title: Mean-field limits for large-scale random-access networks

abstract:
  We establish mean-field limits for large-scale random-access networks with
buffer dynamics and arbitrary interference graphs. While saturated-buffer
scenarios have been widely investigated and yield useful throughput estimates
for persistent sessions, they fail to capture the fluctuations in buffer
contents over time, and provide no insight in the delay performance of flows
with intermittent packet arrivals. Motivated by that issue, we explore in the
present paper random-access networks with buffer dynamics, where flows with
empty buffers refrain from competition for the medium. The occurrence of empty
buffers thus results in a complex dynamic interaction between activity states
and buffer contents, which severely complicates the performance analysis. Hence
we focus on a many-sources regime where the total number of nodes grows large,
which not only offers mathematical tractability but is also highly relevant
with the densification of wireless networks as the Internet of Things emerges.
We exploit time scale separation properties to prove that the properly scaled
buffer occupancy process converges to the solution of a deterministic
initial-value problem, and establish the existence and uniqueness of the
associated fixed point. This approach simplifies the performance analysis of
networks with huge numbers of nodes to a low-dimensional fixed-point
calculation. For the case of a complete interference graph, we demonstrate
asymptotic stability, provide a simple closed-form expression for the fixed
point, and prove interchange of the mean-field and steady-state limits. This
yields asymptotically exact approximations for key performance metrics, in
particular the stationary buffer content and packet delay distributions. The
methodological framework that we develop easily extends to various model
refinements as will be illustrated by several examples.


title: Thermoelectric transport in junctions of Majorana and Dirac channels

abstract:
  We investigate the thermoelectric current and heat conductance in a chiral
Josephson contact on a surface of a 3D topological insulator, covered with
superconducting and magnetic insulator films. The contact consists of two
junctions of Majorana and Dirac channels next to two superconductors. Geometric
asymmetry results in a supercurrent without a phase bias. The interference of
Dirac fermions causes oscillations of the electric and heat currents with an
unconventional period $2\Phi_0=h/e$ as functions of the Aharonov-Bohm flux. Due
to the gapless character of Majorana modes, there is no threshold for the
thermoelectric effect and the current-flux relationship is non-sinusoidal.
Depending on the magnetic flux, the direction of the electric current can be
both from the hot to cold lead and vice versa.


title: Coherent functional expansions in quantum field theory

abstract:
  A new formalism is introduced to treat problems in quantum field theory,
using coherent functional expansions rather than path integrals. The basic
results and identities of this approach are developed. In the case of a Bose
gas with point-contact interactions, this leads to a soluble functional
equation in the weak interaction limit, where the perturbing term is part of
the kinetic energy. This approach has the potential to prevent the Dyson
problem of divergence in perturbation theory.


title: Gossip training for deep learning

abstract:
  We address the issue of speeding up the training of convolutional networks.
Here we study a distributed method adapted to stochastic gradient descent
(SGD). The parallel optimization setup uses several threads, each applying
individual gradient descents on a local variable. We propose a new way to share
information between different threads inspired by gossip algorithms and showing
good consensus convergence properties. Our method called GoSGD has the
advantage to be fully asynchronous and decentralized. We compared our method to
the recent EASGD in \cite{elastic} on CIFAR-10 show encouraging results.


title:
Multiscale and multilevel technique for consistent segmentation of
  nonstationary time series

abstract:
  In this paper, we propose a fast, well-performing, and consistent method for
segmenting a piecewise-stationary, linear time series with an unknown number of
breakpoints. The time series model we use is the nonparametric Locally
Stationary Wavelet model, in which a complete description of the
piecewise-stationary second-order structure is provided by wavelet periodograms
computed at multiple scales and locations. The initial stage of our method is a
new binary segmentation procedure, with a theoretically justified and rapidly
computable test criterion that detects breakpoints in wavelet periodograms
separately at each scale. This is followed by within-scale and across-scales
post-processing steps, leading to consistent estimation of the number and
locations of breakpoints in the second-order structure of the original process.
An extensive simulation study demonstrates good performance of our method.


title:
Stapledon Decompositions and Inequalities for Coefficients of Chromatic
  Polynomials

abstract:
  We use a polynomial decomposition result by Stapledon to show that the
numerator polynomial of the Ehrhart series of an open polytope is the
difference of two symmetric polynomials with nonnegative integer coefficients.
We obtain a related decomposition for order polytopes and for the numerator
polynomial of the corresponding series for chromatic polynomials. The
nonnegativity of the coefficients in such decompositions provide inequalities
satisfied by the coefficients of chromatic polynomials for any simple graph.


title:
Hybrid annealing using a quantum simulator coupled to a classical
  computer

abstract:
  Finding the global minimum in a rugged potential landscape is a
computationally hard task, often equivalent to relevant optimization problems.
Simulated annealing is a computational technique which explores the
configuration space by mimicking thermal noise. By slow cooling, it freezes the
system in a low-energy configuration, but the algorithm often gets stuck in
local minima. In quantum annealing, the thermal noise is replaced by
controllable quantum fluctuations, and the technique can be implemented in
modern quantum simulators. However, quantum-adiabatic schemes become
prohibitively slow in the presence of quasidegeneracies. Here we propose a
strategy which combines ideas from simulated annealing and quantum annealing.
In such hybrid algorithm, the outcome of a quantum simulator is processed on a
classical device. While the quantum simulator explores the configuration space
by repeatedly applying quantum fluctuations and performing projective
measurements, the classical computer evaluates each configuration and enforces
a lowering of the energy. We have simulated this algorithm for small instances
of the random energy model, showing that it potentially outperforms both
simulated thermal annealing and adiabatic quantum annealing. It becomes most
efficient for problems involving many quasi-degenerate ground states.

categories: quant-ph cond-mat.dis-nn cond-mat.quant-gas physics.comp-ph


title: Prime spectra of ambiskew polynomial rings

abstract:
  We determine criteria for the prime spectrum of an ambiskew polynomial
algebra $R$ over an algebraically closed field $K$ to be akin to those of two
of the principal examples of such an algebra, namely the universal enveloping
algebra $U(sl_2)$ (in characteristic $0$) and its quantization $U_q(sl_2)$
(when $q$ is not a root of unity). More precisely, we aim to determine when the
prime spectrum of $R$ consists of $0$, the ideals $(z-\lambda)R$ for some
central element $z$ of $R$ and all $\lambda\in K$, and, for some positive
integer $d$ and each positive integer $m$, $d$ height two prime ideals with
Goldie rank $m$. New applications are to certain ambiskew polynomial rings over
coordinate rings of quantum tori which arise, as localizations of connected
quantized Weyl algebras.


title: Exciton-Polariton Flows in Cross-Dimensional Junctions

abstract:
  We study the nonequilibrium exciton-polariton condensation in 1D to 0D and 1D
to 2D junctions by means of non-resonant spectroscopy. The shape of our
potential landscape allows to probe the resonant transmission of a propagating
condensate between a quasi-1D waveguide and cylindrically symmetric states. We
observe a distinct mode selection by varying the position of the non-resonant
pump laser. Moreover, we study the the case of propagation from a localized
trapped condensate state into a waveguide channel. Here, the choice of the
position of the injection laser allows us to tune the output in the waveguide.
Our measurements are supported by an accurate Ginzburg-Landau modeling of the
system shining light on the underlying mechanisms.


title:
The sandpile revisited: Computer assisted determination of constitutive
  relations and the breaking of scaling

abstract:
  We revisit the problem of the stress distribution in a frictional sandpile
under gravity, equipped with a new numerical model of granular assemblies with
both normal and tangential (frictional) inter-granular forces. Numerical
simulations allow a determination of the spatial dependence of all the
components of the stress field as a function of systems size, the coefficient
of static friction and the frictional interaction with the bottom surface. Our
study clearly demonstrates that interaction with the bottom surface plays a
crucial role in the formation of a pressure dip under the apex of a granular
pile. Basic to the theory of sandpiles are assumptions about the form of
scaling solutions and constitutive relations for cohesive-less hard grains for
which no typical scale is available. We find that these constitutive relations
must be modified; moreover for smaller friction coefficients and smaller piles
these scaling assumptions break down in the bulk of the sandpile due to the
presence of length scales that must be carefully identified. After identifying
the crucial scale we provide a predictive theory to when scaling solutions are
expected to break down. At the bottom of the pile the scaling assumption always
breaks, due to the different interactions with the bottom surface. The
consequences for measurable quantities like the pressure distribution and shear
stress at the bottom of the pile are discussed. For example one can have a
transition from no dip in the base-pressure to a dip at the center of the pile
as a function of the system size.


title: Getting Closer to the Essence of Music: The Con Espressione Manifesto

abstract:
  This text offers a personal and very subjective view on the current situation
of Music Information Research (MIR). Motivated by the desire to build systems
with a somewhat deeper understanding of music than the ones we currently have,
I try to sketch a number of challenges for the next decade of MIR research,
grouped around six simple truths about music that are probably generally agreed
on, but often ignored in everyday research.


title: Homogeneous Bands

abstract:
  A countable band $B$ is called homogeneous if every isomorphism between
finitely generated subbands extends to an automorphism of $B$. In this paper we
give a complete classification of all the homogeneous bands. We prove that a
homogeneous band belongs to the variety of regular bands, and has a homogeneous
structure semilattice.


title:
Core Structure and Non-Abelian Reconnection of Defects in a Biaxial
  Nematic Spin-2 Bose-Einstein Condensate

abstract:
  We calculate the energetic structure of defect cores and propose controlled
methods to imprint a nontrivially entangled vortex pair that undergoes
non-Abelian vortex reconnection in a biaxial nematic spin-2 condensate. For a
singular vortex, we find three superfluid cores in addition to depletion of the
condensate density. These exhibit order parameter symmetries that are different
from the discrete symmetry of the biaxial nematic phase, forming an interface
between the defect and the bulk superfluid. We provide a detailed analysis of
phase mixing in the resulting vortex cores and find an instability dependent
upon the orientation of the order parameter. We further show that the spin-2
condensate is a promising system for observing spontaneous deformation of a
point defect into an "Alice ring" that has so far avoided experimental
detection.


title:
Finding the UV-Visible Path Forward: Proceedings of the Community
  Workshop to Plan the Future of UV/Visible Space Astrophysics

abstract:
  We present the science cases and technological discussions that came from the
workshop entitled "Finding the UV-Visible Path Forward" held at NASA GSFC June
25-26, 2015. The material presented outlines the compelling science that can be
enabled by a next generation space-based observatory dedicated for UV-visible
science, the technologies that are available to include in that observatory
design, and the range of possible alternative launch approaches that could also
enable some of the science. The recommendations to the Cosmic Origins Program
Analysis Group from the workshop attendees on possible future development
directions are outlined.

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


title:
A Computational Non-Commutative Geometry Program for Disordered
  Topological Insulators

abstract:
  It has been some time since non-commutative geometry was proposed by Jean
Bellissard as a theoretical framework for the investigation of homogeneous
condensed matter systems. Recently, Bellissard's approach has been
enthusiastically adopted in the relatively young field of topological
insulators, where it facilitated many rigorous results concerning the stability
of the topological invariants against disorder. In this work we present a
computational program based on the principles of non-commutative geometry and
showcase several applications to topological insulators. In the first part we
introduce the notion of a homogeneous material and define the class of
disordered crystals together with the classification table which conjectures
all topological phases from this class. We continue with a discussion of
electron dynamics in disordered crystals and we briefly review the theory of
topological invariants in the presence of strong disorder. We show how all
these can be captured in the language of non-commutative geometry using the
concept of non-commutative Brillouin torus, and present a list of known
formulas for various physical response functions. In the second part, we
introduce auxiliary algebras and develop a canonical finite-volume
approximation of the non-commutative Brillouin torus. Explicit numerical
algorithms for computing generic correlation functions are discussed. In the
third part we derive upper bounds on the numerical errors and demonstrate that
the canonical-finite volume approximation converges extremely fast to the
thermodynamic limit. Convergence tests and various applications concludes our
presentation.

categories: math-ph cond-mat.mtrl-sci math.MP math.NA math.OA


title:
Information Rates and post-FEC BER Prediction in Optical Fiber
  Communications

abstract:
  Information-theoretic metrics to analyze optical fiber communications systems
with binary and nonbinary soft-decision FEC are reviewed. The numerical
evaluation of these metrics in both simulations and experiments is also
discussed. Ready-to-use closed-form approximations are presented.


title:
Behavior of a trapezoid-based data acquisition system up to 100 kHz and
  beyond

abstract:
  In this work, we investigated the ability of a high-purity germanium detector
connected to a trapezoid-filter-based data acquisition system to reliably
record signals in spite of high sample activities. By activating multiple
Na$_{2}$CO$_{3}$ samples with different Na content, we were able to deduce
efficiency, resolution and dead time of the system used as a function of the
sample activity. Based on the results, we were able to find a setting which
allows measurements of event rates up to 35~kHz per readout channel with an
energy resolution of 0.3\% at the 2754 keV $^{24}$Na line.


title:
Magneto-optical switching in microcavities based on a TGG defect
  sandwiched between periodic and disordered one-dimensional photonic
  structures

abstract:
  The employment of magneto-optical materials to fabricate photonic crystals
gives the unique opportunity to achieve optical tuning by applying a magnetic
field. In this study we have simulated the transmission spectrum of a
microcavity in which the Bragg reflectors are made with silica (SiO2) and
yttria (Y2O3) and the defect layer is made with TGG (Tb3Ga5O12). We show that
the application of an external magnetic field results in a tuning of the defect
mode of the microcavity. In the simulations we have considered the wavelength
dependence of the refractive indexes and the Verdet constants of the materials.
A tuning of the defect mode of about 22 nm with a magnetic field of 5 T, at low
temperature (8 K), is demonstrated. Furthermore, we discuss the possibility to
tune a microcavity with disordered photonic structures as reflectors. In the
presence of the magnetic field such microcavity shows a shift of resonances in
a broad range of wavelengths. This study presents a method of contactless
optical tuning.


title: Inclusive breakup of three-fragment weakly bound nuclei

abstract:
  The inclusive breakup of three-fragment projectiles is discussed within a
four-body spectator model. Both the elastic breakup and the non-elastic breakup
are obtained in a unified framework. Originally developed in the 80's for
two-fragment projectiles such as the deuteron, in this paper the theory is
successfully generalized to three-fragment projectiles. The expression obtained
for the inclusive cross section allows the extraction of the incomplete fusion
cross section, and accordingly generalizes the surrogate method to cases such
as (t,p) and (t,n) reactions. It is found that two-fragment correlations inside
the projectile affect in a conspicuous way the elastic breakup cross section.
The inclusive non-elastic breakup cross section is calculated and is found to
contain the contribution of a three-body absorption term that is also strongly
influenced by the two-fragment correlations. This latter cross section contains
the so-called incomplete fusion where more than one compound nuclei are formed.
Our theory describes both stable weakly bound three-fragment projectiles and
unstable ones such as the Borromean nuclei.


title:
Perturbation-Based Regularization for Signal Estimation in Linear
  Discrete Ill-posed Problems

abstract:
  Estimating the values of unknown parameters from corrupted measured data
faces a lot of challenges in ill-posed problems. In such problems, many
fundamental estimation methods fail to provide a meaningful stabilized
solution. In this work, we propose a new regularization approach and a new
regularization parameter selection approach for linear least-squares discrete
ill-posed problems. The proposed approach is based on enhancing the
singular-value structure of the ill-posed model matrix to acquire a better
solution. Unlike many other regularization algorithms that seek to minimize the
estimated data error, the proposed approach is developed to minimize the
mean-squared error of the estimator which is the objective in many typical
estimation scenarios. The performance of the proposed approach is demonstrated
by applying it to a large set of real-world discrete ill-posed problems.
Simulation results demonstrate that the proposed approach outperforms a set of
benchmark regularization methods in most cases. In addition, the approach also
enjoys the lowest runtime and offers the highest level of robustness amongst
all the tested benchmark regularization methods.


title: Photonic Kondo model

abstract:
  Here we introduce and study a photonic analogue of the Kondo model. The model
is defined as a far detuned regime of photonic scattering off a three-level
emitter in a $\Lambda$-type configuration coupled to a one-dimensional
transmission line with linear dispersion. We characterize this system by
studying the dynamics of a local system (emitter) driven by a coherent field
pulse as well as the first- and second-order correlation functions of the
scattered light. Various polarization-dependent correlation effects including
entanglement between the emitter and transmitted photons are quantified by the
purity of the emitter's state. We also show that statistical properties of the
scattered light are very sensitive to the polarization of the incoming coherent
pulse.


title: Optimal adaptive estimation of linear functionals under sparsity

abstract:
  We consider the problem of estimation of a linear functional in the Gaussian
sequence model where the unknown vector theta in R^d belongs to a class of
s-sparse vectors with unknown s. We suggest an adaptive estimator achieving a
non-asymptotic rate of convergence that differs from the minimax rate at most
by a logarithmic factor. We also show that this optimal adaptive rate cannot be
improved when s is unknown. Furthermore, we address the issue of simultaneous
adaptation to s and to the variance sigma^2 of the noise. We suggest an
estimator that achieves the optimal adaptive rate when both s and sigma^2 are
unknown.


title:
Hybrid Optimal Control Problems for a Class of Semilinear Parabolic
  Equations

abstract:
  A class of optimal control problems of hybrid nature governed by semilinear
parabolic equations is considered. These problems involve the optimization of
switching times at which the dynamics, the integral cost, and the bounds on the
control may change. First- and second-order optimality conditions are derived.
The analysis is based on a reformulation involving a judiciously chosen
transformation of the time domains. For autonomous systems and time-independent
integral cost, we prove that the Hamiltonian is constant in time when evaluated
along the optimal controls and trajectories. A numerical example is provided.


title:
A high-resolution DNS study of compressible flow past an LPT blade in a
  cascade

abstract:
  Flow past a low pressure turbine blade in a cascade at $Re \approx 52000$ and
angle of incidence $\alpha = 45.5^{0}$ is solved using a code developed
in-house for solving 3D compressible Navier-Stokes equations. This code, named
ANUROOP, has been developed in the finite volume framework using kinetic energy
preserving second order central differencing scheme for calculating fluxes, and
is compatible with hybrid grids. ANUROOP was verified and validated against
several test cases with Mach numbers ranging from 0.1 (Taylor-Green vortex) to
1.5 (compressible turbulent channel flow). The code was found to be robust and
stable, and the kinetic energy decay obeys the compressible Navier-Stokes
equations.
  A hybrid grid, with a high resolution hexahedral orthogonal mesh in the
boundary layer and unstructured (also hexahedral) elements in the rest of the
domain, is used for the turbine blade simulation. Total grid size (160 million)
is approximately an order of magnitude higher than in previous simulations for
the same flow conditions and using similar numerical methods. The discrepancy
in the pressure distribution in earlier studies compared to experimental data
has been removed in this simulation. The trailing edge separation bubble has
been characterized and a detailed discussion on the effect of surface curvature
is presented.


title:
Appearance of stable minimal spheres along the Ricci flow in positive
  scalar curvature

abstract:
  We construct examples of spherical space forms $(S^3/\Gamma,g)$ with positive
scalar curvature and containing no stable embedded minimal surfaces, such that
the following happens along the Ricci flow starting at $(S^3/\Gamma,g)$: a
stable embedded minimal two-sphere appears and a non-trivial singularity
occurs. We also give in dimension $3$ a general contruction of Type I
neckpinching and clarify the relationship between stable spheres and
non-trivial Type I singularities of the Ricci flow. Some symmetry assumptions
prevent the appearance of stable spheres, and this has consequences on the
types of singularities which can occur for metrics with these symmetries.


title:
Nucleon-Nucleon Correlations, Short-lived Excitations, and the Quarks
  Within

abstract:
  This article reviews our current understanding of how the internal quark
structure of a nucleon bound in nuclei differs from that of a free nucleon. We
focus on the interpretation of measurements of the EMC effect for valence
quarks, a reduction in the Deep Inelastic Scattering (DIS) cross-section ratios
for nuclei relative to deuterium, and its possible connection to
nucleon-nucleon Short-Range Correlations (SRC) in nuclei. Our review and new
analysis (involving the amplitudes of non-nucleonic configurations in the
nucleus) of the available experimental and theoretical evidence shows that
there is a phenomenological relation between the EMC effect and the effects of
SRC that is not an accident. The influence of strongly correlated
neutron-proton pairs involving highly virtual nucleons is responsible for both
effects. These correlated pairs are temporary high-density fluctuations in the
nucleus in which the internal structure of the nucleons is briefly modified.
This conclusion needs to be solidified by the future experiments and improved
theoretical analyses that are discussed herein.


title: Diagonal-preserving graded isomorphisms of Steinberg algebras

abstract:
  We study Steinberg algebras constructed from ample Hausdorff groupoids over
commutative integral domains with identity. We reconstruct (graded) groupoids
from (graded) Steinberg algebras and use this to characterise when there is a
diagonal-preserving (graded) isomorphism between two (graded) Steinberg
algebras. We apply this characterisation to groupoids of directed graphs in
order to study diagonal-preserving (graded) isomorphisms of Leavitt path
algebras and graph $C^*$-algebras.


title:
Numerical determination of the CFT central charge in the site-diluted
  Ising model

abstract:
  We propose a new numerical method to determine the central charge of the
conformal field theory models corresponding to the 2D lattice models. In this
method, the free energy of the lattice model on the torus is calculated by the
Wang-Landau algorithm and then the central charge is obtained from a free
energy scaling with respect to the torus radii. The method is applied for
determination of the central charge in the site-diluted Ising model.


title:
The Effects of Communication Burstiness on Consensus Formation and
  Tipping Points in Social Dynamics

abstract:
  Current models for opinion dynamics typically utilize a Poisson process for
speaker selection, making the waiting time between events exponentially
distributed. Human interaction tends to be bursty, though, having higher
probabilities of either extremely short waiting times or long periods of
silence. To quantify the burstiness effects on the dynamics of social models,
we place in competition two groups exhibiting different speakers' waiting-time
distributions. These competitions are implemented in the binary Naming Game,
and show that the relevant aspect of the waiting-time distribution is the
density of the head rather than that of the tail. We show that even with
identical mean waiting times, a group with a higher density of short waiting
times is favored in competition over the other group. This effect remains in
the presence of nodes holding a single opinion that never changes, as the
fraction of such committed individuals necessary for achieving consensus
decreases dramatically when they have a higher head density than the holders of
the competing opinion. Finally, to quantify differences in burstiness, we
introduce the expected number of small-time activations and use it to
characterize the early-time regime of the system.


title: Magnonic quantum Hall effect and Wiedemann-Franz law

abstract:
  We present a quantum Hall effect of magnons in two-dimensional clean
insulating magnets at finite temperature. Through the Aharonov-Casher effect, a
magnon moving in an electric field acquires a geometric phase and forms Landau
levels in an electric field gradient of sawtooth form. At low temperatures, the
lowest energy band being almost flat carries a Chern number associated with a
Berry curvature. Appropriately defining the thermal conductance for bosons, we
find that the magnon Hall conductances get quantized and show a universal
thermomagnetic behavior, i.e., are independent of materials, and obey a
Wiedemann-Franz law for magnon transport. We consider magnons with quadratic
and linear (Dirac-like) dispersions. Finally, we show that our predictions are
within experimental reach for ferromagnets and skyrmion lattices with current
device and measurement techniques.

categories: cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.quant-gas cond-mat.stat-mech cond-mat.str-el


title:
The Atacama Cosmology Telescope: Two-Season ACTPol Lensing Power
  Spectrum

abstract:
  We report a measurement of the power spectrum of cosmic microwave background
(CMB) lensing from two seasons of Atacama Cosmology Telescope Polarimeter
(ACTPol) CMB data. The CMB lensing power spectrum is extracted from both
temperature and polarization data using quadratic estimators. We obtain results
that are consistent with the expectation from the best-fit Planck LCDM model
over a range of multipoles L=80-2100, with an amplitude of lensing A_lens =
1.06 +/- 0.15 (stat.) +/- 0.06 (sys.) relative to Planck. Our measurement of
the CMB lensing power spectrum gives sigma_8 Omega_m^0.25 = 0.643 +/- 0.054;
including baryon acoustic oscillation scale data, we constrain the amplitude of
density fluctuations to be sigma_8 = 0.831 +/- 0.053. We also update
constraints on the neutrino mass sum. We verify our lensing measurement with a
number of null tests and systematic checks, finding no evidence of significant
systematic errors. This measurement relies on a small fraction of the ACTPol
data already taken; more precise lensing results can therefore be expected from
the full ACTPol dataset.


title: On Scenario Aggregation to Approximate Robust Optimization Problems

abstract:
  As most robust combinatorial min-max and min-max regret problems with
discrete uncertainty sets are NP-hard, research into approximation algorithm
and approximability bounds has been a fruitful area of recent work. A simple
and well-known approximation algorithm is the midpoint method, where one takes
the average over all scenarios, and solves a problem of nominal type. Despite
its simplicity, this method still gives the best-known bound on a wide range of
problems, such as robust shortest path, or robust assignment problems.
  In this paper we present a simple extension of the midpoint method based on
scenario aggregation, which improves the current best $K$-approximation result
to an $(\varepsilon K)$-approximation for any desired $\varepsilon > 0$. Our
method can be applied to min-max as well as min-max regret problems.


title:
Fractional Order AGC for Distributed Energy Resources Using Robust
  Optimization

abstract:
  The applicability of fractional order (FO) automatic generation control (AGC)
for power system frequency oscillation damping is investigated in this paper,
employing distributed energy generation. The hybrid power system employs
various autonomous generation systems like wind turbine, solar photovoltaic,
diesel engine, fuel-cell and aqua electrolyzer along with other energy storage
devices like the battery and flywheel. The controller is placed in a remote
location while receiving and sending signals over an unreliable communication
network with stochastic delay. The controller parameters are tuned using robust
optimization techniques employing different variants of Particle Swarm
Optimization (PSO) and are compared with the corresponding optimal solutions.
An archival based strategy is used for reducing the number of function
evaluations for the robust optimization methods. The solutions obtained through
the robust optimization are able to handle higher variation in the controller
gains and orders without significant decrease in the system performance. This
is desirable from the FO controller implementation point of view, as the design
is able to accommodate variations in the system parameter which may result due
to the approximation of FO operators, using different realization methods and
order of accuracy. Also a comparison is made between the FO and the integer
order (IO) controllers to highlight the merits and demerits of each scheme.


title: A Framework for Assessing the Performance of Pulsar Search Pipelines

abstract:
  In this paper, we present a framework for assessing the effect of
non-stationary Gaussian noise and radio frequency interference (RFI) on the
signal to noise ratio, the number of false positives detected per true positive
and the sensitivity of standard pulsar search pipelines. The results highlight
the necessity to develop algorithms that are able to identify and remove
non-stationary variations from the data before RFI excision and searching is
performed in order to limit false positive detections. The results also show
that the spectrum whitening algorithms currently employed, severely affect the
efficiency of pulsar search pipelines by reducing their sensitivity to long
period pulsars.


title:
Estimates on Eisenstein distributions for reciprocals of p-adic
  L-functions: the case of irregular primes

abstract:
  We consider the p-adic distributions derived from Eisenstein series in
[GMPS], whose Mellin transforms are reciprocals of the Kubota-Leopoldt p-adic
L-function. These distributions were shown there to be measures when p is
regular. They fail to be measures when p is irregular; in this paper we give
quantitative estimates that describe their behavior more precisely.


title:
Charge pumping driven by the laser-induced dynamics of the exchange
  splitting

abstract:
  We show that electric currents are induced in inversion asymmetric
ferromagnets if the exchange splitting varies in time after excitation by laser
pulses. We interpret this phenomenon as the magnetic variant of the inverse
Edelstein effect. Based on \textit{ab initio} calculations we determine the
size of this effect in Co/Pt(111) and Mn/W(001) magnetic bilayer systems and
investigate its dependence on the magnetization direction. The comparison of
our theoretical results to experiments measuring the THz signal emitted after
laser excitation suggests that ultrafast demagnetization in 3$d$ transition
metal ferromagnets is dominated by transverse spin fluctuations rather than by
a reduction of the exchange splitting.


title:
On a functional equation related to a pair of hedgehogs with congruent
  projections

abstract:
  Hedgehogs are geometrical objects that describe the Minkowski differences of
arbitrary convex bodies in the Euclidean space $\mathbb{E}^n$. We prove that
two hedgehogs in $\mathbb{E}^n, n \geq 3$, coincide up to a translation and a
reflection in the origin, provided that their projections onto any
two-dimensional plane are directly congruent and have no direct rigid motion
symmetries. Our result is a consequence of a more general analytic statement
about the solutions of a functional equation in which the support functions of
hedgehogs are replaced with two arbitrary twice continuously differentiable
functions on the unit sphere.


title: Multipartite-entanglement detection with projective measurements

abstract:
  For a projective measurement, the Born rule provides the probability for an
outcome in terms of the inner product between a projector and a quantum state.
If the projector represents a pure entangled state and the state for a
composite system is separable, then we cannot get probability 1 for the
outcome. This insight delivers a single condition for entanglement detection.
By applying local unitary transformations from the Clifford group, we turn one
condition into many. Furthermore, we present two equivalent schemes---one
employs global and other requires local projective measurements---to test these
conditions in an experiment. Here, a global measurement is characterized by an
orthonormal basis that holds local-unitary-equivalent entangled kets. Whereas a
local-measurement setting is specified by mutually unbiased bases assigned to
the subsystems. We also supply a straightforward (computer) algorithm to
generate all the conditions and then to check whether a state is shown
entangled or not by these conditions. Finally, we demonstrate every element of
our schemes by considering several well-known examples of entangled kets and
states.


title: A candidate planetary-mass object with a photoevaporating disk in Orion

abstract:
  In this work, we report the discovery of a candidate planetary-mass object
with a photoevaporating protoplanetary disk, Proplyd 133-353, which is near the
massive star $\theta^{1}$ Ori C at the center of the Orion Nebula Cluster
(ONC). The object was known to have extended emission pointing away from
$\theta^{1}$ Ori C, indicating ongoing external photoevaporation. Our
near-infrared spectroscopic data suggests that the central source of Proplyd
133-353 is substellar ($\sim$M9.5), might have a mass probably less than 13
Jupiter mass and an age younger than 0.5 Myr. Proplyd 133-353 shows a similar
ratio of X-ray luminosity to stellar luminosity to other young stars in the ONC
with a similar stellar luminosity, and has a similar proper motion to the mean
one of confirmed ONC members. We propose that Proplyd 133-353 was formed in a
very low-mass dusty cloud near $\theta^{1}$ Ori C as a second-generation of
star formation, which can explain both its young age and the presence of its
disk.


title:
An improved bound on the packing dimension of Furstenberg sets in the
  plane

abstract:
  Let $0 \leq s \leq 1$. A set $K \subset \mathbb{R}^{2}$ is a Furstenberg
$s$-set, if for every unit vector $e \in S^{1}$, some line $L_{e}$ parallel to
$e$ satisfies $$\dim_{\mathrm{H}} [K \cap L_{e}] \geq s.$$ The Furstenberg set
problem, introduced by T. Wolff in 1999, asks for the best lower bound for the
dimension of Furstenberg $s$-sets. Wolff proved that $\dim_{\mathrm{H}} K \geq
\max\{s + 1/2,2s\}$ and conjectured that $\dim_{\mathrm{H}} K \geq (1 + 3s)/2$.
The only known improvement to Wolff's bound is due to Bourgain, who proved in
2003 that $\dim_{\mathrm{H}} K \geq 1 + \epsilon$ for Furstenberg $1/2$-sets
$K$, where $\epsilon > 0$ is an absolute constant. In the present paper, I
prove a similar $\epsilon$-improvement for all $1/2 < s < 1$, but only for
packing dimension: $\dim_{\mathrm{p}} K \geq 2s + \epsilon$ for all Furstenberg
$s$-sets $K \subset \mathbb{R}^{2}$, where $\epsilon > 0$ only depends on $s$.
  The proof rests on a new incidence theorem for finite collections of planar
points and tubes of width $\delta > 0$. As another corollary of this theorem, I
obtain a small improvement for Kaufman's estimate from 1968 on the dimension of
exceptional sets of orthogonal projections. Namely, I prove that if $K \subset
\mathbb{R}^{2}$ is a linearly measurable set with positive length, and $1/2 < s
< 1$, then $$\dim_{\mathrm{H}} \{e \in S^{1} : \dim_{\mathrm{p}} \pi_{e}(K)
\leq s\} \leq s - \epsilon$$ for some $\epsilon > 0$ depending only on $s$.
Here $\pi_{e}$ is the orthogonal projection onto the line spanned by $e$.


title:
A Reputation-Based Contract for Repeated Crowdsensing with Costly
  Verification

abstract:
  We study a setup in which a system operator hires a sensor to exert costly
effort to collect accurate measurements of a value of interest over time. At
each time, the sensor is asked to report his observation to the operator, and
is compensated based on the accuracy of this observation. Since both the effort
and observation are private information for the sensor, a naive payment scheme
which compensates the sensor based only on his self-reported values will lead
to both shirking and falsification of outcomes by the sensor. We consider the
problem of designing an appropriate compensation scheme to incentivize the
sensor to at once exert costly effort and truthfully reveal the resulting
observation.
  To this end, we formulate the problem as a repeated game and propose a
compensation scheme that employs stochastic verification by the operator
coupled with a system of assigning reputation to the sensor. In particular, our
proposed payment scheme compensates the sensor based on both the effort in the
current period as well as the history of past behavior. We show that by using
past behavior in determining present payments, the operator can both
incentivize higher effort as well as more frequent truthtelling by the sensor
and decrease the required verification frequency.


title:
Multi-Dimensional Phase Space Methods for Mass Measurements and Decay
  Topology Determination

abstract:
  Collider events with multi-stage cascade decays fill out the kinematically
allowed region in phase space with a density that is enhanced at the boundary.
The boundary encodes all available information about the spectrum and is well
populated even with moderate signal statistics due to this enhancement. In
previous work, the improvement in the precision of mass measurements for
cascade decays with three visible and one invisible particles was demonstrated
when the full boundary information is used instead of endpoints of
one-dimensional projections. We extend these results to cascade decays with
four visible and one invisible particles. We also comment on how the topology
of the cascade decay can be determined from the differential distribution of
events in these scenarios.


title: Generalization of the Wiener-Ikehara theorem

abstract:
  We study the Wiener-Ikehara theorem under the so-called log-linearly slowly
decreasing condition. Moreover, we clarify the connection between two different
hypotheses on the Laplace transform occurring in exact forms of the
Wiener-Ikehara theorem, that is, in "if and only if" versions of this theorem.


title:
Drift Removal in Plant Electrical Signals via IIR Filtering Using
  Wavelet Energy

abstract:
  Plant electrical signals often contains low frequency drifts with or without
the application of external stimuli. Quantification of the randomness in plant
signals in a stimulus-specific way is hindered because the knowledge of vital
frequency information in the actual biological response is not known yet. Here
we design an optimum Infinite Impulse Response (IIR) filter which removes the
low frequency drifts and preserves the frequency spectrum corresponding to the
random component of the unstimulated plant signals by bringing the bias due to
unknown artifacts and drifts to a minimum. We use energy criteria of wavelet
packet transform (WPT) for optimization based tuning of the IIR filter
parameters. Such an optimum filter enforces that the energy distribution of the
pre-stimulus parts in different experiments are almost overlapped but under
different stimuli the distributions of the energy get changed. The reported
research may popularize plant signal processing, as a separate field, besides
other conventional bioelectrical signal processing paradigms.


title:
Collective Decision Dynamics in Group Evacuation: Modeling Tradeoffs and
  Optimal Behavior

abstract:
  Quantifying uncertainties in collective human behavior and decision making is
crucial for ensuring public health and safety, enabling effective disaster
response, informing the design of transportation and communication networks,
and guiding the development of new technologies. However, modeling and
predicting such behavior is notoriously difficult, due to the influence of a
variety of complex factors such as the availability and uncertainty of
information, the interaction and influence of social groups and networks, the
degree of risk or time pressure involved in a situation, and differences in
individual personalities and preferences. Here, we develop a stochastic model
of human decision making to describe the empirical behavior of subjects in a
controlled experiment simulating a natural disaster scenario. We compare the
observed behavior to that of statistically optimal Bayesian decision makers,
quantifying the extent to which human decisions are optimal and identifying the
conditions in which sub-optimal decisions are made. Finally, we investigate how
human evacuation strategies change when decisions are made in groups under a
variety of different rules, and whether these group strategy adjustments are
optimal or beneficial.


title:
Study of lattice QCD at finite chemical potential using canonical
  ensemble approach

abstract:
  New approach to computation of canonical partition functions in $N_f=2$
lattice QCD is presented. We compare results obtained by new method with
results obtained by known method of hopping parameter expansion. We observe
agreement between two methods indicating validity of the new method. We use
results for the number density obtained in the confining and deconfining phases
at imaginary chemical potential to determine the phase transition line at real
chemical potential.


title: Computer Aided Detection of Oral Lesions on CT Images

abstract:
  Oral lesions are important findings on computed tomography (CT) images. In
this study, a fully automatic method to detect oral lesions in mandibular
region from dental CT images is proposed. Two methods were developed to
recognize two types of lesions namely (1) Close border (CB) lesions and (2)
Open border (OB) lesions, which cover most of the lesion types that can be
found on CT images. For the detection of CB lesions, fifteen features were
extracted from each initial lesion candidates and multi layer perceptron (MLP)
neural network was used to classify suspicious regions. Moreover, OB lesions
were detected using a rule based image processing method, where no feature
extraction or classification algorithm were used. The results were validated
using a CT dataset of 52 patients, where 22 patients had abnormalities and 30
patients were normal. Using non-training dataset, CB detection algorithm
yielded 71% sensitivity with 0.31 false positives per patient. Furthermore, OB
detection algorithm achieved 100% sensitivity with 0.13 false positives per
patient. Results suggest that, the proposed framework, which consists of two
methods, has the potential to be used in clinical context, and assist
radiologists for better diagnosis.


title:
Colloidal Surfaces with Boundaries, Apex Boojums and Nested Elastic
  Self-Assembly of Nematic Colloids

abstract:
  Self-assembly of colloidal particles is poised to become a powerful composite
material fabrication technique, but remains challenged by a limited control
over the ensuing structures. We develop a new breed of nematic colloids that
are physical analogs of a mathematical surface with boundary, interacting with
the molecular alignment field without inducing defects when flat. However, made
from a thin nanofoil, they can be shaped to prompt formation of
self-compensating defects that drive pre-programmed elastic interactions
mediated by the nematic host. To show this, we wrap the nanofoil on all
triangular side faces of a pyramid, except its square base. The ensuing
pyramidal cones induce point defects with fractional hedgehog charges of
opposite signs, spontaneously align with respect to the far-field director to
form elastic dipoles and nested assemblies with tunable spacing. Nanofoils
shaped into octahedrons interact as elastic quadrupoles. Our findings may drive
realization of low-symmetry colloidal phases.


title:
Optically and elastically assembled plasmonic nanoantennae for spatially
  resolved characterization of chemical composition in soft matter systems
  using surface enhanced spontaneous and stimulated Raman scattering

abstract:
  We present a method to locally probe spatially varying chemical composition
of soft matter systems by use of optically controlled and elastically
self-assembled plasmonic nanoantennae. Disc-shaped metal particles with sharp
irregular edges are optically trapped, manipulated, and assembled into small
clusters to provide a strong enhancement of the Raman scattering signal coming
from the sample regions around and in-between these particles. As the particles
are reassembled and spatially translated by computer-controlled laser tweezers,
we probe chemical composition as a function of spatial coordinates. This allows
us to reliably detect tiny quantities of organic molecules, such as capping
ligands present on various nanoparticles, as well as to probe chemical
composition of the interior of liquid crystal defect cores that can be filled
with, for example, polymer chains. The strong electromagnetic field enhancement
of optically-manipulated nanoparticles rough surfaces is demonstrated in
different forms of spectroscopy and microscopy, including enhanced spontaneous
Raman scattering, coherent anti-Stokes Raman scattering, and stimulated Raman
scattering imaging modes.


title:
Squeezing-enhanced measurement sensitivity in a cavity optomechanical
  system

abstract:
  We determine the theoretical limits to squeezing-enhanced measurement
sensitivity of mechanical motion in a cavity optomechanical system. The motion
of a mechanical resonator is transduced onto quadrature fluctuations of a
cavity optical field and a measurement is performed on the optical field
exiting the cavity. We compare measurement sensitivities obtained with coherent
probing and quantum-enhanced probing of the mechanical motion, i.e. the
coherent probe field carries vacuum states and quadrature squeezed vacuum
states at sideband frequencies, respectively. We find that quantum-enhanced
probing provides little to no improvement in motion sensing for resonators in
the unresolved sideband regime but may significantly increase measurement
sensitivities for resonators in the resolved sideband regime.


title: On an energy equality in the theory of evolution equations

abstract:
  We give an elementary proof of a basic "energy" equality in the theory of
evolution equations in the setting, which usually starts with introducing
$V\subset H=H^{*}\subset V^{*}$.


title:
Serving the Grid: an Experimental Study of Server Clusters as Real-Time
  Demand Response Resources

abstract:
  Demand response is a crucial technology to allow large-scale penetration of
intermittent renewable energy sources in the electric grid. This paper is based
on the thesis that datacenters represent especially attractive candidates for
providing flexible, real-time demand response services to the grid; they are
capable of finely-controllable power consumption, fast power ramp-rates, and
large dynamic range. This paper makes two main contributions: (a) it provides
detailed experimental evidence justifying this thesis, and (b) it presents a
comparative investigation of three candidate software interfaces for power
control within the servers. All of these results are based on a series of
experiments involving real-time power measurements on a lab-scale server
cluster. This cluster was specially instrumented for accurate and fast power
measurements on a time-scale of 100 ms or less. Our results provide preliminary
evidence for the feasibility of large scale demand response using datacenters,
and motivates future work on exploiting this capability.


title: Nonradial sign changing solutions to Lane Emden equation

abstract:
  In this paper we prove the existence of continua of nonradial solutions for
the Lane-Emden equation. In a first result we show that there are infinitely
many global continua detaching from the curve of radial solutions with any
prescribed number of nodal zones. Next, using the fixed point index in cone, we
produce nonradial solutions with a new type of symmetry. This result also
applies to solutions with fixed signed, showing that the set of solutions to
the Lane Emden problem has a very rich and complex structure.


title:
Improved noninterferometric test of collapse models using ultracold
  cantilevers

abstract:
  Spontaneous collapse models predict that a weak force noise acts on any
mechanical system, as a consequence of the collapse of the wave function.
Significant upper limits on the collapse rate have been recently inferred from
precision mechanical experiments, such as ultracold cantilevers and the space
mission LISA Pathfinder. Here, we report new results from an experiment based
on a high-Q cantilever cooled to millikelvin temperatures, which is potentially
able to improve the current bounds on the continuous spontaneous localization
(CSL) model by 1 order of magnitude. High accuracy measurements of the
cantilever thermal fluctuations reveal a nonthermal force noise of unknown
origin. This excess noise is compatible with the CSL heating predicted by
Adler. Several physical mechanisms able to explain the observed noise have been
ruled out.ler. Several physical mechanisms able to explain the observed noise
have been ruled out.


title: Phase diagram of diluted Ising ferromagnet LiHo$_x$Y$_{1-x}$F$_4$

abstract:
  We present a systematic study of the phase diagram of LiHo$_x$Y$_{1-x}$F$_4$
($0.25<x<1$) Ising ferromagnets obtained from neutron scattering measurements
and mean-field calculations. We show that while the thermal phase transition
decreases linearly with dilution, as predicted by mean-field theory, the
critical transverse field at the quantum critical point is suppressed much
faster. This behavior is related to competition between off-diagonal dipolar
coupling and quantum fluctuations that are tuned by doping and applied field,
respectively. In this paper, we quantify the deviation of the experimental
results from mean-field predictions, with the aim that this analysis can be
used in future theoretical efforts towards a quantitative description.


title:
Multi-objective LQR with Optimum Weight Selection to Design FOPID
  Controllers for Delayed Fractional Order Processes

abstract:
  An optimal trade-off design for fractional order (FO)-PID controller is
proposed in this paper with a Linear Quadratic Regulator (LQR) based technique
using two conflicting time domain control objectives. The deviation of the
state trajectories and control signal are automatically enforced by the LQR. A
class of delayed FO systems with single non-integer order element has been
controlled here which exhibit both sluggish and oscillatory open loop
responses. The FO time delay processes are controlled within a multi-objective
optimization (MOO) formulation of LQR based FOPID design. The time delays in
the FO models are handled by two analytical formulations of designing optimal
quadratic regulator for delayed systems. A comparison is made between the two
approaches of LQR design for the stabilization of time-delay systems in the
context of FOPID controller tuning. The MOO control design methodology yields
the Pareto optimal trade-off solutions between the tracking performance for
unit set-point change and total variation (TV) of the control signal. Numerical
simulations are provided to compare the merits of the two delay handling
techniques in the multi-objective LQR-FOPID design, while also showing the
capability of load disturbance suppression using these optimal controllers.
Tuning rules are then formed for the optimal LQR-FOPID controller knobs, using
the median of the non-dominated Pareto solution to handle delays FO processes.


title:
The Exit Distribution for Smart Kinetic Walk with Symmetric and
  Asymmetric Transition Probability

abstract:
  It has been proved that the distribution of the point where the Smart Kinetic
Walk (SKW) exits a domain converges in distribution to harmonic measure on the
hexagonal lattice. For other lattices, it is believed that this result still
holds, and there is good numerical evidence to support this conjecture. Here we
examine the effect of the symmetry and asymmetry of the transition probability
on each step of the SKW on the square lattice and test if the exit distribution
converges in distribution to harmonic measure as well. From our simulations,
the limiting exit distribution of the SKW with a non-uniform but symmetric
transition probability as the lattice spacing goes to zero is the harmonic
measure. This result does not hold for asymmetric transition probability. We
are also interested in the difference between the SKW with symmetric transition
probability exit distribution and harmonic measure. Our simulations provide
strong support for a explicit conjecture about this first order difference. The
explicit formula for the conjecture will be given below.


title: Decoupling of a Neutron Interferometer from Temperature Gradients

abstract:
  Neutron interferometry enables precision measurements that are typically
operated within elaborate, multi-layered facilities which provide substantial
shielding from environmental noise. These facilities are necessary to maintain
the coherence requirements in a perfect crystal neutron interferometer which is
extremely sensitive to local environmental conditions such as temperature
gradients across the interferometer, external vibrations, and acoustic waves.
The ease of operation and breadth of applications of perfect crystal neutron
interferometry would greatly benefit from a mode of operation which relaxes
these stringent isolation requirements. Here, the INDEX Collaboration and
National Institute of Standards and Technology demonstrates the functionality
of a neutron interferometer in vacuum and characterize the use of a compact
vacuum chamber enclosure as a means to isolate the interferometer from spatial
temperature gradients and time-dependent temperature fluctuations. The vacuum
chamber is found to have no depreciable effect on the performance of the
interferometer (contrast) while improving system stability, thereby showing
that it is feasible to replace large temperature isolation and control systems
with a compact vacuum enclosure for perfect crystal neutron interferometry.


title: Intrinsic Conformal Symmetries in Szekeres models

abstract:
  We show that Spatially Inhomogeneous (SI) and Irrotational dust models admit
a \emph{6-dimensional algebra } of \emph{Intrinsic Conformal Vector Fields}
(ICVFs) $\mathbf{X}_{\alpha }$ satisfying
$p_{a}^{c}p_{b}^{d}\mathcal{L}_{\mathbf{X}_{\alpha }}p_{cd}=2\phi
(\mathbf{X}_{\alpha })p_{ab}$ where $p_{ab}$ is the associated metric of the 2d
distribution $\mathcal{X}$ normal to the fluid velocity $u^{a}$ and the radial
unit spacelike vector field $x^{a}$. The Intrinsic Conformal (IC) algebra is
determined for each of the curvature value $\epsilon $ that characterizes the
structure of the screen space $\mathcal{X}$. In addition the conformal flatness
of the hypersurfaces $\mathbf{u}=\mathbf{0}$ indicates the existence of a
\emph{% 10-dimensional algebra} of ICVFs of the 3d metric $h_{ab}$. We
illustrate this expectation and propose a method to derive them by giving
explicitly the \emph{7 proper} ICVFs of the Lema\^{\i}tre-Tolman-Bondi (LTB)
model which represents the simplest subclass within the Szekeres family.


title: Swift observations of two outbursts from the magnetar 4U 0142+61

abstract:
  4U 0142+61 is one of a small class of persistently bright magnetars. Here we
report on a monitoring campaign of 4U 0142+61 from 2011 July 26 - 2016 June 12
using the Swift X-ray Telescope, continuing a 16 year timing campaign with the
Rossi X-ray Timing Explorer. We show that 4U 0142+61 had two radiatively loud
timing events, on 2011 July 29 and 2015 February 28, both with short soft
gamma-ray bursts, and a long-lived flux decay associated with each case. We
show that the 2015 timing event resulted in a net spin-down of the pulsar due
to over-recovery of a glitch. We compare this timing event to previous such
events in other high-magnetic-field pulsars, and discuss net spin-down glitches
now seen in several young, high-B pulsars.


title: Soft hairy horizons in three spacetime dimensions

abstract:
  We discuss some aspects of soft hairy black holes and a new kind of "soft
hairy cosmologies", including a detailed derivation of the metric formulation,
results on flat space, and novel observations concerning the entropy.
Remarkably, like in the case with negative cosmological constant, we find that
the asymptotic symmetries for locally flat spacetimes with a horizon are
governed by infinite copies of the Heisenberg algebra that generate soft hair
descendants. It is also shown that the generators of the three-dimensional
Bondi-Metzner-Sachs algebra arise from composite operators of the affine u(1)
currents through a twisted Sugawara-like construction. We then discuss entropy
macroscopically, thermodynamically and microscopically and discover that a
microscopic formula derived recently for boundary conditions associated to the
Korteweg-de Vries hierarchy fits perfectly our results for entropy and ground
state energy. We conclude with a comparison to related approaches.


title:
Multi-level Monte Carlo acceleration of computations on multi-layer
  materials with random defects

abstract:
  We propose a Multi-level Monte Carlo technique to accelerate Monte Carlo
sampling for approximation of properties of materials with random defects.
  The computational efficiency is investigated on test problems given by
tight-binding models of a single layer of graphene or of $MoS_2$ where the
integrated electron density of states per unit area is taken as a
representative quantity of interest.
  For the chosen test problems the multi-level Monte Carlo estimators
significantly reduce the computational time of standard Monte Carlo estimators
to obtain a given accuracy.


title: Minimal left-right symmetric intersecting D-brane model

abstract:
  We investigate left-right symmetric extensions of the standard model based on
open strings ending on D-branes, with gauge bosons due to strings attached to
stacks of D-branes and chiral matter due to strings stretching between
intersecting D-branes. The left-handed and right-handed fermions transform as
doublets under Sp(1)_L and Sp(1)_R, and so their masses must be generated by
the introduction of Higgs fields in a bi-fundamental (2,2) representation under
the two Sp(1) gauge groups. For such D-brane configurations the left-right
symmetry must be broken by Higgs fields in the doublet representation of
Sp(1)_R and therefore Majorana mass terms are suppressed by some higher physics
scale. The left-handed and right-handed neutrinos pair up to form Dirac
fermions which control the decay widths of the right-handed W' boson to yield
comparable branching fractions into dilepton and dijets channels. Using the
most recent searches at LHC13 Run II with 2016 data we constrain the (g_R,
m_{W'}) parameter space. Our analysis indicates that independent of the
coupling strength g_R, gauge bosons with masses m_{W'} \agt 3.5~{\rm TeV} are
not ruled out. As the LHC is just beginning to probe the TeV-scale, significant
room for W' discovery remains.


title:
A photon ratchet route to high-efficiency hybrid halide perovskite
  intermediate band solar cells

abstract:
  The spin-split indirect bandgap in hybrid-halide perovskites provides a
momentum-space realisation of a photon-ratchet intermediate band. Excited
electrons thermalise to recombination-protected Rashba pockets offset in
momentum space, building up the charge density to have sufficient flux to the
higher lying conduction band. This effect could be used to form an intrinsic
intermediate band solar cell with efficiencies beyond the Shockley-Queisser
limit if a selective low-electron affinity contact can be made to the higher
conduction state. This concept is supported by analysis of the many-body
electronic structure. Production of above-bandgap voltages under illumination
would affirm the physical mechanism proposed here.


title: Large-Scale Galaxy Bias

abstract:
  This review presents a comprehensive overview of galaxy bias, that is, the
statistical relation between the distribution of galaxies and matter. We focus
on large scales where cosmic density fields are quasi-linear. On these scales,
the clustering of galaxies can be described by a perturbative bias expansion,
and the complicated physics of galaxy formation is absorbed by a finite set of
coefficients of the expansion, called bias parameters. The review begins with a
detailed derivation of this very important result, which forms the basis of the
rigorous perturbative description of galaxy clustering, under the assumptions
of General Relativity and Gaussian, adiabatic initial conditions. Key
components of the bias expansion are all leading local gravitational
observables, which include the matter density but also tidal fields and their
time derivatives. We hence expand the definition of local bias to encompass all
these contributions. This derivation is followed by a presentation of the
peak-background split in its general form, which elucidates the physical
meaning of the bias parameters, and a detailed description of the connection
between bias parameters and galaxy statistics. We then review the excursion-set
formalism and peak theory which provide predictions for the values of the bias
parameters. In the remainder of the review, we consider the generalizations of
galaxy bias required in the presence of various types of cosmological physics
that go beyond pressureless matter with adiabatic, Gaussian initial conditions:
primordial non-Gaussianity, massive neutrinos, baryon-CDM isocurvature
perturbations, dark energy, and modified gravity. Finally, we discuss how the
description of galaxy bias in the galaxies' rest frame is related to clustering
statistics measured from the observed angular positions and redshifts in actual
galaxy catalogs.


title: A Contract Design Approach for Phantom Demand Response

abstract:
  We design an optimal contract between a demand response aggregator (DRA) and
power grid customers for incentive-based demand response. We consider a setting
in which the customers are asked to reduce their electricity consumption by the
DRA and they are compensated for this demand curtailment. However, given that
the DRA must supply every customer with as much power as she desires, a
strategic customer can temporarily increase her base load in order to report a
larger reduction as part of the demand response event. The DRA wishes to
incentivize the customers both to make costly effort to reduce load and to not
falsify the reported load reduction. We model this problem as a contract design
problem and present a solution. The proposed contract consists of two parts: a
part that depends on (the possibly inflated) load reduction as measured by the
DRA and another that provides a share of the profit that accrues to the DRA
through the demand response event to the customers. Since this profit accrues
due to the total load reduction because of the actions taken by all the
customers, the interaction among the customers also needs to be carefully
included in the contract design. The contract design and its properties are
presented and illustrated through examples.


title:
Optical properties of opaline photonic crystals covered by phase-change
  material Ge$_2$Sb$_2$Te$_5$

abstract:
  The physical origin of resonant Wood's anomalies in the reflection spectra of
three-dimensional (3D) opaline photonic crystals covered with
Ge$_2$Sb$_2$Te$_5$ (GST225) is discussed. For this purpose, the optical
reflection spectra are studied for different incident angles of light both
experimentally and theoretically. The performed eigenmode analysis reveals that
the Wood's anomalies originate from the quasiguided modes which appear in the
GST225 capping layer. This conclusion is supported by the simulated
electromagnetic near-field distributions of incident light at resonant
frequencies. The experimental reflection spectra are in a good agreement with
theoretical calculations performed by the Fourier modal method in the
scattering matrix form.


title:
Paired-move multiple-try stochastic search for Bayesian variable
  selection

abstract:
  Variable selection is a key issue when analyzing high-dimensional data. The
explosion of data with large sample sizes and dimensionality brings new
challenges to this problem in both inference accuracy and computational
complexity. To alleviate these problems, we propose a new scalable Markov chain
Monte Carlo (MCMC) sampling algorithm for "large $p$ small $n$" scenarios by
generalizing multiple-try Metropolis to discrete model spaces and further
incorporating neighborhood-based stochastic search. The proof of reversibility
of the proposed MCMC algorithm is provided. Extensive simulation studies are
performed to examine the efficiency of the new algorithm compared with existing
methods. A real data example is provided to illustrate the prediction
performances of the new algorithm.


title:
On the Existence of Synchrostates in Multichannel EEG Signals during
  Face-perception Tasks

abstract:
  Phase synchronisation in multichannel EEG is known as the manifestation of
functional brain connectivity. Traditional phase synchronisation studies are
mostly based on time average synchrony measures hence do not preserve the
temporal evolution of the phase difference. Here we propose a new method to
show the existence of a small set of unique phase synchronised patterns or
"states" in multi-channel EEG recordings, each "state" being stable of the
order of ms, from typical and pathological subjects during face perception
tasks. The proposed methodology bridges the concepts of EEG microstates and
phase synchronisation in time and frequency domain respectively. The analysis
is reported for four groups of children including typical, Autism Spectrum
Disorder (ASD), low and high anxiety subjects - a total of 44 subjects. In all
cases, we observe consistent existence of these states - termed as
synchrostates - within specific cognition related frequency bands (beta and
gamma bands), though the topographies of these synchrostates differ for
different subject groups with different pathological conditions. The
inter-synchrostate switching follows a well-defined sequence capturing the
underlying inter-electrode phase relation dynamics in stimulus- and
person-centric manner. Our study is motivated from the well-known EEG
microstate exhibiting stable potential maps over the scalp. However, here we
report a similar observation of quasi-stable phase synchronised states in
multichannel EEG. The existence of the synchrostates coupled with their unique
switching sequence characteristics could be considered as a potentially new
field over contemporary EEG phase synchronisation studies.


title: Colloidal-quantum-dot spasers and plasmonic amplifiers

abstract:
  Colloidal quantum dots are robust, efficient, and tunable emitters now used
in lighting, displays, and lasers. Consequently, when the spaser, a laser-like
source of surface plasmons, was first proposed, quantum dots were specified as
the ideal plasmonic gain medium. Subsequent spaser designs, however, have
required a single material to simultaneously provide gain and define the
plasmonic cavity, an approach ill-suited to quantum dots and other colloidal
nanomaterials. Here we develop a more open architecture that decouples the gain
medium from the cavity, leading to a versatile class of quantum-dot-based
spasers that allow controlled generation, extraction, and manipulation of
plasmons. We first create high-quality-factor, aberration-corrected, Ag
plasmonic cavities. We then incorporate quantum dots via electrohydrodynamic
printing18,19 or drop-casting. Photoexcitation under ambient conditions
generates monochromatic plasmons above threshold. This signal is extracted,
directed through an integrated amplifier, and focused at a nearby nanoscale
tip, generating intense electromagnetic fields. This spaser platform,
deployable at different wavelengths, size scales, and geometries, can enable
more complex on-chip plasmonic devices.

categories: physics.optics cond-mat.mes-hall cond-mat.mtrl-sci physics.chem-ph


title: Multifrequency interferometric imaging with intensity-only measurements

abstract:
  We propose an illumination strategy for interferometric imaging that allows
for robust depth recovery from intensity-only measurements. For an array with
colocated sources and receivers, we show that all the possible interferometric
data for multiple sources, receivers and frequencies can be recovered from
intensity-only measurements provided that we have sufficient source location
and frequency illumination diversity. There is no need for phase reconstruction
in this approach. Using interferometric imaging methods we show that in
homogeneous media there is no loss of resolution when imaging with
intensities-only. If in these imaging methods we reduce incoherence by
restricting the multifrequency interferometric data to nearby array elements
and nearby frequencies we obtain robust images in weakly inhomogeneous
background media with a somewhat reduced resolution.


title: Geometry of $\nu$-Tamari lattices in types $A$ and $B$

abstract:
  In this paper, we exploit the combinatorics and geometry of triangulations of
products of simplices to derive new results in the context of Catalan
combinatorics of $\nu$-Tamari lattices. In our framework, the main role of
"Catalan objects" is played by $(I,\overline{J})$-trees: bipartite trees
associated to a pair $(I,\overline{J})$ of finite index sets that stand in
simple bijection with lattice paths weakly above a lattice path
$\nu=\nu(I,\overline{J})$. Such trees label the maximal simplices of a
triangulation whose dual polyhedral complex gives a geometric realization of
the $\nu$-Tamari lattice introduced by Pr\'evile-Ratelle and Viennot. In
particular, we obtain geometric realizations of $m$-Tamari lattices as
polyhedral subdivisions of associahedra induced by an arrangement of tropical
hyperplanes, giving a positive answer to an open question of F.~Bergeron.
  The simplicial complex underlying our triangulation endows the $\nu$-Tamari
lattice with a full simplicial complex structure. It is a natural
generalization of the classical simplicial associahedron, alternative to the
rational associahedron of Armstrong, Rhoades and Williams, whose $h$-vector
entries are given by a suitable generalization of the Narayana numbers.
  Our methods are amenable to cyclic symmetry, which we use to present type $B$
analogues of our constructions. Notably, we define a partial order that
generalizes the type $B$ Tamari lattice, introduced independently by Thomas and
Reading, along with corresponding geometric realizations.


title:
Symbolic Representation for Analog Realization of A Family of Fractional
  Order Controller Structures via Continued Fraction Expansion

abstract:
  This paper uses the Continued Fraction Expansion (CFE) method for analog
realization of fractional order differ-integrator and few special classes of
fractional order (FO) controllers viz. Fractional Order
Proportional-Integral-Derivative (FOPID) controller, FO[PD] controller and FO
lead-lag compensator. Contemporary researchers have given several formulations
for rational approximation of fractional order elements. However, approximation
of the controllers studied in this paper, due to having fractional power of a
rational transfer function, is not available in analog domain; although its
digital realization already exists. This motivates us for applying CFE based
analog realization technique for complicated FO controller structures to get
equivalent rational transfer functions in terms of the controller tuning
parameters. The symbolic expressions for rationalized transfer function in
terms of the controller tuning parameters are especially important as ready
references, without the need of running CFE algorithm every time and also helps
in the synthesis of analog circuits for such FO controllers.


title: Yang--Mills Glueballs as Closed Bosonic Strings

abstract:
  We put forward the Axionic String Ansatz (ASA), which provides a unified
description for the worldsheet dynamics of confining strings in pure
Yang--Mills theory both in $D=3$ and $D=4$ space-time dimensions. The ASA is
motivated by the excitation spectrum of long confining strings, as measured on
a lattice, and by recently constructed integrable axionic non-critical string
models. According to the ASA, pure gluodynamics in 3D is described by a
non-critical bosonic string theory without any extra local worldsheet degrees
of freedom. We argue that this assumption fixes the set of quantum numbers
(spins, $P$- and $C$-parities) of almost all glueball states. We confront the
resulting predictions with the properties of approximately $1^2+2^2+3^2+5^2=39$
lightest glueball states measured on a lattice and find a good agreement. On
the other hand, the spectrum of low lying glueballs in 4D gluodynamics suggests
the presence of a massive pseudoscalar mode on the string worldsheet, in
agreement with the ASA and lattice data for long strings.


title: Radiatively generated hierarchy of lepton and quark masses

abstract:
  We propose a model for radiatively generating the hierarchy of the Standard
Model (SM) fermion masses: tree-level top quark mass; 1-loop bottom, charm, tau
and muon masses; 2-loop masses for the light up, down and strange quarks as
well as for the electron; and 4-loop masses for the light active neutrinos. Our
model is based on a softly-broken $S_{3}\times Z_{2}$ discrete symmetry. Its
scalar sector consists only of one SM Higgs doublet and three electrically
neutral SM-singlet scalars. We do not need to invoke either electrically
charged scalar fields, or an extra $SU_{2L}$ scalar doublet, or the spontaneous
breaking of the discrete group, which are typical for other radiative models in
the literature. The model features a viable scalar dark matter candidate.


title:
Notes on the phase space formulation of the propagator of Hamiltonians
  with spatially-dependent kinetic energy

abstract:
  These short notes present to the reader (students, in particular) a concise
approach to the derivation of the propagator of Hamiltonians with
position-dependent kinetic energy. The formalism is applied to the von Roos
Hamiltonian with arbitrary ordering ambiguity parameters, and a simple scheme
to convert the problem to a constant-mass motion is presented. The motion in
curved spaces is treated along the same lines, where a phase space formulation
is used to derive the propagator for arbitrary discretization choices.


title: Geometry of Compositionality

abstract:
  This paper proposes a simple test for compositionality (i.e., literal usage)
of a word or phrase in a context-specific way. The test is computationally
simple, relying on no external resources and only uses a set of trained word
vectors. Experiments show that the proposed method is competitive with state of
the art and displays high accuracy in context-specific compositionality
detection of a variety of natural language phenomena (idiomaticity, sarcasm,
metaphor) for different datasets in multiple languages. The key insight is to
connect compositionality to a curious geometric property of word embeddings,
which is of independent interest.


title:
Multi-Epoch Detections of Water Ice Absorption in Edge-on Disks around
  Herbig Ae Stars: PDS 144N and PDS 453

abstract:
  We report the multi-epoch detections of the water ice in 2.8-4.2 micron
spectra of two Herbig Ae stars, PDS 144N (A2 IVe) and PDS 453 (F2 Ve), which
have an edge-on circumstellar disk. The detected water ice absorption is found
to originate from their protoplanetary disks. The spectra show a relatively
shallow absorption of water ice around 3.1 micron for both objects. The optical
depths of the water ice absorption are ~0.1 and ~0.2 for PDS 144N and PDS 453,
respectively. Compared to the water ice previously detected in low-mass young
stellar objects with an edge-on disk with a similar inclination angle, these
optical depths are significantly lower. It suggests that stronger UV radiation
from the central stars effectively decreases the water ice abundance around the
Herbig Ae stars through photodesorption. The water ice absorption in PDS 453
shows a possible variation of the feature among the six observing epochs. This
variation could be due to a change of absorption materials passing through our
line-of-sight to the central star.


title:
New models for the evolution of central stars of planetary nebulae:
  Faster and Brighter

abstract:
  The post-asymptotic giant branch (AGB) phase is arguably one of the least
understood phases of the evolution of low- and intermediate- mass stars. The
recent post-AGB evolutionary sequences computed by Miller Bertolami (2016) are
at least three to ten times faster than those previously published by
Vassiliadis & Wood (1994) and Bloecker (1995) which have been used in a large
number of studies. This is true for the whole mass and metallicity range. The
new models are also $\sim$0.1-0.3 dex brighter than the previous models with
similar remnant masses. In this short article we comment on the main reasons
behind these differences, and discuss possible implications for other studies
of post-AGB stars or planetary nebulae.


title:
Fractional Order Load-Frequency Control of Interconnected Power Systems
  Using Chaotic Multi-objective Optimization

abstract:
  Fractional order proportional-integral-derivative (FOPID) controllers are
designed for load frequency control (LFC) of two interconnected power systems.
Conflicting time domain design objectives are considered in a multi objective
optimization (MOO) based design framework to design the gains and the
fractional differ-integral orders of the FOPID controllers in the two areas.
Here, we explore the effect of augmenting two different chaotic maps along with
the uniform random number generator (RNG) in the popular MOO algorithm - the
Non-dominated Sorting Genetic Algorithm-II (NSGA-II). Different measures of
quality for MOO e.g. hypervolume indicator, moment of inertia based diversity
metric, total Pareto spread, spacing metric are adopted to select the best set
of controller parameters from multiple runs of all the NSGA-II variants (i.e.
nominal and chaotic versions). The chaotic versions of the NSGA-II algorithm
are compared with the standard NSGA-II in terms of solution quality and
computational time. In addition, the Pareto optimal fronts showing the
trade-off between the two conflicting time domain design objectives are
compared to show the advantage of using the FOPID controller over that with
simple PID controller. The nature of fast/slow and high/low noise amplification
effects of the FOPID structure or the four quadrant operation in the two
inter-connected areas of the power system is also explored. A fuzzy logic based
method has been adopted next to select the best compromise solution from the
best Pareto fronts corresponding to each MOO comparison criteria. The time
domain system responses are shown for the fuzzy best compromise solutions under
nominal operating conditions. Comparative analysis on the merits and de-merits
of each controller structure is reported then. A robustness analysis is also
done for the PID and the FOPID controllers.


title:
InterpoNet, A brain inspired neural network for optical flow dense
  interpolation

abstract:
  Sparse-to-dense interpolation for optical flow is a fundamental phase in the
pipeline of most of the leading optical flow estimation algorithms. The current
state-of-the-art method for interpolation, EpicFlow, is a local average method
based on an edge aware geodesic distance. We propose a new data-driven
sparse-to-dense interpolation algorithm based on a fully convolutional network.
We draw inspiration from the filling-in process in the visual cortex and
introduce lateral dependencies between neurons and multi-layer supervision into
our learning process. We also show the importance of the image contour to the
learning process. Our method is robust and outperforms EpicFlow on competitive
optical flow benchmarks with several underlying matching algorithms. This leads
to state-of-the-art performance on the Sintel and KITTI 2012 benchmarks.


title: Best linear unbiased estimators in continuous time regression models

abstract:
  In this paper the problem of best linear unbiased estimation is investigated
for continuous-time regression models. We prove several general statements
concerning the explicit form of the best linear unbiased estimator (BLUE), in
particular when the error process is a smooth process with one or several
derivatives of the response process available for construction of the
estimators. We derive the explicit form of the BLUE for many specific models
including the cases of continuous autoregressive errors of order two and
integrated error processes (such as integrated Brownian motion). The results
are illustrated by several examples.


title:
A new primal-dual algorithm for minimizing the sum of three functions
  with a linear operator

abstract:
  In this paper, we propose a new primal-dual algorithm for minimizing $f(x) +
g(x) + h(Ax)$, where $f$, $g$, and $h$ are proper lower semi-continuous convex
functions, $f$ is differentiable with a Lipschitz continuous gradient, and $A$
is a bounded linear operator. The proposed algorithm has some famous
primal-dual algorithms for minimizing the sum of two functions as special
cases. E.g., it reduces to the Chambolle-Pock algorithm when $f = 0$ and the
proximal alternating predictor-corrector when $g = 0$. For the general convex
case, we prove the convergence of this new algorithm in terms of the distance
to a fixed point by showing that the iteration is a nonexpansive operator. In
addition, we prove the $O(1/k)$ ergodic convergence rate in the primal-dual
gap. With additional assumptions, we derive the linear convergence rate in
terms of the distance to the fixed point. Comparing to other primal-dual
algorithms for solving the same problem, this algorithm extends the range of
acceptable parameters to ensure its convergence and has a smaller per-iteration
cost. The numerical experiments show the efficiency of this algorithm.


title: Squarefree values of polynomial discriminants I

abstract:
  We determine the density of monic integer polynomials of given degree $n>1$
that have squarefree discriminant; in particular, we prove for the first time
that the lower density of such polynomials is positive. Similarly, we prove
that the density of monic integer polynomials $f(x)$, such that $f(x)$ is
irreducible and $\mathbb Z[x]/(f(x))$ is the ring of integers in its fraction
field, is positive, and is in fact given by $\zeta(2)^{-1}$.
  It also follows from our methods that there are $\gg X^{1/2+1/n}$ monogenic
number fields of degree $n$ having associated Galois group $S_n$ and absolute
discriminant less than $X$, and we conjecture that the exponent in this lower
bound is optimal.


title: Redshift of a photon emitted along the black hole horizon

abstract:
  In this work we derive some general features of the redshift measured by
radially moving observers in the black hole background. Let observer 1 cross
the black hole horizon emitting of a photon while observer 2 crossing the same
horizon later receives it. We show that if (i) the horizon is the outer one
(event horizon) and (ii) it is nonextremal, received frequency is redshifted.
This generalizes previous recent results in literature. For the inner horizon
(like in the Reissner-Nordstr\"{o}m metric) the frequency is blueshifted. If
the horizon is extremal, the frequency does not change. We derive explicit
formulas describing the frequency shift in generalized Kruskal- and
Lemaitre-like coordinates.


title: One loop amplitude for Heterotic string on $T^2$

abstract:
  We revisit the results of one loop string amplitude calculations for the
Heterotic string theory compactified on a torus with or without Wilson lines.
We give the complete elliptic genus and the harmonic part of the CP-even
amplitude for the gauge groups $SO(32)$, $E_8 \times E_8$, $SO(16)^2$ and
$SO(8)^4$.


title:
Fractional Order Fuzzy Control of Hybrid Power System with Renewable
  Generation Using Chaotic PSO

abstract:
  This paper investigates the operation of a hybrid power system through a
novel fuzzy control scheme. The hybrid power system employs various autonomous
generation systems like wind turbine, solar photovoltaic, diesel engine,
fuel-cell, aqua electrolyzer etc. Other energy storage devices like the
battery, flywheel and ultra-capacitor are also present in the network. A novel
fractional order (FO) fuzzy control scheme is employed and its parameters are
tuned with a particle swarm optimization (PSO) algorithm augmented with two
chaotic maps for achieving an improved performance. This FO fuzzy controller
shows better performance over the classical PID, and the integer order fuzzy
PID controller in both linear and nonlinear operating regimes. The FO fuzzy
controller also shows stronger robustness properties against system parameter
variation and rate constraint nonlinearity, than that with the other controller
structures. The robustness is a highly desirable property in such a scenario
since many components of the hybrid power system may be switched on/off or may
run at lower/higher power output, at different time instants.


title:
Phenomenology with fluctuating quantum geometries in loop quantum
  cosmology

abstract:
  The goal of this paper is to probe phenomenological implications of large
fluctuations of quantum geometry in the Planck era, using cosmology of the
early universe. For the background (Friedmann, Lema\^{i}tre, Robertson, Walker)
\emph{quantum} geometry, we allow `widely spread' states in which the
\emph{relative} dispersions are as large as $168\%$ in the Planck regime. By
introducing suitable methods to overcome the ensuing conceptual and
computational issues, we calculate the power spectrum $P_{\mathcal{R}}(k)$ and
the spectral index $n_s(k)$ of primordial curvature perturbations. These
results generalize the previous work in loop quantum cosmology which focused on
those states which were known to remain sharply peaked throughout the Planck
regime. Surprisingly, even though the fluctuations we now consider are large,
their presence does not add new features to the final $P_{\mathcal{R}}(k)$ and
$n_s(k)$: Within observational error bars, their effect is degenerate with a
different freedom in the theory, namely the number of \emph{pre-inflationary}
e-folds $N_{{\rm B}\,\star}$ between the bounce and the onset of inflation.
Therefore, with regard to observational consequences, one can simulate the
freedom in the choice of states with large fluctuations in the Planck era using
the simpler, sharply peaked states, simply by allowing for different values of
$N_{{\rm B}\,\star}$.


title: 3D Ultrasound image segmentation: A Survey

abstract:
  Three-dimensional Ultrasound image segmentation methods are surveyed in this
paper. The focus of this report is to investigate applications of these
techniques and a review of the original ideas and concepts. Although many
two-dimensional image segmentation in the literature have been considered as a
three-dimensional approach by mistake but we review them as a three-dimensional
technique. We select the studies that have addressed the problem of medical
three-dimensional Ultrasound image segmentation utilizing their proposed
techniques. The evaluation methods and comparison between them are presented
and tabulated in terms of evaluation techniques, interactivity, and robustness.


title:
Limiting the effects of earthquakes on gravitational-wave
  interferometers

abstract:
  Ground-based gravitational wave interferometers such as the Laser
Interferometer Gravitational-wave Observatory (LIGO) are susceptible to
high-magnitude teleseismic events, which can interrupt their operation in
science mode and significantly reduce the duty cycle. It can take several hours
for a detector to stabilize enough to return to its nominal state for
scientific observations. The down time can be reduced if advance warning of
impending shaking is received and the impact is suppressed in the isolation
system with the goal of maintaining stable operation even at the expense of
increased instrumental noise. Here we describe an early warning system for
modern gravitational-wave observatories. The system relies on near real-time
earthquake alerts provided by the U.S. Geological Survey (USGS) and the
National Oceanic and Atmospheric Administration (NOAA). Hypocenter and
magnitude information is generally available in 5 to 20 minutes of a
significant earthquake depending on its magnitude and location. The alerts are
used to estimate arrival times and ground velocities at the gravitational-wave
detectors. In general, 90\% of the predictions for ground-motion amplitude are
within a factor of 5 of measured values. The error in both arrival time and
ground-motion prediction introduced by using preliminary, rather than final,
hypocenter and magnitude information is minimal. By using a machine learning
algorithm, we develop a prediction model that calculates the probability that a
given earthquake will prevent a detector from taking data. Our initial results
indicate that by using detector control configuration changes, we could prevent
interruption of operation from 40-100 earthquake events in a 6-month
time-period.


title:
Monocular 3D Human Pose Estimation In The Wild Using Improved CNN
  Supervision

abstract:
  We propose a CNN-based approach for 3D human body pose estimation from single
RGB images that addresses the issue of limited generalizability of models
trained solely on the starkly limited publicly available 3D pose data. Using
only the existing 3D pose data and 2D pose data, we show state-of-the-art
performance on established benchmarks through transfer of learned features,
while also generalizing to in-the-wild scenes. We further introduce a new
training set for human body pose estimation from monocular images of real
humans that has the ground truth captured with a multi-camera marker-less
motion capture system. It complements existing corpora with greater diversity
in pose, human appearance, clothing, occlusion, and viewpoints, and enables an
increased scope of augmentation. We also contribute a new benchmark that covers
outdoor and indoor scenes, and demonstrate that our 3D pose dataset shows
better in-the-wild performance than existing annotated data, which is further
improved in conjunction with transfer learning from 2D pose data. All in all,
we argue that the use of transfer learning of representations in tandem with
algorithmic and data contributions is crucial for general 3D body pose
estimation.


title:
Towards a Global Controller Design for Guaranteed Synchronization of
  Switched Chaotic Systems

abstract:
  In this paper, synchronization of identical switched chaotic systems is
explored based on Lyapunov theory of guaranteed stability. Concepts from robust
control principles and switched linear systems are merged together to derive a
sufficient condition for synchronization of identical master-slave switched
nonlinear chaotic systems and are expressed in the form of bilinear matrix
inequalities (BMIs). The nonlinear controller design problem is then recast in
the form of linear matrix inequalities (LMIs) to facilitate numerical
computation by standard LMI solvers and is illustrated by appropriate examples.


title: The term a_4 in the heat kernel expansion of noncommutative tori

abstract:
  We consider the Laplacian associated with a general metric in the canonical
conformal structure of the noncommutative two torus, and calculate a local
expression for the term a_4 that appears in its corresponding small-time heat
kernel expansion. The final formula involves one variable functions and lengthy
two, three and four variable functions of the modular automorphism of the state
that encodes the conformal perturbation of the flat metric. We confirm the
validity of the calculated expressions by showing that they satisfy a family of
conceptually predicted functional relations. By studying these functional
relations abstractly, we derive a partial differential system which involves a
natural action of cyclic groups of order two, three and four and a flow in
parameter space. We discover symmetries of the calculated expressions with
respect to the action of the cyclic groups. In passing, we show that the main
ingredients of our calculations, which come from a rearrangement lemma and
relations between the derivatives up to order four of the conformal factor and
those of its logarithm, can be derived by finite differences from the
generating function of the Bernoulli numbers and its multiplicative inverse. We
then shed light on the significance of exponential polynomials and their smooth
fractions in understanding the general structure of the noncommutative
geometric invariants appearing in the heat kernel expansion. As an application
of our results we obtain the a_4 term for noncommutative four tori which split
as products of two tori. These four tori are not conformally flat and the a_4
term gives a first hint of the Riemann curvature and the higher dimensional
modular structure.


title: Co-adaptive learning over a countable space

abstract:
  Co-adaptation is a special form of on-line learning where an algorithm
$\mathcal{A}$ must assist an unknown algorithm $\mathcal{B}$ to perform some
task. This is a general framework and has applications in recommendation
systems, search, education, and much more. Today, the most common use of
co-adaptive algorithms is in brain-computer interfacing (BCI), where algorithms
help patients gain and maintain control over prosthetic devices. While previous
studies have shown strong empirical results Kowalski et al. (2013); Orsborn et
al. (2014) or have been studied in specific examples Merel et al. (2013, 2015),
there is no general analysis of the co-adaptive learning problem. Here we will
study the co-adaptive learning problem in the online, closed-loop setting. We
will prove that, with high probability, co-adaptive learning is guaranteed to
outperform learning with a fixed decoder as long as a particular condition is
met.


title:
Scalar and higher even spin glueball masses from an anomalous modified
  holographic model

abstract:
  In this work, within an anomalous modified holographic softwall model, we
calculate analytically the masses of the scalar glueball with its radial
excitations and higher even glueball spin states, with $P=C=+1$, from a single
mass equation. Using this approach we achieved an unified treatment for both
scalar and high even spin glueballs masses. Furthermore, we also obtain the
Regge trajectory associated with the pomeron compatible with other approaches.