title: Linear-Quadratic $N$-person and Mean-Field Games with Ergodic Cost

abstract:
  We consider stochastic differential games with $N$ players, linear-Gaussian
dynamics in arbitrary state-space dimension, and long-time-average cost with
quadratic running cost. Admissible controls are feedbacks for which the system
is ergodic. We first study the existence of affine Nash equilibria by means of
an associated system of $N$ Hamilton-Jacobi-Bellman and $N$
Kolmogorov-Fokker-Planck partial differential equations. We give necessary and
sufficient conditions for the existence and uniqueness of quadratic-Gaussian
solutions in terms of the solvability of suitable algebraic Riccati and
Sylvester equations. Under a symmetry condition on the running costs and for
nearly identical players we study the large population limit, $N$ tending to
infinity, and find a unique quadratic-Gaussian solution of the pair of Mean
Field Game HJB-KFP equations. Examples of explicit solutions are given, in
particular for consensus problems.


title:
Statistical Mechanics Model for the Dynamics of Collective Epigenetic
  Histone Modification

abstract:
  Epigenetic histone modifications play an important role in the maintenance of
different cell phenotypes. The exact molecular mechanism for inheritance of the
modification patterns over cell generations remains elusive. We construct a
Potts-type model based on experimentally observed nearest-neighbor enzyme
lateral interactions and nucleosome covalent modification state biased enzyme
recruitment. The model can lead to effective nonlocal interactions among
nucleosomes suggested in previous theoretical studies, and epigenetic memory is
robustly inheritable against stochastic cellular processes.


title: Universality of free homogeneous sums in every dimension

abstract:
  We prove a general multidimensional invariance principle for a family of
U-statistics based on freely independent non-commutative random variables of
the type $U_n(S)$, where $U_n(x)$ is the $n$-th Chebyshev polynomial and $S$ is
a standard semicircular element on a fixed $W^{\ast}$-probability space. As a
consequence, we deduce that homogeneous sums based on random variables of this
type are universal with respect to both semicircular and free Poisson
approximations.
  Our results are stated in a general multidimensional setting and can be seen
as a genuine extension of some recent findings by Deya and Nourdin; our
techniques are based on the combination of the free Lindeberg method and the
Fourth moment Theorem.


title: Mobile Offloading in Wireless Ad Hoc Networks

abstract:
  This paper describes a strategy that was designed, implemented, and presented
at the {\it Mobile Ad Hoc Networking Interoperability and Cooperation (MANIAC)
Challenge 2013}. The theme of the MANIAC Challenge 2013 was ``Mobile Data
Offloading,'' and consisted on developing and comparatively evaluating
strategies to offload infrastructure access points via customer ad hoc
forwarding using handheld devices (e.g., tablets and smartphones). According to
the challenge rules, a hop-by-hop bidding contest (or ``auction'') should
decide the path of each data packet towards its destination. Consequently, each
team should rely on other teams' willingness to forward packets for them in
order to get their traffic across the network. In this application scenario,
the incentive for customers to join the ad hoc network is discounted monthly
fees, while operators should benefit from decreased infrastructure costs.
Following the rules of MANIAC Challenge 2013, this paper proposes a strategy
that is based on the concept of how ``tight'' a node is to successfully deliver
a packet to its destination within a given deadline. This ``tightness'' idea
relies on a shortest-path analysis of the underlying network graph, and it is
used to define three sub-strategies that specify a) how to participate in an
auction; b) how to announce an auction; and c) how to decide who wins the
announced auction. The proposed strategy seeks to minimize network resource
utilization and to promote cooperative behavior among participant nodes.


title: Fractional Entropy Decaying and the Third Law of Thermodynamics

abstract:
  The quantum thermodynamic property of the fractional damping system is
investigated extensively. A fractional power-law decaying entropy function is
revealed which presents another evidence for the validity of the third law of
thermodynamics in the quantum dissipative region. Several non-trivial
characters are excavated such as that the entropy varies from a non-linear
diverging function to a semi-linear decaying function of the fractional
exponent as the temperature tends to absolute zero.


title:
Conformal Invariance and the Four Point Scalar Correlator in Slow-Roll
  Inflation

abstract:
  We calculate the four point correlation function for scalar perturbations in
the canonical model of slow-roll inflation. We work in the leading slow-roll
approximation where the calculation can be done in de Sitter space. Our
calculation uses techniques drawn from the AdS/CFT correspondence to find the
wave function at late times and then calculate the four point function from it.
The answer we get agrees with an earlier result in the literature, obtained
using different methods. Our analysis reveals a subtlety with regard to the
Ward identities for conformal invariance, which arises in de Sitter space and
has no analogue in AdS space. This subtlety arises because in de Sitter space
the metric at late times is a genuine degree of freedom, and hence to calculate
correlation functions from the wave function of the Universe at late times, one
must fix gauge completely. The resulting correlators are then invariant under a
conformal transformation accompanied by a compensating coordinate
transformation which restores the gauge.


title:
Local inhomogeneity and filamentary superconductivity in Pr-doped
  CaFe$_{2}$As$_{2}$

abstract:
  We use multi-scale techniques to determine the extent of local inhomogeneity
and superconductivity in Ca$_{0.86}$Pr$_{0.14}$Fe$_{2}$As$_{2}$ single crystal.
The inhomogeneity is manifested as a spatial variation of praseodymium
concentration, local density of states, and superconducting order parameter. We
show that the high-$T_{c}$ superconductivity emerges from clover-like defects
associated with Pr dopants. The highest $T_{c}$ is observed in both the
tetragonal and collapsed tetragonal phases, and its filamentary nature is a
consequence of non-uniform Pr distribution that develops localized, isolated
superconducting regions within the crystals.


title: B-Maniac

abstract:
  Mobile Data Offloading permits users to use cheap communication media,
whenever feasible, for delivering their personal data instead of using the
infrastructure which is more expensive. Having good procedures to assess and
compare the different possibilities a device has to send his data is crucial.
In the following paper, we propose an evaluating approach that takes into
consideration the topology changes history in order to provide an efficient way
to calculate the quality of a specific medium.
  In particular \textit{Bayesian Networks} are used as basis to provide our
solution to the Maniac Challenge 2013. Bayesian Networks is a statistical model
for the generation of inferences starting with very little information. In the
next sections we will give a definition of the Bayesian Networks focusing on
the simplest and computationally efficient of the Bayesian Networks versions,
named \textit{\naive Bayes}. Finally, we will show our method for the challenge
to evaluate the medium and the bid strategy.


title: On the interchange of alternating-amplitude pulsation cycles

abstract:
  We characterized the time intervals between the interchanges of the
alternating high- and low-amplitude extrema of three RV Tauri and three RR
Lyrae stars.


abstract:
  Some Tur\'an type inequalities for Struve functions of the first kind are
deduced by using various methods developed in the case of Bessel functions of
the first and second kind. New formulas, like Mittag-Leffler expansion,
infinite product representation for Struve functions of the first kind, are
obtained, which may be of independent interest. Moreover, some complete
monotonicity results and functional inequalities are deduced for Struve
functions of the second kind. These results complement naturally the known
results for a particular case of Lommel functions of the first kind, and for
modified Struve functions of the first and second kind.


title: Derivative of symmetric square p-adic L-functions via pull-back formula

abstract:
  In this paper we recall the method of Greenberg and Stevens to calculate
derivatives of p-adic L-functions using deformations of Galois representation
and we apply it to the symmetric square of a modular form Steinberg at p. Under
certain hypotheses on the conductor and the Nebentypus, this prove a conjecture
of Greenberg and Benois on trivial zeros.


title:
On the radiative and thermodynamic properties of the Cosmic Microwave
  Background radiation using COBE FIRAS instrument data

abstract:
  Use formulas to describe the monopole and dipole spectra of the Cosmic
Microwave Background (CMB) radiation, the exact expressions for the temperature
dependences of the radiative and thermodynamic functions, such as the total
radiation power per unit area, total energy density, number density of photons,
Helmholtz free energy density, entropy density, heat capacity at constant
volume, pressure, enthalpy density, and internal energy density in the finite
range of frequencies are obtained. Since the dependence of temperature upon the
redshift z is known, the obtained expressions can be simply presented in z
representation. Utilizing experimental data for the monopole and dipole spectra
measured by the COBE FIRAS instrument in the 60 - 600 GHz frequency interval at
the temperature T = 2.728 K, the values of the radiative and thermodynamic
functions, as well as the radiation density constant a and the Stefan-Boltzmann
constant are calculated. In the case of the dipole spectrum, the constants a
and the Stefan-Boltzmann constant, and the radiative and thermodynamic
properties of the CMB radiation are obtained using the mean amplitude Tamp =
3.369 m K. It is shown that the Doppler shift leads to a renormalization of the
radiation density constant a, the Stefan-Boltzmann constant, and the
corresponding constants for the thermodynamic functions. The radiative and
thermodynamic properties of the Cosmic Microwave Background radiation for the
monopole and dipole spectra at the redshift z = 1089 are calculated.


title: The Maximal Two-Sided Ideals of Nest Algebras

abstract:
  We give a necessary and sufficient criterion for an operator in a nest
algebra to belong to a proper two-sided ideal of that algebra. Using this
result, we describe the strong radical of a nest algebra, and give a general
description of the maximal two-sided ideals.


title: Computational Aspects of the Hausdorff Distance in Unbounded Dimension

abstract:
  We study the computational complexity of determining the Hausdorff distance
of two polytopes given in halfspace- or vertex-presentation in arbitrary
dimension. Subsequently, a matching problem is investigated where a convex body
is allowed to be homothetically transformed in order to minimize its Hausdorff
distance to another one. For this problem, we characterize optimal solutions,
deduce a Helly-type theorem and give polynomial time (approximation) algorithms
for polytopes.


title:
The large-g observability of the low-lying energies in the strongly
  singular potentials $V(x)=x^2+g^2/x^6$ after their PT-symmetric
  regularization

abstract:
  The elementary quadratic plus inverse sextic interaction containing a
strongly singular repulsive core in the origin is made regular by a complex
shift of coordinate $x = s-{\rm i}\varepsilon$. The shift $\varepsilon>0$ is
fixed while the value of $s$ is kept real and potentially observable, $s \in
(-\infty,\infty)$. The low-lying energies of bound states are found in closed
form for the large couplings $g$. Within the asymptotically vanishing ${\cal
O}(g^{-1/4})$ error bars these energies are real so that the time-evolution of
the system may be expected unitary in an {\em ad hoc} physical Hilbert space.


title: Accelerating ABC methods using Gaussian processes

abstract:
  Approximate Bayesian computation (ABC) methods are used to approximate
posterior distributions using simulation rather than likelihood calculations.
We introduce Gaussian process (GP) accelerated ABC, which we show can
significantly reduce the number of simulations required. As computational
resource is usually the main determinant of accuracy in ABC, GP-accelerated
methods can thus enable more accurate inference in some models. GP models of
the unknown log-likelihood function are used to exploit continuity and
smoothness, reducing the required computation. We use a sequence of models that
increase in accuracy, using intermediate models to rule out regions of the
parameter space as implausible. The methods will not be suitable for all
problems, but when they can be used, can result in significant computational
savings. For the Ricker model, we are able to achieve accurate approximations
to the posterior distribution using a factor of 100 fewer simulator evaluations
than comparable Monte Carlo approaches, and for a population genetics model we
are able to approximate the exact posterior for the first time.


title:
DART-Ray: a 3D ray-tracing radiative transfer code for calculating the
  propagation of light in dusty galaxies

abstract:
  We present DART-Ray, a new ray-tracing 3D dust radiative transfer (RT) code
designed specifically to calculate radiation field energy density (RFED)
distributions within dusty galaxy models with arbitrary geometries. In this
paper we introduce the basic algorithm implemented in DART-Ray which is based
on a pre-calculation of a lower limit for the RFED distribution. This
pre-calculation allows us to estimate the extent of regions around the
radiation sources within which these sources contribute significantly to the
RFED. In this way, ray-tracing calculations can be restricted to take place
only within these regions, thus substantially reducing the computational time
compared to a complete ray-tracing RT calculation. Anisotropic scattering is
included in the code and handled in a similar fashion. Furthermore, the code
utilizes a Cartesian adaptive spatial grid and an iterative method has been
implemented to optimize the angular densities of the rays originated from each
emitting cell. In order to verify the accuracy of the RT calculations performed
by DART-Ray, we present results of comparisons with solutions obtained using
the DUSTY 1D RT code for a dust shell illuminated by a central point source and
existing 2D RT calculations of disc galaxies with diffusely distributed stellar
emission and dust opacity. Finally, we show the application of the code on a
spiral galaxy model with logarithmic spiral arms in order to measure the effect
of the spiral pattern on the attenuation and RFED.


title: Characterizing \tau-rigid-finite algebras with radical square zero

abstract:
  In this paper, we give a characterization of tau-rigid-finite algebras with
radical square zero in terms of the separated quivers, which is an analog of a
famous characterization of representation-finite algebras with radical square
zero.


title:
Holder's inequalities involving the infinite product and their
  applications in martingale spaces

abstract:
  We give H\"older's inequalities for integral and conditional expectation
involving the infinite product. Moreover, a generalized Doob maximal operator
is introduced and weighted inequalities for the operator are established.


title: A Redshift Survey of the Strong Lensing Cluster Abell 383

abstract:
  Abell 383 is a famous rich cluster (z = 0.1887) imaged extensively as a basis
for intensive strong and weak lensing studies. Nonetheless there are few
spectroscopic observations. We enable dynamical analyses by measuring 2360 new
redshifts for galaxies with r$_{petro} \leq 20.5$ and within 50$^\prime$ of the
BCG (Brightest Cluster Galaxy: R.A.$_{2000} = 42.014125^\circ$, Decl$_{2000} =
-03.529228^\circ$). We apply the caustic technique to identify 275 cluster
members within 7$h^{-1}$ Mpc of the hierarchical cluster center. The BCG lies
within $-11 \pm 110$ km s$^{-1}$ and 21 $\pm 56 h^{-1}$ kpc of the hierarchical
cluster center; the velocity dispersion profile of the BCG appears to be an
extension of the velocity dispersion profile based on cluster members. The
distribution of cluster members on the sky corresponds impressively with the
weak lensing contours of Okabe et al. (2010) especially when the impact of
foreground and background structure is included. The values of R$_{200}$ =
$1.22\pm 0.01 h^{-1}$ Mpc and M$_{200}$ = $(5.07 \pm 0.09)\times 10^{14}
h^{-1}$ M$_\odot$ obtained by application of the caustic technique agree well
with recent completely independent lensing measures. The caustic estimate
extends direct measurement of the cluster mass profile to a radius of $\sim 5
h^{-1}$ Mpc.


title:
Baryon states with open beauty in the extended local hidden gauge
  approach

abstract:
  In this paper we examine the interaction of \bar B N, \bar B \Delta, \bar B^*
N and \bar B^* \Delta states, together with their coupled channels, using a
mapping from the light meson sector. The assumption that the heavy quarks act
as spectators at the quark level automatically leads us to the results of the
heavy quark spin symmetry for pion exchange and reproduces the results of the
Weinberg Tomozawa term, coming from light vector exchanges in the extended
local hidden gauge approach. With this dynamics we look for states dynamically
generated from the interaction and find two states with nearly zero width,
which we associate to the \Lambda_b(5912) and \Lambda_b(5920) states. The
states couple mostly to \bar B^* N, which are degenerate with the Weinberg
Tomozawa interaction. The difference of masses between these two states, with
J=1/2, 3/2 respectively, is due to pion exchange connecting these states to
intermediate \bar B N states. In addition to these two \Lambda_b states, we
find three more states with I=0, one of them nearly degenerate in two states of
J=1/2,3/2. Furthermore we also find eight more states in $I=1$, two of them
degenerate in J=1/2, 3/2, and other two degenerate in J=1/2, 3/2, 5/2.


title: Random partitions in statistical mechanics

abstract:
  We consider a family of distributions on spatial random partitions that
provide a coupling between different models of interest: the ideal Bose gas;
the zero-range process; particle clustering; and spatial permutations. These
distributions are invariant for a "chain of Chinese restaurants" stochastic
process. We obtain results for the distribution of the size of the largest
component.


title:
First and second moments for self-similar couplings and Wasserstein
  distances

abstract:
  We study aspects of the Wasserstein distance in the context of self-similar
measures. Computing this distance between two measures involves minimising
certain moment integrals over the space of \emph{couplings}, which are measures
on the product space with the original measures as prescribed marginals. We
focus our attention on self-similar measures associated to equicontractive
iterated function systems satisfying the open set condition and consisting of
two maps on the unit interval. We are particularly interested in understanding
the restricted family of \emph{self-similar} couplings and our main achievement
is the explicit computation of the 1st and 2nd moment integrals for such
couplings. We show that this family is enough to yield an explicit formula for
the 1st Wasserstein distance and provide non-trivial upper and lower bounds for
the 2nd Wasserstein distance.


title: Generalised Ap\'ery numbers modulo $9$

abstract:
  We characterise the modular behaviour of (generalised) Ap\'ery number modulo
$9$, thereby in particular establishing two conjectures in "A method for
determining the mod-$3^k$ behaviour of recursive sequences" [arXiv:1308.2856].


title:
Qualitative analysis of a Lotka-Volterra competition system with
  advection

abstract:
  We study a diffusive Lotka-Volterra competition system with advection under
Neumann boundary conditions. Our system models a competition relationship that
one species escape from the region of high population density of their
competitors in order to avoid competitions. We establish the global existence
of bounded classical solutions for the system in one-dimensional domain. For
multi-dimensional domains, globally bounded classical solutions are obtained
for a parabolic-elliptic system under proper assumptions on the system
parameters. These global existence results make it possible to study bounded
steady states in order to model species segregation phenomenon. We then
investigate the stationary problem in one-dimensional domains. Through
bifurcation theory, we obtain the existence of nonconstant positive steady
states, which are small perturbations from the positive equilibrium; we also
study the stability of these bifurcating solutions when the diffusion
coefficient of the escaper is large and the diffusion coefficient of its
competitor is small. In the limit of large advection rate, we show that the
reaction-advection-diffusion system converges to a shadow system involving the
competitor population density and an unknown positive constant. The existence
and stability of positive solutions to the shadow system have also been
obtained through bifurcation theories. Finally, we construct positive solutions
with an interior transition layer to the shadow system when the crowding rate
of the escaper and the diffusion rate of its interspecific competitors are
sufficiently small. The transition-layer solutions can be used to model the
species segregation phenomenon.


title:
Manifold approach for a many-body Wannier-Stark system: localization and
  chaos in energy space

abstract:
  We study the resonant tunneling effect in a many-body Wannier-Stark system,
realized by ultracold bosonic atoms in an optical lattice subjected to an
external Stark force. The properties of the many-body system are effectively
described in terms of upper-band excitation manifolds, which allow for the
study of the transition between regular and quantum chaotic spectral
statistics. We show that our system makes it possible to control the spectral
statistics locally in energy space by the competition of the force and the
interparticle interaction. By a time-dependent sweep of the Stark force the
dynamics is reduced to a Landau-Zener problem in the single-particle setting.


title:
Dynamical quarks effects on the gluon propagation and chiral symmetry
  restoration

abstract:
  We exploit the recent lattice results for the infrared gluon propagator with
light dynamical quarks and solve the gap equation for the quark propagator.
Chiral symmetry breaking and confinement (intimately tied with the analytic
properties of QCD Schwinger functions) order parameters are then studied.


title: Linear Temporal Logic for Regular Cost Functions

abstract:
  Regular cost functions have been introduced recently as an extension to the
notion of regular languages with counting capabilities, which retains strong
closure, equivalence, and decidability properties. The specificity of cost
functions is that exact values are not considered, but only estimated. In this
paper, we define an extension of Linear Temporal Logic (LTL) over finite words
to describe cost functions. We give an explicit translation from this new logic
to two dual form of cost automata, and we show that the natural decision
problems for this logic are PSPACE-complete, as it is the case in the classical
setting. We then algebraically characterize the expressive power of this logic,
using a new syntactic congruence for cost functions introduced in this paper.


title:
On-shell constrained $M_2$ variables with applications to mass
  measurements and topology disambiguation

abstract:
  We consider a class of on-shell constrained mass variables that are 3+1
dimensional generalizations of the Cambridge $M_{T2}$ variable and that
automatically incorporate various assumptions about the underlying event
topology. The presence of additional on-shell constraints causes their
kinematic distributions to exhibit sharper endpoints than the usual $M_{T2}$
distribution. We study the mathematical properties of these new variables,
e.g., the uniqueness of the solution selected by the minimization over the
invisible particle 4-momenta. We then use this solution to reconstruct the
masses of various particles along the decay chain. We propose several tests for
validating the assumed event topology in missing energy events from new
physics. The tests are able to determine: 1) whether the decays in the event
are two-body or three-body, 2) if the decay is two-body, whether the
intermediate resonances in the two decay chains are the same, and 3) the exact
sequence in which the visible particles are emitted from each decay chain.


title:
A Recursive Algorithmic Approach to the Finding of Permutations for the
  Combination of Any Two Sets

abstract:
  In this paper I present a conjecture for a recursive algorithm that finds
each permutation of combining two sets of objects (AKA the Shuffle Product).
This algorithm provides an efficient way to navigate this problem, as each
atomic operation yields a permutation of the union. The permutations of the
union of the two sets are represented as binary integers which are then
manipulated mathematically to find the next permutation. The routes taken to
find each of the permutations then form a series of associations or adjacencies
which can be represented in a tree graph which appears to possess some
properties of a fractal.
  This algorithm was discovered while attempting to identify every possible
end-state of a Tic-Tac-Toe (Naughts and Crosses) board. It was found to be a
viable and efficient solution to the problem, and now---in its more generalized
state---it is my belief that it may find applications among a wide range of
theoretical and applied sciences.
  I hypothesize that, due to the fractal-like nature of the tree it traverses,
this algorithm sheds light on a more generic principle of combinatorics and as
such could be further generalized to perhaps be applied to the union of any
number of sets.


title: Smart Grid Demand Monitoring Model

abstract:
  This paper is in related to the demand genrated by the consumer for a time
for the power which is being viewed by taking some measures to solve the demand
need.


title: Holographic Equipartition and Gravitational Collapse

abstract:
  It is argued in the literature that gravity is an emergent phenomenon and is
a statistical tendency for a gravitational system to attain the maximal entropy
state which maintains the holographic principle. In this paper, we show that
gravitational collapse is due to the same mechanism as the expansion of the
universe that the departure of the surface degrees of freedom and the bulk
degrees of freedom in a region of space drives the evolution of a gravitational
system. We also argue that the ordinary thermal radiation can be taken as a
signal for the existence of some kind of "confined" bulk degrees of freedom
which prevent a gravitational system from collapse. When the mount of
"confined" bulk degrees of freedom is not adequate, the collapse occurs untill
an new equilibrium is attained. Our rusults provide a new paradigm to
understand the gravitational collapse.


title:
Characterizing weak chaos in nonintegrable Hamiltonian systems: the
  fundamental role of stickiness and initial conditions

abstract:
  Weak chaos in high-dimensional conservative systems can be characterized
through sticky effect induced by invariant structures on chaotic trajectories.
Suitable quantities for this characterization are the higher cummulants of the
finite time Lyapunov exponents (FTLEs) distribution. They gather the {\it
whole} phase space relevant dynamics in {\it one} quantity and give
informations about ordered and random states. This is analyzed here for
discrete Hamiltonian systems with local and global couplings. It is also shown
that FTLEs plotted {\it versus} initial condition (IC) and the nonlinear
parameter is essential to understand the fundamental role of ICs in the
dynamics of weakly chaotic Hamiltonian systems.


title:
Short-time existence for the second order renormalization group flow in
  general dimensions

abstract:
  We prove local existence for the second order Renormalization Group flow
initial value problem on closed Riemannian manifolds $(M,g)$ in general
dimensions, for initial metrics whose sectional curvatures $K_P$ satisfy the
condition $1+\alpha K_P > 0$, at all points $p \in M$ and planes $P \subset T_p
M$. This extends results previously proven for two and three dimensions.


title:
Quantum Deformation of the Effective Theory on Non-Abelian string and
  2D-4D correspondence

abstract:
  We explore non-Abelian strings in the r=N-1 vacuum of N=2 supersymmetric QCD
with the gauge group U(N) and N_f flavors of quarks (N_f\geq N), where r is the
number of condensed quarks. N=2 supersymmetry is broken down to N=1 by a small
mass term for the adjoint matter. We discover that the low-energy
two-dimensional theory on the string world-sheet receives nonperturbative
corrections from the bulk, through the bulk gaugino condensate. This is in
contradistinction with the r=N vacuum situation, in which nonperturbative
effects on the world sheet are determined by internal dynamics of the
world-sheet theory. The 2D-4D correspondence (the coincidence of spectra of
two-dimensional kinks and four-dimensional monopoles) remains valid in the BPS
sector. Nonperturbative bulk effects deforming the weighted CP model on the
world sheet are found by virtue of the method of resolvents suggested by
Gaiotto, Gukov and Seiberg for surface defects. In the r=N vacuum the gaugino
condensate in the bulk vanishes, and there are no "outside" nonperturbative
corrections on the world sheet.


title: Using temporal IDF for efficient novelty detection in text streams

abstract:
  Novelty detection in text streams is a challenging task that emerges in quite
a few different scenarios, ranging from email thread filtering to RSS news feed
recommendation on a smartphone. An efficient novelty detection algorithm can
save the user a great deal of time and resources when browsing through relevant
yet usually previously-seen content. Most of the recent research on detection
of novel documents in text streams has been building upon either geometric
distances or distributional similarities, with the former typically performing
better but being much slower due to the need of comparing an incoming document
with all the previously-seen ones. In this paper, we propose a new approach to
novelty detection in text streams. We describe a resource-aware mechanism that
is able to handle massive text streams such as the ones present today thanks to
the burst of social media and the emergence of the Web as the main source of
information. We capitalize on the historical Inverse Document Frequency (IDF)
that was known for capturing well term specificity and we show that it can be
used successfully at the document level as a measure of document novelty. This
enables us to avoid similarity comparisons with previous documents in the text
stream, thus scaling better and leading to faster execution times. Moreover, as
the collection of documents evolves over time, we use a temporal variant of IDF
not only to maintain an efficient representation of what has already been seen
but also to decay the document frequencies as the time goes by. We evaluate the
performance of the proposed approach on a real-world news articles dataset
created for this task. The results show that the proposed method outperforms
all of the baselines while managing to operate efficiently in terms of time
complexity and memory usage, which are of great importance in a mobile setting
scenario.


title:
Measures of Causality in Complex Datasets with application to financial
  data

abstract:
  This article investigates the causality structure of financial time series.
We concentrate on three main approaches to measuring causality: linear Granger
causality, kernel generalisations of Granger causality (based on ridge
regression and the Hilbert--Schmidt norm of the cross-covariance operator) and
transfer entropy, examining each method and comparing their theoretical
properties, with special attention given to the ability to capture nonlinear
causality. We also present the theoretical benefits of applying non-symmetrical
measures rather than symmetrical measures of dependence. We apply the measures
to a range of simulated and real data. The simulated data sets were generated
with linear and several types of nonlinear dependence, using bivariate, as well
as multivariate settings. An application to real-world financial data
highlights the practical difficulties, as well as the potential of the methods.
We use two real data sets: (1) U.S. inflation and one-month Libor; (2) S$\&$P
data and exchange rates for the following currencies: AUDJPY, CADJPY, NZDJPY,
AUDCHF, CADCHF, NZDCHF. Overall, we reach the conclusion that no single method
can be recognised as the best in all circumstances, and each of the methods has
its domain of best applicability. We also highlight areas for improvement and
future research.


title:
Generalized friendship paradox in complex networks: The case of
  scientific collaboration

abstract:
  The friendship paradox states that your friends have on average more friends
than you have. Does the paradox "hold" for other individual characteristics
like income or happiness? To address this question, we generalize the
friendship paradox for arbitrary node characteristics in complex networks. By
analyzing two coauthorship networks of Physical Review journals and Google
Scholar profiles, we find that the generalized friendship paradox (GFP) holds
at the individual and network levels for various characteristics, including the
number of coauthors, the number of citations, and the number of publications.
The origin of the GFP is shown to be rooted in positive correlations between
degree and characteristics. As a fruitful application of the GFP, we suggest
effective and efficient sampling methods for identifying high characteristic
nodes in large-scale networks. Our study on the GFP can shed lights on
understanding the interplay between network structure and node characteristics
in complex networks.


title: Noncommutative Kahler Geometry of the Standard Podles Sphere

abstract:
  Building on the now established presentation of the standard Podles sphere as
an example of a noncommutative complex structure, we investigate how its
classical Kahler geometry behaves under $q$-deformation. Discussed are
noncommutative versions of Hodge decomposition, Lefschetz decomposition, the
Kahler identities, and the refinement of de Rham cohomology by Dolbeault
cohomology


title: Maximal Sharing in the Lambda Calculus with letrec

abstract:
  Increasing sharing in programs is desirable to compactify the code, and to
avoid duplication of reduction work at run-time, thereby speeding up execution.
We show how a maximal degree of sharing can be obtained for programs expressed
as terms in the lambda calculus with letrec. We introduce a notion of `maximal
compactness' for lambda-letrec-terms among all terms with the same infinite
unfolding. Instead of defined purely syntactically, this notion is based on a
graph semantics. lambda-letrec-terms are interpreted as first-order term graphs
so that unfolding equivalence between terms is preserved and reflected through
bisimilarity of the term graph interpretations. Compactness of the term graphs
can then be compared via functional bisimulation.
  We describe practical and efficient methods for the following two problems:
transforming a lambda-letrec-term into a maximally compact form; and deciding
whether two lambda-letrec-terms are unfolding-equivalent. The transformation of
a lambda-letrec-term $L$ into maximally compact form $L_0$ proceeds in three
steps:
  (i) translate L into its term graph $G = [[ L ]]$; (ii) compute the maximally
shared form of $G$ as its bisimulation collapse $G_0$; (iii) read back a
lambda-letrec-term $L_0$ from the term graph $G_0$ with the property $[[ L_0 ]]
= G_0$. This guarantees that $L_0$ and $L$ have the same unfolding, and that
$L_0$ exhibits maximal sharing.
  The procedure for deciding whether two given lambda-letrec-terms $L_1$ and
$L_2$ are unfolding-equivalent computes their term graph interpretations $[[
L_1 ]]$ and $[[ L_2 ]]$, and checks whether these term graphs are bisimilar.
  For illustration, we also provide a readily usable implementation.


title:
Optical conductivity of a two-dimensional metal at the onset of
  spin-density-wave order

abstract:
  We consider the optical conductivity of a clean two-dimensional metal near a
quantum spin-density-wave transition. Critical magnetic fluctuations are known
to destroy fermionic coherence at "hot spots" of the Fermi surface but coherent
quasiparticles survive in the rest of the Fermi surface. A large part of the
Fermi surface is not really "cold" but rather "lukewarm" in a sense that
coherent quasiparticles in that part survive but are strongly renormalized
compared to the non-interacting case. We discuss the self-energy of lukewarm
fermions and their contribution to the optical conductivity, $\sigma(\Omega)$,
focusing specifically on scattering off composite bosons made of two critical
magnetic fluctuations. Recent study [S.A. Hartnoll et al., Phys. Rev. B {\bf
84}, 125115 (2011)] found that composite scattering gives the strongest
contribution to the self-energy of lukewarm fermions and suggested that this
may give rise to non-Fermi liquid behavior of the optical conductivity at the
lowest frequencies. We show that the most singular term in the conductivity
coming from self-energy insertions into the conductivity bubble,
$\sigma'(\Omega)\propto \ln^3\Omega/\Omega^{1/3}$, is canceled out by the
vertex-correction and Aslamazov-Larkin diagrams. However, the cancelation does
not hold beyond logarithmic accuracy, and the remaining conductivity still
diverges as $1/\Omega^{1/3}$. We further argue that the $1/\Omega^{1/3}$
behavior holds only at asymptotically low frequencies, well inside the
frequency range affected by superconductivity. At larger $\Omega$, up to
frequencies above the Fermi energy, $\sigma'(\Omega)$ scales as $1/\Omega$,
which is reminiscent of the behavior observed in the superconducting cuprates.


title:
Systematically Searching for New Resonances at the Energy Frontier using
  Topological Models

abstract:
  We propose a new strategy to systematically search for new physics processes
in particle collisions at the energy frontier. An examination of all possible
topologies which give identifiable resonant features in a specific final state
leads to a tractable number of `topological models' per final state and gives
specific guidance for their discovery. Using one specific final state,
$\ell\ell jj$, as an example, we find that the number of possibilities is
reasonable and reveals simple, but as-yet-unexplored, topologies which contain
significant discovery potential. We propose analysis techniques and estimate
the sensitivity for $pp$ collisions with $\sqrt{s}=14$ TeV and
$\mathcal{L}=300$ fb$^{-1}$.


title: Asymptotically hyperbolic black holes in Horava gravity

abstract:
  Solutions of Horava gravity that are asymptotically Lifshitz are explored.
General near boundary expansions allow the calculation of the mass of these
spacetimes via a Hamiltonian method. Both analytic and numeric solutions are
studied which exhibit a causal boundary called the universal horizon, and are
therefore black holes of the theory. The thermodynamics of an asymptotically
Anti-de Sitter Horava black hole are verified.


title: Unbound Star-forming Molecular Clouds

abstract:
  We explore whether observed molecular clouds could include a substantial
population of unbound clouds. Using simulations which include only turbulence
and gravity, we are able to match observed relations and naturally reproduce
the observed scatter in the cloud size-linewidth coefficient, at fixed surface
density. We identify the source of this scatter as a spread in the intrinsic
virial parameter. Thus these observational trends do not require that clouds
exist in a state of dynamical equilibrium. We demonstrate that cloud virial
parameters can be accurately determined observationally with an appropriate
size estimator. All our simulated clouds eventually form collapsing cores,
regardless of whether the cloud is bound overall. This supports the idea that
molecular clouds do not have to be bound to form stars or to have observed
properties like those of nearby low-mass clouds.


title: Cortical prediction markets

abstract:
  We investigate cortical learning from the perspective of mechanism design.
First, we show that discretizing standard models of neurons and synaptic
plasticity leads to rational agents maximizing simple scoring rules. Second,
our main result is that the scoring rules are proper, implying that neurons
faithfully encode expected utilities in their synaptic weights and encode
high-scoring outcomes in their spikes. Third, with this foundation in hand, we
propose a biologically plausible mechanism whereby neurons backpropagate
incentives which allows them to optimize their usefulness to the rest of
cortex. Finally, experiments show that networks that backpropagate incentives
can learn simple tasks.


title:
A three-factor product construction for mutually orthogonal latin
  squares

abstract:
  It is well known that mutually orthogonal latin squares, or MOLS, admit a
(Kronecker) product construction. We show that, under mild conditions, `triple
products' of MOLS can result in a gain of one square. In terms of transversal
designs, the technique is to use a construction of Rolf Rees twice: once to
obtain a coarse resolution of the blocks after one product, and next to
reorganize classes and resolve the blocks of the second product. As
consequences, we report a few improvements to the MOLS table and obtain a
slight strengthening of the famous theorem of MacNeish.


title:
The sum $2^{\mathit{KA}(x)-\mathit{KP}(x)}$ over all prefixes $x$ of
  some binary sequence can be infinite

abstract:
  We consider two quantities that measure complexity of binary strings:
$\mathit{KA}(x)$ is defined as the minus logarithm of continuous a priori
probability on the binary tree, and $\mathit{KP}(x)$ denotes prefix complexity
of a binary string $x$. In this paper we answer a question posed by Joseph
Miller and prove that there exists an infinite binary sequence $\omega$ such
that the sum of $2^{\mathit{KA}(x)-\mathit{KP}(x)}$ over all prefixes $x$ of
$\omega$ is infinite. Such a sequence can be chosen among characteristic
sequences of computably enumerable sets.


title:
A cognitive analysis of Cauchy's conceptions of function, continuity,
  limit, and infinitesimal, with implications for teaching the calculus

abstract:
  In this paper we use theoretical frameworks from mathematics education and
cognitive psychology to analyse Cauchy's ideas of function, continuity, limit
and infinitesimal expressed in his Cours D'Analyse. Our analysis focuses on the
development of mathematical thinking from human perception and action into more
sophisticated forms of reasoning and proof, offering different insights from
those afforded by historical or mathematical analyses. It highlights the
conceptual power of Cauchy's vision and the fundamental change involved in
passing from the dynamic variability of the calculus to the modern
set-theoretic formulation of mathematical analysis. This offers a re-evaluation
of the relationship between the natural geometry and algebra of elementary
calculus that continues to be used in applied mathematics, and the formal set
theory of mathematical analysis that develops in pure mathematics and evolves
into the logical development of non-standard analysis using infinitesimal
concepts. It suggests that educational theories developed to evaluate student
learning are themselves based on the conceptions of the experts who formulate
them. It encourages us to reflect on the principles that we use to analyse the
developing mathematical thinking of students, and to make an effort to
understand the rationale of differing theoretical viewpoints.


title:
Cascading and Local-Field Effects in Non-Linear Optics Revisited; A
  Quantum-Field Picture Based on Exchange of Photons

abstract:
  The semi-classical theory of radiation-matter coupling misses local-field
effects that may alter the pulse time-ordering and cascading that leads to the
generation of new signals. These are then introduced macroscopically by solving
Maxwell's equations. This procedure is convenient and intuitive but ad hoc. We
show that both effects emerge naturally by including coupling to quantum modes
of the radiation field in the vacuum state to second order. This approach is
systematic and suggests a more general class of corrections that only arise in
a QED framework. In the semi-classical theory, which only includes classical
field modes, the susceptibility of a collection of $N$ non-interacting
molecules is additive and scales as $N$. Second-order coupling to a vacuum mode
generates an effective retarded interaction that leads to cascading and local
field effects both of which scale as $N^2$.


title:
Close-circuit domain quadruplets in BaTiO$_3$ nanorods embedded in
  SrTiO$_3$ film

abstract:
  Cylindrical BaTiO3 nanorods embedded in (100)-oriented SrTiO3 epitaxial film
in a brush-like configuration are investigated in the framework of the
Ginzburg-Landau-Devonshire model. It is shown that strain compatibility at
BaTiO3/SrTiO3 interfaces keeps BaTiO3 nanorods in the rhombohedral phase even
at room temperature. Depolarization field at the BaTiO3/SrTiO3 interfaces is
reduced by an emission of the 109-degree or 71-degree domain boundaries. In
case of nanorods of about 10-80 nm diameter, the ferroelectric domains are
found to form a quadruplet with a robust flux-closure arrangement of the
in-plane components of the spontaneous polarization. The out-of-plane
components of the polarization are either balanced or oriented up or down along
the nanorod axis. Switching of the out-of-plane polarization with coercive
field of about $5.10^6$ V/m occurs as a collapse of a 71-degree cylindrical
domain boundary formed at the curved circumference surface of the nanorod. The
remnant domain quadruplet configuration is chiral, with the $C_4$ macroscopic
symmetry. More complex stable domain configurations with coexisting clockwise
and anticlockwise quadruplets contain interesting arrangement of strongly
curved 71-degree boundaries.


title: Pairwise balanced designs with prescribed minimum dimension

abstract:
  The dimension of a linear space is the maximum positive integer $d$ such that
any $d$ of its points generate a proper subspace. For a set $K$ of integers at
least two, recall that a pairwise balanced design PBD$(v,K)$ is a linear space
on $v$ points whose lines (or blocks) have sizes belonging to $K$. We show
that, for any prescribed set of sizes $K$ and lower bound $d$ on the dimension,
there exists a PBD$(v,K)$ of dimension at least $d$ for all sufficiently large
and numerically admissible $v$.


title: Robust Proximity Search for Balls using Sublinear Space

abstract:
  Given a set of n disjoint balls b1, . . ., bn in IRd, we provide a data
structure, of near linear size, that can answer (1 \pm \epsilon)-approximate
kth-nearest neighbor queries in O(log n + 1/\epsilon^d) time, where k and
\epsilon are provided at query time. If k and \epsilon are provided in advance,
we provide a data structure to answer such queries, that requires (roughly)
O(n/k) space; that is, the data structure has sublinear space requirement if k
is sufficiently large.


title:
State-space model identification and feedback control of unsteady
  aerodynamic forces

abstract:
  Unsteady aerodynamic models are necessary to accurately simulate forces and
develop feedback controllers for wings in agile motion; however, these models
are often high dimensional or incompatible with modern control techniques.
Recently, reduced-order unsteady aerodynamic models have been developed for a
pitching and plunging airfoil by linearizing the discretized Navier-Stokes
equation with lift-force output. In this work, we extend these reduced-order
models to include multiple inputs (pitch, plunge, and surge) and explicit
parameterization by the pitch-axis location, inspired by Theodorsen's model.
Next, we investigate the na\"{\i}ve application of system identification
techniques to input--output data and the resulting pitfalls, such as unstable
or inaccurate models. Finally, robust feedback controllers are constructed
based on these low-dimensional state-space models for simulations of a rigid
flat plate at Reynolds number 100. Various controllers are implemented for
models linearized at base angles of attack $\alpha_0=0^\circ,
\alpha_0=10^\circ$, and $\alpha_0=20^\circ$. The resulting control laws are
able to track an aggressive reference lift trajectory while attenuating sensor
noise and compensating for strong nonlinearities.


title: Identities Involving Zeros of Ramanujan and Shanks Cubic Polynomials

abstract:
  In this paper we highlight the connection between Ramanujan cubic polynomials
(RCPs) and a class of polynomials, the Shanks cubic polynomials (SCPs), which
generate cyclic cubic fields. In this way we provide a new characterization for
RCPs and we express the zeros of any RCP in explicit form, using trigonometric
functions. Moreover, we observe that a cyclic transform of period three
permutes these zeros. As a consequence of these results we provide many new and
beautiful identities. Finally we connect RCPs to Gaussian periods, finding a
new identity, and we study some integer sequences related to SCPs .


title: Belief Revision in Structured Probabilistic Argumentation

abstract:
  In real-world applications, knowledge bases consisting of all the information
at hand for a specific domain, along with the current state of affairs, are
bound to contain contradictory data coming from different sources, as well as
data with varying degrees of uncertainty attached. Likewise, an important
aspect of the effort associated with maintaining knowledge bases is deciding
what information is no longer useful; pieces of information (such as
intelligence reports) may be outdated, may come from sources that have recently
been discovered to be of low quality, or abundant evidence may be available
that contradicts them. In this paper, we propose a probabilistic structured
argumentation framework that arises from the extension of Presumptive
Defeasible Logic Programming (PreDeLP) with probabilistic models, and argue
that this formalism is capable of addressing the basic issues of handling
contradictory and uncertain data. Then, to address the last issue, we focus on
the study of non-prioritized belief revision operations over probabilistic
PreDeLP programs. We propose a set of rationality postulates -- based on
well-known ones developed for classical knowledge bases -- that characterize
how such operations should behave, and study a class of operators along with
theoretical relationships with the proposed postulates, including a
representation theorem stating the equivalence between this class and the class
of operators characterized by the postulates.


title:
Nucleon Form Factors with 2+1 Flavors of Domain Wall Fermions and
  All-Mode-Averaging

abstract:
  We report recent progress in the calculations of the isovector nucleon
electromagnetic form factors using 2+1 flavors of domain wall fermions at pion
masses of 170 MeV and 250 MeV. The lattice size is fixed at $32^3\times64$ with
a lattice cutoff scale of 1.37(1) GeV. For the calculations with $M_\pi = 170$
MeV, we employed the All-Mode-Averaging (AMA) technique, which led to roughly a
factor of 20 improvement in computational efficiency and has reduced the
statistical errors in our results significantly. We were also able to do
calculations at two different source-sink separations, at roughly 1.3 fm and
1.0 fm, without much additional cost by reusing the low eigen-modes stored for
the AMA calculations. We will present results for the isovector form factors
and their derived quantities, including the Dirac and Pauli radii, anomalous
magnetic moment and discuss the effects of possible excited-state
contaminations. Connected contributions to the isoscalar Dirac and Pauli form
factors will also be shown.


title: On the Complexity of Randomly Weighted Voronoi Diagrams

abstract:
  In this paper, we provide an $O(n \mathrm{polylog} n)$ bound on the expected
complexity of the randomly weighted Voronoi diagram of a set of $n$ sites in
the plane, where the sites can be either points, interior-disjoint convex sets,
or other more general objects. Here the randomness is on the weight of the
sites, not their location. This compares favorably with the worst case
complexity of these diagrams, which is quadratic. As a consequence we get an
alternative proof to that of Agarwal etal [AHKS13] of the near linear
complexity of the union of randomly expanded disjoint segments or convex sets
(with an improved bound on the latter). The technique we develop is elegant and
should be applicable to other problems.


title:
Humidity effects on tip-induced polarization switching in lithium
  niobate

abstract:
  Interest to ferroelectric materials has been increased significantly in last
decades due to development of new generation of nonlinear optical and data
storage devices. Scanning probe microscopy (SPM) can be used both for study of
domain structures with nanoscale spatial resolution and for writing the
isolated nanodomains by local application of the electric field. Tip-induced
switching in the ambient still needs experimental investigations and
theoretical explorations. Here we studied influence of the value of relative
humidity in the SPM chamber on the process of tip-induced polarization
switching. This phenomenon was attributed to existing of the water meniscus
between tip and the sample surface in humid atmosphere. Presented results are
important for further complex investigations of the ferroelectric materials and
their applications.


title: Multilevel Pricing Schemes in a Deregulated Wireless Network Market

abstract:
  Typically the cost of a product, a good or a service has many components.
Those components come from different complex steps in the supply chain of the
product from sourcing to distribution. This economic point of view also takes
place in the determination of goods and services in wireless networks. Indeed,
before transmitting customer data, a network operator has to lease some
frequency range from a spectrum owner and also has to establish agreements with
electricity suppliers. The goal of this paper is to compare two pricing
schemes, namely a power-based and a flat rate, and give a possible explanation
why flat rate pricing schemes are more common than power based pricing ones in
a deregulated wireless market. We suggest a hierarchical game-theoretical model
of a three level supply chain: the end users, the service provider and the
spectrum owner. The end users intend to transmit data on a wireless network.
The amount of traffic sent by the end users depends on the available frequency
bandwidth as well as the price they have to pay for their transmission. A
natural question arises for the service provider: how to design an efficient
pricing scheme in order to maximize his profit. Moreover he has to take into
account the lease charge he has to pay to the spectrum owner and how many
frequency bandwidth to rent. The spectrum owner itself also looks for
maximizing its profit and has to determine the lease price to the service
provider. The equilibrium at each level of our supply chain model are
established and several properties are investigated. In particular, in the case
of a power-based pricing scheme, the service provider and the spectrum owner
tend to share the gross provider profit. Whereas, considering the flat rate
pricing scheme, if the end users are going to exploit the network intensively,
then the tariffs of the suppliers (spectrum owner and service provider)
explode.


title:
Lower Bounds and Approximations for the Information Rate of the ISI
  Channel

abstract:
  We consider the discrete-time intersymbol interference (ISI) channel model,
with additive Gaussian noise and fixed i.i.d. inputs. In this setting, we
investigate the expression put forth by Shamai and Laroia as a conjectured
lower bound for the input-output mutual information after application of a
MMSE-DFE receiver. A low-SNR expansion is used to prove that the conjectured
bound does not hold under general conditions, and to characterize inputs for
which it is particularly ill-suited. One such input is used to construct a
counterexample, indicating that the Shamai-Laroia expression does not always
bound even the achievable rate of the channel, thus excluding a natural
relaxation of the original conjectured bound. However, this relaxed bound is
then shown to hold for any finite entropy input and ISI channel, when the SNR
is sufficiently high. Finally, new simple bounds for the achievable rate are
proven, and compared to other known bounds. Information-Estimation relations
and estimation-theoretic bounds play a key role in establishing our results.


title: Quantum tomography meets dynamical systems and bifurcations theory

abstract:
  A powerful tool for studying geometrical problems in Hilbert space is
developed. In particular, we study the quantum pure state tomography problem in
finite dimensions from the point of view of dynamical systems and bifurcations
theory. First, we introduce a generalization of the Hellinger metric for
probability distributions which allows us to find a geometrical interpretation
of the quantum state tomography problem. Thereafter, we prove that every
solution to the state tomography problem is an attractive fixed point of the
so-called physical imposition operator. Additionally, we demonstrate that
multiple states corresponding to the same experimental data are associated to
bifurcations of this operator. Such a kind of bifurcations only occurs when
informationally incomplete set of observables are considered. Finally, we prove
that the physical imposition operator has a non-contractive Lipschitz constant
2 for the Bures metric. This value of the Lipschitz constant manifests the
existence of the quantum tomography problem for pure states.


title: SU(5) Octet Scalar at the LHC

abstract:
  Color scalars are salient features of non-minimal SU(5) model, where Higgs
sector is extended by 45-dimensional multiplet. We show that gauge coupling
unification can be realized in this model with TeV octet scalar and
intermediate (~10^6 GeV) color-triplet scalar at scale larger than 10^{15} GeV.
We analyze the possible LHC signatures of these TeV octet scalars. We emphasize
that multi-(b)-jet final states provide significant signal for direct probe of
octet scalars at the LHC.


title:
On the $p$-version of FEM in one dimension: The known and unknown
  features

abstract:
  The paper analyses the convergence of the $p$-version of the FEM when the
solution is piecewise analytic function. It focuses on pointwise convergence of
the gradient. It shows that at boundary the rate is different than inside the
element and there is a Gibbs phenomenon in the neighborhood of the point where
the solution is not analytic. The major result is a conjecture written in the
form of a theorem. The conjecture is based on careful numerical computations.
The known theoretical results are stated.


title: Monotone-light factorisation systems and torsion theories

abstract:
  Given a torsion theory (Y,X) in an abelian category C, the reflector I from C
to the torsion-free subcategory X induces a reflective factorisation system (E,
M) on C. It was shown by A. Carboni, G.M. Kelly, G. Janelidze and R. Par\'e
that (E, M) induces a monotone-light factorisation system (E',M*) by
simultaneously stabilising E and localising M, whenever the torsion theory is
hereditary and any object in C is a quotient of an object in X. We extend this
result to arbitrary normal categories, and improve it also in the abelian case,
where the heredity assumption on the torsion theory turns out to be redundant.
Several new examples of torsion theories where this result applies are then
considered in the categories of abelian groups, groups, topological groups,
commutative rings, and crossed modules.


title: Noncommutativity in the early Universe

abstract:
  In the present work, we study the noncommutative version of a quantum
cosmology model. The model has a Friedmann-Robertson-Walker geometry, the
matter content is a radiative perfect fluid and the spatial sections have zero
constant curvature. In this model the scale factor takes values in a bounded
domain. Therefore, its quantum mechanical version has a discrete energy
spectrum. We compute the discrete energy spectrum and the corresponding
eigenfunctions. The energies depend on a noncommutative parameter $\beta$. We
compute the scale factor expected value ($\left<a\right>$) for several values
of $\beta$. For all of them, $\left<a\right>$ oscillates between maxima and
minima values and never vanishes. It gives an initial indication that those
models are free from singularities, at the quantum level. We improve this
result by showing that if we subtract a quantity proportional to the standard
deviation of $a$ from $\left<a\right>$, this quantity is still positive. The
$\left<a\right>$ behavior, for the present model, is a drastic modification of
the $\left<a\right>$ behavior in the corresponding commutative version of the
present model. There, $\left<a\right>$ grows without limits with the time
variable. Therefore, if the present model may represent the early stages of the
Universe, the results of the present paper give an indication that
$\left<a\right>$ may have been, initially, bounded due to noncommutativity. We
also compute the Bohmian trajectories for $a$, which are in accordance with
$\left<a\right>$, and the quantum potential $Q$. From $Q$, we may understand
why that model is free from singularities, at the quantum level.


title: Design & Development of the Graphical User Interface for Sindhi Language

abstract:
  This paper describes the design and implementation of a Unicode-based GUISL
(Graphical User Interface for Sindhi Language). The idea is to provide a
software platform to the people of Sindh as well as Sindhi diasporas living
across the globe to make use of computing for basic tasks such as editing,
composition, formatting, and printing of documents in Sindhi by using GUISL.
The implementation of the GUISL has been done in the Java technology to make
the system platform independent. The paper describes several design issues of
Sindhi GUI in the context of existing software tools and technologies and
explains how mapping and concatenation techniques have been employed to achieve
the cursive shape of Sindhi script.


title: Charmonium, $D_s$ and $D_s^*$ from overlap fermion on DWF configurations

abstract:
  We take a new approach to determine the scale parameter $r_0$, the physical
masses of strange and charm quarks through a global fit which incorporates
continuum extrapolation, chiral extrapolation and quark mass interpolation to
the lattice data. The charmonium and charm-strange meson spectrum are
calculated with overlap valence quarks on $2+1$-flavor domain-wall fermion
gauge configurations generated by the RBC and UKQCD Collaboration. We use the
masses of $D_s$, $D_s^*$ and $J/\psi$ as inputs and obtain $m_c^{\overline{\rm
MS}}(2\,{\rm GeV})=1.110(24)\,{\rm GeV}$, $m_s^{\overline{\rm MS}}(2\,{\rm
GeV})=0.104(9)\,{\rm GeV}$ and $r_0=0.458(11)\,{\rm fm}$. Subsequently, the
hyperfine-splitting of charmonium and $f_{D_s}$ are predicted to be
$112(5)\,{\rm MeV}$ and $254(5)\,{\rm MeV}$, respectively.


title: Forward and Inverse Kinematics Seamless Matching Using Jacobian

abstract:
  In this paper the problem of matching Forward Kinematics (FK) motion of a 3
Dimensional (3D) joint chain to the Inverse Kinematics (IK) movement and vice
versa has been addressed. The problem lies at the heart of animating a 3D
character having controller and manipulator based rig for animation within any
3D modeling and animation software. The seamless matching has been achieved
through the use of pseudo-inverse of Jacobian Matrix. The Jacobian Matrix is
used to determine the rotation values of each joint of character body part such
as arms, between the inverse kinematics and forward kinematics motion. Then
moving the corresponding kinematic joint system to the desired place,
automatically eliminating the jumping or popping effect which would reduce the
complexity of the system.


title:
Key point selection and clustering of swimmer coordination through
  Sparse Fisher-EM

abstract:
  To answer the existence of optimal swimmer learning/teaching strategies, this
work introduces a two-level clustering in order to analyze temporal dynamics of
motor learning in breaststroke swimming. Each level have been performed through
Sparse Fisher-EM, a unsupervised framework which can be applied efficiently on
large and correlated datasets. The induced sparsity selects key points of the
coordination phase without any prior knowledge.

categories: stat.ML cs.CV cs.LG physics.data-an stat.AP


title: Rank discriminants for predicting phenotypes from RNA expression

abstract:
  Statistical methods for analyzing large-scale biomolecular data are
commonplace in computational biology. A notable example is phenotype prediction
from gene expression data, for instance, detecting human cancers,
differentiating subtypes and predicting clinical outcomes. Still, clinical
applications remain scarce. One reason is that the complexity of the decision
rules that emerge from standard statistical learning impedes biological
understanding, in particular, any mechanistic interpretation. Here we explore
decision rules for binary classification utilizing only the ordering of
expression among several genes; the basic building blocks are then two-gene
expression comparisons. The simplest example, just one comparison, is the TSP
classifier, which has appeared in a variety of cancer-related discovery
studies. Decision rules based on multiple comparisons can better accommodate
class heterogeneity, and thereby increase accuracy, and might provide a link
with biological mechanism. We consider a general framework ("rank-in-context")
for designing discriminant functions, including a data-driven selection of the
number and identity of the genes in the support ("context"). We then specialize
to two examples: voting among several pairs and comparing the median expression
in two groups of genes. Comprehensive experiments assess accuracy relative to
other, more complex, methods, and reinforce earlier observations that simple
classifiers are competitive.


title:
Gradient-Driven Molecule Construction: An Inverse Approach Applied to
  the Design of Small-Molecule Fixating Catalysts

abstract:
  Rational design of molecules and materials usually requires extensive
screening of molecular structures for the desired property. The inverse
approach to deduce a structure for a predefined property would be highly
desirable, but is, unfortunately, not well-defined. However, feasible
strategies for such an inverse design process may be successfully developed for
specific purposes. We discuss options for calculating 'jacket' potentials that
fulfill a predefined target requirement - a concept that we recently introduced
[T. Weymuth, M. Reiher, MRS Proceediungs, 2013, 1524,
DOI:10.1557/opl.2012.1764]. We consider the case of small-molecule activating
transition metal catalysts. As a target requirement we choose the vanishing
geometry gradients on all atoms of a subsystem consisting of a metal center
binding the small molecule to be activated. The jacket potential can be
represented within a full quantum model or by a sequence of approximations of
which a field of electrostatic point charges is the simplest. In a second step,
the jacket potential needs to be replaced by a chemically viable chelate-ligand
structure for which the geometry gradients on all of its atoms are also
required to vanish. In order to analyze the feasibility of this approach, we
dissect a known dinitrogen-fixating catalyst to study possible design
strategies that must eventually produce the known catalyst.


title: Indication for unsmooth horizon induced by quantum gravity interaction

abstract:
  The angular ADM reduction of the BTZ spacetime yields a Liouville-type
theory. The analysis of the resulting Liouville theory naturally leads to
identification of the stretched horizon. The dynamics associated with the
stretched horizon has a feature that seems consistent with the unsmooth
horizon; the quantum gravity effects are essential for the unsmoothness. We
show that the "anomaly" term in the stress-energy tensor is responsible for the
Planck scale energy experienced by an infalling observer.


title: Two-dimensional phononic-photonic bandgap optomechanical crystal cavity

abstract:
  We present the fabrication and characterization of an artificial crystal
structure formed from a thin-film of silicon which has a full phononic bandgap
for microwave X-band phonons and a two-dimensional pseudo-bandgap for
near-infrared photons. An engineered defect in the crystal structure is used to
localize optical and mechanical resonances in the bandgap of the planar
crystal. Two-tone optical spectroscopy is used to characterize the cavity
system, showing a large vacuum coupling rate of 220kHz between the fundamental
optical cavity resonance at 195THz and a co-localized mechanical resonance at
9.3GHz.


title: Glueballs from the Lattice

abstract:
  Recent numerical calculations of the glueball spectrum in QCD, in SU($N$)
Yang-Mills theory in the large-$N$ limit and in candidate theories of strongly
interacting dynamics beyond the standard model (in which the lowest-lying
scalar plays the role of the Higgs boson) are reviewed and their implications
for our theoretical understanding of glueballs in QCD-like theories and in
strongly coupled gauge theories with a (near-)conformal dynamics are discussed.


title:
Direct measurement of the acoustic waves generated by femtosecond
  filaments in air

abstract:
  We present direct measurements of the gas acoustic dynamics following
interaction of spatial single- and multi-mode 50 fs, 800 nm pulses in air at 10
Hz and 1 kHz repetition rates. Results are in excellent agreement with
hydrodynamic simulations. Under no conditions for single filaments do we find
on-axis enhancement of gas density; this occurs only with multi-filaments. We
also investigate the propagation of probe beams in the gas density profile
induced by a single extended filament. We find that light trapping in the
expanding annular acoustic wave can create the impression of on-axis guiding in
a limited temporal window.


title:
Exotic magnetism on the quasi-FCC lattices of the $d^3$ double
  perovskites La$_2$NaB$'$O$_6$ (B$'$ $=$ Ru, Os)

abstract:
  We find evidence for long-range and short-range ($\zeta$ $=$ 70 \AA~at 4 K)
incommensurate magnetic order on the quasi-face-centered-cubic (FCC) lattices
of the monoclinic double perovskites La$_2$NaRuO$_6$ and La$_2$NaOsO$_6$
respectively. Incommensurate magnetic order on the FCC lattice has not been
predicted by mean field theory, but may arise via a delicate balance of
inequivalent nearest neighbour and next nearest neighbour exchange
interactions. In the Ru system with long-range order, inelastic neutron
scattering also reveals a spin gap $\Delta$ $\sim$ 2.75 meV. Magnetic
anisotropy is generally minimized in the more familiar octahedrally-coordinated
$3d^3$ systems, so the large gap observed for La$_2$NaRuO$_6$ may result from
the significantly enhanced value of spin-orbit coupling in this $4d^3$
material.


title: Halo model and halo properties in Galileon gravity cosmologies

abstract:
  We investigate the performance of semi-analytical modelling of large-scale
structure in Galileon gravity cosmologies using results from N-body
simulations. We focus on the Cubic and Quartic Galileon models that provide a
reasonable fit to CMB, SNIa and BAO data. We demonstrate that the Sheth-Tormen
mass function and linear halo bias can be calibrated to provide a very good fit
to our simulation results. We also find that the halo concentration-mass
relation is well fitted by a power law. The nonlinear matter power spectrum
computed in the halo model approach is found to be inaccurate in the mildly
nonlinear regime, but captures reasonably well the effects of the Vainshtein
screening mechanism on small scales. In the Cubic model, the screening
mechanism hides essentially all of the effects of the fifth force inside
haloes. In the case of the Quartic model, the screening mechanism leaves behind
residual modifications to gravity, which make the effective gravitational
strength time-varying and smaller than the standard value. Compared to normal
gravity, this causes a deficiency of massive haloes and leads to a weaker
matter clustering on small scales. For both models, we show that there are
realistic halo occupation distributions of Luminous Red Galaxies that can match
both the observed large-scale clustering amplitude and the number density of
these galaxies.


title:
Transport enhancement and suppression in turbulent magnetic
  reconnection: A self-consistent turbulence model

abstract:
  Through the enhancement of transport, turbulence is expected to contribute to
the fast reconnection. However the effects of turbulence are not so
straightforward. In addition to the enhancement of transport, turbulence under
some environment shows effects that suppress the transport. In the presence of
turbulent cross helicity, such a dynamic balance between the transport
enhancement and suppression occurs. As this result of dynamic balance, the
region of effective enhanced magnetic diffusivity is confined to a narrow
region, leading to the fast reconnection. In order to confirm this idea, a
self-consistent turbulence model for the magnetic reconnection is proposed.
With the aid of numerical simulations where turbulence effects are incorporated
in a consistent manner through the turbulence model, the dynamic balance in the
turbulence magnetic reconnection is confirmed.


title: The Atmospheres of Earth-like Planets after Giant Impact Events

abstract:
  It is now understood that the accretion of terrestrial planets naturally
involves giant collisions, the moon-forming impact being a well known example.
In the aftermath of such collisions the surface of the surviving planet is very
hot and potentially detectable. Here we explore the atmospheric chemistry,
photochemistry, and spectral signatures of post-giant-impact terrestrial
planets enveloped by thick atmospheres consisting predominantly of CO2, and
H2O. The atmospheric chemistry and structure are computed self-consistently for
atmospheres in equilibrium with hot surfaces with composition reflecting either
the bulk silicate Earth (which includes the crust, mantle, atmosphere and
oceans) or Earth's continental crust. We account for all major molecular and
atomic opacity sources including collision-induced absorption. We find that
these atmospheres are dominated by H2O and CO2, while the formation of CH4, and
NH3 is quenched due to short dynamical timescales. Other important constituents
are HF, HCl, NaCl, and SO2. These are apparent in the emerging spectra, and can
be indicative that an impact has occurred. The use of comprehensive opacities
results in spectra that are a factor of 2 lower in surface brightness in the
spectral windows than predicted by previous models. The estimated luminosities
show that the hottest post-giant-impact planets will be detectable with
near-infrared coronagraphs on the planned 30m-class telescopes. The 1-4um
region will be most favorable for such detections, offering bright features and
better contrast between the planet and a potential debris disk. We derive
cooling timescales on the order of 10^5-10^6 Myrs, based on the modeled
effective temperatures. This leads to the possibility of discovering tens of
such planets in future surveys.


title:
Emergent Fermi surfaces, fractionalization and duality in supersymmetric
  QED

abstract:
  We study the physics of 3d supersymmetric abelian gauge theories (with small
supersymmetry breaking perturbations) at finite density. Using mirror symmetry,
which provides a natural generalization of the duality between the XY model and
the abelian Higgs model but now including fermionic fields, we see many
dynamical phenomena conjectured to be of relevance in condensed matter systems.
In particular, we find examples of the emergence of a Fermi surface at low
energies from hybridization of fermions localized at magnetic defects at high
energies, as well as fractionalization of charged fermions into spinon-holon
pairs with the concomitant appearance of emergent gauge fields. We also find
dual descriptions for Fermi surfaces coupled to critical bosons, which give
rise to non-Fermi liquids.


title:
The SLUGGS Survey: Breaking degeneracies between dark matter, anisotropy
  and the IMF using globular cluster subpopulations in the giant elliptical NGC
  5846

abstract:
  We study the mass and anisotropy distribution of the giant elliptical galaxy
NGC 5846 using stars, as well as the red and blue globular cluster (GC)
subpopulations. We break degeneracies in the dynamical models by taking
advantage of the different phase space distributions of the two GC
subpopulations to unambiguously constrain the mass of the galaxy and the
anisotropy of the GC system. Red GCs show the same spatial distribution and
behaviour as the starlight, whereas blue GCs have a shallower density profile,
a larger velocity dispersion and a lower kurtosis, all of which suggest a
different orbital distribution. We use a dispersion-kurtosis Jeans analysis and
find that the solutions of separate analyses for the two GC subpopulations
overlap in the halo parameter space. The solution converges on a massive dark
matter halo, consistent with expectations from $\Lambda$CDM and WMAP7 cosmology
in terms of virial mass ($\log M_{DM} \sim13.3 M_{sun}$) and concentration
($c_{vir}\sim8$). This is the first such analysis that solves the dynamics of
the different GC subpopulations in a self-consistent manner. Our method
improves the uncertainties on the halo parameter determination by a factor of
two and opens new avenues for the use of elliptical galaxy dynamics as tests of
predictions from cosmological simulations. The implied stellar mass-to-light
ratio derived from the dynamical modelling is fully consistent with a Salpeter
initial mass function (IMF) and rules out a bottom light IMF. The different GC
subpopulations show markedly distinct orbital distributions at large radii,
with red GCs having an anisotropy parameter $\beta\sim0.4$ outside $\sim3R_e$,
and the blue GCs having $\beta\sim0.15$ at the same radii, while centrally
($\sim1R_e$) they are both isotropic. We discuss the implications of our
findings within the two-phase formation scenario for early-type galaxies.


title: Non-standard top substructure

abstract:
  The top quark, being the heaviest particle of the Standard Model, is a prime
candidate of where physics beyond the SM might currently hide before our eyes.
There are many natural extensions of the SM that rely on top compositeness, and
the top quark could follow the paradigm of revealing a substructure when it is
probed at high enough momentum transfers. Observing high $p_T$ top final states
naturally drives us towards boosted hadronic analyses that can be tackled
efficiently with jet substructure techniques. In this paper we analyse the
prospects of constraining exemplary non-standard QCD top interactions in this
kinematical regime. We correctly include QCD modifications to additional gluon
emission off the boosted top quark and keep track of the modified top tagging
efficiencies. We conclude that non-standard top QCD interactions can be
formidably constrained at the LHC 14 TeV. Experimental systematic uncertainties
are a major obstacle of the described measurement. Unless significantly
improved for the 14 TeV run, they will saturate the direct sensitivity to
non-resonant BSM top physics at luminosities of around 100/fb.


title:
Precise parameters for both white dwarfs in the eclipsing binary CSS
  41177

abstract:
  We present ULTRACAM photometry and X-Shooter spectroscopy of the eclipsing
double white dwarf binary CSS 41177, the only such system that is also a
double-lined spectroscopic binary. Combined modelling of the light curves and
radial velocities yield masses and radii for both white dwarfs without the need
to assume mass-radius relations. We find that the primary white dwarf has a
mass of M1 = 0.38(2) Msun and a radius of R1 = 0.0222(4) Rsun. The secondary
white dwarf's mass and radius are M2 = 0.32(1) Msun and R2 = 0.0207(4) Rsun,
and its temperature and surface gravity (T2 = 11678(313) K, log(g2) = 7.32(2))
put it close to the white dwarf instability strip. However, we find no evidence
for pulsations to roughly 0.5% relative amplitude. Both masses and radii are
consistent with helium white dwarf models with thin hydrogen envelopes of
0.0001 Mstar. The two stars will merge in 1.14 Gyr due to angular momentum loss
via gravitational wave emission.


title: Introductory notes on holographic superconductors

abstract:
  The purpose of these lecture notes is to give a quick and introductory
overview of holographic superconductors. Besides the actual description of the
standard holographic superconductor, attention is paid to the motivations and
the relation with the previous, non-holographic context.


title:
The PdBI Arcsecond Whirlpool Survey (PAWS): Environmental Dependence of
  Giant Molecular Cloud Properties in M51

abstract:
  Using data from the PdBI Arcsecond Whirlpool Survey (PAWS), we have generated
the largest extragalactic Giant Molecular Cloud (GMC) catalog to date,
containing 1,507 individual objects. GMCs in the inner M51 disk account for
only 54% of the total 12CO(1-0) luminosity of the survey, but on average they
exhibit physical properties similar to Galactic GMCs. We do not find a strong
correlation between the GMC size and velocity dispersion, and a simple virial
analysis suggests that 30% of GMCs in M51 are unbound. We have analyzed the GMC
properties within seven dynamically-motivated galactic environments, finding
that GMCs in the spiral arms and in the central region are brighter and have
higher velocity dispersions than inter-arm clouds. Globally, the GMC mass
distribution does not follow a simple power law shape. Instead, we find that
the shape of the mass distribution varies with galactic environment: the
distribution is steeper in inter-arm region than in the spiral arms, and
exhibits a sharp truncation at high masses for the nuclear bar region. We
propose that the observed environmental variations in the GMC properties and
mass distributions are a consequence of the combined action of large-scale
dynamical processes and feedback from high mass star formation. We describe
some challenges of using existing GMC identification techniques for decomposing
the 12CO(1-0) emission in molecule-rich environments, such as M51's inner disk.


title: Self-force via Green functions and worldline integration

abstract:
  A compact object moving in curved spacetime interacts with its own
gravitational field. This leads to both dissipative and conservative
corrections to the motion, which can be interpreted as a self-force acting on
the object. The original formalism describing this self-force relied heavily on
the Green function of the linear differential operator that governs
gravitational perturbations. However, because the global calculation of Green
functions in non-trivial black hole spacetimes has been an open problem until
recently, alternative methods were established to calculate self-force effects
using sophisticated regularization techniques that avoid the computation of the
global Green function. We present a method for calculating the self-force that
employs the global Green function and is therefore closely modeled after the
original self-force expressions. Our quantitative method involves two stages:
(i) numerical approximation of the retarded Green function in the background
spacetime; (ii) evaluation of convolution integrals along the worldline of the
object. This novel approach can be used along arbitrary worldlines, including
those currently inaccessible to more established computational techniques.
Furthermore, it yields geometrical insight into the contributions to
self-interaction from curved geometry (back-scattering) and trapping of null
geodesics. We demonstrate the method on the motion of a scalar charge in
Schwarzschild spacetime. This toy model retains the physical history-dependence
of the self-force but avoids gauge issues and allows us to focus on basic
principles. We compute the self-field and self-force for many worldlines
including accelerated circular orbits, eccentric orbits at the separatrix, and
radial infall. This method, closely modeled after the original formalism,
provides a promising complementary approach to the self-force problem.


title: Looking for the minimal inverse seesaw realisation

abstract:
  In this work we consider a simple extension of the Standard Model involving
additional fermionic singlets and assume an underlying inverse seesaw mechanism
(with one or more right-handed neutrinos and one or more sterile fermions) for
neutrino mass generation. Under the assumption that both sterile states and
right-handed neutrinos are present, our goal is to determine which is the
minimal inverse seesaw realisation that accounts for neutrino data while at the
same time complying with all experimental requirements (electroweak precision
tests and laboratory constraints). This study aims at identifying the minimal
inverse seesaw realisation for the 3-flavour and for the 3 +~more-mixing
schemes, the latter giving an explanation for the reactor anomalies and/or
providing a possible candidate for the dark matter of the Universe. Based on a
perturbative approach, our generic study shows that in the class of inverse
seesaw models giving rise to a 3-flavour flavour mixing scheme, only two mass
scales are relevant (the light neutrino mass scale, $m_\nu$ and the mass of the
right-handed neutrinos, $M_R$) while in the case of a 3 + 1-mixing scheme, an
additional mass scale ($\mu$ $\in[m_\nu,M_R]$) is required. For each of the two
obtained inverse seesaw frameworks, we conduct a thorough numerical analysis,
providing predictions for the hierarchy of the light neutrino spectrum and for
the effective mass in neutrinoless double beta decay.


title:
Measuring Distances and Reddenings for a Billion Stars: Towards A 3D
  Dust Map from Pan-STARRS 1

abstract:
  We present a method to infer reddenings and distances to stars, based only on
their broad-band photometry, and show how this method can be used to produce a
three-dimensional dust map of the Galaxy. Our method samples from the full
probability density function of distance, reddening and stellar type for
individual stars, as well as the full uncertainty in reddening as a function of
distance in the 3D dust map. We incorporate prior knowledge of the distribution
of stars in the Galaxy and the detection limits of the survey. For stars in the
Pan-STARRS 1 (PS1) 3 pi survey, we demonstrate that our reddening estimates are
unbiased, and accurate to ~0.13 mag in E(B-V) for the typical star. Based on
comparisons with mock catalogs, we expect distances for main-sequence stars to
be constrained to within ~20% - 60%, although this range can vary, depending on
the reddening of the star, the precise stellar type and its position on the
sky. A further paper will present a 3D map of dust over the three quarters of
the sky surveyed by PS1. Both the individual stellar inferences and the 3D dust
map will enable a wealth of Galactic science in the plane. The method we
present is not limited to the passbands of the PS1 survey, but may be extended
to incorporate photometry from other surveys, such as 2MASS, SDSS (where
available), and in the future, LSST and Gaia.


title:
Homoclinic connections with many loops near a $0^2 iw$ resonant fixed
  point for Hamiltonian systems

abstract:
  In this paper we study the dynamics near the equilibrium point of a family of
Hamiltonian systems in the neighborhood of a $0^2 iw$ resonance. The existence
of a family of periodic orbits surrounding the equilibrium is well-known and we
show here the existence of homoclinic connections with several loops for every
periodic orbit close to the origin, except the origin itself. To prove this
result, we first show a Hamiltonian normal form theorem inspired by the
Elphick-Tirapegui-Brachet-Coullet-Iooss normal form. We then use a local
Hamiltonian normalization relying on a result of Moser. We obtain the result of
existence of homoclinic orbits by geometrical arguments based on the low
dimension and with the aid of a KAM theorem which allows to confine the loops.
The same problem was studied before for reversible non Hamiltonian
vectorfields, and the splitting of the homoclinic orbits lead to exponentially
small terms which prevent the existence of homoclinic connections to
exponentially small periodic orbits. The same phenomenon occurs here but we get
round this difficulty thanks to geometric arguments specific to Hamiltonian
systems and by studying homoclinic orbits with many loops.


title: Sub-millimeter galaxies as progenitors of compact quiescent galaxies

abstract:
  Three billion years after the big bang (at redshift z=2), half of the most
massive galaxies were already old, quiescent systems with little to no residual
star formation and extremely compact with stellar mass densities at least an
order of magnitude larger than in low redshift ellipticals, their descendants.
Little is known about how they formed, but their evolved, dense stellar
populations suggest formation within intense, compact starbursts 1-2 Gyr
earlier (at 3<z<6). Simulations show that gas-rich major mergers can give rise
to such starbursts which produce dense remnants. Sub-millimeter selected
galaxies (SMGs) are prime examples of intense, gas-rich, starbursts. With a
new, representative spectroscopic sample of compact quiescent galaxies at z=2
and a statistically well-understood sample of SMGs, we show that z=3-6 SMGs are
consistent with being the progenitors of z=2 quiescent galaxies, matching their
formation redshifts and their distributions of sizes, stellar masses and
internal velocities. Assuming an evolutionary connection, their space densities
also match if the mean duty cycle of SMG starbursts is 42 (+40/-29) Myr
(consistent with independent estimates), which indicates that the bulk of stars
in these massive galaxies were formed in a major, early surge of
star-formation. These results suggests a coherent picture of the formation
history of the most massive galaxies in the universe, from their initial burst
of violent star-formation through their appearance as high stellar-density
galaxy cores and to their ultimate fate as giant ellipticals.


title: Notes on nonabelian (0,2) theories and dualities

abstract:
  In this paper we explore basic aspects of nonabelian (0,2) GLSM's in two
dimensions for unitary gauge groups, an arena that until recently has largely
been unexplored. We begin by discussing general aspects of (0,2) theories,
including checks of dynamical supersymmetry breaking, spectators and weak
coupling limits, and also build some toy models of (0,2) theories for bundles
on Grassmannians, which gives us an opportunity to relate physical anomalies
and trace conditions to mathematical properties. We apply these ideas to study
(0,2) theories on Pfaffians, applying recent perturbative constructions of
Pfaffians of Jockers et al. We discuss how existing dualities in (2,2)
nonabelian gauge theories have a simple mathematical understanding, and make
predictions for additional dualities in (2,2) and (0,2) gauge theories.
Finally, we outline how duality works in open strings in unitary gauge
theories, and also describe why, in general terms, we expect analogous
dualities in (0,2) theories to be comparatively rare.


title:
Inverse Quantum Chemistry: Concepts and Strategies for Rational Compound
  Design

abstract:
  The rational design of molecules and materials is becoming more and more
important. With the advent of powerful computer systems and sophisticated
algorithms, quantum chemistry plays an important role in rational design. While
traditional quantum chemical approaches predict the properties of a predefined
molecular structure, the goal of inverse quantum chemistry is to find a
structure featuring one or more desired properties. Herein, we review inverse
quantum chemical approaches proposed so far and discuss their advantages as
well as their weaknesses.


title:
On the Stability of Random Multiple Access with Feedback Exploitation
  and Queue Priority

abstract:
  In this paper, we study the stability of two interacting queues under random
multiple access in which the queues leverage the feedback information. We
derive the stability region under random multiple access where one of the two
queues exploits the feedback information and backs off under negative
acknowledgement (NACK) and the other, higher priority, queue will access the
channel with probability one. We characterize the stability region of this
feedback-based random access protocol and prove that this derived stability
region encloses the stability region of the conventional random access (RA)
scheme that does not exploit the feedback information.


title: An Elementary Proof of an Asymptotic Formula of Ramanujan

abstract:
  We derive the mean square of the divisor function using only elementary
techniques.


title:
Experimental investigation of the optical spin selection rules in bulk
  Si and Ge/Si quantum dots

abstract:
  We study the relationship between the circular polarization of
photoluminescence and the magnetic field-induced spin-polarization of the
recombining charge carriers in bulk Si and Ge/Si quantum dots. First, we
quantitatively compare experimental results on the degree of circular
polarization of photons resulting from phonon-assisted radiative transitions in
intrinsic and doped bulk Si with calculations which we adapt from recently
predicted spin-dependent phonon-assisted transition probabilities in Si. The
excellent agreement of our experiments and calculations quantitatively verifies
these spin-dependent transition probabilities and extends their validity to
weak magnetic fields. Such magnetic fields can induce a luminescence
polarization of up to 3%/T. We then investigate phononless transitions in Ge/Si
quantum dots as well as in degenerately doped Si. Our experiments
systematically show that the sign of the degree of circular polarization of
luminescence resulting from phononless transitions is opposite to the one
associated with phonon-assisted transitions in Si and with phononless
transitions in direct band gap semiconductors. This observation implies
qualitatively different spin-dependent selection rules for phononless
transitions, which seem to be related to the confined character of the electron
wave function.


title: Geometric spectra and commensurability

abstract:
  The work of Reid, Chinburg--Hamilton--Long--Reid, Prasad--Rapinchuk, and the
author with Reid have demonstrated that geodesics or totally geodesic
submanifolds can sometimes be used to determine the commensurability class of
an arithmetic manifold. The main results of this article show that
generalizations of these results to other arithmetic manifolds will require a
wide range of data. Specifically, we prove that certain incommensurable
arithmetic manifolds arising from the semisimple Lie groups of the form
$(\SL(d,\R))^r \times (\SL(d,\C))^s$ have the same commensurability classes of
totally geodesic submanifolds coming from a fixed field. This construction is
algebraic and shows the failure of determining, in general, a central simple
algebra from subalgebras over a fixed field. This, in turn, can be viewed in
terms of forms of $\SL_d$ and the failure of determining the form via certain
classes of algebraic subgroups.


title:
Transitions and excitations in a superfluid stream passing small
  impurities

abstract:
  We analyse asymptotically and numerically the motion around a single impurity
and a network of impurities inserted in a two-dimensional superfluid. The
criticality for the break down of superfluidity is shown to occur when it
becomes energetically favourable to create a doublet - the limiting case
between a vortex pair and a rarefaction pulse on the surface of the impurity.
Depending on the characteristics of the potential representing the impurity
different excitation scenarios are shown to exist for a single impurity as well
as for a lattice of impurities. Depending on the lattice characteristics it is
shown that several regimes are possible: dissipationless flow, excitations
emitted by the lattice boundary, excitations created in the bulk and the
formation of large scale structures.


title:
Abundance Patterns in the Interstellar Medium of Early-type Galaxies
  Observed with Suzaku

abstract:
  We have analyzed 17 early-type galaxies, 13 ellipticals and 4 S0's, observed
with Suzaku, and investigated metal abundances (O, Mg, Si, and Fe) and
abundance ratios (O/Fe, Mg/Fe, and Si/Fe) in the interstellar medium (ISM). The
emission from each on-source region, which is 4 times effective radius, r_e, is
reproduced with one- or two- temperature thermal plasma models as well as a
multi-temperature model, using APEC plasma code v2.0.1. The multi-temperature
model gave almost the same abundances and abundance ratios with the 1T or 2T
models. The weighted averages of the O, Mg, Si, and Fe abundances of all the
sample galaxies derived from the multi-temperature model fits are 0.83+-0.04,
0.93+-0.03, 0.80+-0.02, and 0.80+-0.02 solar, respectively, in solar units
according to the solar abundance table by Lodders (2003). These abundances show
no significant dependence on the morphology and environment. The systematic
differences in the derived metal abundances between the version 2.0.1 and 1.3.1
of APEC plasma codes were investigated. The derived O and Mg abundances in the
ISM agree with the stellar metallicity within a aperture with a radius of one
r_e derived from optical spectroscopy. From these results, we discuss the past
and present SN Ia rates and star formation histories in early-type galaxies.