title: Thingi10K: A Dataset of 10,000 3D-Printing Models

abstract:
  Empirically validating new 3D-printing related algorithms and implementations
requires testing data representative of inputs encountered \emph{in the wild}.
An ideal benchmarking dataset should not only draw from the same distribution
of shapes people print in terms of class (e.g., toys, mechanisms, jewelry),
representation type (e.g., triangle soup meshes) and complexity (e.g., number
of facets), but should also capture problems and artifacts endemic to 3D
printing models (e.g., self-intersections, non-manifoldness). We observe that
the contextual and geometric characteristics of 3D printing models differ
significantly from those used for computer graphics applications, not to
mention standard models (e.g., Stanford bunny, Armadillo, Fertility). We
present a new dataset of 10,000 models collected from an online 3D printing
model-sharing database. Via analysis of both geometric (e.g., triangle aspect
ratios, manifoldness) and contextual (e.g., licenses, tags, classes)
characteristics, we demonstrate that this dataset represents a more concise
summary of real-world models used for 3D printing compared to existing
datasets. To facilitate future research endeavors, we also present an online
query interface to select subsets of the dataset according to project-specific
characteristics. The complete dataset and per-model statistical data are freely
available to the public.


title: Dissipative two-level systems under ultrastrong off-resonant driving

abstract:
  We study the dissipative dynamics of a two-level system under ultrastrong
driving when the frequency and strength of the exciting field exceed
significantly the transition frequency. We find three qualitatively different
regimes of such dynamics: 1) the collapse and revival of oscillations in the
population difference, 2) the simple exponential decay of the oscillations
resulting in their steady state with the finite amplitude, and 3) the
steady-state stabilization of the equally populated levels. The nonmonotonic
Bessel-function-like dependence on the driving strength is also predicted for
the decay rate of these oscillations. The features of this dependence are
determined by the relative rates of energetic relaxation and pure dephasing.


title:
Orion's Veil: Magnetic field strengths and other properties of a PDR in
  front of the Trapezium Cluster

abstract:
  We present an analysis of physical conditions in the Orion Veil, a largely
atomic PDR that lies just in front (about 2 pc) of the Trapezium stars. We have
obtained 21 cm HI and 18 cm OH VLA Zeeman effect data. These data yield images
of the line-of-sight magnetic field strength Blos in atomic and molecular
regions of the Veil. We find Blos is typically -50 to -75 microgauss in the
atomic gas across much of the Veil (25" resolution); Blos is -350 microgauss at
one position in the molecular gas (40" resolution). The Veil has two principal
HI velocity components. Magnetic and kinematical data suggest a close
connection between these components. They may represent gas on either side of a
shock wave preceding a weak-D ionization front. Magnetic fields in the Veil HI
components are 3-5 times stronger than they are elsewhere in the ISM where N(H)
and n(H) are comparable. The HI components are magnetically subcritical
(magnetically dominated), like the CNM, although they are about 1 dex denser.
Strong fields in the Veil HI components may have resulted from low turbulence
conditions in the diffuse gas that gave rise to OMC-1. Strong fields may also
be related to magnetostatic equilibrium that has developed in the Veil since
star formation. We consider the location of the Orion-S molecular core,
proposing a location behind the main Orion H+ region.


title:
Log-linear Combinations of Monolingual and Bilingual Neural Machine
  Translation Models for Automatic Post-Editing

abstract:
  This paper describes the submission of the AMU (Adam Mickiewicz University)
team to the Automatic Post-Editing (APE) task of WMT 2016. We explore the
application of neural translation models to the APE problem and achieve good
results by treating different models as components in a log-linear model,
allowing for multiple inputs (the MT-output and the source) that are decoded to
the same target language (post-edited translations). A simple string-matching
penalty integrated within the log-linear model is used to control for higher
faithfulness with regard to the raw machine translation output. To overcome the
problem of too little training data, we generate large amounts of artificial
data. Our submission improves over the uncorrected baseline on the unseen test
set by -3.2\% TER and +5.5\% BLEU and outperforms any other system submitted to
the shared-task by a large margin.


title: On the Explicit Torsion Anomalous Conjecture

abstract:
  The Torsion Anomalous Conjecture states that an irreducible variety $V$
embedded in a semi-abelian variety contains only finitely many maximal
$V$-torsion anomalous varieties. In this paper we consider an irreducible
variety embedded in a product of elliptic curves. Our main result provides a
totally explicit bound for the N\'eron-Tate height of all maximal $V$-torsion
anomalous points of relative codimension one, in the non CM case, and an
analogous effective result in the CM case. As an application, we obtain the
finiteness of such points. In addition, we deduce some new explicit results in
the context of the effective Mordell-Lang Conjecture; in particular we bound
the N\'eron-Tate height of the rational points of an explicit family of curves
of increasing genus.


title: Dust loss from activated asteroid P/2015 X6

abstract:
  We present observations and dust tail models of activated asteroid P/2015 X6
from deep imaging data acquired at the 10.4m Gran Telescopio Canarias (GTC)
from mid-December 2015 to late January 2016. The results of the modeling
indicate that the asteroid has undergone a sustained dust loss over a two-month
or longer period. The dust parameters, derived from multidimensional fits of
the available images, are compatible with either ice sublimation or rotational
instability processes. An impulsive event, as it could be associated to an
impact with another body, is less likely. A power-law distribution of
particles, with minimum and maximum radius of 1 $\mu$m and 1 cm, and power
index of --3.3 is found to be consistent with the observations. Depending on
the ejection velocity model adopted, the particle velocities are found in the
0.3 to 10 m s$^{-1}$ range. The activation time was between 18-26 days before
discovery. The total ejected mass from that time to the most recent observation
is in the range 5-9$\times$10$^6$ kg. No dust features giving indication of
past activity earlier than the activation time have been observed.


title:
Why should a birational geometer care about Bridgeland stability
  conditions?

abstract:
  In this survey we borrow from Coskun and Huizenga an example of application
of Bridgeland stability conditions to birational geometry and we rephrase it
without assuming any previous knowledge about derived categories.


title: Diphoton resonance confronts dark matter

abstract:
  As an interpretation of the 750 GeV diphoton excesses recently reported by
both ATLAS and CMS collaborations, we consider a simple extension of the
Standard Model with a Dirac fermion dark matter where a singlet complex scalar
field mediates between dark matter and SM particles via effective couplings to
SM gauge bosons and/or Higgs-portal. In this model, we can accommodate the
diphoton events through the direct and/or cascade decays of pseudo-scalar and
real scalar partners of the complex scalar field. We show that mono-jet
searches and gamma-ray observations are complementary in constraining the
region where the width of the diphoton resonance can be enhanced due to the
couplings of the resonance to dark matter and the correct relic density is
obtained. In the case of cascade decay of the resonance, the effective
couplings of singlet scalars can be smaller, but the model is still testable by
the future discrimination between single photon and photon-jet at the LHC as
well as the gamma-ray searches for the cascade annihilation of dark matter.


title: Achievable information rates of ambient backscatter communications

abstract:
  Ambient backscatter is an intriguing wireless communication paradigm that
allows small devices to compute and communicate by using only the power they
harvest from radio-frequency (RF) signals in the air. Ambient backscattering
devices reflect existing RF signals emitted by legacy communications systems,
such as digital TV broadcasting, cellular or Wi-Fi ones, which would be
otherwise treated as harmful sources of interference. This paper deals with the
ultimate performance limits of ambient backscatter systems in broadband fading
environments, by considering different amounts of network state information at
the receivers. After introducing a detailed signal model of the relevant
communication links, we study the influence of physical parameters on the
capacity of both legacy and backscatter systems. We find that, under reasonable
operative conditions, a legacy system employing multicarrier modulation can
turn the RF interference arising from the backscatter process into a form of
multipath diversity that can be suitably exploited to noticeably increase its
performance. Moreover, we show that, even when employing simple single-carrier
modulation techniques, the backscatter system can achieve significant data
rates over relatively short distances, especially when the intended recipient
of the backscatter signal is co-located with the legacy transmitter, i.e., they
are on the same machine.


title:
Multilevel Thresholding Segmentation of T2 weighted Brain MRI images
  using Convergent Heterogeneous Particle Swarm Optimization

abstract:
  This paper proposes a new image thresholding segmentation approach using the
heuristic method, Convergent Heterogeneous Particle Swarm Optimization
algorithm. The proposed algorithm incorporates a new strategy of searching the
problem space by dividing the swarm into subswarms. Each subswarm particles
search for better solution separately lead to better exploitation while they
cooperate with each other to find the best global position. The consequence of
the aforementioned cooperation is better exploration, convergence and it able
the algorithm to jump from local optimal solution to the better spots. A
practical application of this method is demonstrated for the problem of medical
image thresholding segmentation. We considered two classical thresholding
techniques of Otsu and Kapur separately as the objective function for the
optimization method and applied on a set of brain MR images. Comparative
experimental results reveal that the proposed method outperforms another state
of the art method from the literature in terms of accuracy, computation time
and stable results.


title: Restricted growth function patterns and statistics

abstract:
  A restricted growth function (RGF) of length n is a sequence w = w_1 w_2 ...
w_n of positive integers such that w_1 = 1 and w_i is at most 1 + max{w_1,...,
w_{i-1}} for i at least 2. RGFs are of interest because they are in natural
bijection with set partitions of {1, 2, ..., n}. RGF w avoids RGF v if there is
no subword of w which standardizes to v. We study the generating functions
sum_{w in R_n(v)} q^{st(w)} where R_n(v) is the set of RGFs of length n which
avoid v and st(w) is any of the four fundamental statistics on RGFs defined by
Wachs and White. These generating functions exhibit interesting connections
with integer partitions and two-colored Motzkin paths, as well as noncrossing
and nonnesting set partitions.


title: Enhanced security for multi-detector Quantum Random Number Generators

abstract:
  Quantum random number generators (QRNG) represent an advanced solution for
randomness generation, essential in every cryptographic applications. In this
context, integrated arrays of single photon detectors have promising
applications as QRNGs based on the spatial detection of photons. For the
employment of QRNGs in Cryptography, it is necessary to have efficient methods
to evaluate the so called quantum min-entropy that corresponds to the amount of
the true extractable quantum randomness from the QRNG. Here we present an
efficient method that allow to estimate the quantum min-entropy for a
multi-detector QRNG. In particular, we will consider a scenario in which an
attacker can control the efficiency of the detectors and knows the emitted
number of photons. Eventually, we apply the method to a QRNG with $10^3$
detectors.


title:
The AMU-UEDIN Submission to the WMT16 News Translation Task:
  Attention-based NMT Models as Feature Functions in Phrase-based SMT

abstract:
  This paper describes the AMU-UEDIN submissions to the WMT 2016 shared task on
news translation. We explore methods of decode-time integration of
attention-based neural translation models with phrase-based statistical machine
translation. Efficient batch-algorithms for GPU-querying are proposed and
implemented. For English-Russian, our system stays behind the state-of-the-art
pure neural models in terms of BLEU. Among restricted systems, manual
evaluation places it in the first cluster tied with the pure neural model. For
the Russian-English task, our submission achieves the top BLEU result,
outperforming the best pure neural system by 1.1 BLEU points and our own
phrase-based baseline by 1.6 BLEU. After manual evaluation, this system is the
best restricted system in its own cluster. In follow-up experiments we improve
results by additional 0.8 BLEU.


title:
On scaling limits of multitype Galton-Watson trees with possibly
  infinite variance

abstract:
  In this work, we study asymptotics of multitype Galton-Watson trees with
finitely many types. We consider critical and irreducible offspring
distributions such that they belong to the domain of attraction of a stable
law, where the stability indices may differ. We show that after a proper
rescaling, their corresponding height process converges to the continuous-time
height process associated with a strictly stable spectrally positive L\'evy
process. This gives an analogue of a result obtained by Miermont in the case of
multitype Galton-Watson trees with finite covariance matrices of the offspring
distribution. Our approach relies on a remarkable decomposition for multitype
trees into monotype trees introduced by Miermont.


title: The evanescence of rest masses and electric charge in black holes

abstract:
  The classical Einstein-Standard Model system with conformally invariant
coupling of the Higgs field to gravity is investigated in nearly Schwarzschild
black holes. We show that, in the presence of Kantowski-Sachs symmetries, there
is a finite critical value of the mean curvature such that on spacelike
hypersurfaces with greater mean curvature the Higgs sector does not have any
symmetry breaking vacuum state. Hence, according to the Standard Model of
particle physics, the gauge and spinor fields do not have rest mass and
electric charge. Therefore, particles falling into a nearly Schwarzschild black
hole lose their mass and charge in the "reverse" Brout-Englert-Higgs mechanism.


title: Off-policy evaluation for slate recommendation

abstract:
  This paper studies the evaluation of policies that recommend an ordered set
of items (e.g., a ranking) based on some context---a common scenario in web
search, ads, and recommendation. We build on techniques from combinatorial
bandits to introduce a new practical estimator that uses logged data to
estimate a policy's performance. A thorough empirical evaluation on real-world
data reveals that our estimator is accurate in a variety of settings, including
as a subroutine in a learning-to-rank task, where it achieves competitive
performance. We derive conditions under which our estimator is unbiased---these
conditions are weaker than prior heuristics for slate evaluation---and
experimentally demonstrate a smaller bias than parametric approaches, even when
these conditions are violated. Finally, our theory and experiments also show
exponential savings in the amount of required data compared with general
unbiased estimators.


title:
Photonic light trapping in silicon nanowire arrays: deriving and
  overcoming the physical limitations

abstract:
  Hexagonally aligned, free-standing silicon nanowire (SiNW) arrays serve as
photonic resonators which, as compared to a silicon (Si) thin film, do not only
absorb more visible (VIS) and near-infrared (NIR) light, but also show an
inherent photonic light concentration that enhances their performance as solar
absorbers. Using numerical simulations we show, how light concentration is
induced by high optical cross sections of the individual SiNWs but cannot be
optimized independently of the SiNW array absorption. While an ideal spatial
density exists, for which the SiNW array absorption for VIS and NIR wavelengths
reaches a maximum, the spatial correlation of SiNWs in an array suppresses the
formation of optical Mie modes responsible for light concentration. We show
that different from SiNWs with straight sidewalls, arrays of inverted silicon
nanocones (SiNCs) permit to avoid the mode suppression. In fact they give rise
to an altered set of photonic modes which is induced by the spatial correlation
of SiNCs in the array, and therefore show a higher degree of freedom to
independently optimize light absorption and light concentration. Apart from
explaining the good light absorbing and concentrating properties of SiNC
arrays, the work justifies a revaluation of SiNW arrays as optical absorbers.


title: Smart Meter Privacy with Renewable Energy and a Finite Capacity Battery

abstract:
  We address the smart meter (SM) privacy problem by considering the
availability of a renewable energy source (RES) and a battery which can be
exploited by a consumer to partially hide the consumption pattern from the
utility provider (UP). Privacy is measured by the mutual information rate
between the consumer's energy consumption and the renewable energy generation
process, and the energy received from the grid, where the latter is known by
the UP through the SM readings, and the former two are to be kept private. By
expressing the information leakage as an additive quantity, we cast the problem
as a stochastic control problem, and formulate the corresponding Bellman
equations.


title:
Fluids with competing interactions: II. Validating a free energy model
  for equilibrium cluster size

abstract:
  Using computer simulations, we validate a simple free energy model that can
be analytically solved to predict the equilibrium size of self-limiting
clusters of particles in the fluid state governed by a combination of
short-range attractive and long-range repulsive pair potentials. The model is a
semi-empirical adaptation and extension of the canonical free energy-based
result due to Groenewold and Kegel [J. Phys. Chem. B, 105 (2001)], where we use
new computer simulation data to systematically improve the cluster-size
scalings with respect to the strengths of the competing interactions driving
aggregation. We find that one can adapt a classical nucleation like theory for
small energetically-frustrated aggregates provided one appropriately accounts
for a size-dependent, microscopic energy penalty of interface formation, which
requires new scaling arguments. This framework is verified in part by
considering the extensive scaling of intracluster bonding, where we uncover a
superlinear scaling regime distinct from (and located between) the known
regimes for small and large aggregates. We validate our model based on
comparisons against approximately 100 different simulated systems comprising
compact spherical aggregates with characteristic (terminal) sizes between six
and sixty monomers, which correspond to wide ranges in
experimentally-controllable parameters.


title:
A class of random walks in reversible dynamic environment: antisymmetry
  and applications to the East model

abstract:
  We introduce via perturbation a class of random walks in reversible dynamic
environments having a spectral gap. In this setting one can apply the
mathematical results derived in http://arxiv.org/abs/1602.06322. As first
results, we show that the asymptotic velocity is antisymmetric in the
perturbative parameter and, for a subclass of random walks, we characterize the
velocity and a stationary distribution of the environment seen from the walker
as suitable series in the perturbative parameter. We then consider as a special
case a random walk on the East model that tends to follow dynamical interfaces
between empty and occupied regions. We study the asymptotic velocity and
density profile for the environment seen from the walker. In particular, we
determine the sign of the velocity when the density of the underlying East
process is not 1/2, and we discuss the appearance of a drift in the balanced
setting given by density 1/2.


title:
A t-generalization for Schubert Representatives of the Affine
  Grassmannian

abstract:
  We introduce two families of symmetric functions with an extra parameter t
that specialize to Schubert representatives for cohomology and homology of the
affine Grassmannian when t = 1. The families are defined by a statistic on
combinatorial objects associated to the type-A affine Weyl group and their
transition matrix with Hall-Littlewood polynomials is t-positive. We conjecture
that one family is the set of k-atoms.


title:
Decoupling edge versus bulk conductance in the trivial regime of an
  InAs/GaSb double quantum well using Corbino ring geometry

abstract:
  A Corbino ring geometry is utilized to analyze edge and bulk conductance of
InAs/GaSb quantum well structures. We show that edge conductance exists in the
trivial regime of this theoretically-predicted topological system with a
temperature insensitive linear resistivity per unit length in the range of 2
kOhm/um. A resistor network model of the device is developed to decouple the
edge conductance from the bulk conductance, providing a quantitative technique
to further investigate the nature of this trivial edge conductance,
conclusively identified here as being of n-type.


title: Gaussian systems for quantum enhanced multiple phase estimation

abstract:
  For a fixed average energy, the simultaneous estimation of multiple phases
can provide a better total precision than estimating them individually. We show
this for a multimode interferometer with a phase in each mode, using Gaussian
inputs and passive elements, by calculating the covariance matrix. The quantum
Cram\'{e}r-Rao bound provides a lower bound to the covariance matrix via the
quantum Fisher information matrix, whose elements we derive to be the
covariances of the photon numbers across the modes. We prove that this bound
can be saturated. In spite of the Gaussian nature of the problem, the
calculation of non-Gaussian integrals is required, which we accomplish
analytically. We find our simultaneous strategy to yield no more than a
factor-of-2 improvement in total precision, possibly because of a fundamental
performance limitation of Gaussian states. Our work shows that no modal
entanglement is necessary for simultaneous quantum-enhanced estimation of
multiple phases.


title:
Theoretical lower limits on sizes of ultra faint dwarf galaxies from
  dynamical friction

abstract:
  Dwarf spheroidal galaxies are the smallest known stellar systems where under
Newtonian interpretations, a significant amount of dark matter is required to
explain observed kinematics. In fact, they are in this sense the most heavily
dark matter dominated objects known. That, plus the increasingly small sizes of
the newly discovered ultra faint dwarfs, puts these systems in the regime where
dynamical friction on individual stars starts to become relevant. We calculate
the dynamical friction timescales for pressure supported isotropic spherical
dark matter dominated stellar systems, yielding $\tau_{DF} =0.93 (r_{h}/10
pc)^{2} (\sigma/ kms^{-1}) Gyr$, { where $r_{h}$ is the half-light radius}. For
a stellar velocity dispersion value of $3 km/s$, as typical for the smallest of
the recently detected ultra faint dwarf spheroidals, dynamical friction
timescales becomes smaller than the $10 Gyr$ typical of the stellar ages for
these systems, for $r_{h}<19 pc$. Thus, this becomes a theoretical lower limit
below which dark matter dominated stellar systems become unstable to dynamical
friction. We present a comparison with structural parameters of the smallest
ultra faint dwarf spheroidals known, showing that these are already close to
the stability limit derived, any future detection of yet smaller such systems
would be inconsistent with a particle dark matter hypothesis.


title:
Boundary Treatment and Multigrid Preconditioning for Semi-Lagrangian
  Schemes Applied to Hamilton-Jacobi-Bellman Equations

abstract:
  We analyse two practical aspects that arise in the numerical solution of
Hamilton-Jacobi-Bellman (HJB) equations by a particular class of monotone
approximation schemes known as semi-Lagrangian schemes. These schemes make use
of a wide stencil to achieve convergence and result in discretization matrices
that are less sparse and less local than those coming from standard finite
difference schemes. This leads to computational difficulties not encountered
there. In particular, we consider the overstepping of the domain boundary and
analyse the accuracy and stability of stencil truncation. This truncation
imposes a stricter CFL condition for explicit schemes in the vicinity of
boundaries than in the interior, such that implicit schemes become attractive.
We then study the use of geometric, algebraic and aggregation-based multigrid
preconditioners to solve the resulting discretised systems from implicit time
stepping schemes efficiently. Finally, we illustrate the performance of these
techniques numerically for benchmark test cases from the literature.


title: Mixing solutions for the Muskat problem

abstract:
  We prove the existence of mixing solutions of the incompressible porous media
equation for all Muskat type $H^5$ initial data in the fully unstable regime.
The proof combines convex integration, contour dynamics and a basic calculus
for non smooth semiclassical type pseudodifferential operators which is
developed.


title:
Two-flavor Simulations of the $\rho(770)$ and the Role of the $K\bar K$
  Channel

abstract:
  The $\rho (770)$ meson is the most extensively studied resonance in lattice
QCD simulations in two ($N_f=2$) and three ($N_f=2+1$) flavor formulations. We
analyze $N_f=2$ lattice scattering data using unitarized Chiral Perturbation
Theory, allowing not only for the extrapolation in mass but also in flavor,
$N_f=2\to N_f=2+1$. The flavor extrapolation requires information from a global
fit to $\pi\pi$ and $\pi K$ phase shifts from experiment. While the chiral
extrapolation of $N_f=2$ lattice data leads to masses of the $\rho(770)$ meson
far below the experimental one, we find that the missing $K\bar{K}$ channel is
able to explain this discrepancy.


title: The maximum size of a partial spread in a finite projective space

abstract:
  Let $n$ and $t$ be positive integers with $t<n$, and let $q$ be a prime
power. A $\textit{partial $(t-1)$-spread}$ of ${\rm PG}(n-1,q)$ is a set of
$(t-1)$-dimensional subspaces of ${\rm PG}(n-1,q)$ that are pairwise disjoint.
Let $r=n\mbox{ mod } t$ and $0\leq r<t$. We prove that if $t>(q^r-1)/(q-1)$,
then the maximum size, i.e., cardinality, of a partial $(t-1)$-spread of ${\rm
PG}(n-1,q)$ is $(q^n-q^{t+r})/(q^t-1)+1$. This essentially settles a main open
problem in this area. Prior to this result, this maximum size was only known
for $r\in\{0,1\}$ and for $r=q=2$.


title:
Improved RNA pseudoknots prediction and classification using a new
  topological invariant

abstract:
  We propose a new topological characterization of RNA secondary structures
with pseudoknots based on two topological invariants. Starting from the classic
arc-representation of RNA secondary structures, we consider a model that
couples both I) the topological genus of the graph and II) the number of
crossing arcs of the corresponding primitive graph. We add a term proportional
to these topological invariants to the standard free energy of the RNA
molecule, thus obtaining a novel free energy parametrization which takes into
account the abundance of topologies of RNA pseudoknots observed in RNA
databases.


title:
Exact canonic eigenstates of the truncated Bogoliubov Hamiltonian in an
  interacting bosons gas

abstract:
  In a gas of $N$ weakly interacting bosons \cite{Bogo1, Bogo2}, a truncated
canonic Hamiltonian $\widetilde{h}_c$ follows from dropping all the interaction
terms between free bosons with momentum $\hbar\mathbf{k}\ne\mathbf{0}$.
Bogoliubov Canonic Approximation (BCA) is a further manipulation, replacing the
number \emph{operator} $\widetilde{N}_{in}$ of free particles in
$\mathbf{k}=\mathbf{0}$, with the total number $N$ of bosons. BCA transforms
$\widetilde{h}_c$ into a different Hamiltonian
$H_{BCA}=\sum_{\mathbf{k}\ne\mathbf{0}}\epsilon(k)B^\dagger_\mathbf{k}B_\mathbf{k}+const$,
where $B^\dagger_\mathbf{k}$ and $B_\mathbf{k}$ create/annihilate non
interacting pseudoparticles. The problem of the \emph{exact} eigenstates of the
truncated Hamiltonian is completely solved in the thermodynamic limit (TL) for
a special class of eigensolutions $|\:S,\:\mathbf{k}\:\rangle_{c}$, denoted as
\textquoteleft s-pseudobosons\textquoteright, with energies
$\mathcal{E}_{S}(k)$ and \emph{zero} total momentum. Some preliminary results
are given for the exact eigenstates (denoted as \textquoteleft
$\eta$-pseudobosons\textquoteright), carrying a total momentum
$\eta\hbar\mathbf{k}$ ($\eta=\:1,\:2,\: \dots$). A comparison is done with
$H_{BCA}$ and with the Gross-Pitaevskii theory (GPT), showing that some
differences between exact and BCA/GPT results persist even in the TL. Finally,
it is argued that the emission of $\eta$-pseudobosons, which is responsible for
the dissipation $\acute{a}$ \emph{la} Landau \cite{L}, could be significantly
different from the usual picture, based on BCA pseudobosons.


title:
A far-ultraviolet variable with an 18-minute period in the globular
  cluster NGC 1851

abstract:
  We present the detection of a variable star with an $18.05$ minute period in
far-ultraviolet (FUV) images of the globular cluster NGC 1851 taken with the
Hubble Space Telescope (HST). A candidate optical counterpart lies on the red
horizontal branch or the asymptotic giant branch star of the cluster, but it is
statistically possible that this is a chance superposition. This interpretation
is supported by optical spectroscopt obtained with HST/STIS: the spectrum
contains none of the strong emission lines that would be expected if the object
was a symbiotic star (i.e. a compact accretor fed by a giant donor). We
therefore consider two other possibilities for the nature of FUV variable: (i)
an intermediate polar (i.e. a compact binary containing an accreting magnetic
white dwarf), or (ii) an AM CVn star (i.e. an interacting double-degenerate
system). In the intermediate polar scenario, the object is expected to be an
X-ray source. However, no X-rays are detected at its location in $\simeq
65$~ksec of {\em Chandra} imaging, which limits the X-ray luminosity to $L_X
\leqslant 10^{32}$~erg~s$^{-1}$. We therefore favour the AM CVn interpretation,
but a FUV spectrum is needed to distinguish conclusively between the two
possibilities. If the object is an AM CVn binary, it would be the first such
system known in any globular cluster.


title: Geometrical splitting and reduction of Feynman diagrams

abstract:
  A geometrical approach to the calculation of N-point Feynman diagrams is
reviewed. It is shown that the geometrical splitting yields useful connections
between Feynman integrals with different momenta and masses. It is demonstrated
how these results can be used to reduce the number of variables in the
occurring functions.


title: The degree of commutativity and lamplighter groups

abstract:
  The degree of commutativity of a group $G$ measures the probability of
choosing two elements in $G$ which commute. There are many results studying
this for finite groups. In [AMV17], this was generalised to infinite groups. In
this note, we compute the degree of commutativity for wreath products of the
form $\mathbb{Z}\wr \mathbb{Z}$ and $F\wr \mathbb{Z}$ where $F$ is any finite
group.


title: Characterization of the Haagerup property for residually amenable groups

abstract:
  The notions of a box family and fibred cofinitely-coarse embedding are
introduced. The countable, residually amenable groups satisfying the Haagerup
property are then characterized as those possessing a box family that admits a
fibred cofinitely-coarse embedding into a Hilbert space. This is a
generalization of a result of X. Chen, Q. Wang and X. Wang on residually finite
groups.


title: Distributed chaos tuned to large scale coherent motions in turbulence

abstract:
  It is shown, using direct numerical simulations and laboratory experiments
data, that distributed chaos is often tuned to large scale coherent motions in
anisotropic inhomogeneous turbulence. The examples considered are: fully
developed turbulent boundary layer (range of coherence: $14 < y^{+} < 80$),
turbulent thermal convection (in a horizontal cylinder), and Cuette-Taylor
flow. Two ways of the tuning have been described: one via fundamental frequency
(wavenumber) and another via subharmonic (period doubling). For the second way
the large scale coherent motions are a natural component of distributed chaos.
In all considered cases spontaneous breaking of space translational symmetry is
accompanied by reflexional symmetry breaking.


title: Commutative algebra: Constructive methods. Finite projective modules

abstract:
  This book is an introductory course to basic commutative algebra with a
particular emphasis on finitely generated projective modules. We adopt the
constructive point of view, with which all existence theorems have an explicit
algorithmic content content.
  In particular, when a theorem affirms the existence of an object -- the
solution of a problem -- a construction algorithm of the object can always be
extracted from the given proof. We revisit with a new and often simplifying eye
several abstract classical theories. In particular, we review theories which
did not have any algorithmic content in their general natural framework, such
as Galois theory, the Dedekind domains, the finitely generated projective
modules or the Krull dimension.


title:
Alignment Solution for CT Image Reconstruction by Fixed Point and
  Virtual Rotation Axis

abstract:
  Since X-ray tomography is now widely adopted in many different areas, it
becomes more crucial to find a robust routine of handling tomographic data to
get quality reconstructed images. Though there are several existing techniques,
it seems helpful to have a more automated method to remove the possible errors
that hinder clearer image reconstruction. Here, we proposed an alternative
method and new algorithm using the sinogram and the fixed point. A new physical
concept of Center of Attenuation (CA) was also introduced to figure out how
this fixed point is applied to the image reconstruction with errors we further
categorized. Our technique showed a promising performance in restoring images
with translation and vertical tilt errors.


title:
Holographic imaging through a scattering medium by diffuser-aided
  statistical averaging

abstract:
  We introduce a practical digital holographic method capable of imaging
through a diffusive or scattering medium. The method relies on statistical
averaging from a rotating ground glass diffuser to negate the adverse effects
caused by speckle introduced by a first, static diffuser or scattering medium.
In particular, a setup based on Fourier transform holography is used to show
that an image can be recovered after scattering by introducing an additional
diffuser in the optical setup. This method is capable of recovering object
information from behind a scattering layer in biomedical or military imaging
applications.


title: On the Gap Between Separating Words and Separating Their Reversals

abstract:
  A deterministic finite automaton (DFA) separates two strings $w$ and $x$ if
it accepts $w$ and rejects $x$. The minimum number of states required for a DFA
to separate $w$ and $x$ is denoted by $sep(w,x)$. The present paper shows that
the difference $|sep(w,x)-sep(w^R,x^R)|$ is unbounded for a binary alphabet;
here $w^R$ stands for the mirror image of $w$. This solves an open problem
stated in [Demaine, Eisenstat, Shallit, Wilson: Remarks on separating words.
DCFS 2011. LNCS vol. 6808, pp. 147-157.]


title:
The Effect of Electrical Boundary Conditions on the Thermal Properties
  of Ferroelectric Piezoelectric Ceramics

abstract:
  The thermal conductivity of polycrystalline bulk PZT
(lead-zirconate-titanate) has been investigated according to electrical
boundary conditions and poling. The thermal conductivity of poled PZT was
measured in the poling direction for open circuit and short circuit conditions.
The short circuit thermal conductivity had the largest thermal conductivity.
The relationship between these two thermal properties, the electrothermal
coupling factor $k_{33}^{\kappa}$, was found to be similar to the
electromechanical coupling factor $k_{33}$ relating elastic compliance under
short circuit and open circuit conditions. The thermal conductivity of the
unpoled sample was found to have the lowest thermal conductivity. The
significance of the thermal conductivity with regards to phonon mode scattering
and elastic compliance was discussed.


title: Si K Edge Structure and Variability in Galactic X-Ray Binaries

abstract:
  We survey the Si K edge structure in various absorbed Galactic low-mass X-ray
binaries (LMXBs) to study states of silicon in the inter- and circum-stellar
medium. The bulk of these LMXBs lie toward the Galactic bulge region and all
have column densities above $10^{22}$ cm$^{-2}$. The observations were
performed with the \emph{Chandra} High Energy Transmission Grating
Spectrometer. The Si K edge in all sources appears at an energy value of
1844$\pm$0.001 eV. The edge exhibits significant substructure which can be
described by a near edge absorption feature at 1849$\pm$0.002 eV and a far edge
absorption feature at 1865$\pm$0.002 eV. Both of these absorption features
appear variable with equivalent widths up to several m\AA. We can describe the
edge structure with several components: multiple edge functions, near edge
absorption excesses from silicates in dust form, signatures from X-ray
scattering optical depths, and a variable warm absorber from ionized atomic
silicon. The measured optical depths of the edges indicate much higher values
than expected from atomic silicon cross sections and ISM abundances, and appear
consistent with predictions from silicate X-ray absorption and scattering. A
comparison with models also indicates a preference for larger dust grain sizes.
In many cases we identify \sixiii\ resonance absorption and determine
ionization parameters between log $\xi$ = 1.8 and 2.8 and turbulent velocities
between 300 and 1000 \kms. This places the warm absorber in close vicinity of
the X-ray binaries. In some data we observe a weak edge at 1.840 keV,
potentially from a lesser contribution of neutral atomic silicon.


title:
Estimation of a Multiplicative Correlation Structure in the Large
  Dimensional Case

abstract:
  We propose a Kronecker product model for correlation or covariance matrices
in the large dimensional case. The number of parameters of the model increases
logarithmically with the dimension of the matrix. We propose a minimum distance
(MD) estimator based on a log-linear property of the model, as well as a
one-step estimator, which is a one-step approximation to the quasi-maximum
likelihood estimator (QMLE). We establish rates of convergence and central
limit theorems (CLT) for our estimators in the large dimensional case. A
specification test and tools for Kronecker product model selection and
inference are provided. In a Monte Carlo study where a Kronecker product model
is correctly specified, our estimators exhibit superior performance. In an
empirical application to portfolio choice for SP500 daily returns, we
demonstrate that certain Kronecker product models are good approximations to
the general covariance matrix.


title: Tetraquarks in the 1/N expansion and meson-meson resonances

abstract:
  Diquarks are found to have the right degrees of freedom to describe the
tetraquark poles in hidden-charm to open-charm meson-meson amplitudes. Compact
tetraquarks result as intermediate states in non-planar diagrams of the 1/N
expansion and the corresponding resonances are narrower than what estimated
before. The proximity of tetraquarks to meson-thresholds has an apparent role
in this analysis and, in the language of meson molecules, an halving rule in
the counting of states is obtained.


title: Boundary value problem and the Ehrhard inequality

abstract:
  Let $I, J\subset \mathbb{R}$ be closed intervals, and let $H$ be $C^{3}$
smooth real valued function on $I\times J$ with nonvanishing $H_{x}$ and
$H_{y}$. Take any fixed positive numbers $a,b$, and let $d\mu$ be a probability
measure with finite moments and absolutely continuous with respect to Lebesgue
measure. We show that for the inequality $$ \int_{\mathbb{R}^{n}}
\mathrm{ess\,sup}_{y \in \mathbb{R}^{n}}\; H\left(
f\left(\frac{x-y}{a}\right),g\left(\frac{y}{b}\right)\right)d\mu (x) \geq
H\left(\int_{\mathbb{R}^{n}}fd\mu, \int_{\mathbb{R}^{n}}gd\mu \right) $$ to
hold for all Borel functions $f,g$ with values in $I$ and $J$ correspondingly
it is necessary that $$
a^{2}\frac{H_{xx}}{H_{x}^{2}}+(1-a^{2}-b^{2})\frac{H_{xy}}{H_{x}H_{y}}+b^{2}\frac{H_{yy}}{H_{y}^{2}}\geq
0, $$ $|a-b|\leq 1$, $a+b\geq 1$ and $\int_{\mathbb{R}^{n}}xd\mu=0$ if $a+b>1$.
Moreover, if $d\mu$ is a Gaussian measure then the necessary condition becomes
sufficient. This extends Pr\'ekopa--Leindler and Ehrhard inequalities to an
arbitrary function $H(x,y)$. As an immediate application we obtain the new
proof of the Ehrhard inequality. In particular, we show that in the class of
even probability measures with smooth positive density and finite moments the
Gaussian measure is the only one which satisfies the functional form of the
Ehrhard inequality on the real line with their own distribution functions.


title:
Superconductivity at ~ 0.049 K in Laves phase HfZn2 predicted by first
  principles

abstract:
  We report the superconductivity at Tc ~ 0.049 K in Laves phase HfZn2. Based
on the first principles method we have studied the details structural and
electronic properties of HfZn2 according to which there are 4.67 states eV-1
fu-1 at Fermi level. Using this value we calculate the specific heat
coefficient {\gamma} theoretically as 10.97 mJ/ K2 mol and then systematically
calculate the electron-phonon coupling constant {\lambda} as 0.45. Finally
applying these values in McMillan formula we get the superconducting critical
temperature of HfZn2 as approximately 0.049 K.


title:
The JCMT Gould Belt Survey: Evidence for radiative heating and
  contamination in the W40 complex

abstract:
  We present SCUBA-2 450{\mu}m and 850{\mu}m observations of the W40 complex in
the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT)
Gould Belt Survey (GBS) of nearby star-forming regions. We investigate
radiative heating by constructing temperature maps from the ratio of SCUBA-2
fluxes using a fixed dust opacity spectral index, {\beta} = 1.8, and a beam
convolution kernel to achieve a common 14.8" resolution. We identify 82 clumps
ranging between 10 and 36K with a mean temperature of 20{\pm}3K. Clump
temperature is strongly correlated with proximity to the external OB
association and there is no evidence that the embedded protostars significantly
heat the dust. We identify 31 clumps that have cores with densities greater
than 105cm{^{-3}}. Thirteen of these cores contain embedded Class 0/I
protostars. Many cores are associated with bright-rimmed clouds seen in
Herschel 70 {\mu}m images. From JCMT HARP observations of the 12CO 3-2 line, we
find contamination of the 850{\mu}m band of up to 20 per cent. We investigate
the free-free contribution to SCUBA-2 bands from large-scale and ultracompact H
ii regions using archival VLA data and find the contribution is limited to
individual stars, accounting for 9 per cent of flux per beam at 450 {\mu}m or
12 per cent at 850 {\mu}m in these cases. We conclude that radiative heating
has potentially influenced the formation of stars in the Dust Arc sub-region,
favouring Jeans stable clouds in the warm east and fragmentation in the cool
west.


title: The Variation of Photon Speed with Photon Frequency in Quantum Gravity

abstract:
  In the present work, an expression for Planck Mass or Planck Energy is
derived by equating the Compton wavelength with the gravitational radius of the
Kerr rotating body. Using the modified photon energy-momentum dispersion
relation, the variation of the photon propagation speed with photon frequency
is derived. It is found that, the photon propagation speed, depends on the
frequency of the photon, the rotation parameter of the Kerr rotating body and
also on the polarization state of the photon. Quantum gravity effect could be
seen from the derived results for the photon propagation speed.


title:
Characterization of Saturn's bow shock: Magnetic field observations of
  quasi-perpendicular shocks

abstract:
  Collisionless shocks vary drastically from terrestrial to astrophysical
regimes resulting in radically different characteristics. This poses two
complexities. Firstly, separating the influences of these parameters on
physical mechanisms such as energy dissipation. Secondly, correlating
observations of shock waves over a wide range of each parameter, enough to span
across different regimes. Investigating the latter has been restricted since
the majority of studies on shocks at exotic regimes (such as supernova
remnants) have been achieved either remotely or via simulations, but rarely by
means of in-situ observations. Here we present the parameter space of MA bow
shock crossings from 2004-2014 as observed by the Cassini spacecraft. We find
that Saturn's bow shock exhibits characteristics akin to both terrestrial and
astrophysical regimes (MA of order 100), which is principally controlled by the
upstream magnetic field strength. Moreover, we determined the {\theta}Bn of
each crossing to show that Saturn's (dayside) bow shock is predominantly
quasi-perpendicular by virtue of the Parker spiral at 10 AU. Our results
suggest a strong dependence on MA in controlling the onset of physical
mechanisms in collisionless shocks, particularly non-time stationarity and
variability. We anticipate our comprehensive assessment will yield deeper
insight into high MA collisionless shocks and provide a broader scope for
understanding the structures and mechanisms of collisionless shocks.


title:
Stellar kinematics using a third integral of motion: method and
  application on the Andromeda galaxy

abstract:
  We probe the feasibility of describing the structure of a multi-component
axisymmetric galaxy with a dynamical model based on the Jeans equations while
taking into account a third integral of motion. We demonstrate that using the
third integral in the form derived by G. Kuzmin, it is possible to calculate
the stellar kinematics of a galaxy from the Jeans equations by integrating the
equations along certain characteristic curves. In cases where the third
integral of motion does not describe the system exactly, the derived kinematics
would describe the galaxy only approximately. We apply our method to the
Andromeda galaxy, for which the mass distribution is relatively firmly known.
We are able to reproduce the observed stellar kinematics of the galaxy rather
well. The calculated model suggests that the velocity dispersion ratios
${\sigma}_z^2/{\sigma}_R^2$ of M31 decrease with increasing R. Moving away from
the galactic plane, ${\sigma}_z^2/{\sigma}_R^2$ remains the same. The velocity
dispersions ${\sigma}_{\theta}^2$ and ${\sigma}_R^2$ are roughly equal in the
galactic plane.


title: Conservativeness criteria for generalized Dirichlet forms

abstract:
  We develop sufficient analytic conditions for conservativeness of
non-sectorial perturbations of symmetric Dirichlet forms which can be
represented through a carr\'e du champ on a locally compact separable metric
space. These form an important subclass of generalized Dirichlet forms which
were introduced in \cite{St1}. In case there exists an associated strong Feller
process, the analytic conditions imply conservativeness, i.e. non-explosion of
the associated process in the classical probabilistic sense. As an application
of our general results on locally compact separable metric state spaces, we
consider a generalized Dirichlet form given on a closed or open subset of
$\mathbb{R}^d$ which is given as a divergence free first order perturbation of
a symmetric energy form. Then using volume growth conditions of the carr\'e du
champ and the non-sectorial first order part, we derive an explicit criterion
for conservativeness. We present several concrete examples which relate our
results to previous ones obtained by different authors. In particular, we show
that conservativeness can hold for a cubic variance if the drift is strong
enough to compensate it. This work continues our previous work on transience
and recurrence of generalized Dirichlet forms.


title:
A new and simple model for magneto-optics uncovers an unexpected spin
  switching

abstract:
  In magneto-optics the spin angular momentum $S_z$ of a sample is indirectly
probed by the rotation angle and ellipticity, which are mainly determined by
the off-diagonal susceptibility $\chi^{(1)}_{xy}$. A direct and analytic
relation between $S_z$ and $\chi^{(1)}_{xy}$ is necessary and of paramount
importance to the success of magneto-optics, but is often difficult to acquire
since quantum mechanically the relation is hidden in the sum-over-states. Here
we propose a new and simple model to establish such a much needed relation. Our
model is based on the Hookean model, but includes spin-orbit coupling. Under cw
excitation, we show that $\chi^{(1)}_{xy}(\omega)$ is indeed directly
proportional to $S_z$ for a fixed photon frequency $\omega$. Such an elegant
relation is encouraging, and we wonder whether our model can describe spin
dynamics as well. By allowing the spin to change dynamically, to our surprise,
our model predicts that an ultrafast laser pulse can induce a spin precession;
with appropriate parameters, the laser can even reverse spin from one direction
to another. This works for both the circularly and linearly polarized light.
The spin reversal window is narrow. These unexpected results closely resemble
all-optical helicity-dependent magnetic switching found in much more
complicated ferrimagnetic rare earth compounds. Therefore, we believe that our
spin-orbit coupled model may find some important applications in spin switching
processes, a hot topic in femtomagnetism.


title:
Test of scintillating bars coupled to Silicon Photomultipliers for a
  charged particle tracking device

abstract:
  The results obtained in laboratory tests, using scintillator bars read by
silicon photomultipliers are reported. The present approach is the first step
for designing a precision tracking system to be placed inside a free magnetized
volume for the charge identification of low energy crossing particles. The
devised system is demonstrated able to provide a spatial resolution better than
2 mm.


title:
Study of the Low-Energy Characteristics of Neutron-Neutron Scattering in
  the Effective-Range Approximation

abstract:
  The influence of the mass difference between the charged and neutral pions on
the low-energy characteristics of nucleon-nucleon interaction in the
$^{1}S_{0}$ spin-singlet state is studied within the framework of the
effective-range approximation. By making use of the experimental singlet
neutron-proton scattering parameters and the experimental value of
neutron-neutron virtual-state energy, the following values were obtained for
the neutron-neutron scattering length and effective range:
$a_{nn}=-16.59(117)$fm, $r_{nn}=2.83(11)$fm. The calculated neutron-neutron
scattering length $a_{nn}$ is in good agreement with one of the two well known
and differing experimental values of this quantity, and the calculated
effective range $r_{nn}$ is also in good agreement with present-day
experimental results.


title: Video2GIF: Automatic Generation of Animated GIFs from Video

abstract:
  We introduce the novel problem of automatically generating animated GIFs from
video. GIFs are short looping video with no sound, and a perfect combination
between image and video that really capture our attention. GIFs tell a story,
express emotion, turn events into humorous moments, and are the new wave of
photojournalism. We pose the question: Can we automate the entirely manual and
elaborate process of GIF creation by leveraging the plethora of user generated
GIF content? We propose a Robust Deep RankNet that, given a video, generates a
ranked list of its segments according to their suitability as GIF. We train our
model to learn what visual content is often selected for GIFs by using over
100K user generated GIFs and their corresponding video sources. We effectively
deal with the noisy web data by proposing a novel adaptive Huber loss in the
ranking formulation. We show that our approach is robust to outliers and picks
up several patterns that are frequently present in popular animated GIFs. On
our new large-scale benchmark dataset, we show the advantage of our approach
over several state-of-the-art methods.


title:
Reliability of Sequential Hypothesis Testing Can Be Achieved by an
  Almost-Fixed-Length Test

abstract:
  The maximum type-I and type-II error exponents associated with the newly
introduced almost-fixed-length hypothesis testing is characterized. In this
class of tests, the decision-maker declares the true hypothesis almost always
after collecting a fixed number of samples $n$; however in very rare cases with
exponentially small probability the decision maker is allowed to collect
another set of samples (no more than polynomial in $n$). This class of
hypothesis tests are shown to bridge the gap between the classical hypothesis
testing with a fixed sample size and the sequential hypothesis testing, and
improve the trade-off between type-I and type-II error exponents.


title: Vector cylindrical harmonics for low-dimensional convection models

abstract:
  Approximate empirical models of thermal convection can allow us to identify
the essential properties of the flow in simplified form, and to produce
empirical estimates using only a few parameters. Such "low-dimensional"
empirical models can be constructed systematically by writing numerical or
experimental measurements as superpositions of a set of appropriate basis
modes, a process known as Galerkin projection. For three-dimensional convection
in a cylinder, those basis modes should be vector-valued, mutually orthogonal,
and defined in cylindrical coordinates. Here we construct such a basis set and
demonstrate that it has these desired properties and boundary conditions when
the exact constraint of incompressibility is relaxed. We show its use for
representing sample simulation data and point out its potential for
low-dimensional convection models.


title: Gauge-independent Renormalization of the 2-Higgs-Doublet Model

abstract:
  The 2-Higgs-Doublet Model (2HDM) belongs to the simplest extensions of the
Standard Model (SM) Higgs sector that are in accordance with theoretical and
experimental constraints. In order to be able to properly investigate the
experimental Higgs data and, in the long term to distinguish between possible
models beyond the SM, precise predictions for the Higgs boson observables have
to be made available on the theory side. This requires the inclusion of the
higher order corrections. In this work, we investigate in detail the
renormalization of the 2HDM, a pre-requisite for the computation of higher
order corrections. We pay particular attention to the renormalization of the
mixing angles $\alpha$ and $\beta$, which diagonalize the Higgs mass matrices
and which enter all Higgs observables. The implications of various
renormalization schemes in next-to-leading order corrections to the sample
processes $H^\pm \to W^\pm h/H$ and $H \to ZZ$ are investigated. Based on our
findings, we will present a renormalization scheme that is at the same time
process independent, gauge independent and numerically stable.


title:
Tailoring Exchange Couplings in Magnetic Topological
  Insulator/Antiferromagnet Heterostructures

abstract:
  Magnetic topological insulators such as Cr-doped (Bi,Sb)2Te3 provide a
platform for the realization of versatile time-reversal symmetry-breaking
physics. By constructing heterostructures with N\'eel order in an
antiferromagnetic CrSb and magnetic topological order in Cr-doped (Bi,Sb)2Te3,
we realize emergent interfacial magnetic phenomena which can be tailored
through artificial structural engineering. Through deliberate geometrical
design of heterostructures and superlattices, we demonstrate the use of
antiferromagnetic exchange coupling in manipulating the magnetic properties of
the topological surface massive Dirac fermions. This work provides a new
framework on integrating topological insulators with antiferromagnetic
materials and unveils new avenues towards dissipationless topological
antiferromagnetic spintronics.


title:
Constraining minimal anomaly free $\mathrm{U}(1)$ extensions of the
  Standard Model

abstract:
  We consider a class of minimal anomaly free $\mathrm{U}(1)$ extensions of the
Standard Model with three generations of right-handed neutrinos and a complex
scalar. Using electroweak precision constraints, new 13 TeV LHC data, and
considering theoretical limitations such as perturbativity, we show that it is
possible to constrain a wide class of models. By classifying these models with
a single parameter, $\kappa$, we can put a model independent upper bound on the
new $\mathrm{U}(1)$ gauge coupling $g_z$. We find that the new dilepton data
puts strong bounds on the parameters, especially in the mass region
$M_{Z'}\lesssim 3~ \mathrm{TeV}$.


title:
Behavior of luminous matter in the head-on encounter of two ultralight
  BEC dark matter halos

abstract:
  Within the context of ultralight BEC dark matter, we analyze the head-on
encounters of two structures. These structures are made of a BEC component,
which is a ground state equilibrium solution of the Gross-Pitaevskii-Poisson
system, together with a component of luminous matter. The evolution of the
Condensate dark matter is carried out by solving the time dependent GPP
equations, whereas the luminous matter is modeled with particles interacting
gravitationally on top of the BEC dark matter halos. We track the evolution of
frontal encounters for various values of the collision velocity and analyze the
regime of high velocity regime showing solitonic behavior of the BEC halos and
that of slow velocities producing a single final structure. We measure the
relative velocity of the dark matter with respect to the luminous matter after
the encounters in the solitonic case and track the evolution of luminous matter
in the case of merger.


title: Testing CCDM Cosmology with the Radiation Temperature-Redshift Relation

abstract:
  The standard $\Lambda$CDM model can be mimicked at the background and
perturbative levels (linear and non-linear) by a class of gravitationally
induced particle production cosmology dubbed CCDM cosmology. However, the
radiation component in the CCDM model follows a slightly different
temperature-redshift $T(z)$-law which depends on an extra parameter, $\nu_r$,
describing the subdominant photon production rate. Here we perform a
statistical analysis based on a compilation of 36 recent measurements of $T(z)$
at low and intermediate redshifts. The likelihood of the production rate in
CCDM cosmologies is constrained by $\nu_r = 0.024^{+0.026}_{-0.024}$ ($1\sigma$
confidence level), thereby showing that $\Lambda$CDM ($\nu_r=0$) is still
compatible with the adopted data sample. Although being hardly differentiated
in the dynamic sector (cosmic history and matter fluctuations), the so-called
thermal sector (temperature law, abundances of thermal relics and CMB power
spectrum) offers a clear possibility for crucial tests confronting $\Lambda$CDM
and CCDM cosmologies.


title:
Hard X-ray morphology of the X1.3 April 25, 2014 partially occulted limb
  solar flare

abstract:
  At hard X-ray energies, the bright footpoint emission from solar flare loops
often prevents a detailed analysis of the weaker loop-top source morphology due
to the limited dynamic range available for X-ray imaging. Here, we study the
X1.3 April 25, 2014 flare with the Reuven Ramaty High-Energy Solar
Spectroscopic Imager (RHESSI). This partially occulted limb flare allows the
analysis of the loop-top emission in isolation. We present results on the flare
light curve at different energies, the source morphology from X-ray imaging and
a detailed spectral analysis of the different source components by imaging
spectroscopy. The loop-top source, a likely site of particle acceleration,
shows a clear composition of different emission components. The results
indicate the opportunities that detailed imaging of hard X-rays can provide to
learn about particle acceleration, transport and heating processes in solar
flares.


title:
Reducing the Model Order of Deep Neural Networks Using Information
  Theory

abstract:
  Deep neural networks are typically represented by a much larger number of
parameters than shallow models, making them prohibitive for small footprint
devices. Recent research shows that there is considerable redundancy in the
parameter space of deep neural networks. In this paper, we propose a method to
compress deep neural networks by using the Fisher Information metric, which we
estimate through a stochastic optimization method that keeps track of
second-order information in the network. We first remove unimportant parameters
and then use non-uniform fixed point quantization to assign more bits to
parameters with higher Fisher Information estimates. We evaluate our method on
a classification task with a convolutional neural network trained on the MNIST
data set. Experimental results show that our method outperforms existing
methods for both network pruning and quantization.


title: Phase transitions of black holes in massive gravity

abstract:
  In this paper we have studied thermodynamics of a black hole in massive
gravity in the canonical ensemble. The massive gravity theory in consideration
here has a massive graviton due to Lorentz symmetry breaking. The black hole
studied here has a scalar charge due to the massive graviton and is
asymptotically anti-de Sitter. We have computed various thermodynamical
quantities such as temperature, specific heat and free energy. Both the local
and global stability of the black hole are studied by observing the behavior of
the specific heat and the free energy. We have observed that there is a first
order phase transition between small and large black hole for a certain range
of the scalar charge. This phase transition is similar to the liquid/gas phase
transition at constant temperature for a Van der Waals fluid. The coexistence
curves for the small and large black hole branches are also discussed in
detail.


title: The physics of neutrino cross sections: theoretical studies

abstract:
  The present status of neutrino cross section physics is reviewed focusing on
the recent theoretical developments in quasielastic scattering, multi-nucleon
contributions to the inclusive scattering and pion production on nucleons and
nuclei. A good understanding of these processes is crucial to meet the
precision needs of neutrino oscillation experiments. Some of the challenges
that arise in the consistent description of MiniBooNE and MINERvA recent data
are discussed.


title: Engineering the Success of Quantum Walk Search Using Weighted Graphs

abstract:
  Continuous-time quantum walks are natural tools for spatial search, where one
searches for a marked vertex in a graph. Sometimes, the structure of the graph
causes the walker to get trapped, such that the probability of finding the
marked vertex is limited. We give an example with two linked cliques, proving
that the captive probability can be liberated by increasing the weights of the
links. This allows the search to succeed with probability 1 without increasing
the energy scaling of the algorithm. Further increasing the weights, however,
slows the runtime, so the optimal search requires weights that are neither too
weak nor too strong.


title: Free algebras in division rings with an involution

abstract:
  Some general criteria to produce explicit free algebras inside the division
ring of fractions of skew polynomial rings are presented. These criteria are
applied to some special cases of division rings with natural involutions,
yielding, for instance, free subalgebras generated by symmetric elements both
in the division ring of fractions of the group algebra of a torsion free
nilpotent group and in the division ring of fractions of the first Weyl
algebra.


title:
Distributions for tau neutrino interactions observed through the decay
  $\tau\rightarrow \mu\nu_\tau\bar\nu_\mu$

abstract:
  We investigate the problem of identifying $\nu_\tau$-induced reactions in
large neutrino telescopes. We concentrate on events with tracks and showers
where the respective energies $E_\mu$ and $E_X$ are measured separately. Then
we compute analytically and numerically event distributions in two variables
$r_l = E_X/E_l$ and $y'=E_{\text{X}}/(E_{\mu}+E_{X})$. We find that the
$y'$-distribution is especially useful because in the $\nu_\tau$-induced
reactions the distribution has a minimum at $y'=0.75$ and then increases as
$y'\rightarrow1$. This is different in $\nu_\mu$-induced reactions where the
$y'$-distribution decreases monotonically. The results are demonstrated with
figures where one can estimate the required sensitivity of the experiments.
Another attractive property is that in several ratios the neutrino flux
factorizes and drops out. We hope the results of this article will be useful
for searches of tau (anti)neutrinos of energies above 100 GeV to several TeV in
the present and planned large volume neutrino telescopes.


title: A Numerical Scheme for BSVIEs

abstract:
  In this paper, we consider the Euler method for backward stochastic Volterra
integral equations. First, we approximate the original equation by a family of
backward stochastic equations (BSDEs, for short).
  Then we solve the BSDEs by the Euler method. Finally, by virtue of the
numerical solutions to BSDEs, we get the numerical solution to original
equation and obtain the global $1/2$ order convergence speed in $L^2$ norm.


title: Group representations in the homology of 3-manifolds

abstract:
  If M is a manifold with an action of a group G, then the homology group
H_1(M,Q) is naturally a Q[G]-module, where Q[G] denotes the rational group
ring. We prove that for every finite group G, and for every Q[G]-module V,
there exists a closed hyperbolic 3-manifold M with a free G-action such that
the Q[G]-module H_1(M,Q) is isomorphic to V. We give an application to spectral
geometry: for every finite set P of prime numbers, there exist hyperbolic
3-manifolds N and N' that are strongly isospectral such that for all p in P,
the p-power torsion subgroups of H_1(N,Z) and of H_1(N',Z) have different
orders. We also show that, in a certain precise sense, the rational homology of
oriented Riemannian 3-manifolds with a G-action "knows" nothing about the fixed
point structure under G, in contrast to the 2-dimensional case. The main
geometric techniques are Dehn surgery and, for the spectral application, the
Cheeger-M\"uller formula, but we also make use of tools from different branches
of algebra, most notably of regulator constants, a representation theoretic
tool that was originally developed in the context of elliptic curves.


title: The near-to-mid infrared spectrum of quasars

abstract:
  We analyse a sample of 85 luminous (log(nuLnu(3\um)/erg s-1)>45.5) quasars
with restframe ~2-11 \um spectroscopy from AKARI and Spitzer. Their high
luminosity allows a direct determination of the near-infrared quasar spectrum
free from host galaxy emission. A semi-empirical model consisting of a single
template for the accretion disk and two blackbodies for the dust emission
successfully reproduces the 0.1-10 \um spectral energy distributions (SEDs).
Excess emission at 1-2 \um over the best-fitting model suggests that hotter
dust is necessary in addition to the ~1200 K blackbody and the disk to
reproduce the entire near-infrared spectrum. Variation in the extinction
affecting the disk and in the relative strength of the disk and dust components
accounts for the diversity of individual SEDs. Quasars with higher dust-to-disk
luminosity ratios show slightly redder infrared continua and less prominent
silicate emission. We find no luminosity dependence in the shape of the average
infrared quasar spectrum. We generate a new quasar template that covers the
restframe range 0.1-11 \um, and separate templates for the disk and dust
components. Comparison with other infrared quasar composites suggests that
previous ones are less reliable in the 2-4 \um range. Our template is the first
one to provide a detailed view of the infrared emission on both sides of the 4
\um bump.


title:
An extensive spectroscopic time-series of three Wolf-Rayet stars. I. The
  lifetime of large-scale structures in the wind of WR 134

abstract:
  During the summer of 2013, a 4-month spectroscopic campaign took place to
observe the variabilities in three Wolf-Rayet stars. The spectroscopic data
have been analyzed for WR 134 (WN6b), to better understand its behaviour and
long-term periodicity, which we interpret as arising from corotating
interaction regions (CIRs) in the wind. By analyzing the variability of the He
II $\lambda$5411 emission line, the previously identified period was refined to
P = 2.255 $\pm$ 0.008 (s.d.) days. The coherency time of the variability, which
we associate with the lifetime of the CIRs in the wind, was deduced to be 40
$\pm$ 6 days, or $\sim$ 18 cycles, by cross-correlating the variability
patterns as a function of time. When comparing the phased observational
grayscale difference images with theoretical grayscales previously calculated
from models including CIRs in an optically thin stellar wind, we find that two
CIRs were likely present. A separation in longitude of $\Delta \phi \simeq$
90$^{\circ}$ was determined between the two CIRs and we suggest that the
different maximum velocities that they reach indicate that they emerge from
different latitudes. We have also been able to detect observational signatures
of the CIRs in other spectral lines (C IV $\lambda\lambda$5802,5812 and He I
$\lambda$5876). Furthermore, a DAC was found to be present simultaneously with
the CIR signatures detected in the He I $\lambda$5876 emission line which is
consistent with the proposed geometry of the large-scale structures in the
wind. Small-scale structures also show a presence in the wind, simultaneously
with the larger scale structures, showing that they do in fact co-exist.


title: QUBIC Experiment

abstract:
  QUBIC is a ground-based experiment, currently under construction, that uses
the novel bolometric interferometry technology. It is dedicated to measure the
primordial B-modes of CMB. As a bolometric interferometer, QUBIC has high
sensitivity and good systematics control. Dust contamination is controlled by
operating with two bands -- 150 and 220 GHz. There are two possible sites for
QUBIC: either Concordia station in Antarctic or in the Argentinian Puna desert.
It is planned to see the first light in 2018-2019.


title: t-multiple discrete logarithm problem and solving difficulty

abstract:
  Considering the difficult problem under classical computing model can be
solved by the quantum algorithm in polynomial time, t-multiple discrete
logarithm problems presented. The problem is non-degeneracy and unique
solution. We talk about what the parameter effects the problem solving
difficulty. Then we pointed out that the index-calculus algorithm is not
suitable for the problem, and two sufficient conditions of resistance to the
quantum algorithm for the hidden subgroup problem are given.


title: Inflation model building with an accurate measure of e-folding

abstract:
  It has become standard practice to take the logarithmic growth of the scale
factor as a measure of the amount of inflation, despite the well-known fact
that this is only an approximation for the true amount of inflation required to
solve the horizon and flatness problems. The aim of this work is to show how
this approximation can be completely avoided using an alternative framework for
inflation model building. We show that using the inverse Hubble radius as the
key dynamical parameter, the correct number of e-folding arises naturally as a
measure of inflation. As an application, we present an interesting model in
which the entire inflationary dynamics can be solved analytically and exactly,
and, in special cases, reduces to the familiar class of power-law models.


title:
Dynamics of Air Transport Networks: A Review from a Complex Systems
  Perspective

abstract:
  Air transport systems are highly dynamic at temporal scales from minutes to
years. This dynamic behavior not only characterizes the evolution of the system
but also affect the system's functioning. Understanding the evolutionary
mechanisms is thus fundamental in order to better design optimal air transport
networks that benefits companies, passengers and the environment. In this
review, we briefly present and discuss the state-of-art on time-evolving air
transport networks. We distinguish the structural analysis of sequences of
network snapshots, ideal for long-term network evolution (e.g. annual
evolution), and temporal paths, preferred for short-term dynamics (e.g. hourly
evolution). We emphasize that most previous research focused on the first
modeling approach (i.e. long-term) whereas only a few studies look at
high-resolution temporal paths. We conclude the review highlighting that much
research remains to be done, both to apply already available methods and to
develop new measures for temporal paths on air transport networks. In
particular, we identify that the study of delays, network resilience and
optimization of resources (aircraft and crew) are critical topics that can
benefit of temporal network analysis.


title: Relativistic Quantum Dynamics on a Double Cone

abstract:
  In this paper, we study the relativistic quantum problem of a particle
constrained to a double cone surface. For this purpose, we build the Dirac
equation in a curved space using the tetrads formalism. Two cases are analysed.
First, we consider a free particle on a double cone surface, and then we add an
uniform magnetic field. The energy spectrum is obtained and the instability of
the motion is discussed. We show that the magnetic field breaks the nappe
degeneracy, inducing different energy spectra for each nappe. The results
obtained here can be applied, for instance, in he investigation of the
electronic and transport properties of condensed matter systems that can be
described by an effective Dirac equation, such as graphene and topological
insulators.


title:
Gearbox Fault Detection through PSO Exact Wavelet Analysis and SVM
  Classifier

abstract:
  Time-frequency methods for vibration-based gearbox faults detection have been
considered the most efficient method. Among these methods, continuous wavelet
transform (CWT) as one of the best time-frequency method has been used for both
stationary and transitory signals. Some deficiencies of CWT are problem of
overlapping and distortion ofsignals. In this condition, a large amount of
redundant information exists so that it may cause false alarm or
misinterpretation of the operator. In this paper a modified method called Exact
Wavelet Analysis is used to minimize the effects of overlapping and distortion
in case of gearbox faults. To implement exact wavelet analysis, Particle Swarm
Optimization (PSO) algorithm has been used for this purpose. This method have
been implemented for the acceleration signals from 2D acceleration sensor
acquired by Advantech PCI-1710 card from a gearbox test setup in Amirkabir
University of Technology. Gearbox has been considered in both healthy and
chipped tooth gears conditions. Kernelized Support Vector Machine (SVM) with
radial basis functions has used the extracted features from exact wavelet
analysis for classification. The efficiency of this classifier is then
evaluated with the other signals acquired from the setup test. The results show
that in comparison of CWT, PSO Exact Wavelet Transform has better ability in
feature extraction in price of more computational effort. In addition, PSO
exact wavelet has better speed comparing to Genetic Algorithm (GA) exact
wavelet in condition of equal population because of factoring mutation and
crossover in PSO algorithm. SVM classifier with the extracted features in
gearbox shows very good results and its ability has been proved.


title:
On thermodynamic inconsistencies in several photosynthetic and solar
  cell models and how to fix them

abstract:
  We analyze standard theoretical models of solar energy conversion developed
to study solar cells and photosynthetic systems. We show that the assumption
that the energy transfer to the reaction center/electric circuit is through a
decay rate or "sink", is in contradiction with the second law of
thermodynamics. We put forward a thermodynamically consistent alternative by
explicitly considering parts of the reaction center/electric circuit and by
employing a Hamiltonian transfer. The predicted energy transfer by the new
scheme differs from the one found using a decay rate, casting doubts on the
validity of the conclusions obtained by models which include the latter.


title: Simulation of the Internet of Things

abstract:
  This paper presents main concepts and issues concerned with the simulation of
Internet of Things (IoT). The heterogeneity of possible scenarios, arising from
the massive deployment of an enormous amount of sensors and devices, imposes
the use of sophisticated modeling and simulation techniques. In fact, the
simulation of IoT introduces several issues from both quantitative and
qualitative aspects. We discuss novel simulation techniques to enhance
scalability and to permit the real-time execution of massively populated IoT
environments (e.g., large-scale smart cities). In particular, we claim that
agent-based, adaptive Parallel and Distributed Simulation (PADS) approaches are
needed, together with multi-level simulation, which provide means to perform
highly detailed simulations, on demand. We present a use case concerned with
the simulation of smart territories.


title: Borel version of the Local Lemma

abstract:
  We prove a Borel version of the local lemma, i.e. we show that, under
suitable assumptions, if the set of variables in the local lemma has a
structure of a Borel space, then there exists a satisfying assignment which is
a Borel function. The main tool which we develop for the proof, which is of
independent interest, is a parallel version of the Moser-Tardos algorithm which
uses the same random bits to resample clauses that are far enough in the
dependency graph.


title:
A Tracer Method for Computing Type Ia Supernova Yields: Burning Model
  Calibration, Reconstruction of Thickened Flames, and Verification for Planar
  Detonations

abstract:
  We refine our previously introduced parameterized model for explosive
carbon-oxygen fusion during thermonuclear supernovae (SN Ia) by adding
corrections to post-processing of recorded Lagrangian fluid element histories
to obtain more accurate isotopic yields. Deflagration and detonation products
are verified for propagation in a uniform density medium. A new method is
introduced for reconstructing the temperature-density history within the
artificially thick model deflagration front. We obtain better than 5\%
consistency between the electron capture computed by the burning model and
yields from post-processing. For detonations, we compare to a benchmark
calculation of the structure of driven steady-state planar detonations
performed with a large nuclear reaction network and error-controlled
integration. We verify that, for steady-state planar detonations down to a
density of 5x10^6 g/cc, our post processing matches the major abundances in the
benchmark solution typically to better than 10% for times greater than 0.01 s
after the shock front passage. As a test case to demonstrate the method,
presented here with post-processing for the first time, we perform a two
dimensional simulation of a SN Ia in the Chandrasekhar-mass
deflagration-detonation transition (DDT) scenario. We find that reconstruction
of deflagration tracks leads to slightly more complete silicon burning than
without reconstruction. The resulting abundance structure of the ejecta is
consistent with inferences from spectroscopic studies of observed SNe Ia. We
confirm the absence of a central region of stable Fe-group material for the
multi-dimensional DDT scenario. Detailed isotopic yields are tabulated and only
change modestly when using deflagration reconstruction.


title:
Thermodynamics at the microscale: from effective heating to the Brownian
  Carnot engine

abstract:
  We review a series of experimental studies of the thermodynamics of
nonequilibrium processes at the microscale. In particular, in these experiments
we studied the fluctuations of the thermodynamic properties of a single
optically-trapped microparticle immersed in water and in the presence of
external random forces. In equilibrium, the fluctuations of the position of the
particle can be described by an effective temperature that can be tuned up to
thousands of Kelvins. Isothermal and non-isothermal thermodynamic processes
that also involve changes in a control parameter were implemented by
controlling the effective temperature of the particle and the stiffness of the
optical trap. Since truly adiabatic processes are unfeasible in colloidal
systems, mean adiabatic protocols where no average heat is exchanged between
the particle and the environment are discussed and implemented. By
concatenating isothermal and adiabatic protocols, it is shown how a
single-particle Carnot engine can be constructed. Finally, we provide an
in-depth study of the fluctuations of the energetics and of the efficiency of
the cycle.


title: A microscopic model for chemically-powered Janus motors

abstract:
  Very small synthetic motors that make use of chemical reactions to propel
themselves in solution hold promise for new applications in the development of
new materials, science and medicine. The prospect of such potential
applications, along with the fact that systems with many motors or active
elements display interesting cooperative phenomena of fundamental interest, has
made the study of synthetic motors an active research area. Janus motors,
comprising catalytic and noncatalytic hemispheres, figure prominently in
experimental and theoretical studies of these systems. While continuum models
of Janus particle systems are often used to describe motor dynamics,
microscopic models that are able to account for intermolecular interactions,
many-body concentration gradients, fluid flows and thermal fluctuations provide
a way to explore the dynamical behavior of these complex out-of-equilibrium
systems that does not rely on approximations that are often made in continuum
theories. The analysis of microscopic models from first principles provides a
foundation from which the range of validity and limitations of approximate
theories of the dynamics may be assessed. In this paper, a microscopic model
for the diffusiophoretic propulsion of Janus motors, where motor interactions
with the environment occur only through hard collisions, is constructed,
analyzed and compared to theoretical predictions. Microscopic simulations of
both single-motor and many-motor systems are carried out to illustrate the
results.


title: Racah matrices and hidden integrability in evolution of knots

abstract:
  We construct a general procedure to extract the exclusive Racah matrices S
and \bar S from the inclusive 3-strand mixing matrices by the evolution method
and apply it to the first simple representations R =[1], [2], [3] and [2,2].
The matrices S and \bar S relate respectively the maps (R\otimes R)\otimes \bar
R\longrightarrow R with R\otimes (R \otimes \bar R) \longrightarrow R and
(R\otimes \bar R) \otimes R \longrightarrow R with R\otimes (\bar R \otimes R)
\longrightarrow R. They are building blocks for the colored HOMFLY polynomials
of arbitrary arborescent (double fat) knots. Remarkably, the calculation
realizes an unexpected integrability property underlying the evolution
matrices.


title:
Transference of Bilinear Restriction Estimates to Quadratic Variation
  Norms and the Dirac-Klein-Gordon System

abstract:
  Firstly, bilinear Fourier Restriction estimates --which are well-known for
free waves-- are extended to adapted spaces of functions of bounded quadratic
variation, under quantitative assumptions on the phase functions. This has
applications to nonlinear dispersive equations, in particular in the presence
of resonances. Secondly, critical global well-posedness and scattering results
for massive Dirac-Klein-Gordon systems in dimension three are obtained, in
resonant as well as in non-resonant regimes. The results apply to small initial
data in scale-invariant Sobolev spaces exhibiting a small amount of angular
regularity.


title: Ultracold chemical reactions of a single Rydberg atom in a dense gas

abstract:
  Within a dense environment ($\rho \approx 10^{14}\,$atoms/cm$^3$) at
ultracold temperatures ($T < 1\,\mu{}\text{K}$), a single atom excited to a
Rydberg state acts as a reaction center for surrounding neutral atoms. At these
temperatures almost all neutral atoms within the Rydberg orbit are bound to the
Rydberg core and interact with the Rydberg atom. We have studied the reaction
rate and products for $nS$ $^{87}$Rb Rydberg states and we mainly observe a
state change of the Rydberg electron to a high orbital angular momentum $l$,
with the released energy being converted into kinetic energy of the Rydberg
atom. Unexpectedly, the measurements show a threshold behavior at $n\approx
100$ for the inelastic collision time leading to increased lifetimes of the
Rydberg state independent of the densities investigated. Even at very high
densities ($\rho\approx4.8\times 10^{14}\,\text{cm}^{-3}$), the lifetime of a
Rydberg atom exceeds $10\,\mu\text{s}$ at $n > 140$ compared to
$1\,\mu\text{s}$ at $n=90$. In addition, a second observed reaction mechanism,
namely Rb$_2^+$ molecule formation, was studied. Both reaction products are
equally probable for $n=40$ but the fraction of Rb$_2^+$ created drops to below
10$\,$% for $n\ge90$.


title:
Kappa-symmetry of superstring sigma model and generalized 10d
  supergravity equations

abstract:
  We determine the constraints imposed on the 10d target superspace geometry by
the requirement of classical kappa-symmetry of the Green-Schwarz superstring.
In the type I case we find that the background must satisfy a generalization of
type I supergravity equations. These equations depend on an arbitrary vector
X_a and imply the one-loop scale invariance of the GS sigma model. In the
special case when X_a is the gradient of a scalar \phi (dilaton) one recovers
the standard type I equations equivalent to the 2d Weyl invariance conditions
of the superstring sigma model. In the type II case we find a generalized
version of the 10d supergravity equations the bosonic part of which was
introduced in arXiv:1511.05795. These equations depend on two vectors \X_a and
K_a subject to 1st order differential relations (with the equations in the
NS-NS sector depending only on the combination X_a = \X_a + K_a). In the
special case of K_a=0 one finds that \X_a=\d_a \phi and thus obtains the
standard type II supergravity equations. New generalized solutions are found if
K_a is chosen to be a Killing vector (and thus they exist only if the metric
admits an isometry). Non-trivial solutions of the generalized equations
describe K-isometric backgrounds that can be mapped by T-duality to type II
supergravity solutions with dilaton containing a linear isometry-breaking term.
Examples of such backgrounds appeared recently in the context of integrable
\eta-deformations of AdS_n x S^n sigma models. The classical kappa-symmetry
thus does not, in general, imply the 2d Weyl invariance conditions for the GS
sigma model (equivalent to type II supergravity equations) but only weaker
scale invariance type conditions.


title: Doubly cvharged vector leptons and the Higgs portal

abstract:
  Using a bottom up phenomenological approach we constructed a simple doubly
charged vector lepton $E^{\pm\pm}$ model for the possible 750 GeV diphoton
resonance $\Phi$ at the LHC assuming it to be a scalar particle. Since no
stable doubly charged leptons are seen, to facilitate their decays we complete
the model by adding a charged SM electroweak scalar $S^\pm$. $\Phi$ is a SM
singlet and can be either an inert scalar or a Higgs field. In the inert case
more than one vector lepton are required to account for the photon fusion
production of the resonance if the model is to remain perturbative. For a
Higgssed case $S^\pm$ can assist the production mechanism without using more
than one such lepton. We also found that precision measurements constrain the
couplings of $E^{\pm\pm}$ and $S^\pm$ to SM particles to be small. This raises
the possibility that they can be fairly long lived and can give rise to
displaced vertices if produced at the LHC.


title:
The Derivation and Approximation of Coarse-grained Dynamics from
  Langevin Dynamics

abstract:
  We present a derivation of a coarse-grained model from the Langevin dynamics.
The focus is placed on the memory kernel function and the
fluctuation-dissipation theorem. Also presented is an hierarchy of
approximations for the memory and random noise terms, using rational
approximations in the Laplace domain. These approximations offer increasing
accuracy. More importantly, they eliminate the need to evaluate the integral
associated with the memory term at each time step.


title: From Boole to Leggett-Garg: Epistemology of Bell-type Inequalities

abstract:
  In 1862, George Boole derived an inequality for variables, now known as
Boolean variables, that in his opinion represents a demarcation line between
possible and impossible experience. This inequality forms an important
milestone in the epistemology of probability theory and probability measures.
  In 1985 Leggett and Garg derived a physics related inequality, mathematically
identical to Boole's, that according to them represents a demarcation between
macroscopic realism and quantum mechanics. Their formalism, constructed for the
magnetic flux of SQUIDS, includes general features and applies also to many
other quantum experiments.
  We show that a wide gulf, a wide divide, separates the "sense impressions"
and corresponding data, as well as the postulates of macroscopic realism, from
the mathematical abstractions that are used to derive the inequality of
Leggett-Garg. If the gulf can be bridged, one may indeed derive the said
inequality, which is then clearly a demarcation between possible and impossible
experience: it cannot be violated and is not violated by quantum theory. We
deduce from this fact that a violation of the Leggett-Garg inequality does not
mean that the SQUID-flux is not there when nobody looks, as Leggett-Garg
suggest, but instead that the probability measures may not be what Leggett-Garg
have assumed them to be, when no data can be secured that directly relate to
them. We show that similar considerations apply to other well known quantum
interpretation-puzzles including that of the two-slit experiment.


title: On the Exact Interpolating Function in ABJ Theory

abstract:
  Based on the recent indications of integrability in the planar ABJ model, we
conjecture an exact expression for the interpolating function
h(\lambda_1,\lambda_2) in this theory. Our conjecture is based on the
observation that the integrability structure of the ABJM theory given by its
Quantum Spectral Curve is very rigid and does not allow for a simple consistent
modification. Under this assumption, we revised the previous comparison of
localization results and exact all loop integrability calculations done for the
ABJM theory by one of the authors and Grigory Sizov, fixing
h(\lambda_1,\lambda_2). We checked our conjecture against various weak coupling
expansions, at strong coupling and also demonstrated its invariance under the
Seiberg-like duality. This match also gives further support to the
integrability of the model. If our conjecture is correct, it extends all the
available integrability results in the ABJM model to the ABJ model.


title: Counterfactual Definiteness and Bell's Inequality

abstract:
  Counterfactual definiteness must be used as at least one of the postulates or
axioms that are necessary to derive Bell-type inequalities. It is considered by
many to be a postulate that is not only commensurate with classical physics (as
for example Einstein's special relativity), but also separates and
distinguishes classical physics from quantum mechanics. It is the purpose of
this paper to show that Bell's choice of mathematical functions and independent
variables implicitly includes counterfactual definiteness and reduces the
generality of the physics of Bell-type theories so significantly that no
meaningful comparison of these theories with actual Einstein-Podolsky-Rosen
experiments can be made.


title:
Product of simplices and sets of positive upper density in
  $\mathbb{R}^d$

abstract:
  We establish that any subset of $\mathbb{R}^d$ of positive upper Banach
density necessarily contains an isometric copy of all sufficiently large
dilates of any fixed two-dimensional rectangle provided $d\geq4$.
  We further present an extension of this result to configurations that are the
product of two non-degenerate simplices; specifically we show that if
$\Delta_{k_1}$ and $\Delta_{k_2}$ are two fixed non-degenerate simplices of
$k_1+1$ and $k_2+1$ points respectively, then any subset of $\mathbb{R}^d$ of
positive upper Banach density with $d\geq k_1+k_2+6$ will necessarily contain
an isometric copy of all sufficiently large dilates of
$\Delta_{k_1}\times\Delta_{k_2}$.
  A new direct proof of the fact that any subset of $\mathbb{R}^d$ of positive
upper Banach density necessarily contains an isometric copy of all sufficiently
large dilates of any fixed non-degenerate simplex of $k+1$ points provided
$d\geq k+1$, a result originally due to Bourgain, is also presented.


title:
Microcavity design for low threshold polariton condensation with
  ultrashort optical pulse excitation

abstract:
  We present a microcavity structure with a shifted photonic stop-band to
enable efficient non-resonant injection of a polariton condensate with
spectrally broad femtosecond pulses. The concept is demonstrated theoretically
and confirmed experimentally for a planar GaAs/AlGaAs multilayer
heterostructure pumped with ultrashort near-infrared pulses while
photoluminescence is collected to monitor the optically injected polariton
density. As the excitation wavelength is scanned, a regime of polariton
condensation can be reached in our structure at a consistently lower fluence
threshold than in a state-of-the-art conventional microcavity. Our microcavity
design improves the polariton injection efficiency by a factor of 4, as
compared to a conventional microcavity design, when broad excitation pulses are
centered at a wavelength of 740 nm. Most remarkably, this improvement factor
reaches 270 when the excitation wavelength is centered at 750 nm.


title:
Observations of spatiotemporal instabilities in the strong-driving
  regime of an AC-driven nonlinear Schr\"odinger system

abstract:
  Localized dissipative structures (LDS) have been predicted to display a rich
array of instabilities, yet systematic experimental studies have remained
scarce. We have used a synchronously-driven optical fiber ring resonator to
experimentally study LDS instabilities in the strong-driving regime of the
AC-driven nonlinear Schr\"odinger equation (also known as the Lugiato-Lefever
model). Through continuous variation of a single control parameter, we have
observed a string of theoretically predicted instability modes, including
irregular oscillations and chaotic collapses. Beyond a critical point, we
observe behaviour reminiscent of a phase transition: LDSs trigger localized
domains of spatiotemporal chaos that invade the surrounding homogeneous state.
Our findings directly confirm a number of theoretical predictions, and they
highlight that complex LDS instabilities can play a role in experimental
systems.


title: Randomized Matrix-free Trace and Log-Determinant Estimators

abstract:
  We present randomized algorithms for estimating the trace and deter- minant
of Hermitian positive semi-definite matrices. The algorithms are based on
subspace iteration, and access the matrix only through matrix vector products.
We analyse the error due to randomization, for starting guesses whose elements
are Gaussian or Rademacher random variables. The analysis is cleanly separated
into a structural (deterministic) part followed by a probabilistic part. Our
absolute bounds for the expectation and concentration of the estimators are
non-asymptotic and informative even for matrices of low dimension. For the
trace estimators, we also present asymptotic bounds on the number of samples
(columns of the starting guess) required to achieve a user-specified relative
error. Numerical experiments illustrate the performance of the estimators and
the tightness of the bounds on low-dimensional matrices; and on a challenging
application in uncertainty quantification arising from Bayesian optimal
experimental design.