title:
Measurement of $K^{+}$ production in charged-current $\nu_{\mu}$
  interactions

abstract:
  Production of K^{+} mesons in charged-current \nu_{\mu} interactions on
plastic scintillator (CH) is measured using MINERvA exposed to the low-energy
NuMI beam at Fermilab. Timing information is used to isolate a sample of 885
charged-current events containing a stopping K^{+} which decays at rest. The
differential cross section in K^{+} kinetic energy, d\sigma/dT_{K}, is observed
to be relatively flat between 0 and 500 MeV. Its shape is in good agreement
with the prediction by the \textsc{genie} neutrino event generator when
final-state interactions are included, however the data rate is lower than the
prediction by 15\%.


title: Optimal Monotone Drawings of Trees

abstract:
  A monotone drawing of a graph G is a straight-line drawing of G such that,
for every pair of vertices u,w in G, there exists abpath P_{uw} in G that is
monotone in some direction l_{uw}. (Namely, the order of the orthogonal
projections of the vertices of P_{uw} on l_{uw} is the same as the order they
appear in P_{uw}.)
  The problem of finding monotone drawings for trees has been studied in
several recent papers. The main focus is to reduce the size of the drawing.
Currently, the smallest drawing size is O(n^{1.205}) x O(n^{1.205}). In this
paper, we present an algorithm for constructing monotone drawings of trees on a
grid of size at most 12n x 12n. The smaller drawing size is achieved by a new
simple Path Draw algorithm, and a procedure that carefully assigns primitive
vectors to the paths of the input tree T.
  We also show that there exists a tree T_0 such that any monotone drawing of
T_0 must use a grid of size Omega(n) x Omega(n). So the size of our monotone
drawing of trees is asymptotically optimal.


title:
A new instrument for high statistics measurement of photomultiplier
  characteristics

abstract:
  Since the early days of experimental particle physics photomultipliers (PMTs)
have played an important role in the detector design. Thanks to their
capability of fast photon counting, PMTs are extensively used in the
new-generation of astroparticle physics experiments, such as air, ice and water
Cherenkov detectors. Small size PMTs ($\leq $ 3 inches diameter) show little
sensitivity to the Earth magnetic field, small transit time, stable transit
time spread; the price per photocathode area is less comparing to the one for
the large area PMTs, typically used so far in such applications. Together with
developments and reduced price of multichannel electronics, the use of PMTs of
3-inches or smaller diameter is a promising option even for nowadays large
volume detectors.
  In this paper we report on the design and performance of a new instrument for
mass characterisation of PMTs (from 1 inch to 3 inches size), capable to
calibrate hundreds of PMTs per day and provide measurements of dark counts,
signal amplitude, late-, delayed-, pre- and after-pulses, transit time and
transit time spread.


title:
Tracking three-phase coexistences in binary mixtures of hard plates and
  spheres

abstract:
  The stability of demixing phase transition in binary mixtures of hard plates
(with thickness L and diameter D) and hard spheres (with diameter $\sigma$) is
studied by means of Parsons-Lee theory. The isotropic-isotropic demixing, which
is found in mixtures of large spheres and small plates, is very likely to be
preempted by crystallization. In contrast, the nematic-nematic demixing, which
is obtained in mixtures of large plates and small spheres, can be stabilized at
low diameter ratios ($\sigma$/D) and aspect ratios (L/D). At intermediate
values of $\sigma$/D, where the sizes of the components are similar, neither
the isotropic-isotropic nor the nematic-nematic demixing can be stabilized, but
a very strong fractionation takes place between a plate rich nematic and a
sphere rich isotropic phases. Our results show that the excluded volume
interactions are capable alone to explain the experimental observation of the
nematic-nematic demixing, but they fail for the description of
isotropic-isotropic one (Chen et. al., Soft Matter, 11, 5775 (2015)).


title:
Max-Information, Differential Privacy, and Post-Selection Hypothesis
  Testing

abstract:
  In this paper, we initiate a principled study of how the generalization
properties of approximate differential privacy can be used to perform adaptive
hypothesis testing, while giving statistically valid $p$-value corrections. We
do this by observing that the guarantees of algorithms with bounded approximate
max-information are sufficient to correct the $p$-values of adaptively chosen
hypotheses, and then by proving that algorithms that satisfy
$(\epsilon,\delta)$-differential privacy have bounded approximate max
information when their inputs are drawn from a product distribution. This
substantially extends the known connection between differential privacy and
max-information, which previously was only known to hold for (pure)
$(\epsilon,0)$-differential privacy. It also extends our understanding of
max-information as a partially unifying measure controlling the generalization
properties of adaptive data analyses. We also show a lower bound, proving that
(despite the strong composition properties of max-information), when data is
drawn from a product distribution, $(\epsilon,\delta)$-differentially private
algorithms can come first in a composition with other algorithms satisfying
max-information bounds, but not necessarily second if the composition is
required to itself satisfy a nontrivial max-information bound. This, in
particular, implies that the connection between
$(\epsilon,\delta)$-differential privacy and max-information holds only for
inputs drawn from product distributions, unlike the connection between
$(\epsilon,0)$-differential privacy and max-information.


title: Charged oscillator quantum state generation with Rydberg atoms

abstract:
  We explore the possibility of engineering quantum states of a charged
mechanical oscillator by coupling it to a stream of atoms in superpositions of
high-lying Rydberg states. Our scheme relies on the driving of a two-phonon
resonance within the oscillator by coupling it to an atomic two-photon
transition. This approach effectuates a controllable open system dynamics on
the oscillator that permits the dissipative creation of squeezed and other
non-classical states which are central to applications such as sensing and
metrology or for studies of fundamental questions concerning the boundary
between classical and quantum mechanical descriptions of macroscopic objects.
We show that these features are robust to thermal noise arising from a coupling
of the oscillator with the environment. Finally, we assess the feasibility of
the scheme finding that the required coupling strengths are challenging to
achieve with current state-of-the-art technology.


title: Periodicity of chaotic solutions

abstract:
  The scope of the paper is the analysis of the impact of flow reversal on the
dynamics of cascades of reactors. Periodic and chaotic oscillations occur in
the analyzed system. There is a dependence between the oscillation period of
the state variable of the system without flow reversal and the recurrence
period of windows of chaos in the steady-state diagram of the system with flow
reversal.


title:
Collections of parabolic orbits in homogeneous spaces, homogeneous
  dynamics and hyperkahler geometry

abstract:
  Let $M$ be a hyperk\"ahler manifold with $b_2(M)\geq 5$. We improve our
earlier results on the Morrison-Kawamata cone conjecture by showing that the
Beauville-Bogomolov square of the primitive MBM classes (i.e. the classes whose
orthogonal hyperplanes bound the K\"ahler cone in the positive cone, or, in
other words, the classes of negative extremal rational curves on deformations
of $M$) is bounded in absolute value by a number depending only on the
deformation class of $M$. The proof uses ergodic theory on homogeneous spaces.


title: PT-Symmetric Model of Immune Response

abstract:
  The study of PT-symmetric physical systems began in 1998 as a complex
generalization of conventional quantum mechanics, but beginning in 2007
experiments began to be published in which the predicted PT phase transition
was clearly observed in classical rather than in quantum-mechanical systems.
This paper examines the PT phase transition in mathematical models of
antigen-antibody systems. A surprising conclusion that can be drawn from these
models is that a possible way to treat a serious disease in which the antigen
concentration is growing out of bounds (and the host will die) is to inject a
small dose of a second (different) antigen. In this case there are two possible
favorable outcomes. In the unbroken-PT-symmetric phase the disease becomes
chronic and is no longer lethal while in the appropriate broken-PT-symmetric
phase the concentration of lethal antigen goes to zero and the disease is
completely cured.


title:
Wave-function inspired density functional applied to the H$_2$/H$_2^+$
  challenge

abstract:
  We start from the Bethe-Goldstone equation (BGE) to derive a simple
orbital-dependent correlation functional -- BGE2 -- which terminates the BGE
expansion at the second-order, but retains the self-consistent coupling of
electron-pair orrelations. We demonstrate that BGE2 is size consistent and
one-electron "self-correlation" free. The electron-pair correlation coupling
ensures the correct H$_2$ dissociation limit and gives a finite correlation
energy for any system even if it has a no energy gap. BGE2 provides a good
description of both H$_2$ and H$_2^+$ dissociation, which is regarded as a
great challenge in density functional theory (DFT). We illustrate the behavior
of BGE2 analytically by considering H$_2$ in a minimal basis. Our analysis
shows that BGE2 captures essential features of the adiabatic connection path
that current state-of-the-art DFT approximations do not.


title:
Efficient Algorithms for Large-scale Generalized Eigenvector Computation
  and Canonical Correlation Analysis

abstract:
  This paper considers the problem of canonical-correlation analysis (CCA)
(Hotelling, 1936) and, more broadly, the generalized eigenvector problem for a
pair of symmetric matrices. These are two fundamental problems in data analysis
and scientific computing with numerous applications in machine learning and
statistics (Shi and Malik, 2000; Hardoon et al., 2004; Witten et al., 2009).
  We provide simple iterative algorithms, with improved runtimes, for solving
these problems that are globally linearly convergent with moderate dependencies
on the condition numbers and eigenvalue gaps of the matrices involved.
  We obtain our results by reducing CCA to the top-$k$ generalized eigenvector
problem. We solve this problem through a general framework that simply requires
black box access to an approximate linear system solver. Instantiating this
framework with accelerated gradient descent we obtain a running time of
$O(\frac{z k \sqrt{\kappa}}{\rho} \log(1/\epsilon) \log
\left(k\kappa/\rho\right))$ where $z$ is the total number of nonzero entries,
$\kappa$ is the condition number and $\rho$ is the relative eigenvalue gap of
the appropriate matrices.
  Our algorithm is linear in the input size and the number of components $k$ up
to a $\log(k)$ factor. This is essential for handling large-scale matrices that
appear in practice. To the best of our knowledge this is the first such
algorithm with global linear convergence. We hope that our results prompt
further research and ultimately improve the practical running time for
performing these important data analysis procedures on large data sets.


title:
Quasi-two-dimensional Dirac fermions and quantum magnetoresistance in
  LaAgBi$_2$

abstract:
  We report quasi-two-dimensional Dirac fermions and quantum magnetoresistance
in LaAgBi$_2$. The band structure shows several narrow bands with nearly linear
energy dispersion and Dirac-cone-like points at the Fermi level. The quantum
oscillation experiments revealed one quasi-two-dimensional Fermi pocket and
another complex pocket with small cyclotron resonant mass. The in-plane
transverse magnetoresistance exhibits a crossover at a critical field $B^*$
from semiclassical weak-field $B^2$ dependence to the high-field unsaturated
linear magnetoresistance which is attributed to the quantum limit of the Dirac
fermions. Our results suggest the existence of quasi 2D Dirac fermions in
rare-earth based layered compounds with two-dimensional double-sized Bi square
nets, similar to (Ca,Sr)MnBi$_{2}$, irrespective of magnetic order.


title:
A simple proof of Kotake-Narasimhan theorem in some classes of
  ultradifferentiable functions

abstract:
  We give a simple proof of a general theorem of Kotake-Narasimhan for elliptic
operators in the setting of ultradifferentiable functions in the sense of
Braun, Meise and Taylor. We follow the ideas of Komatsu. Based on an example of
Metivier, we also show that the ellipticity is a necessary condition for the
theorem to be true.


title: Kato's Inequality for Magnetic Relativistic Schr\"odinger Operators

abstract:
  Kato's inequality is shown for the magnetic relativistic Schr\"odinger
operator $H_{A,m}$ defined as the operator theoretical {\it square root} of the
selfadjoint, magnetic nonrelativistic Schr\"odinger operator
$(-i\nabla-A(x))^2+m^2$ with an $L^{2}_{\text{\rm loc}}$ vector potential
$A(x)$.


title: Large-scale imprint of relativistic effects in the cosmic magnification

abstract:
  Apart from the known weak gravitational lensing effect, the cosmic
magnification acquires relativistic corrections owing to Doppler, integrated
Sachs-Wolfe, time-delay and other (local) gravitational potential effects,
respectively. These corrections grow on very large scales and high redshifts z,
which will be the reach of forthcoming surveys. In this work, these
relativistic corrections are investigated in the magnification angular power
spectrum, using both (standard) noninteracting dark energy (DE), and
interacting DE (IDE). It is found that for noninteracting DE, the relativistic
corrections can boost the magnification large-scale power by ~ 40% at z = 3,
and increases at lower z. It is also found that the IDE effect is sensitive to
the relativistic corrections in the magnification power spectrum, particularly
at low z---which will be crucial for constraints on IDE. Moreover, the results
show that if relativistic corrections are not taken into account, this may lead
to an incorrect estimate of the large-scale imprint of IDE in the cosmic
magnification; including the relativistic corrections can enhance the true
potential of the cosmic magnification as a cosmological probe.


title:
Computer-Aided Decision Support for Melanoma Detection Applied on
  Melanocytic and Nonmelanocytic Skin Lesions: A Comparison of Two Systems
  Based on Automatic Analysis of Dermoscopic Images

abstract:
  Commercially available clinical decision support systems (CDSSs) for skin
cancer have been designed for the detection of melanoma only. Correct use of
the systems requires expert knowledge, hampering their utility for nonexperts.
Furthermore, there are no systems to detect other common skin cancer types,
that is, nonmelanoma skin cancer (NMSC). As early diagnosis of skin cancer is
essential, there is a need for a CDSS that is applicable to all types of skin
lesions and is suitable for nonexperts. Nevus Doctor (ND) is a CDSS being
developed by the authors. We here investigate ND's ability to detect both
melanoma and NMSC and the opportunities for improvement. An independent test
set of dermoscopic images of 870 skin lesions, including 44 melanomas and 101
NMSCs, were analysed by ND. Its sensitivity to melanoma and NMSC was compared
to that of Mole Expert (ME), a commercially available CDSS, using the same set
of lesions. ND and ME had similar sensitivity to melanoma. For ND at 95 percent
melanoma sensitivity, the NMSC sensitivity was 100 percent, and the specificity
was 12 percent. The melanomas misclassified by ND at 95 percent sensitivity
were correctly classified by ME, and vice versa. ND is able to detect NMSC
without sacrificing melanoma sensitivity.


title:
Light or heavy supermassive black hole seeds: the role of internal
  rotation in the fate of supermassive stars

abstract:
  Supermassive black holes are a key ingredient of galaxy evolution. However,
their origin is still highly debated. In one of the leading formation
scenarios, a black hole of $\sim100$ M$_{\odot}$ results from the collapse of
the inner core of a supermassive star ($\gtrsim 10^{4-5}$ M$_{\odot}$), created
by the rapid accumulation ($\gtrsim 0.1 $ M$_{\odot}$ yr$^{-1}$) of pristine
gas at the centre of newly formed galaxies at $z\sim 15$. The subsequent
evolution is still speculative: the remaining gas in the supermassive star can
either directly plunge into the nascent black hole, or part of it can form a
central accretion disc, whose luminosity sustains a surrounding, massive, and
nearly hydrostatic envelope (a system called a "quasi-star"). To address this
point, we consider the effect of rotation on a quasi-star, as angular momentum
is inevitably transported towards the galactic nucleus by the accumulating gas.
Using a model for the internal redistribution of angular momentum that
qualitative matches results from simulations of rotating convective stellar
envelopes, we show that quasi-stars with an envelope mass greater than a few
$10^{5}$ M$_{\odot} \times (\rm black~hole~mass/100 M_{\odot})^{0.82}$ have
highly sub-keplerian gas motion in their core, preventing gas circularisation
outside the black hole's horizon. Less massive quasi-stars could form but last
for only $\lesssim 10^4$ years before the accretion luminosity unbinds the
envelope, suppressing the black hole growth. We speculate that this might
eventually lead to a dual black hole seed population: (i) massive ($>10^{4}$
M$_{\odot}$) seeds formed in the most massive ($> 10^{8}$ M$_{\odot}$) and rare
haloes; (ii) lighter ($\sim 10^{2}$ M$_{\odot}$) seeds to be found in less
massive and therefore more common haloes.


title:
Evidence for the alignment of quasar radio polarizations with large
  quasar group axes

abstract:
  Recently, evidence has been presented for the polarization vectors from
quasars to preferentially align with the axes of the large quasar groups (LQG)
to which they belong. This report was based on observations made at optical
wavelengths for two large quasar groups at redshift $\sim 1.3$. The correlation
suggests that the spin axes of quasars preferentially align with their
surrounding large-scale structure that is assumed to be traced by the LQGs.
Here, we consider a large sample of LQGs built from the Sloan Digital Sky
Survey DR7 quasar catalogue in the redshift range $1.0-1.8$. For quasars
embedded in this sample, we collected radio polarization measurements with the
goal to study possible correlations between quasar polarization vectors and the
major axis of their host LQGs. Assuming the radio polarization vector is
perpendicular to the quasar spin axis, we found that the quasar spin axis is
preferentially parallel to the LQG major axis inside LQGs that have at least
$20$ members. This result independently supports the observations at optical
wavelengths. We additionally found that when the richness of an LQG decreases,
the quasar spin axis becomes preferentially perpendicular to the LQG major axis
and that no correlation is detected for quasar groups with fewer than $10$
members.


title: Mono-top Signature from Supersymmetric $t \bar t H$ Channel

abstract:
  We point out that a distinctive mono-top signature is present in Natural SUSY
scenarios when a scalar top-quark and higgsinos are almost mass degenerate.
This signature originates from a supersymmetric counter part of the $t \bar t
H$ process, i.e. $pp \to \tilde t t \tilde h$. Unlike mono-jet signatures
exploiting initial state radiation, this channel can be regarded as a smoking
gun signature of a light stop and higgsinos, allowing a direct probe of the
stop and neutralino sectors. The production rate of this channel largely
depends on the up-type higgsino components in the neutralinos while the stop
sector is sensitive to angular distributions of top-quark's decay products. We
develop an optimal search strategy to capture the supersymmetric $t \bar t H$
process and find that a high luminosity LHC can probe the stop and higgsino
sectors with $m_{\tilde t_1} \lesssim 380$ GeV and $m_{\tilde t_1} - m_{\tilde
\chi_1^0} \lesssim m_W$. Additionally, we propose a kinematic variable with
which one can measure the stop mixing in this channel.


title:
Measurement of the integrated Sachs-Wolfe effect using the AllWISE data
  release

abstract:
  One of the physical features of a dark-energy-dominated universe is the
integrated Sachs-Wolfe (ISW) effect on the cosmic microwave background (CMB)
radiation, which gives us a direct observational window to detect and study
dark energy. The AllWISE data release of the Wide-field Infrared Survey
Explorer (WISE) has a large number of point sources, which span over a wide
redshift range including where the ISW effect is maximized. AllWISE data is
thus very well-suited for the ISW effect studies. In this study, we
cross-correlate AllWISE galaxy and active galactic nucleus (AGN) overdensities
with the Wilkinson Microwave Anisotropy Probe CMB temperature maps to detect
the ISW effect signal. We calibrate the biases for galaxies and AGNs by
cross-correlating the galaxy and AGN overdensities with the Planck lensing
convergence map. We measure the ISW effect signal amplitudes relative to the
$\Lambda$CDM expectation of $A=1$ to be $A=1.18 \pm 0.36$ for galaxies and
$A=0.64 \pm 0.74$ for AGNs . The detection significances for the ISW effect
signal are $3.3\sigma$ and $0.9\sigma$ for galaxies and AGNs respectively
giving a combined significance of $3.4\sigma$. Our result is in agreement with
the $\Lambda$CDM model.


title: Toward a coherent solution of diphoton and flavor anomalies

abstract:
  We propose a coherent explanation for the 750 GeV diphoton anomaly and the
hints of deviations from Lepton Flavor Universality in B decays in terms a new
strongly interacting sector with vectorlike confinement. The diphoton excess
arises from the decay of one of the pseudo-Nambu-Goldstone bosons of the new
sector, while the flavor anomalies are a manifestation of the exchange of the
corresponding vector resonances (with masses in the 1.5-2.5 TeV range). We
provide explicit examples (with detailed particle content and group structure)
of the new sector, discussing both the low-energy flavor-physics phenomenology
and the signatures at high $p_T$. We show that specific models can provide an
excellent fit to all available data. A key feature of all realizations is a
sizable broad excess in the tails of $\tau^+ \tau^-$ invariant mass
distribution in $p p \to \tau^+ \tau^-$, that should be accessible at the LHC
in the near future.


title: A Survey for H-alpha Emission from Late L dwarfs and T dwarfs

abstract:
  Recently, studies of brown dwarfs have demonstrated that they possess strong
magnetic fields and have the potential to produce radio and optical auroral
emissions powered by magnetospheric currents. This emission provides the only
window on magnetic fields in the coolest brown dwarfs and identifying
additional benchmark objects is key to constraining dynamo theory in this
regime. To this end, we conducted a new red optical (6300 - 9700 Angstrom)
survey with the Keck telescopes looking for H-alpha emission from a sample of
late L dwarfs and T dwarfs. Our survey gathered optical spectra for 29 targets,
18 of which did not have previous optical spectra in the literature, greatly
expanding the number of moderate resolution (R~2000) spectra available at these
spectral types. Combining our sample with previous surveys, we confirm an
H-alpha detection rate of 9.2 (+3.5/-2.1) % for L and T dwarfs in the optical
spectral range of L4 - T8. This detection rate is consistent with the recently
measured detection rate for auroral radio emission from Kao et al. (2016),
suggesting that geometrical selection effects due to the beaming of the radio
emission are small or absent. We also provide the first detection of H-alpha
emission from 2MASS 0036+1821, previously notable as the only electron
cyclotron maser radio source without a confirmed detection of H-alpha emission.
Finally, we also establish optical standards for spectral types T3 and T4,
filling in the previous gap between T2 and T5.


title:
MN48: a new Galactic bona fide luminous blue variable revealed by
  Spitzer and SALT

abstract:
  In this paper, we report the results of spectroscopic and photometric
observations of the candidate evolved massive star MN48 disclosed via detection
of a mid-infrared circular shell around it with the Spitzer Space Telescope.
Follow-up optical spectroscopy of MN48 with the Southern African Large
Telescope (SALT) carried out in 2011--2015 revealed significant changes in the
spectrum of this star, which are typical of luminous blue variables (LBVs). The
LBV status of MN48 was further supported by photometric monitoring which shows
that in 2009--2011 this star has brightened by approx 0.9 and 1 mag in the V
and I_c bands, respectively, then faded by approx 1.1 and 1.6 mag during the
next four years, and apparently started to brighten again recently. The
detected changes in the spectrum and brightness of MN48 make this star the 18th
known Galactic bona fide LBV and increase the percentage of LBVs associated
with circumstellar nebulae to more than 70 per cent. We discuss the possible
birth place of MN48 and suggest that this star might have been ejected either
from a putative star cluster embedded in the HII region IRAS 16455-4531 or the
young massive star cluster Westerlund 1.


title: Do open star clusters evolve toward energy equipartition?

abstract:
  We investigate whether open clusters (OCs) tend to energy equipartition, by
means of direct N-body simulations with a broken power-law mass function. We
find that the simulated OCs become strongly mass segregated, but the local
velocity dispersion does not depend on the stellar mass for most of the mass
range: the curve of the velocity dispersion as a function of mass is nearly
flat even after several half-mass relaxation times, regardless of the adopted
stellar evolution recipes and Galactic tidal field model. This result holds
both if we start from virialized King models and if we use clumpy sub-virial
initial conditions. The velocity dispersion of the most massive stars and
stellar remnants tends to be higher than the velocity dispersion of the lighter
stars. This trend is particularly evident in simulations without stellar
evolution. We interpret this result as a consequence of the strong mass
segregation, which leads to Spitzer's instability. Stellar winds delay the
onset of the instability. Our simulations strongly support the result that OCs
do not attain equipartition, for a wide range of initial conditions.


title: The Gravity Dual of Boundary Causality

abstract:
  In gauge/gravity duality, points which are not causally related on the
boundary cannot be causally related through the bulk; this is the statement of
boundary causality. By the Gao-Wald theorem, the averaged null energy condition
in the bulk is sufficient to ensure this property. Here we proceed in the
converse direction: we derive a necessary as well as sufficient condition for
the preservation of boundary causality under perturbative (quantum or stringy)
corrections to the bulk. The condition that we find is a (background-dependent)
constraint on the amount by which light cones can "open" over all null bulk
geodesics. We show that this constraint is weaker than the averaged null energy
condition.


title: The Kinematics of CIV in Star-Forming Galaxies at z~1.2

abstract:
  We present the first statistical sample of rest-frame far-UV spectra of
star-forming galaxies at z~1. These spectra are unique in that they cover the
high-ionization CIV{\lambda}{\lambda}1548, 1550 doublet. We also detect
low-ionization features such as SiII{\lambda}1527, FeII{\lambda}1608,
AlII{\lambda}1670, NiII{\lambda}{\lambda}1741, 1751 and SiII{\lambda}1808, and
intermediate-ionization features from AlIII{\lambda}{\lambda}1854, 1862.
Comparing the properties of absorption lines of lower- and higher- ionization
states provides a window into the multi-phase nature of circumgalactic gas. Our
sample is drawn from the DEEP2 survey and spans the redshift range 1.01 < z <
1.35 (<z> = 1.25). By isolating the interstellar CIV absorption from the
stellar P-Cygni wind profile we find that 69% of the CIV profiles are
blueshifted with respect to the systemic velocity. Furthermore, CIV shows a
small but significant blueshift relative to FeII (offset of the best-fit linear
regression -76 $\pm$ 26 km/s). At the same time, the CIV blueshift is on
average comparable to that of MgII{\lambda}{\lambda}2796, 2803. At this point,
in explaining the larger blueshift of CIV absorption at the ~ 3-sigma level, we
cannot distinguish between the faster motion of highly-ionized gas relative to
gas traced by FeII, and filling in on the red side from resonant CIV emission.
We investigate how far-UV interstellar absorption kinematics correlate with
other galaxy properties using stacked spectra. These stacking results show a
direct link between CIV absorption and the current SFR, though we only observe
small velocity differences among different ionization states tracing the
outflowing ISM.


title:
Gamma-ray bursts from massive Population III stars: clues from the radio
  band

abstract:
  Current models suggest gamma-ray bursts could be used as a way of probing
Population III stars - the first stars in the early Universe. In this paper we
use numerical simulations to demonstrate that late time radio observations of
gamma-ray burst afterglows could provide a means of identifying bursts that
originate from Population III stars, if these were highly massive,
independently from their redshift. We then present the results from a pilot
study using the Australia Telescope Compact Array at 17 GHz, designed to test
the hypothesis that there may be Population III gamma-ray bursts amongst the
current sample of known events. We observed three candidates plus a control
gamma-ray burst, and make no detections with upper limits of 20-40 uJy at
500-1300 days post explosion.


title:
Tunable Weyl fermions and Fermi arcs in magnetized topological
  crystalline insulators

abstract:
  Based on $k\cdot p$ analysis and realistic tight-binding calculations, we
find that time-reversal-breaking Weyl semimetals can be realized in
magnetically-doped (Mn, Eu, Cr etc.) Sn$_{1-x}$Pb$_x$(Te,Se) class of
topological crystalline insulators. All the Weyl points are well separated in
momentum space and possess nearly the same energy due to high crystalline
symmetry. Moreover, both the Weyl points and Fermi arcs are highly tunable by
varying Pb/Sn composition, pressure, magnetization, temperature, surface
potential etc., opening up the possibility of manipulating Weyl points and
rewiring the Fermi arcs.


title:
Bulk spectroscopic measurement of the topological charge of Weyl nodes
  with resonant x-rays

abstract:
  We formulate a bulk spectroscopic method for direct measurement of the
topological invariant of nondegenerate band crossings in Weyl semimetals. We
demonstrate how polarization-resolved resonant x-ray scattering captures the
winding of the Berry flux around Weyl nodes. The spectra obtained by the
proposed strategy feature an integer number of zero-crossings that is directly
related to the topological charge of the measured nodes. We benchmark the
proposed protocol on TaAs, using realistic low-energy models derived from
density-functional theory to accurately represent the states close to the Fermi
level, including sizable deviations from the idealized linear dispersion. We
conclude that the proposed measurement, which is within the reach of current
experimental setups, yields direct signatures of nontrivial band topology in
spectroscopy of three-dimensional bulk matter.


title:
Magneto-transport measurements on
  Nd$_{1.83}$Ce$_{0.17}$CuO$_{4\pm\delta}$ thin films

abstract:
  Nd$_{2-x}$Ce$_x$CuO$_{4\pm\delta}$ (NCCO) epitaxial thin films have been
deposited on (100) SrTiO$_3$ substrates by DC sputtering technique in different
atmosphere. The as-grown samples show different dependence of the in-plane
resistivity at low temperature, when they are grown in pure argon atmosphere or
in oxygen. Moreover, an unusual behaviour is also found when transport takes
place in the presence of an external magnetic field. It is commonly accepted
that the higher anisotropic properties of NCCO crystalline cell with respect to
the hole doped YBCO and LSCO and the electric conduction mainly confined in the
CuO$_2$ plane, strongly support the two-dimensional (2D) character of the
current transport in this system. Results on the temperature dependence of the
resistance, as well as on the magnetoresistance and the Hall coefficient,
obtained on epitaxial NCCO thin films in the over-doped region ($x\ge0.15$) of
the phase diagram are presented and discussed.


title: Scalar Chiral Spin-1/2 Order on Kagome Lattices in Nd3Sb3Mg2O14

abstract:
  We introduce $\mathrm{Nd_{3}Sb_{3}Mg_{2}O_{14}}$ with ideal kagome lattices
of neodymium ions in ABC stacking. Thermodynamic measurements show a
Curie-Weiss temperature of $\Theta_{CW}=-0.12~$K, a Nd$^{3+}$ spin-1/2 Kramers
doublet ground state, and a second order phase transition at $T_N=0.56(2)~$K.
Neutron scattering reveals non-coplanar scalar chiral ${\bf k} =0$ magnetic
order with a correlation length exceeding 400 \AA = 55 $a$ and an ordered
moment of $1.79(5)~\mu_B$. This order includes a canted ferromagnetic component
perpendicular to the kagome planes favored by Dzyaloshinskii-Moriya
interactions.


title: Free coherent spinons in quantum square ice

abstract:
  We investigate the quantum dynamics of monopole-like excitations in quantum
square ice, as captured by the strongly anisotropic spin-1/2 XXZ model on the
checkerboard lattice. We obtain exact results for excitation dynamics in both
analytically solvable effective models and a fully interacting model of quantum
square ice on finite clusters. We find that the dispersive lower bound of the
dynamic response of freely propagating spinons is recovered in the dynamic
structure factor of the interacting system, yielding a marked fingerprint of
coherent spinon dispersion. Our results provide unbiased evidence for the
formation of coherent quasiparticles propagating freely in the correlated
"vacuum" of quantum square ice.


title: Topological Insulators from Group Cohomology

abstract:
  We classify insulators by generalized symmetries that combine space-time
transformations with quasimomentum translations. Our group-cohomological
classification generalizes the nonsymmorphic space groups, which extend point
groups by real-space translations, i.e., nonsymmorphic symmetries unavoidably
translate the spatial origin by a fraction of the lattice period. Here, we
further extend nonsymmorphic groups by reciprocal translations, thus placing
real and quasimomentum space on equal footing. We propose that group cohomology
provides a symmetry-based classification of quasimomentum manifolds, which in
turn determines the band topology. In this sense, cohomology underlies band
topology. Our claim is exemplified by the first theory of
time-reversal-invariant insulators with nonsymmorphic spatial symmetries. These
insulators may be described as 'piecewise topological', in the sense that
subtopologies describe the different high-symmetry submanifolds of the
Brillouin zone, and the various subtopologies must be pieced together to form a
globally consistent topology. The subtopologies that we discovered include: a
glide-symmetric analog of the quantum spin Hall effect, an hourglass-flow
topology (exemplified by our recently-proposed KHgSb material class), and
quantized non-Abelian polarizations. Our cohomological classification results
in an atypical bulk-boundary correspondence for our topological insulators.


title:
ALMA 0.1-0.2 arcsec resolution imaging of the NGC 1068 nucleus - compact
  dense molecular gas emission at the putative AGN location

abstract:
  We present the results of our ALMA Cycle 2 high angular resolution (0.1-0.2
arcsec) observations of the nuclear region of the nearby well-studied type-2
active galactic nucleus (AGN), NGC 1068, at HCN J=3-2 and HCO+ J=3-2 emission
lines. For the first time, due to a higher angular resolution than previous
studies, we clearly detected dense molecular gas emission at the putative AGN
location, identified as a ~1.1 mm (~266 GHz) continuum emission peak, by
separating this emission from brighter emission located at 0.5-2.0 arcsec on
the eastern and western sides of the AGN. The estimated intrinsic molecular
emission size and dense molecular mass, which are thought to be associated with
the putative dusty molecular torus around an AGN, were ~10 pc and ~several x
10^5 Msun, respectively. HCN-to-HCO+ J=3-2 flux ratios substantially higher
than unity were found throughout the nuclear region of NGC 1068. The continuum
emission displayed an elongated morphology along the direction of the radio jet
located at the northern side of the AGN, as well as a weak spatially resolved
component at ~2.0 arcsec on the southwestern side of the AGN. The latter
component most likely originated from star formation, with the estimated
luminosity more than one order of magnitude lower than the luminosity of the
central AGN. No vibrationally excited (v2=1f) J=3-2 emission lines were
detected for HCN and HCO+ across the field of view.


title: Chromatic classical symmetric functions

abstract:
  In this note we classify when a skew Schur function is a positive linear
combination of power sum symmetric functions. We then use this to determine
precisely when any scalar multiple of a skew Schur function is the chromatic
symmetric function of some graph. From here we are able to prove that of the
classical bases for symmetric functions only certain scalar multiples of the
elementary symmetric functions can be realised as the chromatic symmetric
function of some graph, namely a particular union of complete graphs.


title: Sound waves and resonances in electron-hole plasma

abstract:
  Inspired by the recent experimental signatures of relativistic hydrodynamics
in graphene, we investigate theoretically the behavior of hydrodynamic sound
modes in such quasi-relativistic fluids near charge neutrality, within linear
response. Locally driving an electron fluid at a resonant frequency to such a
sound mode can lead to large increases in the electrical response at the edges
of the sample, a signature which cannot be explained using diffusive models of
transport. We discuss the robustness of this signal to various effects,
including electron-acoustic phonon coupling, disorder, and long-range Coulomb
interactions. These long range interactions convert the sound mode into a
collective plasmonic mode at low frequencies unless the fluid is charge
neutral. At the smallest frequencies, the response in a disordered fluid is
quantitatively what is predicted by a "momentum relaxation time" approximation.
However, this approximation fails at higher frequencies (which can be
parametrically small), where the classical localization of sound waves cannot
be neglected. Experimental observation of such resonances is a clear signature
of relativistic hydrodynamics, and provides an upper bound on the viscosity of
the electron-hole plasma.


title: Janus Points and Arrows of Time

abstract:
  We clarify and strengthen our demonstration that arrows of time necessarily
arise in unconfined systems. Contrary to a recent claim, this does not require
an improbable selection principle.


title:
RESOLVE and ECO: The Halo Mass-Dependent Shape of Galaxy Stellar and
  Baryonic Mass Functions

abstract:
  In this work, we present galaxy stellar and baryonic (stars plus cold gas)
mass functions (SMF and BMF) and their halo mass dependence for two
volume-limited data sets. The first, RESOLVE-B, coincides with the Stripe 82
footprint and is extremely complete down to baryonic mass Mbary ~ 10^9.1 Msun,
probing the gas-rich dwarf regime below Mbary ~ 10^10 Msun. The second, ECO,
covers a ~40 times larger volume (containing RESOLVE-A) and is complete to
Mbary ~ 10^9.4 Msun. To construct the SMF and BMF we implement a new "cross-bin
sampling" technique with Monte Carlo sampling from the full likelihood
distributions of stellar or baryonic mass. Our SMFs exhibit the "plateau"
feature starting below Mstar ~ 10^10 Msun that has been described in prior
work. However, the BMF fills in this feature and rises as a straight power law
below ~10^10 Msun, as gas-dominated galaxies become the majority of the
population. Nonetheless, the low-mass slope of the BMF is not as steep as that
of the theoretical dark matter halo MF. Moreover, we assign group halo masses
by abundance matching, finding that the SMF and BMF separated into four
physically motivated halo mass regimes reveal complex structure underlying the
simple shape of the overall MFs. In particular, the satellite MFs are depressed
below the central galaxy MF "humps" in groups with mass <10^13.5 Msun yet rise
steeply in clusters. Our results suggest that satellite destruction and/or
stripping are active from the point of nascent group formation. We show that
the key role of groups in shaping MFs enables reconstruction of a given
survey's SMF or BMF based on its group halo mass distribution.


title: Black Hole Mergers and the QCD Axion at Advanced LIGO

abstract:
  In the next few years Advanced LIGO (aLIGO) may see gravitational waves (GWs)
from thousands of black hole (BH) mergers. This marks the beginning of a new
precision tool for physics. Here we show how to search for new physics beyond
the standard model using this tool, in particular the QCD axion in the mass
range ma ~ 10^-14 to 10^-10 eV. Axions (or any bosons) in this mass range cause
rapidly rotating BHs to shed their spin into a large cloud of axions in atomic
Bohr orbits around the BH, through the effect of superradiance (SR). This
results in a gap in the mass vs. spin distribution of BHs when the BH size is
comparable to the axion's Compton wavelength. By measuring the spin and mass of
the merging objects observed at LIGO, we could verify the presence and shape of
the gap in the BH distribution produced by the axion.
  The axion cloud can also be discovered through the GWs it radiates via axion
annihilations or level transitions. A blind monochromatic GW search may reveal
up to 10^5 BHs radiating through axion annihilations, at distinct frequencies
within ~3% of $2 ma. Axion transitions probe heavier axions and may be
observable in future GW observatories. The merger events are perfect candidates
for a targeted GW search. If the final BH has high spin, a SR cloud may grow
and emit monochromatic GWs from axion annihilations. We may observe the SR
evolution in real time.


title: Are Local Causal Models of Quantum Theory Feasible at All?

abstract:
  This article presents an analysis of the extent to which local causal models
or local realistic models of quantum theory (QT), including quantum field
theory (QFT), are theoretically possible and practically feasible in light of
the present state of these theories. Quantum physicists consider Bells famous
inequality and its violation in experiments to be a strong indication that
local realistic or local causal models of QT are not possible and that quantum
theory as a whole is therefore not a local realistic or local causal theory.
Based on a proposed definition of a "formal causal model" for a theory of
physics (such as QT), this paper investigates the possibility of having a local
causal model for QT. Areas of QT are identified in which the construction of a
causal model is impeded because of deficiencies in the state of the respective
theory. It is shown that the removal of the deficiencies can be achieved by the
provision of a causal model. Whereas the construction of a causal model of QT,
including QFT, appears to be feasible after the removal of certain
deficiencies, the construction of a local (causal) model does not appear to be
possible. As a consequence of the conclusion that local (causal) models of
QT/QFT are not possible, if a strong interpretation of locality is assumed, a
locality model is proposed in which the non-localities are confined to "quantum
objects".


title: Optimal kernel estimates for a Schr\"odinger type operator

abstract:
  In the paper the principal result obtained is the estimate for the heat
kernel associated to the Schr\"odinger type operator
$(1+|x|^\alpha)\Delta-|x|^\beta$ \[ k(t,x,y)\leq Ct^{-\frac{\theta}{2}}\frac
{\varphi(x)\varphi(y)}{1+|x|^\alpha}, \] where
$\varphi=(1+|x|^\alpha)^{\frac{2-\theta}{4}+\frac{1}{\alpha}\frac{\theta-N}{2}}$,
$\theta\geq N$ and $0<t<1$, provided that $N>2$, $\alpha> 2$ and
$\beta>\alpha-2$. This estimate improves a similar estimate in \cite
{can-rhan-tac2} with respect to the dependence on spatial component.


title:
Comparison of VLT/X-shooter OH and O2 rotational temperatures with
  consideration of TIMED/SABER emission and temperature profiles

abstract:
  Rotational temperatures Trot derived from lines of the same OH band are an
important method to study the mesopause region near 87 km. To measure realistic
temperatures, the rotational level populations have to be in local
thermodynamic equilibrium (LTE). However, this might not be fulfilled,
especially at high emission altitudes. In order to quantify possible non-LTE
contributions to the OH Trot as a function of the upper vibrational level v',
we studied a sample of 343 echelle spectra taken with the X-shooter
spectrograph at the Very Large Telescope at Cerro Paranal in Chile. These data
allowed us to analyse 25 OH bands in each spectrum. Moreover, we could measure
lines of O2b(0-1), which peaks at 94 to 95 km, and O2a(0-0) with an emission
peak at about 90 km. Since the radiative lifetimes are relatively long, the
derived O2 Trot are not significantly affected by non-LTE contributions. For a
comparison with OH, the differences in the emission profiles were corrected by
using OH emission, O2a(0-0) emission, and CO2-based temperature profile data
from the multi-channel radiometer SABER on the TIMED satellite. For a reference
profile at 90 km, we found a good agreement of the O2 with the SABER-related
temperatures, whereas the OH temperatures, especially for the high and even v',
showed significant excesses with a maximum of more than 10 K for v' = 8. We
could also find a nocturnal trend towards higher non-LTE effects, particularly
for high v'.


title: A traditional tree-style tableau for LTL

abstract:
  Propositional linear time temporal logic (LTL) is the standard temporal logic
for computing applications and many reasoning techniques and tools have been
developed for it. Tableaux for deciding satisfiability have existed since the
1980s. However, the tableaux for this logic do not look like traditional
tree-shaped tableau systems and their processing is often quite complicated. We
present a new simple traditional-style tree-shaped tableau for LTL and prove
that it is sound and complete. As well as being simple to understand, to
introduce to students and to use manually, it also seems simple to implement
and promises to be competitive in its automation. It is particularly suitable
for parallel implementations.


title: Normal forms for non-uniform contractions

abstract:
  Let $f$ be a measure-preserving transformation of a Lebesgue space $(X,\mu)$
and let $\f$ be its extension to a bundle $\E = X \times\Rm$ by smooth fiber
maps $\f_x : \E_x \to \E_{fx}$ so that the derivative of $\f$ at the zero
section has negative Lyapunov exponents. We construct a measurable system of
smooth coordinate changes $\h_x$ on $\E_x$ for $\mu$-a.e. $x$ so that the maps
$\p_x =\h_{fx} \circ \f_x \circ \h_x ^{-1}$ are sub-resonance polynomials in a
finite dimensional Lie group. Our construction shows that such $\h_x$ and
$\p_x$ are unique up to a sub-resonance polynomial. As a consequence, we obtain
the centralizer theorem that the coordinate change $\h$ also conjugates any
commuting extension to a polynomial extension of the same type. We apply our
results to a measure-preserving diffeomorphism $f$ with a non-uniformly
contracting invariant foliation $W$. We construct a measurable system of smooth
coordinate changes $\h_x: W_x \to T_xW$ such that the maps $\h_{fx} \circ f
\circ \h_x ^{-1}$ are polynomials of sub-resonance type. Moreover, we show that
for almost every leaf the coordinate changes exist at each point on the leaf
and give a coherent atlas with transition maps in a finite dimensional Lie
group.


title: The symmetric orbifold of N=2 minimal models

abstract:
  The large level limit of the N=2 minimal models that appear in the duality
with the N=2 supersymmetric higher spin theory on AdS_3 is shown to be a
natural subsector of a certain symmetric orbifold theory. We study the relevant
decompositions in both the untwisted and the twisted sector, and analyse the
structure of the higher spin representations in the twisted sector in some
detail. These results should help to identify the string background of which
the higher spin theory is expected to describe the leading Regge trajectory in
the tensionless limit.


title: Scarcity of cycles for rational functions over a number field

abstract:
  We provide an explicit bound on the number of periodic points of a rational
function defined over a number field, where the bound depends only on the
number of primes of bad reduction and the degree of the function, and is linear
in the degree. More generally, we show that there exists an explicit uniform
bound on the number of periodic points for any rational function in a given
finitely generated semigroup (under composition) of rational functions of
degree at least 2. We show that under stronger assumptions the dependence on
the degree of the map in the bounds can be removed.


title:
Realization of Power-Law Inflation & Variants via Variation of the
  Strong Coupling Constant

abstract:
  We present a model of power law inflation generated by variation of the
strong coupling constant. We then extend the model to two varying coupling
constants which leads to a potential consisting of a linear combination of
exponential terms. Some variants of the latter may be self-consistent and can
accommodate the experimental data of the Planck 2015 and other recent
experiments.


title:
Globules and Pillars in Cygnus X I. Herschel Far-infrared imaging of the
  Cyg OB2 environment

abstract:
  The radiative feedback of massive stars on molecular clouds creates pillars,
globules and other features at the interface between the HII region and
molecular cloud. We present here Herschel observations between 70 and 500
micron of the immediate environment of the Cygnus OB2 association, performed
within the HOBYS program. All structures were detected based on their
appearance at 70 micron, and have been classified as pillars, globules,
evaporating gasous globules (EGGs), proplyd-like objects, and condensations.
From the 70 and 160 micron flux maps, we derive the local FUV field on the PDR
surfaces. In parallel, we use a census of the O-stars to estimate the overall
FUV-field, that is 10^3-10^4 G_0 close to the central OB cluster (within 10 pc)
and decreases down to a few tens G_0, in a distance of 50 pc. From a SED fit to
the four longest Herschel wavelengths, we determine column density and
temperature maps and derive masses, volume densities and surface densities for
these structures. We find that the morphological classification corresponds to
distinct physical properties. Pillars and globules have the longest estimated
photoevaporation lifetimes, a few 10^6 yr, while all other features should
survive less than that. These lifetimes are consistent with that found in
simulations of turbulent, UV-illuminated clouds. We propose a tentative
evolutionary scheme in which pillars can evolve into globules, which in turn
then evolve into EGGs, condensations and proplyd-like objects.


title: Visual Storytelling

abstract:
  We introduce the first dataset for sequential vision-to-language, and explore
how this data may be used for the task of visual storytelling. The first
release of this dataset, SIND v.1, includes 81,743 unique photos in 20,211
sequences, aligned to both descriptive (caption) and story language. We
establish several strong baselines for the storytelling task, and motivate an
automatic metric to benchmark progress. Modelling concrete description as well
as figurative and social language, as provided in this dataset and the
storytelling task, has the potential to move artificial intelligence from basic
understandings of typical visual scenes towards more and more human-like
understanding of grounded event structure and subjective expression.


title: Effects of Beam Size and Pulse Duration on the Laser Drilling Process

abstract:
  A two-dimensional axisymmetric transient laser drilling model is used to
analyze the effects of laser beam diameter and laser pulse duration on the
laser drilling process. The model includes conduction and convection heat
transfer, melting, solidification and vaporization, as well as material removal
resulting from the vaporization and melt ejection. The validated model is
applied to study the effects of laser beam size and pulse duration on the
geometry of the drilled hole. It is found that the ablation effect decrease
with the increasing beam diameter due to the effect of increased vaporization
rate, and deeper hole is observed for the larger pulse width due to the higher
thermal ablation efficiency.


title:
Stability of exact solutions of the nonlinear Schroedinger equation in
  an external potential having supersymmetry and parity-time symmetry

abstract:
  We discuss the stability properties of the solutions of the general nonlinear
Schroedinger equation (NLSE) in 1+1 dimensions in an external potential
derivable from a parity-time (PT) symmetric superpotential $W(x)$ that we
considered earlier [Kevrekedis et al Phys. Rev. E 92, 042901 (2015)]. In
particular we consider the nonlinear partial differential equation $\{ i
\partial_t + \partial_x^2 - V^{-}(x) +| \psi(x,t) |^{2\kappa} \} \, \psi(x,t) =
0$, for arbitrary nonlinearity parameter $\kappa$. We study the bound state
solutions when $V^{-}(x) = (1/4- b^2)$ sech$^2(x)$, which can be derived from
two different superpotentials $W(x)$, one of which is complex and $PT$
symmetric. Using Derrick's theorem, as well as a time dependent variational
approximation, we derive exact analytic results for the domain of stability of
the trapped solution as a function of the depth $b^2$ of the external
potential. We compare the regime of stability found from these analytic
approaches with a numerical linear stability analysis using a variant of the
Vakhitov-Kolokolov (V-K) stability criterion. The numerical results of applying
the V-K condition give the same answer for the domain of stability as the
analytic result obtained from applying Derrick's theorem. Our main result is
that for $\kappa>2$ a new regime of stability for the exact solutions appears
as long as $b > b_{crit}$, where $b_{crit}$ is a function of the nonlinearity
parameter $\kappa$. In the absence of the potential the related solitary wave
solutions of the NLSE are unstable for $\kappa>2$.


title:
A Force-Level Theory of the Rheology of Entangled Rod and Chain Polymer
  Liquids. I. Tube Deformation, Microscopic Yielding and the Nonlinear Elastic
  Limit

abstract:
  We employ a first principles, force-level approach to self-consistently
construct the anharmonic tube confinement field for entangled fluids of rigid
needles and for primitive-path (PP) level chains in two limiting situations
where chain stretching is assumed to either completely relax or remain
unrelaxed. The influence of shear and extensional deformation and polymer
orientation is determined in a nonlinear elastic limit where dissipative
relaxation processes are intentionally neglected. For needles and PP-level
chains, a Gaussian analysis of transverse polymer dynamical fluctuations
predicts that deformation-induced orientation leads to tube dilation. In
contrast, for deformed polymers in which chain stretch does not relax we find
tube compression. For all three systems, a finite maximum transverse
entanglement force localizing the polymers in effective tubes is predicted. The
conditions when this entanglement force can be overcome (a force imbalance) by
an externally applied force associated with macroscopic deformation can be
crisply defined in the nonlinear elastic limit, and the possibility of a
"microscopic absolute yielding" event destroying the tube confinement can be
analyzed. For needles and contour-relaxed PP chains, this force imbalance is
found to occur at a stress of order the equilibrium shear modulus and thus a
strain of order unity, corresponding to a mechanically fragile entanglement
tube field. However, for unrelaxed stretched chains, tube compression
stabilizes transverse polymer confinement, and there appears to be no force
imbalance. These results collectively suggest that the crossover from elastic
to irreversible viscous response requires chain retraction to initiate
disentanglement. We qualitatively discuss comparisons with existing
phenomenological models for nonlinear startup shear, step strain, and creep
rheology experiments.


title:
A Force-Level Theory of the Rheology of Entangled Rod and Chain Polymer
  Liquids. II. Perturbed Reptation, Stress Overshoot, Emergent Convective
  Constraint Release and Steady State Flow

abstract:
  We numerically and analytically analyze the startup continuous shear rheology
of heavily entangled rigid rod polymer fluids based on our self-consistent,
force-level theory of anharmonic tube confinement. The approach is simplified
by neglecting stress-assisted transverse barrier hopping, and irreversible
relaxation proceeds solely via deformation-perturbed reptation. This process is
self-consistently coupled to tube dilation and macroscopic rheological
response. We predict that with increasing strain the tube strongly dilates,
entanglements are lost, and reptation speeds up. As a consequence, a stress
overshoot emerges not due to affine over-orientation, but rather to strong
weakening of the entanglement network. Just beyond the stress overshoot the
longest relaxation time is predicted to scale as the inverse shear rate,
corresponding to the emergence of a generic form of convective constraint
release (CCR). Its origin is a stress-induced local force that
self-consistently couples the mesoscopic tube-scale physics with macroscopic
mechanical response. Tube weakening at the overshoot occurs via the same
qualitative mechanism that leads to microscopic absolute yielding in the
nonlinear elastic scenario analyzed in the preceding paper. The stress
overshoot and emergent CCR thus correspond to an elastic-viscous crossover due
to deformation-induced disentanglement, which at long times and high shear
rates results in a quantitatively sensible flow stress plateau and shear
thinning behavior. We suggest that the predicted behavior for needles is
relevant to flexible chain melts at low Rouse Weissenberg numbers if contour
length equilibration is fast. Quantitative predictions for tube dilation in the
steady state flow of chains melts are favorably compared to a recent
simulation.


title: Relating metric and covariant perturbation theories in $f(R)$ gravity

abstract:
  Modified theories of gravity have been invoked recently as an alternative to
dark energy, in an attempt to explain the apparent accelerated expansion of the
universe at the present time. In order to describe inhomogeneities in
cosmological models, cosmological perturbation theory is used, of which two
formalisms exist: the metric approach and the covariant approach. In this paper
I present the relationship between the metric and covariant approaches for
modeling $f(R)$ theories of gravity. This provides a useful resource that
researchers primarily working with one formalism can use to compare or
translate their results to the other formalism.


title:
Classical field theories from Hamiltonian constraint: Symmetries and
  conservation laws

abstract:
  We discuss the relation between symmetries and conservation laws in the realm
of classical field theories based on the Hamiltonian constraint. In this
approach, spacetime positions and field values are treated on equal footing,
and a generalized multivector-valued momentum is introduced. We derive a
field-theoretic Hamiltonian version of the Noether theorem, and identify
generalized Noether currents with the momentum contracted with
symmetry-generating vector fields. Their relation to the traditional vectorial
Noether currents is then established. Throughout, we employ the mathematical
language of geometric algebra and calculus.


title:
The Ionization Structure of Sharpless 2-264: Multiwavelength
  Observations of the {\lambda} Ori H II Region

abstract:
  We present velocity-resolved maps taken with the Wisconsin H-Alpha Mapper
(WHAM) in H{\alpha}, [S II] {\lambda}6716, and [N II] {\lambda}6583 around the
well-known O8 III star {\lambda} Ori A (HD 36861) (l = 185{\deg} to 205{\deg},
b = -24{\deg} to -1{\deg}). The integrated intensity (v(LSR) = -80 to +80
km/s), I(H{\alpha}), within WHAM's one-degree beams varies from ~ 190 R near
the center to ~ 10 R on the periphery of the nebula where it becomes comparable
to foreground and/or background emission in this complex region. Intensity
ratios for [N II]/H{\alpha} and [S II]/H{\alpha} average 0.28 and 0.35,
respectively. In both ratios, higher values are found preferentially at larger
radii from {\lambda} Ori, although the behavior of [N II]/H{\alpha} is
complicated near the edges of the nebula. The [S II]/[N II] intensity ratio
ranges from ~ 0.5 to ~ 1.0, with the value increasing toward larger radii (and
lower H{\alpha} intensities). Variations of [S II]/H{\alpha}, [N II]/H{\alpha},
and [S II]/[N II] line ratios in this diffuse region show some similar trends
to those seen in the warm ionized medium (WIM) but with generally lower
metal-line ratios. As with the WIM, the trends are driven by changes in the
underlying physical parameters, most notably the ionization states and gas
temperature. We use these extremely high signal-to-noise observations to
construct a map of temperature and non-thermal velocity throughout the nebula.
Using the line widths of H{\alpha} and [S II], we separate thermal and
non-thermal components and find spatial trends of these parameters within the
nebula.


title: Monogamy of quantum entanglement in time

abstract:
  In this paper we state a fundamental question about the structure of
correlations in time and analyze temporal monogamy relations. We show that the
nature of temporal correlations is inherently different from the spatial ones
but in similarity to quantum spatial correlations, we expose a phenomenon of
monogamy of quantum entanglement in time. We perform this task applying the
entangled histories framework as a modifcation of the consistent histories
approach. These considerations are supported by introduction of necessary tools
specific for the tensor algebra used for representation of spatial
correlations. We show that Tsirelson bound on temporal Bell-like inequalities
can be derived from the entangled histories approach. Finally, we point out
that in a context of the tensor algebra used for linking states in different
times further studies on mathematical structure of the state representing
evolving systems are needed.


title:
Neutrino mixing and masses in SO(10) GUTs with hidden sector and flavor
  symmetries

abstract:
  We consider the neutrino masses and mixing in the framework of SO(10) GUTs
with hidden sector consisting of fermionic and bosonic SO(10) singlets and
flavor symmetries. The framework allows to disentangle the CKM physics
responsible for the CKM mixing and different mass hierarchies of quarks and
leptons and the neutrino new physics which produces smallness of neutrino
masses and large lepton mixing. The framework leads naturally to the relation
$U_{PMNS} \sim V_{CKM}^{\dagger} U_0$, where structure of $U_0$ is determined
by the flavor symmetry. The key feature of the framework is that apart from the
Dirac mass matrices $m_D$, the portal mass matrix $M_D$ and the mass matrix of
singlets $M_S$ are also involved in generation of the lepton mixing. This opens
up new possibilities to realize the flavor symmetries and explain the data.
Using $A_4 \times Z_4$ as the flavor group, we systematically explore the
flavor structures which can be obtained in this framework depending on field
content and symmetry assignments. We formulate additional conditions which lead
to $U_0 \sim U_{TBM}$ or $U_{BM}$. They include (i) equality (in general,
proportionality) of the singlet flavons couplings, (ii) equality of their VEVs;
(iii) correlation between VEVs of singlets and triplet, (iv) certain VEV
alignment of flavon triplet(s). These features can follow from additional
symmetries or be remnants of further unification. Phenomenologically viable
schemes with minimal flavon content and minimal number of couplings are
constructed.


title: H, He-like recombination spectra I: $l$-changing collisions for hydrogen

abstract:
  Hydrogen and helium emission lines in nebulae form by radiative
recombination. This is a simple process which, in principle, can be described
to very high precision. Ratios of He I and H I emission lines can be used to
measure the He$^+$/H$^+$ abundance ratio to the same precision as the
recombination rate coefficients. This paper investigates the controversy over
the correct theory to describe dipole $l$-changing collisions ($nl\rightarrow
nl'=l\pm 1$) between energy-degenerate states within an $n$-shell. The work of
Pengelly & Seaton (1964) has, for half-a-century, been considered the
definitive study which "solved" the problem. Recent work by Vrinceanu et
al.(2012) recommended the use of rate coefficients from a semi-classical
approximation which are nearly an order of magnitude smaller than those of
Pengelly & Seaton (1964), with the result that significantly higher densities
are needed for the $nl$ populations to come into local thermodynamic
equilibrium.
  Here, we compare predicted H~I emissivities from the two works and find
widespread differences, of up to $\approx 10$%. This far exceeds the 1%
precision required to obtain the primordial He/H abundance ratio from
observations so as to constrain Big Bang cosmologies. We recommend using the
rate coefficients of Pengelly & Seaton (1964) for $l$-changing collisions, to
describe the H recombination spectrum, based-on their quantum mechanical
representation of the long-range dipole interaction.

categories: astro-ph.GA astro-ph.CO astro-ph.SR physics.atom-ph


title:
Characterization of transiting exoplanets: analyzing the impact of the
  host star on the planet parameters

abstract:
  In this PhD dissertation, I discuss issues of the Radial Velocities (RV) and
transit methods. These techniques allow us to derive the mass and radius of an
exoplanet, necessary to model its bulk structure and to have insight on its
formation. To do this, however, also the same parameters of its host star are
needed. By using spectroscopy, I participated in TRANSITS, an RV follow-up
program of Kepler Objects of Interest. I determined the parameters of nine host
stars, enabling the characterization of their companions. With the same method,
I participated in two studies which aim at exploring the mass-radius
relationship of low-mass stars and at improving the statistics of star-planet
interactions. I also inspected the behavior of SOPHIE/OHP spectra for
instrumental effects which can affect the measure of the stellar parameters.
From a different perspective, I studied Kepler-117, a multi-planetary system
which presents Transit Timing Variations (TTV). A specific approach was
developed in order to realize a simultaneous fit of transits, RV, and TTV, used
to measure the mass of the lightest planet of the system, which was poorly
constrained by RV alone. Finally, I focused on the impact of stellar activity
in transit photometry and RV. This phenomenon affects the determination of the
planet radius and mass, as well as other key parameters. I implemented two
starspot modeling codes into a Markov Chain Monte Carlo software, and added
spot evolution to one of them. I applied the codes to observations of the Sun,
CoRoT-2, and CoRoT-7. In particular, I carried out an extensive study on the
light curve of CoRoT-2, and explored the effects of the spots on the transit
parameters. The planetary systems studied in this work provide further
constraints on models of planet interior and formation. With the techniques
here developed, they help in the preparation of future exoplanet surveys.


title: Connecting Through Obstruction; Relating Gauge Gravity and String Theory

abstract:
  We consider topological constraints that must be satisfied by formulations of
gravitation as a gauge theory. To facilitate the analysis we review and further
justify the composite bundle formalism of Tresguerres as a consistent
underlying structure capable of incorporating both the local Lorentz and
translational degrees of freedom. Identifying an important global structure
required by the composite construction, we translate this into conditions on
the underlying manifold. We find that in addition to admitting the expected
orientability, causality and spin structures, the underlying manifold must also
admit a string structure. We take this to imply that even before considerations
of quantum consistency, topological considerations of gauge gravity provide a
classical motivation for extended degrees of freedom.


title: RR Lyrae stars and the horizontal branch of NGC 5904 (M5)

abstract:
  We report the distance and [Fe/H] value for the globular cluster NGC 5904
(M5) derived from the Fourier decomposition of the light curves of selected
RRab and RRc stars. The aim in doing this was to bring these parameters into
the homogeneous scales established by our previous work on numerous other
globular clusters, allowing a direct comparison of the horizontal branch
luminosity in clusters with a wide range of metallicities. Our CCD photometry
of the large variable star population of this cluster is used to discuss light
curve peculiarities, like Blazhko modulations, on an individual basis. New
Blazhko variables are reported.
  From the RRab stars we found [Fe/H]$_{\rm UVES} = -1.335 \pm
0.003{\rm(statistical)} \pm 0.110{\rm(systematic)}$, and a distance of $7.6\pm
0.2$ kpc, and from the RRc stars we found [Fe/H]$_{\rm UVES}$ = $-1.39 \pm
0.03{\rm(statistical)} \pm 0.12{\rm(systematic)}$ and a distance of $7.5 \pm
0.3$ kpc. The results for RRab and RRc stars should be considered independent
since they come from different calibrations and zero points. Absolute
magnitudes, radii and masses are also reported for individual RR Lyrae stars.
The distance to the cluster was calculated by alternative methods like the P-L
relation of SX Phe and the luminosity of the stars at the tip of the red giant
branch; we obtained $7.7 \pm 0.4$ and $7.2-7.5$ kpc respectively.
  The distribution of RR Lyrae stars in the instability strip is discussed and
compared with other clusters in connection with the Oosterhoff and horizontal
branch type. The Oosterhoff type II clusters systematically show a RRab-RRc
segregation about the instability strip first-overtone red edge, while the
Oosterhoff type I clusters may or may not display this feature. A group of RR
Lyrae stars is identified in an advanced evolutionary stage, and two of them
are likely binaries with unseen companions.


title: Spin-Exchange Pumped NMR Gyros

abstract:
  We present the basic theory governing spin-exchange pumped NMR gyros. We
review the basic physics of spin-exchange collisions and relaxation as they
pertain to precision NMR. We present a simple model of operation as an NMR
oscillator and use it to analyze the dynamic response and noise properties of
the oscillator. We discuss the primary systematic errors (differential alkali
fields, quadrupole shifts, and offset drifts) that limit the bias stability,
and discuss methods to minimize them. We give with a brief overview of a
practical implementation and performance of an NMR gyro built by
Northrop-Grumman Corporation, and conclude with some comments about future
prospects.


title:
Constraining the ellipticity of strongly magnetized neutron stars
  powering superluminous supernovae

abstract:
  Superluminous supernovae (SLSNe) have been suggested to be powered by
strongly magnetized, rapidly rotating neutron stars which are often called
magnetars. In this process, rotational energy of the magnetar is radiated via
magnetic dipole radiation and heats the supernova ejecta. However, if magnetars
are highly distorted in their geometric shape, rotational energy is mainly lost
as gravitational wave radiation and thus such magnetars cannot power SLSNe. By
simply comparing electromagnetic and gravitational wave emission timescales, we
constrain upper limits to the ellipticity of magnetars by assuming that they
power the observed SLSNe. We find that their ellipticity typically needs to be
less than about a few 1e-3. This indicates that the toroidal magnetic field
strengths in these magnetars are typically less than a few 1e16 G so that their
distortions remain small. Because light-curve modelling of SLSNe shows that
their dipole magnetic field strengths are of the order of 1e14 G, the ratio of
poloidal to toroidal magnetic field strengths is found to be larger than ~ 0.01
in magnetars powering SLSNe.


title:
Predicting Lane Keeping Behavior of Visually Distracted Drivers Using
  Inverse Suboptimal Control

abstract:
  Driver distraction strongly contributes to crash-risk. Therefore, assistance
systems that warn the driver if her distraction poses a hazard to road safety,
promise a great safety benefit. Current approaches either seek to detect
critical situations using environmental sensors or estimate a driver's
attention state solely from her behavior. However, this neglects that driving
situation, driver deficiencies and compensation strategies altogether determine
the risk of an accident. This work proposes to use inverse suboptimal control
to predict these aspects in visually distracted lane keeping. In contrast to
other approaches, this allows a situation-dependent assessment of the risk
posed by distraction. Real traffic data of seven drivers are used for
evaluation of the predictive power of our approach. For comparison, a baseline
was built using established behavior models. In the evaluation our method
achieves a consistently lower prediction error over speed and track-topology
variations. Additionally, our approach generalizes better to driving speeds
unseen in training phase.


title:
Remarkable magnetostructural coupling around the magnetic transition in
  CeCo$_{0.85}$Fe$_{0.15}$Si

abstract:
  We report a detailed study of the magnetic properties of
CeCo$_{0.85}$Fe$_{0.15}$Si under high magnetic fields (up to 16 Tesla)
measuring different physical properties such as specific heat, magnetization,
electrical resistivity, thermal expansion and magnetostriction.
CeCo$_{0.85}$Fe$_{0.15}$Si becomes antiferromagnetic at $T_N \approx$ 6.7 K.
However, a broad tail (onset at $T_X \approx$ 13 K) in the specific heat
precedes that second order transition. This tail is also observed in the
temperature derivative of the resistivity. However, it is particularly
noticeable in the thermal expansion coefficient where it takes the form of a
large bump centered at $T_X$. A high magnetic field practically washes out that
tail in the resistivity. But surprisingly, the bump in the thermal expansion
becomes a well pronounced peak fully split from the magnetic transition at
$T_N$. Concurrently, the magnetoresistance also switches from negative to
positive just below $T_X$. The magnetostriction is considerable and
irreversible at low temperature ($\frac {\Delta L}{L} \left(16 T\right) \sim$
4$\times$10$^{-4}$ at 2 K) when the magnetic interactions dominate. A broad
jump in the field dependence of the magnetostriction observed at low $T$ may be
the signature of a weak ongoing metamagnetic transition. Taking altogether, the
results indicate the importance of the lattice effects in the development of
the magnetic order in these alloys.


title:
Theoretically-Grounded Policy Advice from Multiple Teachers in
  Reinforcement Learning Settings with Applications to Negative Transfer

abstract:
  Policy advice is a transfer learning method where a student agent is able to
learn faster via advice from a teacher. However, both this and other
reinforcement learning transfer methods have little theoretical analysis. This
paper formally defines a setting where multiple teacher agents can provide
advice to a student and introduces an algorithm to leverage both autonomous
exploration and teacher's advice. Our regret bounds justify the intuition that
good teachers help while bad teachers hurt. Using our formalization, we are
also able to quantify, for the first time, when negative transfer can occur
within such a reinforcement learning setting.


title: Tropical Igusa Invariants

abstract:
  Let $X$ be a smooth geometrically connected projective curve of genus two
over a complete non-archimedean field $K$. For discretely valued $K$, the first
main theorem in \cite{liu} gives a set of criteria on the Igusa invariants of
the curve that determine the minimal Berkovich skeleton of $X$ together with
its edge lengths and vertex weights. In this paper we use the theory of
Berkovich spaces to give a new proof of this theorem that works for arbitrary
complete non-archimedean fields. We furthermore interpret the final result in
terms of tropical moduli spaces and tropical Igusa invariants. This
reformulation shows that the abstract tropicalization map
${M}_{2}\to\mathrm{trop}(M_{2})$ factors through the tropicalization of a
concrete embedding of ${M}_{2}$ into a weighted projective space.


title: Geometric Defects in Quantum Hall States

abstract:
  We describe a geometric (or gravitational) analogue of the Laughlin
quasiholes in the fractional quantum Hall states. Analogously to the quasiholes
these defects can be constructed by an insertion of an appropriate vertex
operator into the conformal block representation of a trial wavefunction,
however, unlike the quasiholes these defects are extrinsic and do not
correspond to true excitations of the quantum fluid. We construct a
wavefunction in the presence of such defects and explain how to assign an
electric charge and a spin to each defect, and calculate the adiabatic,
non-abelian statistics of the defects. The defects turn out to be equivalent to
the genons in that their adiabatic exchange statistics can be described in
terms of representations of the mapping class group of an appropriate higher
genus Riemann surface. We present a general construction that, in principle,
allows to calculate the statistics of $\mathbb Z_n$ genons for any "parent"
topological phase. We illustrate the construction on the example of the
Laughlin state and perform an explicit calculation of the braiding matrices. In
addition to non-abelian statistics geometric defects possess a universal
abelian overall phase, determined by the gravitational anomaly.


title: Synthesis of Polar Ordered Oxynitride Perovskite

abstract:
  For decades, numerous attempts have been made to produce polar oxynitride
perovskites, where some of the oxygen are replaced by nitrogen, but a polar
ordered oxynitride has never been demonstrated. Caracas and Cohen studied
possible ordered polar oxynitrides within density functional theory (DFT) and
found a few candidates that were predicted to be insulating and at least
metastable. YSiO2N stood out with huge predicted polarization and nonlinear
optic coefficients. In this study, we demonstrate the synthesis of
perovskite-structured YSiO2N by using a combination of a diamond anvil cell and
in-situ laser heating technique. Subsequent in-situ X-ray diffraction, second
harmonic generation, and Raman scattering measurements confirm that it is polar
and a strong nonlinear optical material, with structure and properties similar
to those predicted by DFT.


title: Generalized Gibbs ensemble in integrable lattice models

abstract:
  The generalized Gibbs ensemble (GGE) was introduced ten years ago to describe
observables in isolated integrable quantum systems after equilibration. Since
then, the GGE has been demonstrated to be a powerful tool to predict the
outcome of the relaxation dynamics of few-body observables in a variety of
integrable models, a process we call generalized thermalization. This review
discusses several fundamental aspects of the GGE and generalized thermalization
in integrable systems. In particular, we focus on questions such as: which
observables equilibrate to the GGE predictions and who should play the role of
the bath; what conserved quantities can be used to construct the GGE; what are
the differences between generalized thermalization in noninteracting systems
and in interacting systems mappable to noninteracting ones; why is it that the
GGE works when traditional ensembles of statistical mechanics fail. Despite a
lot of interest in these questions in recent years, no definite answers have
been given. We review results for the XX model and for the transverse field
Ising model. For the latter model, we also report original results and show
that the GGE describes spin-spin correlations over the entire system. This
makes apparent that there is no need to trace out a part of the system in real
space for equilibration to occur and for the GGE to apply. In the past, a
spectral decomposition of the weights of various statistical ensembles revealed
that generalized eigenstate thermalization occurs in the XX model (hard-core
bosons). Namely, eigenstates of the Hamiltonian with similar distributions of
conserved quantities have similar expectation values of few-spin observables.
Here we show that generalized eigenstate thermalization also occurs in the
transverse field Ising model.

categories: cond-mat.stat-mech cond-mat.quant-gas cond-mat.str-el quant-ph


title:
Prediction and real-time compensation of qubit decoherence via
  machine-learning

abstract:
  The wide-ranging adoption of quantum technologies requires practical,
high-performance advances in our ability to maintain quantum coherence while
facing the challenge of state collapse under measurement. Here we use
techniques from control theory and machine learning to predict the future
evolution of a qubit's state; we deploy this information to suppress
stochastic, semiclassical decoherence, even when access to measurements is
limited. First, we implement a time-division-multiplexed approach, interleaving
measurement periods with periods of unsupervised but stabilised operation
during which qubits are available, for e.g. quantum information experiments.
Second, we employ predictive feedback during sequential but time delayed
measurements to reduce the Dick effect as encountered in passive frequency
standards. Both experiments demonstrate significant improvements in qubit phase
stability over "traditional" measurement-based feedback approaches by
exploiting time domain correlations in the noise processes. This technique
requires no additional hardware and is applicable to all two-level quantum
systems where projective measurements are possible.


title: Instability Mechanism for STT-MRAM switching

abstract:
  To optimize the design of STT-MRAM (spin-transfer torque magnetic random
access memory), it is necessary to be able to predict switching (error) rates.
For small elements, this can be done using a single-macrospin theory since the
element will switch quasi-uniformly. Experimental results on switching rates
suggest that elements large enough to be thermally stable switch by some
mechanism with a lower energy barrier. It has been suggested that this
mechanism is local nucleation, but we have also previously reported a global
magnetostatic instability, which is consistent with the lower experimental
energy barriers. In this paper, we try to determine which of these mechanisms
is most important by visualizing the switching in a "U-NU" (uniform -
nonuniform) phase diagram. We find that switching trajectories follow the
horizontal U axis (i.e., quasi-uniform precession) until they reach a critical
amplitude, at which the magnetostatic instability grows exponentially and a
domain wall forms at the center, whose motion completes the switching. We have
tried unsuccessfully to induce local nucleation (a domain wall at the edge). We
conclude that the dominant switching mechanism is not edge nucleation, but the
magnetostatic instability.


title: Consistency of modularity clustering on random geometric graphs

abstract:
  We consider a large class of random geometric graphs constructed from samples
$\mathcal{X}_n = \{X_1,X_2,\ldots,X_n\}$ of independent, identically
distributed observations of an underlying probability measure $\nu$ on a
bounded domain $D\subset \mathbb{R}^d$. The popular `modularity' clustering
method specifies a partition $\mathcal{U}_n$ of the set $\mathcal{X}_n$ as the
solution of an optimization problem. In this paper, under conditions on $\nu$
and $D$, we derive scaling limits of the modularity clustering on random
geometric graphs. Among other results, we show a geometric form of consistency:
When the number of clusters is a priori bounded above, the discrete optimal
partitions $\mathcal{U}_n$ converge in a certain sense to a continuum partition
$\mathcal{U}$ of the underlying domain $D$, characterized as the solution of a
type of Kelvin's shape optimization problem.


title:
Ionized gas kinematics within the inner kiloparsec of the Seyfert galaxy
  NGC 1365

abstract:
  We observed the nuclear region of the galaxy NGC 1365 with the integral field
unit of the Gemini Multi Object Spectrograph mounted on the GEMINI-South
telescope. The field of view covers $13^{\prime\prime} \times 6^{\prime\prime}$
($1173 \times 541$ pc$^{2}$) centered on the nucleus, at a spatial resolution
of $52$ pc. The spectral coverage extends from $5600$ \AA\ to $7000$ \AA, at a
spectral resolution $R=1918$. NGC 1365 hosts a Seyfert 1.8 nucleus, and
exhibits a prominent bar extending out to $100^{\prime\prime}$ (9 kpc) from the
nucleus. The field of view lies within the inner Lindblad resonance. Within
this region, we found that the kinematics of the ionized gas (as traced by
[OI], [NII], H$\alpha$, and [SII]) is consistent with rotation in the
large-scale plane of the galaxy. While rotation dominates the kinematics, there
is also evidence for a fan-shaped outflow, as found in other studies based on
the [OIII] emission lines. Although evidence for gas inflowing along nuclear
spirals has been found in a few barred galaxies, we find no obvious signs of
such features in the inner kiloparsec of NGC 1365. However, the emission lines
exhibit a puzzling asymmetry that could originate from gas which is slower than
the gas responsible for the bulk of the narrow-line emission. We speculate that
it could be tracing gas which lost angular momentum, and is slowly migrating
from the inner Lindblad resonance towards the nucleus of the galaxy.


title:
Concentration Fluctuations and Capacitive Response in Dense Ionic
  Solutions

abstract:
  We use molecular dynamics simulations in a constant potential ensemble to
study the effects of solution composition on the electrochemical response of a
double layer capacitor. We find that the capacitance first increases with ion
concentration following its expected ideal solution behavior, but decreases
upon approaching a pure ionic liquid in agreement with recent experimental
observations. The non-monotonic behavior of the capacitance as a function of
ion concentration results from the competition between the independent motion
of solvated ions in the dilute regime and solvation fluctuations in the
concentrated regime. Mirroring the capacitance, we find that the characteristic
decay length of charge density correlations away from the electrode is also
non-monotonic. The correlation length first decreases with ion concentration as
a result of better electrostatic screening but increases with ion concentration
as a result of enhanced steric interactions. When charge fluctuations induced
by correlated ion-solvent fluctuations are large relative to those induced by
the pure ionic liquid, such capacitive behavior is expected to be generic.


title: Evidence of Self-Organization in Time Series of Capital Markets

abstract:
  A methodology is developed to identify, as units of study, each decrease in
the value of a stock from a given maximum price level. A critical level in the
amount of price declines is found to separate a segment operating under a
random walk from a segment operating under a power law. This level is
interpreted as a point of phase transition into a self-organized system.
Evidence of self-organization was found in all the stock market indices studied
but in none of the control synthetic random series. Findings partially explain
the fractal structure characteristic of financial time series and suggest that
price fluctuations adopt two different operating regimes. We propose to
identify downward movements larger than the critical level apparently subject
to the power law, as self-organized states, and price decreases smaller than
the critical level, as a random walk with the Markov property.


title: A Minkowski theorem for Meyer sets

abstract:
  In this paper, we generalize Minkowski's theorem. This theorem is usually
stated for a centrally symmetric convex body and a lattice both included in
$\mathbb{R}^n$. In some situations, one may replace the lattice by a more
general set for which a notion of density exists. In this paper, we prove a
Minkowski theorem for Meyer sets, which bounds from below the frequency of
differences appearing in the Meyer set and belonging to a centrally symmetric
convex body. In the later part of the paper, we develop quite natural
applications of this theorem to Diophantine approximation and to discretization
of linear maps.


title: Qubit and Fermionic Fock Spaces from Type II Superstring Black Holes

abstract:
  Using Hodge diagram combinatorial data, we study qubit and fermionic Fock
spaces from the point of view of type II superstring black holes based on
complex compactifications. Concretely, we establish a one-to-one correspondence
between qubits, fermionic spaces and extremal black holes in maximally
supersymmetric supergravity obtained from type II superstring on complex
toroidal and Calabi-Yau compactifications. We interpret the differential forms
of the n-dimensional complex toroidal compactification as states of n-qubits
encoding information on extremal black hole charges. We show that there are 2^n
copies of n-qubit systems which can be split as 2^n=2^{n-1}+2^{n-1}. More
precisely, 2^{n-1} copies are associated with even D-brane charges in type IIA
superstring and the other 2^{n-1} ones correspond to odd D-brane charges in IIB
superstring. This correspondence is generalized to a class of Calabi-Yau
manifolds. In connection with black hole charges in type IIA superstring, an
n-qubit system has been obtained from a canonical line bundle of n factors of
one dimensional projective space \mathbb{CP}^1.


title: Products in a Category with One Object

abstract:
  We study monoids equipped with a second binary operation that captures the
structure of the endomorphisms of an object $X$ such that $X=X\times X$. We
construct a universal monoid of this type and examine some of its rich
combinatorial structure. We show that if $X$ has a nontrivial endomorphism and
$X=X\times X$, then every finite monoid has a faithful action on $X$.


title: Sequestering effects on and of vacuum decay

abstract:
  We consider phase transitions and their contributions to vacuum energy in the
manifestly local theory of vacuum energy sequestering. We demonstrate that the
absence of instabilities imposes constraints on the couplings of gravitating
and non-gravitating sectors, which can be satisfied in a large class of models.
We further show by explicit construction that the vacuum energy contributions
to the effective cosmological constant in the descendant vacua are generically
strongly suppressed by the ratios of spacetime volumes of parent and descendant
geometries. This means that the cosmological constant in de Sitter descendant
vacua remains insensitive to phase transitions which may have occurred in the
course of its cosmic history.


title:
Constraining cosmological ultra-large scale structure using numerical
  relativity

abstract:
  Cosmic inflation, a period of accelerated expansion in the early universe,
can give rise to large amplitude ultra-large scale inhomogeneities on distance
scales comparable to or larger than the observable universe. The cosmic
microwave background (CMB) anisotropy on the largest angular scales is
sensitive to such inhomogeneities and can be used to constrain the presence of
ultra-large scale structure (ULSS). We numerically evolve nonlinear
inhomogeneities present at the beginning of inflation in full General
Relativity to assess the CMB quadrupole constraint on the amplitude of the
initial fluctuations and the size of the observable universe relative to a
length scale characterizing the ULSS. To obtain a statistically significant
number of simulations, we adopt a toy model in which inhomogeneities are
injected along a preferred direction. We compute the likelihood function for
the CMB quadrupole including both ULSS and the standard quantum fluctuations
produced during inflation. We compute the posterior given the observed CMB
quadrupole, finding that when including gravitational nonlinearities, ULSS
curvature perturbations of order unity are allowed by the data, even on length
scales not too much larger than the size of the observable universe. Our
results illustrate the utility and importance of numerical relativity for
constraining early universe cosmology.


title:
Sparse transition matrix estimation for high-dimensional and locally
  stationary vector autoregressive models

abstract:
  We consider the estimation of the transition matrix in the high-dimensional
time-varying vector autoregression (TV-VAR) models. Our model builds on a
general class of locally stationary VAR processes that evolve smoothly in time.
We propose a hybridized kernel smoothing and $\ell^1$-regularized method to
directly estimate the sequence of time-varying transition matrices. Under the
sparsity assumption on the transition matrix, we establish the rate of
convergence of the proposed estimator and show that the convergence rate
depends on the smoothness of the locally stationary VAR processes only through
the smoothness of the transition matrix function. In addition, for our
estimator followed by thresholding, we prove that the false positive rate (type
I error) and false negative rate (type II error) in the pattern recovery can
asymptotically vanish in the presence of weak signals without assuming the
minimum nonzero signal strength condition. Favorable finite sample performances
over the $\ell^2$-penalized least-squares estimator and the unstructured
maximum likelihood estimator are shown on simulated data. We also provide two
real examples on estimating the dependence structures on financial stock prices
and economic exchange rates datasets.


title:
Non-standard cohomology for equivariant sheaves: The role of generic
  models

abstract:
  We generalize the Generic Model Theorem for equivariant presheaves of
structures; extending the results of Macintyre and Caicedo. We also introduce a
new class of generic cohomologies and show how, for some examples, they
simplify to non standard cohomologies.
  Key words and phrases: Generic Model Theorem, Equivariant Structures,
Equivariant Cohomology.
  Primary fields: Model Theory. Equivariant sheaf cohomology.


title: Understanding How Image Quality Affects Deep Neural Networks

abstract:
  Image quality is an important practical challenge that is often overlooked in
the design of machine vision systems. Commonly, machine vision systems are
trained and tested on high quality image datasets, yet in practical
applications the input images can not be assumed to be of high quality.
Recently, deep neural networks have obtained state-of-the-art performance on
many machine vision tasks. In this paper we provide an evaluation of 4
state-of-the-art deep neural network models for image classification under
quality distortions. We consider five types of quality distortions: blur,
noise, contrast, JPEG, and JPEG2000 compression. We show that the existing
networks are susceptible to these quality distortions, particularly to blur and
noise. These results enable future work in developing deep neural networks that
are more invariant to quality distortions.


title: Free topological vector spaces

abstract:
  We define and study the free topological vector space $\mathbb{V}(X)$ over a
Tychonoff space $X$. We prove that $\mathbb{V}(X)$ is a $k_\omega$-space if and
only if $X$ is a $k_\omega$-space. If $X$ is infinite, then $\mathbb{V}(X)$
contains a closed vector subspace which is topologically isomorphic to
$\mathbb{V}(\mathbb{N})$. It is proved that if $X$ is a $k$-space, then
$\mathbb{V}(X)$ is locally convex if and only if $X$ is discrete and countable.
If $X$ is a metrizable space it is shown that: (1) $\mathbb{V}(X)$ has
countable tightness if and only if $X$ is separable, and (2) $\mathbb{V}(X)$ is
a $k$-space if and only if $X$ is locally compact and separable. It is proved
that $\mathbb{V}(X)$ is a barrelled topological vector space if and only if $X$
is discrete. This result is applied to free locally convex spaces $L(X)$ over a
Tychonoff space $X$ by showing that: (1) $L(X)$ is quasibarrelled if and only
if $L(X)$ is barrelled if and only if $X$ is discrete, and (2) $L(X)$ is a
Baire space if and only if $X$ is finite.