title: Cascade photons as test of protons in UHECR

abstract:
  An isotropic component of high energy $\gamma$-ray spectrum measured by Fermi
LAT constrains the proton component of UHECR. The strongest restriction comes
from the highest, $(580-820)$ GeV, energy bin. One more constraint on the
proton component is provided by the IceCube upper bound on ultrahigh energy
cosmogenic neutrino flux. We study the influence of these restrictions on the
source properties, such as evolution and distribution of sources, their energy
spectrum and admixture of nuclei. We also study the sensitivity of restrictions
to various Fermi LAT galactic foreground models (model B being less
restrictive), to the choice of extragalactic background light model and to
overall normalization of the energy spectrum. We claim that the
$\gamma$-ray-cascade constraints are stronger than the neutrino ones, and that
however many proton models are viable. The basic parameters of such models are
relatively large $\gamma_g$ and not very large $z_{\max}$. The allowance for
H$e^4$ admixture also relaxes the restrictions. However we foresee that future
CTA measurements of $\gamma$-ray spectrum at $E_\gamma \simeq (600 - 800)$ GeV,
as well as resolving of more individual $\gamma$-ray sources, may rule out the
proton-dominated cosmic ray models.


title: On dicritical singularities of Levi-flat sets

abstract:
  It is proved that dicritical singularities of real analytic Levi-flat sets
coincide with the set of Segre degenerate points.


title:
Constraining stellar binary black hole formation scenarios with eLISA
  eccentricity measurements

abstract:
  A space-based interferometer such as eLISA could observe few to few thousands
progenitors of black hole binaries (BHBs) similar to those recently detected by
Advanced LIGO. Gravitational radiation circularizes the orbit during inspiral,
but some BHBs retain a measurable eccentricity at the low frequencies where
eLISA is most sensitive. The eccentricity of a BHB carries precious information
about its formation channel: BHBs formed in the field, in globular clusters, or
close to a massive black hole (MBH) have distinct eccentricity distributions in
the eLISA band. We generate mock eLISA observations, folding in measurement
errors, and using Bayesian model selection we study whether eLISA measurements
can identify the BHB formation channel. We find that a handful of observations
would suffice to tell whether BHBs were formed in the gravitational field of a
MBH. Conversely, several tens of observations are needed to tell apart field
formation from globular cluster formation. A five-year eLISA mission with the
longest possible armlength is desirable to shed light on BHB formation
scenarios.


title: How Many Folders Do You Really Need?

abstract:
  Email classification is still a mostly manual task. Consequently, most Web
mail users never define a single folder. Recently however, automatic
classification offering the same categories to all users has started to appear
in some Web mail clients, such as AOL or Gmail. We adopt this approach, rather
than previous (unsuccessful) personalized approaches because of the change in
the nature of consumer email traffic, which is now dominated by (non-spam)
machine-generated email. We propose here a novel approach for (1) automatically
distinguishing between personal and machine-generated email and (2) classifying
messages into latent categories, without requiring users to have defined any
folder. We report how we have discovered that a set of 6 "latent" categories
(one for human- and the others for machine-generated messages) can explain a
significant portion of email traffic. We describe in details the steps involved
in building a Web-scale email categorization system, from the collection of
ground-truth labels, the selection of features to the training of models.
Experimental evaluation was performed on more than 500 billion messages
received during a period of six months by users of Yahoo mail service, who
elected to be part of such research studies. Our system achieved precision and
recall rates close to 90% and the latent categories we discovered were shown to
cover 70% of both email traffic and email search queries. We believe that these
results pave the way for a change of approach in the Web mail industry, and
could support the invention of new large-scale email discovery paradigms that
had not been possible before.


title: Entropic and Near-Field Improvements of Thermoradiative Cells

abstract:
  A p-n junction maintained at above ambient temperature can work as a heat
engine, converting some of the supplied heat into electricity and rejecting
entropy by interband emission. Such thermoradiative cells have potential to
harvest low-grade heat into electricity. By analyzing the entropy content of
different spectral components of thermal radiation, we identify an approach to
increase the efficiency of thermoradiative cells via spectrally selecting
long-wavelength photons for radiative exchange. Furthermore, we predict that
the near-field photon extraction by coupling photons generated from interband
electronic transition to phonon polariton modes on the surface of a heat sink
can increase the conversion efficiency as well as the power generation density,
providing more opportunities to efficiently utilize terrestrial emission for
clean energy. An ideal InSb thermoradiative cell can achieve a maximum
efficiency and power density up to 20.4 % and 327 Wm-2, respectively, between a
hot source at 500K and a cold sink at 300K. However, sub-bandgap and
non-radiative losses will significantly degrade the cell performance.


title:
Distributed coordination for nonsmooth convex optimization via
  saddle-point dynamics

abstract:
  This paper considers continuous-time coordination algorithms for networks of
agents that seek to collectively solve a general class of nonsmooth convex
optimization problems with an inherent distributed structure. Our algorithm
design builds on the characterization of the solutions of the nonsmooth convex
program as saddle points of an augmented Lagrangian. We show that the
associated saddle-point dynamics are asymptotically correct but, in general,
not distributed because of the presence of a global penalty parameter. This
motivates the design of a discontinuous saddle-point-like algorithm that enjoys
the same convergence properties and is fully amenable to distributed
implementation. Our convergence proofs rely on the identification of a novel
global Lyapunov function for saddle-point dynamics. This novelty also allows us
to identify mild convexity and regularity conditions on the objective function
that guarantee the exponential convergence rate of the proposed algorithms for
convex optimization problems subject to equality constraints. Various examples
illustrate our discussion.


title: Counting Matrices that are Squares

abstract:
  On the math-fun mailing list (7 May 2013), Neil Sloane asked to calculate the
number of $n \times n$ matrices with entries in $\{0,1\}$ which are squares of
other such matrices. In this paper we analyze the case that the arithmetic is
in $\mathbb{F}_{2}$. We follow the dictum of Wilf ("What is an answer?") to
derive a "effective" algorithm to count such matrices in much less time than it
takes to enumerate them. The algorithm which we use involves the analysis of
conjugacy classes of matrices. The restricted integer partitions which arise
are counted by the coefficients of one of Ramanujan's mock Theta functions,
which we found thanks to Sloane's OEIS (Online Encyclopedia of Integer
Sequences). Let $a_n$ be the number elements of ${\rm Mat}_n(\mathbb{F}_{2})$
which are squares, and $b_n$ be the number of elements of ${\rm
GL}(n,\mathbb{F}_{2})$ which are squares. The numerical results strongly
suggest that there are constants $\alpha,\beta > 0$ such that $a_n \sim \alpha
2^{n^2}$, $b_n \sim \beta 2^{n^2}$.


title:
Semileptonic $B_{(s)}$ decays to excited charmed mesons with
  $e,\mu,\tau$ and searching for new physics with $R(D^{**})$

abstract:
  Semileptonic $B$ meson decays into the four lightest excited charmed meson
states ($D_0^*$, $D_1^*$, $D_1$, and $D_2^*$) and their counterparts with $s$
quarks are investigated, including the full lepton mass dependence. We derive
the standard model predictions for the differential branching fractions, as
well as predictions for the ratios of the semi-tauonic and light lepton
semileptonic branching fractions. These can be systematically improved using
future measurements of the total or differential semileptonic rates to $e$ and
$\mu$, as well as the two-body hadronic branching fractions with a pion,
related by factorization to the semileptonic rate at maximal recoil. To
illustrate the different sensitivities to new physics, we explore the
dependence of the ratio of semi-tauonic and light-lepton branching fractions on
the type-II and type-III two-Higgs-doublet model parameters, $\tan\beta$ and
$m_{H}^\pm$, for all four states.


title: Hyperelliptic genus 4 curves on abelian surfaces

abstract:
  We study smooth curves on abelian surfaces, especially for genus 4, when the
complementary subvariety in the Jacobian is also a surface. We show that up to
translation there is exactly one genus 4 hyperelliptic curve on a general (1,
3)-polarised abelian surface. We investigate these curves and show that their
Jacobians contain a surface and its dual as complementary abelian subvarieties.


title:
The Hydrodynamic Scaling Model for the Dynamics of Non-Dilute Polymer
  Solutions: A Comprehensive Review

abstract:
  This article presents a comprehensive review of the Hydrodynamic Scaling
Model for the dynamics of polymers in dilute and nondilute solutions. The
Hydrodynamic Scaling Model differs from some other treatments of non-dilute
polymer solutions in that it takes polymer dynamics up to high concentrations
to be dominated by solvent-mediated hydrodynamic interactions, with chain
crossing constraints presumed to create at most secondary corrections. Many
other models take the contrary stand, namely that chain crossing constraints
dominate the dynamics of nondilute polymer solutions, while hydrodynamic
interactions only create secondary corrections. This article begins with a
historical review. We then consider single-chain behavior, in particular the
Kirkwood-Riseman model; contradictions between the Kirkwood-Riseman and more
familiar Rouse-Zimm models are emphasized. An extended Kirkwood-Riseman model
that gives interchain hydrodynamic interactions is developed and applied to
generate pseudovirial series for the self-diffusion coefficient and the
low-shear viscosity. To extrapolate to large concentrations, rationales based
on self-similarity and on the Altenberger-Dahler Positive-Function
Renormalization Group are developed and applied to the pseudovirial series for
$D_{s}$ and $\eta$. Based on the renormalization group method, a two-parameter
temporal scaling ansatz is invoked as a path to determining the frequency
dependences of the storage and loss moduli. A short description is given for
each of the individual papers that developed the Hydrodynamic Scaling Model.
Phenomenological evidence supporting aspects of the model is noted. Finally,
directions for future development of the Hydrodynamic Scaling Model are
presented.


title: The abelian arithmetic regularity lemma

abstract:
  We give a brief exposition and proof of the arithmetic regularity lemma of
Green and Tao in the abelian ($U^2$) case, over $\{1,\dots,N\}$. This may be
useful to those who need just the $U^2$ case of the lemma, as the general case
is significantly more involved. It may also be useful as an introduction to the
general case. No originality is claimed.


title:
Supersymmetric Backgrounds, the Killing Superalgebra, and Generalised
  Special Holonomy

abstract:
  We prove that, for M theory or type II, generic Minkowski flux backgrounds
preserving $\mathcal{N}$ supersymmetries in dimensions $D\geq4$ correspond
precisely to integrable generalised $G_{\mathcal{N}}$ structures, where
$G_{\mathcal{N}}$ is the generalised structure group defined by the Killing
spinors. In other words, they are the analogues of special holonomy manifolds
in $E_{d(d)} \times\mathbb{R}^+$ generalised geometry. In establishing this
result, we introduce the Kosmann-Dorfman bracket, a generalisation of Kosmann's
Lie derivative of spinors. This allows us to write down the internal sector of
the Killing superalgebra, which takes a rather simple form and whose closure is
the key step in proving the main result. In addition, we find that the
eleven-dimensional Killing superalgebra of these backgrounds is necessarily the
supertranslational part of the $\mathcal{N}$-extended super-Poincar\'e algebra.


title:
Experimental Study of Nonlinear Resonances and Anti-resonances in a
  Forced, Ordered Granular Chain

abstract:
  We experimentally study a one-dimensional uncompressed granular chain
composed of a finite number of identical spherical beads with Hertzian
interactions. The chain is harmonically excited by an amplitude- and
frequency-dependent boundary drive at its left end and has a fixed boundary at
its right end. Such ordered granular media represent an interesting new class
of nonlinear acoustic metamaterials, since they exhibit essentially nonlinear
acoustics and have been designated as 'sonic vacua' due to the fact that their
corresponding speed of sound (as defined in classical acoustics) is zero.This
paves the way for essentially nonlinear and energy-dependent acoustics with no
counterparts in linear theory. We experimentally detect time-periodic, strongly
nonlinear resonances whereby the particles (beads) of the granular chain
respond at integer multiples of the excitation period, and which correspond to
local peaks of the maximum transmitted force at the chain's right, fixed end.In
between these resonances we detect a local minimum of the maximum transmitted
forces corresponding to an anti-resonance in the stationary-state dynamics. The
experimental results of this work confirm previous theoretical predictions, and
verify the existence of strongly nonlinear resonance responses in a system with
a complete absence of any linear spectrum; as such, the experimentally detected
nonlinear resonance spectrum is passively tunable with energy and sensitive to
dissipative effects such as internal structural damping in the beads, and
friction or plasticity effects. The experimental results are verified by direct
numerical simulations and by numerical stability analysis.


title: A Royal Road to Quantum Theory (or Thereabouts)

abstract:
  This paper fails to derive quantum mechanics from a few simple postulates.
But it gets very close --- and it does so without much exertion. More exactly,
I obtain a representation of finite-dimensional probabilistic systems in terms
of euclidean Jordan algebras, in a strikingly easy way, from simple
assumptions. This provides a framework within which real, complex and
quaternionic QM can play happily together, and allows some --- but not too much
--- room for more exotic alternatives. (This is a leisurely summary, based on
recent lectures, of material from the papers arXiv:1206:2897 and
arXiv:1507.06278, the latter joint work with Howard Barnum and Matthew Graydon.
Some further ideas are also explored.)


title: The rotation curve of a point particle in stringy gravity

abstract:
  Double Field Theory suggests to view the whole massless sector of closed
strings as the gravitational unity. The fundamental symmetries therein,
including the $\mathbf{O}(D,D)$ covariance, can determine unambiguously how the
Standard Model as well as a relativistic point particle should couple to the
closed string massless sector. The theory also refines the notion of
singularity. We consider the most general, spherically symmetric,
asymptotically flat, static vacuum solution to ${D=4}$ Double Field Theory,
which contains three free parameters and consequently generalizes the
Schwarzschild geometry. Analyzing the circular geodesic of a point particle in
string frame, we obtain the orbital velocity as a function of
$R/(M_{\scriptscriptstyle{\infty}}G)$ which is the dimensionless radial
variable normalized by mass. The rotation curve generically features a maximum
and thus non-Keplerian over a finite range, while becoming asymptotically
Keplerian at infinity, $R/(M_{\scriptscriptstyle{\infty}}G)\rightarrow \infty$.
The adoption of the string frame rather than Einstein frame is the consequence
of the fundamental symmetry principle. Our result opens up a new scheme to
solve the dark matter/energy problems by modifying General Relativity at
`short' range of $R/(M_{\scriptscriptstyle{\infty}}G)$.


title:
Monitoring communication outbreaks among an unknown team of actors in
  dynamic networks

abstract:
  This paper investigates the detection of communication outbreaks among a
small team of actors in time-varying networks. We propose monitoring plans for
known and unknown teams based on generalizations of the exponentially weighted
moving average (EWMA) statistic. For unknown teams, we propose an efficient
neighborhood-based search to estimate a collection of candidate teams. This
procedure dramatically reduces the computational complexity of an exhaustive
search. Our procedure consists of two steps: communication counts between
actors are first smoothed using a multivariate EWMA strategy. Densely connected
teams are identified as candidates using a neighborhood search approach. These
candidate teams are then monitored using a surveillance plan derived from a
generalized EWMA statistic. Monitoring plans are established for collaborative
teams, teams with a dominant leader, as well as for global outbreaks. We
consider weighted heterogeneous dynamic networks, where the expected
communication count between each pair of actors is potentially different across
pairs and time, as well as homogeneous networks, where the expected
communication count is constant across time and actors. Our monitoring plans
are evaluated on a test bed of simulated networks as well as on the U.S. Senate
co-voting network, which models the Senate voting patterns from 1857 to 2015.
Our analysis suggests that our surveillance strategies can efficiently detect
relevant and significant changes in dynamic networks.


title:
New Behavior in Legal Decompositions Arising from Non-positive Linear
  Recurrences

abstract:
  Zeckendorf's theorem states every positive integer has a unique decomposition
as a sum of non-adjacent Fibonacci numbers. This result has been generalized to
many sequences $\{a_n\}$ arising from an integer positive linear recurrence,
each of which has a corresponding notion of a legal decomposition. Previous
work proved the number of summands in decompositions of $m \in [a_n, a_{n+1})$
becomes normally distributed as $n\to\infty$, and the individual gap measures
associated to each $m$ converge to geometric random variables, when the leading
coefficient in the recurrence is positive. We explore what happens when this
assumption is removed in two special sequences. In one we regain all previous
results, including unique decomposition; in the other the number of legal
decompositions exponentially grows and the natural choice for the legal
decomposition (the greedy algorithm) only works approximately 92.6\% of the
time (though a slight modification always works). We find a connection between
the two sequences, which explains why the distribution of the number of
summands and gaps between summands behave the same in the two examples. In the
course of our investigations we found a new perspective on dealing with roots
of polynomials associated to the characteristic polynomials. This allows us to
remove the need for the detailed technical analysis of their properties which
greatly complicated the proofs of many earlier results in the subject, as well
as handle new cases beyond the reach of existing techniques.


title:
Phase-referenced Nonlinear Spectroscopy of the alpha-Quartz/Water
  Interface

abstract:
  Probing the polarization of water molecules at charged interfaces by second
harmonic generation spectroscopy has been heretofore limited to isotropic
materials. Here, we report non-resonant nonlinear optical measurements at the
interface of anisotropic z-cut {\alpha}-quartz and water under conditions of
dynamically changing ionic strength and bulk solution pH. We find that the
product of the third-order susceptibility and the interfacial potential,
\c{hi}(3). {\Phi}(0), is given by ( \c{hi}(3)-i\c{hi}(3)). {\Phi}(0), and that
the interference between this product and the second-order susceptibility of
bulk quartz depends on the rotation angle of {\alpha}-quartz around the z-axis.
Our experiments show that this newly identified term, i\c{hi}(3). {\Phi}(0),
which is out of phase from the surface terms, is of bulk origin. The
possibility of internally phase referencing the interfacial response for the
interfacial orientation analysis of species or materials in contact with
{\alpha}-quartz is discussed along with the implications for conditions of
resonance enhancement.


title:
Electron-hole doping asymmetry of Fermi surface reconstructed in a
  simple Mott insulator

abstract:
  It is widely recognised that the effect of doping into a Mott insulator is
complicated and unpredictable, as can be seen by examining the Hall coefficient
in high $T_{\rm c}$ cuprates. The doping effect, including the electron-hole
doping asymmetry, may be more straightforward in doped organic Mott insulators
owing to their simple electronic structures. Here we investigate the doping
asymmetry of an organic Mott insulator by carrying out electric-double-layer
transistor measurements and using cluster perturbation theory. The calculations
predict that strongly anisotropic suppression of the spectral weight results in
the Fermi arc state under hole doping, while a relatively uniform spectral
weight results in the emergence of a non-interacting-like Fermi surface in the
electron-doped state. In accordance with the calculations, the experimentally
observed Hall coefficients and resistivity anisotropy correspond to the pocket
formed by the Fermi arcs under hole doping and to the non-interacting Fermi
surface under electron doping.


title: Legal Decompositions Arising from Non-positive Linear Recurrences

abstract:
  Zeckendorf's theorem states that any positive integer can be written uniquely
as a sum of non-adjacent Fibonacci numbers; this result has been generalized to
many recurrence relations, especially those arising from linear recurrences
with leading term positive. We investigate legal decompositions arising from
two new sequences: the $(s,b)$-Generacci sequence and the Fibonacci Quilt
sequence. Both satisfy recurrence relations with leading term zero, and thus
previous results and techniques do not apply. These sequences exhibit
drastically different behavior. We show that the $(s,b)$-Generacci sequence
leads to unique legal decompositions, whereas not only do we have non-unique
legal decompositions with the Fibonacci Quilt sequence, we also have that in
this case the average number of legal decompositions grows exponentially.
Another interesting difference is that while in the $(s,b)$-Generacci case the
greedy algorithm always leads to a legal decomposition, in the Fibonacci Quilt
setting the greedy algorithm leads to a legal decomposition (approximately)
93\% of the time. In the $(s,b)$-Generacci case, we again have Gaussian
behavior in the number of summands as well as for the Fibonacci Quilt sequence
when we restrict to decompositions resulting from a modified greedy algorithm.


title: Generic Local Hamiltonians are Gapless

abstract:
  We prove that generic quantum local Hamiltonians are gapless. In fact, we
prove that there is a continuous density of states above the ground state. The
Hamiltonian can be on a lattice in any spatial dimension or on a graph with a
bounded maximum vertex degree. The type of interactions allowed for include
translational invariance in a disorder (i.e., probabilistic) sense with some
assumptions on the local distributions. Examples include many-body localization
and random spin models. We calculate the scaling of the gap with the system's
size when the local terms are distributed according to a Gaussian
$\beta-$orthogonal random matrix ensemble. As a corollary there exist finite
size partitions with respect to which the ground state is arbitrarily close to
a product state. When the local eigenvalue distribution is discrete, in
addition to the lack of an energy gap in the limit, we prove that the ground
state has finite size degeneracies. The proofs are simple and constructive.
This work excludes the important class of truly translationally invariant
Hamiltonians where the local terms are all equal.

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


title:
Entanglement-assisted classical capacities of compound and arbitrarily
  varying quantum channels

abstract:
  We consider classical message transmission under entanglement assistance for
compound memoryless and arbitrarily varying quantum channels. In both cases, we
prove general coding theorems together with corresponding weak converse bounds.
In this way, we obtain single-letter characterizations of the
entanglement-assisted classical capacities for both channel models. Moreover,
we show that the entanglement-assisted classical capacity does exhibit no
strong converse property for some compound quantum channels for the average as
well as the maximal error criterion. A strong converse to the
entanglement-assisted classical capacities does hold for each arbitrarily
varying quantum channel.


title:
Data Compression for Analytics over Large-scale In-memory Column
  Databases

abstract:
  Data compression schemes have exhibited their importance in column databases
by contributing to the high-performance OLAP (Online Analytical Processing)
query processing. Existing works mainly concentrate on evaluating compression
schemes for disk-resident databases as data is mostly stored on disks. With the
continuously decreasing of the price/capacity ratio of main memory, it is the
tendencies of the times to reside data in main memory. But the discussion of
data compression on in-memory databases is very vague in the literature. In
this work, we present an updated discussion about whether it is valuable to use
data compression techniques in memory databases. If yes, how should memory
databases apply data compression schemes to maximize performance?


title: Supernovae powered by magnetars that transform into black holes

abstract:
  Rapidly rotating, strongly magnetized neutron stars (magnetars) can release
their enormous rotational energy via magnetic spin-down, providing a power
source for bright transients such as superluminous supernovae. On the other
hand, particularly massive (so-called supramassive) neutron stars require a
minimum rotation rate to support their mass against gravitational collapse,
below which the neutron star collapses to a black hole. We model the light
curves of supernovae powered by magnetars which transform into black holes.
Although the peak luminosities can reach high values in the range of
superluminous supernovae, their post maximum light curves can decline very
rapidly because of the sudden loss of the central energy input. Early black
hole transformation also enhances the shock breakout signal from the
magnetar-driven bubble relative to the main supernova peak. Our synthetic light
curves of supernovae powered by magnetars transforming to black holes are
consistent with those of some rapidly evolving bright transients recently
reported by Arcavi et al. (2016).


title: Right-handed neutrino dark matter under the B-L gauge interaction

abstract:
  We study the right-handed neutrino (RHN) dark matter candidate in the minimal
U(1)_{B-L} gauge extension of the standard model. The U(1)_{B-L} gauge symmetry
offers three RHNs which can address the origin of the neutrino mass, the relic
dark matter, and the matter-antimatter asymmetry of the universe. The lightest
among the three is taken as the dark matter candidate, which is under the B-L
gauge interaction. We investigate various scenarios for this dark matter
candidate with the correct relic density by means of the freeze-out or
freeze-in mechanism. A viable RHN dark matter mass lies in a wide range
including keV to TeV scale. We emphasize the sub-electroweak scale light B-L
gauge boson case, and identify the parameter region motivated from the dark
matter physics, which can be tested with the planned experiments including the
CERN SHiP experiment.


title:
The odd-isotope fractions of Barium in CEMP-r/s star HE 0338-3945 and
  r-II star CS 31082-001

abstract:
  We report the first measurement of the odd-isotope fractions for barium,
\fodd\, in two extremely metal-poor stars: a CEMP-r/s star \he\
(\feh\,$=-2.42\pm0.11$) and an r-II star \cs\ (\feh\,$=-2.90\pm0.13$). The
measured \fodd\ values are $0.23\pm0.12$ corresponding to $34.3\pm34.3$\% of
the r-process contributions for \he\ and $0.43\pm0.09$ corresponding to
$91.4\pm25.7$\% of the r-process contribution to Ba production for \cs. The
high r-process signature of barium in \cs\ ($91.4\pm25.7\%$) suggests that the
majority of the heavy elements in this star were synthesised via an r-process
path, while the lower r-process value ($34.3\pm34.3\%$) found in \he\ indicates
that the heavy elements in this star formed through a mix of s-process and
r-process synthesis. These conclusions are consistent with studies based on AGB
model calculations to fit their abundance distributions.


title: Reduced Order Podolsky Model

abstract:
  We perform the canonical and path integral quantizations of a lower-order
derivatives model describing Podolsky's generalized electrodynamics. The
physical content of the model shows an auxiliary massive vector field coupled
to the usual electromagnetic field. The equivalence with Podolsky's original
model is studied at classical and quantum levels. Concerning the dynamical time
evolution we obtain a theory with two first-class and two second-class
constraints in phase space. We calculate explicitly the corresponding Dirac
brackets involving both vector fields. We use the Senjanovic procedure to
implement the second-class constraints and the Batalin-Fradkin-Vilkovisky path
integral quantization scheme to deal with the symmetries generated by the
first-class constraints. The physical interpretation of the results turns out
to be simpler due to the reduced derivatives order permeating the equations of
motion, Dirac brackets and effective action.


title: Class numbers of large degree nonabelian number fields

abstract:
  If a number field has a large degree and discriminant, the computation of the
class number becomes quite difficult, especially without the assumption of GRH.
In this article, we will unconditionally show that a certain nonabelian number
field of degree 120 has class number one. This field is the unique $A_5 \times
C_2$ extension of the rationals that is ramified only at 653 with ramification
index 2. It is the largest degree number field unconditionally proven to have
class number 1.
  The proof uses the algorithm of Gu\`ardia, Montes and Nart to calculate an
integral basis and then finds integral elements of small prime power norm to
establish an upper bound for the class number; further algebraic arguments
prove the class number is 1. It is possible to apply these techniques to other
nonabelian number fields as well.


title: Performance of Ensemble Kalman filters in large dimensions

abstract:
  Contemporary data assimilation often involves more than a million prediction
variables. Ensemble Kalman filters (EnKF) have been developed by geoscientists.
They are successful indispensable tools in science and engineering, because
they allow for computationally cheap low ensemble state approximation for
extremely large dimensional turbulent dynamical systems. The practical finite
ensemble filter like EnKF necessarily involve modifications such as covariance
inflation and localization, and it is a genuine mystery why they perform so
well with small ensemble sizes in large dimensions. This paper provides the
first rigorous stochastic analysis of the accuracy and covariance fidelity of
EnKF in the practical regime where the ensemble size is much smaller than the
large ambient dimension for EnKFs with random coefficients. A challenging issue
overcome here is that EnKF in huge dimensions introduces unavoidable bias and
model errors which need to be controlled and estimated.


title: Flux rope proxies and fan-spine structures in active region NOAA 11897

abstract:
  Employing the high-resolution observations from the Solar Dynamics
Observatory (SDO) and the Interface Region Imaging Spectrograph (IRIS), we
statistically investigate flux rope proxies in NOAA AR 11897 from 14-Nov-2013
to 19-Nov-2013 and display two fan-spine structures in this AR. For the first
time, we detect flux rope proxies of NOAA 11897 for total 30 times in 4
different locations. These flux rope proxies were either tracked in both lower
and higher temperature wavelengths or only detected in hot channels. Specially,
none of these flux rope proxies was observed to erupt, but just faded away
gradually. In addition to these flux rope proxies, we firstly detect a
secondary fan-spine structure. It was covered by dome-shaped magnetic fields
which belong to a larger fan-spine topology. These new observations imply that
considerable amounts of flux ropes can exist in an AR and the complexity of AR
magnetic configuration is far beyond our imagination.


title:
Optical rogue waves and W-shaped solitons in the multiple self-induced
  transparency system

abstract:
  We study localized nonlinear waves on a plane wave background in the multiple
self-induced transparency (SIT) system, which describes an important
enhancement of the amplification and control of optical waves compared to the
single SIT system. A hierarchy of exact multiparametric rational solutions in a
compact determinant representation are presented. We demonstrate that, this
family of solutions contains known rogue wave solution and unusual W-shaped
soliton solution, which strictly corresponds to the linear stability analysis
that involves modulation instability and stability regimes in the low
perturbation frequency region. State transitions between rogue waves and
W-shaped solitons as well as the higher-order nonlinear superposition modes are
revealed by the suitable choice for the background wavenumber of electric field
component. In particular, our results show that, the multiple SIT system admits
stationary and nonstationary nonlinear modes in contrast to the results in the
single SIT system. Correspondingly, the important characteristics of the
nonlinear waves including trajectories and spectrum are revealed in detail.


title: Asteroseismology of the $\delta$ Scuti star HD 50844

abstract:
  Aims. We aim to probe the internal structure and investigate more detailed
information of the $\delta$ Scuti star HD 50844 with asteroseismology. Methods.
We analyse the observed frequencies of the $\delta$ Scuti star HD 50844
obtained by Balona (2014), and search for possible multiplets based on the
rotational splitting law of g-mode. We tried to disentangle the frequency
spectra of HD 50844 by means of the rotational splitting only. We then compare
them with theoretical pulsation modes, which correspond to stellar evolutionary
models with various sets of initial metallicity and stellar mass, to find the
best-fitting model. Results. There are three multiplets including two complete
triplets and one incomplete quintuplet, in which mode identifications for
spherical harmonic degree $l$ and azimuthal number $m$ are unique. The
corresponding rotational period of HD 50844 is found to be
2.44$^{+0.13}_{-0.08}$ days. The physical parameters of HD 50844 are well
limited in a small region by three modes identified as nonradial ones
($f_{11}$, $f_{22}$, and $f_{29}$) and by the fundamental radial mode
($f_{4}$). Our results show that the three nonradial modes ($f_{11}$, $f_{22}$,
and $f_{29}$) are all mixed modes, which mainly represent the property of the
helium core. The fundamental radial mode ($f_{4}$) mainly represents the
property of the stellar envelope. In order to fit these four pulsation modes,
both the helium core and the stellar envelope must be matched to the actual
structure of HD 50844. Finally, the mass of the helium core of HD 50844 is
estimated to be 0.173 $\pm$ 0.004 $M_{\odot}$ for the first time. The physical
parameters of HD 50844 are determined to be $M=$ 1.81 $\pm$ 0.01 $M_{\odot}$,
$Z=$ 0.008 $\pm$ 0.001. $T_{\rm eff}=$ 7508 $\pm$ 125 K, log$g=$ 3.658 $\pm$
0.004, $R=$ 3.300 $\pm$ 0.023 $R_{\odot}$, $L=$ 30.98 $\pm$ 2.39 $L_{\odot}$.


title:
Search for Perturbations of Nuclear Decay Rates Induced by Reactor
  Electron Antineutrinos

abstract:
  We report the results of an experiment conducted near the High Flux Isotope
Reactor of Oak Ridge National Laboratory, designed to address the question of
whether a flux of reactor-generated electron antineutrinos can alter the rates
of weak nuclear interaction-induced decays for Mn-54, Na-22, and Co-60. This
experiment, while quite sensitive, cannot exclude perturbations less than one
or two parts in $10^4$ in $\beta$ decay (or electron capture) processes, in the
presence of an antineutrino flux of $3\times 10^{12}$ cm$^{-2}$ s$^{-1}$. The
present experimental methods are applicable to a wide range of isotopes.
Improved sensitivity in future experiments may be possible if we can understand
and reduce the dominant systematic uncertainties.


title:
Skyrmion dynamics in a chiral magnet driven by periodically varying spin
  currents

abstract:
  In this work, we investigated the spin dynamics in a slab of chiral magnets
induced by an alternating (ac) spin current. Periodic trajectories of the
skyrmion in real space are discovered under the ac current as a result of the
Magnus and viscous forces, which originate from the Gilbert damping, the spin
transfer torque, and the $ \beta $-nonadiabatic torque effects. The results are
obtained by numerically solving the Landau-Lifshitz-Gilbert equation and can be
explained by the Thiele equation characterizing the skyrmion core motion.


title:
Far-field nanoscale infrared spectroscopy of vibrational fingerprints of
  molecules with graphene plasmons

abstract:
  Infrared spectroscopy, especially for molecular vibrations in the fingerprint
region between 600 and 1500 cm-1, is a powerful characterization method for
bulk materials. However, molecular fingerprinting at the nanoscale level still
remains a significant challenge, due to weak light-matter interaction between
micron-wavelengthed infrared light and nano-sized molecules. Here, we
demonstrate molecular fingerprinting at the nanoscale level using our specially
designed graphene plasmonic structure on CaF2 nanofilm. This structure not only
avoids the plasmon-phonon hybridization, but also provides in situ
electrically-tunable graphene plasmon covering the entire infrared fingerprint
region, which was previously unattainable. In addition, undisturbed and
highly-confined graphene plasmon offers simultaneous detection of in-plane and
out-of-plane vibrational modes with ultrahigh detection sensitivity down to the
sub-monolayer level, significantly pushing the current detection limit of
far-field mid-infrared spectroscopy. Our results provide a platform, fulfilling
the long-awaited expectation of high sensitivity and selectivity far-field
fingerprint detection of nano-scale molecules for numerous applications.


title:
Lipschitz type, radial growth and Dirichlet type spaces on functions
  induced by certain elliptic operators

abstract:
  In this paper, we investigate properties of classes of functions related to
certain elliptic operators. Firstly, we prove that a main result of Dyakonov
(Acta Math. 178(1997), 143--167) on analytic functions can be extended to this
more general setting. Secondly, we study the radial growth on these functions
and the obtained results are generalizations of the corresponding results of
Makarov (Proc. London Math. Soc. 51(1985), 369--384) and Korenblum (Bull. Amer.
Math. Soc. 12(1985), 99--102). Finally, we discuss the Dirichlet type energy
integrals on such classes of functions and their applications.


title:
Distributed Average Tracking for Multiple Signals Generated by Linear
  Dynamical Systems: An Edge-based Framework

abstract:
  This paper studies the distributed average tracking problem for multiple
time-varying signals generated by linear dynamics, whose reference inputs are
nonzero and not available to any agent in the network. In the edge-based
framework, a pair of continuous algorithms with, respectively, static and
adaptive coupling strengths are designed. Based on the boundary layer concept,
the proposed continuous algorithm with static coupling strengths can
asymptotically track the average of multiple reference signals without the
chattering phenomenon. Furthermore, for the case of algorithms with adaptive
coupling strengths, average tracking errors are uniformly ultimately bounded
and exponentially converge to a small adjustable bounded set. Finally, a
simulation example is presented to show the validity of theoretical results.


title: New neutron-rich isotope production in $^{154}$Sm+$^{160}$Gd

abstract:
  Deep inelastic scattering in $^{154}$Sm+$^{160}$Gd at energies above the Bass
barrier is for the first time investigated with two different microscopic
dynamics approaches: improved quantum molecular dynamics (ImQMD) model and time
dependent Hartree-Fock (TDHF) theory. No fusion is observed from both models.
The capture pocket disappears for this reaction due to strong Coulomb repulsion
and the contact time of the di-nuclear system formed in head-on collisions is
about 700 fm/c at an incident energy of 440 MeV. The isotope distribution of
fragments in the deep inelastic scattering process is predicted with the
simulations of the latest ImQMD-v2.2 model together with a statistical code
(GEMINI) for describing the secondary decay of fragments. More than 40
extremely neutron-rich unmeasured nuclei with $58 \le Z\le 76$ are observed and
the production cross sections are at the order of ${\rm \mu b}$ to mb. The
multi-nucleon transfer reaction of Sm+Gd could be an alternative way to
synthesize new neutron-rich lanthanides which are difficult to be produced with
traditional fusion reactions or fission of actinides.


title: Composites and Categories of Euclidean Jordan Algebras

abstract:
  We consider possible non-signaling composites of probabilistic models based
on euclidean Jordan algebras (EJAs), satisfying some reasonable additional
constraints motivated by the desire to construct dagger-compact categories of
such models. We show that no such composite has the exceptional Jordan algebra
as a direct summand, nor does any such composite exist if one factor has an
exceptional summand, unless the other factor is a direct sum of one-dimensional
Jordan algebras (representing essentially a classical system). Moreover, we
show that any composite of simple, non-exceptional EJAs is a direct summand of
their universal tensor product, sharply limiting the possibilities.
  These results warrant our focussing on concrete Jordan algebras of hermitian
matrices, i.e., euclidean Jordan algebras with a preferred embedding in a
complex matrix algebra}. We show that these can be organized in a natural way
as a symmetric monoidal category, albeit one that is not compact closed. We
then construct a related category InvQM of embedded euclidean Jordan algebras,
having fewer objects but more morphisms, that is not only compact closed but
dagger-compact. This category unifies finite-dimensional real, complex and
quaternionic mixed-state quantum mechanics, except that the composite of two
complex quantum systems comes with an extra classical bit.
  Our notion of composite requires neither tomographic locality, nor
preservation of purity under tensor product. The categories we construct
include examples in which both of these conditions fail. In such cases, the
information capacity (the maximum number of mutually distinguishable states) of
a composite is greater than the product of the capacities of its constituents.


title: Spatiotemporal accessible solitons in fractional dimensions

abstract:
  We report solutions for solitons of the "accessible" type in globally
nonlocal nonlinear media of fractional dimension (FD), viz., for self-trapped
modes in the space of effective dimension $2<D\le3$ with harmonic-oscillator
potential whose strength is proportional to the total power of the wave field.
The solutions are categorized by a combination of radial, orbital and azimuthal
quantum numbers $(n,l,m)$. They feature coaxial sets of vortical and
necklace-shaped rings of different orders, and can be exactly written in terms
of special functions that include Gegenbauer polynomials, associated Laguerre
polynomials, and associated Legendre functions. The validity of these solutions
is verified by direct simulation. The model can be realized in various physical
settings emulated by FD spaces; in particular, it applies to excitons trapped
in quantum wells.


title: Dimension-Free Iteration Complexity of Finite Sum Optimization Problems

abstract:
  Many canonical machine learning problems boil down to a convex optimization
problem with a finite sum structure. However, whereas much progress has been
made in developing faster algorithms for this setting, the inherent limitations
of these problems are not satisfactorily addressed by existing lower bounds.
Indeed, current bounds focus on first-order optimization algorithms, and only
apply in the often unrealistic regime where the number of iterations is less
than $\mathcal{O}(d/n)$ (where $d$ is the dimension and $n$ is the number of
samples). In this work, we extend the framework of (Arjevani et al., 2015) to
provide new lower bounds, which are dimension-free, and go beyond the
assumptions of current bounds, thereby covering standard finite sum
optimization methods, e.g., SAG, SAGA, SVRG, SDCA without duality, as well as
stochastic coordinate-descent methods, such as SDCA and accelerated proximal
SDCA.


title: How did a Major Confined Flare Occur in Super Solar Active Region 12192?

abstract:
  We study the physical mechanism of a major X-class solar flare that occurred
in the super NOAA active region (AR) 12192 using a data-driven numerical
magnetohydrodynamic (MHD) modeling complemented with observations. With the
evolving magnetic fields observed at the solar surface as bottom boundary
input, we drive an MHD system to evolve self-consistently in correspondence
with the realistic coronal evolution. During a two-day time interval, the
modeled coronal field has been slowly stressed by the photospheric field
evolution,which gradually created a large-scale coronal current sheet, i.e., a
narrow layer with intense current, in the core of the AR. The current layer was
successively enhanced until it became so thin that a tether-cutting
reconnection between the sheared magnetic arcades was set in, which led to a
flare. The modeled reconnecting field lines and their footpoints match well the
observed hot flaring loops and the flare ribbons, respectively, suggesting that
the model has successfully "reproduced" the macroscopic magnetic process of the
flare. In particular, with simulation, we explained why this event is a
confined eruption-the consequent of the reconnection is the shared arcade
instead of a newly formed flux rope. We also found much weaker magnetic
implosion effect comparing to many other X-class flares


title: The Dawn of Multi-Messenger Astronomy

abstract:
  The recent discoveries of high-energy astrophysical neutrinos and
gravitational waves have opened new windows of exploration to the Universe.
Combining neutrino observations with measurements of electromagnetic radiation
and cosmic rays promises to unveil the sources responsible for the neutrino
emission and to help solve long-standing problems in astrophysics such as the
origin of cosmic rays. Neutrino observations may also help localize
gravitational-wave sources, and enable the study of their astrophysical
progenitors. In this work we review the current status and future plans for
multi-messenger searches of neutrino sources.


title: Landau levels of cold dense quark matter in a strong magnetic field

abstract:
  The occupied Landau levels of strange quark matter are investigated in the
framework of the SU(3) NJL model with a conventional coupling and a
magnetic-field dependent coupling respectively. At lower density, the Landau
levels are mainly dominated by u and d quarks. Threshold values of the chemical
potential for the s quark onset are shown in the $\mu$-$B$ plane. The
magnetic-field-dependent running coupling can broaden the region of
three-flavor matter by decreasing the dynamical masses of $s$ quarks. Before
the onset of $s$ quarks, the Landau level number of light quarks is directly
dependent on the magnetic field strength $B$ by a simple inverse proportional
relation $k_{i,\mathrm{max}}\approx B_i^0/B$ with $B_d^0=5\times 10^{19}$ G,
which is approximately 2 times $B_u^0$ of $u$ quarks at a common chemical
potential. When the magnetic field increases up to $B^0_d$, almost all three
flavors are lying in the lowest Landau level.


title: Comptage des multiplicit\'es dans une hypersurface sur un corps fini

abstract:
  In this paper, we consider a problem of counting multiplicities. We fix a
counting function of multiplicity of rational points in a hypersurface of a
projective space over a finite field, and we give an upper bound for the sum
with respect to this counting function in terms of the degree of the
hypersurface, the dimension and the cardinality of the finite field. This upper
bound gives a description of the complexity of the singular locus of this
hypersurface. In order to obtain this upper bound, we introduce a notion called
intersection tree by intersection theory. We construct a sequence of
intersections, such that the multiplicity of a singular rational point is equal
to that of one of the irreducible components in these intersections. The
multiplicities of these irreducible components constructed above are bounded by
their multiplicities in the intersection tree.


title:
Boundary conditions for phosphorene nanoribbons in the continuum
  approach

abstract:
  We investigate the energy spectrum of single layer black phosphorene
nanoribbons (BPN) by means of a low-energy expansion of a recently proposed
tight-binding model that describes electron and hole bands close to the Fermi
energy level. Using the continuum approach, we propose boundary conditions
based on sublattice symmetries for BPN with zigzag and armchair edges and show
that our results for the energy spectra exhibit good agreement with those
obtained by using the five-parameter tight-binding model. We also explore the
behaviour of the energy gap versus the nanoribbon width $W$. Our findings
demonstrate that band gap of armchair BPNs scale as $1/W^2$, while zigzag BPNs
exhibit a $1/W$ tendency. We analyse the different possible combinations of the
zigzag edges that result two-fold degenerate and non-degenerate edge states.
Furthermore, we obtain expressions for the wave functions and discuss the limit
of validity of such analytical model.


title: A Monte Carlo Algorithm for Immiscible Two-Phase Flow in Porous Media

abstract:
  We present a Markov Chain Monte Carlo algorithm based on the Metropolis
algorithm for simulation of the flow of two immiscible fluids in a porous
medium under macroscopic steady-state conditions using a dynamical pore network
model that tracks the motion of the fluid interfaces. The Monte Carlo algorithm
is based on the configuration probability, where a configuration is defined by
the positions of all fluid interfaces. We show that the configuration
probability is proportional to the inverse of the flow rate. Using a
two-dimensional network, advancing the interfaces using time integration the
computational time scales as the linear system size to the fourth power,
whereas the Monte Carlo computational time scales as the linear size to the
second power. We discuss the strengths and the weaknesses of the algorithm.


title:
Tunneling into a quantum confinement created by a single-step
  nano-lithography of conducting oxide interfaces

abstract:
  A new nano-lithography technique compatible with conducting oxide interfaces,
which requires a single lithographic step with no additional amorphous layer
deposition or etching, is presented. It is demonstrated on SrTiO3/LaAlO3
interface where a constriction is patterned in the electron liquid. We find
that an additional back-gating can further confine the electron liquid into an
isolated island. Conductance and differential conductance measurements show
resonant tunneling through the island. The data at various temperatures and
magnetic fields are analyzed and the effective island size is found to be of
the order of 10nm. The magnetic field dependence suggests absence of spin
degeneracy in the island. Our method is suitable for creating superconducting
and oxide-interface based electronic devices.


title:
Multiscale method, Central extensions and a generalized Craik-Leibovich
  equation

abstract:
  In this paper we develop perturbation theory on the reduced space of a
principal $G-$bundle. This theory uses a multiscale method and is related to
vibrodynamics. For a fast oscillating motion with the symmetry Lie group $G$,
we prove that the averaged equation (i.e. the equation describing the slow
motion) is the Euler equation on the dual of a certain central extension of the
corresponding Lie algebra $\mathfrak g$. As an application of this theory we
study the Craik--Leibovich (CL) equation in hydrodynamics. We show that CL
equation can be regarded as the Euler equation on the dual of an appropriate
central extension of the Lie algebra of divergence-free vector fields. From
this geometric point of view, one can give a generalization of CL equation on
any Riemannian manifold with boundary. For accuracy of the averaged equation,
we prove that the difference between the solution of the averaged equation and
the solution of the perturbed equation remains small (of order $\epsilon$) over
a very long time interval (of order $1/{\epsilon^2}$). Combining the geometric
structure of the generalized CL equation and the averaging theorem, we present
a large class of adiabatic invariants for the perturbation model of the
Langmuir circulation in the ocean.


title: Core-EP Decomposition and its Applications

abstract:
  In this paper, we introduce the notion of the core-EP decomposition and some
of its properties. By using the decomposition, we derive several
characterizations of the core-EP inverse, introduce a pre-order(i.e. the
core-EP order) and a partial order(i.e. the core-minus partial order), and
characterize the properties of both orders.


title: A Variant of the Erd\H{o}s-S\'os Conjecture

abstract:
  A well-known conjecture of Erd\H{o}s and S\'os states that every graph with
average degree exceeding $m-1$ contains every tree with $m$ edges as a
subgraph. We propose a variant of this conjecture, which states that every
graph of maximum degree exceeding $m$ and minimum degree at least $\lfloor
\frac{2m}{3}\rfloor$ contains every tree with $m$ edges.
  As evidence for our conjecture we show (i) for every $m$ there is a $g(m)$
such that the weakening of the conjecture obtained by replacing $m$ by $g(m)$
holds, and (ii) there is a $\gamma>0$ such that the weakening of the conjecture
obtained by replacing $\lfloor \frac{2m}{3}\rfloor$ by $(1-\gamma)m$ holds.


title:
Fully integrated 3.2 Gbps quantum random number generator with real-time
  extraction

abstract:
  We present a real-time and fully integrated quantum random number generator
(QRNG) by measuring laser phase fluctuations. The QRNG scheme based on laser
phase fluctuations is featured for its capability of generating ultra
high-speed random numbers. However, the speed bottleneck of a practical QRNG
lies on the limited speed of randomness extraction. To close the gap between
the fast randomness generation and the slow post-processing, we propose a
pipeline extraction algorithm based on Toeplitz matrix hashing and implement it
in a high-speed field-programmable gate array. Further, all the QRNG components
are integrated into a module, including a compact and actively stabilized
interferometer, high-speed data acquisition, and real-time data post-processing
and transmission. The final generation rate of the QRNG module with real-time
extraction can reach 3.2 Gbps.


title:
Electrical properties of III-Nitride LEDs: recombination-based injection
  model and theoretical limits to electrical efficiency and electroluminescent
  cooling

abstract:
  The current-voltage characteristic and ideality factor of III-Nitride quantum
well light-emitting diodes (LEDs) grown on bulk GaN substrates are
investigated. At operating temperature, these electrical properties exhibit a
simple behavior. A model in which only active-region recombinations have a
contribution to the LED current is found to account for experimental results.
The limit of LED electrical efficiency is discussed based on the model and on
thermodynamic arguments, and implications for electroluminescent cooling are
examined.


title:
Sharp endpoint estimates for eigenfunctions restricted to submanifolds
  of codimension 2

abstract:
  Burq-G\'erard-Tzvetkov and Hu established $L^p$ estimates ($2\le p\le
\infty$) for the restriction of eigenfunctions to submanifolds. The estimates
are sharp, except for the log loss at the endpoint $L^2$ estimates for
submanifolds of codimension 2. It has long been believed that the log loss at
the endpoint can be removed in general, while the problem is still open. So
this paper is devoted to the study of sharp endpoint restriction estimates for
eigenfunctions in this case. Chen and Sogge removed the log loss for the
geodesics on 3-dimensional manifolds. In this paper, we generalize their result
to higher dimensions and prove that the log loss can be removed for totally
geodesic submanifolds of codimension 2. Moreover, on 3-dimensional manifolds,
we can remove the log loss for curves with nonvanishing geodesic curvatures,
and more general finite type curves. The problem in 3D is essentially related
to Hilbert transforms along curves in the plane and a class of singular
oscillatory integrals studied by Phong-Stein, Ricci-Stein, Pan, Seeger,
Carbery-P\'erez.


title:
Stacking-sequence-independent band structure and shear exfoliation of
  two-dimensional electride materials

abstract:
  The electronic band structure of crystals is generally influenced by the
periodic arrangement of their constituent atoms. Specifically, the emerging
two-dimensional (2D) layered structures have shown different band structures
with respect to their stacking configurations. Here, based on first-principles
density-functional theory calculations, we demonstrate that the band structure
of the recently synthesized 2D Ca$_2$N electride changes little for the
stacking sequence as well as the lateral interlayer shift. This intriguing
invariance of band structure with respect to geometrical variations can be
attributed to a complete screening of [Ca$_2$N]$^{+}$ cationic layers by
anionic excess electrons delocalized between the cationic layers. The resulting
weak interactions between 2D dressed cationic layers give rise to not only a
shallow potential barrier for bilayer sliding but also an electron-doping
facilitated shear exfoliation. Our findings open a route for exploration of the
peculiar geometry-insensitive electronic properties in 2D electride materials,
which will be useful for future thermally stable electronic applications.


title:
Phylogenomic Analyses of Large-scale Nuclear Genes Provide New Insights
  into the Evolutionary Relationships within the Rosids

abstract:
  The Rosids is one of the largest groups of flowering plants, with 140
families and ~70,000 species. Previous phylogenetic studies of the rosids have
primarily utilized organelle genes that likely differ in evolutionary histories
from nuclear genes. To better understand the evolutionary history of rosids, it
is necessary to investigate their phylogenetic relationships using nuclear
genes. Here, we employed large-scale phylogenomic datasets composed of nuclear
genes, including 891 clusters of putative orthologous genes. Combined with
comprehensive taxon sampling covering 63 species representing 14 out of the 17
orders, we reconstructed the rosids phylogeny with coalescence and
concatenation methods, yielding similar tree topologies from all datasets.
However, these topologies did not agree on the placement of Zygophyllales.
Through comprehensive analyses, we found that missing data and gene tree
heterogeneity were potential factors that may mislead concatenation methods, in
particular, large amounts of missing data under high gene tree heterogeneity.
Our results provided new insights into the deep phylogenetic relationships of
the rosids, and demonstrated that coalescence methods may effectively resolve
the phylogenetic relationships of the rosids with missing data under high gene
tree heterogeneity.


title: Zero-Shot Learning with Multi-Battery Factor Analysis

abstract:
  Zero-shot learning (ZSL) extends the conventional image classification
technique to a more challenging situation where the test image categories are
not seen in the training samples. Most studies on ZSL utilize side information
such as attributes or word vectors to bridge the relations between the seen
classes and the unseen classes. However, existing approaches on ZSL typically
exploit a shared space for each type of side information independently, which
cannot make full use of the complementary knowledge of different types of side
information. To this end, this paper presents an MBFA-ZSL approach to embed
different types of side information as well as the visual feature into one
shared space. Specifically, we first develop an algorithm named Multi-Battery
Factor Analysis (MBFA) to build a unified semantic space, and then employ
multiple types of side information in it to achieve the ZSL. The close-form
solution makes MBFA-ZSL simple to implement and efficient to run on large
datasets. Extensive experiments on the popular AwA, CUB, and SUN datasets show
its significant superiority over the state-of-the-art approaches.


title:
Higher order minimal families of rational curves and Fano manifolds with
  nef Chern characters

abstract:
  In this paper, we investigate higher order minimal families $H_i$ of rational
curves associated to Fano manifolds $X$. We prove that $H_i$ is also a Fano
manifold if the Chern characters of $X$ satisfy some positivity conditions. We
also provide a sufficient condition for Fano manifolds to be covered by higher
rational manifolds.


title: Broadband Multifocal Conic-Shaped Metalens

abstract:
  Multifocal lens, which focus incident light at multiple foci, are widely used
in imaging systems and optical communications. However, for the traditional
design strategy, it combines several lenses that have different focal points
into a planar integrated unit, resulting a low imaging quality due to the high
background noise. Here, we propose two kinds of multifocal metalens with Au
nanoslits arranged in an elliptical and a hyperbolic shape, which are able to
effectively focus incident light at all of the foci with constructive
interference, and extremely decrease the background noise and improve the lens
imaging performance at the nanoscale. We further demonstrate that, the proposed
metalens can possess a broadband operation wavelength changed from 600 nm to
900 nm, with its dual-polarity actively controlled by the incident circular
polarization lights. With great agreement between the experimental and
simulation results, our proposed conic-shaped metalens provides a significant
potential for the future integrated nanophotonic device.


title:
OGLE-2015-BLG-0051/KMT-2015-BLG-0048Lb: a Giant Planet Orbiting a
  Low-mass Bulge Star Discovered by High-cadence Microlensing Surveys

abstract:
  We report the discovery of an extrasolar planet detected from the combined
data of a microlensing event OGLE-2015-BLG-0051/KMT-2015-BLG-0048 acquired by
two microlensing surveys. Despite that the short planetary signal occurred in
the very early Bulge season during which the lensing event could be seen for
just about an hour, the signal was continuously and densely covered. From the
Bayesian analysis using models of the mass function, matter and velocity
distributions combined with the information of the angular Einstein radius, it
is found that the host of the planet is located in the Galactic bulge. The
planet has a mass $0.72_{-0.07}^{+0.65}\ M_{\rm J}$ and it is orbiting a
low-mass M-dwarf host with a projected separation $d_\perp=0.73 \pm 0.08$ AU.
The discovery of the planet demonstrates the capability of the current
high-cadence microlensing lensing surveys in detecting and characterizing
planets.


title: Yang-Mills-Higgs connections on Calabi-Yau manifolds, II

abstract:
  In this paper we study Higgs and co-Higgs $G$-bundles on compact K\"ahler
manifolds $X$. Our main results are: (1) If $X$ is Calabi-Yau, and
$(E,\,\theta)$ is a semistable Higgs or co-Higgs $G$-bundle on $X$, then the
principal $G$-bundle $E$ is semistable. In particular, there is a deformation
retract of ${\mathcal M}_H(G)$ onto $\mathcal M(G)$, where $\mathcal M(G)$ is
the moduli space of semistable principal $G$-bundles with vanishing rational
Chern classes on $X$, and analogously, ${\mathcal M}_H(G)$ is the moduli space
of semistable principal Higgs $G$-bundles with vanishing rational Chern
classes. (2) Calabi-Yau manifolds are characterized as those compact K\"ahler
manifolds whose tangent bundle is semistable for every K\"ahler class, and have
the following property: if $(E,\,\theta)$ is a semistable Higgs or co-Higgs
vector bundle, then $E$ is semistable.


title:
Above-the-loop-top Oscillation and Quasi-periodic Coronal Wave
  Generation in Solar Flares

abstract:
  Observations revealed that various kinds of oscillations are excited in solar
flare regions. Quasi-periodic pulsations (QPPs) in the flare emissions are
commonly observed in a wide range of wavelengths. Recent observations have
found that fast-mode magnetohydrodynamic (MHD) waves are quasi-periodically
emitted from some flaring sites (quasi-periodic propagating fast-mode
magnetoacoustic waves; QPFs). Both of QPPs and QPFs imply a cyclic disturbance
originating from the flaring sites. However, the physical mechanisms remain
puzzling. By performing a set of two-dimensional MHD simulations of a solar
flare, we discovered the local oscillation above the loops filled with
evaporated plasma (above-the-loop-top region) and the generation of QPFs from
such oscillating regions. Unlike all previous models for QPFs, our model
includes essential physics for solar flares, such as magnetic reconnection,
heat conduction, and chromospheric evaporation. We revealed that QPFs can be
spontaneously excited by the above-the-loop-top oscillation. It was found that
this oscillation is controlled by the backflow of the reconnection outflow. The
new model revealed that flare loops and the above-the-loop-top region are full
of shocks and waves, which is different from the previous expectations based on
a standard flare model and previous simulations. In this paper, we will show
the QPF generation process based on our new picture of flare loops and will
briefly discuss a possible relationship between QPFs and QPPs. Our findings
will change the current view of solar flares to a new view in which they are a
very dynamic phenomenon with full of shocks and waves.


title:
Disentangling the role of laser coupling in directional breaking of
  molecules

abstract:
  The directional control of molecular dissociation with the laser electric
field waveform is a paradigm and was demonstrated for a variety of molecules.
In most cases, the directional control occurs via a dissociative ionization
pathway. The role of laser-induced coupling of electronic states in the
dissociating ion versus selective ionization of oriented neutral molecules,
however, could not be distinguished for even small heteronuclear molecules such
as CO. Here, we introduce a technique, using elliptically polarized pump and
linearly polarized two-color probe pulses that unambiguously distinguishes the
roles of laser-induced state coupling and selective ionization. The measured
photoelectron momentum distributions governed by the light polarizations allow
us to coincidently identify the ionization and dissociation from the pump and
probe pulses. Directional dissociation of CO+ as a function of the relative
phase of the linearly polarized two-color pulse is observed for both parallel
and orthogonally oriented molecules. We find that the laser-induced coupling of
various electronic states of CO+ plays an important role for the observed
directional bond breaking, which is verified by quantum calculations.


title:
Photovoltage Detection of Edge Magnetoplasmon Oscillations and Giant
  Magnetoplasmon Resonances in A Two-Dimensional Hole System

abstract:
  In our high mobility p-type AlGaAs/GaAs two-dimensional hole samples, we
originally observe the B-periodic oscillation induced by microwave (MW) in
photovoltage (PV) measurements. In the frequency range of our measurements (5 -
40 GHz), the period ({\Delta}B) is inversely proportional to the microwave
frequency (f). The distinct oscillations come from the edge magnetoplasmon
(EMP) in the high quality heavy hole system. In our hole sample with a very
large effective mass, the observation of the EMP oscillations is in neither the
low frequency limit nor the high frequency limit, and the damping of the EMP
oscillations is very weak under high magnetic fields. Simultaneously, we
observe the giant plasmon resonance signals in our measurements on the shallow
two-dimensional hole system (2DHS).


title:
OGLE-2015-BLG-0479LA,B: Binary Gravitational Microlens Characterized by
  Simultaneous Ground-based and Space-based Observation

abstract:
  We present a combined analysis of the observations of the gravitational
microlensing event OGLE-2015-BLG-0479 taken both from the ground and by the
{\it Spitzer Space Telescope}. The light curves seen from the ground and from
space exhibit a time offset of $\sim 13$ days between the caustic spikes,
indicating that the relative lens-source positions seen from the two places are
displaced by parallax effects. From modeling the light curves, we measure the
space-based microlens parallax. Combined with the angular Einstein radius
measured by analyzing the caustic crossings, we determine the mass and distance
of the lens. We find that the lens is a binary composed of two G-type stars
with masses $\sim 1.0\ M_\odot$ and $\sim 0.9\ M_\odot$ located at a distance
$\sim 3$ kpc. In addition, we are able to constrain the complete orbital
parameters of the lens thanks to the precise measurement of the microlens
parallax derived from the joint analysis. In contrast to the binary event
OGLE-2014-BLG-1050, which was also observed by {\it Spitzer}, we find that the
interpretation of OGLE-2015-BLG-0479 does not suffer from the degeneracy
between $(\pm,\pm)$ and $(\pm,\mp)$ solutions, confirming that the four-fold
parallax degeneracy in single-lens events collapses into the two-fold
degeneracy for the general case of binary-lens events. The location of the
blend in the color-magnitude diagram is consistent with the lens properties,
suggesting that the blend is the lens itself. The blend is bright enough for
spectroscopy and thus this possibility can be checked from future follow-up
observations.


title:
Universal Substrate Effect on the Superconductivity of FeSe Monolayer
  Films

abstract:
  To elucidate the mechanisms behind the enhanced $T_c$ in monolayer (1ML) FeSe
on SrTiO$_3$ (STO), we grew highly strained 1ML FeSe on the rectangular (100)
face of rutile TiO$_2$, and observed the coexistence of replica bands and
superconductivity with a $T_c$ of 63 K. From the similar $T_c$ between this
system and 1ML FeSe on STO (001), we conclude that strain and dielectric
constant are likely unimportant to the enhanced $T_c$ in these systems. A
systematic comparison of 1ML FeSe on TiO$_2$ with other systems in the FeSe
family shows that while charge transfer alone can enhance $T_c$, it is only
with the addition of interfacial electron-phonon coupling that $T_c$ can be
increased to the level seen in 1ML FeSe on STO.


title:
On functions of negative type on the Olshanski spherical pair
  $(SL(\infty),SU(\infty))$

abstract:
  In this paper, using a generalized Bochner type representation for Olshanski
spherical pairs, we prove the boundedness of every $SU(\infty)$-biinvariant
continuous function of negative type on the infinite dimensional special linear
group $SL(\infty)$.


title: Quantum simulation of Abelian Wu-Yang monopoles in spin-1/2 systems

abstract:
  With the help of the Berry curvature and the first Chern number
$($$\textit{C}_1$$)$, we both analytically and numerically investigate and thus
simulate artificial magnetic monopoles formed in parameter space of the
Hamiltonian of a driven superconducting qubit. The topological structure of a
spin-1/2 system $($qubit$)$ can be captured by the distribution of Berry
curvature, which describes the geometry of eigenstates of the Hamiltonian.
Degeneracy points in parameter space act as sources $($$\textit{C}_1$ = $1$$)$
or sinks $($$\textit{C}_1$ = $-1$$)$ of the magnetic field. We note that the
strength of the magnetic field $($described by Berry curvature$)$ has an
apparent impact on the quantum states during the process of topological
transition. It exhibits an unusual property that the transition of the quantum
states is asymmetric when the degenerate point passes from outside to inside
and again outside the manifold spanned by system parameters. Our results also
pave the way to explore intriguing properties of magnetic monopoles in other
spin-1/2 systems.


title: Quadrupolar metrics

abstract:
  We review the problem of describing the gravitational field of compact stars
in general relativity. We focus on the deviations from spherical symmetry which
are expected to be due to rotation and to the natural deformations of mass
distributions. We assume that the relativistic quadrupole moment takes into
account these deviations, and consider the class of axisymmetric static and
stationary quadrupolar metrics which satisfy Einstein's equations in empty
space and in the presence of matter represented by a perfect fluid. We
formulate the physical conditions that must be satisfied for a particular
spacetime metric to describe the gravitational field of compact stars. We
present a brief review of the main static and axisymmetric exact solutions of
Einstein's vacuum equations, satisfying all the physical conditions. We discuss
how to derive particular stationary and axisymmetric solutions with quadrupolar
properties by using the solution generating techniques which correspond either
to Lie symmetries and B\"ackund transformations of the Ernst equations or to
the inverse scattering method applied to Einstein's equations. As for interior
solutions, we argue that it is necessary to apply alternative methods to obtain
physically meaningful solutions, and review a method which allows us to
generate interior perfect-fluid solutions.


title: Emergence of L\'{e}vy Walks in Systems of Interacting Individuals

abstract:
  Recent experiments (G. Ariel, et al., Nature Comm. 6, 8396 (2015)) revealed
an intriguing behavior of swarming bacteria: they fundamentally change their
collective motion from simple diffusion into a superdiffusive L\'{e}vy walk
dynamics. We introduce a nonlinear non-Markovian persistent random walk model
that explains the emergence of superdiffusive L\'{e}vy walks. We show that the
alignment interaction between individuals can lead to the superdiffusive growth
of the mean squared displacement and the power law distribution of run length
with infinite variance. The main result is that the superdiffusive behavior
emerges as a nonlinear collective phenomenon, rather than due to the standard
assumption of the power law distribution of run distances from the inception.
At the same time, we find that the repulsion/collision effects lead to the
density dependent exponential tempering of power law distributions. This
qualitatively explains experimentally observed transition from superdiffusion
to the diffusion of mussels as their density increases (M. de Jager et al.,
Proc. R. Soc. B 281, 20132605 (2014)).

categories: cond-mat.stat-mech cond-mat.soft nlin.AO q-bio.CB


title:
A Spectroscopically Confirmed Double Source Plane Lens System in the
  Hyper Suprime-Cam Subaru Strategic Program

abstract:
  We report the serendipitous discovery of HSC J142449-005322, a double source
plane lens system in the Hyper Suprime-Cam Subaru Strategic Program. We dub the
system Eye of Horus. The lens galaxy is a very massive early-type galaxy with
stellar mass of ~7x10^11 Msun located at z_L=0.795. The system exhibits two
arcs/rings with clearly different colors, including several knots. We have
performed spectroscopic follow-up observations of the system with FIRE on
Magellan. The outer ring is confirmed at z_S2=1.988 with multiple emission
lines, while the inner arc and counterimage is confirmed at z_S1=1.302. This
makes it the first double source plane system with spectroscopic redshifts of
both sources. Interestingly, redshifts of two of the knots embedded in the
outer ring are found to be offset by delta_z=0.002 from the other knots,
suggesting that the outer ring consists of at least two distinct components in
the source plane. We perform lens modeling with two independent codes and
successfully reproduce the main features of the system. However, two of the
lensed sources separated by ~0.7 arcsec cannot be reproduced by a smooth
potential, and the addition of substructure to the lens potential is required
to reproduce them. Higher-resolution imaging of the system will help decipher
the origin of this lensing feature and potentially detect the substructure.


title:
Non-linear excitation of quantum emitters in two-dimensional hexagonal
  boron nitride

abstract:
  Two-photon absorption is an important non-linear process employed for high
resolution bio-imaging and non-linear optics. In this work we realize
two-photon excitation of a quantum emitter embedded in a two-dimensional
material. We examine defects in hexagonal boron nitride and show that the
emitters exhibit similar spectral and quantum properties under one-photon and
two-photon excitation. Furthermore, our findings are important to deploy
two-dimensional hexagonal boron nitride for quantum non-linear photonic
applications.


title:
On the worst-case complexity of the gradient method with exact line
  search for smooth strongly convex functions

abstract:
  We consider the gradient (or steepest) descent method with exact line search
applied to a strongly convex function with Lipschitz continuous gradient. We
establish the exact worst-case rate of convergence of this scheme, and show
that this worst-case behavior is exhibited by a certain convex quadratic
function. We also give the tight worst-case complexity bound for a noisy
variant of gradient descent method, where exact line-search is performed in a
search direction that differs from negative gradient by at most a prescribed
relative tolerance.
  The proofs are computer-assisted, and rely on the resolutions of semidefinite
programming performance estimation problems as introduced in the paper [Y.
Drori and M. Teboulle. Performance of first-order methods for smooth convex
minimization: a novel approach. Mathematical Programming, 145(1-2):451-482,
2014].


title:
Dissipation, dephasing and quantum Darwinism in qubit systems with
  random unitary interactions

abstract:
  We investigate the influence of dissipation and decoherence on quantum
Darwinism by generalizing Zurek's original qubit model of decoherence and the
establishment of pointer states (Zurek, Nature Physics 5, 181 - 188 (2009)).
Our model allows for repeated multiple qubit-qubit couplings between system and
environment which are described by randomly applied two-qubit quantum
operations inducing entanglement, dissipation and dephasing. The resulting
stationary qubit states of system and environment are investigated. They
exhibit the intricate influence of entanglement generation, dissipation and
dephasing on this characteristic quantum phenomenon.


title:
Parking Stall Vacancy Indicator System Based on Deep Convolutional
  Neural Networks

abstract:
  Parking management systems, and vacancy-indication services in particular,
can play a valuable role in reducing traffic and energy waste in large cities.
Visual detection methods represent a cost-effective option, since they can take
advantage of hardware usually already available in many parking lots, namely
cameras. However, visual detection methods can be fragile and not easily
generalizable. In this paper, we present a robust detection algorithm based on
deep convolutional neural networks. We implemented and tested our algorithm on
a large baseline dataset, and also on a set of image feeds from actual cameras
already installed in parking lots. We have developed a fully functional system,
from server-side image analysis to front-end user interface, to demonstrate the
practicality of our method.


title:
Probabilistic Construction and Analysis of Seminormalized Hadamard
  Matrices

abstract:
  Let o be a 4k-length column vector whose all entries are 1s, with k a
positive integer. Let V={v_i} be a set of semi-normalized Hadamard
(SH)-vectors, which are 4k-length vectors whose 2k entries are -1s and the
remaining 2k are 1s. We define a 4k-order QSH (Quasi SH)-matrix, Q, as a 4kx4k
matrix where the first column is o and the remaining ones are distinct v_i in
V. When Q is orthogonal, it becomes an SH-matrix H. Therefore, 4k-order
SH-matrices can be built by enumerate all possible Q from every combination of
v_i, then evaluate the orthogonality of each one of them. Since such exhaustive
method requires a large amount of computing resource, we can employ
probabilistic algorithms to construct H, such as, by Random Vector Selection
(RVS) or the Orthogonalization by Simulated Annealing (OSA) algorithms. We
demonstrate the constructions of low-order SH-matrices by using these methods.
We also analyze some probabilistic aspects of the constructions, including
orthogonal probability p between a pair of randomly selected SH-vectors, the
existence probability p_H|Q that a randomly generated Q is in fact an SH-matrix
H, and address the discrepancy of the distribution between the known number of
SH-matrix with expected number derived from the probabilistic analysis.


title: Superconductivity at 5.5 K in Nb2PdSe5 compound

abstract:
  We report superconductivity in as synthesized Nb2PdSe5, which is similar to
recently discovered Nb2PdS5 compound having very high upper critical field,
clearly above the Pauli paramagnetic limit [Sci. Rep. 3, 1446 (2013)]. A bulk
polycrystalline Nb2PdSe5 sample is synthesized by solid state reaction route in
phase pure structure. The structural characterization has been done by X ray
diffraction, followed by Rietveld refinements, which revealed that Nb2PdSe5
sample is crystallized in monoclinic structure with in space group C2/m.
Structural analysis revealed the formation of sharing of one dimensional PdSe2
chains. Electrical and magnetic measurements confirmed superconductivity in
Nb2PdSe5 compound at 5.5K. Detailed magneto-resistance results, exhibited the
value of upper critical field to be around 8.2Tesla. The estimated Hc2(0) is
within Pauli Paramagnetic limit, which is unlike the Nb2PdS5.


title:
Relation extraction from clinical texts using domain invariant
  convolutional neural network

abstract:
  In recent years extracting relevant information from biomedical and clinical
texts such as research articles, discharge summaries, or electronic health
records have been a subject of many research efforts and shared challenges.
Relation extraction is the process of detecting and classifying the semantic
relation among entities in a given piece of texts. Existing models for this
task in biomedical domain use either manually engineered features or kernel
methods to create feature vector. These features are then fed to classifier for
the prediction of the correct class. It turns out that the results of these
methods are highly dependent on quality of user designed features and also
suffer from curse of dimensionality. In this work we focus on extracting
relations from clinical discharge summaries. Our main objective is to exploit
the power of convolution neural network (CNN) to learn features automatically
and thus reduce the dependency on manual feature engineering. We evaluate
performance of the proposed model on i2b2-2010 clinical relation extraction
challenge dataset. Our results indicate that convolution neural network can be
a good model for relation exaction in clinical text without being dependent on
expert's knowledge on defining quality features.


title:
Recurrent neural network models for disease name recognition using
  domain invariant features

abstract:
  Hand-crafted features based on linguistic and domain-knowledge play crucial
role in determining the performance of disease name recognition systems. Such
methods are further limited by the scope of these features or in other words,
their ability to cover the contexts or word dependencies within a sentence. In
this work, we focus on reducing such dependencies and propose a
domain-invariant framework for the disease name recognition task. In
particular, we propose various end-to-end recurrent neural network (RNN) models
for the tasks of disease name recognition and their classification into four
pre-defined categories. We also utilize convolution neural network (CNN) in
cascade of RNN to get character-based embedded features and employ it with
word-embedded features in our model. We compare our models with the
state-of-the-art results for the two tasks on NCBI disease dataset. Our results
for the disease mention recognition task indicate that state-of-the-art
performance can be obtained without relying on feature engineering. Further the
proposed models obtained improved performance on the classification task of
disease names.


title:
Competition between finite-size effects and dipole-dipole interactions
  in few-atom systems

abstract:
  In this paper, we study the competition between finite-size effects (i.e.
discernibility of particles) and dipole-dipole interactions in few-atom systems
coupled to the electromagnetic field in vacuum. We consider two hallmarks of
cooperative effects, superradiance and subradiance, and compute for each the
rate of energy radiated by the atoms and the coherence of the atomic state
during the time evolution. We adopt a statistical approach in order to extract
the typical behavior of the atomic dynamics and average over random atomic
distributions in spherical containers with prescribed $k_0R$ with $k_0$ the
radiation wavenumber and $R$ the average interatomic distance. Our approach
allows us to highlight the tradeoff between finite-size effects and
dipole-dipole interactions in superradiance/subradiance. In particular, we show
the existence of an optimal value of $k_0R$ for which the superradiant
intensity and coherence pulses are the less affected by dephasing effects
induced by dipole-dipole interactions and finite-size effects.


title:
The effect of minijet on hadron spectra and azimuthal anisotropy in
  heavy-ion collisions

abstract:
  Here I review the transverse momentum distributions of identified hadrons
produced in Au-Au collisions at RHIC and Pb-Pb collisions at LHC in the
framework of recombination model. Minijets play an important role in generating
shower partons in the intermediate $p_T$ region. At LHC, the resultant soft
shower partons are even found to dominate over the thermal partons in the
non-strange sector. The azimuthal anisotropy of the produced hadrons could also
be explained as the consequence of the effects of minijets. Harmonic analysis
of the $\phi$ dependence leads to $v_n(p_T, b)$ that can be well produced
without reference to flow.


title: Flows with Ratner's property have discrete essential centralizer

abstract:
  We show that a free, ergodic action of $\mathbb{R}$ with (finite) Ratner's
property has countable discrete essential centralizer. Moreover we show that
such flows are mildly mixing.


title:
Convolutional Neural Networks on Graphs with Fast Localized Spectral
  Filtering

abstract:
  In this work, we are interested in generalizing convolutional neural networks
(CNNs) from low-dimensional regular grids, where image, video and speech are
represented, to high-dimensional irregular domains, such as social networks,
brain connectomes or words' embedding, represented by graphs. We present a
formulation of CNNs in the context of spectral graph theory, which provides the
necessary mathematical background and efficient numerical schemes to design
fast localized convolutional filters on graphs. Importantly, the proposed
technique offers the same linear computational complexity and constant learning
complexity as classical CNNs, while being universal to any graph structure.
Experiments on MNIST and 20NEWS demonstrate the ability of this novel deep
learning system to learn local, stationary, and compositional features on
graphs.


title: The Design of Arbitrage-Free Data Pricing Schemes

abstract:
  Motivated by a growing market that involves buying and selling data over the
web, we study pricing schemes that assign value to queries issued over a
database. Previous work studied pricing mechanisms that compute the price of a
query by extending a data seller's explicit prices on certain queries, or
investigated the properties that a pricing function should exhibit without
detailing a generic construction. In this work, we present a formal framework
for pricing queries over data that allows the construction of general families
of pricing functions, with the main goal of avoiding arbitrage. We consider two
types of pricing schemes: instance-independent schemes, where the price depends
only on the structure of the query, and answer-dependent schemes, where the
price also depends on the query output. Our main result is a complete
characterization of the structure of pricing functions in both settings, by
relating it to properties of a function over a lattice. We use our
characterization, together with information-theoretic methods, to construct a
variety of arbitrage-free pricing functions. Finally, we discuss various
tradeoffs in the design space and present techniques for efficient computation
of the proposed pricing functions.


title: A note on spherical functors

abstract:
  We provide a new and very short proof of the fact that a spherical functor
between certain triangulated categories induces an autoequivalence.


title:
On the matrix realization of the Lie superalgebra of contact projective
  vector fields $\mathfrak{spo}(2l+2|n)$

abstract:
  In this paper, we show that the Lie superalgebra $\mathfrak{spo}(2l+2|n)$ is
into the intersection of Lie superalgebra of contact vector fields
$\mathcal{K}(2l+1|n)$ and the Lie superalgebra of projective vector fields
$\mathfrak{pgl}(2l+2|n)$. We use mainly the embedding used by P. Mathonet and
F. Radoux in "\textit{ Projectively equivariant quantizations over superspace
$\mathbb{R}^{p|q}$. Lett. Math. Phys, 98: 311-331, 2011}". Explicitly, we use
the embedding of a Lie superalgebra constituted of matrices belonging to
$\gl(2l+2|n)$ into $\mathrm{Vect}(\R^{2l+1|n})$. We generalize thus in
superdimension $2l+1-n$, the matrix realization described in \cite{MelNibRad13}
on $S^{1|2}$. We mention that the intersection
$\spo(2l+2|n)=\pgl(2l+2|n)\cap\cK(2l+1|n)$ that we prove here, in super case,
has been prooved on $\R^{2l+2}$ in even case in \cite{CoOv12}.


title:
(Anti-)deuteron production and anisotropic flow measured with ALICE at
  the LHC

abstract:
  The high abundance of (anti-)deuterons in the statistics gathered in Run 1 of
the LHC and the excellent performance of the ALICE setup allow for the
simultaneous measurement of the elliptic flow and the deuteron production rates
with a large transverse momentum ($p_{\rm T}$) reach. The (anti-) deuterons are
identified using the specific energy loss in the time projection chamber and
the velocity information in the time-of-flight detector. The elliptic flow of
(anti-)deuterons can provide insight into the production mechanisms of
particles in heavy-ion collisions. Quark coalescence is one of the approaches
to describe the elliptic flow of hadrons, while the production of light nuclei
can be also depicted as a coalescence of nucleons. In these proceedings, the
measured $v_{2}$ of deuterons produced in Pb--Pb collisions at
$\sqrt{s_{\mathrm{NN}}}$=2.76TeV will be compared to expectations from
coalescence and hydrodynamic models.


title:
$CP$ violation for $B^+_{c}\rightarrow D_{(s)}^+\pi^+\pi^-$ in
  Perturbative QCD

abstract:
  In the perturbative QCD (PQCD) approach we study the direct $CP$ violation in
$B^+_{c}\rightarrow D_{(s)}^+\rho^0(\omega) \rightarrow D_{(s)}^+\pi^+\pi^-$
via the $\rho-\omega$ mixing mechanism. We find that the $CP$ violation can be
enhanced by $\rho-\omega$ mixing when the invariant masses of the $\pi^+\pi^-$
pairs are in the vicinity of the $\omega$ resonance. For the decay process
$B^+_{c}\rightarrow D^+\rho^0(\omega) \rightarrow D^+\pi^+\pi^-$, the maximum
$CP$ violation can reach 7.5 {\%}.


title:
Helicity, anisotropies and their competition in a multiferroic magnet:
  insight from the phase diagram

abstract:
  Motivated by the complex phase diagram of MnWO4, we investigate competition
between anisotropy, magnetic field, and helicity for the anisotropic
next-nearest-neighbor Heisenberg model. Apart from two competing exchanges,
which favor a spiral magnetic structure, the model features the bi-axial
single-ion anisotropy. The model is treated in the real-space mean-field
approximation and the phase diagram containing various incommensurate and
commensurate states is obtained for different field orientations. We discuss
similarities and differences of the theoretical phase diagram and the
experimental diagram of MnWO4.


title:
The problem of missing terms in term by term integration involving
  divergent integrals

abstract:
  Term by term integration may lead to divergent integrals, and naive
evaluation of them by means of, say, analytic continuation or by regularization
or by the finite part integral may lead to missing terms. Here, under certain
analyticity condition, the problem of missing terms for the incomplete
Stieltjes transform, $\int_0^a f(x) (\omega+x)^{-1} \mathrm{d}x$, and the
Stieltjes transform itself, $\int_0^{\infty} f(x) (\omega+x)^{-1} \mathrm{d}x$,
is resolved by lifting the integration in the complex plane. It is shown that
the missing terms arise from the singularities of the complex valued function
$f(z) (\omega + z)^{-1}$, with the divergent integrals arising from term by
term integration interpreted as finite part integrals.


title:
On Approximate Dynamic Programming with Multivariate Splines for
  Adaptive Control

abstract:
  We define a SDP framework based on the RLSTD algorithm and multivariate
simplex B-splines. We introduce a local forget factor capable of preserving the
continuity of the simplex splines. This local forget factor is integrated with
the RLSTD algorithm, resulting in a modified RLSTD algorithm that is capable of
tracking time-varying systems. We present the results of two numerical
experiments, one validating SDP and comparing it with NDP and another to show
the advantages of the modified RLSTD algorithm over the original. While SDP
requires more computations per time-step, the experiment shows that for the
same amount of function approximator parameters, there is an increase in
performance in terms of stability and learning rate compared to NDP. The second
experiment shows that SDP in combination with the modified RLSTD algorithm
allows for faster recovery compared to the original RLSTD algorithm when system
parameters are altered, paving the way for an adaptive high-performance
non-linear control method.


title: On the cohomology of Gushel-Mukai sixfolds

abstract:
  We provide a stable rationality construction for some smooth complex
Gushel-Mukai varieties of dimension 6. As a consequence, we compute the
integral singular cohomology of any smooth Gushel-Mukai sixfold and in
particular, show that it is torsion-free.


title:
Nucleon-pion-state contribution in lattice calculations of the nucleon
  charges $g_A,g_T$ and $g_S$

abstract:
  We employ leading order covariant chiral perturbation theory to compute the
nucleon-pion-state contribution to the 3-point correlation functions one
typically measures in lattice QCD to extract the isovector nucleon charges
$g_A,g_T$ and $g_S$. We estimate the impact of the nucleon-pion-state
contribution on both the plateau and the summation method for lattice
simulations with physical pion masses. The nucleon-pion-state contribution
results in an overestimation of all charges with both methods. The
overestimation is roughly equal for the axial and the tensor charge, and about
fifty percent larger for the scalar charge.


title:
Continuous rotation of achiral nematic liquid crystal droplets driven by
  heat flux

abstract:
  Suspended droplets of cholesteric (chiral nematic) liquid crystals
spontaneously rotate in the presence of a heat flux due to a temperature
gradient, a phenomenon known as Lehmann effect. So far, it is not clear whether
this effect is due to the chirality of the phase and the molecules or only to
the chirality of the director field. Here, we report the continuous rotation in
a temperature gradient of nematic droplets of a lyotropic chromonic liquid
crystal featuring a twisted bipolar configuration. The achiral nature of the
molecular components leads to a random handedness of the spontaneous twist,
resulting in the coexistence of droplets rotating in the two senses, with
speeds proportional to the temperature gradient and inversely proportional to
the droplet radius. This result shows that a macroscopic twist of the director
field is sufficient to induce a rotation of the droplets, and that the phase
and the molecules do not need to be chiral. This suggests that one can also
explain the Lehmann rotation in cholesteric liquid crystals without introducing
the Leslie thermomechanical coupling -- only present in chiral mesophases. An
explanation based on the Akopyan and Zeldovich theory of thermomechanical
effects in nematics is proposed and discussed.