title:
A Lower Bound on the Noncoherent Capacity Pre-log for the MIMO Channel
  with Temporally Correlated Fading

abstract:
  We derive a lower bound on the capacity pre-log of a temporally correlated
Rayleigh block-fading multiple-input multiple-output (MIMO) channel with T
transmit antennas and R receive antennas in the noncoherent setting (no a
priori channel knowledge at the transmitter and the receiver). In this model,
the fading process changes independently across blocks of length L and is
temporally correlated within each block for each transmit-receive antenna pair,
with a given rank Q of the corresponding correlation matrix. Our result implies
that for almost all choices of the coloring matrix that models the temporal
correlation, the pre-log can be lower-bounded by T(1-1/L) for T <= (L-1)/Q
provided that R is sufficiently large. The widely used constant block-fading
model is equivalent to the temporally correlated block-fading model with Q = 1
for the special case when the temporal correlation for each transmit-receive
antenna pair is the same, which is unlikely to be observed in practice. For the
constant block-fading model, the capacity pre-log is given by T(1-T/L), which
is smaller than our lower bound for the case Q = 1. Thus, our result suggests
that the assumptions underlying the constant block- fading model lead to a
pessimistic result for the capacity pre-log.


title:
N coupled non-local harmonic oscillators leading to 2N-th order initial
  value problem

abstract:
  We consider a set of interwoven harmonic oscillators where the acceleration
of a given oscillator is determined by the position of its nearest neighbor. We
show that this problem of N non-local oscillators with periodic boundary
conditions leads to a 2N-th order initial value problem. We discuss the
numerical solution of this using a non-polynomial spline method. A very precise
numerical method that minimizes the error can be developed, which we test for a
few examples of driving forces.


title: On numerically hypercyclic operators

abstract:
  According to Kim, Peris and Song, a continuous linear operator $T$ on a
complex Banach space $X$ is called {\it numerically hypercyclic} if the
numerical orbit $\{f(T^nx):n\in\N\}$ is dense in $\C$ for some $x\in X$ and
$f\in X^*$ satisfying $\|x\|=\|f\|=f(x)=1$. They have characterized numerically
hypercyclic weighted shifts and provided an example of a numerically
hypercyclic operator on $\C^2$.
  We answer two questions of Kim, Peris and Song. Namely, we construct a
numerically hypercyclic operator, whose square is not numerically hypercyclic
as well as an operator which is not numerically hypercyclic but has two
numerical orbits whose union is dense in $\C$. We characterize numerically
hypercyclic operators on $\C^2$ as well as the operators similar to a
numerically hypercyclic one and those operators whose conjugacy class consists
entirely of numerically hypercyclic operators. We describe in spectral terms
the operator norm closure of the set of numerically hypercyclic operators on a
reflexive Banach space. Finally, we provide criteria for numeric hypercyclicity
and decide upon the numerical hypercyclicity of operators from various classes.


title:
Hofstadter butterflies and magnetically induced band gap quenching in
  graphene antidot lattices

abstract:
  We study graphene antidot lattices (GALs) in magnetic fields. Using a
tight-binding model and a recursive Green's function technique that we extend
to deal with periodic structures, we calculate Hofstadter butterflies of GALs.
We compare the results to those obtained in a simpler gapped graphene model. A
crucial difference emerges in the behaviour of the lowest Landau level, which
in a gapped graphene model is independent of magnetic field. In stark contrast
to this picture, we find that in GALs the band gap can be completely closed by
applying a magnetic field. While our numerical simulations can only be
performed on structures much smaller than can be experimentally realized, we
find that the critical magnetic field for which the gap closes can be directly
related to the ratio between the cyclotron radius and the neck width of the
GAL. In this way, we obtain a simple scaling law for extrapolation of our
results to more realistically sized structures and find resulting quenching
magnetic fields that should be well within reach of experiments.


title: An ab initio variationally computed room-temperature line list for SO3

abstract:
  {\it Ab initio} potential energy and dipole moment surfaces are computed for
sulfur trioxide (SO$_3$) at the CCSD(T)-F12b level of theory and appropriate
triple-zeta basis sets. These surfaces are fitted and used, with a slight
correction for the equilibrium S--O distance, to compute pure rotational and
rotation-vibraton spectra of \sothree\ using the variational nuclear motion
program TROVE. The calculations considered transitions in the region 0--4000
\cm\ with rotational states up to J=85. The resulting line list of 349~348~513
transitions is appropriate for modelling room temperature SO3 spectra. Good
agreement is found with the observed infrared absorption spectra and the
calculations are used to place the measured relative intensities on an absolute
scale. A list of 10~878 experimental transitions is provided in a form suitable
for inclusion in standard atmospheric and planetary spectroscopic databases.


title: The doubling map with asymmetrical holes

abstract:
  Let $0<a<b<1$ and let $T$ be the doubling map. Set $\mathcal
J(a,b):=\{x\in[0,1] : T^nx\notin (a,b), n\ge0\}$. In this paper we completely
characterize the holes $(a,b)$ for which any of the following scenarios holds:
{enumerate} $\mathcal J(a,b)$ contains a point $x\in(0,1)$; $\mathcal
J(a,b)\cap [\de,1-\de]$ is infinite for any fixed $\de>0$; $\mathcal J(a,b)$ is
uncountable of zero Hausdorff dimension; $\mathcal J(a,b)$ is of positive
Hausdorff dimension. {enumerate} In particular, we show that (iv) is always the
case if \[ b-a<\frac14\prod_{n=1}^\infty \bigl(1-2^{-2^n}\bigr)\approx 0.175092
\] and that this bound is sharp. As a corollary, we give a full description of
first and second order critical holes introduced in \cite{SSC} for the doubling
map.
  Furthermore, we show that our model yields a continuum of "routes to chaos"
via arbitrary sequences of products of natural numbers, thus generalizing the
standard route to chaos via period doubling.


title:
Phase stability of chromium based compensated ferrimagnets with inverse
  Heusler structure

abstract:
  Chromium based inverse Heusler compounds of the type Cr2YZ (Y=Co, Fe; Z=Al,
Ga, In, Si, Ge, Sn) have been proposed as fully compensated half-metallic
ferrimagnets. Such materials are of large interest for spintronics because they
combine small magnetic moment with high spin polarization over a wide
temperature range. We assess their thermodynamic stability by their formation
enthalpies obtained from density functional theory calculations. All compounds
under investigation are unstable. Cr2FeSi and Cr2CoAl are stable with respect
to the elemental constituents, but decompose into binary phases. Cr2FeGe,
Cr2CoGa, Cr2FeSn and Cr2CoIn are found to be unstable with respect to their
elemental constituents. We identify possible binary decompositions.


title:
On Semiclassical Equivalence of Green-Schwarz and Pure Spinor Strings in
  AdS(5) x S(5)

abstract:
  We present a method to study the equivalence at the semiclassical level of
the Green-Schwarz and pure spinor formulations of String Theory in AdS(5) x
S(5). This method provides a clear separation of the physical and unphysical
sectors of the pure spinor formulation and allows one to prove that the two
models have not only equal spectra for the fermionic fluctuations but also
equal conformal weights (the bosonic ones being equal by construction).


title: Adaptive-treed bandits

abstract:
  We describe a novel algorithm for noisy global optimisation and
continuum-armed bandits, with good convergence properties over any continuous
reward function having finitely many polynomial maxima. Over such functions,
our algorithm achieves square-root regret in bandits, and inverse-square-root
error in optimisation, without prior information. Our algorithm works by
reducing these problems to tree-armed bandits, and we also provide new results
in this setting. We show it is possible to adaptively combine multiple trees so
as to minimise the regret, and also give near-matching lower bounds on the
regret in terms of the zooming dimension.


title: Frames and operators in Schatten classes

abstract:
  Let $T$ be a compact operator on a separable Hilbert space $H$. We show that,
for $2\le p<\infty$, $T$ belongs to the Schatten class $S_p$ if and only if
$\{\|Tf_n\|\}\in \ell^p$ for \emph{every} frame $\{f_n\}$ in $H$; and for
$0<p\le2$, $T$ belongs to $S_p$ if and only if $\{\|Tf_n\|\}\in\ell^p$ for
\emph{some} frame $\{f_n\}$ in $H$. Similar conditions are also obtained in
terms of the sequence $\{<Tf_n,f_n>\}$ and the double-indexed sequence
$\{<Tf_n,f_m>\}$.


title:
Terahertz spectroscopy of spin waves in multiferroic BiFeO$_3$ in high
  magnetic fields

abstract:
  We have studied the magnetic field dependence of far-infrared active magnetic
modes in a single ferroelectric domain \BFO/ crystal at low temperature. The
modes soften close to the critical field of 18.8\,T along the [001]
(pseudocubic) axis, where the cycloidal structure changes to the homogeneous
canted antiferromagnetic state and a new strong mode with linear field
dependence appears that persists at least up to 31\,T. A microscopic model that
includes two \DM/ interactions and easy-axis anisotropy describes closely both
the zero-field spectroscopic modes as well as their splitting and evolution in
a magnetic field. The good agreement of theory with experiment suggests that
the proposed model provides the foundation for future technological
applications of this multiferroic material.


title: A Metal-Rich Low-Gravity Companion to a Massive Millisecond Pulsar

abstract:
  Most millisecond pulsars with low-mass companions are in systems with either
helium-core white dwarfs or non-degenerate ("black widow" or "redback") stars.
A candidate counterpart to PSR J1816+4510 was identified by Kaplan et al.
(2012) whose properties were suggestive of both types of companions although
identical to neither. We have assembled optical spectroscopy of the candidate
companion and confirm that it is part of the binary system with a radial
velocity amplitude of 343+/-7 km/s, implying a high pulsar mass,
Mpsr*sin^3i=1.84+/-0.11 Msun, and a companion mass Mc*sin^3i=0.192+/-0.012
Msun, where i is the inclination of the orbit. The companion appears similar to
proto-white dwarfs/sdB stars, with a gravity log(g)=4.9+/-0.3, and effective
temperature 16000+/-500 K. The strongest lines in the spectrum are from
hydrogen, but numerous lines from helium, calcium, silicon, and magnesium are
present as well, with implied abundances of roughly ten times solar (relative
to hydrogen). As such, while from the spectrum the companion to PSR J1816+4510
is superficially most similar to a low-mass white dwarf, it has much lower
gravity, is substantially larger, and shows substantial metals. Furthermore, it
is able to produce ionized gas eclipses, which had previously been seen only
for low-mass, non-degenerate companions in redback or black widow systems. We
discuss the companion in relation to other sources, but find we understand
neither its nature nor its origins. Thus, the system is interesting for
understanding unusual stellar products of binary evolution, as well as,
independent of its nature, for determining neutron-star masses.


title:
Evaluation on the Financial Competitiveness of Chinese Listed Real
  Estate Companies Based on Entropy Method

abstract:
  The real estate is a pillar industry of China's national economy. Due to
changes in policy and market conditions, the real estate companies are facing
greater pressures to survive in a competitive environment. They must improve
their financial competitiveness. Based on the conceptual framework of financial
competitiveness, this paper presented a financial competitiveness evaluation
index system, covering four aspects, including profitability, solvency,
sustainable development and operational capacity. Entropy value method is
applied to determine the index weight. 105 listed real estate company's
financial competitiveness are evaluated, the results show that: high-scoring
company has strong profitability, sustainable development and operational
capacity; low-scoring company has weak profitability and poor ability of
sustainable development; solvency doesn't affect the company's financial
competitiveness obviously.


title:
Superbubble dynamics in globular cluster infancy II. Consequences for
  secondary star formation in the context of self-enrichment via fast rotating
  massive stars

abstract:
  The self-enrichment scenario for globular clusters (GC) requires large
amounts of residual gas after the initial formation of the first stellar
generation. Recently, Krause et al. (2012) found that supernovae may not be
able to expel that gas, as required to explain their present day gas-free
state, and suggested that a sudden accretion on to the dark remnants, at a
stage when type II supernovae have ceased, may plausibly lead to fast gas
expulsion. Here, we explore the consequences of these results for the
self-enrichment scenario via fast rotating massive stars (FRMS). We analyse the
interaction of FRMS with the intra-cluster medium (ICM), in particular where,
when and how the second generation of stars may form. From the results, we
develop a timeline of the first approximately 40 Myr of GC evolution. The
results of Paper I imply three phases during which the ICM is in a
fundamentally different state, namely the wind bubble phase (lasting 3.5 to 8.8
Myr), the supernova phase (lasting 26.2 to 31.5 Myr), and the dark remnant
accretion phase (lasting 0.1 to 4 Myr): (i) Quickly after the first generation
massive stars have formed, stellar wind bubbles compress the ICM into thin
filaments. No stars may form in the normal way during this phase, due to the
high Lyman-Werner flux density. If the first generation massive stars have
however equatorial ejections, as we proposed in the FRMS scenario, accretion
may resume in the shadow of the equatorial ejecta. The second generation stars
may then form due to gravitational instability in these discs that are fed by
both the FRMS ejecta and pristine gas. [...]


title:
Instability of flat disks with respect to the formation of twisted
  ribbons in smectic-A monolayers

abstract:
  Smectic-A monolayers self-assembled from aqueous solutions of chiral fd
viruses and a polymer depletant can assume a variety of shapes such as flat
disks and twisted ribbons. A theoretical model based on the de Gennes model for
the smectic A phase, the Helfrich model of membrane elasticity and a simple
edge energy has been previously used to calculate the disk-ribbon phase
diagram. In this paper we apply this model to the nucleation process of
ribbons. First, we study the "rippled disks" that have been observed as
precursors of ribbons. Using a model shape proposed by Meyer which includes
rippling in both the in-plane and out of plane directions, we study the
energetics of the disks as functions of the edge energy modulus (a measure of
the polymer concentration) and the mean curvature modulus k. We find that as
the edge energy modulus is reduced the radial size of the ripples grows rapidly
in agreement with experimental observations. For small enough k we find that
the out of plane size of the ripples grows but its value saturates at a
fraction of the twist penetration depth, too small to be experimentally
observable. For large k the membrane remains flat though rippled in the radial
direction. Such membranes do not have negative Gaussian curvature and thus will
not likely spawn twisted ribbons. We also study the creation of twisted ribbons
produced by stretching the edge of a flat membrane in a localized region. In
experiments using a pair of optical traps it has been observed that once the
membrane has been sufficiently stretched a ribbon forms on the stretched edge.
We study this process theoretically using a free energy consisting of the
Helfrich and edge energies alone. We add a small ribbon-like perturbation to
the protrusion producd by stretching and determine whether it is energetically
favorable as a function of the size of the protrusion.


title: A Counterexample to Guillemin's Zollfrei Conjecture

abstract:
  We construct Zollfrei Lorentzian metrics on every nontrivial orientable
circle bundle over a orientable closed surface. Further we prove a weaker
version of Guillemin's conjecture assuming global hyperbolicity of the
universal cover.


title:
On the number of terms in the middle of almost split sequences over
  cycle-finite artin algebras

abstract:
  We prove that the number of terms in the middle of an almost split sequence
in the module category of a cycle-finite artin algebra is bounded by 5.


title: Realization of Einsteins Machian Program

abstract: The Einsteins Machian Program is here accomplished.


title:
Periodic and Chaotic Traveling Wave Patterns in Reaction-Diffusion/
  Predator-Prey Models with General Nonlinearities

abstract:
  Traveling wavetrains in generalized two-species predator-prey models and
two-component reaction-diffusion equations are considered. The stability of the
fixed points of the traveling wave ODEs (in the usual "spatial" variable) is
considered. For general functional forms of the nonlinear prey birthrate/prey
deathrate or reaction terms, a Hopf bifurcation is shown to occur at two
different critical values of the traveling wave speed. The post-bifurcation
dynamics is investigated for five different functional forms of the
nonlinearities. In cases where the bifurcation is supercritical, the
post-bifurcation behaviour yields stable periodic orbits of the traveling-wave
ODEs in the spatial variable. These correspond to stable periodic wavetrains of
the full PDEs. Subcritical Hopf bifurcations yield more complex
post-bifurcation dynamics in the PDE wavetrains. In special cases where the
subcritical bifurcation marks the end of the regime of stability, the
post-bifurcation behavior in the spatial ODEs is chaotic, corresponding to
wavetrains of the original PDEs which are spatially coherent, but have chaotic
temporal dynamics. All the models are integrated numerically to investigate the
post-bifurcation dynamics and chaotic regimes are characterized by computing
power spectra, autocorrelation functions, and fractal dimensions.


title:
Constructing a Stochastic Model of Bumblebee Flights from Experimental
  Data

abstract:
  The movement of organisms is subject to a multitude of influences of widely
varying character: from the bio-mechanics of the individual, over the
interaction with the complex environment many animals live in, to evolutionary
pressure and energy constraints. As the number of factors is large, it is very
hard to build comprehensive movement models. Even when movement patterns in
simple environments are analysed, the organisms can display very complex
behaviours. While for largely undirected motion or long observation times the
dynamics can sometimes be described by isotropic random walks, usually the
directional persistence due to a preference to move forward has to be accounted
for, e.g., by a correlated random walk. In this paper we generalise these
descriptions to a model in terms of stochastic differential equations of
Langevin type, which we use to analyse experimental search flight data of
foraging bumblebees. Using parameter estimates we discuss the differences and
similarities to correlated random walks. From simulations we generate
artificial bumblebee trajectories which we use as a validation by comparing the
generated ones to the experimental data.


title:
Optimal Forgery and Suppression of Ratings for Privacy Enhancement in
  Recommendation Systems

abstract:
  Recommendation systems are information-filtering systems that tailor
information to users on the basis of knowledge about their preferences. The
ability of these systems to profile users is what enables such intelligent
functionality, but at the same time, it is the source of serious privacy
concerns. In this paper we investigate a privacy-enhancing technology that aims
at hindering an attacker in its efforts to accurately profile users based on
the items they rate. Our approach capitalizes on the combination of two
perturbative mechanisms---the forgery and the suppression of ratings. While
this technique enhances user privacy to a certain extent, it inevitably comes
at the cost of a loss in data utility, namely a degradation of the
recommendation's accuracy. In short, it poses a trade-off between privacy and
utility.
  The theoretical analysis of said trade-off is the object of this work. We
measure privacy as the Kullback-Leibler divergence between the user's and the
population's item distributions, and quantify utility as the proportion of
ratings users consent to forge and eliminate. Equipped with these quantitative
measures, we find a closed-form solution to the problem of optimal forgery and
suppression of ratings, and characterize the trade-off among privacy, forgery
rate and suppression rate. Experimental results on a popular recommendation
system show how our approach may contribute to privacy enhancement.


title: Eulerian and Newtonian dynamics of quantum particles

abstract:
  We derive the classical equations of hydrodynamic type (Euler equation and
the continuity equation) from which the Schrodinger equation follows as a limit
case. It is shown that the statistical ensemble corresponding to quantum system
and described by the Schrodinger equation, can be considered as an inviscid gas
obeying the ideal gas law with quickly oscillating sign-alternating
temperature. This statistical ensemble performs the complex movements
consisting of smooth average movement and fast oscillations. It is shown that
average movements of statistical ensemble are described by Schrodinger
equation. A model of quantum motion within the limits of classical mechanics
which corresponds to the considered hydrodynamic system is suggested.


title: Dirac cohomology of unipotent representations of Sp(2n,R) and U(p,q)

abstract:
  In this paper we study the problem of computing the Dirac cohomology of the
special unipotent representations of the real groups Sp(2n,R) and U(p,q).


title: Some Determinantal Identities

abstract:
  Some applications of a result, which is proved recently, is considered. We
first prove three determinantal identities concerning the binomial coefficient
and Stirling numbers of the first and the second kind. We also easily obtain
the inverse of the Vandermonde matrix. Then we derive a recurrence formula for
sums of powers, which is similar to the well-known Newton identity. In the last
section, we consider some sequences given by a homologous linear recurrence
equation.
  A determinantal identity for the Fibonacci numbers of higher order is proved.
  We finish with an expression of the generalized Vandermonde determinant in
terms of the standard Vandermonde determinant and elementary symmetric
polynomials.


title:
Localized Function Method Based on the Galerkin Method Applying a Set of
  Sine Functions to Model Photonic Crystal Fibres

abstract:
  A development and an application of the localized function method based on
the Galerkin method applying a set of Sine functions to approximate the unknown
mode fields of the localized modes propagating along the photonic crystal
fibres is proposed. A way for considerably reducing the number of integrals in
the case of symmetrical holes shapes with respect to the axes of coordinate
systems located at the centers of the holes, circular, elliptical etc., is also
presented. The method does not require an expansion of the refractive index and
thus inaccuracies of the expansion can be avoided. In the case of a circular
form of the holes all integrals are solved analytically.


title: Outline of the proof of the geometric Langlands conjecture for GL(2)

abstract:
  We outline a proof of the categorical geometric Langlands conjecture for
GL(2), as formulated in reference [AG], modulo a number of more tractable
statements that we call Quasi-Theorems.


title: Spectral gap of the Erlang A model in the Halfin-Whitt regime

abstract:
  We consider a hybrid diffusion process that is a combination of two
Ornstein-Uhlenbeck processes with different restraining forces. This process
serves as the heavy-traffic approximation to the Markovian many-server queue
with abandonments in the critical Halfin-Whitt regime. We obtain an expression
for the Laplace transform of the time-dependent probability distribution, from
which the spectral gap is explicitly characterized. The spectral gap gives the
exponential rate of convergence to equilibrium. We further give various
asymptotic results for the spectral gap, in the limits of small and large
abandonment effects. It turns out that convergence to equilibrium becomes
extremely slow for overloaded systems with small abandonment effects.


title: Factorization identities for reflected processes, with applications

abstract:
  We derive factorization identities for a class of preemptive-resume queueing
systems, with batch arrivals and catastrophes that, whenever they occur,
eliminate multiple customers present in the system. These processes are quite
general, as they can be used to approximate Levy processes, diffusion
processes, and certain types of growth-collapse processes; thus, all of the
processes mentioned above also satisfy similar factorization identities. In the
Levy case, our identities simplify to both the well-known Wiener-Hopf
factorization, and another interesting factorization of reflected Levy
processes starting at an arbitrary initial state. We also show how the ideas
can be used to derive transforms for some well-known
state-dependent/inhomogeneous birth-death processes and diffusion processes.


title: The Dense Stellar Systems Around Galactic Massive Black Holes

abstract:
  The central regions of galaxies show the presence of massive black holes
and/or dense stellar systems. The question about their modes of formation is
still under debate. A likely explanation of the formation of the central dense
stellar systems in both spiral and elliptical galaxies is based on the orbital
decay of massive globular clusters in the central region of galaxies due to
kinetic energy dissipation by dynamical friction. Their merging leads to the
formation of a nuclear star cluster, like that of the Milky Way, where a
massive black hole (Sgr A*) is also present. Actually, high precision N-body
simulations (Antonini, Capuzzo-Dolcetta et al. 2012, ApJ, 750, 111) show a good
fit to the observational characteristics of the Milky Way nuclear cluster,
giving further reliability to the cited `migratory' model for the formation of
compact systems in the inner galaxy regions.


title:
A Very Long Baseline Interferometry Detection of the Class I Protostar
  IRS 5 in Corona Australis

abstract:
  Aims: Very Long Baseline Interferometry yields physical constraints on the
compact radio emission of young stellar objects. At the same time, such
measurements can be used for precise astrometric measurements of parallaxes and
proper motions. Here, we aimed to make the first detections of very compact
radio emission from class I protostars in the Corona Australis star-forming
region. Methods: We have used the Long Baseline Array (LBA) to observe the
protostars IRS 5 and IRS 7 in the Corona Australis star-forming region in three
separate epochs Results: We report the first firm radio detection of a class I
protostar using very long baseline interferometry. We have detected the
previously known non-thermal source IRS 5b, part of a binary system. IRS 5a and
IRS 5N were undetected, as were all sources in the IRS 7 region. Conclusions:
These results underline the unusual nature of IRS 5b as a genuine protostar
with confirmed non-thermal radio emission. Also, these observations highlight
the potential of the LBA as a tool to provide precision astrometric
measurements of individual young stellar objects in southern star-forming
regions that are not accessible to the Very Long Baseline Array in the northern
hemisphere.


title:
Mean-field granocentric approach in 2D & 3D polydisperse, frictionless
  packings

abstract:
  We have studied the contact network properties of two and three dimensional
polydisperse, frictionless sphere packings at the random closed packing density
through simulations. We observe universal correlations between particle size
and contact number that are independent of the polydispersity of the packing.
This allows us to formulate a mean field version of the granocentric model to
predict the contact number distribution P(z). We find the predictions to be in
good agreement with a wide range of discrete and continuous size distributions.
The values of the two parameters that appear in the model are also independent
of the polydispersity of the packing. Finally we look at the nearest neighbour
spatial correlations to investigate the validity of the granocentric approach.
We find that both particle size and contact number are anti-correlated which
contrasts with the assumptions of the granocentric model. Despite this
shortcoming, the correlations are sufficiently weak which explains the good
approximation of P(z) obtained from the model.


title: Which Boolean Functions are Most Informative?

abstract:
  We introduce a simply stated conjecture regarding the maximum mutual
information a Boolean function can reveal about noisy inputs. Specifically, let
$X^n$ be i.i.d. Bernoulli(1/2), and let $Y^n$ be the result of passing $X^n$
through a memoryless binary symmetric channel with crossover probability
$\alpha$. For any Boolean function $b:\{0,1\}^n\rightarrow \{0,1\}$, we
conjecture that $I(b(X^n);Y^n)\leq 1-H(\alpha)$. While the conjecture remains
open, we provide substantial evidence supporting its validity.


title:
On the structure of the directions not determined by a large affine
  point set

abstract:
  Given a point set $U$ in an $n$-dimensional affine space of size
$q^{n-1}-\varepsilon$, we obtain information on the structure of the set of
directions that are not determined by $U$, and we describe an application in
the theory of partial ovoids of certain partial geometries.


title: The emission measure distribution of impulsive phase flare footpoints

abstract:
  The temperature distribution of the emitting plasma is a crucial constraint
when studying the heating of solar flare footpoints. However, determining this
for impulsive phase footpoints has been difficult in the past due to
insufficient spatial resolution to resolve the footpoints from the loop
structures, and a lack of spectral and temporal coverage. We use the
capabilities of Hinode/EIS to obtain the first emission measure distributions
(EMDs) from impulsive phase footpoints in six flares. Observations with good
spectral coverage were analysed using a regularized inversion method to recover
the EMDs. We find that the EMDs all share a peak temperature of around 8 MK,
with lines formed around this temperature having emission measures peaking
between 10^28 and 10^29 cm^-5, indicating a substantial presence of plasma at
very high temperatures within the footpoints. An EMD gradient of EM(T) ~ T is
found in all events. Previous theoretical work on emission measure gradients
shows this to be consistent with a scenario in which the deposited flare energy
directly heats only the top layer of the flare chromosphere, while deeper
layers are heated by conduction.


title: Systematizing semi-shortening

abstract:
  We re-derive semi-shortening conditions for four-dimensional superconformal
field theory with a different approach. These conditions have similar patterns
that can be generalized to weaker constraints, including all those of F. Dolan
and H. Osborn. In particular, for the case of $\mathcal{N} = 4$ super
Yang-Mills theory, formulated in projective superspace, we find constraints for
all BPS operators. We also give an example how constraints can be found from
known ones. These constraints are a subset of our maximal set of
semi-shortening conditions.


title: A Parallel World in the Dark

abstract:
  The baryon-dark matter coincidence is a long-standing issue. Interestingly,
the recent observations suggest the presence of dark radiation, which, if
confirmed, would pose another coincidence problem of why the density of dark
radiation is comparable to that of photons. These striking coincidences may be
traced back to the dark sector with particle contents and interactions that are
quite similar, if not identical, to the standard model: a dark parallel world.
It naturally solves the coincidence problems of dark matter and dark radiation,
and predicts a sterile neutrino(s) with mass of ${\cal O}(0.1 - 1)$\,eV, as
well as self-interacting dark matter made of the counterpart of ordinary
baryons. We find a robust prediction for the relation between the abundance of
dark radiation and the sterile neutrino, which can serve as the smoking-gun
evidence of the dark parallel world.


title: Quantifying phases in homogenous twisted birefringent medium

abstract:
  The internal birefringence of an optical medium develops the dynamical phase
through natural rotation of incident polarized light. The uniform twist of the
medium induces an external birefringence in the system.This can be visualized
through the geometric phase by the solid angle in association with the angular
twist per unit thickness of the medium $k$.An equivalent physical analysis in
the $l=1$ orbital angular momentum sphere also has been pointed out.


title: Minimum Dominating Sets in Scale-Free Network Ensembles

abstract:
  We study the scaling behavior of the size of minimum dominating set (MDS) in
scale-free networks, with respect to network size $N$ and power-law exponent
$\gamma$, while keeping the average degree fixed. We study ensembles generated
by three different network construction methods, and we use a greedy algorithm
to approximate the MDS. With a structural cutoff imposed on the maximal degree
($k_{\max}=\sqrt{N}$) we find linear scaling of the MDS size with respect to
$N$ in all three network classes. Without any cutoff ($k_{\max}=N-1$) two of
the network classes display a transition at $\gamma \approx 1.9$, with linear
scaling above, and vanishingly weak dependence below, but in the third network
class we find linear scaling irrespective of $\gamma$. We find that the partial
MDS, which dominates a given $z<1$ fraction of nodes, displays essentially the
same scaling behavior as the MDS.


title:
A Generalization of Order Theoretic Properties of the Line and
  Topological Implications

abstract:
  [Note to the reader: properties (C2) and (C2)* are under development, in
order to form a generalization of (C3) and (C3)*]


title: On the splitting of a normalizer of a torus in symplectic groups

abstract:
  In this paper we find all symplectic groups and their maximal tori in which
normalizer of a torus is split over the torus.


title: Analytic theory of optical nano-plasmonic metamaterials

abstract:
  Recent advances in nano-fabrication techniques allow for the manufacture of
optical metamaterials, bringing their unique and extra-ordinary properties to
the visible regime and beyond. However, an analytical description of optical
nano-plasmonic metamaterials is challenging due to the characteristic optical
behaviour of metals. Here we present an analytical theory that allows to bring
established microwave metamaterials models to optical wavelengths. This method
is implemented for nano-scaled plasmonic wire-mesh and tri-helical
metamaterials, and we obtain an accurate prediction for their dispersive
behaviour at optical and near-IR wavelengths.


title: Asymptotic Behavior of an Implicit Algebraic Plane Curve

abstract:
  In this paper, we introduce the notion of infinity branches as well as
approaching curves. We present some properties which allow us to obtain an
algorithm that compares the behavior of two implicitly defined algebraic plane
curves at the infinity. As an important result, we prove that if two plane
algebraic curves have the same asymptotic behavior, the Hausdorff distance
between them is finite.


title: Stability of the toroidal magnetic field in rotating stars

abstract:
  The magnetic field in stellar radiation zones can play an important role in
phenomena such as mixing, angular momentum transport, etc. We study the effect
of rotation on the stability of a predominantly toroidal magnetic field in the
radiation zone. In particular we considered the stability in spherical geometry
by means of a linear analysis in the Boussinesq approximation. It is found that
the effect of rotation on the stability depends on a magnetic configuration. If
the toroidal field increases with the spherical radius, the instability cannot
be suppressed entirely even by a very fast rotation. Rotation can only decrease
the growth rate of instability. If the field decreases with the radius, the
instability has a threshold and can be completey suppressed.


title:
High-order harmonic generation by enhanced plasmonic near-fields in
  metal nanoparticules

abstract:
  We present theoretical investigations of high-order harmonic generation (HHG)
resulting from the interaction of noble gases with localized surface plasmons.
These plasmonic fields are produced when a metal nanoparticle is subject to a
few-cycle laser pulse. The enhanced field, which largely depends on the
geometrical shape of the metallic structure, has a strong spatial dependency.
We demonstrate that the strong non-homogeneity of this laser field plays an
important role in the HHG process and leads to a significant increase of the
harmonic cut-off energy. In order to understand and characterize this new
feature, we include the functional form of the laser electric field obtained
from recent attosecond streaking experiments [F. S{\"u}{\ss}mann and M. F.
Kling, Proc. of SPIE, {\bf Vol. 8096}, 80961C (2011)] in the time dependent
Schr\"odinger equation (TDSE). By performing classical simulations of the HHG
process we show consistency between them and the quantum mechanical
predictions. These allow us to understand the origin of the extended harmonic
spectra as a selection of particular trajectory sets. The use of metal
nanoparticles shall pave a completely new way of generating coherent XUV light
with a laser field which characteristics can be synthesized locally.


title: Foundations of Descriptive and Inferential Statistics

abstract:
  These lecture notes were written with the aim to provide an accessible though
technically solid introduction to the logic of systematical analyses of
statistical data to both undergraduate and postgraduate students, in particular
in the Social Sciences, Economics, and the Financial Services. They may also
serve as a general reference for the application of quantitative--empirical
research methods. In an attempt to encourage the adoption of an
interdisciplinary perspective on quantitative problems arising in practice, the
notes cover the four broad topics (i) descriptive statistical processing of raw
data, (ii) elementary probability theory, (iii) the operationalisation of
one-dimensional latent statistical variables according to Likert's widely used
scaling approach, and (iv) null hypothesis significance testing within the
frequentist approach to probability theory concerning (a) distributional
differences of variables between subgroups of a target population, and (b)
statistical associations between two variables. The relevance of effect sizes
for making inferences is emphasised. These lecture notes are fully hyperlinked,
thus providing a direct route to original scientific papers as well as to
interesting biographical information. They also list many commands for running
statistical functions and data analysis routines in the software packages R,
SPSS, EXCEL and OpenOffice. The immediate involvement in actual data analysis
practices is strongly recommended.


title:
On stability of collisional coupling between relativistic electrons and
  ions in hot plasmas

abstract:
  The collisional coupling of relativistic electrons and non-relativistic ions
in hot plasmas has been analysed. It is found that relativistic effects produce
a new feature: while the condition T_e<3T_i guarantees a stable collisional
coupling between electrons and ions in low-temperature plasmas, relativistic
effects shift the upper T_e/T_i boundary of stability to higher values.
Moreover, for sufficiently high temperatures, T_{e,i} > 75 keV, collisional
decoupling between relativistic electrons and ions becomes impossible.


title: The Tsallis-Laplace Transform

abstract:
  We introduce here the q-Laplace transform as a new weapon in Tsallis'
arsenal, discussing its main properties and analyzing some examples. The
q-Gaussian instance receives special consideration. Also, we derive the
q-partition function from the q-Laplace transform.


title:
Automorphisms of Curves and Weierstrass semigroups for
  Harbater-Katz-Gabber covers

abstract:
  We study $p$-group Galois covers $X \rightarrow \mathbb{P}^1$ with only one
fully ramified point. These covers are important because of the Katz-Gabber
compactification of Galois actions on complete local rings. The sequence of
ramification jumps is related to the Weierstrass semigroup of the global cover
at the stabilized point. We determine explicitly the jumps of the ramification
filtrations in terms of pole numbers. We give applications for curves with zero
$p$--rank: we focus on maximal curves and curves that admit a big action.
  Moreover the Galois module structure of polydifferentials is studied and an
application to the tangent space of the deformation functor of curves with
automorphisms is given.


title:
VM-MAD: a cloud/cluster software for service-oriented academic
  environments

abstract:
  The availability of powerful computing hardware in IaaS clouds makes cloud
computing attractive also for computational workloads that were up to now
almost exclusively run on HPC clusters.
  In this paper we present the VM-MAD Orchestrator software: an open source
framework for cloudbursting Linux-based HPC clusters into IaaS clouds but also
computational grids. The Orchestrator is completely modular, allowing flexible
configurations of cloudbursting policies. It can be used with any batch system
or cloud infrastructure, dynamically extending the cluster when needed. A
distinctive feature of our framework is that the policies can be tested and
tuned in a simulation mode based on historical or synthetic cluster accounting
data.
  In the paper we also describe how the VM-MAD Orchestrator was used in a
production environment at the FGCZ to speed up the analysis of mass
spectrometry-based protein data by cloudbursting to the Amazon EC2. The
advantages of this hybrid system are shown with a large evaluation run using
about hundred large EC2 nodes.


title:
Polarization morphology of SiO masers in the circumstellar envelope of
  the AGB star R Cassiopeiae

abstract:
  Silicon monoxide maser emission has been detected in the circumstellar
envelopes of many evolved stars in various vibrationally-excited rotational
transitions. It is considered a good tracer of the wind dynamics close to the
photosphere of the star. We have investigated the polarization morphology in
the circumstellar envelope of an AGB star, R Cas. We mapped the linear and
circular polarization of SiO masers in the v=1, J=1-0 transition. The linear
polarization is typically a few tens of percent while the circular polarization
is a few percent. The fractional polarization tends to be higher for emission
of lower total intensity. We found that, in some isolated features the
fractional linear polarization appears to exceed 100%. We found the Faraday
rotation is not negligible but is ~15 deg., which could produce small scale
structure in polarized emission whilst total intensity is smoother and partly
resolved out. The polarization angles vary considerably from feature to feature
but there is a tendency to favour the directions parallel or perpendicular to
the radial direction with respect to the star. In some features, the
polarization angle abruptly flips 90 deg. We found that our data are in the
regime where the model of Goldreich et al (1973) can be applied and the
polarization angle flip is caused when the magnetic field is at close to 55
deg. to the line of sight. The polarization angle configuration is consistent
with a radial magnetic field although other configurations are not excluded.


title: Physical Brownian motion in magnetic field as rough path

abstract:
  The indefinite integral of the homogenized Ornstein-Uhlenbeck process is a
well-known model for physical Brownian motion, modelling the behaviour of an
object subject to random impulses [L. S. Ornstein, G. E. Uhlenbeck: On the
theory of Brownian Motion. In: Physical Review. 36, 1930, 823-841]. One can
scale these models by changing the mass of the particle and in the small mass
limit one has almost sure uniform convergence in distribution to the standard
idealized model of mathematical Brownian motion. This provides one well known
way of realising the Wiener process. However, this result is less robust than
it would appear and important generic functionals of the trajectories of the
physical Brownian motion do not necessarily converge to the same functionals of
Brownian motion when one takes the small mass limit. In presence of a magnetic
field the area process associated to the physical process converges - but not
to L\'evy's stochastic area. As this area is felt generically in settings where
the particle interacts through force fields in a nonlinear way, the remark is
physically significant and indicates that classical Brownian motion, with its
usual stochastic calculus, is not an appropriate model for the limiting
behaviour.
  We compute explicitly the area correction term and establish convergence, in
the small mass limit, of the physical Brownian motion in the rough path sense.
The small mass limit for the motion of a charged particle in the presence of a
magnetic field is, in distribution, an easily calculable, but "non-canonical"
rough path lift of Brownian motion. Viewing the trajectory of a charged
Brownian particle with small mass as a rough path is informative and allows one
to retain information that would be lost if one only considered it as a
classical trajectory. We comment on the importance of this point of view.


title:
Exact and approximate solutions to Schroedinger's equation with decatic
  potentials

abstract:
  The one-dimensional Schroedinger's equation is analysed with regard to the
existence of exact solutions for decatic polynomial potentials. Under certain
conditions on the potential's parameters, we show that the decatic polynomial
potential $V(x)=ax^{10}+bx^8+cx^6+dx^4+ex^2$, $a>0$ is exactly solvable. By
examining the polynomial solutions of certain linear differential equations
with polynomial coefficients, the necessary and sufficient conditions for
corresponding energy-dependent polynomial solutions are given in detail. It is
also shown that these polynomials satisfy a four-term recurrence relation,
whose real roots are the exact energy eigenvalues. Further, it is shown that
these polynomials generate the eigenfunction solutions of the corresponding
Schroedinger equation. Further analysis for arbitrary values of the potential
parameters using the asymptotic iteration method is also presented.


title: Time-Symmetry Breaking in Hamiltonian Mechanics

abstract:
  Hamiltonian trajectories are strictly time-reversible. Any time series of
Hamiltonian coordinates {q} satisfying Hamilton's motion equations will
likewise satisfy them when played "backwards", with the corresponding momenta
changing signs : {+p} --> {-p}. Here we adopt Levesque and Verlet's precisely
bit-reversible motion algorithm to ensure that the trajectory reversibility is
exact, with the forward and backward sets of coordinates identical.
Nevertheless, the associated instantaneous Lyapunov instability, or "sensitive
dependence on initial conditions" of "chaotic" (or "Lyapunov unstable")
bit-reversible coordinate trajectories can still exhibit an exponentially
growing time-symmetry-breaking irreversibility. Surprisingly, the positive and
negative exponents, as well as the forward and backward Lyapunov spectra, are
usually not closely related, and so give four differing topological measures of
"local" chaos. We have demonstrated this symmetry breaking for fluid
shockwaves, for free expansions, and for chaotic molecular collisions. Here we
illustrate and discuss this time-symmetry breaking for three
statistical-mechanical systems, [1] a minimal (but still chaotic) one-body
"cell model" with a four-dimensional phase space; [2] relatively small
colliding crystallites, for which the whole Lyapunov spectrum is accessible;
[3] a near-continuum inelastic collision of two larger 400-particle balls. In
the last two of these pedagogical problems the two colliding bodies coalesce.
The particles most prone to Lyapunov instability are dramatically different in
the two time directions. Thus this Lyapunov-based symmetry breaking furnishes
an interesting Arrow of Time.

categories: cond-mat.stat-mech math-ph math.MP nlin.CD


title: Stationarity and ergodicity for an affine two factor model

abstract:
  We study the existence of a unique stationary distribution and ergodicity for
a 2-dimensional affine process. The first coordinate is supposed to be a
so-called alpha-root process with \alpha\in(1,2]. The existence of a unique
stationary distribution for the affine process is proved in case of
\alpha\in(1,2]; further, in case of \alpha=2, the ergodicity is also shown.


title:
Norm continuous unitary representations of Lie algebras of smooth
  sections

abstract:
  We give a complete description of the bounded (i.e. norm continuous) unitary
representations of the Fr\'echet-Lie algebra of all smooth sections, as well as
of the LF-Lie algebra of compactly supported smooth sections, of a smooth Lie
algebra bundle whose typical fiber is a compact Lie algebra. For the Lie
algebra of all sections, bounded unitary irreducible representations are finite
tensor products of so-called evaluation representations, hence in particular
finite-dimensional. For the Lie algebra of compactly supported sections,
bounded unitary irreducible (factor) representations are possibly infinite
tensor products of evaluation representations, which reduces the classification
problem to results of Glimm and Powers on irreducible (factor) representations
of UHF C*-algebras. The key part in our proof is the classification of
irreducible bounded unitary representations of Lie algebras that are the tensor
product of a compact Lie algebra and a unital real continuous inverse algebra:
every such representation is a finite product of evaluation representations. On
the group level, our results cover in particular the bounded unitary
representations of the identity component of the group of smooth gauge
transformations of a principal fiber bundle with compact base and structure
group, and the connected component of the group of special unitary n times n
matrices with values in an involutive commutative continuous inverse algebra.


title: Lyapunov Exponent and Charged Myers Perry Spacetimes

abstract:
  We compute the proper time Lyapunov exponent for charged Myers Perry black
hole spacetime and investigate the instability of the equatorial circular
geodesics (both timelike and null) via this exponent. We also show that for
more than four spacetime dimensions $(N \geq 3)$, there are \emph{no} Innermost
Stable Circular Orbits (ISCOs) in charged Myers Perry black hole spacetime. We
further show that among all possible circular orbits, timelike circular orbits
have \emph{longer} orbital periods than null circular orbits (photon spheres)
as measured by asymptotic observers. Thus, timelike circular orbits provide the
\emph{slowest way} to orbit around the charged Myers Perry black hole.

categories: gr-qc astro-ph.HE math-ph math.MP nlin.CD


title: Preliminary Energy Considerations in a Relativistic Engine

abstract:
  In a previous paper \cite{MTAY1} we have shown that Newton'n third law cannot
strictly hold in a distributed system of which the different parts are at a
finite distance from each other. This is due to the finite speed of signal
propagation which cannot exceed the speed of light at vacuum, which in turn
means that when summing the total force in the system the force does not add up
to zero. This was demonstrated in a specific example of two current loops with
time dependent currents, the above analysis led to suggestion of a relativistic
engine \cite{MTAY3,AY1}. Since the system is effected by a total force for a
finite period of time this means that the system acquires mechanical momentum
and energy, the question then arises if we need to abandon the law of momentum
and energy conservation. The subject of momentum conversation was discussed in
\cite{MTAY4}. Here some preliminary aspects of the exchange of energy between
the mechanical part of the relativistic engine and the electromagnetic field
are discussed. We also refer briefly to the material composition, structure and
properties of metals that should be used in a relativistic engine.


title: ATLASGAL --- Environments of 6.7\,GHz methanol masers

abstract:
  Using the 870-$\mu$m APEX Telescope Large Area Survey of the Galaxy
(ATLASGAL), we have identified 577 submillimetre continuum sources with masers
from the methanol multibeam (MMB) survey in the region $280\degr < \ell <
20\degr$; $|\,b\,| < 1.5\degr$. 94\,per\,cent of methanol masers in the region
are associated with sub-millimetre dust emission. We estimate masses for ~450
maser-associated sources and find that methanol masers are preferentially
associated with massive clumps. These clumps are centrally condensed, with
envelope structures that appear to be scale-free, the mean maser position being
offset from the peak column density by 0.0 \pm 4". Assuming a Kroupa initial
mass function and a star-formation efficiency of ~30\,per\,cent, we find that
over two thirds of the clumps are likely to form clusters with masses
>20\,\msun. Furthermore, almost all clumps satisfy the empirical mass-size
criterion for massive star formation. Bolometric luminosities taken from the
literature for ~100 clumps range between ~100 and 10$^6$\,\lsun. This confirms
the link between methanol masers and massive young stars for 90\,per\,cent of
our sample. The Galactic distribution of sources suggests that the
star-formation efficiency is significantly reduced in the Galactic-centre
region, compared to the rest of the survey area, where it is broadly constant,
and shows a significant drop in the massive star-formation rate density in the
outer Galaxy. We find no enhancement in source counts towards the southern
Scutum-Centaurus arm tangent at $\ell ~ 315\degr$, which suggests that this arm
is not actively forming stars.


title:
Splitting of photo-luminescent emission from nitrogen-vacancy centers in
  diamond induced by ion-damage-induced stress

abstract:
  We report a systematic investigation on the spectral splitting of negatively
charged, nitrogen-vacancy (NV-) photo-luminescent emission in single crystal
diamond induced by strain engineering. The stress fields arise from MeV
ion-induced conversion of diamond to amorphous and graphitic material in
regions proximal to the centers of interest. In low-nitrogen sectors of a HPHT
diamond, clearly distinguishable spectral components in the NV- emission
develop over a range of 4.8 THz corresponding to distinct alignment of
sub-ensembles which were mapped with micron spatial resolution. This method
provides opportunities for the creation and selection of aligned NV- centers
for ensemble quantum information protocols.


title: Composite Fermions with Tunable Fermi Contour Anisotropy

abstract:
  The composite fermion formalism elegantly describes some of the most
fascinating behaviours of interacting two-dimensional carriers at low
temperatures and in strong perpendicular magnetic fields. In this framework,
carriers minimize their energy by attaching two flux quanta and forming new
quasi-particles, the so-called composite fermions. Thanks to the flux
attachment, when a Landau level is half-filled, the composite fermions feel a
vanishing effective magnetic field and possess a Fermi surface with a
well-defined Fermi contour. Our measurements in a high-quality two-dimensional
hole system confined to a GaAs quantum well demonstrate that a parallel
magnetic field can significantly distort the hole-flux composite fermion Fermi
contour.


title: Totally Real Mappings and Independent Mappings

abstract:
  We consider two classes of smooth maps M^n\to C ^N. Definition. A map
f:M^n\to C^N is called an independent map if df_1(p)\wedge...\wedge df_N
(p)\neq 0. We are interested in the optimal value of N for all manifolds of
dimension n for independent maps and also for totally real immersions.


title: A-STAR: The All-Sky Transient Astrophysics Reporter

abstract:
  The small mission A-STAR (All-Sky Transient Astrophysics Reporter) aims to
locate the X-ray counterparts to ALIGO and other gravitational wave detector
sources, to study the poorly-understood low luminosity gamma-ray bursts, and to
find a wide variety of transient high-energy source types, A-STAR will survey
the entire available sky twice per 24 hours. The payload consists of a coded
mask instrument, Owl, operating in the novel low energy band 4-150 keV, and a
sensitive wide-field focussing soft X-ray instrument, Lobster, working over
0.15-5 keV. A-STAR will trigger on ~100 GRBs/yr, rapidly distributing their
locations.


title: Byzantine Vector Consensus in Complete Graphs

abstract:
  Consider a network of n processes each of which has a d-dimensional vector of
reals as its input. Each process can communicate directly with all the
processes in the system; thus the communication network is a complete graph.
All the communication channels are reliable and FIFO (first-in-first-out). The
problem of Byzantine vector consensus (BVC) requires agreement on a
d-dimensional vector that is in the convex hull of the d-dimensional input
vectors at the non-faulty processes. We obtain the following results for
Byzantine vector consensus in complete graphs while tolerating up to f
Byzantine failures:
  * We prove that in a synchronous system, n >= max(3f+1, (d+1)f+1) is
necessary and sufficient for achieving Byzantine vector consensus.
  * In an asynchronous system, it is known that exact consensus is impossible
in presence of faulty processes. For an asynchronous system, we prove that n >=
(d+2)f+1 is necessary and sufficient to achieve approximate Byzantine vector
consensus.
  Our sufficiency proofs are constructive. We show sufficiency by providing
explicit algorithms that solve exact BVC in synchronous systems, and
approximate BVC in asynchronous systems.
  We also obtain tight bounds on the number of processes for achieving BVC
using algorithms that are restricted to a simpler communication pattern.


title:
Quality Control and Due Diligence in Project Management: Getting
  Decisions Right by Taking the Outside View

abstract:
  This paper explores how theories of the planning fallacy and the outside view
may be used to conduct quality control and due diligence in project management.
First, a much-neglected issue in project management is identified, namely that
the front-end estimates of costs and benefits--used in the business cases,
cost-benefit analyses, and social and environmental impact assessments that
typically support decisions on projects--are typically significantly different
from actual ex post costs and benefits, and are therefore poor predictors of
the actual value and viability of projects. Second, it is discussed how
Kahneman and Tversky's theories of the planning fallacy and the outside view
may help explain and remedy this situation through quality control of
decisions. Third, it is described what quality control and due diligence are in
the context of project management, and an eight-step procedure is outlined for
due diligence based on the outside view. Fourth, the procedure is tested on a
real-life, multibillion-dollar project, organized as a public-private
partnership. Finally, Akerlof and Shiller's recent discussion in economics of
"firing the forecaster" is discussed together with its relevance to project
management. In sum, the paper demonstrates the need, the theoretical basis, a
practical methodology, and a real-life example for how to de-bias project
management using quality control and due diligence based on the outside view.


title: Rindler type acceleration in f(R) gravity

abstract:
  By choosing a fluid source in $f(R)$ gravity, defined by $f\left(R\right)
=R-12a\xi \ln \left\ | R\right\ | $, where $a$ (=Rindler acceleration) and $\xi
$ are both constants, the field equations correctly yield the Rindler
acceleration term in the metric. We identify domains in which the weak energy
conditions (WEC) and the strong energy conditions (SEC) are satisfied.


title:
Coronal Mass Ejections As a Mechanism for Producing IR Variability in
  Debris Disks

abstract:
  Motivated by recent observations of short-timescale variations in the
infrared emission of circumstellar disks, we propose that coronal mass
ejections can remove dust grains on timescales as short as a few days.
Continuous monitoring of stellar activity, coupled to infrared observations,
can place meaningful constraints on the proposed mechanism.


title: Parallel Unsmoothed Aggregation Algebraic Multigrid Algorithms on GPUs

abstract:
  We design and implement a parallel algebraic multigrid method for isotropic
graph Laplacian problems on multicore Graphical Processing Units (GPUs). The
proposed AMG method is based on the aggregation framework. The setup phase of
the algorithm uses a parallel maximal independent set algorithm in forming
aggregates and the resulting coarse level hierarchy is then used in a K-cycle
iteration solve phase with a $\ell^1$-Jacobi smoother. Numerical tests of a
parallel implementation of the method for graphics processors are presented to
demonstrate its effectiveness.


title: Anomalous decay of quantum correlations of quantum dot qubits

abstract:
  We study the evolution of quantum correlations, quantified by the geometric
discord, of two excitonic quantum dot qubits under the influence of the phonon
environment. We show that the decay of these correlations differs substantially
form the decay of entanglement. Instead of displaying sudden death type
behavior, the geometric discord shows a tendency to undergo transitions between
different types of decay, is sensitive to non-local phase factors, and may
already be enhanced by weak environment-mediated interactions. Hence, two-qubit
quantum correlations are more robust under decoherence processes, while showing
a richer and more complex spectrum of behavior under unitary and non-unitary
evolution.


title: Stellar Encounter Rate in Galactic Globular Clusters

abstract:
  The high stellar densities in the cores of globular clusters cause
significant stellar interactions. These stellar interactions can produce close
binary mass-transferring systems involving compact objects and their progeny,
such as X-ray binaries and radio millisecond pulsars. Comparing the numbers of
these systems and interaction rates in different clusters drives our
understanding of how cluster parameters affect the production of close
binaries. In this paper we estimate stellar encounter rates (Gamma) for 124
Galactic globular clusters based on observational data as opposed to the
methods previously employed, which assumed "King-model" profiles for all
clusters. By deprojecting cluster surface brightness profiles to estimate
luminosity density profiles, we treat "King-model" and "core-collapsed"
clusters in the same way. In addition, we use Monte-Carlo simulations to
investigate the effects of uncertainties in various observational parameters
(distance, reddening, surface brightness) on Gamma, producing the first catalog
of GC stellar encounter rates with estimated errors. Comparing our results with
published observations of likely products of stellar interactions (numbers of
X-ray binaries, numbers of radio millisecond pulsars, and gamma-ray luminosity)
we find both clear correlations and some differences with published results.


title: Online Regret Bounds for Undiscounted Continuous Reinforcement Learning

abstract:
  We derive sublinear regret bounds for undiscounted reinforcement learning in
continuous state space. The proposed algorithm combines state aggregation with
the use of upper confidence bounds for implementing optimism in the face of
uncertainty. Beside the existence of an optimal policy which satisfies the
Poisson equation, the only assumptions made are Holder continuity of rewards
and transition probabilities.


title:
No-Wait Flowshop Scheduling is as Hard as Asymmetric Traveling Salesman
  Problem

abstract:
  In this paper we study the classical no-wait flowshop scheduling problem with
makespan objective (F|no-wait|C_max in the standard three-field notation). This
problem is well-known to be a special case of the asymmetric traveling salesman
problem (ATSP) and as such has an approximation algorithm with logarithmic
performance guarantee. In this work we show a reverse connection, we show that
any polynomial time \alpha-approximation algorithm for the no-wait flowshop
scheduling problem with makespan objective implies the existence of a
polynomial-time \alpha(1+\epsilon)-approximation algorithm for the ATSP, for
any \epsilon>0. This in turn implies that all non-approximability results for
the ATSP (current or future) will carry over to its special case. In
particular, it follows that no-wait flowshop problem is APX-hard, which is the
first non-approximability result for this problem.


title: Selecting the State-Representation in Reinforcement Learning

abstract:
  The problem of selecting the right state-representation in a reinforcement
learning problem is considered. Several models (functions mapping past
observations to a finite set) of the observations are given, and it is known
that for at least one of these models the resulting state dynamics are indeed
Markovian. Without knowing neither which of the models is the correct one, nor
what are the probabilistic characteristics of the resulting MDP, it is required
to obtain as much reward as the optimal policy for the correct model (or for
the best of the correct models, if there are several). We propose an algorithm
that achieves that, with a regret of order T^{2/3} where T is the horizon time.


title:
Optimal Regret Bounds for Selecting the State Representation in
  Reinforcement Learning

abstract:
  We consider an agent interacting with an environment in a single stream of
actions, observations, and rewards, with no reset. This process is not assumed
to be a Markov Decision Process (MDP). Rather, the agent has several
representations (mapping histories of past interactions to a discrete state
space) of the environment with unknown dynamics, only some of which result in
an MDP. The goal is to minimize the average regret criterion against an agent
who knows an MDP representation giving the highest optimal reward, and acts
optimally in it. Recent regret bounds for this setting are of order
$O(T^{2/3})$ with an additive term constant yet exponential in some
characteristics of the optimal MDP. We propose an algorithm whose regret after
$T$ time steps is $O(\sqrt{T})$, with all constants reasonably small. This is
optimal in $T$ since $O(\sqrt{T})$ is the optimal regret in the setting of
learning in a (single discrete) MDP.


title: GSE statistics without spin

abstract:
  Energy levels statistics following the Gaussian Symplectic Ensemble (GSE) of
Random Matrix Theory have been predicted theoretically and observed numerically
in numerous quantum chaotic systems. However in all these systems there has
been one unifying feature: the combination of half-integer spin and
time-reversal invariance. Here we provide an alternative mechanism for
obtaining GSE statistics that is based on geometric symmetries of a quantum
system which alleviates the need for spin. As an example, we construct a
quantum graph with a particular discrete symmetry given by the quaternion group
Q8. GSE statistics is then observed within one of its subspectra.


title: Avoider-Enforcer star games

abstract:
  In this paper, we study $(1 : b)$ Avoider-Enforcer games played on the edge
set of the complete graph on $n$ vertices. For every constant $k\geq 3$ we
analyse the $k$-star game, where Avoider tries to avoid claiming $k$ edges
incident to the same vertex. We analyse both versions of Avoider-Enforcer games
-- the strict and the monotone -- and for each provide explicit winning
strategies for both players. We determine the order of magnitude of the
threshold biases $f^{mon}_\mathcal{F}$, $f^-_\mathcal{F}$ and
$f^+_\mathcal{F}$, where $\mathcal{F}$ is the hypergraph of the game.


title:
Intersection Cuts for Nonlinear Integer Programming: Convexification
  Techniques for Structured Sets

abstract:
  We study the generalization of split, k-branch split, and intersection cuts
from Mixed Integer Linear Programming to the realm of Mixed Integer Nonlinear
Programming. Constructing such cuts requires calculating the convex hull of the
difference between a convex set and an open set with a simple geometric
structure. We introduce two techniques to give precise characterizations of
such convex hulls and use them to construct split, k-branch split, and
intersection cuts for several classes of non-polyhedral sets. In particular, we
give simple formulas for split cuts for essentially all convex sets described
by a single quadratic inequality. We also give simple formulas for k-branch
split cuts and some general intersection cuts for a wide variety of convex
quadratic sets.


title:
Stationary bound states of spin-half particles in the
  Reissner-Nordstroem gravitational field

abstract:
  We prove the possibility of existence of stationary bound states of spin-half
particles in the Reissner-Nordstroem gravitational field using a self-conjugate
Hamiltonian with a flat scalar product of wave functions. Bound states of Dirac
particles with a real discrete energy spectrum can exist both for particles
above the external "event horizon", and for particles under the internal "event
horizon", or the Cauchy horizon. The Hilbert condition g_{00}>0 leads to a
boundary condition such that components of the vector of current density of
Dirac particles are zero near the "event horizons". Based on the results of
this study, we can assume that there exists a new type of charged collapsars,
for which the Hawking radiation is not present. The results of this study can
lead to a revision of some concepts of the standard cosmological model related
to the evolution of the universe and interaction of charged collapsars with
surrounding matter.


title:
Proper motions and membership probabilities of stars in the region of
  open cluster NGC 3766

abstract:
  Relative proper motions and cluster membership probabilities have been
derived for ~ 2500 stars in the field of the open star cluster NGC 3766. The
cluster has been observed in $B$ and $V$ broadband filters at two epochs
separated by ~ 6 years using a wide-field imager mounted on the WFI@ESO2.2m
telescope. All CCD frames were reduced using the astrometric techniques
described in Anderson et al. (2006). The proper motion r.m.s. error for stars
brighter than $V$ ~ 15 mag is 2.0 mas/yr but it gradually increases up to ~4
mas/yr at $V$ ~20 mag. Using proper motion data, membership probabilities have
been derived for the stars in the region of the cluster. They indicate that
three Be and one Ap stars are member of the cluster. The reddening
$E(B-V)=0.22\pm0.05$ mag, a distance 2.5$\pm$0.5 kpc and an age of ~ 20 Myr are
derived using stars of $P_{\mu}>70%$. Mass function slope $x=1.60\pm0.10$ is
derived for the cluster and cluster was found to be dynamically relaxed.
Finally, we provide positions, calibrated $B$ and $V$ magnitudes, relative
proper motions and membership probabilities for the stars in the field of NGC
3766. We have produced a catalog that is electronically available to the
astronomical community.


title:
Alternating proximal gradient method for sparse nonnegative Tucker
  decomposition

abstract:
  Multi-way data arises in many applications such as electroencephalography
(EEG) classification, face recognition, text mining and hyperspectral data
analysis. Tensor decomposition has been commonly used to find the hidden
factors and elicit the intrinsic structures of the multi-way data. This paper
considers sparse nonnegative Tucker decomposition (NTD), which is to decompose
a given tensor into the product of a core tensor and several factor matrices
with sparsity and nonnegativity constraints. An alternating proximal gradient
method (APG) is applied to solve the problem. The algorithm is then modified to
sparse NTD with missing values. Per-iteration cost of the algorithm is
estimated scalable about the data size, and global convergence is established
under fairly loose conditions. Numerical experiments on both synthetic and real
world data demonstrate its superiority over a few state-of-the-art methods for
(sparse) NTD from partial and/or full observations. The MATLAB code along with
demos are accessible from the author's homepage.


title:
Hamiltonian dynamics of several rigid bodies interacting with point
  vortices

abstract:
  We derive the dynamics of several rigid bodies of arbitrary shape in a
2-dimensional inviscid and incompressible fluid, whose vorticity field is given
by point vortices. We adopt the idea of Vankerschaver et al. (2009) to derive
the Hamiltonian formulation via symplectic reduction from a canonical
Hamiltonian system. The reduced system is described by a non-canonical
symplectic form, which has previously been derived for a single, circular disk
using heavy differential-geometric machinery in an infinite-dimensional
setting. In contrast, our derivation makes use of the fact that the dynamics of
the fluid, and thus the point vortex dynamics, is determined from first
principles. Using this knowledge we can directly determine the dynamics on the
reduced, finite-dimensional phase space, using only classical mechanics.
Furthermore, our approach easily handles several bodies of arbitrary shapes.
From the Hamiltonian description we derive a Lagrangian formulation, which
enables the system for variational time integrators. We briefly describe how to
implement such a numerical scheme and simulate different configurations for
validation.


title:
An Explanation of the Differences in Diffusivity of the Components of
  the Metallic Glass Pd43Cu27Ni10P20

abstract:
  Bartsch et al. [A. Bartsch, K. Raetzke, A. Meyer, and F. Faupel, Phys. Rev.
Lett. 104, 195901 (2010)] reported measurements of the diffusivities of
different components of the multi-component bulk metallic glass
Pd43Cu27Ni10P20. The diffusion of the largest Pd and the smallest P were found
to be drastically different. The Stokes-Einstein relation breaks down when
considering the P constituent atom, while the relation is obeyed by the Pd atom
over 14 orders of magnitude of change in Pd diffusivity. This difference in
behavior of Pd and P poses a problem challenging for explanation. With the
assist of a recent finding in metallic glasses that the beta-relaxation and the
diffusion of the smallest component are closely related processes by Yu et al.
[H. B. Yu, K. Samwer, Y. Wu, and W. H. Wang, Phys. Rev. Lett. 109, 095508
(2012)], we use the Coupling Model (CM) to explain the observed difference
between P and Pd quantitatively. The same model also explains the correlation
between property of the beta-relaxation with fragility found in the family of
(CexLa1-x)68Al10Cu20Co2.


title:
Efficient satellite quenching at z~1 from the GEEC2 spectroscopic survey
  of galaxy groups

abstract:
  We present deep GMOS-S spectroscopy for 11 galaxy groups at 0.8<z<1.0, for
galaxies with r_{AB}<24.75. Our sample is highly complete (>66%) for eight of
the eleven groups. Using an optical-NIR colour-colour diagram, the galaxies in
the sample were separated with a dust insensitive method into three categories:
passive (red), star-forming (blue), and intermediate (green). The strongest
environmental dependence is observed in the fraction of passive galaxies, which
make up only ~20 per cent of the field in the mass range
10^{10.3}<M_{star}/M_\odot<10^{11.0} but are the dominant component of groups.
If we assume that the properties of the field are similar to those of the
`pre-accreted' population, the environment quenching efficiency (\epsilon_\rho)
is defined as the fraction of field galaxies required to be quenched in order
to match the observed red fraction inside groups. The efficiency obtained is
~0.4, similar to its value in intermediate-density environments locally. While
green (intermediate) galaxies represent ~20 per cent of the star-forming
population in both the group and field, at all stellar masses, the average sSFR
of the group population is lower by a factor of ~3. The green population does
not show strong H-delta absorption that is characteristic of starburst
galaxies. Finally, the high fraction of passive galaxies in groups, when
combined with satellite accretion models, require that most accreted galaxies
have been affected by their environment. Thus, any delay between accretion and
the onset of truncation of star formation (\tau) must be <2 Gyr, shorter than
the 3-7 Gyr required to fit data at z=0. The relatively small fraction of
intermediate galaxies requires that the actual quenching process occurs
quickly, with an exponential decay timescale of \tau_q<1 Gyr.


title:
Temporal motifs reveal homophily, gender-specific patterns and group
  talk in mobile communication networks

abstract:
  Electronic communication records provide detailed information about temporal
aspects of human interaction. Previous studies have shown that individuals'
communication patterns have complex temporal structure, and that this structure
has system-wide effects. In this paper we use mobile phone records to show that
interaction patterns involving multiple individuals have non-trivial temporal
structure that cannot be deduced from a network presentation where only
interaction frequencies are taken into account. We apply a recently introduced
method, temporal motifs, to identify interaction patterns in a temporal network
where nodes have additional attributes such as gender and age. We then develop
a null model that allows identifying differences between various types of nodes
so that these differences are independent of the network based on interaction
frequencies. We find gender-related differences in communication patters, and
show the existence of temporal homophily, the tendency of similar individuals
to participate in interaction patterns beyond what would be expected on the
basis of the network structure alone. We also show that temporal patterns
differ between dense and sparse parts of the network. Because this result is
independent of edge weights, it can be considered as an extension of
Granovetter's hypothesis to temporal networks.


title:
Influence of internal structure on the motion of test bodies in extreme
  mass ratio situations (MG13)

abstract:
  We present some recent results on the motion of test bodies with internal
structure in General Relativity. On the basis of a multipolar approximation
scheme, we study the motion of extended test bodies endowed with an explicit
model for the quadrupole. The model is inspired by effective actions recently
proposed in the context of the post-Newtonian approximation, including
spin-squared and tidal contributions. In the equatorial plane of the Kerr
geometry, the motion can be characterized by an effective potential of the
binding energy. We compare our findings to recent results for the conservative
part of the self-force in astrophysically realistic situations.


title: On solvability and integrability of the Rabi model

abstract:
  Quasi-exactly solvable Rabi model is investigated within the framework of the
Bargmann Hilbert space of analytic functions ${\cal B}$. On applying the theory
of orthogonal polynomials, the eigenvalue equation and eigenfunctions are shown
to be determined in terms of three systems of monic orthogonal polynomials. The
formal Schweber quantization criterion for an energy variable $x$, originally
expressed in terms of infinite continued fractions, can be recast in terms of a
meromorphic function $F(z) = a_0 + \sum_{k=1}^\infty {\cal M}_k/(z-\xi_k)$ in
the complex plane $\mathbb{C}$ with {\em real simple} poles $\xi_k$ and {\em
positive} residues ${\cal M}_k$. The zeros of $F(x)$ on the real axis determine
the spectrum of the Rabi model. One obtains at once that, on the real axis, (i)
$F(x)$ monotonically decreases from $+\infty$ to $-\infty$ between any two of
its subsequent poles $\xi_k$ and $\xi_{k+1}$, (ii) there is exactly one zero of
$F(x)$ for $x\in (\xi_k,\xi_{k+1})$, and (iii) the spectrum corresponding to
the zeros of $F(x)$ does not have any accumulation point. Additionally, one can
provide much simpler proof of that the spectrum in each parity eigenspace
${\cal B}_\pm$ is necessarily {\em nondegenerate}. Thereby the calculation of
spectra is greatly facilitated. Our results allow us to critically examine
recent claims regarding solvability and integrability of the Rabi model.

categories: quant-ph cond-mat.mes-hall math-ph math.MP


title:
Origin of Ultrafast Ag Radiotracer Diffusion in Shear Bands of Deformed
  Bulk Metallic Glass Pd40Ni40P20

abstract:
  Measurements of Ag radiotracer diffusion in shear bands of deformed bulk
metallic glass, Pd40Ni40P20, [Joachim Bokeloh, Sergiy V. Divinski, Gerrit
Reglitz, and Gerhard Wilde, Phys. Rev. Lett. 107, 235503 (2011).] have found a
colossal enhancement of diffusion coefficient by more than eight orders of
magnitude than in undeformed Pd40Ni40P20. Suggestion was made by Bokeloh et al.
that enhanced diffusion occurs in high-mobility pathways originating from some
excess free volume distribution inside the shear bands. Although plausible,
this qualitative suggestion does not allow quantitative calculation of the
enhancement. The impasse is avoided by using the Coupling Model to calculate
the maximum of the enhancement of diffusivity possible in high-mobility
pathways of the shear bands. Within the range of eight to ten orders of
magnitude, the calculated maximum enhancement is capable to account for the
experimental observation.


title: Technical report : Risk-neutral density recovery via spectral analysis

abstract:
  In this paper, we propose a new method for estimating the conditional
risk-neutral density (RND) directly from a cross-section of put option bid-ask
quotes. More precisely, we propose to view the RND recovery problem as an
inverse problem. We first show that it is possible to define restricted put and
call operators that admit a singular value decomposition (SVD), which we
compute explicitly. We subsequently show that this new framework allows us to
devise a simple and fast quadratic programming method to recover the smoothest
RND whose corresponding put prices lie inside the bid-ask quotes. This method
is termed the spectral recovery method (SRM). Interestingly, the SVD of the
restricted put and call operators sheds some new light on the RND recovery
problem. The SRM improves on other RND recovery methods in the sense that:
  - it is fast and simple to implement since it requires solution of a single
quadratic program, while being fully nonparametric; - it takes the bid ask
quotes as sole input and does not require any sort of calibration, smoothing or
preprocessing of the data; - it is robust to the paucity of price quotes; - it
returns the smoothest density giving rise to prices that lie inside the bid ask
quotes. The estimated RND is therefore as well-behaved as can be; - it returns
a closed form estimate of the RND on the interval [0,B] of the positive real
line, where B is a positive constant that can be chosen arbitrarily. We thus
obtain both the middle part of the RND together with its full left tail and
part of its right tail.
  We confront this method to both real and simulated data and observe that it
fares well in practice. The SRM is thus found to be a promising alternative to
other RND recovery methods.


title: Neutron-rich Helium isotopes based on hyperspherical harmonics

abstract:
  We present recent results for neutron-rich Helium isotopes obtained from the
hyperspherical harmonics method. Ground-state properties, like the binding
energy and the point-proton radius are shown for the two-neutron halo nucleus
6He using two-body low-momentum interactions derived from chiral forces. The
applicability of the method to the four-neutron halo nucleus 8He is discussed.
As an excited-state observable we present a recent calculation of the nuclear
electric polarizability of $^6$He from a semi-realistic potential. A comparison
of the calculated quantities to experimental data is performed.


title: Toric grammars: a new statistical approach to natural language modeling

abstract:
  We propose a new statistical model for computational linguistics. Rather than
trying to estimate directly the probability distribution of a random sentence
of the language, we define a Markov chain on finite sets of sentences with many
finite recurrent communicating classes and define our language model as the
invariant probability measures of the chain on each recurrent communicating
class. This Markov chain, that we call a communication model, recombines at
each step randomly the set of sentences forming its current state, using some
grammar rules. When the grammar rules are fixed and known in advance instead of
being estimated on the fly, we can prove supplementary mathematical properties.
In particular, we can prove in this case that all states are recurrent states,
so that the chain defines a partition of its state space into finite recurrent
communicating classes. We show that our approach is a decisive departure from
Markov models at the sentence level and discuss its relationships with Context
Free Grammars. Although the toric grammars we use are closely related to
Context Free Grammars, the way we generate the language from the grammar is
qualitatively different. Our communication model has two purposes. On the one
hand, it is used to define indirectly the probability distribution of a random
sentence of the language. On the other hand it can serve as a (crude) model of
language transmission from one speaker to another speaker through the
communication of a (large) set of sentences.


title: What can be decided locally without identifiers?

abstract:
  Do unique node identifiers help in deciding whether a network $G$ has a
prescribed property $P$? We study this question in the context of distributed
local decision, where the objective is to decide whether $G \in P$ by having
each node run a constant-time distributed decision algorithm. If $G \in P$, all
the nodes should output yes; if $G \notin P$, at least one node should output
no.
  A recent work (Fraigniaud et al., OPODIS 2012) studied the role of
identifiers in local decision and gave several conditions under which
identifiers are not needed. In this article, we answer their original question.
More than that, we do so under all combinations of the following two critical
variations on the underlying model of distributed computing:
  ($B$): the size of the identifiers is bounded by a function of the size of
the input network; as opposed to ($\neg B$): the identifiers are unbounded.
  ($C$): the nodes run a computable algorithm; as opposed to ($\neg C$): the
nodes can compute any, possibly uncomputable function.
  While it is easy to see that under ($\neg B, \neg C$) identifiers are not
needed, we show that under all other combinations there are properties that can
be decided locally if and only if identifiers are present. Our constructions
use ideas from classical computability theory.


title:
Electronic and optical properties of Cadmium fluoride: the role of
  many-body effects

abstract:
  Electronic excitations and optical spectra of $CdF_{2}$ are calculated up to
ultraviolet employing state-of-the-art techniques based on density functional
theory and many-body perturbation theory. The GW scheme proposed by Hedin has
been used for the electronic self-energy to calculate single-particle
excitation properties as energy bands and densities of states. For optical
properties many-body effects, treated within the Bethe-Salpeter equation
framework, turn out to be crucial. A bound exciton located about 1 eV below the
quasiparticle gap is predicted. Within the present scheme the optical
absorption spectra and other optical functions show an excellent agreement with
experimental data. Moreover, we tested different schemes to obtain the best
agreement with experimental data. Among the several schemes, we suggest a
self-consistent quasiparticle energy scheme.


title:
Inference of the Universal Constancy of Planck Constant based on First
  Principles

abstract:
  Since its discovery by Max Planck in 1900, the Planck constant $h$ has been
demonstrated to be an universal constant, and its numerical value has been
accurately determined based on experiments. Up to the present however the
physical origin of this fundamental constant has not been well understood, and
the numerical value of it has not been {\it ab initio} predicted. $h$ is
characteristic in two respects: 1) it is a universal constant with respect to
all (quasi-) stationary dynamical processes of all matter particles and
radiation fields, and 2) it has a specific numerical value. A theoretical
inference of $h$, and a corresponding accounting for the physical origin of
$h$, therefore needs be achieved in both respects. This paper presents a
theoretical exploration in the first respect, a mathematical inference of the
universal constancy of $h$, based on the second law of thermodynamics, the
principle of least action and the probability theory.


title: A note on Gibbs paradox

abstract:
  We show in this note that Gibbs paradox arises not due to application of
thermodynamic principles, whether classical or statistical or even quantum
mechanical, but due to incorrect application of mathematics to the process of
mixing of ideal gases.


title:
Proton decay and $\mu\to e+\gamma$ Connection in a Renormalizable SO(10)
  GUT for Neutrinos

abstract:
  Supersymmetric SO(10) grand unified models with renormalizable Yukawa
couplings involving {\bf 10}, {\bf 126} and {\bf 120} Higgs fields have been
shown to give a very economical theory for understanding quark-lepton flavor in
a unified framework. In previous papers, we showed how nucleon decay can be
suppressed in these models without invoking cancellation, by choice of Yukawa
flavor texture within a type II seesaw framework for neutrinos that explains
all mixings and masses including the recently observed "large" $\theta_{13}$.
In this follow-up paper, we extend our earlier work to the case of type I
seesaw and show that the recently measured "large" $\theta_{13}$ can be
accommodated in this case while suppressing proton decay. We then point out
that the two cases (type I and II) lead to different testable predictions for
$B(\mu\to e+\gamma)$ and $B(\tau\to \mu (e) +\gamma)$ as well as different
flavor final states in nucleon decay. In particular, we find that for the type
I seesaw case, $B(\tau\to \mu +\gamma)$ can be observable while at the same
time suppressing $B(\mu\to e+\gamma)$, whereas in the type II seesaw case,
$B(\tau\to \mu +\gamma)$ is always suppressed whereas $B(\mu\to e+\gamma)$ is
observable.


title: Coded aperture compressive temporal imaging

abstract:
  We use mechanical translation of a coded aperture for code division multiple
access compression of video. We present experimental results for reconstruction
at 148 frames per coded snapshot.


title:
The trace norm constrained matrix-variate Gaussian process for multitask
  bipartite ranking

abstract:
  We propose a novel hierarchical model for multitask bipartite ranking. The
proposed approach combines a matrix-variate Gaussian process with a generative
model for task-wise bipartite ranking. In addition, we employ a novel trace
constrained variational inference approach to impose low rank structure on the
posterior matrix-variate Gaussian process. The resulting posterior covariance
function is derived in closed form, and the posterior mean function is the
solution to a matrix-variate regression with a novel spectral elastic net
regularizer. Further, we show that variational inference for the trace
constrained matrix-variate Gaussian process combined with maximum likelihood
parameter estimation for the bipartite ranking model is jointly convex. Our
motivating application is the prioritization of candidate disease genes. The
goal of this task is to aid the identification of unobserved associations
between human genes and diseases using a small set of observed associations as
well as kernels induced by gene-gene interaction networks and disease
ontologies. Our experimental results illustrate the performance of the proposed
model on real world datasets. Moreover, we find that the resulting low rank
solution improves the computational scalability of training and testing as
compared to baseline models.


title: A Study on Spectral Efficiency of Physical Layer over Cognitive Radio

abstract:
  Despite the conclusive potential of cognitive radio for provisioning the
dynamic and flexible spectrum/channel allocation, the research community should
study the performance gain of physical layer over such a radio with cognition
capabilities. To this end, several mechanisms of physical layers such as
adaptive modulation, multiple-input multiple output antennas; channel coding
and/or combination of them should be studied. These studies should be
accomplished in terms of spectral efficiency. Therefore, the gain of cognitive
radio in wireless networks available into the market will be identified
practically. Another issue under consideration should be the performance
evaluation of cognitive radio assuming a cross-layer combination between the
cognitive physical and the upper layers. To this direction, this paper presents
a study on spectral efficiency at the physical layer with cognitive
capabilities. In sequel, we study a cross-layer combination of physical layer
with upper layers in the same cognitive context. The performance gain of
cognitive radio in such a physical layer is realized practically as well as a
few cross-layer design issues have been raised.


title:
On some physical aspects of isotropic cosmology in Riemann-Cartan
  spacetime

abstract:
  Isotropic cosmology built in the framework of the Poincar\'e gauge theory of
gravity based on sufficiently general expression of gravitational Lagrangian is
considered. The derivation of cosmological equations and equations for torsion
functions in the case of the most general homogeneous isotropic models is
given. Physical aspects of isotropic cosmology connected with possible solution
of dark energy problem and problem of cosmological singularity are discussed.


title: Jet physics in heavy-ion collisions

abstract:
  Jets are expected to play a prominent role in the ongoing efforts to
characterize the hot and dense QCD medium created in ultrarelativistic heavy
ion collisions. The success of this program depends crucially on the existence
of a full theoretical account of the dynamical effects of the medium on the
jets that develop within it. By focussing on the discussion of the essential
ingredients underlying such a theoretical formulation, we aim to set the
appropriate context in which current and future developments can be understood.


title: Quiver polynomials in iterated residue form

abstract:
  Degeneracy loci polynomials for quiver representations generalize several
important polynomials in algebraic combinatorics. In this paper we give a
nonconventional generating sequence description of these polynomials, when the
quiver is of Dynkin type.


title:
Spinning particle in a varying magnetic field: how work is done by
  changing external parameter

abstract:
  The work done by a spinning particle, or on it, when put into a varying
magnetic field is discussed.


title: Rapid Depresurizations: Can they lead to irreversible damage?

abstract:
  Rapid gas depressurization leads to gas cooling that is followed by slow gas
warming when the cavern is kept idle. The decrease in the temperature of gas
depends upon the relative withdrawal rate (in %/day), and cavern size and
shape. Gas cooling may result in the onset of tensile stresses at cavern walls
and roofs that may generate fractures or cracks. However, in most cases, the
depth of penetration of these fractures is small, and they are perpendicular to
the cavern wall. The distance between two parallel fractures becomes larger
when fractures penetrate deeper into the rock mass, as some fractures stop
growing. Fractures form a polygonal pattern. Salt slabs are created, with
boundaries formed by the opened fractures. As long as the depth of penetration
of the fracture remains small, these slabs remain strongly bonded to the rock
mass, and it is believed that, in many cases, their weights are not large
enough to allow them to break off the cavern wall.