title:
Spatial and temporal scales of force and torque acting on wall-mounted
  spherical particles in open channel flow

abstract:
  Data from direct numerical simulation of open channel flow over a
geometrically rough wall at a bulk Reynolds number of 2900, generated by
Chan-Braun et al. ["Force and torque acting on particles in a transitionally
rough open-channel flow", J. Fluid Mech. 684, 441--474 (2011),
10.1017/jfm.2011.311] are further analysed with respect to the time and length
scales of force and torque acting on the wall-mounted spheres. For the two
sizes of spheres in a square arrangement (11 and 49 wall units in diameter,
yielding hydraulically smooth and transitionally rough flow, respectively), the
spatial structure of drag, lift and spanwise torque is investigated. The
auto-correlation and spectra in time as well as the space-time correlation and
convection velocities are presented and discussed. It is found that the
statistics of spanwise particle torque are similar to those of shear stress at
a smooth wall. Particle drag and lift are shown to differ from spanwise
particle torque, exhibiting considerably smaller time and length scales; the
convection velocities of drag and lift are somewhat larger than those of
spanwise torque. Furthermore, correlations between the flow field and
particle-related quantities are presented. The spatial structure of the
correlation between streamwise velocity and drag/spanwise torque features
elongated shapes reminiscent of buffer-layer streaks. The correlation between
the pressure field and the particle drag exhibits two opposite-signed bulges on
the upstream and downstream sides of a particle.


title:
Influence of material defects on current-driven vortex domain wall
  mobility

abstract:
  Many future concepts for spintronic devices are based on the current-driven
motion of magnetic domain walls through nanowires. Consequently a thorough
understanding of the domain wall mobility is required. However, the magnitude
of the nonadiabatic component of the spin-transfer torque driving the domain
wall is still debated today as various experimental methods give rise to a
large range of values for the degree of nonadiabaticity. Strikingly,
experiments based on vortex domain wall motion in magnetic nanowires
consistently result in lower values compared to other methods. Based on the
micromagnetic simulations presented in this contribution we can attribute this
discrepancy to the influence of distributed disorder which vastly affects the
vortex domain wall mobility, but is most often not taken into account in the
models adopted to extract the degree of nonadiabaticity.


title:
Modified CRB for Location and Velocity Estimation using Signals of
  Opportunity

abstract:
  We consider the problem of localizing two sensors using signals of
opportunity from beacons with known positions. Beacons and sensors have
asynchronous local clocks or oscillators with unknown clock skews and offsets.
We model clock skews as random, and analyze the biases introduced by clock
asynchronism in the received signals. By deriving the equivalent Fisher
information matrix for the modified Bayesian Cram\'er-Rao lower bound (CRLB) of
sensor position and velocity estimation, we quantify the errors caused by clock
asynchronism.


title: Dynamic localization in Glauber-Fock lattices

abstract:
  Glauber-Fock lattices refer to a special class of semi-infinite tight-binding
lattices with inhomogeneous hopping rates which are found in certain simple
solid-state, quantum optics and quantum field theoretical models. Here it is
shown that dynamic localization, i.e. suppression of quantum diffusion and
periodic quantum self-imaging by an external sinusoidal force [D.H. Dunlap and
V.M. Kenkre, Phys. Rev. B {\bf 34}, 3625 (1986)], can be exactly realized in
Glauber-Fock lattices, in spite of inhomogeneity of hopping rates and lattice
truncation.


title: AGN outflows trigger starbursts in gas-rich galaxies

abstract:
  Recent well resolved numerical simulations of AGN feedback have shown that
its effects on the host galaxy may be not only negative but also positive. In
the late gas poor phase, AGN feedback blows the gas away and terminates star
formation. However, in the gas-rich phase(s), AGN outflows trigger star
formation by over-compressing cold dense gas and thus provide positive feedback
on their hosts. In this paper we study this AGN-triggered starburst effect. We
show that star formation rate in the burst increases until the star formation
feedback counteracts locally the AGN outflow compression. Globally, this
predicts a strong nearly linear statistical correlation between the AGN and
starburst bolometric luminosities in disc galaxies, L_* \propto L_{AGN}^{5/6}.
The correlation is statistical only because AGN activity may fluctuate on short
time scales (as short as tens of years), and because AGN may turn off but its
effects on the host may continue to last until the AGN-driven outflow leaves
the host, which may be up to 10 times longer than the duration of the AGN
activity. The coefficient in front of this relation depends on the clumpiness
and morphology of the cold gas in the galaxy. A "maximum starburst" takes place
in am azimuthally uniform gas disc, for which we derive an upper limit of L_*
\sim 50 times larger than L_{AGN} for typical quasars. For more clumpy and/or
compact cold gas distributions, the starburst luminosity decreases. We also
suggest that similar AGN-triggerred starbursts are possible in hosts of all
geometries, including during galaxy mergers, provided the AGN is activated.
Finally, we note that due to the short duration of the AGN activity phase the
accelerating influence of AGN on starbursts may be much more common than
observations of simultaneous AGN and starbursts would suggest.


title: Subdivision schemes, network flows and linear optimization

abstract:
  We link regularity and smoothness analysis of multivariate vector subdivision
schemes with network flow theory and with special linear optimization problems.
This connection allows us to prove the existence of what we call optimal
difference masks that posses crucial properties unifying the regularity
analysis of univariate and multivariate subdivision schemes. We also provide
efficient optimization algorithms for construction of such optimal masks.
Integrality of the corresponding optimal values leads to purely analytic proofs
of $C^k-$regularity of subdivision.


title: Online Learning under Delayed Feedback

abstract:
  Online learning with delayed feedback has received increasing attention
recently due to its several applications in distributed, web-based learning
problems. In this paper we provide a systematic study of the topic, and analyze
the effect of delay on the regret of online learning algorithms. Somewhat
surprisingly, it turns out that delay increases the regret in a multiplicative
way in adversarial problems, and in an additive way in stochastic problems. We
give meta-algorithms that transform, in a black-box fashion, algorithms
developed for the non-delayed case into ones that can handle the presence of
delays in the feedback loop. Modifications of the well-known UCB algorithm are
also developed for the bandit problem with delayed feedback, with the advantage
over the meta-algorithms that they can be implemented with lower complexity.


title:
Characterizing the Orbital and Dynamical State of the HD 82943 Planetary
  System With Keck Radial Velocity Data

abstract:
  We present an updated analysis of radial velocity data of the HD 82943
planetary system based on 10 years of measurements obtained with the Keck
telescope. Previous studies have shown that the HD 82943 system has two planets
that are likely in 2:1 mean-motion resonance (MMR), with the orbital periods
about 220 and 440 days (Lee et al. 2006). However, alternative fits that are
qualitatively different have also been suggested, with two planets in a 1:1
resonance (Gozdziewski & Konacki 2006) or three planets in a Laplace 4:2:1
resonance (Beauge et al. 2008). Here we use \c{hi}2 minimization combined with
parameter grid search to investigate the orbital parameters and dynamical
states of the qualitatively different types of fits, and we compare the results
to those obtained with the differential evolution Markov chain Monte Carlo
method. Our results support the coplanar 2:1 MMR configuration for the HD 82943
system, and show no evidence for either the 1:1 or 3-planet Laplace resonance
fits. The inclination of the system with respect to the sky plane is well
constrained at about 20(+4.9 -5.5) degree, and the system contains two planets
with masses of about 4.78 MJ and 4.80 MJ (where MJ is the mass of Jupiter) and
orbital periods of about 219 and 442 days for the inner and outer planet,
respectively. The best fit is dynamically stable with both eccentricity-type
resonant angles {\theta}1 and {\theta}2 librating around 0 degree.


title:
Recurrence Plots 25 years later -- gaining confidence in dynamical
  transitions

abstract:
  Recurrence plot based time series analysis is widely used to study changes
and transitions in the dynamics of a system or temporal deviations from its
overall dynamical regime. However, most studies do not discuss the significance
of the detected variations in the recurrence quantification measures. In this
letter we propose a novel method to add a confidence measure to the recurrence
quantification analysis. We show how this approach can be used to study
significant changes in dynamical systems due to a change in control parameters,
chaos-order as well as chaos-chaos transitions. Finally we study and discuss
climate transitions by analysing a marine proxy record for past sea surface
temperature. This paper is dedicated to the 25th anniversary of the
introduction of recurrence plots.


title: Resonant planetary dynamics: Periodic orbits and long-term stability

abstract:
  Many exo-solar systems discovered in the last decade consist of planets
orbiting in resonant configurations and consequently, their evolution should
show long-term stability. However, due to the mutual planetary interactions a
multi-planet system shows complicated dynamics with mostly chaotic
trajectories. We can determine possible stable configurations by computing
resonant periodic trajectories of the general planar three body problem, which
can be used for modeling a two-planet system. In this work, we review our model
for both the planar and the spatial case. We present families of symmetric
periodic trajectories in various resonances and study their linear horizontal
and vertical stability. We show that around stable periodic orbits there exist
regimes in phase space where regular evolution takes place. Unstable periodic
orbits are associated with the existence of chaos and planetary
destabilization.


title: Dynamical Steady-States in Driven Quantum Systems

abstract:
  We derive dynamical equations for a driven, dissipative quantum system in
which the environment- induced relaxation rate is comparable to the Rabi
frequency, avoiding assumptions on the frequency dependence of the
environmental coupling. When the environmental coupling varies significantly on
the scale of the Rabi frequency, secular or rotating wave approximations break
down. Our approach avoids these approximations, yielding dynamical, periodic
steady-states. This is important for the qualitative and quantitative
description of the interaction between driven quantum dots and their phonon
environment. The theory agrees well with recent experiments, describing the
transition from asymmetric unsaturated resonances at weak driving to population
inversion at strong driving.


title: Probabilistic View of Explosion in an Inelastic Kac Model

abstract:
  Let $\{\mu(\cdot,t):t\geq0\}$ be the family of probability measures
corresponding to the solution of the inelastic Kac model introduced in
Pulvirenti and Toscani [\textit{J. Stat. Phys.} \textbf{114} (2004) 1453-1480].
It has been proved by Gabetta and Regazzini [\textit{J. Statist. Phys.}
\textbf{147} (2012) 1007-1019] that the solution converges weakly to
equilibrium if and only if a suitable symmetrized form of the initial data
belongs to the standard domain of attraction of a specific stable law. In the
present paper it is shown that, for initial data which are heavier-tailed than
the aforementioned ones, the limiting distribution is improper in the sense
that it has probability 1/2 "adherent" to $-\infty$ and probability 1/2
"adherent" to $+\infty$. It is explained in which sense this phenomenon is
amenable to a sort of explosion, and the main result consists in an explicit
expression of the rate of such an explosion. The presentation of these
statements is preceded by a discussion about the necessity of the assumption
under which their validity is proved. This gives the chance to make an
adjustment to a portion of a proof contained in the above-mentioned paper by
Gabetta and Regazzini.


title: Quantum simulation of the Riemann-Hurwitz zeta function

abstract:
  We propose a simple realization of a quantum simulator of the Riemann-Hurwitz
(RH) \zeta\ function based on a truncation of its Dirichlet representation. We
synthesize a nearest-neighbour-interaction Hamiltonian, satisfying the property
that the temporal evolution of the autocorrelation function of an initial bare
state of the Hamiltonian reproduces the RH function along the line \sigma+i
\omega t of the complex plane, with \sigma>1. The tight-binding Hamiltonian
with engineered hopping rates and site energies can be implemented in a variety
of physical systems, including trapped ion systems and optical waveguide
arrays. The proposed method is scalable, which means that the simulation can be
in principle arbitrarily accurate. Practical limitations of the suggested
scheme, arising from a finite number of lattice sites N and from decoherence,
are briefly discussed.


title:
Poisson point processes: Large deviation inequalities for the convex
  distance

abstract:
  An analogue of Talagrand's convex distance for binomial and Poisson point
processes is defined. A corresponding large deviation inequality is proved.


title: Iterated Tabu Search Algorithm for Packing Unequal Circles in a Circle

abstract:
  This paper presents an Iterated Tabu Search algorithm (denoted by ITS-PUCC)
for solving the problem of Packing Unequal Circles in a Circle. The algorithm
exploits the continuous and combinatorial nature of the unequal circles packing
problem. It uses a continuous local optimization method to generate locally
optimal packings. Meanwhile, it builds a neighborhood structure on the set of
local minimum via two appropriate perturbation moves and integrates two
combinatorial optimization methods, Tabu Search and Iterated Local Search, to
systematically search for good local minima. Computational experiments on two
sets of widely-used test instances prove its effectiveness and efficiency. For
the first set of 46 instances coming from the famous circle packing contest and
the second set of 24 instances widely used in the literature, the algorithm is
able to discover respectively 14 and 16 better solutions than the previous
best-known records.


title: Exotic Heavy Quark Spectroscopy - Theory Interpretation vs Data

abstract:
  An overview over recent spectroscopy results in comparison with data is
given. We focus on the exotica Z_b(10610), Z_b(10650) and Y_b(10890) in the
bottom sector and discuss a possible connection to the exotica in the charm
sector, namely to the resonances Y_c(4260) and Z_c(3900). Furthermore, future
prospects for the determination of the nature of Y_b(10890) are outlined.


title:
The effects of frequency-dependent quasar variability on the celestial
  reference frame

abstract:
  We examine the relationship between source position stability and
astrophysical properties of radio-loud quasars making up the International
Celestial Reference Frame. Understanding this relationship is important for
improving quasar selection and analysis strategies, and therefore reference
frame stability. We construct light curves for 95 of the most frequently
observed ICRF2 quasars at both the 2.3 and 8.4 GHz geodetic VLBI observing
bands. Because the appearance of new quasar components corresponds to an
increase in quasar flux density, these light curves alert us to potential
changes in source structure before they appear in VLBI images. We test how
source position stability depends on three astrophysical parameters: (1) Flux
density variability at X-band; (2) Time lag between flares in S and X-bands;
(3) Spectral index rms, defined as the variability in the ratio between S and
X-band flux densities. We find that small time lags between S and X-band light
curves, and low spectral index variability, are good indicators of position
stability. On the other hand, there is no strong dependence of source position
stability on flux density variability in a single frequency band. These
findings can be understood by interpreting the time lag between S and X-band
light curves as a measure of the size of the source structure. Monitoring of
source flux density at multiple frequencies therefore appears to provide a
useful probe of quasar structure on scales important to geodesy. We show how
multi-frequency flux density monitoring may allow the dependence on frequency
of the relative core positions along the jet to be elucidated. Knowledge of the
position-frequency relation has important implications for current and future
geodetic VLBI programs, as well as the alignment between the radio and optical
celestial reference frames. (Abridged)


title:
Estimating coupling directions in the cardio-respiratory system using
  recurrence properties

abstract:
  The asymmetry of coupling between complex systems can be studied by
conditional probabilities of recurrence, which can be estimated by joint
recurrence plots. This approach is applied for the first time on experimental
data: time series of the human cardio-respiratory system in order to
investigate the couplings between heart rate, mean arterial blood pressure, and
respiration. We find that the respiratory system couples towards the heart rate
and the heart rate towards the mean arterial blood pressure. However, our
analysis could not detect a clear coupling direction between the mean arterial
blood pressure and respiration.


title: Non-Hermitian shortcut to adiabaticity

abstract:
  A non-Hermitian shortcut to adiabaticity is introduced. By adding an
imaginary term in the diagonal elements of the Hamiltonian of a two state
quantum system, we show how one can cancel the nonadiabatic losses and perform
an arbitrarily fast population transfer, without the need to increase the
coupling. We apply this technique to two popular level-crossing models: the
Landau-Zener model and the Allen-Eberly model.


title: Composite stimulated Raman adiabatic passage

abstract:
  We introduce a high-fidelity technique for coherent control of three-state
quantum systems, which combines two popular control tools --- stimulated Raman
adiabatic passage (STIRAP) and composite pulses. By using composite sequences
of pairs of partly delayed pulses with appropriate phases the nonadiabatic
transitions, which prevent STIRAP from reaching unit fidelity, can be canceled
to an arbitrary order by destructive interference, and therefore the technique
can be made arbitrarily accurate. The composite phases are given by simple
analytic formulas, and they are universal for they do not depend on the
specific pulse shapes, the pulse delay and the pulse areas.


title: Symmetry breaking in binary chain with nonlinear sites

abstract:
  We consider a system of two or four nonlinear sites coupled with binary chain
waveguides. When a monochromatic wave is injected into the first (symmetric)
propagation channel the presence of cubic nonlinearity can lead to symmetry
breaking giving rise to emission of antisymmetric wave into the second
(antisymmetric) propagation channel of the waveguides. We found that in the
case of nonlinear plaquette there is a domain in the parameter space where
neither symmetry preserving nor symmetry breaking stable stationary solutions
exit. As a result injection of a monochromatic symmetric wave gives rise to
emission of nonsymmetric satellite waves with energies different from the
energy of the incident wave. Thus, the response exhibits nonmonochromatic
behavior.


title: Populations in statistical genetic modelling and inference

abstract:
  What is a population? This review considers how a population may be defined
in terms of understanding the structure of the underlying genetics of the
individuals involved. The main approach is to consider statistically
identifiable groups of randomly mating individuals, which is well defined in
theory for any type of (sexual) organism. We discuss generative models using
drift, admixture and spatial structure, and the ancestral recombination graph.
These are contrasted with statistical models for inference, principle component
analysis and other `non-parametric' methods. The relationships between these
approaches are explored with both simulated and real-data examples. The
state-of-the-art practical software tools are discussed and contrasted. We
conclude that populations are a useful theoretical construct that can be well
defined in theory and often approximately exist in practice.


title:
Computational relativistic quantum dynamics and its application to
  relativistic tunneling and Kapitza-Dirac scattering

abstract:
  Computational methods are indispensable to study the quantum dynamics of
relativistic light-matter interactions in parameter regimes where analytical
methods become inapplicable. We present numerical methods for solving the
time-dependent Dirac equation and the time-dependent Klein-Gordon equation and
their implementation on high performance graphics cards. These methods allow us
to study tunneling from hydrogen-like highly charged ions in strong laser
fields and Kapitza-Dirac scattering in the relativistic regime.


title: Standard Model gauge couplings from gauge-dilatation symmetry breaking

abstract:
  We argue that there is a spontaneously broken rotational symmetry between
space-time coordinates and gauge theoretical phases. The dilatonic mode acts as
the massive Higgs boson, whose vacuum expectation value determines the gauge
couplings. This mechanism requires that the quadratic divergences, or tadpoles
of the three gauge-theory couplings, unify at a certain scale. We verify this
statement, and find that this occurs at \Lambda_u ~ 4x10^7 GeV. The tadpole
cancellation condition, together with the dilaton self-energy, fixes the value
of the unified tadpole coefficient to be 1/[4 ln(\Lambda_cut/\Lambda_u)]. The
observed values of the coupling constants at \Lambda_u then implies \Lambda_cut
~ 4x10^18 GeV, which is close to the value of the reduced Planck mass
MR_Pl=M_Pl/sqrt(8 pi)=2.4 x 10^18 GeV. In other words, by assuming a cutoff at
M_Pl or MR_Pl, we are able to obtain predictions for the gauge couplings which
agree with the true values to within a few percent. It turns out that this
symmetry breaking can only take place if mass is generated with the aid of some
other means such as electroweak symmetry breaking. Assuming dynamical symmetry
breaking originating at MR_Pl, we obtain M_chi ~ 10^9 GeV, which is not
unreasonable but somewhat higher than \Lambda_u. The cancellation of an anomaly
in the dilaton self-energy requires that the number of fermionic generations
equals three.


title: A review on solar wind modeling: kinetic and fluid aspects

abstract:
  We review the main advantages and limitations of the kinetic exospheric and
fluid models of the solar wind (SW). We discuss the hydrostatic model imagined
by Chapman, the first supersonic hydrodynamic models published by Parker and
the first generation subsonic kinetic model proposed by Chamberlain. It is
shown that a correct estimation of the electric field as in the second
generation kinetic exospheric models developed by Lemaire and Scherer, provides
a supersonic expansion of the corona, reconciling the hydrodynamic and the
kinetic approach. The third generation kinetic exospheric models considers
kappa velocity distribution function (VDF) instead of a Maxwellian at the
exobase and in addition they treat a non-monotonic variation of the electric
potential with the radial distance; the fourth generation exospheric models
include Coulomb collisions based on the Fokker--Planck collision term.
Multi-fluid models of the solar wind provide a coarse grained description and
reproduce with success the spatio-temporal variation of SW macroscopic
properties (density, bulk velocity). The main categories of multi-fluid SW
models are reviewed: the 5-moment, or Euler, models, originally proposed by
Parker to describe the supersonic SW expansion; the 8-moment and 16-moment
fluid models, the gyrotropic approach with improved collision terms as well as
the gyrotropic models based on observed VDFs. The outstanding problem of
collisions, including the long range Coulomb encounters, is also discussed,
both in the kinetic and multi-fluid context. Although for decades the two
approaches have been seen as opposed, in this paper we emphasize their
complementary. The review of the kinetic and fluid models of the solar wind
contributes also to a better evaluation of the open questions still existent in
SW modeling and suggests possible future developments.


title: Active inductor shunt peaking in high-speed VCSEL driver design

abstract:
  An all transistor active inductor shunt peaking structure has been used in a
prototype of 8-Gbps high-speed VCSEL driver which is designed for the optical
link in ATLAS liquid Argon calorimeter upgrade. The VCSEL driver is fabricated
in a commercial 0.25-um Silicon-on-Sapphire (SoS) CMOS process for radiation
tolerant purpose. The all transistor active inductor shunt peaking is used to
overcome the bandwidth limitation from the CMOS process. The peaking structure
has the same peaking effect as the passive one, but takes a small area, does
not need linear resistors and can overcome the process variation by adjust the
peaking strength via an external control. The design has been tapped out, and
the prototype has been proofed by the preliminary electrical test results and
bit error ratio test results. The driver achieves 8-Gbps data rate as simulated
with the peaking. We present the all transistor active inductor shunt peaking
structure, simulation and test results in this paper.


title:
Tracing cross-free polylines oriented by a N-symmetry direction field on
  triangulated surfaces

abstract:
  We propose an algorithm for tracing polylines on a triangle mesh such that:
they are aligned with a N-symmetry direction field, and two such polylines
cannot cross or merge. This property is fundamental for mesh segmentation and
is very difficult to enforce with numerical integration of vector fields. We
propose an alternative solution based on "stream-mesh", a new combinatorial
data structure that defines, for each point of a triangle edge, where the
corresponding polyline leaves the triangle. It makes it possible to trace
polylines by iteratively crossing triangles. Vector field singularities and
polyline/vertex crossing are characterized and consistently handled. The
polylines inherits the cross-free property of the stream-mesh, except inside
triangles where avoiding local overlaps would require higher order polycurves.


title:
On convergence of numerical algorithm of a class of the spatial
  segregation of reaction-diffusion system with two population densities

abstract:
  Recently, much interest has gained the numerical approximation of equations
of the Spatial Segregation of Reaction-diffusion systems with m population
densities. These problems are governed by a minimization problem subject to the
closed but non-convex set. In the present work we deal with the numerical
approximation of equations of stationary states for a certain class of the
Spatial Segregation of Reaction-diffusion system with two population densities
having disjoint support. We prove the convergence of the numerical algorithm
for two competing populations with non-negative internal dynamics $f_i(x)\geq
0.$ At the end of the paper we present computational tests.


title: Rank of tensors with size 2 x ... x 2

abstract:
  We study an upper bound of ranks of $n$-tensors with size
$2\times\cdots\times2$ over the complex and real number field. We characterize
a $2\times 2\times 2$ tensor with rank 3 by using the Cayley's hyperdeterminant
and some function. Then we see another proof of Brylinski's result that the
maximal rank of $2\times2\times2\times2$ complex tensors is 4. We state
supporting evidence of the claim that 5 is a typical rank of
$2\times2\times2\times2$ real tensors. Recall that Kong and Jiang show that the
maximal rank of $2\times2\times2\times2$ real tensors is less than or equal to
5. The maximal rank of $2\times2\times2\times2$ complex (resp. real) tensors
gives an upper bound of the maximal rank of $2\times\cdots\times 2$ complex
(resp. real) tensors.


title: Controlling active self-assembly through broken particle symmetries

abstract:
  Many structural properties of conventional passive materials are known to
arise from the symmetries of their microscopic constituents. By contrast, it is
largely unclear how the interplay between cell shape and self-propulsion
controls the meso- and macroscale behavior of active matter. Here, we analyze
large-scale simulations of homo- and heterogeneous self-propelled particle
systems to identify generic effects of broken particle symmetry on collective
motion. We find that even small violations of fore-aft symmetry lead to
fundamentally different collective behaviors, which may facilitate demixing of
differently shaped species as well as the spontaneous formation of stable
micro-rotors. These results suggest that variation of particle shape yields
robust physical mechanisms to control self-assembly of active matter, with
possibly profound implications for biology and materials design.


title:
On the Optimum Cyclic Subcode Chains of $\mathcal{RM}(2,m)^*$ for
  Increasing Message Length

abstract:
  The distance profiles of linear block codes can be employed to design
variational coding scheme for encoding message with variational length and
getting lower decoding error probability by large minimum Hamming distance. %,
e.g. the design of TFCI in CDMA and the researches on the second-order
Reed-Muller code $\mathcal{RM}(2,m)$, etc.
  Considering convenience for encoding, we focus on the distance profiles with
respect to cyclic subcode chains (DPCs) of cyclic codes over $GF(q)$ with
length $n$ such that $\mbox{gcd}(n,q) = 1$. In this paper the optimum DPCs and
the corresponding optimum cyclic subcode chains are investigated on the
punctured second-order Reed-Muller code $\mathcal{RM}(2,m)^*$ for increasing
message length, where two standards on the optimums are studied according to
the rhythm of increase.


title: Yangian symmetric correlators

abstract:
  Similarity transformations and eigenvalue relations of monodromy operators
composed of Jordan-Schwinger type L matrices are considered and used to define
Yangian symmetric correlators of n-dimensional theories. Explicit expressions
are obtained and relations are formulated. In this way basic notions of the
Quantum inverse scattering method provide a convenient formulation for high
symmetry and integrability not only in lower dimensions.


title:
Resource Allocation for Secure Communication in Systems with Wireless
  Information and Power Transfer

abstract:
  This paper considers secure communication in a multiuser multiple-input
single-output (MISO) downlink system with simultaneous wireless information and
power transfer. We study the design of resource allocation algorithms
minimizing the total transmit power for the case when the receivers are able to
harvest energy from the radio frequency. In particular, the algorithm design is
formulated as a non-convex optimization problem which takes into account
artificial noise generation to combat potential eavesdroppers, a minimum
required signal-to-interference-plus-noise ratio (SINR) at the desired
receiver, maximum tolerable SINRs at the potential eavesdroppers, and a minimum
required power delivered to the receivers. We adopt a semidefinite programming
(SDP) relaxation approach to obtain an upper bound solution for the considered
problem. The tightness of the upper bound is revealed by examining a sufficient
condition for the global optimal solution. Inspired by the sufficient
condition, we propose two suboptimal resource allocation schemes enhancing
secure communication and facilitating efficient energy harvesting. Simulation
results demonstrate a close-to-optimal performance achieved by the proposed
suboptimal schemes and significant transmit power savings by optimization of
the artificial noise generation.


title:
Effect of charge doping on the electronic structure, orbital
  polarization, and structural distortion in nickelate superlattice

abstract:
  Using first-principles density functional theory calculations, we
investigated the effect of charge doping in a LaNiO$_3$/SrTiO$_3$ superlattice.
The detailed analysis based on two different simulation methods for doping
clearly shows that the electronic and structural properties change in a
systematic way that the orbital polarization ({\it i.e.} relative occupation of
two Ni-$e_g$ orbitals) is reduced and the Ni to apical oxygen distance enlarged
as the number of doped electrons increases. Also, the rotation angles of the
NiO$_6$/TiO$_6$ octahedra strongly and systematically depend on the doping so
that the angle $\gamma$ gradually decreases whereas the $\alpha$ and $\beta$
increase as a function of electron doping. Further analysis shows that the
electron (hole) doping can play a similar role with the compressive (tensile)
strain for the octahedral rotations. Our results not only suggest a possible
way to control the orbital and structural property by means of charge doping,
but also provide useful information to understand the experiments under various
doping situations such as oxygen vacancy.


title:
Lp mean estimates for an operator preserving inequalities between
  polynomials

abstract:
  If $P(z)$ be a polynomial of degree at most $n$ which does not vanish in $|z|
< 1$, it was recently formulated by Shah and Liman \cite[\textit{Integral
estimates for the family of $B$-operators, Operators and Matrices,}
\textbf{5}(2011), 79 - 87]{wl} that for every $R\geq 1$, $p\geq 1$,
  \[\left\|B[P\circ\sigma](z)\right\|_p
\leq\frac{R^{n}|\Lambda_n|+|\lambda_{0}|}{\left\|1+z\right\|_p}\left\|P(z)\right\|_p,\]
where $B$ is a $ \mathcal{B}_{n}$-operator with parameters $\lambda_{0},
\lambda_{1}, \lambda_{2}$ in the sense of Rahman \cite{qir}, $\sigma(z)=Rz$ and
$\Lambda_n=\lambda_{0}+\lambda_{1}\frac{n^{2}}{2}
+\lambda_{2}\frac{n^{3}(n-1)}{8}$. Unfortunately the proof of this result is
not correct. In this paper, we present a more general sharp $L_p$-inequalities
for $\mathcal{B}_{n}$-operators which not only provide a correct proof of the
above inequality as a special case but also extend them for $ 0 \leq p <1$ as
well.


title: Random Walks on Stochastic Temporal Networks

abstract:
  In the study of dynamical processes on networks, there has been intense focus
on network structure -- i.e., the arrangement of edges and their associated
weights -- but the effects of the temporal patterns of edges remains poorly
understood. In this chapter, we develop a mathematical framework for random
walks on temporal networks using an approach that provides a compromise between
abstract but unrealistic models and data-driven but non-mathematical
approaches. To do this, we introduce a stochastic model for temporal networks
in which we summarize the temporal and structural organization of a system
using a matrix of waiting-time distributions. We show that random walks on
stochastic temporal networks can be described exactly by an
integro-differential master equation and derive an analytical expression for
its asymptotic steady state. We also discuss how our work might be useful to
help build centrality measures for temporal networks.


title:
Lieb-Robinson bounds and the simulation of time evolution of local
  observables in lattice systems

abstract:
  This is an introductory text reviewing Lieb-Robinson bounds for open and
closed quantum many-body systems. We introduce the Heisenberg picture for
time-dependent local Liouvillians and state a Lieb-Robinson bound that gives
rise to a maximum speed of propagation of correlations in many body systems of
locally interacting spins and fermions. Finally, we discuss a number of
important consequences concerning the simulation of time evolution and
properties of ground states and stationary states.

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


title:
Imaginary eigenvalues and complex eigenvectors explained by real
  geometry

abstract:
  This paper first reviews how anti-symmetric matrices in two dimensions yield
imaginary eigenvalues and complex eigenvectors. It is shown how this carries on
to rotations by means of the Cayley transformation. Then a real geometric
interpretation is given to the eigenvalues and eigenvectors by means of real
geometric algebra. The eigenvectors are seen to be \textit{two component
eigenspinors} which can be further reduced to underlying vector duplets. The
eigenvalues are interpreted as rotation operators, which rotate the underlying
vector duplets. The second part of this paper extends and generalizes the
treatment to three dimensions. Finally the four-dimensional problem is stated.


title:
Constrained WZWN Models on G/{S x U(1)^n} and Exchange Algebra of
  G-Primaries

abstract:
  Consistently constrained WZWN models on G/{S x U(1)^n} is given by
constraining currents of the WZWN models with G. Poisson brackets are set up on
the light-like plane. Using them we show the Virasoro algebra for the
energy-momentum tensor of constrained WZWN models. We find a G-primary which
satisfies a classical exchange algebra in an arbitrary representation of G. The
G-primary and the constrained currents are also shown to obey the conformal
transformation with respect to the energy-momentum tensor. It is checked that
conformal weight of the constrained currents is 0. This is necessary for the
consistency for our formulation of constrained WZWN models.


title: Identification of a reversible quantum gate: assessing the resources

abstract:
  We assess the resources needed to identify a reversible quantum gate among a
finite set of alternatives, including in our analysis both deterministic and
probabilistic strategies. Among the probabilistic strategies we consider
unambiguous gate discrimination, where errors are not tolerated but
inconclusive outcomes are allowed, and we prove that parallel strategies are
sufficient to unambiguously identify the unknown gate with minimum number of
queries. This result is used to provide upper and lower bounds on the query
complexity and on the minimum ancilla dimension. In addition, we introduce the
notion of generalized t-designs, which includes unitary t-designs and group
representations as special cases. For gates forming a generalized t-design we
give an explicit expression for the maximum probability of correct gate
identification and we prove that there is no gap between the performances of
deterministic strategies an those of probabilistic strategies. Hence,
evaluating of the query complexity of perfect deterministic discrimination is
reduced to the easier problem of evaluating the query complexity of unambiguous
discrimination. Finally, we consider discrimination strategies where the use of
ancillas is forbidden, providing upper bounds on the number of additional
queries needed to make up for the lack of entanglement with the ancillas.


title: Maximal contractive tuples

abstract:
  Maximality of a contractive tuple of operators is considered.
Characterization of a contractive tuple to be maximal is obtained. Notion of
maximality of a submodule of Drury-Arveson module on the $d$-dimensional unit
ball $\mathbb{B}_d$ is defined. For $d=1$, it is shown that every submodule of
the Hardy module over the unit disc is maximal. But for $d\ge 2$ we prove that
any homogeneous submodule or submodule generated by polynomials is not maximal.
A characterization of a submodule to be maximal is obtained.


title:
Improving the accuracy and efficiency of time-resolved electronic
  spectra calculations: Cellular dephasing representation with a prefactor

abstract:
  Time-resolved electronic spectra can be obtained as the Fourier transform of
a special type of time correlation function known as fidelity amplitude, which,
in turn, can be evaluated approximately and efficiently with the dephasing
representation. Here we improve both the accuracy of this approximation---with
an amplitude correction derived from the phase-space propagator---and its
efficiency---with an improved cellular scheme employing inverse Weierstrass
transform and optimal scaling of the cell size. We demonstrate the advantages
of the new methodology by computing dispersed time-resolved stimulated emission
spectra in the harmonic potential, pyrazine, and the NCO molecule. In contrast,
we show that in strongly chaotic systems such as the quartic oscillator the
original dephasing representation is more appropriate than either the cellular
or prefactor-corrected methods.


title: The relativistic virial theorem and scale invariance

abstract:
  The virial theorem is related to the dilatation properties of bound states.
This is realized, in particular, by the Landau-Lifshitz formulation of the
relativistic virial theorem, in terms of the trace of the energy-momentum
tensor. We construct a Hamiltonian formulation of dilatations in which the
relativistic virial theorem naturally arises as the condition of stability
against dilatations. A bound state becomes scale invariant in the
ultrarelativistic limit, in which its energy vanishes. However, for very
relativistic bound states, scale invariance is broken by quantum effects and
the virial theorem must include the energy-momentum tensor trace anomaly. This
quantum field theory virial theorem is directly related to the Callan-Symanzik
equations. The virial theorem is applied to QED and then to QCD, focusing on
the bag model of hadrons. In massless QCD, according to the virial theorem, 3/4
of a hadron mass corresponds to quarks and gluons and 1/4 to the trace anomaly.


title: Gravity effects on thick brane formation from scalar field dynamics

abstract:
  The formation of a thick brane in five-dimen\-sional space-time is
investigated when warp geometries of $AdS_5$ type are induced by scalar matter
dynamics and triggered by a thin-brane defect. The scalar matter is taken to
consist of two fields with $O(2)$ symmetric self interaction and with manifest
$O(2)$ symmetry breaking by terms quadratic in fields. One of them serves as a
thick brane formation mode around a kink background and another one is of a
Higgs-field type which may develop a classical background as well. Scalar
matter interacts with gravity in the minimal form and gravity effects on
(quasi)localized scalar fluctuations are calculated with usage of gauge
invariant variables suitable for perturbation expansion. The calculations are
performed in the vicinity of the critical point of spontaneous breaking of the
combined parity symmetry where a non-trivial v.e.v. of the Higgs-type scalar
field is generated. The nonperturbative discontinuous gravitational effects in
the mass spectrum of light localized scalar states are studied in the presence
of a thin-brane defect. The thin brane with negative tension happens to be the
most curious case when the singular barriers form a potential well with two
infinitely tall walls and the discrete spectrum of localized states arises
completely isolated from the bulk.


title:
Wandering subspaces of the Bergman space and the Dirichlet space over
  polydisc

abstract:
  Doubly commutativity of invariant subspaces of the Bergman space and the
Dirichlet space over the unit polydisc $\mathbb{D}^n$ (with $ n \geq 2$) is
investigated. We show that for any non-empty subset
$\alpha=\{\alpha_1,\dots,\alpha_k\}$ of $\{1,\dots,n\}$ and doubly commuting
invariant subspace $\s$ of the Bergman space or the Dirichlet space over
$\D^n$, the tuple consists of restrictions of co-ordinate multiplication
operators $M_{\alpha}|_\s:=(M_{z_{\alpha_1}}|_\s,\dots, M_{z_{\alpha_k}}|_\s)$
always possesses wandering subspace of the form \[\bigcap_{i=1}^k(\s\ominus
z_{\alpha_i}\s). \]


title: Algebraic quotient modules and subgroup depth

abstract:
  In arXiv:1210.3178 it was shown that subgroup depth may be computed from the
permutation module of the left or right cosets: this holds more generally for a
Hopf subalgebra, from which we note in this paper that finite depth of a Hopf
subalgebra R < H is equivalent to the H-module coalgebra Q = H/R^+H
representing an algebraic element in the Green ring of H or R. This approach
shows that subgroup depth and the subgroup depth of the corefree quotient lie
in the same closed interval of length one. We also establish a previous claim
that the problem of determining if R has finite depth in H is equivalent to
determining if H has finite depth in its cross product Q* # H. A necessary
condition is obtained for finite depth from stabilization of a descending chain
of annihilator ideals of tensor powers of Q. As an application of these topics
to a centerless finite group G, we prove that the minimum depth of its group
complex algebra in the Drinfeld double D(G) is an odd integer, which determines
the least tensor power of the adjoint representation Q that is a faithful
complex G-module.


title:
Inter-grain tunneling in the half-metallic double-perovskites
  Sr$_2$BB'O$_6$ (BB'-- FeMo, FeRe, CrMo, CrW, CrRe

abstract:
  The zero-field conductivities ($\sigma$) of the polycrystaline title
materials, are governed by inter-grain transport. In the majority of cases
their $\sigma$(T) can be described by the "fluctuation induced tunneling"
model. Analysis of the results in terms of this model reveals two remarkable
features: 1. For \emph{all} Sr$_2$FeMoO$_6$ samples of various microstructures,
the tunneling constant (barrier width $\times$ inverse decay-length of the
wave-function) is $\sim$ 2, indicating the existence of an intrinsic insulating
boundary layer with a well defined electronic (and magnetic) structure. 2. The
tunneling constant for \emph{all} cold-pressed samples decreases linearly with
increasing magnetic-moment/formula-unit.


title:
Does it Matter Which Citation Tool is Used to Compare the h-index of a
  Group of Highly Cited Researchers?

abstract:
  h-index retrieved by citation indexes (Scopus, Google scholar, and Web of
Science) is used to measure the scientific performance and the research impact
studies based on the number of publications and citations of a scientist. It
also is easily available and may be used for performance measures of
scientists, and for recruitment decisions. The aim of this study is to
investigate the difference between the outputs and results from these three
citation databases namely Scopus, Google Scholar, and Web of Science based upon
the h-index of a group of highly cited researchers (Nobel Prize winner
scientist). The purposive sampling method was adopted to collect the required
data. The results showed that there is a significant difference in the h-index
between three citation indexes of Scopus, Google scholar, and Web of Science;
the Google scholar h-index was more than the h-index in two other databases. It
was also concluded that there is a significant positive relationship between
h-indices based on Google scholar and Scopus. The citation indexes of Scopus,
Google scholar, and Web of Science may be useful for evaluating h-index of
scientists but they have some limitations as well.


title:
Exponentially small asymptotic estimates for the splitting of
  separatrices to whiskered tori with quadratic and cubic frequencies

abstract:
  We study the splitting of invariant manifolds of whiskered tori with two or
three frequencies in nearly-integrable Hamiltonian systems. We consider
2-dimensional tori with a frequency vector $\omega=(1,\Omega)$ where $\Omega$
is a quadratic irrational number, or 3-dimensional tori with a frequency vector
$\omega=(1,\Omega,\Omega^2)$ where $\Omega$ is a cubic irrational number.
Applying the Poincare-Melnikov method, we find exponentially small asymptotic
estimates for the maximal splitting distance between the stable and unstable
manifolds associated to the invariant torus, showing that such estimates depend
strongly on the arithmetic properties of the frequencies. Inthe quadratic case,
we use the continued fractions theory to establish a certain arithmetic
property, fulfilled in 24 cases, which allows us to provide asymptotic
estimates in a simple way. In the cubic case, we focus our attention to the
case in which $\Omega$ is the so-called cubic golden number (the real root of
$x^3+x-1=0$), obtaining also asymptotic estimates. We point out the similitudes
and differences between the results obtained for both the quadratic and cubic
cases.


title: On Primitivity of Sets of Matrices

abstract:
  A nonnegative matrix $A$ is called primitive if $A^k$ is positive for some
integer $k>0$. A generalization of this concept to finite sets of matrices is
as follows: a set of matrices $\mathcal M = \{A_1, A_2, \ldots, A_m \}$ is
primitive if $A_{i_1} A_{i_2} \ldots A_{i_k}$ is positive for some indices
$i_1, i_2, ..., i_k$. The concept of primitive sets of matrices comes up in a
number of problems within the study of discrete-time switched systems. In this
paper, we analyze the computational complexity of deciding if a given set of
matrices is primitive and we derive bounds on the length of the shortest
positive product.
  We show that while primitivity is algorithmically decidable, unless $P=NP$ it
is not possible to decide primitivity of a matrix set in polynomial time.
Moreover, we show that the length of the shortest positive sequence can be
superpolynomial in the dimension of the matrices. On the other hand, defining
${\mathcal P}$ to be the set of matrices with no zero rows or columns, we give
a simple combinatorial proof of a previously-known characterization of
primitivity for matrices in ${\mathcal P}$ which can be tested in polynomial
time. This latter observation is related to the well-known 1964 conjecture of
Cerny on synchronizing automata; in fact, any bound on the minimal length of a
synchronizing word for synchronizing automata immediately translates into a
bound on the length of the shortest positive product of a primitive set of
matrices in ${\mathcal P}$. In particular, any primitive set of $n \times n$
matrices in ${\mathcal P}$ has a positive product of length $O(n^3)$.


title: Hermite-Hadamard type inequality for operator preinvex functions

abstract:
  In this paper we establish a Hermite- Hadamard type inequality for operator
preinvex functions and an estimate of the right hand side of a Hermite-
Hadamard type inequality in which some operator preinvex functions of
selfadjoint operators in Hilbert spaces are involved.


title: Electromagnetic properties of doubly charmed baryons in Lattice QCD

abstract:
  We compute the electromagnetic properties of \Xi_cc baryons in 2+1 flavor
Lattice QCD. By measuring the electric charge and magnetic form factors of
\Xi_cc baryons, we extract the magnetic moments, charge and magnetic radii as
well as the \Xi_cc \Xi_cc \rho coupling constant, which provide important
information to understand the size, shape and couplings of the doubly charmed
baryons. We find that the two heavy charm quarks drive the charge radii and the
magnetic moment of \Xi_cc to smaller values as compared to those of, e.g., the
proton.


title: On integrability of D0-brane equations on AdS_4 x CP^3 superbackground

abstract:
  Equations of motion for the D0-brane on AdS_4 x CP^3 superbackground are
shown to be classically integrable by extending the argument previously
elaborated for the massless superparticle model.


title:
Fast Gradient-Based Inference with Continuous Latent Variable Models in
  Auxiliary Form

abstract:
  We propose a technique for increasing the efficiency of gradient-based
inference and learning in Bayesian networks with multiple layers of continuous
latent vari- ables. We show that, in many cases, it is possible to express such
models in an auxiliary form, where continuous latent variables are
conditionally deterministic given their parents and a set of independent
auxiliary variables. Variables of mod- els in this auxiliary form have much
larger Markov blankets, leading to significant speedups in gradient-based
inference, e.g. rapid mixing Hybrid Monte Carlo and efficient gradient-based
optimization. The relative efficiency is confirmed in ex- periments.


title: The far emission region of the gamma-ray blazar PKS B1424-418

abstract:
  We report multi-wavelength (IR-O, UV, X-ray, gamma-ray) data of the flat
spectrum radio quasar (FSRQ) PKS B1424-418 (z=1.52) gathered during an active
phase in 2013 April . As for a few other cases of FSRQs reported in literature,
the detection by the Large Area Telescope onboard Fermi of gamma rays with
energy above 10 GeV indicates that the emission likely occurs beyond the highly
opaque (tau ~10) broad line region. This conclusion is strengthened by a model
fit to the spectral energy distribution, which allows us to locate the emission
region even beyond the distance generally assumed for the dusty torus. The
consequent large size (~1 pc) inferred for the emission region cannot account
for the observed daily-scale variability of the gamma-ray flux. We discuss the
possibility that short-term variability results from fast magnetic reconnection
events, as proposed in recent works.


title:
Particle approximations of the score and observed information matrix for
  parameter estimation in state space models with linear computational cost

abstract:
  Poyiadjis et al. (2011) show how particle methods can be used to estimate
both the score and the observed information matrix for state space models.
These methods either suffer from a computational cost that is quadratic in the
number of particles, or produce estimates whose variance increases
quadratically with the amount of data. This paper introduces an alternative
approach for estimating these terms at a computational cost that is linear in
the number of particles. The method is derived using a combination of kernel
density estimation, to avoid the particle degeneracy that causes the
quadratically increasing variance, and Rao-Blackwellisation. Crucially, we show
the method is robust to the choice of bandwidth within the kernel density
estimation, as it has good asymptotic properties regardless of this choice. Our
estimates of the score and observed information matrix can be used within both
online and batch procedures for estimating parameters for state space models.
Empirical results show improved parameter estimates compared to existing
methods at a significantly reduced computational cost. Supplementary materials
including code are available.


title: Irreducibility of generalized Hermite-Laguerre Polynomials III

abstract:
  For a positive integer $n$ and a real number $\alpha$, the generalized
Laguerre polynomials are defined by \begin{align*}
L^{(\alpha)}_n(x)=\sum^n_{j=0}\frac{(n+\alpha)(n-1+\alpha)\cdots
(j+1+\alpha)(-x)^j}{j!(n-j)!}. \end{align*} These orthogonal polynomials are
solutions to Laguerre's Differential Equation which arises in the treatment of
the harmonic oscillator in quantum mechanics. Schur studied these Laguerre
polynomials for its interesting algebraic properties. He obtained
irreducibility results of $L^{(\pm \frac{1}{2})}_n(x)$ and $L^{(\pm
\frac{1}{2})}_n(x^2)$ and derived that the Hermite polynomials $H_{2n}(x)$ and
$\frac{H_{2n+1}(x)}{x}$ are irreducible for each $n$. In this article, we
extend Schur's result by showing that the family of Laguerre polynomials
$L^{(q)}_n(x)$ and $L^{(q)}_n(x^d)$ with $q\in \{\pm \frac{1}{3}, \pm
\frac{2}{3}, \pm \frac{1}{4}, \pm \frac{3}{4}\}$, where $d$ is the denominator
of $q$, are irreducible for every $n$ except when $q=\frac{1}{4}, n=2$ where we
give the complete factorization. In fact, we derive it from a more general
result.


title: First Results of the PixelGEM Central Tracking System for COMPASS

abstract:
  For its physics program with a high-intensity hadron beam of up to 2e7
particles/s, the COMPASS experiment at CERN requires tracking of charged
particles scattered by very small angles with respect to the incident beam
direction. While good resolution in time and space is mandatory, the challenge
is imposed by the high beam intensity, requiring radiation-hard detectors which
add very little material to the beam path in order to minimize secondary
interactions.
  To this end, a set of triple-GEM detectors with a hybrid readout structure
consisting of pixels in the beam region and 2-D strips in the periphery was
designed and built. Successful prototype tests proved the performance of this
new detector type, showing both extraordinary high rate capability and
detection efficiency. The amplitude information allowed to achieve spatial
resolutions about a factor of 10 smaller than the pitch and a time resolution
close to the theoretical limit imposed by the layout.
  The PixelGEM central tracking system consisting of five detectors, slightly
improved with respect to the prototype, was completely installed in the COMPASS
spectrometer in spring 2008.


title:
Pulse broadening analysis for several new pulsars and anomalous
  scattering

abstract:
  We show the results of our analysis of the pulse broadening phenomenon in 25
pulsars at several frequencies using the data gathered with GMRT and Effelsberg
radiotelescopes. Twenty two of these pulsars were not studied in that regard
before and our work has increased the total number of pulsars with
multi-frequency scattering measurements to almost 50, basically doubling the
amount available so far. The majority of the pulsars we observed have high to
very-high dispersion measures (DM>200) and our results confirm the suggestion
of Loehmer et al.(2001, 2004) that the scatter time spectral indices for
high-DM pulsars deviate from the value predicted by a single thin screen model
with Kolmogorov's distribution of the density fluctuations. In this paper we
discuss the possible explanations for such deviations.


title: Effect of stellar spots on high-precision transit light-curve

abstract:
  Stellar activity features such as spots can create complications in
determining planetary parameters through spectroscopic and photometric
observations. The overlap of a transiting planet and a stellar spot, for
instance, can produce anomalies in the transit light curves that may lead to
inaccurate estimation of the transit duration, depth and timing. For instance
such inaccuracies can affect the precise derivation of the planet's radius. In
this paper, we present the results of a quantitative study on the effects of
stellar spots on high precision transit light curves. We show that spot
anomalies can lead to the estimate of a planet radius that is 4% smaller than
the real value. The effects on the transit duration can also be of the order of
4%, longer or shorter. Depending on the size and distribution of spots,
anomalies can also produce transit timing variations with significant
amplitudes. For instance, TTVs with signal amplitudes of 200 seconds can be
produced when the spot is completely dark and as large as the largest Sun spot.
Our study also indicates that the minimum size of a stellar spot with
detectable affects on the high precision transit light curve is around 0.03
time the stellar radius for typical Kepler telescope precision. We also show
that the strategy of including more free parameters (such as transit depth and
duration) in the fitting procedure to measure the transit time of each
individual transit will not produce accurate results in the case of active
stars.


title: Irreducibility of generalized Hermite-Laguerre Polynomials II

abstract:
  In this paper, we show that for each $n\geq 1$, the generalised
Hermite-Laguerre Polynomials $G_{\frac{1}{4}}$ and $G_{\frac{3}{4}}$ are either
irreducible or linear polynomial times an irreducible polynomial of degree
$n-1$.


title:
Hennessy-Milner Logic with Greatest Fixed Points as a Complete
  Behavioural Specification Theory

abstract:
  There are two fundamentally different approaches to specifying and verifying
properties of systems. The logical approach makes use of specifications given
as formulae of temporal or modal logics and relies on efficient model checking
algorithms; the behavioural approach exploits various equivalence or refinement
checking methods, provided the specifications are given in the same formalism
as implementations.
  In this paper we provide translations between the logical formalism of
Hennessy-Milner logic with greatest fixed points and the behavioural formalism
of disjunctive modal transition systems. We also introduce a new operation of
quotient for the above equivalent formalisms, which is adjoint to structural
composition and allows synthesis of missing specifications from partial
implementations. This is a substantial generalisation of the quotient for
deterministic modal transition systems defined in earlier papers.


title: Locally maximally entangleable states and W-type states

abstract:
  We investigate the relationship between locally maximally entangleable (LME)
states and W-type states which are equivalent to a W state under stochastic
local operations and classical communication (SLOCC). We prove that (i) some
special W-type states of three qubits are LME; and (ii) no W-type state of four
and more qubits is LME. Our results show that the W state of four and more
qubits cannot be prepared by using LME states under SLOCC. However, for three
qubits some special LME states can be used to prepare the W state under SLOCC.


title: AC vs. DC Electrophoretic Deposition of Hydroxyapatite on Titanium

abstract:
  The bio-inertness of titanium and its alloys attracts their use as bone
implants. However a bioactive coating is usually necessary for improving the
bone bonding of such implants. In this study, electrophoretic deposition(EPD)
of hydroxyapatite (HA) powder on titanium plate was performed using butanol as
solvent under direct current (DC) and alternating current (AC) fields. The zeta
potential of the suspensions was measured to understand their stability and the
charge on the particles. Coating thickness was varied by adjusting the voltage
and time of deposition. Surface morphology and cross section thickness were
studied using scanning electron microscopy and image analysis software. Surface
crack density was calculated from the micrographs. The results showed that the
samples of similar thickness have higher grain density when coated using AC as
compared to DC EPD. This facile but novel test proves the capability of AC-EPD
to attain denser and uniform HA coatings from non-aqueous medium.


title: BRST symmetry and $W$-algebra in higher derivative models

abstract:
  In this paper we discuss the (anti-)BRST symmetries and $W$-algebra of higher
derivative theories of relativistic particles satisfying general gauge
conditions. Using this formalism, the connection between the (anti-)BRST
symmetries and $W$-algebra for the rigid relativistic particle is established.
Incidentally, the full $W$-algebra emerges only when the anti-BRST
transformations are considered in tandem with the BRST ones. Further, the BRST
symmetry is made finite and coordinate-dependent. We show that such finite
coordinate-dependent BRST symmetry changes the BRST invariant gauge-fixing
fermion within the functional integration. This is exploited to connect two
different arbitrary gauge conditions.


title: Irreducibility of generalized Hermite-Laguerre polynomials

abstract:
  For a rational $q=u+\frac{\alpha}{d}$ with $u, \alpha, d\in \ACOBZ$ with
$u\ge 0, 1\le \alpha<d$, $\gcd(\alpha, d)=1$, the \emph{generalized
Hermite-Laguerre polynomials $G_q(x)$} are defined by \begin{align*}
G_q(x)&=a_nx^n+a_{n-1}(\alpha +(n-1+u)d)x^{n-1}+\cdots\\
&\quad+a_1\left(\prod^{n-1}_{i=1}(\alpha +(i+u)d)\right)x+a_0
\left(\prod^{n-1}_{i=0}(\alpha +(i+u)d)\right) \end{align*} where $a_0, a_1,
\cdots, a_n$ are arbitrary integers. We prove some irreducibility results of
$G_q(x)$ when $q\in \{\frac{1}{3}, \frac{2}{3}\}$ and extend some of the
earlier irreducibility results when $q$ of the form $u+\frac{1}{2}$. We also
prove a new improved lower bound for greatest prime factor of product of
consecutive terms of an arithmetic progression whose common difference is 2 and
3.


title: Schwarzenberger bundles on smooth projective varieties

abstract:
  We define Schwarzenberger bundles on any smooth projective variety X. We
introduce the notions of jumping pairs of a Steiner bundle E on X and determine
a bound for the dimension of its jumping locus. We completely classify Steiner
bundles whose set of jumping pairs have maximal dimension, proving that they
are all Schwarzenberger bundles.


title: On the number of conjugacy classes of $\pi$-elements in finite groups

abstract:
  Let $G$ be a finite group and $\pi$ be a set of primes. We show that if the
number of conjugacy classes of $\pi$-elements in $G$ is larger than $5/8$ times
the $\pi$-part of $|G|$ then $G$ possesses an abelian Hall $\pi$-subgroup which
meets every conjugacy class of $\pi$-elements in $G$. This extends and
generalizes a result of W. H. Gustafson.


title: Large time behavior for some nonlinear degenerate parabolic equations

abstract:
  We study the asymptotic behavior of Lipschitz continuous solutions of
nonlinear degenerate parabolic equations in the periodic setting. Our results
apply to a large class of Hamilton-Jacobi-Bellman equations. Defining S as the
set where the diffusion vanishes, i.e., where the equation is totally
degenerate, we obtain the convergence when the equation is uniformly parabolic
outside S and, on S, the Hamiltonian is either strictly convex or satisfies an
assumption similar of the one introduced by Barles-Souganidis (2000) for
first-order Hamilton-Jacobi equations. This latter assumption allows to deal
with equations with nonconvex Hamiltonians. We can also release the uniform
parabolic requirement outside S. As a consequence, we prove the convergence of
some everywhere degenerate second-order equations.


title:
Molecular dynamics simulations of single-component bottle-brush polymers
  with a flexible backbone under poor solvent conditions

abstract:
  Conformations of a single-component bottle-brush polymer with a fully
flexible backbone under poor solvent conditions are studied by
molecular-dynamics simulations, using a coarse-grained bead-spring model with
side chains of up to N=40 effective monomers. By variation of the solvent
quality and the grafting density $\sigma$ with which side chains are grafted
onto the flexible backbone, we study for backbone lengths of up to $N_b=100$
the crossover from the brush/coil regime to the dense collapsed state. At lower
temperatures, where collapsed chains with a constant monomer density are
observed, the choice of the above parameters does not play any role and it is
the total number of monomers that defines the dimensions of the chains.
Furthermore, bottle-brush polymers with longer side chains possess higher
spherical symmetry compared to chains with lower side-chain lengths in contrast
to what one may intuitively expect, as the stretching of the side chains is
less important than the increase of their length. At higher temperatures,
always below the Theta ($\Theta$) temperature, coil-like configurations,
similar to a single polymer chain, or brush-like configurations, similar to a
homogeneous cylindrical bottle-brush polymer with a rigid backbone, are
observed, depending on the choice of the particular parameters $N$ and
$\sigma$. In the crossover regime between the collapsed state (globule) and the
coil/brush regime the acylindricity increases, whereas for temperatures outside
of this range, bottle-brush polymers maintain a highly cylindrical symmetry in
all configurational states.


title:
Evaluating Wireless Proactive Routing Protocols under Mobility and
  Scalability Constraints

abstract:
  Wireless Multi-hop Networks (WMhNs) provide users with the facility to
communicate while moving with whatever the node speed, the node density and the
number of traffic flows they want, without any unwanted delay and/or
disruption. This paper contributes Linear Programming models (LP_models) for
WMhNs. In WMhNs, different routing protocols are used to facilitate users
demand(s). To practically examine the constraints of respective LP_models over
different routing techniques, we select three proactive routing protocols;
Destination Sequence Distance Vector (DSDV), Fish-eye State Routing (FSR) and
Optimized Link State Routing (OLSR). These protocols are simulated in two
important scenarios regarding to user demands; mobilities and different network
flows. To evaluate the performance, we further relate the protocols strategy
effects on respective constraints in selected network scenarios.


title: First-Order Decomposition Trees

abstract:
  Lifting attempts to speed up probabilistic inference by exploiting symmetries
in the model. Exact lifted inference methods, like their propositional
counterparts, work by recursively decomposing the model and the problem. In the
propositional case, there exist formal structures, such as decomposition trees
(dtrees), that represent such a decomposition and allow us to determine the
complexity of inference a priori. However, there is currently no equivalent
structure nor analogous complexity results for lifted inference. In this paper,
we introduce FO-dtrees, which upgrade propositional dtrees to the first-order
level. We show how these trees can characterize a lifted inference solution for
a probabilistic logical model (in terms of a sequence of lifted operations),
and make a theoretical analysis of the complexity of lifted inference in terms
of the novel notion of lifted width for the tree.


title: Near-colorings: non-colorable graphs and NP-completeness

abstract:
  A graph G is (d_1,..,d_l)-colorable if the vertex set of G can be partitioned
into subsets V_1,..,V_l such that the graph G[V_i] induced by the vertices of
V_i has maximum degree at most d_i for all 1 <= i <= l. In this paper, we focus
on complexity aspects of such colorings when l=2,3. More precisely, we prove
that, for any fixed integers k,j,g with (k,j) distinct form (0,0) and g >= 3,
either every planar graph with girth at least g is (k,j)-colorable or it is
NP-complete to determine whether a planar graph with girth at least g is
(k,j)-colorable. Also, for any fixed integer k, it is NP-complete to determine
whether a planar graph that is either (0,0,0)-colorable or
non-(k,k,1)-colorable is (0,0,0)-colorable. Additionally, we exhibit
non-(3,1)-colorable planar graphs with girth 5 and non-(2,0)-colorable planar
graphs with girth 7.


title: Automorphisms of cluster algebras of rank 2

abstract:
  We compute the automorphism group of the affine surfaces with the coordinate
ring isomorphic to a cluster algebra of rank 2.


title: Extensions of Schur's irreducibility results

abstract:
  We prove that the generalised Laguerre polynomials $L_{n}^{(\alpha)}(x)$ with
$0\le \al\le 50$ are irreducible except for finitely many pairs $(n, \al)$ and
that these exceptions are necessary. In fact it follows from a more general
statement.


title:
Evaluating Wireless Reactive Routing Protocols with Linear Programming
  Model for Wireless Ad-hoc Networks

abstract:
  In Wireless Ad-hoc Networks, nodes are free to move randomly and organize
themselves arbitrarily, thus topology may change quickly and capriciously. In
Mobile Ad-hoc NETworks, specially Wireless Multi-hop Networks provide users
with facility of quick communication. In Wireless Multi-hop Networks, routing
protocols with energy efficient and delay reduction techniques are needed to
fulfill users demands. In this paper, we present Linear Programming models to
assess and enhance reactive routing protocols. To practically examine
constraints of respective Linear Programming models over reactive protocols, we
select AODV, DSR and DYMO. It is deduced from analytical simulations of Linear
Programming models in MATLAB that quick route repair reduces routing latency
and optimizations of retransmission attempts results efficient energy
utilization. To provide quick repair, we enhance AODV and DSR. To practically
examine the efficiency of enhanced protocols in different scenarios of Wireless
Multi-hop Networks, we conduct simulations using NS-2. From simulation results,
enhanced DSR and AODV achieve efficient output by optimizing routing latencies
and routing load in terms of retransmission attempts.


title:
Invisible stimuli, implicit thresholds: Why invisibility judgments
  cannot be interpreted in isolation

abstract:
  Some studies of unconscious cognition rely on judgments of participants
stating that they have "not seen" the critical stimulus (e.g., in a
masked-priming experiment). Trials in which participants gave "not-seen"
judgments are then treated as those where the critical stimulus was
"subliminal" or "unconscious", as opposed to trials with higher visibility
ratings. Sometimes, only these trials are further analyzed, for instance, for
unconscious priming effects. Here I argue that this practice requires implicit
assumptions about subjective measures of awareness incompatible with basic
models of categorization under uncertainty (e.g., modern signal-detection and
threshold theories). Most importantly, it ignores the potential effects of
response bias. Instead of taking "not-seen" judgments literally, they would
better be employed in parametric experiments where stimulus visibility is
manipulated systematically, not accidentally. This would allow studying
qualitative and double dissociations between measures of awareness and of
stimulus processing per se.


title:
Modeling and Simulating Network Connectivity in Routing Protocols for
  MANETs and VANETs

abstract:
  This paper presents a framework for node distribution with respect to
density, network connectivity and communication time. Using NS2, we evaluate
and compare performance of three routing protocols; Ad-hoc On-demand Distance
Vector (AODV), Dynamic Source Routing (DSR) and Fisheye State Routing (FSR)
both in MANETs (IEEE 802.11) and VANETs (IEEE 802.11p). We further enhanced
these protocols by changing their routing information exchange intervals; MOD
AODV, MOD DSR and MOD FSR. A comprehensive simulation work is performed for the
comparison of these routing protocols for varying motilities and scalabilities
of nodes. As a result, we can say that AODV outperforms DSR and FSR both in
MANETs and VANETs.


title: Some irreducibility results for truncated binomial expansions

abstract:
  For positive integers $n>k$, let $P_{n,k}(x)=\displaystyle\sum_{j=0}^k
\binom{n}{j}x^j $ be the polynomial obtained by truncating the binomial
expansion of $(1+x)^n$ at the $k^{th}$ stage. These polynomials arose in the
investigation of Schubert calculus in Grassmannians. In this paper, the authors
prove the irreducibility of $P_{n,k}(x)$ over the field of rational numbers
when $2\leqslant 2k \leqslant n<(k+1)^3$.


title:
Crystal field states in a Quantum Spin Ice]{Crystal field states of
  Pr$^{3+}$ in the candidate quantum spin ice Pr$_{2}$Sn$_{2}$O$_{7}$

abstract:
  Neutron time-of-flight spectroscopy has been employed to study the
crystal-field splitting of Pr$^{3+}$ in the pyrochlore stannate
Pr$_{2}$Sn$_{2}$O$_{7}$. The crystal field has been parameterized from a
profile fit to the observed neutron spectrum. The single-ion ground state is a
well isolated non-Kramers doublet of $\Gamma_3^+$ symmetry with a large
Ising-like anisotropy, $\chi_{zz} /\chi_\perp \approx 60$ at 10 K, but with a
significant admixture of terms $| M_J \neq \pm J >$ which can give rise to
quantum zero-point fluctuations. This magnetic state satisfies the requirements
for quantum spin ice behavior.


title:
Mashup of Meta-Languages and its Implementation in the Kermeta Language
  Workbench

abstract:
  With the growing use of domain-specific languages (DSL) in industry, DSL
design and implementation goes far beyond an activity for a few experts only
and becomes a challenging task for thousands of software engineers. DSL
implementation indeed requires engineers to care for various concerns, from
abstract syntax, static semantics, behavioral semantics, to extra-functional
issues such as run-time performance. This paper presents an approach that uses
one meta-language per language implementation concern. We show that the usage
and combination of those meta-languages is simple and intuitive enough to
deserve the term "mashup". We evaluate the approach by completely implementing
the non trivial fUML modeling language, a semantically sound and executable
subset of the Unified Modeling Language (UML).


title:
Evaluating and Comparing Probability of Path Loss in DSDV, OLSR and DYMO
  at 802.11 and 802.11p

abstract:
  In this paper, we present path loss model for VANETs and simulate three
routing protocols; Destination Sequenced Distance Vector (DSDV), Optimized Link
State Routing (OLSR) and Dynamic MANET On-demand (DYMO) to evaluate and compare
their performance using NS-2. The main contribution of this work is enhancement
of existing techniques to achieve high efficiency of the underlying networks.
After extensive simulations in NS-2, we conclude that DSDV best performs with
802.11p while DYMO gives outstanding performance with 802.11.


title: Detecting Missing Method Calls as Violations of the Majority Rule

abstract:
  When using object-oriented frameworks it is easy to overlook certain
important method calls that are required at particular places in code. In this
paper, we provide a comprehensive set of empirical facts on this problem,
starting from traces of missing method calls in a bug repository. We propose a
new system that searches for missing method calls in software based on the
other method calls that are observable. Our key insight is that the voting
theory concept of majority rule holds for method calls: a call is likely to be
missing if there is a majority of similar pieces of code where this call is
present. The evaluation shows that the system predictions go further missing
method calls and often reveal different kinds of code smells (e.g. violations
of API best practices).


title:
A Holder-logarithmic stability estimate for an inverse problem in two
  dimensions

abstract:
  The problem of the recovery of a real-valued potential in the two-dimensional
Schrodinger equation at positive energy from the Dirichlet-to-Neumann map is
considered. It is know that this problem is severely ill-posed and the
reconstruction of the potential is only logarithmic stable in general. In this
paper a new stability estimate is proved, which is explicitly dependent on the
regularity of the potentials and on the energy. Its main feature is an
efficient increasing stability phenomenon at sufficiently high energies: in
some sense, the stability rapidly changes from logarithmic type to Holder type.
The paper develops also several estimates for a non-local Riemann-Hilbert
problem which could be of independent interest.


title:
On measure solutions of the Boltzmann equation, Part II: Rate of
  convergence to equilibrium

abstract:
  The paper considers the convergence to equilibrium for measure solutions of
the spatially homogeneous Boltzmann equation for hard potentials with angular
cutoff. We prove the exponential sharp rate of strong convergence to
equilibrium for conservative measure solutions having finite mass and energy.
The proof is based on the regularizing property of the iterated collision
operators, exponential moment production estimates, and some previous results
on the exponential rate of strong convergence to equilibrium for square
integrable initial data. We also obtain a lower bound of the convergence rate
and deduce that no eternal solutions exist apart from the trivial stationary
solutions given by the Maxwellian equilibrium. We finally use these convergence
rates in order to deduce global-in-time strong stability of measure solutions.


title: Grimm's Conjecture and Smooth Numbers

abstract:
  Let $g(n)$ be the largest positive integer $k$ such that there are distinct
primes $p_i$ for $1\leq i\leq k$ so that $p_i |n+i$. This function is related
to a celebrated conjecture of C.A. Grimm. We establish upper and lower bounds
for $g(n)$ by relating its study to the distribution of smooth numbers.
Standard conjectures concerning smooth numbers in short intervals imply $g(n)
=O(n^\epsilon)$ for any $\epsilon >0$. We also prove unconditionally that $g(n)
=O(n^\al)$ with $0.45<\al <0.46$. The study of $g(n)$ and cognate functions has
some interesting implications for gaps between consecutive primes.


title:
Full-scale ab initio 3D PIC simulations of an all-optical radiation
  reaction configuration at $10^{21}\mathrm{W/cm^2}$

abstract:
  Using full-scale 3D particle-in-cell simulations we show that the radiation
reaction dominated regime can be reached in an all optical configuration
through the collision of a $\sim$1 GeV laser wakefield accelerated (LWFA)
electron bunch with a counter propagating laser pulse. In this configuration
radiation reaction significantly reduces the energy of the particle bunch, thus
providing clear experimental signatures for the process with currently
available lasers. We also show that the transition between classical and
quantum radiation reaction could be investigated in the same configuration with
laser intensities of $10^{24}\mathrm{W/cm^2}$.


title: Fast recognition of alternating groups of unknown degree

abstract:
  We present a constructive recognition algorithm to decide whether a given
black-box group is isomorphic to an alternating or a symmetric group without
prior knowledge of the degree. This eliminates the major gap in known
algorithms, as they require the degree as additional input.
  Our methods are probabilistic and rely on results about proportions of
elements with certain properties in alternating and symmetric groups. These
results are of independent interest; for instance, we establish a lower bound
for the proportion of involutions with small support.


title:
Covariance and Causality in the Transition Radiation of an Electron
  Bunch

abstract:
  A theoretical model of the transition radiation (TR) emission of an N
electron bunch must comply with the covariance and the temporal-causality
principles. A charge-density-like covariance must indeed imprint the formal
expression of the TR energy spectrum. A causality relation must constrain the
emission phases of the radiation pulse to the temporal sequence of the N
electron collisions onto the metallic screen. Covariance and causality are the
two faces of the same coin: failing in implementing one of the two constraints
into the model necessarily implies betraying the other one. The main formal
aspects of a covariance and causality consistent formulation of the TR energy
spectrum of an N electron beam will be here described with reference to the
case of a radiator surface with an arbitrary size.


title:
Numerical simulation of wave impact on a rigid wall using a two-phase
  compressible SPH method

abstract:
  In this paper, an SPH method based on the SPH-ALE formulation is used for
modelling two-phase flows with large density ratios and realistic sound speeds.
The SPH scheme is further improved to circumvent the tensile instability that
may occur in the SPH simulations. The two-phase SPH solver is then used to
model a benchmark problem of liquid impact on a rigid wall. The results are
compared with an incompressible Level Set solver. Furthermore, a wave impact on
a rigid wall with a large entrained air pocket is modelled. The SPH simulation
is initialised by the output of a fully non-linear potential flow solver. The
pressure distribution, velocity field and impact pressure are then analysed.

categories: physics.flu-dyn cs.NA math.NA physics.comp-ph


title: Direct Phasing of Nanocrystal Diffraction

abstract:
  Recent experiments at free-electron laser x-ray sources have been able to
resolve the intensity distributions about Bragg peaks in nanocrystals of large
biomolecules. Information derived from small shifts in the peak positions
augment the Bragg samples of the particle intensity with samples of its
gradients. Working on the assumption that the nanocrystal is entirely generated
by lattice translations of a particle, we develop an algorithm that
reconstructs the particle from intensities and intensity gradients. Unlike
traditional direct phasing methods that require very high resolution data in
order to exploit sparsity of the electron density, our method imposes no
constraints on the contrast other than positivity and works well at low
resolution. We demonstrate successful reconstructions with simulated P1
lysozyme nanocrystal data down to a signal-to-noise ratio of 2 in the intensity
gradients.


title:
The Frequent Items Problem in Online Streaming under Various Performance
  Measures

abstract:
  In this paper, we strengthen the competitive analysis results obtained for a
fundamental online streaming problem, the Frequent Items Problem. Additionally,
we contribute with a more detailed analysis of this problem, using alternative
performance measures, supplementing the insight gained from competitive
analysis. The results also contribute to the general study of performance
measures for online algorithms. It has long been known that competitive
analysis suffers from drawbacks in certain situations, and many alternative
measures have been proposed. However, more systematic comparative studies of
performance measures have been initiated recently, and we continue this work,
using competitive analysis, relative interval analysis, and relative worst
order analysis on the Frequent Items Problem.


title: Equivalence and comparison of heterogeneous cellular networks

abstract:
  We consider a general heterogeneous network in which, besides general
propagation effects (shadowing and/or fading), individual base stations can
have different emitting powers and be subject to different parameters of
Hata-like path-loss models (path-loss exponent and constant) due to, for
example, varying antenna heights. We assume also that the stations may have
varying parameters of, for example, the link layer performance (SINR threshold,
etc). By studying the propagation processes of signals received by the typical
user from all antennas marked by the corresponding antenna parameters, we show
that seemingly different heterogeneous networks based on Poisson point
processes can be equivalent from the point of view a typical user. These
neworks can be replaced with a model where all the previously varying
propagation parameters (including path-loss exponents) are set to constants
while the only trade-off being the introduction of an isotropic base station
density. This allows one to perform analytic comparisons of different network
models via their isotropic representations. In the case of a constant path-loss
exponent, the isotropic representation simplifies to a homogeneous modification
of the constant intensity of the original network, thus generalizing a previous
result showing that the propagation processes only depend on one moment of the
emitted power and propagation effects. We give examples and applications to
motivate these results and highlight an interesting observation regarding
random path-loss exponents.


title:
Modeling of multiple three phase contact lines of liquid droplets on
  geometrically patterned surfaces: continuum and mesoscopic analysis

abstract:
  By solving the Young Laplace equation of capillary hydrostatics one can
accurately determine equilibrium shapes of droplets on relatively smooth solid
surfaces. The solution, however of the Young Laplace equation becomes tricky
when a droplet is sitting on a geometrically patterned surface and multiple,
and unknown a priori, three phase contact lines have not been accounted for,
since air pockets are trapped beneath the liquid droplet. In this work, we
propose an augmented Young-Laplace equation, in which a unified formulation for
the liquid/vapor and liquid/solid interfaces is adopted, incorporating
microscale interactions. This way, we bypass the implementation of the Young's
contact angle boundary condition at each three phase contact line. We
demonstrate the method's efficiency by computing equilibrium wetting states of
entire droplets sitting on geometrically structured surfaces, and compare the
results with those of the mesoscopic Lattice Boltzmann simulations. The
application of well-established parameter continuation techniques enables the
tracing of stable and unstable equilibrium solutions if necessary for the
determination of energy barriers separating co-existing stable wettign states.
Since energy barriers determine whether a surface facilitates or inhibits
certain wetting transitions, their computation is important for many technical
applications. Our continuum-level analysis can readily be applied to patterned
surfaces with increased and unstructured geometric complexity, having a
significant computational advantage, as compared to the computationally
demanding mesoscopic simulations that are usually employed for the same task.


title: Extreme-mass-ratio-bursts from extragalactic sources

abstract:
  Extreme-mass-ratio bursts (EMRBs) are a class of potentially interesting
gravitational wave signals. They are produced when a compact object passes
through periapsis on a highly eccentric orbit about a much more massive object;
we consider stellar mass objects orbiting the massive black holes (MBHs) found
in galactic centres. Such a system may emit many EMRBs before eventually
completing the inspiral. There are several nearby galaxies that could yield
detectable bursts. For a space-borne interferometer like the Laser
Interferometer Space Antenna, sensitivity is greatest for EMRBs from MBHs of
~10^6-10^7 solar masses, which could be detected out to ~100 Mpc. Considering
the examples of M32, NGC 4945 and NGC 4395 we investigate if extragalactic EMRB
signals can provide information about their sources. This is possible, but only
if the periapse radius of the orbit is small, of the order of r_p < 8 r_g,
where r_g = GM/c^2 is the gravitational radius of the MBH. This limits the
utility of EMRBs as an astronomical tool. However, if we are lucky, we could
place constraints on the mass and spin of nearby MBHs with 1% precision.

categories: astro-ph.HE astro-ph.CO astro-ph.GA gr-qc


title: The 2-color Rado Number of $x_1+x_2+\cdots +x_{m-1}=ax_m,$ II

abstract:
  In the first installment of this series, we proved that, for every integer
$a\geq 3$ and every $m\geq 2a^2-a+2$, the 2-color Rado number of $x_1 + x_2 +
\cdots + x_{m-1} = ax_m$ is $\lceil\frac{m-1}{a} \lceil\frac{m-1}{a}
\rceil\rceil$. Here we obtain the best possible improvement of the bound on
$m.$ We prove that if $3|a$ then the 2-color Rado number is
$\lceil\frac{m-1}{a} \lceil\frac{m-1}{a} \rceil\rceil$ when $m\geq 2a+1$ but
not when $m=2a,$ and that if $3\nmid a$ then the 2-color Rado number is
$\lceil\frac{m-1}{a} \lceil\frac{m-1}{a} \rceil\rceil$ when $m\geq 2a+2$ but
not when $m=2a+1.$ We also determine the 2-color Rado number for all $a\geq 3$
and $m\geq \frac{a}{2}+1.$


title: Nanolayer thickness detection via spatial mode projection

abstract:
  We demonstrate an optical scheme for measuring the thickness of thin
nanolayers with the use of light beam s spatial modes. The novelty in our
scheme is the projection of the beam reflected by the sample onto a
properly-tailored spatial mode. In the experiment described below, we are able
to measure a step height smaller than 10 nm, i.e., one-eightieth (1/80)of the
wavelength with a standard error in the picometer scale. Since our scheme
enhances the signal-to-noise ratio (SNR), which effectively increases the
sensitivity of detection, the extension of this technique to the detection of
subnanometric layer thicknesses is feasible.


title:
Catching Spiral - S0 transition in groups. Insights from SPH simulations
  with chemo-photometric implementation

abstract:
  We are investigating the co-evolution of galaxies within groups combining
multi-wavelength photometric and 2D kinematical observations. Here we focus on
S0s showing star formation in ring/arm-like structures. We use smooth particle
hydrodynamical simulations (SPH) with chemo-photometric implementation which
provide dynamical and morphological information together with the spectral
energy distribution (SED) at each evolutionary stage. As test cases, we
simulate the evolution of two such S0s: NGC 1533 and NGC 3626. The merging of
two halos with mass ratio 2:1, initially just composed of dark matter (DM) and
gas, well match their observed SEDs, their surface brightness profiles and
their overall kinematics. The residual star formation today "rejuvenating" the
ring/arm like structures in these S0s is then a mere consequence of a major
merger, i.e. this is a phase during the merger episode. The peculiar
kinematical features, e.g. gas-stars counter rotation in NGC 3626, depends on
the halos initial impact parameters. Furthermore, our simulations allow to
follow, in a fully consistent way, the transition of these S0s through the
green valley in the NUV-r vs. Mr colour magnitude diagram, which they cross in
about 3-5 Gyr, before reaching their current position in the red sequence. We
conclude that a viable mechanism driving the evolution of S0s in groups is of
gravitational origin.


title: Algebra and logic. Some problems

abstract:
  The paper has a form of a talk on the given topic. It consists of three
parts.
  The first part of the paper contains main notions, the second one is devoted
to logical geometry, the third part describes types and isotypeness. The
problems are distributed in the corresponding parts. The whole material
oriented towards universal algebraic geometry (UAG), i.e., geometry in an
arbitrary variety of algebras $\Theta$. We consider logical geometry (LG) as a
part of UAG. This theory is strongly influenced by model theory and ideas of
A.Tarski and A.I.Malcev.


title: Cosmic slowing down of acceleration using $f_{gas}$

abstract:
  We investigate the recent - low redshift - expansion history of the universe
using the most recent observational data. Using only data from 42 measurements
of $f_{gas}$ in clusters, we found that cosmic acceleration could have already
peaked and we are witnessing now its slowing down. This effect, found
previously by Shafieloo, Sahni and Starobinsky in 2010 using supernova data (at
that time the Constitution SNIa sample) appears again using an independent
observational probe. We also discuss the result using the most recent Union 2.1
data set.


title: Regularizing infinite sums of zeta-determinants

abstract:
  We present a new multiparameter resolvent trace expansion for elliptic
operators, polyhomogeneous in both the resolvent and auxiliary variables. For
elliptic operators on closed manifolds the expansion is a simple consequence of
the parameter dependent pseudodifferential calculus. As an additional
nontrivial toy example we treat here Sturm-Liouville operators with separated
boundary conditions.
  As an application we give a new formula, in terms of regularized sums, for
the zeta-determinant of an infinite direct sum of Sturm-Liouville operators.
The Laplace-Beltrami operator on a surface of revolution decomposes into an
infinite direct sum of Sturm-Louville operators, parametrized by the
eigenvalues of the Laplacian on the cross-section. We apply the polyhomogeneous
expansion to equate the zeta-determinant of the Laplace-Beltrami operator as a
regularized sum of zeta-determinants of the Sturm-Liouville operators plus a
locally computable term from the polyhomogeneous resolvent trace asymptotics.
This approach provides a completely new method for summing up zeta-functions of
operators and computing the meromorphic extension of that infinite sum to s=0.
  We expect out method to extend to a much larger class of operators.


title: Dual Lie Bialgebras of Witt and Virasoro Types

abstract:
  Structures of dual Lie bialgebras on the one sided Witt algebra, the Witt
algebra and the Virasoro algebra are investigated. As a result, we obtain some
infinite dimensional Lie algebras.


title: From Coherent Modes to Turbulence and Granulation of Trapped Gases

abstract:
  The process of exciting the gas of trapped bosons from an equilibrium initial
state to strongly nonequilibrium states is described as a procedure of symmetry
restoration caused by external perturbations. Initially, the trapped gas is
cooled down to such low temperatures, when practically all atoms are in
Bose-Einstein condensed state, which implies the broken global gauge symmetry.
Excitations are realized either by imposing external alternating fields,
modulating the trapping potential and shaking the cloud of trapped atoms, or it
can be done by varying atomic interactions by means of Feshbach resonance
techniques. Gradually increasing the amount of energy pumped into the system,
which is realized either by strengthening the modulation amplitude or by
increasing the excitation time, produces a series of nonequilibrium states,
with the growing fraction of atoms for which the gauge symmetry is restored. In
this way, the initial equilibrium system, with the broken gauge symmetry and
all atoms condensed, can be excited to the state, where all atoms are in the
normal state, with completely restored gauge symmetry. In this process, the
system, starting from the regular superfluid state, passes through the states
of vortex superfluid, turbulent superfluid, heterophase granular fluid, to the
state of normal chaotic fluid in turbulent regime. Both theoretical and
experimental studies are presented.


title: Theorem of three circles in Coq

abstract:
  The theorem of three circles in real algebraic geometry guarantees the
termination and correctness of an algorithm of isolating real roots of a
univariate polynomial. The main idea of its proof is to consider polynomials
whose roots belong to a certain area of the complex plane delimited by straight
lines. After applying a transformation involving inversion this area is mapped
to an area delimited by circles. We provide a formalisation of this rather
geometric proof in Ssreflect, an extension of the proof assistant Coq,
providing versatile algebraic tools. They allow us to formalise the proof from
an algebraic point of view.