title: Harmonic Oscillators and Elementary Particles

abstract:
  Two dynamical systems with same symmetry should have features in common, and
as far as their shared symmetry is concerned, one may represent the other. The
three light quark constituents of the hadrons, a) have an approximate flavor
SU(3) symmetry, b) have an exact color SU(3) symmetry, and c) as spin 1/2
particles, have a Lorentz SO(3,1) symmetry. So does a 3D harmonic oscillator.
a) Its Hamiltonian has the SU(3) symmetry, breakable if the 3 fundamental modes
of oscillation are not identical. b) The 3 directions of oscillation have the
permutation symmetry. This enables one to create three copies of unbreakable
SU(3) symmetry for each mode of the oscillation, and mimic the color of the
elementary particles. And c) The Lagrangian of the 3D oscillator has the
SO(3,1) symmetry. This can be employed to accommodate the spin of the
particles. In this paper we draw up a one-to-one correspondence between the
eigen modes of the Poisson bracket operator of the 3D oscillator and the flavor
multiplets of the particles, and between the permuted modes of the oscillator
and the color and anticolor multiplets of the particles. Gluons are represented
by the generators of the color SU(3) symmetry of the oscillator. Harmonic
oscillators are common place objects and, wherever encountered, are
analytically solvable. Elementary particles, on the other hand, are abstract
entities far from one's reach. Understanding of one may help a better
appreciation of the other.


title: 3D Single-port Labyrinthine Acoustic Metamaterial

abstract:
  In this paper, we report on the design, fabrication, and experimental
characterization of a 3D single-port labyrinthine acoustic metamaterial. By
using curled perforations with one end closed and with appropriate loss inside,
the proposed metamaterial can perfectly absorb airborne sounds in a low
frequency band. Both the position and width of the band can be tuned flexibly.
A tradeoff is uncovered between the relative absorption bandwidth and thickness
of the metamaterial. When the relative absorption bandwidth is as high as 51%,
the requirement of deep subwavelength thickness (0.07{\lambda}) can still be
satisfied.


title: Lebesgue measure of escaping sets of entire functions

abstract:
  For a transcendental entire function $f$ of finite order in the
Eremenko-Lyubich class $\mathcal{B}$, we give conditions under which the
Lebesgue measure of the escaping set $\mathcal{I}(f)$ of $f$ is zero. This is
inspired by the recent work of Aspenberg and Bergweiler, in which they give
conditions on entire functions in the same class with escaping sets of positive
Lebesgue measure. We will construct an entire function in the Eremenko-Lyubich
class to show that the condition given by Aspenberg and Bergweiler is
essentially sharp. Furthermore, we adapt our idea of proof to the case of
infinite order entire functions. Under some restrictions to the growth of these
entire functions, we show that the escaping sets have zero Lebesgue measure.
This generalizes a result of Eremenko and Lyubich.


title:
Advanced fluid modelling and PIC/MCC simulations of low-pressure ccrf
  discharges

abstract:
  Comparative studies of capacitively coupled radio-frequency discharges in
helium and argon at pressures between 10 and 80 Pa are presented applying two
different fluid modelling approaches as well as two independently developed
particle-in-cell/Monte Carlo collision (PIC/MCC) codes. The focus is on the
analysis of the range of applicability of a recently proposed fluid model
including an improved drift-diffusion approximation for the electron component
as well as its comparison with fluid modelling results using the classical
drift-diffusion approximation and benchmark results obtained by PIC/MCC
simulations. Main features of this time- and space-dependent fluid model are
given. It is found that the novel approach shows generally quite good agreement
with the macroscopic properties derived by the kinetic simulations and is
largely able to characterize qualitatively and quantitatively the discharge
behaviour even at conditions when the classical fluid modelling approach fails.
Furthermore, the excellent agreement between the two PIC/MCC simulation codes
using the velocity Verlet method for the integration of the equations of motion
verifies their accuracy and applicability.


title: Heavy Weyl fermion state in CeRu$_4$Sn$_6$

abstract:
  A new type of topological state in strongly corrected condensed matter
systems, heavy Weyl fermion state, has been found in a heavy fermion material
CeRu$_4$Sn$_6$, which has no inversion symmetry. Both two different types of
Weyl points, type I and II, can be found in the quasi-particle band structure
obtained by the LDA+Guztwiller calculations, which can treat the strong
correlation effects among the f-electrons from Cerium atoms. The surface
calculations indicate that the topologically protected Fermi arc states exist
on the (010) but not on the (001) surfaces.


title:
Convergence Relative to a Microstructure : Properties, Optimal Bounds
  and Application

abstract:
  In this work, we study a new notion involving convergence of microstructures
represented by matrices $B^\epsilon$ related to the classical $H$-convergence
of $A^\epsilon$. It incorporates the interaction between the two
microstructures. This work is about its effects on various aspects : existence,
examples, optimal bounds on emerging macro quantities, application etc. Five
among them are highlighted below : $(1)$ The usual arguments based on
translated inequality, $H$-measures, Compensated Compactness etc for obtaining
optimal bounds are not enough. Additional compactness properties are needed.
$(2)$ Assuming two-phase microstructures, the bounds define naturally four
optimal regions in the phase space of macro quantities. The classically known
single region in the self-interacting case , namely $B^\epsilon= A^\epsilon$
can be recovered from them, a result that indicates we are dealing with a true
extension of the $\mathcal{G}$-closure problem. $(3)$ Optimality of the bounds
is not immediate because of (a priori) non-commutativity of macro-matrices, an
issue not present in the self-interacting case. Somewhat surprisingly though,
commutativity follows a posteriori. $(4)$ From the application to "Optimal
Oscillation-Dissipation Problems", it emerges that oscillations and dissipation
can co-exist optimally and the microstructures behind them need not be the same
though they are closely linked. Furthermore, optimizers are found among
$N$-rank laminates with interfaces. This is a new feature. $(5)$ Explicit
computations in the case of canonical microstructures are performed, in which
we make use of $H$-measure in a novel way.


title: A generalised multicomponent system of Camassa-Holm-Novikov equations

abstract:
  In this paper we introduce a two-component system, depending on a parameter
$b$, which generalises the Camassa-Holm ($b=1$) and Novikov equations ($b=2$).
By investigating its Lie algebra of classical and higher symmetries up to order
$3$, we found that for $b\neq 2$ the system admits a $3$-dimensional algebra of
point symmetries and apparently no higher symmetries, whereas for $b=2$ it has
a $6$-dimensional algebra of point symmetries and also higher order symmetries.
Also we provide all conservation laws, with first order characteristics, which
are admitted by the system for $b=1,2$. In addition, for $b=2$, we show that
the system is a particular instance of a more general system which admits an
$\mathfrak{sl}(3,\mathbb{R})$-valued zero-curvature representation. Finally, we
found that the system admits peakon solutions and, in particular, for $b=2$
there exist 1-peakon solutions with non-constant amplitude.


title:
A computational study of particle deposition patterns from a circular
  laminar jet

abstract:
  Particle deposition patterns on the plate of inertial impactor with circular
laminar jet are investigated numerically with a Lagrangian solver implemented
within the framework of the OpenFOAM$^{\circledR}$ CFD package. Effects of
taper angle of the nozzle channel and jet-to-plate distance are evaluated. The
results show that tapered nozzle tends to deposit more particles toward the
circular spot edge than straight nozzle. At jet Reynolds number $Re = 1132$, a
tapered nozzle deposits particles to form a pattern with a high density ring
toward the deposition spot edge, especially for particle Stokes number $St >
St_{50}$, which is absent with a straight nozzle. Increasing the jet-to-plate
distance tends to reduce the value of particle density peak near deposition
spot edge. Reducing $Re$ to $283$ (e.g., for $300$ ccm flow through a $1.5$ mm
diameter jet nozzle) yields particle deposition patterns without the high
density ring at the deposition spot edge when the same tapered nozzle is used.
The particle deposition patterns with the straight nozzle at $Re = 283$ exhibit
further reduced particle density around the spot edge such that the particle
density profile appears more or less like a Gaussian function. In general, the
effect of reducing $Re$ on particle deposition pattern seems to be similar to
increasing the jet-to-plate distance. The computed particle deposition
efficiency $\eta$ shows the fact that very fine particles with extremely small
values of $St$ near the jet axis always impact the center of plate, indicating
that the value of $\eta$ does not approach zero with a substantial reduction of
$St$. Such a "small particle contamination" typically amounts to $\sim 10\%$ of
small particles (with $\sqrt{St} < 0.1$) at $Re \sim 1000$ and $\sim 5\%$ at
$Re \sim 300$, which may not be negligible in data analysis with inertial
impactor measurement.


title:
A definite recursive relation and some statistical properties for
  M\"obius function

abstract:
  An elementary recursive relation for M$\ddot{\mathrm{o}}$bius function $\mu
(n)$ is introduced by two simple ways. With this recursive relation, $\mu (n)$
can be calculated without directly knowing the factorization of the $n$. $\mu
(1) \sim \mu (2 \times 10^7) $ are calculated recursively one by one. Based on
these $2\times 10^7$ samples, the empirical probabilities of $\mu (n)$ of
taking $-1$, 0, and 1 in classic statistics are calculated and compared with
the theoretical probabilities in number theory. The numerical consistency
between these two kinds of probability show that $\mu (n)$ could be seen as an
independent random sequence when $n$ is large. The expectation and variance of
the $\mu (n)$ are $0$ and $6 n/ \pi^2$, respectively. Furthermore, we show that
any conjecture of the Mertens type is false in probability sense, and present
an upper bound for cumulative sums of $\mu (n)$ with a certain probability.


title:
Transport of phase space densities through tetrahedral meshes using
  discrete flow mapping

abstract:
  Discrete flow mapping was recently introduced as an efficient ray based
method determining wave energy distributions in complex built up structures.
Wave energy densities are transported along ray trajectories through polygonal
mesh elements using a finite dimensional approximation of a ray transfer
operator. In this way the method can be viewed as a smoothed ray tracing method
defined over meshed surfaces. Many applications require the resolution of wave
energy distributions in three-dimensional domains, such as in room acoustics,
underwater acoustics and for electromagnetic cavity problems. In this work we
extend discrete flow mapping to three-dimensional domains by propagating wave
energy densities through tetrahedral meshes. The geometric simplicity of the
tetrahedral mesh elements is utilised to efficiently compute the ray transfer
operator using a mixture of analytic and spectrally accurate numerical
integration. The important issue of how to choose a suitable basis
approximation in phase space whilst maintaining a reasonable computational cost
is addressed via low order local approximations on tetrahedral faces in the
position coordinate and high order orthogonal polynomial expansions in momentum
space.


title: Exploring quantum teleportation through unitary error bases

abstract:
  Unitary error bases have a great number of applications across quantum
information and quantum computation, and are fundamentally linked to quantum
teleportation, dense coding and quantum error correction. Werner's
combinatorial construction builds a unitary error basis from a family of
Hadamard matrices and a Latin square. In this dissertation, I give a new
categorical axiomatisation of Latin squares, and use this to give a fully
graphical presentation and proof of the correctness of Werner's construction.
The categorical approach makes clear that some of the Latin square axioms are
unnecessary for the construction to go through, and I propose a generalised
construction scheme with the potential to create new classes of unitary error
bases.


title: Hilbert scheme of twisted cubics as simple wall-crossing

abstract:
  We study the Hilbert scheme of twisted cubics in the three-dimensional
projective space by using Bridgeland stability conditions. We use wall-crossing
techniques to describe its geometric structure and singularities, which
reproves the classical result of Piene and Schlessinger.


title: On the Weak Solutions to Mixed Navier-Stokes-Darcy Model

abstract:
  In this paper, an a priori estimate of weak solutions to the mixed
Navier-Stokes/Darcy model with Beavers-Joseph-Saffman's interface condition and
the existence of a weak solution are established without the small data and/or
the large viscosity restriction for the first time. Based on these results, the
global uniqueness of the weak solution is obtained.


title: HARPS3 for a Roboticized Isaac Newton Telescope

abstract:
  We present a description of a new instrument development, HARPS3, planned to
be installed on an upgraded and roboticized Isaac Newton Telescope by end-2018.
HARPS3 will be a high resolution (R = 115,000) echelle spectrograph with a
wavelength range from 380-690 nm. It is being built as part of the Terra
Hunting Experiment - a future 10 year radial velocity measurement programme to
discover Earth-like exoplanets. The instrument design is based on the
successful HARPS spectrograph on the 3.6m ESO telescope and HARPS-N on the TNG
telescope. The main changes to the design in HARPS3 will be: a customised fibre
adapter at the Cassegrain focus providing a stabilised beam feed and on-sky
fibre diameter ~ 1.4 arcsec, the implementation of a new continuous flow
cryostat to keep the CCD temperature very stable, detailed characterisation of
the HARPS3 CCD to map the effective pixel positions and thus provide an
improved accuracy wavelength solution, an optimised integrated polarimeter and
the instrument integrated into a robotic operation. The robotic operation will
optimise our programme which requires our target stars to be measured on a
nightly basis. We present an overview of the entire project, including a
description of our anticipated robotic operation.


title:
Guaranteed upper and lower bounds on the uniform load of contact
  problems in elasticity

abstract:
  Two mathematical models are developed within the theoretical framework of
large strain elasticity for the determination of upper and lower bounds on the
total strain energy of a finitely deformed hyperelastic body in unilateral
contact with a rigid surface or with an elastic substrate. The model problems
take the form of two continuous optimization problems with inequality
constraints, the solutions of which are used to provide an enclosure on the
uniform external load acting on the body's surface away from the contact zone.


title:
Consequences of simultaneous chiral symmetry breaking and deconfinement
  for the isospin symmetric phase diagram

abstract:
  The thermodynamic bag model (tdBag) has been applied widely to model quark
matter properties in both heavy-ion and astrophysics communities. Several
fundamental physics aspects are missing in tdBag, e.g., dynamical chiral
symmetry breaking (D$\chi$SB) and repulsions due to the vector interaction are
both included explicitly in the novel vBag quark matter model of Kl\"ahn and
Fischer (2015) (Astrophys. J. 810, 134 (2015)). An important feature of vBag is
the simultaneous D$\chi$SB and deconfinement, where the latter links vBag to a
given hadronic model for the construction of the phase transition. In this
article we discuss the extension to finite temperatures and the resulting phase
diagram for the isospin symmetric medium.


title:
Vertex positions of the generalized orthocenter and a related elliptic
  curve

abstract:
  We study triangles $ABC$ and points $P$ for which the generalized orthocenter
$H$ corresponding to $P$ coincides with a vertex $A,B$, or $C$. The set of all
such points $P$ is a union of three ellipses minus $6$ points. In addition, if
$T_P$ is the affine map taking $ABC$ to the cevian triangle $DEF$ of $P$ with
respect to $ABC$, $P'$ is the isotomic conjugate of $P$, and $T_{P'}$ is the
affine map taking $ABC$ to the cevian triangle of $P'$, then we study the locus
of points $P$ for which the map $\textsf{M}_P=T_p \circ K^{-1} \circ T_{P'}$ is
a translation. Here, $K$ is the complement map for $ABC$, and $\textsf{M}_P$ is
an affine map taking the circumconic of $ABC$ for $P$ to the inconic of $ABC$
for $P$. The locus in question turns out to be an elliptic curve minus $6$
points, which can be synthetically constructed using the geometry of the
triangle.


title:
Scalable Modeling of Multivariate Longitudinal Data for Prediction of
  Chronic Kidney Disease Progression

abstract:
  Prediction of the future trajectory of a disease is an important challenge
for personalized medicine and population health management. However, many
complex chronic diseases exhibit large degrees of heterogeneity, and
furthermore there is not always a single readily available biomarker to
quantify disease severity. Even when such a clinical variable exists, there are
often additional related biomarkers routinely measured for patients that may
better inform the predictions of their future disease state. To this end, we
propose a novel probabilistic generative model for multivariate longitudinal
data that captures dependencies between multivariate trajectories. We use a
Gaussian process based regression model for each individual trajectory, and
build off ideas from latent class models to induce dependence between their
mean functions. We fit our method using a scalable variational inference
algorithm to a large dataset of longitudinal electronic patient health records,
and find that it improves dynamic predictions compared to a recent state of the
art method. Our local accountable care organization then uses the model
predictions during chart reviews of high risk patients with chronic kidney
disease.


title:
Finding the Dark Hole with the Lights On: A New Approach to Focal Plane
  Wavefront Sensing

abstract:
  In direct imaging of exoplanets from space, achieving the required dynamic
range (i.e., planet-to-star contrast in brightness) currently relies on
coronagraphic technology combined with active control of one or more deformable
mirrors (DMs) to create a dark region in the image plane, sometimes called a
"dark hole." While many algorithms have been proposed for this purpose, all of
them employ focal plane wavefront sensing (FPWS) in order to calculate the
optimal DM configuration to create the desired dark hole. All current
algorithms are limited by their own success in that, as the dark hole is
achieved, the FPWS procedure becomes shot-noise limited due to he low intensity
in the dark hole. This article proposes a FPWS procedure that allows
determination of the optimal DM configuration without relying on information
obtained when the DM is near the optimal configuration. This article gives
regression procedures for FPWS that do not assume the DM step size is small,
which should allow two important improvements to the control loop: 1)
performing informative FPWS observations with DM configurations that are
sufficiently distant from the optimal dark hole configuration to mitigate
shot-noise limitations, and 2) more accurately predicting the DM configuration
that will achieve the desired objective in the dark hole control loop. In order
to treat this more challenging FPWS problem, two different representations are
presented. The first of these, is called the empirical Green's function (EGF),
is easy to implement, and has a block-diagonal matrix structure that is
well-suited to parallel processing. The other representation, based on an
explicit aberration expansion (EAE) requires the regression to estimate a
smaller number of parameters than the EGF, but leads to a dense matrix
structure. The EGF and EAE methods both simultaneously estimate the planetary
image.


title:
The magnetic moments and electromagnetic form factors of the decuplet
  baryons in chiral perturbation theory

abstract:
  We have systematically investigated the magnetic moments and magnetic form
factors of the decuplet baryons to the next-to-next-leading order in the
framework of the heavy baryon chiral perturbation theory. Our calculation
includes the contributions from both the intermediate decuplet and octet baryon
states in the loops. We also calculate the charge and magnetic dipole form
factors of the decuplet baryons. Our results may be useful to the chiral
extrapolation of the lattice simulations of the decuplet electromagnetic
properties.


title: Non-Hermitian engineering of single mode two dimensional laser arrays

abstract:
  A new scheme for building two dimensional laser arrays that operate in the
single supermode regime is proposed. This is done by introducing an optical
coupling between the laser array and a lossy pseudo-isospectral chain of
photonic resonators. The spectrum of this discrete reservoir is tailored to
suppress all the supermodes of the main array except the fundamental one. This
spectral engineering is facilitated by employing the Householder transformation
in conjunction with discrete supersymmetry. The proposed scheme is general and
can in principle be used in different platforms such as VCSEL arrays and
photonic crystal laser arrays.


title:
Effects of gauge boson mass on chiral and deconfinement phase
  transitions in QED$_{3}$

abstract:
  Based on the experimental observation that there is a coexisting region
between the antiferromagnetic (AF) and $\textit{d}$-wave superconducting
($\textit{d}$SC) phases, the influences of gauge boson mass $m_{a}$ on chiral
symmetry restoration and deconfinement phase transitions in QED$_{3}$ are
investigated simultaneously within a unified framework, i.e., Dyson-Schwinger
equations. The results show that the chiral symmetry restoration phase
transition in the presence of the gauge boson mass $m_{a}$ is a typical
second-order phase transition; the chiral symmetry restoration and
deconfinement phase transitions are coincident; the critical number of fermion
flavors $N^{c}_{f}$ decreases as the gauge boson mass $m_{a}$ increases and
there exists a boundary that separates the $N^{c}_{f}$-$m_{a}$ plane into
chiral symmetry breaking/confinement region for ($N_{f}^{c}$, $m_{a}$) below
the boundary and chiral symmetry restoration/deconfinement region for
($N_{f}^{c}$, $m_{a}$) above it.


title: Banjo Rim Height and Sound in the Pot

abstract:
  Rim and back geometry determine much of the behavior of sound inside the pot,
whose effect on total, produced sound is subtle but discernible. The theory of
sound inside a cylinder is reviewed and demonstrated. And previous work on the
Helmholtz resonance and the interplay between the Helmholtz resonance and the
lowest head mode is revisited using some improved techniques.


title: Optimal importance sampling for L\'evy Processes

abstract:
  We develop generic and efficient importance sampling estimators for Monte
Carlo evaluation of prices of single- and multi-asset European and
path-dependent options in asset price models driven by L\'evy processes,
extending earlier works which focused on the Black-Scholes and continuous
stochastic volatility models. Using recent results from the theory of large
deviations on the path space for processes with independent increments, we
compute an explicit asymptotic approximation for the variance of the pay-off
under an Esscher-style change of measure. Minimizing this asymptotic variance
using convex duality, we then obtain an easy to compite asymptotically
efficient importance sampling estimator of the option price. Numerical tests
for European baskets and for Asian options in the variance gamma model show
consistent variance reduction with a very small computational overhead.


title:
Training Echo State Networks with Regularization through Dimensionality
  Reduction

abstract:
  In this paper we introduce a new framework to train an Echo State Network to
predict real valued time-series. The method consists in projecting the output
of the internal layer of the network on a space with lower dimensionality,
before training the output layer to learn the target task. Notably, we enforce
a regularization constraint that leads to better generalization capabilities.
We evaluate the performances of our approach on several benchmark tests, using
different techniques to train the readout of the network, achieving superior
predictive performance when using the proposed framework. Finally, we provide
an insight on the effectiveness of the implemented mechanics through a
visualization of the trajectory in the phase space and relying on the
methodologies of nonlinear time-series analysis. By applying our method on well
known chaotic systems, we provide evidence that the lower dimensional embedding
retains the dynamical properties of the underlying system better than the
full-dimensional internal states of the network.


title: Ray and wave scattering in smoothly curved thin shell cylindrical ridges

abstract:
  We propose wave and ray approaches for modelling mid- and high- frequency
structural vibrations through smoothed joints on thin shell cylindrical ridges.
The models both emerge from a simplified classical shell theory setting. The
ray model is analysed via an appropriate phase-plane analysis, from which the
fixed points can be interpreted in terms of the reflection and transmission
properties. The corresponding full wave scattering model is studied using the
finite difference method to investigate the scattering properties of an
incident plane wave. Through both models we uncover the scattering properties
of smoothed joints in the interesting mid-frequency region close to the ring
frequency, where there is a qualitative change in the dynamics from anisotropic
to simple geodesic propagation.


title:
Secondary radiation measurements for particle therapy applications:
  Charged secondaries produced by 4He and 12C ion beams in a PMMA target at
  large angle

abstract:
  Measurements performed with the purpose of characterizing the charged
secondary radiation for dose release monitoring in particle therapy are
reported. Charged secondary yields, energy spectra and emission profiles
produced in poly-methyl methacrylate (PMMA) target by 4He and 12C beams of
different therapeutic energies were measured at 60 and 90 degree with respect
to the primary beam direction. The secondary yields of protons produced along
the primary beam path in PMMA target were obtained. The energy spectra of
charged secondaries were obtained from time-of-flight information, whereas the
emission profiles were reconstructed exploiting tracking detector information.
The measured charged secondary yields and emission profiles are in agreement
with the results reported in literature and confirm the feasibility of ion beam
therapy range monitoring using 12C ion beam. The feasibility of range
monitoring using charged secondary particles is also suggested for 4He ion
beam.


title: A proof of the Gaudin Bethe Ansatz conjecture

abstract:
  Gaudin algebra is the commutative subalgebra in $U(\mathfrak{g})^{\otimes N}$
generated by higher integrals of the quantum Gaudin magnet chain attached to a
semisimple Lie algebra $\mathfrak{g}$. This algebra depends on a collection of
pairwise distinct complex numbers $z_1,\ldots,z_N$. We prove that this
subalgebra has a cyclic vector in the space of singular vectors of the tensor
product of any finite-dimensional irreducible $\mathfrak{g}$-modules, for all
values of the parameters $z_1,\ldots,z_N$. We deduce from this result the Bethe
Ansatz conjecture in the Feigin-Frenkel form which states that the joint
eigenvalues of the higher Gaudin Hamiltonians on the tensor product of
irreducible finite-dimensional $\mathfrak{g}$-modules are in 1-1 correspondence
with monodromy-free ${}^LG$-opers on the projective line with regular
singularities at the points $z_1,\ldots,z_N,\infty$ and the prescribed residues
at the singular points.


title: Structuring polymer gels via catalytic reactions

abstract:
  We use computer simulations to investigate how a catalytic reaction in a
polymer sol can induce the formation of a polymer gel. To this aim we consider
a solution of homopolymers in which freely-diffusing catalysts convert the
originally repulsive A monomers into attractive B ones. We find that at low
temperatures this reaction transforms the polymer solution into a physical gel
that has a remarkably regular mesostructure in the form of a cluster phase,
absent in the usual homopolymer gels obtained by a quench in temperature. We
investigate how this microstructuring depends on catalyst concentration,
temperature, and polymer density and show that the dynamics for its formation
can be understood in a semi-quantitative manner using the interaction
potentials between the particles as input. The structuring of the copolymers
and the AB sequences resulting from the reactions can be discussed in the
context of the phase behaviour of correlated random copolymers. The location of
the spinodal line as found in our simulations is consistent with analytical
predictions. Finally, we show that the observed structuring depends not only on
the chemical distribution of the A and B monomers but also on the mode of
formation of this distribution.


title:
Nilpotent Symmetries of a Model of 2D Diffeomorphism Invariant Theory:
  BRST Approach

abstract:
  Within the framework of Becchi-Rouet-Stora-Tyutin (BRST) formalism, we
discuss the full set of proper BRST and anti-BRST transformations for a 2D
diffeomorphism invariant theory which is described by the Lagrangian density of
a standard bosonic string. The above (anti-)BRST transformations are off-shell
nilpotent and absolutely anticommuting. The latter property is valid on a
submanifold of the space of the quantum fields where the 2D version of the
universal (anti-)BRST invariant Curci-Ferrari (CF) type of restrictions are
satisfied. We derive the precise forms of the BRST and anti-BRST invariant
Lagrangian densities as well as the exact expressions for the conserved
(anti-)BRST and ghost charges. The lucid derivation of the proper anti-BRST
symmetry transformations and the emergence of the CF-type restrictions are
completely novel results for our present bosonic string which has already been
discussed earlier in literature where only the BRST symmetry transformations
have been pointed out. We briefly mention the derivation of the CF-type
restrictions from the modified version of Bonora-Tonin superfield approach,
too.


title:
Jets or vortices - what flows are generated by an inverse turbulent
  cascade?

abstract:
  An inverse cascade - energy transfer to progressively larger scales - is a
salient feature of two-dimensional turbulence. If the cascade reaches the
system scale, it creates a coherent flow expected to have the largest available
scale and conform with the symmetries of the domain. In a doubly periodic
rectangle, the mean flow with zero total momentum was therefore believed to be
unidirectional, with two jets along the short side; while for an aspect ratio
close to unity, a vortex dipole was expected. Using direct numerical
simulations, we show that in fact neither the box symmetry is respected nor the
largest scale is realized: the flow is never purely unidirectional since the
inverse cascade produces coherent vortices, whose number and relative motion
are determined by the aspect ratio. This spontaneous symmetry breaking is
closely related to the hierarchy of averaging times. Long-time averaging
restores translational invariance due to vortex wandering along one direction,
and gives jets whose profile, however, can be deduced neither from the
largest-available-scale argument, nor from the often employed maximum-entropy
principle or quasi-linear approximation.

categories: nlin.CD astro-ph.EP cond-mat.stat-mech physics.ao-ph physics.flu-dyn


title:
Characteristic temperature for the immiscible-miscible transition of
  binary condensates in optical lattices

abstract:
  We study a two-species Bose-Einstein condensates confined in
quasi-two-dimensional (quasi-2D) optical lattices at finite temperatures,
employing the Hartree-Fock-Bogoliubov theory with the Popov approximation. We
examine the role of thermal fluctuations on the ground-state density
distributions, and the quasiparticle mode evolution. At zero temperature, the
geometry of the ground-state in the immiscible domain is side-by-side. Our
results show that the thermal fluctuations enhance the miscibility of the
condensates, and at a characteristic temperature the system becomes miscible
with rotationally symmetric overlapping density profiles. This
immiscible-miscible transition is accompanied by a discontinuity in the
excitation spectrum, and the low-lying quasiparticle modes such as slosh mode
becomes degenerate at the characteristic temperature.


title:
Magnetic Yoking and Tunable Interactions in FePt-Based Hard/Soft
  Bilayers

abstract:
  Assessing and controlling magnetic interactions in magnetic nanostructures
are critical to nanomagnetic and spintronic explorations, such as magnetic
recording media, permanent magnets, magnetic memory and logic devices, etc.
Here we demonstrate an extremely sensitive magnetic yoking effect and tunable
interactions in FePt based hard/soft bilayers mediated by the soft layer. Below
the exchange length, a thin soft layer strongly exchange couples to the
perpendicular moments of the hard layer; above the exchange length, just a few
nanometers thicker, the soft layer moments turn in-plane and act to yoke the
dipolar fields from the adjacent hard layer perpendicular domains. The
evolution from exchange to dipolar-dominated interactions is experimentally
captured by first-order reversal curves, the delta-M method, and polarized
neutron reflectometry, and confirmed by micromagnetic simulations. These
findings demonstrate an effective yoking approach to design and control
magnetic interactions in wide varieties of magnetic nanostructures and devices.


title: Neural versus Phrase-Based Machine Translation Quality: a Case Study

abstract:
  Within the field of Statistical Machine Translation (SMT), the neural
approach (NMT) has recently emerged as the first technology able to challenge
the long-standing dominance of phrase-based approaches (PBMT). In particular,
at the IWSLT 2015 evaluation campaign, NMT outperformed well established
state-of-the-art PBMT systems on English-German, a language pair known to be
particularly hard because of morphology and syntactic differences. To
understand in what respects NMT provides better translation quality than PBMT,
we perform a detailed analysis of neural versus phrase-based SMT outputs,
leveraging high quality post-edits performed by professional translators on the
IWSLT data. For the first time, our analysis provides useful insights on what
linguistic phenomena are best modeled by neural models -- such as the
reordering of verbs -- while pointing out other aspects that remain to be
improved.


title:
Optimized auxiliary representation of a non-Markovian environment by a
  Lindblad equation

abstract:
  We present a general scheme to map correlated nonequilibrium quantum impurity
problems onto an auxiliary open quantum system of small size. The infinite
fermionic reservoirs of the original system are thereby replaced by a small
number $N_B$ of noninteracting auxiliary bath sites whose dynamics is described
by a Lindblad equation. Due to the presence of the intermediate bath sites, the
overall dynamics acting on the impurity site is non-Markovian.
  With the help of an optimization scheme for the auxiliary Lindblad
parameters, an accurate mapping is achieved, which becomes exponentially exact
upon increasing $N_B$. The basic idea for this scheme was presented previously
in the context of nonequilibrium dynamical mean field theory. In successive
works on improved manybody solution strategies for the auxiliary Lindblad
equation, such as Lanczos exact diagonalization or matrix product states, we
applied the approach to study the nonequilibrium Kondo regime.
  In the present paper, we address in detail the mapping procedure itself,
rather than the many-body solution. In particular, we investigate the effects
of the geometry of the auxiliary system on the accuracy of the mapping for
given $N_B$. Specifically, we present a detailed convergence study for five
different geometries which, besides being of practical utility, reveals
important insights into the underlying mechanisms of the mapping. For setups
with onsite or nearest-neighbor Lindblad parameters we find that a
representation adopting two separate bath chains is by far more accurate with
respect to other choices based on a single chain or a commonly used star
geometry. A significant improvement is obtained by allowing for long-ranged and
complex Lindblad parameters. These results can be of great value when studying
Lindblad-type approaches to correlated systems.


title:
Flow Ambiguity: A Path Towards Classically Driven Blind Quantum
  Computation

abstract:
  Blind quantum computation protocols allow a user to delegate a computation to
a remote quantum computer in such a way that the privacy of their computation
is preserved, even from the device implementing the computation. To date, such
protocols are only known for settings involving at least two quantum devices:
either a user with some quantum capabilities and a remote quantum server or two
or more entangled but noncommunicating servers. In this work, we take the first
step towards the construction of a blind quantum computing protocol with a
completely classical client and single quantum server. Specifically, we show
how a classical client can exploit the ambiguity in the flow of information in
measurement-based quantum computing to construct a protocol for hiding critical
aspects of a computation delegated to a remote quantum computer. This ambiguity
arises due to the fact that, for a fixed graph, there exist multiple choices of
the input and output vertex sets that result in deterministic measurement
patterns consistent with the same fixed total ordering of vertices. This allows
a classical user, computing only measurement angles, to drive a
measurement-based computation performed on a remote device while hiding
critical aspects of the computation.


title:
Thermodynamic limit and boundary energy of the SU(3) spin chain with
  non-diagonal boundary fields

abstract:
  We investigate the thermodynamic limit of the su(n)-invariant spin chain
models with unparallel boundary fields. It is found that the contribution of
the inhomogeneous term in the associated T-Q relation to the ground state
energy does vanish in the thermodynamic limit. This fact allows us to calculate
the boundary energy of the system. Taking the su(2) (or the XXX) spin chain and
the su(3) spin chain as concrete examples, we have studied the corresponding
boundary energies of the models. The method used in this paper can be
generalized to study the thermodynamic properties and boundary energy of other
high rank models with non-diagonal boundary fields.


title: Topology of the space of locally convex curves on the 3-sphere

abstract:
  A (positive) locally convex curve in the 2-sphere is a curve with positive
geodesic curvature (i.e., which always turns left). In the 3-sphere, it is a
curve with positive torsion. In this work we discussed the topology of spaces
of such curves with prescribed initial and final jets. The case of the 2-sphere
is understood (Saldanha-2013); the case of n=3 is not yet thoroughly clarified.
In order to obtain partial information about the homotopy type of such spaces
in the case n=3, we represented a positive locally convex curve as a pair of
curves on the 2-sphere with some restrictions.


title:
Linear Convergence of Gradient and Proximal-Gradient Methods Under the
  Polyak-\L{}ojasiewicz Condition

abstract:
  In 1963, Polyak proposed a simple condition that is sufficient to show a
global linear convergence rate for gradient descent. This condition is a
special case of the \L{}ojasiewicz inequality proposed in the same year, and it
does not require strong convexity (or even convexity). In this work, we show
that this much-older Polyak-\L{}ojasiewicz (PL) inequality is actually weaker
than the main conditions that have been explored to show linear convergence
rates without strong convexity over the last 25 years. We also use the PL
inequality to give new analyses of randomized and greedy coordinate descent
methods, sign-based gradient descent methods, and stochastic gradient methods
in the classic setting (with decreasing or constant step-sizes) as well as the
variance-reduced setting. We further propose a generalization that applies to
proximal-gradient methods for non-smooth optimization, leading to simple proofs
of linear convergence of these methods. Along the way, we give simple
convergence results for a wide variety of problems in machine learning: least
squares, logistic regression, boosting, resilient backpropagation,
L1-regularization, support vector machines, stochastic dual coordinate ascent,
and stochastic variance-reduced gradient methods.


title: Higher-Order Kullback-Leibler Aggregation of Markov Chains

abstract:
  We consider the problem of reducing a first-order Markov chain on a large
alphabet to a higher-order Markov chain on a small alphabet. We present
information-theoretic cost functions that are related to predictability and
lumpability, show relations between these cost functions, and discuss
heuristics to minimize them. Our experiments suggest that the generalization to
higher orders is useful for model reduction in reliability analysis and natural
language processing.


title:
Finite size effects for spacing distributions in random matrix theory:
  circular ensembles and Riemann zeros

abstract:
  According to Dyson's three fold way, from the viewpoint of global time
reversal symmetry there are three circular ensembles of unitary random matrices
relevant to the study of chaotic spectra in quantum mechanics. These are the
circular orthogonal, unitary and symplectic ensembles, denoted COE, CUE and CSE
respectively. For each of these three ensembles and their thinned versions,
whereby each eigenvalue is deleted independently with probability $1-\xi$, we
take up the problem of calculating the first two terms in the scaled large $N$
expansion of the spacing distributions. It is well known that the leading term
admits a characterisation in terms of both Fredholm determinants and Painlev\'e
transcendents. We show that modifications of these characterisations also
remain valid for the next to leading term, and that they provide schemes for
high precision numerical computations. In the case of the CUE there is an
application to the analysis of Odlyzko's data set for the Riemann zeros, and in
that case some further statistics are similarly analysed.


title: Arrangements of homothets of a convex body

abstract:
  Answering a question of F\"uredi and Loeb (1994), we show that the maximum
number of pairwise intersecting homothets of a $d$-dimensional centrally
symmetric convex body $K$, none of which contains the center of another in its
interior, is at most $O(3^d d\log d)$. If $K$ is not necessarily centrally
symmetric and the role of its center is played by its centroid, then the above
bound can be replaced by $O(3^d\binom{2d}{d}d\log d)$. We establish analogous
results for the case where the center is defined as an arbitrary point in the
interior of $K$. We also show that in the latter case, one can always find
families of at least $\Omega((2/\sqrt{3})^d)$ translates of $K$ with the above
property.


title:
Giant Spin Gap and Magnon Localization in the Disordered Heisenberg
  Antiferromagnet Sr2Ir1-xRuxO4

abstract:
  We study the evolution of magnetic excitations in the disordered
two-dimensional antiferromagnet Sr2Ir1-xRuxO4. A gigantic magnetic gap greater
than 40 meV opens at x = 0.27 and increases with Ru concentration, rendering
the dispersive magnetic excitations in Sr2IrO4 almost momentum independent. Up
to a Ru concentration of x = 0.77, both experiments and first-principles
calculations show the Ir Jeff = 1/2 state remains intact. The magnetic gap
arises from the local interaction anisotropy in the proximity of the Ru
disorder. Under the coherent potential approximation, we reproduce the
experimental magnetic excitations using the disordered Heisenberg
antiferromagnetic model with suppressed next-nearest neighbor ferromagnetic
coupling.


title: Genuine Cosmic Hair

abstract:
  We show that asymptotically future deSitter (AFdS) spacetimes carry 'genuine'
cosmic hair; information that is analogous to the mass and angular momentum of
asymptotically flat spacetimes and that characterizes how an AFdS spacetime
approaches its asymptotic form. We define new 'cosmological tension' charges
associated with future asymptotic spatial translation symmetries, which are
analytic continuations of the ADM mass and tensions of asymptotically planar
AdS spacetimes, and which measure the leading anisotropic corrections to the
isotropic, exponential deSitter expansion rate. A cosmological Smarr relation,
holding for AFdS spacetimes having exact spatial translation symmetry, is
derived. This formula relates cosmological tension, which is evaluated at
future infinity, to properties of the cosmology at early times, together with a
'cosmological volume' contribution that is analogous to the thermodynamic
volume of AdS black holes. Smarr relations for different spatial directions
imply that the difference in expansion rates between two directions at late
times is related in a simple way to their difference at early times. Hence
information about the very early universe can be inferred from cosmic hair,
which is potentially observable in a late time deSitter phase. Cosmological
tension charges and related quantities are evaluated for Kasner-deSitter
spacetimes, which serve as our primary examples.


title: Temporally Consistent Motion Segmentation from RGB-D Video

abstract:
  We present a method for temporally consistent motion segmentation from RGB-D
videos assuming a piecewise rigid motion model. We formulate global energies
over entire RGB-D sequences in terms of the segmentation of each frame into a
number of objects, and the rigid motion of each object through the sequence. We
develop a novel initialization procedure that clusters feature tracks obtained
from the RGB data by leveraging the depth information. We minimize the energy
using a coordinate descent approach that includes novel techniques to assemble
object motion hypotheses. A main benefit of our approach is that it enables us
to fuse consistently labeled object segments from all RGB-D frames of an input
sequence into individual 3D object reconstructions.


title:
Spectrophotometric properties of dwarf planet Ceres from the VIR
  spectrometer on board the Dawn mission

abstract:
  We study the spectrophotometric properties of dwarf planet Ceres in the
VIS-IR spectral range by means of hyper-spectral images acquired by the VIR
imaging spectrometer on board the NASA Dawn mission. Disk-resolved observations
with a phase angle within the $7^{\circ}<\alpha<132^{\circ}$ interval were used
to characterize Ceres' phase curve in the 0.465-4.05 $\mu$m spectral range.
Hapke's model was applied to perform the photometric correction of the dataset,
allowing us to produce albedo and color maps of the surface. The $V$-band
magnitude phase function of Ceres was fitted with both the classical linear
model and H-G formalism. The single-scattering albedo and the asymmetry
parameter at 0.55$\mu$m are $w=0.14\pm0.02$ and $\xi=-0.11\pm0.08$,
respectively (two-lobe Henyey-Greenstein phase function); the modeled geometric
albedo is $0.094\pm0.007$; the roughness parameter is
$\bar{\theta}=29^{\circ}\pm6^{\circ}$. Albedo maps indicate small variability
on a global scale with an average reflectance of $0.034 \pm 0.003$. Isolated
areas such as the Occator bright spots, Haulani, and Oxo show an albedo much
higher than average. We measure a significant spectral phase reddening, and the
average spectral slope of Ceres' surface after photometric correction is
$1.1\%k\AA^{-1}$ and $0.85\%k\AA^{-1}$ at VIS and IR wavelengths, respectively.
Broadband color indices are $V-R=0.38\pm0.01$ and $R-I=0.33\pm0.02$. H-G
modeling of the $V$-band magnitude phase curve for $\alpha<30^{\circ}$ gives
$H=3.14\pm0.04$ and $G=0.10\pm0.04$, while the classical linear model provides
$V(1,1,0^{\circ})=3.48\pm0.03$ and $\beta=0.036\pm0.002$. The comparison with
spectrophotometric properties of other minor bodies indicates that Ceres has a
less back-scattering phase function and a slightly higher albedo than comets
and C-type objects. However, the latter represents the closest match in the
usual asteroid taxonomy.


title: Towards Evaluating the Robustness of Neural Networks

abstract:
  Neural networks provide state-of-the-art results for most machine learning
tasks. Unfortunately, neural networks are vulnerable to adversarial examples:
given an input $x$ and any target classification $t$, it is possible to find a
new input $x'$ that is similar to $x$ but classified as $t$. This makes it
difficult to apply neural networks in security-critical areas. Defensive
distillation is a recently proposed approach that can take an arbitrary neural
network, and increase its robustness, reducing the success rate of current
attacks' ability to find adversarial examples from $95\%$ to $0.5\%$.
  In this paper, we demonstrate that defensive distillation does not
significantly increase the robustness of neural networks by introducing three
new attack algorithms that are successful on both distilled and undistilled
neural networks with $100\%$ probability. Our attacks are tailored to three
distance metrics used previously in the literature, and when compared to
previous adversarial example generation algorithms, our attacks are often much
more effective (and never worse). Furthermore, we propose using high-confidence
adversarial examples in a simple transferability test we show can also be used
to break defensive distillation. We hope our attacks will be used as a
benchmark in future defense attempts to create neural networks that resist
adversarial examples.


title:
Three-dimensional Doppler, polarization-gradient, and magneto-optical
  forces for atoms and molecules with dark states

abstract:
  We theoretically investigate the damping and trapping forces in a
three-dimensional magneto-optical trap (MOT), by numerically solving the
optical Bloch equations. We focus on the case where there are dark states
because the atom is driven on a "type-II" system where the angular momentum of
the excited state, $F'$, is less than or equal to that of the ground state,
$F$. For these systems we find that the force in a three-dimensional light
field has very different behaviour to its one dimensional counterpart. This
differs from the more commonly used "type-I" systems ($F'=F+1$) where the 1D
and 3D behaviours are similar. Unlike type-I systems where, for red-detuned
light, both Doppler and sub-Doppler forces damp the atomic motion towards zero
velocity, in type-II systems in 3D, the Doppler force and polarization gradient
force have opposite signs. As a result, the atom is driven towards a non-zero
equilibrium velocity, $v_{0}$, where the two forces cancel. We find that
$v_{0}^{2}$ scales linearly with the intensity of the light and is fairly
insensitive to the detuning from resonance. We also discover a new
magneto-optical force that alters the normal MOT force at low magnetic fields
and whose influence is greatest in the type-II systems. We discuss the
implications of these findings for the laser cooling and magneto-optical
trapping of molecules where type-II transitions are unavoidable in realising
closed optical cycling transitions.


title:
Saturation effects in low-x DIS structure functions and related hadronic
  total cross sections

abstract:
  High-energy nucleon total cross sections are related to low-x DIS structure
functions by using the additive quark model.


title: Enabling Factor Analysis on Thousand-Subject Neuroimaging Datasets

abstract:
  The scale of functional magnetic resonance image data is rapidly increasing
as large multi-subject datasets are becoming widely available and
high-resolution scanners are adopted. The inherent low-dimensionality of the
information in this data has led neuroscientists to consider factor analysis
methods to extract and analyze the underlying brain activity. In this work, we
consider two recent multi-subject factor analysis methods: the Shared Response
Model and Hierarchical Topographic Factor Analysis. We perform analytical,
algorithmic, and code optimization to enable multi-node parallel
implementations to scale. Single-node improvements result in 99x and 1812x
speedups on these two methods, and enables the processing of larger datasets.
Our distributed implementations show strong scaling of 3.3x and 5.5x
respectively with 20 nodes on real datasets. We also demonstrate weak scaling
on a synthetic dataset with 1024 subjects, on up to 1024 nodes and 32,768
cores.


title:
Atomic force microscopy reconstruction of complex-shaped chiral
  plasmonic nanostructures

abstract:
  A significant part of the optical metamaterial phenomena has the plasmonic
nature and their investigation requires very accurate knowledge of the
fabricated structures shape with a focus on the periodical features. We
describe a consistent approach to the shape reconstruction of the plasmonic
nanostructures. This includes vertical and tilted spike AFM probes fabrication,
AFM imaging and specific post-processing. We studied a complex-shaped chiral
metamaterial and conclude that the described post-processing routine extends
possibilities of the existing deconvolution algorithms in the case of
periodical structures with known rotational symmetry, by providing valuable
information about periodical features.


title: Relative Igusa-Todorov functions and relative homological dimensions

abstract:
  We develope the theory of the $\mathcal{E}$-relative Igusa-Todorov functions
in an exact $ IT$-context $(\mathcal{C},\mathcal{E}).$ In the case when
$\mathcal{C}=$mod$\, (\Lambda)$ is the category of finitely generated left
$\Lambda$-modules, for an artin algebra $\Lambda,$ and $\mathcal{E}$ is the
class of all exact sequences in $\mathcal{C},$ we recover the usual
Igusa-Todorov functions. We use the setting of the exact structures and the
Auslander-Solberg relative homological theory to generalise the original
Igusa-Todorov's results. Furthermore, we introduce the $\mathcal{E}$-relative
Igusa-Todorov dimension and also we obtain relationships with the relative
global and relative finitistic dimensions and the Gorenstein homological
dimensions.


title: Exponents of operator self-similar random fields

abstract:
  If X(c^E t) and c^H X(t) have the same finite-dimensional distributions for
some linear operators E and H, we say that the random vector field X(t) is
operator self-similar. The exponents E and H are not unique in general, due to
symmetry. This paper characterizes the possible set of range exponents H for a
given domain exponent, and conversely, the set of domain exponents E for a
given range exponent.


title: Quiver elliptic W-algebras

abstract:
  We define elliptic generalization of W-algebras associated with arbitrary
quiver using the formalism of arXiv:1512.08533 applied to six-dimensional
quiver gauge theory compactified on elliptic curve.


title:
Study of movement coordination in human ensembles via a novel
  computer-based set-up

abstract:
  Movement coordination in human ensembles has been studied little in the
current literature. In the existing experimental works, situations where all
subjects are connected with each other through direct visual and auditory
coupling, and social interaction affects their coordination, have been
investigated. Here, we study coordination in human ensembles via a novel
computer-based set-up that enables individuals to coordinate each other's
motion from a distance so as to minimize the influence of social interaction.
The proposed platform makes it possible to implement different visual
interaction patterns among the players, so that participants take into
consideration the motion of a designated subset of the others. This allows the
evaluation of the exclusive effects on coordination of the structure of
interconnections among the players and their own dynamics. Our set-up enables
also the deployment of virtual players to investigate dyadic interaction
between a human and a virtual agent, as well as group synchronization in mixed
teams of human and virtual agents. We use this novel set-up to study
coordination both in dyads and in groups over different structures of
interconnections, with and without virtual agents. We find that, in dual
interaction, virtual players manage to interact with participants in a
human-like fashion, thus confirming findings in previous work. We also observe
that, in group interaction, the level of coordination among humans in the
absence of direct visual and auditory coupling depends on the structure of
interconnections among participants. This confirms, as recently suggested in
the literature, that different coordination levels are achieved over diverse
visual pairings in the presence and in the absence of social interaction. We
present preliminary experimental results on the effect on group coordination of
deploying virtual computer agents in the human ensemble.

categories: cs.HC physics.data-an physics.soc-ph q-bio.NC


title: Homes' law in Holographic Superconductor with Q-lattices

abstract:
  Homes' law, $\rho_s = C \sigma_{\mathrm{DC}} T_c$, is an empirical law
satisfied by various superconductors with a material independent universal
constant $C$, where $\rho_{s}$ is the superfluid density at zero temperature,
$T_c$ is the critical temperature, and $\sigma_{\mathrm{DC}}$ is the electric
DC conductivity in the normal state close to $T_c$. We study Homes' law in
holographic superconductor with Q-lattices and find that Homes' law is realized
for some parameter regime in insulating phase near the metal-insulator
transition boundary, where momentum relaxation is strong. In computing the
superfluid density, we employ two methods: one is related to the infinite DC
conductivity and the other is related to the magnetic penetration depth. With
finite momentum relaxation both yield the same results, while without momentum
relaxation only the latter gives the superfluid density correctly because the
former has a spurious contribution from the infinite DC conductivity due to
translation invariance.


title:
Differential and Integral Calculus for Logical Operations. A
  Matrix-Vector Approach

abstract:
  A variety of problems emerged investigating electronic circuits, computer
devices and cellular automata motivated a number of attempts to create a
differential and integral calculus for Boolean functions. In the present
article, we extend this kind of calculus in order to include the semantic of
classical logical operations. We show that this extension to logics is strongly
helped if we submerge the elementary logical calculus in a matrix-vector
formalism that naturally includes a kind of fuzzy-logic. In this way, guided by
the laws of matrix algebra, we can construct compact representations for the
derivatives and the integrals of logical functions. Inside this
semantic-algebraic calculus, we obtain expressions for the derivatives of some
of the basic logical operations and show the general way to obtain the
derivatives of any well-formed formula of propositional calculus. We show that
some of the basic tautologies (Excluded middle, Modus ponens, Hypothetical
syllogism) are members of a kind of hierarchical system linked by the
differentiation algorithm. In addition using the logical derivatives we show
that relatively complex formulas can collapse in simple expressions that reveal
clearly their hidden logical meaning. The search for the antiderivatives
produces naturally an integral calculus. Within this logical formalism an
indefinite integral can always be found for any logical expression. Moreover,
particular integrals can be constructed based on detachment properties that
lead to logical expressions of growing complexity. We show that these
particular integrals have some similarities with the 'generalizing deduction'
procedures investigated by Lukasiewicz.


title:
Probing nuclear effects using single-transverse kinematic imbalance with
  MINERvA

abstract:
  Kinematic imbalance of the final-state particles in the plane transverse to
the neutrino direction provides a sensitive probe of nuclear effects. In this
contribution, we report the MINERvA measurement of the single-transverse
kinematic imbalance in neutrino charged-current quasielastic-like events on CH
targets. To improve the momentum measurements of the final-state particles, we
develop a method to select elastically scattering contained (ESC) protons and a
general procedure to correct the transverse momentum scales.


title: Four-quark structure of Zc(3900), Z(4430) and Xb(5568) states

abstract:
  We examine the four-quark structure of the recently discovered charged
$Z_c(3900)$, $Z(4430)$, and $X_b(5568)$ states. We calculate the widths of the
strong decays $Z_c^+ \to J/\psi \pi^+$ ($\eta_c\rho^+$, $\bar D^0D^{\ast\,+}$,
$\bar D^{\ast\,0}D^+$), $Z(4430)^+ \to J/\psi \pi^+$ ($\psi(2s) \pi^+$), and
$X^+_b\to B_s\pi^+$ within a covariant quark model previously developed by us.
We find that the tetraquark-type current widely used in the literature for the
$Z_c(3900)$ leads to a significant suppression of the $\bar D D^\ast$ and $\bar
D^\ast D$ modes. Contrary to this a molecular-type current provides an
enhancement by a factor of 6-7 for the $\bar D D^\ast$ modes compared with the
$Z_c^+\to J/\psi\pi^+$, $\eta_c\rho^+$ modes in agreement with recent
experimental data from the BESIII Collaboration. In case of the $Z(4430)$ state
we test a sensitivity of the ratio $R_Z$ of the $Z(4430)^+ \to \psi(2s) \pi^+$
and $Z(4430)^+ \to J/\psi \pi^+$ decay rates to a choice of the size parameter
$\Lambda_{Z(4430)}$ of the $Z(4430)$. Using upper constraint for the sum of
these two modes deduced from the LHCb Collaboration data we find that $R_Z$
varies from 4.64 to 4.08 when $\Lambda_{Z(4430)}$ changes from 2.2 to 3.2 GeV.
Also we make the prediction for the $Z(4430)^+ \to D^{\ast\,+} \bar
D^{\ast\,0}$ decay rate.


title: Distributed chaos and Rayleigh-Benard turbulence at very high Ra

abstract:
  It is shown, by the means of distributed chaos approach and using the
experimental data, that at very large Rayleigh number $Ra > 10^{14}$ and
Prandtl number $Pr \sim 1$ the Rayleigh-B\'{e}nard turbulence can undergo a
transition related to spontaneous breaking of the fundamental Lagrangian
relabeling symmetry. Due to the Noether's theorem helicity plays central role
in this process. After the transition the temperature spectrum has a stretched
exponential form $E (k) \propto \exp(-k/k_{\beta})^{\beta}$ with $\beta =2/5$
both at the cell midplain and at the near-wall (low boundary) regions. There is
a similarity between this phenomenon and the effects of polymer additives.


title:
Entropic Lattice Boltzmann Method for Moving and Deforming Geometries in
  Three Dimensions

abstract:
  Entropic lattice Boltzmann methods have been developed to alleviate intrinsic
stability issues of lattice Boltzmann models for under-resolved simulations.
Its reliability in combination with moving objects was established for various
laminar benchmark flows in two dimensions in our previous work Dorschner et al.
[11] as well as for three dimensional one-way coupled simulations of
engine-type geometries in Dorschner et al. [12] for flat moving walls. The
present contribution aims to fully exploit the advantages of entropic lattice
Boltzmann models in terms of stability and accuracy and extends the methodology
to three-dimensional cases including two-way coupling between fluid and
structure, turbulence and deformable meshes. To cover this wide range of
applications, the classical benchmark of a sedimenting sphere is chosen first
to validate the general two-way coupling algorithm. Increasing the complexity,
we subsequently consider the simulation of a plunging SD7003 airfoil at a
Reynolds number of Re = 40000 and finally, to access the model's performance
for deforming meshes, we conduct a two-way coupled simulation of a
self-propelled anguilliform swimmer. These simulations confirm the viability of
the new fluid-structure interaction lattice Boltzmann algorithm to simulate
flows of engineering relevance.


title: The Generalized Metastable Switch Memristor Model

abstract:
  Memristor device modeling is currently a heavily researched topic and is
becoming ever more important as memristor devices make their way into CMOS
circuit designs, necessitating accurate and efficient memristor circuit
simulations. In this paper, the Generalized Metastable Switch (MSS) memristor
model is presented. The Generalized MSS model consists of a voltage-dependent
stochastic component and a voltage-dependent exponential diode current
component and is designed to be easy to implement, computationally efficient,
and amenable to modeling a wide range of different memristor devices.


title:
Quasistatic contact problem with unilateral constraint for
  elastic-viscoplastic materials

abstract:
  This paper consists of two parts. In the first part we prove the unique
solvability for the abstract variational-hemivariational inequality with
history-dependent operator. The proof is based on the existing result for the
static variational-hemivariational inequality and a fixed point argument. In
the second part, we consider a mathematical model which describes quasistatic
frictional contact between a deformable body and a rigid foundation. In the
model the material behaviour is modelled by an elastic-viscoplastic
constitutive law. The contact is described with a normal damped response,
unilateral constraint and memory term. In the analysis of this model we use the
abstract result from the first part of the paper.


title:
A Pathophysiological Model-Driven Communication for Dynamic Distributed
  Medical Best Practice Guidance Systems

abstract:
  There is a great divide between rural and urban areas, particularly in
medical emergency care. Although medical best practice guidelines exist in
hospital handbooks, they are often lengthy and difficult to apply clinically.
The challenges are exaggerated for doctors in rural areas and emergency medical
technicians (EMT) during patient transport.
  In this paper, we propose the concept of distributed executable medical best
practice guidance systems to assist adherence to best practice from the time
that a patient first presents at a rural hospital, through diagnosis and
ambulance transfer to arrival and treatment at a regional tertiary hospital
center. We codify complex medical knowledge in the form of simplified
distributed executable disease automata, from the thin automata at rural
hospitals to the rich automata in the regional center hospitals. However, a
main challenge is how to efficiently and safely synchronize distributed best
practice models as the communication among medical facilities, devices, and
professionals generates a large number of messages. This complex problem of
patient diagnosis and transport from rural to center facility is also fraught
with many uncertainties and changes resulting in a high degree of dynamism. To
address this situation, we propose a pathophysiological model-driven message
exchange communication architecture that ensures the real-time and dynamic
requirements of synchronization among distributed emergency best-practice
models are met in a reliable and safe manner. Taking the signs, symptoms, and
progress of stroke patients transported across a geographically distributed
healthcare network as the motivating use case, we implement our communication
system and apply it to our developed best practice automata using laboratory
simulations. Our proof-of-concept experiments shows there is potential for the
use of our system in a wide variety of domains.


title: Ramsey Partial Orders from Acyclic Graphs

abstract:
  We prove that finite partial orders with a linear extension form a Ramsey
class. Our proof is based on the fact that class of acyclic graphs has the
Ramsey property and uses the partite construction.


title: Higher-spin charges in Hamiltonian form. I. Bose fields

abstract:
  We study asymptotic charges for symmetric massless higher-spin fields on Anti
de Sitter backgrounds of arbitrary dimension within the canonical formalism. We
first analyse in detail the spin-3 example: we cast Fronsdal's action in
Hamiltonian form, we derive the charges and we propose boundary conditions on
the canonical variables that secure their finiteness. We then extend the
computation of charges and the characterisation of boundary conditions to
arbitrary spin.


title:
Variational Gaussian Process Auto-Encoder for Ordinal Prediction of
  Facial Action Units

abstract:
  We address the task of simultaneous feature fusion and modeling of discrete
ordinal outputs. We propose a novel Gaussian process(GP) auto-encoder modeling
approach. In particular, we introduce GP encoders to project multiple observed
features onto a latent space, while GP decoders are responsible for
reconstructing the original features. Inference is performed in a novel
variational framework, where the recovered latent representations are further
constrained by the ordinal output labels. In this way, we seamlessly integrate
the ordinal structure in the learned manifold, while attaining robust fusion of
the input features. We demonstrate the representation abilities of our model on
benchmark datasets from machine learning and affect analysis. We further
evaluate the model on the tasks of feature fusion and joint ordinal prediction
of facial action units. Our experiments demonstrate the benefits of the
proposed approach compared to the state of the art.


title:
Kodaikanal Digitized White-light Data Archive (1921-2011): Analysis of
  various solar cycle features

abstract:
  Long-term sunspot observations are key to understand and predict the solar
activities and its effects on the space weather.Consistent observations which
are crucial for long-term variations studies,are generally not available due to
upgradation/modifications of observatories over the course of time. We present
the data for a period of 90 years acquired from persistent observation at the
Kodaikanal observatory in India. We use an advanced semi-automated algorithm to
detect the sunspots form each calibrated white-light image. Area, longitude and
latitude of each of the detected sunspots are derived. Implementation of a
semi-automated method is very necessary in such studies as it minimizes the
human bias in the detection procedure. Daily, monthly and yearly sunspot area
variations obtained from the Kodaikanal, compared well with the Greenwich
sunspot area data. We find an exponentially decaying distribution for the
individual sunspot area for each of the solar cycles. Analyzing the histograms
of the latitudinal distribution of the detected sunspots, we find Gaussian
distributions, in both the hemispheres, with the centers at $\sim$15$^{\circ}$
latitude. The height of the Gaussian distributions are different for the two
hemispheres for a particular cycle. Using our data, we show clear presence of
Waldmeier effect which correlates the rise time with the cycle amplitude. Using
the wavelet analysis, we explored different periodicities of different time
scales present in the sunspot area times series.


title: A note on Products of Nilpotent Matrices

abstract:
  Let $\mathscr{F}$ be a field. A matrix $A$ of order $n \times n$ over
$\mathscr{F}$ is a product of two nilpotent matrices if and only if it is
singular, except if $A$ is a nonzero nilpotent matrix of order $2 \times 2$.
This result was proved independently by Sourour and Laffey. While these results
remain true and the general strategies and principles of the proofs correct,
there are certain problematic details in the original proofs which are resolved
in this article. A detailed and rigorous proof of the result based on Laffey's
original proof is provided, and a problematic detail in the Proposition which
is the main device underpinning the proof by Sourour is resolved.


title: Medical image denoising using convolutional denoising autoencoders

abstract:
  Image denoising is an important pre-processing step in medical image
analysis. Different algorithms have been proposed in past three decades with
varying denoising performances. More recently, having outperformed all
conventional methods, deep learning based models have shown a great promise.
These methods are however limited for requirement of large training sample size
and high computational costs. In this paper we show that using small sample
size, denoising autoencoders constructed using convolutional layers can be used
for efficient denoising of medical images. Heterogeneous images can be combined
to boost sample size for increased denoising performance. Simplest of networks
can reconstruct images with corruption levels so high that noise and signal are
not differentiable to human eye.


title:
Angular momentum, accretion and radial flows in chemodynamical models of
  spiral galaxies

abstract:
  Gas accretion and radial flows are key ingredients of the chemical evolution
of spiral galaxies. They are also tightly linked to each other (accretion
drives radial flows, due to angular momentum conservation) and should therefore
be modelled simultaneously. We summarise an algorithm that can be used to
consistently compute accretion profiles, radial flows and abundance gradients
under quite general conditions and we describe illustrative applications to the
Milky Way. We find that gas-phase abundance gradients strongly depend on the
angular momentum of the accreting material and, in the outer regions, they are
significantly affected by the choice of boundary conditions.


title:
History of cosmic evolution with modified Gauss-Bonnet-dilatonic coupled
  term

abstract:
  Gauss-Bonnet-dilatonic coupling in four dimension plays an important role to
explain late time cosmic evolution. However, this term is an outcome of low
energy string effective action and thus ought to be important in the early
universe too. Unfortunately, phase-space formulation of such a theory does not
exist in the literature due to branching. We therefore consider a modified
theory of gravity, which contains a nonminimally coupled scalar-tensor sector
in addition to higher order scalar curvature invariant term with
Gauss-Bonnet-dilatonic coupling. Such an action unifies early inflation with
late-time cosmic acceleration. Quantum version of the theory is also
well-behaved.


title: Attribute Extraction from Product Titles in eCommerce

abstract:
  This paper presents a named entity extraction system for detecting attributes
in product titles of eCommerce retailers like Walmart. The absence of syntactic
structure in such short pieces of text makes extracting attribute values a
challenging problem. We find that combining sequence labeling algorithms such
as Conditional Random Fields and Structured Perceptron with a curated
normalization scheme produces an effective system for the task of extracting
product attribute values from titles. To keep the discussion concrete, we will
illustrate the mechanics of the system from the point of view of a particular
attribute - brand. We also discuss the importance of an attribute extraction
system in the context of retail websites with large product catalogs, compare
our approach to other potential approaches to this problem and end the paper
with a discussion of the performance of our system for extracting attributes.


title:
Privacy Assessment of Software Architectures based on Static Taint
  Analysis

abstract:
  Privacy analysis is critical but also a time-consuming and tedious task. We
present a formalization which eases designing and auditing high-level privacy
properties of software architectures. It is incorporated into a larger policy
analysis and verification framework and enables the assessment of commonly
accepted data protection goals of privacy. The formalization is based on static
taint analysis and makes flow and processing of privacy-critical data explicit,
globally as well as on the level of individual data subjects. Formally, we show
equivalence to traditional label-based information flow security and prove
overall soundness of our tool with Isabelle/HOL. We demonstrate applicability
in two real-world case studies, thereby uncovering previously unknown
violations of privacy constraints in the analyzed software architectures.


title: Informal Physical Reasoning Processes

abstract:
  A fundamental question is whether Turing machines can model all reasoning
processes. We introduce an existence principle stating that the perception of
the physical existence of any Turing program can serve as a physical causation
for the application of any Turing-computable function to this Turing program.
The existence principle overcomes the limitation of the outputs of Turing
machines to lists, that is, recursively enumerable sets. The principle is
illustrated by productive partial functions for productive sets such as the set
of the Goedel numbers of the Turing-computable total functions. The existence
principle and productive functions imply the existence of physical systems
whose reasoning processes cannot be modeled by Turing machines. These systems
are called creative. Creative systems can prove the undecidable formula in
Goedel's theorem in another formal system which is constructed at a later point
in time. A hypothesis about creative systems, which is based on computer
experiments, is introduced.


title: Solvable primitive extensions

abstract:
  A finite separable extension $E$ of a field $F$ is called primitive if there
are no intermediate extensions. It is called solvable if the group
$\mathrm{Gal}(\hat E|F)$ of automorphisms of its galoisian closure $\hat E$
over $F$ is solvable, and a $p$-extension ($p$ prime) if the degree $[E:F]$ is
a power of $p$. We show that a solvable primitive $p$-extension $E$ of $F$ is
uniquely determined (up to $F$-isomorphism) by $\hat E$ and characterise the
extensions $D$ of $F$ such that $D=\hat E$ for some solvable primitive
$p$-extension $E$ of $F$.


title:
Shape Constrained Tensor Decompositions using Sparse Representations in
  Over-Complete Libraries

abstract:
  We consider $N$-way data arrays and low-rank tensor factorizations where the
time mode is coded as a sparse linear combination of temporal elements from an
over-complete library. Our method, Shape Constrained Tensor Decomposition
(SCTD) is based upon the CANDECOMP/PARAFAC (CP) decomposition which produces
$r$-rank approximations of data tensors via outer products of vectors in each
dimension of the data. By constraining the vector in the temporal dimension to
known analytic forms which are selected from a large set of candidate
functions, more readily interpretable decompositions are achieved and analytic
time dependencies discovered. The SCTD method circumvents traditional {\em
flattening} techniques where an $N$-way array is reshaped into a matrix in
order to perform a singular value decomposition. A clear advantage of the SCTD
algorithm is its ability to extract transient and intermittent phenomena which
is often difficult for SVD-based methods. We motivate the SCTD method using
several intuitively appealing results before applying it on a number of
high-dimensional, real-world data sets in order to illustrate the efficiency of
the algorithm in extracting interpretable spatio-temporal modes. With the rise
of data-driven discovery methods, the decomposition proposed provides a viable
technique for analyzing multitudes of data in a more comprehensible fashion.


title: A Stability Theorem for Maximal $K_{r+1}$-free Graphs

abstract:
  For $r \geq 2$, we show that every maximal $K_{r+1}$-free graph $G$ on $n$
vertices with $(1-\frac{1}{r})\frac{n^2}{2}-o(n^{\frac{r+1}{r}})$ edges
contains a complete $r$-partite subgraph on $(1 - o(1))n$ vertices. We also
show that this is best possible. This result answers a question of Tyomkyn and
Uzzell.


title: Isotope analysis in the transmission electron microscope

abstract:
  The {\AA}ngstr\"om-sized probe of the scanning transmission electron
microscope can visualize and collect spectra from single atoms. This can
unambiguously resolve the chemical structure of materials, but not their
isotopic composition. Here we differentiate between two isotopes of the same
element by quantifying how likely the energetic imaging electrons are to eject
atoms. First, we measure the displacement probability in graphene grown from
either $^{12}$C or $^{13}$C and describe the process using a quantum mechanical
model of lattice vibrations coupled with density functional theory simulations.
We then test our spatial resolution in a mixed sample by ejecting individual
atoms from nanoscale areas spanning an interface region that is far from
atomically sharp, mapping the isotope concentration with a precision better
than 20%. Although we use a scanning instrument, our method should be
applicable to any atomic resolution transmission electron microscope and to
other low-dimensional materials.


title:
The dependence of oxygen and nitrogen abundances on stellar mass from
  the CALIFA survey

abstract:
  We analysed the optical spectra of HII regions extracted from a sample of 350
galaxies of the CALIFA survey. We calculated total O/H abundances and, for the
first time, N/O ratios using the semi-empirical routine HII-CHI-mistry, which,
according to P\'erez-Montero (2014), is consistent with the direct method and
reduces the uncertainty in the O/H derivation using [NII] lines owing to the
dispersion in the O/H-N/O relation. Then we performed linear fittings to the
abundances as a function of the de-projected galactocentric distances. The
analysis of the radial distribution both for O/H and N/O in the non-interacting
galaxies reveals that both average slopes are negative, but a non-negligible
fraction of objects have a flat or even a positive gradient (at least 10\% for
O/H and 4\% for N/O). The slopes normalised to the effective radius appear to
have a slight dependence on the total stellar mass and the morphological type,
as late low-mass objects tend to have flatter slopes. No clear relation is
found, however, to explain the presence of inverted gradients in this sample,
and there is no dependence between the average slopes and the presence of a
bar. The relation between the resulting O/H and N/O linear fittings at the
effective radius is much tighter (correlation coefficient $\rho_s$ = 0.80) than
between O/H and N/O slopes ($\rho_s$ = 0.39) or for O/H and N/O in the
individual \hii\ regions ($\rho_s$ = 0.37). These O/H and N/O values at the
effective radius also correlate very tightly (less than 0.03 dex of dispersion)
with total luminosity and stellar mass. The relation with other integrated
properties, such as star formation rate, colour, or morphology, can be
understood only in light of the found relation with mass.


title: Quantum oscillations without magnetic field

abstract:
  When magnetic field $B$ is applied to a metal, nearly all observable
quantities exhibit oscillations periodic in $1/B$. Such quantum oscillations
reflect the fundamental reorganization of electron states into Landau levels as
a canonical response of the metal to the applied magnetic field. We predict
here that, remarkably, in the recently discovered Dirac and Weyl semimetals
quantum oscillations can occur in the complete absence of magnetic field. These
zero-field quantum oscillations are driven by elastic strain which, in the
space of the low-energy Dirac fermions, acts as a chiral gauge potential. We
propose an experimental setup in which the strain in a thin film (or nanowire)
can generate pseudomagnetic field $b$ as large as 15T and demonstrate the
resulting de Haas-van Alphen and Shubnikov-de Haas oscillations periodic in
$1/b$.


title: The Distortion-Rate Function of Sampled Wiener Processes

abstract:
  We consider the recovery of a continuous-time Wiener process from a quantized
or lossy compressed version of its uniform samples under limited bitrate and
sampling rate. We derive a closed form expression for the optimal tradeoff
among sampling rate, bitrate, and quadratic distortion in this setting. This
expression is given in terms of a reverse waterfilling formula over the
asymptotic spectral distribution of a sequence of finite-rank operators
associated with the optimal estimator of the Wiener process from its samples.
We show that the ratio between this expression and the standard distortion rate
function of the Wiener process, describing the optimal tradeoff between bitrate
and distortion without a sampling constraint, is only a function of the number
of bits per sample. For example using one bit per sample on average, the
expected distortion is approximately 1.2 times the standard distortion rate
function, indicating a performance loss of about 20% due to sampling. We next
consider the distortion when the continuous-time process is estimated from the
output of an encoder that is optimal with respect to the discrete-time samples.
We show that while the latter is strictly greater than the distortion under
optimal encoding, the ratio between the two does not exceed 1.027. We therefore
conclude that nearly optimal performance is attained even if the encoder is
unaware of the sampling rate and encodes the samples without taking into
account the continuous-time underlying process.


title:
Synchronization dynamics on the picosecond timescale in coupled
  Josephson junction neurons

abstract:
  Conventional digital computation is rapidly approaching physical limits for
speed and energy dissipation. Here we fabricate and test a simple neuromorphic
circuit that models neuronal somas, axons and synapses with superconducting
Josephson junctions. The circuit models two mutually coupled excitatory
neurons. In some regions of parameter space the neurons are desynchronized. In
others, the Josephson neurons synchronize in one of two states, in-phase or
anti-phase. An experimental alteration of the delay and strength of the
connecting synapses can toggle the system back and forth in a phase-flip
bifurcation. Firing synchronization states are calculated >70,000 times faster
than conventional digital approaches. With their speed and low energy
dissipation (10-17 Joules/spike), this set of proof-of- concept experiments
establishes Josephson junction neurons as a viable approach for improvements in
neuronal computation as well as applications in neuromorphic computing.

categories: q-bio.NC cond-mat.dis-nn cs.ET physics.bio-ph


title: Wave breaking in a shallow water model

abstract:
  We prove wave breaking --- bounded solutions with unbounded derivatives ---
in the nonlinear nonlocal equations which combine the dispersion relation of
water waves and the nonlinear shallow water equations, and which generalize the
Whitham equation to permit bidirectional wave propagation, provided that the
slope of the initial data is sufficiently negative.


title: Extent of error control in neural networks

abstract:
  The article sets and solves the task to control an error of the artificial
neural network with variable signal conductivity. This kind of neural networks
was especially developed to construct timetables. Behavior of such a neural
network can be described as dynamic system control problem. The authors gave as
the results of the solving the ANN feedback control problem.


title: A Penny Saved is a Penny Earned: Less Expensive Zero Coupon Bonds

abstract:
  In this paper we show how to hedge a zero coupon bond with a smaller amount
of initial capital than required by the classical risk neutral paradigm, whose
(trivial) hedging strategy does not suggest to invest in the risky assets. Long
dated zero coupon bonds we derive, invest first primarily in risky securities
and when approaching more and more the maturity date they increase also more
and more the fraction invested in fixed income. The conventional wisdom of
financial planners suggesting investor to invest in risky securities when they
are young and mostly in fixed income when they approach retirement, is here
made rigorous. The paper provides a strong warning for life insurers, pension
fund managers and long term investors to take the possibility of less expensive
products seriously to avoid the adverse consequences of the low interest rate
regimes that many developed economies face.


title: Exclusion bounds for extended anyons

abstract:
  We introduce a rigorous approach to the many-body spectral theory of extended
anyons, i.e. quantum particles confined to two dimensions that interact via
attached magnetic fluxes of finite extent. Our main results are many-body
magnetic Hardy inequalities and local exclusion principles for these particles,
leading to estimates for the ground-state energy of the anyon gas over the full
range of the parameters. This brings out further non-trivial aspects in the
dependence on the anyonic statistics parameter, and also gives improvements in
the ideal (non-extended) case.

categories: math-ph cond-mat.quant-gas math.MP math.SP


title: Modulational instability in a full-dispersion shallow water model

abstract:
  We propose a shallow water model which combines the dispersion relation of
water waves and the Boussinesq equations, and which extends the Whitham
equation to permit bidirectional propagation. We establish that its
sufficiently small, periodic wave train is spectrally unstable to long
wavelength perturbations, provided that the wave number is greater than a
critical value, like the Benjamin-Feir instability of a Stokes wave. We verify
that the asso- ciated linear operator possesses infinitely many collisions of
purely imaginary eigenvalues, but they do not contribute to instability away
from the origin in the spectral plane to the leading order in the amplitude
parameter. We discuss the effects of surface tension on the modulational
instability. The results agree with those from formal asymptotic expansions and
numerical computations for the physical problem.


title: Multi Query Optimization in GLADE

abstract:
  SQL-on-Hadoop systems, query optimization, data distribution over multiple
nodes and parallelization techniques are few of the areas under extreme
research these days. Big names like Amazon, Google, Microsoft and many more are
working on implementing systems for faster access of data from multiple nodes
reducing data mobility and increasing the parallelization. Queries are
retrieved and reviewed by the database systems in an efficient way in the least
amount of time by the introduction of various parallelization techniques by
running the same query in parallel over different nodes carrying the data.
Apart from multi-threading parallelization, there is another way of
parallelization that can be performed in order to further reduce retrieval time
hence improving the efficiency of the system; parallelization on user queries
on top of a DBMS/RDBMS. In this paper, we will study one such technique of how
multiple queries can run simultaneously on a system in order to increase the
efficiency by reducing the data retrieval from the storage. Maximum sharing of
workload has been performed by generating optimal and ubiquitous join plans for
a set of queries and then fed them to GLADE (Generalized Linear Aggregate
Distribution Engine), a scalable distributed system for large scale data
analytics. Our main work is centered on generating GLADE join plans for a
Multi-Query satisfying maximum number of queries in order to maximize data
sharing and minimize data retrieval for each individual query.


title:
Europium mixed-valence, long-range magnetic order, and dynamic magnetic
  response in EuCu$_{2}$(Si$_{x}$Ge$_{1-x}$)$_{2}$

abstract:
  In mixed-valence or heavy-fermion systems, the hybridization between local
$f$ orbitals and conduction band states can cause the suppression of long-range
magnetic order, which competes with strong spin fluctuations. Ce- and Yb-based
systems have been found to exhibit fascinating physical properties
(heavy-fermion superconductivity, non-Fermi-liquid states, etc.) when tuned to
the vicinity of magnetic quantum critical points by use of various external
control parameters (temperature, magnetic field, chemical composition).
Recently, similar effects (mixed-valence, Kondo fluctuations, heavy Fermi
liquid) have been reported to exist in some Eu-based compounds. Unlike Ce (Yb),
Eu has a multiple electron (hole) occupancy of its $4f$ shell, and the magnetic
Eu$^{2+}$ state ($4f^7$) has no orbital component in the usual $LS$ coupling
scheme, which can lead to a quite different and interesting physics. In the
EuCu$_{2}$(Si$_{x}$Ge$_{1-x}$)$_{2}$ series, where the valence can be tuned by
varying the Si/Ge ratio, it has been reported that a significant valence
fluctuation can exist even in the magnetic order regime. This paper presents a
detailed study of the latter material using different microscopic probes
(XANES, M\"ossbauer spectroscopy, elastic and inelastic neutron scattering), in
which the composition dependence of the magnetic order and dynamics across the
series is traced back to the change in the Eu valence state. In particular, the
results support the persistence of valence fluctuations into the
antiferromagnetic state over a sizable composition range below the critical Si
concentration $x_c \approx 0.65$. The sequence of magnetic ground states in the
series is shown to reflect the evolution of the magnetic spectral response.


title: Tuning Fuzzy Logic Programs with Symbolic Execution

abstract:
  Fuzzy logic programming is a growing declarative paradigm aiming to integrate
fuzzy logic into logic programming. One of the most difficult tasks when
specifying a fuzzy logic program is determining the right weights for each
rule, as well as the most appropriate fuzzy connectives and operators. In this
paper, we introduce a symbolic extension of fuzzy logic programs in which some
of these parameters can be left unknown, so that the user can easily see the
impact of their possible values. Furthermore, given a number of test cases, the
most appropriate values for these parameters can be automatically computed.


title:
A Shallow High-Order Parametric Approach to Data Visualization and
  Compression

abstract:
  Explicit high-order feature interactions efficiently capture essential
structural knowledge about the data of interest and have been used for
constructing generative models. We present a supervised discriminative
High-Order Parametric Embedding (HOPE) approach to data visualization and
compression. Compared to deep embedding models with complicated deep
architectures, HOPE generates more effective high-order feature mapping through
an embarrassingly simple shallow model. Furthermore, two approaches to
generating a small number of exemplars conveying high-order interactions to
represent large-scale data sets are proposed. These exemplars in combination
with the feature mapping learned by HOPE effectively capture essential data
variations. Moreover, through HOPE, these exemplars are employed to increase
the computational efficiency of kNN classification for fast information
retrieval by thousands of times. For classification in two-dimensional
embedding space on MNIST and USPS datasets, our shallow method HOPE with simple
Sigmoid transformations significantly outperforms state-of-the-art supervised
deep embedding models based on deep neural networks, and even achieved
historically low test error rate of 0.65% in two-dimensional space on MNIST,
which demonstrates the representational efficiency and power of supervised
shallow models with high-order feature interactions.


title:
Stellar Helium Burning in Other Universes: A solution to the triple
  alpha fine-tuning problem

abstract:
  Motivated by the possible existence of other universes, with different values
for the fundamental constants, this paper considers stellar models in universes
where $^8$Be is stable. Many previous authors have noted that stars in our
universe would have difficulty producing carbon and other heavy elements in the
absence of the well-known $^{12}$C resonance at 7.6 MeV. This resonance is
necessary because $^8$Be is unstable in our universe, so that carbon must be
produced via the triple alpha reaction to achieve the requisite abundance.
Although a moderate change in the energy of the resonance (200 -- 300 keV) will
indeed affect carbon production, an even smaller change in the binding energy
of beryllium ($\sim100$ keV) would allow $^8$Be to be stable. A stable isotope
with $A=8$ would obviate the need for the triple alpha process in general, and
the $^{12}$C resonance in particular, for carbon production. This paper
explores the possibility that $^8$Be can be stable in other universes. Simple
nuclear considerations indicate that bound states can be realized, with binding
energy $\sim0.1-1$ MeV, if the fundamental constants vary by a $\sim {\rm
few}-10$ percent. In such cases, $^8$Be can be synthesized through helium
burning, and $^{12}$C can be produced later through nuclear burning of
beryllium. This paper focuses on stellar models that burn helium into
beryllium; once the universe in question has a supply of stable beryllium,
carbon production can take place during subsequent evolution in the same star
or in later stellar generations. Using both a semi-analytic stellar structure
model as well as a state-of-the-art stellar evolution code, we find that viable
stellar configurations that produce beryllium exist over a wide range of
parameter space. Finally, we demonstrate that carbon can be produced during
later evolutionary stages.