title: Probability current and thermodynamics of open quantum systems

abstract:
  This paper explores the generalization of the concept of a "probability
current", familiar from wave-function quantum mechanics, to quantum systems
with finite-dimensional Hilbert spaces. The generalized definition applies both
to isolated systems evolving via the Schr\"odinger equation and to more general
open systems obeying the Lindblad master equation. We establish several
properties of the probability current and explore its relation to thermodynamic
heat and work.


title:
Electron-acoustic-phonon interaction in core/shell Ge/Si and Si/Ge
  nanowires

abstract:
  General expressions for the electron- and hole-acoustical-phonon deformation
potential Hamiltonian (H_{E-DP}) are derived for the case of Ge/Si and Si/Ge
core/shell nanowire structures (NWs) with circular cross section. Based on the
short-range elastic continuum approach and on derived analytical results, the
spatial confined effects on the vector phonon displacement, the phonon
dispersion relation and the electron- and hole-phonon scattering amplitudes are
analyzed. It is shown that the acoustical vector displacement, phonon
frequencies and H_{E-DP} present mixed torsional, axial, and radial components
depending on the angular momentum quantum number and phonon wavector under
consideration. The treatment shows that bulk group velocities of the
constituent materials are renormalized due to the spatial confinement and
intrinsic strain at the interface. The role of insulating shell on the phonon
dispersion and electron-phonon coupling in Ge/Si and Si/Ge NWs are discussed.


title: Two-dimensional superconductivity in a bulk single-crystal

abstract:
  Both Nb$_3$Pd$_x$Se$_7$ and Ta$_4$Pd$_3$Te$_{16}$ crystallize in a monoclinic
point group while exhibiting superconducting transition temperatures as high as
$T_c\sim 3.5$ and $\sim 4.7 $ K, respectively. Disorder was claimed to lead to
the extremely large upper critical fields ($H_{c2}$) observed in related
compounds. Despite the presence of disorder and heavier elements, $H_{c2}$s in
Ta$_4$Pd$_3$Te$_{16}$ are found to be considerably smaller than those of
Nb$_3$Pd$_x$Se$_7$ while displaying an anomalous, non-saturating linear
dependence on temperature $T$ for fields along all three crystallographic axes.
In contrast, crystals of the latter compound displaying the highest $T_c$s
display $H_{c2}\propto (1-T/T_c)^{1/2}$, which in monolayers of transition
metal dichalcogenides is claimed to be evidence for an Ising paired
superconducting state resulting from strong spin-orbit coupling. This anomalous
$T$-dependence indicates that the superconducting state of Nb$_3$Pd$_x$Se$_7$
is quasi-two-dimensional in nature. This is further supported by a nearly
divergent anisotropy in upper-critical fields, i.e. $\gamma=
H_{c2}^{b}/H_{c2}^{a^{\prime}}$, upon approaching $T_c$. Hence, in
Nb$_3$Pd$_x$Se$_7$ the increase of $T_c$ correlates with a marked reduction in
electronic dimensionality as observed, for example, in intercalated FeSe. For
the Nb compound, Density functional theory (DFT) calculations indicate that an
increase in the external field produces an anisotropic orbital response, with
especially strong polarization at the Pd sites when the field is perpendicular
to their square planar environment. Therefore, DFT suggests the field-induced
pinning of the spin to the lattice as a possible mechanism for decoupling the
superconducting planes. Overall, our observations represent further evidence
for unconventional superconductivity in the Pd chalcogenides.


title:
Structure function and fractal dissipation for an intermittent inviscid
  dyadic model

abstract:
  We study a generalization of the original tree-indexed dyadic model by Katz
and Pavlovi\'c for the turbulent energy cascade of three-dimensional Euler
equation. We allow the coefficients to vary with some restrictions, thus giving
the model a realistic spatial intermittency. By introducing a forcing term on
the first component, the fixed point of the dynamics is well defined and some
explicit computations allow to prove the rich multifractal structure of the
solution. In particular the exponent of the structure function is concave in
accordance with other theoretical and experimental models. Moreover anomalous
energy dissipation happens in a fractal set of dimension strictly less than 3.


title:
Matrix Factorization at Scale: a Comparison of Scientific Data Analytics
  in Spark and C+MPI Using Three Case Studies

abstract:
  We explore the trade-offs of performing linear algebra using Apache Spark,
compared to traditional C and MPI implementations on HPC platforms. Spark is
designed for data analytics on cluster computing platforms with access to local
disks and is optimized for data-parallel tasks. We examine three widely-used
and important matrix factorizations: NMF (for physical plausability), PCA (for
its ubiquity) and CX (for data interpretability). We apply these methods to
TB-sized problems in particle physics, climate modeling and bioimaging. The
data matrices are tall-and-skinny which enable the algorithms to map
conveniently into Spark's data-parallel model. We perform scaling experiments
on up to 1600 Cray XC40 nodes, describe the sources of slowdowns, and provide
tuning guidance to obtain high performance.


title:
Probing the core and shell contributions to exchange bias in
  Co/Co$_3$O$_4$ nanoparticles of controlled size

abstract:
  Coupling at the interface of core/shell magnetic nanoparticles is known to be
responsible for the exchange bias (EB) and the relative sizes of core and shell
components are supposed to influence the associated phenomenology. In this
work, we have prepared core/shell structured nanoparticles with the total
averaged diameter around $\sim$ 27 nm and a wide range of shell thicknesses
through the controlled oxidation of Co nanoparticles well dispersed in an
amorphous silica host. Structural characterizations give compelling evidence of
the formation of Co$_3$O$_4$ crystallite phase at the shells surrounding the Co
core. Field cooled hysteresis loops display nonmonotonous dependence of the
exchange bias $H_E$ and coercive $H_C$ fields, that become maximum for a sample
with an intermediate shell thickness, at which lattice strain is also maximum
for both the phases. Results of our atomistic Monte Carlo simulations of the
particles with the same size and compositions as in experiments are in
agreement with the experimental observations and have allowed us to identify a
change in the contribution of the interfacial surface spins to the
magnetization reversal giving rise to the maximum in $H_E$ and $H_C$.


title: Can mobile usage predict illiteracy in a developing country?

abstract:
  The present study provides the first evidence that illiteracy can be reliably
predicted from standard mobile phone logs. By deriving a broad set of mobile
phone indicators reflecting users financial, social and mobility patterns we
show how supervised machine learning can be used to predict individual
illiteracy in an Asian developing country, externally validated against a
large-scale survey. On average the model performs 10 times better than random
guessing with a 70% accuracy. Further we show how individual illiteracy can be
aggregated and mapped geographically at cell tower resolution. Geographical
mapping of illiteracy is crucial to know where the illiterate people are, and
where to put in resources. In underdeveloped countries such mappings are often
based on out-dated household surveys with low spatial and temporal resolution.
One in five people worldwide struggle with illiteracy, and it is estimated that
illiteracy costs the global economy more than 1 trillion dollars each year.
These results potentially enable costeffective, questionnaire-free
investigation of illiteracy-related questions on an unprecedented scale


title: The Fisher-KPP problem with doubly nonlinear "fast" diffusion

abstract:
  The famous Fisher-KPP reaction diffusion model combines linear diffusion with
the typical Fisher-KPP reaction term, and appears in a number of relevant
applications. It is remarkable as a mathematical model since, in the case of
linear diffusion, it possesses a family of travelling waves that describe the
asymptotic behaviour of a wide class solutions $0\leq u(x,t)\leq 1$ of the
problem posed in the real line. The existence of propagation wave with finite
speed has been confirmed in the cases of "slow" and "pseudo-linear" doubly
nonlinear diffusion too, see arXiv:1601.05718. We investigate here the
corresponding theory with "fast" doubly nonlinear diffusion and we find that
general solutions show a non-TW asymptotic behaviour, and exponential
propagation in space for large times. Finally, we prove precise bounds for the
level sets of general solutions, even when we work in with spacial dimension $N
\geq 1$. In particular, we show that location of the level sets is
approximately linear for large times, when we take spatial logarithmic scale,
finding a strong departure from the linear case, in which appears the famous
Bramson logarithmic correction.


title:
Ion-Acoustic Envelope Modes in a Degenerate Relativistic Electron-Ion
  Plasma

abstract:
  A self-consistent relativistic two-fluid model is proposed for
one-dimensional electron-ion plasma dynamics. A multiple scales perturbation
technique is employed, leading to an evolution equation for the wave envelope,
in the form of a nonlinear Schr\"odinger type equation (NLSE). The inclusion of
relativistic effects is shown to introduce density-dependent factors, not
present in the non-relativistic case - in the conditions for modulational
instability. The role of relativistic effects on the linear dispersion laws and
on envelope soliton solutions of the NLSE is discussed.


title:
Electrical conductivity of hadronic matter from different possible
  mesonic and baryonic thermal fluctuations

abstract:
  Electromagnetic current-current correlators in pionic and nucleonic medium
have been evaluated in the static limit to obtain electrical conductivities for
pion and nucleon components respectively, where former decreases and latter one
increases with the variation of temperature $T$ and baryon chemical potential
$\mu_N$. Therefore, total electrical conductivity of pion and nucleon system
exhibits a valley structure in the $T$-$\mu_N$ plane. To get non-divergent and
finite values of correlators, finite thermal widths of medium constituents,
pion and nucleon have been considered, where these thermal widths have been
determined from the in-medium scattering probabilities of pion and nucleon with
other mesonic and baryonic resonances, based on effective hadronic model. At
$\mu_N=0$, the results of present work are more or less agrees with the results
of earlier works and its finite $\mu_N$ extension show a decreasing nature of
electrical conductivity for hadronic medium during spanning from freeze out
line to quark-hadron transition line in $T$-$\mu_N$ plane.


title: Algorand

abstract:
  A public ledger is a tamperproof sequence of data that can be read and
augmented by everyone. Public ledgers have innumerable and compelling uses.
They can secure, in plain sight, all kinds of transactions ---such as titles,
sales, and payments--- in the exact order in which they occur. Public ledgers
not only curb corruption, but also enable very sophisticated applications
---such as cryptocurrencies and smart contracts. They stand to revolutionize
the way a democratic society operates. As currently implemented, however, they
scale poorly and cannot achieve their potential.
  Algorand is a truly democratic and efficient way to implement a public
ledger. Unlike prior implementations based on proof of work, it requires a
negligible amount of computation, and generates a transaction history that will
not "fork" with overwhelmingly high probability.
  Algorand is based on (a novel and super fast) message-passing Byzantine
agreement.
  For concreteness, we shall describe Algorand only as a money platform.


title: An Isomorphism Extension Theorem for Landau-Ginzburg B-Models

abstract:
  Landau-Ginzburg mirror symmetry studies isomorphisms between A- and B-models,
which are graded Frobenius algebras that are constructed using a weighted
homogeneous polynomial $W$ and a related group of symmetries $G$ of $W$. It is
known that given two polynomials $W_{1}$, $W_{2}$ with the same weights and
same group $G$, the corresponding A-models built with ($W_{1}$,$G$) and
($W_{2}$,$G$) are isomorphic. Though the same result cannot hold in full
generality for B-models, which correspond to orbifolded Milnor rings, we
provide a partial analogue. In particular, we exhibit conditions where
isomorphisms between unorbifolded B-models (or Milnor rings) can extend to
isomorphisms between their corresponding orbifolded B-models (or orbifolded
Milnor rings).


title:
On the sharpness of one inequality of different metrics for algebraic
  polynomials

abstract:
  We prove that the previously established inequality of different metrics for
algebraic polynomials is sharp in the sense of order.


title: Efficient characteristic refinements for finite groups

abstract:
  Filters were introduced by J.B. Wilson in 2013 to generalize work of Lazard
with associated graded Lie rings. It holds promise in improving isomorphism
tests, but the formulas introduced then were impractical for computation. Here,
we provide an efficient algorithm for these formulas, and we demonstrate their
usefulness on several examples of $p$-groups.


title:
Distortion Bounds for Transmitting Correlated Sources with Common Part
  over MAC

abstract:
  This paper investigates the joint source-channel coding problem of sending
two correlated memoryless sources with common part over a memoryless multiple
access channel (MAC). An inner bound and two outer bounds on the achievable
distortion region are derived. In particular, they respectively recover the
existing bounds for several special cases, such as communication without common
part, lossless communication, and noiseless communication. When specialized to
quadratic Gaussian communication case, transmitting Gaussian sources with
Gaussian common part over Gaussian MAC, the inner bound and outer bound are
used to generate two new bounds. Numerical result shows that common part
improves the distortion of such distributed source-channel coding problem.


title:
Resource Allocation in a MAC with and without security via Game
  Theoretic Learning

abstract:
  In this paper a $K$-user fading multiple access channel with and without
security constraints is studied. First we consider a F-MAC without the security
constraints. Under the assumption of individual CSI of users, we propose the
problem of power allocation as a stochastic game when the receiver sends an ACK
or a NACK depending on whether it was able to decode the message or not. We
have used Multiplicative weight no-regret algorithm to obtain a Coarse
Correlated Equilibrium (CCE). Then we consider the case when the users can
decode ACK/NACK of each other. In this scenario we provide an algorithm to
maximize the weighted sum-utility of all the users and obtain a Pareto optimal
point. PP is socially optimal but may be unfair to individual users. Next we
consider the case where the users can cooperate with each other so as to
disagree with the policy which will be unfair to individual user. We then
obtain a Nash bargaining solution, which in addition to being Pareto optimal,
is also fair to each user.
  Next we study a $K$-user fading multiple access wiretap Channel with CSI of
Eve available to the users. We use the previous algorithms to obtain a CCE, PP
and a NBS.
  Next we consider the case where each user does not know the CSI of Eve but
only its distribution. In that case we use secrecy outage as the criterion for
the receiver to send an ACK or a NACK. Here also we use the previous algorithms
to obtain a CCE, PP or a NBS. Finally we show that our algorithms can be
extended to the case where a user can transmit at different rates. At the end
we provide a few examples to compute different solutions and compare them under
different CSI scenarios.


title:
A low-temperature external cavity diode laser for broad wavelength
  tuning

abstract:
  We report on the design and characterization of a low-temperature external
cavity diode laser (ECDL) system for broad wavelength tuning. The performance
achieved with multiple diode models addresses the scarcity of commercial red
laser diodes below 633 nm, which is a wavelength range relevant to spectroscopy
of many molecules and ions. Using a combination of multiple-stage
thermoelectric cooling and water cooling, the operating temperature of a laser
diode is lowered to -64{\deg}C, more than 85{\deg}C below the ambient
temperature. The laser system integrates temperature and diffraction grating
feedback tunability for coarse and fine wavelength adjustments, respectively.
For two different diode models, single-mode operation was achieved with 38 mW
output power at 616.8 nm and 69 mW at 622.6 nm, more than 15 nm below their
ambient temperature free-running wavelengths. The ECDL design can be used for
diodes of any available wavelength, allowing individual diodes to be tuned
continuously over tens of nanometers and extending the wavelength coverage of
commercial laser diodes.


title:
Visible and hidden sectors in a model with Maxwell and Chern-Simons
  gauge dynamics

abstract:
  We study a $U(1) \times U(1)$ gauge theory discussing its vortex solutions
and supersymmetric extension. In our set-upon the dynamics of one of two
Abelian gauge fields is governed by a Maxwell term, the other by a Chern-Simons
term. The two sectors via a BF gauge field mixing and a Higgs portal term that
connects the two complex scalars. We also consider the supersymmetric version
of this system which allows to find for the bosonic sector BPS equations in
which an additional real scalar field enters into play. We study numerically
the field equations finding vortex solutions with both magnetic flux and
electric charge.


title:
Rate of convergence of attractors for semilinear singularly perturbed
  problems: parabolic equations with large diffusion

abstract:
  We exhibit a singularly perturbed parabolic problems for which the asymptotic
behavior can be described by an one-dimensional ordinary differential equation.
We estimate the continuity of attractors in the Hausdorff metric by rate of
convergence of resolvent operator.


title:
Non-classical correlations between a C-band telecom photon and a stored
  spin-wave

abstract:
  Future ground-based quantum information networks will likely use single
photons transmitted through optical fibers to entangle individual network
nodes. To extend communication distances and overcome limitations due to photon
absorption in fibers the concept of quantum repeaters has been proposed. For
that purpose, it is required to achieve quantum correlations between the
material nodes and photons at telecom wavelengths which can be sent over long
distances in optical fibers. Here we demonstrate non-classical correlation
between a frequency converted telecom C-band photon and a spin-wave stored in
an atomic ensemble quantum memory. The photons emitted from the ensemble and
heralding the spin-waves are converted from 780 nm to 1552 nm by means of an
all-solid-state integrated waveguide non-linear device. We show ultra-low noise
operation of the device enabling a high signal to noise ratio of the converted
single photon, leading to a high spin-wave heralding efficiency. The presented
work is an enabling step towards the practical entanglement of remote quantum
memories and the entanglement of quantum systems operating at different
wavelengths.


title: On the Tracy-Widom$_\beta$ Distribution for $\beta=6$

abstract:
  We study the Tracy-Widom distribution function for Dyson's $\beta$-ensemble
with $\beta = 6$. The starting point of our analysis is the recent work of I.
Rumanov where he produces a Lax-pair representation for the Bloemendal-Vir\'ag
equation. The latter is a linear PDE which describes the Tracy-Widom functions
corresponding to general values of $\beta$. Using his Lax pair, Rumanov derives
an explicit formula for the Tracy-Widom $\beta=6$ function in terms of the
second Painlev\'e transcendent and the solution of an auxiliary ODE. Rumanov
also shows that this formula allows him to derive formally the asymptotic
expansion of the Tracy-Widom function. Our goal is to make Rumanov's approach
and hence the asymptotic analysis it provides rigorous. In this paper, the
first one in a sequel, we show that Rumanov's Lax-pair can be interpreted as a
certain gauge transformation of the standard Lax pair for the second Painlev\'e
equation. This gauge transformation though contains functional parameters which
are defined via some auxiliary nonlinear ODE which is equivalent to the
auxiliary ODE of Rumanov's formula. The gauge-interpretation of Rumanov's
Lax-pair allows us to highlight the steps of the original Rumanov's method
which needs rigorous justifications in order to make the method complete. We
provide a rigorous justification of one of these steps. Namely, we prove that
the Painlev\'e function involved in Rumanov's formula is indeed, as it has been
suggested by Rumanov, the Hastings-McLeod solution of the second Painlev\'e
equation. The key issue which we also discuss and which is still open is the
question of integrability of the auxiliary ODE in Rumanov's formula. We note
that this question is crucial for the rigorous asymptotic analysis of the
Tracy-Widom function.


title: Transverse forces on vortices in superfluids in a periodic potential

abstract:
  The paper analyzes the transverse forces (the Magnus and the Lorentz forces)
on vortices in superfluids put into periodic potentials at $T=0$. The case of
weak potential and the tight-binding limit described by the Bose-Hubbard model
were addressed. The analysis was based on the balance of true momentum and
quasimomentum. A special attention was paid to the superfluid close to the
superfluid-insulator transition. In this area of the phase diagram the theory
predicts the particle-hole symmetry line where the Magnus force changes sign
with respect to that expected from the sign of velocity circulation. Our
analysis has shown that the magnitude of the Magnus force is a continuous
function at crossing the particle-hole symmetry line. This challenges the
theory connecting the magnitude of the Magnus force with topological Chern
numbers and predicting a jump at crossing this line. Disagreement is explained
by the role of intrinsic pinning and guided vortex motion ignored in the
topological approach. It is one more evidence that in general topological
arguments are not sufficient for derivation of equations of vortex motion.


title:
Interface-driven ferromagnetism within the quantum wells of a rare earth
  titanate superlattice

abstract:
  Here we present polarized neutron reflectometry measurements exploring thin
film heterostructures comprised of a strongly correlated Mott state, GdTiO$_3$,
embedded with SrTiO$_3$ quantum wells. Our results reveal that the net
ferromagnetism inherent to the Mott GdTiO$_3$ matrix propagates into the
nominally nonmagnetic SrTiO$_3$ quantum wells and tracks the magnetic order
parameter of the host Mott insulating matrix. Beyond a well thickness of 5 SrO
layers, the magnetic moment within the wells is dramatically suppressed,
suggesting that quenched well magnetism comprises the likely origin of quantum
critical magnetotransport in this thin film architecture. Our data demonstrate
that the interplay between proximate exchange fields and polarity induced
carrier densities can stabilize extended magnetic states within SrTiO$_3$
quantum wells.


title:
Learning Discriminative Features using Encoder-Decoder type Deep Neural
  Nets

abstract:
  As machine learning is applied to an increasing variety of complex problems,
which are defined by high dimensional and complex data sets, the necessity for
task oriented feature learning grows in importance. With the advancement of
Deep Learning algorithms, various successful feature learning techniques have
evolved. In this paper, we present a novel way of learning discriminative
features by training Deep Neural Nets which have Encoder or Decoder type
architecture similar to an Autoencoder. We demonstrate that our approach can
learn discriminative features which can perform better at pattern
classification tasks when the number of training samples is relatively small in
size.


title: Object Recognition and Identification Using ESM Data

abstract:
  Recognition and identification of unknown targets is a crucial task in
surveillance and security systems. Electronic Support Measures (ESM) are one of
the most effective sensors for identification, especially for maritime and
air--to--ground applications. In typical surveillance systems multiple ESM
sensors are usually deployed along with kinematic sensors like radar. Different
ESM sensors may produce different types of reports ready to be sent to the
fusion center. The focus of this paper is to develop a new architecture for
target recognition and identification when non--homogeneous ESM and possibly
kinematic reports are received at the fusion center. The new fusion
architecture is evaluated using simulations to show the benefit of utilizing
different ESM reports such as attributes and signal level ESM data.


title:
Comment on "Fractional quantum mechanics" and "Fractional Schroedinger
  equation"

abstract:
  In this comment, we point out some shortcomings in two papers "Fractional
quantum mechanics" [Phys. Rev. E 62, 3135 (2000)] and "Fractional Schroedinger
equation" [Phys. Rev. E 66, 056108 (2002)]. We prove that the fractional
uncertainty relation does not hold generally. The probability continuity
equation in fractional quantum mechanics has a missing source term, which leads
to particle teleportation, i.e., a particle can teleport from one place to
another. Since the relativistic kinetic energy can be viewed as an approximate
realization of the fractional kinetic energy, the particle teleportation should
be an observable relativistic effect in quantum mechanics. With the help of
this concept, superconductivity could be viewed as the teleportation of
electrons from one side of a superconductor to another and superfluidity could
be viewed as the teleportation of helium atoms from one end of a capillary tube
to the other. We also point out how to teleport a particle to a destination.


title: A Herschel view of protoplanetary disks in the $\sigma$ Ori cluster

abstract:
  We present new Herschel PACS observations of 32 T Tauri stars in the young
($\sim$3 Myr) $\sigma$ Ori cluster. Most of our objects are K & M stars with
large excesses at 24 $\mu$m. We used irradiated accretion disk models of
D'Alessio et al. (2006) to compare their spectral energy distributions with our
observational data. We arrive at the following six conclusions. (i) The
observed disks are consistent with irradiated accretion disks systems. (ii)
Most of our objects (60%) can be explained by significant dust depletion from
the upper disk layers. (iii) Similarly, 61% of our objects can be modeled with
large disk sizes ($\rm R_{\rm d} \geq$ 100 AU). (iv) The masses of our disks
range between 0.03 to 39 $\rm M_{Jup}$, where 35% of our objects have disk
masses lower than 1 Jupiter. Although these are lower limits, high mass ($>$
0.05 M$_{\odot}$) disks, which are present e.g, in Taurus, are missing. (v) By
assuming a uniform distribution of objects around the brightest stars at the
center of the cluster, we found that 80% of our disks are exposed to external
FUV radiation of $300 \leq G_{0} \leq 1000$, which can be strong enough to
photoevaporate the outer edges of the closer disks. (vi) Within 0.6 pc from
$\sigma$ Ori we found forbidden emission lines of [NII] in the spectrum of one
of our large disk (SO662), but no emission in any of our small ones. This
suggests that this object may be an example of a photoevaporating disk.


title:
Hamiltonian Approach to Internal Wave-Current Interactions in a
  Two-Media Fluid with a Rigid Lid

abstract:
  We examine a two-media 2-dimensional fluid system consisting of a lower
medium bounded underneath by a flatbed and an upper medium with a free surface
with wind generated surface waves but considered bounded above by a lid by an
assumption that surface waves have negligible amplitude. An internal wave
driven by gravity which propagates in the positive $x$-direction acts as a free
common interface between the media. The current is such that it is zero at the
flatbed but a negative constant, due to an assumption that surface winds blow
in the negative $x$-direction, at the lid. We are concerned with the layers
adjacent to the internal wave in which there exists a depth dependent current
for which there is a greater underlying than overlying current. Both media are
considered incompressible and having non-zero constant vorticities. The
governing equations are written in canonical Hamiltonian form in terms of the
variables, associated to the wave (in a presence of a constant current). The
resultant equations of motion show that wave-current interaction is influenced
only by the current profile in the 'strip' adjacent to the internal wave.


title: Cultural Differences in E-Learning: Exploring New Dimensions

abstract:
  Rapid development of Internet and information technologies has gifted us with
a new and diverse mode of learning known as e-learning. In the current era,
e-learning has made rapid, influential, universal, interactive, vibrant, and
economic development. Now e-learning has become a global mode of education.
E-learning means the use of internet, computer and communications technologies
to acquire education. Learners with diverse social, cultural, economic,
linguistic, and religious backgrounds from all over the world are taking
benefits from e-learning. In e-learning, culture of target learners plays a
vital role and need to be explored for better results. Diversity of culture and
learning styles should keep under considerations while designing e-learning
environment. It may help to attain the required results. In this research work,
authors proposed and designed a novel architecture for e-learning system
incorporating cultural diversity of learners. The focus is to concentrate on
cultural factors from e-learning system. Furthermore; a prototype of the
proposed system is implemented for the validation of proposed architecture.


title: Classes of hydrodynamic and magnetohydrodynamic turbulent decay

abstract:
  We perform numerical simulations of decaying hydrodynamic and
magnetohydrodynamic turbulence. We classify our time-dependent solutions by
their evolutionary tracks in parametric plots between instantaneous scaling
exponents. We find distinct classes of solutions evolving along specific
trajectories toward points on a line of self-similar solutions. These
trajectories are determined by the underlying physics governing individual
cases, while the infrared slope of the initial conditions plays only a limited
role. In the helical case, even for a scale-invariant initial spectrum
(inversely proportional to wavenumber k), the solution evolves along the same
trajectory as for a Batchelor spectrum (proportional to k^4.


title: BRST symmetry and fictitious parameters

abstract:
  Our goal in this work is to present the variational method of fictitious
parameters and its connection with the BRST symmetry. Firstly we implement the
method in QED at zero temperature and then we extend the analysis to GQED at
finite temperature. As we will see the core of the study is the general
statement in gauge theories at finite temperature, assigned by Tyutin work,
that the physics does not depend on the gauge choices, covariant or not, due to
BRST symmetry.


title:
$\xi$-asymptotically uniformly smooth, $\xi$-asymptotically uniformly
  convex, and $(\beta)$ operators

abstract:
  For each ordinal $\xi$, we define the notions of $\xi$-asymptotically
uniformly smooth and $w^*$-$\xi$-asymptotically uniformly convex operators.
When $\xi=0$, these extend the notions of asymptotically uniformly smooth and
$w^*$-asymptotically uniformly convex Banach spaces. We give a complete
description of renorming results for these properties in terms of the Szlenk
index of the operator, as well as a complete description of the duality between
these two properties. We also define the notion of an operator with property
$(\beta)$ of Rolewicz which extends the notion of property $(\beta)$ for a
Banach space. We characterize those operators the domain and range of which can
be renormed so that the operator has property $(\beta)$ in terms of the Szlenk
index of the operator and its adjoint.


title: Angular dependence of primordial trispectra and CMB spectral distortions

abstract:
  Under the presence of anisotropic sources in the inflationary era, the
trispectrum of the primordial curvature perturbation has a very specific
angular dependence between each wavevector that is distinguishable from the one
encountered when only scalar fields are present, characterized by an angular
dependence described by Legendre polynomials. We examine the imprints left by
curvature trispectra on the $TT\mu$ bispectrum, generated by the correlation
between temperature anisotropies (T) and chemical potential spectral
distortions ($\mu$) of the Cosmic Microwave Background (CMB). Due to the
angular dependence of the primordial signal, the corresponding $TT\mu$
bispectrum strongly differs in shape from $TT\mu$ sourced by the usual $g_{\rm
NL}$ or $\tau_{\rm NL}$ local trispectra, enabling us to obtain an unbiased
estimation. From a Fisher matrix analysis, we find that, in a
cosmic-variance-limited (CVL) survey of $TT\mu$, a minimum detectable value of
the quadrupolar Legendre coefficient is $d_2 \sim 0.01$, which is 4 orders of
magnitude better than the best value attainable from the $TTTT$ CMB
trispectrum. In the case of an anisotropic inflationary model with a
$f(\phi)F^2$ interaction (coupling the inflaton field $\phi$ with a vector
kinetic term $F^2$), the size of the curvature trispectrum is related to that
of quadrupolar power spectrum asymmetry, $g_*$. In this case, a CVL measurement
of $TT\mu$ makes it possible to measure $g_*$ down to $10^{-3}$.


title: Constraining RRc candidates using SDSS colours

abstract:
  The light variations of first-overtone RR Lyrae stars and contact eclipsing
binaries can be difficult to distinguish. The Catalina Periodic Variable Star
catalog contains several misclassified objects, despite the classification
efforts by Drake et al. (2014). They used metallicity and surface gravity
derived from spectroscopic data (from the SDSS database) to rule out binaries.
Our aim is to further constrain the catalog using SDSS colours to estimate
physical parameters for stars that did not have spectroscopic data.


title: Second order singular pertubative theory for gravitational lenses

abstract:
  The extension of the singular perturbative approach to the second order is
presented in this paper. The general expansion to the second order is derived.
The second order expansion is considered as a small correction to the first
order expansion. Using this approach it is demonstrated that the second order
expansion is reducible to a first order expansion via a re-definition of the
first order pertubative fields. Even if in practice the second order correction
is small the reducibility of the second order expansion to the first order
expansion indicates a degeneracy problem. In general this degeneracy is hard to
break. A useful and simple second order approximation is the thin source
approximation which offers a direct estimation of the correction. The practical
application of the corrections derived in this paper are illustrated by using
an elliptical NFW lens model. The second order pertubative expansion provides a
noticeable improvement, even for the simplest case of thin source
approximation. To conclude it is clear that for accurate modelisation of
gravitational lenses using the perturbative method the second order
perturbative expansion should be considered. In particular an evaluation of the
degeneracy due to the second order term should be performed, for which the thin
source approximation is particularly useful.


title:
Analytical solutions for optical forces between two dielectric planar
  waveguides immersed in dielectric fluid media

abstract:
  We investigate optical (transverse gradient) forces between two high-index
dielectric planar waveguides immersed in low-index dielectric fluid media.
Complimentary to previous studies, we extend optical forces calculations, in
order to take into account a non-vacuum (and non-air) background medium, by
using the Minkowski stress tensor formulation; we derived a very simple set of
equations in terms of the effective refractive indexes of the waveguide
eigenmodes. We also used a normalized version of the dispersion relation method
to calculate the optical forces, in order to validate our results for different
dielectric fluid media. Excellent agreement between the two methods was
obtained for all analyzed cases. We show that, due to slot-waveguide effect,
the TM modes are more sensitive to changes in the fluid refractive index than
the TE ones. Furthermore, the repulsive optical force of the antisymmetric TM1
mode becomes stronger for higher refractive indexes, whereas the attractive
force of the symmetric TM0 mode becomes weaker. The methodology and results
presented in this work provide a rigorous analysis of nano-optomechanical
devices actuated by optical forces in a broader range of materials and
applications.


title: A Tutorial on Regularized Partial Correlation Networks

abstract:
  Recent years have seen an emergence of network modeling applied to moods,
attitudes, and problems in the realm of psychology. In this framework,
psychological variables are understood to directly affect each other rather
than being caused by an unobserved latent entity. In this tutorial, we
introduce the reader to estimating the most popular network model for
psychological data: the partial correlation network. We describe how
regularization techniques can be used to efficiently estimate a parsimonious
and interpretable network structure in psychological data. We show how to
perform these analyses in R and demonstrate the method in an empirical example
on post-traumatic stress disorder data. In addition, we discuss the effect of
the hyperparameter that needs to be manually set by the researcher, how to
handle non-normal data, how to determine the required sample size for a network
analysis, and provide a checklist with potential solutions for problems that
can arise when estimating regularized partial correlation networks.


title: Characterization of the skew cyclic codes over Fp+vFp

abstract:
  We study cyclic codes with arbitrary length over Fp+vFp where theta(v)=av, a
in Fp and v^2=0. We characterize all existing codes in case of O(theta)|n by
using certain projections from (Fp+vFp)[x;theta] to Fp[x]. We provide an
explicit expression for the ensemble of all possible codes. We also prove
useful properties of these codes in the case where O(theta)|n does not hold. We
provide results and examples to illustrate how the codes are constructed and
how their encoding and decoding are realized.


title:
On the Consistency of the Likelihood Maximization Vertex Nomination
  Scheme: Bridging the Gap Between Maximum Likelihood Estimation and Graph
  Matching

abstract:
  Given a graph in which a few vertices are deemed interesting a priori, the
vertex nomination task is to order the remaining vertices into a nomination
list such that there is a concentration of interesting vertices at the top of
the list. Previous work has yielded several approaches to this problem, with
theoretical results in the setting where the graph is drawn from a stochastic
block model (SBM), including a vertex nomination analogue of the Bayes optimal
classifier. In this paper, we prove that maximum likelihood (ML)-based vertex
nomination is consistent, in the sense that the performance of the ML-based
scheme asymptotically matches that of the Bayes optimal scheme. We prove
theorems of this form both when model parameters are known and unknown.
Additionally, we introduce and prove consistency of a related, more scalable
restricted-focus ML vertex nomination scheme. Finally, we incorporate vertex
and edge features into ML-based vertex nomination and briefly explore the
empirical effectiveness of this approach.


title:
Reconstructing the cosmic Horseshoe gravitational lens using the
  singular perturbative approach

abstract:
  The cosmic horseshoe gravitational lens is analyzed using the perturbative
approach. The two first order perturbative fields are expanded in Fourier
series. The source is reconstructed using a fine adaptive grid. The expansion
of the fields at order 2 produces a higher value of the chi-square. Expanding
at order 3 provides a very significant improvement, while order 4 does not
bring a significant improvement over order 3. The presence of the order 3 terms
is not a consequence of limiting the perturbative expansion to the first order.
The amplitude and signs of the third order terms are recovered by including the
contribution of the other group members. This analysis demonstrates that the
fine details of the potential of the lens could be recovered independently of
any assumptions by using the perturbative approach.


title: On the distribution of cross-validated Mahalanobis distances

abstract:
  We present analytical expressions for the means and covariances of the sample
distribution of the cross-validated Mahalanobis distance. This measure has
proven to be especially useful in the context of representational similarity
analysis (RSA) of neural activity patterns as measured by means of functional
magnetic resonance imaging (fMRI). These expressions allow us to construct a
normal approximation to the estimated distances, which in turn enables powerful
inference on the measured statistics. Using the results, the difference between
two distances can be statistically assessed, and the measured structure of the
distances can be efficiently compared to predictions from computational models.


title: Clustering and pasta phases in nuclear density functional theory

abstract:
  Nuclear density functional theory (DFT) is the tool of choice in describing
properties of complex nuclei and intricate phases of bulk nucleonic matter. It
is a microscopic approach based on an energy density functional representing
the nuclear interaction. An attractive feature of nuclear DFT is that it can be
applied to both finite nuclei and pasta phases appearing in the inner crust of
neutron stars. While nuclear pasta clusters in a neutron star can be easily
characterized through their density distributions, the level of clustering of
nucleons in a nucleus can often be difficult to assess. To this end, we use the
concept of nucleonic localization. We demonstrate that the localization measure
provides us with fingerprints of clusters in light and heavy nuclei, including
fissioning systems. Furthermore we investigate the rod-like pasta phase using
twist-averaged boundary conditions, which enable calculations in finite volumes
accessible by state of the art DFT solvers.


title:
Amplitude Higgs mode and admittance in superconductors with a moving
  condensate

abstract:
  We consider the amplitude (Higgs) mode in a superconductor with a condensate
flow (supercurrent). We demonstrate that, in this case, the amplitude mode
corresponding to oscillations $\delta |\Delta|_{\Omega} \exp(i \Omega t)$ of
the superconducting gap is excited by an external ac electric field
$\mathbf{E}_{\Omega} \exp(i \Omega t)$ already in the first order in
$|\mathbf{E}_{\Omega}|$, so that ${\delta |\Delta|_{\Omega} \propto
(\mathbf{v}_{0} \mathbf{E}_{\Omega})}$, where $\mathbf{v}_{0}$ is the velocity
of the condensate. The frequency dependence $\delta |\Delta|_{\Omega}$ has a
resonance shape with a maximum at ${\Omega = 2 \Delta}$. In contrast to the
standard situation without the condensate flow, the oscillations of the
amplitude $\delta |\Delta(t)|$ contribute to the admittance $Y_{\Omega}$. We
provide a formula for admittance of a superconductor with a supercurrent. The
predicted effect opens new ways of experimental investigation of the amplitude
mode in superconductors and materials with superconductivity competing with
other states.


title: Efficient estimation of perturbative error with cellular automata

abstract:
  From celestial mechanics to quantum theory of atoms and molecules,
perturbation theory has played a central role in natural sciences. Particularly
in quantum mechanics, the amount of information needed for specifying the state
of a many-body system commonly scales exponentially as the system size. This
poses a fundamental difficulty in using perturbation theory at arbitrary order.
As one computes the terms in the perturbation series at increasingly higher
orders, it is often important to determine whether the series converges and if
so, what is an accurate estimation of the total error that comes from the next
order of perturbation up to infinity. Here we present a set of efficient
algorithms that compute tight upper bounds to perturbation terms at arbitrary
order. We argue that these tight bounds often take the form of symmetric
polynomials on the parameter of the quantum system. We then use cellular
automata as our basic model of computation to compute the symmetric polynomials
that account for all of the virtual transitions at any given order. At any
fixed order, the computational cost of our algorithm scales polynomially as a
function of the system size. We present a non-trivial example which shows that
our error estimation is nearly tight with respect to exact calculation.


title: Efficient Estimation in the Tails of Gaussian Copulas

abstract:
  We consider the question of efficient estimation in the tails of Gaussian
copulas. Our special focus is estimating expectations over multi-dimensional
constrained sets that have a small implied measure under the Gaussian copula.
We propose three estimators, all of which rely on a simple idea: identify
certain \emph{dominating} point(s) of the feasible set, and appropriately shift
and scale an exponential distribution for subsequent use within an importance
sampling measure. As we show, the efficiency of such estimators depends
crucially on the local structure of the feasible set around the dominating
points. The first of our proposed estimators $\estOpt$ is the
"full-information" estimator that actively exploits such local structure to
achieve bounded relative error in Gaussian settings. The second and third
estimators $\estExp$, $\estLap$ are "partial-information" estimators, for use
when complete information about the constraint set is not available, they do
not exhibit bounded relative error but are shown to achieve polynomial
efficiency. We provide sharp asymptotics for all three estimators. For the
NORTA setting where no ready information about the dominating points or the
feasible set structure is assumed, we construct a multinomial mixture of the
partial-information estimator $\estLap$ resulting in a fourth estimator
$\estNt$ with polynomial efficiency, and implementable through the ecoNORTA
algorithm. Numerical results on various example problems are remarkable, and
consistent with theory.


title: Onset of meso-scale turbulence in living fluids

abstract:
  Meso-scale turbulence is an innate phenomenon, distinct from inertial
turbulence, that spontaneously occurs at zero-Reynolds number in fluidized
biological systems. This spatio-temporal disordered flow radically changes
nutrient and molecular transport in living fluids and can strongly affect the
collective behaviour in prominent biological processes, including biofilm
formation, morphogenesis and cancer invasion. Despite its crucial role in such
physiological processes, understanding meso-scale turbulence and any relation
to classical inertial turbulence remains obscure. Here, we show how the motion
of active matter along a micro-channel transitions to meso-scale turbulence
through the evolution of disordered patches (active puffs) from an absorbing
state of flow vortex-lattices. We demonstrate that the critical behaviour of
this transition to meso-scale turbulence in a channel belongs to the directed
percolation universality class. This finding bridges our understanding of the
onset of zero-Reynolds number meso-scale turbulence and traditional
scale-invariant turbulence, therefore generalizing theories on the onset of
turbulence in confinement to the distinct classes of incoherent flows observed
in biological fluids.


title: Deciding the Chromatic Numbers of Algebraic Hypergrahs

abstract:
  For each infinite cardinal k, the set of algebraic hypergraphs having
chromatic number no larger than k is decidable.


title: Detecting Rotational Superradiance in Fluid Laboratories

abstract:
  Rotational superradiance was predicted theoretically decades ago, and is
chiefly responsible for a number of important effects and phenomenology in
black-hole physics. However, rotational superradiance has never been observed
experimentally. Here, with the aim of probing superradiance in the lab, we
investigate the behavior of sound and surface waves in fluids resting in a
circular basin at the center of which a rotating cylinder is placed. We show
that with a suitable choice for the material of the cylinder, surface and sound
waves are amplified. Two types of instabilities are studied: one sets in
whenever superradiant modes are confined near the rotating cylinder and the
other, which does not rely on confinement, corresponds to a local excitation of
the cylinder. Our findings are experimentally testable in existing fluid
laboratories and, hence, offer experimental exploration and comparison of
dynamical instabilities arising from rapidly rotating boundary layers in
astrophysical as well as in fluid dynamical systems.


title: Feebly Interacting Dark Matter Particle as the Inflaton

abstract:
  We present a scenario where a $Z_2$-symmetric scalar field $\phi$ first
drives cosmic inflation, then reheats the Universe but remains
out-of-equilibrium itself, and finally comprises the observed dark matter
abundance, produced by particle decays \`{a} la freeze-in mechanism. We work
model-independently without specifying the interactions of the scalar field
besides its self-interaction coupling, $\lambda\phi^4$, non-minimal coupling to
gravity, $\xi\phi^2R$, and coupling to another scalar field, $g\phi^2\sigma^2$.
We find the scalar field $\phi$ serves both as the inflaton and a dark matter
candidate if $10^{-9}\lesssim \lambda\lesssim g\lesssim 10^{-7}$ and $3
\rm{keV} \lesssim m_{\rm \phi}\lesssim 85 \rm{MeV}$ for $\xi=\mathcal{O}(1)$.
Such a small value of the non-minimal coupling is also found to be of the right
magnitude to produce the observed curvature perturbation amplitude within the
scenario. We also discuss how the model may be distinguished from other
inflationary models of the same type by the next generation CMB satellites.


title:
Effects of Stellar Rotation in Parker's Hydrodynamic Stellar Wind Model:
  How Protostars and Strong Rotators Lose their Angular Momentum Fast

abstract:
  The effects of the stellar rotation and the consequent azimuthal stellar wind
flow in Parker's [9] hydrodynamic stellar wind model are discussed. Of special
interest is the emergence of a whole new hydrodynamic physics via a new
critical point in the stellar wind flow, which supersedes the critical point in
Parker's [9] hydrodynamic model. The effect of the stellar rotation is shown to
cause the new critical point to occur lower in the corona, so the stellar wind
experiences a stronger afterburner (as in an aircraft jet engine) action in the
corona. For strong rotators, the new critical point is shown to occur at a
fixed location for a given star, determined only by the basic stellar
parameters like the mass M and the angular velocity, the variations in the
stellar wind environment notwithstanding. The stellar rotation leads to
stronger density fall-off and enhanced acceleration of the stellar wind at
large distances from the star - this effect materializes even close to the
star, for strong rotators. The stellar rotation causes the physical throat
section of the effective de Laval nozzle associated with the stellar wind flow
to become narrower, indicative of an enhanced flow acceleration. Thus, the
stellar rotation leads to tenuous and faster stellar wind flows without change
in the mass flux, and hence provides an efficient physical mechanism for
protostars and strong rotators to lose their angular momentum quickly.


title: One-Shot Session Recommendation Systems with Combinatorial Items

abstract:
  In recent years, content recommendation systems in large websites (or
\emph{content providers}) capture an increased focus. While the type of content
varies, e.g.\ movies, articles, music, advertisements, etc., the high level
problem remains the same. Based on knowledge obtained so far on the user,
recommend the most desired content. In this paper we present a method to handle
the well known user-cold-start problem in recommendation systems. In this
scenario, a recommendation system encounters a new user and the objective is to
present items as relevant as possible with the hope of keeping the user's
session as long as possible. We formulate an optimization problem aimed to
maximize the length of this initial session, as this is believed to be the key
to have the user come back and perhaps register to the system. In particular,
our model captures the fact that a single round with low quality recommendation
is likely to terminate the session. In such a case, we do not proceed to the
next round as the user leaves the system, possibly never to seen again. We
denote this phenomenon a \emph{One-Shot Session}. Our optimization problem is
formulated as an MDP where the action space is of a combinatorial nature as we
recommend in each round, multiple items. This huge action space presents a
computational challenge making the straightforward solution intractable. We
analyze the structure of the MDP to prove monotone and submodular like
properties that allow a computationally efficient solution via a method denoted
by \emph{Greedy Value Iteration} (G-VI).


title:
Remarks on log Calabi--Yau structure of varieties admitting polarized
  endomorphism

abstract:
  We discuss the Calabi--Yau type structure of normal projective surfaces and
Mori dream spaces admitting a non-trivial polarized endomorphism.


title:
MIMO Wiretap Channel under Receiver Side Power Constraints with
  Applications to Wireless Power Transfer and Cognitive Radio

abstract:
  We consider the multiple-input multiple-output (MIMO) wiretap channel under a
minimum receiver-side power constraint in addition to the usual maximum
transmitter-side power constraint. This problem is motivated by energy
harvesting communications with wireless energy transfer, where an added goal is
to deliver a minimum amount of energy to a receiver in addition to delivering
secure data to another receiver. In this paper, we characterize the exact
secrecy capacity of the MIMO wiretap channel under transmitter and
receiver-side power constraints. We first show that solving this problem is
equivalent to solving the secrecy capacity of the wiretap channel under a
double-sided correlation matrix constraint on the channel input. We show the
converse by extending the channel enhancement technique to our case. We present
two achievable schemes that achieve the secrecy capacity: the first achievable
scheme uses a Gaussian codebook with a fixed mean, and the second achievable
scheme uses artificial noise (or cooperative jamming) together with a Gaussian
codebook. The role of the mean or the artificial noise is to enable energy
transfer without sacrificing from the secure rate. This is the first instance
of a channel model where either the use of a mean signal or the use of channel
prefixing via artificial noise is strictly necessary for the MIMO wiretap
channel. We then extend our work to consider a maximum receiver-side power
constraint. This problem is motivated by cognitive radio applications, where an
added goal is to decrease the received signal energy (interference temperature)
at a receiver. We further extend our results to: requiring receiver-side power
constraints at both receivers; considering secrecy constraints at both
receivers to study broadcast channels with confidential messages; and removing
the secrecy constraints to study the classical broadcast channel.


title:
SMISS: A protein function prediction server by integrating multiple
  sources

abstract:
  SMISS is a novel web server for protein function prediction. Three different
predictors can be selected for different usage. It integrates different sources
to improve the protein function prediction accuracy, including the query
protein sequence, protein-protein interaction network, gene-gene interaction
network, and the rules mined from protein function associations. SMISS
automatically switch to ab initio protein function prediction based on the
query sequence when there is no homologs in the database. It takes fasta format
sequences as input, and several sequences can submit together without
influencing the computation speed too much. PHP and Perl are two primary
programming language used in the server. The CodeIgniter MVC PHP web framework
and Bootstrap front-end framework are used for building the server. It can be
used in different platforms in standard web browser, such as Windows, Mac OS X,
Linux, and iOS. No plugins are needed for our website. Availability:
http://tulip.rnet.missouri.edu/profunc/.


title:
How to understand the underlying structures of $X(4140)$, $X(4274)$,
  $X(4500)$ and $X(4700)$

abstract:
  We investigate the possible rescattering effects which may contribute to the
process $B^+\to J/\psi\phi K^+$. It is shown that the $D_{s}^{*+}D_{s}^-$
rescattering via the open-charmed meson loops, and $\psi^\prime \phi$
rescattering via the $\psi^\prime K_1$ loops may simulate the structures of
$X(4140)$ and $X(4700)$, respectively. However, if the quantum numbers of
$X(4274)$ ($X(4500)$) are $1^{++}$ ($0^{++}$), it is hard to to ascribe the
observation of $X(4274)$ and $X(4500)$ to the $P$-wave threshold rescattering
effects, which implies that $X(4274)$ and $X(4500)$ could be genuine
resonances. We also suggest that $X(4274)$ may be the conventional orbitally
excited state $\chi_{c1}(3P)$.


title: Precision Prediction of the Log Power Spectrum

abstract:
  At translinear scales, the log power spectrum captures significantly more
cosmological information than the standard power spectrum. At high wavenumbers
$k$, the Fisher information in the standard power spectrum $P(k)$ fails to
increase in proportion to $k$ in part due to correlations between large- and
small-scale modes. As a result, $P(k)$ suffers from an information plateau on
these translinear scales, so that analysis with the standard power spectrum
cannot access the information contained in these small-scale modes. The log
power spectrum $P_A(k)$, on the other hand, captures the majority of this
otherwise lost information. Until now there has been no means of predicting the
amplitude of the log power spectrum apart from cataloging the results of
simulations. We here present a cosmology-independent prescription for the log
power spectrum; this prescription displays accuracy comparable to that of Smith
et al. (2003), over a range of redshifts and smoothing scales, and for
wavenumbers up to $1.5h$ Mpc$^{-1}$.


title: Algebraic Methods for Quantum Codes on Lattices

abstract:
  This is a note from a series of lectures at Encuentro Colombiano de
Computacion Cuantica, Universidad de los Andes, Bogota, Colombia, 2015. The
purpose is to introduce additive quantum error correcting codes, with emphasis
on the use of binary representation of Pauli matrices and modules over a
translation group algebra. The topics include symplectic vector spaces,
Clifford group, cleaning lemma, an error correcting criterion, entanglement
spectrum, implications of the locality of stabilizer group generators, and the
classification of translation-invariant one-dimensional additive codes and
two-dimensional CSS codes with large code distances. In particular, we describe
an algorithm to find a Clifford quantum circuit (CNOTs) to transform any
two-dimensional translation-invariant CSS code on qudits of a prime dimension
with code distance being the linear system size, into a tensor product of
finitely many copies of the qudit toric code and a product state. Thus, the
number of embedded toric codes is the complete invariant of these CSS codes
under local Clifford circuits.


title: Fermion Condensation and Gapped Domain Walls in Topological Orders

abstract:
  We propose the concept of fermion condensation in bosonic topological orders
in two spatial dimensions. Fermion condensation can be realized as gapped
domain walls between bosonic and fermionic topological orders, which are
thought of as a real-space phase transitions from bosonic to fermionic
topological orders. This generalizes the previous idea of understanding boson
condensation as gapped domain walls between bosonic topological orders. We show
that generic fermion condensation obeys a Hierarchy Principle by which it can
be decomposed into a boson condensation followed by a minimal fermion
condensation, which involves a single self-fermion that is its own
anti-particle and has unit quantum dimension. We then develop the rules of
minimal fermion condensation, which together with the known rules of boson
condensation, provides a full set of rules of fermion condensation. Our studies
point to an exact mapping between the Hilbert spaces of a bosonic topological
order and a fermionic topological order that share a gapped domain wall.


title:
An Underappreciated Radiation Hazard from High Voltage Electrodes in
  Vacuum

abstract:
  The use of high voltage (HV) electrodes in vacuum is commonplace in physics
laboratories. In such systems, it has long been known that electron emission
from an HV cathode can lead to bremsstrahlung X-rays; indeed, this is the basic
principle behind the operation of standard X-ray sources. However, in
laboratory setups where X-ray production is not the goal and no electron source
is deliberately introduced, field-emitted electrons accelerated by HV can
produce X-rays as an unintended hazardous byproduct. Both the level of hazard
and the safe operating regimes for HV vacuum electrode systems are not widely
appreciated, at least in university laboratories. A reinforced awareness of the
radiation hazards associated with vacuum HV setups would be beneficial. We
present a case study of a HV vacuum electrode device operated in a university
atomic physics laboratory. We describe the characterisation of the observed
X-ray radiation, its relation to the observed leakage current in the device,
the steps taken to contain and mitigate the radiation hazard, and suggest
safety guidelines.


title: Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab

abstract:
  MeV-GeV dark matter (DM) is theoretically well motivated but remarkably
unexplored. This proposal presents the MeV-GeV DM discovery potential for a
$\sim$1 m$^3$ segmented CsI(Tl) scintillator detector placed downstream of the
Hall A beam-dump at Jefferson Lab, receiving up to 10$^{22}$
electrons-on-target (EOT) in 285 days. This experiment (Beam-Dump eXperiment or
BDX) would be sensitive to elastic DM-electron and to inelastic DM scattering
at the level of 10 counts per year, reaching the limit of the neutrino
irreducible background. The distinct signature of a DM interaction will be an
electromagnetic shower of few hundreds of MeV, together with a reduced activity
in the surrounding active veto counters. A detailed description of the DM
particle $\chi$ production in the dump and subsequent interaction in the
detector has been performed by means of Monte Carlo simulations. Different
approaches have been used to evaluate the expected backgrounds: the cosmogenic
background has been extrapolated from the results obtained with a prototype
detector running at INFN-LNS (Italy), while the beam-related background has
been evaluated by GEANT4 Monte Carlo simulations. The proposed experiment will
be sensitive to large regions of DM parameter space, exceeding the discovery
potential of existing and planned experiments in the MeV-GeV DM mass range by
up to two orders of magnitude.


title:
VDES J2325-5229 a z=2.7 gravitationally lensed quasar discovered using
  morphology independent supervised machine learning

abstract:
  We present the discovery and preliminary characterization of a
gravitationally lensed quasar with a source redshift $z_{s}=2.74$ and image
separation of $2.9"$ lensed by a foreground $z_{l}=0.40$ elliptical galaxy.
Since the images of gravitationally lensed quasars are the superposition of
multiple point sources and a foreground lensing galaxy, we have developed a
morphology independent multi-wavelength approach to the photometric selection
of lensed quasar candidates based on Gaussian Mixture Models (GMM) supervised
machine learning. Using this technique and $gi$ multicolour photometric
observations from the Dark Energy Survey (DES), near IR $JK$ photometry from
the VISTA Hemisphere Survey (VHS) and WISE mid IR photometry, we have
identified a candidate system with two catalogue components with $i_{AB}=18.61$
and $i_{AB}=20.44$ comprised of an elliptical galaxy and two blue point
sources. Spectroscopic follow-up with NTT and the use of an archival AAT
spectrum show that the point sources can be identified as a lensed quasar with
an emission line redshift of $z=2.739\pm0.003$ and a foreground early type
galaxy with $z=0.400\pm0.002$. We model the system as a single isothermal
ellipsoid and find the Einstein radius $\theta_E \sim 1.47"$, enclosed mass
$M_{enc} \sim 4 \times 10^{11}$M$_{\odot}$ and a time delay of $\sim$52 days.
The relatively wide separation, month scale time delay duration and high
redshift make this an ideal system for constraining the expansion rate beyond a
redshift of 1.


title: Outbursts in two new cool pulsating DA white dwarfs

abstract:
  The unprecedented extent of coverage provided by Kepler observations recently
revealed outbursts in two hydrogen-atmosphere pulsating white dwarfs (DAVs)
that cause hours-long increases in the overall mean flux of up to 14%. We have
identified two new outbursting pulsating white dwarfs in K2, bringing the total
number of known outbursting white dwarfs to four. EPIC 211629697, with T_eff =
10,780 +/- 140 K and log(g) = 7.94 +/- 0.08, shows outbursts recurring on
average every 5.0 d, increasing the overall flux by up to 15%. EPIC 229227292,
with T_eff = 11,190 +/- 170 K and log(g) = 8.02 +/- 0.05, has outbursts that
recur roughly every 2.4 d with amplitudes up to 9%. We establish that only the
coolest pulsating white dwarfs within a small temperature range near the cool,
red edge of the DAV instability strip exhibit these outbursts.


title: The Tully-Fisher Relation of COLD GASS Galaxies

abstract:
  We present the stellar mass (M_*) and Wide-Field Infrared Survey Explorer
(WISE) absolute Band 1 magnitude (M_W1) Tully-Fisher relations (TFRs) of
subsets of galaxies from the CO Legacy Database for the Galex Arecibo SDSS
Survey (COLD GASS). We examine the benefits and drawbacks of several commonly
used fitting functions in the context of measuring CO(1-0) line widths (and
thus rotation velocities), favouring the Gaussian Double Peak function. We find
the M_W1 and M_* TFR, for a carefully selected sub-sample, to be M_W1 = (-7.1
+/- 0.6) [log(W_50/sin i) - 2.58] - 23.83 +/- 0.09 and log(M_*/M_Sun) = (3.3
+/- 0.3) [log(W_50/sin i) - 2.58] + 10.51 +/- 0.04, respectively, where W_50 is
the width of a galaxy's CO(1-0) integrated profile at 50% of its maximum and
the inclination i is derived from the galaxy axial ratio measured on the SDSS
r-band image. We find no evidence for any significant offset between the TFRs
of COLD GASS galaxies and those of comparison samples of similar redshifts and
morphologies. The slope of the COLD GASS M_* TFR agrees with the relation of
Pizagno et al. (2005). However, we measure a comparatively shallower slope for
the COLD GASS M_W1 TFR as compared to the relation of Tully & Pierce (2000). We
attribute this to the fact that the COLD GASS sample comprises galaxies of
various (late-type) morphologies. Nevertheless, our work provides a robust
reference point with which to compare future CO TFR studies.


title:
Merger-driven evolution of the effective stellar initial mass function
  of massive early-type galaxies

abstract:
  The stellar initial mass function (IMF) of early-type galaxies is the
combination of the IMF of the stellar population formed in-situ and that of
accreted stellar populations. Using as an observable the effective IMF
$\alpha_{IMF}$, defined as the ratio between the true stellar mass of a galaxy
and the stellar mass inferred assuming a Salpeter IMF, we present a theoretical
model for its evolution as a result of dry mergers. We use a simple dry merger
evolution model, based on cosmological $N$-body simulations, together with
empirically motivated prescriptions for the IMF to make predictions for how the
effective IMF of massive early-type galaxies changes from $z=2$ to $z=0$. We
find that the IMF normalization of individual galaxies becomes lighter with
time. At fixed velocity dispersion, $\alpha_{IMF}$ is predicted to be constant
with redshift. Current constraints on the evolution of the IMF are in slight
tension with this prediction, even though systematic uncertainties prevent a
conclusive statement. The correlation of $\alpha_{IMF}$ with stellar mass
becomes shallower with time, while the correlation between $\alpha_{IMF}$ and
velocity dispersion is mostly preserved by dry mergers. We also find that dry
mergers can mix the dependence of the IMF on stellar mass and velocity
dispersion, making it challenging to infer, from $z=0$ observations of global
galactic properties, what is the quantity that is originally coupled with the
IMF.


title:
$\alpha'$ Inflation: Moduli Stabilisation and Observable Tensors from
  Higher Derivatives

abstract:
  The leading order dynamics of the type IIB Large Volume Scenario is
characterised by the interplay between $\alpha'$ and non-perturbative effects
which fix the overall volume and all local blow-up modes leaving (in general)
several flat directions. In this paper we show that, in an arbitrary Calabi-Yau
with at least one blow-up mode resolving a point-like singularity, any
remaining flat directions can be lifted at subleading order by the inclusions
of higher derivative $\alpha'$ corrections. We then focus on simple fibred
cases with one remaining flat direction which can behave as an inflaton if its
potential is generated by both higher derivative $\alpha'$ and winding loop
corrections. Natural values of the underlying parameters give a spectral index
in agreement with observational data and a tensor-to-scalar ratio of order
$r=0.01$ which could be observed by forthcoming CMB experiments. Dangerous
corrections from higher dimensional operators are suppressed due to the
presence of an approximate non-compact shift symmetry.


title: Topological field theories on manifolds with Wu structures

abstract:
  We construct invertible field theories generalizing abelian prequantum spin
Chern-Simons theory to manifolds of dimension 4k+3 endowed with a Wu structure
of degree 2k+2. After analysing the anomalies of a certain discrete symmetry,
we gauge it, producing topological field theories whose path integral reduces
to a finite sum, akin to Dijkgraaf-Witten theories. We take a general point of
view where the Chern-Simons gauge group and its couplings are encoded in a
local system of integral lattices. The Lagrangian of these theories has to be
interpreted as a class in a generalized cohomology theory in order to obtain a
gauge invariant action. We develop a computationally friendly cochain model for
this generalized cohomology and use it in a detailed study of the properties of
the Wu Chern-Simons action. In the three-dimensional spin case, the latter
provides a definition of the "fermionic correction" introduced recently in the
literature on fermionic symmetry protected topological phases. In order to
construct the state space of the gauged theories, we develop an analogue of
geometric quantization for finite abelian groups endowed with a skew-symmetric
pairing. The physical motivation for this work comes from the fact that in the
k = 1 case, the gauged 7-dimensional topological field theories constructed
here are essentially the anomaly field theories of the 6-dimensional conformal
field theories with (2,0) supersymmetry, as will be discussed elsewhere.


title: White dwarf pollution by planets in stellar binaries

abstract:
  Approximately $0.2 \pm 0.2$ of white dwarfs (WDs) show signs of pollution by
metals, which is likely due to the accretion of tidally disrupted planetary
material. Models invoking planet-planet interactions after WD formation
generally cannot explain pollution at cooling times of several Gyr. We consider
a scenario in which a planet is perturbed by Lidov-Kozai oscillations induced
by a binary companion and exacerbated by stellar mass loss, explaining
pollution at long cooling times. Our computed accretion rates are consistent
with observations assuming planetary masses between $\sim 0.01$ and
$1\,M_\mathrm{Mars}$, although nongravitational effects may already be
important for masses $\lesssim 0.3 \, M_\mathrm{Mars}$. The fraction of
polluted WDs in our simulations, $\sim 0.05$, is consistent with observations
of WDs with intermediate cooling times between $\sim 0.1$ and 1 Gyr. For
cooling times $\lesssim 0.1$ Gyr and $\gtrsim 1$ Gyr, our scenario cannot
explain the high observed pollution fractions of up to 0.7. Nevertheless, our
results motivate searches for companions around polluted WDs.


title:
Control of spatial correlations between Rydberg excitations using rotary
  echo

abstract:
  We manipulate correlations between Rydberg excitations in cold atom samples
using a rotary-echo technique. The correlations are due to interactions between
the Rydberg atoms. In the rotary-echo excitation sequence, the phase of the
excitation pulse is flipped at a selected time during the pulse. We measure the
resultant change in the spatial pair correlation function of the excitations
via direct position-sensitive atom imaging. For zero detuning of the lasers
from the interaction-free Rydberg-excitation resonance, the pair-correlation
value at the most likely nearest-neighbor Rydberg-atom distance is
substantially enhanced when the phase is flipped at the middle of the
excitation pulse. In this case, the rotary echo eliminates most uncorrelated
(un-paired) atoms, leaving an abundance of correlated atom pairs at the end of
the sequence. In off-resonant cases, a complementary behavior is observed. We
further characterize the effect of the rotary-echo excitation sequence on the
excitation-number statistics of the atom sample.


title: Electron contribution to $(g-2)_\mu$ at four loops

abstract:
  In this contribution we summarize the recent calculation of the complete
electron contribution to the anomalous magnetic moment of the muon at four-loop
order.


title:
An Aggregate and Iterative Disaggregate Algorithm with Proven Optimality
  in Machine Learning

abstract:
  We propose a clustering-based iterative algorithm to solve certain
optimization problems in machine learning, where we start the algorithm by
aggregating the original data, solving the problem on aggregated data, and then
in subsequent steps gradually disaggregate the aggregated data. We apply the
algorithm to common machine learning problems such as the least absolute
deviation regression problem, support vector machines, and semi-supervised
support vector machines. We derive model-specific data aggregation and
disaggregation procedures. We also show optimality, convergence, and the
optimality gap of the approximated solution in each iteration. A computational
study is provided.


title: Diagrammatic Monte Carlo for Dual Fermions

abstract:
  We introduce a numerical algorithm to stochastically sample the dual fermion
perturbation series around the dynamical mean field theory, generating all
topologies of two-particle interaction vertices. We show results in the weak
and strong coupling regime of the half-filled Hubbard model in two dimensions,
illustrating that the method converges quickly where dynamical mean field
theory is a good approximation, and show that corrections are large in the
strong correlation regime at intermediate interaction. The fast convergence of
dual corrections to dynamical mean field results illustrates the power of the
approach and opens a practical avenue towards the systematic inclusion of
non-local correlations in correlated materials simulations. An analysis of the
frequency scale shows that only low-frequency propagators contribute
substantially to the diagrams, putting the inclusion of higher order vertices
within reach.


title: Supersymmetric Tensor Hierarchies from Superspace Cohomology

abstract:
  In this set of lectures we give a pedagogical introduction to the way in
which the nilpotency of a super-de Rham operator can be exploited for the
construction of gauge theories in superspace. We begin with a discussion of how
the super-geometric closure conditions can be solved by simply computing the
cocycles of the super-algebra. The next couple lectures are then devoted to
applying this idea to extensions of the standard super-de Rham complex. This
eventually results in a geometric "trivialization" of the consistency
conditions required for non-abelian tensor hierarchies. Although this is a
general conclusion, we focus specifically on the hierarchy obtained by
compactifying the 3-form gauge field of 11D supergravity to 4D, $N = 1$
superspace. In the final lecture, we use the cohomological arguments developed
herein to provide a geometric construction of the non-trivial Chern-Simons-type
invariant in that tensor hierarchy and comment on generalizations. These
lectures are based on a series of talks given at Texas A&M University from
March 21-25.


title:
H0LiCOW IV. Lens mass model of HE 0435-1223 and blind measurement of its
  time-delay distance for cosmology

abstract:
  Strong gravitational lenses with measured time delays between the multiple
images allow a direct measurement of the time-delay distance to the lens, and
thus a measure of cosmological parameters, particularly the Hubble constant,
$H_{0}$. We present a blind lens model analysis of the quadruply-imaged quasar
lens HE 0435-1223 using deep Hubble Space Telescope imaging, updated time-delay
measurements from the COSmological MOnitoring of GRAvItational Lenses
(COSMOGRAIL), a measurement of the velocity dispersion of the lens galaxy based
on Keck data, and a characterization of the mass distribution along the line of
sight. HE 0435-1223 is the third lens analyzed as a part of the $H_{0}$ Lenses
in COSMOGRAIL's Wellspring (H0LiCOW) project. We account for various sources of
systematic uncertainty, including the detailed treatment of nearby perturbers,
the parameterization of the galaxy light and mass profile, and the regions used
for lens modeling. We constrain the effective time-delay distance to be
$D_{\Delta t} = 2612_{-191}^{+208}~\mathrm{Mpc}$, a precision of 7.6%. From HE
0435-1223 alone, we infer a Hubble constant of $H_{0} =
73.1_{-6.0}^{+5.7}~\mathrm{km~s^{-1}~Mpc^{-1}}$ assuming a flat $\Lambda$CDM
cosmology. The cosmographic inference based on the three lenses analyzed by
H0LiCOW to date is presented in a companion paper (H0LiCOW Paper V).


title:
PRIMME_SVDS: A High-Performance Preconditioned SVD Solver for Accurate
  Large-Scale Computations

abstract:
  The increasing number of applications requiring the solution of large scale
singular value problems have rekindled interest in iterative methods for the
SVD. Some promising recent ad- vances in large scale iterative methods are
still plagued by slow convergence and accuracy limitations for computing
smallest singular triplets. Furthermore, their current implementations in
MATLAB cannot address the required large problems. Recently, we presented a
preconditioned, two-stage method to effectively and accurately compute a small
number of extreme singular triplets. In this research, we present a
high-performance software, PRIMME SVDS, that implements our hybrid method based
on the state-of-the-art eigensolver package PRIMME for both largest and
smallest singular values. PRIMME SVDS fills a gap in production level software
for computing the partial SVD, especially with preconditioning. The numerical
experiments demonstrate its superior performance compared to other
state-of-the-art software and its good parallel performance under strong and
weak scaling.


title:
Comment on "Tip induced unconventional superconductivity on Weyl
  semimetal TaAs" [arXiv:1607.00513]

abstract:
  Recently, Wang $et$ $al.$ have reported the observation of "unconventional
superconductivity" in the Weyl semimetal TaAs [arXiv:1607.00513]. The authors
have written "\textit{A conductance plateau and sharp double dips are observed
in the point contact spectra, indicating p-wave like unconventional
superconductivity. Furthermore, the zero bias conductance peak in low
temperature regime is detected, suggesting potentially the existence of
Majorana zero modes. The experimentally observed tunneling spectra can be
interpreted with a novel mirror-symmetry protected topological superconductor
induced in TaAs, which can exhibit zero bias and double finite bias peaks, and
double conductance dips in the measurements}." In this comment we show that for
a superconducting point contact, the features like a zero-bias conductance
peak, a plateau and single or multiple conductance dips might arise due to
simple contact-heating related effects. Such features are routinely observed in
point contacts involving a wide variety of superconductors when the experiments
are not performed in the right regime of mesoscopic transport. We also show
that the data presented by Wang $et$ $al.$ in a single transport regime of
point contact do not confirm tip induced superconductivity (TISC). Even if it
is assumed that Wang $et$ $al.$ achieved TISC on TaAs, all the spectra that
they have reported show striking similarities with the type of spectra expected
in thermal regime of transport. Such data cannot be used for extracting any
spectroscopic information and based on such data any discussion on "p-wave"
superconductivity or the emergence of Majorana modes should be considered
invalid. This version (v2) also includes a brief discussion on the response of
Wang $et$ $al.$ to the first version (v1) of this comment. Correct ballistic
regime data on TaAs point contacts can be found in arXiv:1607.05131 (2016).


title:
Evolution of cosmic filaments and of their galaxy population from MHD
  cosmological simulations

abstract:
  Despite containing about a half of the total matter in the Universe, at most
wavelengths the filamentary structure of the cosmic web is difficult to
observe. In this work, we use large unigrid cosmological simulations to
investigate how the geometrical, thermodynamical and magnetic properties of
cosmological filaments vary with mass and redshift (z $\leq 1$). We find that
the average temperature, length, volume and magnetic field of filaments are
tightly log-log correlated with the underlying total gravitational mass. This
reflects the role of self-gravity in shaping their properties and enables
statistical predictions of their observational properties based on their mass.
We also focus on the properties of the simulated population of galaxy-sized
halos within filaments, and compare their properties to the results obtained
from the spectroscopic GAMA survey. Simulated and observed filaments with the
same length are found to contain an equal number of galaxies, with very similar
distribution of halo masses. The total number of galaxies within each filament
and the total/average stellar mass in galaxies can now be used to predict also
the large-scale properties of the gas in the host filaments across tens or
hundreds of Mpc in scale. These results are the first steps towards the future
use of galaxy catalogues in order to select the best targets for observations
of the warm-hot intergalactic medium.


title: Spider-Web Inspired Mechanical Metamaterials

abstract:
  Spider silk is a remarkable example of bio-material with superior mechanical
characteristics. Its multilevel structural organization of dragline and viscid
silk leads to unusual and tunable properties, extensively studied from a
quasi-static point of view. In this study, inspired by the Nephila spider orb
web architecture, we propose a novel design for mechanical metamaterials based
on its periodic repetition. We demonstrate that spider-web metamaterial
structure plays an important role in the dynamic response and wave attenuation
mechanisms. The capability of the resulting structure to inhibit elastic wave
propagation in sub-wavelength frequency ranges is assessed and parametric
studies are performed to derive optimal configurations and constituent
mechanical properties. The results show promise for the design of innovative
lightweight structures for tunable vibration damping and impact protection, or
the protection of large scale infrastructure such as suspended bridges.


title:
Global and local statistics in turbulent convection at low Prandtl
  numbers

abstract:
  Statistical properties of turbulent Rayleigh-Benard convection at low Prandtl
numbers (Pr), which are typical for liquid metals such as mercury, gallium or
liquid sodium, are investigated in high-resolution three-dimensional spectral
element simulations in a closed cylindrical cell with an aspect ratio of one
and are compared to previous turbulent convection simulations in air. We
compare the scaling of global momentum and heat transfer. The scaling exponents
are found to be in agreement with experiments. Mean profiles of the
root-mean-square velocity as well as the thermal and kinetic energy dissipation
rates have growing amplitudes with decreasing Prandtl number which underlies a
more vigorous bulk turbulence in the low-Pr regime. The skin-friction
coefficient displays a Reynolds-number dependence that is close to that of an
isothermal, intermittently turbulent velocity boundary layer. The thermal
boundary layer thicknesses are larger as Pr decreases and conversely the
velocity boundary layer thicknesses become smaller. We investigate the scaling
exponents and find a slight decrease in exponent magnitude for the thermal
boundary layer thickness as Pr decreases, but find the opposite case for the
velocity boundary layer thickness scaling. A growing area fraction of turbulent
patches close to the heating and cooling plates can be detected by exceeding a
locally defined shear Reynolds number threshold. This area fraction is larger
for lower Pr at the same Ra. Our analysis of the kurtosis of the locally
defined shear Reynolds number demonstrates that the intermittency in the
boundary layer is significantly increased for the lower Prandtl number and for
sufficiently high Rayleigh number compared to convection in air. This
complements our previous findings of enhanced bulk intermittency in
low-Prandtl-number convection.


title: Lorentz invariant CPT breaking in the Dirac equation

abstract:
  If one modifies the Dirac equation in momentum space to
$[\gamma^{\mu}p_{\mu}-m-\Delta m(\theta(p_{0})-\theta(-p_{0}))
\theta(p_{\mu}^{2})]\psi(p)=0$, the symmetry of positive and negative energy
eigenvalues is lifted by $m\pm \Delta m$ for a small $\Delta m$. The mass
degeneracy of the particle and antiparticle is thus lifted in a Lorentz
invariant manner since the combinations $\theta(\pm p_{0})\theta(p_{\mu}^{2})$
with step functions are manifestly Lorentz invariant. We explain an explicit
construction of this CPT breaking term in coordinate space, which is Lorentz
invariant but non-local at a distance scale of the Planck length. The
application of this Lorentz invariant CPT breaking mechanism to the possible
mass splitting of the neutrino and antineutrino in the Standard Model is
briefly discussed.


title:
Special divisors on curves on K3 surfaces carrying an Enriques
  involution

abstract:
  We study the pencils of minimal degree on the smooth curves lying on a K3
surface X which carries a fixed-point free involution. Generically, the
gonality of these curves is totally governed by the genus 1 fibrations of X


title:
The Importance of the Electron Mean Free Path for Superconducting RF
  Cavities

abstract:
  Impurity-doping is an exciting new technology in the field of SRF, producing
cavities with record-high quality factor $Q_0$ and BCS surface resistance that
decreases with increasing RF field. Recent theoretical work has offered a
promising explanation for this anti-Q-slope, but the link between the
decreasing surface resistance and the short mean free path of doped cavities
has remained elusive. In this work we investigate this link, finding that the
magnitude of this decrease varies directly with the mean free path: shorter
mean free paths correspond with stronger anti-Q-slopes. We draw a theoretical
connection between the mean free path and the overheating of the
quasiparticles, which leads to the reduction of the anti-Q-slope towards the
normal Q-slope of long-mean-free-path cavities. We also investigate the
sensitivity of the residual resistance to trapped magnetic flux, a property
which is greatly enhanced for doped cavities, and calculate an optimal doping
regime for a given amount of trapped flux.


title:
Pink's theory of Hodge structures and the Hodge conjecture over function
  fields

abstract:
  In 1997 Richard Pink has clarified the concept of Hodge structures over
function fields in positive characteristic, which today are called Hodge-Pink
structures. They form a neutral Tannakian category over the underlying function
field. He has defined Hodge realization functors from the uniformizable abelian
$t$-modules and $t$-motives of Greg Anderson to Hodge-Pink structures. This
allows one to associate with each uniformizable $t$-motive a Hodge-Pink group,
analogous to the Mumford-Tate group of a smooth projective variety over the
complex numbers. It further enabled Pink to prove the analog of the
Mumford-Tate Conjecture for Drinfeld modules. Moreover, based on unpublished
work of Pink and the first author, the second author proved in her Diploma
thesis that the Hodge-Pink group equals the motivic Galois group of the
$t$-motive as defined by Papanikolas and Taelman. This yields a precise analog
of the famous Hodge Conjecture, which is an outstanding open problem for
varieties over the complex numbers.
  In this report we explain Pink's results on Hodge structures and the proof of
the function field analog of the Hodge conjecture. The theory of $t$-motives
has a variant in the theory of dual $t$-motives. We clarify the relation
between $t$-motives, dual $t$-motives and $t$-modules. We also construct
cohomology realizations of abelian $t$-modules and (dual) $t$-motives and
comparison isomorphisms between them generalizing Gekeler's de Rham isomorphism
for Drinfeld modules.


title:
Analytic functions on the bidisk at boundary singularities via Hilbert
  space methods

abstract:
  We investigate the behavior of a generalized Hilbert space model of a
function in the Schur class of the bidisk at singular boundary points that
satisfy a growth condition. We examine the relationship between the boundary
behavior of Schur functions and the geometry of corresponding generalized
Hilbert space models. We describe a geometric condition on an associated
operator that classifies the behavior of the directional derivative of the
underlying Schur function at a carapoint.


title: Linking in domain-swapped protein dimers

abstract:
  The presence of knots has been observed in a small fraction of single-domain
proteins and related to their thermodynamic and kinetic properties. The
exchanging of identical structural elements, typical of domain-swapped
proteins, make such dimers suitable candidates to validate the possibility that
mutual entanglement between chains may play a similar role for protein
complexes. We suggest that such entanglement is captured by the linking number.
This represents, for two closed curves, the number of times that each curve
winds around the other. We show that closing the curves is not necessary, as a
novel parameter $G'$, termed Gaussian entanglement, is strongly correlated with
the linking number. Based on $110$ non redundant domain-swapped dimers, our
analysis evidences a high fraction of chains with a significant intertwining,
that is with $|G'| > 1$. We report that Nature promotes configurations with
negative mutual entanglement and surprisingly, it seems to suppress
intertwining in long protein dimers. Supported by numerical simulations of
dimer dissociation, our results provide a novel topology-based classification
of protein-swapped dimers together with some preliminary evidence of its impact
on their physical and biological properties.


title:
Fracture of granular materials composed of arbitrary grain shapes: A new
  cohesive interaction model

abstract:
  Discrete Element Methods (DEM) are a useful tool to model the fracture of
cohesive granular materials. For this kind of application, simple particle
shapes (discs in 2D, spheres in 3D) are usually employed. However, dealing with
more general particle shapes allows to account for the natural heterogeneity of
grains inside real materials. We present a discrete model allowing to mimic
cohesion between contacting or non-contacting particles whatever their shape in
2D and 3D. The cohesive interactions are made of cohesion points placed on
interacting particles, with the aim of representing a cohesive phase lying
between the grains. Contact situations are solved according to unilateral
contact and Coulomb friction laws. In order to test the developed model, 2D
unixial compression simulations are performed. Numerical results show the
ability of the model to mimic the macroscopic behavior of an aggregate grain
subject to axial compression, as well as fracture initiation and propagation. A
study of the influence of model and sample parameters provides important
information on the ability of the model to reproduce various behaviors.


title:
Near-Field cosmology with RR Lyrae variable stars: A first view of
  substructure in the southern sky

abstract:
  We present an update of a spectroscopic follow-up survey at low-resolution of
a large number of RR Lyrae halo overdensity candidates found in the southern
sky. The substructure candidates were identified in the RR Lyrae catalog of
Torrealba et al. (2015) using Catalina Real-time Transient Survey (CRTS) data.
Radial velocities and mean metallicities have been estimated for target stars
in almost half of the original overdensities to assess their potential
membership to coherent halo features.


title: Algorithms for Generalized Cluster-wise Linear Regression

abstract:
  Cluster-wise linear regression (CLR), a clustering problem intertwined with
regression, is to find clusters of entities such that the overall sum of
squared errors from regressions performed over these clusters is minimized,
where each cluster may have different variances. We generalize the CLR problem
by allowing each entity to have more than one observation, and refer to it as
generalized CLR. We propose an exact mathematical programming based approach
relying on column generation, a column generation based heuristic algorithm
that clusters predefined groups of entities, a metaheuristic genetic algorithm
with adapted Lloyd's algorithm for K-means clustering, a two-stage approach,
and a modified algorithm of Sp{\"a}th \cite{Spath1979} for solving generalized
CLR. We examine the performance of our algorithms on a stock keeping unit (SKU)
clustering problem employed in forecasting halo and cannibalization effects in
promotions using real-world retail data from a large supermarket chain. In the
SKU clustering problem, the retailer needs to cluster SKUs based on their
seasonal effects in response to promotions. The seasonal effects are the
results of regressions with predictors being promotion mechanisms and seasonal
dummies performed over clusters generated. We compare the performance of all
proposed algorithms for the SKU problem with real-world and synthetic data.


title:
Duffin-Kemmer-Petiau equation in curved space-time with scalar linear
  interactions

abstract:
  In this paper, we study the covariant Duffin-Kemmer-Petiau (DKP) equation in
the space-time generated by a cosmic string and we examine the linear
interaction of a DKP field with gravitational fields produced by topological
defects and thus study the influence of topology on this system. We highlight
two classes of solutions defined by the product of the deficit angle with the
angular velocity of the rotating frame. We solve the covariant form of DKP
equation in an exact analytical manner for node-less and one-node states by
means of an appropriate ansatz.


title: Extended LTLvis Motion Planning interface (Extended Technical Report)

abstract:
  This paper introduces an extended version of the Linear Temporal Logic (LTL)
graphical interface. It is a sketch based interface built on the Android
platform which makes the LTL control interface more straightforward and
friendly to nonexpert users. By predefining a set of areas of interest, this
interface can quickly and efficiently create plans that satisfy extended plan
goals in LTL. The interface can also allow users to customize the paths for
this plan by sketching a set of reference trajectories. Given the custom paths
by the user, the LTL specification and the environment, the interface generates
a plan balancing the customized paths and the LTL specifications. We also show
experimental results with the implemented interface.