title:
GeoClaw-STRICHE: A coupled model for Sediment TRansport In Coastal
  Hazard Events

abstract:
  GeoClaw-STRICHE is designed for simulating the physical impacts of tsunami as
it relates to erosion, transport and deposition. GeoClaw-STRICHE comprises of
three components: (1) nonlinear shallow water equations; (2)
advection-diffusion equation; (3) an equation for morphology updating. Multiple
grain sizes and sediment layers are added into GeoClaw-STRICHE to simulate
grain-size distribution and add the capability to develop grain-size trends
from bottom to the top of a simulated deposit as well as along the inundation.
Unlike previous models based on empirical equations or sediment concentration
gradient, the standard Van Leer method is applied to calculate sediment flux.
We tested and verified GeoClaw-STRICHE with flume experiment by
\citet{johnson2016experimental} and data from the 2004 Indian Ocean tsunami in
Kuala Meurisi as published in \citet{JGRF:JGRF786}. The comparison with
experimental data shows GeoClaw-STRICHE's capability to simulate sediment
thickness and grain-size distribution in experimental conditions. The agreement
between experimental and model results is generally quite good, especially for
sediment thickness, which builds confidence that sediment transport is
correctly predicted by this model. The comparison with the data from the 2004
Indian Ocean tsunami reveals that the pattern of sediment thickness is well
predicted and is of similar quality, if not better than the established
computational models such as Delft3D.


title: Special functions and twisted $L$-series

abstract:
  We introduce a generalization of the Anderson-Thakur special function, and we
prove a rationality result for several variable twisted $L$-series associated
to shtuka functions.


title:
Professional and Citizen Bibliometrics: Complementarities and
  ambivalences in the development and use of indicators

abstract:
  Bibliometric indicators such as journal impact factors, h-indices, and total
citation counts are algorithmic artifacts that can be used in research
evaluation and management. These artifacts have no meaning by themselves, but
receive their meaning from attributions in institutional practices. We
distinguish four main stakeholders in these practices: (1) producers of
bibliometric data and indicators; (2) bibliometricians who develop and test
indicators; (3) research managers who apply the indicators; and (4) the
scientists being evaluated with potentially competing career interests. These
different positions may lead to different and sometimes conflicting
perspectives on the meaning and value of the indicators. The indicators can
thus be considered as boundary objects which are socially constructed in
translations among these perspectives. This paper proposes an analytical
clarification by listing an informed set of (sometimes unsolved) problems in
bibliometrics which can also shed light on the tension between simple but
invalid indicators that are widely used (e.g., the h-index) and more
sophisticated indicators that are not used or cannot be used in evaluation
practices because they are not transparent for users, cannot be calculated, or
are difficult to interpret.


title: Semantics for UGV Registration in GPS-denied Environments

abstract:
  Localization in a global map is critical to success in many autonomous robot
missions. This is particularly challenging for multi-robot operations in
unknown and adverse environments. Here, we are concerned with providing a small
unmanned ground vehicle (UGV) the ability to localize itself within a 2.5D
aerial map generated from imagery captured by a low-flying unmanned aerial
vehicle (UAV). We consider the scenario where GPS is unavailable and
appearance-based scene changes may have occurred between the UAV's flight and
the start of the UGV's mission. We present a GPS-free solution to this
localization problem that is robust to appearance shifts by exploiting
high-level, semantic representations of image and depth data. Using data
gathered at an urban test site, we empirically demonstrate that our technique
yields results within five meters of a GPS-based approach.


title: Further Exploration of Riemann's Functional Equation

abstract:
  A previous exploration of the Riemann functional equation that focussed on
the critical line, is extended over the complex plane. Significant results
include a simpler derivation of the fundamental equation developed previously,
and its generalization from the critical line to the complex plane. A simpler
statement of the relationship that exists between the real and imaginary
components of $\zeta(s)$ and $\zeta^{\prime}(s)$ on opposing sides of the
critical line is developed, reducing to a simpler statement of the same result
on the critical line. An analytic expression is obtained for the sum of the
arguments of $\zeta(s)$ on opposite sides of the critical line, reducing to the
analytic expression for $arg(\zeta(1/2+i\rho))$ first obtained in the previous
work. Relationships are obtained between various combinations of $|\zeta(s)|$
and $|\zeta^{\prime}(s)|$, particularly on the critical line, and it is
demonstrated that $arg(\zeta(1/2+i\rho))$ and $arg(\zeta^{\prime}(1/2+i\rho))$
uniquely define $|\zeta(1/2+i\rho)|$. A comment is made about the utility of
such results as they might apply to putative proofs of Riemann's Hypothesis
(RH).


title:
Statistical signatures of states orthogonal to the Fock-state ladder of
  composite bosons

abstract:
  The theory of composite bosons (cobosons) made of two fermions [Phys. Rev. A
71, 034306 (2005), Phys. Rev. Lett. 109, 260403 (2012)] converges to ordinary
structureless bosons in the limit of infinitely strong entanglement between the
fermionic constituents. For finite entanglement, the annihilation operator
$\hat c$ of a composite boson couples the $N$-coboson Fock-state not only to
the $(N-1)$-coboson state -- as for ordinary bosons --, but also to a component
which is orthogonal to the Fock-state ladder of cobosons. Coupling with states
orthogonal to the Fock ladder arises also in dynamical processes of cobosons.
Here, with a Gedanken-experiment involving both mode-splitting and collective
Hong-Ou-Mandel-like interference, we derive the characteristic physical
signature of the states orthogonal to the Fock ladder generated in the
splitting process. This allows to extract microscopic properties of
many-fermion-wave functions from the collective coboson behavior. We show that
consecutive beam-splitter dynamics increases the deviation from the ideal
bosonic behavior pattern, which opens up a rigorous approach to the
falsification of coboson theory.


title: On the spectrum for the genera of maximal curves over small fields

abstract:
  Motivated by previous computations in Garcia, Stichtenoth and Xing (2000)
paper ,we discuss the spectrum $\mathbf{M}(q^2)$ for the genera of maximal
curves over finite fields of order $q^2$ with $7\leq q\leq 16$. In particular,
by using a result in Kudo and Harashita(2016) paper, the set $\mathbf{M}(7^2)$
is completely determined.


title: Super-Earths as Failed Cores in Orbital Migration Traps

abstract:
  We explore whether close-in super-Earths were formed as rocky bodies that
failed to grow fast enough to become the cores of gas giants before the natal
protostellar disk dispersed. We model the failed cores' inward orbital
migration in the low-mass or type I regime, to stopping points at distances
where the tidal interaction with the protostellar disk applies zero net torque.
The three kinds of migration traps considered are those due to the dead zone's
outer edge, the ice line, and the transition from accretion to starlight as the
disk's main heat source. As the disk disperses, the traps move toward final
positions near or just outside 1~au. Planets at this location exceeding about
3~M$_\oplus$ open a gap, decouple from their host trap, and migrate inward in
the high-mass or type II regime to reach the vicinity of the star. We
synthesize the population of planets formed in this scenario, finding that some
fraction of the observed super-Earths can be failed cores. Most super-Earths
formed this way have more than 4~M$_\oplus$, so their orbits when the disk
disperses are governed by type II migration. These planets have solid cores
surrounded by gaseous envelopes. Their subsequent photoevaporative mass loss is
most effective for masses originally below about 6 M$_\oplus$. The failed core
scenario suggests a division of the observed super-Earth mass-radius diagram
into five zones according to the inferred formation history.


title: Non-simple SLE curves are not determined by their range

abstract:
  We show that when observing the range of a chordal SLE$_\kappa$ curve for
$\kappa \in (4,8)$, it is not possible to recover the order in which the points
have been visited. We also derive related results about conformal loop
ensembles (CLE): (i) The loops in a CLE$_\kappa$ for $\kappa \in (4,8)$ are not
determined by the CLE$_\kappa$ gasket. (ii) The continuum percolation
interfaces defined in the fractal carpets of conformal loop ensembles
CLE$_{\kappa}$ for $\kappa \in (8/3, 4)$ (we defined these percolation
interfaces in previous work, and showed there that they are SLE$_{16/\kappa}$
curves) are not determined by the CLE$_{\kappa}$ carpet that they are defined
in.


title:
Synthetic dimensions and spin-orbit coupling with an optical clock
  transition

abstract:
  We demonstrate a novel way of synthesizing spin-orbit interactions in
ultracold quantum gases, based on a single-photon optical clock transition
coupling two long-lived electronic states of two-electron $^{173}$Yb atoms. By
mapping the electronic states onto effective sites along a synthetic
"electronic" dimension, we have engineered synthetic fermionic ladders with
tunable magnetic fluxes. We have detected the spin-orbit coupling with
fiber-link-enhanced clock spectroscopy and directly measured the emergence of
chiral edge currents, probing them as a function of the magnetic field flux.
These results open new directions for the investigation of topological states
of matter with ultracold atomic gases.


title:
Bernstein-Sato polynomials for projective hypersurfaces with weighted
  homogeneous isolated singularities

abstract:
  We present a quite efficient method to compute the roots of Bernstein-Sato
polynomial of a homogeneous polynomial if the associated projective
hypersurface has only weighted homogeneous isolated singularities (so that its
local Bernstein-Sato polynomials are uniquely determined by weights) and if a
certain condition is satisfied. In the three variable case, the last condition
holds except for polynomials of quite special type (that is, extremely
degenerated ones) as far as calculated. The computation of roots is reduced to
that of the Hilbert series of graded Milnor algebras, which can be done
instantly by computers (unless the degree is huge), although it takes much
longer to get the Bernstein-Sato polynomial itself (that is, with
multiplicities) using a computer program in general. For the proof of the
formula, we prove the $E_2$-degeneration of the pole order spectral sequence.
There is a formula showing the discrete connectivity of the roots of
Bernstein-Sato polynomials supported at 0, if the projective hypersurfaces have
only ordinary double points or the Tjurina number is relatively small.


title:
Photo-Realistic Single Image Super-Resolution Using a Generative
  Adversarial Network

abstract:
  Despite the breakthroughs in accuracy and speed of single image
super-resolution using faster and deeper convolutional neural networks, one
central problem remains largely unsolved: how do we recover the finer texture
details when we super-resolve at large upscaling factors? The behavior of
optimization-based super-resolution methods is principally driven by the choice
of the objective function. Recent work has largely focused on minimizing the
mean squared reconstruction error. The resulting estimates have high peak
signal-to-noise ratios, but they are often lacking high-frequency details and
are perceptually unsatisfying in the sense that they fail to match the fidelity
expected at the higher resolution. In this paper, we present SRGAN, a
generative adversarial network (GAN) for image super-resolution (SR). To our
knowledge, it is the first framework capable of inferring photo-realistic
natural images for 4x upscaling factors. To achieve this, we propose a
perceptual loss function which consists of an adversarial loss and a content
loss. The adversarial loss pushes our solution to the natural image manifold
using a discriminator network that is trained to differentiate between the
super-resolved images and original photo-realistic images. In addition, we use
a content loss motivated by perceptual similarity instead of similarity in
pixel space. Our deep residual network is able to recover photo-realistic
textures from heavily downsampled images on public benchmarks. An extensive
mean-opinion-score (MOS) test shows hugely significant gains in perceptual
quality using SRGAN. The MOS scores obtained with SRGAN are closer to those of
the original high-resolution images than to those obtained with any
state-of-the-art method.


title:
Hydrodynamization in kinetic theory: Transient modes and the gradient
  expansion

abstract:
  We explore the transition to hydrodynamics in a weakly-coupled model of
quark-gluon plasma given by kinetic theory in the relaxation time approximation
with conformal symmetry. We demonstrate that the gradient expansion in this
model has a vanishing radius of convergence due to the presence of a transient
(nonhydrodynamic) mode, in a way similar to results obtained earlier in
strongly-coupled gauge theories. This suggests that the mechanism by which
hydrodynamic behaviour emerges is the same, which we further corroborate by a
novel comparison between solutions of different weakly and strongly coupled
models. However, in contrast with other known cases, we find that not all the
singularities of the analytic continuation of the Borel transform of the
gradient expansion correspond to transient excitations of the microscopic
system: some of them reflect analytic properties of the kinetic equation when
the proper time is continued to complex values.


title:
Cloud Atlas: Discovery of Patchy Clouds and High-amplitude Rotational
  Modulations In a Young, Extremely Red L-type Brown Dwarf

abstract:
  Condensate clouds fundamentally impact the atmospheric structure and spectra
of exoplanets and brown dwarfs but the connections between surface gravity,
cloud structure, dust in the upper atmosphere, and the red colors of some brown
dwarfs remain poorly understood. Rotational modulations enable the study of
different clouds in the same atmosphere, thereby providing a method to isolate
the effects of clouds. Here we present the discovery of high peak-to-peak
amplitude (8%) rotational modulations in a low-gravity, extremely red
(J-Ks=2.55) L6 dwarf WISEP J004701.06+680352.1 (W0047). Using the Hubble Space
Telescope (HST) time-resolved grism spectroscopy we find a best-fit rotational
period (13.20$\pm$0.14 hours) with a larger amplitude at 1.1 micron than at 1.7
micron. This is the third largest near-infrared variability amplitude measured
in a brown dwarf, demonstrating that large-amplitude variations are not limited
to the L/T transition but are present in some extremely red L-type dwarfs. We
report a tentative trend between the wavelength dependence of relative
amplitude, possibly proxy for small dust grains lofted in the upper atmosphere,
and the likelihood of large-amplitude variability. By assuming forsterite as
haze particle, we successfully explain the wavelength dependent amplitude with
submicron-sized haze particles sizes of around 0.4 {\mu}m. W0047 links the
earlier spectral and later spectral type brown dwarfs in which rotational
modulations have been observed, the large amplitude variations in this object
make this a benchmark brown dwarf for the study of cloud properties close to
the L/T transition.


title: The quenching time scale and quenching rate of galaxies

abstract:
  The average star formation rate (SFR) in galaxies has been declining since
redshift of 2. A fraction of galaxies quench and become quiescent. We constrain
two key properties of the quenching process: the quenching time scale and the
quenching rate among galaxies. We achieve this by analyzing the galaxy number
density profile in NUV-u color space and the distribution in NUV-u v.s. u-i
color-color diagram with a simple toy-model framework. We focus on galaxies in
three mass bins between 10 to 10 and 10 to 10.6 solar mass. In the NUV-u v.s.
u-i color-color diagram, the red u-i galaxies exhibit a different slope from
the slope traced by the star-forming galaxies. This angled distribution and the
number density profile of galaxies in NUV-u space strongly suggest that the
decline of the SFR in galaxies has to accelerate before they turn quiescent. We
model this color-color distribution with a two-phase exponential decline star
formation history. The models with an e-folding time in the second phase (the
quenching phase) of 0.5 Gyr best fit the data. We further use the NUV-u number
density profile to constrain the quenching rate among star-forming galaxies as
a function of mass. Adopting an e-folding time of 0.5 Gyr in the second phase
(or the quenching phase), we found the quenching rate to be 19%/Gyr, 25%/Gyr
and 33%/Gyr for the three mass bins. These are upper limits of quenching rate
as the transition zone could also be populated by rejuvenated red-sequence
galaxies.


title:
On entanglement entropy in non-Abelian lattice gauge theory and 3D
  quantum gravity

abstract:
  Entanglement entropy is a valuable tool for characterizing the correlation
structure of quantum field theories. When applied to gauge theories, subtleties
arise which prevent the factorization of the Hilbert space underlying the
notion of entanglement entropy. Borrowing techniques from extended topological
field theories, we introduce a new definition of entanglement entropy for both
Abelian and non-Abelian gauge theories. Being based on the notion of
excitations, it provides a completely relational way of defining regions.
Therefore, it naturally applies to background independent theories, e.g.
gravity, by circumventing the difficulty of specifying the position of the
entangling surface. We relate our construction to earlier proposals and argue
that it brings these closer to each other. In particular, it yields the
non-Abelian analogue of the "magnetic centre choice", as obtained through an
extended-Hilbert-space method, but applied to the recently introduced fusion
basis for 3D lattice gauge theories. We point out that the different
definitions of entanglement theory can be related to a choice of (squeezed)
vacuum state.


title: On two problems of Carlitz and their generalizations

abstract:
  Let $N_q$ be the number of solutions to the equation $$
(a_1^{}x_1^{m_1}+\dots+a_n^{}x_n^{m_n})^k=bx_1^{k_1}\cdots x_n^{k_n} $$ over
the finite field $\mathbb F_q=\mathbb F_{p^s}$. Carlitz found formulas
for~$N_q$ when $k_1=\dots=k_n=m_1=\dots=m_n=1$, $k=2$, $n=3$ or $4$, $p>2$; and
when ${m_1=\dots=m_n=2}$, $k=k_1=\dots=k_n=1$, $n=3$ or $4$, $p>2$. In earlier
papers, we studied the above equation with $k_1=\dots=k_n=1$ and obtained some
generalizations of Carlitz's results. Recently, Pan, Zhao and Cao considered
the case of arbitrary positive integers $k_1,\dots,k_n$ and proved the formula
$N_q=q^{n-1}+(-1)^{n-1}$, provided that $\gcd(\sum_{j=1}^n (k_jm_1\cdots
m_n/m_j)-km_1\cdots m_n,q-1)=1$. In this chapter, we determine $N_q$ explicitly
in some other cases.


title:
NuSTAR observations of WISE J1036+0449, a Galaxy at z$\sim1$ obscured by
  hot dust

abstract:
  Hot, Dust-Obscured Galaxies (Hot DOGs), selected from the WISE all sky
infrared survey, host some of the most powerful Active Galactic Nuclei (AGN)
known, and might represent an important stage in the evolution of galaxies.
Most known Hot DOGs are at $z> 1.5$, due in part to a strong bias against
identifying them at lower redshift related to the selection criteria. We
present a new selection method that identifies 153 Hot DOG candidates at $z\sim
1$, where they are significantly brighter and easier to study. We validate this
approach by measuring a redshift $z=1.009$, and an SED similar to higher
redshift Hot DOGs for one of these objects, WISE J1036+0449
($L_{\rm\,Bol}\simeq 8\times 10^{46}\rm\,erg\,s^{-1}$), using data from
Keck/LRIS and NIRSPEC, SDSS, and CSO. We find evidence of a broadened component
in MgII, which, if due to the gravitational potential of the supermassive black
hole, would imply a black hole mass of $M_{\rm\,BH}\simeq 2 \times 10^8
M_{\odot}$, and an Eddington ratio of $\lambda_{\rm\,Edd}\simeq 2.7$. WISE
J1036+0449 is the first Hot DOG detected by NuSTAR, and the observations show
that the source is heavily obscured, with a column density of
$N_{\rm\,H}\simeq(2-15)\times10^{23}\rm\,cm^{-2}$. The source has an intrinsic
2-10 keV luminosity of $\sim 6\times 10^{44}\rm\,erg\,s^{-1}$, a value
significantly lower than that expected from the mid-infrared/X-ray correlation.
We also find that the other Hot DOGs observed by X-ray facilities show a
similar deficiency of X-ray flux. We discuss the origin of the X-ray weakness
and the absorption properties of Hot DOGs. Hot DOGs at $z\lesssim1$ could be
excellent laboratories to probe the characteristics of the accretion flow and
of the X-ray emitting plasma at extreme values of the Eddington ratio.


title:
An object oriented parallel finite element scheme for computations of
  PDEs: Design and implementation

abstract:
  Parallel finite element algorithms based on object-oriented concepts are
presented. Moreover, the design and implementation of a data structure proposed
are utilized in realizing a parallel geometric multigrid method. The
ParFEMapper and the ParFECommunicator are the key components of the data
structure in the proposed parallel scheme. These classes are constructed based
on the type of finite elements (continuous or nonconforming or discontinuous)
used. The proposed solver is compared with the open source direct solvers,
MUMPS and PasTiX. Further, the performance of the parallel multigrid solver is
analyzed up to 1080 processors. The solver shows a very good speedup up to 960
processors and the problem size has to be increased in order to maintain the
good speedup when the number of processors are increased further. As a result,
the parallel solver is able to handle large scale problems on massively
parallel supercomputers. The proposed parallel finite element algorithms and
multigrid solver are implemented in our in-house package ParMooN.


title: From the Skin-Depth Equation to the Inverse RFEC Sensor Model

abstract:
  In this paper, we tackle the direct and inverse problems for the Remote-Field
Eddy-Current (RFEC) technology. The direct problem is the sensor model, where
given the geometry the measurements are obtained. Conversely, the inverse
problem is where the geometry needs to be estimated given the field
measurements. These problems are particularly important in the field of
Non-Destructive Testing (NDT) because they allow assessing the quality of the
structure monitored. We solve the direct problem in a parametric fashion using
Least Absolute Shrinkage and Selection Operation (LASSO). The proposed inverse
model uses the parameters from the direct model to recover the thickness using
least squares producing the optimal solution given the direct model. This study
is restricted to the 2D axisymmetric scenario. Both, direct and inverse models,
are validated using a Finite Element Analysis (FEA) environment with realistic
pipe profiles.


title:
Spin-parity effect in violation of bell's inequalities for entangled
  states of parallel polarization

abstract:
  Bell inequalities (BIs) derived in terms of quantum probability statistics
are extended to general bipartite-entangled states of arbitrary spins with
parallel polarization. The original formula of Bell for the two-spin singlet is
slightly modified in the parallel configuration, while, the inequality for-
mulated by Clauser-Horne-Shimony-Holt remains not changed. The violation of BIs
indeed resulted from the quantum non-local correlation for spin-1=2 case.
However, the inequalities are always satisfied for the spin-1 entangled states
regardless of parallel or antiparallel polarizations of two spins. The spin
parity effect originally demonstrated with the antiparallel spin-polarizations
(Mod. Phys. Lett. B28, 145004) still exists for the parallel case. The quantum
non-locality does not lead to the violation for integer spins due to the
cancellation of non-local interference effects by the quantum
statistical-average. Again the violation of BIs seems a result of the
measurement induced nontrivial Berry-phase for half-integer spins.


title:
Equivalent Theories Redefine Hamiltonian Observables to Exhibit Change
  in General Relativity

abstract:
  Change and local spatial variation are missing in canonical General
Relativity's observables as usually defined, part of the problem of time.
Definitions can be tested using equivalent formulations, non-gauge and gauge,
because they must have equivalent observables and everything is observable in
the non-gauge formulation. Taking an observable from the non-gauge formulation
and finding the equivalent in the gauge formulation, one requires that the
equivalent be an observable, constraining definitions. For massive photons, the
de Broglie-Proca non-gauge formulation observable A_{\mu} is equivalent to the
Stueckelberg-Utiyama gauge formulation quantity A_{\mu}+\partial_{\mu} \phi.
Thus observables must have 0 Poisson bracket not with each first-class
constraint, but with the Rosenfeld-Anderson-Bergmann-Castellani gauge generator
G, a tuned sum of first-class constraints, in accord with the
Pons-Salisbury-Sundermeyer definition of observables.
  The definition for external gauge symmetries can be tested using massive
gravity, where one can install gauge freedom by parametrization with clock
fields X^A. The non-gauge observable g^{\mu\nu} has the gauge equivalent
X^A,_{\mu} g^{\mu\nu} X^B,_{\nu}. The Poisson bracket of X^A,_{\mu} g^{\mu\nu}
X^B,_{\nu} with G turns out to be not 0 but a Lie derivative. This non-zero
Poisson bracket refines and systematizes Kuchar's proposal to relax the 0
Poisson bracket condition with the Hamiltonian constraint. Thus observables
need covariance, not invariance, in relation to external gauge symmetries.
  The Lagrangian and Hamiltonian for massive gravity are those of General
Relativity + Lambda + 4 scalars, so the same definition of observables applies
to General Relativity. Local fields such as g_{\mu\nu} are observables. Thus
observables change. Requiring equivalent observables for equivalent theories
also recovers Hamiltonian-Lagrangian equivalence.


title: Quantum gravity on foliated spacetime - asymptotically safe and sound

abstract:
  Asymptotic Safety provides a mechanism for constructing a consistent and
predictive quantum theory of gravity valid on all length scales. Its key
ingredient is a non-Gaussian fixed point of the gravitational renormalization
group flow which controls the scaling of couplings and correlation functions at
high energy. In this work we use a functional renormalization group equation
adapted to the ADM-formalism for evaluating the gravitational renormalization
group flow on a cosmological Friedmann-Robertson-Walker background. Besides
possessing the UV-non-Gaussian fixed point characteristic for Asymptotic Safety
the setting exhibits a second non-Gaussian fixed point with a positive Newton's
constant and real critical exponents. The new fixed point alters the phase
diagram in such a way that all renormalization group trajectories connected to
classical general relativity are well-defined on all length scales. In
particular a positive cosmological constant is dynamically driven to zero in
the deep infrared. Moreover, the scaling dimensions associated with the
universality classes emerging within the causal setting exhibit qualitative
agreement with results found within the $\epsilon$-expansion around two
dimensions, Monte Carlo simulations based on Lattice Quantum Gravity, and the
discretized Wheeler-deWitt equation.


title:
The MOSDEF Survey: Metallicity Dependence of the PAH Emission at High
  Redshift and Implications for 24 micron-inferred IR Luminosities and Star
  Formation Rates at z~2

abstract:
  We present results on the variation of 7.7 micron Polycyclic Aromatic
Hydrocarbon (PAH) emission in galaxies spanning a wide range in metallicity at
z ~ 2. For this analysis, we use rest-frame optical spectra of 476 galaxies at
1.37 < z < 2.61 from the MOSFIRE Deep Evolution Field (MOSDEF) survey to infer
metallicities and ionization states. Spitzer/MIPS 24 micron and Herschel/PACS
100 and 160 micron observations are used to derive rest-frame 7.7 micron
luminosities (L(7.7)) and total IR luminosities (L(IR)), respectively. We find
significant trends between the ratio of L(7.7) to L(IR) (and to dust-corrected
SFR) and both metallicity and [OIII]/[OII] (O32) emission-line ratio. The
latter is an empirical proxy for the ionization parameter. These trends
indicate a paucity of PAH emission in low metallicity environments with harder
and more intense radiation fields. Additionally, L(7.7)/L(IR) is significantly
lower in the youngest quartile of our sample (ages of 500 Myr) compared to
older galaxies, which may be a result of the delayed production of PAHs by AGB
stars. The relative strength of L(7.7) to L(IR) is also lower by a factor of ~
2 for galaxies with masses $M_* < 10^{10}M_{\odot}$, compared to the more
massive ones. We demonstrate that commonly-used conversions of L(7.7) (or 24
micron flux density; f(24)) to L(IR) underestimate the IR luminosity by more
than a factor of 2 at $M_*$ ~ $10^{9.6-10.0} M_{\odot}$. We adopt a
mass-dependent conversion of L(7.7) to L(IR) with L(7.7)/L(IR)= 0.09 and 0.22
for $M_* < 10^{10}$ and $> 10^{10} M_{\odot}$, respectively. Based on the new
scaling, the SFR-$M_*$ relation has a shallower slope than previously derived.
Our results also suggest a higher IR luminosity density at z ~ 2 than
previously measured, corresponding to a ~ 30% increase in the SFR density.


title: Synchrotron masers and fast radio bursts

abstract:
  Fast Radio Bursts (FRBs), with a typical duration of 1 ms and 1 Jy flux
density at GHz frequencies, have brightness temperatures exceeding 1e33 K,
requiring a coherent emission process. This can be achieved by bunching
particles in volumes smaller than the typical wavelength, but this may be
challenging. Alternatively, we can have maser emission. Under certain
conditions, the synchrotron stimulated emission process can be more important
than true absorption, and a synchrotron maser can be created. This occurs when
the emitting electrons have a very narrow distribution of pitch angles and
energies. This process overcomes the difficulties of having extremely dense
bunches of particles and relaxes the light crossing time limits, since there is
no simple relation between the actual size of the source and the observed
variability timescale.


title:
An in-depth study of a neutron star accreting at low Eddington rate: On
  the possibility of a truncated disk and an outflow

abstract:
  Due to observational challenges our knowledge of low-level accretion flows
around neutron stars is limited. We present Nustar, Swift and Chandra
observations of the low-mass X-ray binary IGR J17062-6143, which has been
persistently accreting at ~0.1 per cent of the Eddington limit since 2006. Our
simultaneous Nustar/Swift observations show that the 0.5-79 keV spectrum can be
described by a combination of a power law with a photon index of Gamma~2, a
black body with a temperature of kT_bb~0.5 keV (presumably arising from the
neutron star surface), and disk reflection. Modeling the reflection spectrum
suggests that the inner accretion disk was located at R_in>100 GM/c2 (>225 km)
from the neutron star. The apparent truncation may be due to evaporation of the
inner disk into a radiatively-inefficient accretion flow, or due to the
pressure of the neutron star magnetic field. Our Chandra gratings data reveal
possible narrow emission lines near 1 keV that can be modeled as reflection or
collisionally-ionized gas, and possible low-energy absorption features that
could point to the presence of an outflow. We consider a scenario in which this
neutron star has been able to sustain its low accretion rate through magnetic
inhibition of the accretion flow, which gives some constraints on its magnetic
field strength and spin period. In this configuration, IGR J17062-6143 could
exhibit a strong radio jet as well as a (propeller-driven) wind-like outflow.


title:
The HI Probability Distribution Function and the Atomic-to-Molecular
  Transition in Molecular Clouds

abstract:
  We characterize the column density probability distributions functions (PDFs)
of the atomic hydrogen gas, HI, associated with seven Galactic molecular clouds
(MCs). We use 21 cm observations from the Leiden/Argentine/Bonn Galactic HI
Survey to derive column density maps and PDFs. We find that the peaks of the HI
PDFs occur at column densities ranging from ~1-2$\times 10^{21}$ cm$^2$
(equivalently, ~0.5-1 mag). The PDFs are uniformly narrow, with a mean
dispersion of $\sigma_{HI}\approx 10^{20}$ cm$^2$ (~0.1 mag). We also
investigate the HI-to-H$_2$ transition towards the cloud complexes and estimate
HI surface densities ranging from 7-16 $M_\odot$ pc$^{-2}$ at the transition.
We propose that the HI PDF is a fitting tool for identifying the HI-to-H$_2$
transition column in Galactic MCs.


title: Noise-induced subdiffusion in strongly localized quantum systems

abstract:
  We consider the dynamics of strongly localized systems subject to dephasing
noise with arbitrary correlation time. Although noise inevitably induces
delocalization, transport in the noise-induced delocalized phase is
subdiffusive in a parametrically large intermediate-time window. We argue for
this intermediate-time subdiffusive regime both analytically and using
numerical simulations on single-particle localized systems. Furthermore, we
show that normal diffusion is restored in the long-time limit, through
processes analogous to variable-range hopping. With numerical simulations based
on Lanczos exact diagonalization, we demonstrate that our qualitative
conclusions are also valid for interacting systems in the many-body localized
phase.

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


title:
Globular clusters in the far-ultraviolet: evidence for He-enriched
  second populations in extra-galactic globular clusters?

abstract:
  We investigate the integrated far-ultraviolet (FUV) emission from globular
clusters. We present new FUV photometry of M~87's clusters based on archival
HST WFPC2 F170W observations. We use these data to test the reliability of
published photometry based on HST STIS FUV-MAMA observations, which are now
known to suffer from significant red-leak. We generally confirm these previous
FUV detections, but suggest they may be somewhat fainter. We compare the FUV
emission from bright ($M_{V} < -9.0$) clusters in the Milky Way, M~31, M~81 and
M~87 to each other and to the predictions from stellar populations models.
Metal-rich globular clusters show a large spread in FUV-V, with some clusters
in M~31, M~81 and M~87 being much bluer than standard predictions. This
requires that some metal-rich clusters host a significant population of
blue/extreme horizontal branch (HB) stars. These hot HB stars are not
traditionally expected in metal-rich environments, but are a natural
consequence of multiple populations in clusters - since the enriched population
is observed to be He-enhanced and will therefore produce bluer HB stars, even
at high metallicity. We conclude that the observed FUV emission from metal-rich
clusters in M~31, M~81 and M~87 provides evidence that He-enhanced second
populations, similar to those observed directly in the Milky Way, may be a
ubiquitous feature of globular clusters in the local universe. Future HST FUV
photometry is required to both confirm our interpretation of these archival
data and provide constraints on He-enriched second populations of stars in
extra-galactic globular clusters.


title: The Discovery of a Low-Luminosity SPIRAL DRAGN

abstract:
  Standard galaxy formation models predict that large-scale double-lobed radio
sources, known as DRAGNs, will always be hosted by elliptical galaxies. In
spite of this, in recent years a small number of spiral galaxies have also been
found to host such sources. These so-called spiral DRAGNs are still extremely
rare, with only $\sim 5$ cases being widely accepted. Here we report on the
serendipitous discovery of a new spiral DRAGN in data from the Giant Metrewave
Radio Telescope (GMRT) at 322 MHz. The host galaxy, MCG+07-47-10, is a face-on
late-type Sbc galaxy with distinctive spiral arms and prominent bulge
suggesting a high black hole mass. Using WISE infra-red and GALEX UV data we
show that this galaxy has a star formation rate of 0.16-0.75
M$_{\odot}$yr$^{-1}$, and that the radio luminosity is dominated by
star-formation. We demonstrate that this spiral DRAGN has similar environmental
properties to others of this class, but has a comparatively low radio
luminosity of $L_{\rm 1.4GHz}$ = 1.12$\times$10$^{22}$ W Hz$^{-1}$, two orders
of magnitude smaller than other known spiral DRAGNs. We suggest that this may
indicate the existence of a previously unknown low-luminosity population of
spiral DRAGNS.


title:
Late decaying 2-component dark matter scenario as an explanation of the
  AMS-02 positron excess

abstract:
  The long standing anomaly in the positron flux as measured by the PAMELA and
AMS-02 experiments could potentially be explained by dark matter (DM)
annihilations. This scenario typically requires a large "boost factor" to be
consistent with a thermal relic dark matter candidate produced via freeze-out.
However, such an explanation is disfavored by constraints from CMB observations
on energy deposition during the epoch of recombination. We discuss a scenario
called late-decaying two-component dark matter (LD2DM), where the entire DM
consists of two semi-degenerate species. Within this framework, the heavier
species is produced as a thermal relic in the early universe and decays to the
lighter species over cosmological timescales. Consequently, the lighter species
becomes the DM which populates the universe today. We show that annihilation of
the lighter DM species with an enhanced cross-section, produced via such a
non-thermal mechanism, can explain the observed AMS-02 positron flux while
avoiding CMB constraints. The observed DM relic density can be correctly
reproduced as well with simple s-wave annihilation cross-sections. We
demonstrate that the scenario is safe from CMB constraints on late-time energy
depositions during the cosmic "dark ages". Interestingly, structure formation
constraints force us to consider small mass splittings between the two dark
matter species. We explore possible cosmological and particle physics
signatures in a toy model that realizes this scenario.


title:
A free-form lensing model of A370 revealing stellar mass dominated BCGs,
  in Hubble Frontier Fields images

abstract:
  We derive a free-form mass distribution for the unrelaxed cluster A370
(z=0.375), using the latest Hubble Frontier Fields images and GLASS
spectroscopy. Starting from a reliable set of 10 multiply lensed systems we
produce a free-form lens model that identifies ~ 80 multiple-images. Good
consistency is found between models using independent subsamples of these
lensed systems, with detailed agreement for the well resolved arcs. The mass
distribution has two very similar concentrations centred on the two prominent
Brightest Cluster Galaxies (or BCGs), with mass profiles that are accurately
constrained by a uniquely useful system of long radially lensed images centred
on both BCGs. We show that the lensing mass profiles of these BCGs are mainly
accounted for by their stellar mass profiles, with a modest contribution from
dark matter within r<100 kpc of each BCG. This conclusion may favour a cooled
cluster gas origin for BCGs, rather than via mergers of normal galaxies for
which dark matter should dominate over stars. Growth via merging between BCGs
is, however, consistent with this finding, so that stars still dominate over
dark matter .


title:
Orbits of Massive Satellite Galaxies: I. A Close Look at the Large
  Magellanic Cloud and a New Orbital History for M33

abstract:
  The Milky Way (MW) and M31 both harbor massive satellite galaxies, the Large
Magellanic Cloud (LMC) and M33, which may comprise up to 10 per cent of their
host's total mass. Massive satellites can change the orbital barycentre of the
host-satellite system by tens of kiloparsecs and are cosmologically expected to
harbor dwarf satellite galaxies of their own. Assessing the impact of these
effects depends crucially on the orbital histories of the LMC and M33. Here, we
revisit the dynamics of the MW-LMC system and present the first detailed
analysis of the M31-M33 system utilizing high precision proper motions and
statistics from the dark matter-only Illustris cosmological simulation. With
the latest Hubble Space Telescope proper motion measurements of M31, we
reliably constrain M33's interaction history with its host. In particular, like
the LMC, M33 is either on its first passage (t_{inf} < 2 Gyr ago) or if M31 is
massive (>=2x10^12 Msun), it is on a long period orbit of about 6 Gyr.
Cosmological analogs of the LMC and M33 identified in Illustris support this
picture and provide further insight about their host masses. We conclude that,
cosmologically, massive satellites like the LMC and M33 are likely completing
their first orbits about their hosts. We also find that the orbital energies of
such analogs prefer a MW halo mass ~1.5x10^12 Msun and an M31 halo mass
>=1.5x10^12 Msun. Despite conventional wisdom, we conclude it is highly
improbable that M33 made a close (< 100 kpc) approach to M31 recently (
t_{peri} < 3 Gyr ago). Such orbits are rare (< 1 per cent) within the 4$\sigma$
error space allowed by observations. This conclusion cannot be explained by
perturbative effects through four body encounters between the MW, M31, M33, and
the LMC. This surprising result implies that we must search for a new
explanation for M33's strongly warped gas and stellar discs.


title:
High Resolution Observations of Molecular Lines in Arp 220: Kinematics,
  Morphology, and Limits on the Applicability of the Ammonia Thermometer

abstract:
  We observe Arp 220, the nearest Ultra-Luminous Infrared Galaxy (ULIRG), over
4 GHz in the K and Ka bands. We provide constraints for the
kinematics,morphology, and identify molecular species on scales resolving both
nuclei (0.6" or 230 pc). We detect multiple molecular species, including
hydroxyl in both cores. We tentatively detect H2O at 21.84 GHz in both nuclei,
indicating the likely presence of maser emission. The observed frequency range
also contains metastable ammonia transitions from (J,K) = (1,1) to (5,5), as
well as the (9,9) inversion line, which, together are a well-known thermometer
of dense molecular gas. Furthermore, the non-metastable (4,2) and (10,9) and
possibly the (3,1) lines are also detected. We apply a standard temperature
analysis to Arp 220. However, the analysis is complicated in that standard LTE
assumptions do not hold. There are indications that a substantial fraction of
ammonia could be in the non-metastable transitions as opposed to only the
metastable ones. Thus, the non-metastable transitions could be essential to
constraining the temperature. We compare all of these data to ALMA observations
of this source, confirming the outflow previously observed by other tracers in
both nuclei.


title:
WIMP capture by the Sun in the effective theory of dark matter
  self-interactions

abstract:
  We study the capture of WIMP dark matter by the Sun in the non-relativistic
effective theory of dark matter self-interactions. The aim is to assess the
impact of self-interactions on the expected neutrino flux from the annihilation
of WIMPs trapped in the Sun in a model independent manner. We consider all
non-relativistic Galilean invariant self-interaction operators that can arise
from the exchange of a heavy particle of spin less than or equal to 1 for WIMPs
of spin equal to 0, 1/2 and 1. We show that for interaction operators depending
at most linearly on the momentum transfer, the WIMP-induced neutrino flux can
be enhanced by several orders of magnitude compared to the same flux in absence
of self-interactions. This is true even for standard values of the thermally
averaged annihilation cross-section. This conclusion impacts the analysis of
present and future observations performed at neutrino telescopes.


title:
A Stringent Limit on the Mass Production Rate of $r$-Process Elements in
  the Milky Way

abstract:
  We analyze data from several studies of metal-poor stars in the Milky Way,
focusing on both strong (Eu) and weak (Sr) $r$-process elements. Because these
elements were injected in an explosion, we calculate the mass swept up when the
blast wave first becomes radiative, yielding a lower limit for the dilution of
such elements and hence a lower limit on the ejecta mass which is incorporated
into the next generation of stars. Our study demonstrates that in order to
explain the largest enhancements in [Eu/Fe] observed in stars at low [Fe/H]
metallicities, individual $r$-process production events must synthesize a
minimum of $10^{-3.5} M_{\odot}$ of $r$-process material. We also show that if
the site of Mg production is the same as that of Eu, individual injection
events must synthesize up to $ \sim 10^{-3} M_{\odot}$ of $r$-process material.
On the other hand, demanding that Sr traces Mg production results in
$r$-process masses per event of $\sim 10^{-5} M_{\odot}$. This suggests that
the astrophysical sites responsible for the genesis of the strong $r$-process
elements need to operate at a drastically reduced rate when compared to
core-collapse supernovae, while the synthesis of the weak $r$-process material
is consistent with a supernova production site.


title:
Updates to the p+p and A+A chemical freeze-out lines from the new
  experimental data

abstract:
  We show that the new data on mean multiplicities measured in p+p and A+A
collisions together with the updated list of resonances lead to the significant
changes of the obtained freeze-out lines. The new A+A line gives much smaller
temperatures at high collision energies and agrees with the values obtained at
the LHC. The newly obtained p+p line is much closer to the A+A line than
previously expected, and even touches it in the region where the $K^+/\pi^+$
horn appears in the data. It indicates that the temperatures that will be
obtained in the beam energy and system size scan by the NA61/SHINE
Collaboration might be very close. However, our analysis shows that the
chemical potentials could be very different for the same energies in A+A and
p+p. It adds more puzzles to the set of surprising coincidences at the energies
close to the possible onset of deconfinement.


title:
The Properties of Short gamma-ray burst Jets Triggered by neutron star
  mergers

abstract:
  The most popular model for short gamma-ray bursts (sGRBs) involves the
coalescence of binary neutron stars. Because the progenitor is actually hidden
from view, we must consider under which circumstances such merging systems are
capable of producing a successful sGRB. Soon after coalescence, winds are
launched from the merger remnant. In this paper, we use realistic wind profiles
derived from global merger simulations in order to investigate the interaction
of sGRB jets with these winds using numerical simulations. We analyze the
conditions for which these axisymmetric winds permit relativistic jets to
breakout and produce a sGRB. We find that jets with luminosities comparable to
those observed in sGRBs are only successful when their half-opening angles are
below ~20{\deg}. This jet collimation mechanism leads to a simple physical
interpretation of the luminosities and opening angles inferred for sGRBs. If
wide, low luminosity jets are observed, they might be indicative of a different
progenitor avenue such as the merger of a neutron star with a black hole. We
also use the observed durations of sGRB to place constraints on the lifetime of
the wind phase, which is determined by the time it takes the jet to breakout.
In all cases we find that the derived limits argue against completely stable
remnants for binary neutron star mergers that produce sGRBs.


title:
Optical Spectroscopic Observations of Gamma-ray Blazar Candidates. V.
  TNG, KPNO, and OAN Observations of Blazar Candidates of Uncertain Type in the
  Northern Hemisphere

abstract:
  The extragalactic $\gamma$-ray sky is dominated by emission from blazars, a
peculiar class of active galactic nuclei (AGNs). Many of the $\gamma$-ray
sources included in Fermi -Large Area Telescope Third Source catalog (3FGL) are
classified as a blazar candidate of uncertain type (BCU) because there is no
optical spectra available in the literature to confirm their nature. In 2013 we
started a spectroscopic campaign to look for the optical counterparts of the
BCUs and of the Unidentified $\gamma$-ray Sources. The main goal of our
investigation is to confirm the blazar nature of these sources having peculiar
properties as compact radio emission and/or selected on the basis of their
infrared (IR) colors. Whenever possible we also determine their redshifts. Here
we present the results of the observations carried out in the Northern
hemisphere in 2013 and 2014 at Telescopio Nazionale Galilleo (TNG), Kitt Peak
National Observatory (KPNO) and Observatorio Astron\'omico Nacional (OAN) in
San Pedro M\'artir. In this paper we describe the optical spectra of 25
sources. We confirmed that all the 15 BCUs observed in our campaign and
included in our sample are blazars and we estimated the redshift for 3 of them.
In addition, we present the spectra for 3 sources classified as BL Lacs in the
literature but with no optical spectra available to date. We found that one of
them is a quasar (QSO) at a redshift $z$ = 0.208 and the other 2 are BL Lacs.
Moreover, we also present 7 new spectra for known blazars listed in the
Roma-BZCAT having an uncertain redshift or being classified as BL Lac
candidates. We found that one of them, 5BZB J0724+2621 is a `changing look'
blazar. According to the spectrum available in the literature it was classified
as a BL Lac but in our observation we clearly detected a broad emission line
that lead to classify this source as a QSO at $z$=1.17.


title: Visible Light-Based Human Visual System Conceptual Model

abstract:
  There exists a widely accepted set of assertions in the digital image and
video coding literature, which are as follows: the Human Visual System (HVS) is
more sensitive to luminance (often confused with brightness) than photon
energies (often confused with chromaticity and chrominance). Passages similar
to the following occur with high frequency in the peer reviewed literature and
academic text books: "the HVS is much more sensitive to brightness than colour"
and/or "the HVS is much more sensitive to luma than chroma". In this discussion
paper, a Visible Light-Based Human Visual System (VL-HVS) conceptual model is
discussed. The objectives of VL-HVS are as follows: 1. To provide a deeper
theoretical reflection of the fundamental relationship between visible light,
the manifestation of colour perception derived from visible light and the
physiology of the perception of colour. That is, in terms of the physics of
visible light, photobiology and the human subjective interpretation of visible
light, it is appropriate to provide comprehensive background information in
relation to the natural interactions between visible light, the retinal
photoreceptors and the subsequent cortical processing of such. 2. To provide a
more wholesome account with respect to colour information in digital image and
video processing applications. 3. To recontextualise colour data in the RGB and
YCbCr colour spaces, such that novel techniques in digital image and video
processing, including quantisation and artifact reduction techniques, may be
developed based on both luma and chroma information (not luma data only).


title: Higgs-Stoponium Mixing Near the Stop-Antistop Threshold

abstract:
  Supersymmetric extensions of the standard model contain additional heavy
neutral Higgs bosons that are coupled to heavy scalar top quarks (stops). This
system exhibits interesting field theoretic phenomena when the Higgs mass is
close to the stop-antistop production threshold. Existing work in the
literature has examined the digluon-to-diphoton cross section near threshold
and has focused on enhancements in the cross section that might arise either
from the perturbative contributions to the Higgs-to-digluon and
Higgs-to-diphoton form factors or from mixing of the Higgs boson with stoponium
states. Near threshold, enhancements in the relevant amplitudes that go as
inverse powers of the stop-antistop relative velocity require resummations of
perturbation theory and/or nonperturbative treatments. We present a complete
formulation of threshold effects at leading order in the stop-antistop relative
velocity in terms of nonrelativistic effective field theory. We give detailed
numerical calculations for the case in which the stop-antistop Green's function
is modeled with a Coulomb-Schr\"odinger Green's function. We find several
general effects that do not appear in a purely perturbative treatment.
Higgs-stop-antistop mixing effects displace physical masses from the threshold
region, thereby rendering the perturbative threshold enhancements inoperative.
In the case of large Higgs-stop-antistop couplings, the displacement of a
physical state above threshold substantially increases its width, owing to its
decay width to a stop-antistop pair, and greatly reduces its contribution to
the cross section.


title:
Incidence of WISE-Selected Obscured AGNs in Major Mergers and
  Interactions from the SDSS

abstract:
  We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital
Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic
nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z <= 0.08)
catalog of visually-selected major mergers and galaxy-galaxy interactions from
the SDSS, with stellar masses above 2x10^10 Msun, we find that major mergers
(interactions) are 5-17 (3-5) times more likely to have red [3.4]-[4.6] colors
associated with dust-obscured or `dusty' AGNs, compared to non-merging galaxies
with similar masses. Using published fiber spectral diagnostics, we map the
[3.4]-[4.6] versus [4.6]-[12] colors of different emission-line galaxies and
find one-quarter of Seyferts have colors indicative of a dusty AGN. We find
that AGNs are five times more likely to be obscured when hosted by a merging
galaxy, half of AGNs hosted by a merger are dusty, and we find no enhanced
frequency of optical AGNs in merging over non-merging galaxies. We conclude
that undetected AGNs missed at shorter wavelengths are at the heart of the
ongoing AGN-merger connection debate. The vast majority of mergers hosting
dusty AGNs are star-forming and located at the centers of Mhalo<10^13 Msun
groups. Assuming plausibly short duration dusty-AGN phases, we speculate that a
large fraction of gas-rich mergers experience a brief obscured AGN phase, in
agreement with the strong connection between central star formation and black
hole growth seen in merger simulations.


title:
Electroweak Higgs boson production in the standard model effective field
  theory beyond leading order in QCD

abstract:
  We study the impact of dimension-six operators of the standard model
effective field theory relevant for vector-boson fusion and associated Higgs
boson production at the LHC. We present predictions at the next-to-leading
order accuracy in QCD that include matching to parton showers and that rely on
fully automated simulations. We show the importance of the subsequent reduction
of the theoretical uncertainties in improving the possible discrimination
between effective field theory and standard model results, and we demonstrate
that the range of the Wilson coefficient values allowed by a global fit to LEP
and LHC Run~I data can be further constrained by LHC Run~II future results.


title: Spin Transport through the metallic antiferromagnet FeMn

abstract:
  We investigate spin transport through metallic antiferromagnets using
measurements based on spin pumping combined with inverse spin Hall effects in
Ni80Fe20/FeMn/W trilayers. The relatively large magnitude and opposite sign of
spin Hall effects in W compared to FeMn enable an unambiguous detection of spin
currents transmitted through the entire FeMn layer thickness. Using this
approach we can detect two distinctively different spin transport regimes,
which we associate with electronic and magnonic spin currents respectively. The
latter can extend to relatively large distances (up to 9 nm) and is enhanced
when the antiferromagnetic ordering temperature is close to the measurement
temperature.


title:
Augmenting Collider Searches and Enhancing Discovery Potentials through
  Stochastic Jet Grooming

abstract:
  The jet Trimming procedure has been demonstrated to greatly improve event
reconstruction in hadron collisions, by mitigating contamination due initial
state radiation, multiple interactions, and event pileup. Meanwhile, Qjets -- a
nondeterministic approach to tree-based jet substructure has been shown to be a
powerful technique in decreasing random statistical fluctuations, yielding
significant effective luminosity improvements. This manifests through an
improvement in the significance $S/\delta B$, relative to conventional methods.
Qjets also provide novel observables in many cases, like mass-volatility, that
could be used to further discriminate between signal and background events. The
statistical robustness and volatility observables, for tagging, are obtained
simultaneously. We explore here a combination of the two techniques, and
demonstrate that significant enhancements in discovery potentials may be
obtained in non-trivial ways. We will illustrate this by considering a diboson
resonance analysis as a case study -- enabling us to interpolate between
scenarios where the gains are purely due to statistical robustness and
scenarios where the gains are also reinforced by volatility variable
discriminants. The former, for instance, is applicable to digluon/diquark
resonances, while the latter will be of relevance to di-$W^\pm$/di-$Z^0$
resonances, where the boosted vector bosons are decaying hadronically and have
an intrinsic mass scale attached to them. We argue that one can enhance signal
significance and discovery potentials markedly through stochastic grooming, and
help augment studies at the Large Hadron Collider and future hadron colliders.


title:
On Large-Batch Training for Deep Learning: Generalization Gap and Sharp
  Minima

abstract:
  The stochastic gradient descent (SGD) method and its variants are algorithms
of choice for many Deep Learning tasks. These methods operate in a small-batch
regime wherein a fraction of the training data, say $32$-$512$ data points, is
sampled to compute an approximation to the gradient. It has been observed in
practice that when using a larger batch there is a degradation in the quality
of the model, as measured by its ability to generalize. We investigate the
cause for this generalization drop in the large-batch regime and present
numerical evidence that supports the view that large-batch methods tend to
converge to sharp minimizers of the training and testing functions - and as is
well known, sharp minima lead to poorer generalization. In contrast,
small-batch methods consistently converge to flat minimizers, and our
experiments support a commonly held view that this is due to the inherent noise
in the gradient estimation. We discuss several strategies to attempt to help
large-batch methods eliminate this generalization gap.


title: From fifty years ago, the birth of modern liquid-state science

abstract:
  The story told in this autobiographical perspective begins fifty years ago at
the 1967 Gordon Research Conference on the Physics and Chemistry of Liquids. It
traces developments in liquid-state science from that time, including
contributions from the author, and especially in the study of liquid water. It
emphasizes the importance of fluctuations, and the challenges of
far-from-equilibrium phenomena.


title:
Photon initiated single top quark production via flavor-changing neutral
  currents at the LHC

abstract:
  Single top quark production is a powerful process to search for new physics
signs. In this work we propose and investigate a search for top quark flavor
changing neutral currents (FCNC) via a photon using direct single top quark
production events in proton-proton collisions at the LHC at CERN. We show that
the direct single top quark final state can provide constraints on the
strengths of tq$\gamma$ (top-quark-$\gamma$) and tqg (top-quark-gluon) FCNC
couplings simultaneously. Results of a search for direct single top quark
production at the LHC at a center-of-mass energy of 8 TeV performed by the
ATLAS collaboration are used to set first experimental limits on the anomalous
FCNC top decay branching fractions ${\cal B}$(t$\rightarrow$ u$\gamma$) $<$
0.05% and ${\cal B}$(t$\rightarrow$ c$\gamma$) $<$ 0.14% via direct single top
quark production. Finally, the sensitivity of the proposed channel for probing
the tq$\gamma$ couplings at 13 TeV is presented.


title:
Semilocal exchange hole with an application to range-separation density
  functional

abstract:
  Exchange-correlation hole is a central concept in density functional theory.
It not only provides justification for an exchange-correlation energy
functional, but also serves as a local ingredient in nonlocal range-separation
density functional. However, due to the nonlocal nature, modelig the
conventional exact exchange hole presents a great challenge to density
functional theory. In this work, we propose a semilocal exchange hole
underlying the Tao-Perdew-Staroverov-Scuseria (TPSS) meta-GGA functional. The
present model is distinct from previous models at small separation between an
electron and the hole around the electron. It is also different in the way it
interpolates between the rapidly varying iso-orbital density and the slowly
varying density, which is determined by the wave vector analysis based on the
exactly solvable infinite barrier model for jellium surface. Our numerical
tests show that the exchange hole generated from this model mimics the
conventional exact exchange hole quite well for atoms. Finally, as a simple
application, we apply the hole model to construct a TPSS-based range-separation
functional. Our tests show that this TPSS-based range-separation functional can
substantially improve TPSS band gaps and barrier heights, without losing much
accuracy of molecular atomization energies.


title: Dictionary learning of sound speed profiles

abstract:
  To provide constraints on their inversion, ocean sound speed profiles (SSPs)
often are modeled using empirical orthogonal functions (EOFs). However, this
regularization, which uses the leading order EOFs with a minimum-energy
constraint on their coefficients, often yields low resolution SSP estimates. In
this paper, it is shown that dictionary learning, a form of unsupervised
machine learning, can improve SSP resolution by generating a dictionary of
shape functions for sparse processing (e.g. compressive sensing) that optimally
compress SSPs; both minimizing the reconstruction error and the number of
coefficients. These learned dictionaries (LDs) are not constrained to be
orthogonal and thus, fit the given signals such that each signal example is
approximated using few LD entries. Here, LDs describing SSP observations from
the HF-97 experiment and the South China Sea are generated using the K-SVD
algorithm. These LDs better explain SSP variability and require fewer
coefficients than EOFs, describing much of the variability with one
coefficient. Thus, LDs improve the resolution of SSP estimates with negligible
computational burden.

categories: physics.ao-ph cs.IT math.IT physics.data-an physics.geo-ph


title:
A Measurement of Radius Inflation in the Pleiades and its Relation to
  Rotation and Lithium Depletion

abstract:
  Precise measurements of eclipsing binary parameters and statistical studies
of young clusters have suggested that some magnetically active low-mass dwarfs
possess radii inflated by $\sim$5-15% relative to theoretical expectations. If
true, this effect should be pronounced in young open clusters, due to the rapid
rotation and strong magnetic activity of their most extreme members. We explore
this possibility by determining empirical radii for 83 members of the nearby
Pleiades open cluster, using spectral energy distribution fitting to establish
$\mathcal{F}_{bol}$ with a typical accuracy of $\approx$3\% together with color
and spectro-photometric indices to determine $T_{\rm eff}$. We find several
Pleiades members with radii inflated above radius-$T_{\rm eff}$ models from
state-of-the-art calculations, and apparent dispersions in radii for the
K-dwarfs of the cluster. Moreover, we demonstrate that this putative radius
inflation correlates strongly with rotation rate, consistent with inflation of
young stars by magnetic activity and/or starspots. We argue that this signal is
not a consequence of starspot-induced color anomalies, binarity, or depth
effects in the cluster, employing Gaia DR1 distances as a check. Finally, we
consider the lithium abundances of these stars, demonstrating a triple
correlation between rotation rate, radius inflation, and enhanced lithium
abundance. Our result---already significant to $\sim$99.99%
confidence---provides strong support for a magnetic origin of the inflated
radii and lithium dispersion observed in young, low-mass stars.


title: Noncommutative resolutions using syzygies

abstract:
  Given a noether algebra with a noncommutative resolution, a general
construction of new noncommutative resolutions is given. As an application, it
is proved that any finite length module over a regular local or polynomial ring
gives rise, via suitable syzygies, to a noncommutative resolution.


title:
Analyzing Ozone Concentration by Bayesian Spatio-temporal Quantile
  Regression

abstract:
  Ground level Ozone is one of the six common air-pollutants on which the EPA
has set national air quality standards. In order to capture the spatio-temporal
trend of 1-hour and 8-hour average ozone concentration in the US, we develop a
method for spatio-temporal simultaneous quantile regression. Unlike existing
procedures, in the proposed method, smoothing across the sites is incorporated
within modeling assumptions thus allowing borrowing of information across
locations, an essential step when the number of samples in each location is
low. The quantile function has been assumed to be linear in time and smooth
over space and at any given site is given by a convex combination of two
monotone increasing functions $\xi_1$ and $\xi_2$ not depending on time. A
B-spline basis expansion with increasing coefficients varying smoothly over the
space is used to put a prior and a Bayesian analysis is performed. We analyze
the average daily 1-hour maximum and 8-hour maximum ozone concentration level
data of US and California during 2006-2015 using the proposed method. It is
noted that in the last ten years, there is an overall decreasing trend in both
1-hour maximum and 8-hour maximum ozone concentration level over the most parts
of the US. In California, an overall a decreasing trend of 1-hour maximum ozone
level is observed while no particular overall trend has been observed in the
case of 8-hour maximum ozone level.


title:
Energy-efficient Traffic Allocation in SDN-based Backhaul Networks:
  Theory and Implementation

abstract:
  5G networks are expected to be highly energy efficient, with a 10 times lower
consumption than today's systems. An effective way to achieve such a goal is to
act on the backhaul network by controlling the nodes operational state and the
allocation of traffic flows. To this end, in this paper we formulate
energy-efficient flow routing on the backhaul network as an optimization
problem. In light of its complexity, which impairs the solution in large-scale
scenarios, we then propose a heuristic approach. Our scheme, named EMMA, aims
to both turn off idle nodes and concentrate traffic on the smallest possible
set of links, which in its turn increases the number of idle nodes. We
implement EMMA on top of ONOS and derive experimental results by emulating the
network through Mininet. Our results show that EMMA provides excellent energy
saving performance, which closely approaches the optimum. In larger network
scenarios, the gain in energy consumption that EMMA provides with respect to
the simple benchmark where all nodes are active, is extremely high, reaching
almost 1 under medium-low traffic load.


title: The awakening of the gamma-ray narrow-Line Seyfert 1 galaxy PKS 1502+036

abstract:
  After a long low-activity period, a gamma-ray flare from the narrow-line
Seyfert 1 PKS 1502+036 (z=0.4089) was detected by the Large Area Telescope
(LAT) on board Fermi in 2015. On 2015 December 20 the source reached a daily
peak flux, in the 0.1-300 GeV band, of (93 $\pm$ 19) $\times$10$^{-8}$ ph
cm$^{-2}$ s$^{-1}$, attaining a flux of (237 $\pm$ 71) $\times$10$^{-8}$ ph
cm$^{-2}$ s$^{-1}$ on 3-hr time-scales, which corresponds to an isotropic
luminosity of (7.3 $\pm$ 2.1) $\times$10$^{47}$ erg/s. The gamma-ray flare was
not accompanied by significant spectral changes. We report on multi-wavelength
radio-to-gamma-ray observations of PKS 1502+036 during 2008 August-2016 March
by Fermi-LAT, Swift, XMM-Newton, Catalina Real-Time Transient Survey, and the
Owens Valley Radio Observatory (OVRO). An increase in activity was observed on
2015 December 22 by Swift in optical, UV, and X-rays. The OVRO 15 GHz light
curve reached the highest flux density observed from this source on 2016
January 12, indicating a delay of about three weeks between the gamma-ray and
15 GHz emission peaks. This suggests that the gamma-ray emitting region is
located beyond the broad line region. We compared the spectral energy
distribution (SED) of an average activity state with that of the flaring state.
The two SED, with the high-energy bump modelled as an external Compton
component with seed photons from a dust torus, could be fitted by changing the
electron distribution parameters as well as the magnetic field. The fit of the
disc emission during the average state constrains the black hole mass to values
lower than 10$^8$ solar masses. The SED, high-energy emission mechanisms, and
gamma-ray properties of the source resemble those of a flat spectrum radio
quasar.


title: A Tutorial about Random Neural Networks in Supervised Learning

abstract:
  Random Neural Networks (RNNs) are a class of Neural Networks (NNs) that can
also be seen as a specific type of queuing network. They have been successfully
used in several domains during the last 25 years, as queuing networks to
analyze the performance of resource sharing in many engineering areas, as
learning tools and in combinatorial optimization, where they are seen as neural
systems, and also as models of neurological aspects of living beings. In this
article we focus on their learning capabilities, and more specifically, we
present a practical guide for using the RNN to solve supervised learning
problems. We give a general description of these models using almost
indistinctly the terminology of Queuing Theory and the neural one. We present
the standard learning procedures used by RNNs, adapted from similar
well-established improvements in the standard NN field. We describe in
particular a set of learning algorithms covering techniques based on the use of
first order and, then, of second order derivatives. We also discuss some issues
related to these objects and present new perspectives about their use in
supervised learning problems. The tutorial describes their most relevant
applications, and also provides a large bibliography.


title:
Enhanced plasmonic coloring of silver and formation of large
  laser-induced periodic surface structures using multi-burst picosecond pulses

abstract:
  We report on the creation of angle-independent colors on silver using closely
time-spaced laser bursts. The use of burst mode, compared to traditional
non-burst is shown to increase the Chroma (color saturation) by ~50% and to
broaden the lightness range by up to ~60%. Scanning electron microscope
analysis of the surfaces created using burst mode, reveal the creation of 3
distinct sets of laser induced periodic surface structures (LIPSS): low spatial
frequency LIPSS (LSFL), high spatial frequency LIPSS (HSFL) and large
laser-induced periodic surface structures (LLIPSS) that are 10 times the laser
wavelength and parallel to the laser polarization. Nanoparticles are
responsible for each plasmonic color and their distributions are observed to be
similar for both burst and non-burst modes, indicating that the underlying
structures (i.e. LIPSSs) are responsible for the increased Chroma and
Lightness. Two-temperature model simulations of silver irradiated by laser
bursts show significant increase in the electron-phonon coupling coefficient
which is crucial for the creation of well-defined ripple structures. Finite
difference time domain (FDTD) simulations of the colored surfaces show the
increase in Chroma to be attributable to the HSFL arising in burst mode.


title:
Ballistic edge states in Bismuth nanowires revealed by SQUID
  interferometry

abstract:
  Spin-orbit interactions are known to have drastic effects on the band
structure of heavy-element-based materials. Celebrated examples are the
recently identified 3D and 2D topological insulators. In those systems
transport takes place at surfaces or along edges, and spin-momentum locking
provides protection against (non-magnetic) impurity scattering, favoring
spin-polarized ballistic transport. We have used the measurement of the current
phase relation of a micrometer-long single crystal bismuth nanowire connected
to superconducting electrodes, to demonstrate that transport occurs
ballistically along two edges of this high-spin-orbit material. In addition, we
show that a magnetic field can induce to 0-pi transitions and phi0-junction
behavior, thanks to the extraordinarily high g-factor and spin orbit coupling
in this system, providing a way to manipulate the phase of the
supercurrent-carrying edge states.


title:
Predicting Shot Making in Basketball Learnt from Adversarial Multiagent
  Trajectories

abstract:
  In this paper, we predict the likelihood of a player making a shot in
basketball from multiagent trajectories. Previous approaches to similar
problems center on hand-crafting features to capture domain specific knowledge.
Although intuitive, recent work in deep learning has shown this approach is
prone to missing important predictive features. To circumvent this issue, we
present a convolutional neural network (CNN) approach where we initially
represent the multiagent behavior as an image. To encode the adversarial nature
of basketball, we use a multi-channel image which we then feed into a CNN.
Additionally, to capture the temporal aspect of the trajectories we "fade" the
player trajectories. We find that this approach is superior to a traditional
FFN model. By using gradient ascent to create images using an already trained
CNN, we discover what features the CNN filters learn. Last, we find that a
combined CNN+FFN is the best performing network with an error rate of 39%.


title:
Plasmonic structure integrated single-photon detectors optimized to
  maximize polarization contrast

abstract:
  Numerical optimization was performed via COMSOL Multiphysics to maximize the
polarization contrast of superconducting nanowire single photon detectors
(SNSPDs). SNSPDs were integrated with four different types of one-dimensional
periodic plasmonic structures capable of mediating p-polarized photon
selectivity to the niobium-nitride superconducting nanowire pattern.
Optimization with two different criteria regarding the maximal tilting resulted
in wavelength-scaled periodic integrated structures, which have different
geometrical parameters, and exhibit different polar angle dependent optical
response and dispersion characteristics, as well as accompanying near-field
phenomena at the extrema. Polarization contrast of 6.37*10^2 and 3.28*10^2 -
6.86*10^11 and 1.42*10^11 - 1.81*10^13 and 7.87*10^12 - 1.90*10^3 and 1.15*10^5
can be achieved in nanocavity-, nanocavity-deflector-,
nanocavity-double-deflector-, nanocavity-trench-array-integrated P-SNSPDs
optimized with 85 degree and 80 degree criterion regarding the maximal tilting.


title:
Kinetic turbulence in relativistic plasma: from thermal bath to
  non-thermal continuum

abstract:
  We present results from particle-in-cell simulations of driven turbulence in
magnetized, collisionless, and relativistic pair plasma. We find that
fluctuations are consistent with the classical $k_\perp^{-5/3}$ magnetic energy
spectrum at fluid scales and a steeper $k_\perp^{-4}$ spectrum at sub-Larmor
scales, where $k_\perp$ is the wavevector perpendicular to the mean field. We
demonstrate the development of a non-thermal, power-law particle energy
distribution, $f(E) \sim E^{-\alpha}$, with index $\alpha$ that decreases with
increasing magnetization and increases with increasing system size (relative to
the characteristic Larmor radius). Our simulations indicate that turbulence can
be a viable source of energetic particles in high-energy astrophysical systems,
such as pulsar wind nebulae, if scalings asymptotically become insensitive to
the system size.


title: Construction of Benford Random Variables: Generators and Seed Functions

abstract:
  In this paper I describe two general methods of constructing a probability
density function (pdf) of a Benford random variable, and show that the pdf of
every Benford random variable may be constructed by these methods. These
constructions are helpful in exploring the nature of Benford random variables,
and may be used to investigate some issues of base dependency of Benford random
variables.


title: Generating resonating valence bond states through Dicke subradiance

abstract:
  Dicke's original thought experiment with two spins coupled to a photon mode
has recently been experimentally realized. We propose extending this experiment
to N spins and show that it naturally gives rise to highly entangled states. In
particular, it gives rise to dark states which have resonating valence bond
(RVB) character. We first consider a system of N two level spins in a cavity
with only one spin in the excited state. This initial state is a linear
combination of a dark state and a bright state. We point out the dark state is
a coherent superposition of singlets with resonating valence bond character. We
show that the coupling to the photon mode takes the spin system into a mixed
state with an entangled density matrix. We next consider an initial state with
half of the spins in the excited state. We show that there is a non-zero
probability for this to collapse into a dark state with RVB character. In the
lossy cavity limit, if no photon is detected within several decay time periods,
we may deduce that the spin system has collapsed onto the dark RVB state. We
show that the probability for this scales as 2/N, making it possible to
generate RVB states of 20 spins or more.


title: Vastness properties of automorphism groups of RAAGs

abstract:
  Outer automorphism groups of RAAGs, denoted $Out(A_\Gamma)$, interpolate
between $Out(F_n)$ and $GL_n(\mathbb{Z})$. We consider several vastness
properties for which $Out(F_n)$ behaves very differently from
$GL_n(\mathbb{Z})$: virtually mapping onto all finite groups, SQ-universality,
virtually having an infinite dimensional space of homogeneous quasimorphisms,
and not being boundedly generated.
  We give a neccessary and sufficient condition in terms of the defining graph
$\Gamma$ for each of these properties to hold. Notably, the condition for all
four properties is the same, meaning $Out(A_\Gamma)$ will either satisfy all
four, or none. In proving this result, we describe conditions on $\Gamma$ that
imply $Out(A_\Gamma)$ is large.
  Techniques used in this work are then applied to the case of McCool groups,
defined as subgroups of $Out(F_n)$ that preserve a given family of conjugacy
classes. In particular we show that any McCool group that is not virtually
abelian virtually maps onto all finite groups, is SQ-universal, is not
boundedly generated, and has a finite index subgroup whose space of homogeneous
quasimorphisms is infinite dimensional.


title:
A Glimpse Far into the Future: Understanding Long-term Crowd Worker
  Quality

abstract:
  Microtask crowdsourcing is increasingly critical to the creation of extremely
large datasets. As a result, crowd workers spend weeks or months repeating the
exact same tasks, making it necessary to understand their behavior over these
long periods of time. We utilize three large, longitudinal datasets of nine
million annotations collected from Amazon Mechanical Turk to examine claims
that workers fatigue or satisfice over these long periods, producing lower
quality work. We find that, contrary to these claims, workers are extremely
stable in their quality over the entire period. To understand whether workers
set their quality based on the task's requirements for acceptance, we then
perform an experiment where we vary the required quality for a large
crowdsourcing task. Workers did not adjust their quality based on the
acceptance threshold: workers who were above the threshold continued working at
their usual quality level, and workers below the threshold self-selected
themselves out of the task. Capitalizing on this consistency, we demonstrate
that it is possible to predict workers' long-term quality using just a glimpse
of their quality on the first five tasks.


title:
Single variant bottleneck in the early dynamics of H. influenzae
  bacteremia in neonatal rats questions the theory of independent action

abstract:
  There is an abundance of information about the genetic basis, physiological
and molecular mechanisms of bacterial pathogenesis. In contrast, relatively
little is known about population dynamic processes, by which bacteria colonize
hosts and invade tissues and cells and thereby cause disease. In an article
published in 1978, Moxon and Murphy presented evidence that, when inoculated
intranasally with a mixture streptomycin sensitive and resistant (Sm$^S$ and
Sm$^R$) and otherwise isogenic stains of Haemophilus influenzae type b (Hib),
neonatal rats develop a bacteremic infection that often is dominated by only
one strain, Sm$^S$ or Sm$^R$. After rulling out other possibilities through
years of related experiments, the field seems to have settled on a plausible
explanation for this phenomenon: the first bacterium to invade the host
activates the host immune response that `shuts the door' on the second invading
strain. To explore this hypothesis in a necessarily quantitative way, we
modeled this process with a set of mixed stochastic and deterministic
differential equations. Our analysis of the properties of this model with
realistic parameters suggests that this hypothesis cannot explain the
experimental results of Moxon and Murphy, and in particular the observed
relationship between the frequency of different types of blood infections
(bacteremias) and the inoculum size. We propose modifications to the model that
come closer to explaining these data. However, the modified and better fitting
model contradicts the common theory of independent action of individual
bacteria in establishing infections. We discuss the implications of these
results.


title: G-corks & Heegaard Floer Homology

abstract:
  Recently Auckly-Kim-Melvin-Ruberman showed that for any finite subgroup G of
SO(4) there exists a contractible 4-manifold with an effective G-action on its
boundary so that the twists associated to the non-trivial elements of G do not
extend to diffeomorphisms of the entire manifold. We use a Heegaard Floer
theoretic argument originating in work of Akbulut-Karakurt to give a different
proof of this phenomenon.


title:
Transverse velocity shifts in protostellar jets: rotation or velocity
  asymmetries?

abstract:
  Observations of several protostellar jets show systematic differences in
radial velocity transverse to the jet propagation direction, which have been
interpreted as evidence of rotation in the jets. In this paper we discuss the
origin of these velocity shifts, and show that they could be originated by
rotation in the flow, or by side to side asymmetries in the shock velocity,
which could be due to asymmetries in the jet ejection velocity/density or in
the ambient medium. For typical poloidal jet velocities (~ 100-200 km/s), an
asymmetry >~ 10% can produce velocity shifts comparable to those observed. We
also present three dimensional numerical simulations of rotating, precessing
and asymmetric jets, and show that, even though for a given jet there is a
clear degeneracy between these effects, a statistical analysis of jets with
different inclination angles can help to distinguish between the alternative
origins of transverse velocity shifts. Our analysis indicate that side to side
velocities asymmetries could represent an important contribution to transverse
velocity shifts, being the most important contributor for large jet inclination
angles (with respect the the plane of the sky), and can not be neglected when
interpreting the observations.


title: Model Selection Framework for Graph-based data

abstract:
  Graphs are powerful abstractions for capturing complex relationships in
diverse application settings. An active area of research focuses on theoretical
models that define the generative mechanism of a graph. Yet given the
complexity and inherent noise in real datasets, it is still very challenging to
identify the best model for a given observed graph. We discuss a framework for
graph model selection that leverages a long list of graph topological
properties and a random forest classifier to learn and classify different graph
instances. We fully characterize the discriminative power of our approach as we
sweep through the parameter space of two generative models, the Erdos-Renyi and
the stochastic block model. We show that our approach gets very close to known
theoretical bounds and we provide insight on which topological features play a
critical discriminating role.


title:
SHiP: a new facility with a dedicated detector for studying $\nu_\tau$
  properties and nucleon structure functions

abstract:
  SHIP is a new general purpose fixed target facility, proposed at the CERN SPS
accelerator. In five years, $2\times 10^{20}$ protons of 400 GeV/c momentum
will be dumped on a Molybdenum target. A detector downstream of the target will
allow a search to made for long-lived particles with masses below O(10)
GeV/c$^2$ foreseen in several extensions of the Standard Model. Another
dedicated detector will allow the study of active neutrino cross-sections and
angular distributions. The neutrino detector consists of an emulsion target,
based on the Emulsion Cloud Chamber technology fruitfully employed in the OPERA
experiment. The Emulsion Cloud Chamber will be placed in a magnetic field, with
the so-called Compact Emulsion Spectrometer, a few cm thick chamber for the
charge and momentum measurement of hadrons. This will provide the leptonic
number measurement also in the hadronic tau decay channels. The detector will
be hybrid, using nuclear emulsions and electronic detectors for the time stamp
of the events and the measurement of the muon momentum. The muon system will
also be based on the design of the one used in the OPERA experiment.


title: Visual Stability Prediction and Its Application to Manipulation

abstract:
  Understanding physical phenomena is a key competence that enables humans and
animals to act and interact under uncertain perception in previously unseen
environments containing novel objects and their configurations. Developmental
psychology has shown that such skills are acquired by infants from observations
at a very early stage.
  In this paper, we contrast a more traditional approach of taking a
model-based route with explicit 3D representations and physical simulation by
an {\em end-to-end} approach that directly predicts stability from appearance.
We ask the question if and to what extent and quality such a skill can directly
be acquired in a data-driven way---bypassing the need for an explicit
simulation at run-time.
  We present a learning-based approach based on simulated data that predicts
stability of towers comprised of wooden blocks under different conditions and
quantities related to the potential fall of the towers. We first evaluate the
approach on synthetic data and compared the results to human judgments on the
same stimuli. Further, we extend this approach to reason about future states of
such towers that in turn enables successful stacking.


title: A Bayesian approach to denoising of single-photon binary images

abstract:
  This paper discusses new methods for processing images in the photon-limited
regime where the number of photons per pixel is binary. We present a new
Bayesian denoising method for binary, single-photon images. Each pixel
measurement is assumed to follow a Bernoulli distribution whose mean is related
by a nonlinear function to the underlying intensity value to be recovered.
Adopting a Bayesian approach, we assign the unknown intensity field a
smoothness promoting spatial and potentially temporal prior while enforcing the
positivity of the intensity. A stochastic simulation method is then used to
sample the resulting joint posterior distribution and estimate the unknown
intensity, as well as the regularization parameters. We show that this new
unsupervised denoising method can also be used to analyze images corrupted by
Poisson noise. The proposed algorithm is compared to state-of-the art denoising
techniques dedicated to photon-limited images using synthetic and real
single-photon measurements. The results presented illustrate the potential
benefits of the proposed methodology for photon-limited imaging, in particular
with non photonnumber resolving detectors.


title: Vortex structure in superfluid color-flavor locked quark matter

abstract:
  The core region of a neutron star may feature quark matter in the
color-flavor- locked (CFL) phase. The CFL condensate breaks the baryon number
symmetry, such that the phenomenon of superfluidity arises. If the core of the
star is rotating, vortices will form in the superfluid, carrying the quanta of
angular momentum. In a previous study we have solved the question of stability
of these vortices, where we found numerical proof of a conjectured instability,
according to which superfluid vortices will decay into an arrangement of
so-called semi-superfluid fluxtubes. Here we report first results of an
extension of our framework that allows us to study multi-vortex dynamics. This
will in turn enable us to investigate the structure of semi-superfluid string
lattices, which could be relevant to study pinning phenomena at the boundary of
the core.


title:
Gravitational redshift and asymmetric redshift-space distortions for
  stacked clusters

abstract:
  We derive the expression for the observed redshift in the weak field limit in
the observer's past light cone, including all relativistic terms up to second
order in velocity. We then apply it to compute the cluster-galaxy
cross-correlation functions (CGCF) using N-body simulations. The CGCF is
asymmetric along the line of sight (LOS) owing to the presence of the small
second order terms such as the gravitational redshift (GRedshift). We identify
two systematics in the modelling of the GRedshift signal in stacked clusters.
First, it is affected by the morphology of dark matter haloes and the
large-scale cosmic-web. The non-spherical distribution of galaxies around the
central halo and the presence of neighbouring clusters systematically reduce
the GRedshift signal. This bias is approximately 20% for $M_{\rm min}\simeq
10^{14} {\rm M_{\odot}}/h$, and is more than 50% for haloes with $M_{\rm
min}\simeq 2\times 10^{13} {\rm M_{\odot}}/h$ at $r>$4 Mpc/$h$. Second, the
best-fit gravitational redshift profiles as well as the profiles of all other
relativistic terms are found to be significantly different in velocity space
compared to their real space versions. We discuss some subtleties relating to
these effects in velocity space. We also find that the S/N of the GRedshift
signal increases with decreasing halo mass.


title: The Delta Conjecture at $q=1$

abstract:
  We use a weight-preserving, sign-reversing involution to find a combinatorial
expansion of $\Delta_{e_k} e_n$ at $q=1$ in terms of the elementary symmetric
function basis. We then use a weight-preserving bijection to prove the Delta
Conjecture at $q=1$. The method of proof provides a variety of structures which
can compute the inner product of $\Delta_{e_k} e_n|_{q=1}$ with any symmetric
function.


title:
Phase-field modeling of chemical control of polarization stability and
  switching dynamics in ferroelectric thin film

abstract:
  Phase-field simulation (PFS) have revolutionized the understanding of domain
structure and switching behavior in ferroelectric thin films and ceramics.
Generally, PFS is based on solution of a (set) of Ginzburg-Landau equations for
a defined order parameter field(s) under physical boundary conditions (BCs) of
fixed potential or charge. While well-matched to the interfaces in bulk
materials and devices, these BCs are generally not applicable to free
ferroelectric surfaces. Here, we developed a self-consistent phase-field model
with boundary conditions based on electrochemical equilibria. We chose
Pb(Zr0.2Ti0.8)O3 ultrathin film consisting of (001) oriented single tetragonal
domain (Pz) as a model system, and systematically studied the effects of oxygen
partial pressure, temperature and surface ion on the ferroelectric state, and
compared it with the case of complete screening. We have further explored the
polarization switching induced by the oxygen partial pressure and observed
pronounced size effect induced by chemical screening. Our work thus helps to
understand the emergent phenomena in ferroelectric thin films brought about by
the electrochemical ionic surface compensations.


title:
Characterization of high-temperature performance of cesium vapor cells
  with anti-relaxation coating

abstract:
  Vapor cells with antirelaxation coating are widely used in modern atomic
physics experiments due to the coating's ability to maintain the atoms' spin
polarization during wall collisions. We characterize the performance of vapor
cells with different coating materials by measuring longitudinal spin
relaxation and vapor density at temperatures up to 95{\deg}C. We found that the
spin-projection-noise-limited sensitivity for atomic magnetometers with such
cells improves with temperature, which demonstrates the potential of
antirelaxation coated cells in applications of future high-sensitivity
magnetometers.


title: Psi(2S) Production at the LHC

abstract:
  We calculate the production of $\psi(2S)$ and the pertinent double ratio of
its nuclear modification factor ($R_{\rm AA}$) over that of the $J/\psi$ in
Pb-Pb collisions at the LHC. Based on a transport model with temperature
dependent reaction rates, a sequential regeneration pattern emerges: the larger
$\psi(2S)$ width, relative to the $J/\psi$, around and below the critical
temperature, implies that most of the $\psi(2S)$ states are regenerated later
in the evolution of the fireball. This has noticeable consequences for the
transverse-momentum ($p_T$) spectra of the regenerated charmonia. While the
total yield of $\psi(2S)$ meson remains smaller than those of $J/\psi$'s, their
harder $p_T$ spectra can produce a double ratio above unity for a $p_T>3$GeV
cut, as applied by the CMS collaboration. A significant uncertainty in our
calculations is associated with the values of the temperature where most of the
$\psi(2S)$ regeneration occurs, the quantitative temperature dependence of its
inelastic width.


title:
Iteration-complexity of gradient, subgradient and proximal point methods
  on Riemannian manifolds

abstract:
  This paper considers optimization problems on Riemannian manifolds and
analyzes iteration-complexity for gradient and subgradient methods on manifolds
with non-negative curvature. By using tools from the Riemannian convex analysis
and exploring directly the tangent space of the manifold, we obtain different
iteration-complexity bounds for the aforementioned methods, complementing and
improving related results. Moreover, we also establish iteration-complexity
bound for the proximal point method on Hadamard manifolds.


title:
Phase Quantization Study of Spatial Light Modulator for Extreme High
  contrast Imaging

abstract:
  Direct imaging of exoplanets by reflected starlight is extremely challenging
due to the large luminosity ratio to the primary star. Wave-front control is a
critical technique to attenuate the speckle noise in order to achieve an
extremely high contrast. We present a phase quantization study of a spatial
light modulator for wave front control to meet the contrast requirement of
detection of a terrestrial planet in the habitable zone of a solar-type star.
We perform the numerical simulation by employing the SLM with different phase
accuracy and actuator numbers, which are related to the achievable contrast. We
use an optimization algorithm to solve the quantization problems that is
matched to the controllable phase step of the SLM. Two optical configurations
are discussed with the SLM located before and after the coronagraph focal plane
mask. The simulation result has constrained the specification for SLM phase
accuracy in the above two optical configurations. Finally, we have demonstrated
that a SLM with more actuators can deliver a competitive contrast performance
to that by using a deformable mirror.