title: The HCN-Water Ratio in the Planet Formation Region of Disks

abstract:
  We find a trend between the mid-infrared HCN/H2O flux ratio and submillimeter
disk mass among T Tauri stars in Taurus. While it may seem puzzling that the
molecular emission properties of the inner disk (< few AU) are related to the
properties of the outer disk (beyond ~20 AU) probed by the submillimeter
continuum, an interesting possible interpretation is that the trend is a result
of planetesimal and protoplanet formation. Because objects this large are
decoupled from the accretion flow, when they form, they can lock up water (and
oxygen) beyond the snow line, thereby enhancing the C/O ratio in the inner disk
and altering the molecular abundances there. We discuss the assumptions that
underlie this interpretation, a possible alternative explanation, and related
open questions that motivate future work. Whatever its origin, understanding
the meaning of the relation between the HCN/H2O ratio and disk mass is of
interest as trends like this among T Tauri disk properties are relatively rare.


title:
Dyson-Schwinger approach to color superconductivity at finite
  temperature and density

abstract:
  We investigate the phases of dense QCD matter at finite temperature with
Dyson-Schwinger equations for the quark propagator for N_f=2+1 flavors. For the
gluon propagator we take a fit to quenched lattice data and add quark-loop
effects perturbatively in a hard-thermal-loop--hard-dense-loop approximation.
We consider 2SC and CFL-like pairing with chiral up and down quarks and massive
strange quarks and present results for the condensates and the phase diagram.
We find a dominant CFL phase at chemical potentials larger than 500-600 MeV. At
lower values of the chemical potential we find a 2SC phase, which also exists
in a small band at higher temperatures for larger chemical potentials. With
values of 20-30 MeV, the critical temperatures to the normal phase turn out to
be quite small.


title:
Measurement of Two Low-Temperature Energy Gaps in the Electronic
  Structure of Antiferromagnetic USb2 Using Ultrafast Optical Spectroscopy

abstract:
  Ultrafast optical spectroscopy is used to study the antiferromagnetic
f-electron system USb2. We observe the opening of two charge gaps at low
temperatures (<45 K), arising from renormalization of the electronic structure.
Analysis of our data indicates that one gap is due to hybridization between
localized f-electron and conduction electron bands, while band renormalization
involving magnons leads to the emergence of the second gap. These experiments
thus enable us to shed light on the complex electronic structure emerging at
the Fermi surface in f-electron systems.


title:
Crystals, magnetic and electronic properties of a new ThCr2Si2-type
  BaMn2Bi2 and K-doped compositions

abstract:
  This is a report on the new 122 ternary transition-metal pnictide of
BaMn2Bi2, which is crystallized from bismuth flux. BaMn2Bi2 adopts
ThCr2Si2-type structure (I4/mmm) with a = 4.4902(3) {\AA} and c = 14.687(1)
{\AA}; it is antiferromagnetic with anisotropic magnetic susceptibility and
semiconducting with a band gap of Eg = 6 meV. Heat capacity result confirms the
insulating ground state in BaMn2Bi2 with the electronic residual Sommerfeld
coefficient of {\gamma} ~ 0. The high temperature magnetization results show
that magnetic ordering temperature is TN ~ 400 K. Hole-doping in BaMn2Bi2 via
potassium in Ba1-xKxMn2Bi2 results in metallic behavior for x = 0.10(1),
0.32(1) and 0.36(1). With K-doping, more magnetically anisotropic behavior is
observed. Although there is a downturn in electrical resistivity and low-field
magnetization data below 4 K in > 30%-doped crystals, there is no sign of zero
resistance or diamagnetism. This manuscript is a report on new materials of
BaMn2Bi2 and Ba1-xKxMn2Bi2 (0 < x < 0.4). Results from powder X-ray
diffraction, anisotropic temperature- and field-dependent magnetization,
temperature-and field-dependent electrical resistivity, and heat capacity are
presented.


title:
Single molecule simulations in complex geometries with embedded dynamic
  one-dimensional structures

abstract:
  Stochastic models of reaction-diffusion systems are important for the study
of biochemical reaction networks where species are present in low copy numbers
or if reactions are highly diffusion limited. In living cells many such systems
include reactions and transport on one-dimensional structures, such as DNA and
microtubules. The cytoskeleton is a dynamic structure where individual fibers
move, grow and shrink. In this paper we present a simulation algorithm that
combines single molecule simulations in three-dimensional space with single
molecule simulations on one-dimensional structures of arbitrary shape.
Molecules diffuse and react with each other in space, they associate to and
dissociate from one-dimensional structures as well as diffuse and react with
each other on the one-dimensional structure. A general curve embedded in space
can be approximated by a piecewise linear curve to arbitrary accuracy. The
resulting algorithm is hence very flexible. Molecules bound to a curve can move
by pure diffusion or via active transport, and the curve can move in space as
well as grow and shrink. The flexibility and accuracy of the algorithm is
demonstrated in four numerical examples.


title: Short GRBs and dark matter seeding in neutron stars

abstract:
  We present a mechanism based on internal self-annihilation of dark matter
accreted from the galactic halo in the inner regions of neutron stars that may
trigger the full or partial conversion into a quark star. We explain how this
effect may induce a gamma ray burst that could be classified as short,
according to the usual definition based on time duration of the prompt
gamma-ray emission. This mechanism differs in many aspects from the most
discussed scenario associating short gamma-ray bursts with compact object
binary mergers. We list possible observational signatures that should help to
distinguish between these two possible classes of progenitors.


title: Efficient particle filtering through residual nudging

abstract:
  We introduce an auxiliary technique, called residual nudging, to the particle
filter to enhance its performance in cases that it performs poorly. The main
idea of residual nudging is to monitor, and if necessary, adjust the residual
norm of a state estimate in the observation space so that it does not exceed a
pre-specified threshold. We suggest a rule to choose the pre-specified
threshold, and construct a state estimate accordingly to achieve this
objective. Numerical experiments suggest that introducing residual nudging to a
particle filter may (substantially) improve its performance, in terms of filter
accuracy and/or stability against divergence, especially when the particle
filter is implemented with a relatively small number of particles.

categories: physics.ao-ph math.ST physics.data-an stat.TH


title:
Search for pair-production of strongly-interacting particles decaying to
  pairs of jets in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

abstract:
  We present a search for the pair-production of a non-standard-model
strongly-interacting particle that decays to a pair of quarks or gluons,
leading to a final state with four hadronic jets. We consider both non-resonant
production via an intermediate gluon as well as resonant production via a
distinct non-standard-model intermediate strongly-interacting particle. We use
data collected by the CDF experiment in proton-antiproton collisions at
$\sqrt{s}=1.96$ TeV corresponding to an integrated luminosity of 6.6 fb$^{-1}$.
We find the data to be consistent with standard model predictions. We report
limits on $\sigma(p\bar{p}\rightarrow$ {\it jjjj}$)$ as a function of the
masses of the hypothetical intermediate particles. Upper limits on the
production cross sections for non-standard-model particles in several resonant
and non-resonant processes are also derived.


title: Random graphs of free groups contain surface subgroups

abstract: A random graph of free groups contains a surface subgroup


title: Curvatures of direct image sheaves of vector bundles and applications I

abstract:
  Let $p:\sXS$ be a proper K\"ahler fibration and $\sE\sX$ a Hermitian
holomorphic vector bundle.
  As motivated by the work of Berndtsson(\cite{Berndtsson09a}), by using basic
Hodge theory, we derive several general curvature formulas for the direct image
$p_*(K_{\sX/S}\ts \sE)$ for general Hermitian holomorphic vector bundle $\sE$
in a simple way.
  A straightforward application is that, if the family $\sXS$ is
infinitesimally trivial and Hermitian vector bundle $\sE$ is Nakano-negative
along the base $S$, then the direct image $p_*(K_{\sX/S}\ts \sE)$ is
Nakano-negative. We also use these curvature formulas to study the moduli space
of projectively flat vector bundles with positive first Chern classes and
obtain that, if the Chern curvature of direct image $p_*(K_{X}\ts E)$--of a
positive projectively flat family $(E,h(t))_{t\in \mathbb D}X$--vanishes, then
the curvature forms of this family are connected by holomorphic automorphisms
of the pair $(X,E)$.


title:
The Role of Superluminal Electromagnetic Waves in Pulsar Wind
  Termination Shocks

abstract:
  The dynamics of a standing shock front in a Poynting-flux dominated
relativistic flow is investigated by using a one-dimensional, relativistic,
two-fluid simulation. An upstream flow containing a circularly polarized,
sinusoidal magnetic shear wave is considered, mimicking a wave driven by an
obliquely rotating pulsar. It is demonstrated that this wave is converted into
large amplitude electromagnetic waves with superluminal phase speeds by
interacting with the shock when the shock-frame frequency of the wave exceeds
the proper plasma frequency. The superluminal waves propagate in the upstream,
modify the shock structure substantially, and form a well-developed precursor
region ahead of a subshock. Dissipation of Poynting flux occurs in the
precursor as well as in the downstream region through a parametric instability
driven by the superluminal waves. The Poynting flux remaining in the downstream
region is carried entirely by the superluminal waves. The downstream plasma is
therefore an essentially unmagnetized, relativistically hot plasma with a
non-relativistic flow speed, as suggested by observations of pulsar wind
nebulae.


title: Multi-element Doppler imaging of the CP2 star HD 3980

abstract:
  In atmospheres of magnetic main-sequence stars, the diffusion of chemical
elements leads to a number of observed anomalies, such as abundance spots
across the stellar surface. The aim of this study was to derive a detailed
picture of the surface abundance distribution of the magnetic chemically
peculiar star HD 3980. Based on high-resolution, phase-resolved spectroscopic
observations of the magnetic A-type star HD 3980, the inhomogeneous surface
distribution of 13 chemical elements (Li, O, Si, Ca, Cr, Mn, Fe, La, Ce, Pr,
Nd, Eu, and Gd) has been reconstructed. The INVERS12 code was used to invert
the rotational variability in line profiles to elemental surface distributions.
Assuming a centered, dominantly dipolar magnetic field configuration, we find
that Li, O, Mg, Pr, and Nd are mainly concentrated in the area of the magnetic
poles and depleted in the regions around the magnetic equator. The high
abundance spots of Si, La, Ce, Eu, and Gd are located between the magnetic
poles and the magnetic equator. Except for La, which is clearly depleted in the
area of the magnetic poles, no obvious correlation with the magnetic field has
been found for these elements otherwise. Ca, Cr, and Fe appear enhanced along
the rotational equator and the area around the magnetic poles. The intersection
between the magnetic and the rotational equator constitutes an exception,
especially for Ca and Cr, which are depleted in that region. No obvious
correlation between the theoretically predicted abundance patterns and those
determined in this study could be found. This can be attributed to a lack of
up-to-date theoretical models, especially for rare earth elements.


title:
Fast cooling synchrotron radiation in a decaying magnetic field and
  $\gamma$-ray burst emission mechanism

abstract:
  Synchrotron radiation of relativistic electrons is an important radiation
mechanism in many astrophysical sources. In the sources where the synchrotron
cooling time scale $t_c$ is shorter than the dynamical time scale $t_{dyn}$,
electrons are cooled down below the minimum injection energy. It has been
believed that such "fast cooling" electrons have an energy distribution $dN_e
/d\gamma_e \propto \gamma_e^{-2}$, and their synchrotron radiation flux density
has a spectral shape $F_\nu \propto \nu^{-1/2}$. On the other hand, in a
transient expanding astrophysical source, such as a gamma-ray burst (GRB), the
magnetic field strength in the emission region continuously decreases with
radius. Here we study such a system, and find that in a certain parameter
regime, the fast cooling electrons can have a harder energy spectrum, and the
standard $d N_e / d \gamma_e \propto \gamma_e^{-2}$ spectrum is achieved only
in the deep fast cooling regime when $t_c \ll t_{dyn}$. We apply this new
physical regime to GRBs, and suggest that the GRB prompt emission spectra whose
low-energy photon index $\alpha$ has a typical value -1 could be due to
synchrotron radiation in this moderately fast cooling regime.


title: Random Iteration of Rational Functions

abstract:
  It is a theorem of Denker and Urba\'nski ('91) that if $T:\mathbb C\to\mathbb
C$ is a rational map of degree at least two and if $\phi:\mathbb C\to\mathbb R$
is H\"older continuous and satisfies the "thermodynamic expanding" condition
$P(T,\phi) > \sup(\phi)$, then there exists exactly one equilibrium state $\mu$
for $T$ and $\phi$, and furthermore $(\mathbb C,T,\mu)$ is metrically exact. We
extend these results to the case of a holomorphic random dynamical system on
$\mathbb C$, using the concepts of relative pressure and relative entropy of
such a system, and the variational principle of Bogensch\"utz ('92/'93).
Specifically, if $(T,\Omega,\textbf P,\theta)$ is a holomorphic random
dynamical system on $\mathbb C$ and $\phi:\Omega\to H_\alpha(\mathbb C)$ is a
H\"older continuous random potential function satisfying one of several sets of
technical but reasonable hypotheses, then there exists a unique equilibrium
state of $(\mathbb X,\mathbb T,\phi)$ over $(\Omega,\textbf P,\theta)$.
  Also included is a general (non-thermodynamic) discussion of random dynamical
systems acting on $\mathbb C$, generalizing several basic results from the
deterministic case.


title: On the gravitational self-energy of a spherical shell

abstract:
  According to Einstein's mass-energy equivalence, a body with a given mass
extending in a large region of space, will get a smaller mass when confined
into a smaller region, because of its own gravitational energy. The classical
self-energy problem has been studied in the past in connection with the
renormalization of a charged point particle. Still exact consistent solutions
have not been thoroughly discussed in the simpler framework of Newtonian
gravity. Here we exploit a spherical symmetrical shell model and find two
possible solutions, depending on some additional assumption. The first solution
goes back to Arnowitt, Deser and Misner (1960). The second is new and yields a
new vanishingly small value (10^-55 cm) for the classical electron radius.


title: Subgroup Majorization

abstract:
  The extension of majorization (also called the rearrangement ordering), to
more general groups than the symmetric (permutation) group, is referred to as
$G$-majorization. There are strong results in the case that $G$ is a reflection
group and this paper builds on this theory in the direction of subgroups,
normal subgroups, quotient groups and extensions. The implications for
fundamental cones and order-preserving functions are studied. The main example
considered is the hyperoctahedral group, which, acting on a vector in $\mathbb
R^n$, permutes and changes the signs of components.


title:
Quasars Probing Quasars IV: Joint Constraints on the Circumgalactic
  Medium from Absorption and Emission

abstract:
  We have constructed a sample of 29 close projected quasar pairs where the
background quasar spectrum reveals absorption from optically thick HI gas
associated with the foreground quasar. These unique sightlines allow us to
study the quasar circumgalactic medium (CGM) in absorption and emission
simultaneously, because the background quasar pinpoints large concentrations of
gas where Ly-a emission, resulting from quasar-powered fluorescence, resonant
Ly-a scattering, and/or cooling radiation, is expected. A sensitive
slit-spectroscopic search (1-sigma limits of SB_Lya ~= 3e-18
erg/s/cm^2/arcsec^2) for diffuse Ly-a emission in the environments of the
foreground quasars is conducted. We fail to detect large-scale ~ 100 kpc Ly-a
emission, either at the location of the optically thick absorbers or in the
foreground quasar halos, in all cases except a single system. We interpret
these non-detections as evidence that the gas detected in absorption is
shadowed from the quasar UV radiation due to obscuration effects, which are
frequently invoked in unified models of AGN. Small-scale R_perp <~ 50 kpc
extended Ly-a nebulosities are detected in 34% of our sample, which are likely
the high-redshift analogs of the extended emission-line regions commonly
observed around low-redshift (z < 0.5) quasars. We also detect a compact high
rest-frame equivalent width (W_Lya > 50 A) Ly-alpha-emitter with luminosity
L_Lya =2.1+-0.32e41 erg/s at small impact parameter R_perp=134 kpc from one
foreground quasar, and argue that it is more likely to result from
quasar-powered fluorescence, than simply be a star-forming galaxy clustered
around the quasar. Our observations imply that much deeper integrations with
upcoming integral-field spectrometers such as MUSE and KCWI will be able to
routinely detect a diffuse Ly-a glow around bright quasars on scales R ~ 100
kpc and thus directly image the CGM. [abridged]


title: Resilient Continuous-Time Consensus in Fractional Robust Networks

abstract:
  In this paper, we study the continuous-time consensus problem in the presence
of adversaries. The networked multi-agent system is modeled as a switched
system, where the normal agents have integrator dynamics and the switching
signal determines the topology of the network. We consider several models of
omniscient adversaries under the assumption that at most a fraction of any
normal agent's neighbors may be adversaries. Under this fractional assumption
on the interaction between normal and adversary agents, we show that a novel
graph theoretic metric, called fractional robustness, is useful for analyzing
the network topologies under which the normal agents achieve consensus.


title:
Apparent increase in the thickness of superconducting particles at low
  temperatures measured by electron holography

abstract:
  We predict that superconducting particles will show an apparent increase in
thickness at low temperatures when measured by electron holography. This will
result not from a real thickness increase, rather from an increase in the mean
inner potential sensed by the electron wave traveling through the particle,
originating in expansion of the electronic wavefunction and resulting negative
charge expulsion from the interior to the surface of the superconductor, giving
rise to an increase in the phase shift of the electron wavefront going through
the sample relative to the wavefront going through vacuum. The temperature
dependence of the observed phase shifts will yield valuable new information on
the physics of the superconducting state of metals.


title: On the Galactic Nova Progenitor Population

abstract:
  Of the 350 or more known Galactic classical novae, only a handful of them,
the recurrent novae, have been observed in outburst more than once. At least
eight of these recurrents are known to harbour evolved secondary stars, rather
than the main sequence secondaries typical in classical novae. Here we present
a selection of the work and rationale that led to the proposal of a new nova
classification scheme based not on the outburst properties but on the nature of
the quiescent system. Also outlined are the results of a photometric survey of
a sample of quiescent Galactic novae, showing that the evolutionary state of
the secondary can be easily determined and leading to a number of predictions.
We discuss the implications of these results, including their relevance to
extragalactic work and the proposed link to type Ia supernovae. We also present
a summary of the work using the SMEI instrument to produce exquisite nova
light-curves and confirmation of the pre-maximum halt.


title:
Interplay between quantum confinement and dielectric mismatch for
  ultra-shallow dopants

abstract:
  Understanding the electronic properties of dopants near an interface is a
critical challenge for nano-scale devices. We have determined the effect of
dielectric mismatch and quantum confinement on the ionization energy of
individual acceptors beneath a hydrogen passivated silicon (100) surface.
Whilst dielectric mismatch between the vacuum and the silicon at the interface
results in an image charge which enhances the binding energy of sub-surface
acceptors, quantum confinement is shown to reduce the binding energy. Using
scanning tunneling spectroscopy we measure resonant transport through the
localized states of individual acceptors. Thermal broadening of the conductance
peaks provides a direct measure for the absolute energy scale. Our data
unambiguously demonstrates that these two independent effects compete with the
result that the ionization energy is less than 5 meV lower than the bulk value
for acceptors less than a Bohr radius from the interface.


title:
Local exact controllability of a 1D Bose-Einstein condensate in a
  time-varying box

abstract:
  We consider a one-dimensional Bose-Einstein condensate in a infinite
square-well (box) potential. This is a nonlinear control system in which the
state is the wave function of the Bose Einstein condensate and the control is
the length of the box. We prove that local exact controllability around the
ground state (associated with a fixed length of the box) holds generically with
respect to the chemical potential \mu; i.e. up to an at most countable set of
\mu-values. The proof relies on the linearization principle and the inverse
mapping theorem, as well as ideas from analytic perturbation theory.


title: Conditions for successful data assimilation

abstract:
  We show, using idealized models, that numerical data assimilation can be
successful only if an effective dimension of the problem is not excessive. This
effective dimension depends on the noise in the model and the data, and in
physically reasonable problems it can be moderate even when the number of
variables is huge. We then analyze several data assimilation algorithms,
including particle filters and variational methods. We show that well-designed
particle filters can solve most of those data assimilation problems that can be
solved in principle, and compare the conditions under which variational methods
can succeed to the conditions required of particle filters. We also discuss the
limitations of our analysis.


title:
On the regularity of the free boundary in the optimal partial transport
  problem

abstract:
  This paper concerns the regularity and geometry of the free boundary in the
optimal partial transport problem for general cost functions. More
specifically, we prove that a $C^1$ cost implies a locally Lipschitz free
boundary. As an application, we address a problem discussed by Caffarelli and
McCann \cite{CM} regarding cost functions satisfying the Ma-Trudinger-Wang
condition (A3): if the non-negative source density is in some
$L^p(\mathbb{R}^n)$ space for $p \in (\frac{n+1}{2},\infty]$ and the positive
target density is bounded away from zero, then the free boundary is a
semiconvex $C_{loc}^{1,\alpha}$ hypersurface. Furthermore, we show that a
locally Lipschitz cost implies a rectifiable free boundary and initiate a
corresponding regularity theory in the Riemannian setting.


title:
Quantum phase transitions of three-level atoms interacting with a
  one-mode electromagnetic field

abstract:
  We apply the energy surface method to study a system of Na three-level atoms
interacting with a one-mode radiation field in the \Xi, \Lambda and V
configurations. We obtain an estimation of the ground-state energy, the
expectation value of the total number of excitations, and the separatrix of the
model in the interaction parameter space, and compare the results with the
exact solutions. We have first and second-order phase transitions, except for
the V configuration which only presents second-order phase-transitions.


title: Interplay between localization and absorption in disordered waveguides

abstract:
  This work presents results of ab-initio simulations of continuous wave
transport in disordered absorbing waveguides. Wave interference effects cause
deviations from diffusive picture of wave transport and make the diffusion
coefficient position- and absorption-dependent. As a consequence, the true
limit of a zero diffusion coefficient is never reached in an absorbing random
medium of infinite size, instead, the diffusion coefficient saturates at some
finite constant value. Transition to this absorption-limited diffusion exhibits
a universality which can be captured within the framework of the
self-consistent theory (SCT) of localization. The results of this work (i)
justify use of SCT in analyses of experiments in localized regime, provided
that absorption is not weak; (ii) open the possibility of diffusive description
of wave transport in the saturation regime even when localization effects are
strong.


title: Excitation of coherent phonons in the one-dimensional Bi(114) surface

abstract:
  We present time-resolved photoemission experiments from a peculiar bismuth
surface, Bi(114). The strong one-dimensional character of this surface is
reflected in the Fermi surface, which consists of spin-polarized straight
lines. Our results show that the depletion of the surface state and the
population of the bulk conduction band after the initial optical excitation
persist for very long times. The disequilibrium within the hot electron gas
along with strong electron-phonon coupling cause a displacive excitation of
coherent phonons, which in turn are reflected in coherent modulations of the
electronic states. Beside the well-known A1g bulk phonon mode at 2.76 THz the
time-resolved photoelectron spectra reveal a second mode at 0.72 THz which can
be attributed to an optical surface phonon mode along the atomic rows of the
Bi(114) surface.


title: Another Survey of Foundational Attitudes Towards Quantum Mechanics

abstract:
  Although it has been almost 100 years since the beginnings of quantum
mechanics, the discussions about its interpretation still do not cease.
Therefore, a survey of opinions regarding this matter is of particular
interest. This poll was conducted following an idea and using the methodology
of Schlosshauer et al. (arXiv:1301.1069 [quant-ph]), but among a slightly
different group. It is supposed to give another snapshot of attitudes towards
the interpretation of quantum mechanics and keep discourse about this topic
alive.


title:
Low-Complexity Constrained Constant Modulus SG-based Beamforming
  Algorithms with Variable Step Size

abstract:
  In this paper, two low-complexity adaptive step size algorithms are
investigated for blind adaptive beamforming. Both of them are used in a
stochastic gradient (SG) algorithm, which employs the constrained constant
modulus (CCM) criterion as the design approach. A brief analysis is given for
illustrating their properties. Simulations are performed to compare the
performances of the novel algorithms with other well-known methods. Results
indicate that the proposed algorithms achieve superior performance, better
convergence behavior and lower computational complexity in both stationary and
non-stationary environments.


title:
Guaranteed Performance Leader-follower Control for Multi-agent Systems
  with Linear IQC-Constrained Coupling

abstract:
  This paper considers the leader-follower control problem for a linear
multi-agent system with undirected topology and linear coupling subject to
integral quadratic constraints (IQCs). A consensus-type control protocol is
proposed based on each agent's states relative its neighbors. In addition a
selected set of agents uses for control their states relative the leader. Using
a coordinate transformation, the consensus analysis of the multi-agent system
is recast as a decentralized robust control problem for an auxiliary
interconnected large scale system. Based on this interconnected large scale
system, sufficient conditions are obtained which guarantee that the system
tracks the leader. These conditions guarantee a suboptimal bound on the system
tracking performance. The effectiveness of the proposed method is demonstrated
using a simulation example.


title:
ALMA Observations of SPT-Discovered, Strongly Lensed, Dusty,
  Star-Forming Galaxies

abstract:
  We present Atacama Large Millimeter/submillimeter Array (ALMA) 860 micrometer
imaging of four high-redshift (z=2.8-5.7) dusty sources that were detected
using the South Pole Telescope (SPT) at 1.4 mm and are not seen in existing
radio to far-infrared catalogs. At 1.5 arcsec resolution, the ALMA data reveal
multiple images of each submillimeter source, separated by 1-3 arcsec,
consistent with strong lensing by intervening galaxies visible in near-IR
imaging of these sources. We describe a gravitational lens modeling procedure
that operates on the measured visibilities and incorporates
self-calibration-like antenna phase corrections as part of the model
optimization, which we use to interpret the source structure. Lens models
indicate that SPT0346-52, located at z=5.7, is one of the most luminous and
intensely star-forming sources in the universe with a lensing corrected FIR
luminosity of 3.7 X 10^13 L_sun and star formation surface density of 4200
M_sun yr^-1 kpc^-2. We find magnification factors of 5 to 22, with lens
Einstein radii of 1.1-2.0 arcsec and Einstein enclosed masses of 1.6-7.2x10^11
M_sun. These observations confirm the lensing origin of these objects, allow us
to measure the their intrinsic sizes and luminosities, and demonstrate the
important role that ALMA will play in the interpretation of lensed
submillimeter sources.


title:
Dusty starburst galaxies in the early Universe as revealed by
  gravitational lensing

abstract:
  In the past decade, our understanding of galaxy evolution has been
revolutionized by the discovery that luminous, dusty, starburst galaxies were
1,000 times more abundant in the early Universe than at present. It has,
however, been difficult to measure the complete redshift 2 distribution of
these objects, especially at the highest redshifts (z > 4). Here we report a
redshift survey at a wavelength of three millimeters, targeting carbon monoxide
line emission from the star-forming molecular gas in the direction of
extraordinarily bright millimetrewave-selected sources. High-resolution imaging
demonstrates that these sources are strongly gravitationally lensed by
foreground galaxies. We detect spectral lines in 23 out of 26 sources and
multiple lines in 12 of those 23 sources, from which we obtain robust,
unambiguous redshifts. At least 10 of the sources are found to lie at z > 4,
indicating that the fraction of dusty starburst galaxies at high redshifts is
greater than previously thought. Models of lens geometries in the sample
indicate that the background objects are ultra-luminous infrared galaxies,
powered by extreme bursts of star formation.


title: Generalized Dyck paths of bounded height

abstract:
  Generalized Dyck paths (or discrete excursions) are one-dimensional paths
that take their steps in a given finite set S, start and end at height 0, and
remain at a non-negative height. Bousquet-M\'elou showed that the generating
function E_k of excursions of height at most k is of the form F_k/F_{k+1},
where the F_k are polynomials satisfying a linear recurrence relation. We give
a combinatorial interpretation of the polynomials F_k and of their recurrence
relation using a transfer matrix method. We then extend our method to enumerate
discrete meanders (or paths that start at 0 and remain at a non-negative
height, but may end anywhere). Finally, we study the particular case where the
set S is symmetric and show that several simplifications occur.


title: Robust blind methods using $\ell_p$ quasi norms

abstract:
  It was shown in a previous work that some blind methods can be made robust to
channel order overmodeling by using the $\ell_1$ or $\ell_p$ quasi-norms.
However, no theoretical argument has been provided to support this statement.
In this work, we study the robustness of subspace blind based methods using
$\ell_1$ or $\ell_p$ quasi-norms. For the $\ell_1$ norm, we provide the
sufficient and necessary condition that the channel should satisfy in order to
ensure its identifiability in the noise-less case. We then study its frequency
of occurrence, and deduce the effect of channel parameters on the robustness of
blind subspace methods using $\ell_1$ norms.


title:
ALMA redshifts of millimeter-selected galaxies from the SPT survey: The
  redshift distribution of dusty star-forming galaxies

abstract:
  Using the Atacama Large Millimeter/submillimeter Array (ALMA), we have
conducted a blind redshift survey in the 3 mm atmospheric transmission window
for 26 strongly lensd dusty star-forming galaxies (DSFGs) selected with the
South Pole Telescope (SPT). The sources were selected to have S_1.4mm>20 mJy
and a dust-like spectrum and, to remove low-z sources, not have bright radio
(S_843MHz<6mJy) or far-infrared counterparts (S_100um<1 Jy, S_60um<200mJy). We
robustly detect 44 line features in our survey, which we identify as redshifted
emission lines of 12CO, 13CO, [CI], H2O, and H2O+. We find one or more spectral
features in 23 sources yielding a ~90% detection rate for this survey; in 12 of
these sources we detect multiple lines, while in 11 sources we detect only a
single line. For the sources with only one detected line, we break the redshift
degeneracy with additional spectroscopic observations if available, or infer
the most likely line identification based on photometric data. This yields
secure redshifts for ~70% of the sample. The three sources with no lines
detected are tentatively placed in the redshift desert between 1.7<z<2.0. The
resulting mean redshift of our sample is <z>=3.5. This finding is in contrast
to the redshift distribution of radio-identified DSFGs, which have a
significantly lower mean redshift of <z>=2.3 and for which only 10-15% of the
population is expected to be at z>3. We discuss the effect of gravitational
lensing on the redshift distribution and compare our measured redshift
distribution to that of models in the literature.


title:
Topological phase transition in a generalized Kane-Mele-Hubbard model: A
  combined Quantum Monte Carlo and Green's function study

abstract:
  We study a generalized Kane-Mele-Hubbard model with third-neighbor hopping,
an interacting two-dimensional model with a topological phase transition as a
function of third-neighbor hopping, by means of the determinant projector
Quantum Monte Carlo (QMC) method. This technique is essentially numerically
exact on models without a fermion sign problem, such as the one we consider. We
determine the interaction-dependence of the Z2 topological insulator/trivial
insulator phase boundary by calculating the Z2 invariants directly from the
single-particle Green's function. The interactions push the phase boundary to
larger values of third-neighbor hopping, thus stabilizing the topological
phase. The observation of boundary shifting entirely stems from quantum
{\deg}uctuations. We also identify qualitative features of the single-particle
Green's function which are computationally useful in numerical searches for
topological phase transitions without the need to compute the full topological
invariant.


title: On shrinking Gradient Ricci Soliton With Nonnegative Sectional Curvature

abstract:
  In this paper, we prove some rigidity theorems for shrinking gradient Ricci
solitons with nonnegative sectional curvature.


title: A note on sumsets of subgroups in $\mathbb Z_p^*$

abstract:
  Let $A$ be a multiplicative subgroup of $\mathbb Z_p^*$. Define the $k$-fold
sumset of $A$ to be $kA=\{x_1+\dots+x_k:x_i \in A,1\leq i\leq k\}$. We show
that $6A\supseteq \mathbb Z_p^*$ for $|A| > p^{\frac {11}{23} +\epsilon}$. In
addition, we extend a result of Shkredov to show that $|2A|\gg |A|^{\frac
85-\epsilon}$ for $|A|\ll p^{\frac 59}$.


title: Is Cheeger-type Approximation Possible for Nonuniform Sparsest Cut?

abstract:
  In the {\em nonuniform sparsest cut} problem, given two undirected graphs $G$
and $H$ over the same set of vertices $V$, we want to find a cut $(S,V-S)$ that
minimizes the ratio between the fraction of $G$-edges that are cut and the
fraction of $H$-edges that are cut. The ratio (which is at most 1 in an optimal
solution) is called the {\em sparsity} of the cut. In the {\em uniform sparsest
cut} problem, $H$ is a clique over $V$. If $G$ is regular, it is possible to
find a solution to the uniform sparsest cut of cost $O(\sqrt{opt})$ in nearly
linear time. Is such an approximation, which we call "Cheege-type"
approximation, achievable in the non-uniform case?
  We show that the answer is negative, assuming the Unique Games Conjecture,
for general H. Furthermore, the Leighton-Rao linear programming relaxation and
the spectral relaxation fail to find such an approximation even if $H$ is a
clique over a subset of vertices. Using semidefinite programming, however, we
can find Cheeger-type approximations in polynomial time whenever the adjacency
matrix of $H$ has rank 1. (This includes the cases in which $H$ is a clique
over a subset of vertices.)


title: Hyperbolicity of linear partial differential equations with delay

abstract:
  Robust hyperbolicity and stability results for linear partial differential
equations with delay will be given and, as an application, the effect of small
delays to the asymptotic properties of feedback systems will be analyzed.


title: Higgs Boson -- on Your Own

abstract:
  One of the highlights of 2012 in physics is related to two papers, published
by the ATLAS and the CMS Collaborations, that announced the discovery of at
least one new particle in pp collisions at CERN LHC. At least one of the
properties of this new particle is found to be similar to that of the Higgs
boson, the last and most difficult to find building block from the Standard
Model of particle physics. Physics teachers are frequently approached by their
media-educated students, who inquire about the properties of the Higgs boson,
but physics teachers are rarely trained to teach this elusive aspect of
particle physics in elementary, middle or junior high schools. In this paper I
describe a card-game, that can be considered as a hands-on and easily
accessible tool that allows interested teachers, students and also motivated
lay-persons to play with the properties of the newly found Higgs-like particle.
This new particle was detected through its decays to directly observable, final
state particles. Many of these final state particles are represented in a deck
of cards, that represent elementary particles, originally invented to
popularize the physics of quark matter in the so-called Quark Matter Card
Games. The Higgs decay properties can be utilized, playfully, in a Higgs boson
search card game. The rules of this game illustrate also the need for some
luck, to complement knowledge and memory, useful skills that this game also
helps to develop. The paper is organized as a handout or booklet, that directly
describes how to play the Higgs boson on Your Own card game.

categories: physics.pop-ph hep-ex nucl-ex physics.ed-ph


title:
Search of the Earth Limb Fermi Data and Non-Galactic Center Region Fermi
  Data for Signs of Narrow Lines

abstract:
  Since the spring of 2012 there have been many papers published using Fermi
LAT public data that claim evidence for narrow spectral lines coming from the
region of the Galactic center. This study uses non-Galactic center Fermi-LAT
data from survey mode observations, and Earth limb Fermi data to test the dark
matter interpretation of this feature and better understand its origins.


title: Some phenomenological aspects of a new $U(1)'$ model

abstract:
  We propose a new non-universal $U(1)'$ extension of the standard model with
the addition of three exotic quark singlets, two scalar singlets and one
additional scalar doublet. We obtain family dependent couplings with a new $Z'$
boson in the quark sector and universal couplings with the lepton sector. From
experimental data on $Z'$ research at CERN-LHC collider, we find limit regions
in the $U(1)'$ free parameters ($Z'$ mass and coupling constant), which we use
to obtain total decay width and invariant-mass distributions. By introducing
discrete symmetries and mixing couplings between ordinary and exotic fermions,
we obtain predictable mass relations in the quark sector compatible with the
phenomenological values without large fine tuning of the Yukawa couplings and
with few free parameters, where hierarchies between quark families can be
understood from the existence of heavy beyond standard model particles.


title: Efficient Codes for Limited View Adversarial Channels

abstract:
  We introduce randomized Limited View (LV) adversary codes that provide
protection against an adversary that uses their partial view of the
communication to construct an adversarial error vector to be added to the
channel. For a codeword of length N, the adversary selects a subset of \rho_rN
of the codeword components to "see", and then "adds" an adversarial error
vector of weight \rho_wN to the codeword. Performance of the code is measured
by the probability of the decoder failure in recovering the sent message. An
(N, q^{RN},\delta)-limited view adversary code ensures that the success chance
of the adversary in making decoder fail, is bounded by \delta when the
information rate of the code is at least R. Our main motivation to study these
codes is providing protection for wireless communication at the physical layer
of networks.
  We formalize the definition of adversarial error and decoder failure,
construct a code with efficient encoding and decoding that allows the adversary
to, depending on the code rate, read up to half of the sent codeword and add
error on the same coordinates. The code is non-linear, has an efficient
decoding algorithm, and is constructed using a message authentication code
(MAC) and a Folded Reed-Solomon (FRS) code. The decoding algorithm uses an
innovative approach that combines the list decoding algorithm of the FRS codes
and the MAC verification algorithm to eliminate the exponential size of the
list output from the decoding algorithm. We discuss application of our results
to Reliable Message Transmission problem, and open problems for future work.


title: Nuclei as Probes of Meson-Nucleon Interactions at High and Low Energy

abstract:
  This dissertation explores two main topics: 1) Color Transparency and
quasi-elastic knockout reactions involving pions and $\rho$ mesons; and 2)
determination of the $J/\psi$-nucleon scattering amplitude and scattering
length via $J/\psi$ electroproduction on the deuteron. It is shown that at the
energies available at the COMPASS experiment at CERN, Color Transparency should
be detectable in the reaction $\pi+A\to \pi+p+(A-1)^*$ (proton knockout). It is
also shown that Color Transparency should be detectable in the
electroproduction reaction $\gamma^*+A\to\rho+p+(A-1)^*$ at small $Q^2$ (where
$Q^2$ is the virtuality of the photon) but large $t$ (4-momentum transfer
squared to the knocked out proton), which represents an as-yet unexplored
kinematic region in the search for CT effects in electroproduction of vector
mesons. Calculations are also presented for the reaction $\gamma^*+D\to
J/\psi+p+n$ at JLab energies in order to determine the feasibility of measuring
the elastic $J/\psi$-nucleon scattering amplitude and/or scattering length. It
is found that it may be possible to measure the $J/\psi$-nucleon scattering
amplitude at lower energies than previous measurements, but the scattering
length cannot be measured.


title:
In-Plane Magnetic Field Tolerance of a Dispersive Aluminum Nanobridge
  SQUID Magnetometer

abstract:
  We characterize the flux sensitivity of a dispersive 3D aluminum nanobridge
SQUID magnetometer as a function of applied in-plane magnetic field. In zero
field, we observe an effective flux noise of 17 n$\Phi_0$/Hz$^{1/2}$ with 25
MHz of bandwidth. Flux noise increased by less than a factor of three with
parallel magnetic fields up to 61 mT. Operation in higher fields may be
possible by decreasing the dimensions of the shunt capacitor in the
magnetometer circuit. These devices are thus well suited for observing
high-speed dynamics in nanoscale magnets, even in the presence of moderate bias
magnetic fields.


title:
Nonlinear dynamics of antihydrogen in magnetostatic traps: implications
  for gravitational measurements

abstract:
  The influence of gravity on antihydrogen dynamics in magnetic traps is
studied. The advantages and disadvantages of various techniques for measuring
the ratio of the gravitational mass to the inertial mass of antihydrogen are
discussed. Theoretical considerations and numerical simulations indicate that
stochasticity may be especially important for some experimental techniques in
vertically oriented traps.


title: Machine Learning for Bioclimatic Modelling

abstract:
  Many machine learning (ML) approaches are widely used to generate bioclimatic
models for prediction of geographic range of organism as a function of climate.
Applications such as prediction of range shift in organism, range of invasive
species influenced by climate change are important parameters in understanding
the impact of climate change. However, success of machine learning-based
approaches depends on a number of factors. While it can be safely said that no
particular ML technique can be effective in all applications and success of a
technique is predominantly dependent on the application or the type of the
problem, it is useful to understand their behavior to ensure informed choice of
techniques. This paper presents a comprehensive review of machine
learning-based bioclimatic model generation and analyses the factors
influencing success of such models. Considering the wide use of statistical
techniques, in our discussion we also include conventional statistical
techniques used in bioclimatic modelling.


title: Cosmic R-string in thermal history

abstract:
  We study stabilization of an unstable cosmic string associated with
spontaneously broken $U(1)_R$ symmetry, which otherwise causes a dangerous
roll-over process. We demonstrate that in a gauge mediation model, messengers
can receive enough corrections from the thermal plasma of the supersymmetric
standard model particles to stabilize the unstable modes of the string.


title:
Morphology and photocatalytic activity of highly oriented mixed phase
  titanium dioxide thin films

abstract:
  Thin TiO2 films on quartz substrates were prepared by spin coating of undoped
and metal-ion-doped Sol Gel precursors. These films were characterised by
Scanning Electron Microscopy, Laser Raman Microspectroscopy, Xray Diffraction
and UV Vis Transmission. The photocatalytic performances of the films were
assessed by the photo-degradation of methylene-blue in aqueous solution under
UV irradiation. Films exhibited a high degree of orientation and a thermal
stabilization of the anatase phase as a result of substrate effects. In the
absence of dopants, the rutile phase formed as parallel bands in the anatase
which broadened as the transformation progressed. TiO2 films doped or co-doped
with transition metals exhibited the formation of rutile in segregated clusters
at temperatures under 800C as a result of increased levels of oxygen vacancies.
Photocatalytic activity of the films synthesised in this work was low as likely
a result of poor TiO2 surface contact with dye molecules in the solution. The
presence of transition metal dopants appears detrimental to photocatalytic
activity while the performance of mixed phase films was not observed to differ
significantly from single phase material.


title:
Anodic aqueous electrophoretic deposition of titanium dioxide using
  carboxylic acids as dispersing agents

abstract:
  The dispersion of anatase phase TiO2 powder in aqueous suspensions was
investigated by zeta-potential and agglomerate size analysis. The iso-electric
point (IEP) of anatase was determined to be at pH 2.8 using monoprotic acids
for pH adjustment. In comparison, it was found that the use of carboxylic
acids, citric and oxalic, caused a decrease in zeta-potential through the
adsorption of negatively charged groups to the particle surfaces. The use of
these reagents was shown to enable effective anodic electrophoretic deposition
(EPD) of TiO2 onto graphite substrates at low pH levels with a decreased level
of bubble damage in comparison with anodic EPD from basic suspensions. The
results obtained demonstrate that the IEP of TiO2 varies with the type of
reagent used for pH adjustment. The low pH level of the IEP and the ability to
decrease the zeta-potential through the use of carboxylic acids suggest that
the anodic EPD of anatase is more readily facilitated than cathodic EPD.


title: Worldsheet one-loop energy correction to IIA Giant Magnon

abstract:
  We compute one-loop corrections to the energy of a IIA giant magnon solution
in the $AdS_4 \times CP^3$ background by using the standard quantum field
theory (QFT) techniques. The string action is expanded around the solution to
the quadratic order in the fluctuation fields. The resulting action has 2D
coordinate dependent-coefficients, a feature that complicates the analysis. The
solution contains a worldsheet velocity parameter $v$, and is expanded in terms
of the parameter. A perturbative analysis is carried out by treating the
$v$-dependent parts as vertices. The energy is computed by first putting the
system in a box of length $L$ and Fourier-transforming the fields into the
discrete momentum modes. We compare our result with the results obtained by the
algebraic curve method.


title: Efficient Acceleration of Relativistic Magnetohydrodynamic Jets

abstract:
  Relativistic jets in active galactic nuclei, galactic microquasars, and
gamma-ray bursts are widely considered to be magnetohydrodynamically driven by
black hole accretion systems, although conversion mechanism from Poynting into
particle kinetic energy flux is still open. Recent detailed numerical and
analytical studies of global structures of steady, axisymmetric
magnetohydrodynamic (MHD) flows with specific boundary conditions have not
reproduced as rapid an energy conversion as required by observations. In order
to find more suitable boundary conditions, we focus on the flow along a
poloidal magnetic field line just inside the external boundary, without
treating transfield force balance in detail. We find some examples of the
poloidal field structure and corresponding external pressure profile for an
efficient and rapid energy conversion as required by observations, and that the
rapid acceleration requires a rapid decrease of the external pressure above the
accretion disk. We also clarify the differences between the fast magnetosonic
point of the MHD flow and the sonic point of de Laval nozzle.


title: Evolutionary Approaches to Expensive Optimisation

abstract:
  Surrogate assisted evolutionary algorithms (EA) are rapidly gaining
popularity where applications of EA in complex real world problem domains are
concerned. Although EAs are powerful global optimizers, finding optimal
solution to complex high dimensional, multimodal problems often require very
expensive fitness function evaluations. Needless to say, this could brand any
population-based iterative optimization technique to be the most crippling
choice to handle such problems. Use of approximate model or surrogates provides
a much cheaper option. However, naturally this cheaper option comes with its
own price. This paper discusses some of the key issues involved with use of
approximation in evolutionary algorithm, possible best practices and solutions.
Answers to the following questions have been sought: what type of fitness
approximation to be used; which approximation model to use; how to integrate
the approximation model in EA; how much approximation to use; and how to ensure
reliable approximation.


title: BSG alignment of SDSS galaxy groups

abstract:
  We study the alignment signal between the distribution of brightest satellite
galaxies (BSGs) and the major axis of their host groups using SDSS group
catalog constructed by Yang et al. (2007). After correcting for the effect of
group ellipticity, a statistically significant (~ 5\sigma) major-axis alignment
is detected and the alignment angle is found to be 43.0 \pm 0.4 degrees. More
massive and richer groups show stronger BSG alignment. The BSG alignment around
blue BCGs is slightly stronger than that around red BCGs. And red BSGs have
much stronger major-axis alignment than blue BSGs. Unlike BSGs, other
satellites do not show very significant alignment with group major axis. We
further explore the BSG alignment in semi-analytic model (SAM) constructed by
Guo et al. (2011). We found general good agreement with observations: BSGs in
SAM show strong major-axis alignment which depends on group mass and richness
in the same way as observations; and none of other satellites exhibit prominent
alignment. However, discrepancy also exists in that the SAM shows opposite BSG
color dependence, which is most probably induced by the missing of large scale
environment ingredient in SAM. The combination of two popular scenarios can
explain the detected BSG alignment. The first one: satellites merged into the
group preferentially along the surrounding filaments, which is strongly aligned
with the major axis of the group. The second one: BSGs enter their host group
more recently than other satellites, then will preserve more information about
the assembling history and so the major-axis alignment. In SAM, we found
positive evidence for the second scenario by the fact that BSGs merged into
groups statistically more recently than other satellites. On the other hand,
although is opposite in SAM, the BSG color dependence in observation might
indicate the first scenario as well.


title:
Limits on Violations of Lorentz Symmetry and the Einstein Equivalence
  Principle using Radio-Frequency Spectroscopy of Atomic Dysprosium

abstract:
  We report a joint test of local Lorentz invariance and the Einstein
equivalence principle for electrons, using long-term measurements of the
transition frequency between two nearly degenerate states of atomic dysprosium.
We present many-body calculations which demonstrate that the energy splitting
of these states is particularly sensitive to violations of both special and
general relativity. We limit Lorentz violation for electrons at the level of
$10^{-17}$, matching or improving the best laboratory and astrophysical limits
by up to a factor of 10, and improve bounds on gravitational redshift anomalies
for electrons by 2 orders of magnitude, to $10^{-8}$. With some enhancements,
our experiment may be sensitive to Lorentz violation at the level of $9\times
10^{-20}$.


title:
Relation between standard perturbation theory and regularized
  multi-point propagator method

abstract:
  We investigate the relation between the regularized multi-propagator method,
called "Reg PT", and the standard perturbation theory. Reg PT is one of the
most successful models to describe nonlinear evolution of dark matter
fluctuations. However, Reg PT is a mathematically unproven interpolation
formula between the large-scale solution calculated by the standard
perturbation theory and the limiting solution in the small scale calculated by
the multi-point propagator method. In this paper, we give an alternative
explanation for Reg PT in the context of the standard perturbation theory,
showing that Reg PT does not ever have more effective information on nonlinear
matter evolution than the standard perturbation theory. In other words, the
solutions of the standard perturbation theory reproduce the results of $N$-body
simulations better than those of Reg PT, especially at the high-$k$ region.
This fact means that the standard perturbation theory at the two-loop level is
still one of the best predictions of the nonlinear power spectrum to date.
Nevertheless, the standard perturbation theory has not been preferred because
of the divergent behavior of the solution at small scales. To solve this
problem, we also propose a modified standard perturbation theory which avoids
the divergence.


title: A new inequality on the Hodge number $h^{1,1}$ of algebraic surfaces

abstract:
  We get a new inequality on the Hodge number $h^{1,1}(S)$ of fibred algebraic
complex surfaces $S$, which is a generalization of an inequality of Beauville.
Our inequality implies the Arakelov type inequalities due to Arakelov,
Faltings, Viehweg and Zuo, respectively.


title: Delta-N Formalism for Curvaton with Modulated Decay

abstract:
  In this paper, the curvature perturbation generated by the modulated curvaton
decay is studied by a direct application of $\delta N$-formalism. Our method
has a sharp contrast with the {\it non-linear formalism} which may be regarded
as an indirect usage of $\delta N$-formalism. We first show that our method can
readily reproduce results in previous works of modulation of curvaton. Then we
move on to calculate the case where the curvaton mass (and hence also the decay
rate) is modulated. The method can be applied to the calculation of the
modulation in the freezeout model, in which the heavy species are considered
instead of the curvaton. Our method explains curvaton and various modulation on
an equal footing.


title: Gaussian Mixture Model for Handwritten Script Identification

abstract:
  This paper presents a Gaussian Mixture Model (GMM) to identify the script of
handwritten words of Roman, Devanagari, Kannada and Telugu scripts. It
emphasizes the significance of directional energies for identification of
script of the word. It is robust to varied image sizes and different styles of
writing. A GMM is modeled using a set of six novel features derived from
directional energy distributions of the underlying image. The standard
deviation of directional energy distributions are computed by decomposing an
image matrix into right and left diagonals. Furthermore, deviation of
horizontal and vertical distributions of energies is also built-in to GMM. A
dataset of 400 images out of 800 (200 of each script) are used for training GMM
and the remaining is for testing. An exhaustive experimentation is carried out
at bi-script, tri-script and multi-script level and achieved script
identification accuracies in percentage as 98.7, 98.16 and 96.91 respectively.


title: Bounding the dimensions of rational cohomology groups

abstract:
  Let $k$ be an algebraically closed field of characteristic $p > 0$, and let
$G$ be a simple simply-connected algebraic group over $k$ that is defined and
split over the prime field $\mathbb{F}_p$. In this paper we investigate
situations where the dimension of a rational cohomology group for $G$ can be
bounded by a constant times the dimension of the coefficient module. We then
demonstrate how our results can be applied to obtain effective bounds on the
first cohomology of the symmetric group. We also show how, for finite Chevalley
groups, our methods permit significant improvements over previous estimates for
the dimensions of second cohomology groups.


title: On Choosability with Separation of Planar Graphs with Forbidden Cycles

abstract:
  We study choosability with separation which is a constrained version of list
coloring of graphs. A (k,d)-list assignment L on a graph G is a function that
assigns to each vertex v a list L(v) of at least k colors and for any adjacent
pair xy, the lists L(x) and L(y) share at most d colors. A graph G is
(k,d)-choosable if there exists an L-coloring of G for every (k,d)-list
assignment L. This concept is also known as choosability with separation. We
prove that planar graphs without 4-cycles are (3,1)-choosable and that planar
graphs without 5-cycles and 6-cycles are (3,1)-choosable. In addition, we give
an alternative and slightly stronger proof that triangle-free planar graphs are
$(3,1)$-choosable.


title:
The effects of carboxylic acids on the aqueous dispersion and
  electrophoretic deposition of ZrO2

abstract:
  The agglomeration, electrokinetic properties and electrophoretic deposition
behaviour of aqueous suspensions of ZrO2 with carboxylic acid additives were
studied in comparison with conventional pH adjustment. It was found that citric
acid imparted negative zeta-potential values and electrosteric stabilisation to
particles in suspensions at all pH levels. The examination of additions of
carboxylic acids to ZrO2 suspensions revealed that these reagents cause a sharp
drop in zeta-potential at distinct addition levels, which correspond to surface
saturation of the particles with negatively charged carboxylate groups.
Adsorption cross sections of citric acid, EDTA and oxalic acid were evaluated
from these results, showing that both citric acid and EDTA coordinate to ZrO2
surfaces by two carboxylate groups while oxalic acid is coordinated by one
group. The use of carboxylic acids was shown to facilitate superior
electrophoretic deposition in comparison with zeta-potential modification by
conventional pH adjustment through improved suspension stability.


title:
Star formation in the massive "starless" infrared dark cloud
  G0.253$+$0.016

abstract:
  G0.253+0.016 is a remarkable massive infrared dark cloud located within
$\sim$100 pc of the galactic center. With a high mass of $1.3 \times 10^5
M_\odot$, a compact average radius of $\sim$2.8 pc and a low dust temperature
of 23 K, it has been believed to be a yet starless precursor to a massive
Arches-like stellar cluster. We present sensitive JVLA 1.3 and 5.6 cm radio
continuum observations that reveal the presence on three compact thermal radio
sources projected against this cloud. These radio sources are interpreted as
HII regions powered by $\sim$B0.5 ZAMS stars. We conclude that although
G0.253+0.016 does not show evidence of O-type star formation, there are
certainly early B-type stars embedded in it. We detect three more sources in
the periphery of G0.253+0.016 with non-thermal spectral indices. We suggest
that these sources may be related to the galactic center region and deserve
further study.


title:
Protecting dissipative quantum state preparation via dynamical
  decoupling

abstract:
  We show that dissipative quantum state preparation processes can be protected
against qubit dephasing by interlacing the state preparation control with
dynamical decoupling (DD) control consisting of a sequence of short
$\pi$-pulses. The inhomogeneous broadening can be suppressed to second order of
the pulse interval, and the protection efficiency is nearly independent of the
pulse sequence but determined by the average interval between pulses. The DD
protection is numerically tested and found to be efficient against
inhomogeneous dephasing on two exemplary dissipative state preparation schemes
that use collective pumping to realize many-body singlets and linear cluster
states respectively. Numerical simulation also shows that the state preparation
can be efficiently protected by $\pi$-pulses with completely random arrival
time. Our results make possible the application of these state preparation
schemes in inhomogeneously broadened systems. DD protection of state
preparation against dynamical noises is also discussed using the example of
Gaussian noise with a semiclasscial description.


title:
The effects of firing conditions on the properties of
  electrophoretically deposited titanium dioxide films on graphite substrates

abstract:
  Thick anatase films were fabricated on graphite substrates using a method of
anodic aqueous electrophoretic-deposition using oxalic acid as a dispersant.
Thick films were subsequently fired in air and in nitrogen at a range of
temperatures. The morphology and phase composition were assessed and the
photocatalytic performance was examined by the inactivation of Escherichia coli
in water. It was found that the transformation of anatase to rutile is enhanced
by the presence of a graphite substrate through reduction effects. The use of a
nitrogen atmosphere allows higher firing temperatures, results in less cracking
of the films and yields superior bactericidal performance in comparison with
firing in air. The beneficial effects of a nitrogen firing atmosphere on the
photocatalytic performance of the material are likely to be a result of the
diffusion of nitrogen and carbon into the TiO2 lattice and the consequent
creation of new valence band states.


title:
Formation of Dense Molecular Gas and Stars at the Circumnuclear
  Starburst Ring in the Barred Galaxy NGC 7552

abstract:
  We present millimeter molecular-line complemented by optical observations,
along with a reanalysis of archival centimeter HI and continuum data, to infer
the global dynamics and determine where dense molecular gas and massive stars
preferentially form in the circumnuclear starburst ring of the barred-spiral
galaxy NGC 7552. We find diffuse molecular gas in a pair of dust lanes each
running along the large-scale galactic bar, as well as in the circumnuclear
starburst ring. We do not detect dense molecular gas in the dust lanes, but
find such gas concentrated in two knots where the dust lanes make contact with
the circumnuclear starburst ring. When convolved to the same angular resolution
as the images in dense gas, the radio continuum emission of the circumnuclear
starburst ring also exhibits two knots, each lying downstream of an adjacent
knot in dense gas. The results agree qualitatively with the idea that massive
stars form from dense gas at the contact points, where diffuse gas is channeled
into the ring along the dust lanes, and later explode as supernovae downstream
of the contact points. Based on the inferred rotation curve, however, the
propagation time between the respective pairs of dense gas and centimeter
continuum knots is about an order of magnitude shorter than the lifetimes of OB
stars. We discuss possible reasons of this discrepancy, and conclude that
either the initial mass function is top-heavy or massive stars in the ring do
not form exclusively at the contact points where dense molecular gas is
concentrated.


title: Atomic decompositions of Besov spaces related to symmetric cones

abstract:
  In this paper we extend the atomic decompositions previously obtained for
Besov spaces related to the forward light cone to general symmetric cones. We
do so via wavelet theory adapted to the cone. The wavelet transforms sets up an
isomorphism between the Besov spaces and certain reproducing kernel function
spaces on the group, and sampling of the transformed data will provide the
atomic decompositions and frames for the Besov spaces.


title:
A Novel Description of Linear Time--Invariant Networks via Structured
  Coprime Factorizations

abstract:
  In this paper we study state-space realizations of Linear and Time-Invariant
(LTI) systems. Motivated by biochemical reaction networks, Gon\c{c}alves and
Warnick have recently introduced the notion of a {\em Dynamical Structure
Functions} (DSF), a particular factorization of the system's transfer function
matrix that elucidates the interconnection structure in dependencies between
manifest variables. We build onto this work by showing an intrinsic connection
between a DSF and certain sparse left coprime factorizations. By establishing
this link, we provide an interesting systems theoretic interpretation of
sparsity patterns of coprime factors. In particular we show how the sparsity of
these coprime factors allows for a given LTI system to be implemented as a
network of LTI sub-systems. We examine possible applications in distributed
control such as the design of a LTI controller that can be implemented over a
network with a pre-specified topology.


title: Abnormal grain growth of rutile TiO2 induced by ZrSiO4

abstract:
  Abnormal grain growth (AGG) was observed in rutile TiO2 formed by the thermal
treatment of anatase TiO2 in the presence of zirconium silicate. This
morphological behaviour was seen to occur in sintered powder compacts and thin
films with solid state zircon dopants and in TiO2 coatings on grains of zircon
sand. In order to clarify the mechanism of AGG in this system, various doping
methods were employed and the morphological consequences of these doping
methods were investigated. It was found that doping by Zr and Si does not give
rise to abnormal grain growth. The observed phenomena were discussed in terms
of morphological and energetic considerations. It is likely that a distinct
orientation relationship between rutile TiO2 and ZrSiO4 and possible grain
boundary liquid formation play a role in giving rise to the rapid growth of
faceted prismatic rutile.


title: Old and new algorithms for pi

abstract:
  This is a letter to the editor concerning Semjon Adlaj's article "An eloquent
formula for the perimeter of an ellipse", AMS Notices 59, 8 (2012), 1094-1099.


title: Functors given by kernels, adjunctions and duality

abstract:
  Let X_1 and X_2 be schemes of finite type over a field of characteristic 0.
Let Q be an object in the category D-mod(X_1\times X_2) and consider the
functor F:D-mod(X_1)->Dmod(X_2) defined by Q. Assume that F admits a right
adjoint also defined by an object P in D-mod(X_1\times X_2). The question that
we pose and answer in this paper is how P is related to the Verdier dual of Q.
We subsequently generalize this question to the case when X_1 and X_2 are no
longer schemes but Artin stacks, where the situation becomes much more
interesting.


title:
Research and Simulation on Drivers' Route Choice Behavior Cognition
  Model

abstract:
  This paper studied the behavior-cognitive model of drivers during their
travel based on the current research on driver behavior. Firstly, a route
choice behavior-cognitive model was proposed for describing the decision-making
mechanism of drivers during his travel; then, simulation experiments were
carried out on the cosimulation VBc-vissim platform. From the experimental
results, dynamic behavior features of drivers during their travel can be
properly explained by the behavior-cognitive model, thus optimal path can be
obtained from this model.


title:
Superheavy magic structures in the relativistic Hartree-Fock-Bogoliubov
  approach

abstract:
  We have explored the occurrence of the spherical shell closures for
superheavy nuclei in the framework of the relativistic Hartree-Fock-Bogoliubov
(RHFB) theory. Shell effects are characterized in terms of two-nucleon gaps
$\delta_{2n(p)}$. Although the results depend slightly on the effective
Lagrangians used, the general set of magic numbers beyond $^{208}$Pb are
predicted to be $Z = 120$, $138$ for protons and $N = 172$, 184, 228 and 258
for neutrons, respectively. Specifically the RHFB calculations favor the
nuclide $^{304}$120 as the next spherical doubly magic one beyond $^{208}$Pb.
Shell effects are sensitive to various terms of the mean-field, such as the
spin-orbit coupling, the scalar and effective masses.


title:
Optimized Transmission with Improper Gaussian Signaling in the K-User
  MISO Interference Channel

abstract:
  This paper studies the achievable rate region of the K-user Gaussian
multiple-input single-output interference channel (MISO-IC) with the
interference treated as noise, when improper or circularly asymmetric complex
Gaussian signaling is applied. The transmit optimization with improper Gaussian
signaling involves not only the signal covariance matrix as in the conventional
proper or circularly symmetric Gaussian signaling, but also the signal
pseudo-covariance matrix, which is conventionally set to zero in proper
Gaussian signaling. By exploiting the separable rate expression with improper
Gaussian signaling, we propose a separate transmit covariance and
pseudo-covariance optimization algorithm, which is guaranteed to improve the
users' achievable rates over the conventional proper Gaussian signaling. In
particular, for the pseudo-covariance optimization, we establish the optimality
of rank-1 pseudo-covariance matrices, given the optimal rank-1 transmit
covariance matrices for achieving the Pareto boundary of the rate region. Based
on this result, we are able to greatly reduce the number of variables in the
pseudo-covariance optimization problem and thereby develop an efficient
solution by applying the celebrated semidefinite relaxation (SDR) technique.
Finally, we extend the result to the Gaussian MISO broadcast channel (MISO-BC)
with improper Gaussian signaling or so-called widely linear transmit precoding.


title:
Vortex lock-in transition and evidence for transitions among
  commensurate kinked vortex configurations in single-layered Fe arsenides

abstract:
  We report an angle-dependent study of the magnetic torque $\tau(\theta)$
within the vortex state of single-crystalline LaO$_{0.9}$F$_{0.1}$FeAs and
SmO$_{0.9}$F$_{0.1}$FeAs as a function of both temperature $T$ and magnetic
field $H$. Sharp peaks are observed at a critical angle $\theta_c$ at either
side of $\theta=90^{\circ}$, where $\theta$ is the angle between $H$ and the
inter-planar \emph{c}-axis. $\theta_c$ is interpreted as the critical depinning
angle where the vortex lattice, pinned and locked by the intrinsic planar
structure, unlocks and acquires a component perpendicular to the planes. We
observe a series of smaller replica peaks as a function of $\theta$ and as
$\theta$ is swept away from the planar direction. These suggest
commensurability effects between the period of the vortex lattice and the
inter-planar distance leading to additional kinked vortex configurations.


abstract:
  Temporal decorrelations in compressible isotropic turbulence are studied
using the space-time correlation theory and direct numerical simulation. A
swept-wave model is developed for dilatational components while the classic
random sweeping model is proposed for solenoidal components. The swept-wave
model shows that the temporal decorrelations in dilatational fluctuations are
dominated by two physical processes: random sweeping and wave propagation.
These models are supported by the direct numerical simulation of compressible
isotropic turbulence, in the sense of that all curves of normalized time
correlations for different wavenumbers collapse into a single one using the
normalized time separations. The swept-wave model is further extended to
account for a constant mean velocity.


title: Redeeming Bad Theories

abstract:
  We give a Seiberg-like dual description of the interacting superconformal
infrared fixed point of $\mathcal{N}=4$ gauge theory in three dimensions with
vanishing Chern Simons level and $N_c\le N_f<2N_c$ fundamental flavors. These
theories are known as "bad" theories due to the existence of unitarity
violating monopole operators. We show that, in a dual description, all such
operators are realized by free fields and the remainder theory is the
Seiberg-like dual previously identified using the type IIB brane construction.


title: Signed Graphs and Geometry

abstract:
  These lecture notes are a personal introduction to signed graphs,
concentrating on the aspects that have been most persistently interesting to
me. They are just a few corners of signed graph theory; I am leaving out a
great deal. The emphasis is on the way signed graphs arise naturally from
geometry, especially from the geometry of the classical root systems. Most of
the properties I discuss generalize those of unsigned graphs, but the
constructions and proofs are often more complicated. My aim is a coherent
presentation of the subject, with a few illustrative proofs and adequate
references. Hence the arrangement of the notes is topical with only occasional
remarks about the historical course of development. Though this is mainly an
expository survey, some of the results have not hitherto been published.


title:
Progress Towards Opto-Electronic Characterization of Indium Phosphide
  Nanowire Transistors at milli-Kelvin temperatures

abstract:
  In this paper we present our progress towards the opto-electronic
characterization of indium phosphide (InP) nanowire transistors at milli-Kelvin
(mK) temperatures. First, we have investigated the electronic transport of the
InP nanowires by current-voltage (I-V) spectroscopy as a function of
temperature from 300 K down to 40 K. Second, we show the successful operation
of a red light emitting diode (LED) at liquid-Helium (and base) temperature to
be used for opto-electronic device characterization.


title: Further analysis of the binary Euclidean algorithm

abstract:
  The binary Euclidean algorithm is a variant of the classical Euclidean
algorithm. It avoids multiplications and divisions, except by powers of two, so
is potentially faster than the classical algorithm on a binary machine. We
describe the binary algorithm and consider its average case behaviour. In
particular, we correct some errors in the literature, discuss some results of
Vall\'ee, and describe a numerical computation which supports a conjecture of
Vall\'ee.


title: BTZ Black Hole Entropy in Loop Quantum Gravity and in Spin Foam Models

abstract:
  We present a comparison of the calculation of BTZ black hole entropy in loop
quantum gravity and in spin foam models. We see that both give the same answer.


title:
Joint Beamforming and Power Control in Coordinated Multicell: Max-Min
  Duality, Effective Network and Large System Transition

abstract:
  This paper studies joint beamforming and power control in a coordinated
multicell downlink system that serves multiple users per cell to maximize the
minimum weighted signal-to-interference-plus-noise ratio. The optimal solution
and distributed algorithm with geometrically fast convergence rate are derived
by employing the nonlinear Perron-Frobenius theory and the multicell network
duality. The iterative algorithm, though operating in a distributed manner,
still requires instantaneous power update within the coordinated cluster
through the backhaul. The backhaul information exchange and message passing may
become prohibitive with increasing number of transmit antennas and increasing
number of users. In order to derive asymptotically optimal solution, random
matrix theory is leveraged to design a distributed algorithm that only requires
statistical information. The advantage of our approach is that there is no
instantaneous power update through backhaul. Moreover, by using nonlinear
Perron-Frobenius theory and random matrix theory, an effective primal network
and an effective dual network are proposed to characterize and interpret the
asymptotic solution.


title:
Finite-size scaling behavior of Bose-Einstein condensation in the 1D
  Bose gas

abstract:
  Through exact numerical solutions we show Bose-Einstein condensation (BEC)
for the one-dimensional (1D) bosons with repulsive short-range interactions at
zero temperature by taking a particular large size limit. Following the
Penrose-Onsager criterion of BEC, we define condensate fraction by the fraction
of the largest eigenvalue of the one-particle reduced density matrix. % We show
the finite-size scaling behavior such that condensate fraction is given by a
scaling function of one-variable: interaction parameter multiplied by a power
of particle number. Condensate fraction is nonzero and constant for any large
value of particle number or system size, if the interaction parameter is
proportional to the negative power of particle number. %Here the interaction
parameter is defined by the coupling constant of the delta-function potentials
devided by the density. %With the scaling behavior we derive various
themodynamic limits where condensate fraction is constant for any large system
size; for instance, it is the case even in the system of a finite particle
number.


title: Lesson learned from (some) recurrent novae

abstract:
  In this talk we present early decline and nebular spectra of the recurrent
novae YY Dor and nova LMC 2009. These and a few other recurrent novae of the
same type, share similar spectral characteristics and evolution. We will
critically discuss those common features suggesting same white dwarf progenitor
and post outburst phases for all of them.


title: The multiple periods and the magnetic nature of CP Pup

abstract:
  Fast cadence time resolved spectra taken at the CTIO-4m telescope with the
RC-spectrograph during 2 consecutive nights revealed a long term modulation of
the binary radial velocity. Chandra hard X-ray spectra taken with the HETGS
instrument showed features typically observed in magnetic white dwarfs (WD).
Here, we present the new data and suggest that CP Pup is possibly a long
orbital period intermediate polar.


title:
Nonclasscial interference between independent intrinsically pure single
  photons at telecom wavelength

abstract:
  We demonstrate a Hong-Ou-Mandel interference between two independent,
intrinsically pure, heralded single photons from spontaneous parametric down
conversion (SPDC) at telecom wavelength. A visibility of $85.5\pm8.3%$ was
achieved without using any bandpass filter. Thanks to the
group-velocity-matched SPDC and superconducting nanowire single photon
detectors (SNSPDs), the 4-fold coincidence counts are one order higher than
that in the previous experiments. The combination of bright single photon
sources and SNSPDs is a crucial step for future practical quantum
info-communication systems at telecom wavelength.


title: Point Set Isolation Using Unit Disks is NP-complete

abstract:
  We consider the situation where one is given a set S of points in the plane
and a collection D of unit disks embedded in the plane. We show that finding a
minimum cardinality subset of D such that any path between any two points in S
is intersected by at least one disk is NP-complete. This settles an open
problem raised by Matt Gibson et al[1]. Using a similar reduction, we show that
finding a minimum cardinality subset D' of D such that R^2 - (D - D') consists
of a single connected region is also NP-complete. Lastly, we show that the
Multiterminal Cut Problem remains NP-complete when restricted to unit disk
graphs.


title:
Entangled state generation with an intrinsically pure single-photon
  source and a weak coherent source

abstract:
  We report on the experimental generation of an entangled state with a
spectrally pure heralded single-photon state and a weak coherent state. By
choosing group-velocity matching in the nonlinear crystal, our system for
producing entangled photons was 60 times brighter than that in the earlier
experiment [Phys. Rev. Lett. 90, 240401 (2003)], with no need of bandpass
filters. This entanglement system is useful for quantum information protocols
that require indistinguishable photons from independent sources.


title:
Proximity effects in a topological-insulator/Mott-insulator
  heterostructure

abstract:
  We investigate proximity effects in a correlated heterostructure of a
two-dimensional Mott insulator (MI) and a topological insulator (TI) by
employing inhomogeneous dynamical mean-field theory. We show that the edge
state of the TI induces strongly renormalized mid-gap states inside the MI
region, which still have a remnant of the helical energy-spectrum. The
penetration of low-energy electrons, which is controlled by the interface
tunneling $V$, largely enhances the electron mass inside the MI and also splits
a single Dirac-cone at edge sites into the spatially-separated two Dirac-cones
in the strong $V$ region.


title: Variation of Hodge structures, Frobenius manifolds and Gauge theory

abstract:
  We explain the homological relation between the Frobenius structure on the
deformation space of Calabi-Yau manifold and the gauge theory of
Kodaira-Spencer gravity. We show that the genus zero generating function of
descendant invariants on Calabi-Yau manifolds from Barannikov's semi-infinite
variation of Hodge structures is equivalent to the Kodaira-Spencer gauge theory
at tree level.


title:
Combined Learning of Salient Local Descriptors and Distance Metrics for
  Image Set Face Verification

abstract:
  In contrast to comparing faces via single exemplars, matching sets of face
images increases robustness and discrimination performance. Recent image set
matching approaches typically measure similarities between subspaces or
manifolds, while representing faces in a rigid and holistic manner. Such
representations are easily affected by variations in terms of alignment,
illumination, pose and expression. While local feature based representations
are considerably more robust to such variations, they have received little
attention within the image set matching area. We propose a novel image set
matching technique, comprised of three aspects: (i) robust descriptors of face
regions based on local features, partly inspired by the hierarchy in the human
visual system, (ii) use of several subspace and exemplar metrics to compare
corresponding face regions, (iii) jointly learning which regions are the most
discriminative while finding the optimal mixing weights for combining metrics.
Face recognition experiments on LFW, PIE and MOBIO face datasets show that the
proposed algorithm obtains considerably better performance than several recent
state-of-the-art techniques, such as Local Principal Angle and the Kernel
Affine Hull Method.


title:
Using State Infection Conditions to Detect Equivalent Mutants and Speed
  up Mutation Analysis

abstract:
  Mutation analysis evaluates test suites and testing techniques by measuring
how well they detect seeded defects (mutants). Even though well established in
research, mutation analysis is rarely used in practice due to scalability
problems --- there are multiple mutations per code statement leading to a large
number of mutants, and hence executions of the test suite. In addition, the use
of mutation to improve test suites is futile for mutants that are equivalent,
which means that there exists no test case that distinguishes them from the
original program.
  This paper introduces two optimizations based on state infection conditions,
i.e., conditions that determine for a test execution whether the same execution
on a mutant would lead to a different state. First, redundant test execution
can be avoided by monitoring state infection conditions, leading to an overall
performance improvement. Second, state infection conditions can aid in
identifying equivalent mutants, thus guiding efforts to improve test suites.


title:
Metaplectic tensor products for automorphic representations of
  $\widetilde{GL}(r)$

abstract:
  Let $M=GL_{r_1}\times\cdots\times GL_{r_k}\subseteq GL_r$ be a Levi subgroup
of $GL_r$, where $r=r_1+\cdots+r_k$, and $\tilde{M}$ its metaplectic preimage
in the metaplectic cover $\tilde{GL}_r$ of $GL_r$. For automorphic
representations $\pi_1,\dots,\pi_k$ of
$\tilde{GL}_{r_1}(\A),\dots,\tilde{GL}_{r_k}(\A)$, we construct an automorphic
representation $\pi$ of $\tilde{M}(\A)$ which can be considered as the "tensor
product" of the representations $\pi_1,\dots,\pi_k$. This is the global
analogue of the metaplectic tensor product defined by P. Mezo in the sense that
locally at each place $v$, $\pi_v$ is equivalent to the local metaplectic
tensor product of ${\pi_1}_v,\dots,{\pi_k}_v$ defined by Mezo. Then we show
that if all of $\pi_i$ are cuspidal (resp. square-integrable modulo center),
then the metaplectic tensor product is cuspidal (resp. square-integrable modulo
center). We also show that (both locally and globally) the metaplectic tensor
product behaves in the expected way under the action of a Weyl group element,
and show the compatibility with parabolic inductions.


title: Formation of Coronal Shock Waves

abstract:
  Numerical simulations of magnetosonic wave formation driven by an expanding
cylindrical piston are performed to get better physical insight into the
initiation and evolution of large-scale coronal waves. Several very basic
initial configurations are employed to analyze intrinsic characteristics of the
MHD wave formation that do not depend on specific properties of the
environment. It turns out that these simple initial configurations result in
piston/wave morphologies and kinematics that reproduce common characteristics
of coronal waves. In the initial stage the wave and the expanding source-region
cannot be clearly resolved. During the acceleration stage of the source-region
inflation, the wave is driven by the piston expansion, so its amplitude and
phase-speed increase, whereas the wavefront profile steepens. At a given point,
a discontinuity forms in the wavefront profile. The time/distance required for
the shock formation is shorter for a more impulsive source-region expansion.
After the piston stops, the wave amplitude and phase-speed start decreasing.
During the expansion, most of the source region becomes strongly rarified,
which reproduces the coronal dimming left behind the eruption. On the other
hand, the density increases at the source-region boundary, and stays enhanced
even after the expansion stops, which might explain stationary brightenings
that are sometimes observed at the edges of the erupted coronal structure. In
addition, in the rear of the wave a weak density depletion develops, trailing
the wave, which is sometimes observed as weak transient coronal dimming.
Finally, we find a well defined relationship between the impulsiveness of the
source-region expansion and the wave amplitude and phase speed. The results for
the cylindrical piston are also compared with the outcome for a planar wave, to
find out how different geometries affect the evolution of the wave.


title:
Role of rotation and polar cap current on pulsar radio emission and
  polarization

abstract:
  The perturbations such as rotation and PC--current have been believed to be
greatly affecting the pulsar radio emission and polarization. The two effects
have not been considered simultaneously in the literature, however, each one of
these has been considered separately and deduced the picture by simply
superposing them, but such an approach can lead to spurious results. Hence by
considering pulsar rotation and PC--current perturbations together instead of
one at a time we have developed a single particle curvature radiation model,
which is expected to be much more realistic. By simulating a set of typical
pulse profiles we have made an attempt to explain most of the observational
results on pulsar radio emission and polarization. The model predicts that due
to the perturbations leading side component can become either stronger or
weaker than the corresponding trailing one in any given cone depending on the
passage of sight line and modulation (nonuniform source distribution). Further
we find that the phase delay of polarization angle inflection point with
respect to the core component greatly depends upon the viewing geometry. The
correlation between the sign reversal of circular polarization and the
polarization angle swing in the case of core dominated pulsars become obscure
once the perturbations and modulation become significant. However the
correlation that the negative circular polarization associates with the
increasing polarization angle and vice versa shows up very clearly in the case
of conal-double pulsars. The `kinky' type distortions in polarization angle
swing could be due to the incoherent superposition of modulated emissions in
the presence of strong perturbations.


title: Exact Mapping between Tensor and Most General Scalar Power Spectra

abstract:
  We prove an exact relation between the tensor and the scalar primordial power
spectra generated during inflation. Such a mapping considerably simplifies the
derivation of any power spectra as they can be obtained from the study of the
tensor modes only, which are much easier to solve. As an illustration, starting
from the second order slow-roll tensor power spectrum, we derive in a few lines
the next-to-next-to-leading order power spectrum of the comoving curvature
perturbation in generalized single field inflation with a varying speed of
sound.


title:
A Cooperative Q-learning Approach for Real-time Power Allocation in
  Femtocell Networks

abstract:
  In this paper, we address the problem of distributed interference management
of cognitive femtocells that share the same frequency range with macrocells
(primary user) using distributed multi-agent Q-learning. We formulate and solve
three problems representing three different Q-learning algorithms: namely,
centralized, distributed and partially distributed power control using
Q-learning (CPC-Q, DPC-Q and PDPC-Q). CPCQ, although not of practical interest,
characterizes the global optimum. Each of DPC-Q and PDPC-Q works in two
different learning paradigms: Independent (IL) and Cooperative (CL). The former
is considered the simplest form for applying Qlearning in multi-agent
scenarios, where all the femtocells learn independently. The latter is the
proposed scheme in which femtocells share partial information during the
learning process in order to strike a balance between practical relevance and
performance. In terms of performance, the simulation results showed that the CL
paradigm outperforms the IL paradigm and achieves an aggregate femtocells
capacity that is very close to the optimal one. For the practical relevance
issue, we evaluate the robustness and scalability of DPC-Q, in real time, by
deploying new femtocells in the system during the learning process, where we
showed that DPC-Q in the CL paradigm is scalable to large number of femtocells
and more robust to the network dynamics compared to the IL paradigm


title:
Spectral properties of Schr\"odinger operators on compact manifolds:
  rigidity, flows, interpolation and spectral estimates

abstract:
  This note is devoted to optimal spectral estimates for Schr\"odinger
operators on compact connected Riemannian manifolds without boundary. These
estimates are based on the use of appropriate interpolation inequalities and on
some recent rigidity results for nonlinear elliptic equations on those
manifolds.


title: Stable sampling and Fourier multipliers

abstract:
  We study the relationship between stable sampling sequences for bandlimited
functions in $L^p(\R^n)$ and the Fourier multipliers in $L^p$. In the case that
the sequence is a lattice and the spectrum is a fundamental domain for the
lattice the connection is complete. In the case of irregular sequences there is
still a partial relationship.


title: Modeling Basic Aspects of Cyber-Physical Systems

abstract:
  Designing novel cyber-physical systems entails significant, costly physical
experimentation. Simulation tools can enable the virtualization of experiments.
Unfortunately, current tools have shortcomings that limit their utility for
virtual experimentation. Language research can be especially helpful in
addressing many of these problems. As a first step in this direction, we
consider the question of determining what language features are needed to model
cyber-physical systems. Using a series of elementary examples of cyber-physical
systems, we reflect on the extent to which a small, experimental
domain-specific formalism called Acumen suffices for this purpose.


title:
Explicit formula of energy-conserving, Fokker-Planck type collision term
  for nonaxisymmetric, single species point vortex system

abstract:
  This paper considers a kinetic equation for an unbounded two-dimensional
single species point vortex system. No axisymmetric flow is assumed. Using the
kinetic theory based on the Klimontovich formalism, we derive a collision term
consisting of a diffusion and a drift term, whose structure is similar to the
Fokker-Planck equation. The collision term exhibits several important
properties: (a) it includes a nonlocal effect; (b) it conserves the mean field
energy; (c) it satisfies the H theorem; (d) its effect vanishes in each local
equilibrium region with the same temperature. When the system reaches a global
equilibrium state, the collision term completely converge to zero all over the
system.


title:
Markov dynamics on the Thoma cone: a model of time-dependent
  determinantal processes with infinitely many particles

abstract:
  The Thoma cone is an infinite-dimensional locally compact space, which is
closely related to the space of extremal characters of the infinite symmetric
group. In another context, the Thoma cone appears as the set of parameters for
totally positive, upper triangular Toeplitz matrices of infinite size.
  The purpose of the paper is to construct a family of continuous time Markov
processes on the Thoma cone, depending on two continuous parameters. Our
construction largely exploits specific properties of the Thoma cone related to
its representation-theoretic origin, although we do not use representations
directly. On the other hand, we were inspired by analogies with random matrix
theory coming from models of Markov dynamics related to orthogonal polynomial
ensembles.
  We show that our processes possess a number of nice properties, namely: (1)
every process X is a Feller process; (2) the infinitesimal generator of X, its
spectrum, and the eigenfunctions admit an explicit description; (3) in the
equilibrium regime, the finite-dimensional distributions of X can be
interpreted as (the laws of) infinite-particle systems with determinantal
correlations; (4) the corresponding time-dependent correlation kernel admits an
explicit expression, and its structure is similar to that of time-dependent
correlation kernels appearing in random matrix theory.


title: An interacting particle process related to Young tableaux

abstract:
  We discuss a stochastic particle system consisting of a two-dimensional array
of particles living in one space dimension. The stochastic evolution bears a
certain similarity to Hammersley's process, and the particle interaction is
governed by combinatorics of the Young tableaux.


title: Damped jump-telegraph processes

abstract:
  We study a one-dimensional Markov modulated random walk with jumps. It is
assumed that amplitudes of jumps as well as a chosen velocity regime are random
and depend on a time spent by the process at a previous state of the underlying
Markov process.
  Equations for the distribution and equations for its moments are derived. We
characterise the martingale distributions in terms of observable proportions
between jump and velocity regimes.