title: Markov Type constants, flat tori and Wasserstein spaces

abstract:
  Let $M_p(X,T)$ denote the Markov type $p$ constant at time $T$ of a metric
space $X$, where $p \ge 1$. We show that $M_p(Y,T) \le M_p(X,T)$ in each of the
following cases: (a)$X$ and $Y$ are geodesic spaces and $Y$ is covered by $X$
via a finite-sheeted locally isometric covering, (b)$Y$ is the quotient of $X$
by a finite group of isometries, (c) $Y$ is the $L^p$-Wasserstein space over
$X$.
  As an application of (a) we show that all compact flat manifolds have Markov
type $2$ with constant $1$. In particular the circle with its intrinsic metric
has Markov type $2$ with constant $1$. This answers the question raised by
S.-I. Ohta and M. Pichot.
  Parts (b) and (c) imply new upper bounds for Markov type constants of the
$L^p$-Wasserstein space over $\mathbb R^d$. These bounds were conjectured by A.
Andoni, A. Naor and O. Neiman. They imply certain restrictions on bi-Lipschitz
embeddability of snowflakes into such Wasserstein spaces.


title:
Free standing membranes to study the optical properties of anodic TiO2
  nanotube layers

abstract:
  In the present work we investigate various optical properties (such as light
absorption and reflectance) of anodic TiO2 nanotubes layers directly
transferred as self-standing membranes onto quartz substrates. This allows
investigation in a transmission geometry which provides significantly more
reliable data than measurements on the metallic Ti substrate. Light
transmission and reflectance measurements were carried out for layers of
thicknesses varying from 1.8 to 50 micrometer, and the layers were investigated
in their amorphous and crystalline form. A series of wavelength-dependent light
attenuation coefficients are extrapolated and found to match the photocurrent
vs. irradiation wavelength behavior. However, a feature specific to anodic
nanotubes is that their intrinsic carbon content causes a sub-bandgap response
that is proportional to the carbon contamination content in the TiO2 nanotubes.
Overall the extracted data provide valuable basis and understanding for the
design of photo-electrochemical devices based on TiO2 nanotubes.


title: Quantitative null-cobordism

abstract:
  For a given null-cobordant Riemannian $n$-manifold, how does the minimal
geometric complexity of a null-cobordism depend on the geometric complexity of
the manifold? In [Gro99], Gromov conjectured that this dependence should be
linear. We show that it is at most a polynomial whose degree depends on $n$.
  This construction relies on another of independent interest. Take $X$ and $Y$
to be sufficiently nice compact metric spaces, such as Riemannian manifolds or
simplicial complexes. Suppose $Y$ is simply connected and rationally homotopy
equivalent to a product of Eilenberg-MacLane spaces: for example, any simply
connected Lie group. Then two homotopic L-Lipschitz maps $f, g : X \rightarrow
Y$ are homotopic via a $CL$-Lipschitz homotopy. We present a counterexample to
show that this is not true for larger classes of spaces $Y$.


title:
Real-time Joint Tracking of a Hand Manipulating an Object from RGB-D
  Input

abstract:
  Real-time simultaneous tracking of hands manipulating and interacting with
external objects has many potential applications in augmented reality, tangible
computing, and wearable computing. However, due to difficult occlusions, fast
motions, and uniform hand appearance, jointly tracking hand and object pose is
more challenging than tracking either of the two separately. Many previous
approaches resort to complex multi-camera setups to remedy the occlusion
problem and often employ expensive segmentation and optimization steps which
makes real-time tracking impossible. In this paper, we propose a real-time
solution that uses a single commodity RGB-D camera. The core of our approach is
a 3D articulated Gaussian mixture alignment strategy tailored to hand-object
tracking that allows fast pose optimization. The alignment energy uses novel
regularizers to address occlusions and hand-object contacts. For added
robustness, we guide the optimization with discriminative part classification
of the hand and segmentation of the object. We conducted extensive experiments
on several existing datasets and introduce a new annotated hand-object dataset.
Quantitative and qualitative results show the key advantages of our method:
speed, accuracy, and robustness.


title:
Ab Initio Calculation of stressed Cesium Iodide lattices and resulting
  Surface Plasmon Resonance Peak shifts

abstract:
  Alkali halides like Cesium Iodide have received renewed attention as a
material with potential application as detector coating due to the appearance
of Surface Plasmon Resonance absorption peak in their UV-visible absorption
spectrum. The formation of Surface Plasmon Resonance peak has been traced to
the formation of Cesium metal clusters due to the aglomeration of color centers
embedded in Cesium Iodide background. This paper, based on experimental
observation that cubic Cesium Iodide experiences stress due to color centers
forming in the neighborhood and take up tetragonal lattice structure,
investigates the tetragonal Cesium Iodide's band structure and dielectric
constant using ab initio calculations. Both, the band-gap and dielectric
constant of Cesium Iodide, show a systematic variation with changing lattice
constant. While the band-gap is seen to strongly depend on the lattice
parameter `c', the dielectric constant's variation along `a' direction (${\rm
0.2~nm^{-1}}$) was found to be stronger than that along the `c' direction
(${\rm -2.5~nm^{-1}}$). The calculated dielectric constants were used as input
parameter for Gan model calculations of the extinction coefficient and
evaluation of Surface Plasmon Resonance peak position (${\rm \lambda_{max}}$).
A red-shift in ${\rm \lambda_{max}}$ was seen with increasing dielectric
constant that appears with stress acting on Cesium Iodide's lattice.


title:
Low-Frequency Electronic Noise in Exfoliated Quasi-1D TaSe3 van Der
  Waals Nanowires

abstract:
  We report results of investigation of the low-frequency electronic excess
noise in quasi-1D nanowires of TaSe3 capped with quasi-2D h-BN layers.
Semi-metallic TaSe3 is a quasi-1D van der Waals material with exceptionally
high breakdown current density. It was found that TaSe3 nanowires have lower
levels of the normalized noise spectral density, compared to carbon nanotubes
and graphene. The temperature-dependent measurements revealed that the
low-frequency electronic 1/f noise becomes the 1/f^2-type as temperature
increases to about 400 K, suggesting the onset of electromigration (f is the
frequency). Using the Dutta- Horn random fluctuation model of the electronic
noise in metals we determined that the noise activation energy for quasi-1D
TaSe3 nanowires is approximately E_P=1.0 eV. In the framework of the empirical
noise model for metallic interconnects, the extracted activation energy,
related to electromigration, is E_A=0.88 eV, consistent with that for Cu and Al
interconnects. Our results shed light on the physical mechanism of
low-frequency 1/f noise in quasi-1D van der Waals semi-metals and suggest that
such material systems have potential for ultimately downscaled local
interconnect applications.


title:
Inequalities Between Size, Mass, Angular Momentum, and Charge for
  Axisymmetric Bodies and the Formation of Trapped Surfaces

abstract:
  We establish inequalities relating the size of a material body to its mass,
angular momentum, and charge, within the context of axisymmetric initial data
sets for the Einstein equations. These inequalities hold in general without the
assumption of the maximal condition, and use a notion of size which is easily
computable. Moreover, these results give rise to black hole existence criteria
which are meaningful even in the time-symmetric case, and also include certain
boundary effects.


title: Optimal Capacity Allocation for Sampled Networked Systems

abstract:
  We consider the problem of estimating the states of weakly coupled linear
systems from sampled measurements. We assume that the total capacity available
to the sensors to transmit their samples to a network manager in charge of the
estimation is bounded above, and that each sample requires the same amount of
communication. Our goal is then to find an optimal allocation of the capacity
to the sensors so that the average estimation error is minimized. We show that
when the total available channel capacity is large, this resource allocation
problem can be recast as a strictly convex optimization problem, and hence
there exists a unique optimal allocation of the capacity. We further
investigate how this optimal allocation varies as the available capacity
increases. In particular, we show that if the coupling among the subsystems is
weak, then the sampling rate allocated to each sensor is nondecreasing in the
total sampling rate, and is strictly increasing if and only if the total
sampling rate exceeds a certain threshold.


title: Theory and simulation studies of self-assembly of helical particle

abstract:
  This is the unedited authors' version of Chapter 3 appearing in the following
book: Self-Assembly Systems: Theory and Simulations Ed. Li-Tang Yan John Wiley
& Sons, Ltd, Chichester, pp. 53-84 (2017)


title: DA White Dwarfs in the Kepler Field

abstract:
  We present 16 new, and confirm 7 previously identified, DA white dwarfs in
the Kepler field through ground-based spectroscopy with the Hale 200", Kitt
Peak 4-meter, and Bok 2.3-meter telescopes. Using atmospheric models we
determine their effective temperatures and surface gravities to constrain their
position with respect to the ZZ Ceti (DA pulsator) instability strip, and look
for the presence or absence of pulsation with Kepler's unprecedented
photometry. Our results are as follows: i) From our measurements of temperature
and surface gravity, 12 of the 23 DA white dwarfs from this work fall well
outside of the instability strip. The Kepler photometry available for 11 of
these WDs allows us to confirm that none are pulsating. One of these eleven
happens to be a presumed binary, KIC 11604781, with a period of ~5 days. ii)
The remaining 11 DA white dwarfs are instability strip candidates, potentially
falling within the current, empirical instability strip, after accounting for
uncertainties. These WDs will help constrain the strip's location further, as
eight are near the blue edge and three are near the red edge of the instability
strip. Four of these WDs do not have Kepler photometry, so ground-based
photometry is needed to determine the pulsation nature of these white dwarfs.
The remaining seven have Kepler photometry available, but do not show any
periodicity on typical WD pulsation timescales.


title: Non-Hermitian engineering of synthetic saturable absorbers

abstract:
  We introduce a new type of synthetic saturable absorbers based on quantum
inspired photonic arrays whose linear light transport characteristics can be
derived via bosonic algebra. We demonstrate that the interplay between optical
Kerr nonlinearity, interference effects and non-Hermiticity through radiation
loss leads to a nonlinear optical filtering response with two distinct regimes
of small and large optical transmissions. More interestingly, we show that the
boundary between these two regimes can be very sharp. The threshold optical
intensity that marks this abrupt "phase transition" and its steepness can be
engineered by varying the number of the guiding elements. The practical
feasibility of these structures as well as their potential applications in
laser systems and optical signal processing are also discussed.


title:
Exponential decay of connectivity and uniqueness in percolation on
  finite and infinite graphs

abstract:
  We give an upper bound for the uniqueness transition on an arbitrary locally
finite graph ${\cal G}$ in terms of the limit of the spectral radii $\rho\left[
H({\cal G}_t)\right]$ of the non-backtracking (Hashimoto) matrices for an
increasing sequence of subgraphs ${\cal G}_t\subset{\cal G}_{t+1}$ which
converge to ${\cal G}$. With the added assumption of strong local connectivity
for the oriented line graph (OLG) of ${\cal G}$, connectivity on any finite
subgraph ${\cal G}'\subset{\cal G}$ decays exponentially for $p<(\rho\left[
H({\cal G}^{\prime})\right])^{-1}$.


title: Niemeier Lattices in the Free Fermionic Heterotic-String Formulation

abstract:
  The spinor-vector duality was discovered in free fermionic constructions of
the heterotic-string in four dimensions. It played a key role in the
construction of heterotic-string models with an anomaly free extra $Z^\prime$
symmetry that may remain unbroken down to low energy scales. A generic
signature of the low scale string derived $Z^\prime$ model is via di-photon
excess that may be within reach of the LHC. A fascinating possibility is that
the spinor-vector duality symmetry is rooted in the structure of the
heterotic-string compactifications to two dimensions. The two dimensional
heterotic-string theories are in turn related to the so-called moonshine
symmetries that underlie the two dimensional compactifications. In this paper
we embark on exploration of this connection by the free fermionic formulation
to classify the symmetries of the two dimensional heterotic-string theories. We
use two complementary approaches in our classification. The first utilises a
construction which is akin to the one used in the spinor-vector duality.
Underlying this method is the triality property of $SO(8)$ representations. In
the second approach we use the free fermionic tools to classify the twenty four
dimensional Niemeier lattices.


title:
Bohr Hamiltonian with an energy dependent $\gamma$-unstable Coulomb-like
  potential

abstract:
  An exact analytical solution for the Bohr Hamiltonian with an energy
dependent Coulomb-like $\gamma$-unstable potential is presented. Due to the
linear energy dependence of the potential's coupling constant, the
corresponding spectrum in the asymptotic limit of the slope parameter resembles
the spectral structure of the spherical vibrator, however with a different
state degeneracy. The parameter free energy spectrum as well as the transition
rates for this case are given in closed form and duly compared with those of
the harmonic $U(5)$ dynamical symmetry. The model wave functions are found to
exhibit properties that can be associated to shape coexistence. A possible
experimental realization of the model is found in few medium nuclei with a very
low second $0^{+}$ state known to exhibit competing prolate, oblate and
spherical shapes.


title: Convergence rate of stochastic k-means

abstract:
  We analyze online and mini-batch k-means variants. Both scale up the widely
used Lloyd 's algorithm via stochastic approximation, and have become popular
for large-scale clustering and unsupervised feature learning. We show, for the
first time, that they have global convergence towards local optima at
$O(\frac{1}{t})$ rate under general conditions. In addition, we show if the
dataset is clusterable, with suitable initialization, mini-batch k-means
converges to an optimal k-means solution with $O(\frac{1}{t})$ convergence rate
with high probability. The k-means objective is non-convex and
non-differentiable: we exploit ideas from non-convex gradient-based
optimization by providing a novel characterization of the trajectory of k-means
algorithm on its solution space, and circumvent its non-differentiability via
geometric insights about k-means update.


title:
On representing the positive semidefinite cone using the second-order
  cone

abstract:
  The second-order cone plays an important role in convex optimization and has
strong expressive abilities despite its apparent simplicity. Second-order cone
formulations can also be solved more efficiently than semidefinite programming
in general. We consider the following question, posed by Lewis and Glineur,
Parrilo, Saunderson: is it possible to express the general positive
semidefinite cone using second-order cones? We provide a negative answer to
this question and show that the 3x3 positive semidefinite cone does not admit
any second-order cone representation. Our proof relies on exhibiting a sequence
of submatrices of the slack matrix of the 3x3 positive semidefinite cone whose
"second-order cone rank" grows to infinity. We also discuss the possibility of
representing certain slices of the 3x3 positive semidefinite cone using the
second-order cone.


title: Asymptotic direction for random walks in mixing random environments

abstract:
  We prove that every random walk in a uniformly elliptic random environment
satisfying the cone mixing condition and a non-effective polynomial
ballisticity condition with high enough degree has an asymptotic direction.


title: Chaos and complexity by design

abstract:
  We study the relationship between quantum chaos and pseudorandomness by
developing probes of unitary design. A natural probe of randomness is the
"frame potential," which is minimized by unitary $k$-designs and measures the
$2$-norm distance between the Haar random unitary ensemble and another
ensemble. A natural probe of quantum chaos is out-of-time-order (OTO)
four-point correlation functions. We show that the norm squared of a
generalization of out-of-time-order $2k$-point correlators is proportional to
the $k$th frame potential, providing a quantitative connection between chaos
and pseudorandomness. Additionally, we prove that these $2k$-point correlators
for Pauli operators completely determine the $k$-fold channel of an ensemble of
unitary operators. Finally, we use a counting argument to obtain a lower bound
on the quantum circuit complexity in terms of the frame potential. This
provides a direct link between chaos, complexity, and randomness.


title: Asymptotic structure of self-shrinkers

abstract:
  We show that each end of a noncompact self-shrinker in $\mathbb{R}^3$ of
finite topology is smoothly asymptotic to either a regular cone or a
self-shrinking round cylinder.


title:
Moment methods in energy minimization: New bounds for Riesz minimal
  energy problems

abstract:
  We use moment techniques to construct a converging hierarchy of optimization
problems to lower bound the ground state energy of interacting particle
systems. We approximate (from below) the infinite dimensional optimization
problems in this hierarchy by block diagonal semidefinite programs. For this we
develop the necessary harmonic analysis for spaces consisting of subsets of
another space, and we develop symmetric sum-of-squares techniques. We
numerically compute the second step of our hierarchy for Riesz s-energy
problems with five particles on the 2-dimensional unit sphere, where the s=1
case is the Thomson problem. This yields new numerically sharp bounds (up to
high precision) and suggests the second step of our hierarchy may be sharp
throughout a phase transition and may be universally sharp for 5-particles on
the unit sphere. This is the first time a 4-point bound has been computed for a
problem in discrete geometry.


title: Exotic hadron spectroscopy at the LHCb experiment

abstract:
  The LHCb experiment is designed to study the decays and properties of heavy
flavoured hadrons produced in the forward region from proton-proton collisions
at the CERN Large Hadron Collider. During Run 1, it has recorded the world's
largest data sample of beauty and charm hadrons, enabling precise studies into
the spectroscopy of such particles, including discoveries of new states and
measurements of their masses, widths and quantum numbers. An overview of recent
LHCb results in the area of exotic hadron spectroscopy is presented, focussing
on the discovery of the first pentaquark states in the $\Lambda_b^0 \to J/\psi
p K^-$ channel and a search for them in the related $\Lambda_b^0 \to J/\psi
p\pi^-$ mode. The LHCb non-confirmation of the D0 tetraquark candidate in the
$B_s^0\pi^+$ invariant mass spectrum is presented.


title:
The Discovery of Gas-Rich, Dusty Starbursts in Luminous Reddened Quasars
  at $z\sim2.5$ with ALMA

abstract:
  We present ALMA observations of cold dust and molecular gas in four
high-luminosity, heavily reddened (A$_{\rm{V}} \sim 2.5-6$ mag) Type 1 quasars
at $z\sim2.5$ with virial M$_{\rm{BH}} \sim 10^{10}$M$_\odot$, to test whether
dusty, massive quasars represent the evolutionary link between submillimetre
bright galaxies (SMGs) and unobscured quasars. All four quasars are detected in
both the dust continuum and in the $^{12}$CO(3-2) line. The mean dust mass is
6$\times$10$^{8}$M$_\odot$ assuming a typical high redshift quasar spectral
energy distribution (T=41K, $\beta$=1.95 or T=47K, $\beta$=1.6). The implied
star formation rates are very high - $\gtrsim$1000 M$_\odot$ yr$^{-1}$ in all
cases. Gas masses estimated from the CO line luminosities cover
$\sim$1-5$\times10^{10}$($\alpha_{\rm{CO}} / 0.8$)M$_\odot$ and the gas
depletion timescales are very short - $\sim5-20$Myr. A range of gas-to-dust
ratios is observed in the sample. We resolve the molecular gas in one quasar -
ULASJ2315$+$0143 ($z=2.561$) - which shows a strong velocity gradient over
$\sim$20 kpc. The velocity field is consistent with a rotationally supported
gas disk but other scenarios, e.g. mergers, cannot be ruled out at the current
resolution of these data. In another quasar - ULASJ1234+0907 ($z=2.503$) - we
detected molecular line emission from two millimetre bright galaxies within 200
kpc of the quasar, suggesting that this quasar resides in a significant
over-density. The high detection rate of both cold dust and molecular gas in
these sources, suggests that reddened quasars could correspond to an early
phase in massive galaxy formation associated with large gas reservoirs and
significant star formation.


title: Angular self-localization of impurities rotating in a bosonic bath

abstract:
  The existence of a self-localization transition in the polaron problem has
been under an active debate ever since Landau suggested it 83 years ago. Here
we reveal the self-localization transition for the rotational analogue of the
polaron -- the angulon quasiparticle. We show that, unlike for the polarons,
self-localization of angulons occurs at finite impurity-bath coupling already
at the mean-field level. The transition is accompanied by the
spherical-symmetry breaking of the angulon ground state and a discontinuity in
the first derivative of the ground-state energy. Moreover, the type of the
symmetry breaking is dictated by the symmetry of the microscopic impurity-bath
interaction, which leads to a number of distinct self-localized states. The
predicted effects can potentially be addressed in experiments on cold molecules
trapped in superfluid helium droplets and ultracold quantum gases, as well as
on electronic excitations in solids and Bose-Einstein condensates.

categories: cond-mat.quant-gas cond-mat.mes-hall cond-mat.other physics.atom-ph physics.chem-ph


title:
Surfactant and gravity dependent inertialess instability of two-layer
  Couette flows and its nonlinear saturation

abstract:
  A horizontal flow of two immiscible fluid layers with different densities,
viscosities and thicknesses, subject to vertical gravitational forces and with
an insoluble surfactant present at the interface, is investigated. The base
Couette flow is driven by the horizontal motion of the channel walls. Linear
and nonlinear stages of the (inertialess) surfactant and gravity dependent
long-wave instability are studied using the lubrication approximation, which
leads to a system of coupled nonlinear evolution equations for the interface
and surfactant disturbances. The linear stability is determined by an
eigenvalue problem for the normal modes. The growth rates and the amplitudes of
disturbances of the interface, surfactant, velocities, and pressures are found
analytically. For each wavenumber, there are two active normal modes. For each
mode, the instability threshold conditions in terms of the system parameters
are determined. In particular, it transpires that for certain parametric
ranges, even arbitrarily strong gravity cannot completely stabilize the flow.
The correlations of vorticity-thickness phase differences with instability,
present when the gravitational effects are neglected, are found to break down
when gravity is important. The physical mechanisms of instability for the two
modes are explained with vorticity playing no role in them. Unlike the
semi-infinite case that we previously studied, a small-amplitude nonlinear
saturation of the surfactant instability is possible in the absence of gravity.
For certain parametric ranges, the interface deflection is governed by a
decoupled Kuramoto-Sivashinsky equation, which provides a source term for a
linear convection-diffusion equation governing the surfactant concentration.
The full numerics confirm the prediction that, along with the interface, the
surfactant wave is chaotic, but the ratio of the two chaotic waves is constant.


title:
Stochastic Evolution Equations of Jump Type with Random Coefficients:
  Existence, Uniqueness and Optimal Control

abstract:
  We study a class of stochastic evolution equations of jump type with random
coefficients and its optimal control problem. There are three major
ingredients. The first is to prove the existence and uniqueness of the
solutions by continuous dependence theorem of solutions combining with the
parameter extension method. The second is to establish the stochastic maximum
principle and verification theorem for our optimal control problem by the
classic convex variation method and dual technique. The third is to represent
an example of a Cauchy problem for a controlled stochastic partial differential
equation with jumps which our theoretical results can solve.


title: $WWV$ $(V=\gamma,Z)$ vertex in the Georgi-Machacek model

abstract:
  The CP-even static form factors $\Delta\kappa'_V$ and $\Delta Q_V$
($V=\gamma,\, Z$) associated with the $WWV$ vertex are studied in the context
of the Georgi-Machacek model (GMM), which predicts nine new scalar bosons
accommodated in a singlet, a triplet and a fiveplet. General expressions for
the one-loop contributions to $\Delta\kappa'_V$ and $\Delta Q_V$ arising from
neutral, singly and doubly charged scalar bosons are obtained in terms of both
parametric integrals and Passarino-Veltman scalar functions, which can be
numerically evaluated. It is found that the GMM yields 15 (28) distinct
contributions to $\Delta\kappa'_\gamma$ and $\Delta Q_\gamma$
($\Delta\kappa'_Z$ and $\Delta Q_Z$), though several of them are naturally
suppressed. A numerical analysis is done in the region of parameter space still
consistent with current experimental data and it is found that the largest
contributions to $\Delta\kappa'_V$ arise from Feynman diagrams with two
nondegenerate scalar bosons in the loop, with values of the order of
$a=g^2/(96\pi^2)$ reached when there is a large splitting between the masses of
these scalar bosons. As for $\Delta Q_V$, it reaches values as large as
$10^{-2}a$ for the lightest allowed scalar bosons, but it decreases rapidly as
one of the masses of the scalar bosons becomes large. Among the new
contributions of the GMM to the $\Delta\kappa'_V$ and $\Delta Q_V$ form factors
are those induced by the $H_5^\pm W^\mp Z$ vertex, which arises at the
tree-level and is a unique prediction of this model.


title:
Boundary value problem for the time-fractional telegraph equation with
  Caputo derivatives

abstract:
  In this paper the Green formula for the operator of fractional
differentiation in Caputo sense is proved. By using this formula the integral
representation of all regular in a rectangular domains solutions is obtained in
the form of the Green formula for operator generating the time-fractional
telegraph equation. The unique solutions of the initial-boundary value problem
with boundary conditions of first kind is constructed. The proposed approach
can be used to study the more general evolution FPDE as well as ODE with Caputo
derivatives.


abstract:
  We present a short review of the current and recent development in the field
of superfluid 3He and 4He. The review is based on the topics discussed at the
NSF sponsoredWorkshop on Grand Challenges in Quantum Fluids and Solids chaired
by Moses Chan from Pennsylvania State University and held at University of
Buffalo in August, 2015.


title: Pulse-noise approach for classical spin systems

abstract:
  For systems of classical spins interacting with the bath via damping and
thermal noise, the approach is suggested to replace the white noise by a pulse
noise acting at regular time intervals $\Delta t$, within which the system
evolves conservatively. The method is working well in the typical case of a
small dimensionless damping constant $\lambda$ and allows a considerable
speed-up of computations by using high-order numerical integrators with a large
time step $\delta t$ (up to a fraction of the precession period), while keeping
$\delta t\ll\Delta t$ to reduce the relative contribution of noise-related
operations. In cases when precession can be discarded, $\delta t$ can be
increased up to a fraction of the relaxation time $\propto1/\lambda$ that leads
to a further speed-up. This makes equilibration speed comparable with that of
Metropolis Monte Carlo. The pulse-noise approach is tested on single-spin and
multi-spin models.


title: Logarithmic price of buffer downscaling on line metrics

abstract:
  We consider the reordering buffer problem on a line consisting of n
equidistant points. We show that, for any constant delta, an (offline)
algorithm that has a buffer (1-delta) k performs worse by a factor of Omega(log
n) than an offline algorithm with buffer k. In particular, this demonstrates
that the O(log n)-competitive online algorithm MovingPartition by Gamzu and
Segev (ACM Trans. on Algorithms, 6(1), 2009) is essentially optimal against any
offline algorithm with a slightly larger buffer.


title:
Nodal solutions for fourth order elliptic equations with critical
  exponent on compact manifolds

abstract:
  Using a variational method we prove the existence of nodal solutions to
prescribed scalar Q- curvature type equations on compact Riemannian manifolds
with boundary; these equations are fourth-order elliptic equations with
critical Sobolev growth .


title:
Long-period suspended silicon Bragg grating filter for hybrid near- and
  mid-infrared operation

abstract:
  The large transparency window of silicon, covering the 1.1 um 8 um wavelength
range, makes it a promising platform for the implementation of
photothermal-based absorption spectrometers. These devices indirectly sense
absorption in the mid-infrared (MIR) by using near-infrared (NIR) wavelengths,
thereby enabling the realization of MIR absorption spectrometers without the
need for MIR photodetectors. Nevertheless, due to their comparatively large
index contrast and cross-sections, MIR Si strip waveguides are multi-mode at
NIR wavelengths, hindering device implementation. Here we present, for the
first time, an integrated Bragg grating waveguide filter for hybrid near- and
mid-infrared operation. Specifically, the filter is implemented in a
single-etch suspended silicon corrugated waveguide with an effectively
single-mode operation in NIR region for a waveguide cross-section as large as
0.5 um x 1.1 um. At the same time, the waveguide supports single-mode
propagation in MIR region. We demonstrate a long-period waveguide Bragg grating
yielding a sharp third-order Bragg resonance for the fundamental waveguide mode
and radiating the higher order modes. We experimentally demonstrate a notch
filter with a 4nm bandwidth and 40 dB extinction ratio with a
temperature-dependent Bragg wavelength shift of 70pm/K.


title: Fractional Calabi-Yau Categories from Landau-Ginzburg Models

abstract:
  We give criteria for the existence of a Serre functor on the derived category
of a gauged Landau-Ginzburg model. This is used to provide a general theorem on
the existence of an admissible (fractional) Calabi-Yau subcategory of a gauged
Landau-Ginzburg model and a geometric context for crepant categorical
resolutions. We explicitly describe our framework in the toric setting. As a
consequence, we generalize several theorems and examples of Orlov and
Kuznetsov, ending with new examples of semi-orthogonal decompositions
containing (fractional) Calabi-Yau categories.


title: Power Control for Packet Streaming with Head-of-Line Deadlines

abstract:
  We consider a mathematical model for streaming media packets (as the
motivating key example) from a transmitter buffer to a receiver over a wireless
link while controlling the transmitter power (hence, the packet/job processing
rate). When each packet comes to the head-of-line (HOL) in the buffer, it is
given a deadline $D$ which is the maximum number of times the transmitter can
attempt retransmission in order to successfully transmit the packet. If this
number of transmission attempts is exhausted, the packet is ejected from the
buffer and the next packet comes to the HOL. Costs are incurred in each time
slot for holding packets in the buffer, expending transmitter power, and
ejecting packets which exceed their deadlines. We investigate how transmission
power should be chosen so as to minimize the total cost of transmitting the
items in the buffer. We formulate the optimal power control problem in a
dynamic programming framework and then hone in on the special case of fixed
interference. For this special case, we are able to provide a precise analytic
characterization of how the power control should vary with the backlog and how
the power control should react to approaching deadlines. In particular, we show
monotonicity results for how the transmitter should adapt power levels to the
backlog and approaching deadlines. We leverage these analytic results from the
special case to build a power control scheme for the general case. Monte Carlo
simulations are used to evaluate the performance of the resulting power control
scheme as compared to the optimal scheme. The resulting power control scheme is
sub-optimal but it provides a low-complexity approximation of the optimal power
control. Simulations show that our proposed schemes outperform benchmark
algorithms. We also discuss applications of the model to other practical
operational scenarios.


title: On the monodromy group of the family of smooth plane curves

abstract:
  We consider the space of smooth complex projective plane curves of degree d.
Defined over this is the tautological family of plane curves, and hence there
is a monodromy representation into the mapping class group of the fiber. We
show two results concerning this monodromy group. First, we show that the
presence of an invariant known as a "n-spin structure" constrains the image in
ways not predicted by previous work of Beauville. Second, we show that for
degree d=5, our invariant is the only obstruction for a mapping class to be
contained in the image. This requires combining the algebro-geometric work of
L\"onne with Johnson's theory of the Torelli subgroup of the mapping class
group.


title: Electron correlation by polarization of interacting densities

abstract:
  Coulomb interactions that occur in electronic structure calculations are
correlated by allowing basis function components of the interacting densities
to polarize, thereby reducing the magnitude of the interaction. Exchange
integrals of molecular orbitals are not correlated. The modified Coulomb
interactions are used in single-determinant or configuration interaction
calculations. The objective is to account for dynamical correlation effects
without explicitly introducing higher spherical harmonic functions into the
molecular orbital basis. Molecular orbital densities are decomposed into a
distribution of spherical components that conserve the charge and each of the
interacting components is considered as a two-electron wavefunction embedded in
the system acted on by an average field Hamiltonian plus . A method of avoiding
redundancy is described. Applications to atoms, negative ions and molecules
representing different types of bonding and spin states are discussed.


title: Making Mainstream Synthesizers with Csound

abstract:
  For more than the past twenty years, Csound has been one of the leaders in
the world of the computer music research, implementing innovative synthesis
methods and making them available beyond the academic environments from which
they often arise, and into the hands of musicians and sound designers
throughout the world. In its present state, Csound offers an efficient
environment for sound experimentation, allowing the user to work with almost
any known sound synthesis or signal processing method through its vast
collection of ready-made opcodes. But despite all this potential, the shared
resource of Csound instruments still lacks quality reproductions of well-known
synthesizers; even with its ability to generate commercial standard user
interfaces and with the possibility to compile Csound instruments in such as
fashion so that they can be used with no knowledge of Csound code. To fill this
gap, the authors have implemented two commercial-style synthesizers as VST
plug-ins using the Csound front-end "Cabbage". This paper describes their
architecture and some of the Csound specific challenges involved in the
development of fully featured synthesizers.


title:
A Simple Analytical Model of Coupled Single Flow Channel over Porous
  Electrode in Vanadium Redox Flow Battery with Serpentine Flow Channel

abstract:
  A simple analytical model of a layered system comprised of a single passage
of a serpentine flow channel and a parallel underlying porous electrode (or
porous layer) is proposed. This analytical model is derived from Navier-Stokes
motion in the flow channel and Darcy-Brinkman model in the porous layer. The
continuities of flow velocity and normal stress are applied at the interface
between the flow channel and the porous layer. The effects of the inlet
volumetric flow rate, thickness of the flow channel and thickness of a typical
carbon fiber paper porous layer on the volumetric flow rate within this porous
layer are studied. The maximum current density based on the electrolyte
volumetric flow rate is predicted, and found to be consistent with reported
numerical simulation. It is found that, for a mean inlet flow velocity of 33.3
cm s-1, the analytical maximum current density is estimated to be 377 mA cm-2,
which compares favorably with experimental result reported by others of ~400 mA
cm-2.


title: An interleaver design for polar codes over slow fading channels

abstract:
  We consider the problem of using polar codes over slow fading wireless
channels. For design, we focus on a parallel slow fading channel with 2 blocks,
and polar codes with rate <= 1/2. Motivated by Arikan's systematic polar code
construction, we propose an interleaver design for a general polar code. The
interleaver comprises of using the bit reversal of the order of polarized bit
channels. This interleaver is called a diversity interleaver. In addition to
the diversity interleaver, a diversity polar code is proposed to further
increase the diversity gain.
  The proposed designs are evaluated via link simulations for AWGN and fading
channels. The simulation results show a performance close to the outage
probability (within 2 dB) and significant gains over using a random
interleaver.


title:
Canonical Quantization, Quasi-Hermiticity, Observables and the
  Construction of Complete Basis Sets

abstract:
  We consider the problem of designing a variety of "system guided" basis sets
for quantum mechanical anharmonic oscillators. Using ideas based on
supersymmetric quantum mechanics, we design canonical transformations of the
usual position and momentum to generate generalized "Cartesian-like positions,
W and momenta, p_W" with unit Poisson brackets. These are quantized following
Dirac, leading to an infinite family of potential "operator observables". The
fundamental issue is that all but one of the operators are not Hermitian
(formally self-adjoint) in the original position representation. We show that
the resulting operators are "quasi-Hermitian" relative to the x-representation
and that all are Hermitian in the W-representation. Depending on how one treats
the Jacobian of the canonical transformation in the expression for the
classical momentum, p_W, quantization yields a) continuous mutually unbiased
bases (MUB) b) orthogonal bases (with Dirac delta normalization) c)
biorthogonal bases (with Dirac delta normalization) d) new W-harmonic
oscillators yielding standard orthonormal bases (as functions of W) and
associated coherent states. The MUB include W-generalized Fourier transform
kernels whose eigenvectors are the W-harmonic oscillator eigenstates, with the
spectrum (p/m i, p/m i). The W, p_W satisfy the uncertainty product relation:
Delta-W * Delta-p_W gte 1/2.


title: Algebraic approach to form factors in the complex sinh-Gordon theory

abstract:
  We study form factors of the quantum complex sinh-Gordon theory in the
algebraic approach. In the case of exponential fields the form factors can be
obtained from the known form factors of the $Z_N$-symmetric Ising model. The
algebraic construction also provides an Ansatz for form factors of descendant
operators. We obtain generating functions of such form factors and establish
their main properties: the cluster factorization and reflection equations.


title: Local probe of single phonon dynamics in warm ion crystals

abstract:
  The detailed characterization of non-trivial coherence properties of
composite quantum systems of increasing size is an indispensable prerequisite
for scalable quantum computation, as well as for understanding of
nonequilibrium many-body physics. Here we show how autocorrelation functions in
an interacting system of phonons as well as the quantum discord between
distinct degrees of freedoms can be extracted from a small controllable part of
the system. As a benchmark, we show this in chains of up to 42 trapped ions, by
tracing a single phonon excitation through interferometric measurements of only
a single ion in the chain. We observe the spreading and partial refocusing of
the excitation in the chain, even on a background of thermal excitations. We
further show how this local observable reflects the dynamical evolution of
quantum discord between the electronic state and the vibrational degrees of
freedom of the probe ion.


title: A Dirichlet type problem for complex polyharmonic functions

abstract:
  We extend holomorphically polyharmonic functions on a real ball to a complex
set being the union of rotated balls. We solve a Dirichlet type problem for
complex polyharmonic functions with the boundary condition given on the union
of rotated spheres.


title: Probabilistic Dimensionality Reduction via Structure Learning

abstract:
  We propose a novel probabilistic dimensionality reduction framework that can
naturally integrate the generative model and the locality information of data.
Based on this framework, we present a new model, which is able to learn a
smooth skeleton of embedding points in a low-dimensional space from
high-dimensional noisy data. The formulation of the new model can be
equivalently interpreted as two coupled learning problem, i.e., structure
learning and the learning of projection matrix. This interpretation motivates
the learning of the embedding points that can directly form an explicit graph
structure. We develop a new method to learn the embedding points that form a
spanning tree, which is further extended to obtain a discriminative and compact
feature representation for clustering problems. Unlike traditional clustering
methods, we assume that centers of clusters should be close to each other if
they are connected in a learned graph, and other cluster centers should be
distant. This can greatly facilitate data visualization and scientific
discovery in downstream analysis. Extensive experiments are performed that
demonstrate that the proposed framework is able to obtain discriminative
feature representations, and correctly recover the intrinsic structures of
various real-world datasets.


title: Honeycomb Schroedinger operators in the strong binding regime

abstract:
  In this article, we study the Schr\"odinger operator for a large class of
periodic potentials with the symmetry of a hexagonal tiling of the plane. The
potentials we consider are superpositions of localized potential wells,
centered on the vertices of a regular honeycomb structure corresponding to the
single electron model of graphene and its artificial analogues. We consider
this Schr\"odinger operator in the regime of strong binding, where the depth of
the potential wells is large. Our main result is that for sufficiently deep
potentials, the lowest two Floquet-Bloch dispersion surfaces, when
appropriately rescaled, converge uniformly to those of the two-band
tight-binding model (Wallace, 1947). Furthermore, we establish as corollaries,
in the regime of strong binding, results on (a) the existence of spectral gaps
for honeycomb potentials that break $\mathcal{P}\mathcal{T}$ symmetry and (b)
the existence of topologically protected edge states -- states which propagate
parallel to and are localized transverse to a line-defect or "edge" - for a
large class of rational edges, and which are robust to large localized
perturbations of the edge. We believe that the ideas of this article may be
applicable in other settings for which a tight-binding model emerges in an
extreme parameter limit.

categories: math-ph cond-mat.mes-hall cond-mat.mtrl-sci math.AP math.MP


title: Open ASEP in the Weakly Asymmetric Regime

abstract:
  We consider ASEP on a bounded interval and on a half line with sources and
sinks. On the full line, Bertini and Giacomin proved convergence under weakly
asymmetric scaling of the height function to the solution of the KPZ equation.
We prove here that under similar weakly asymmetric scaling of the sources and
sinks as well, the bounded interval ASEP height function converges to the KPZ
equation on the unit interval with Neumann boundary conditions on both sides
(different parameter for each side); and likewise for the half line ASEP to KPZ
on a half line. This result can be interpreted as showing that the KPZ equation
arises at the triple critical point (maximal current / high density / low
density) of the open ASEP.


title: The homomorphism threshold of $\{C_3, C_5\}$-free graphs

abstract:
  We determine the structure of $\{C_3, C_5\}$-free graphs with $n$ vertices
and minimum degree larger than $n/5$: such graphs are homomorphic to the graph
obtained from a $(5k - 3)$-cycle by adding all chords of length $1$ mod $5$,
for some $k$. This answers a question of Messuti and Schacht. We deduce that
the homomorphism threshold of $\{C_3, C_5\}$-free graphs is $1/5$, thus
answering a question of Oberkampf and Schacht.


title: Particle Creation in Bouncing Cosmologies

abstract:
  We investigate scalar particle creation in a set of bouncing models where the
bounce occurs due to quantum cosmological effects described by the
Wheeler-DeWitt equation. The scalar field can be either conformally or
minimally coupled to gravity, and it can be massive or massless, without self
interaction. The analysis is made for models containing a single radiation
fluid, and for the more realistic case of models containing the usual observed
radiation and dust fluids, which can fit most of the observed features of our
Universe, including an almost scale invariant power spectrum of scalar
cosmological perturbations. In the conformal coupling case, the particle
production is negligible. In the minimal coupling case, for massive particles,
the results point to the same physical conclusion within observational
constraints: particle production is most important at the bounce energy scale,
and it is not sensitive neither to its mass nor whether there is dust in the
background model. The only caveat is the case where the particle mass is larger
than the bounce energy scale. On the other hand, the energy density of produced
massive particles depend on their masses and the energy scale of the bounce.
For very large masses and deep bounces, this energy density may overcome that
of the background. In the case of massless particles, the energy density of
produced particles can become comparable to the background energy density only
for bounces occurring at energy scales comparable to the Planck scale or above,
which lies beyond the scope of this paper: we expect that the simple
Wheeler-DeWitt approach we are using should be valid only at scales some few
orders of magnitude below the Planck energy. Nevertheless, in the case in which
dust is present, there is an infrared divergence, which becomes important only
for scales much larger than today's Hubble radius.


title: Super-Diffusive Gas Recovery from Nanopores

abstract:
  Understanding the recovery of gas from reservoirs featuring pervasive
nanopores is essential for effective shale gas extraction. Classical theories
cannot accurately predict such gas recovery and many experimental observations
are not well understood. Here we report molecular simulations of the recovery
of gas from single nanopores, explicitly taking into account molecular gas-wall
interactions. We show that, in very narrow pores, the strong gas-wall
interactions are essential in determining the gas recovery behavior both
quantitatively and qualitatively. These interactions cause the total diffusion
coefficients of the gas molecules in nanopores to be smaller than those
predicted by kinetic theories, hence slowing down the rate of gas recovery.
These interactions also lead to significant adsorption of gas molecules on the
pore walls. Because of the desorption of these gas molecules during gas
recovery, the gas recovery from the nanopore does not exhibit the usual
diffusive scaling law (i.e., the accumulative recovery scales as $R \sim
t^{1/2}$ but follows a super-diffusive scaling law $R \sim t^n$ ($n>0.5$),
which is similar to that observed in some field experiments. For the system
studied here, the super-diffusive gas recovery scaling law can be captured well
by continuum models in which the gas adsorption and desorption from pore walls
are taken into account using the Langmuir model.


title:
Approximations of the Densest k-Subhypergraph and Set Union Knapsack
  problems

abstract:
  For any given $\epsilon>0$ we provide an algorithm for the Densest
$k$-Subhypergraph Problem with an approximation ratio of at most
$O(n^{\theta_m+2\epsilon})$ for
$\theta_m=\frac{1}{2}m-\frac{1}{2}-\frac{1}{2m}$ and run time at most
$O(n^{m-2+1/\epsilon})$, where the hyperedges have at most $m$ vertices. We use
this result to give an algorithm for the Set Union Knapsack Problem with an
approximation ratio of at most $O(n^{\alpha_m+\epsilon})$ for
$\alpha_m=\frac{2}{3}[m-1-\frac{2m-2}{m^2+m-1}]$ and run time at most
$O(n^{5(m-2)+9/\epsilon})$, where the subsets have at most $m$ elements. The
author is not aware of any previous results on the approximation of either of
these two problems.


title: Partial Procedural Geometric Model Fitting for Point Clouds

abstract:
  Geometric model fitting is a fundamental task in computer graphics and
computer vision. However, most geometric model fitting methods are unable to
fit an arbitrary geometric model (e.g. a surface with holes) to incomplete
data, due to that the similarity metrics used in these methods are unable to
measure the rigid partial similarity between arbitrary models. This paper hence
proposes a novel rigid geometric similarity metric, which is able to measure
both the full similarity and the partial similarity between arbitrary geometric
models. The proposed metric enables us to perform partial procedural geometric
model fitting (PPGMF). The task of PPGMF is to search a procedural geometric
model space for the model rigidly similar to a query of non-complete point set.
Models in the procedural model space are generated according to a set of
parametric modeling rules. A typical query is a point cloud. PPGMF is very
useful as it can be used to fit arbitrary geometric models to non-complete
(incomplete, over-complete or hybrid-complete) point cloud data. For example,
most laser scanning data is non-complete due to occlusion. Our PPGMF method
uses Markov chain Monte Carlo technique to optimize the proposed similarity
metric over the model space. To accelerate the optimization process, the method
also employs a novel coarse-to-fine model dividing strategy to reject
dissimilar models in advance. Our method has been demonstrated on a variety of
geometric models and non-complete data. Experimental results show that the
PPGMF method based on the proposed metric is able to fit non-complete data,
while the method based on other metrics is unable. It is also shown that our
method can be accelerated by several times via early rejection.


title: Augmented Index and Quantum Streaming Algorithms for DYCK(2)

abstract:
  We show how two recently developed quantum information theoretic tools can be
applied to obtain lower bounds on quantum information complexity. We also
develop new tools with potential for broader applicability, and use them to
establish a lower bound on the quantum information complexity for the Augmented
Index function on an easy distribution. This approach allows us to handle
superpositions rather than distributions over inputs, the main technical
challenge faced previously. By providing a quantum generalization of the
argument of Jain and Nayak [IEEE TIT'14], we leverage this to obtain a lower
bound on the space complexity of multi-pass, unidirectional quantum streaming
algorithms for the DYCK(2) language.


title:
A new smoothness result for Caputo-type fractional ordinary differential
  equations

abstract:
  We present a new smoothness result for Caputo-type fractional ordinary
differential equations, which reveals that, subtracting a non-smooth function
that can be obtained by the information available, a non-smooth solution
belongs to $ C^m $ for some positive integer $ m $.


title: Windowed Green Function Method for Nonuniform Open-Waveguide Problems

abstract:
  This contribution presents a novel Windowed Green Function (WGF) method for
the solution of problems of wave propagation, scattering and radiation for
structures which include open (dielectric) waveguides, waveguide junctions, as
well as launching and/or termination sites and other nonuniformities. Based on
use of a "slow-rise" smooth-windowing technique in conjunction with free-space
Green functions and associated integral representations, the proposed approach
produces numerical solutions with errors that decrease faster than any negative
power of the window size. The proposed methodology bypasses some of the most
significant challenges associated with waveguide simulation. In particular the
WGF approach handles spatially-infinite dielectric waveguide structures without
recourse to absorbing boundary conditions, it facilitates proper treatment of
complex geometries, and it seamlessly incorporates the open-waveguide character
and associated radiation conditions inherent in the problem under
consideration. The overall WGF approach is demonstrated in this paper by means
of a variety of numerical results for two-dimensional open-waveguide
termination, launching and junction problems.


title:
Spin blockade and coherent dynamics of high-spin states in a
  three-electron double quantum dot

abstract:
  Asymmetry in a three-electron double quantum dot (DQD) allows spin blockade,
when spin-3/2 (quadruplet) states and spin-1/2 (doublet) states have different
charge configurations. We have observed this DQD spin blockade near the
(1,2)-(2,1) charge transition using a pulsed-gate technique and a charge
sensor. We then use this spin blockade to detect Landau-Zener-St\"uckelberg
(LZS) interference and coherent oscillations between the spin quadruplet and
doublet states. Such studies add to our understandings of coherence and control
properties of three-spin states in a double dot, which in turn would benefit
the explorations into various qubit encoding schemes in semiconductor
nanostructures.


title:
Superoutburst of WZ Sge-type Dwarf Nova Below the Period Minimum:
  ASASSN-15po

abstract:
  We report on a superoutburst of a WZ Sge-type dwarf nova (DN), ASASSN-15po.
The light curve showed the main superoutburst and multiple rebrightenings. In
this outburst, we observed early superhumps and growing (stage A) superhumps
with periods of 0.050454(2) and 0.051809(13) d, respectively. We estimated that
the mass ratio of secondary to primary ($q$) is 0.0699(8) by using $P_{\rm
orb}$ and a superhump period $P_{\rm SH}$ of stage A. ASASSN-15po [$P_{\rm orb}
\sim$ 72.6 min] is the first DN with the orbital period between 67--76 min.
Although the theoretical predicted period minimum $P_{\rm min}$ of
hydrogen-rich cataclysmic variables (CVs) is about 65--70 min, the
observational cut-off of the orbital period distribution at 80 min implies that
the period minimum is about 82 min, and the value is widely accepted. We
suggest the following four possibilities: the object is (1) a theoretical
period minimum object (2) a binary with a evolved secondary (3) a binary with a
metal-poor (Popullation II) seconday (4) a binary which was born with a
brown-dwarf donor below the period minimum.


title: Pigmy resonances, transfer, and separable potentials

abstract:
  In this contribution we make a short review of recent progress on topics of
current interest in nuclear physics and nuclear astrophysics. In particular, we
discuss a re-analysis of the extraction of the dipole response of the pigmy
resonance in $^{68}$Ni based on a continuum discretized coupled-channels
calculation in relativistic Coulomb excitation experiments. We also discuss the
forthcoming progresses made by our group on the Alt-Sandhas-Grassberber
approach to (d,p) reactions and future expectations. The role of separable
potentials in solving such equations with a test case based on applications of
such potentials to phase-shift analysis is also presented.


title:
Cocycle rigidity of partially hyperbolic abelian actions with almost
  rank one factors

abstract:
  We extend the recent progress on the cocycle rigidity of partially hyperbolic
homogeneous abelian actions to the setting with rank 1 factors in the universal
cover. The method of proof relies on the periodic cycle functional and analysis
of the cycle structure, but uses a new argument to give vanishing.


title: The Adherence Order on Renner-Coxeter Monoids

abstract:
  Building upon the previous Renner-Coxeter system of work by Eddy Godelle we
introduce the familiar Renner monoid structure of the Adherence order. The
Green's relations of the system are then considered in relation to the
Adherence order and in the finite case maximum and minimum elements in each
equivalence class are distinguished and studied.


title:
Diffractive charmonium spectrum in high energy collisions in the basis
  light-front quantization approach

abstract:
  Using the charmonium light-front wavefunctions obtained by diagonalizing an
effective Hamiltonian with the one-gluon exchange interaction and a confining
potential inspired by light-front holography in the basis light-front
quantization formalism, we compute production of charmonium states in
diffractive deep inelastic scattering and ultra-peripheral heavy ion collisions
within the dipole picture. Our method allows us to predict yields of all vector
charmonium states below the open flavor thresholds in high-energy deep
inelastic scattering, proton-nucleus and ultra-peripheral heavy ion collisions,
without introducing any new parameters in the light-front wavefunctions. The
obtained charmonium cross section is in reasonable agreement with experimental
data at HERA, RHIC and LHC. We observe that the cross-section ratio
$\sigma_{\Psi(2s)}/\sigma_{J/\Psi}$ reveals significant independence of model
parameters.


title:
On the equivariant Betti numbers of symmetric definable sets: vanishing,
  bounds and algorithms

abstract:
  Let $\mathrm{R}$ be a real closed field. We prove that for any fixed $d$, the
equivariant rational cohomology groups of closed symmetric semi-algebraic
subsets of $\mathrm{R}^k$ defined by polynomials of degrees bounded by $d$
vanishes in dimensions $d$ and larger. This vanishing result is tight. Using a
new geometric approach we also prove an upper bound of $d^{O(d)} s^d k^{\lfloor
d/2 \rfloor-1} $ on the equivariant Betti numbers of closed symmetric
semi-algebraic subsets of $\mathrm{R}^k$ defined by quantifier-free formulas
involving $s$ symmetric polynomials of degrees bounded by $d$, where $1 < d \ll
s,k$. This bound is tight up to a factor depending only on $d$. These results
significantly improve upon those obtained previously which were proved using
different techniques. Our new methods are quite general, and also yield bounds
on the equivariant Betti numbers of certain special classes of symmetric
definable sets (definable sets symmetrized by pulling back under symmetric
polynomial maps of fixed degree) in arbitrary o-minimal structures over
$\mathrm{R}$. Finally, we utilize our new approach to obtain an algorithm with
polynomially bounded complexity for computing these equivariant Betti numbers.
In contrast, the problem of computing the ordinary Betti numbers of (not
necessarily symmetric) semi-algebraic sets is considered to be an intractable
problem, and all known algorithms for this problem have doubly exponential
complexity.


title:
Robust and stable delay interferometers with application to
  $d$-dimensional time-frequency quantum key distribution

abstract:
  We investigate experimentally a cascade of temperature-compensated
unequal-path interferometers that can be used to measure frequency states in a
high-dimensional quantum distribution system. In particular, we demonstrate
that commercially-available interferometers have sufficient environmental
isolation so that they maintain an interference visibility greater than 98.5\%
at a wavelength of 1550 nm over extended periods with only moderate passive
control of the interferometer temperature ($< \pm0.50 ^{\circ}$C).
Specifically, we characterize two interferometers that have matched delays: one
with a free-spectral range of 2.5 GHz, and the other with 1.25 GHz. We find
that the relative path of these interferometers drifts less than 3~nm over a
period of one hour during which the temperature fluctuates by $<\pm$0.10
$^{\circ} $C. When we purposely heat the interferometers over a temperature
range of 20-50 $^{\circ}$C, we find that the temperature sensitivity is
different for each interferometer, likely due to slight manufacturing errors
during the temperature compensation procedure. Over this range, we measure a
path-length shift of 26 $\pm$ 9 nm/$^{\circ} $C for the 2.5 GHz interferometer.
For the 1.25 GHz interferometer, the path-length shift is nonlinear and is
locally equal to zero at a temperature of 37.1 $^{\circ}$C and is 50 $\pm$ 17
nm/$^{\circ} $C at 22 $^{\circ}$C. With these devices, we realize a cascade of
1.25 GHz and 2.5 GHz interferometers to measure four-dimensional classical
frequency states created by modulating a stable and continuous-wave laser. We
observe a visibility $>99\%$ over an hour, which is mainly limited by our
ability to precisely generate these states. Overall, our results indicate that
these interferometers are well suited for realistic time-frequency quantum
distribution protocols.


title: Families of 0-dimensional submanifolds on supercurves

abstract:
  In the present paper we prove that the Hilbert scheme of 0-dimensional
subspaces on supercurves of dimension $(1|1)$ exists and it is smooth. We show
that the Hilbert scheme is not split in general.


title: Dark-like states for the multi-qubit and multi-photon Rabi models

abstract:
  There are well-known dark states in the even-qubit Dicke models, which are
the products of the two-qubit singlets and a Fock state, where the qubits are
decoupled from the photon field. These spin singlets can be used to store
quantum correlations since they preserve entanglement even under dissipation,
driving and dipole-dipole interactions. One of the features for these dark
states is that their eigenenergies are independent of the qubitphoton coupling
strength. We have obtained a novel kind of dark-like states for the multi-qubit
and multi-photon Rabi models, whose eigenenergies are also constant in the
whole coupling regime. Unlike the dark states, the qubits and photon field are
coupled in the dark-like states. Furthermore, the photon numbers are bounded
from above commonly at 1, which is different from that for the one-qubit case.
The existence conditions of the dark-like states are simpler than exact
isolated solutions, and may be fine tuned in experiments. While the
single-qubit and multi-photon Rabi model is well-defined only if the photon
number $M\leq2$ and the coupling strength is below a certain critical value,
the dark-like eigenstates for multi-qubit and multiphoton Rabi model still
exist, regardless of these constraints. In view of these properties of the
dark-like states, they may find similar applications like "dark states" in
quantum information.


title:
New Algorithms for Maximizing Cellular Wireless Network Energy
  Efficiency

abstract:
  In this paper, we aim to maximize the energy efficiency of cellular wireless
networks. Specifically, we address the power allocation problem in multi-cell
multi-carrier systems. Considering realistic base station power consumption
models, we formulate a network-wide energy efficiency maximization problem.
Using tools from fractional programming, we cast this problem in the framework
of bi-criterion optimization where rate maximization and power minimization are
weighted accordingly. Interference pricing mechanism is applied to reduce the
intercell interference and to achieve a higher network performance. We
decompose the main problem into subproblems via dual decomposition. These
subproblems are independently solved per sector using limited information
exchange between base stations. We first derive our expressions and present
algorithms for the single-tier networks. Then, we extend our analysis to
two-tier networks where picocell base stations are deployed to improve the
network performance and reduce the link distances. Lastly, we extend our
framework and include the quality-of-service constraints.We obtain closed-form
expressions for the power level updates which are determined by the multi-level
water-filling algorithm, or, as it is sometimes called as, the modified
waterfilling algorithm. Based on our simulation results, we demonstrate that
the proposed algorithms can outperform the benchmark approaches in terms of
energy efficiency by a factor of 2.7.


title: VLBA Calibrator Survey 9 (VCS-9)

abstract:
  The goals, current status, and preliminary results of the VLBA Calibration
Survey VCS-9 are discussed.


title:
On the structure and statistical theory of turbulence of extended
  magnetohydrodynamics

abstract:
  Recent progress regarding the noncanonical Hamiltonian formulation of
extended magnetohydrodynamics (XMHD), a model with Hall drift and electron
inertia, is summarized. The advantages of the Hamiltonian approach are invoked
to study some general properties of XMHD turbulence, and to compare them
against their ideal MHD counterparts. For instance, the helicity flux transfer
rates for XMHD are computed, and Liouville's theorem for this model is also
verified. The latter is used, in conjunction with the absolute equilibrium
states, to arrive at the spectra for the invariants, and to determine the
direction of the cascades, e.g., generalizations of the well-known ideal MHD
inverse cascade of magnetic helicity. After a similar analysis is conducted for
XMHD by inspecting second order structure functions and absolute equilibrium
states, a couple of interesting results emerge. When cross helicity is taken to
be ignorable, the inverse cascade of injected magnetic helicity also occurs in
the Hall MHD range - this is shown to be consistent with previous results in
the literature. In contrast, in the inertial MHD range, viz. at scales smaller
than the electron skin depth, all spectral quantities are expected to undergo
direct cascading. The consequences and relevance of our results in space and
astrophysical plasmas are also briefly discussed.


title:
Magnetic Chirality Induced from Ruderman-Kittel-Kasuya-Yosida
  Interaction at an Interface of a Ferromagnet/Heavy Metal Heterostructure

abstract:
  We study a microscopic derivation and the properties of the
Dzyaloshinskii-Moriya interaction (DMI) between local magnetic moments in
ferromagnet/heavy metal heterostructures. First, we derive DMI by
Ruderman-Kittel-Kasuya-Yosida interaction through electrons in a heavy metal
with Rashba spin orbit interaction (SOI). Next, we study the dependences of the
DMI on the Rashba SOI, lattice constant, and chemical potential. We find that
the DMI amplitude increases linearly when the Rashba SOI is small, has a
maximum when the Rashba SOI is comparable to the hopping integral, and
decreases when the Rashba SOI is large. The sign of the DMI not only changes
depending on the sign of the Rashba SOI but also the lattice constants and the
chemical potential of the heavy metal. The implications of the obtained results
for experiments are discussed.


title: Trace Formulas for a Class of non-Fredholm Operators: A Review

abstract:
  We review previous work on spectral flow in connection with certain
self-adjoint model operators $\{A(t)\}_{t\in \mathbb{R}}$ on a Hilbert space
$\mathcal{H}$, joining endpoints $A_\pm$, and the index of the operator
$D_{A}^{}= (d/d t) + A$ acting in $L^2(\mathbb{R}; \mathcal{H})$, where $A$
denotes the operator of multiplication $(A f)(t) = A(t)f(t)$. In this article
we review what is known when these operators have some essential spectrum and
describe some new results in terms of associated spectral shift functions.
  We are especially interested in extensions to non-Fredholm situations,
replacing the Fredholm index by the Witten index, and use a particular
$(1+1)$-dimensional model setup to illustrate our approach based on spectral
shift functions.


title: Knowing the Model

abstract:
  Epistemic modal logic normally views an epistemic situation as a Kripke
model. We consider a more basic approach: to view an epistemic situation as a
set W of possible states/worlds -- maximal consistent sets of propositions --
with conventional accessibility relations determined by W. We find that in many
epistemic situations, W is not a Kripke model: a necessary and sufficient
condition for W to be a Kripke model is the so-called `fully explanatory
property' - a propositional form of common knowledge of the model - which has
been a hidden (and overlooked) assumption in epistemic modal logic. We sketch a
theory that describes epistemic models in their generality. We argue for
conceptual and practical value of new models, specifically for representing
partial knowledge, asymmetric knowledge, and awareness.


title:
Solar system tests for realistic $f(T)$ models with nonminimal
  torsion-matter coupling

abstract:
  In the previous paper, we have constructed two $f(T)$ models with nonminimal
torsion-matter coupling extension, which are successful in describing the
evolution history of the Universe including the radiation-dominated era, the
matter-dominated era, and the present accelerating expansion. Meantime, the
significant advantage of these models is that they could avoid the cosmological
constant problem of $\Lambda$CDM. However, the nonminimal coupling between
matter and torsion will affect the tests of Solar system. In this paper, we
study the effects of Solar system in these models, including the gravitation
redshift, geodetic effect and perihelion preccesion. We find that Model I can
pass all three of the Solar system tests. For Model II, the parameter is
constrained by the measure of the perihelion precession of Mercury.


title: What is the Best Way for Extracting Meaningful Attributes from Pictures?

abstract:
  Automatic attribute discovery methods have gained in popularity to extract
sets of visual attributes from images or videos for various tasks. Despite
their good performance in some classification tasks, it is difficult to
evaluate whether the attributes discovered by these methods are meaningful and
which methods are the most appropriate to discover attributes for visual
descriptions. In its simplest form, such an evaluation can be performed by
manually verifying whether there is any consistent identifiable visual concept
distinguishing between positive and negative exemplars labelled by an
attribute. This manual checking is tedious, expensive and labour intensive. In
addition, comparisons between different methods could also be problematic as it
is not clear how one could quantitatively decide which attribute is more
meaningful than the others. In this paper, we propose a novel attribute
meaningfulness metric to address this challenging problem. With this metric,
automatic quantitative evaluation can be performed on the attribute sets; thus,
reducing the enormous effort to perform manual evaluation. The proposed metric
is applied to some recent automatic attribute discovery and hashing methods on
four attribute-labelled datasets. To further validate the efficacy of the
proposed method, we conducted a user study. In addition, we also compared our
metric with a semi-supervised attribute discover method using the mixture of
probabilistic PCA. In our evaluation, we gleaned several insights that could be
beneficial in developing new automatic attribute discovery methods.


title:
Fermi Surface of Metallic V$_2$O$_3$ from Angle-Resolved Photoemission:
  Mid-level Filling of $e_g^{\pi}$ Bands

abstract:
  Using angle resolved photoemission spectroscopy (ARPES) we report the first
band dispersions and distinct features of the bulk Fermi surface (FS) in the
paramagnetic metallic phase of the prototypical metal-insulator transition
material V$_2$O$_3$. Along the $c$-axis we observe both an electron pocket and
a triangular hole-like FS topology, showing that both V 3$d$ $a_{1g}$ and
$e_g^{\pi}$ states contribute to the FS. These results challenge the existing
correlation-enhanced crystal field splitting theoretical explanation for the
transition mechanism and pave the way for the solution of this mystery.


title:
The Health Status of a Population: Health State and Survival Curves, and
  HALE Estimates

abstract:
  In this paper we explore the very important case of finding a health measure
in the lines of the survival curve but independent of the standard deviation
parameter. This is done by estimating the health state curve and calculating
the total area under the curve. An interesting comparison with the survival
curves is done. The health status measure (HSM or HS) resulting is of the form
of the life expectancy (LE) as it is expressed in terms of years of age. The HS
is independent of the standard deviation. When a perfect rectangularization of
the survival curve appear, the LE is equal to the age where the health state
curve approaches zero. The provided HS form gives rise to an interesting
classification of various countries. The results are close to those obtained by
the LE estimator with an interesting reorganization of country ranking. We also
provide illustrations of our estimated Health Status along with comparative
presentations of the Healthy Life Expectancy and the HALE measures in several
countries. Theoretical issues are provided and important stochastic simulations
are done along with reproduction of the death probability density forms.


title: Group SLOPE - adaptive selection of groups of predictors

abstract:
  Sorted L-One Penalized Estimation (SLOPE) is a relatively new convex
optimization procedure which allows for adaptive selection of regressors under
sparse high dimensional designs. Here we extend the idea of SLOPE to deal with
the situation when one aims at selecting whole groups of explanatory variables
instead of single regressors. Such groups can be formed by clustering strongly
correlated predictors or groups of dummy variables corresponding to different
levels of the same qualitative predictor. We formulate the respective convex
optimization problem, gSLOPE (group SLOPE), and propose an efficient algorithm
for its solution. We also define a notion of the group false discovery rate
(gFDR) and provide a choice of the sequence of tuning parameters for gSLOPE so
that gFDR is provably controlled at a prespecified level if the groups of
variables are orthogonal to each other. Moreover, we prove that the resulting
procedure adapts to unknown sparsity and is asymptotically minimax with respect
to the estimation of the proportions of variance of the response variable
explained by regressors from different groups. We also provide a method for the
choice of the regularizing sequence when variables in different groups are not
orthogonal but statistically independent and illustrate its good properties
with computer simulations. Finally, we illustrate the advantages of gSLOPE in
the context of Genome Wide Association Studies. R package grpSLOPE with
implementation of our method is available on CRAN.


title:
AC transport and full-counting statistics of molecular junctions in the
  weak electron-vibration coupling regime

abstract:
  The coupling of the charge carriers passing through a molecule bridging two
bulky conductors with local vibrational modes of the molecule, gives rise to
distinct features in the electronic transport properties on one hand, and to
nonequilibrium features in the vibrations' properties, e.g., their population,
on the other. Here we explore theoretically a generic model for a molecular
junction biased by an arbitrary dc voltage in the weak-coupling regime. We
analyze the signature of the electron-vibration interaction on the
full-counting statistics of the current fluctuations (i.e., the cumulant
generating-function of the current correlations), we give a detailed account of
the response to an ac field exerted on the junction (on top of the dc bias
voltage), we study the nonequilibrium distribution of the vibrational modes and
the fluctuations they cause in the displacement of the molecule center of mass.
The calculations use the technique of nonequilibrium Green's functions, and
treat the electron-vibration coupling in perturbation theory, within the
random-phase approximation when required.


title:
A Rich Source of Labels for Deep Network Models of the Primate Dorsal
  Visual Stream

abstract:
  Deep convolutional neural networks (CNNs) have structures that are loosely
related to that of the primate visual cortex. Surprisingly, when these networks
are trained for object classification, the activity of their early,
intermediate, and later layers becomes closely related to activity patterns in
corresponding parts of the primate ventral visual stream. The activity
statistics are far from identical, but perhaps remaining differences can be
minimized in order to produce artificial networks with highly brain-like
activity and performance, which would provide a rich source of insight into
primate vision. One way to align CNN activity more closely with neural activity
is to add cost functions that directly drive deep layers to approximate neural
recordings. However, suitably large datasets are particularly difficult to
obtain for deep structures, such as the primate middle temporal area (MT). To
work around this barrier, we have developed a rich empirical model of activity
in MT. The model is pixel-computable, so it can provide an arbitrarily large
(but approximate) set of labels to better guide learning in the corresponding
layers of deep networks. Our model approximates a number of MT phenomena more
closely than previous models. Furthermore, our model approximates population
statistics in detail through fourteen parameter distributions that we estimated
from the electrophysiology literature. In general, deep networks with internal
representations that closely approximate those of the brain may help to clarify
the mechanisms that produce these representations, and the roles of various
properties of these representations in performance of vision tasks. Although
our empirical model inevitably differs from real neural activity, it allows
tuning properties to be modulated independently, which may allow very detailed
exploration of the origins and functional roles of these properties.


title:
ProvDB: A System for Lifecycle Management of Collaborative Analysis
  Workflows

abstract:
  As data-driven methods are becoming pervasive in a wide variety of
disciplines, there is an urgent need to develop scalable and sustainable tools
to simplify the process of data science, to make it easier to keep track of the
analyses being performed and datasets being generated, and to enable
introspection of the workflows. In this paper, we describe our vision of a
unified provenance and metadata management system to support lifecycle
management of complex collaborative data science workflows. We argue that a
large amount of information about the analysis processes and data artifacts
can, and should be, captured in a semi-passive manner; and we show that
querying and analyzing this information can not only simplify bookkeeping and
debugging tasks for data analysts but can also enable a rich new set of
capabilities like identifying flaws in the data science process itself. It can
also significantly reduce the time spent in fixing post-deployment problems
through automated analysis and monitoring. We have implemented an initial
prototype of our system, called ProvDB, on top of git (a version control
system) and Neo4j (a graph database), and we describe its key features and
capabilities.


title:
Improvements in Sub-optimal Solving of the $(N^2-1)$-Puzzle via Joint
  Relocation of Pebbles and its Applications to Rule-based Cooperative
  Path-Finding

abstract:
  The problem of solving $(n^2-1)$-puzzle and cooperative path-finding (CPF)
sub-optimally by rule based algorithms is addressed in this manuscript. The
task in the puzzle is to rearrange $n^2-1$ pebbles on the square grid of the
size of n x n using one vacant position to a desired goal configuration. An
improvement to the existent polynomial-time algorithm is proposed and
experimentally analyzed. The improved algorithm is trying to move pebbles in a
more efficient way than the original algorithm by grouping them into so-called
snakes and moving them jointly within the snake. An experimental evaluation
showed that the algorithm using snakes produces solutions that are 8% to 9%
shorter than solutions generated by the original algorithm.
  The snake-based relocation has been also integrated into rule-based
algorithms for solving the CPF problem sub-optimally, which is a closely
related task. The task in CPF is to relocate a group of abstract robots that
move over an undirected graph to given goal vertices. Robots can move to
unoccupied neighboring vertices and at most one robot can be placed in each
vertex. The $(n^2-1)$-puzzle is a special case of CPF where the underlying
graph is represented by a 4-connected grid and there is only one vacant vertex.
Two major rule-based algorithms for CPF were included in our study - BIBOX and
PUSH-and-SWAP (PUSH-and-ROTATE). Improvements gained by using snakes in the
BIBOX algorithm were stable around 30% in $(n^2-1)$-puzzle solving and up to
50% in CPFs over bi-connected graphs with various ear decompositions and
multiple vacant vertices. In the case of the PUSH-and-SWAP algorithm the
improvement achieved by snakes was around 5% to 8%. However, the improvement
was unstable and hardly predictable in the case of PUSH-and-SWAP.


title:
Improving Short Utterance PLDA Speaker Verification using SUV Modelling
  and Utterance Partitioning Approach

abstract:
  This paper analyses the short utterance probabilistic linear discriminant
analysis (PLDA) speaker verification with utterance partitioning and short
utterance variance (SUV) modelling approaches. Experimental studies have found
that instead of using single long-utterance as enrolment data, if long enrolled
utterance is partitioned into multiple short utterances and average of short
utterance i-vectors is used as enrolled data, that improves the Gaussian PLDA
(GPLDA) speaker verification. This is because short utterance i-vectors have
speaker, session and utterance variations, and utterance-partitioning approach
compensates the utterance variation. Subsequently, SUV-PLDA is also studied
with utterance partitioning approach, and utterance partitioning-based
SUV-GPLDA system shows relative improvement of 9% and 16% in EER for NIST 2008
and NIST 2010 truncated 10sec-10sec evaluation condition as utterance
partitioning approach compensates the utterance variation and SUV modelling
approach compensates the mismatch between full-length development data and
short-length evaluation data.


title:
Creation and Measurement of Broadband Squeezed Vacuum from a Ring
  Optical Parametric Oscillator

abstract:
  We report a 65MHz-bandwidth triangular-shaped optical parametric oscillator
(OPO) for squeezed vacuum generation at 860nm. The triangle structure of our
OPO enables the round-trip length to reach 45mm as a ring cavity, which
provides a counter circulating optical path available for introducing a probe
beam or generating another squeezed vacuum. Hence our OPO is suitable for the
applications in high-speed quantum information processing where two or more
squeezed vacua form a complicated interferometer, like continuous-variable
quantum teleportation. With a homemade, broadband and low-loss homodyne
detector, a direct measurement shows 8.4dB of squeezing at 3MHz and also 2.4dB
of squeezing at 100MHz.


title:
Identification of Intended Arm Movement Using Electrocorticographic
  Signals

abstract:
  A Brain Computer Interface (BCI) is a communication system that receives
neurological signals from the brain and translates them into control commands
for electrical (e.g., computer mouse) and electromechanical (e.g., Wheelchair)
devices. The development of such systems was intended originally to aid
individuals with a condition called locked-in syndrome. Individuals with this
condition have lost all their voluntary muscle control but remain cognitively
intact (i.e., mentally aware of their surroundings- can feel emotions,
recognize objects/people but are unable to move). This means that they are
trapped in their own bodies. The use of BCI may one day improve the
independence and quality of life of people with this disability.


title: On Convergence of Oscillatory Ergodic Hilbert Transforms

abstract:
  We introduce sufficient conditions on discrete singular integral operators
for their maximal truncations to satisfy a sparse bound. The latter imply a
range of quantitative weighted inequalities, which are new. As an application,
we prove the following ergodic theorem: let $p(t)$ be a Hardy field function
which grows "super-linearly" and stays "sufficiently far" from polynomials. We
show that for each measure-preserving system, $(X,\Sigma,\mu,\tau)$, with
$\tau$ a measure-preserving $\mathbb{Z}$-action, the modulated one-sided
ergodic Hilbert transform \[ \sum_{n=1}^\infty \frac{e^{2\pi i p(n)}}{n} \tau^n
f(x) \] converges $\mu$-a.e. for each $f \in L^r(X), \ 1 \leq r < \infty$. This
affirmatively answers a question of J. Rosenblatt.
  In the second part of the paper, we establish almost sure sparse bounds for
random one-sided ergodic Hilbert transforms, \[ \sum_{n=1}^\infty \frac{X_n}{n}
\tau^n f(x), \] where $\{ X_n \}$ are uniformly bounded, independent, and
mean-zero random variables.


title: Local arboreal representations

abstract:
  Let $K$ be a field complete with respect to a discrete valuation $v$ of
residue characteristic $p$. Let $f(z) \in K[z]$ be a separable polynomial of
the form $z^\ell-c.$ Given $a \in K$, we examine the Galois groups and
ramification groups of the extensions of $K$ generated by the solutions to
$f^n(z)=a$. The behavior depends upon $v(c)$, and we find that it shifts
dramatically as $v(c)$ crosses a certain value: $0$ in the case $p \nmid \ell$,
and $-p/(p-1)$ in the case $p=\ell$.


title:
Anomalous Hall effect of ferromagnetic Fe3Sn2 single crystal with
  geometrically frustrated kagome lattice

abstract:
  The anomalous Hall effect is investigated for ferromagnetic Fe3Sn2 single
crystal with geometrically frustrated kagome bilayer of Fe. The scaling
behavior between anomalous Hall resistivity rho_{xy}^{A} and longitudinal
resistivity rho_{xx} is quadratic and further analysis implies that the AHE in
Fe3Sn2 single crystal should be dominated by the intrinsic Karplus-Luttinger
mechanism rather than extrinsic skew-scattering or side-jump mechanisms.
Moreover, there is a sudden jump of anomalous Hall conductivity sigma_{xy}^{A}
appearing at about 100 K where the spin-reorientation transition from the c
axis to the ab plane is completed. This change of sigma_{xy}^{A} might be
related to the evolution of Fermi surface induced by the spin-reorientation
transition.


title: Designing compensated magnetic states in tetragonal Mn3Ge-based alloys

abstract:
  Magnetic compensated state attracted much interests due to the observed large
exchange bias and large coercivity, and its potential applications in the
antiferromagnetic spintronics with merit of no stray field. In this work, by ab
initio calculations with KKR-CPA for the treatment of random substitution, we
obtain the complete compensated states in the Ni (Pd, Pt) doped Mn3Ge-based
D022-type tetragonal Heusler alloys. We find the total moment change is
asymmetric across the compensation point (at ~ x = 0.3) in Mn3-xYxGe (Y = Ni,
Pd, Pt), which is highly conforming to that experimentally observed in Mn3Ga.
In addition, an uncommon discontinuous jump is observed across the critical
zero-moment point, indicating that some non-trivial properties can emerge at
this point. Further electronic analysis for the three compensation compositions
reveals large spin polarizations, together with the high Curie temperature of
the host Mn3Ge, making them promising candidates for spin transfer torque
applications.


title: A Game-Theoretic Analysis of Adversarial Classification

abstract:
  Attack detection is usually approached as a classification problem. However,
standard classification tools often perform poorly because an adaptive attacker
can shape his attacks in response to the algorithm. This has led to the recent
interest in developing methods for adversarial classification, but to the best
of our knowledge, there have been very few prior studies that take into account
the attacker's tradeoff between adapting to the classifier being used against
him with his desire to maintain the efficacy of his attack. Including this
effect is key to derive solutions that perform well in practice.
  In this investigation we model the interaction as a game between a defender
who chooses a classifier to distinguish between attacks and normal behavior
based on a set of observed features and an attacker who chooses his attack
features (class 1 data). Normal behavior (class 0 data) is random and
exogenous. The attacker's objective balances the benefit from attacks and the
cost of being detected while the defender's objective balances the benefit of a
correct attack detection and the cost of false alarm. We provide an efficient
algorithm to compute all Nash equilibria and a compact characterization of the
possible forms of a Nash equilibrium that reveals intuitive messages on how to
perform classification in the presence of an attacker. We also explore
qualitatively and quantitatively the impact of the non-attacker and underlying
parameters on the equilibrium strategies.


title: Multiple Instance Fuzzy Inference Neural Networks

abstract:
  Fuzzy logic is a powerful tool to model knowledge uncertainty, measurements
imprecision, and vagueness. However, there is another type of vagueness that
arises when data have multiple forms of expression that fuzzy logic does not
address quite well. This is the case for multiple instance learning problems
(MIL). In MIL, an object is represented by a collection of instances, called a
bag. A bag is labeled negative if all of its instances are negative, and
positive if at least one of its instances is positive. Positive bags encode
ambiguity since the instances themselves are not labeled. In this paper, we
introduce fuzzy inference systems and neural networks designed to handle bags
of instances as input and capable of learning from ambiguously labeled data.
First, we introduce the Multiple Instance Sugeno style fuzzy inference
(MI-Sugeno) that extends the standard Sugeno style inference to handle
reasoning with multiple instances. Second, we use MI-Sugeno to define and
develop Multiple Instance Adaptive Neuro Fuzzy Inference System (MI-ANFIS). We
expand the architecture of the standard ANFIS to allow reasoning with bags and
derive a learning algorithm using backpropagation to identify the premise and
consequent parameters of the network. The proposed inference system is tested
and validated using synthetic and benchmark datasets suitable for MIL problems.
We also apply the proposed MI-ANFIS to fuse the output of multiple
discrimination algorithms for the purpose of landmine detection using Ground
Penetrating Radar.


title: Joint Relay-User Beamforming Design in Full-Duplex Two-Way Relay Channel

abstract:
  A full-duplex two-way relay channel with multiple antennas is considered. For
this three-node network, the beamforming design needs to suppress
self-interference. While a traditional way is to apply zero-forcing for
self-interference mitigation, it may harm the desired signals. In this paper, a
design which reserves a fraction of self-interference is proposed by solving a
quality-of-service constrained beamforming design problem. Since the problem is
challenging due to the loop self-interference, a convergence-guaranteed
alternating optimization algorithm is proposed to jointly design the relay-user
beamformers. Numerical results show that the proposed scheme outperforms
zero-forcing method, and achieves a transmit power close to the ideal case.


title:
Large-p_T production of D mesons at the LHCb in the parton Reggeization
  approach

abstract:
  The production of D mesons in proton-proton collisions at the LHCb detector
is studied. We consider the single production of D^0, D^+, D^star, and D_s^+
mesons and correlation spectra in the production of DbarD and DD pairs at the
sqrt{S}=7 TeV and sqrt{S}=13 TeV. In case of the single D-meson production we
calculate differential cross sections over transverse momentum p_T while in the
pair DbarD,DD-meson production the cross sections are calculated over the
azimuthal angle difference, rapidity difference, invariant mass of the pair M
and over the p_T of the one meson from a pair. The cross sections are obtained
at the leading order of the parton Reggeization approach using
Kimber-Martin-Ryskin unintegrated parton distribution functions in a proton. To
describe the D-meson production we use universal scale-dependent c-quark and
gluon fragmentation functions fitted to e^+e^- annihilation data from CERN
LEP1. Our predictions find a good agreement with the LHCb Collaboration data
within uncertainties and without free parameters.


title: Biharmonic tori in spheres

abstract:
  We consider proper-biharmonic flat tori with constant mean curvature (CMC) in
spheres and find necessary and sufficient conditions for certain rectangular
tori and square tori to admit full CMC proper-biharmonic immersions in
$\mathbb{S}^n$, as well as the explicit expressions of some of these
immersions.


title:
The sixth moment of the Riemann zeta function and ternary additive
  divisor sums

abstract:
  Hardy and Littlewood initiated the study of the $2k$-th moments of the
Riemann zeta function on the critical line. In 1918 Hardy and Littlewood
established an asymptotic formula for the second moment and in 1926 Ingham
established an asymptotic formula for the fourth moment. Since then no other
moments have been asymptotically evaluated. In this article we study the sixth
moment of the zeta function on the critical line. We show that a conjectural
formula for a certain family of ternary additive divisor sums implies an
asymptotic formula with power savings error term for the sixth moment of the
Riemann zeta function on the critical line. This provides a rigorous proof for
a heuristic argument of Conrey and Gonek. Furthermore, this gives some evidence
towards a conjecture of Conrey, Keating, Farmer, Rubinstein, and Snaith on
shifted moments of the Riemann zeta function. In addition, this improves on a
theorem of Ivic, who obtained an upper bound for the the sixth moment of the
zeta function, based on the assumption of a conjectural formula for correlation
sums of the triple divisor function.


title:
Short-term H{\alpha} line variations in Classical Be stars: 59 Cyg and
  OT Gem

abstract:
  We present the optical spectroscopic study of two Classical Be stars, 59 Cyg
and OT Gem obtained over a period of few months in 2009. We detected a rare
triple-peak H$\alpha$ emission phase in 59 Cyg and a rapid decrease in the
emission strength of H$\alpha$ in OT Gem, which are used to understand their
circumstellar disks. We find that 59 Cyg is likely to be rapid rotator,
rotating at a fractional critical rotation of $\sim$ 0.80. The radius of the
H$\alpha$ emission region for 59 Cyg is estimated to be $R_d/R_*$ $\sim$ 10.0,
assuming a Keplerian disk, suggesting that it has a large disk. We classify
stars which have shown triple-peaks into two groups and find that the
triple-peak emission in 59 Cyg is similar to $\zeta$ Tau. OT Gem is found to
have a fractional critical rotation of $\sim$ 0.30, suggesting that it is
either a slow rotator or viewed in low inclination. In OT Gem, we observed a
large reduction in the radius of the H$\alpha$ emission region from $\sim$ 6.9
to $\sim$ 1.7 in a period of three months, along with the reduction in the
emission strength. Our observations suggest that the disk is lost from outside
to inside during this disk loss phase in OT Gem.