title: Nanocapillary adhesion between parallel plates

abstract:
  Molecular dynamics simulations are used to study capillary adhesion from a
nanometer scale liquid bridge between two parallel flat solid surfaces. The
capillary force and the meniscus shape of the bridge are computed as the
separation between the solid surfaces is varied. Macroscopic theory predicts
the meniscus shape and the contribution of liquid/vapor interfacial tension to
the capillary force quite accurately for separations as small as 2 or 3
molecular diameters (1-2nm). However the total capillary force differs in sign
and magnitude from macroscopic theory for separations less than about 5nm (8-10
diameters) because of molecular layering that is not included in macroscopic
theory. For these small separations, the pressure tensor in the fluid becomes
anisotropic. The components in the plane of the surface vary smoothly and are
consistent with theory based on the macroscopic surface tension. Capillary
adhesion is affected by only the perpendicular component, which has strong
oscillations as the molecular layering changes.


title:
The spin-1/2 Kagome XXZ model in a field: competition between lattice
  nematic and solid orders

abstract:
  We study numerically the spin-1/2 XXZ model in a field on an infinite Kagome
lattice. We use different algorithms based on infinite Projected Entangled Pair
States (iPEPS) for this, namely: (i) with simplex tensors and 9-site unit cell,
and (ii) coarse-graining three spins in the Kagome lattice and mapping it to a
square-lattice model with nearest-neighbor interactions, with usual PEPS
tensors, 6- and 12-site unit cells. Similarly to our previous calculation at
the SU(2)-symmetric point (Heisenberg Hamiltonian), for any anisotropy from the
Ising limit to the XY limit, we also observe the emergence of magnetization
plateaus as a function of the magnetic field, at $m_z = \frac{1}{3}$ using 6-
9- and 12-site PEPS unit cells, and at $m_z = \frac{1}{9}, \frac{5}{9}$ and
$\frac{7}{9}$ using a 9-site PEPS unit cell, the later set-up being able to
accommodate $\sqrt{3} \times \sqrt{3}$ solid order. We also find that, at $m_z
= \frac{1}{3}$, (lattice) nematic and $\sqrt{3} \times \sqrt{3}$ VBC-order
states are degenerate within the accuracy of the 9-site simplex-method, for all
anisotropy. The 6- and 12-site coarse-grained PEPS methods produce
almost-degenerate nematic and $1 \times 2$ VBC-Solid orders. Within our
accuracy, the 6-site coarse-grained PEPS method gives slightly lower energies,
which can be explained by the larger amount of entanglement this approach can
handle, even when the PEPS unit-cell is not commensurate with the expected
ground state. Furthermore, we do not observe chiral spin liquid behaviors at
and close to the XY point, as has been recently proposed. Our results are the
first tensor network investigations of the XXZ spin chain in a field, and
reveal the subtle competition between nearby magnetic orders in numerical
simulations of frustrated quantum antiferromagnets, as well as the delicate
interplay between energy optimization and symmetry in tensor networks.


title: A new peridynamic formulation with shear deformation for elastic solid

abstract:
  We propose a new peridynamic formulation with shear deformation for linear
elastic solid. The key idea lies in subtracting the rigid body rotation part
from the total deformation. Based on the strain energy equivalence between
classic local model and non-local model, the bond force vector is derived. A
new damage rule of maximal deviatoric bond strain for elastic brittle fracture
is proposed in order to account for both the tensile damage and shear damage.
2D and 3D numerical examples are tested to verify the accuracy of the current
peridynamics. The new damage rule is applied to simulate the propagation of
Mode I, II and III cracks.


title:
On 2-diffeomorphisms with one-dimensional basic sets and a finite number
  of moduli

abstract:
  This paper is a step towards the complete topological classification of
{\Omega}-stable diffeomorphisms on an orientable closed surface, aiming to give
necessary and sufficient conditions for two such diffeomorphisms to be
topologically conjugate without assuming that the diffeomorphisms are
necessarily close to each other. In this paper we will establish such a
classification within a certain class {\Psi} of {\Omega}-stable diffeomorphisms
de- fined below. To determine whether two diffeomorphisms from this class
{\Psi} are topologically conjugate, we give (i) an algebraic description of the
dynamics on their non-trivial basic sets, (ii) a geometric description of how
invariant manifolds intersect, and (iii) define numerical invariants, called
moduli, associated to orbits of tangency of stable and unsta- ble manifolds of
saddle periodic orbits. This description determines the scheme of a
diffeomorphism, and we will show that two diffeomorphisms from {\Psi} are
topologically conjugate if and only if their schemes agree.


title: Spectrum of a singularly perturbed periodic thin waveguide

abstract:
  We consider a family $\{\Omega^\varepsilon\}_{\varepsilon>0}$ of periodic
domains in $\mathbb{R}^2$ with waveguide geometry and analyse spectral
properties of the Neumann Laplacian $-\Delta_{\Omega^\varepsilon}$ on
$\Omega^\varepsilon$. The waveguide $\Omega^\varepsilon$ is a union of a thin
straight strip of the width $\varepsilon$ and a family of small protuberances
with the so-called "room-and-passage" geometry. The protuberances are attached
periodically, with a period $\varepsilon$, along the strip upper boundary. For
$\varepsilon\to 0$ we prove a (kind of) resolvent convergence of
$-\Delta_{\Omega^\varepsilon}$ to a certain ordinary differential operator.
Also we demonstrate Hausdorff convergence of the spectrum. In particular, we
conclude that if the sizes of "passages" are appropriately scaled the first
spectral gap of $-\Delta_{\Omega^\varepsilon}$ is determined exclusively by
geometric properties of the protuberances. The proofs are carried out using
methods of homogenization theory.


title:
Kernel Risk-Sensitive Loss: Definition, Properties and Application to
  Robust Adaptive Filtering

abstract:
  Nonlinear similarity measures defined in kernel space, such as correntropy,
can extract higher-order statistics of data and offer potentially significant
performance improvement over their linear counterparts especially in
non-Gaussian signal processing and machine learning. In this work, we propose a
new similarity measure in kernel space, called the kernel risk-sensitive loss
(KRSL), and provide some important properties. We apply the KRSL to adaptive
filtering and investigate the robustness, and then develop the MKRSL algorithm
and analyze the mean square convergence performance. Compared with correntropy,
the KRSL can offer a more efficient performance surface, thereby enabling a
gradient based method to achieve faster convergence speed and higher accuracy
while still maintaining the robustness to outliers. Theoretical analysis
results and superior performance of the new algorithm are confirmed by
simulation.


title: A Landau's theorem in several complex variables

abstract:
  In one complex variable it is well known that if we consider the family of
all holomorphic functions on the unit disc that fix the origin and with first
derivative equal to 1 at the origin, then there exists a constant $\rho$,
independent of the functions, such that in the image of the unit disc of any of
the functions of the family there is a disc of universal radius $\rho.$ This is
the so celebrated Landau's theorem. Many counterexamples to an analogous result
in several complex variables exist. In this paper we introduce a class of
holomorphic maps for which one can get a Landau's theorem and a Brody-Zalcman
theorem in several complex variables.


title: Exact packing dimension of random self-similar sests

abstract:
  We extend the results previously published on exact packing dimensions of
random recursive constructions to include constructions satisfying commonly
occurring conditions. We remove the restrictive assumption that the diameter
reduction ratios between the offsping are either constant almost surely, or 0.


title:
Emergence of nontrivial magnetic excitations in a spin liquid state of
  kagome volborthite

abstract:
  When quantum fluctuations destroy underlying long-range ordered states, novel
quantum states emerge. Spin-liquid (SL) states of frustrated quantum
antiferromagnets, in which highly-correlated spins keep to fluctuate down to
very low temperatures, are prominent examples of such quantum states. SL states
often exhibit exotic physical properties, but the precise nature of the
elementary excitations behind such phenomena remains entirely elusive. Here we
utilize thermal Hall measurements that can capture the unexplored property of
the elementary excitations in SL states, and report on the observation of
anomalous excitations that may unveil the unique features of the SL state. Our
principal finding is a negative thermal Hall conductivity (k_xy) which the
charge-neutral spin excitations in a gapless SL state of the two-dimensional
kagome insulator volborthite Cu_3V_2O_7(OH)_2 \cdot 2H_2O exhibit, in much the
same way in which charged electrons give rise to the conventional electric Hall
effect. We find that k_xy is absent in the high-temperature paramagnetic state
and develops upon entering the SL state in accordance with the growth of the
short-range spin correlations, demonstrating that k_xy is a key signature of
the elementary excitation formed in the SL state. These results suggest the
emergence of nontrivial elementary excitations in the gapless SL state which
feel the presence of fictitious magnetic flux, whose effective Lorentz force is
found to be less than 1/100 of that experienced by free electrons.


title:
On a New Approach for Constructing Wormholes in Einstein-Born-Infeld
  Gravity

abstract:
  We study a new approach for the wormhole construction in Einstein-Born-Infeld
gravity, which does not require exotic matters in the Einstein equation. The
Born-Infeld field equation is not modified from "coordinate independent"
conditions of continuous metric tensor and its derivatives, even though the
Born-Infeld fields have discontinuities in their derivatives at the throat in
general. We study the relation of the newly introduced conditions with the
usual continuity equation for the energy-momentum tensor and the gravitational
Bianchi identity. We find that there is no violation of energy conditions for
the Born-Infeld fields contrary to the usual approaches. The exoticity of
energy-momentum tensor is not essential for sustaining wormholes. Some open
problems are discussed.


title: Chiral Quantum Optics

abstract:
  At the most fundamental level, the interaction between light and matter is
manifested by the emission and absorption of single photons by single quantum
emitters. Controlling light--matter interaction is the basis for diverse
applications ranging from light technology to quantum--information processing.
Many of these applications are nowadays based on photonic nanostructures
strongly benefitting from their scalability and integrability. The confinement
of light in such nanostructures imposes an inherent link between the local
polarization and propagation direction of light. This leads to {\em chiral
light--matter interaction}, i.e., the emission and absorption of photons depend
on the propagation direction and local polarization of light as well as the
polarization of the emitter transition. The burgeoning research field of {\em
chiral quantum optics} offers fundamentally new functionalities and
applications both for single emitters and ensembles thereof. For instance, a
chiral light--matter interface enables the realization of integrated
non--reciprocal single--photon devices and deterministic spin--photon
interfaces. Moreover, engineering directional photonic reservoirs opens new
avenues for constructing complex quantum circuits and networks, which may be
applied to simulate a new class of quantum many--body systems.


title: Exploring the Front Touch Interface for Virtual Reality Headsets

abstract:
  In this paper, we propose a new interface for virtual reality headset: a
touchpad in front of the headset. To demonstrate the feasibility of the front
touch interface, we built a prototype device, explored VR UI design space
expansion, and performed various user studies. We started with preliminary
tests to see how intuitively and accurately people can interact with the front
touchpad. Then, we further experimented various user interfaces such as a
binary selection, a typical menu layout, and a keyboard. Two-Finger and
Drag-n-Tap were also explored to find the appropriate selection technique. As a
low-cost, light-weight, and in low power budget technology, a touch sensor can
make an ideal interface for mobile headset. Also, front touch area can be large
enough to allow wide range of interaction types such as multi-finger
interactions. With this novel front touch interface, we paved a way to new
virtual reality interaction methods.


title:
Constraining axion coupling constants from measuring the Casimir
  interaction between polarized test bodies

abstract:
  We propose an experiment for measuring the effective Casimir pressure between
two parallel SiC plates with aligned nuclear spins. The prospective constraints
on an axion-neutron coupling constant for both hadronic and GUT axions are
calculated using the process of one-axion exchange. For this purpose, a general
expression for the additional pressure arising between two polarized plates due
to the exchange of one axion between their constituent fermions is derived. We
demonstrate that only the polarization component perpendicular to the plates
contribute to the pressure. The obtained pressure can be both repulsive and
attractive depending on whether the polarizations of both plates are
unidirectional or directed in opposite directions. It is shown that although
the constraints on an axion-electron coupling obtained in the case of
magnetized plates are not competitive, the constraints on an axion-neutron
coupling found for plates with polarized nuclear spins are of the same order of
magnitude of those obtained previously for the GUT axions alone using the
process of two-axion exchange. The proposed experiment allows also to
strengthen the presently known constraints on the axion-neutron coupling
constants of GUT axions by using both processes of one- and two-axion exchange.


title:
Stability estimate for an inverse problem for the Schr{\"o}dinger
  equation in a magnetic field with time-dependent coefficient

abstract:
  We study the stability issue in the inverse problem of determining the
magnetic field and the time-dependent electric potential appearing in the
Schr\"odinger equation, from boundary observations. We prove in dimension 3 or
greater, that the knowledge of the Dicrichlet-to-Neumann map stably determines
the magnetic field and the electric potential.


title:
Extension of Relativistic-Microwave Theory of Ball Lightning Including
  Long-term Losses And Stability

abstract:
  After centuries, the long-standing problem of the nature of ball lightning
may be closer to a solution. The relativistic-microwave theory of ball
lightning recently proposed by Wu accounts for many of the leading
characteristics of ball lightning, which most previous theories have failed to
do. It involves the impact of a lightning-caused relativistic electron bunch to
soil, producing an EM pulse that forms a plasma bubble. While the theory
presents a plausible account of ball-lightning formation, storing
electromagnetic energy long enough to account for the observed lifetime of such
objects was not demonstrated. Here we show how such a structure can develop the
high Q factor (~10^10) needed for the observed lifetimes of ~seconds for ball
lightning, and show that the structure is radially stable, given certain
assumptions.


title: Numerical tolerance for spectral decompositions of random matrices

abstract:
  We precisely quantify the impact of statistical error in the quality of a
numerical approximation to a random matrix eigendecomposition, and under mild
conditions, we use this to introduce an optimal numerical tolerance for
residual error in spectral decompositions of random matrices. We demonstrate
that terminating an eigendecomposition algorithm when the numerical error and
statistical error are of the same order results in computational savings with
no loss of accuracy. We also repair a flaw in a ubiquitous termination
condition, one in wide employ in several computational linear algebra
implementations. We illustrate the practical consequences of our stopping
criterion with an analysis of simulated and real networks. Our theoretical
results and real-data examples establish that the tradeoff between statistical
and numerical error is of significant import for data science.


title: Averaged Lema\^itre-Tolman-Bondi dynamics

abstract:
  We consider cosmological backreaction effects in Buchert's averaging
formalism on the basis of an explicit solution of the Lema\^itre-Tolman-Bondi
(LTB) dynamics which is linear in the LTB curvature parameter and has an
inhomogeneous bang time. The volume Hubble rate is found in terms of the volume
scale factor which represents a derivation of the simplest phenomenological
solution of Buchert's equations in which the fractional densities corresponding
to average curvature and kinematic backreaction are explicitly determined by
the parameters of the underlying LTB solution at the boundary of the averaging
volume. This configuration represents an exactly solvable toy model but it does
not adequately describe our "real" Universe.


title:
Indications of stellar prominence oscillations on fast rotating stars:
  the cases of HK Aqr and PZ Tel

abstract:
  We present the analysis of six nights of spectroscopic monitoring of two
young and fast rotating late-type stars, namely the dMe star HK Aqr and the
dG/dK star PZ Tel. On both stars we detect absorption features reminiscent of
signatures of co-rotating cool clouds or prominences visible in H$\alpha$.
Several prominences on HK Aqr show periodic variability in the prominence
tracks which follow a sinusoidal motion (indication of prominence
oscillations). On PZ Tel we could not find any periodic variability in the
prominence tracks. By fitting sinusoidal functions to the prominence tracks we
derive amplitudes and periods which are similar to those of large amplitude
oscillations seen in solar prominences. In one specific event we also derive a
periodic variation of the prominence track in the H$\beta$ spectral line which
shows an anti-phase variation with the one derived for the H$\alpha$ spectral
line. Using these parameters and estimated mass density of a prominence on HK
Aqr we derive a minimum magnetic field strength of $\sim$2G. The relatively low
strength of the magnetic field is explained by the large height of this stellar
prominence ($\ge$ 0.67 stellar radii above the surface).


title: FCNC transition of $B$ to $a_1$ with LCSR

abstract:
  The $B\to a_1 \ell^+ \ell^-$ decays occur by the electroweak penguin and box
diagrams which can be performed through the flavor changing neutral current
(FCNC). We calculate the form factors of the FCNC $B \to a_1$ transitions in
the light--cone sum rules approach, up to twist--4 distribution amplitudes of
the axial vector meson $a_1$. Forward--backward asymmetry, as well as branching
ratios of $B\to a_1\ell^{+}\ell^{-}$, and $B\to a_1 \gamma$ decays are
considered. A comparison is also made between our results and the predictions
of other methods.


title: Regge approach to the reaction of $\gamma N \to K^* \Lambda$

abstract:
  Photoproduction of $K^*$ vector mesons off nucleon is investigated within the
Regge framework where the electromagnetic vertex of $\gamma K^*K^*$ fully takes
into account the magnetic dipole and electric quadrupole moments of spin-1
$K^*$ vector meson. The $t$-channel $K^*(892)$, $K(494)$ and $\kappa(800)$
meson exchanges are considered for the analysis of the production mechanism.
The experimentally observed rapid decrease of the cross sections for the
$\gamma p \to K^{*+} \Lambda$ reaction beyond the resonance region is well
reproduced by the dominance of the exchange of $K$-meson trajectory. The role
of the scalar $\kappa$-meson trajectory is found to be minor in both $\gamma p$
and $\gamma n$ reactions. The cross sections for the $\gamma n \to K^{*0}
\Lambda$ reaction are predicted to be about twice those of the $\gamma p \to
K^{*+}\Lambda$ reaction. The role of the $K^*$ electromagnetic multipoles and
the proton anomalous magnetic moment is studied through the total and
differential cross sections and spin/parity asymmetries. We suggest the
measurement of the photon polarization asymmetry as a tool for identifying the
role of the magnetic dipole and electric quadrupole moments of the $K^*$ vector
meson.


title:
Study of Eclipsing Binary and Multiple Systems in OB Associations IV:
  Cas OB6 Member DN Cas

abstract:
  An early-type, massive, short-period ($P_{\rm orb}=2^{\rm d}.310951$)
eclipsing spectroscopic binary DN Cas has been re-visited with new spectral and
photometric data. The masses and radii of the components have been obtained as
$M_1=19.04\pm0.07 M_\odot$, $M_2=13.73\pm 0.05M_\odot$ and $R_1=7.22\pm0.06
R_\odot$, $R_2=5.79\pm0.06R_\odot$, respectively. Both components present
synchronous rotation ($V_{\rm rot1}=160\,$km s$^{-1}$, $V_{\rm rot2}=130\,$km
s$^{-1}$) with their orbit. Orbital period analysis yielded a physically bound
additional component in the system with a minimum mass of $M_3=0.88 M_\odot$
orbiting in an eccentric orbit ($e=0.37\pm0.2$) with an orbital period of
$P_{12}=42\pm9$ yrs. High precision absolute parameters of the system allowed
us to derive a distance to DN Cas as 1.7$\pm$0.2 kpc which locates the system
within the borders of the Cas OB6 association (d=1.8 kpc; Mel'nik & Dambis,
2009). The space velocities and the age of DN Cas are in agreement with those
of Cas OB6. The age of DN Cas ($\tau=$3-5 Myr) is found to be 1-2 Myr older
than the embedded clusters (IC 1795, IC 1805 and IC 1848) in the Cas OB6
association, which implies a sequential star formation in the association.


title: Strongly Interacting Fermi Gases

abstract:
  The experimental realization of stable, ultracold Fermi gases near a Feshbach
resonance allows to study gases with attractive interactions of essentially
arbitrary strength. They extend the classic paradigm of BCS into a regime which
has never been accessible before. We review the theoretical concepts which have
been developed in this context, including the Tan relations and the notion of
fixed points at zero density, which are at the origin of universality. We
discuss in detail the universal thermodynamics of the unitary Fermi gas which
allows a fit free comparison between theory and experiment for this strongly
interacting system. In addition, we adress the consequences of scale invariance
at infinite scattering length and the subtle violation of scale invariance in
two dimensions. Finally we discuss the Fermionic excitation spectrum accessible
in momentum resolved RF-spectroscopy and the origin of universal lower bounds
for the shear viscosity and the spin diffusion constant.


title:
Improving Fisher matrix forecasts for galaxy surveys: window function,
  bin cross-correlation, and bin redshift uncertainty

abstract:
  The Fisher matrix is a widely used tool to forecast the performance of future
experiments and approximate the likelihood of large data sets. Most of the
forecasts for cosmological parameters in galaxy clustering studies rely on the
Fisher matrix approach for large-scale experiments like DES, Euclid, or SKA.
Here we improve upon the standard method by taking into account three effects:
the finite window function, the correlation between redshift bins, and the
uncertainty on the bin redshift. The first two effects are negligible only in
the limit of infinite surveys. The third effect, on the contrary, is negligible
for infinitely small bins. Here we show how to take into account these effects
and what the impact on forecasts of a Euclid-type experiment will be. The main
result of this article is that the windowing and the bin cross-correlation
induce a considerable change in the forecasted errors, of the order of 10-30%
for most cosmological parameters, while the redshift bin uncertainty can be
neglected for bins smaller than $\Delta z = 0.1$ roughly.


title:
A PSF-based approach to Kepler/K2 data. II. Exoplanet candidates in
  Praesepe (M 44)

abstract:
  In this work we keep pushing K2 data to a high photometric precision, close
to that of the Kepler main mission, using a PSF-based, neighbour-subtraction
technique, which also overcome the dilution effects in crowded environments. We
analyse the open cluster M 44 (NGC 2632), observed during the K2 Campaign 5,
and extract light curves of stars imaged on module 14, where most of the
cluster lies. We present two candidate exoplanets hosted by cluster members and
five by field stars. As a by-product of our investigation, we find 1680
eclipsing binaries and variable stars, 1071 of which are new discoveries. Among
them, we report the presence of a heartbeat binary star. Together with this
work, we release to the community a catalogue with the variable stars and the
candidate exoplanets found, as well as all our raw and detrended light curves.


title: A heat equation on a quaternionic contact manifold

abstract:
  A quaternionic contact (qc) heat equation and the corresponding qc energy
functional are introduced. It is shown that the qc energy functional is
monotone non-increasing along the qc heat equation on a compact qc manifold
provided certain positivity conditions are satisfied.


title: Chabauty limits of simple groups acting on trees

abstract:
  Let $T$ be a locally finite tree without vertices of degree $1$. We show that
among the closed subgroups of $\mathrm{Aut}(T)$ acting with a bounded number of
orbits, the Chabauty-closure of the set of topologically simple groups is the
set of groups without proper open subgroup of finite index. Moreover, if all
vertices of $T$ have degree $\geq 3$, then the set of isomorphism classes of
topologically simple closed subgroups of $\mathrm{Aut}(T)$ acting doubly
transitively on $\partial T$ carries a natural compact Hausdorff topology
inherited from Chabauty. Some of our considerations are valid in the context of
automorphism groups of locally finite connected graphs. Applications to
Weyl-transitive automorphism groups of buildings are also presented.


title:
Are Safer Looking Neighborhoods More Lively? A Multimodal Investigation
  into Urban Life

abstract:
  Policy makers, urban planners, architects, sociologists, and economists are
interested in creating urban areas that are both lively and safe. But are the
safety and liveliness of neighborhoods independent characteristics? Or are they
just two sides of the same coin? In a world where people avoid unsafe looking
places, neighborhoods that look unsafe will be less lively, and will fail to
harness the natural surveillance of human activity. But in a world where the
preference for safe looking neighborhoods is small, the connection between the
perception of safety and liveliness will be either weak or nonexistent. In this
paper we explore the connection between the levels of activity and the
perception of safety of neighborhoods in two major Italian cities by combining
mobile phone data (as a proxy for activity or liveliness) with scores of
perceived safety estimated using a Convolutional Neural Network trained on a
dataset of Google Street View images scored using a crowdsourced visual
perception survey. We find that: (i) safer looking neighborhoods are more
active than what is expected from their population density, employee density,
and distance to the city centre; and (ii) that the correlation between
appearance of safety and activity is positive, strong, and significant, for
females and people over 50, but negative for people under 30, suggesting that
the behavioral impact of perception depends on the demographic of the
population. Finally, we use occlusion techniques to identify the urban features
that contribute to the appearance of safety, finding that greenery and street
facing windows contribute to a positive appearance of safety (in agreement with
Oscar Newman's defensible space theory). These results suggest that urban
appearance modulates levels of human activity and, consequently, a
neighborhood's rate of natural surveillance.


title:
The limits on the strong Higgs sector parameters in the presence of new
  vector resonances

abstract:
  In this paper, we investigate how the LHC data limit the Higgs-related
couplings in the effective description of a strongly interacting extension of
the Standard model. The Higgs boson is introduced as a scalar composite state
and it is followed in the mass hierarchy by an $SU(2)$ triplet of vector
composites. The limits are calculated from the constraints obtained in the
recent ATLAS+CMS combined analysis of the data from 2011 and 2012. We find that
the data prefer the scenario where the Higgs couplings to the electroweak gauge
bosons differ from its couplings to the vector triplet. We also investigate the
unitarity limits of the studied effective model for the experimentally
preferred values of the Higgs couplings. We find from the
$\pi\pi\rightarrow\pi\pi$ scattering amplitudes that for the vector resonance
masses between one and two TeV significant portions of the experimentally
allowed regions are well below the unitarity limit. We also evaluate how the
existing ATLAS and CMS Run-2 data restrict our model with the upper bounds on
the resonance production cross section times its branching ratio for various
decay channels. The masses in the range $1\;\mbox{TeV}\leq M_\rho\leq
2\;\mbox{TeV}$ are not excluded in parts or even full parameter space of our
theory.


title:
Volume nanograting formation in laser-silica interaction as a result of
  the 1D plasma-resonance ionization instability

abstract:
  The initial stage of the small-scale ionization-induced instability
developing inside the fused silica volume exposed to the femtosecond laser
pulse is studied as a possible initial cause of the self-organized nanograting
formation. We have calculated the spatial spectra of the instability with the
electron-hole diffusion taken into account for the first time and have found
that it results in the formation of some hybrid (diffusion-wave) 1D structure
with the spatial period determined as geometrical mean of the laser wavelength
and characteristic diffusion length of the process considered. Near the
threshold of the instability this period occurs to be approximately equal to
the laser half-wavelength in the silica, close to the one experimentally
observed.


title:
The Mid-Infrared Luminosity Evolution and Luminosity Function of Quasars
  with SDSS and WISE

abstract:
  We determine the 22$\mu$m luminosity evolution and luminosity function for
quasars from a data set of over 20,000 objects obtained by combining
flux-limited Sloan Digital Sky Survey optical and Wide field Infrared Survey
Explorer mid-infrared data. We apply methods developed in previous works to
access the intrinsic population distributions non-parametrically, taking into
account the truncations and correlations inherent in the data. We find that the
population of quasars exhibits positive luminosity evolution with redshift in
the mid-infrared, but with considerably less mid-infrared evolution than in the
optical or radio bands. With the luminosity evolutions accounted for, we
determine the density evolution and local mid-infrared luminosity function. The
latter displays a sharp flattening at local luminosities below $\sim 10^{31}$
erg sec$^{-1}$ Hz$^{-1}$, which has been reported previously at 15 $\mu$m for
AGN classified as both type-1 and type-2. We calculate the integrated total
emission from quasars at 22 $\mu$m and find it to be a small fraction of both
the cosmic infrared background light and the integrated emission from all
sources at this wavelength.


title:
Learning Semantically Coherent and Reusable Kernels in Convolution
  Neural Nets for Sentence Classification

abstract:
  The state-of-the-art CNN models give good performance on sentence
classification tasks. The purpose of this work is to empirically study
desirable properties such as semantic coherence, attention mechanism and
reusability of CNNs in these tasks. Semantically coherent kernels are
preferable as they are a lot more interpretable for explaining the decision of
the learned CNN model. We observe that the learned kernels do not have semantic
coherence. Motivated by this observation, we propose to learn kernels with
semantic coherence using clustering scheme combined with Word2Vec
representation and domain knowledge such as SentiWordNet. We suggest a
technique to visualize attention mechanism of CNNs for decision explanation
purpose. Reusable property enables kernels learned on one problem to be used in
another problem. This helps in efficient learning as only a few additional
domain specific filters may have to be learned. We demonstrate the efficacy of
our core ideas of learning semantically coherent kernels and leveraging
reusable kernels for efficient learning on several benchmark datasets.
Experimental results show the usefulness of our approach by achieving
performance close to the state-of-the-art methods but with semantic and
reusable properties.


title: Phase Transition in IrTe$_2$ induced by spin-orbit coupling

abstract:
  IrTe$_2$ has been renewed as an interesting system showing competing
phenomenon between a questionable density-wave transition near 270 K followed
by superconductivity with doping of high atomic number materials. Higher atomic
numbers of Te and Ir supports strong spin-orbital coupling in this system.
Using dynamical mean field theory with LDA band structure I have introduced
Rashba spin orbit coupling in this system to get the interpretation for
anomalous resistivity and related transition in this system. While no
considerable changes are observed in DMFT results of Ir-5d band other than
orbital selective pseudogap pinned to Fermi level, Te-p band shows a van Hove
singularity at the Fermi level except low temperature. Finally I discuss the
implications of these results in theoretical understanding of ordering in
IrTe$_2$.


title:
Virtual states and generalized completeness relation in the Friedrichs
  Model

abstract:
  We study the well-known Friedrichs model, in which a discrete state is
coupled to a continuum state. By examining the pole behaviors of the Friedrichs
model in a specific form factor thoroughly, we find that, in general, when the
bare discrete state is below the threshold of the continuum state, there should
also be a virtual-state pole accompanying the bound-state pole originating from
the bare discrete state as the coupling is turned on. There are also other
second-sheet poles originating from the singularities of the form factor. We
give a general argument for the existence of these two kinds of states. As the
coupling is increased to a certain value, the second-sheet poles may merge and
become higher-order poles. We then discuss the completeness relations
incorporating bound states, virtual states, and resonant states corresponding
to higher-order poles.


title: Dark Matter From f(R,T) Gravity

abstract:
  We consider f(R,T) modified theory of gravity, in which the gravitational
Lagrangian is given by an arbitrary function of the Ricci scalar and the trace
of the energy-momentum tensor of the matter, in order to investigate the
dark-matter effects on the galaxy scale. We obtain the metric components for a
spherically symmetric and static spacetime in the vicinity of general
relativity solutions. However, we concentrate on a specific model of the theory
where the matter is minimally coupled to the geometry, and derive the metric
components in the galactic halo. Then, we fix the components by the rotational
velocities of the galaxies for the model, and show that the mass corresponding
to the interaction term (which appears in the Einstein modified field equation)
leads to a flat rotation curve in the halo of galaxies. In addition, for the
proposed model, the light-deflection angle has been derived and drawn using
some observed data.


title: Labeling Topics with Images using Neural Networks

abstract:
  Topics generated by topic models are usually represented by lists of $t$
terms or alternatively using short phrases and images. The current
state-of-the-art work on labeling topics using images selects images by
re-ranking a small set of candidates for a given topic. In this paper, we
present a more generic method that can estimate the degree of association
between any arbitrary pair of an unseen topic and image using a deep neural
network. Our method has better runtime performance $O(n)$ compared to $O(n^2)$
for the current state-of-the-art method, and is also significantly more
accurate.


title: On a notion of partially conditionally identically distributed sequences

abstract:
  A notion of conditionally identically distributed (c.i.d.) sequences has been
studied as a form of stochastic dependence that is weaker than exchangeability,
but is equivalent to exchangeability for stationary sequences. In this article
we extend this notion to families of sequences. Paralleling the extension from
exchangeability to partial exchangeability in the sense of de Finetti, we
propose a notion of partially c.i.d. dependence, that is equivalent to partial
exchangeability for stationary processes. Partially c.i.d. families of
sequences preserve attractive limit properties of partial exchangeability, and
are asymptotically partially exchangeable. Moreover, we provide strong laws of
large numbers and two central limit theorems. Our focus is on the asymptotic
agreement of predictions and empirical means, which lies in the foundations of
Bayesian statistics. Natural examples are interacting randomly reinforced
processes satisfying certain conditions on the reinforcement.


title: Hot origin of the Little Bang

abstract:
  Ultrarelativistic heavy ion collisions produce a quark-gluon matter which
lies in the future light cone originating from given points on the $t=z=0$
plane of the Minkowski spacetime manifold. We show that in a weak coupling
regime the Minkowski vacuum of massless fields presents itself in the "Little
Bang" region as a thermal state of low $p_{T}$ particles, in close analogy to
the Unruh effect for uniformly accelerated observers which are causally
restricted to a Rindler wedge. It can shed some light on the mechanisms of
early time thermalization in ultrarelativistic heavy ion collisions.


title: Absence of Anderson localization in certain random lattices

abstract:
  We report on the transition between an Anderson localized regime and a
conductive regime in a 1D scattering system with correlated disorder. We show
experimentally that when long-range correlations, in the form of a power-law
spectral density with power larger than 2, are introduced the localization
length becomes much bigger than the sample size and the transmission peaks
typical of an Anderson localized system merge into a pass band. As other forms
of long-range correlations are known to have the opposite effect, i.e. to
enhance localization, our results show that care is needed when discussing the
effects of correlations, as different kinds of long-range correlations can give
rise to very different behavior.


title:
Comparison of Geometric and Probabilistic Shaping with Application to
  ATSC 3.0

abstract:
  In this work, geometric shaping (GS) and probabilistic shaping (PS) for the
AWGN channel is reviewed. Both approaches are investigated in terms of
symbol-metric decoding (SMD) and bit-metric decoding (BMD). For GS, an
optimization algorithm based on differential evolution is formulated.
Achievable rate analysis reveals that GS suffers from a 0.4 dB performance
degradation compared to PS when BMD is used. Forward-error correction
simulations of the ATSC 3.0 modulation and coding formats (modcods) confirm the
theoretical findings. In particular, PS enables seamless rate adaptation with
one single modcod and it outperforms ATSC 3.0 GS modcods by more than 0.5 dB
for spectral efficiencies larger than 3.2 bits per channel use.


title:
Graph Representation for Configurational Properties of Crystalline
  Solids

abstract:
  We propose representation of configurational physical quantities and
microscopic structures for multicomponent system on lattice, by extending a
concept of generalized Ising model (GIM) to graph theory. We construct graph
Laplacian (and adjacency matrix) composed of symmetry-equivalent neighboring
edges, whose landscape of spectrum explicitly represents GIM description of
structures as well as low-dimensional topological information in terms of
graph. The proposed representation indicates the importance of linear
combination of graph to further investigate the role of spatial constraint on
equilibrium properties in classical systems. We demonstrate that spectrum for
such linear combination of graph can find out additional characteristic
microscopic structures compared with GIM-based descriptions for given set of
figures on the same low-dimensional configuration space, coming from the
proposed representation explicitly having more structural information for e.g.,
higher-order closed links of selected element. Statistical interdependence for
density of microscopic states including graph representation for structures is
also examined, which exhibits similar behavior that has been seen for GIM
description of the microscopic structures.


title:
R package imputeTestbench to compare imputations methods for univariate
  time series

abstract:
  This paper describes the R package imputeTestbench that provides a testbench
for comparing imputation methods for missing data in univariate time series.
The imputeTestbench package can be used to simulate the amount and type of
missing data in a complete dataset and compare filled data using different
imputation methods. The user has the option to simulate missing data by
removing observations completely at random or in blocks of different sizes.
Several default imputation methods are included with the package, including
historical means, linear interpolation, and last observation carried forward.
The testbench is not limited to the default functions and users can add or
remove additional methods using a simple two-step process. The testbench
compares the actual missing and imputed data for each method with different
error metrics, including RMSE, MAE, and MAPE. Alternative error metrics can
also be supplied by the user. The simplicity of use and significant reduction
in time to compare imputation methods for missing data in univariate time
series is a significant advantage of the package. This paper provides an
overview of the core functions, including a demonstration with examples.


title:
Universal Shape Replicators via Self-Assembly with Attractive and
  Repulsive Forces

abstract:
  We show how to design a universal shape replicator in a self-assembly system
with both attractive and repulsive forces. More precisely, we show that there
is a universal set of constant-size objects that, when added to any unknown
hole-free polyomino shape, produces an unbounded number of copies of that shape
(plus constant-size garbage objects). The constant-size objects can be easily
constructed from a constant number of individual tile types using a constant
number of preprocessing self-assembly steps. Our construction uses the
well-studied 2-Handed Assembly Model (2HAM) of tile self-assembly, in the
simple model where glues interact only with identical glues, allowing glue
strengths that are either positive (attractive) or negative (repulsive), and
constant temperature (required glue strength for parts to hold together). We
also require that the given shape has specified glue types on its surface, and
that the feature size (smallest distance between nonincident edges) is bounded
below by a constant. Shape replication necessarily requires a self-assembly
model where parts can both attach and detach, and this construction is the
first to do so using the natural model of negative/repulsive glues (also
studied before for other problems such as fuel-efficient computation); previous
replication constructions require more powerful global operations such as an
"enzyme" that destroys a subset of the tile types.


title: Spin-orbit coupled two-electron Fermi gases of ytterbium atoms

abstract:
  We demonstrate all-optical implementation of spin-orbit coupling (SOC) in a
two-electron Fermi gas of $^{173}$Yb atoms by coupling two hyperfine ground
states with a narrow optical transition. Due to the SU($N$) symmetry of the
$^1$S$_0$ ground-state manifold which is insensitive to external magnetic
fields, an optical AC Stark effect is applied to split the ground spin states,
which exhibits a high stability compared with experiments on alkali and
lanthanide atoms, and separate out an effective spin-1/2 subspace from other
hyperfine levels for the realization of SOC. The dephasing spin dynamics when a
momentum-dependent spin-orbit gap being suddenly opened and the asymmetric
momentum distribution of the spin-orbit coupled Fermi gas are observed as a
hallmark of SOC. The realization of all-optical SOC for ytterbium fermions
should offer a new route to a long-lived spin-orbit coupled Fermi gas and
greatly expand our capability in studying novel spin-orbit physics with
alkaline-earth-like atoms.


title:
Coherent control over three-dimensional spin polarization for the
  spin-orbit coupled surface state of Bi$_2$Se$_3$

abstract:
  Interference of spin-up and spin-down eigenstates depicts spin rotation of
electrons, which is a fundamental concept of quantum mechanics and accepts
technological challenges for the electrical spin manipulation. Here, we
visualize this coherent spin physics through laser spin- and angle-resolved
photoemission spectroscopy on a spin-orbital entangled surface-state of a
topological insulator. It is unambiguously revealed that the linearly polarized
laser can simultaneously excite spin-up and spin-down states and these quantum
spin-basis are coherently superposed in photoelectron states. The superposition
and the resulting spin rotation is arbitrary manipulated by the direction of
the laser field. Moreover, the full observation of the spin rotation displays
the phase of the quantum states. This presents a new facet of
laser-photoemission technique for investigation of quantum spin physics opening
new possibilities in the field of quantum spintronic applications.


title: Central Configurations and Mutual Differences

abstract:
  Central configurations are solutions of the equations $\lambda
m_j\boldsymbol{q}_j = \frac{\partial U}{\partial \boldsymbol{q}_j}$, where $U$
denotes the potential function and each $\boldsymbol{q}_j$ is a point in the
$d$-dimensional Euclidean space $E\cong {\mathbb R}^d$, for $j=1,\ldots, n$. We
show that the vector of the mutual differences $\boldsymbol{q}_{ij} =
\boldsymbol{q}_i - \boldsymbol{q}_j$ satisfies the equation
$-\frac{\lambda}{\alpha} \boldsymbol{q} = P_m(\Psi(\boldsymbol{q}))$, where
$P_m$ is the orthogonal projection over the spaces of $1$-cocycles and
$\Psi(\boldsymbol{q}) = \frac{\boldsymbol{q}}{|\boldsymbol{q}|^{\alpha+2}}$. It
is shown that differences $\boldsymbol{q}_{ij}$ of central configurations are
critical points of an analogue of $U$, defined on the space of $1$-cochains in
the Euclidean space $E$, and restricted to the subspace of $1$-cocycles. Some
generalizations of well known facts follow almost immediately from this
approach.


title: Robust split-plot designs for model misspecification

abstract:
  Many existing methods for constructing optimal split-plot designs, such as
D-optimal designs, only focus on minimizing the variances and covariances of
the estimation for the fitted model. However, the underlying true model is
usually complicated and unknown and the fitted model is often misspecified. If
there exist significant effects that are not included in the model, then the
estimation could be highly biased. Therefore, a good split-plot designs should
be able to simultaneously control the variances/covariances and the bias of the
estimation. In this paper, we propose a new method for constructing optimal
split-plot designs that are robust for model misspecification. We provide a
general form of the loss function used for the D-optimal minimax criterion and
apply it to searching for robust split-plot designs. To more efficiently
construct designs, we develop an algorithm which combines the anneal algorithm
and point-exchange algorithm. We modify the update formulas for calculating the
determinant and inverse of the updated matrix and apply them to increasing the
computing speed for our developed program.


title: Growth and engineering of perovskite SrIrO3 thin films

abstract:
  5d transition-metal-based oxides display emergent phenomena due to the
competition between the relevant energy scales of the correlation, bandwidth,
and most importantly, the strong spin-orbit coupling (SOC). Starting from the
prediction of novel oxide topological insulators in bilayer ABO3 (B = 5d
elements) thin-film grown along the (111) direction, 5d-based perovskites (Pv)
form a new paradigm in the thin-film community. Here, we reviewed the
scientific accomplishments in Pv-SrIrO3 thin films, a popular candidate for
observing non-trivial topological phenomena. Although the predicted topological
phenomena are unknown, the Pv-SrIrO3 thin film shows many emergent properties
due to the delicate interplay between its various degrees of freedom. These
observations provide new physical insight and encourage further research on the
design of new 5d-based heterostructures or superlattices for the observation of
the hidden topological quantum phenomena in strong spin-orbit coupled oxides.


title: Homotopy- and Cohomology Groups of Kan Complexes

abstract:
  This article shows several new methods for proofs on Kan complexes while
using them to give a compact introduction to the homotopy groups of these
complexes. Then more advanced objects are studied starting with homology and
the Hurewicz homomorphism. Eilenberg-Mac Lane-spaces are constructed explicitly
and can then be used to define spectral cohomology. In the end the equivalence
to the usual simplicial cohomology is shown.


title: Locally conformal symplectic blow-ups

abstract:
  In this paper, we study the blow-up of a locally conformal symplectic
manifold.We show that there exists a locally conformal symplectic structure on
the blow-up of a locally conformal symplectic manifold along a compact induced
symplectic submanifold.


title:
Nonparametric Estimation and Testing on Discontinuity of Positive
  Supported Densities: A Kernel Truncation Approach

abstract:
  Discontinuity in density functions is of economic importance and interest.
For instance, in studies on regression discontinuity designs, discontinuity in
the density of a running variable suggests violation of the no-manipulation
assumption. In this paper we develop estimation and testing procedures on
discontinuity in densities with positive support. Our approach is built on
splitting the gamma kernel (Chen, 2000) into two parts at a given
(dis)continuity point and constructing two truncated kernels. The jump-size
magnitude of the density at the point can be estimated nonparametrically by two
kernels and a multiplicative bias correction method. The estimator is easy to
implement, and its convergence properties are delivered by various
approximation techniques on incomplete gamma functions. Based on the jump-size
estimator, two versions of test statistics for the null of continuity at a
given point are also proposed. Moreover, estimation theory of the entire
density in the presence of a discontinuity point is explored. Monte Carlo
simulations confirm nice finite-sample properties of the jump-size estimator
and the test statistics.


title:
Exploiting Temporal Information for DCNN-based Fine-Grained Object
  Classification

abstract:
  Fine-grained classification is a relatively new field that has concentrated
on using information from a single image, while ignoring the enormous potential
of using video data to improve classification. In this work we present the
novel task of video-based fine-grained object classification, propose a
corresponding new video dataset, and perform a systematic study of several
recent deep convolutional neural network (DCNN) based approaches, which we
specifically adapt to the task. We evaluate three-dimensional DCNNs, two-stream
DCNNs, and bilinear DCNNs. Two forms of the two-stream approach are used, where
spatial and temporal data from two independent DCNNs are fused either via early
fusion (combination of the fully-connected layers) and late fusion
(concatenation of the softmax outputs of the DCNNs). For bilinear DCNNs,
information from the convolutional layers of the spatial and temporal DCNNs is
combined via local co-occurrences. We then fuse the bilinear DCNN and early
fusion of the two-stream approach to combine the spatial and temporal
information at the local and global level (Spatio-Temporal Co-occurrence).
Using the new and challenging video dataset of birds, classification
performance is improved from 23.1% (using single images) to 41.1% when using
the Spatio-Temporal Co-occurrence system. Incorporating automatically detected
bounding box location further improves the classification accuracy to 53.6%.


title:
Analysis of Neutron Stars Observations Using a Correlated Fermi Gas
  Model

abstract:
  Background: The nuclear symmetry energy is a fundamental ingredient in
determining the equation of state (EOS) of neutron stars (NS). Recent
terrestrial experiments constrain both its value and slope at nuclear
saturation density, however, its value at higher densities is unknown. Assuming
a Free Fermi-gas (FFG) model for the kinetic symmetry energy, the high-density
extrapolation depends on a single parameter, the density dependence of the
potential symmetry energy. The Correlated Fermi-gas (CFG) model improves on the
FFG model by including the effects of short-range, correlated, high-momentum,
nucleons in nuclear matter. Using the CFG model for the kinetic symmetry energy
along with constraints from terrestrial measurements leads to a much softer
density dependence for the potential symmetry energy. Purpose: Examine the
ability of the FFG and CFG models to describe NS observables that are directly
sensitive to the symmetry energy at high-density. Specifically, examine the
ability of the CFG model, with its softer density dependence of the potential
symmetry energy, to describe a two solar-mass NS. Methods: Using a Bayesian
analysis of NS observables we compare the CFG and FFG models and examine the
resulting parameters in the NS EOS and the density dependence of the potential
symmetry energy. Results: Despite the large difference in the density
dependence of the potential part of the symmetry energy, both models can
describe the NS data and support a two solar-mass NS. The different density
dependences has only a small effect on the NS EOS. Conclusions: While sensitive
to the high-density values of the symmetry energy, NS observables alone are not
enough to distinguish between the CFG and FFG models. This indicates that the
NS EOS, obtain from Bayesian analysis of NS observables, is robust and is not
sensitive to the exact nuclear model used for the kinetic symmetry energy.


title:
Optimal control of treatment time in a diffuse interface model of tumor
  growth

abstract:
  We consider an optimal control problem for a diffuse interface model of tumor
growth. The state equations couples a Cahn-Hilliard equation and a
reaction-diffusion equation, which models the growth of a tumor in the presence
of a nutrient and surrounded by host tissue. The introduction of cytotoxic
drugs into the system serves to eliminate the tumor cells and in this setting
the concentration of the cytotoxic drugs will act as the control variable.
Furthermore, we allow the objective functional to depend on a free time
variable, which represents the unknown treatment time to be optimized. As a
result, we obtain first order necessary optimality conditions for both the
cytotoxic concentration and the treatment time.


title: Buoyancy driven turbulence and distributed chaos

abstract:
  It is shown, using results of recent direct numerical simulations, laboratory
experiments and atmospheric measurements, that buoyancy driven turbulence
exhibits a broad diversity of the types of distributed chaos with its stretched
exponential spectrum $\exp(-k/k_{\beta})^{\beta}$. The distributed chaos with
$\beta = 1/3$ (determined by the helicity correlation integral) is the most
common feature of the stably stratified turbulence (due to the strong helical
waves presence). These waves mostly dominate spectral properties of the
vertical component of velocity field, while the horizontal component is
dominated by the diffusive processes both for the weak and strong stable
stratification ($\beta =2/3$). For the last case influence of the low boundary
can overcome the wave effects and result in $\beta =1/2$ for the vertical
component of the velocity field (the spontaneous breaking of the space
translational symmetry - homogeneity). For the unstably stratified turbulence
in the Rayleigh-Taylor mixing zone the diffusive processes ($\beta =2/3$) are
the most common dominating processes in the anisotropic chaotic mixing of the
two fluids under buoyancy forces. The distributed chaos in Rayleigh-B\'{e}nard
turbulent convection in an upright cell is determined by the strong confinement
conditions. That is: the spontaneous breaking of the space translational
symmetry (homogeneity) by the finite boundaries ($\beta = 1/2$) or by the
non-perfect orientation of the cell along the buoyancy direction ($\beta
=4/7$). In all types of turbulence appearance of an inertial range of scales
results in deformation of the distributed chaos and $\beta =3/5$.


title: On singular equations with critical and supercritical exponents

abstract:
  We study the problem \begin{equation*} (I_{\epsilon}) \left\{\begin{aligned}
  -\Delta u- \frac{\mu u}{|x|^2}&=u^p -\epsilon u^q \quad\text{in }\quad
\Omega, \\ u&>0 \quad\text{in }\quad \Omega, \\ u &\in H^1_0(\Omega)\cap
L^{q+1}(\Omega),
  \end{aligned}
  \right. \end{equation*} where $q>p\geq 2^*-1$, $\epsilon>0$ is a parameter,
$\Omega\subseteq\mathbb{R}^N$ is a bounded domain with smooth boundary, $0\in
\Omega$, $N\geq 3$ and $0<\mu<\bar\mu:=\big(\frac{N-2}{2}\big)^2$. We prove at
$0$, any solution of $(I_{\epsilon})$ has the singularity of order $|x|^{-\nu}$
when $q<\frac{2+\nu}{\nu}$ and of the order $|x|^{-\frac{2}{q-1}}$, when
$q>\frac{2+\nu}{\nu}$, where $\nu=\sqrt{\bar\mu}-\sqrt{\bar\mu-\mu}$. Moreover,
we show that when $q=\frac{2+\nu}{\nu}$ and $u$ is radial, $u\sim
|x|^{-\nu}|\log|x||^{-\frac{\nu}{2}}$. This gives the complete classification
of singularity at $0$ in the supercritical case. We also obtain gradient
estimate. Using the transformation $v=|x|^{\nu}u$, we reduce the problem
$(I_{\epsilon})$ to $(J_{\epsilon})$ \begin{equation*} (J_{\epsilon})
\left\{\begin{aligned}
  -div(|x|^{-2\nu} \nabla v)&=|x|^{-(p+1)\nu} v^p -\epsilon |x|^{-(q+1)\nu} v^q
\quad\text{in }\quad \Omega, \\ v&>0 \quad\text{in }\quad \Omega, \\ v& \in
H^1_0(\Omega, |x|^{-2\nu} )\cap L^{q+1}(\Omega, |x|^{-(q+1)\nu} ),
  \end{aligned}
  \right. \end{equation*} and then formulating a variational problem for
$(J_{\epsilon})$, we establish the existence of a variational solution
$v_{\epsilon}$. Furthermore, we characterize the asymptotic behavior of
$v_{\epsilon}$ as $\epsilon\to 0$ by variational arguments and when $p=2^*-1$,
we show how the solution $v_{\epsilon}$ blows-up at $0$.
  This is the first paper where the results have been established with super
critical exponents for $\mu>0$.


title: Critical gravitational collapse with angular momentum

abstract:
  We derive a theoretical model of mass and angular momentum scaling in type-II
critical collapse with rotation. We focus on the case where the critical
solution has precisely one, spherically symmetric, unstable mode. We
demonstrate excellent agreement with numerical results for critical collapse of
a rotating radiation fluid, which falls into this case.


title:
Some observations on the optimization of a parallel SHAKE function using
  Sakura

abstract:
  Some parallel constructions of a SHAKE hash function using Sakura coding are
introduced, whose basic operation is the Keccak's permutation. For each
proposed tree-based algorithm, observations are made on both its parallel
running time (depth) and the required number of processors to reach it. This
preliminary work makes the assumption that the tree-level chaining value length
is equal to the capacity of the underlying sponge construction, as recommended
in the Sakura paper.


title:
Cosmological constant problem in a scenario with compactifications (RS-I
  model)

abstract:
  In this letter, we apply the Randall-Sundrum (RS) model, a scenario based on
compactifications, to control the UV divergence of the zero-point energy
density equation for the vacuum fluctuations, which has been unsuccessfully
addressed to the cosmological constant (CC) due to a heavy discrepancy between
theory and observation. Historically, the problem of CC has been shelved in the
RS point of view, having few or non literature on the subject. In this sense
and as done with the hierarchy problem, we apply the RS model to solve this
difference via extra dimensions; we also describe how brane effects could be
the solution to this substantial difference. It should be noticed that this
problem is studied assuming first Minkoswki type branes, and then followed by
cosmologically more realistic FLRW type branes. We finally find some remarkably
interesting consequences in the RS scenario: The CC problem can be solved via
compactification of the extra dimension and the compactification radius turns
out to be approximately twice the one used to solve the hierarchy problem in
the $\beta\pi r$ factor by Randall and Sundrum, suggesting that this subtle
difference in both problems could be caused by corrections that comes from
quantum gravity effects. We also estimate the corresponding scale where,
according to this results, we should begin to notice subtle deviations to the
inverse square law of gravitation due to the presence of the extra dimension.


title: Recent results and prospects for NA62 experiment

abstract:
  The $K^+\rightarrow \pi^+ \nu \bar \nu$ decay is theoretically one of the
cleanest meson decays and so a good place to look for indirect effects of new
physics complementary to LHC searches. The NA62 experiment at CERN is designed
to measure the branching ratio of this decay with 10\% precision. NA62 was
commissioned in October 2014, took data in pilot runs in 2014 and 2015. The
NA62 experimental setup is illustrated and data quality is reported.


title: On the Pelczynski conjecture on Auerbach Bases

abstract:
  We consider Auerbach bases in Banach spaces of dimension n>2. We show that
there exists at least (n-1)n/2+1 such bases. This estimate follows from the
calculation of the Lusternik-Schnirelmann category of the flag variety. A
better estimate is obtained for generic Banach spaces by the Morse theory.


title: On Spacetime Transformation Optics: Temporal and Spatial Dispersion

abstract:
  The electromagnetic implementation of cloaking, the hiding of objects from
sight by diverting and reassembling illuminating electromagnetic fields has now
been with us ten years, while the notion of hiding events is now five. Both
schemes as initially presented neglected the inevitable dispersion that arises
when a designed medium replaces vacuum under transformation. Here we define a
transformation design protocol that incorporates both spacetime transformations
and dispersive material responses in a natural and rigorous way. We show how
this methodology is applied to an event cloak designed to appear as a
homogeneous and isotropic but dispersive medium. The consequences for spacetime
transformation design in dispersive materials are discussed, and some parameter
and bandwidth constraints identified.


title: From Weak to Strong LP Gaps for all CSPs

abstract:
  We study the approximability of constraint satisfaction problems (CSPs) by
linear programming (LP) relaxations. We show that for every CSP, the
approximation obtained by a basic LP relaxation, is no weaker than the
approximation obtained using relaxations given by $\Omega\left(\frac{\log
n}{\log \log n}\right)$ levels of the Sherali-Adams hierarchy on instances of
size $n$.
  It was proved by Chan et al. [FOCS 2013] that any polynomial size LP extended
formulation is no stronger than relaxations obtained by a super-constant levels
of the Sherali-Adams hierarchy.. Combining this with our result also implies
that any polynomial size LP extended formulation is no stronger than the basic
LP.
  Using our techniques, we also simplify and strengthen the result by Khot et
al. [STOC 2014] on (strong) approximation resistance for LPs. They provided a
necessary and sufficient condition under which $\Omega(\log \log n)$ levels of
the Sherali-Adams hierarchy cannot achieve an approximation better than a
random assignment. We simplify their proof and strengthen the bound to
$\Omega\left(\frac{\log n}{\log \log n}\right)$ levels.


title:
Perfect state transfer by means of discrete-time quantum walk search
  algorithms on highly symmetric graphs

abstract:
  Perfect state transfer between two marked vertices of a graph by means of
discrete-time quantum walk is analyzed. We consider the quantum walk search
algorithm with two marked vertices, sender and receiver. It is shown by
explicit calculation that for the coined quantum walks on star graph and
complete graph with self-loops perfect state transfer between the sender and
receiver vertex is achieved for arbitrary number of vertices $N$ in
$O(\sqrt{N})$ steps of the walk. Finally, we show that Szegedy's walk with
queries on complete graph allows for state transfer with unit fidelity in the
limit of large $N$.


title: Endotrivial modules for finite groups via homotopy theory

abstract:
  Classifying endotrivial kG-modules, i.e., elements of the Picard group of the
stable module category for an arbitrary finite group G, has been a long-running
quest. By deep work of Dade, Alperin, Carlson, Thevenaz, and others, it has
been reduced to understanding the subgroup consisting of modular
representations that split as the trivial module k direct sum a projective
module when restricted to a Sylow p-subgroup. In this paper we identify this
subgroup as the first cohomology group of the orbit category on non-trivial
p-subgroups with values in the units k^x, viewed as a constant coefficient
system. We then use homotopical techniques to give a number of formulas for
this group in terms of the abelianization of normalizers and centralizers in G,
in particular verifying the Carlson-Thevenaz conjecture--this reduces the
calculation of this group to algorithmic calculations in local group theory
rather than representation theory. We also provide strong restrictions on when
such representations of dimension greater than one can occur, in terms of the
p-subgroup complex and p-fusion systems. We immediately recover and extend a
large number of computational results in the literature, and further illustrate
the computational potential by calculating the group in other sample new cases,
e.g., for the Monster at all primes.


title:
Boundary integral equations for calculating complex eigenvalues of
  transmission problems

abstract:
  Resonance frequencies are complex eigenvalues at which the homogeneous
transmission problems have non-trivial solutions. These frequencies are of
interest because they affect the behavior of the solutions even when the
frequency is real. The resonance frequencies are related to problems for
infinite domains which can be solved efficiently with the Boundary Integral
Equation Method (BIEM). We thus consider a numerical method of determining
resonance frequencies with fast BIEM and the Sakurai-Sugiura projection Method
(SSM). However, BIEM may have fictitious eigenvalues even when one uses
M\"uller or PMCHWT formulations which are known to be resonance free when the
frequency is real valued.
  In this paper, we propose new BIEs for transmission problems with which one
can distinguish true and fictitious eigenvalues easily. Specifically, we
consider waveguide problems for the Helmholtz equation in 2D and standard
scattering problems for Maxwell's equations in 3D. We verify numerically that
the proposed BIEs can separate the fictitious eigenvalues from the true ones in
these problems. We show that the obtained true complex eigenvalues are related
to the behavior of the solution significantly. We also show that the fictitious
eigenvalues may affect the accuracy of BIE solutions in standard boundary value
problems even when the frequency is real.


title:
Supervised Classification of RADARSAT-2 Polarimetric Data for Different
  Land Features

abstract:
  The pixel percentage belonging to the user defined area that are assigned to
cluster in a confusion matrix for RADARSAT-2 over Vancouver area has been
analysed for classification. In this study, supervised Wishart and Support
Vector Machine (SVM) classifiers over RADARSAT-2 (RS2) fine quadpol mode Single
Look Complex (SLC) product data is computed and compared. In comparison with
conventional single channel or dual channel polarization, RADARSAT-2 is fully
polarimetric, making it to offer better land feature contrast for
classification operation.


title:
Absorption spectroscopy of xenon and ethylene-noble gas mixtures at high
  pressure: Towards Bose-Einstein condensation of vacuum ultraviolet photons

abstract:
  Bose-Einstein condensation is a phenomenon well known for material particles
as cold atomic gases, and this concept has in recent years been extended to
photons confined in microscopic optical cavities. Essential for the operation
of such a photon condensate is a thermalization mechanism that conserves the
average particle number, as in the visible spectral regime can be realized by
subsequent absorption re-emission processes in dye molecules. Here we report on
the status of an experimental effort aiming at the extension of the concept of
Bose-Einstein condensation of photons towards the vacuum ultraviolet spectral
regime, with gases at high pressure conditions serving as a thermalization
medium for the photon gas. We have recorded absorption spectra of xenon gas at
up to 30 bar gas pressure of the $5p^6 - 5p^56s$ transition with a wavelength
close to 147 nm. Moreover, spectra of ethylene noble gas mixtures between 155
and 180 nm wavelength are reported.


title: Atomic Collapse in Graphene: Lost of Unitarity

abstract:
  We explore the problem of atomic collapse in graphene by monopole impurities,
both electric and magnetic, within the context of supersymmetric quantum
mechanics. For electric impurities, upon factorizing the radial Dirac
Hamiltonian and identifying the supercharges, existence of a critical charge
that makes the ground state {\em fall-into-the-center} translates into lost of
hermicity for the corresponding Hamiltonian and hence lost of unitarity of the
theory. For the problem of magnetic monopole impurities, preservation of
unitarity for all values of the parameters of the corresponding potential
translates into the absence of atomic collapse in this case.

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


title: Double quantum dot Cooper-pair splitter at finite couplings

abstract:
  We consider the sub-gap physics of a hybrid double-quantum dot Cooper-pair
splitter with large single-level spacings, in the presence of tunnelling
between the dots and finite Coulomb intra- and inter-dot Coulomb repulsion. In
the limit of a large superconducting gap, we treat the coupling of the dots to
the superconductor exactly. We employ a generalized master-equation method
which easily yields currents, noise and cross-correlators. In particular, for
finite inter- and intra-dot Coulomb interaction, we investigate how the
transport properties are determined by the interplay between local and nonlocal
tunneling processes between the superconductor and the dots. We examine the
effect of inter-dot tunneling on the particle-hole symmetry of the currents
with and without spin-orbit interaction. We show that spin-orbit interaction in
combination with finite Coulomb energy opens the possibility to control the
nonlocal entanglement and its symmetry (singlet/triplet). We demonstrate that
the generation of nonlocal entanglement can be achieved even without any direct
nonlocal coupling to the superconducting lead.


title: Where does a random process hit a fractal barrier?

abstract:
  Given a Brownian path $\beta(t)$ on $\mathbb{R}$, starting at $1$, a.s. there
is a singular time set $T_{\beta}$, such that the first hitting time of $\beta$
by an independent Brownian motion, starting at $0$, is in $T_{\beta}$ with
probability one. A couple of problems regarding hitting measure for random
processes are presented.


title:
Spin relaxation and the Kondo effect in transition metal dichalcogenide
  monolayers

abstract:
  We investigate the spin relaxation and Kondo resistivity caused by magnetic
impurities in doped transition metal dichalcogenides monolayers. We show that
momentum and spin relaxation times due to the exchange interaction by magnetic
impurities, are much longer when the Fermi level is inside the spin split
region of the valence band. In contrast to the spin relaxation, we find that
the dependence of Kondo temperature $T_K$ on the doping is not strongly
affected by the spin-orbit induced splitting, although only one of the spin
species are present at each valley. This result, which is obtained using both
perturbation theory and poor man's scaling methods, originates from the
intervalley spin-flip scattering in the spin-split region. We further
demonstrate the decline in the conductivity with temperatures close to $T_K$
which can vary with the doping. Our findings reveal the qualitative difference
with the Kondo physics in conventional metallic systems and other Dirac
materials.


title: Top-down Neural Attention by Excitation Backprop

abstract:
  We aim to model the top-down attention of a Convolutional Neural Network
(CNN) classifier for generating task-specific attention maps. Inspired by a
top-down human visual attention model, we propose a new backpropagation scheme,
called Excitation Backprop, to pass along top-down signals downwards in the
network hierarchy via a probabilistic Winner-Take-All process. Furthermore, we
introduce the concept of contrastive attention to make the top-down attention
maps more discriminative. In experiments, we demonstrate the accuracy and
generalizability of our method in weakly supervised localization tasks on the
MS COCO, PASCAL VOC07 and ImageNet datasets. The usefulness of our method is
further validated in the text-to-region association task. On the Flickr30k
Entities dataset, we achieve promising performance in phrase localization by
leveraging the top-down attention of a CNN model that has been trained on
weakly labeled web images.


title: Blind phoneme segmentation with temporal prediction errors

abstract:
  Phonemic segmentation of speech is a critical step of speech recognition
systems. We propose a novel unsupervised algorithm based on sequence prediction
models such as Markov chains and recurrent neural network. Our approach
consists in analyzing the error profile of a model trained to predict speech
features frame-by-frame. Specifically, we try to learn the dynamics of speech
in the MFCC space and hypothesize boundaries from local maxima in the
prediction error. We evaluate our system on the TIMIT dataset, with
improvements over similar methods.


title: TorBricks: Blocking-Resistant Tor Bridge Distribution

abstract:
  Tor is currently the most popular network for anonymous Internet access. It
critically relies on volunteer nodes called bridges for relaying Internet
traffic when a user's ISP blocks connections to Tor. Unfortunately, current
methods for distributing bridges are vulnerable to malicious users who obtain
and block bridge addresses. In this paper, we propose TorBricks, a protocol for
distributing Tor bridges to n users, even when an unknown number t < n of these
users are controlled by a malicious adversary. TorBricks distributes O(tlog(n))
bridges and guarantees that all honest users can connect to Tor with high
probability after O(log(t)) rounds of communication with the distributor.
  We also extend our algorithm to perform privacy-preserving bridge
distribution when run among multiple untrusted distributors. This not only
prevents the distributors from learning bridge addresses and bridge assignment
information, but also provides resistance against malicious attacks from a m/3
fraction of the distributors, where m is the number of distributors.


title: Lifting of elements of Weyl groups

abstract:
  Suppose $G$ is a reductive algebraic group, $T$ is a Cartan subgroup,
$N=\text{Norm}(T)$, and $W=N/T$ is the Weyl group. If $w\in W$ has order $d$,
it is natural to ask about the orders lifts of $w$ to $N$. It is
straightforward to see that the minimal order of a lift of $w$ has order $d$ or
$2d$, but it can be a subtle question which holds. We first consider the
question of when $W$ itself lifts to a subgroup of $N$ (in which case every
element of $W$ lifts to an element of $N$ of the same order). We then consider
two natural classes of elements: regular and elliptic. In the latter case all
lifts of $w$ are conjugate, and therefore have the same order. We also consider
the twisted case.


title:
On Finite difference schemes for partial integro-differential equations
  of L\'evy type

abstract:
  In this article we introduce a finite difference approximation for
integro-differential operators of L\'evy type. We approximate solutions of
integro-differential equations, where the second order operator is allowed to
degenerate. In the existing literature, the L\'evy operator is treated as a
zero/first order operator outside of a centered ball of radius $\delta$,
leading to error estimates of order $\xi (\delta)+N(\delta)(h+\sqrt{\tau})$,
where $h$ and $\tau$ are the spatial and temporal discretization parameters
respectively. In these estimates $\xi (\delta) \downarrow 0$, but $N(\delta
)\uparrow \infty$ as $\delta \downarrow 0$. In contrast, we treat the
integro-differential operator as a second order operator on the whole unit
ball. By this method we obtain error estimates of order $(h+\tau^k)$ for $k\in
\{1/2,1\}$, eliminating the additional errors and the blowing up constants.
Moreover, we do not pose any conditions on the L\'evy measure.


title: Optimal weighted least-squares methods

abstract:
  We consider the problem of reconstructing an unknown bounded function $u$
defined on a domain $X\subset \mathbb{R}^d$ from noiseless or noisy samples of
$u$ at $n$ points $(x^i)_{i=1,\dots,n}$. We measure the reconstruction error in
a norm $L^2(X,d\rho)$ for some given probability measure $d\rho$. Given a
linear space $V_m$ with ${\rm dim}(V_m)=m\leq n$, we study in general terms the
weighted least-squares approximations from the spaces $V_m$ based on
independent random samples. The contribution of the present paper is twofold.
From the theoretical perspective, we establish results in expectation and in
probability for weighted least squares in general approximation spaces $V_m$.
These results show that for an optimal choice of sampling measure $d\mu$ and
weight $w$, which depends on the space $V_m$ and on the measure $d\rho$,
stability and optimal accuracy are achieved under the mild condition that $n$
scales linearly with $m$ up to an additional logarithmic factor. The present
analysis covers also cases where the function $u$ and its approximants from
$V_m$ are unbounded, which might occur for instance in the relevant case where
$X=\mathbb{R}^d$ and $d\rho$ is the Gaussian measure. From the numerical
perspective, we propose a sampling method which allows one to generate
independent and identically distributed samples from the optimal measure
$d\mu$. This method becomes of interest in the multivariate setting where
$d\mu$ is generally not of tensor product type. We illustrate this for
particular examples of approximation spaces $V_m$ of polynomial type, where the
domain $X$ is allowed to be unbounded and high or even infinite dimensional,
motivated by certain applications to parametric and stochastic PDEs.


title: Magnetic fields of opposite polarity in sunspot penumbrae

abstract:
  Context. A significant part of the penumbral magnetic field returns below the
surface in the very deep photosphere. For lines in the visible, a large portion
of this return field can only be detected indirectly by studying its imprints
on strongly asymmetric and three-lobed Stokes V profiles. Infrared lines probe
a narrow layer in the very deep photosphere, providing the possibility of
directly measuring the orientation of magnetic fields close to the solar
surface.
  Aims. We study the topology of the penumbral magnetic field in the lower
photosphere, focusing on regions where it returns below the surface.
  Methods. We analyzed 71 spectropolarimetric datasets from Hinode and from the
GREGOR infrared spectrograph. We inferred the quality and polarimetric accuracy
of the infrared data after applying several reduction steps. Techniques of
spectral inversion and forward synthesis were used to test the detection
algorithm. We compared the morphology and the fractional penumbral area covered
by reversed-polarity and three-lobed Stokes V profiles for sunspots at disk
center. We determined the amount of reversed-polarity and three-lobed Stokes V
profiles in visible and infrared data of sunspots at various heliocentric
angles. From the results, we computed center-to-limb variation curves, which
were interpreted in the context of existing penumbral models.
  Results. Observations in visible and near-infrared spectral lines yield a
significant difference in the penumbral area covered by magnetic fields of
opposite polarity. In the infrared, the number of reversed-polarity Stokes V
profiles is smaller by a factor of two than in the visible. For three-lobed
Stokes V profiles the numbers differ by up to an order of magnitude.


title:
Dimensionality reduction based on Distance Preservation to Local Mean
  (DPLM) for SPD matrices and its application in BCI

abstract:
  In this paper, we propose a nonlinear dimensionality reduction algorithm for
the manifold of Symmetric Positive Definite (SPD) matrices that considers the
geometry of SPD matrices and provides a low dimensional representation of the
manifold with high class discrimination. The proposed algorithm, tries to
preserve the local structure of the data by preserving distance to local mean
(DPLM) and also provides an implicit projection matrix. DPLM is linear in terms
of the number of training samples and may use the label information when they
are available in order to performance improvement in classification tasks. We
performed several experiments on the multi-class dataset IIa from BCI
competition IV. The results show that our approach as dimensionality reduction
technique - leads to superior results in comparison with other competitor in
the related literature because of its robustness against outliers. The
experiments confirm that the combination of DPLM with FGMDM as the classifier
leads to the state of the art performance on this dataset.


title: Mixed-Dimensional van der Waals Heterostructures

abstract:
  The isolation of a growing number of two-dimensional (2D) materials has
inspired worldwide efforts to integrate distinct 2D materials into van der
Waals (vdW) heterostructures. Given that any passivated, dangling bond-free
surface will interact with another via vdW forces, the vdW heterostructure
concept can be extended to include the integration of 2D materials with non-2D
materials that adhere primarily through noncovalent interactions. In this
review, we present a succinct and critical survey of emerging mixed-dimensional
(2D + nD, where n is 0, 1 or 3) heterostructure devices. By comparing and
contrasting with all-2D vdW heterostructures as well as with competing
conventional technologies, the challenges and opportunities for
mixed-dimensional vdW heterostructures are highlighted.


title:
Theory of substrate-directed heat dissipation for single-layer graphene
  and other two-dimensional crystals

abstract:
  We present a theory of the phononic thermal (Kapitza) resistance at the
interface between graphene or another single-layer two-dimensional (2D) crystal
(e.g. MoS$_{2}$) and a flat substrate, based on a modified version of the
cross-plane heat transfer model by Persson, Volokitin and Ueba [J. Phys.:
Condens. Matter 23, 045009 (2011)]. We show how intrinsic flexural phonon
damping is necessary for obtaining a finite Kapitza resistance and also
generalize the theory to encased single-layer 2D crystals with a superstrate.
We illustrate our model by computing the thermal boundary conductance (TBC) for
bare and SiO$_{2}$-encased single-layer graphene and MoS$_{2}$ on a SiO$_{2}$
substrate, using input parameters from first-principles calculation. The
estimated room temperature TBC for bare (encased) graphene and MoS$_{2}$ on
SiO$_{2}$ are 34.6 (105) and 3.10 (5.07) MWK$^{-1}$m$^{-2}$, respectively. The
theory predicts the existence of a phonon frequency crossover point, below
which the low-frequency flexural phonons in the bare 2D crystal do not
dissipate energy efficiently to the substrate. We explain within the framework
of our theory how the encasement of graphene with a top SiO$_{2}$ layer
introduces new low-frequency transmission channels which significantly reduce
the graphene-substrate Kapitza resistance. We emphasize that the distinction
between bare and encased 2D crystals must be made in the analysis of
cross-plane heat dissipation to the substrate.


title:
The width of the $\Delta$-resonance at two loop order in baryon chiral
  perturbation theory

abstract:
  We calculate the width of the delta resonance at leading two-loop order in
baryon chiral perturbation theory. This gives a correlation between the leading
pion-nucleon-delta and pion-delta couplings, which is relevant for the analysis
of pion-nucleon scattering and other processes.


title: Supercompact Extender Based Magidor-Radin Forcing

abstract:
  The extender based Magidor-Radin forcing is being generalized to supercompact
type extenders.


title: Theorems for Asymptotic Safety of Gauge Theories

abstract:
  We classify the weakly interacting fixed points of general gauge theories
coupled to matter and explain how the competition between gauge and matter
fluctuations gives rise to a rich spectrum of high- and low-energy fixed
points. The pivotal role played by Yukawa couplings is emphasized. Necessary
and sufficient conditions for asymptotic safety of gauge theories are also
derived, in conjunction with strict no go theorems. Implications for phase
diagrams of gauge theories and physics beyond the Standard Model are indicated.


title: Quantum graphs which optimize the spectral gap

abstract:
  A finite discrete graph is turned into a quantum (metric) graph once a finite
length is assigned to each edge and the one-dimensional Laplacian is taken to
be the operator. We study the dependence of the spectral gap (the first
positive Laplacian eigenvalue) on the choice of edge lengths. In particular,
starting from a certain discrete graph, we seek the quantum graph for which an
optimal (either maximal or minimal) spectral gap is obtained. We fully solve
the minimization problem for all graphs. We develop tools for investigating the
maximization problem and solve it for some families of graphs.


title: A topological characterization of toroidally alternating knots

abstract:
  We extend Howie's characterization of alternating knots to give a topological
characterization of toroidally alternating knots, which were defined by Adams.
We provide necessary and sufficient conditions for a knot to be toroidally
alternating. We also give a topological characterization of almost-alternating
knots which is different from Ito's recent characterization.


title: A parametrisation of modified gravity on nonlinear cosmological scales

abstract:
  Viable modifications of gravity on cosmological scales predominantly rely on
screening mechanisms to recover Einstein's Theory of General Relativity in the
Solar System, where it has been well tested. A parametrisation of the effects
of such modifications in the spherical collapse model is presented here for the
use of modelling the modified nonlinear cosmological structure. The formalism
allows an embedding of the different screening mechanisms operating in
scalar-tensor theories through large values of the gravitational potential or
its first or second derivatives as well as of linear suppression effects or
more general transitions between modified and Einstein gravity limits. Each
screening or suppression mechanism is parametrised by a time, mass, and
environment dependent screening scale, an effective modified gravitational
coupling in the fully unscreened limit that can be matched to linear theory,
the exponent of a power-law radial profile of the screened coupling, determined
by derivatives, symmetries, and potentials in the scalar field equation, and an
interpolation rate between the screened and unscreened limits. Along with
generalised perturbative methods, the parametrisation may be used to formulate
a nonlinear extension to the linear parametrised post-Friedmannian framework to
enable generalised tests of gravity with the wealth of observations from the
nonlinear cosmological regime.


title: Exploring minijets beyond the leading power

abstract:
  The crucial parameter of the current Monte Carlo models of high energy
hadron-hadron interaction is the transverse momentum cutoff $p_{T0}$ for
parton-parton interactions which slowly grows with energy and regularizes the
cross section. This modification of the collinear factorization formula goes
beyond the leading power and thus a natural question arises if such cutoff can
be extracted from a formalism which takes into account power corrections. In
this work, we consider the High Energy Factorization (HEF) valid at small $x$
and a new model, based on a similar principle to HEF, which in addition has a
limit respecting the Dokshitzer-Dyakonov-Troyan formula for the dijet momentum
disbalance spectrum. Minijet cross section and its suppression is then analyzed
in two ways. First, we study minijets directly in the low-$p_T$ region, and
demonstrate that higher twist corrections do generate suppression of the
inclusive jet production cross section though these effects are not leading to
the increase of the cutoff with incident energy. Second, we consider hard
inclusive dijet production where Multi Parton Interactions (MPIs) with minijets
produce power corrections. We introduce an observable constructed from
differential cross section in the ratio $\tau$ of dijet disbalance to the
average dijet $p_T$ and demonstrate that the $\tau>1$ region is sensitive to
the cutoff $p_{T0}$ in the MPI minijet models. The energy dependence of the
cutoff is reflected in the energy dependence of the bimodality coefficient $b$
of the $\tau$ distribution. We compare $b$ calculated from $\mathsf{pythia}$,
where one can conveniently control MPIs by the program parameters, and HEF for
a few unintegrated gluon distributions (UGDs). We find that the energy
dependence of $b$ is very sensitive to the particular choice of UGD and in some
models it resembles predictions of the Monte Carlo models.


title: Change Detection via Affine and Quadratic Detectors

abstract:
  The goal of the paper is to develop a specific application of the convex
optimization based hypothesis testing techniques developed in A. Juditsky, A.
Nemirovski, "Hypothesis testing via affine detectors," Electronic Journal of
Statistics 10:2204--2242, 2016. Namely, we consider the Change Detection
problem as follows: given an evolving in time noisy observations of outputs of
a discrete-time linear dynamical system, we intend to decide, in a sequential
fashion, on the null hypothesis stating that the input to the system is a
nuisance, vs. the alternative stating that the input is a "nontrivial signal,"
with both the nuisances and the nontrivial signals modeled as inputs belonging
to finite unions of some given convex sets. Assuming the observation noises
zero mean sub-Gaussian, we develop "computation-friendly" sequential decision
rules and demonstrate that in our context these rules are provably
near-optimal.


title: Modeling Context Between Objects for Referring Expression Understanding

abstract:
  Referring expressions usually describe an object using properties of the
object and relationships of the object with other objects. We propose a
technique that integrates context between objects to understand referring
expressions. Our approach uses an LSTM to learn the probability of a referring
expression, with input features from a region and a context region. The context
regions are discovered using multiple-instance learning (MIL) since annotations
for context objects are generally not available for training. We utilize
max-margin based MIL objective functions for training the LSTM. Experiments on
the Google RefExp and UNC RefExp datasets show that modeling context between
objects provides better performance than modeling only object properties. We
also qualitatively show that our technique can ground a referring expression to
its referred region along with the supporting context region.


title: Flavor Universal Resonances and Warped Gravity

abstract:
  Warped higher-dimensional compactifications with "bulk" standard model, or
their AdS/CFT dual as the purely 4D scenario of Higgs compositeness and partial
compositeness, offer an elegant approach to resolving the electroweak hierarchy
problem as well as the origins of flavor structure. However, low-energy
electroweak/flavor/CP constraints and the absence of non-standard physics at
LHC Run 1 suggest that a "little hierarchy problem" remains, and that the new
physics underlying naturalness may lie out of LHC reach. Assuming this to be
the case, we show that there is a simple and natural extension of the minimal
warped model in the Randall-Sundrum framework, in which matter, gauge and
gravitational fields propagate modestly different degrees into the IR of the
warped dimension, resulting in rich and striking consequences for the LHC (and
beyond). The LHC-accessible part of the new physics is AdS/CFT dual to the
mechanism of "vectorlike confinement", with TeV-scale Kaluza-Klein excitations
of the gauge and gravitational fields dual to spin-0,1,2 composites. Unlike the
minimal warped model, these low-lying excitations have predominantly
flavor-blind and flavor/CP-safe interactions with the standard model.
Remarkably, this scenario also predicts small deviations from flavor-blindness
originating from virtual effects of Higgs/top compositeness at $\sim O(10)$
TeV, with subdominant resonance decays into Higgs/top-rich final states, giving
the LHC an early "preview" of the nature of the resolution of the hierarchy
problem. Discoveries of this type at LHC Run 2 would thereby anticipate (and
set a target for) even more explicit explorations of Higgs compositeness at a
100 TeV collider, or for next-generation flavor tests.


title:
Life after eruption - VI. Recovery of the old novae EL Aql, V606 Aql,
  V908 Oph, V1149 Sgr, V1583 Sgr and V3964 Sgr

abstract:
  We report on the recovery of the six old novae EL Aql, V606 Aql, V908 Oph,
V1149 Sgr, V1583 Sgr and V3964 Sgr, using photometric and spectroscopic data.
Analysing several properties, we find that EL Aql is a good candidate for an
intermediate polar. Furthermore, the system inclination of EL Aql, V606 Aql,
V1583 Sgr and V3964 Sgr appears to be sufficiently high to suggest them as good
targets for time series observations. We also eliminate some previously
suggested candidates for the post-novae V1301 Aql and V1151 Sgr.


title: Impartial Predictive Modeling and the Use of Proxy Variables

abstract:
  Fairness aware data mining (FADM) aims to prevent algorithms from
discriminating against protected groups. The literature has come to an impasse
as to what constitutes explainable variability as opposed to discrimination.
This distinction hinges on a rigorous understanding of the role of proxy
variables; i.e., those variables which are associated both the protected
feature and the outcome of interest. We demonstrate that fairness is achieved
by ensuring impartiality with respect to sensitive characteristics and provide
a framework for impartiality by accounting for different perspectives on the
data generating process. In particular, fairness can only be precisely defined
in a full-data scenario in which all covariates are observed. We then analyze
how these models may be conservatively estimated via regression in partial-data
settings. Decomposing the regression estimates provides insights into
previously unexplored distinctions between explainable variability and
discrimination that illuminate the use of proxy variables in fairness aware
data mining.