title:
Cosmological particle-in-cell simulations with ultralight axion dark
  matter

abstract:
  We study cosmological structure formation with ultralight axion dark matter,
or "fuzzy dark matter (FDM), using a particle-mesh scheme to account for the
quantum pressure arising in the Madelung formulation of the
Schr\"odinger-Poisson equations. Subpercent-level energy conservation and
correct linear behavior are demonstrated. Whereas the code gives rise to the
same core-halo profiles as direct simulations of the Schr\"odinger equation, it
does not reproduce the detailed interference patterns. In cosmological
simulations with FDM initial conditions, we find a maximum relative difference
of O($10\%$) in the power spectrum near the quantum Jeans length compared to
using a standard N-body code with identical initial conditions. This shows that
the effect of quantum pressure during nonlinear structure formation cannot be
neglected for precision constraints on a dark matter component consisting of
ultralight axions.


title: On the Ohno-Nakagawa Theorem

abstract:
  In this paper we give a new proof of the Ohno-Nakagawa Theorem using the
techniques of $L$-series. By applying Eisenstein's parametrization of binary
cubic forms on the one hand, and a class field theory interpretation of
Datskovsky \& Wright's Theorem on the other, we reduce the Ohno-Nakagawa
Theorem to an identity involving the $L$-series and the truncated $L$-series of
quadratic orders. We prove this identity by establishing a general relation
among these two types $L$-series.


title:
Dispersive coupling between light and a rare-earth ion doped mechanical
  resonator

abstract:
  By spectrally hole burning an inhomogeneously broadened ensemble of ions
while applying a controlled perturbation, one can obtain spectral holes that
are functionalized for maximum sensitivity to different perturbations. We
propose to use such hole burnt structures for the dispersive optical
interaction with rare-earth ion dopants whose frequencies are sensitive to
crystal strain due to the bending motion of a crystal cantilever. A
quantitative analysis shows that good optical sensitivity to the bending motion
is obtained if a magnetic field gradient is applied across the crystal during
hole burning, and that the resulting opto-mechanical coupling strength is
sufficient for observing quantum features such as zero point vibrations.


title: Starbursts and dusty tori in distant 3CR radio galaxies

abstract:
  We present a study of the complete ultraviolet to submillimetre spectral
energy distributions (SEDs) of twelve 3CR radio galaxy hosts in the redshift
range $1.0 < z < 2.5$, which were all detected in the far-infrared by the
Herschel Space Observatory. The study employs the new spectro-chemical
evolutionary code P\'EGASE.3, in combination with recently published clumpy AGN
torus models. We uncover the properties of the massive host galaxy stellar
populations, the AGN torus luminosities, and the properties of the recent
starbursts, which had earlier been inferred in these objects from their
infrared SEDs. The P\'EGASE.3 fitting yields very luminous (up to
10$^{13}$L$_{\odot}$) young stellar populations with ages of several hundred
million years in hosts with masses exceeding 10$^{11}$M$_{\odot}$. Dust masses
are seen to increase with redshift, and a surprising correlation -- or better
upper envelope behaviour -- is found between the AGN torus luminosity and the
starburst luminosity, as revealed by their associated dust components. The
latter consistently exceeds the former by a constant factor, over a range of
one order of magnitude in both quantities.


title: Secure Communications in Millimeter Wave Ad Hoc Networks

abstract:
  Wireless networks with directional antennas, like millimeter wave (mmWave)
networks, have enhanced security. For a large-scale mmWave ad hoc network in
which eavesdroppers are randomly located, however, eavesdroppers can still
intercept the confidential messages, since they may reside in the signal beam.
This paper explores the potential of physical layer security in mmWave ad hoc
networks. Specifically, we characterize the impact of mmWave channel
characteristics, random blockages, and antenna gains on the secrecy
performance. For the special case of uniform linear array (ULA), a tractable
approach is proposed to evaluate the average achievable secrecy rate. We also
characterize the impact of artificial noise in such networks. Our results
reveal that in the low transmit powerregime, the use of low mmWave frequency
achieves better secrecy performance, and when increasing transmit power, a
transition from low mmWave frequency to high mmWave frequency is demanded for
obtaining a higher secrecy rate. More antennas at the transmitting nodes are
needed to decrease the antenna gain obtained by the eavesdroppers when using
ULA. Eavesdroppers can intercept more information by using a wide beam pattern.
Furthermore, the use of artificial noise may be ineffective for enhancing the
secrecy rate.


title: Enhanced granular medium-based tube press hardening

abstract:
  Active and passive control strategies of internal pressure for hot forming of
tubes and profiles with granular media are described. Force transmission and
plastic deformation of granular medium is experimentally investigated. Friction
between tube, granular medium and die as also the external stress field are
shown to be essential for the process understanding. Wrinkling, thinning and
insufficient forming of the tube establishes the process window for the active
pressure process. By improving the punch geometry and controlling tribological
conditions, the process limits are extended. Examples for the passive pressure
process reveal new opportunities for hot forming of tubes and profiles.


title:
Topologically protected colloidal transport above a square magnetic
  lattice

abstract:
  We theoretically study the motion of magnetic colloidal particles above a
magnetic pattern and compare the predictions with Brownian dynamics
simulations. The pattern consists of alternating square domains of positive and
negative magnetization. The colloidal motion is driven by periodic modulation
loops of an external magnetic field. There exist loops that induce
topologically protected colloidal transport between two different unit cells of
the pattern. The transport is very robust against internal and external
perturbations. Theory and simulations are in perfect agreement.


title:
XUV-initiated high harmonic generation: driving inner valence electrons
  using below-threshold-energy XUV light

abstract:
  We propose a novel scheme for resolving the contribution of inner- and
outer-valence electrons in XUV-initiated high-harmonic generation in neon. By
probing the atom with a low energy (below the 2s ionisation threshold)
ultrashort XUV pulse, the 2p electron is steered away from the core, while the
2s electron is enabled to describe recollision trajectories. By selectively
suppressing the 2p recollision trajectories we can resolve the contribution of
the 2s electron to the high-harmonic spectrum. We apply the classical
trajectory model to account for the contribution of the 2s electron, which
allows for an intuitive understanding of the process.


title: Directed expected utility networks

abstract:
  A variety of statistical graphical models have been defined to represent the
conditional independences underlying a random vector of interest. Similarly,
many different graphs embedding various types of preferential independences, as
for example conditional utility independence and generalized additive
independence, have more recently started to appear. In this paper we define a
new graphical model, called a directed expected utility network, whose edges
depict both probabilistic and utility conditional independences. These embed a
very flexible class of utility models, much larger than those usually conceived
in standard influence diagrams. Our graphical representation, and various
transformations of the original graph into a tree structure, are then used to
guide fast routines for the computation of a decision problem's expected
utilities. We show that our routines generalize those usually utilized in
standard influence diagrams' evaluations under much more restrictive
conditions. We then proceed with the construction of a directed expected
utility network to support decision makers in the domain of household food
security.


title: Analytical solutions for problems of bubble dynamics

abstract:
  Recently, an asymptotic solution of the Rayleigh equation for an empty bubble
in $N$ dimensions has been obtained. Here we give the closed--from general
analytical solution of this equation. We also find the general solution of the
Rayleigh equation in $N$ dimensions for the case of a gas--filled
hyperspherical bubble. In addition, we include a surface tension into
consideration.


title:
Bismuthene on a SiC Substrate: A Candidate for a New High-Temperature
  Quantum Spin Hall Paradigm

abstract:
  Quantum spin Hall (QSH) materials promise revolutionary device applications
based on dissipationless propagation of spin currents. They are two-dimensional
(2D) representatives of the family of topological insulators, which exhibit
conduction channels at their edges inherently protected against scattering.
Initially predicted for graphene, and eventually realized in HgTe quantum
wells, in the QSH systems realized so far, the decisive bottleneck preventing
applications is the small bulk energy gap of less than 30 meV, requiring
cryogenic operation temperatures in order to suppress detrimental bulk
contributions to the edge conductance. Room-temperature functionalities,
however, require much larger gaps. Here we show how this can be achieved by
making use of a new QSH paradigm based on substrate-supported atomic monolayers
of a high-Z element. Experimentally, the material is synthesized as honeycomb
lattice of bismuth atoms, forming "bismuthene", on top of the wide-gap
substrate SiC(0001). Consistent with the theoretical expectations, the
spectroscopic signatures in experiment display a huge gap of ~0.8 eV in
bismuthene, as well as conductive edge states. The analysis of the
layer-substrate orbitals arrives at a QSH phase, whose topological gap - as a
hallmark mechanism - is driven directly by the atomic spin-orbit coupling
(SOC). Our results demonstrate how strained artificial lattices of heavy atoms,
in contact with an insulating substrate, can be utilized to evoke a novel
topological wide-gap scenario, where the chemical potential is located well
within the global system gap, ensuring pure edge state conductance. We
anticipate future experiments on topological signatures, such as transport
measurements that probe the QSH effect via quantized universal conductance,
notably at room temperature.

categories: cond-mat.str-el cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.supr-con quant-ph


title: Aggregating Binary Local Descriptors for Image Retrieval

abstract:
  Content-Based Image Retrieval based on local features is computationally
expensive because of the complexity of both extraction and matching of local
feature. On one hand, the cost for extracting, representing, and comparing
local visual descriptors has been dramatically reduced by recently proposed
binary local features. On the other hand, aggregation techniques provide a
meaningful summarization of all the extracted feature of an image into a single
descriptor, allowing us to speed up and scale up the image search. Only a few
works have recently mixed together these two research directions, defining
aggregation methods for binary local features, in order to leverage on the
advantage of both approaches. In this paper, we report an extensive comparison
among state-of-the-art aggregation methods applied to binary features. Then, we
mathematically formalize the application of Fisher Kernels to Bernoulli Mixture
Models. Finally, we investigate the combination of the aggregated binary
features with the emerging Convolutional Neural Network (CNN) features. Our
results show that aggregation methods on binary features are effective and
represent a worthwhile alternative to the direct matching. Moreover, the
combination of the CNN with the Fisher Vector (FV) built upon binary features
allowed us to obtain a relative improvement over the CNN results that is in
line with that recently obtained using the combination of the CNN with the FV
built upon SIFTs. The advantage of using the FV built upon binary features is
that the extraction process of binary features is about two order of magnitude
faster than SIFTs.


title: SPDE limit of the global fluctuations in rank-based models

abstract:
  We consider systems of diffusion processes ("particles") interacting through
their ranks (also referred to as "rank-based models" in the mathematical
finance literature). We show that, as the number of particles becomes large,
the process of fluctuations of the empirical cumulative distribution functions
converges to the solution of a linear parabolic SPDE with additive noise. The
coefficients in the limiting SPDE are determined by the hydrodynamic limit of
the particle system which, in turn, can be described by the porous medium PDE.
The result opens the door to a thorough investigation of large equity markets
and investment therein. In the course of the proof we also derive quantitative
propagation of chaos estimates for the particle system.


title: Covariant theory of gravitation in the framework of special relativity

abstract:
  In this work, we study the magnetic effects of gravity in the framework of
special relativity. Imposing covariance of the gravitational force with respect
to the Lorentz transformations, we show from a thought experiment that a
magnetic-like force must be present whenever two or more bodies are in motion.
The exact expression for this gravitomagnetic force is then derived purely from
special relativity and the consequences of such a covariant theory are
developed. For instance, we show that the gravitomagnetic fields satisfy a
system of differential equations similar to the Maxwell equations of
electrodynamics. This implies that the gravitational waves spread out with the
speed of light in a flat spacetime, which is in agreement with the recent
results concerning the gravitational waves detection. We also propose that the
vector potential can be associated with the interaction momentum in the same
way as the scalar potential is usually associated with the interaction energy.
Other topics are also discussed, for example, the transformation laws for the
fields, the energy and momentum stored in the gravitomagnetic fields, the
invariance of the gravitational mass and so on. We remark that is not our
intention here to propose an alternative theory of gravitation but, rather,
only a first approximation for the gravitational phenomena, so that it can be
applied whenever the gravitational force can be regarded as an ordinary
effective force field and special relativity can be used with safety. To make
this point clear we present briefly a comparison between our approach and that
based on the (linearized) Einstein's theory. Finally, we remark that although
we have assumed nothing from the electromagnetic theory, we found that gravity
and electricity share many properties in common - these similarities, in fact,
are just a requirement of special relativity that must apply to any physically
(...)


title: Efficient Algebraic Effect Handlers for Prolog

abstract:
  Recent work has provided delimited control for Prolog to dynamically
manipulate the program control-flow, and to implement a wide range of
control-flow and dataflow effects on top of. Unfortunately, delimited control
is a rather primitive language feature that is not easy to use.
  As a remedy, this work introduces algebraic effect handlers for Prolog, as a
high-level and structured way of defining new side-effects in a modular
fashion. We illustrate the expressive power of the feature and provide an
implementation by means of elaboration into the delimited control primitives.
  The latter add a non-negligible performance overhead when used extensively.
To address this issue, we present an optimised compilation approach that
combines partial evaluation with dedicated rewrite rules. The rewrite rules are
driven by a lightweight effect inference that analyses what effect operations
may be called by a goal. We illustrate the effectiveness of this approach on a
range of benchmarks. This article is under consideration for acceptance in
TPLP.


title: Measurement of the Spectra of Single Bubble Sonoluminescence in water

abstract:
  A preliminary results of measurement of the spectra of Single Bubble
Sonoluminescence (SBSL) in water are presented. Analysis concentrates on
similarity and differences of spectra from black-body radiation like shape.


title:
Instrumental variables estimation of exposure effects on a time-to-event
  response using structural cumulative survival models

abstract:
  The use of instrumental variables for estimating the effect of an exposure on
an outcome is popular in econometrics, and increasingly so in epidemiology.
This increasing popularity may be attributed to the natural occurrence of
instrumental variables in observational studies that incorporate elements of
randomization, either by design or by nature (e.g., random inheritance of
genes). Instrumental variables estimation of exposure effects is well
established for continuous outcomes and to some extent for binary outcomes. It
is, however, largely lacking for time-to-event outcomes because of
complications due to censoring and survivorship bias. In this paper, we make a
novel proposal under a class of structural cumulative survival models which
parameterize time-varying effects of a point exposure directly on the scale of
the survival function; these models are essentially equivalent with a
semi-parametric variant of the instrumental variables additive hazards model.
We propose a class of recursive instrumental variable estimators for these
exposure effects, and derive their large sample properties along with
inferential tools. We examine the performance of the proposed method in
simulation studies and illustrate it in a Mendelian randomization study to
evaluate the effect of diabetes on mortality using data from the Health and
Retirement Study. We further use the proposed method to investigate potential
benefit from breast cancer screening on subsequent breast cancer mortality
based on the HIP-study.


title:
Dark-ages reionization and galaxy formation simulation--VII. The sizes
  of high-redshift galaxies

abstract:
  We investigate high-redshift galaxy sizes using a semi-analytic model
constructed for the Dark-ages Reionization And Galaxy-formation Observables
from Numerical Simulation project. Our fiducial model, including strong
feedback from supernovae and photoionization background, accurately reproduces
the evolution of the stellar mass function and UV luminosity function. Using
this model, we study the size--luminosity relation of galaxies and find that
the effective radius scales with UV luminosity as $R_\mathrm{e}\propto
L^{0.25}$ at $z{\sim}5$--$9$. We show that recently discovered very luminous
galaxies at $z{\sim}7$ (Bowler et al. 2016) and $z{\sim}11$ (Oesch et al. 2016)
lie on our predicted size--luminosity relations. We find that a significant
fraction of galaxies at $z>8$ will not be resolved by JWST, but GMT will have
the ability to resolve all galaxies in haloes above the atomic cooling limit.
We show that our fiducial model successfully reproduces the redshift evolution
of average galaxy sizes at $z>5$. We also explore galaxy sizes in models
without supernova feedback. The no-supernova feedback models produce galaxy
sizes that are smaller than observations. We therefore confirm that supernova
feedback plays an important role in determining the size--luminosity relation
of galaxies and its redshift evolution during reionization.


title:
On constacyclic codes over $\mathbb{Z}_4[u]/\langle u^2-1\rangle$ and
  their Gray images

abstract:
  We first define a new Gray map from $R=\mathbb{Z}_4+u\mathbb{Z}_4$ to
$\mathbb{Z}^{2}_{4}$, where $u^2=1$ and study $(1+2u)$-constacyclic codes over
$R$. Also of interest are some properties of $(1+2u)$-constacyclic codes over
$R$. Considering their $\mathbb{Z}_4$ images, we prove that the Gray images of
$(1+2u)$-constacyclic codes of length $n$ over $R$ are cyclic codes of length
$2n$ over $\mathbb{Z}_4$. In many cases the latter codes have better parameters
than those in the online database of Aydin and Asamov. We also give a corrected
version of a table of new cyclic $R$-codes published by \"Ozen et al. in Finite
Fields and Their Applications, {\bf 38}, (2016) 27-39.


title:
Besov Regularity for the Stationary Navier-Stokes Equation on Bounded
  Lipschitz Domains

abstract:
  We use the scale $B^s_{\tau}(L_\tau(\Omega))$, $1/\tau=s/d+1/2$, $s>0$, to
study the regularity of the stationary Stokes equation on bounded Lipschitz
domains $\Omega\subset\mathbb{R}^d$, $d\geq 3$, with connected boundary. The
regularity in these Besov spaces determines the order of convergence of
nonlinear approximation schemes. Our proofs rely on a combination of weighted
Sobolev estimates and wavelet characterizations of Besov spaces. By using
Banach's fixed point theorem, we extend this analysis to the stationary
Navier-Stokes equation with suitable Reynolds number and data, respectively.


title: From Schwinger Balls to Black Holes

abstract:
  We have shown intriguing similarities between Schwinger balls and black
holes. By considering black hole as a gravitational Schwinger ball, we have
derived the Bekenstein-Hawking entropy and the first law of black hole
thermodynamics as a direct result of the inverse area dependence of the
gravitational force. It is also shown that the Planck length is nothing but the
gravitational Schwinger length. The relation between the mass and the radius of
the black hole is derived by considering the black hole as a Schwinger ball of
gravitons. We show how the evolution of the entanglement entropy of the black
hole, as Page introduced many years ago, can be obtained by including gravitons
in the black hole's evaporation process and using a deformed EPR mechanism.
Also this deformed EPR mechanism can solve the information paradox. We show how
naive simultaneous usage of Page's argument and equivalence principle leads to
firewall problem.


title:
Stress-induced magnetic domain selection reveals a conical ground state
  for the multiferroic phase of Mn2GeO4

abstract:
  At ambient pressure (P) and below 5.5 K, olivine-type Mn2GeO4 hosts a
multiferroic (MF) phase where a multicomponent, i.e., multi-k magnetic order
generates spontaneous ferromagnetism and ferroelectricity (FE) along the c
axis. Under high P the FE disappears above 6 GPa, yet the P evolution of the
magnetic structure remained unclear based on available data. Here we report
high P single crystal neutron diffraction experiments in theMF phase at T = 4.5
K.We observe clearly that the incommensurate spiral component of the magnetic
order responsible for FE varies little with P up to 5.1 GPa. With support from
high P synchrotron x-ray diffraction measurements at room temperature (T), the
P driven suppression of FE is proposed to occur as a consequence of a crystal
structure transition away from the olivine structure. In addition, in the low T
neutron scattering experiments an emergent nonhydrostatic P component, i.e., a
uniaxial stress, leads to the selection of certain multi-k domains. We use this
observation to deduce a double-k conical magnetic structure for the ambient P
ground state, this being a key ingredient for a model description of the MF
phase.


title:
Successful Entrapment of Carbon Dots within Flexible Free-Standing
  Transparent Mesoporous Organic-Inorganic Silica Hybrid Films for Photonic
  Applications

abstract:
  The effective entrapment of Carbon dots (CDs) into a polymer-silica hybrid
matrix, formed as free standing transparent flexible films, is presented. CDs
of 3 nm mean size with strong photoluminescence are embedded into a silica
matrix during the sol-gel procedure, using tetraethylorthosilicate and F127
triblock copolymer as the structure directing agent under acidic conditions.
The final hybrid nanostructure forms free standing transparent films that show
high flexibility and long term stable CDs luminescence indicating the
protective character of the hybrid matrix. It is crucial that the
photoluminescence of the hybrid's CDs is not seriously affected after thermal
treatment at 550C for 30min. Moreover, the herein reported hybrid is
demonstrated to be suitable for the fabrication of advanced photonic structures
using soft lithography process due to its low shrinkage and distortion upon
drying.


title: Uniqueness of the Fourier transform on the Euclidean motion group

abstract:
  In this article, we prove that if the Fourier transform of a certain
integrable function on the Euclidean motion group is of finite rank, then the
function has to vanish identically. Further, we explore a new variance of the
uncertainty principle, the Heisenberg uniqueness pairs on the Euclidean motion
group as well as on the product group $\mathbb R^n\times K,$ where $K$ is a
compact group.


title: Using Dust as Probes to Determine Sheath Extent and Structure

abstract:
  Two in-situ experimental methods are presented in which dust particles are
used to determine the extent of the sheath and gain information about the
time-averaged electric force profile within a RF plasma sheath. These methods
are advantageous because they are not only simple and quick to carry out, but
they also can be performed using standard dusty plasma experimental equipment.
In the first method, dust particles are tracked as they fall through the plasma
toward the lower electrode. These trajectories are then used to determine the
electric force on the particle as a function of height as well as the extent of
the sheath. In the second method, dust particle levitation height is measured
across a wide range of RF voltages. Similarities were observed between the two
experiments, but in order to understand the underlying physics behind these
observations, the same conditions were replicated using a self-consistent fluid
model. Through comparison of the fluid model and experimental results, it is
shown that the particles exhibiting a levitation height that is independent of
RF voltage indicate the sheath edge - the boundary between the quasineutral
bulk plasma and the sheath. Therefore, both of these simple and inexpensive,
yet effective, methods can be applied across a wide range of experimental
parameters in any ground-based RF plasma chamber to gain useful information
regarding the sheath, which is needed for interpretation of dusty plasma
experiments.


title:
Spin dynamics and magnetic interactions of Mn dopants in the topological
  insulator Bi$_2$Te$_3$

abstract:
  The magnetic and electronic properties of the magnetically doped topological
insulator Bi$_{\rm 2-x}$Mn$_{\rm x}$Te$_3$ were studied using electron spin
resonance (ESR) and measurements of static magnetization and electrical
transport. The investigated high quality single crystals of Bi$_{\rm
2-x}$Mn$_{\rm x}$Te$_3$ show a ferromagnetic phase transition for $x\geq 0.04$
at $T_{C}\approx 12$ K. The Hall measurements reveal a p-type finite
charge-carrier density. Measurements of the temperature dependence of the ESR
signal of Mn dopants for different orientations of the external magnetic field
give evidence that the localized Mn moments interact with the mobile charge
carriers leading to a Ruderman-Kittel-Kasuya-Yosida-type ferromagnetic coupling
between the Mn spins of order 2-3 meV. Furthermore, ESR reveals a
low-dimensional character of magnetic correlations that persist far above the
ferromagnetic ordering temperature.


title:
The continuity and uniqueness of the value function of the hybrid
  optimal control problem with reach time to a target set

abstract:
  The hybrid optimal control problem with reach time to a target set is
addressed and the continuity and uniqueness of the associated value function is
proved. Hybrid systems involves interaction of different types of dynamics:
continuous and discrete dynamics. The state ofa continuous system is evolved by
an ordinary differential equation until the trajectory hits the predefined jump
sets: an autonomous jump set and a controlled jump set . At each jump the
trajectory is moved discontinuously to another Euclidean space by a discrete
system. We study the hybrid optimal control problem with reach time to a target
set, prove the continuity of the associated value function with respect to the
initial point under the assumption that is lower semicontinuous on the boundary
of a target set, and also characterize it as an unique solution of a
quasi-variational inequality in a viscosity sense using the dynamic programming
principle.


title: Spontaneous Breaking of Lorentz Symmetry with an antisymmetric tensor

abstract:
  Spontaneous violation of Lorentz symmetry by the vacuum condensation of an
antisymmetric $2$-tensor is considered. The coset construction for nonlinear
realization of spacetime symmetries is employed to build the most general
low-energy effective action for the Goldstone modes interacting with photons.
We analyze the model within the context of the Standard-Model Extension and
noncommutative QED. Experimental bounds for some parameters of the model are
discussed, and we readdress the subtle issues of stability and causality in
Lorentz non-invariant scenarios. Besides the two photon polarizations, just one
Goldstone mode must be dynamical to set a sensible low-energy effective model,
and the enhancement of the stability by accounting interaction terms points to
a protection against observational Lorentz violation.


title: On the geometry of random convex sets between polytopes and zonotopes

abstract:
  In this work we study a class of random convex sets that "interpolate"
between polytopes and zonotopes. These sets arise from considering a
$q^{th}$-moment ($q\geq 1$) of an average of order statistics of
$1$-dimensional marginals of a sequence of $N\geq n$ independent random vectors
in $\mathbb R^n$. We consider the random model of isotropic log-concave
distributions as well as the uniform distribution on an $\ell_p^n$-sphere
($1\leq p < \infty$) with respect to the cone probability measure, and study
the geometry of these sets in terms of the support function and mean width. We
provide asymptotic formulas for the expectation of these geometric functionals
which are sharp up to absolute constants. Our model includes and generalizes
the standard one for random polytopes.


title:
Implicit-Explicit difference schemes for nonlinear fractional
  differential equations with non-smooth solutions

abstract:
  We propose second-order implicit-explicit (IMEX) time-stepping schemes for
nonlinear fractional differential equations with fractional order $0<\beta<1$.
From the known structure of the non-smooth solution and by introducing
corresponding correction terms, we can obtain uniformly second-order accuracy
from these schemes. We prove the convergence and linear stability of the
proposed schemes. Numerical examples illustrate the flexibility and efficiency
of the IMEX schemes and show that they are effective for nonlinear and
multi-rate fractional differential systems as well as multi-term fractional
differential systems with non-smooth solutions.


title:
Particle system algorithm and chaos propagation related to
  non-conservative McKean type stochastic differential equations

abstract:
  We discuss numerical aspects related to a new class of nonlinear Stochastic
Differential Equations in the sense of McKean, which are supposed to represent
non conservative nonlinear Partial Differential equations (PDEs). We propose an
original interacting particle system for which we discuss the propagation of
chaos. We consider a time-discretized approximation of this particle system to
which we associate a random function which is proved to converge to a solution
of a regularized version of a nonlinear PDE.


title:
Periodic structures described by the perturbed Burgers-Korteweg-de Vries
  equation

abstract:
  We study the perturbed Burgers-Korteweg-de Vries equation. This equation can
be used for the description of nonlinear waves in a liquid with gas bubbles and
for the description of nonlinear waves on a fluid layer flowing down an
inclined plane. We investigate the integrability of this equation using the
Painlev\'{e} approach. We show that the perturbed Burgers-Korteweg-de Vries
equation does not belong to the class of integrable equations. Classical and
nonclassical symmetries admitted by this equation and corresponding symmetry
reductions are constructed. New types of periodic analytical structures
described by the Burgers-Korteweg-de Vries equation are found.


title:
The Brou\'e-Malle-Rouquier conjecture for the exceptional groups of rank
  2

abstract:
  Between 1994 and 1998, the work of M. Brou\'e, G. Malle, and R. Rouquier
generalized in a natural way the definition of the Hecke algebra associated to
a finite Coxeter group, for the case of an arbitrary complex reflection group.
Attempting to also generalize the properties of the Coxeter case, they stated a
number of conjectures concerning these Hecke algebras. One specific example of
importance regarding those yet unsolved conjectures is the so-called BMR
freeness conjecture. This conjecture is known to be true apart from 16 cases,
that are almost all the exceptional groups of rank 2. These exceptional groups
of rank 2 fall into three families: the tetrahedral, octahedral and icosahedral
family. We prove the validity of the BMR freeness conjecture for the
exceptional groups belonging to the first two families, using a case-by-case
analysis and we give a nice description of the basis, similar to the classical
case of the finite Coxeter groups. We also give a new consequence of this
conjecture, by obtaining the classification of irreducible representations of
the braid group on 3 strands in dimension at most 5, recovering results of Tuba
and Wenzl.


title: High Accuracy Android Malware Detection Using Ensemble Learning

abstract:
  With over 50 billion downloads and more than 1.3 million apps in the Google
official market, Android has continued to gain popularity amongst smartphone
users worldwide. At the same time there has been a rise in malware targeting
the platform, with more recent strains employing highly sophisticated detection
avoidance techniques. As traditional signature based methods become less potent
in detecting unknown malware, alternatives are needed for timely zero-day
discovery. Thus this paper proposes an approach that utilizes ensemble learning
for Android malware detection. It combines advantages of static analysis with
the efficiency and performance of ensemble machine learning to improve Android
malware detection accuracy. The machine learning models are built using a large
repository of malware samples and benign apps from a leading antivirus vendor.
Experimental results and analysis presented shows that the proposed method
which uses a large feature space to leverage the power of ensemble learning is
capable of 97.3 to 99 percent detection accuracy with very low false positive
rates.


title: RESPECT: Neutron Resonance Spin-Echo Spectrometer for Extreme Studies

abstract:
  We propose the design of a Resonance SPin-echo spECtrometer for exTreme
studies, RESPECT, that is ideally suited for the exploration of non-dispersive
processes such as diffusion, crystallization, slow dynamics, tunneling
processes, crystal electric field excitations, and spin fluctuations. It is a
variant of the conventional neutron spin-echo technique (NSE) by i) replacing
the long precession coils by pairs of longitudinal neutron spin-echo coils
combined with RF-spin flippers and ii) by stabilizing the neutron polarization
with small longitudinal guide fields that can in addition be used as field
subtraction coils thus allowing to adjust the field integrals over a range of 8
orders of magnitude. Therefore, the dynamic range of RESPECT can in principle
be varied over 8 orders of magnitude in time, if neutrons with the required
energy are made available. Similarly as for existing NSE-spectrometers, spin
echo times of up to approximately 1 microsecond can be reached if the
divergence and the correction elements are properly adjusted. Thanks to the
optional use of neutron guides and the fact that the currents for the
correction coils are much smaller than in standard NSE, intensity gains of at
least one order of magnitude are expected , making the concept of RESPECT also
competitive for operation at medium flux neutron sources. RESPECT can also be
operated in a MIEZE configuration allowing the investigation of relaxation
processes in depolarizing environments as they occur when magnetic fields are
applied at the sample position, i.e. for the investigation of the dynamics of
flux lines in superconductors, magnetic fluctuations in ferromagnetic
materials, and samples containing hydrogen.


title:
Topological Phases of Spin-1/2 Ferromagnetic--Antiferromagnetic
  Alternating Heisenberg Chains with Alternating Next-Nearest-Neighbour
  Interaction

abstract:
  A series of symmetry-protected topological(SPT) and trivial spin-gap phases
in the spin-1/2 ferromagnetic--antiferromagnetic alternating Heisenberg chain
with alternating next-nearest-neighbour interaction are investigated using two
kinds of entanglement spectra defined by different divisions of the whole
chain. In the case one of the next-nearest-neighbor interaction vanishes, the
model reduces to the $\Delta$-chain in which a series of spin-gap phases are
found in J. Phys. Soc. Jpn. 77, 044707 (2008). From the degeneracy of the
entanglement spectra, these phases are identified as the SPT and trivial
phases. It is found that the ground state phases boundaries are insensitive to
the strength of the alternation in next-nearest neighbor interaction. These
results are consistent with the analysis based on the nonlinear $\sigma$ model
and exact solution on the ferromagnetic-nonmagnetic phase boundary.


title: The cause of spatial structure in solar He I 1083 nm multiplet images

abstract:
  Context. The He i 1083 nm is a powerful diagnostic for inferring properties
of the upper solar chromosphere, in particular for the magnetic field. The
basic formation of the line in one-dimensional models is well understood, but
the influence of the complex 3D structure of the chromosphere and corona has
however never been investigated. This structure must play an essential role
because images taken in He i 1083 nm show structures with widths down to 100
km. Aims. To understand the effect of the three-dimensional temperature and
density structure in the solar atmosphere on the formation of the He i 1083 nm
line. Methods. We solve the non-LTE radiative transfer problem assuming
statistical equilibrium for a simple 9-level helium atom that nevertheless
captures all essential physics. As a model atmosphere we use a snapshot from a
3D radiation-MHD simulation computed with the Bifrost code. Ionising radiation
from the corona is self-consistently taken into account. Results. The emergent
intensity in the He i 1083 nm is set by the source function and the opacity in
the upper chromosphere. The former is dominated by scattering of photospheric
radiation and does not vary much with spatial location. The latter is
determined by the photonionisation rate in the He i ground state continuum, as
well as the electron density in the chromosphere. The spatial variation of the
flux of ionising radiation is caused by the spatially-structured emissivity of
the ionising photons from material at T = 100 kK in the transition region. The
hotter coronal material produces more ionising photons, but the resulting
radiation field is smooth and does not lead to small-scale variation of the UV
flux. The corrugation of the transition region further increases the spatial
variation of the amount of UV radiation in the chromosphere.


title:
A Framework for Context-Driven End-to-End QoS Control in Converged
  Networks

abstract:
  This paper presents a framework for context-driven policy-based QoS control
and end-to-end resource management in converged next generation networks. The
Converged Networks QoS Framework (CNQF) is being developed within the IU-ATC
project, and comprises distributed functional entities whose instances
co-ordinate the converged network infrastructure to facilitate scalable and
efficient end-to-end QoS management. The CNQF design leverages aspects of
TISPAN, IETF and 3GPP policy-based management architectures whilst also
introducing important innovative extensions to support context-aware QoS
control in converged networks. The framework architecture is presented and its
functionalities and operation in specific application scenarios are described.


title:
A Discrepancy-based Framework to Compare Robustness between
  Multi-Attribute Evaluations

abstract:
  Multi-objective evaluation is a necessary aspect when managing complex
systems, as the intrinsic complexity of a system is generally closely linked to
the potential number of optimization objectives. However, an evaluation makes
no sense without its robustness being given (in the sense of its reliability).
Statistical robustness computation methods are highly dependent of underlying
statistical models. We propose a formulation of a model-independent framework
in the case of integrated aggregated indicators (multi-attribute evaluation),
that allows to define a relative measure of robustness taking into account data
structure and indicator values. We implement and apply it to a synthetic case
of urban systems based on Paris districts geography, and to real data for
evaluation of income segregation for Greater Paris metropolitan area. First
numerical results show the potentialities of this new method. Furthermore, its
relative independence to system type and model may position it as an
alternative to classical statistical robustness methods.


title: Semantic Representations of Word Senses and Concepts

abstract:
  Representing the semantics of linguistic items in a machine-interpretable
form has been a major goal of Natural Language Processing since its earliest
days. Among the range of different linguistic items, words have attracted the
most research attention. However, word representations have an important
limitation: they conflate different meanings of a word into a single vector.
Representations of word senses have the potential to overcome this inherent
limitation. Indeed, the representation of individual word senses and concepts
has recently gained in popularity with several experimental results showing
that a considerable performance improvement can be achieved across different
NLP applications upon moving from word level to the deeper sense and concept
levels. Another interesting point regarding the representation of concepts and
word senses is that these models can be seamlessly applied to other linguistic
items, such as words, phrases and sentences.


title:
Mitochondria-based Renal Cell Carcinoma Subtyping: Learning from Deep
  vs. Flat Feature Representations

abstract:
  Accurate subtyping of renal cell carcinoma (RCC) is of crucial importance for
understanding disease progression and for making informed treatment decisions.
New discoveries of significant alterations to mitochondria between subtypes
make immunohistochemical (IHC) staining based image classification an
imperative. Until now, accurate quantification and subtyping was made
impossible by huge IHC variations, the absence of cell membrane staining for
cytoplasm segmentation as well as the complete lack of systems for robust and
reproducible image based classification. In this paper we present a
comprehensive classification framework to overcome these challenges for tissue
microarrays (TMA) of RCCs. We compare and evaluate models based on domain
specific hand-crafted "flat"-features versus "deep" feature representations
from various layers of a pre-trained convolutional neural network (CNN). The
best model reaches a cross-validation accuracy of 89%, which demonstrates for
the first time, that robust mitochondria-based subtyping of renal cancer is
feasible


title: Electric and magnetic energy at axion haloscopes

abstract:
  We review a recent letter published in Phys. Rev. Lett. $\textbf{116}$,
161804 (2016) of which the main argument is that the mode dependent magnetic
form factors at axion haloscopes depend on the position of the cavity inside
the solenoid while the corresponding electric form factors do not. We, however,
find no such dependence, which is also equivalent to the statement that the
electric and corresponding magnetic energy stored in the cavity modes are the
same regardless of the position of the cavity inside the solenoid. Furthermore,
we extend the statement to the cases satisfying $\vec{\nabla}\times\vec{B}_{\rm
external}=0$, where $\vec{B}_{\rm external}$ is a static magnetic field
provided by a magnet at an axion haloscope. Two typical magnets, solenoidal and
toroidal, satisfy $\vec{\nabla}\times\vec{B}_{\rm external}=0$, thus the
electric and corresponding magnetic energy stored in the cavity modes are
always the same in both cases. The energy, however, is independent of the
position of the cavity in axion haloscopes with a solenoid, but depends on
those with a toroidal magnet.


title:
Nonlinear Control of a DC MicroGrid for the Integration of Photovoltaic
  Panels

abstract:
  New connection constraints for the power network (Grid Codes) require more
flexible and reliable systems, with robust solutions to cope with uncertainties
and intermittence from renewable energy sources (renewables), such as
photovoltaic arrays. The interconnection of such renewables with storage
systems through a Direct Current (DC) MicroGrid can fulfill these requirements.
A "Plug and Play" approach based on the "System of Systems" philosophy using
distributed control methodologies is developed in the present work. This
approach allows to interconnect a number of elements to a DC MicroGrid as power
sources like photovoltaic arrays, storage systems in different time scales like
batteries and supercapacitors, and loads like electric vehicles and the main AC
grid. The proposed scheme can easily be scalable to a much larger number of
elements.


title: Thermodynamics of classical integrable field theories

abstract:
  We investigate the thermodynamics of integrable classical field theories
under the effect of a random initial configuration, motivated by the
nonequilibrium evolution of quantum field theories. The approach to thermal
equilibrium is analysed with numerical simulations and confronted with
analytical results. The possibility of comparing the classical results with
their quantum counterparts could be a way of inferring the behaviour of
out-of-equilibrium quantum field theories during the thermalization process.


title: Isotrivial VMRT-structures of complete intersection type

abstract:
  The family of varieties of minimal rational tangents on a quasi-homogeneous
projective manifold is isotrivial. Conversely, are projective manifolds with
isotrivial varieties of minimal rational tangents quasi-homogenous? We will
show that this is not true in general, even when the projective manifold has
Picard number 1. In fact, an isotrivial family of varieties of minimal rational
tangents needs not be locally flat in differential geometric sense. This leads
to the question for which projective variety Z, the Z-isotriviality of
varieties of minimal rational tangents implies local flatness. Our main result
verifies this for many cases of Z among complete intersections.


title: Complementarity in Quantum Information Processing Tasks

abstract:
  Complementarity have been an intriguing feature of physical systems for a
long time. In this work we establish a new kind of complimentary relations in
the frame work of quantum information processing tasks. In broadcasting of
entanglement we create many pairs of less entangled states from a given
entangled state both by local and non local cloning operations. These entangled
states can be used in various information processing tasks like teleportation
and superdense coding. Since these states are less entangled states it is quite
intuitive that these states are not going to be as powerful resource as the
initial states. In this work we study the usefulness of these states in tasks
like teleportation and super dense coding. More precisely, we found out bounds
of their capabilities in terms of several complimentary relations involving
fidelity of broadcasting. In principle we have considered general mixed as a
resource also separately providing different examples like a) Werner like
states, b) Bell diagonal states. Here we have used both local and non local
cloning operations as means of broadcasting. In the later part of our work, we
extend this result by obtaining bounds in form of complimentary relations in a
situation where we have used $1-N$ cloning transformations instead of $1-2$
cloning transformations.


title: A New Android Malware Detection Approach Using Bayesian Classification

abstract:
  Mobile malware has been growing in scale and complexity as smartphone usage
continues to rise. Android has surpassed other mobile platforms as the most
popular whilst also witnessing a dramatic increase in malware targeting the
platform. A worrying trend that is emerging is the increasing sophistication of
Android malware to evade detection by traditional signature-based scanners. As
such, Android app marketplaces remain at risk of hosting malicious apps that
could evade detection before being downloaded by unsuspecting users. Hence, in
this paper we present an effective approach to alleviate this problem based on
Bayesian classification models obtained from static code analysis. The models
are built from a collection of code and app characteristics that provide
indicators of potential malicious activities. The models are evaluated with
real malware samples in the wild and results of experiments are presented to
demonstrate the effectiveness of the proposed approach.


title:
Distributed, End-to-end Verifiable, and Privacy-Preserving Internet
  Voting Systems

abstract:
  E-voting systems are a powerful technology for improving democracy.
Unfortunately, prior voting systems have single points-of-failure, which may
compromise availability, privacy, or integrity of the election results.
  We present the design, implementation, security analysis, and evaluation of
the D-DEMOS suite of distributed, privacy-preserving, and end-to-end verifiable
e-voting systems. We present two systems: one asynchronous and one with minimal
timing assumptions but better performance. Our systems include a distributed
vote collection subsystem that does not require cryptographic operations on
behalf of the voter. We also include a distributed, replicated and
fault-tolerant Bulletin Board component, that stores all necessary
election-related information, and allows any party to read and verify the
complete election process. Finally, we incorporate trustees, who control result
production while guaranteeing privacy and end-to-end-verifiability as long as
their strong majority is honest.
  Our suite of e-voting systems are the first whose voting operation is human
verifiable, i.e., a voter can vote over the web, even when her web client stack
is potentially unsafe, without sacrificing her privacy, and still be assured
her vote was recorded as cast. Additionally, a voter can outsource election
auditing to third parties, still without sacrificing privacy.
  We provide a model and security analysis of the systems, implement complete
prototypes, measure their performance experimentally, and demonstrate their
ability to handle large-scale elections. Finally, we demonstrate the
performance trade-offs between the two versions of the system. A preliminary
version of our system was used to conduct exit-polls at three voting sites for
two national-level elections and is being adopted for use by the largest civil
union of workers in Greece, consisting of over a half million members.


title: Four-gluon scattering at three loops, infrared structure and Regge limit

abstract:
  We compute the three-loop four-gluon scattering amplitude in maximally
supersymmetric Yang-Mills theory, including its full color dependence. Our
result is the first complete computation of a non-planar four-particle
scattering amplitude to three loops in four-dimensional gauge theory and
consequently provides highly non-trivial data for the study of non-planar
scattering amplitudes. We present the amplitude as a Laurent expansion in the
dimensional regulator to finite order, with coefficients composed of harmonic
poly-logarithms of uniform transcendental weight, and simple rational
prefactors. Our computation provides an independent check of a recent result
for three-loop corrections to the soft anomalous dimension matrix that predicts
the general infrared singularity structure of massless gauge theory scattering
amplitudes. Taking the Regge limit of our result, we determine the three-loop
gluon Regge trajectory. We also find agreement with very recent predictions for
sub-leading logarithms.


title: The Brauer group of the moduli stack of elliptic curves

abstract:
  We compute the Brauer group of the moduli stack of elliptic curves over the
integers, localizations of the integers, finite fields of odd characteristic,
and algebraically closed fields of characteristic not $2$. The methods involved
include the use of the parameter space of Legendre curves and the moduli stack
of curves with full (naive) level $2$ structure, the study of the descent
spectral sequence in \'etale cohomology and the Leray spectral sequence in fppf
cohomology, the computation of the group cohomology of $S_3$ in a certain
integral representation, the classification of cubic Galois extensions of the
field of rational numbers, the computation of Hilbert symbols in the ramified
case for the primes $2$ and $3$, and finding $p$-adic elliptic curves with
specified properties.


title:
Fluctuations of the multiplicity of produced particles in onium-nucleus
  collisions

abstract:
  We address the general features of event-by-event fluctuations of the
multiplicity of gluons produced in the scattering of a dilute hadron off a
large nucleus at high energy in the fragmentation region of the dilute hadron.
We relate these fluctuations to the stochasticity of the number of quanta
contained in the hadron at the time of the interaction. For simplicity, we
address the ideal case in which the hadron is an onium, and investigate
different kinematical regimes in rapidity and onium size. We show that at large
rapidity, the multiplicity distribution exhibits an exponential tail in the
large-multiplicity region, which is qualitatively consistent with the
proton-nucleus data. But interestingly enough, the exponential shape is
determined by confinement.


title: A study of the effect of JPG compression on adversarial images

abstract:
  Neural network image classifiers are known to be vulnerable to adversarial
images, i.e., natural images which have been modified by an adversarial
perturbation specifically designed to be imperceptible to humans yet fool the
classifier. Not only can adversarial images be generated easily, but these
images will often be adversarial for networks trained on disjoint subsets of
data or with different architectures. Adversarial images represent a potential
security risk as well as a serious machine learning challenge---it is clear
that vulnerable neural networks perceive images very differently from humans.
Noting that virtually every image classification data set is composed of JPG
images, we evaluate the effect of JPG compression on the classification of
adversarial images. For Fast-Gradient-Sign perturbations of small magnitude, we
found that JPG compression often reverses the drop in classification accuracy
to a large extent, but not always. As the magnitude of the perturbations
increases, JPG recompression alone is insufficient to reverse the effect.


title:
Global existence for a nonstandard viscous Cahn-Hilliard system with
  dynamic boundary condition

abstract:
  In this paper, we study a model for phase segregation taking place in a
spatial domain that was introduced by Podio-Guidugli in Ric. Mat. 55 (2006),
pp. 105-118. The model consists of a strongly coupled system of nonlinear
parabolic differential equations, in which products between the unknown
functions and their time derivatives occur that are diffcult to handle
analytically. In contrast to the existing literature about this PDE system, we
consider here a dynamic boundary condition involving the Laplace-Beltrami
operator for the order parameter. This boundary condition models an additional
nonconserving phase transition occurring on the surface of the domain.
Different well-posedness results are shown, depending on the smoothness
properties of the involved bulk and surface free energies.


title: An Enhanced Buffer Management Scheme for Multimedia Traffic in HSDPA

abstract:
  High Speed Downlink Packet Access (HSDPA) was introduced to UMTS radio access
segment to provide higher capacity for new packet switched services. As a
result, packet switched sessions with multiple diverse traffic flows such as
concurrent voice and data, or video and data being transmitted to the same user
are a likely commonplace cellular packet data scenario. In HSDPA, Radio Access
Network (RAN) buffer management schemes are essential to support the end-to-end
QoS of such sessions. Hence in this paper we present the end-to-end performance
study of a proposed RAN buffer management scheme for multi-flow sessions via
dynamic system-level HSDPA simulations. The scheme is an enhancement of a
Time-Space Priority (TSP)queuing strategy applied to the Node B MAC-hs buffer
allocated to an end user with concurrent real-time (RT) and non-real-time (NRT)
flows during a multi-flow session. The experimental multiflow scenario is a
packet voice call with concurrent TCP-based file download to the same user.
Results show that with the proposed enhancements to the TSP-based RAN buffer
management,end-to-end QoS performance gains accrue to the NRT flow without
compromising RT flow QoS of the same end user session.


title: On the Vertex In-Degrees of Certain Jaco-Type Graphs

abstract:
  The concepts of linear Jaco graphs and Jaco-type graphs have been introduced
as certain types of directed graphs with specifically defined adjacency
conditions. The distinct difference between a pure Jaco graph and a Jaco-type
graph is that for a pure Jaco graph, the total vertex degree $d(v)$ is
well-defined, while for a Jaco-type graph the vertex out-degree $d^+(v)$ is
well-defined. Hence, in the case of pure Jaco graphs a challenge is to
determine $d^-(v)$ and $d^+(v)$ respectively and for Jaco-type graphs a
challenge is to determine $d^-(v)$. In this paper, the vertex in-degrees for
Fibonaccian and modular Jaco-type graphs are determined.


title: Sobolev extensions of Lipschitz mappings into metric spaces

abstract:
  Wenger and Young proved that the pair $(\mathbb{R}^m,\mathbb{H}^n)$ has the
Lipschitz extension property for $m \leq n$ where $\mathbb{H}^n$ is the
sub-Riemannian Heisenberg group. That is, for some $C>0$, any $L$-Lipschitz map
from a subset of $\mathbb{R}^m$ into $\mathbb{H}^n$ can be extended to a
$CL$-Lipschitz mapping on $\mathbb{R}^m$. In this paper, we construct Sobolev
extensions of such Lipschitz mappings with no restriction on the dimension $m$.
We prove that any Lipschitz mapping from a compact subset of $\mathbb{R}^m$
into $\mathbb{H}^n$ may be extended to a Sobolev mapping on any bounded domain
containing the set. More generally, we prove this result in the case of
mappings into any Lipschitz $(n-1)$-connected metric space.


title: Upper Minkowski dimension estimates for convex restrictions

abstract:
  We show that there are functions $f$ in the H\"older class $C^{ { \alpha
}}[0,1]$, $1< { \alpha }<2$ such that $f|_{A}$ is not convex, nor concave for
any $A { \subset } [0,1]$ with $ { \bar { dim }_M } A> { \alpha }-1$.
  Our earlier result shows that for the typical/generic $f\in { C_ { 1 } ^ { {
\alpha } } [0,1] }$, $0\leq { \alpha }<2$ there is always a set $A { \subset }
[0,1]$ such that $f|_A$ is convex and $ { \bar { dim }_M } A=1$.
  The analogous statement for monotone restrictions is the following: there are
functions $f$ in the H\"older class $C^{ { \alpha }}[0,1]$, $1/2 \leq { \alpha
}<1$ such that $f|_{A}$ is not monotone on $A { \subset } [0,1]$ with $ { \bar
{ dim }_M } A> { \alpha }$. This statement is not true for the range of
parameters $ { \alpha }<1/2$ and our theorem for the parameter range $1\leq {
\alpha } <3/2$ cannot be obtained by integration of the result about monotone
restrictions.


title:
Temporal Segment Networks: Towards Good Practices for Deep Action
  Recognition

abstract:
  Deep convolutional networks have achieved great success for visual
recognition in still images. However, for action recognition in videos, the
advantage over traditional methods is not so evident. This paper aims to
discover the principles to design effective ConvNet architectures for action
recognition in videos and learn these models given limited training samples.
Our first contribution is temporal segment network (TSN), a novel framework for
video-based action recognition. which is based on the idea of long-range
temporal structure modeling. It combines a sparse temporal sampling strategy
and video-level supervision to enable efficient and effective learning using
the whole action video. The other contribution is our study on a series of good
practices in learning ConvNets on video data with the help of temporal segment
network. Our approach obtains the state-the-of-art performance on the datasets
of HMDB51 ( $ 69.4\% $) and UCF101 ($ 94.2\% $). We also visualize the learned
ConvNet models, which qualitatively demonstrates the effectiveness of temporal
segment network and the proposed good practices.


title: Hierarchically Compositional Kernels for Scalable Nonparametric Learning

abstract:
  We propose a novel class of kernels to alleviate the high computational cost
of large-scale nonparametric learning with kernel methods. The proposed kernel
is defined based on a hierarchical partitioning of the underlying data domain,
where the Nystr\"om method (a globally low-rank approximation) is married with
a locally lossless approximation in a hierarchical fashion. The kernel
maintains (strict) positive-definiteness. The corresponding kernel matrix
admits a recursively off-diagonal low-rank structure, which allows for fast
linear algebra computations. Suppressing the factor of data dimension, the
memory and arithmetic complexities for training a regression or a classifier
are reduced from $O(n^2)$ and $O(n^3)$ to $O(nr)$ and $O(nr^2)$, respectively,
where $n$ is the number of training examples and $r$ is the rank on each level
of the hierarchy. Although other randomized approximate kernels entail a
similar complexity, empirical results show that the proposed kernel achieves a
matching performance with a smaller $r$. We demonstrate comprehensive
experiments to show the effective use of the proposed kernel on data sizes up
to the order of millions.


title: On the characteristic function of a collection of sets

abstract:
  The union of a collection of $n$ sets is generally expressed in terms of a
characteristic (indicator) function that contains $2^{n}-1$ terms. In this
article, a much simpler expression is found that requires the evaluation of $n$
terms only. This leads to a major simplification of any normal form involving
characteristic functions of sets. The formula can be useful in recognizing
inclusion-exclusion patterns of combinatorial problems.


title:
On the relationship between the Collatz conjecture and Mersenne prime
  numbers

abstract:
  The purpose of this study is to show how to get a necessary criterion for
prime numbers with the help of special matrices. My special interest lies in
the empirical research of these matrices and their patterns, structures and
symmetries. The matrices in turn depend on an expansion of the Collatz
algorithm 3n+1.


title:
Measurement of the direct CP violating charge asymmetry in $B^\pm
  \rightarrow \mu^\pm \nu_\mu D^{0}$ decays

abstract:
  We present the first measurement of the CP violating charge asymmetry in
$B^\pm \to \mu^\pm \nu_\mu {D}^0$ decays using the full Run II integrated
luminosity of 10.4 fb$^{-1}$ in proton-antiproton collisions collected with the
D0 detector at the Fermilab Tevatron Collider. We measure a difference in the
yield of $B^-$ and $B^+$ mesons in these decays by fitting the reconstructed
invariant mass distributions. This results in an asymmetry of $A^{\mu D^{0}}
=\left[ -0.14 \pm 0.20 \right]\%$, which is consistent with standard model
predictions.


title: Quantum dynamics of impurities coupled to a Fermi sea

abstract:
  We consider the dynamics of an impurity atom immersed in an ideal Fermi gas
at zero temperature. We focus on the coherent quantum evolution of the impurity
following a quench to strong impurity-fermion interactions, where the
interactions are assumed to be short range like in cold-atom experiments. To
approximately model the many-body time evolution, we use a truncated basis
method, where at most two particle-hole excitations of the Fermi sea are
included. When the system is initially non-interacting, we show that our method
exactly captures the short-time dynamics following the quench, and we find that
the overlap between initial and final states displays a universal non-analytic
dependence on time in this limit. We further demonstrate how our method can be
used to compute the impurity spectral function, as well as describe many-body
phenomena involving coupled impurity spin states, such as Rabi oscillations in
a medium or highly engineered quantum quenches.


title: Sparse Suffix Tree Construction in Optimal Time and Space

abstract:
  Suffix tree (and the closely related suffix array) are fundamental structures
capturing all substrings of a given text essentially by storing all its
suffixes in the lexicographical order. In some applications, we work with a
subset of $b$ interesting suffixes, which are stored in the so-called sparse
suffix tree. Because the size of this structure is $\Theta(b)$, it is natural
to seek a construction algorithm using only $O(b)$ words of space assuming
read-only random access to the text. We design a linear-time Monte Carlo
algorithm for this problem, hence resolving an open question explicitly stated
by Bille et al. [TALG 2016]. The best previously known algorithm by I et al.
[STACS 2014] works in $O(n\log b)$ time. Our solution proceeds in $n/b$ rounds;
in the $r$-th round, we consider all suffixes starting at positions congruent
to $r$ modulo $n/b$. By maintaining rolling hashes, we lexicographically sort
all interesting suffixes starting at such positions, and then we merge them
with the already considered suffixes. For efficient merging, we also need to
answer LCE queries in small space. By plugging in the structure of Bille et al.
[CPM 2015] we obtain $O(n+b\log b)$ time complexity. We improve this structure,
which implies a linear-time sparse suffix tree construction algorithm. We
complement our Monte Carlo algorithm with a deterministic verification
procedure. The verification takes $O(n\sqrt{\log b})$ time, which improves upon
the bound of $O(n\log b)$ obtained by I et al. [STACS 2014]. This is obtained
by first observing that the pruning done inside the previous solution has a
rather clean description using the notion of graph spanners with small
multiplicative stretch. Then, we are able to decrease the verification time by
applying difference covers twice. Combined with the Monte Carlo algorithm, this
gives us an $O(n\sqrt{\log b})$-time and $O(b)$-space Las Vegas algorithm.


title: PageRank in Malware Categorization

abstract:
  In this paper, we propose a malware categorization method that models malware
behavior in terms of instructions using PageRank. PageRank computes ranks of
web pages based on structural information and can also compute ranks of
instructions that represent the structural information of the instructions in
malware analysis methods. Our malware categorization method uses the computed
ranks as features in machine learning algorithms. In the evaluation, we compare
the effectiveness of different PageRank algorithms and also investigate bagging
and boosting algorithms to improve the categorization accuracy.


title: Deriving Conclusions From Non-Monotonic Cause-Effect Relations

abstract:
  We present an extension of Logic Programming (under stable models semantics)
that, not only allows concluding whether a true atom is a cause of another
atom, but also deriving new conclusions from these causal-effect relations.
This is expressive enough to capture informal rules like "if some agent's
actions $\mathcal{A}$ have been necessary to cause an event $E$ then conclude
atom $caused(\mathcal{A},E)$," something that, to the best of our knowledge,
had not been formalised in the literature. To this aim, we start from a first
attempt that proposed extending the syntax of logic programs with so-called
causal literals. These causal literals are expressions that can be used in rule
bodies and allow inspecting the derivation of some atom $A$ in the program with
respect to some query function $\phi$. Depending on how these query functions
are defined, we can model different types of causal relations such as
sufficient, necessary or contributory causes, for instance. The initial
approach was specifically focused on monotonic query functions. This was enough
to cover sufficient cause-effect relations but, unfortunately, necessary and
contributory are essentially non-monotonic. In this work, we define a semantics
for non-monotonic causal literals showing that, not only extends the stable
model semantics for normal logic programs, but also preserves many of its usual
desirable properties for the extended syntax. Using this new semantics, we
provide precise definitions of necessary and contributory causal relations and
briefly explain their behaviour on a pair of typical examples from the
Knowledge Representation literature. (Under consideration for publication in
Theory and Practice of Logic Programming)


title:
How a single particle modifies the physical reality of two distant
  others simultaneously: a quantum nonlocality and weak value study

abstract:
  The concept of wave-particle duality, which is a key element of quantum
theory, has been remarkably found to manifest itself in several experimental
realizations as in the famous double-slit experiment. In this specific case, a
single particle seems to travel through two separated slits simultaneously.
Nevertheless, it is never possible to measure it in both slits, which naturally
appears as a manifestation of the collapse postulate. In this respect, one
could as well ask if it is possible to "perceive" the presence of the particle
at the two slits simultaneously, once its collapse could be avoided. In this
article, we use the recently proposed entanglement mediation protocol to
provide a positive answer to this question. It is shown that a photon which
behaves like a wave, i.e., which seems to be present in two distant locations
at the same time, can modify two existing physical realities in these
locations. Calculations of the "weak trace" left by such photon also enforce
the validity of the present argumentation.


title: SimVerb-3500: A Large-Scale Evaluation Set of Verb Similarity

abstract:
  Verbs play a critical role in the meaning of sentences, but these ubiquitous
words have received little attention in recent distributional semantics
research. We introduce SimVerb-3500, an evaluation resource that provides human
ratings for the similarity of 3,500 verb pairs. SimVerb-3500 covers all normed
verb types from the USF free-association database, providing at least three
examples for every VerbNet class. This broad coverage facilitates detailed
analyses of how syntactic and semantic phenomena together influence human
understanding of verb meaning. Further, with significantly larger development
and test sets than existing benchmarks, SimVerb-3500 enables more robust
evaluation of representation learning architectures and promotes the
development of methods tailored to verbs. We hope that SimVerb-3500 will enable
a richer understanding of the diversity and complexity of verb semantics and
guide the development of systems that can effectively represent and interpret
this meaning.


title: Justifications for Programs with Disjunctive and Causal-choice Rules

abstract:
  In this paper, we study an extension of the stable model semantics for
disjunctive logic programs where each true atom in a model is associated with
an algebraic expression (in terms of rule labels) that represents its
justifications. As in our previous work for non-disjunctive programs, these
justifications are obtained in a purely semantic way, by algebraic operations
(product, addition and application) on a lattice of causal values. Our new
definition extends the concept of causal stable model to disjunctive logic
programs and satisfies that each (standard) stable model corresponds to a
disjoint class of causal stable models sharing the same truth assignments, but
possibly varying the obtained explanations. We provide a pair of illustrative
examples showing the behaviour of the new semantics and discuss the need of
introducing a new type of rule, which we call causal-choice. This type of rule
intuitively captures the idea of "$A$ may cause $B$" and, when causal
information is disregarded, amounts to a usual choice rule under the standard
stable model semantics. (Under consideration for publication in Theory and
Practice of Logic Programming)


title: Statistical properties of levels and lines in complex spectra

abstract:
  We review recent developments of the statistical properties of complex atomic
spectra, based on the pioneering work of Claire Bauche-Arnoult and Jacques
Bauche. We discuss several improvements of the statistical methods (UTA, SOSA)
for the modeling of the lines in a transition array: impact of high-order
moments, choice of the distribution (Generalized Gaussian, Normal Inverse
Gaussian) and corrections at low temperatures. The second part of the paper
concerns general properties of transition arrays, such as propensity rule and
generalized J-file sum rule (for E1 or E2 lines), emphasizing the particular
role of the G1 exchange Slater integral. The statistical modeling introduced by
J. Bauche and C. Bauche-Arnoult for the distribution of the M values
(projection of total angular momentum J) in an electron configuration, written
P(M), was extended in order to account for configurations with a high-l
spectator and a new analytical formula for the evaluation of the number of E1
lines with a wider range of applicability was derived.


title:
Dark matter interpretations of ATLAS searches for the electroweak
  production of supersymmetric particles in $\sqrt{s} = 8$ TeV proton-proton
  collisions

abstract:
  A selection of searches by the ATLAS experiment at the LHC for the
electroweak production of SUSY particles are used to study their impact on the
constraints on dark matter candidates. The searches use $20\,{\rm fb}^{-1}$ of
proton-proton collision data at $\sqrt{s}=8$ TeV. A likelihood-driven scan of a
five-dimensional effective model focusing on the gaugino--higgsino and Higgs
sector of the phenomenological minimal supersymmetric Standard Model is
performed. This scan uses data from direct dark matter detection experiments,
the relic dark matter density and precision flavour physics results. Further
constraints from the ATLAS Higgs mass measurement and SUSY searches at LEP are
also applied. A subset of models selected from this scan are used to assess the
impact of the selected ATLAS searches in this five-dimensional parameter space.
These ATLAS searches substantially impact those models for which the mass
$m(\tilde{\chi}^0_1)$ of the lightest neutralino is less than 65 GeV, excluding
86% of such models. The searches have limited impact on models with larger
$m(\tilde{\chi}^0_1)$ due to either heavy electroweakinos or compressed mass
spectra where the mass splittings between the produced particles and the
lightest supersymmetric particle is small.


title:
On distribution of points with algebraically conjugate coordinates in
  neighborhood of smooth curves

abstract:
  Let $\varphi:\mathbb{R}\rightarrow \mathbb{R}$ be a continuously
differentiable function on an interval $J\subset\mathbb{R}$ and let
$\boldsymbol{\alpha}=(\alpha_1,\alpha_2)$ be a point with algebraically
conjugate coordinates such that the minimal polynomial $P$ of
$\alpha_1,\alpha_2$ is of degree $\leq n$ and height $\leq Q$. Denote by
$M^n_\varphi(Q,\gamma, J)$ the set of such points $\boldsymbol{\alpha}$ such
that $|\varphi(\alpha_1)-\alpha_2|\leq c_1 Q^{-\gamma}$. We show that for a
real $0<\gamma<1$ and any sufficiently large $Q$ there exist positive values
$c_2<c_3$, where $c_i=c_i(n)$, $i=1,2$, which are independent of $Q$, such that
$c_2 Q^{n+1-\gamma}<\# M^n_{\varphi}(Q,\gamma, J)< c_3 Q^{n+1-\gamma}$.


title: Modelling and computation using NCoRM mixtures for density regression

abstract:
  Normalized compound random measures are flexible nonparametric priors for
related distributions. We consider building general nonparametric regression
models using normalized compound random measure mixture models. Posterior
inference is made using a novel pseudo-marginal Metropolis-Hastings sampler for
normalized compound random measure mixture models. The algorithm makes use of a
new general approach to the unbiased estimation of Laplace functionals of
compound random measures (which includes completely random measures as a
special case). The approach is illustrated on problems of density regression.


title:
Quantized Coulomb branches of Jordan quiver gauge theories and
  cyclotomic rational Cherednik algebras

abstract:
  We study quantized Coulomb branches of quiver gauge theories of Jordan type.
We prove that the quantized Coulomb branch is isomorphic to the spherical
graded Cherednik algebra in the unframed case, and is isomorphic to the
spherical cyclotomic rational Cherednik algebra in the framed case. We also
prove that the quantized Coulomb branch is a deformation of a subquotient of
the Yangian of the affine $\mathfrak{gl}(1)$.

categories: math.RT hep-th math-ph math.AG math.DG math.MP


title: Relational Similarity Machines

abstract:
  This paper proposes Relational Similarity Machines (RSM): a fast, accurate,
and flexible relational learning framework for supervised and semi-supervised
learning tasks. Despite the importance of relational learning, most existing
methods are hard to adapt to different settings, due to issues with efficiency,
scalability, accuracy, and flexibility for handling a wide variety of
classification problems, data, constraints, and tasks. For instance, many
existing methods perform poorly for multi-class classification problems, graphs
that are sparsely labeled or network data with low relational autocorrelation.
In contrast, the proposed relational learning framework is designed to be (i)
fast for learning and inference at real-time interactive rates, and (ii)
flexible for a variety of learning settings (multi-class problems), constraints
(few labeled instances), and application domains. The experiments demonstrate
the effectiveness of RSM for a variety of tasks and data.


title:
Nonperturbative quasi-classical theory of the nonlinear electrodynamic
  response of graphene

abstract:
  An electromagnetic response of a single graphene layer to a uniform,
arbitrarily strong electric field $E(t)$ is calculated by solving the kinetic
Boltzmann equation within the relaxation-time approximation. The theory is
valid at low (microwave, terahertz, infrared) frequencies satisfying the
condition $\hbar\omega\lesssim 2E_F$, where $E_F$ is the Fermi energy. We
investigate the saturable absorption and higher harmonics generation effects,
as well as the transmission, reflection and absorption of radiation incident on
the graphene layer, as a function of the frequency and power of the incident
radiation and of the ratio of the radiative to scattering damping rates. We
show that the optical bistability effect, predicted in Phys. Rev. B 90, 125425
(2014) on the basis of a perturbative approach, disappears when the problem is
solved exactly. We show that, under the action of a high-power radiation
($\gtrsim 100$ kW/cm$^2$) both the reflection and absorption coefficients
strongly decrease and the layer becomes transparent.


title: On the Use of Computer Programs as Money

abstract:
  Money is a technology for promoting economic prosperity. Over history money
has become increasingly abstract, it used to be hardware, gold coins and the
like, now it is mostly software, data structures located in banks. Here I
propose the logical conclusion of the abstraction of money: to use as money the
most general form of information - computer programs. The key advantage that
using programs for money (program-money) adds to the technology of money is
agency. Program-money is active and thereby can fully participate in economics
as economic agents. I describe the three basic technologies required to
implement program-money: computational languages/logics to unambiguously
describe the actions and interactions of program-money; computational
cryptography to ensure that only the correct actions and interactions are
performed; and a distributed computational environment in which the money can
execute. I demonstrate that most of the technology for program-money has
already been developed. The adoption of program-money transfers responsibility
from human economic agents to money itself and has great potential economic
advantages over the current passive form of money. For example in
microeconomics, adding agency to money will simplify the exchange of ownership,
ensure money is only used legally, automate the negotiation and forming of
contracts, etc. Similar advantages occur in macroeconomics, where for example
the control of the money supply could be transferred from central banks to
money. It is also possible to envisage money that is not owned by any external
human agent or corporation. One motivation for this is to force economic
systems to behave more rationally and/or more like a specific economic theory,
thereby increasing the success of economic forecasting.


title:
Prospects of In-Flight Hyperfine Spectroscopy of (Anti)Hydrogen for
  Tests of CPT Symmetry

abstract:
  The ground-state hyperfine splitting of antihydrogen promises one of the most
sensitive tests of CPT symmetry. The ASACUSA collaboration is pursuing a
measurement of this splitting in a Rabi-type experiment using a polarized beam
from a CUSP magnet at the Antiproton Decelerator of CERN. With the initial
intention of characterizing the Rabi apparatus, a polarized source of cold
hydrogen was built and the $\sigma_1$ transition of hydrogen was measured to a
few ppb precision. A measurement of the $\pi_1$ transition is being prepared.
The availability of this beam opens the possibility to perform first
measurements of some coefficients within the nonminimal Standard-Model
Extension.


title:
A Spectroscopic Survey of Electronic Transitions of C$_6$H,
  $^{13}$C$_6$H, and C$_6$D

abstract:
  Electronic spectra of C$_6$H are measured in the $18\,950-21\,100$ cm$^{-1}$
domain using cavity ring-down spectroscopy of a supersonically expanding
hydrocarbon plasma. In total, 19 (sub)bands of C$_6$H are presented, all
probing the vibrational manifold of the B$^2\Pi$ electronically excited state.
The assignments are guided by electronic spectra available from matrix
isolation work, isotopic substitution experiments (yielding also spectra for
$^{13}$C$_6$H and C$_6$D), predictions from ab initio calculations as well as
rotational fitting and vibrational contour simulations using the available
ground state parameters as obtained from microwave experiments. Besides the
$0_0^0$ origin band, three non-degenerate stretching vibrations along the
linear backbone of the C$_6$H molecule are assigned: the $\nu_6$ mode
associated with the C-C bond vibration and the $\nu_4$ and $\nu_3$ modes
associated with C$\equiv$C triple bonds. For the two lowest $\nu_{11}$ and
$\nu_{10}$ bending modes, a Renner-Teller analysis is performed identifying the
$\mu^2\Sigma$($\nu_{11}$) and both $\mu^2\Sigma$($\nu_{10}$) and
$\kappa^2\Sigma$($\nu_{10}$) components. In addition, two higher lying bending
modes are observed, which are tentatively assigned as $\mu^2\Sigma$($\nu_9$)
and $\mu^2\Sigma$($\nu_8$) levels. In the excitation region below the first
non-degenerate vibration ($\nu_6$), some $^2\Pi-^{2}\Pi$ transitions are
observed that are assigned as even combination modes of low-lying bending
vibrations. The same holds for a $^2\Pi-^{2}\Pi$ transition found above the
$\nu_6$ level. From these spectroscopic data and the vibronic analysis a
comprehensive energy level diagram for the B$^2\Pi$ state of C$_6$H is derived
and presented.


title:
Enumerative and bijective aspects of combinatorial maps: generalization,
  unification and application (PhD thesis)

abstract:
  This thesis deals with the enumerative study of combinatorial maps, and its
application to the enumeration of other combinatorial objects.
  Combinatorial maps, or simply maps, form a rich combinatorial model. They
have an intuitive and geometric definition, but are also related to some deep
algebraic structures. For instance, a special type of maps called
constellations provides a unifying framework for some enumeration problems
concerning factorizations in the symmetric group. Standing on a position where
many domains meet, maps can be studied using a large variety of methods, and
their enumeration can also help us count other combinatorial objects. This
thesis is a sampling from the rich results and connections in the enumeration
of maps.
  This thesis is structured into four major parts. The first part, including
Chapter 1 and 2, consist of an introduction to the enumerative study of maps.
The second part, Chapter 3 and 4, contains my work in the enumeration of
constellations, which are a special type of maps that can serve as a unifying
model of some factorizations of the identity in the symmetric group. The third
part, composed by Chapter 5 and 6, shows my research on the enumerative link
from maps to other combinatorial objects, such as generalizations of the Tamari
lattice and random graphs embeddable onto surfaces. The last part is the
closing chapter, in which the thesis concludes with some perspectives and
future directions in the enumerative study of maps.


title:
Effect of temperature and magnetic field on two-flavor superconducting
  quark matter

abstract:
  We investigate the effect of turning on temperature for the charge neutral
phase of two-flavor color superconducting (2SC) dense quark matter in presence
of constant external magnetic field. Within the Nambu-Jona-Lasinio model, by
tuning the diquark coupling strength, we study the interdependent evolution of
the quark Bardeen-Cooper-Schrieffer gap and dynamical mass as functions of
temperature and magnetic field. We find that magnetic field $B \gtrsim 0.02$
GeV$^2$ ($10^{18}$ G) leads to anomalous temperature behavior of the gap in the
gapless 2SC phase (moderately strong coupling), reminiscent of previous results
in the literature found in the limit of weak coupling without magnetic field.
The 2SC gap in the strong coupling regime is abruptly quenched at ultrahigh
magnetic field due to the mismatched Fermi surfaces of up and down quarks
imposed by charge neutrality and oscillation of the gap due to Landau level
quantization. The dynamical quark mass also displays strong oscillation and
magnetic catalysis at high magnetic field, although the latter effect is
tempered by nonzero temperature. We discuss the implications for newly born
compact stars with superconducting quark cores.


title:
Direct Evaluation of $n$-point single-trace MHV amplitudes in 4d
  Einstein-Yang-Mills theory using the CHY Formalism

abstract:
  In this paper we extend our techniques, developed in a previous paper (Du,
etc, JHEP 05(2016)086) for direct evaluation of arbitrary $n$-point tree-level
MHV amplitudes in 4d Yang-Mills and gravity theory using the Cachazo-He-Yuan
(CHY) formalism, to the 4d Einstein-Yang-Mills (EYM) theory. Any single-trace
color-ordered $n$-point tree-level MHV amplitude in EYM theory, obtained by a
direct evaluation of the CHY formula, is of an elegant factorized form of a
Parke-Taylor factor and a Hodges determinant, much simpler and more compact
than the existing formulas in the literature. We prove that our new expression
is equivalent to the conjectured Selivanov-Bern-De Freitas-Wong (SBDW) formula,
with the help of a new theorem showing that the SBDW generating function has a
graph theory interpretation. Together with Ref. (Du, etc, JHEP 05(2016)086), we
provide strong analytic evidence for hidden simplicity in quantum field theory.


title:
Atomic-scale observation and manipulation of plaquette antiferromagnetic
  order in iron-based superconductor

abstract:
  The symmetry requirement and the origin of magnetic orders coexisting with
superconductivity have been strongly debated issues of iron-based
superconductors (FeSCs). Observation of C$_4$-symmetric antiferromagnetism in
violation of the inter-band nesting condition of spin-density waves in
superconducting ground state will require significant change in our
understanding of the mechanism of FeSC. The superconducting material
Sr$_2$VO$_3$FeAs, a bulk version of monolayer FeSC in contact with a perovskite
layer with its magnetism (T$_N$ ~ 50 K) and superconductivity (T$_c$ ~ 37 K)
coexisting at parent state, has no reported structural orthorhombic distortion
and thus makes a perfect system to look for theoretically expected C$_4$
magnetisms. Based on variable temperature spin-polarized scanning tunneling
microscopy (SPSTM) with newly discovered imaging mechanism that removes the
static surface reconstruction (SR) pattern by fluctuating it rapidly with
spin-polarized tunneling current, we could visualize underlying C$_4$ symmetric
(2$\times$2) magnetic domains and its phase domain walls. We find that this
magnetic order is perfectly consistent with the plaquette antiferromagnetic
order in tetragonal Fe spin lattice expected from theories based on the
Heisenberg exchange interaction of local Fe moments and the quantum order by
disorder. The inconsistency of its modulation Q vectors from the nesting
condition also implies that the nesting-based C$_2$ symmetric magnetism is not
a unique prerequisite of high-T$_c$ FeSC. Furthermore, the plaquette
antiferromagnetic domain wall dynamics under the influence of small spin torque
effect of spin-polarized tunneling current are shown to be consistent with
theoretical simulation based on the extended Landau-Lifshitz-Gilbert equation.


title:
SPECTRWM: Spectral Random Walk Method for the Numerical Solution of
  Stochastic Partial Differential Equations

abstract:
  The numerical solution of stochastic partial differential equations (SPDE)
presents challenges not encountered in the simulation of PDEs or SDEs. Indeed,
the roughness of the noise in conjunction with nonlinearities in the drift
typically make these equations particularly stiff. In practice, this means that
it is tricky to construct, operate, and validate numerical methods for SPDEs.
This is especially true if one is interested in path-dependent expected values,
long-time simulations, or in the simulation of SPDEs whose solutions have
constraints on their domains. To address these numerical issues, this paper
introduces a Markov jump process approximation for SPDEs, which we refer to as
the spectral random walk method (SPECTRWM). The accuracy and ergodicity of
SPECTRWM are verified in the context of a heat and overdamped Langevin SPDE,
respectively. We also apply the method to Burgers and KPZ SPDEs.

categories: math.PR cond-mat.stat-mech math-ph math.MP


title:
Correlation of Fe-based Superconductivity and Electron-Phonon Coupling
  in an FeAs/Oxide Heterostructure

abstract:
  Interfacial phonons between iron-based superconductors (FeSCs) and perovskite
substrates have received considerable attention due to the possibility of
enhancing preexisting superconductivity. Using scanning tunneling spectroscopy,
we studied the correlation between superconductivity and e-ph interaction with
interfacial-phonons in an iron-based superconductor Sr$_2$VO$_3$FeAs ($T_c
\approx$ 33 K) made of alternating FeSC and oxide layers. The quasiparticle
interference measurement over regions with systematically different average
superconducting gaps due to the e-ph coupling locally modulated by O vacancies
in VO$_2$ layer, and supporting self-consistent momentum-dependent Eliashberg
calculations provide a unique real-space evidence of the forward-scattering
interfacial phonon contribution to the total superconducting pairing.


title: Towards Learning to Perceive and Reason About Liquids

abstract:
  Recent advances in AI and robotics have claimed many incredible results with
deep learning, yet no work to date has applied deep learning to the problem of
liquid perception and reasoning. In this paper, we apply fully-convolutional
deep neural networks to the tasks of detecting and tracking liquids. We
evaluate three models: a single-frame network, multi-frame network, and a LSTM
recurrent network. Our results show that the best liquid detection results are
achieved when aggregating data over multiple frames and that the LSTM network
outperforms the other two in both tasks. This suggests that LSTM-based neural
networks have the potential to be a key component for enabling robots to handle
liquids using robust, closed-loop controllers.


title: Identifying the ejected population from disintegrating multiple systems

abstract:
  Kinematic studies of the Hipparcos catalogue have revealed associations that
are best explained as disintegrating multiple systems, presumably resulting
from a dynamical encounter between single/multiple systems in the field (Li et
al. 2009). In this work we explore the possibility that known ultra-cool dwarfs
may be components of disintegrating multiple systems, and consider the
implications for the properties of these objects. We will present here the
methods/techniques that can be used to search for and identify disintegrating
benchmark systems in three database/catalogues: Dwarf Archive, the Hipparcos
Main Catalogue, and the Gliese-Jahrei{\ss} Catalogue. Placing distance
constraints on objects with parallax or colour-magnitude information from
spectrophotometry allowed us to identify common distance associations. Proper
motion measurements allowed us to separate common proper motion multiples from
our sample of disintegrating candidates. Moreover, proper motion and positional
information allowed us to select candidate systems based on relative component
positions that were tracked back and projected forward through time. Using this
method we identified one candidate disintegrating quadruple association, and
two candidate disintegrating binaries, all of them containing one ultra-cool
dwarf.


title: Approximating the Maximum Number of Synchronizing States in Automata

abstract:
  We consider the problem {\sc Max Sync Set} of finding a maximum synchronizing
set of states in a given automaton. We show that the decision version of this
problem is PSPACE-complete and investigate the approximability of {\sc Max Sync
Set} for binary and weakly acyclic automata (an automaton is called weakly
acyclic if it contains no cycles other than self-loops). We prove that,
assuming $P \ne NP$, for any $\varepsilon > 0$, the {\sc Max Sync Set} problem
cannot be approximated in polynomial time within a factor of $O(n^{1 -
\varepsilon})$ for weakly acyclic $n$-state automata with alphabet of linear
size, within a factor of $O(n^{\frac{1}{2} - \varepsilon})$ for binary
$n$-state automata, and within a factor of $O(n^{\frac{1}{3} - \varepsilon})$
for binary weakly acyclic $n$-state automata. Finally, we prove that for unary
automata the problem becomes solvable in polynomial time.


title:
Search for Minimal Supersymmetric Standard Model Higgs bosons $H/A$ and
  for a $Z^{\prime}$ boson in the $\tau \tau$ final state produced in $pp$
  collisions at $\sqrt{s}=13$ TeV with the ATLAS Detector

abstract:
  A search for neutral Higgs bosons of the Minimal Supersymmetric Standard
Model (MSSM) and for a heavy neutral $Z^{\prime}$ boson is performed using a
data sample corresponding to an integrated luminosity of 3.2 fb$^{-1}$ from
proton--proton collisions at $\sqrt{s} = 13$ TeV recorded by the ATLAS detector
at the LHC. The heavy resonance is assumed to decay to a $\tau^+ \tau^-$ pair
with at least one $\tau$ lepton decaying to final states with hadrons and a
neutrino. The search is performed in the mass range of 0.2--1.2 TeV for the
MSSM neutral Higgs bosons and 0.5--2.5 TeV for the heavy neutral $Z^{\prime}$
boson. The data are in good agreement with the background predicted by the
Standard Model and hence results are given as upper limits on the production
cross section times branching fraction of the boson decay to $\tau^+\tau^-$ as
a function of the boson mass. The results are interpreted in MSSM and
$Z^{\prime}$ benchmark scenarios. The most stringent MSSM parameter space
constraints for the Higgs boson search exclude at 95\% confidence level (CL)
$\tan\beta > 7.6$ for $m_A = 200$ GeV in the $m_{h}^{\textrm{mod+}}$ MSSM
scenario. This analysis extends the MSSM limits from previous searches for the
mass range $m_A > 500$ GeV. For the Sequential Standard Model, a
$Z^{\prime}_\mathrm{SSM}$ mass up to 1.90 TeV is excluded at 95% CL and masses
up to 1.82--2.17 TeV are excluded for a $Z^{\prime}_{\mathrm{SFM}}$ of the
Strong Flavour Model.