. In this paper we introduce a novel
formalism which fixes this functional dependence directly from the isometries
of the background metric, thus allowing one to quickly assess the overall
features of Gaussian correlators without resorting to the full machinery of
perturbation theory. As an application we construct the CMB temperature
correlation function in one inhomogeneous (namely, an off-center LTB model) and
two spatially flat and anisotropic (Bianchi) universes, and derive their
covariance matrices in the limit of almost Friedmannian symmetry. We show how
the method can be extended to arbitrary N -point correlation functions and
illustrate its use by constructing three-point correlation functions in some
simple geometries.


title: Improved Pulse Shape Discrimination in EJ-301 liquid scintillators

abstract:
  Digital pulse shape discrimination has become readily available to
distinguish nuclear recoil and electronic recoil events in scintillation
detectors. We evaluate digital implementations of pulse shape discrimination
algorithms discussed in the literature, namely the Charge Comparison Method,
Pulse-Gradient Analysis, Fourier Series and Standard Event fitting. In
addition, we present a novel algorithm based on a Laplace Transform. Instead of
reducing the performance of these algorithms to a single Figure of Merit, we
evaluate them as function of recoil energy. Specifically, using commercial
EJ-301 liquid sctintillators, we examine both the resulting acceptance of
nuclear recoils at a given rejection level of electronic recoils, as well as
the purity of the selected nuclear recoil event samples. We find that both a
Standard Event fit and a Laplace Transform can be used to significantly improve
the discrimination capabilities over the whole energy range. Furthermore, we
show that the Charge Comparison Method performs poorly in accurately
identifying nuclear recoils.


title:
Chandra Reveals Heavy Obscuration and Circumnuclear Star Formation in
  Seyfert 2 Galaxy NGC 4968

abstract:
  We present the Chandra imaging and spectral analysis of NGC 4968, a nearby (z
= 0.00986) Seyfert 2 galaxy. We discover extended ($\sim$1 kpc) X-ray emission
in the soft band (0.5 - 2 keV) that is neither coincident with the narrow line
region nor the extended radio emission. Based on spectral modeling, it is
linked to on-going star formation ($\sim$2.6-4 M$_{\sun}$ yr$^{-1}$). The soft
emission at circumnuclear scales (inner $\sim$400 pc) originates from hot gas,
with kT $\sim$ 0.7 keV, while the most extended thermal emission is cooler (kT
$\sim$ 0.3 keV). We refine previous measurements of the extreme Fe K$\alpha$
equivalent width in this source (EW = 2.5$^{+2.6}_{-1.0}$ keV), which suggests
the central engine is completely embedded within Compton-thick levels of
obscuration. Using physically motivated models fit to the Chandra spectrum, we
derive a Compton-thick column density ($N_{\rm H} > 1.25\times10^{24}$
cm$^{-2}$) and an intrinsic hard (2-10 keV) X-ray luminosity of
$\sim$3-8$\times 10^{42}$ erg s$^{-1}$ (depending on the presumed geometry of
the obscurer), which is over two orders of magnitude larger than that observed.
The large Fe K$\alpha$ EW suggests a spherical covering geometry, which could
be confirmed with X-ray measurements above 10 keV. NGC 4968 is similar to other
active galaxies that exhibit extreme Fe K$\alpha$ EWs (i.e., $>$2 keV) in that
they also contain ongoing star formation. This work supports the idea that gas
associated with nuclear star formation may increase the covering factor of the
enshrouding gas and play a role in obscuring AGN.


title: Topological defects in open string field theory

abstract:
  We show how conformal field theory topological defects can relate solutions
of open string field theory for different boundary conditions. To this end we
generalize the results of Graham and Watts to include the action of defects on
boundary condition changing fields. Special care is devoted to the general case
when nontrivial multiplicities arise upon defect action. Surprisingly the
fusion algebra of defects is realized on open string fields only up to a (star
algebra) isomorphism.


title: Leveraging High Resolution Spectra to Understand Black Hole Spectra

abstract:
  For the past 17 years, both XMM-Newton and Chandra have brought the powerful
combination of high spatial and spectral resolution to the study of black hole
systems. Each of these attributes requires special consideration--- in
comparison to lower spatial resolution, CCD quality spectra--- when modeling
observations obtained by these spacecraft. A good understanding of the high
resolution spectra is in fact required to model properly lower resolution CCD
spectra, with the Reflection Grating Spectrometer (RGS) instrument on
XMM-Newton maintaining the highest "figure of merit" at soft X-ray energies for
all missions flying or currently planned for the next decade. Thanks to its
even higher spectral resolution, the use of Chandra-High Energy Transmission
Gratings (HETG), albeit with longer integration times, allows for one to bring
further clarity to RGS studies. A further promising route for continued studies
is the combination of high spectral resolution at soft X-rays, via RGS and/or
HETG, with contemporaneous broadband coverage extending to hard X-rays (e.g.,
NuSTAR or INTEGRAL spectra). Such studies offer special promise for answering
fundamental questions about accretion in black hole systems; however, they have
received only moderate consideration to date. This may be due in part to the
difficulty of analyzing high resolution spectra. In response, we must continue
to develop software tools that make the analysis of high resolution X-ray
spectra more accessible to the wider astrophysics community.


title: Precision neutrino experiments vs the Littlest Seesaw

abstract:
  We study to what extent upcoming precision neutrino oscillation experiments
will be able to exclude one of the most predictive models of neutrino mass and
mixing: the Littlest Seesaw. We show that this model provides a good fit to
current data, predicting eight observables from two input parameters, and
provide new assessments of its predictions and their correlations. We then
assess the ability to exclude this model using simulations of upcoming neutrino
oscillation experiments including the medium-distance reactor experiments JUNO
and RENO-50 and the long-baseline accelerator experiments DUNE and T2HK. We
find that an accurate determination of the currently least well measured
parameters, namely the atmospheric and solar angles and the CP phase $\delta$,
provide crucial independent tests of the model. For $\theta_{13}$ and the two
mass-squared differences, however, the model's exclusion requires a combination
of measurements coming from a varied experimental programme. Our results show
that the synergy and complementarity of future experiments will play a vital
role in efficiently discriminating between predictive models of neutrino
flavour, and hence, towards advancing our understanding of neutrino
oscillations in the context of the flavour puzzle of the Standard Model.


title:
SDSS-IV MaNGA: The Impact of Diffuse Ionized Gas on Emission-line
  Ratios, Interpretation of Diagnostic Diagrams, and Gas Metallicity
  Measurements

abstract:
  Diffuse Ionized Gas (DIG) is prevalent in star-forming galaxies. Using a
sample of 365 nearly face-on star-forming galaxies observed by MaNGA, we
demonstrate how DIG in star-forming galaxies impacts the measurements of
emission line ratios, hence the interpretation of diagnostic diagrams and
gas-phase metallicity measurements. At fixed metallicity, DIG-dominated low
H\alpha\ surface brightness regions display enhanced [SII]/H\alpha,
[NII]/H\alpha, [OII]/H\beta, and [OI]/H\alpha. The gradients in these line
ratios are determined by metallicity gradients and H\alpha\ surface brightness.
In line ratio diagnostic diagrams, contamination by DIG moves HII regions
towards composite or LI(N)ER-like regions. A harder ionizing spectrum is needed
to explain DIG line ratios. Leaky HII region models can only shift line ratios
slightly relative to HII region models, and thus fail to explain the
composite/LI(N)ER line ratios displayed by DIG. Our result favors ionization by
evolved stars as a major ionization source for DIG with LI(N)ER-like emission.
  DIG can significantly bias the measurement of gas metallicity and metallicity
gradients derived using strong-line methods. Metallicities derived using N2O2
are optimal because they exhibit the smallest bias and error. Using O3N2, R23,
N2=[NII]/H\alpha, and N2S2H\alpha\ (Dopita et al. 2016) to derive metallicities
introduces bias in the derived metallicity gradients as large as the gradient
itself. The strong-line method of Blanc et al. (2015; IZI hereafter) cannot be
applied to DIG to get an accurate metallicity because it currently contains
only HII region models which fail to describe the DIG.


title: A massive, quiescent, population II galaxy at a redshift of 2.1

abstract:
  Unlike spiral galaxies such as the Milky Way, the majority of the stars in
massive elliptical galaxies were formed in a short period early in the history
of the Universe. The duration of this formation period can be measured using
the ratio of magnesium to iron abundance ([Mg/Fe]), which reflects the relative
enrichment by core-collapse and type Ia supernovae. For local galaxies, [Mg/Fe]
probes the combined formation history of all stars currently in the galaxy,
including younger and metal-poor stars that were added during late-time
mergers. Therefore, to directly constrain the initial star-formation period, we
must study galaxies at earlier epochs. The most distant galaxy for which
[Mg/Fe] had previously been measured is at z~1.4, with
[Mg/Fe]=0.45(+0.05,-0.19). A slightly earlier epoch (z~1.6) was probed by
stacking the spectra of 24 massive quiescent galaxies, yielding an average
[Mg/Fe] of 0.31+/-0.12. However, the relatively low S/N of the data and the use
of index analysis techniques for both studies resulted in measurement errors
that are too large to allow us to form strong conclusions. Deeper spectra at
even earlier epochs in combination with analysis techniques based on full
spectral fitting are required to precisely measure the abundance pattern
shortly after the major star-forming phase (z>2). Here we report a measurement
of [Mg/Fe] for a massive quiescent galaxy at z=2.1. With [Mg/Fe]=0.59+/-0.11,
this galaxy is the most Mg-enhanced massive galaxy found so far, having twice
the Mg enhancement of similar-mass galaxies today. The abundance pattern of the
galaxy is consistent with enrichment exclusively by core-collapse supernovae
and with a star-formation timescale of 0.1-0.5 Gyr - characteristics that are
similar to population II stars in the Milky Way. With an average past SFR of
600-3000 Msol/yr, this galaxy was among the most vigorous star-forming galaxies
in the Universe.


title:
Non-standard gravitational waves imply gravitational slip: on the
  difficulty of partially hiding new gravitational degrees of freedom

abstract:
  In many generalized models of gravity, perfect fluids in cosmology give rise
to gravitational slip. Simultaneously, in very broad classes of such models,
the propagation of gravitational waves is altered. We investigate the extent to
which there is a one-to-one relationship between these two properties in three
classes of models with one extra degree of freedom: scalar (Horndeski and
beyond), vector (Einstein-Aether) and tensor (bimetric).
  We prove that in bimetric gravity and Einstein-Aether, it is impossible to
dynamically hide the gravitational slip on all scales whenever the propagation
of gravitational waves is modified. Horndeski models are much more flexible,
but it is nonetheless only possible to hide gravitational slip dynamically when
the action for perturbations is tuned to evolve in time toward a divergent
kinetic term. These results provide an explicit, theoretical argument for the
interpretation of future observations if they disfavoured the presence of
gravitational slip.


title:
Parameter estimation for gravitational-wave bursts with the BayesWave
  pipeline

abstract:
  We provide a comprehensive multi-aspect study on the performance of a
pipeline used by the LIGO-Virgo Collaboration for estimating parameters of
gravitational-wave bursts. We add simulated signals with four different
morphologies (sine-Gaussians, Gaussians, white-noise bursts, and binary black
hole signals) to simulated noise samples representing noise of the two Advanced
LIGO detectors during their first observing run. We recover them with the
BayesWave (BW) pipeline to study its accuracy in sky localization, waveform
reconstruction, and estimation of model-independent waveform parameters. BW
localizes sources with a level of accuracy comparable for all four
morphologies, with the median separation of actual and estimated sky locations
ranging from 25.1$^{\circ}$ to 30.3$^{\circ}$. This is a reasonable accuracy in
the two-detector case, and is comparable to accuracies of other localization
methods studied previously. As BW reconstructs generic transient signals with
sine-Gaussian wavelets, it is unsurprising that BW performs the best in
reconstructing sine-Gaussian and Gaussian waveforms. BW's accuracy in waveform
reconstruction increases steeply with network signal-to-noise ratio (SNR$_{\rm
net}$), reaching a $85\%$ and $95\%$ match between the reconstructed and actual
waveform below SNR$_{\rm net} \approx 20$ and SNR$_{\rm net} \approx 50$,
respectively, for all morphologies. BW's accuracy in estimating central moments
of waveforms is only limited by statistical errors in the frequency domain, and
is affected by systematic errors too in the time domain as BW cannot
reconstruct low-amplitude parts of signals overwhelmed by noise. The figures of
merit we introduce can be used in future characterizations of parameter
estimation pipelines.


title: Multi-Messenger Time Delays from Lensed Gravitational Waves

abstract:
  We investigate the potential of high-energy astrophysical events, from which
both massless and massive signals are detected, to probe fundamental physics.
In particular, we consider how strong gravitational lensing can induce time
delays in multi-messenger signals originating from the same source. Obvious
messenger examples are massless photons and gravitational waves, and massive
neutrinos, although more exotic applications can also be imagined, such as to
massive gravitons or axions. The different propagation times of the massive and
massless particles can, in principle, place bounds on the total neutrino mass
and probe cosmological parameters. Whilst measuring such an effect may pose a
significant experimental challenge, we believe that the `massive time delay'
represents an unexplored fundamental physics phenomenon.


title: Two-point Functions in a Holographic Kondo Model

abstract:
  We develop the formalism of holographic renormalization to compute two-point
functions in a holographic Kondo model. The model describes a
$(0+1)$-dimensional impurity spin of a gauged $SU(N)$ interacting with a
$(1+1)$-dimensional, large-$N$, strongly-coupled Conformal Field Theory (CFT).
We describe the impurity using Abrikosov pseudo-fermions, and define an
$SU(N)$-invariant scalar operator $\mathcal{O}$ built from a pseudo-fermion and
a CFT fermion. At large $N$ the Kondo interaction is of the form
$\mathcal{O}^{\dagger} \mathcal{O}$, which is marginally relevant, and
generates a Renormalization Group (RG) flow at the impurity. A second-order
mean-field phase transition occurs in which $\mathcal{O}$ condenses below a
critical temperature, leading to the Kondo effect, including screening of the
impurity. Via holography, the phase transition is dual to holographic
superconductivity in $(1+1)$-dimensional Anti-de Sitter space. At all
temperatures, spectral functions of $\mathcal{O}$ exhibit a Fano resonance,
characteristic of a continuum of states interacting with an isolated resonance.
In contrast to Fano resonances observed for example in quantum dots, our
continuum and resonance arise from a $(0+1)$-dimensional UV fixed point and RG
flow, respectively. In the low-temperature phase, the resonance comes from a
pole in the Green's function of the form $-i \langle {\cal O} \rangle^2$, which
is characteristic of a Kondo resonance.


title: Interacting Supernovae: Types IIn and Ibn

abstract:
  Supernovae (SNe) that show evidence of strong shock interaction between their
ejecta and pre-existing, slower circumstellar material (CSM) constitute an
interesting, diverse, and still poorly understood category of explosive
transients. The chief reason that they are extremely interesting is because
they tell us that in a subset of stellar deaths, the progenitor star may become
wildly unstable in the years, decades, or centuries before explosion. This is
something that has not been included in standard stellar evolution models, but
may significantly change the end product and yield of that evolution, and
complicates our attempts to map SNe to their progenitors. Another reason they
are interesting is because CSM interaction is an efficient engine for making
bright transients, allowing super-luminous transients to arise from normal SN
explosion energies, and allowing transients of normal SN luminosities to arise
from sub-energetic explosions or low radioactivity yield. CSM interaction
shrouds the fast ejecta in bright shock emission, obscuring our normal view of
the underlying explosion, and the radiation hydrodynamics of the interaction is
challenging to model. The CSM interaction may also be highly non-spherical,
perhaps linked to binary interaction in the progenitor system. In some cases,
these complications make it difficult to definitively tell the difference
between a core-collapse or thermonuclear explosion, or to discern between a
non-terminal eruption, failed SN, or weak SN. Efforts to uncover the physical
parameters of individual events and connections to possible progenitor stars
make this a rapidly evolving topic that continues to challenge paradigms of
stellar evolution.


title:
Topological classification of crystalline insulators through band
  structure combinatorics

abstract:
  We present a method for efficiently enumerating all allowed, topologically
distinct, electronic band structures within a given crystal structure. The
algorithm applies to crystals with broken time-reversal, particle-hole, and
chiral symmetries in any dimension. The presented results match the
mathematical structure underlying the topological classification of these
crystals in terms of K-theory, and therefore elucidate this abstract
mathematical framework from a simple combinatorial perspective. Using a
straightforward counting procedure, we classify the allowed topological phases
in any possible two-dimensional crystal in class A. We also show how the same
procedure can be used to classify the allowed phases for any three-dimensional
space group. Employing these classifications, we study transitions between
topological phases within class A that are driven by band inversions at high
symmetry points in the first Brillouin zone. This enables us to list all
possible types of phase transitions within a given crystal structure, and
identify whether or not they give rise to intermediate Weyl semimetallic
phases.

categories: cond-mat.mes-hall hep-th math-ph math.MP


title: Little String Defects and Bala-Carter Theory

abstract:
  We give a physical realization of the Bala-Carter labels that classify
nilpotent orbits of semi-simple Lie algebras, for the case
$\mathfrak{g}=A,D,E$. We start from type IIB string theory compactified on an
$ADE$ singularity and study the six-dimensional (2,0) $\mathfrak{g}$-type
little string on a Riemann surface with punctures. The defects are introduced
as D-branes wrapping the 2-cycles of the singularity. At low energies, the
little string becomes the (2,0) conformal field theory of type $\mathfrak{g}$.
As an application, we derive the full list of $E_n$ little string defects, and
their Bala-Carter label in the CFT limit. Furthermore, we investigate new
relations between the quiver gauge theory describing the D-brane defects at low
energies, and the weighted Dynkin diagrams of $\mathfrak{g}$. We also give a
physical version of the dimension formula of a nilpotent orbit based on its
weighted Dynkin diagram.


title: Spitzer Photometry of ~1 Million Stars in M31 and 15 Other Galaxies

abstract:
  We present Spitzer IRAC $3.6-8 \mu$m and MIPS $24 \mu$m point-source catalogs
for M $31$ and $15$ other mostly large, star forming galaxies at distances
$\sim3.5-14$ Mpc including M $51$, M $83$, M $101$ and NGC $6946$. These
catalogs contain $\sim1$ million sources including $\sim859,000$ in M 31 and
$\sim116,000$ in the other galaxies. They were created following the procedures
described in Khan et al. (2015) through a combination of point spread function
(PSF) fitting and aperture photometry. These data products constitute a
resource to improve our understanding of the IR-bright ($3.6-24 \mu$m)
point-source populations in crowded extragalactic stellar fields and to plan
observations with the James Webb Space Telescope.


title: Particle Dark Matter Constraints: the Effect of Galactic Uncertainties

abstract:
  Collider, space, and Earth based experiments are now able to probe several
extensions of the Standard Model of particle physics which provide viable dark
matter candidates. Direct and indirect dark matter searches rely on inputs of
astrophysical nature, such as the local dark matter density or the shape of the
dark matter profile in the target in object. The determination of these
quantities is highly affected by astrophysical uncertainties. The latter,
especially those for our own Galaxy, are ill-known, and often not fully
accounted for when analyzing the phenomenology of particle physics models. In
this paper we present a systematic, quantitative estimate of how astrophysical
uncertainties on Galactic quantities (such as the local galactocentric
distance, circular velocity, or the morphology of the stellar disk and bulge)
propagate to the determination of the phenomenology of particle physics models,
thus eventually affecting the determination of new physics parameters. We
present results in the context of two specific extensions of the Standard Model
(the Singlet Scalar and the Inert Doublet) that we adopt as case studies for
their simplicity in illustrating the magnitude and impact of such uncertainties
on the parameter space of the particle physics model itself. Our findings point
toward very relevant effects of current Galactic uncertainties on the
determination of particle physics parameters, and urge a systematic estimate of
such uncertainties in more complex scenarios, in order to achieve constraints
on the determination of new physics that realistically include all known
uncertainties.


title:
Endurance of SN 2005ip after a decade: X-rays, radio, and H-alpha like
  SN 1988Z require long-lived pre-supernova mass loss

abstract:
  SN2005ip was a TypeIIn event notable for its sustained strong interaction
with circumstellar material (CSM), coronal emission lines, and IR excess,
interpreted as shock interaction with the very dense and clumpy wind of an
extreme red supergiant. We present a series of late-time spectra of SN2005ip
and a first radio detection of this SN, plus late-time X-rays, all of which
indicate that its CSM interaction is still strong a decade post-explosion. We
also present and discuss new spectra of geriatric SNe with continued CSM
interaction: SN1988Z, SN1993J, and SN1998S. From 3-10 yr post-explosion,
SN2005ip's H-alpha luminosity and other observed characteristics were nearly
identical to those of the radio-luminous SN1988Z, and much more luminous than
SNe1993J and 1998S. At 10 yr after explosion, SN2005ip showed a drop in
H$\alpha$ luminosity, followed by a quick resurgence over several months. We
interpret this variability as ejecta crashing into a dense shell located at
around 0.05 pc from the star, which may be the same shell that caused the IR
echo at earlier epochs. The extreme H-alpha luminosities in SN2005ip and
SN1988Z are still dominated by the forward shock at 10 yr post-explosion,
whereas SN1993J and SN1998S are dominated by the reverse shock at a similar
age. Continuous strong CSM interaction in SNe~2005ip and 1988Z is indicative of
enhanced mass loss for about 1e3 yr before core collapse, longer than Ne, O, or
Si burning phases. Instead, the episodic mass loss must extend back through C
burning and perhaps even part of He burning.


title:
Probability distribution of the entanglement across a cut at an
  infinite-randomness fixed point

abstract:
  We calculate the probability distribution of entanglement entropy S across a
cut of a finite one dimensional spin chain of length L at an infinite
randomness fixed point using Fisher's strong randomness renormalization group
(RG). Using the random transverse-field Ising model as an example, the
distribution is shown to take the form $p(S|L) \sim L^{-\psi(k)}$, where $k = S
/ \log [L/L_0]$, the large deviation function $\psi(k)$ is found explicitly,
and $L_0$ is a nonuniversal microscopic length. We discuss the implications of
such a distribution on numerical techniques that rely on entanglement, such as
matrix product state (MPS) based techniques. Our results are verified with
numerical RG simulations, as well as the actual entanglement entropy
distribution for the random transverse-field Ising model which we calculate for
large L via a mapping to Majorana fermions.


title:
Excited State Quantum Phase Transitions Studied from a Non-Hermitian
  Perspective

abstract:
  A main distinguishing feature of non-Hermitian quantum mechanics is the
presence of exceptional points (EPs). They correspond to the coalescence of two
energy levels and their respective eigenvectors. Here, we use the
Lipkin-Meshkov-Glick (LMG) model as a testbed to explore the strong connection
between EPs and the onset of excited state quantum phase transitions (ESQPTs).
We show that for finite systems, the exact degeneracies (EPs) obtained with the
non-Hermitian LMG Hamiltonian continued into the complex plane are directly
linked with the avoided crossings that characterize the ESQPTs for the real
(physical) LMG Hamiltonian. The values of the complex control parameter
$\alpha$ that lead to the EPs approach the real axis as the system size
$N\rightarrow \infty$. This happens for both, the EPs that are close to the
separatrix that marks the ESQPT and also for those that are far away, although
in the latter case, the rate the imaginary part of $\alpha$ reduces to zero as
$N$ increases is smaller. With the method of Pad\'e approximants, we can
extract the critical value of $\alpha$.


title: Recrudescence of massive fermion production by oscillons

abstract:
  In this letter we bring together the physics of preheating, following a
period of inflation, and the dynamics of non-topological solitons, namely
oscillons. We show that the oscillating condensate that makes up an oscillon
can be an efficient engine for producing heavy fermions, just as a homogeneous
condensate is known for doing the same. This then allows heavy fermions to be
produced when the energy scale of the Universe has dropped below the scale
naturally associated to the fermions.


title: A Black Hole Mass Determination for the Compact Galaxy Mrk 1216

abstract:
  Mrk 1216 is a nearby, early-type galaxy with a small effective radius of 2.8
kpc and a large stellar velocity dispersion of 308 km/s for its K-band
luminosity of 1.4x10^11 L_sun. Using integral-field spectroscopy assisted by
adaptive optics from Gemini North, we measure spatially resolved stellar
kinematics within ~450 pc of the galaxy nucleus. The galaxy exhibits regular
rotation with velocities of \pm 180 km/s and a sharply peaked velocity
dispersion profile that reaches 425 km/s at the center. We fit axisymmetric,
orbit-based dynamical models to the combination of these high angular
resolution kinematics, large-scale kinematics extending to roughly three
effective radii, and Hubble Space Telescope imaging, resulting in a constraint
of the mass of the central black hole in Mrk 1216. After exploring several
possible sources of systematics that commonly affect stellar-dynamical black
hole mass measurements, we find a black hole mass of (4.9\pm1.7)x10^9 M_sun and
a H-band stellar mass-to-light ratio of 1.3\pm0.4 M_sun/L_sun (1-sigma
uncertainties). Mrk 1216 is consistent with the local black hole mass - stellar
velocity dispersion relation, but is a factor of ~5-10 larger than expectations
from the black hole mass - bulge luminosity and black hole mass - bulge mass
correlations when conservatively using the galaxy's total luminosity or stellar
mass. This behavior is quite similar to the extensively studied compact galaxy
NGC 1277. Resembling the z~2 quiescent galaxies, Mrk 1216 may be a passively
evolved descendant, and perhaps reflects a previous era when galaxies contained
over-massive black holes relative to their bulge luminosities/masses, and the
growth of host galaxies had yet to catch up.


title: The impact of non-ideal magnetohydrodynamics on binary star formation

abstract:
  We investigate the effect of non-ideal magnetohydrodynamics (MHD) on the
formation of binary stars using a suite of three-dimensional smoothed particle
magnetohydrodynamics simulations of the gravitational collapse of one solar
mass, rotating, perturbed molecular cloud cores. Alongside the role of Ohmic
resistivity, ambipolar diffusion and the Hall effect, we also examine the
effects of magnetic field strength, orientation and amplitude of the density
perturbation. When modelling sub-critical cores, ideal MHD models do not
collapse whereas non-ideal MHD models collapse to form single protostars. In
super-critical ideal MHD models, increasing the magnetic field strength or
decreasing the initial density perturbation amplitude decreases the initial
binary separation. Strong magnetic fields initially perpendicular to the
rotation axis suppress the formation of binaries and yield discs with magnetic
fields ~10 times stronger than if the magnetic field was initially aligned with
the rotation axis. When non-ideal MHD is included, the resulting discs are
larger and more massive, and the binary forms on a wider orbit. Small
differences in the super-critical cores caused by non-ideal MHD effects are
amplified by the binary interaction near periastron. Overall, the non-ideal
effects have only a small impact on binary formation and early evolution, with
the initial conditions playing the dominant role.


title:
Recovering interstellar gas properties with HI spectral lines: A
  comparison between synthetic spectra and 21-SPONGE

abstract:
  We analyze synthetic neutral hydrogen (HI) absorption and emission spectral
lines from a high- resolution, three-dimensional hydrodynamical simulation to
quantify how well observational methods recover the physical properties of
interstellar gas. We present a new method for uniformly decomposing HI spectral
lines and estimating the properties of associated gas using the Autonomous
Gaussian Decomposition (AGD) algorithm. We find that Hi spectral lines recover
physical structures in the simulation with excellent completeness at high
Galactic latitude, and this completeness declines with decreasing latitude due
to strong velocity-blending of spectral lines. The temperature and column
density inferred from our decomposition and radiative transfer method agree
with the simulated values within a factor of < 2 for the majority of gas
structures. We next compare synthetic spectra with observations from the
21-SPONGE survey at the Karl G. Jansky Very Large Array using AGD. We find more
components per line of sight in 21-SPONGE than in synthetic spectra, which
reflects insufficient simulated gas scale heights and the limitations of local
box simulations. In addition, we find a significant population of low-optical
depth, broad absorption components in the synthetic data which are not seen in
21-SPONGE. This population is not obvious in integrated or per-channel
diagnostics, and reflects the benefit of studying velocity-resolved components.
The discrepant components correspond to the highest spin temperatures (1000 <
Ts < 4000 K), which are not seen in 21-SPONGE despite sufficient observational
sensitivity. We demonstrate that our analysis method is a powerful tool for
diagnosing neutral ISM conditions, and future work is needed to improve
observational statistics and implementation of simulated physics.


title:
Cross-correlation of galaxies and galaxy clusters in the Sloan Digital
  Sky Survey and the importance of non-Poissonian shot noise

abstract:
  We present measurements of angular cross power spectra between galaxies and
optically-selected galaxy clusters in the final photometric sample of the Sloan
Digital Sky Survey (SDSS). We measure the auto- and cross-correlations between
galaxy and cluster samples, from which we extract the effective biases and
study the shot noise properties. We model the non-Poissonian shot noise by
introducing an effective number density of tracers and fit for this quantity.
We find that we can only describe the cross-correlation of galaxies and galaxy
clusters, as well as the auto-correlation of galaxy clusters, on the relevant
scales using a non-Poissonian shot noise contribution.
  The values of effective bias we finally measure for a volume-limited sample
are $b_{cc}=4.09 \pm 0.47$ for the cluster auto-correlation and $b_{gc}=2.15
\pm 0.09$ for the galaxy-cluster cross-correlation. We find that these results
are consistent with expectations from the auto-correlations of galaxies and
clusters and are in good agreement with previous studies. The main result is
two-fold: firstly we provide a measurement of the cross-correlation of galaxies
and clusters, which can be used for further cosmological analysis, and secondly
we describe an effective treatment of the shot noise.


title:
PTF1 J082340.04+081936.5: A hot subdwarf B star with a low mass white
  dwarf companion in an 87 minute orbit

abstract:
  We present the discovery of the hot subdwarf B star (sdB) binary PTF1
J082340.04+081936.5. The system has an orbital period P$_{\rm orb}=87.49668(1)$
min (0.060761584(10) days), making it the second-most compact sdB binary known.
The lightcurve shows ellipsoidal variations. Under the assumption that the sdB
primary is synchronized with the orbit, we find a mass $M_{\rm
sdB}=0.45^{+0.09}_{-0.07}$ M$_\odot$, a companion white dwarf mass $M_{\rm
WD}=0.46^{+0.12}_{-0.09}$ M$_\odot$ and a mass ratio $q = \frac{M_{\rm
WD}}{M_{\rm sdB}}=1.03^{+0.10}_{-0.08}$.
  The future evolution was calculated using the MESA stellar evolution code.
Adopting a canonical sdB mass of $M_{\rm sdB}=0.47$ M$_\odot$, we find that the
sdB still burns helium at the time it will fill its Roche lobe if the orbital
period was less than 106 min at the exit from the last common envelope phase.
For longer common envelope exit periods the sdB will have stopped burning
helium and turned into a C/O white dwarf at the time of contact. Comparing the
spectroscopically derived log(g) and $T_{\rm eff}$ with our MESA models, we
find that an sdB model with a hydrogen envelope mass of $5\times10^{-4}
M_\odot$ matches the measurements at a post-common envelope age of 94 Myr,
corresponding to a post-common envelope orbital period of 109 min which is
close to the limit to start accretion while the sdB is still burning helium.


title:
Energy equality for the 3D critical convective Brinkman-Forchheimer
  equations

abstract:
  In this paper we give a simple proof of the existence of global-in-time
smooth solutions for the convective Brinkman-Forchheimer equations (also called
in the literature the tamed Navier-Stokes equations) $$ \partial_tu -\mu\Delta
u + (u \cdot \nabla)u + \nabla p + \alpha u + \beta|u|^{r - 1}u = 0 $$ on a
$3$D periodic domain, for values of the absorption exponent $r$ larger than
$3$. Furthermore, we prove that global, regular solutions exist also for the
critical value of exponent $r = 3$, provided that the coefficients satisfy the
relation $4\mu\beta \geq 1$. Additionally, we show that in the critical case
every weak solution verifies the energy equality and hence is continuous into
the phase space $L^2$. As an application of this result we prove the existence
of a strong global attractor, using the theory of evolutionary systems
developed by Cheskidov.


title:
The action principle and the supersymmetrisation of Chern-Simons terms
  in eleven-dimensional supergravity

abstract:
  We develop computational tools for calculating supersymmetric higher-order
derivative corrections to eleven-dimensional supergravity using the action
principle approach. We show that, provided the superspace Bianchi identities
admit a perturbative solution in the derivative expansion, there are at least
two independent superinvariants at the eight-derivative order of
eleven-dimensional supergravity. Assuming the twelve-superforms associated to
certain anomalous Chern-Simons terms are Weil-trivial, there will be a third
independent superinvariant at this order. Under certain conditions, at least
two superinvariants will survive to all orders in the derivative expansion.
However only one of them will be present in the quantum theory: the
supersymmetrization of the Chern-Simons terms of eleven dimensional
supergravity required for the cancellation of the M5-brane gravitational
anomaly by inflow. This superinvariant can be shown to be unique at the
eight-derivative order, assuming it is quartic in the fields. On the other
hand, a necessary condition for the superinvariant to be quartic is the
exactness, in tau-cohomology, of X0,8 -the purely spinorial component of the
eight-superform related by descent to the M5-brane anomaly polynomial. In that
case it can also be shown that the solution of the Weil-triviality condition of
the corresponding twelve-form, which is a prerequisite for the explicit
construction of the superinvariant, is guaranteed to exist. We prove that
certain highly non-trivial necessary conditions for the tau-exactness of X0,8
are satisfied. Moreover any potential superinvariant associated to anomalous
Chern-Simons terms at the eight-derivative order must necessarily contain terms
cubic or lower in the fields.


title: Manifolds with many hyperbolic planes

abstract:
  We construct examples of complete Riemannian manifolds having the property
that every geodesic lies in a totally geodesic hyperbolic plane. Despite the
abundance of totally geodesic hyperbolic planes, these examples are not locally
homogenous.


title: Robust Calibration of Radio Interferometers in Non-Gaussian Environment

abstract:
  The development of new phased array systems in radio astronomy, as the low
frequency array (LOFAR) and the square kilometre array (SKA), formed of a large
number of small and flexible elementary antennas, has led to significant
challenges. Among them, model calibration is a crucial step in order to provide
accurate and thus meaningful images and requires the estimation of all the
perturbation effects introduced along the signal propagation path, for a
specific source direction and antenna position. Usually, it is common to
perform model calibration using the a priori knowledge regarding a small number
of known strong calibrator sources but under the assumption of Gaussianity of
the noise. Nevertheless, observations in the context of radio astronomy are
known to be affected by the presence of outliers which are due to several
causes, e.g., weak non-calibrator sources or man made radio frequency
interferences. Consequently, the classical Gaussian noise assumption is
violated leading to severe degradation in performances. In order to take into
account the outlier effects, we assume that the noise follows a spherically
invariant random distribution. Based on this modeling, a robust calibration
algorithm is presented in this paper. More precisely, this new scheme is based
on the design of an iterative relaxed concentrated maximum likelihood
estimation procedure which allows to obtain closed-form expressions for the
unknown parameters with a reasonable computational cost. This is of importance
as the number of estimated parameters depends on the number of antenna
elements, which is large for the new generation of radio interferometers.
Numerical simulations reveal that the proposed algorithm outperforms the
state-of-the-art calibration techniques.


title: Impossible Inference in Econometrics: Theory and Applications

abstract:
  This paper studies models in which hypothesis tests have trivial power, that
is, power smaller than size. This testing impossibility, or impossibility type
A, arises when any alternative is not distinguishable from the null. We also
study settings in which it is impossible to have almost surely bounded
confidence sets for a parameter of interest. This second type of impossibility
(type B) occurs under a condition weaker than the condition for type A
impossibility: the parameter of interest must be nearly unidentified. Our
theoretical framework connects many existing publications on impossible
inference that rely on different notions of topologies to show models are not
distinguishable or nearly unidentified. We also derive both types of
impossibility using the weak topology induced by convergence in distribution.
Impossibility in the weak topology is often easier to prove, it is applicable
for many widely-used tests, and it is useful for robust hypothesis testing. We
conclude by demonstrating impossible inference in multiple economic
applications of models with discontinuity and time-series models.

categories: math.ST q-fin.EC stat.AP stat.ME stat.TH


title: Lipschitz Embeddings of Metric Spaces into $c_0$

abstract:
  Let $M$ be a separable metric space. We say that $f=(f_n):M\to c_0$ is a
good-$\lambda$-embedding if, whenever $x,y\in M$, $x\ne y$ implies
$d(x,y)\le\Vert f(x)-f(y)\Vert$ and, for each $n$, $Lip(f_n)<\lambda$, where
$Lip(f_n)$ denotes the Lipschitz constant of $f_n$. We prove that there exists
a good-$\lambda$-embedding from $M$ into $c_0$ if and only if $M$ satisfies an
internal property called $\pi(\lambda)$. As a consequence, we obtain that for
any separable metric space $M$, there exists a good-$2$-embedding from $M$ into
$c_0$. These statements slightly extend former results obtained by N. Kalton
and G. Lancien, with simplified proofs.


title: On homotopy Lie bialgebroids

abstract:
  A well-known result of A. Vaintrob characterizes Lie algebroids and their
morphisms in terms of homological vector fields on supermanifolds. We give an
interpretation of Lie bialgebroids and their morphisms in terms of odd
symplectic dg-manifolds, building on the approach of D. Roytenberg. This
extends naturally to the homotopy Lie case and leads to the notion of
$L_\infty$-bialgebroids and $L_\infty$-morphisms between them.


title: Selective sensitivity in Kerr microscopy

abstract:
  A new technique for contrast separation in wide-field magneto-optical Kerr
microscopy is introduced. Utilizing the light from eight light emitting diodes,
guided to the microscope by glass fibers and being switched synchronously with
the camera exposure, domain images with orthogonal in-plane sensitivity can be
displayed simultaneously at real-time and images with pure in-plane or polar
contrast can be obtained. The benefit of this new method of contrast separation
is demonstrated for permalloy films, a NdFeB sinter magnet, and a cobalt
crystal. Moreover, the new technique is shown to strongly enhance the
sensitivity of Kerr microscopy by eliminating parasitic contrast contributions
occurring in conventional setups. A doubling of the in-plane domain contrast
and a sensitivity to Kerr rotations as low as 0.6~mdeg is demonstrated


title:
Measurement Of Energy Resolution For TES Microcalorimeter With Optical
  Pulses

abstract:
  Energy resolution is an important figure of merit for TES microcalorimeter.
We propose a laser system to measure the energy resolution of TES
microcalorimeter with a 1550 nm laser source. Compared to method that
characterizes the performance by irradiating the detector using X-ray photons
from a radioactive source placed inside the refrigerator, our system is safer
and more convenient. The feasibility of this system has been demonstrated in
the measurement of an Al/Ti bilayer TES microcalorimeter. In this experiment,
the tested detector showed a energy resolution of 72 eV in the energy range
from 0.2 keV to 0.9 keV


title:
Upper Limits on the Stochastic Gravitational-Wave Background from
  Advanced LIGO's First Observing Run

abstract:
  A wide variety of astrophysical and cosmological sources are expected to
contribute to a stochastic gravitational-wave background. Following the
observations of GW150914 and GW151226, the rate and mass of coalescing binary
black holes appear to be greater than many previous expectations. As a result,
the stochastic background from unresolved compact binary coalescences is
expected to be particularly loud. We perform a search for the isotropic
stochastic gravitational-wave background using data from Advanced LIGO's first
observing run. The data display no evidence of a stochastic gravitational-wave
signal. We constrain the dimensionless energy density of gravitational waves to
be $\Omega_0<1.7\times 10^{-7}$ with 95% confidence, assuming a flat energy
density spectrum in the most sensitive part of the LIGO band (20-86 Hz). This
is a factor of ~33 times more sensitive than previous measurements. We also
constrain arbitrary power-law spectra. Finally, we investigate the implications
of this search for the background of binary black holes using an astrophysical
model for the background.


title:
Directional limits on persistent gravitational waves from Advanced
  LIGO's first observing run

abstract:
  We employ gravitational-wave radiometry to map the gravitational waves
stochastic background expected from a variety of contributing mechanisms and
test the assumption of isotropy using data from Advanced LIGO's first observing
run. We also search for persistent gravitational waves from point sources with
only minimal assumptions over the 20 - 1726 Hz frequency band. Finding no
evidence of gravitational waves from either point sources or a stochastic
background, we set limits at 90% confidence. For broadband point sources, we
report upper limits on the gravitational wave energy flux per unit frequency in
the range $F_{\alpha,\Theta}(f) < (0.1 - 56) \times 10^{-8}$ erg cm$^{-2}$
s$^{-1}$ Hz$^{-1}$ (f/25 Hz)$^{\alpha-1}$ depending on the sky location
$\Theta$ and the spectral power index $\alpha$. For extended sources, we report
upper limits on the fractional gravitational wave energy density required to
close the Universe of $\Omega(f,\Theta) < (0.39-7.6) \times 10^{-8}$ sr$^{-1}$
(f/25 Hz)$^\alpha$ depending on $\Theta$ and $\alpha$. Directed searches for
narrowband gravitational waves from astrophysically interesting objects
(Scorpius X-1, Supernova 1987 A, and the Galactic Center) yield median
frequency-dependent limits on strain amplitude of $h_0 <$ (6.7, 5.5, and 7.0)
$\times 10^{-25}$ respectively, at the most sensitive detector frequencies
between 130 - 175 Hz. This represents a mean improvement of a factor of 2
across the band compared to previous searches of this kind for these sky
locations, considering the different quantities of strain constrained in each
case.

categories: gr-qc astro-ph.CO astro-ph.HE astro-ph.IM


title:
Laser-induced dissociative ionization of H$_{2}$ from the near-infrared
  to the mid-infrared regime

abstract:
  We apply the Monte Carlo Wave Packet (MCWP) approach to investigate the
kinetic energy release (KER) spectra of the protons following double ionization
in H$_{2}$ when interacting with laser pulses with central wavelengths ranging
from the near-IR (800 nm) to the mid-IR (6400 nm) regions and with durations of
3-21 laser cycles. We uncover the physical origins of the peaks in the nuclear
KER spectra and ascribe them to mechanisms such as ionization following a
resonant dipole transition, charge-resonance-enhanced ionization (CREI) and
ionization in the dissociative limit of large internuclear distances. For
relatively large pulse durations, i.e., for 15 or more laser cycles at 3200 nm
and 10 or more at 6400 nm, it is possible for the nuclear wave packet in
H$_{2}^{+}$ to reach very large separations. Ionization of this part of the
wave packet results in peaks in the KER spectra with very low energies. These
peaks give direct information about the dissociative energy in the
$2p\sigma_{u}$ potential energy curve of H$_{2}^{+}$ at the one- and
three-photon resonances between the $2p\sigma_{u}$ and $1s\sigma_{g}$ curves in
H$_{2}^{+}$. With the MCWP approach, we perform a trajectory analysis of the
contributions to the KER peaks and identify the dominant ionization pathways.
Finally, we consider a pump-probe scheme by applying two delayed pulses to
track the nuclear dynamics in a time-resolved setting. Low-energy peaks appear
for large delays and these are used to obtain the $2p\sigma_{u}$ dissociative
energy values at the one-photon resonance between the $2p\sigma_{u}$ and
$1s\sigma_{g}$ curves in H$_{2}^{+}$ for different wavelengths.


title: Approximation by $C^1$ Splines on Piecewise Conic Domains

abstract:
  We develop a Hermite interpolation scheme and prove error bounds for $C^1$
bivariate piecewise polynomial spaces of Argyris type vanishing on the boundary
of curved domains enclosed by piecewise conics.


title:
Global hypoellipticity for a class of pseudo-differential operators on
  the torus

abstract:
  We show that an obstruction of number-theoretical nature appears as a
necessary condition for the global hypoellipticity of the pseudo-differential
operator $L=D_t+(a+ib)(t)P(D_x)$ on $\mathbb{T}^1_t\times\mathbb{T}_x^{N}$.
This condition is also sufficient when the symbol $p(\xi)$ of $P(D_x)$ has at
most logarithmic growth. If $p(\xi)$ has super-logarithmic growth, we show that
the global hypoellipticity of $L$ depends on the change of sign of certain
interactions of the coefficients with the symbol $p(\xi).$ Moreover, the
interplay between the order of vanishing of coefficients with the order of
growth of $p(\xi)$ plays a crucial role in the global hypoellipticity of $L$.
We also describe completely the global hypoellipticity of $L$ in the case where
$P(D_x)$ is positively homogeneous. Additionally, we explore the influence of
irrational approximations of a real number in the global hypoellipticity.


title: Approximate Modularity Revisited

abstract:
  Set functions with convenient properties (such as submodularity) appear in
application areas of current interest, such as algorithmic game theory, and
allow for improved optimization algorithms. It is natural to ask (e.g., in the
context of data driven optimization) how robust such properties are, and
whether small deviations from them can be tolerated. We consider two such
questions in the important special case of linear set functions.
  One question that we address is whether any set function that approximately
satisfies the modularity equation (linear functions satisfy the modularity
equation exactly) is close to a linear function. The answer to this is positive
(in a precise formal sense) as shown by Kalton and Roberts [1983] (and further
improved by Bondarenko, Prymak, and Radchenko [2013]). We revisit their proof
idea that is based on expander graphs, and provide significantly stronger upper
bounds by combining it with new techniques. Furthermore, we provide improved
lower bounds for this problem.
  Another question that we address is that of how to learn a linear function
$h$ that is close to an approximately linear function $f$, while querying the
value of $f$ on only a small number of sets. We present a deterministic
algorithm that makes only linearly many (in the number of items) nonadaptive
queries, by this improving over a previous algorithm of Chierichetti, Das,
Dasgupta and Kumar [2015] that is randomized and makes more than a quadratic
number of queries. Our learning algorithm is based on a Hadamard transform.


title:
Elusive preferred hosts or nucleic acid level selection? A commentary
  on: Evolutionary interpretations of mycobacteriophage biodiversity and
  host-range through the analysis of codon usage bias (Esposito et al. 2016)

abstract:
  While confirming the long held view that viruses do not closely imitate the
use of their host's codon catalogue, Esposito and coworkers nevertheless
consider it surprising that, despite having the ability to infect the same
host, many mycobacteriophages share little or no genetic similarity (i.e.
similarity in their GC contents and codon utilization patterns). Arguing
correctly that efficient translation of a phage's proteins within a host is
likely to be optimized by the phage's ability to match the host's codon usage
pattern, it is concluded that the preferred host of many mycobacteriophages is
not Mycobacterium smegmatis, despite their having been isolated on that
organism. Thus, a virus and its elusive preferred hosts would have had similar
GC percentages and codon usages, but the same virus could still infect a
less-preferred host (Mycobacterium smegmatis), where the virus-host similarity
would be less evident. However, there is another evolutionary interpretation.


title:
Matter bounce cosmology with a generalized single field: non-Gaussianity
  and an extended no-go theorem

abstract:
  We extend the matter bounce scenario to a more general theory in which the
background dynamics and cosmological perturbations are generated by a
$k$-essence scalar field with an arbitrary sound speed. When the sound speed is
small, the curvature perturbation is enhanced, and the tensor-to-scalar ratio,
which is excessively large in the original model, can be sufficiently
suppressed to be consistent with observational bounds. Then, we study the
primordial three-point correlation function generated during the
matter-dominated contraction stage and find that it only depends on the sound
speed parameter. Similar to the canonical case, the shape of the bispectrum is
mainly dominated by a local form, though for some specific sound speed values a
new shape emerges and the scaling behaviour changes. Meanwhile, a small sound
speed also results in a large amplitude of non-Gaussianities, which is
disfavored by current observations. As a result, it does not seem possible to
suppress the tensor-to-scalar ratio without amplifying the production of
non-Gaussianities beyond current observational constraints (and vice versa).
This suggests an extension of the previously conjectured no-go theorem in
single field nonsingular matter bounce cosmologies, which rules out a large
class of models. However, the non-Gaussianity results remain as a
distinguishable signature of matter bounce cosmology and have the potential to
be detected by observations in the near future.


title:
Stability Analysis of Some Reconstructed Cosmological Models in
  $f(\mathcal{G},T)$ Gravity

abstract:
  The aim of this paper is to reconstruct and analyze the stability of some
cosmological models against linear perturbations in $f(\mathcal{G},T)$ gravity
($\mathcal{G}$ and $T$ represent the Gauss-Bonnet invariant and trace of the
energy-momentum tensor, respectively). We formulate the field equations for
both general as well as particular cases in the context of isotropic and
homogeneous universe model. We reproduce the cosmic evolution corresponding to
de Sitter universe, power-law solutions and phantom/non-phantom eras in this
theory using reconstruction technique. Finally, we study stability analysis of
de Sitter as well as power-law solutions through linear perturbations.


title: Quantum regime of laser-matter interactions at extreme intensities

abstract:
  A survey of physical parameters and of a ladder of various regimes of
laser-matter interactions at extreme intensities is given. Special emphases is
made on three selected topics: (i) qualitative derivation of the scalings for
probability rates of the basic processes; (ii) self-sustained cascades (which
may dominate at the intensity levels attainable with next generation laser
facilities); and (iii) possibility of breaking down the Intense Field QED
approach for ultrarelativistic electrons and high-energy photons at certain
intensity level.


title: Localizing High-Lying Rydberg Wave Packets with Two-Color Laser Fields

abstract:
  We demonstrate control over the localization of high-lying Rydberg wave
packets in argon atoms with phase-locked orthogonally polarized two-color (OTC)
laser fields. With a reaction microscope, we measured ionization signals of
high-lying Rydberg states induced by a weak dc field and black-body radiation
as a function of the relative phase between the two-color fields. We find that
the dc-field ionization yields of high-lying Rydberg argon atoms oscillate with
the relative two-color phase with a period of $2\pi$ while the photoionization
signal by black-body radiation shows a period of $\pi$. These observations are
a clear signature of the asymmetric localization of electrons recaptured into
high-lying Rydberg states after conclusion of the laser pulse and are supported
by a semiclassical simulation of argon-OTC laser interaction. Our findings thus
open an effective pathway to control the localization of high-lying Rydberg
wave packets.


title: On the non-minimal character of the SMEFT

abstract:
  When integrating out unknown new physics sectors, what is the minimal
character of the Standard Model Effective Field Theory (SMEFT) that can result?
In this paper we focus on a particular aspect of this question: "How can one
obtain only one dimension six operator in the SMEFT from a consistent tree
level matching onto an unknown new physics sector?" We show why this requires
conditions on the ultraviolet field content that do not indicate a stand alone
ultraviolet complete scenario. Further, we demonstrate how a dynamical origin
of the ultraviolet scales assumed to exist in order to generate the masses of
the heavy states integrated out generically induces more operators. Therefore,
our analysis indicates that the infrared limit captured from a new sector in
consistent matchings induces multiple operators in the SMEFT quite generically.
Global data analyses in the SMEFT can and should accommodate this fact.


title:
Bifurcations of relative periodic orbits in NLS/GP with a triple-well
  potential

abstract:
  The nonlinear Schr\"odinger/Gross-Pitaevskii (NLS/GP) equation is considered
in the presence of three equally-spaced potentials. The problem is reduced to a
finite-dimensional Hamiltonian system by a Galerkin truncation. Families of
oscillatory orbits are sought in the neighborhoods of the system's nine
branches of standing wave solutions. Normal forms are computed in the
neighborhood of these branches' various Hamiltonian Hopf and saddle-node
bifurcations, showing how the oscillatory orbits change as a parameter is
increased. Numerical experiments show agreement between normal form theory and
numerical solutions to the reduced system and NLS/GP near the Hamiltonian Hopf
bifurcations and some subtle disagreements near the saddle-node bifurcations
due to exponentially small terms in the asymptotics.


title:
Non-minimal Coupling of Torsion-matter Satisfying Null Energy Condition
  for Wormhole Solutions

abstract:
  We explore wormhole solutions in a non-minimal torsion-matter coupled gravity
by taking an explicit non-minimal coupling between the matter Lagrangian
density and an arbitrary function of torsion scalar. This coupling depicts the
transfer of energy and momentum between matter and torsion scalar terms. The
violation of null energy condition occurred through effective energy-momentum
tensor incorporating the torsion-matter non-minimal coupling while normal
matter is responsible for supporting the respective wormhole geometries. We
consider energy density in the form of non-monotonically decreasing function
along with two types of models. First model is analogous to curvature-matter
coupling scenario, that is, torsion scalar with $T$-matter coupling while the
second one involves a quadratic torsion term. In both cases, we obtain wormhole
solutions satisfying null energy condition. Also, we find that the increasing
value of coupling constant minimizes or vanishes the violation of null energy
condition through matter.


title:
Photon pair generation in hydrogenated amorphous silicon microring
  resonators

abstract:
  We generate photon pairs in a-Si:H microrings using a CW pump, and find the
Kerr coefficient of a-Si:H to be $3.73 \pm 0.25 \times 10^{-17}m^2/W$. By
measuring the Q factor with coupled power we find that the loss in the a-Si:H
micro-rings scales linearly with power, and therefore cannot originate from two
photon absorption. Theoretically comparing a-Si:H and c-Si micro-ring pair
sources, we show that the high Kerr coefficient of this sample of a-Si:H is
best utilized for microrings with Q factors below $10^3$, but that for higher Q
factor devices the photon pair rate is greatly suppressed due to the first
order loss.


title: Voltage Uncertainties in the Presence of Photovoltaic Systems

abstract:
  With the rising demand for solar energy installation, there is a pressing
need for utilities to regulate the voltages at the distribution level. In grids
with high penetration of photovoltaic (PV) systems, voltage fluctuations can
occur at the distribution systems, resulting in inverter tripping and
insufficient power to meet the load. We present a linear model for voltage rise
versus PV output power. This model can be used to study the effect of
increasing PV system capacities on distribution system voltages. It is observed
that voltage fluctuations have greater correlation with the location of the PV
systems on the grid than with the PV system capacities, i.e., more randomness
and disorder in the behavior of voltage occurs with PV systems with larger line
impedance.


title:
Impact of Grid Impedance Variations on Harmonic Emission of
  Grid-Connected Inverters

abstract:
  This paper addresses harmonic magnification due to resonance circuits
resulting from interaction between uncertain grid impedance and converter. The
source of harmonic may be either the grid or inverter. It is demonstrated that
unknown and unpredictable grid impedance may result in variable resonance
frequency, which challenges robust design of LCL filter of inverter.


title: Charged-particle detection efficiencies of close-packed CsI arrays

abstract:
  Detector efficiency determination is essential to correct the measured yields
and extract reliable cross sections of particles emitted in nuclear reactions.
We investigate the efficiencies for measuring the full energies of light
charged particle in arrays of CsI crystals employed in particle detection
arrays such as HiRA, LASSA and MUST2. We perform these simulations with a
GEANT4 Monte Carlo transport code implemented in the NPTool framework. Both
Coulomb multiple scattering and nuclear reactions within the crystal can
significantly reduce the efficiency of detecting the full energy of high energy
particles. The calculated efficiencies decrease exponentially as a function of
the range of the particle and are quite similar for both the hydrogen ($p, d,
t$) and helium ($^3$He, $\alpha$) isotopes. The use of a close-packed array
introduces significant position dependent efficiency losses at the interior
boundaries between crystals that need to be considered in the design of an
array and in the efficiency corrections of measured energy spectra.


title:
RCSED - A Value-Added Reference Catalog of Spectral Energy Distributions
  of 800,299 Galaxies in 11 Ultraviolet, Optical, and Near-Infrared Bands:
  Morphologies, Colors, Ionized Gas and Stellar Populations Properties

abstract:
  We present RCSED, the value-added Reference Catalog of Spectral Energy
Distributions of galaxies, which contains homogenized spectrophotometric data
for 800,299 low and intermediate redshift galaxies (0.007<z<0.6) selected from
the Sloan Digital Sky Survey spectroscopic sample. Accessible from the Virtual
Observatory (VO) and complemented with detailed information on galaxy
properties obtained with the state-of-the-art data analysis, RCSED enables
direct studies of galaxy formation and evolution during the last 5Gyr. We
provide tabulated color transformations for galaxies of different morphologies
and luminosities and analytic expressions for the red sequence shape in
different colors. RCSED comprises integrated k-corrected photometry in up-to 11
ultraviolet, optical, and near-infrared bands published by the GALEX, SDSS, and
UKIDSS wide-field imaging surveys; results of the stellar population fitting of
SDSS spectra including best-fitting templates, velocity dispersions,
parameterized star formation histories, and stellar metallicities computed for
instantaneous starburst and exponentially declining star formation models;
parametric and non-parametric emission line fluxes and profiles; and gas phase
metallicities. We link RCSED to the Galaxy Zoo morphological classification and
galaxy bulge+disk decomposition results by Simard et al. We construct the
color-magnitude, Faber-Jackson, mass-metallicity relations, compare them with
the literature and discuss systematic errors of galaxy properties presented in
our catalog. RCSED is accessible from the project web-site and via VO simple
spectrum access and table access services using VO compliant applications. We
describe several SQL query examples against the database. Finally, we briefly
discuss existing and future scientific applications of RCSED and prospectives
for the catalog extension to higher redshifts and different wavelengths.


title: Creating Quantum Cluster States embedded in ancillary baths

abstract:
  We propose a systematic and explicit method for the inverse engineering of
the dynamics of an open quantum systems with no auxiliary Hamiltonian nor the
prerequisite of adiabatic passage. In particular, we exploit the Lindblad
dissipators in order to create a resource state or subspace of interest in the
presence of decoherence. In a conceptual shift, the Lindblad dissipators,
including multiple interactions that are central to determine the steady state
in the long-time limit for an open quantum system, can be guided to produce a
useful practical resource to achieve an arbitrary target state or subspace.
More importantly, with the help of gate and circuit-based quantum control, we
provide an explicit, programmable, and polynomially efficient control sequence
to create a cluster state or graph state useful for one-way quantum computing.


title: Weber's formula for the bitangents of a smooth plane quartic

abstract:
  In a section of his 1876 treatise Theorie der Abel'schen Functionen vom
Geschlecht 3 Weber proved a formula that expresses the bitangents of a
non-singular plane quartic in terms of Riemann theta constants
(Thetanullwerte). The present note is devoted to a modern presentation of
Weber's formula. In the end a connection with the universal bitangent matrix is
also displayed.


title: PT-symmetric spectral singularity and negative frequency resonance

abstract:
  Vacuum consists of a bath of balanced and symmetric positive and negative
frequency fluctuations. Media in relative motion or accelerated observers can
break this symmetry and preferentially amplify negative frequency modes as in
Quantum Cherenkov radiation and Unruh radiation. Here, we show the existence of
a universal negative frequency-momentum mirror symmetry in the relativistic
Lorentzian transformation for electromagnetic waves. We show the connection of
our discovered symmetry to parity-time (PT) symmetry in moving media and the
resulting spectral singularity in vacuum fluctuation related effects. We prove
that this spectral singularity can occur in the case of two metallic plates in
relative motion interacting through positive and negative frequency plasmonic
fluctuations (negative frequency resonance). Our work paves the way for
understanding the role of PT-symmetric spectral singularities in amplifying
fluctuations and motivates the search for PT-symmetry in novel photonic
systems.


title:
Uncertainty relations: An operational approach to the error-disturbance
  tradeoff

abstract:
  The notions of error and disturbance appearing in quantum uncertainty
relations are often quantified by the discrepancy of a physical quantity from
its ideal value. However, these real and ideal values are not the outcomes of
simultaneous measurements, and comparing the values of unmeasured observables
is not necessarily meaningful according to quantum theory. To overcome these
conceptual difficulties, we take a different approach and define error and
disturbance in an operational manner. In particular, we formulate both in terms
of the probability that one can successfully distinguish the actual measurement
device from the relevant hypothetical ideal by any experimental test
whatsoever. This definition itself does not rely on the formalism of quantum
theory, avoiding many of the conceptual difficulties of usual definitions. We
then derive new Heisenberg-type uncertainty relations for both joint
measurability and the error-disturbance tradeoff for arbitrary observables of
finite-dimensional systems, as well as for the case of position and momentum.
Our relations may be directly applied in information processing settings, for
example to infer that devices which can faithfully transmit information
regarding one observable do not leak any information about conjugate
observables to the environment. We also show that Englert's wave-particle
duality relation [PRL 77, 2154 (1996)] can be viewed as an error-disturbance
uncertainty relation.


title: Viscous Conformal Gauge Theories

abstract:
  We present the conformal behavior of the shear viscosity-to-entropy density
ratio and the fermion-number diffusion coefficient within the perturbative
regime of the conformal window for gauge-fermion theories.


title:
Gravity gradient suppression in spaceborne atomic tests of the
  equivalence principle

abstract:
  The gravity gradient is one of the most serious systematic effects in atomic
tests of the equivalence principle (EP). While differential acceleration
measurements performed with different atomic species under free fall test the
validity of EP, minute displacements between the test masses in a gravity
gradient produces a false EP-violating signal that limits the precision of the
test. We show that gravity inversion and modulation using a gimbal mount can
suppress the systematics due to gravity gradients caused by both moving and
stationary parts of the instrument as well as the environment, strongly
reducing the need to overlap two species.

categories: physics.atom-ph gr-qc physics.space-ph quant-ph


title:
Charge-induced electrochemical actuation of armchair carbon nanotube
  bundles

abstract:
  The effects of charge doping on the structural deformation and on the
electronic structure of armchair single wall carbon nanotube (SWNT) bundles are
investigated through first-principles calculations. In particular, we select a
(6; 6) SWNT as an example and we calculate a mechanical deformation in the SWNT
bundles as a function of gate voltage, which could serve as a basis of the
electromechanical actuators in an artificial muscle. We find that the
magnitudes of the actuation responses such as strain and stress of the (6; 6)
SWNT bundle in the case of hole doping are substantially larger than those of
electron doping. The (6; 6) SWNT bundle also exhibits a low-symmetry and opens
an energy band gap of about 0.41 eV around the charge neutral condition, which
allows a semiconductor-to-metal transition in the electron-doping regime when
the relative shift of the Fermi energy goes up to 0.60 eV, above which the
Young modulus increases.


title: Logic and Topology for Knowledge, Knowability, and Belief

abstract:
  In recent work, Stalnaker proposes a logical framework in which belief is
realized as a weakened form of knowledge. Building on Stalnaker's core
insights, and using frameworks developed in previous work by Bjorndahl and
Baltag et al., we employ topological tools to refine and, we argue, improve on
this analysis. The structure of topological subset spaces allows for a natural
distinction between what is known and (roughly speaking) what is knowable; we
argue that the foundational axioms of Stalnaker's system rely intuitively on
both of these notions. More precisely, we argue that the plausibility of the
principles Stalnaker proposes relating knowledge and belief relies on a subtle
equivocation between an "evidence-in-hand" conception of knowledge and a weaker
"evidence-out-there" notion of what could come to be known. Our analysis leads
to a trimodal logic of knowledge, knowability, and belief interpreted in
topological subset spaces in which belief is definable in terms of knowledge
and knowability. We provide a sound and complete axiomatization for this logic
as well as its uni-modal belief fragment. We then consider weaker logics that
preserve suitable translations of Stalnaker's postulates, yet do not allow for
any reduction of belief. We propose novel topological semantics for these
irreducible notions of belief, generalizing our previous semantics, and provide
sound and complete axiomatizations for the corresponding logics.


title:
Giant Terahertz Pulses Generated by Relativistic Beam in a Dielectric
  Channel

abstract:
  We analyze the electromagnetic field of a short relativistic electron beam
propagating in a round, hollow dielectric channel. We show that if the beam
propagates with an offset relative to the axis of the channel, in a steady
state, its electromagnetic field outside of the channel extends to large radii
and carries an energy that scales as the Lorentz factor $\gamma$ squared (in
contrast to the scaling $\ln\gamma$ without the channel). When this energy is
converted into a terahertz pulse and focused on a target, the electric field in
the focus can greatly exceed typical values of the field that are currently
achieved by sending beams through thin metallic foils.