title: Hardness of Permutation Pattern Matching

abstract:
  Permutation Pattern Matching (or PPM) is a decision problem whose input is a
pair of permutations $\pi$ and $\tau$, represented as sequences of integers,
and the task is to determine whether $\tau$ contains a subsequence
order-isomorphic to $\pi$. Bose, Buss and Lubiw proved that PPM is NP-complete
on general inputs.
  We show that PPM is NP-complete even when $\pi$ has no decreasing subsequence
of length 3 and $\tau$ has no decreasing subsequence of length 4. This provides
the first known example of PPM being hard when one or both of $\pi$ and
$\sigma$ are restricted to a proper hereditary class of permutations.
  This hardness result is tight in the sense that PPM is known to be polynomial
when both $\pi$ and $\tau$ avoid a decreasing subsequence of length 3, as well
as when $\pi$ avoids a decreasing subsequence of length 2. The result is also
tight in another sense: we will show that for any hereditary proper subclass C
of the class of permutations avoiding a decreasing sequence of length 3, there
is a polynomial algorithm solving PPM instances where $\pi$ is from C and
$\tau$ is arbitrary.
  We also obtain analogous hardness and tractability results for the class of
so-called skew-merged patterns.
  From these results, we deduce a complexity dichotomy for the PPM problem
restricted to $\pi$ belonging to $Av(\rho)$, where $Av(\rho)$ denotes the class
of permutations avoiding a permutation $\rho$. Specifically, we show that the
problem is polynomial when $\rho$ is in the set {1, 12, 21, 132, 213, 231,
312}, and it is NP-complete for any other $\rho$.


title: Early Methods for Detecting Adversarial Images

abstract:
  Many machine learning classifiers are vulnerable to adversarial
perturbations. An adversarial perturbation modifies an input to change a
classifier's prediction without causing the input to seem substantially
different to human perception. We deploy three methods to detect adversarial
images. Adversaries trying to bypass our detectors must make the adversarial
image less pathological or they will fail trying. Our best detection method
reveals that adversarial images place abnormal emphasis on the lower-ranked
principal components from PCA. Other detectors and a colorful saliency map are
in an appendix.


title: Line Percolation in Finite Projective Planes

abstract:
  We study combinatorial parameters of a recently introduced bootstrap
percolation problem in finite projective planes. We present sharp results on
the size of the minimum percolating sets and the maximal non-percolating sets.
Additional results on the minimal and maximal percolation time as well as on
the critical probability in the projective plane are also presented.


title:
Quantum Treatment of Kinetic Alfv\'en Waves instability in a dusty
  plasma: Magnetized ions

abstract:
  The dispersion relation of kinetic Alfv\'en wave in inertial regime is
studied in a three component non-degenerate streaming plasma. A lin- ear
dispersion relation using fluid- Vlasov equation for quantum plasma is also
derived. The quantum correction CQ raised due to the insertion of Bohm
potential in Vlasov model causes the suppression in the Alfven wave frequency
and the growth rates of instability. A number of analytical expressions are
derived for various modes of propagation. It is also found that many system
parameters, i.e, streaming velocity, dust charge, num- ber density and quantum
correction significantly influence the dispersion relation and the growth rate
of instability.


title: Decision and optimization problems in the Unreliable-Circuit Logic

abstract:
  The ambition constrained validity and the model witness problems in the logic
UCL, for reasoning about circuits with unreliable gates, are analyzed.
Moreover, two additional problems, motivated by the applications, are studied.
One consists of finding bounds on the reliability rate of the gates that ensure
that a given circuit has an intended success rate. The other consists of
finding a reliability rate of the gates that maximizes the success rate of a
given circuit. Sound and complete algorithms are developed for these problems
and their computational complexity is studied.


title: Inhomogeneous Cosmology Redux

abstract:
  An alternative to the postulate of dark energy required to explain the
accelerated expansion of the universe is to adopt an inhomogeneous cosmological
model to explain the supernovae data without dark energy. We adopt a void
cosmology model, based on the inhomogeneous Lema\^{i}tre-Tolman-Bondi solution
of Einstein's field equations. The model can resolve observational anomalies in
the $\Lambda CDM$ model, such as the discrepancy between the locally measured
value of the Hubble constant, $H_0=73.24\pm 1.74\,{\rm km}\,{\rm s}^{-1}\,{\rm
Mpc}^{-1}$, and the $H_0=66.93\pm 0.62\,{\rm km}\,{\rm s}^{-1}\,{\rm Mpc}^{-1}$
determined by the Planck satellite data and the $\Lambda CDM$ model, and the
lithium $^{7}{\rm Li}$ problem, which is a $5\sigma$ mismatch between the
theoretical prediction for the $^{7}{\rm Li}$ from big bang nucleosynthesis and
the value that we observe locally today at $z=0$. The void model can also
resolve the tension between the number of massive clusters derived from the
Sunyaev-Zel'dovich effect by the Planck satellite and the number expected from
the CMB anisotropies, and the CMB weak lensing anomaly observed in the Planck
data. The cosmological Copernican principle and the time and position today
coincidence conundrums in the $\Lambda CDM$ and void cosmological models are
discussed.


title:
Estimating Propensity Parameters using Google PageRank and Genetic
  Algorithms

abstract:
  Stochastic Boolean networks, or more generally, stochastic discrete networks,
are an important class of computational models for molecular interaction
networks. The stochasticity stems from the updating schedule. Standard updating
schedules include the synchronous update, where all the nodes are updated at
the same time, and the asynchronous update where a random node is updated at
each time step. The former produces a deterministic dynamics while the latter a
stochastic dynamics. A more general stochastic setting considers propensity
parameters for updating each node. Stochastic Discrete Dynamical Systems (SDDS)
is a modeling framework that considers two propensity parameters for updating
each node and uses one when the update has a positive impact on the variable,
that is, when the update causes the variable to increase its value, and uses
the other when the update has a negative impact, that is, when the update
causes it to decrease its value. This framework offers additional features for
simulations but also adds a complexity in parameter estimation of the
propensities. This paper presents a method for estimating the propensity
parameters for SDDS. The method is based on adding noise to the system using
the Google PageRank approach to make the system ergodic and thus guaranteeing
the existence of a stationary distribution. Then with the use of a genetic
algorithm, the propensity parameters are estimated. Approximation techniques
that make the search algorithms efficient are also presented and Matlab/Octave
code to test the algorithms are available at
http://www.ms.uky.edu/~dmu228/GeneticAlg/Code.html.


title: Accelerating Science TRIZ inventive methodology in illustrations

abstract:
  Theory of Inventive Problem Solving (TRIZ) is a powerful tool widely used in
engineering community. It is based on identification of a physical
contradiction in a problem, and based on the corresponding pair of
contradicting parameters selecting a few of suitable inventive principles,
narrowing down the choice and leading to a much faster solution of a problem.
It is remarkable that TRIZ methodology can also be applied to scientific
disciplines. Many of TRIZ inventive principles can be post factum identified in
various in scientific inventions and discoveries. However, additional inventive
principles, more suitable for scientific disciplines, should be introduced and
added to standard TRIZ, and some of the standard inventive principles need to
be reformulated to be better applicable to science - we call this extension
Accelerating Science TRIZ. In this short note we describe and illustrate the
AS-TRIZ inventive principles via scientific examples, identifying AS-TRIZ
inventive principles in discoveries and inventions originated from physics,
biology, and other areas. This brief note, we believe, is yet one more step
towards bringing TRIZ methodology closer into the scientific community.


title: Interferometry and Holography With Diode Laser Light

abstract:
  We made an interferometric Michelson type setup and a simple holographic
setup to demonstrate the feasibility of interferometric and holographic
techniques by means of a diode laser. The laser was made by using a common
diode available as a penlight element (less than R$ 15,00 value) and a simple
stabilized 110 VCA- 3 VCC power supply. Interference fringes and holograms of
small objects where obtained very similar to those of a helium-neon laser based
setup.


title:
Directional Statistics of Preferential Orientations of Two Shapes in
  Their Aggregate and Its Application to Study Preferential Attachment of
  Nanoparticles

abstract:
  Nanoscientists have long conjectured that adjacent nanoparticles aggregate
with one another in certain preferential directions during a chemical synthesis
of nanoparticles, which is referred to the oriented attachment. For the study
of the oriented attachment, the microscopy and nanoscience communities have
used dynamic electron microscopy for direct observations of nanoparticle
aggregation and have been so far relying on manual and qualitative analysis of
the observations. We propose a statistical approach for studying the oriented
attachment quantitatively with multiple aggregation examples in imagery
observations. We abstract an aggregation by an event of two primary geometric
objects merging into a secondary geometric object. We use a point set
representation to describe the geometric features of the primary objects and
the secondary object, and formulated the alignment of two point sets to one
point set to estimate the orientation angles of the primary objects in the
secondary object. The estimated angles are used as data to estimate the
probability distribution of the orientation angles and test important
hypotheses statistically. The proposed approach was applied for our motivating
example, which demonstrated that nanoparticles of certain geometries have
indeed preferential orientations in their aggregates.


title: A Binary Representation of the Genetic Code

abstract:
  This article introduces a novel binary representation of the canonical
genetic code based on both the structural similarities of the nucleotides, as
well as the physicochemical properties of the encoded amino acids. Each of the
four mRNA bases is assigned a unique 2-bit identifier, so that the 64 triplet
codons are each indexed by a 6-bit label. The ordering of the bits reflects the
hierarchical organization manifested by the DNA replication/repair and tRNA
translation systems. In this system, transition and transversion mutations are
naturally expressed as binary operations, and the severities of the different
point mutations can be analyzed. Using a principal component analysis, it is
shown that the physicochemical properties of amino acids related to protein
folding also correlate with certain bit positions of their respective labels.
Thus, the likelihood for a point mutation to be conservative, and less likely
to cause a change in protein functionality, can be estimated.


title: Trace test

abstract:
  The trace test in numerical algebraic geometry verifies the completeness of a
witness set of an irreducible variety in affine or projective space. We give a
brief derivation of the trace test and then consider it for subvarieties of
products of projective spaces using multihomogeneous witness sets. We show how
a dimension reduction leads to a practical trace test in this case involving a
curve in a low-dimensional affine space.


title:
An Asymptotic Preserving method for strongly anisotropic diffusion
  equations based on field line integration

abstract:
  In magnetized plasma, the magnetic field confines the particles around the
field lines. The anisotropy intensity in the viscosity and heat conduction may
reach the order of $10^{12}$. When the boundary conditions are periodic or
Neumann, the strong diffusion leads to an ill-posed limiting problem. To remove
the ill-conditionedness in the highly anisotropic diffusion equations, we
introduce a simple but very efficient asymptotic preserving reformulation in
this paper. The key idea is that, instead of discretizing the Neumann boundary
conditions locally, we replace one of the Neumann boundary condition by the
integration of the original problem along the field line, the singular
$1/\epsilon$ terms can be replaced by $O(1)$ terms after the integration, so
that yields a well-posed problem. Small modifications to the original code are
required and no change of coordinates nor mesh adaptation are needed.
  Uniform convergence with respect to the anisotropy strength $1/\epsilon$ can
be observed numerically and the condition number does not scale with the
anisotropy.


title:
SMILE Microscopy : fast and single-plane based super-resolution volume
  imaging

abstract:
  Fast 3D super-resolution imaging is essential for decoding rapidly occurring
biological processes. Encoding single molecules to their respective planes
enable simultaneous multi-plane super-resolution volume imaging. This saves the
data-acquisition time and as a consequence reduce radiation-dose that lead to
photobleaching and other undesirable photochemical reactions. Detection and
subsequent identification of the locus of individual molecule (both on the
focal plane and off-focal planes) holds the key. Experimentally, this is
achieved by accurate calibration of system PSF size and its natural spread in
off-focal planes using sub-diffraction fluorescent beads. Subsequently the
identification and sorting of single molecules that belong to different axial
planes is carried out (by setting multiple cut-offs to respective PSFs).
Simultaneous Multiplane Imaging based Localization Encoded (SMILE) microscopy
technique eliminates the need for multiple z-plane scanning and thereby
provides a truly simultaneous multiplane super-resolution imaging.


title: Fillability of small Seifert fibered spaces

abstract:
  On small Seifert fibered spaces $M(e_0;r_1,r_2,r_3)$ with $e_0\neq-1,-2,$ all
tight contact structures are Stein fillable. This is not the case for $e_0=-1$
or $-2$. However, for negative twisting structures it is expected that they are
all symplectically fillable. Here, we characterize fillable structures among
zero-twisting contact structures on small Seifert fibered spaces of the form
$M(-1;r_1,r_2,r_3)$. The result is obtained by analyzing monodromy
factorizations of associated planar open books.


title:
Mesostructure anisotropy of bacterial cellulose-polyacrylamide hydrogels
  as studied by spin-echo small-angle neutron scattering

abstract:
  The submicron- and micron-scale structures of composite hydrogels based on
bacterial cellulose (BC) and polyacrylamide were studied by spin-echo
small-angle neutron scattering (SESANS). These hydrogels were synthesized via
free-radical polymerization of acrylamide carried out in pellicle of BC swollen
in the reaction solution. No neutron scattering was observed for the samples
swollen in heavy water to the equilibrium state, but a SESANS signal appeared
when TbCl$_{3}$ salt was added to the solvent. The SESANS dependences obtained
for these samples revealed the anisotropy of mesostructure for the hydrogels
under investigation. Density inhomogeneities on the characteristic scale of
11.5 $\pm$ 0.5 $\mu$m were detected in one specific orientation of the sample,
i.e. with growth plane of BC parallel to plane formed by neutron beam and
spin-echo length. The uniaxial anisotropy revealed agrees with the proposed
model, which attributes this behavior to the existence of the tunnel-like
oriented structures inside BC.


title: Noncollinear Antiferromagnetic Haldane Magnon Insulator

abstract:
  In this Letter we present a comprehensive study of topological magnon bands
and thermal Hall effect in non-collinear antiferromagnetic systems on the
honeycomb lattice with an intrinsic Dzyaloshinskii-Moriya interaction. We
theoretically show that the system possesses topological magnon bands with
Chern number protected edge modes accompanied by a nonzero thermal magnon Hall
effect. These features result from non-collinearity of the magnetic moments due
to an applied out-of-plane magnetic field. Our results provide an experimental
clue towards the realization of topological magnon transports in honeycomb
antiferromagnetic compounds such as XPS$_3$ (X=Mn,Fe) and
$\alpha$-Cu$_2$V$_2$O$_7$.


title:
A probabilistic demand side management approach by consumption admission
  control

abstract:
  New generation electricity network called Smart Grid is a recently conceived
vision for a cleaner, more efficient and cheaper electricity system. One of the
major challenges of electricity network is that generation and consumption
should be balanced at every moment. This paper introduces a new concept for
controlling the demand side by the means of automatically enabling/disabling
electric appliances to make sure that the demand is in match with the available
supplies, based on the statistical characterization of the need. In our new
approach instead of using hard limits we estimate the tail probability of the
demand distribution and control system by using the principles and the results
of statistical resource management.


title:
Collisional interactions between self-interacting non-relativistic boson
  stars: effective potential analysis and numerical simulations

abstract:
  Scalar particles are a common prediction of many beyond the Standard Model
theories. If they are light and cold enough, there is a possibility they may
form Bose-Einstein condensates, which will then become gravitationally bound.
These boson stars are solitonic solutions to the Einstein-Klein-Gordon
equations, but may be approximated in the non-relativistic regime with a
coupled Schr\"odinger-Poisson system. General properties of single soliton
states are derived, including the possibility of quartic self-interactions.
Binary collisions between two solitons are then studied, and the effects of
different mass ratios, relative phases, self-couplings, and separation
distances are characterized, leading to an easy conceptual understanding of how
these parameters affect the collision outcome in terms of conservation of
energy. Applications to dark matter are discussed.


title:
QBism, FAPP and the Quantum Omelette. (Or, Unscrambling Ontological
  Problems from Epistemological Solutions in QM)

abstract:
  In this paper we discuss the so called "quantum omelette" created by Bohr and
Heisenberg through the mix of (ontic) objective accounts and (epistemic)
subjective ones within the analysis of Quantum Mechanics (QM). We will begin by
addressing the difficult relation between ontology and epistemology within the
history of both physics and philosophy. We will then argue that the present
"quantum omelette" is being presently cooked in two opposite directions: the
first scrambling ontological problems with epistemological solutions and the
second scrambling epistemic approaches with ontological questions. A good
example of the former is a new type of argumentation strategy attempting to
justify the use of decoherence, namely, the "For All Practical Purposes"
(shortly known as FAPP) type of justification. We will argue that 'FAPP-type
solutions' remain, at best, epistemological answers which not only escape the
ontological questions at stake -regarding the quantum to classical limit- but
also turn the original problem completely meaningless. The latter omelette can
be witnessed in relation to some criticisms raised against the epistemic
Bayesian approach to QM (shortly known as QBism). We will argue that QBists
have produced a consistent scheme that might allow us to begin to unscramble
-at least part of- the "quantum omelette". In this respect, we will show why
the epistemic QBist approach is safe from several (ontological) criticisms it
has recently received (see [42, 47, 48]). We end our paper with a discussion
about the importance of ontological approaches within foundations of QM.


title:
Spectroscopic Evolution of Disintegrating Planetesimals: Minutes to
  Months Variability in the Circumstellar Gas Associated with WD 1145+017

abstract:
  With the recent discovery of transiting planetary material around WD
1145+017, a critical target has been identified that links the evolution of
planetary systems with debris disks and their accretion onto the star. We
present a series of observations, five epochs over a year, taken with Keck and
the VLT, which for the first time show variability of circumstellar absorption
in the gas disk surrounding WD 1145+017 on timescales of minutes to months.
Circumstellar absorption is measured in more than 250 lines of 14 ions among
ten different elements associated with planetary composition, e.g., O, Mg, Ca,
Ti, Cr, Mn, Fe, Ni. Broad circumstellar gas absorption with a velocity spread
of 225 km/s is detected, but over the course of a year blue shifted absorption
disappears while redshifted absorption systematically increases. A correlation
of equivalent width and oscillator strength indicates that the gas is not
highly optically thick (median tau approximately 2). We discuss simple models
of an eccentric disk coupled with magnetospheric accretion to explain the basic
observed characteristics of these high resolution and high signal-to-noise
observations. Variability is detected on timescales of minutes in the two most
recent observations, showing a loss of redshifted absorption for tens of
minutes, coincident with major transit events and consistent with gas hidden
behind opaque transiting material. This system currently presents a unique
opportunity to learn how the gas causing the spectroscopic, circumstellar
absorption is associated with the ongoing accretion evidenced by photospheric
contamination, as well as the transiting planetary material detected in
photometric observations.


title: Theory of the GMM Kernel

abstract:
  We develop some theoretical results for a robust similarity measure named
"generalized min-max" (GMM). This similarity has direct applications in machine
learning as a positive definite kernel and can be efficiently computed via
probabilistic hashing. Owing to the discrete nature, the hashed values can also
be used for efficient near neighbor search. We prove the theoretical limit of
GMM and the consistency result, assuming that the data follow an elliptical
distribution, which is a very general family of distributions and includes the
multivariate $t$-distribution as a special case. The consistency result holds
as long as the data have bounded first moment (an assumption which essentially
holds for datasets commonly encountered in practice). Furthermore, we establish
the asymptotic normality of GMM. Compared to the "cosine" similarity which is
routinely adopted in current practice in statistics and machine learning, the
consistency of GMM requires much weaker conditions. Interestingly, when the
data follow the $t$-distribution with $\nu$ degrees of freedom, GMM typically
provides a better measure of similarity than "cosine" roughly when $\nu<8$
(which is already very close to normal). These theoretical results will help
explain the recent success of GMM in learning tasks.


title:
Simulated forecasts for primordial B-mode searches in ground-based
  experiments

abstract:
  Detecting the imprint of inflationary gravitational waves on the $B$-mode
polarization of the Cosmic Microwave Background (CMB) is one of the main
science cases for current and next-generation CMB experiments. In this work we
explore some of the challenges that ground-based facilities will have to face
in order to carry out this measurement in the presence of Galactic foregrounds
and correlated atmospheric noise. We present forecasts for Stage-3 (S3) and
planned Stage-4 (S4) experiments based on the analysis of simulated sky maps
using a map-based Bayesian foreground cleaning method. Our results thus
consistently propagate the uncertainties on foreground parameters such as
spatially-varying spectral indices, as well as the bias on the measured
tensor-to-scalar ratio $r$ caused by an incorrect modelling of the foregrounds.
We find that S3 and S4-like experiments should be able to put constraints on
$r$ of the order $\sigma(r)=(0.5-1.0)\times10^{-2}$ and
$\sigma(r)=(0.5-1.0)\times10^{-3}$ respectively, assuming instrumental
systematic effects are under control. We further study deviations from the
fiducial foreground model, finding that, while the effects of a second
polarized dust component would be minimal on both S3 and S4, a 2\% polarized
anomalous dust emission (AME) component would be clearly detectable by Stage-4
experiments.


title:
Scattering of massless scalar waves by magnetically charged black holes
  in Einstein-Yang-Mills-Higgs theory

abstract:
  The existence of the classical black hole solutions of the
Einstein-Yang-Mills-Higgs equations with non-abelian Yang-Mills-Higgs hair,
which we will also refer to as "magnetic monopole black hole solutions",
implies that not all classical stationary magnetically charged black holes can
be uniquely described by their asymptotic characteristics. In fact, in a
certain domain of parameters, there exist different spherically-symmetric,
non-rotating and asymptotically-flat classical black hole solutions of the EYMH
equations which have the same ADM mass and the same magnetic charge but
significantly different geometries in the near-horizon regions. (These are
black hole solutions which are described by a Reissner-Nordstr\"om metric on
the one hand and the hairy magnetic monopole black hole solutions which are
described by a metric which is not of Reissner-Nordstr\"om form on the other
hand.) One can experimentally distinguish such black holes with same asymptotic
characteristics but different near-horizon geometries classically by probing
the near-horizon regions of the black holes. We argue that one way to probe the
near-horizon region of a black hole which allows to distinguish magnetically
charged black holes with same asymptotic characteristics but different
near-horizon geometries is by classical scattering of waves. Using the example
of a minimally-coupled massless probe scalar field scattered by magnetically
charged black holes which can be obtained as solutions of the EYMH equations
with a Higgs triplett and gauge group SU(2) in the limit of an infinite Higgs
self-coupling constant we show how, in this case, the scattering cross sections
differ for the magnetically charged black holes with different near-horizon
geometries but same asymptotic characteristics. We find in particular that the
characteristic glory peaks in the cross sections are located at different
scattering angles.


title: Sparse image reconstruction on the sphere: analysis and synthesis

abstract:
  We develop techniques to solve ill-posed inverse problems on the sphere by
sparse regularisation, exploiting sparsity in both axisymmetric and directional
scale-discretised wavelet space. Denoising, inpainting, and deconvolution
problems, and combinations thereof, are considered as examples. Inverse
problems are solved in both the analysis and synthesis settings, with a number
of different sampling schemes. The most effective approach is that with the
most restricted solution-space, which depends on the interplay between the
adopted sampling scheme, the selection of the analysis/synthesis problem, and
any weighting of the l1 norm appearing in the regularisation problem. More
efficient sampling schemes on the sphere improve reconstruction fidelity by
restricting the solution-space and also by improving sparsity in wavelet space.
We apply the technique to denoise Planck 353 GHz observations, improving the
ability to extract the structure of Galactic dust emission, which is important
for studying Galactic magnetism.


title: On the Complexity of Constrained Determinantal Point Processes

abstract:
  Determinantal Point Processes (DPPs) are probabilistic models that arise in
quantum physics and random matrix theory and have recently found numerous
applications in computer science. DPPs define distributions over subsets of a
given ground set, they exhibit interesting properties such as negative
correlation, and, unlike other models, have efficient algorithms for sampling.
When applied to kernel methods in machine learning, DPPs favor subsets of the
given data with more diverse features. However, many real-world applications
require efficient algorithms to sample from DPPs with additional constraints on
the subset, e.g., partition or matroid constraints that are important to ensure
priors, resource or fairness constraints on the sampled subset. Whether one can
efficiently sample from DPPs in such constrained settings is an important
problem that was first raised in a survey of DPPs by \cite{KuleszaTaskar12} and
studied in some recent works in the machine learning literature.
  The main contribution of our paper is the first resolution of the complexity
of sampling from DPPs with constraints. We give exact efficient algorithms for
sampling from constrained DPPs when their description is in unary. Furthermore,
we prove that when the constraints are specified in binary, this problem is
#P-hard via a reduction from the problem of computing mixed discriminants
implying that it may be unlikely that there is an FPRAS. Our results benefit
from viewing the constrained sampling problem via the lens of polynomials.
Consequently, we obtain a few algorithms of independent interest: 1) to count
over the base polytope of regular matroids when there are additional (succinct)
budget constraints and, 2) to evaluate and compute the mixed characteristic
polynomials, that played a central role in the resolution of the Kadison-Singer
problem, for certain special cases.


title:
Asymptotic formulas for the second moments of $L$-series associated to
  holomorphic cusp forms on the critical line

abstract:
  New uniform asymptotic formulas are obtained for the second moment of
$L$-series of cusp forms of even weight $2k\ge2$ with respect to the congruence
subgroup $\Gamma_0(N).$


title:
Vetting Galactic Leavitt Law Calibrators using Radial Velocities: On the
  Variability, Binarity, and Possible Parallax Error of 19 Long-period Cepheids

abstract:
  We investigate the radial velocity (RV) variability and spectroscopic
binarity of 19 Galactic long-period ($P_{\rm{puls}} \gtrsim 10$ d) classical
Cepheid variable stars whose trigonometric parallaxes are being measured using
the Hubble Space Telescope and Gaia. Our primary objective is to constrain
possible parallax error due to undetected orbital motion. Using $>1600$
high-precision RVs measured between 2011 and 2016, we find no indication of
orbital motion on $\lesssim 5$ yr timescales for 18 Cepheids and determine
upper limits on allowed configurations for a range of input orbital periods.
The results constrain the unsigned parallax error due to orbital motion to $< 2
\%$ for 16 stars, and $< 4 \%$ for 18. We improve the orbital solution of the
known binary YZ Carinae and show that the astrometric model must take into
account orbital motion to avoid significant error ($\sim \pm 100 \mu$arcsec).
We further investigate long-timescale ($P_{\rm{orb}} > 10$ yr) variations in
pulsation-averaged velocity $v_\gamma$ via a template fitting approach using
both new and literature RVs. We discover the spectroscopic binarity of XZ Car
and CD Cyg, find first tentative evidence for AQ Car, and reveal KN Cen's
orbital signature. Further (mostly tentative) evidence of time-variable
$v_\gamma$ is found for SS CMa, VY Car, SZ Cyg, and X Pup. We briefly discuss
considerations regarding a vetting process of Galactic Leavitt law calibrators
and show that light contributions by companions are insignificant for most
distance scale applications.


title:
Robust and Scalable Tracking of Radiation Sources with Cheap Binary
  Proximity Sensors

abstract:
  We present a new approach to tracking of radiation sources moving on smooth
trajectories which can be approximated with piece-wise linear joins or
piece-wise linear parabolas. We employ the use of cheap binary proximity
sensors which only indicate when a radiation source enters and leaves its
sensing range. We present two separate cases. The first is considering that the
trajectory can be approximated with piece-wise linear joins. We develop a novel
scalable approach in terms of the number of sensors required. Robustness
analysis is done with respect to uncertainties in the timing recordings by the
radiation sensors. We show that in the noise free case, a minimum of three
sensors will suffice to recover one piece of the linear join with probability
one, even in the absence of knowledge of the speed and statistics of the
radiation source. Second, we tackle a more realistic approximation of
trajectories of radiation sources -- piece-wise parabolic joins -- and show
that no more than six sensors are required in the noise free case to track one
piece of the parabola with probability one. Next we present an upper bound on
the achievable error variance in the estimation of the constant speed and the
angle of elevation of linear trajectories. Finally, a comprehensive set of
simulations are presented to illustrate the robustness of our approach in the
presence of uncertainties.


title:
A new look on the stabilization of inverted pendulum with parametric
  excitation and large random frequencies: analytical and numerical approaches

abstract:
  In this paper we explore the stability of an inverted pendulum with
generalized parametric excitation described by a superposition of $N$ sines
with different frequencies and phases. We show that when the amplitude is
scaled with the frequency we obtain the stabilization of the real inverted
pendulum, i.e., with values of $g$ according to planet Earth ($g\approx
9.8$m/s$^{2}$) for high frequencies. By randomly sorting the frequencies, we
obtain a critical amplitude in light of perturbative theory in classical
mechanics which is numerically tested by exploring its validity regime in many
alternatives. We also analyse the effects when different values of $N$ as well
as the pendulum size $l$ are taken into account.


title: Scattering of Fermions by Gravitons

abstract:
  The interaction between gravitons and fermions is investigated in the
teleparallel gravity. The scattering of fermions and gravitons in the weak
field approximation is analyzed. The transition amplitudes of
M$\varnothing$ller, Compton and new gravitational scattering are calculated.


title: Non-singular and Cyclic Universe from the Modified GUP

abstract:
  In this paper, we investigate the effects of a new version of the generalized
uncertainty principle (modified GUP) on the dynamics of the Universe. As the
modified GUP will modify the relation between the entropy and area of the
apparent horizon, it will also deform the Friedmann equations within Jacobson's
approach. We explicitly find these deformed Friedmann equations governing the
modified GUP-corrected dynamics of such a Universe. It is shown that the
modified GUP-deformed Jacobson's approach implies an upper bound for the
density of such a Universe. The Big Bang singularity can therefore also be
avoided using the modified GUP-corrections to horizons' thermodynamics. In
fact, we are able to analyze the pre Big Bang state of the Universe.
Furthermore, the equations imply that the expansion of the Universe will come
to a halt and then will immediately be followed by a contracting phase. When
the equations are extrapolated beyond the maximum rate of contraction, a cyclic
Universe scenario emerges.


title:
A PMT-like high gain avalanche photodiode based on GaN/AlN periodical
  stacked structure

abstract:
  Avalanche photodiode (APD) has been intensively investigated as a promising
candidate to replace photomultiplier tubes (PMT) for weak light detection.
However, in conventional APDs, a large portion of carrier energy drawn from the
electric field is thermalized, and the multiplication efficiencies of electron
and hole are low and close. In order to achieve high gain, the device should
work under breakdown bias, where carrier multiplication proceeds
bi-directionally to form a positive feedback multiplication circle. However,
breakdown is hard to control, in practice, APDs should work under Geiger mode
as a compromise between sustainable detection and high gain. The complexity of
system seriously restricts the application. Here, we demonstrate an avalanche
photodiode holding high gain without breakdown, which means no quenching
circuit is needed for sustainable detection. The device is based on a GaN/AlN
periodically-stacked-structure (PSS), wherein electron holds much higher
efficiency than hole to draw energy from the electric field, and avalanche
happens uni-directionally with high efficiency. and a recorded high gain (10^4)
tested under constant bias is obtained in a prototype device, wherein the
stable gain can be determined by the periodicity of the GaN/AlN PSS. This work
not only brings a new light into avalanche multiplication mechanism, but also
paves a technological path with high commercial value to realize highly
sensitive avalanche devices working under constant bias like PMT.


title: Long-term stability test of a triple GEM detector

abstract:
  The main aim of the study is to perform the long-term stability test of gain
of the single mask triple GEM detector. A simple method is used for this long-
term stability test using a radioactive X-ray source with high activity. The
test is continued till accumulation of charge per unit area > 12.0 mC/mm2. The
details of the chamber fabrication, the test set-up, the method of measurement
and the test results are presented in this paper.


title: Building of a 4-channel TTL scaler for counting detector signals

abstract:
  A scaler has been fabricated to count the signals from any radiation de-
tector. It can count signals of frequency up to 140 kHz. Transistor Transistor
Logic (TTL) is used in this scaler. In this article the details of the design,
fabrication and operation processes of the scaler is presented.


title: Sasaki-Einstein 7-Manifolds, Orlik Polynomials and Homology

abstract:
  Let $L_f$ be a link of an isolated hypersurface singularity defined by a
weighted homogenous polynomial $f.$ In this article, we give ten examples of
$2$-connected seven dimensional Sasaki-Einstein manifolds $L_f$ for which
$H_{3}(L_f, \mathbb{Z})$ is completely determined. Using the Boyer-Galicki
construction of links $L_f$ over particular K\"ahler-Einstein orbifolds, we
apply a valid case of Orlik's conjecture to the links $L_f $ so that one is
able to explicitly determine $H_{3}(L_f,\mathbb{Z}).$ We give ten such new
examples, all of which have the third Betti number satisfy $10\leq
b_{3}(L_{f})\leq 20$.


title:
X-ray powder diffraction of high-absorption materials at the XRD1
  beamline off the best conditions: Application to (Gd,Nd)5Si4 compounds

abstract:
  Representative compounds of the new family of magnetic materials Gd5-xNdxSi4
were analyzed by X-ray diffraction at the XRD1 beamline at LNLS. To reduce
X-ray absorption, thin layers of the powder samples were mounted outside the
capillaries and measured in Debye-Scherrer geometry as usual. The X-ray
diffraction analyses and the magnetometry results indicate that the behavior of
the magnetic transition temperature as a function of Nd content may be directly
related to the average of the four smallest interatomic distances between
different rare earth sites of the majority phase of each compound. The quality
and consistency of the results show that the XRD1 beamline is able to perform
satisfactory X-ray diffraction experiments on high-absorption materials even
off the best conditions.


title: Compact stars in $f(R,T)$ gravity

abstract:
  In the present paper we generate a set of solutions describing the interior
of a compact star under $f(R,T)$ theory of gravity which admits conformal
motion. We consider the equation of state (EOS) $p=\omega\rho$ with
$0<\omega<1$ for the fluid distribution consisting normal matter, $\omega$
being the EOS parameter. We therefore explore several aspects of the model
analytically along with graphical representations to check the physical
validity as well as acceptability of it within specified observational
constraint in connection to a dozen of the compact star candidates. It is shown
from the presented model that these objects are nothing but radiating compact
stars.


title:
Identification of repeats in DNA sequences using nucleotide distribution
  uniformity

abstract:
  Repetitive elements are important in genomic structures, functions and
regulations, yet effective methods in precisely identifying repetitive elements
in DNA sequences are not fully accessible, and the relationship between
repetitive elements and periodicities of genomes is not clearly understood. We
present an $\textit{ab initio}$ method to quantitatively detect repetitive
elements and infer the consensus repeat pattern in repetitive elements. The
method uses the measure of the distribution uniformity of nucleotides at
periodic positions in DNA sequences or genomes. It can identify periodicities,
consensus repeat patterns, copy numbers and perfect levels of repetitive
elements. The results of using the method on different DNA sequences and
genomes demonstrate efficacy and accuracy in identifying repeat patterns and
periodicities. The complexity of the method is linear with respect to the
lengths of the analyzed sequences.


title:
Spectral Identification of the u-band Variable Sources in Two LAMOST
  fields

abstract:
  We selected 82 u-band variable objects based on the u-band photometry data
from SCUSS and SDSS, in the field of LAMOST Complete Spectroscopic Survey of
Pointing Area at Southern Galactic Cap. The magnitude variation of the targets
is restricted to larger than 0.2 mag and limiting magnitude down to 19.0 mag in
u-band. According to the spectra from LAMOST, there are 11 quasars with
red-shift between 0.4 and 1.8, 60 variable stars and 11 unidentified targets.
The variable stars include one active M-dwarf with a series of Balmer emission
lines, seven Horizontal Branch stars containing six RR Lyrae stars matching
with SIMBAD, and one giant, one AGB star and two RR Lyrae candidates by
different colour selections. All these variable stars mainly locate near the
main sequence in the g-r verse u-g diagram. The quasars are well distinguished
from stars by both u-g colour and variation in u-band.


title:
Graphene-based, mid-infrared, room-temperature pyroelectric bolometers
  with ultrahigh temperature coefficient of resistance

abstract:
  Graphene is ideally suited for photonic and optoelectronic applications, with
a variety of photodetectors (PDs) in the visible, near-infrared (NIR), and THz
reported to date, as well as thermal detectors in the mid-infrared (MIR). Here,
we present a room temperature-MIR-PD where the pyroelectric response of a
LiNbO3 crystal is transduced with high gain (up to 200) into resistivity
modulation for graphene, leading to a temperature coefficient of resistance up
to 900%/K, two orders of magnitude higher than the state of the art, for a
device area of 300x300um2. This is achieved by fabricating a floating metallic
structure that concentrates the charge generated by the pyroelectric substrate
on the top-gate capacitor of the graphene channel. This allows us to resolve
temperature variations down to 15umK at 1 Hz, paving the way for a new
generation of detectors for MIR imaging and spectroscopy


title: A Methodology to Generate Virtual Patient Repositories

abstract:
  Electronic medical records (EMR) contain sensitive personal information. For
example, they may include details about infectious diseases, such as human
immunodeficiency virus (HIV), or they may contain information about a mental
illness. They may also contain other sensitive information such as medical
details related to fertility treatments. Because EMRs are subject to
confidentiality requirements, accessing and analyzing EMR databases is a
privilege given to only a small number of individuals. Individuals who work at
institutions that do not have access to EMR systems have no opportunity to gain
hands-on experience with this valuable resource. Simulated medical databases
are currently available; however, they are difficult to configure and are
limited in their resemblance to real clinical databases. Generating highly
accessible repositories of virtual patient EMRs while relying only minimally on
real patient data is expected to serve as a valuable resource to a broader
audience of medical personnel, including those who reside in underdeveloped
countries.


title:
TREES: A CPU/GPU Task-Parallel Runtime with Explicit Epoch
  Synchronization

abstract:
  We have developed a task-parallel runtime system, called TREES, that is
designed for high performance on CPU/GPU platforms. On platforms with multiple
CPUs, Cilk's "work-first" principle underlies how task-parallel applications
can achieve performance, but work-first is a poor fit for GPUs. We build upon
work-first to create the "work-together" principle that addresses the specific
strengths and weaknesses of GPUs. The work-together principle extends
work-first by stating that (a) the overhead on the critical path should be paid
by the entire system at once and (b) work overheads should be paid
co-operatively. We have implemented the TREES runtime in OpenCL, and we
experimentally evaluate TREES applications on a CPU/GPU platform.


title:
An end-to-end network slicing framework for 5G wireless communication
  systems

abstract:
  Wireless industry nowadays is facing two major challenges: 1) how to support
the vertical industry applications so that to expand the wireless industry
market and 2) how to further enhance device capability and user experience. In
this paper, we propose a technology framework to address these challenges. The
proposed technology framework is based on end-to-end vertical and horizontal
slicing, where vertical slicing enables vertical industry and services and
horizontal slicing improves system capacity and user experience. The technology
development on vertical slicing has already started in late 4G and early 5G and
is mostly focused on slicing the core network. We envision this trend to
continue with the development of vertical slicing in the radio access network
and the air interface. Moving beyond vertical slicing, we propose to
horizontally slice the computation and communication resources to form virtual
computation platforms for solving the network capacity scaling problem and
enhancing device capability and user experience. In this paper, we explain the
concept of vertical and horizontal slicing and illustrate the slicing
techniques in the air interface, the radio access network, the core network and
the computation platform. This paper aims to initiate the discussion on the
long-range technology roadmap and spur development on the solutions for E2E
network slicing in 5G and beyond.


title:
The Influence of Magnetic Field Geometry on the Formation of Close-in
  Exoplanets

abstract:
  Approximately half of Sun-like stars harbor exoplanets packed within a radius
of ~0.3 AU, but the formation of these planets and why they form in only half
of known systems are still not well understood. We employ a one-dimensional
steady state model to gain physical insight into the origin of these close-in
exoplanets. We use Shakura & Sunyaev alpha values extracted from recent
numerical simulations of protoplanetary disk accretion processes in which the
magnitude of alpha, and thus the steady-state gas surface density, depends on
the orientation of large scale magnetic fields with respect to the disk's
rotation axis. Solving for the metallicity as a function of radius, we find
that for fields anti-aligned with the rotation axis, the inner regions of our
model disk often falls within a region of parameter space not suitable for
planetesimal formation, whereas in the aligned case, the inner disk regions are
likely to produce planetesimals through some combination of streaming
instability and gravitational collapse, though the degree to which this is true
depends on the assumed parameters of our model. More robustly, the aligned
field case always produces higher concentrations of solids at small radii
compared to the anti-aligned case. In the in situ formation model, this bimodal
distribution of solid enhancement leads directly to the observed dichotomy in
exoplanet orbital distances.


title: Observing the Top Energy Asymmetry at the LHC

abstract:
  The top-antitop energy asymmetry is a promising observable of the charge
asymmetry in jet-associated top-quark pair production at the LHC. We present
new predictions of the energy asymmetry in proton-proton collisions at 13 TeV,
including QCD corrections at the next-to-leading perturbative order. The effect
of QCD corrections on the observable is moderate. With suitable phase-space
cuts, the asymmetry can be enhanced at the cost of reducing the cross section.
For instance, for a cross section of $1\,\text{pb}$ after cuts, we predict an
energy asymmetry of $-6.5^{\,+0.1}_{\,-0.2}\%$ at the next-to-leading order in
QCD. We also investigate scale uncertainties and parton-shower effects, which
partially cancel in the normalized asymmetry. Our results provide a sound basis
for a measurement of the energy asymmetry at the LHC during run II.


title:
The Robo-AO KOI Survey: laser adaptive optics imaging of every Kepler
  exoplanet candidate

abstract:
  The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler
planet candidate host star (KOI) with laser adaptive optics imaging to hunt for
blended nearby stars which may be physically associated companions. With the
unparalleled efficiency provided by the first fully robotic adaptive optics
system, we perform the critical search for nearby stars (0.15" to 4.0"
separation with contrasts up to 6 magnitudes) that dilute the observed
planetary transit signal, contributing to inaccurate planetary characteristics
or astrophysical false positives. We present 3313 high resolution observations
of Kepler planetary hosts from 2012-2015, discovering 479 nearby stars. We
measure an overall nearby star probability rate of 14.5\pm0.8%. With this large
data set, we are uniquely able to explore broad correlations between multiple
star systems and the properties of the planets which they host, providing
insight into the formation and evolution of planetary systems in our galaxy.
Several KOIs of particular interest will be discussed, including possible
quadruple star systems hosting planets and updated properties for possible
rocky planets orbiting with in their star's habitable zone.


title: Anomalous Double-Mode RR Lyrae Stars in the Magellanic Clouds

abstract:
  We report the discovery of a new subclass of double-mode RR Lyrae stars in
the Large and Small Magellanic Clouds. The sample of 22 pulsating stars have
been extracted from the latest edition of the OGLE collection of RR Lyrae
variables in the Magellanic System. The stars pulsating simultaneously in the
fundamental (F) and first-overtone (1O) modes have distinctly different
properties than regular double-mode RR Lyrae variables (RRd stars). The
$P_{1O}/P_F$ period ratios of our anomalous RRd stars are within a range
0.725-0.738, while "classical" double-mode RR Lyrae variables have period
ratios in the range 0.742-0.748. In contrast to the typical RRd stars, in the
majority of the anomalous pulsators the F-mode amplitudes are higher than the
1O-mode amplitudes. The light curves associated with the F-mode in the
anomalous RRd stars show different morphology than the light curves of, both,
regular RRd stars and single-mode RRab stars. Most of the anomalous double-mode
stars show long-term modulations of the amplitudes (Blazhko-like effect).
Translating the period ratios into the abundance parameter, Z, we find for our
stars Z in the range (0.002,0.005) - an order of magnitude higher values than
typical for RR Lyrae stars. The mass range of the RRd stars inferred from the
$W_I$ vs. $P_F$ diagram is (0.55-0.75) of the solar mass. These parameters
cannot be accounted for with single star evolution assuming a Reimers-like mass
loss. Much greater mass loss caused by interaction with other stars is
postulated. We blame the peculiar pulsation properties of our stars to the
parametric resonance instability of the 1O-mode to excitation of the F- and
2O-modes as with the inferred parameters of the stars $2\omega_{\rm
1O}\approx\omega_{\rm F}+\omega_{\rm 2O}$.


title: Fermionic WIMPs and Vacuum Stability in the Scotogenic Model

abstract:
  We demonstrate that the condition of vacuum stability severely restricts
scenarios with fermionic WIMP dark matter in the scotogenic model. The sizable
Yukawa couplings that are required to satisfy the dark matter constraint via
thermal freeze-out in these scenarios tend to destabilise the vacuum at scales
below that of the heaviest singlet fermion, rendering the model inconsistent
from a theoretical point of view. By means of a scan over the parameter space,
we study the impact of these renormalisation group effects on the viable
regions of this model. Our analysis shows that a fraction of more than 90% of
the points compatible with all known experimental constraints - including
neutrino masses, the dark matter density, and lepton flavour violation - is
actually inconsistent.


title: Planet Formation Imager (PFI): science vision and key requirements

abstract:
  The Planet Formation Imager (PFI) project aims to provide a strong scientific
vision for ground-based optical astronomy beyond the upcoming generation of
Extremely Large Telescopes. We make the case that a breakthrough in angular
resolution imaging capabilities is required in order to unravel the processes
involved in planet formation. PFI will be optimised to provide a complete
census of the protoplanet population at all stellocentric radii and over the
age range from 0.1 to about 100 Myr. Within this age period, planetary systems
undergo dramatic changes and the final architecture of planetary systems is
determined. Our goal is to study the planetary birth on the natural spatial
scale where the material is assembled, which is the "Hill Sphere" of the
forming planet, and to characterise the protoplanetary cores by measuring their
masses and physical properties. Our science working group has investigated the
observational characteristics of these young protoplanets as well as the
migration mechanisms that might alter the system architecture. We simulated the
imprints that the planets leave in the disk and study how PFI could
revolutionise areas ranging from exoplanet to extragalactic science. In this
contribution we outline the key science drivers of PFI and discuss the
requirements that will guide the technology choices, the site selection, and
potential science/technology tradeoffs.


title: SRAO: optical design and the dual-knife-edge WFS

abstract:
  The Southern Robotic Adaptive Optics (SRAO) instrument will bring the proven
high-efficiency capabilities of Robo-AO to the Southern-Hemisphere, providing
the unique capability to image with high-angular-resolution thousands of
targets per year across the entire sky. Deployed on the modern 4.1m SOAR
telescope located on Cerro Tololo, the NGS-AO system will use an innovative
dual-knife-edge wavefront sensor, similar to a pyramid sensor, to enable
guiding on targets down to V=16 with diffraction limited resolution in the NIR.
The dual-knife-edge wavefront sensor can be up to two orders of magnitude less
costly than custom glass pyramids, with similar wavefront error sensitivity and
minimal chromatic aberrations. SRAO is capable of observing hundreds of targets
a night through automation, allowing confirmation and characterization of the
large number of exoplanets produced by current and future missions.


title:
Architecture design study and technology roadmap for the Planet
  Formation Imager (PFI)

abstract:
  The Planet Formation Imager (PFI) Project has formed a Technical Working
Group (TWG) to explore possible facility architectures to meet the primary PFI
science goal of imaging planet formation in situ in nearby star- forming
regions. The goals of being sensitive to dust emission on solar system scales
and resolving the Hill-sphere around forming giant planets can best be
accomplished through sub-milliarcsecond imaging in the thermal infrared.
Exploiting the 8-13 micron atmospheric window, a ground-based long-baseline
interferometer with approximately 20 apertures including 10km baselines will
have the necessary resolution to image structure down 0.1 milliarcseconds
(0.014 AU) for T Tauri disks in Taurus. Even with large telescopes, this array
will not have the sensitivity to directly track fringes in the mid-infrared for
our prime targets and a fringe tracking system will be necessary in the
near-infrared. While a heterodyne architecture using modern mid-IR laser comb
technology remains a competitive option (especially for the intriguing 24 and
40{\mu}m atmospheric windows), the prioritization of 3-5{\mu}m observations of
CO/H2O vibrotational levels by the PFI-Science Working Group (SWG) pushes the
TWG to require vacuum pipe beam transport with potentially cooled optics. We
present here a preliminary study of simulated L- and N-band PFI observations of
a realistic 4-planet disk simulation, finding 21x2.5m PFI can easily detect the
accreting protoplanets in both L and N-band but can see non-accreting planets
only in L band. (abridged -- see PDF for full abstract)


title:
Electron Teleportation in Multi-Terminal Majorana Islands: Statistical
  Transmutation and Fractional Quantum Conductance

abstract:
  We study a topological superconductor island with spatially separated
Majorana modes coupled to multiple normal metal leads by single electron
tunneling in the Coulomb blockade regime. We show that low-temperature
transport in such Majorana island is carried by an emergent charge-$e$ boson
composed of a Majorana mode and an electron from the leads. This transmutation
from Fermi to Bose statistics has remarkable consequences. For noninteracting
leads, the system flows to a non-Fermi liquid fixed point, which is stable
against tunnel couplings anisotropy or detuning away from the charge-degeneracy
point. As a result, the system exhibits a universal conductance at zero
temperature, which is a fraction of the conductance quantum, and
low-temperature corrections with a universal power-law exponent. In addition,
we consider Majorana islands connected to interacting one-dimensional leads,
and find different stable fixed points near and far from the charge-degeneracy
point.


title: Status of the Planet Formation Imager (PFI) concept

abstract:
  The Planet Formation Imager (PFI) project aims to image the period of planet
assembly directly, resolving structures as small as a giant planet's Hill
sphere. These images will be required in order to determine the key mechanisms
for planet formation at the time when processes of grain growth, protoplanet
assembly, magnetic fields, disk/planet dynamical interactions and complex
radiative transfer all interact - making some planetary systems habitable and
others inhospitable. We will present the overall vision for the PFI concept,
focusing on the key technologies and requirements that are needed to achieve
the science goals. Based on these key requirements, we will define a cost
envelope range for the design and highlight where the largest uncertainties lie
at this conceptual stage.


title: Baryogenesis and Gravitational Waves from Runaway Bubble Collisions

abstract:
  We propose a novel mechanism for production of baryonic asymmetry in the
early Universe. The mechanism takes advantage of the strong first order phase
transition that produces runaway bubbles in the hidden sector that propagate
almost without friction with ultra-relativistic velocities. Collisions of such
bubbles can non-thermally produce heavy particles that further decay
out-of-equilibrium into the SM and produce the observed baryonic asymmetry.
This process can proceed at the very low temperatures, providing a new
mechanism of post-sphaleron baryogenesis. In this paper we present a fully
calculable model which produces the baryonic asymmetry along these lines as
well as evades all the existing cosmological constraints. We emphasize that the
Gravitational Waves signal from the first order phase transition is completely
generic and can potentially be detected by the future eLISA interferometer. We
also discuss other potential signals, which are more model dependent, and point
out the unresolved theoretical questions related to our proposal.


title: Temperature effects in the band structure of topological insulators

abstract:
  We study the effects of temperature on the band structure of the Bi$_2$Se$_3$
family of topological insulators using first-principles methods. Increasing
temperature drives these materials towards the normal state, with similar
contributions from thermal expansion and from electron-phonon coupling. The
band gap changes with temperature reach $0.3$ eV at $600$ K, of similar size to
the changes caused by electron correlation. Our results suggest that
temperature-induced topological phase transitions should be observable near
critical points of other external parameters.


title:
Dissecting the high-z interstellar medium through intensity mapping
  cross-correlations

abstract:
  We explore the detection, with upcoming spectroscopic surveys, of
three-dimensional power spectra of emission line fluctuations produced in
different phases of the Interstellar Medium (ISM) by ionized carbon, ionized
nitrogen and neutral oxygen at redshift z>4. The emission line [CII] from
ionized carbon at 157.7 micron, and multiple emission lines from carbon
monoxide, are the main targets of planned ground-based surveys, and an
important foreground for future space-based surveys like the Primordial
Inflation Explorer (PIXIE). However, the oxygen [OI] (145.5 micron) line, and
the nitrogen [NII] (121.9 micron and 205.2 micron) lines, might be detected in
correlation with [CII] with reasonable signal-to-noise ratio (SNR). These lines
are important coolants of both the neutral and the ionized medium, and probe
multiple phases of the ISM. We compute predictions of the three-dimensional
power spectra for two surveys designed to target the [CII] line, showing that
they have the required sensitivity to detect cross-power spectra with the [OI]
line, and the [NII] lines with sufficient SNR. The importance of
cross-correlating multiple lines is twofold. On the one hand, we will have
multiple probes of the different phases of the ISM, which is key to understand
the interplay between energetic sources, the gas and dust at high redshift.
This kind of studies will be useful for a next-generation space observatory
such as the NASA Far-IR Surveyor. On the other end, emission lines from
external galaxies are an important foreground when measuring spectral
distortions of the Cosmic Microwave Background spectrum with future space-based
experiments like PIXIE; measuring fluctuations in the intensity mapping regime
will help constraining the mean amplitude of these lines, and will allow us to
better handle this important foreground.


title:
Beam combination schemes and technologies for the Planet Formation
  Imager (PFI)

abstract:
  The Planet Formation Imager (PFI) initiative aims at developing the next
generation large scale facility for imaging astronomical optical interferometry
operating in the mid-infrared. Here we report on the progress of the Planet
Formation Imager Technical Working Group on the beam-combination instruments.
We will discuss various available options for the science and fringe-tracker
beam combination instruments, ranging from direct imaging, to non-redundant
fiber arrays, to integrated optics solutions. Besides considering basic
characteristics of the schemes, we will investigate the maturity of the
available technological platforms at near- and mid-infrared wavelengths.


title: Practical Beam Transport for the Planet Formation Imager (PFI)

abstract:
  The Planet Formation Imager (PFI) is a future kilometric-baseline infrared
interferometer to image the complex physical processes of planet formation.
Technologies that could be used to transport starlight to a central
beam-combining laboratory in PFI include free-space propagation in air or
vacuum, and optical fibres. This paper addresses the design and cost issues
associated with free-space propagation in vacuum pipes. The signal losses due
to diffraction over long differential paths are evaluated, and conceptual beam
transport designs employing pupil management to ameliorate these losses are
presented and discussed.


title: The evolution of post-starburst galaxies from z=2 to z= 0.5

abstract:
  We present the evolution in the number density and stellar mass functions of
photometrically selected post-starburst galaxies in the UKIDSS Deep Survey
(UDS), with redshifts of 0.5<z<2 and stellar masses logM>10. We find that this
transitionary species of galaxy is rare at all redshifts, contributing ~5% of
the total population at z~2, to <1% by z~0.5. By comparing the mass functions
of quiescent galaxies to post-starburst galaxies at three cosmic epochs, we
show that rapid quenching of star formation can account for 100% of quiescent
galaxy formation, if the post-starburst spectral features are visible for
~250Myr. The flattening of the low mass end of the quiescent galaxy stellar
mass function seen at z~1 can be entirely explained by the addition of rapidly
quenched galaxies. Only if a significant fraction of post-starburst galaxies
have features that are visible for longer than 250Myr, or they acquire new gas
and return to the star-forming sequence, can there be significant growth of the
red sequence from a slower quenching route. The shape of the mass function of
these transitory post-starburst galaxies resembles that of quiescent galaxies
at z~2, with a preferred stellar mass of logM~10.6, but evolves steadily to
resemble that of star-forming galaxies at z<1. This leads us to propose a dual
origin for post-starburst galaxies: (1) at z>2 they are exclusively massive
galaxies that have formed the bulk of their stars during a rapid assembly
period, followed by complete quenching of further star formation, (2) at z<1
they are caused by the rapid quenching of gas-rich star-forming galaxies,
independent of stellar mass, possibly due to environment and/or gas-rich major
mergers.


title: Stability Aspects of Wormholes in $R^2$ Gravity

abstract:
  We study radial perturbations of a wormhole in $R^2$ gravity to determine
regions of stability. We also investigate massive and massless particle orbits
and tidal forces in this space-time for a radially infalling observer.


title:
Temperature-induced topological phase transitions: promoted vs.
  suppressed non-trivial topology

abstract:
  We determine the topological phase diagram of
BiTl(S$_{1-\delta}$Se$_{\delta}$)$_2$ as a function of doping and temperature
from first-principles calculations. Due to electron\textendash phonon
interaction, the bands are renormalized at finite temperature, allowing for a
transition between the trivial ($Z_2=0$) and non-trivial ($Z_2=1$) topological
phase. We find two distinct regions of the phase diagram with non-trivial
topology. In BiTlS$_2$, the phonons promote the crystal to the topological
phase at high temperature, while in BiTlSe$_2$, the topological phase exists
only at low temperature. This behaviour is explained by the symmetry of the
phonon coupling potential, whereby the even phonon modes (whose potential is
even under inversion) promote the topological phase and the odd phonon modes
promote the trivial phase.


title: Primordial black holes in linear and non-linear regimes

abstract:
  Using the concept of apparent horizon for dynamical black holes, we revisit
the formation of primordial black holes (PBH) in the early universe for both
linear and non-linear regimes. First, we develop the perturbation theory for
spherically symmetric spacetimes to study the formation of spherical PBHs in
linear regime and we fix two gauges. We also introduce a well defined gauge
invariant quantity for the expansion. Using this quantity, we argue that PBHs
do not form in the linear regime. Finally, we study the non-linear regime. We
adopt the spherical collapse picture by taking a closed FRW model in the
radiation dominated era to investigate PBH formation. Taking the initial
condition of the spherical collapse from the linear theory of perturbations, we
allow for both density and velocity perturbations. Our model gives a constraint
on the velocity perturbation. This model also predicts that the apparent
horizon of PBHs forms when $\delta > 3$. Applying the sound horizon constraint,
we have shown the threshold value of density perturbations at horizon re-entry
must be larger than $\delta_{th} > 0.7$ to overcome the pressure gradients.


title: The Halpern-L\"auchli Theorem at a Measurable Cardinal

abstract:
  Several variants of the Halpern-L\"auchli Theorem for trees of uncountable
height are investigated. For $\kappa$ weakly compact, we prove that the various
statements are all equivalent. We show that the strong tree version holds for
one tree on any infinite cardinal. For any finite $d \ge 2$, we prove the
consistency of the Halpern-L\"auchli Theorem on $d$ many $\kappa$-trees at a
measurable cardinal $\kappa$, given the consistency of a $\kappa+d$-strong
cardinal. This follows from a more general consistency result at measurable
$\kappa$, which includes the possibility of infinitely many trees, assuming
partition relations which hold in models of AD.


title:
Post main sequence evolution of icy minor planets: Implications for
  water retention and white dwarf pollution

abstract:
  Most observations of polluted white dwarf atmospheres are consistent with
accretion of water depleted planetary material. Among tens of known cases,
merely two cases involve accretion of objects that contain a considerable mass
fraction of water. The purpose of this study is to investigate the relative
scarcity of these detections. Based on a new and highly detailed model, we
evaluate the retention of water inside icy minor planets during the high
luminosity stellar evolution that follows the main sequence. Our model fully
considers the thermal, physical, and chemical evolution of icy bodies,
following their internal differentiation as well as water depletion, from the
moment of their birth and through all stellar evolution phases preceding the
formation of the white dwarf. We also account for different initial
compositions and formation times. Our results show that previous studies have
either underestimated or overestimated water retention. We also reaffirm that
water can survive in a variety of circumstances and in great quantities, and
therefore other possibilities are discussed in order to explain the infrequency
of water detections. We find that the most likely explanation is that water
does not survive the dissociation of tidally disrupted minor planets, and
instead a direct impact onto the white dwarf is required. We show that this
possibility is statistically plausible, and predict that if this hypothesis is
correct, future observations of extremely water rich atmospheres will involve
only helium dominated DB white dwarfs.


title: Constructing topological models by symmetrization: A PEPS study

abstract:
  Symmetrization of topologically ordered wavefunctions is a powerful method
for constructing new topological models. Here, we study wavefunctions obtained
by symmetrizing quantum double models of a group $G$ in the Projected Entangled
Pair States (PEPS) formalism. We show that symmetrization naturally gives rise
to a larger symmetry group $\tilde G$ which is always non-abelian. We prove
that by symmetrizing on sufficiently large blocks, one can always construct
wavefunctions in the same phase as the double model of $\tilde G$. In order to
understand the effect of symmetrization on smaller patches, we carry out
numerical studies for the toric code model, where we find strong evidence that
symmetrizing on individual spins gives rise to a critical model which is at the
phase transitions of two inequivalent toric codes, obtained by anyon
condensation from the double model of $\tilde G$.


title:
Partial SUSY Breaking for Asymmetric Gepner Models and Non-geometric
  Flux Vacua

abstract:
  Using the method of simple current extensions, asymmetric Gepner models of
Type IIB with N=1 space-time supersymmetry are constructed. The combinatorics
of the massless vector fields suggests that these classical Minkowski string
vacua provide fully backreacted solutions corresponding to N=1 minima of N=2
gauged supergravity. The latter contain abelian gaugings along the axionic
isometries in the hypermultiplet moduli space, and can be considered as Type
IIB flux compactifications on Calabi-Yau manifolds equipped with
(non-)geometric fluxes. For a particular class of asymmetric Gepner models, we
are able to explicitly specify the underlying CICYs and to check necessary
conditions for a GSUGRA interpretation. If this conjecture is correct, there
exists a large class of exactly solvable non-geometric flux compactifications
on CY threefolds.


title: Nuclear Data for Astrophysical Modeling

abstract:
  Nuclear physics has been playing an important role in modern astrophysics and
cosmology. Since the early 1950's it has been successfully applied for the
interpretation and prediction of astrophysical phenomena. Nuclear physics
models helped to explain the observed elemental and isotopic abundances and
star evolution and provided valuable insights on the Big Bang theory. Today,
the variety of elements observed in stellar surfaces, solar system and cosmic
rays, and isotope abundances are calculated and compared with the observed
values. Consequently, the overall success of the modeling critically depends on
the quality of underlying nuclear data that helps to bring physics of macro and
micro scales together. To broaden the scope of traditional nuclear astrophysics
activities and produce additional complementary information, I will investigate
applicability of the U.S. Nuclear Data Program (USNDP) databases for
astrophysical applications. EXFOR (Experimental Nuclear Reaction Data) and ENDF
(Evaluated Nuclear Data File) libraries have large astrophysics potential; the
former library contains experimental data sets while the latter library
includes evaluated neutron cross sections. ENSDF (Evaluated Nuclear Structure
Data File) database is a primary depository of nuclear structure and decay
rates information. The decay rates are essential in stellar nucleosynthesis
calculations, and these rates are evaluated using nuclear structure codes. The
structure evaluation codes are pure mathematical procedures that can be applied
to diverse data samples. A brief review of astrophysical nuclear data needs has
been presented. Several opportunities and the corresponding computer tools have
been identified. Further work will include extensive analysis of nuclear
databases and computer procedures for astrophysical calculations.


title: Topological Sigma Models On Supermanifolds

abstract:
  This paper concerns constructing topological sigma models governing maps from
semirigid super Riemann surfaces to general target supermanifolds. We define
both the A model and B model in this general setup by defining suitable BRST
operators and physical observables. Using supersymmetric localization, we
express correlation functions in these theories as integrals over suitable
supermanifolds. In the case of the A model, we obtain an integral over the
supermoduli space of "superinstantons". The language of supergeometry is used
extensively throughout this paper.


title: Computing the Feasible Spaces of Optimal Power Flow Problems

abstract:
  The solution to an optimal power flow (OPF) problem provides a minimum cost
operating point for an electric power system. The performance of OPF solution
techniques strongly depends on the problem's feasible space. This paper
presents an algorithm for provably computing the entire feasible spaces of
small OPF problems to within a specified discretization tolerance.
Specifically, the feasible space is computed by discretizing certain of the OPF
problem's inequality constraints to obtain a set of power flow equations. All
solutions to the power flow equations at each discretization point are obtained
using the Numerical Polynomial Homotopy Continuation (NPHC) algorithm. To
improve computational tractability, "bound tightening" and "grid pruning"
algorithms use convex relaxations to eliminate the consideration of
discretization points for which the power flow equations are provably
infeasible. The proposed algorithm is used to generate the feasible spaces of
two small test cases.


title: On Spin Calogero-Moser system at infinity

abstract:
  We present a construction of a new integrable model as an infinite limit of
Calogero models of N particles with spin. It is implemented in the
multicomponent Fock space. Explicit formulas for Dunkl operators, the Yangian
generators in the multicomponent Fock space are presented. The classical limit
of the system is examined.


title:
The Bridgeman-Kahn identity for hyperbolic manifolds with cusped
  boundary

abstract:
  In this note, we extend the Bridgeman-Kahn identity to all finite-volume
orientable hyperbolic $n$-manifolds with totally geodesic boundary. In the
compact case, Bridgeman and Kahn are able to express the manifold's volume as
the sum of a function over only the orthospectrum. For manifolds with
non-compact boundary, our extension adds terms corresponding to intrinsic
invariants of boundary cusps.


abstract:
  The existence of solutions to Cauchy type problems of linear
Riemann-Liouville fractional differential equations with variable coefficients
is considered in a space of integrable functions. First, we consider the
existence and uniqueness of solution for a Cauchy type problem with special
initial conditions in the space of integrable functions. Then we provide an
example of the problem that has no solution in the space of integrable
functions. We give a solving method and a representation of solutions for the
Cauchy type problem. Last we give some examples.


title:
Compact stars with strongly coupled quark matter in a strong magnetic
  field

abstract:
  Some time ago we have derived from the QCD Lagrangian an equation of state
(EOS) for the cold quark matter, which can be considered an improved version of
the MIT bag model EOS. Compared to the latter, our equation of state reaches
higher values of the pressure at comparable baryon densities. This feature is
due to perturbative corrections and also to non-perturbative effects. Later we
applied this EOS to the study of compact stars, discussing the absolute
stability of quark matter and computing the mass-radius relation for self-bound
(strange) stars. We found maximum masses of the sequences with more than two
solar masses, in agreement with the recent experimental observations. In the
present work we include the magnetic field in the equation of state and study
how it changes the stability conditions and the mass-radius curves.


title:
Pareto-efficient biological pest control enable high efficacy at small
  costs

abstract:
  Biological pest control is increasingly used in agriculture as a an
alternative to traditional chemical pest control. In many cases, this involves
a one-off or periodic release of naturally occurring and/or genetically
modified enemies such as predators, parasitoids, or pathogens. As the
interaction between these enemies and the pest is complex and the production of
natural enemies potentially expensive, it is not surprising that both the
efficacy and economic viability of biological pest control are debated. Here,
we investigate the performance of very simple control strategies. In
particular, we show how Pareto-efficient one-off or periodic release
strategies, that optimally trade off between efficacy and economic viability,
can be devised and used to enable high efficacy at small economic costs. We
demonstrate our method on a pest-pathogen-crop model with a tunable immigration
rate of pests. By analyzing this model, we demonstrate that simple
Pareto-efficient one-off and periodic release strategies are efficacious and
simultaneously have profits that are close to the theoretical maximum obtained
by strategies optimizing only the profit. When the immigration rate of pests is
low to intermediate, one-off control strategies are sufficient, and when the
immigration of pests is high, periodic release strategies are preferable. The
methods presented here can be extended to more complex scenarios and be used to
identify promising biological pest control strategies in many circumstances.


title:
Response of a tungsten powder target to an incident high energy proton
  beam

abstract:
  The experiment described in this paper is the first study of the response of
a static tungsten powder sample to an impinging high energy proton beam pulse.
The experiment was carried out at the HiRadMat facility at CERN. Observations
include high speed videos of a proton beam induced perturbation of the powder
sample as well as data from a laser Doppler vibrometer measuring the
oscillations of the powder container. A comparison with a previous analogous
experiment which studied a proton beam interaction with mercury is made


title:
Influence of the multiband sign changing superconductivity on the vortex
  cores and on vortex pinning in the new stoichiometric high Tc CaKFe4As4

abstract:
  We study the superconducting density of states and vortex lattice of single
crystals of CaKFe$_4$As$_4$ using a scanning tunneling microscope (STM). This
material has a critical temperature of $T_c= 35\,$ K, which is one of the
highest among stoichiometric iron based superconductors (FeBSC) and is
comparable to $T_c$ found near optimal doping in other FeBSC. Using
quasi-particle interference we identify the hole sheets around the zone center
and find that two superconducting gaps open in these sheets. The scattering
centers are small defects that can be localized in the surface topography and
just produce quasiparticle interference, without suppressing the
superconducting order parameter. This shows that sign inversion is not within
hole bands, but between hole and the electron bands. Vortex core bound states
show electron-hole asymmetric bound states due to proximity of the top of one
of the hole bands to the Fermi level $E_F$. This places CaKFe$_4$As$_4$ in a
similar situation as FeSe or related materials, with a superconducting gap
$\Delta$ just a few times smaller than $E_F$. On the other hand, we also
identify locations showing strong suppression of the superconducting order
parameter. Their size is of order of the vortex core size and vortices are
pinned at these locations, leading to a disordered vortex lattice.


title: Near-Field Perturbation Effect on Constellation Error in Beam-Space MIMO

abstract:
  Beam-space MIMO has recently been proposed as a promising solution to enable
transmitting multiple data streams using a single RF chain and a single
pattern-reconfigurable antenna. Since in a beam-space MIMO system radiation
pattern of the transmit antenna is exploited as extra dimension for encoding
information, near-field interaction of the transmit antenna with its
surrounding objects affects spatial multiplexing performance of the system.
Through numerical simulations in the previous work, it has been concluded that
under BPSK signaling beam-space MIMO is not more vulnerable to near-field
coupling than its conventional counterpart. In this work, we extend the study
to the case of higher-order modulation schemes, where the presence of external
perturbation also affects the data constellation points transmitted by a
beam-space MIMO antenna. To this aim, the error vector magnitude of the
transmitted signal is evaluated when placing a QPSK beam-space MIMO antenna in
close proximity to a hand model of the user. The obtained results emphasize the
importance of reconsidering the decoding approach for beam-space MIMO systems
in practical applications.


title: Configuring Random Graph Models with Fixed Degree Sequences

abstract:
  Random graph null models have found widespread application in diverse
research communities analyzing network datasets, including social, information,
and economic networks, as well as food webs, protein-protein interactions, and
neuronal networks. The most popular family of random graph null models, called
configuration models, are defined as uniform distributions over a space of
graphs with a fixed degree sequence. Commonly, properties of an empirical
network are compared to properties of an ensemble of graphs from a
configuration model in order to quantify whether empirical network properties
are meaningful or whether they are instead a common consequence of the
particular degree sequence. In this work we study the subtle but important
decisions underlying the specification of a configuration model, and
investigate the role these choices play in graph sampling procedures and a
suite of applications. We place particular emphasis on the importance of
specifying the appropriate graph labeling (stub-labeled or vertex-labeled)
under which to consider a null model, a choice that closely connects the study
of random graphs to the study of random contingency tables. We show that the
choice of graph labeling is inconsequential for studies of simple graphs, but
can have a significant impact on analyses of multigraphs or graphs with
self-loops. The importance of these choices is demonstrated through a series of
three vignettes, analyzing network datasets under many different configuration
models and observing substantial differences in study conclusions under
different models. We argue that in each case, only one of the possible
configuration models is appropriate. While our work focuses on undirected
static networks, it aims to guide the study of directed networks, dynamic
networks, and all other network contexts that are suitably studied through the
lens of random graph null models.

categories: stat.ME cs.SI physics.data-an physics.soc-ph q-bio.QM


title:
MOSFIRE Spectroscopy of Quiescent Galaxies at 1.5 < z < 2.5. I -
  Evolution of Structural and Dynamical Properties

abstract:
  We present deep near-infrared spectra for a sample of 24 quiescent galaxies
in the redshift range 1.5 < z < 2.5 obtained with the MOSFIRE spectrograph at
the W. M. Keck Observatory. In conjunction with a similar dataset we obtained
in the range 1 < z < 1.5 with the LRIS spectrograph, we analyze the kinematic
and structural properties for 80 quiescent galaxies, the largest
homogeneously-selected sample to date spanning 3 Gyr of early cosmic history.
Analysis of our Keck spectra together with measurements derived from associated
HST images reveals increasingly larger stellar velocity dispersions and smaller
sizes to redshifts beyond z~2. By classifying our sample according to Sersic
indices, we find that among disk-like systems the flatter ones show a higher
dynamical to stellar mass ratio compared to their rounder counterparts which we
interpret as evidence for a significant contribution of rotational motion. For
this subset of disk-like systems, we estimate that V/sigma, the ratio of the
circular velocity to the intrinsic velocity dispersion, is a factor of two
larger than for present-day disky quiescent galaxies. We use the velocity
dispersion measurements also to explore the redshift evolution of the dynamical
to stellar mass ratio, and to measure for the first time the physical size
growth rate of individual systems over two distinct redshift ranges, finding a
faster evolution at earlier times. We discuss the physical origin of this
time-dependent growth in size in the context of the associated reduction of the
systematic rotation.


title:
Server assisted distributed cooperative localization over unreliable
  communication links

abstract:
  This paper considers the problem of cooperative localization (CL) using
inter-robot measurements for a group of networked robots with limited on-board
resources. We propose a novel recursive algorithm in which each robot localizes
itself in a global coordinate frame by local dead reckoning, and
opportunistically corrects its pose estimate whenever it receives a relative
measurement update message from a server. The computation and storage cost per
robot in terms of the size of the team is of order O(1), and the robots are
only required to transmit information when they are involved in a relative
measurement. The server also only needs to compute and transmit update messages
when it receives an inter-robot measurement. We show that under perfect
communication, our algorithm is an alternative but exact implementation of a
joint CL for the entire team via Extended Kalman Filter (EKF). The perfect
communication however is not a hard requirement. In fact, we show that our
algorithm is intrinsically robust with respect to communication failures, with
formal guarantees that the updated estimates of the robots receiving the update
message are of minimum variance in a first-order approximate sense at that
given timestep. We demonstrate the performance of the algorithm in simulation
and experiments.


title: Cohomology for spatial super-product systems

abstract:
  We introduce a cohomology theory for spatial super- product systems and
compute the $2-$cocycles for some basic examples called as Clifford
super-product systems, thereby distinguish them up to isomorphism. This
consequently proves that a family of $E_0-$semigroups on type III factors,
which we call as CAR flows, are non-cocycle-conjugate for different ranks.
Similar results follows for the even CAR flows as well. We also compute the
automorphsim group of the Clifford super-product systems.


title:
Attention Tree: Learning Hierarchies of Visual Features for Large-Scale
  Image Recognition

abstract:
  One of the key challenges in machine learning is to design a computationally
efficient multi-class classifier while maintaining the output accuracy and
performance. In this paper, we present a tree-based classifier: Attention Tree
(ATree) for large-scale image classification that uses recursive Adaboost
training to construct a visual attention hierarchy. The proposed attention
model is inspired from the biological 'selective tuning mechanism for cortical
visual processing'. We exploit the inherent feature similarity across images in
datasets to identify the input variability and use recursive optimization
procedure, to determine data partitioning at each node, thereby, learning the
attention hierarchy. A set of binary classifiers is organized on top of the
learnt hierarchy to minimize the overall test-time complexity. The attention
model maximizes the margins for the binary classifiers for optimal decision
boundary modelling, leading to better performance at minimal complexity. The
proposed framework has been evaluated on both Caltech-256 and SUN datasets and
achieves accuracy improvement over state-of-the-art tree-based methods at
significantly lower computational cost.


title:
Structured prediction models for RNN based sequence labeling in clinical
  text

abstract:
  Sequence labeling is a widely used method for named entity recognition and
information extraction from unstructured natural language data. In clinical
domain one major application of sequence labeling involves extraction of
medical entities such as medication, indication, and side-effects from
Electronic Health Record narratives. Sequence labeling in this domain, presents
its own set of challenges and objectives. In this work we experimented with
various CRF based structured learning models with Recurrent Neural Networks. We
extend the previously studied LSTM-CRF models with explicit modeling of
pairwise potentials. We also propose an approximate version of skip-chain CRF
inference with RNN potentials. We use these methodologies for structured
prediction in order to improve the exact phrase detection of various medical
entities.


title:
Skipping Selected Steps of DWT Computation in Lossless JPEG 2000 for
  Improved Bitrates

abstract:
  In order to improve bitrates of lossless JPEG 2000, we propose to modify the
discrete wavelet transform (DWT) by skipping selected steps of its computation.
We employ a heuristic to construct the skipped steps DWT (SS-DWT) in an
image-adaptive way and define fixed SS-DWT variants. For a large and diverse
set of images, we find that SS-DWT significantly improves bitrates of
non-photographic images. From a practical standpoint, the most interesting
results are obtained by applying entropy estimation of coding effects for
selecting among the fixed SS-DWT variants. This way we get the compression
scheme that, as opposed to the general SS-DWT case, is compliant with the JPEG
2000 part 2 standard. It provides average bitrate improvement of roughly 5% for
the entire test-set, whereas the overall compression time becomes only 3%
greater than that of the unmodified JPEG 2000. Bitrates of photographic and
non-photographic images are improved by roughly 0.5% and 14%, respectively. At
a significantly increased cost of exploiting a heuristic, selecting the steps
to be skipped based on the actual bitrate instead of an estimated one, and by
applying reversible denoising and lifting steps to SS-DWT, we have attained
greater bitrate improvements of up to about 17.5% for non-photographic images.


title:
Entanglement and thermodynamics after a quantum quench in integrable
  systems

abstract:
  Entanglement and entropy are key concepts standing at the foundations of
quantum and statistical mechanics, respectively. In the last decade the study
of quantum quenches revealed that these two concepts are intricately
intertwined. Although the unitary time evolution ensuing from a pure initial
state maintains the system globally at zero entropy, at long time after the
quench local properties are captured by an appropriate statistical ensemble
with non zero thermodynamic entropy, which can be interpreted as the
entanglement accumulated during the dynamics. Therefore, understanding the
post-quench entanglement evolution unveils how thermodynamics emerges in
isolated quantum systems. An exact computation of the entanglement dynamics has
been provided only for non-interacting systems, and it was believed to be
unfeasible for genuinely interacting models. Conversely, here we show that the
standard quasiparticle picture of the entanglement evolution, complemented with
integrability-based knowledge of the asymptotic state, leads to a complete
analytical understanding of the entanglement dynamics in the space-time scaling
limit. Our framework requires only knowledge about the steady state, and the
velocities of the low-lying excitations around it. We provide a thorough check
of our result focusing on the spin-1/2 Heisenberg XXZ chain, and considering
quenches from several initial states. We compare our results with numerical
simulations using both tDMRG and iTEBD, finding always perfect agreement.

categories: cond-mat.str-el cond-mat.quant-gas cond-mat.stat-mech math-ph math.MP quant-ph


title:
Closed-form approximations for the performance upper bound of
  inhomogeneous quadratic tests

abstract:
  This paper focuses on inhomogeneous quadratic tests, which involve the sum of
a dependent non-central chi-square with a Gaussian random variable.
Unfortunately, no closed-form expression is available for the statistical
distribution of the resulting random variable, thus hindering the analytical
characterization of these tests in terms of probability of detection and
probability of false alarm. In order to circumvent this limitation, two
closed-form approximations are proposed in this work based on results from
Edgeworth series expansions and Extreme Value Theory (EVT). The use of these
approximations is shown through a specific case of study in the context of
integrity transient detection for Global Navigation Satellite Systems (GNSS).
Numerical results are provided to assess the goodness of the proposed
approximations, and to highlight their interest in real life applications.


title:
The classical harmonic chain: solution via Laplace transforms and
  continued fractions

abstract:
  The harmonic chain is a classical many-particle system which can be solved
exactly for arbitrary number of particles (at least in simple cases, such as
equal masses and spring constants). A nice feature of the harmonic chain is
that the final result for the displacements of the individual particles can be
easily understood -- therefore, this example fits well into a course of
classical mechanics for undergraduates. Here we show how to calculate the
displacements by solving equations of motion for the Laplace transforms
$\mathcal{L}\left\{q_n\right\}(s)$ of the displacements $q_n(t)$. This leads to
a continued fraction representation of the Laplace transforms which can be
evaluated analytically. The inverse Laplace transform of
$\mathcal{L}\left\{q_n\right\}(s)$ finally gives the displacements which
generically have the form of Bessel functions. We also comment on the
similarities between this approach and the Green function method for quantum
many-particle systems.


title: On rank of the join of two subgroups in a free group

abstract:
  Let $H, K$ be two finitely generated subgroups of a free group, let $\langle
H, K \rangle$ denote the subgroup generated by $H, K$, called the join of $H,
K$, and let neither of $H$, $K$ have finite index in $\langle H, K \rangle$. We
prove the existence of an epimorphism $\zeta : \langle H, K \rangle \to F_2$,
where $F_2$ is a free group of rank 2, such that the restriction of $\zeta$ on
both $H$ and $K$ is injective and the restriction $\zeta_0 : H \cap K \to \zeta
(H) \cap \zeta (K) $ of $\zeta$ on $H \cap K $ to $\zeta (H) \cap \zeta (K)$ is
surjective. This is obtained as a corollary of an analogous result on rank of
the generalized join of two finitely generated subgroups in a free group.