title:
Existence of multi-bump solutions to biharmonic operator with critical
  exponential growth in $\mathbb{R}^4$

abstract:
  Using variational methods, we establish existence of multi-bump solutions for
the following class of problems $$
  \left\{
  \begin{array}{l}
  \Delta^2 u +(\lambda V(x)+1)u = f(u), \quad \mbox{in} \quad \mathbb{R}^{4},
  u \in H^{2}(\mathbb{R}^{4}),
  \end{array}
  \right.
  $$ where $\Delta^2$ is the biharmonic operator, $f$ is a continuous function
with critical exponential growth and $V : \mathbb{R}^4 \rightarrow \mathbb{R}$
is a continuous function verifying some conditions.


title: Noisy Hypotheses in the Age of Discovery Science

abstract:
  We draw attention to one specific issue raised by Ioannidis (2005), that of
very many hypotheses being tested in a given field of investigation. To better
isolate the problem that arises in this (massive) multiple testing scenario, we
consider a utopian setting where the hypotheses are tested with no additional
bias. We show that, as the number of hypotheses being tested becomes much
larger than the discoveries to be made, it becomes impossible to reliably
identify true discoveries. This phenomenon, well-known to statisticians working
in the field of multiple testing, puts in jeopardy any naive pursuit in (pure)
discovery science.


title: Evaluating Generating Functions for Periodic Multiple Polylogarithms

abstract:
  The goal of the paper is to give a systematic way to numerically evaluate the
generating function of a periodic multiple polylogarithm using a Chen-Fliess
series with a rational generating series. The idea is to realize the
corresponding Chen-Fliess series as a bilinear dynamical system. A standard
form for such a realization is given. The method is also generalized to the
case where the multiple polylogarithm has non-periodic components. This allows
one, for instance, to numerically validate the Hoffman conjecture. Finally, a
setting in terms of dendriform algebras is provided.


title: Problem optymalizacyjny de Finettiego dla proces\'ow L\'evy'ego

abstract: We give a review of the state of the art with regard to the dividend problem.


title: Quasinormal modes and the phase structure of strongly coupled matter

abstract:
  We investigate the poles of the retarded Green's functions of strongly
coupled field theories exhibiting a variety of phase structures from a
crossover up to different first order phase transitions. These theories are
modeled by a dual gravitational description. The poles of the holographic
Green's functions appear at the frequencies of the quasinormal modes of the
dual black hole background. We focus on quantifying linearized level dynamical
response of the system in the critical region of phase diagram. Generically
non-hydrodynamic degrees of freedom are important for the low energy physics in
the vicinity of a phase transition. For a model with linear confinement in the
meson spectrum we find degeneracy of hydrodynamic and non-hydrodynamic modes
close to the minimal black hole temperature, and we establish a region of
temperatures with unstable non-hydrodynamic modes in a branch of black hole
solutions.


title:
Model Comparison of a Data-Driven and a Physical Model for Simulating
  HVAC Systems

abstract:
  Commercial buildings are responsible for a large fraction of energy
consumption in developed countries, and therefore are targets of energy
efficiency programs. Motivated by the large inherent thermal inertia of
buildings, the power consumption can be flexibly scheduled without compromising
occupant comfort. This temporal flexibility offers opportunities for the
provision of frequency regulation to support grid stability. To realize energy
savings and frequency regulation, it is of prime importance to identify a
realistic model for the temperature dynamics of a building. We identify a low-
dimensional data-driven model and a high-dimensional physics- based model for
different spatial granularities and temporal seasons based on a case study of
an entire floor of Sutardja Dai Hall, an office building on the University of
California, Berkeley campus. A comparison of these contrasting models shows
that, despite the higher forecasting accuracy of the physics-based model, both
models perform almost equally well for energy efficient control. We conclude
that the data-driven model is more amenable to controller design due to its low
complexity, and could serve as a substitution for highly complex physics- based
models with an insignificant loss of prediction accuracy for many applications.
On the other hand, our physics-based approach is more suitable for modeling
buildings with finer spatial granularities.


title: The Lepton Flavour Violating Higgs Decays at the HL-LHC and the ILC

abstract:
  Run-I results from the CMS collaboration show an excess of events in the
decay $h \to \mu \tau_e$ with a local significances of 2.4$\sigma$. This could
be the first hint of flavour violation in the Higgs sector. We summarise the
bounds on the flavour violating Yukawa couplings from direct searches, low
energy measurements and projected future experiments. We discuss the
sensitivity of upcoming HL-LHC runs and future lepton colliders in measuring
lepton-flavour violating couplings using an effective field theory framework.
For the HL-LHC we find limits on BR($h\to \mu \tau$) and BR$(h\to e \tau)
\lesssim \mathcal{O}(0.5)\%$ and on BR($h \to e \mu) \lesssim
\mathcal{O}(0.02)\%$. For an ILC with center-of-mass energy of 1 TeV we expect
BR($h \to e \tau$) and BR($h\to \mu \tau$) to be measurable down to
$\mathcal{O}(0.2)\%$.


title: Katyusha: The First Direct Acceleration of Stochastic Gradient Methods

abstract:
  Nesterov's momentum trick is famously known for accelerating gradient
descent, and has been proven useful in building fast iterative algorithms.
However, in the stochastic setting, counterexamples exist and prevent
Nesterov's momentum from providing similar acceleration, even if the underlying
problem is convex and finite-sum.
  We introduce $\mathtt{Katyusha}$, a direct, primal-only stochastic gradient
method to fix this issue. In convex finite-sum stochastic optimization,
$\mathtt{Katyusha}$ has an optimal accelerated convergence rate, and enjoys an
optimal parallel linear speedup in the mini-batch setting.
  The main ingredient is $\textit{Katyusha momentum}$, a novel "negative
momentum" on top of Nesterov's momentum. It can be incorporated into a
variance-reduction based algorithm and speed it up, both in terms of
$\textit{sequential and parallel}$ performance. Since variance reduction has
been successfully applied to a growing list of practical problems, our paper
suggests that in each of such cases, one could potentially try to give Katyusha
a hug.


title: The structure of combinatorial Markov processes

abstract:
  Every exchangeable Feller process taking values in a suitably nice
combinatorial state space can be constructed by a system of iterated random
Lipschitz functions. In discrete time, the construction proceeds by iterated
application of independent, identically distributed functions, while in
continuous time the random functions occur as the atoms of a time homogeneous
Poisson point process. We further show that every exchangeable Feller process
projects to a Feller process in an appropriate limit space, akin to the
projection of partition-valued processes into the ranked-simplex and
graph-valued processes into the space of graph limits. Together, our main
theorems establish common structural features shared by all exchangeable
combinatorial Feller processes, regardless of the dynamics or resident state
space, thereby generalizing behaviors previously observed for exchangeable
coalescent and fragmentation processes as well as other combinatorial
stochastic processes. If, in addition, an exchangeable Feller process evolves
on a state space satisfying the $n$-disjoint amalgamation property for all
$n\geq1$, then its jump measure can be decomposed explicitly in the sense of
L\'evy--It\^o--Khintchine.


title:
Transferring Learned Microcalcification Group Detection from 2D
  Mammography to 3D Digital Breast Tomosynthesis Using a Hierarchical Model and
  Scope-based Normalization Features

abstract:
  A novel hierarchical model is introduced to solve a general problem of
detecting groups of similar objects. Under this model, detection of groups is
performed in hierarchically organized layers while each layer represents a
scope for target objects. The processing of these layers involves sequential
extraction of appearance features for an individual object, consistency
measurement features for nearby objects, and finally the distribution features
for all objects within the group. Using the concept of scope-based
normalization, the extracted features not only enhance local contrast of an
individual object, but also provide consistent characterization for all related
objects. As an example, a microcalcification group detection system for 2D
mammography was developed, and then the learned model was transferred to 3D
digital breast tomosynthesis without any retraining or fine-tuning. The
detection system demonstrated state-of-the-art performance and detected 96% of
cancerous lesions at the rate of 1.2 false positives per volume as measured on
an independent tomosynthesis test set.


title: Lie subalgebras of the matrix quantum pseudo differential operators

abstract:
  We give a complete description of the anti-involutions that preserve the
principal gradation of the algebra of matrix quantum pseudodifferential
operators and we describe the Lie subalgebras of its minus fixed points.


title:
Solutions with a bounded support promote permanence of a distributed
  replicator equation

abstract:
  The now classical replicator equation describes a wide variety of biological
phenomena, including those in theoretical genetics, evolutionary game theory,
or in the theories of the origin of life. Among other questions, the permanence
of the replicator equation is well studied in the local, well-mixed case.
Inasmuch as the spatial heterogeneities are key to understanding the species
coexistence at least in some cases, it is important to supplement the classical
theory of the non-distributed replicator equation with a spatially explicit
framework. One possible approach, motivated by the porous medium equation, is
introduced. It is shown that the solutions to the spatially heterogeneous
replicator equation may evolve to equilibrium states that have a bounded
support, and, moreover, that these solutions are of paramount importance for
the overall system permanence, which is shown to be a more commonplace
phenomenon for the spatially explicit equation if compared with the local
model.


title: Tutorial to SARAH

abstract:
  I give in this brief tutorial a short practical introduction to the
Mathematica package SARAH. First, it is shown how an existing model file can be
changed to implement a new model in SARAH. In the second part, masses, vertices
and renormalisation group equations are calculated with SARAH. Finally, the
main commands to generate model files and output for other tools are
summarised.


title:
Efficient Multi-Scale 3D CNN with Fully Connected CRF for Accurate Brain
  Lesion Segmentation

abstract:
  We propose a dual pathway, 11-layers deep, three-dimensional Convolutional
Neural Network for the challenging task of brain lesion segmentation. The
devised architecture is the result of an in-depth analysis of the limitations
of current networks proposed for similar applications. To overcome the
computational burden of processing 3D medical scans, we have devised an
efficient and effective dense training scheme which joins the processing of
adjacent image patches into one pass through the network while automatically
adapting to the inherent class imbalance present in the data. Further, we
analyze the development of deeper, thus more discriminative 3D CNNs. In order
to incorporate both local and larger contextual information, we employ a dual
pathway architecture that processes the input images at multiple scales
simultaneously. For post-processing of the network's soft segmentation, we use
a 3D fully connected Conditional Random Field which effectively removes false
positives. Our pipeline is extensively evaluated on three challenging tasks of
lesion segmentation in multi-channel MRI patient data with traumatic brain
injuries, brain tumors, and ischemic stroke. We improve on the state-of-the-art
for all three applications, with top ranking performance on the public
benchmarks BRATS 2015 and ISLES 2015. Our method is computationally efficient,
which allows its adoption in a variety of research and clinical settings. The
source code of our implementation is made publicly available.


title:
Solar models in light of new high metallicity measurements from solar
  wind data

abstract:
  We study the impact of new metallicity measurements, from solar wind data, on
the solar model. The "solar modelling problem" refers to the persisting
discrepancy between helioseismological observations and predictions of solar
models computed implementing state-of-the-art photospheric abundances. We
critically reassess the problem, in particular considering the new set of
abundances of von Steiger \& Zurbuchen 2016, determined through the \textit{in
situ} collection of solar wind samples from polar coronal holes. This new set
of abundances indicates a solar metallicity $Z_{\odot} \geq 0.0196 \pm 0.0014$,
significantly higher than the currently established value. The new values hint
at an abundance of volatile elements (i.e. C, N, O, Ne) close to previous
results of Grevesse \& Sauval 1998, whereas the abundance of refractory
elements (i.e. Mg, Si, S, Fe) is considerably increased. Using the Linear Solar
Model formalism, we determine the variation of helioseismological observables
in response to the changes in elemental abundances, in order to explore the
consistency of these new measurements with constraints from helioseismology. We
find that, for observables that are particularly sensitive to the abundance of
volatile elements, in particular the radius of the convective zone boundary
(CZB) and the sound speed around the radius of CZB, improved agreement over
previous models is obtained. Conversely, the high abundance of refractories
correlates with a higher core temperature, resulting in an overproduction of
neutrinos and a huge increase in the surface Helium abundance. We conclude that
the "solar modelling problem" remains unsolved.


title:
Plasma Relaxation and Topological Aspects in
  Electronmagnetohydrodynamics

abstract:
  Parker's formulation of isotopological plasma relaxation process toward
minimum magnetics energy states in magnetohydrodynamics (MHD) is extended to
electron MHD (EMHD).
  The lower bound on magnetic energy in EMHD is determined by both the magnetic
field and the electron vorticity field topologies, and is shown to be reduced
further in EMHD by an amount proportional to the sum of total electron-flow
kinetic energy and total electron-flow enstrophy. The EMHD Beltrami condition
becomes equivalent to the potential vorticity conservation equation in
two-dimensional (2D) hydrodynamics, and the torsion coefficient and turns out
to be proportional to potential vorticity. The winding pattern of the magnetic
field lines appears to evolve therefore in the same way as "potential
vorticity" lines in 2D hydrodynamics.


title: Document Neural Autoregressive Distribution Estimation

abstract:
  We present an approach based on feed-forward neural networks for learning the
distribution of textual documents. This approach is inspired by the Neural
Autoregressive Distribution Estimator(NADE) model, which has been shown to be a
good estimator of the distribution of discrete-valued igh-dimensional vectors.
In this paper, we present how NADE can successfully be adapted to the case of
textual data, retaining from NADE the property that sampling or computing the
probability of observations can be done exactly and efficiently. The approach
can also be used to learn deep representations of documents that are
competitive to those learned by the alternative topic modeling approaches.
Finally, we describe how the approach can be combined with a regular neural
network N-gram model and substantially improve its performance, by making its
learned representation sensitive to the larger, document-specific context.


title:
You Really Need A Good Ruler to Measure Caching Performance in
  Information-Centric Networks

abstract:
  Information-centric networks are an interesting new paradigm for distributing
content on the Internet. They bring up many research challenges, such as
addressing content by name, securing content, and wide-spread caching of
content. Caching has caught a lot of attention in the research community, but a
lot of the work suffers from a poor understanding of the different metrics with
which caching performance can be measured. In this paper we not only present a
comprehensive overview of different caching metrics that have been proposed for
information-centric networks, but also propose the coupling factor as a new
metric to capture the relation- ship between content popularity and network
topology. As we show, many commonly used metrics have several failure modes
which are largely ignored in literature. We identify these problems and propose
remedies and new metrics to address these failures. Our work highlights the
fundamental differences between information-centric caches and "traditional"
cache networks and we demonstrate the need for a systematic understanding of
the metrics for information- centric caching. We also discuss how experimental
work should be done when evaluating networks of caches.


title:
Electro-Optical Radiation of a Charged Particle in a Single Laser Beam
  Field

abstract:
  A peculiar radiation arising as a result of radiation interference of
nonlinear oscillators excited by a monochromatic plane wave field of the
incident particle is described. The radiation properties are determined by the
fact that a phase of each oscillator radiation fields is synchronized by a wave
field, while the radiation itself occurs due to the particle field influence on
the oscillators. The consideration is performed for a thin film with negligible
density effect. It is supposed that the contribution is given only by a
long-wave part of the Weizsacker spectrum for which nonlinear polarization
coefficients of medium are large.


title:
Quantum Theory of Half-integer Spin Free Particles from the Perspective
  of the Majorana Equation

abstract:
  In this study, the Majorana equation for particles with arbitrary spin is
solved for a half-integer spin free particle. The solution for the fundamental
state, corresponding to the reference frame in which the particle is at rest,
is compared with that obtained using the Dirac equation, especially as regards
the approximation in the relativistic limit, in which the speed of the particle
is close to that of light. Furthermore, the solutions that Majorana defines
unphysical, proving that their occupation probability increases with the
particle velocity, are taken into consideration. The anomalous behavior
exhibited by these states also shows that for high-energy particles with small
mass, transitions from a bradyonic state to a tachyonic state become possible.


title: Distributed Randomized Control for Demand Dispatch

abstract:
  The paper concerns design of control systems for Demand Dispatch to obtain
ancillary services to the power grid by harnessing inherent flexibility in many
loads. The role of "local intelligence" at the load has been advocated in prior
work, randomized local controllers that manifest this intelligence are
convenient for loads with a finite number of states. The present work
introduces two new design techniques for these randomized controllers:
  (i) The Individual Perspective Design (IPD) is based on the solution to a
one-dimensional family of Markov Decision Processes, whose objective function
is formulated from the point of view of a single load. The family of dynamic
programming equation appears complex, but it is shown that it is obtained
through the solution of a single ordinary differential equation.
  (ii) The System Perspective Design (SPD) is motivated by a single objective
of the grid operator: Passivity of any linearization of the aggregate
input-output model. A solution is obtained that can again be computed through
the solution of a single ordinary differential equation.
  Numerical results complement these theoretical results.


title: A computational high-throughput search for new ternary superalloys

abstract:
  In 2006, a novel cobalt-based superalloy was discovered [1] with mechanical
properties better than some conventional nickel-based superalloys. As with
conventional superalloys, its high performance arises from the
precipitate-hardening effect of a coherent L1$_2$ phase, which is in two-phase
equilibrium with the fcc matrix. Inspired by this unexpected discovery of an
L1$_2$ ternary phase, we performed a first-principles search through 2224
ternary metallic systems for analogous precipitate-hardening phases of the form
$X_{3}$[$A_{0.5}, B_{0.5}$], where $X$ = Ni, Co, or Fe, and [$A,B$] = Li, Be,
Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn Ga, Sr, Y, Zr, Nb, Mo,
Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, or Tl.
We found 102 systems that have a smaller decomposition energy and a lower
formation enthalpy than the Co$_{3}$(Al, W) superalloy. They have a stable
two-phase equilibrium with the host matrix within the concentration range
$0<x<1$ ($X_{3}$[$A_{x}, B_{1-x}$]) and have a relative lattice mismatch with
the host matrix of less than or equal to 5%. These new candidates, narrowed
from 2224 systems, suggest possible experimental exploration for identifying
new superalloys. Of these 102 systems, 37 are new; they have no reported phase
diagrams in standard databases. Based on cost, experimental difficulty, and
toxicity, we limit these 37 to a shorter list of six promising candidates of
immediate interest. Our calculations are consistent with current experimental
literature where data exists.


title: On the origin of the CDDR violation

abstract:
  The investigation of any violation in the Cosmic Distance Duality Relation
(CDDR) is one of the most important sources of investigation for a new physic.
In this paper we propose a new method to find the origin of a possible
violation on the CDDR. Such violation is defined from the equation
$\frac{d_L}{d_A(1+z)^2} = \eta$, with $\eta \neq 1$. We analyze the
observational constraints from SNIa, BAO and $f_{gas}$ for the parameter $\eta$
using three different parameterizations. We create three data sets with the
following combinations: (Set I) $d_L$ data from SNIa and $d_A$ data from BAO
measurements, (Set II) $d_L$ data from $f_{gas}$ and $d_A$ from BAO
measurements and (Set III) $d_L$ from SNIa and $d_A$ from $f_{gas}$
measurements. The sets have 18 points and a redshift difference between the
observational pairs of $\Delta z \leq 0.08$. It is found that the difference
between Sets I and II is up to five times higher than Sets I and III, what
suggest that a violation in the CDDR come from a new physics related with the
angular diameter distance.


title: Circuits and Hurwitz action in finite root systems

abstract:
  In a finite real reflection group, two factorizations of a Coxeter element
into an arbitrary number of reflections are shown to lie in the same orbit
under the Hurwitz action if and only if they use the same multiset of conjugacy
classes. The proof makes use of a surprising lemma, derived from a
classification of the minimal linear dependences (matroid circuits) in finite
root systems: any set of roots forming a minimal linear dependence with
positive coefficients has a disconnected graph of pairwise acuteness.


title:
Coherent-state constellations and polar codes for thermal Gaussian
  channels

abstract:
  Optical communication channels are ultimately quantum-mechanical in nature,
and we must therefore look beyond classical information theory to determine
their communication capacity as well as to find efficient encoding and decoding
schemes of the highest rates. Thermal channels, which arise from linear
coupling of the field to a thermal environment, are of particular practical
relevance; their classical capacity has been recently established, but their
quantum capacity remains unknown. While the capacity sets the ultimate limit on
reliable communication rates, it does not promise that such rates are
achievable by practical means. Here we construct efficiently encodable codes
for thermal channels which achieve the classical capacity and the so-called
Gaussian coherent information for transmission of classical and quantum
information, respectively. Our codes are based on combining polar codes with a
discretization of the channel input into a finite "constellation" of coherent
states. Encoding of classical information can be done using linear optics.


title: Polaritonic Rabi and Josephson Oscillations

abstract:
  The dynamics of coupled condensates is a wide-encompassing problem with
relevance to superconductors, BECs in traps, superfluids, etc. Here, we provide
a unified picture of this fundamental problem that includes i) detuning of the
free energies, ii) different self-interaction strengths and iii) finite
lifetime of the modes. At such, this is particularly relevant for the dynamics
of polaritons, both for their internal dynamics between their light and matter
constituents, as well as for the more conventional dynamics of two spatially
separated condensates. Polaritons are short-lived, interact only through their
material fraction and are easily detuned. At such, they bring several
variations to their atomic counterpart. We show that the combination of these
parameters results in important twists to the phenomenology of the Josephson
effect, such as the behaviour of the relative phase (running or oscillating) or
the occurrence of self-trapping. We undertake a comprehensive stability
analysis of the fixed points on a normalized Bloch sphere, that allows us to
provide a generalized criterion to identify the Rabi and Josephson regimes in
presence of detuning and decay.


title: Anomalous diffusion and FRAP dynamics in the random comb model

abstract:
  We address the problem of diffusion on a comb whose teeth display a varying
length. Specifically, the length $\ell$ of each tooth is drawn from a
probability distribution displaying the large-$\ell$ behavior $P(\ell) \sim
\ell^{-(1+\alpha)}$ ($\alpha>0$). Our method is based on the mean-field
description provided by the well-tested CTRW approach for the random comb
model, and the obtained analytical result for the diffusion coefficient is
confirmed by numerical simulations. We subsequently incorporate retardation
effects arising from binding/unbinding kinetics into our model and obtain a
scaling law characterizing the corresponding change in the diffusion
coefficient. Finally, our results for the diffusion coefficient are used as an
input to compute concentration recovery curves mimicking FRAP experiments in
comb-like geometries such as spiny dendrites. We show that such curves cannot
be fitted perfectly by a model based on scaled Brownian motion, i.e., a
standard diffusion equation with a time-dependent diffusion coefficient.
However, differences between the exact curves and such fits are small, thereby
providing justification for the practical use of models relying on scaled
Brownian motion as a fitting procedure for recovery curves arising from
particle diffusion in comb-like systems.


title:
Producing Virtually Defect Free Nanoscale Ripples by Ion Bombardment of
  Rocked Solid Surfaces

abstract:
  Bombardment of a solid surface with a broad, obliquely-incident ion beam
frequently produces nanoscale surface ripples. The primary obstacle that
prevents the adoption of ion bombardment as a nano-fabrication tool is the high
density of defects in the patterns that are typically formed. Our simulations
indicate that ion bombardment can produce nearly defect free ripples on the
surface of an elemental solid if the sample is concurrently and periodically
rocked about an axis orthogonal to the surface normal and the incident beam
direction. We also investigate the conditions necessary for rocking to produce
highly ordered ripples and discuss how the results of our simulations can be
reproduced experimentally.


title:
First-principles study of ferroelectricity induced by p-d hybridization
  in ferrimagnetic NiFe2O4

abstract:
  We investigate the ferrimagnetism and ferroelectricity of bulk NiFe$_2$O$_4$
with tetragonal $P4_122$ ~symmetry by means of density functional calculations
using generalized gradient approximation + Hubbard $U$ approach. Special
attention is paid to finding the most energetically favorable configuration on
magnetic ordering and further calculating the reliable spontaneous electric
polarization. With the fully optimized crystalline structure of the most stable
configuration, the spontaneous polarization is obtained to be 23 $\mu$C/cm$^2$
along the z direction, which originates from the hybridization between the 3d
states of the Fe$^{3+}$ cation and the 2p states of oxygen induced by
Jahn-Teller effect.


title:
Gravitational wave emission by the high braking index pulsar PSR
  J1640-4631

abstract:
  Recently, a braking index for the pulsar PSR J1640-4631 has been measured.
With a braking index of $n = 3.15 \pm 0.03$, this pulsar has the highest
braking index ever measured. As it is well known, a pure magnetic dipole brake
yields $n = 3$, whereas a pure gravitational wave brake yields $n = 5$.
Therefore, each of these mechanisms alone can not account for the braking index
found for PSR J1640-4631. Here we show that such a braking index can be
accounted for if the spindown model combines magnetic dipole and gravitational
wave brakes. Then, we briefly discuss the detectability of this pulsar by aLIGO
and the planned Einstein Telescope. In particular, we show that the amplitude
of the gravitational wave that comes from our model is around a factor four
lower than the amplitude modeled exclusively by gravitational wave energy loss.
Another interesting outcome of our modeling is that we are able to obtain the
ellipticity from the braking index and other pulsar parameters.


title:
BICEP2 / Keck Array VII: Matrix based E/B Separation applied to BICEP2
  and the Keck Array

abstract:
  A linear polarization field on the sphere can be uniquely decomposed into an
E-mode and a B-mode component. These two components are analytically defined in
terms of spin-2 spherical harmonics. Maps that contain filtered modes on a
partial sky can also be decomposed into E-mode and B-mode components. However,
the lack of full sky information prevents orthogonally separating these
components using spherical harmonics. In this paper, we present a technique for
decomposing an incomplete map into E and B-mode components using E and B
eigenmodes of the pixel covariance in the observed map. This method is found to
orthogonally define E and B in the presence of both partial sky coverage and
spatial filtering. This method has been applied to the BICEP2 and the Keck
Array maps and results in reducing E to B leakage from LCDM E-modes to a level
corresponding to a tensor-to-scalar ratio of $r<1\times10^{-4}$.


title:
Connecting the new H.E.S.S. diffuse emission at the Galactic center with
  the Fermi GeV excess: a combination of millisecond pulsars and heavy dark
  matter?

abstract:
  The H.E.S.S. collaboration has reported a high-energy spherically symmetric
diffuse gamma-ray emission in the inner 50 pc of the Milky Way, up to ~ 50 TeV.
Here we propose a leptonic model which provides an alternative to the hadronic
scenario presented by the H.E.S.S. collaboration, and connects the newly
reported TeV emission to the Fermi-LAT Galactic center GeV excess. Our model
relies on a combination of inverse Compton emission from a population of
millisecond pulsars---which can account for the GeV excess---and a supermassive
black hole-induced spike of heavy (~ 60 TeV) dark matter particles annihilating
into electrons with a sub-thermal cross-section. With an up-to-date
interstellar radiation field, as well as a standard magnetic field and
diffusion set-up, our model accounts for the spectral morphology of the
detected emission. Moreover, we show that the dark matter induced emission
reproduces the spatial morphology of the H.E.S.S. signal above ~ 10 TeV, while
we obtain a slightly more extended component from pulsars at lower energies,
which could be used as a prediction for future H.E.S.S. observations.

categories: astro-ph.HE astro-ph.CO astro-ph.GA hep-ph


title: Diphoton Resonance from a Warped Extra Dimension

abstract:
  We argue that extensions of the Standard Model (SM) with a warped extra
dimension, which successfully address the hierarchy and flavor problems of
elementary particle physics, can provide an elegant explanation of the 750 GeV
diphoton excess recently reported by ATLAS and CMS. A gauge-singlet bulk scalar
with ${\cal O}(1)$ couplings to fermions is identified as the new resonance
$S$, and the vector-like Kaluza-Klein excitations of the SM quarks and leptons
mediate its loop-induced couplings to photons and gluons. The electroweak gauge
symmetry almost unambiguously dictates the bulk matter content and hence the
hierarchies of the $S\to \gamma\gamma$, $WW$, $ZZ$, $Z\gamma$, $t\bar t$ and
dijet decay rates. We find that the $S\to Z\gamma$ decay mode is strongly
suppressed, such that $\mbox{Br}(S\to
Z\gamma)/\mbox{Br}(S\to\gamma\gamma)<0.1$. The hierarchy problem for the new
scalar boson is solved in analogy with the Higgs boson by localizing it near
the infrared brane. The infinite sums over the Kaluza-Klein towers of fermion
states are finite and can be calculated in closed form with a remarkably simple
result. Reproducing the observed $pp\to S\to\gamma\gamma$ signal requires
Kaluza-Klein masses in the multi-TeV range, consistent with bounds from flavor
physics and electroweak precision observables.
  Useful side products of our analysis, which can be adapted to almost any
model for the diphoton resonance, are the calculation of the gluon-fusion
production cross section $\sigma(pp\to S)$ at NNLO in QCD, an exact expression
for the inclusive $S\to gg$ decay rate at N$^3$LO, a study of the $S\to t\bar t
h$ three-body decay and a phenomenological analysis of portal couplings
connecting $S$ with the Higgs field.


title:
The effects of short-lived radionuclides and porosity on the early
  thermo-mechanical evolution of planetesimals

abstract:
  The thermal history and internal structure of chondritic planetesimals,
assembled before the giant impact phase of chaotic growth, potentially yield
important implications for the final composition and evolution of terrestrial
planets. These parameters critically depend on the internal balance of heating
versus cooling, which is mostly determined by the presence of short-lived
radionuclides (SLRs), such as aluminum-26 and iron-60, as well as the heat
conductivity of the material. The heating by SLRs depends on their initial
abundances, the formation time of the planetesimal and its size. It has been
argued that the cooling history is determined by the porosity of the granular
material, which undergoes dramatic changes via compaction processes and tends
to decrease with time. In this study we assess the influence of these
parameters on the thermo-mechanical evolution of young planetesimals with both
2D and 3D simulations. Using the code family I2ELVIS/I3ELVIS we have run
numerous 2D and 3D numerical finite-difference fluid dynamic models with
varying planetesimal radius, formation time and initial porosity. Our results
indicate that powdery materials lowered the threshold for melting and
convection in planetesimals, depending on the amount of SLRs present. A subset
of planetesimals retained a powdery surface layer which lowered the thermal
conductivity and hindered cooling. The effect of initial porosity was small,
however, compared to those of planetesimal size and formation time, which
dominated the thermo-mechanical evolution and were the primary factors for the
onset of melting and differentiation. We comment on the implications of this
work concerning the structure and evolution of these planetesimals, as well as
their behavior as possible building blocks of terrestrial planets.


title:
Stability mechanisms of high current transport in iron-chalcogenides
  superconducting films

abstract:
  The improvement in the fabrication techniques of iron-based superconductors
have made these materials real competitors of high temperature superconductors
and MgB$_2$. In particular, iron-chalcogenides have proved to be the most
promising for the realization of high current carrying tapes. But their use on
a large scale cannot be achieved without the understanding of the current
stability mechanisms in these compounds. Indeed, we have recently observed the
presence of flux flow instabilities features in Fe(Se,Te) thin films grown on
CaF$_2$. Here we present the results of current-voltage characterizations at
different temperatures and applied magnetic fields on Fe(Se,Te) microbridges
grown on CaF$_2$. These results will be analyzed from the point of view of the
most validated models with the aim to identify the nature of the flux flow
instabilities features (i.e., thermal or electronic), in order to give a
further advance to the high current carrying capability of iron-chalcogenide
superconductors.


title:
Galaxy Populations in the 26 most massive Galaxy Clusters in the South
  Pole Telescope SZE Survey

abstract:
  We present a study of the optical properties of the 26 most massive galaxy
clusters selected within the SPT-SZ 2500 deg$^2$ survey. This
Sunyaev-Zel'dovich effect selected sample spans a redshift range of 0.10 < z <
1.13. We measure the galaxy radial profile, the luminosity function (LF), and
the halo occupation number (HON) using optical data with a typical depth of
$m^*$ + 2. The stacked radial profiles are consistent with a NFW profile with a
concentration of $2.84^{+0.40}_{-0.37}$ for the red sequence (RS) and
$2.36^{+0.38}_{-0.35}$ for the total population. Stacking the data in multiple
redshift bins shows a hint of redshift evolution in the concentration when both
the total population is used, and when only RS galaxies are used (at
2.1$\sigma$ and 2.8$\sigma$, respectively). The stacked LF shows a faint end
slope $\alpha = -1.06^{+0.04}_{-0.03}$ for the total and $\alpha =
-0.80^{+0.04}_{-0.03}$ for the RS population. The redshift evolution of $m^*$
is found to be consistent with a passively evolving Composite Stellar
Population (CSP) model. By adopting the CSP model predictions, we explore the
redshift evolution of the schechter parameters $\alpha$ and $\phi^*$. We find
$\alpha$ for the total population to be consistent with no evolution
(0.3$\sigma$), while evidence of evolution for the red galaxies is mildly
significant (1.1-2.1$\sigma$). The data show that the density $\phi^*$/E$^2$(z)
decreases with redshift, in tension with the self-similar expectation at a
2.4$\sigma$ level for the total population. The measured HON-mass relation has
a lower normalization than previous studies at low redshift. Finally, our data
support HON redshift evolution at a 2.1$\sigma$ level, with clusters at higher
redshift containing fewer galaxies per unit mass to $m^*$ + 3 than their low-z
counterparts [abridged].


title: Anomalous vacuum energy and stability of a quantum liquid

abstract:
  We show that the vacuum (zero-point) energy of a low-temperature quantum
liquid is a variable property which changes with the state of the system, in
notable contrast to the static vacuum energy in solids commonly considered. We
further show that this energy is inherently anomalous: it decreases with
temperature and gives negative contribution to system's heat capacity. This
effect operates in an equilibrium and macroscopic system, in marked contrast to
small or out-of-equilibrium configurations discussed previously. We find that
the negative contribution is over-compensated by the positive term from the
excitation of longitudinal fluctuations and demonstrate how the overall
positive heat capacity is related to the stability of a condensed phase at the
microscopic level.


title: Scale-Independent Inflation and Hierarchy Generation

abstract:
  We discuss models involving two scalar fields coupled to classical gravity
that satisfy the general criteria: (i) the theory has no mass input parameters,
(ii) classical scale symmetry is broken only through $-\frac{1}{12}\varsigma
\phi^2 R$ couplings where $\varsigma$ departs from the special conformal value
of $1$; (iii) the Planck mass is dynamically generated by the vacuum
expectations values (VEVs) of the scalars (iv) there is a stage of viable
inflation associated with slow roll in the two--scalar potential; (v) the final
vacuum has a small to vanishing cosmological constant and an hierarchically
small ratio of the VEVs and the ratio of the scalar masses to the Planck scale.
This assumes the paradigm of classical scale symmetry as a custodial symmetry
of large hierarchies.


title:
Bimodality of low-redshift circumgalactic O VI in non-equilibrium EAGLE
  zoom simulations

abstract:
  We introduce a series of 20 cosmological hydrodynamical simulations of Lstar
(M_200 =10^11.7 - 10^12.3 Msol) and group-sized (M_200 = 10^12.7 - 10^13.3
Msol) haloes run with the model used for the EAGLE project, which additionally
includes a non-equilibrium ionization and cooling module that follows 136 ions.
The simulations reproduce the observed correlation, revealed by COS-Halos at
z~0.2, between O VI column density at impact parameters b < 150 kpc and the
specific star formation rate (sSFR=SFR/Mstar) of the central galaxy at z~0.2.
We find that the column density of circumgalactic O VI is maximal in the haloes
associated with Lstar galaxies, because their virial temperatures are close to
the temperature at which the ionization fraction of O VI peaks (T~10^5.5 K).
The higher virial temperature of group haloes (> 10^6 K) promotes oxygen to
higher ionization states, suppressing the O VI column density. The observed NO
VI-sSFR correlation therefore does not imply a causal link, but reflects the
changing characteristic ionization state of oxygen as halo mass is increased.
In spite of the mass-dependence of the oxygen ionization state, the most
abundant circumgalactic oxygen ion in both Lstar and group haloes is O VII; O
VI accounts for only 0.1% of the oxygen in group haloes and 0.9-1.3% with Lstar
haloes. Nonetheless, the metals traced by O VI absorbers represent a fossil
record of the feedback history of galaxies over a Hubble time; their
characteristic epoch of ejection corresponds to z > 1 and much of the ejected
metal mass resides beyond the virial radius of galaxies. For both Lstar and
group galaxies, more of the oxygen produced and released by stars resides in
the circumgalactic medium (within twice the virial radius) than in the stars
and ISM of the galaxy.


title:
A Network Approach to Unravel Correlated Ion Pair Dynamics in Protic
  Ionic Liquids. The Case of Triethylammonium Nitrate

abstract:
  The intermolecular interactions in the title compound are investigated using
self-consistent charge density functional based tight binding molecular
dynamics. Emphasis is put on the analysis of correlated motions of ion pairs
using ideas of network theory. At equilibrium such correlations are not very
pronounced on average. However, there exist sizeable local correlations for
cases where two cations share the same anion via two NHO-hydrogen bonds. The
effect of an external perturbation, which artificially introduces a sudden
local heating of an NH-bond, is investigated using nonequilibrium molecular
dynamics. Here, it is found that the average N-H bond vibrational relaxation
time is about 5.3 ~ps. This energy redistribution is rather nonspecific with
respect to the ion pairs and does not lead to long-range correlations spreading
from the initially excited ion pair.


title:
Green$'$s function approach to edge states in transition metal
  dichalcogenides

abstract:
  The semiconducting two-dimensional transition metal dichalcogenides MX$_{2}$
show an abundance of one-dimensional metallic edges and grain boundaries.
Standard techniques for calculating edge states typically model nanoribbons,
and require the use of supercells. In this paper we formulate a Green$'$s
function technique for calculating edge states of (semi-)infinite
two-dimensional systems with a single well-defined edge or grain boundary. We
express Green$'$s functions in terms of Bloch matrices, constructed from the
solutions of a quadratic eigenvalue equation. The technique can be applied to
any localized basis representation of the Hamiltonian. Here we use it to
calculate edge states of MX$_{2}$ monolayers by means of tight-binding models.
Besides the basic zigzag and armchair edges, we study edges with a more general
orientation, structurally modifed edges, and grain boundaries. A simple
three-band model captures an important part of the edge electronic structures.
An eleven-band model comprising all valence orbitals of the M and X atoms, is
required to obtain all edge states with energies in the MX$_{2}$ band gap. Here
states of odd symmetry with respect to a mirror plane through the layer of M
atoms have a dangling-bond character, and tend to pin the Fermi level.


title: SO(d,1)-invariant Yang-Baxter operators and the dS/CFT correspondence

abstract:
  We propose a model for the dS/CFT correspondence. The model is constructed in
terms of a "Yang-Baxter operator" $R$ for unitary representations of the
deSitter group $SO(d,1)$. This $R$-operator is shown to satisfy the Yang-Baxter
equation, unitarity, as well as certain analyticity relations, including in
particular a crossing symmetry. With the aid of this operator we construct: a)
A chiral (light-ray) conformal quantum field theory whose internal degrees of
freedom transform under the given unitary representation of $SO(d,1)$. By
analogy with the $O(N)$ non-linear sigma model, this chiral CFT can be viewed
as propagating in a deSitter spacetime. b) A (non-unitary) Euclidean conformal
quantum field theory on ${\mathbb R}^{d-1}$, where $SO(d,1)$ now acts by
conformal transformations in (Euclidean) spacetime. These two theories can be
viewed as dual to each other if we interpret ${\mathbb R}^{d-1}$ as conformal
infinity of deSitter spacetime. Our constructions use semi-local generator
fields defined in terms of $R$ and abstract methods from operator algebras.


title:
Deflation as a Method of Variance Reduction for Estimating the Trace of
  a Matrix Inverse

abstract:
  Many fields require computing the trace of the inverse of a large, sparse
matrix. The typical method used for such computations is the Hutchinson method
which is a Monte Carlo (MC) averaging over matrix quadratures. To improve its
convergence, several variance reductions techniques have been proposed. In this
paper, we study the effects of deflating the near null singular value space. We
make two main contributions.
  First, we analyze the variance of the Hutchinson method as a function of the
deflated singular values and vectors. Although this provides good intuition in
general, by assuming additionally that the singular vectors are random unitary
matrices, we arrive at concise formulas for the deflated variance that include
only the variance and mean of the singular values. We make the remarkable
observation that deflation may increase variance for Hermitian matrices but not
for non-Hermitian ones. This is a rare, if not unique, property where
non-Hermitian matrices outperform Hermitian ones. The theory can be used as a
model for predicting the benefits of deflation.
  Second, we use deflation in the context of a large scale application of
"disconnected diagrams" in Lattice QCD. On lattices, Hierarchical Probing (HP)
has previously provided an order of magnitude of variance reduction over MC by
removing "error" from neighboring nodes of increasing distance in the lattice.
Although deflation used directly on MC yields a limited improvement of 30% in
our problem, when combined with HP they reduce variance by a factor of over 60
compared to MC. For this, we pre-computated 1000 smallest singular values of an
ill-conditioned matrix of size 25 million. Using PRIMME and a domain-specific
Algebraic Multigrid preconditioner, we perform one of the largest eigenvalue
computations in Lattice QCD at a fraction of the cost of our trace computation.


title:
Breadth versus depth: Interactions that stabilize particle assemblies to
  changes in density or temperature

abstract:
  We use inverse methods of statistical mechanics to explore trade-offs
associated with designing interactions to stabilize self-assembled structures
against changes in density or temperature. Specifically, we find
isotropic,convex-repulsive pair potentials that maximize the density range for
which a two-dimensional square lattice is the stable ground state subject to a
constraint on the chemical potential advantage it exhibits over competing
structures (i.e., 'depth' of the associated minimum on the chemical potential
hypersurface). We formulate the design problem as a non-linear program, which
we solve numerically. This allows us to efficiently find optimized interactions
for a wide range of possible chemical potential constraints. We find that
assemblies designed to exhibit a large chemical potential advantage at a
specified density have a smaller overall range of densities for which they are
stable. This trend can be understood by considering the separation-dependent
features of the pair potential and its gradient required to enhance the
stability of the target structure relative to competitors. Using molecular
dynamics simulations, we further show that potentials designed with larger
chemical potential advantages exhibit higher melting temperatures.


title: The LOFAR Solar Imaging Pipeline and the LOFAR Solar Data Center

abstract:
  LOFAR is a new and sensitive radio interferometer that can be used for
dynamic high-resolution imaging spectroscopy at low radio frequencies from 10
to 90 and 110 to 250 MHz. Here we describe its usage for observations of the
Sun and in particular of solar radio bursts. We also describe the processing,
archiving and accessing of solar LOFAR data, which is accomplished via the
LOFAR Solar Imaging Pipeline and the LOFAR Solar Data Center.


title: Flat line bundles and the Cappell-Miller torsion in Arakelov geometry

abstract:
  In this paper, we extend Deligne's functorial Riemann-Roch isomorphism for
hermitian holomorphic line bundles on Riemann surfaces to the case of flat, not
necessarily unitary connections. The Quillen metric and star-product of
Gillet-Soule are replaced with complex valued logarithms. On the determinant of
cohomology side, the idea goes back to Fay's holomorphic extension of
determinants of Dolbeault laplacians, and it is shown here to be equivalent to
the holomorphic Cappell-Miller torsion. On the Deligne pairing side, the
logarithm is a refinement of the intersection connections considered in
previous work. The construction naturally leads to an Arakelov theory for flat
line bundles on arithmetic surfaces and produces arithmetic intersection
numbers valued in ${\mathbb C}/\pi i {\mathbb Z}$. In this context we prove an
arithmetic Riemann-Roch theorem. This realizes a program proposed by
Cappell-Miller to show that the holomorphic torsion exhibits properties similar
to those of the Quillen metric proved by Bismut, Gillet and Soule. Finally, we
give examples that clarify the kind of invariants that the formalism captures;
namely, periods of differential forms.


title:
The VIMOS Ultra Deep Survey: Lyman Alpha Emission and Stellar
  Populations of Star-Forming Galaxies at 2<z<6

abstract:
  The extensive ground-based spectroscopy campaign from the VIMOS Ultra-Deep
Survey (VUDS), and the deep multi-wavelength photometry in three very well
observed extragalactic fields (ECDFS, COSMOS, VVDS), allow us to investigate
physical properties of a large sample (~4000 galaxies) of spectroscopically
confirmed faint (i_{AB}<~25 mag) star-forming galaxies, with and without Lyman
alpha in emission, at z~2-6. The fraction of Lyman alpha emitters (LAEs;
equivalent width (EW)=>20A) increases from ~10% at z~2 to ~40% at z~5-6, which
is consistent with previous studies that employ higher Lyman alpha EW cut. This
increase in the LAE fraction could be, in part, due to a decrease in the dust
content of galaxies as redshift increases. When we compare best-fit SED
estimated stellar parameters for LAEs and non-LAEs, we find that E(B-V) is
smaller for LAEs at all redshifts and the difference in the median E(B-V)
between LAEs and non-LAEs increases as redshift increases, from 0.05 at z~2 to
0.1 at z~3.5 to 0.2 at z~5-6. For the luminosities probed here (~L*), we find
that star formation rates (SFRs) and stellar masses of galaxies, with and
without Lyman alpha in emission, show small differences such that, LAEs have
lower SFRs and stellar masses compared to non-LAEs. This result could be a
direct consequence of the sample selection. Our sample of LAEs are selected
based on their continuum magnitudes and they probe higher continuum
luminosities compared to narrow-band/emission line selected LAEs. Based on our
results, it is important to note that all LAEs are not universally similar and
their properties are strongly dependent on the sample selection, and/or
continuum luminosities.


title:
A class of spherical, truncated, anisotropic models for application to
  globular clusters

abstract:
  Recently, a class of non-truncated radially-anisotropic models (the so-called
$f^{(\nu)}$-models), originally constructed in the context of violent
relaxation and modeling of elliptical galaxies, has been found to possess
interesting qualities in relation to observed and simulated globular clusters.
In view of new applications to globular clusters, we improve this class of
models along two directions. To make them more suitable for the description of
small stellar systems hosted by galaxies, we introduce a 'tidal' truncation (by
means of a procedure that guarantees full continuity of the distribution
function). The new $f_T^{(\nu)}$-models are shown to provide a better fit to
the observed photometric and spectroscopic profiles for a sample of 13 globular
clusters studied earlier by means of non-truncated models; interestingly, the
best-fit models also perform better with respect to the radial-orbit
instability. Then we design a flexible but simple two-component family of
truncated models, to study the separate issues of mass segregation and of
multiple populations. We do not aim at a fully realistic description of
globular clusters, to compete with the description currently obtained by means
of dedicated simulations. The goal here is to try to identify the simplest
models, that is, those with the smallest number of free parameters, but still
able to provide a reasonable description for clusters that are evidently beyond
the reach of one-component models: with this tool we aim at identifying the key
factors that characterize mass segregation or the presence of multiple
populations. To reduce the relevant parameter space, we formulate a few
physical arguments (based on recent observations and simulations). A first
application to two well-studied globular clusters is briefly described and
discussed.


title: Effective Field Theory of Dark Matter: a Global Analysis

abstract:
  We present global fits of an effective field theory description of real, and
complex scalar dark matter candidates. We simultaneously take into account all
possible dimension 6 operators consisting of dark matter bilinears and gauge
invariant combinations of quark and gluon fields. We derive constraints on the
free model parameters for both the real (five parameters) and complex (seven)
scalar dark matter models obtained by combining Planck data on the cosmic
microwave background, direct detection limits from LUX, and indirect detection
limits from the Fermi Large Area Telescope. We find that for real scalars
indirect dark matter searches disfavour a dark matter particle mass below 100
GeV. For the complex scalar dark matter particle current data have a limited
impact due to the presence of operators that lead to p-wave annihilation, and
also do not contribute to the spin-independent scattering cross- section.
Although current data are not informative enough to strongly constrain the
theory parameter space, we demonstrate the power of our formalism to
reconstruct the theoretical parameters compatible with an actual dark matter
detection, by assuming that the excess of gamma rays observed by the Fermi
Large Area Telescope towards the Galactic centre is entirely due to dark matter
annihilations. Please note that the excess can very well be due to
astrophysical sources such as millisecond pulsars. We find that scalar dark
matter interacting via effective field theory operators can in principle
explain the Galactic centre excess, but that such interpretation is in strong
tension with the non-detection of gamma rays from dwarf galaxies in the real
scalar case. In the complex scalar case there is enough freedom to relieve the
tension.


title: Diffeomorphism groups of compact convex sets

abstract:
  For a compact convex subset K with non-empty interior in a finite-dimensional
vector space, let G be the group of all smooth diffeomorphisms of K which fix
the boundary of K pointwise. We show that G is a C^0-regular
infinite-dimensional Lie group. As a byproduct, we obtain results concerning
solutions to ordinary differential equations on compact convex sets.


title:
Star-forming galaxies versus low- and high-excitation radio AGN in the
  VLA-COSMOS 3GHz Large Project

abstract:
  We study the composition of the faint radio population selected from the
VLA-COSMOS 3GHz Large Project, a radio continuum survey performed at 10 cm
wavelength. The survey covers the full 2 square degree COSMOS field with mean
$rms\sim2.3$ $\mu$Jy/beam, cataloging 10,899 source components above $5\times
rms$. By combining these radio data with UltraVISTA, optical, near-infrared,
and Spitzer/IRAC mid-infrared data, as well as X-ray data from the Chandra
Legacy, and Chandra COSMOS surveys, we gain insight into the emission
mechanisms within our radio sources out to redshifts of $z\sim5$. From these
emission characteristics we classify our souces as star forming galaxies or
AGN. Using their multi-wavelength properties we further separate the AGN into
sub-samples dominated by radiatively efficient and inefficient AGN, often
referred to as high- and low-excitation emission line AGN. We compare our
method with other results based on fitting of the sources' spectral energy
distributions using both galaxy and AGN spectral models, and those based on the
infrared-radio correlation. We study the fractional contributions of these
sub-populations down to radio flux levels of $\sim$10 $\mu$Jy. We find that at
3 GHz flux densities above $\sim$400 $\mu$Jy quiescent, red galaxies,
consistent with the low-excitation radio AGN class constitute the dominant
fraction. Below densities of $\sim$200 $\mu$Jy star-forming galaxies begin to
constitute the largest fraction, followed by the low-excitation, and X-ray- and
IR-identified high-excitation radio AGN.


title:
Retrieval of Precise Radial Velocities from Near-Infrared High
  Resolution Spectra of Low Mass Stars

abstract:
  Given that low-mass stars have intrinsically low luminosities at optical
wavelengths and a propensity for stellar activity, it is advantageous for
radial velocity (RV) surveys of these objects to use near-infrared (NIR)
wavelengths. In this work we describe and test a novel RV extraction pipeline
dedicated to retrieving RVs from low mass stars using NIR spectra taken by the
CSHELL spectrograph at the NASA Infrared Telescope Facility, where a methane
isotopologue gas cell is used for wavelength calibration. The pipeline
minimizes the residuals between the observations and a spectral model composed
of templates for the target star, the gas cell, and atmospheric telluric
absorption; models of the line spread function, continuum curvature, and
sinusoidal fringing; and a parameterization of the wavelength solution. The
stellar template is derived iteratively from the science observations
themselves without a need for separate observations dedicated to retrieving it.
Despite limitations from CSHELL's narrow wavelength range and instrumental
systematics, we are able to (1) obtain an RV precision of 35 m/s for the RV
standard star GJ 15 A over a time baseline of 817 days, reaching the photon
noise limit for our attained SNR, (2) achieve ~3 m/s RV precision for the M
giant SV Peg over a baseline of several days and confirm its long-term RV trend
due to stellar pulsations, as well as obtain nightly noise floors of ~2 - 6
m/s, and (3) show that our data are consistent with the known masses, periods,
and orbital eccentricities of the two most massive planets orbiting GJ 876.
Future applications of our pipeline to RV surveys using the next generation of
NIR spectrographs, such as iSHELL, will enable the potential detection of
Super-Earths and Mini-Neptunes in the habitable zones of M dwarfs.


title: A High-Precision NIR Survey for RV Variable Low-Mass Stars

abstract:
  We present the results of a precise near-infrared (NIR) radial velocity (RV)
survey of 32 low-mass stars with spectral types K2-M4 using CSHELL at the NASA
IRTF in the $K$-band with an isotopologue methane gas cell to achieve
wavelength calibration and a novel iterative RV extraction method. We surveyed
14 members of young ($\approx$ 25-150 Myr) moving groups, the young field star
$\varepsilon$ Eridani as well as 18 nearby ($<$ 25 pc) low-mass stars and
achieved typical single-measurement precisions of 8-15 m s$^{-1}$ with a
long-term stability of 15-50 m s$^{-1}$. We obtain the best NIR RV constraints
to date on 27 targets in our sample, 19 of which were never followed by
high-precision RV surveys. Our results indicate that very active stars can
display long-term RV variations as low as $\sim$ 25-50 m s$^{-1}$ at $\approx$
2.3125 $\mu$m, thus constraining the effect of jitter at these wavelengths. We
provide the first multi-wavelength confirmation of GJ 876 bc and independently
retrieve orbital parameters consistent with previous studies. We recovered RV
variability for HD 160934 AB and GJ 725 AB that are consistent with their known
binary orbits, and nine other targets are candidate RV variables with a
statistical significance of 3-5$\sigma$. Our method combined with the new
iSHELL spectrograph will yield long-term RV precisions of $\lesssim$ 5 m
s$^{-1}$ in the NIR, which will allow the detection of Super-Earths near the
habitable zone of mid-M dwarfs.


title: Precise Near-Infrared Radial Velocities

abstract:
  We present the results of two 2.3 micron near-infrared radial velocity
surveys to detect exoplanets around 36 nearby and young M dwarfs. We use the
CSHELL spectrograph (R ~46,000) at the NASA InfraRed Telescope Facility,
combined with an isotopic methane absorption gas cell for common optical path
relative wavelength calibration. We have developed a sophisticated RV forward
modeling code that accounts for fringing and other instrumental artifacts
present in the spectra. With a spectral grasp of only 5 nm, we are able to
reach long-term radial velocity dispersions of ~20-30 m/s on our survey
targets.


title:
Photo-reverberation Mapping of a Protoplanetary Accretion Disk around a
  T Tauri Star

abstract:
  Theoretical models and spectroscopic observations of newborn stars suggest
that protoplantary disks have an inner "wall" at a distance set by the disk
interaction with the star. Around T Tauri stars, the size of this disk hole is
expected to be on a 0.1-AU scale that is unresolved by current adaptive optics
imaging, though some model-dependent constraints have been obtained by
near-infrared interferometry. Here we report the first measurement of the inner
disk wall around a solar-mass young stellar object, YLW 16B in the {\rho}
Ophiuchi star-forming region, by detecting the light travel time of the
variable radiation from the stellar surface to the disk. Consistent time lags
were detected on two nights, when the time series in H (1.6 {\mu}m) and K (2.2
{\mu}m) bands were synchronized while the 4.5 {\mu}m emission lagged by 74.5
+/- 3.2 seconds. Considering the nearly edge-on geometry of the disk, the inner
rim should be 0.084 AU from the protostar on average, with an error of order
0.01 AU. This size is likely larger than the range of magnetospheric
truncations, and consistent with an optically and geometrically thick disk
front at the dust sublimation radius at ~1500 K. The widths of the
cross-correlation functions between the data in different wavebands place
possible new constraints on the geometry of the disk.


title:
Application of the Trend Filtering Algorithm for Photometric Time Series
  Data

abstract:
  Detecting transient light curves (e.g., transiting planets) requires high
precision data, and thus it is important to effectively filter systematic
trends affecting ground based wide field surveys. We apply an implementation of
the Trend Filtering Algorithm (TFA) (Kovacs et al. 2005) to the 2MASS
calibration catalog and select Palomar Transient Factory (PTF) photometric time
series data. TFA is successful at reducing the overall dispersion of light
curves, however it may over filter intrinsic variables and increase
"instantaneous" dispersion when a template set is not judiciously chosen. In an
attempt to rectify these issues we modify the original literature TFA by
including measurement uncertainties in its computation, including ancillary
data correlated with noise, and algorithmically selecting a template set using
clustering algorithms as suggested by various authors. This approach may be
particularly useful for appropriately accounting for variable photometric
precision surveys and/or combined data-sets. In summary, our contributions are
to provide a MATLAB software implementation of TFA and a number of
modifications tested on synthetics and real data, summarize the performance of
TFA and various modifications on real ground based data sets (2MASS and PTF),
and assess the efficacy of TFA and modifications using synthetic light curve
tests consisting of transiting and sinusoidal variables. While the transiting
variables test indicates that these modifications confer no advantage to
transit detection, the sinusoidal variables test indicates potential
improvements in detection accuracy.


title: A Message Passing Algorithm for the Problem of Path Packing in Graphs

abstract:
  We consider the problem of packing node-disjoint directed paths in a directed
graph. We consider a variant of this problem where each path starts within a
fixed subset of root nodes, subject to a given bound on the length of paths.
This problem is motivated by the so-called kidney exchange problem, but has
potential other applications and is interesting in its own right.
  We propose a new algorithm for this problem based on the message
passing/belief propagation technique. A priori this problem does not have an
associated graphical model, so in order to apply a belief propagation algorithm
we provide a novel representation of the problem as a graphical model. Standard
belief propagation on this model has poor scaling behavior, so we provide an
efficient implementation that significantly decreases the complexity. We
provide numerical results comparing the performance of our algorithm on both
artificially created graphs and real world networks to several alternative
algorithms, including algorithms based on integer programming (IP) techniques.
These comparisons show that our algorithm scales better to large instances than
IP-based algorithms and often finds better solutions than a simple algorithm
that greedily selects the longest path from each root node. In some cases it
also finds better solutions than the ones found by IP-based algorithms even
when the latter are allowed to run significantly longer than our algorithm.


title:
Large deviation function for the number of eigenvalues of sparse random
  graphs inside an interval

abstract:
  We present a general method to obtain the exact rate function
$\Psi_{[a,b]}(k)$ controlling the large deviation probability
$\text{Prob}[\mathcal{I}_N[a,b]=kN] \asymp e^{-N\Psi_{[a,b]}(k)}$ that a $N
\times N$ sparse random matrix has $\mathcal{I}_N[a,b]=kN$ eigenvalues inside
the interval $[a,b]$. The method is applied to study the eigenvalue statistics
in two distinct examples: (i) the shifted index number of eigenvalues for an
ensemble of Erd\"os-R\'enyi graphs and (ii) the number of eigenvalues within a
bounded region of the spectrum for the Anderson model on regular random graphs.
A salient feature of the rate function in both cases is that, unlike
rotationally invariant random matrices, it is asymmetric with respect to its
minimum. The asymmetric character depends on the disorder in a way that is
compatible with the distinct eigenvalue statistics corresponding to localized
and delocalized eigenstates. The results also show that the number variance
$\sigma_{N}^{2}$ for the Anderson model on a regular graph scales as
$\sigma_{N}^{2} \propto N$ ($N \gg 1$) for any nonzero disorder, which is
consistent with the absence of level-repulsion in the extended phase. Our
theoretical findings are thoroughly compared to numerical diagonalization in
both cases, showing a reasonable good agreement.


title: Origin of dissipative Fermi arc transport in Weyl semimetals

abstract:
  By making use of a low-energy effective model of Weyl semimetals, we show
that the Fermi arc transport is dissipative. The origin of the dissipation is
the scattering of the surface Fermi arc states into the bulk of the semimetal.
It is noticeable that corresponding scattering rate is nonzero and can be
estimated even in a perturbative theory, although in general the reliable
calculations of transport properties necessitate a nonperturbative approach.
Nondecoupling of the surface and bulk sectors in the low-energy theory of Weyl
semimetals invalidates the usual argument of a nondissipative transport due to
one-dimensional arc states. This property of Weyl semimetals is in drastic
contrast to that of topological insulators, where the decoupling is protected
by a gap in the bulk. Within the framework of the linear response theory, we
obtain an approximate result for the conductivity due to the Fermi arc states
and analyze its dependence on chemical potential, temperature, and other
parameters of the model.


title:
A note of the convergence of the Fisher-KPP front centred around its
  $\alpha$-level

abstract:
  We consider the solution $u(x,t)$ of the Fisher-KPP equation $\partial_t
u=\partial_x^2u+u-u^2$ centred around its $\alpha$-level $\mu_t^{(\alpha)}$
defined as $u(\mu_t^{(\alpha)},t)=\alpha$. It is well known that for an initial
datum that decreases fast enough, then $u(\mu_t^{(\alpha)}+x,t)$ converges as
$t\to\infty$ to the critical travelling wave. We study in this paper the speed
of this convergence and the asymptotic expansion of $\mu_t^{(\alpha)}$ for
large~$t$. It is known from Bramson that for initial conditions that decay fast
enough, one has $\mu_t^{(\alpha)}=2t-(3/2)\ln t+\text{Cste}+o(1)$. Work is
under way \cite{nrr} to show that the $o(1)$ in the expansion is in fact a
$k^{(\alpha)}/\sqrt t+\mathcal O(t^{\epsilon-1})$ for any $\epsilon>0$ for some
$k^{(\alpha)}$, where it is not clear at this point whether $k^{(\alpha)}$
depends or not on $\alpha$. We show that, unless the time derivative of
$\mu_t^{(\alpha)}$ has a very unexpected behaviour at infinity, the coefficient
$k^{(\alpha)}$ does not, in fact, depend on $\alpha$.
  We also conjecture that, for an initial condition that decays fast enough,
one has in fact $\mu_t^{(\alpha)}=2t-(3/2)\ln t+\text{Cste}-(3\sqrt\pi)/\sqrt
t+g (\ln t)/t +o (1/t)$ for some constant~$g$ which does not depend on
$\alpha$.


title:
Polynomial Time Relatively Computable Triangular Arrays in a Multinomial
  Setting

abstract:
  We extend the methods and results of [arXiv 1603.04896] to the setting of
multinomial distributions satisfying certain properties. These include all the
multinomial distributions arising from the direct proof of the Central Limit
Theorem given in [arXiv: 1507.00357], which, by results of that paper,
constitutes essentially full generality for the situations in which the Central
Limit Theorem holds.


title:
Studying the evolution of galaxies in compact groups over the past 3 Gyr
  - II. The importance of environment in the suppression of star formation

abstract:
  We present an in depth study on the evolution of galaxy properties in compact
groups over the past 3 Gyr. We are using the largest multi-wavelength sample
to-date, comprised 1770 groups (containing 7417 galaxies), in the redshift
range of 0.01<z<0.23. To derive the physical properties of the galaxies we rely
on ultraviolet (UV)-to-infrared spectral energy distribution modeling, using
CIGALE. Our results suggest that during the 3 Gyr period covered by our sample,
the star formation activity of galaxies in our groups has been substantially
reduced (3-10 times). Moreover, their star formation histories as well as their
UV-optical and mid-infrared colors are significantly different from those of
field and cluster galaxies, indicating that compact group galaxies spend more
time transitioning through the green valley. The morphological transformation
from late-type spirals into early-type galaxies occurs in the mid-infrared
transition zone rather than in the UV-optical green valley. We find evidence of
shocks in the emission line ratios and gas velocity dispersions of the
late-type galaxies located below the star forming main sequence. Our results
suggest that in addition to gas stripping, turbulence and shocks might play an
important role in suppressing the star formation in compact group galaxies.


title: What Happens in a Measurement?

abstract:
  It is assumed that in a measurement the system under study interacts with a
macroscopic measuring apparatus, in such a way that the density matrix of the
measured system evolves according to the Lindblad equation. Under an assumption
of non-decreasing von Neumann entropy, conditions on the operators appearing in
this equation are given that are necessary and sufficient for the late-time
limit of the density matrix to take the form appropriate for a measurement.
Where these conditions are satisfied, the Lindblad equation can be solved
explicitly. The probabilities appearing in the late-time limit of this general
solution are found to agree with the Born rule, and are independent of the
details of the operators in the Lindblad equation.


title: Readability-based Sentence Ranking for Evaluating Text Simplification

abstract:
  We propose a new method for evaluating the readability of simplified
sentences through pair-wise ranking. The validity of the method is established
through in-corpus and cross-corpus evaluation experiments. The approach
correctly identifies the ranking of simplified and unsimplified sentences in
terms of their reading level with an accuracy of over 80%, significantly
outperforming previous results. To gain qualitative insights into the nature of
simplification at the sentence level, we studied the impact of specific
linguistic features. We empirically confirm that both word-level and syntactic
features play a role in comparing the degree of simplification of authentic
data. To carry out this research, we created a new sentence-aligned corpus from
professionally simplified news articles. The new corpus resource enriches the
empirical basis of sentence-level simplification research, which so far relied
on a single resource. Most importantly, it facilitates cross-corpus evaluation
for simplification, a key step towards generalizable results.


title:
Frontier Fields Clusters: Deep Chandra Observations of the Complex
  Merger MACS J1149.6+2223

abstract:
  The HST Frontier Fields cluster MACS J1149.6+2223 is one of the most complex
merging clusters, believed to consist of four dark matter halos. We present
results from deep (365 ks) Chandra observations of the cluster, which reveal
the most distant cold front (z=0.544) discovered to date. In the cluster
outskirts, we also detect hints of a surface brightness edge that could be the
bow shock preceding the cold front. The substructure analysis of the cluster
identified several components with large relative radial velocities, thus
indicating that at least some collisions occur almost along the line of sight.
The inclination of the mergers with respect to the plane of the sky poses
significant observational challenges at X-ray wavelengths. MACS J1149.6+2223
possibly hosts a steep-spectrum radio halo. If the steepness of the radio halo
is confirmed, then the radio spectrum, combined with the relatively regular ICM
morphology, could indicate that MACS J1149.6+2223 is an old merging cluster.


title: Random Matrix Theory and Quantum Chromodynamics

abstract:
  These notes are based on the lectures delivered at the Les Houches Summer
School in July 2015. They are addressed at a mixed audience of physicists and
mathematicians with some basic working knowledge of random matrix theory. The
first part is devoted to the solution of the chiral Gaussian Unitary Ensemble
in the presence of characteristic polynomials, using orthogonal polynomial
techniques. This includes all eigenvalue density correlation functions,
smallest eigenvalue distributions and their microscopic limit at the origin.
These quantities are relevant for the description of the Dirac operator
spectrum in Quantum Chromodynamics with three colours in four Euclidean
space-time dimensions. In the second part these two theories are related based
on symmetries, and the random matrix approximation is explained. In the last
part recent developments are covered including the effect of finite chemical
potential and finite space-time lattice spacing, and their corresponding
orthogonal polynomials. We also give some open random matrix problems.


title:
Enabling Correct Interest Forwarding and Retransmissions in a Content
  Centric Network

abstract:
  We show that the mechanisms used in the name data networking (NDN) and the
original content centric networking (CCN) architectures may not detect Interest
loops, even if the network in which they operate is static and no faults occur.
Furthermore, we show that no correct Interest forwarding strategy can be
defined that allows Interest aggregation and attempts to detect Interest
looping by identifying Interests uniquely. We introduce SIFAH (Strategy for
Interest Forwarding and Aggregation with Hop-Counts), the first Interest
forwarding strategy shown to be correct under any operational conditions of a
content centric network. SIFAH operates by having forwarding information bases
(FIBs) store the next hops and number of hops to named content, and by having
each Interest state the name of the requested content and the hop count from
the router forwarding an Interest to the content. We present the results of
simulation experiments using the ndnSIM simulator comparing CCN and NDN with
SIFAH. The results of these experiments illustrate the negative impact of
undetected Interest looping when Interests are aggregated in CCN and NDN, and
the performance advantages of using SIFAH.


title: Large Cayley digraphs and bipartite Cayley digraphs of odd diameters

abstract:
  Let $C_{d,k}$ be the largest number of vertices in a Cayley digraph of degree
$d$ and diameter $k$, and let $BC_{d,k}$ be the largest order of a bipartite
Cayley digraph for given $d$ and $k$. For every degree $d\geq2$ and for every
odd $k$ we construct Cayley digraphs of order
$2k\left(\lfloor\frac{d}{2}\rfloor\right)^k$ and diameter at most $k$, where
$k\ge 3$, and bipartite Cayley digraphs of order
$2(k-1)\left(\lfloor\frac{d}{2}\rfloor\right)^{k-1}$ and diameter at most $k$,
where $k\ge 5$. These constructions yield the bounds $C_{d,k} \ge
2k\left(\lfloor\frac{d}{2}\rfloor\right)^k$ for odd $k\ge 3$ and $d\ge
\frac{3^{k}}{2k}+1$, and $BC_{d,k} \ge
2(k-1)\left(\lfloor\frac{d}{2}\rfloor\right)^{k-1}$ for odd $k\ge 5$ and $d\ge
\frac{3^{k-1}}{k-1}+1$. Our constructions give the best currently known bounds
on the orders of large Cayley digraphs and bipartite Cayley digraphs of given
degree and odd diameter $k\ge 5$. In our proofs we use new techniques based on
properties of group automorphisms of direct products of abelian groups.


title:
Similarity of ensembles of trajectories of reversible and irreversible
  growth processes

abstract:
  Models of bacterial growth tend to be `irreversible', allowing for the number
of bacteria in a colony to increase but not to decrease. By contrast, models of
molecular self-assembly are usually `reversible', allowing for addition and
removal of particles to a structure. Such processes differ in a fundamental way
because only reversible processes possess an equilibrium. Here we show at
mean-field level that dynamic trajectories of reversible and irreversible
growth processes are similar in that both feel the influence of attractors, at
which growth proceeds without limit but the intensive properties of the system
are invariant. Attractors of both processes undergo nonequilibrium phase
transitions as model parameters are varied, suggesting a unified way of
describing reversible and irreversible growth. We also establish a connection
at mean-field level between an irreversible model of growth (the magnetic Eden
model) and the equilibrium Ising model, supporting the findings made by other
authors using numerical simulations.


title:
A Comprehensive Performance Evaluation of Deformable Face Tracking
  "In-the-Wild"

abstract:
  Recently, technologies such as face detection, facial landmark localisation
and face recognition and verification have matured enough to provide effective
and efficient solutions for imagery captured under arbitrary conditions
(referred to as "in-the-wild"). This is partially attributed to the fact that
comprehensive "in-the-wild" benchmarks have been developed for face detection,
landmark localisation and recognition/verification. A very important technology
that has not been thoroughly evaluated yet is deformable face tracking
"in-the-wild". Until now, the performance has mainly been assessed
qualitatively by visually assessing the result of a deformable face tracking
technology on short videos. In this paper, we perform the first, to the best of
our knowledge, thorough evaluation of state-of-the-art deformable face tracking
pipelines using the recently introduced 300VW benchmark. We evaluate many
different architectures focusing mainly on the task of on-line deformable face
tracking. In particular, we compare the following general strategies: (a)
generic face detection plus generic facial landmark localisation, (b) generic
model free tracking plus generic facial landmark localisation, as well as (c)
hybrid approaches using state-of-the-art face detection, model free tracking
and facial landmark localisation technologies. Our evaluation reveals future
avenues for further research on the topic.


title:
Updated Study of a Precision Measurement of the W Mass from a Threshold
  Scan Using Polarized $\rm{e}^-$ and $\rm{e}^+$ at ILC

abstract:
  An updated study of measuring the W mass from a polarized threshold scan at
ILC is presented with an emphasis on evaluating scan strategies that control
experimental systematics. Highly longitudinally polarized beams of electrons
and positrons such as are feasible at ILC offer significant advantages in terms
of statistical power and in-situ control of background. Eventual experimental
precision of around 2 MeV can be envisaged from this technique. Further work on
both the accelerator design and theoretical uncertainties will likely be needed
to take full advantage of this opportunity.


title: Automatic Theorem Proving in Walnut

abstract:
  Walnut is a software package that implements a mechanical decision procedure
for deciding certain combinatorial properties of some special words referred to
as automatic words or automatic sequences. Walnut is written in Java and is
open source. It is licensed under GNU General Public License.


title: Philosophical Solution to P=?NP: P is Equal to NP

abstract:
  The P=?NP problem is philosophically solved by showing P is equal to NP in
the random access with unit multiply (MRAM) model. It is shown that the MRAM
model empirically best models computation hardness. The P=?NP problem is shown
to be a scientific rather than a mathematical problem. The assumptions involved
in the current definition of the P?=NP problem as a problem involving non
deterministic Turing Machines (NDTMs) from axiomatic automata theory are
criticized. The problem is also shown to be neither a problem in pure nor
applied mathematics. The details of The MRAM model and the well known Hartmanis
and Simon construction that shows how to code and simulate NDTMs on MRAM
machines is described. Since the computation power of MRAMs is the same as
NDTMs, P is equal to NP. The paper shows that the justification for the NDTM
P?=NP problem using a letter from Kurt Godel to John Von Neumann is incorrect
by showing Von Neumann explicitly rejected automata models of computation
hardness and used his computer architecture for modeling computation that is
exactly the MRAM model. The paper argues that Deolalikar's scientific solution
showing P not equal to NP if assumptions from statistical physics are used,
needs to be revisited.


title:
Scaling-up quantum heat engines efficiently via shortcuts to
  adiabaticity

abstract:
  The finite-time operation of a quantum heat engine that uses a single
particle as a working medium generally increases the output power at the
expense of inducing friction that lowers the cycle efficiency. We propose to
scale up a quantum heat engine utilizing a many-particle working medium in
combination with the use of shortcuts to adiabaticity to boost the nonadiabatic
performance by eliminating quantum friction and reducing the cycle time. To
this end, we first analyze the finite-time thermodynamics of a quantum Otto
cycle implemented with a quantum fluid confined in a time-dependent harmonic
trap. We show that nonadiabatic effects can be controlled and tailored to match
the adiabatic performance using a variety of shortcuts to adiabaticity. As a
result, the nonadiabatic dynamics of the scaled-up many-particle quantum heat
engine exhibits no friction and the cycle can be run at maximum efficiency with
a tunable output power. We demonstrate our results with a working medium
consisting of particles with inverse-square pairwise interactions, that
includes noninteracting and hard-core bosons as limiting cases.

categories: quant-ph math-ph math.MP physics.atom-ph


title:
Algebraic Properties of Quandle Extensions and Values of Cocycle Knot
  Invariants

abstract:
  Quandle 2-cocycles define invariants of classical and virtual knots, and
extensions of quandles. We show that the quandle 2-cocycle invariant with
respect to a non-trivial $2$-cocycle is constant, or takes some other
restricted form, for classical knots when the corresponding extensions satisfy
certain algebraic conditions. In particular, if an abelian extension is a
conjugation quandle, then the corresponding cocycle invariant is constant.
Specific examples are presented from the list of connected quandles of order
less than 48. Relations among various quandle epimorphisms involved are also
examined.


title: A Fast Unified Model for Parsing and Sentence Understanding

abstract:
  Tree-structured neural networks exploit valuable syntactic parse information
as they interpret the meanings of sentences. However, they suffer from two key
technical problems that make them slow and unwieldy for large-scale NLP tasks:
they usually operate on parsed sentences and they do not directly support
batched computation. We address these issues by introducing the Stack-augmented
Parser-Interpreter Neural Network (SPINN), which combines parsing and
interpretation within a single tree-sequence hybrid model by integrating
tree-structured sentence interpretation into the linear sequential structure of
a shift-reduce parser. Our model supports batched computation for a speedup of
up to 25 times over other tree-structured models, and its integrated parser can
operate on unparsed data with little loss in accuracy. We evaluate it on the
Stanford NLI entailment task and show that it significantly outperforms other
sentence-encoding models.


title:
Boundedness of normalization generalized differential operator of
  fractional formal

abstract:
  Many authors have considered and investigated generalized fractional
differential operators. The main object of this present paper is to define a
new generalized fractional differential operator
$\mathfrak{T}^{\beta,\tau,\gamma},$ which generalized the Srivastava-Owa
operators. Moreover, we investigate of the geometric properties such as
univalency, starlikeness, convexity for their normalization. Further,
boundedness and compactness in some well known spaces, such as Bloch space for
last mention operator also are considered. Our tool is based on the generalized
hypergeometric function.


title:
Spectrally resolved detection in transient-reflectivity measurements of
  coherent optical phonons in diamond

abstract:
  Coherent optical phonons in bulk solid system play a crucial role in
understanding and designing light-matter interactions and can be detected by
the transient-reflectivity measurement. In this paper, we demonstrate
spectrally resolved detection of coherent optical phonons in diamond from
ultrashort infrared pump-probe measurements using optical band-pass filters. We
show that this enhances the sensitivity approximately 35 times in measuring the
coherent oscillations in the transient reflectivity compared with the commonly
used spectrally integrated measurement. To explain this observation, we discuss
its mechanism.


title:
Connecting Three Pivotal Concepts in K-12 Science State Standards and
  Maps of Conceptual Growth to Research in Physics Education

abstract:
  This paper describes three conceptual areas in physics that are particularly
important targets for educational interventions in K-12 science. These
conceptual areas are force and motion, conservation of energy, and geometrical
optics, which were prominent in the US national and four US state standards
that we examined. The four US state standards that were analyzed to explore the
extent to which the K-12 science standards differ in different states were
selected to include states in different geographic regions and of different
sizes. The three conceptual areas that were common to all the four state
standards are conceptual building blocks for other science concepts covered in
the K-12 curriculum. Since these three areas have been found to be ripe with
deep student misconceptions that are resilient to conventional physics
instruction, the nature of difficulties in these areas is described in some
depth, along with pointers towards approaches that have met with some success
in each conceptual area.


title:
Surveying Instructors' Attitudes and Approaches to Teaching Quantum
  Mechanics

abstract:
  Understanding instructor attitudes and approaches to teaching quantum
mechanics can be helpful in developing research-based learning tools. Here we
discuss the findings from a survey in which 13 instructors reflected on issues
related to quantum mechanics teaching. Topics included opinions about the goals
of a quantum mechanics course, general challenges in teaching the subject,
student preparation for the course, comparison between their own learning of
quantum mechanics vs. how they teach it and the extent to which contemporary
topics are incorporated into the syllabus.


title:
Analysis of the $D_{s3}^*(2860)$ as a D-wave $c\bar{s}$ meson with QCD
  sum rules

abstract:
  In this article, we assign the $D_{s3}^*(2860)$ to be a D-wave $c\bar{s}$
meson, and study the mass and decay constant of the $D_{s3}^*(2860)$ with the
QCD sum rules by calculating the contributions of the vacuum condensates up to
dimension-6 in the operator product expansion. The predicted mass
$M_{D_{s3}^*}=(2.86\pm0.10)\,\rm{GeV}$ is in excellent agreement with the
experimental value $M_{D_{s3}^*}=(2860.5\pm 2.6 \pm 2.5\pm 6.0)\,\rm{ MeV}$
from the LHCb collaboration. The present prediction supports assigning the
$D_{s3}^*(2860)$ to be the D-wave $c\bar{s}$ meson.


title:
First-principles study of the terahertz third-order nonlinear response
  of metallic armchair graphene nanoribbons

abstract:
  We compute the terahertz third-order nonlinear conductance of metallic
armchair graphene nanoribbons using time-dependent perturbation theory.
Significant enhancement of the intrinsic third-order conductance over the
result for instrinsic 2D single-layer graphene is observed over a wide range of
temperatures. We also investigate the nonlinear response of extrinsic metallic
acGNR with |E_F|<<200 meV. We find that the third-order conductance exhibits a
strong Fermi level dependence at low temperatures. A third-order critical field
strength of between 1 and 5 kV/m is computed for the Kerr conductance as a
function of temperature. For the third-harmonic conductance, the minimum
critical field is computed to be about about 5 kV/m.


title:
A Survey of Stealth Malware: Attacks, Mitigation Measures, and Steps
  Toward Autonomous Open World Solutions

abstract:
  As our professional, social, and financial existences become increasingly
digitized and as our government, healthcare, and military infrastructures rely
more on computer technologies, they present larger and more lucrative targets
for malware. Stealth malware in particular poses an increased threat because it
is specifically designed to evade detection mechanisms, spreading dormant, in
the wild for extended periods of time, gathering sensitive information or
positioning itself for a high-impact zero-day attack. Policing the growing
attack surface requires the development of efficient anti-malware solutions
with improved generalization to detect novel types of malware and resolve these
occurrences with as little burden on human experts as possible. In this paper,
we survey malicious stealth technologies as well as existing solutions for
detecting and categorizing these countermeasures autonomously. While machine
learning offers promising potential for increasingly autonomous solutions with
improved generalization to new malware types, both at the network level and at
the host level, our findings suggest that several flawed assumptions inherent
to most recognition algorithms prevent a direct mapping between the stealth
malware recognition problem and a machine learning solution. The most notable
of these flawed assumptions is the closed world assumption: that no sample
belonging to a class outside of a static training set will appear at query
time. We present a formalized adaptive open world framework for stealth malware
recognition and relate it mathematically to research from other machine
learning domains.


title:
Hight-order Noether's Theorem for Nonsmooth Extremals of Isoperimetric
  Variational Problems with Time Delay

abstract:
  We obtain a nonsmooth higher-order extension of Noether's symmetry theorem
for variational isoperimetric problems with delayed arguments. The result is
proved to be valid in the class of Lipschitz functions, as long as the delayed
higher-order Euler--Lagrange extremals are restricted to those that satisfy the
delayed higher-order DuBois--Reymond necessary optimality condition. The
important case of delayed isoperimetric optimal control problems is considered
as well.


title:
Davenport constant of the multiplicative semigroup of the ring
  $\mathbb{Z}_{n_1}\oplus\cdots\oplus \mathbb{Z}_{n_r}$

abstract:
  Given a finite commutative semigroup $\mathcal{S}$ (written additively),
denoted by ${\rm D}(\mathcal{S})$ the Davenport constant of $\mathcal{S}$,
namely the least positive integer $\ell$ such that for any $\ell$ elements
$s_1,\ldots,s_{\ell}\in \mathcal{S}$ there exists a set $I\subsetneq [1,\ell]$
for which $\sum_{i\in I} s_i=\sum_{i=1}^{\ell} s_i$.
  Then, for any integers $r\geq 1, n_1,\ldots,n_r>1$, let
$R=\mathbb{Z}_{n_1}\oplus\cdots\oplus \mathbb{Z}_{n_r}$ be the direct sum of
these $r$ residue class rings $\mathbb{Z}_{n_1}, \ldots,\mathbb{Z}_{n_r}$.
Moreover, let $\mathcal{S}_R$ be the multiplicative semigroup of the ring $R$,
and ${\rm U}(\mathcal{S}_R)$ the group of units of $\mathcal{S}_R$. In this
paper, we prove that $${\rm D}({\rm U}(\mathcal{S}_R))+P_2\leq {\rm
D}(\mathcal{S}_R)\leq {\rm D}({\rm U}(\mathcal{S}_R))+\delta,$$ where
$P_2=\sharp\{i\in [1,r]: 2 \parallel n_i\}$ and $\delta=\sharp\{i\in [1,r]:
2\mid n_i\}.$ This corrects our previous published wrong result on this
problem.


title: Efficiency enhancement of a harmonic lasing free-electron laser

abstract:
  The harmonic lasing free-electron laser amplifier, in which two wigglers is
employed in order for the fundamental resonance of the second wiggler to
coincide with the third harmonic of the first wiggler to generate ultraviolet
radiation, is studied. A set of coupled nonlinear first-order differential
equations describing the nonlinear evolution of the system, for a long electron
bunch, is solved numerically by CYRUS code. Solutions for the non-averaged and
averaged equations are compared. Remarkable agreement is found between the
averaged and non-averaged simulation for the evolution of the third harmonic.
Thermal effects in the form of longitudinal velocity spread are also
investigated. For efficiency enhancement, the second wiggler field is set to
decrease linearly and nonlinearly at the point where the radiation of the third
harmonic saturates. The optimum starting point and the slope of the tapering of
the amplitude of the wiggler are found by a successive run of the code. It is
found that tapering can increase the saturated power of the third harmonic
considerably. In order to reduce the length of the wiggler, the prebunched
electron beam is considered.