title:
Regularized rank-based estimation of high-dimensional nonparanormal
  graphical models

abstract:
  A sparse precision matrix can be directly translated into a sparse Gaussian
graphical model under the assumption that the data follow a joint normal
distribution. This neat property makes high-dimensional precision matrix
estimation very appealing in many applications. However, in practice we often
face nonnormal data, and variable transformation is often used to achieve
normality. In this paper we consider the nonparanormal model that assumes that
the variables follow a joint normal distribution after a set of unknown
monotone transformations. The nonparanormal model is much more flexible than
the normal model while retaining the good interpretability of the latter in
that each zero entry in the sparse precision matrix of the nonparanormal model
corresponds to a pair of conditionally independent variables. In this paper we
show that the nonparanormal graphical model can be efficiently estimated by
using a rank-based estimation scheme which does not require estimating these
unknown transformation functions. In particular, we study the rank-based
graphical lasso, the rank-based neighborhood Dantzig selector and the
rank-based CLIME. We establish their theoretical properties in the setting
where the dimension is nearly exponentially large relative to the sample size.
It is shown that the proposed rank-based estimators work as well as their
oracle counterparts defined with the oracle data. Furthermore, the theory
motivates us to consider the adaptive version of the rank-based neighborhood
Dantzig selector and the rank-based CLIME that are shown to enjoy graphical
model selection consistency without assuming the irrepresentable condition for
the oracle and rank-based graphical lasso. Simulated and real data are used to
demonstrate the finite performance of the rank-based estimators.


title: S5 0716+714 : GeV variability study

abstract:
  The GeV observations by Fermi-LAT give us the opportunity to characterize the
high-energy emission (100 MeV - 300 GeV) variability properties of the BL Lac
object S5 0716+714. In this study, we performed flux and spectral analysis of
more than 3 year long (August 2008 to April 2012) Fermi-LAT data of the source.
During this period, the source exhibits two different modes of flux variability
with characteristic timescales of ~75 and ~140 days, respectively. We also
notice that the flux variations are characterized by a weak spectral hardening.
The GeV spectrum of the source shows a clear deviation from a simple power law,
and is better explained by a broken power law. Similar to other bright Fermi
blazars, the break energy does not vary with the source flux during the
different activity states. We discuss several possible scenarios to explain the
observed spectral break.


title:
Rapid Variability: What do we learn from correlated mm-/gamma-ray
  variability in jets ?

abstract:
  Densely time sampled multi-frequency flux measurements of the extreme BL Lac
object S5 0716+714 over the past three years allow us to study its broad-band
variability, and the detailed underlying physics, with emphasis on the location
and size of the emitting regions and the evolution with time. We study the
characteristics of some prominent mm-/gamma-ray flares in the context of the
shock-in-jet model and investigate the location of the high energy emission
region. The rapid rise and decay of the radio flares is in agreement with the
formation of a shock and its evolution, if a geometrical variation is included
in addition to intrinsic variations of the source. We find evidence for a
correlation between flux variations at gamma-ray and radio frequencies. A two
month time-delay between gamma-ray and radio flares indicates a non-cospatial
origin of gamma-rays and radio flux variations in S5 0716+714.


title: An Energy-Aware Protocol for Self-Organizing Heterogeneous LTE Systems

abstract:
  This paper studies the problem of self-organizing heterogeneous LTE systems.
We propose a model that jointly considers several important characteristics of
heterogeneous LTE system, including the usage of orthogonal frequency division
multiple access (OFDMA), the frequency-selective fading for each link, the
interference among different links, and the different transmission capabilities
of different types of base stations. We also consider the cost of energy by
taking into account the power consumption, including that for wireless
transmission and that for operation, of base stations and the price of energy.
Based on this model, we aim to propose a distributed protocol that improves the
spectrum efficiency of the system, which is measured in terms of the weighted
proportional fairness among the throughputs of clients, and reduces the cost of
energy. We identify that there are several important components involved in
this problem. We propose distributed strategies for each of these components.
Each of the proposed strategies requires small computational and
communicational overheads. Moreover, the interactions between components are
also considered in the proposed strategies. Hence, these strategies result in a
solution that jointly considers all factors of heterogeneous LTE systems.
Simulation results also show that our proposed strategies achieve much better
performance than existing ones.


title: Viral spread with or without emotions in online community

abstract:
  Diffusion of information and viral content, social contagion and influence
are still topics of broad evaluation. We have studied the information epidemic
in a social networking platform in order compare different campaign setups. The
goal of this work is to present the new knowledge obtained from studying two
artificial (experimental) and one natural (where people act emotionally) viral
spread that took place in a closed virtual world. We propose an approach to
modeling the behavior of online community exposed on external impulses as an
epidemic process. The presented results base on online multilayer system
observation, and show characteristic difference between setups, moreover, some
important aspects of branching processes are presented. We run experiments,
where we introduced viral to system and agents were able to propagate it. There
were two modes of experiment: with or without award. Dynamic of spreading both
of virals were described by epidemiological model and diffusion. Results of
experiments were compared with real propagation process - spontaneous
organization against ACTA. During general-national protest against new
antypiracy multinational agreement - ACTA, criticized for its adverse effect on
e.g. freedom of expression and privacy of communication, members of chosen
community could send a viral such as Stop-ACTA transparent. In this scenario,
we are able to capture behavior of society, when real emotions play a role, and
compare results with artificiality conditioned experiments. Moreover, we could
measure effect of emotions in viral propagation. As theory explaining the role
of emotions in spreading behaviour as an factor of message targeting and
individuals spread emotional-oriented content in a more carefully and more
influential way, the experiments show that probabilities of secondary
infections are four times bigger if emotions play a role.


title:
Asymptotic spectral gap and Weyl law for Ruelle resonances of open
  partially expanding maps

abstract:
  We consider a simple model of an open partially expanding map. Its trapped
set K in phase space is a fractal set. We first show that there is a well
defined discrete spectrum of Ruelle resonances which describes the asymptotics
of correlation functions for large time and which is parametrized by the
Fourier component \nu on the neutral direction of the dynamics. We introduce a
specific hypothesis on the dynamics that we call "minimal captivity". This
hypothesis is stable under perturbations and means that the dynamics is
univalued on a neighborhood of K. Under this hypothesis we show the existence
of an asymptotic spectral gap and a Fractal Weyl law for the upper bound of
density of Ruelle resonances in the semiclassical limit \nu -> infinity. Some
numerical computations with the truncated Gauss map illustrate these results.


title: Timelike Compton Scattering at JLab

abstract:
  It is demonstrated, that with exclusive final state, data from electron
scattering experiments that are recorded with loose trigger requirements can be
used to analyze photoproduction reactions. A preliminary results on Timelike
Compton Scattering using the electroproduction data from the CLAS detector at
Jefferson Lab are presented. In particular, using final state (pe-e+)
photoproduction of vector mesons and timelike photon is studied. Angular
asymmetries in Timelike Compton Scattering region is compared with model
predictions in the framework of Generalized Parton Distribution.


title: An autonomous and reversible Maxwell's demon

abstract:
  Building on a model introduced by Mandal and Jarzynski [Proc. Natl. Acad.
Sci. U. S. A., {\bf 109}, (2012) 11641], we present a simple version of an
autonomous reversible Maxwell's demon. By changing the entropy of a tape
consisting of a sequence of bits passing through the demon, the demon can lift
a mass using the coupling to a heat bath. Our model becomes reversible by
allowing the tape to move in both directions. In this thermodynamically
consistent model, total entropy production consists of three terms one of which
recovers the irreversible limit studied by MJ. Our demon allows an
interpretation in terms of an enzyme transporting and transforming molecules
between compartments. Moreover, both genuine equilibrium and a linear response
regime with corresponding Onsager coefficients are well defined. Efficiency and
efficiency at maximum power are calculated. In linear response, the latter is
shown to be bounded by 1/2 if the demon operates as a machine and by 1/3 if it
is operated as an eraser.


title:
Magnetism and Verwey transition in magnetite nanoparticles in thin
  polymer film

abstract:
  Magnetic and structural properties of magnetite nanoparticles stabilized in
polyvinyl-alcohol thin films are investigated by using X-ray diffraction (XRD),
transmission electron microscopy (TEM), electron paramagnetic resonance (EPR)
and static magnetometry techniques. The nanoparticles have well-defined
crystallinity, and are superparamagnetic at room temperature. Their size
distribution is characterized by the distinct log-normal law (with average
diameters near 5-7 nm) and slight maximum near 70-80 nm. The EPR spectra and
static magnetization data demonstrated pronounced anomalies in the interval
between 130 K (corresponding to Verwey transition) and 200 K. The experimental
data obtained can be understood on the basis of the half-metallic electronic
structure, complex temperature behavior of the magnetic anisotropy, along with
effects of "weak magnetic-electron" sublattice of magnetite.


title: Minimum-Link Paths Revisited

abstract:
  A path or a polygonal domain is C-oriented if the orientations of its edges
belong to a set of C given orientations; this is a generalization of the
notable rectilinear case (C = 2). We study exact and approximation algorithms
for minimum-link C-oriented paths and paths with unrestricted orientations,
both in C-oriented and in general domains. Our two main algorithms are as
follows:
  A subquadratic-time algorithm with a non-trivial approximation guarantee for
general (unrestricted-orientation) minimum-link paths in general domains.
  An algorithm to find a minimum-link C-oriented path in a C-oriented domain.
Our algorithm is simpler and more time-space efficient than the prior
algorithm.
  We also obtain several related results:
  - 3SUM-hardness of determining the link distance with unrestricted
orientations (even in a rectilinear domain).
  - An optimal algorithm for finding a minimum-link rectilinear path in a
rectilinear domain. The algorithm and its analysis are simpler than the
existing ones.
  - An extension of our methods to find a C-oriented minimum-link path in a
general (not necessarily C-oriented) domain.
  - A more efficient algorithm to compute a 2-approximate C-oriented
minimum-link path.
  - A notion of "robust" paths. We show how minimum-link C-oriented paths
approximate the robust paths with unrestricted orientations to within an
additive error of 1.


title:
Efficient parallel coordinate descent algorithm for convex optimization
  problems with separable constraints: application to distributed MPC

abstract:
  In this paper we propose a parallel coordinate descent algorithm for solving
smooth convex optimization problems with separable constraints that may arise
e.g. in distributed model predictive control (MPC) for linear network systems.
Our algorithm is based on block coordinate descent updates in parallel and has
a very simple iteration. We prove (sub)linear rate of convergence for the new
algorithm under standard assumptions for smooth convex optimization. Further,
our algorithm uses local information and thus is suitable for distributed
implementations. Moreover, it has low iteration complexity, which makes it
appropriate for embedded control. An MPC scheme based on this new parallel
algorithm is derived, for which every subsystem in the network can compute
feasible and stabilizing control inputs using distributed and cheap
computations. For ensuring stability of the MPC scheme, we use a terminal cost
formulation derived from a distributed synthesis. Preliminary numerical tests
show better performance for our optimization algorithm than other existing
methods.


title:
The GAPS Programme with HARPS-N@TNG II: No giant planets around the
  metal-poor star HIP 11952

abstract:
  In the context of the program Global Architecture of Planetary Systems
(GAPS), we have performed radial velocity monitoring of the metal-poor star HIP
11952 on 35 nights over about 150 days using the newly installed high
resolution spectrograph HARPS-N at the TNG and HARPS at ESO 3.6m telescope. The
radial velocities show a scatter of 7 m/s, compatible with the measurement
errors for such a moderately warm metal-poor star (Teff = 6040+-120K; [Fe/H]
=-1.9+-0.1). We then exclude the presence of the two giant planets with periods
of 6.95+-0.01 d and 290.0+-16.2 d and radial velocity semi-amplitudes of
100.3+-19.4 m/s and 105.2+-14.7 m/s, respectively, which had recently been
announced. This result is important considering that HIP 11952 was thought to
be the most metal-poor star hosting a planetary system with giant planets, thus
challenging some models of planet formation.


title: Rhombic preordering on a square substrate

abstract:
  A competition of incommensurate symmetries occurs whenever a system is forced
to conform to an ordering that is different from the intrinsically preferred
structure of the system itself. As a model system of such a competition, we
study the rivalry between the triangular ordering of hard disks and the square
symmetry induced by a periodic square substrate. By using density functional
theory as well as Monte Carlo computer simulations, we determine the full phase
behavior for the case of one particle per minimum. We observe a rhombic
preordering structure preceding the hexagonal solid as a direct consequence of
the competing symmetries. Furthermore, the square-rhombic transition is
reentrant with increasing substrate interaction. Our predictions can be
verified in experiments of colloids in laser fields.


title:
Sixth-order and Seventh-order Iterative Methods for Solving Nonlinear
  Equations

abstract:
  In this article, we discuss sixth-order and seventh-order iterative methods
for nonlinear equations. Derivative-based and derivative-free, both categories
are presented for said iterative methods. Especially sixth-order
derivative-based and derivative-free iterative families are constructed in such
a way that they circumstance a wide class of sixth-order methods which are
developed in last many years. Weight functions are introduced to enhance the
efficiency and parametric combination gives weight-age flexibility in between
weight functions.


title:
Core-shell multi-quantum wells in ZnO / ZnMgO nanowires with high
  optical efficiency at room temperature

abstract:
  Nanowire-based light-emitting devices require multi-quantum well
heterostructures with high room temperature optical efficiencies. We
demonstrate that such efficiencies can be attained through the use of
ZnO/Zn(1-x)MgxO core shell quantum well heterostructures grown by metal organic
vapour phase epitaxy. Varying the barrier Mg concentration from x=0.15 to x=0.3
leads to the formation of misfit induced dislocations in the multi quantum
wells. Correlatively, temperature dependant photoluminescence reveals that the
radial well luminescence intensity decreases much less rapidly with increasing
temperature for the lower Mg concentration. Indeed, about 54% of the 10K
intensity is retained at room temperature with x=0.15, against 2% with x=0.30.
Those results open the way to the realization of high optical efficiency
nanowire-based light emitting diodes.


title: On the self-decomposability of the Fr\'echet distribution

abstract:
  Let $\{\Gamma_t, \, t\ge 0\}$ be the Gamma subordinator. Using a moment
identification due to Bertoin-Yor (2002), we observe that for every $t > 0$ and
$\alpha\in (0,1)$ the random variable $\Gamma_t^{-\alpha}$ is distributed as
the exponential functional of some spectrally negative L\'evy process. This
entails that all size-biased samplings of Fr\'echet distributions are
self-decomposable and that the extreme value distribution $F_\xi$ is infinitely
divisible if and only if $\xi\not\in (0,1),$ solving problems raised by Steutel
(1973) and Bondesson (1992). We also review different analytical and
probabilistic interpretations of the infinite divisibility of
$\Gamma_t^{-\alpha}$ for $t,\alpha > 0.$


title:
Application of a smoothing technique to decomposition in convex
  optimization

abstract:
  Dual decomposition is a powerful technique for deriving decomposition schemes
for convex optimization problems with separable structure. Although the
Augmented Lagrangian is computationally more stable than the ordinary
Lagrangian, the prox-term destroys the separability of the given problem. In
this paper we use another approach to obtain a smooth Lagrangian, based on a
smoothing technique developed by Nesterov, which preserves separability of the
problem. With this approach we derive a new decomposition method, called
proximal center algorithm, which from the viewpoint of efficiency estimates
improves the bounds on the number of iterations of the classical dual gradient
scheme by an order of magnitude. This can be achieved with the new
decomposition algorithm since the resulting dual function has good smoothness
properties and since we make use of the particular structure of the given
problem.


title: Computing the torsion of the $p$-ramified module

abstract:
  We fix a prime number $p$ and $\K$ a number field, we denote by $M$ the
maximal abelian $p$-extension of $\Ko$ unramified outside $p$. The aim of this
paper is to study the $\Z_p$-module $\gal(M/\Ko)$ and to give a method to
effectively compute its structure as a $\Z_p$-module. Then we give numerical
results, for real quadratic fields, together with interpretations via
Cohen-Lenstra's heuristics.


title: Tensile effective stresses in hydrocarbon storage caverns

abstract:
  The "no-tensile effective stress" criterion is discussed. It is proven that
effective tensile stresses can be generated at a cavern wall after a rapid
increase or decrease in pressure. The Etzel K-102 test, performed in Germany
more than 20 years ago, is revisited using the notion of effective tensile
stresses.


title:
Trend prediction in temporal bipartite networks: the case of Movielens,
  Netflix, and Digg

abstract:
  Online systems where users purchase or collect items of some kind can be
effectively represented by temporal bipartite networks where both nodes and
links are added with time. We use this representation to predict which items
might become popular in the near future. Various prediction methods are
evaluated on three distinct datasets originating from popular online services
(Movielens, Netflix, and Digg). We show that the prediction performance can be
further enhanced if the user social network is known and centrality of
individual users in this network is used to weight their actions.


title:
Categorifications of the extended affine Hecke algebra and the affine
  q-Schur algebra S(n,r) for 2 < r < n

abstract:
  We categorify the extended affine Hecke algebra and the affine quantum Schur
algebra S(n,r) for 2 < r < n, using Elias-Khovanov and Khovanov-Lauda type
diagrams. We also define the affine analogue of the Elias-Khovanov and the
Khovanov-Lauda 2-representations of these categorifications into an extension
of the 2-category of affine (singular) Soergel bimodules.


title:
Parallel and distributed optimization methods for estimation and control
  in networks

abstract:
  System performance for networks composed of interconnected subsystems can be
increased if the traditionally separated subsystems are jointly optimized.
Recently, parallel and distributed optimization methods have emerged as a
powerful tool for solving estimation and control problems in large-scale
networked systems. In this paper we review and analyze the
optimization-theoretic concepts of parallel and distributed methods for solving
coupled optimization problems and demonstrate how several estimation and
control problems related to complex networked systems can be formulated in
these settings. The paper presents a systematic framework for exploiting the
potential of the decomposition structures as a way to obtain different parallel
algorithms, each with a different tradeoff among convergence speed, message
passing amount and distributed computation architecture. Several specific
applications from estimation and process control are included to demonstrate
the power of the approach.


title: Apostol-Euler polynomials arising from umbral calculus

abstract:
  In this paper, by using the orthogonality type as defined in the umbral
calculus, we derive explicit formula for several well known polynomials as a
linear combination of the Apostol-Euler polynomials.


title:
Proceedings 14th International Workshop on Verification of
  Infinite-State Systems

abstract:
  This volume contains the proceedings of Infinity'12, the 14th International
Workshop on Verification of Infinite-State Systems, which was held in Paris,
France on the 27th of August 2012 as a satellite event of FM'12. The aim of the
INFINITY workshop is to provide a forum for researchers interested in the
development of formal methods and algorithmic techniques for the analysis of
systems with infinitely many states, and their application in automated
verification of complex software and hardware systems.


title:
Sounds good? Determination of a gas/brine interface by an acoustic
  method at Manosque

abstract:
  Water hammers commonly are observed at wellheads and often are considered a
potential hazard that should be avoided. Nevertheless, there are a few
situations in which water hammers provide very valuable information about a
well. A comprehensive data-acquisition and analysis system has been developed
by Brouard Consulting and Ecole Polytechnique. One potential application of
that system is determining the depth of an interface between two fluids. This
application has been tested successfully at the Manosque field. It is
demonstrated here how this low-cost and non-intrusive system can be accurate
and allows practical, real-time measurements.


title:
Existence of Weak Solutions for a Diffuse Interface Model of
  Non-Newtonian Two-Phase Flows

abstract:
  We consider a phase field model for the flow of two partly miscible
incompressible, viscous fluids of Non-Newtonian (power law) type. In the model
it is assumed that the densities of the fluids are equal. We prove existence of
weak solutions for general initial data and arbitrarily large times with the
aid of a parabolic Lipschitz truncation method, which preserves solenoidal
velocity fields and was recently developed by Breit, Diening, and Schwarzacher.


title:
Long transient dynamics in the Anderson-Holstein model out of
  equilibrium

abstract:
  We calculate the time dependent nonequilibrium current through a single level
quantum dot strongly coupled to a vibrational mode. The nonequilibrium real
time dynamics caused by an instantaneous coupling of the leads to the quantum
dot is discussed using an approximate method. The approach, which is specially
designed for the strong polaronic regime, is based on the so-called polaron
tunneling approximation. Considering different initial dot occupations, we show
that a common steady state is reached after times much larger than the typical
electron tunneling times due to a polaron blocking effect in the dot charge. A
direct comparison is made with numerically exact data, showing good agreement
for the time scales accessible by the diagrammatic Monte Carlo simulation
method.


title: Reachability in Two-Clock Timed Automata is PSPACE-complete

abstract:
  A recent result of Haase et al. has shown that reachability in two-clock
timed automata is log-space equivalent to reachability in bounded one-counter
automata. We show that reachability in bounded one-counter automata is
PSPACE-complete.


title: Concatenated Capacity-Achieving Polar Codes for Optical Quantum Channels

abstract:
  We construct concatenated capacity-achieving quantum codes for noisy optical
quantum channels. We demonstrate that the error-probability of
capacity-achieving quantum polar encoding can be reduced by the proposed
low-complexity concatenation scheme.


title:
Ring extension of entire ring with conjugation; arithmetic in entire
  rings

abstract:
  Some basic properties of the ring of integers $\mathbb{Z}$ are extended to
entire rings. In particular, arithmetic in entire principal rings is very
similar than arithmetic in the ring of integers $\mathbb{Z}$. These arithmetic
properties are derived from a $\star$-ring extension of the considered entire
ring (ring extension with conjugation) equipped with a real function which is a
multiplicative structure-preserving map between two algebras. The algebra of
this ring extension is studied in detail. Some examples of such ring extension
are given.


title:
Spectral large sieve inequalities for Hecke congruence subgroups of
  SL(2,Z[i])

abstract:
  We prove, in respect of an arbitrary Hecke congruence subgroup \Gamma
=\Gamma_0(q_0) of the group SL(2,Z[i]), some new upper bounds (or `spectral
large sieve inequalities') for sums involving Fourier coefficients of \Gamma
-automorphic cusp forms on SL(2,C). The Fourier coefficients in question may
arise from the Fourier expansion at any given cusp c of \Gamma : our results
are not limited to the case in which c is the cusp at infinity. For this
reason, our proof is reliant upon an extension, to arbitrary cusps, of the
spectral-Kloosterman sum formula for \Gamma\SL(2,C) obtained by Hristina
Lokvenec-Guleska in her doctoral thesis (generalising the sum formulae of
Roelof Bruggeman and Yoichi Motohashi for PSL(2,Z[i])\PSL(2,C) in several
respects, though not as regards the choice of cusps). A proof of the required
extension of the sum formula is given in an appendix.


title: Semiconductor Ring Lasers Coupled by a Single Waveguide

abstract:
  We experimentally and theoretically study the characteristics of
semiconductor ring lasers bidirectionally coupled by a single bus waveguide.
This configuration has, e.g., been suggested for use as an optical memory and
as an optical neural network motif. The main results are that the coupling can
destabilize the state in which both rings lase in the same direction, and it
brings to life a state with equal powers at both outputs. These are both
undesirable for optical memory operation. Although the coupling between the
rings is bidirectional, the destabilization occurs due to behavior similar to
an optically injected laser system.


title:
Polaractivation of Hidden Private Classical Capacity Region of Quantum
  Channels

abstract:
  We define a new phenomenon for communication over noisy quantum channels. The
investigated solution is called polaractivation and based on quantum polar
encoding. Polaractivation is a natural consequence of the channel polarization
effect in quantum systems and makes possible to open the hidden capacity
regions of a noisy quantum channel by using the idea of rate increment. While
in case of a classical channel only the rate of classical communication can be
increased, in case of a quantum channel the channel polarization and the rate
improvement can be exploited to open unreachable capacity regions. We
demonstrate the results for the opening of private classical capacity-domain.
We prove that the method works for arbitrary quantum channels if a given
criteria in the symmetric classical capacity is satisfied. We also derived a
necessary lower bound on the rate of classical communication for the
polaractivation of private classical capacity-domain.


title: An analytic approach to special numbers and polynomials

abstract:
  The purpose of this article is to present, in a simple way, an analytic
approach to special numbers and polynomials. The approach is based on the
derivative polynomials. The paper is, to some extent, a review article,
although it contains some new elements. In particular, it seems that some
integral representations for Bernoulli numbers and Bernoulli polynomials can be
seen as new.


title: Learning Equilibria of Games via Payoff Queries

abstract:
  A recent body of experimental literature has studied empirical
game-theoretical analysis, in which we have partial knowledge of a game,
consisting of observations of a subset of the pure-strategy profiles and their
associated payoffs to players. The aim is to find an exact or approximate Nash
equilibrium of the game, based on these observations. It is usually assumed
that the strategy profiles may be chosen in an on-line manner by the algorithm.
We study a corresponding computational learning model, and the query complexity
of learning equilibria for various classes of games. We give basic results for
bimatrix and graphical games. Our focus is on symmetric network congestion
games. For directed acyclic networks, we can learn the cost functions (and
hence compute an equilibrium) while querying just a small fraction of
pure-strategy profiles. For the special case of parallel links, we have the
stronger result that an equilibrium can be identified while only learning a
small fraction of the cost values.


title:
Correspondence Between Classical and Quantum Theory by $f$-Deformed
  Coherent State

abstract:
  Generalized $f$-coherent state approach in deformation quantization framework
is investigated by using a $\ast $-eigenvalue equation. For this purpose we
introduce a new Moyal star product called $f$-star product, so that by using
this ${\ast}_{f}$-eigenvalue equation one can obtain exactly the spectrum of a
general Hamiltonian of a deformed system.


title: The Correlation Conversion Property of Quantum Channels

abstract:
  Transmission of quantum entanglement will play a crucial role in future
networks and long-distance quantum communications. Quantum Key Distribution,
the working mechanism of quantum repeaters and the various quantum
communication protocols are all based on quantum entanglement. On the other
hand, quantum entanglement is extremely fragile and sensitive to the noise of
the communication channel over which it has been transmitted. To share
entanglement between distant points, high fidelity quantum channels are needed.
In practice, these communication links are noisy, which makes it impossible or
extremely difficult and expensive to distribute entanglement. In this work we
first show that quantum entanglement can be generated by a new idea, exploiting
the most natural effect of the communication channels: the noise itself of the
link. We prove that the noise transformation of quantum channels that are not
able to transmit quantum entanglement can be used to generate distillable
(useable) entanglement from classically correlated input. We call this new
phenomenon the Correlation Conversion property (CC-property) of quantum
channels. The proposed solution does not require any non-local operation or
local measurement by the parties, only the use of standard quantum channels.
Our results have implications and consequences for the future of quantum
communications, and for global-scale quantum communication networks. The
discovery also revealed that entanglement generation by local operations is
possible.


title: Comparision and analysis of photo image forgery detection techniques

abstract:
  Digital Photo images are everywhere, on the covers of magazines, in
newspapers, in courtrooms, and all over the Internet. We are exposed to them
throughout the day and most of the time. Ease with which images can be
manipulated; we need to be aware that seeing does not always imply believing.
We propose methodologies to identify such unbelievable photo images and
succeeded to identify forged region by given only the forged image. Formats are
additive tag for every file system and contents are relatively expressed with
extension based on most popular digital camera uses JPEG and Other image
formats like png, bmp etc. We have designed algorithm running behind with the
concept of abnormal anomalies and identify the forgery regions.


title: Fast Compressed Sensing SAR Imaging based on Approximated Observation

abstract:
  In recent years, compressed sensing (CS) has been applied in the field of
synthetic aperture radar (SAR) imaging and shows great potential. The existing
models are, however, based on application of the sensing matrix acquired by the
exact observation functions. As a result, the corresponding reconstruction
algorithms are much more time consuming than traditional matched filter (MF)
based focusing methods, especially in high resolution and wide swath systems.
In this paper, we formulate a new CS-SAR imaging model based on the use of the
approximated SAR observation deducted from the inverse of focusing procedures.
We incorporate CS and MF within an sparse regularization framework that is then
solved by a fast iterative thresholding algorithm. The proposed model forms a
new CS-SAR imaging method that can be applied to high-quality and
high-resolution imaging under sub-Nyquist rate sampling, while saving the
computational cost substantially both in time and memory. Simulations and real
SAR data applications support that the proposed method can perform SAR imaging
effectively and efficiently under Nyquist rate, especially for large scale
applications.


title:
Critical theories of phase transition between symmetry protected
  topological states and their relation to the gapless boundary theories

abstract:
  Symmetry protected topological states (SPTs) have the same symmetry and the
phase transition between them are beyond Landau's symmetry breaking formalism.
In this paper we study (1) the critical theory of phase transition between
trivial and non-trivial SPTs, and (2) the relation between such critical theory
and the gapless boundary theory of SPTs. Based on examples of SO(3) and SU(2)
SPTs, we propose that under appropriate boundary condition the critical theory
contains the delocalized version of the boundary excitations. In addition, we
prove that the boundary theory is the critical theory spatially confined
between two SPTs. We expect these conclusions to hold in general and, in
particular, for discrete symmetry groups as well.


title:
Hall conductivity as bulk signature of topological transitions in
  superconductors

abstract:
  Topological superconductors may undergo transitions between phases with
different topological numbers which, like the case of topological insulators,
are related to the presence of gapless (Majorana) edge states. In $\mathbb{Z}$
topological insulators the charge Hall conductivity is quantized, being
proportional to the number of gapless states running at the edge. In a
superconductor, however, charge is not conserved and, therefore, $\sigma_{xy}$
is not quantized, even in the case of a $\mathbb{Z}$ topological
superconductor. Here it is shown that while the $\sigma_{xy}$ evolves
continuously between different topological phases of a $\mathbb{Z}$ topological
superconductor, its derivatives display sharp features signaling the
topological transitions. We consider in detail the case of a triplet
superconductor with p-wave symmetry in the presence of Rashba spin-orbit (SO)
coupling and externally applied Zeeman spin splitting. Generalization to the
cases where the pairing vector is not aligned with that of the SO coupling is
given. We generalize also to the cases where the normal system is already
topologically non-trivial.


title:
An Analysis of Gene Expression Data using Penalized Fuzzy C-Means
  Approach

abstract:
  With the rapid advances of microarray technologies, large amounts of
high-dimensional gene expression data are being generated, which poses
significant computational challenges. A first step towards addressing this
challenge is the use of clustering techniques, which is essential in the data
mining process to reveal natural structures and identify interesting patterns
in the underlying data. A robust gene expression clustering approach to
minimize undesirable clustering is proposed. In this paper, Penalized Fuzzy
C-Means (PFCM) Clustering algorithm is described and compared with the most
representative off-line clustering techniques: K-Means Clustering, Rough
K-Means Clustering and Fuzzy C-Means clustering. These techniques are
implemented and tested for a Brain Tumor gene expression Dataset. Analysis of
the performance of the proposed approach is presented through qualitative
validation experiments. From experimental results, it can be observed that
Penalized Fuzzy C-Means algorithm shows a much higher usability than the other
projected clustering algorithms used in our comparison study. Significant and
promising clustering results are presented using Brain Tumor Gene expression
dataset. Thus patterns seen in genome-wide expression experiments can be
interpreted as indications of the status of cellular processes. In these
clustering results, we find that Penalized Fuzzy C-Means algorithm provides
useful information as an aid to diagnosis in oncology.


title:
Transverse localization in nonlinear photonic lattices with second-order
  coupling

abstract:
  We investigate numerically the effect of long-range interaction on the
transverse localization of light. To this end, nonlinear zigzag optical
waveguide lattices are applied, which allows precise tuning of the second-order
coupling. We find that localization is hindered by coupling between
next-nearest lattice sites. Additionally, (focusing) nonlinearity facilitates
localization with increasing disorder, as long as the nonlinearity is
sufficiently weak. However, for strong nonlinearities, increasing disorder
results in weaker localization. The threshold nonlinearity, above which this
anomalous result is observed grows with increasing second-order coupling.


title: Non-equilibrium steady-states in conformal field theory

abstract:
  We present a construction of non-equilibrium steady states in one-dimensional
quantum critical systems carrying energy and charge fluxes. This construction
is based on a scattering approach within a real-time hamiltonian reservoir
formulation. Using conformal field theory techniques, we prove convergence
towards steady states at large time. We discuss in which circumstances these
states describe the universal non-equilibrium regime at low temperatures. We
compute the exact large deviation functions for both energy and charge
transfers, which encode for the quantum and statistical fluctuations of these
transfers at large time. They are universal, depending only on fundamental
constants (h, k_B), on the central charge and on the external parameters such
as the temperatures or the chemical potentials, and they satisfy fluctuation
relations. A key point consists in relating the derivatives of these functions
to the linear response functions but at complex shifted external parameters.


title: Is Europe Evolving Toward an Integrated Research Area?

abstract:
  An integrated European Research Area (ERA) is a critical component for a more
competitive and open European R&D system. However, the impact of EU-specific
integration policies aimed at overcoming innovation barriers associated with
national borders is not well understood. Here we analyze 2.4 x 10^6 patent
applications filed with the European Patent Office (EPO) over the 25-year
period 1986-2010 along with a sample of 2.6 x 10^5 records from the ISI Web of
Science to quantitatively measure the role of borders in international R&D
collaboration and mobility. From these data we construct five different
networks for each year analyzed: (i) the patent co-inventor network, (ii) the
publication co-author network, (iii) the co-applicant patent network, (iv) the
patent citation network, and (v) the patent mobility network. We use methods
from network science and econometrics to perform a comparative analysis across
time and between EU and non-EU countries to determine the "treatment effect"
resulting from EU integration policies. Using non-EU countries as a control
set, we provide quantitative evidence that, despite decades of efforts to build
a European Research Area, there has been little integration above global trends
in patenting and publication. This analysis provides concrete evidence that
Europe remains a collection of national innovation systems.

categories: physics.soc-ph cs.DL cs.SI physics.data-an


title:
Weighted spectral large sieve inequalities for Hecke congruence
  subgroups of SL(2,Z[i])

abstract:
  We prove new bounds for weighted mean values of sums involving Fourier
coefficients of cusp forms that are automorphic with respect to a Hecke
congruence subgroup \Gamma =\Gamma_0(q) of the group SL(2,Z[i]), and correspond
to exceptional eigenvalues of the Laplace operator on the space
L^2(\Gamma\SL(2,C)/SU(2)). These results are, for certain applications, an
effective substitute for the generalised Selberg eigenvalue conjecture. We give
a proof of one such application, which is an upper bound for a sum of
generalised Kloosterman sums (of significance in the study of certain mean
values of Hecke zeta-functions with groessencharakters).
  Our proofs make extensive use of Lokvenec-Guleska's generalisation of the
Bruggeman-Motohashi summation formulae for PSL(2,Z[i])\PSL(2,C). We also employ
a bound of Kim and Shahidi for the first eigenvalues of the relevant Laplace
operators, and an `unweighted' spectral large sieve inequality (our proof of
which is to appear separately).


title:
LOFAR detections of low-frequency radio recombination lines towards
  Cassiopeia A

abstract:
  Cassiopeia A was observed using the Low-Band Antennas of the LOw Frequency
ARray (LOFAR) with high spectral resolution. This allowed a search for radio
recombination lines (RRLs) along the line-of-sight to this source. Five
carbon-alpha RRLs were detected in absorption between 40 and 50 MHz with a
signal-to-noise ratio of > 5 from two independent LOFAR datasets. The derived
line velocities (v_LSR ~ -50 km/s) and integrated optical depths (~ 13 s^-1) of
the RRLs in our spectra, extracted over the whole supernova remnant, are
consistent within each LOFAR dataset and with those previously reported. For
the first time, we are able to extract spectra against the brightest hotspot of
the remnant at frequencies below 330 MHz. These spectra show significantly
higher (15-80 %) integrated optical depths, indicating that there is
small-scale angular structure on the order of ~1 pc in the absorbing gas
distribution over the face of the remnant. We also place an upper limit of 3 x
10^-4 on the peak optical depths of hydrogen and helium RRLs. These results
demonstrate that LOFAR has the desired spectral stability and sensitivity to
study faint recombination lines in the decameter band.


title:
Rate analysis of inexact dual first order methods: Application to
  distributed MPC for network systems

abstract:
  In this paper we propose and analyze two dual methods based on inexact
gradient information and averaging that generate approximate primal solutions
for smooth convex optimization problems. The complicating constraints are moved
into the cost using the Lagrange multipliers. The dual problem is solved by
inexact first order methods based on approximate gradients and we prove
sublinear rate of convergence for these methods. In particular, we provide, for
the first time, estimates on the primal feasibility violation and primal and
dual suboptimality of the generated approximate primal and dual solutions.
Moreover, we solve approximately the inner problems with a parallel coordinate
descent algorithm and we show that it has linear convergence rate. In our
analysis we rely on the Lipschitz property of the dual function and inexact
dual gradients. Further, we apply these methods to distributed model predictive
control for network systems. By tightening the complicating constraints we are
also able to ensure the primal feasibility of the approximate solutions
generated by the proposed algorithms. We obtain a distributed control strategy
that has the following features: state and input constraints are satisfied,
stability of the plant is guaranteed, whilst the number of iterations for the
suboptimal solution can be precisely determined.


title:
Elimination of the linearization error and improved basis-set
  convergence within the FLAPW method

abstract:
  We analyze in detail the error that arises from the linearization in
linearized augmented-plane-wave (LAPW) basis functions around predetermined
energies $E_l$ and show that it can lead to undesirable dependences of the
calculated results on method-inherent parameters such as energy parameters
$E_l$ and muffin-tin sphere radii. To overcome these dependences, we evaluate
approaches that eliminate the linearization error systematically by adding
local orbitals (LOs) to the basis set. We consider two kinds of LOs: (i)
constructed from solutions $u_l(r,E)$ to the scalar-relativistic approximation
of the radial Dirac equation with $E>E_l$ and (ii) constructed from second
energy derivatives $\partial^2 u_l(r,E) / \partial E^2$ at $E=E_l$. We find
that the latter eliminates the error most efficiently and yields the density
functional answer to many electronic and materials properties with very high
precision. Finally, we demonstrate that the so constructed LAPW+LO basis shows
a more favorable convergence behavior than the conventional LAPW basis due to a
better decoupling of muffin-tin and interstitial regions, similarly to the
related APW+lo approach, which requires an extra set of LOs to reach the same
total energy, though.


title: Duality of liquids

abstract:
  Liquids flow, making them remarkably distinct from solids and close to gases.
At the same time, interactions in liquids are strong as in solids. The
combination of these two properties is believed to be the ultimate obstacle to
constructing a general theory of liquids. Here, we adopt a new approach to
liquids: instead of focusing on the problem of strong interactions, we zero in
on the relative contributions of vibrational and diffusional motion in liquids.
We subsequently show that from the point of view of thermodynamics, liquid
energy and specific heat are given, to a very good approximation, by their
vibrational contributions as in solids, for relaxation times spanning 15 orders
of magnitude. We therefore find that liquids show an interesting {\it duality}
not hitherto known: they are close to solids from the thermodynamical point of
view and to gases from the point of view of flow. We discuss the experimental
implications of this approach.


title: Active Galactic Nuclei: present observations and prospects

abstract:
  INTEGRAL has made a very significant contribution to our understanding of the
physics of AGN. We illustrate this progress by looking at the considerations
that were made at the time of the selection of the INTEGRAL mission and
discussing some observations and results obtained in the intervening time.
  It is seen that while a number of results pertaining to the variability of
AGN have been obtained, the potential of the INTEGRAL data in short timescale
variability domain is still largely under exploited. The characteristic
variability timescale of AGN, and X-ray binaries, can be understood in the
frame of the cascade of shocks model and more generally depends solely on the
Compton cooling properties of a hot electron plasma located at a distance
proportional to the mass of the object from a soft photon source.
  Although INTEGRAL is not a focusing instrument, it is possible to resolve a
small but significant fraction of the diffuse extragalactic background at
energies higher than 10\,keV.


title:
Double ring algorithm of solar active region eruptions within the
  framework of kinematic dynamo model

abstract:
  Recent results indicate that the Babcock-Leighton mechanism for poloidal
field creation plays an important role in the solar cycle. However, modelling
this mechanism has not always correctly captured the underlying physics. In
particular, it has been demonstrated that using a spatially distributed
near-surface alpha-effect to parametrize the Babcock-Leighton mechanism
generates results which do not agree with observations. Motivated by this, we
are developing a physically more consistent model of the solar cycle in which
we model poloidal field creation by the emergence and flux dispersal of
double-rings structures. Here we present preliminary results from this new
dynamo model.


title: The trace map of Frobenius and extending sections for threefolds

abstract:
  In this paper, by using the trace map of Frobenius, we consider problems on
extending sections for positive characteristic threefolds.


title:
Relativistic mergers of compact binaries in clusters: The fingerprint of
  the spin

abstract:
  Dense stellar systems such as globular clusters and dense nuclear clusters
are the breeding ground of sources of gravitational waves for the advanced
detectors LIGO and Virgo. These systems deserve a close study to estimate rates
and parameter distribution. This is not an easy task, since the evolution of a
dense stellar cluster involves the integration of $N$ bodies with high
resolution in time and space and including hard binaries and their encounters
and, in the case of gravitational waves (GWs), one needs to take into account
important relativistic corrections. In this work we present the first
implementation of the effect of spin in mergers in a direct-summation code,
NBODY6. We employ non-spinning post-Newtonian corrections to the Newtonian
accelerations up to 3.5 post-Newtonian (PN) order as well as the spin-orbit
coupling up to next-to-lowest order and the lowest order spin-spin coupling. We
integrate spin precession and add a consistent treatment of mergers. We analyse
the implementation by running a set of two-body experiments and then we run a
set of 500 simulations of a relativistic stellar cluster. In spite of the large
number of mergers in our tests, the application of the algorithm is robust. We
find in particular the formation of a runaway star whose spin decays with the
mass it wins, independently of the initial value of the spins of the stars.
More remarkably, the subset of compact objects that do not undergo many
mergers, and hence represent a more realistic system, has a correlation between
the final absolute spin and the initial choice for the initial distribution,
which could provide us with information about the evolution of spins in dense
clusters once the first detections have started.


title:
An Interior-Point Lagrangian Decomposition Method for Separable Convex
  Optimization

abstract:
  In this paper, we propose a distributed algorithm for solving large-scale
separable convex problems using Lagrangian dual decomposition and the
interior-point framework. By adding self-concordant barrier terms to the
ordinary Lagrangian, we prove under mild assumptions that the corresponding
family of augmented dual functions is self-concordant. This makes it possible
to efficiently use the Newton method for tracing the central path. We show that
the new algorithm is globally convergent and highly parallelizable and thus it
is suitable for solving large-scale separable convex problems.


title: Connectivity-Driven Coherence in Complex Networks

abstract:
  We study the emergence of coherence in complex networks of mutually coupled
non-identical elements. We uncover the precise dependence of the dynamical
coherence on the network connectivity, on the isolated dynamics of the elements
and the coupling function. These findings predict that in random graphs, the
enhancement of coherence is proportional to the mean degree. In locally
connected networks, coherence is no longer controlled by the mean degree, but
rather on how the mean degree scales with the network size. In these networks,
even when the coherence is absent, adding a fraction s of random connections
leads to an enhancement of coherence proportional to s. Our results provide a
way to control the emergent properties by the manipulation of the dynamics of
the elements and the network connectivity.


title: Canonical Thermal Pure Quantum State

abstract:
  A thermal equilibrium state of a quantum many-body system can be represented
by a typical pure state, which we call a thermal pure quantum (TPQ) state. We
construct the canonical TPQ state, which corresponds to the canonical ensemble
of the conventional statistical mechanics. Only a single realization of the TPQ
state gives all variables of statistical-mechanical interest. We show that TPQ
states corresponding to different ensembles give identical thermodynamic
results, and they are related by simple analytic transformations. We have thus
completed the TPQ formulation of statistical mechanics. We also show that it
has great advantages in practical applications.

categories: cond-mat.stat-mech cond-mat.str-el hep-th quant-ph


title:
Intrinsic degradation mechanism of nearly lattice-matched InAlN layers
  grown on GaN substrates

abstract:
  Thanks to its high refractive index contrast, band gap and polarization
mismatch compared to GaN, In0.17Al0.83N layers lattice-matched to GaN are an
attractive solution for applications such as distributed Bragg reflectors,
ultraviolet light-emitting diodes, or high electron mobility transistors. In
order to study the structural degradation mechanism of InAlN layers with
increasing thickness, we performed metalorganic vapor phase epitaxy of InAlN
layers of thicknesses ranging from 2 to 500 nm, on free-standing (0001) GaN
substrates with a low density of threading dislocations, for In compositions of
13.5% (layers under tensile strain), and 19.7% (layers under compressive
strain). In both cases, a surface morphology with hillocks is initially
observed, followed by the appearance of V-defects. We propose that those
hillocks arise due to kinetic roughening, and that V-defects subsequently
appear beyond a critical hillock size. It is seen that the critical thickness
for the appearance of V-defects increases together with the surface diffusion
length either by increasing the temperature or the In flux because of a
surfactant effect. In thick InAlN layers, a better (worse) In incorporation
occurring on the concave (convex) shape surfaces of the V-defects is observed
leading to a top phase-separated InAlN layer lying on the initial homogeneous
InAlN layer after V-defects coalescence. It is suggested that similar
mechanisms could be responsible for the degradation of thick InGaN layers.


title:
Fine regularity of L\'evy processes and linear (multi)fractional stable
  motion

abstract:
  In this work, we investigate the fine regularity of L\'evy processes using
the 2-microlocal formalism. This framework allows us to refine the multifractal
spectrum determined by Jaffard and, in addition, study the oscillating
singularities of L\'evy processes. The fractal structure of the latter is
proved to be more complex than the classic multifractal spectrum and is
determined in the case of alpha-stable processes. As a consequence of these
fine results and the properties of the 2-microlocal frontier, we are also able
to completely characterise the multifractal nature of the linear fractional
stable motion (extension of fractional Brownian motion to {\alpha}-stable
measures) in the case of continuous and unbounded sample paths as well. The
regularity of its multifractional extension is also presented, indirectly
providing an example of a stochastic process with a non-homogeneous and random
multifractal spectrum.


title: X-ray frequency combs from optically controlled resonance fluorescence

abstract:
  An x-ray pulse-shaping scheme is put forward for imprinting an optical
frequency comb onto the radiation emitted on a driven x-ray transition, thus
producing an x-ray frequency comb. A four-level system is used to describe the
level structure of N ions driven by narrow-bandwidth x rays, an optical
auxiliary laser, and an optical frequency comb. By including many-particle
enhancement of the emitted resonance fluorescence, a spectrum is predicted
consisting of equally spaced narrow lines which are centered on an x-ray
transition energy and separated by the same tooth spacing as the driving
optical frequency comb. Given a known x-ray reference frequency, our comb could
be employed to determine an unknown x-ray frequency. While relying on the
quality of the light fields used to drive the ensemble of ions, the model has
validity at energies from the 100 eV to the keV range.


title: Sur l'alg\'ebrisation des tissus de rang maximal

abstract:
  We show that a web of codimension at least two and of maximal rank is
isomorphic to an algebraic web. This solves a problem first consdered by Chern
and Griffiths.


title: Quantum Walks and Electric Networks

abstract:
  We prove that a quantum walk can detect the presence of a marked element in a
graph in $O(\sqrt{WR})$ steps for any initial probability distribution on
vertices. Here, $W$ is the total weight of the graph, and $R$ is the effective
resistance. This generalizes the result by Szegedy that is only applicable if
the initial distribution is stationary. We describe a time-efficient quantum
algorithm for 3-distinctness based on these ideas.


title: Queues with random back-offs

abstract:
  We consider a broad class of queueing models with random state-dependent
vacation periods, which arise in the analysis of queue-based back-off
algorithms in wireless random-access networks. In contrast to conventional
models, the vacation periods may be initiated after each service completion,
and can be randomly terminated with certain probabilities that depend on the
queue length. We examine the scaled queue length and delay in a heavy-traffic
regime, and demonstrate a sharp trichotomy, depending on how the activation
rate and vacation probability behave as function of the queue length. In
particular, the effect of the vacation periods may either (i) completely vanish
in heavy-traffic conditions, (ii) contribute an additional term to the queue
lengths and delays of similar magnitude, or even (iii) give rise to an
order-of-magnitude increase. The heavy-traffic asymptotics are obtained by
combining stochastic lower and upper bounds with exact results for some
specific cases. The heavy-traffic trichotomy provides valuable insight in the
impact of the back-off algorithms on the delay performance in wireless
random-access networks.


title: An Improved Integrality Gap for Asymmetric TSP Paths

abstract:
  The Asymmetric Traveling Salesperson Path Problem (ATSPP) is one where, given
an asymmetric metric space $(V,d)$ with specified vertices s and t, the goal is
to find an s-t path of minimum length that passes through all the vertices in
V.
  This problem is closely related to the Asymmetric TSP (ATSP), which seeks to
find a tour (instead of an $s-t$ path) visiting all the nodes: for ATSP, a
$\rho$-approximation guarantee implies an $O(\rho)$-approximation for ATSPP.
However, no such connection is known for the integrality gaps of the linear
programming relaxations for these problems: the current-best approximation
algorithm for ATSPP is $O(\log n/\log\log n)$, whereas the best bound on the
integrality gap of the natural LP relaxation (the subtour elimination LP) for
ATSPP is $O(\log n)$.
  In this paper, we close this gap, and improve the current best bound on the
integrality gap from $O(\log n)$ to $O(\log n/\log\log n)$. The resulting
algorithm uses the structure of narrow $s$-$t$ cuts in the LP solution to
construct a (random) tree spanning tree that can be cheaply augmented to
contain an Eulerian $s$-$t$ walk.
  We also build on a result of Oveis Gharan and Saberi and show a strong form
of Goddyn's conjecture about thin spanning trees implies the integrality gap of
the subtour elimination LP relaxation for ATSPP is bounded by a constant.
Finally, we give a simpler family of instances showing the integrality gap of
this LP is at least 2.


title:
Improved Dual Decomposition Based Optimization for DSL Dynamic Spectrum
  Management

abstract:
  Dynamic spectrum management (DSM) has been recognized as a key technology to
significantly improve the performance of digital subscriber line (DSL)
broadband access networks. The basic concept of DSM is to coordinate
transmission over multiple DSL lines so as to mitigate the impact of crosstalk
interference amongst them. Many algorithms have been proposed to tackle the
nonconvex optimization problems appearing in DSM, almost all of them relying on
a standard subgradient based dual decomposition approach. In practice however,
this approach is often found to lead to extremely slow convergence or even no
convergence at all, one of the reasons being the very difficult tuning of the
stepsize parameters. In this paper we propose a novel improved dual
decomposition approach inspired by recent advances in mathematical programming.
It uses a smoothing technique for the Lagrangian combined with an optimal
gradient based scheme for updating the Lagrange multipliers. The stepsize
parameters are furthermore selected optimally removing the need for a tuning
strategy. With this approach we show how the convergence of current
state-of-the-art DSM algorithms based on iterative convex approximations
(SCALE, CA-DSB) can be improved by one order of magnitude. Furthermore we apply
the improved dual decomposition approach to other DSM algorithms (OSB, ISB,
ASB, (MS)-DSB, MIW) and propose further improvements to obtain fast and robust
DSM algorithms. Finally, we demonstrate the effectiveness of the improved dual
decomposition approach for a number of realistic multi-user DSL scenarios.


title: On a stochastic Ricker competition model

abstract:
  We model the evolution of two competing populations $U_t, V_t $ by a
two-dimensional size-dependent branching process. The population
characteristics are assumed to be close to each other, as in a resident-mutant
situation. Given that $U_t = m$ and $V_t = n$ the expected values of $U_{t+1}$
and $V_{t+1}$ are given by $me^{r - K(m + bn)} $ and $ne^{\tilde r - \tilde K
(n + am)}$, respectively, where $r, \tilde r$ model the intrinsic population
growth, $K, \tilde K $ model the force of inhibition on the population growth
by the present population (such as scarcity of food), and $ a, b $ model the
interaction between the two populations. For small $K, \tilde K $ the process
typically follows the corresponding deterministic Ricker competition model
closely, for a very long time. Under some conditions, notably a mutual
invasibility condition, the deterministic model has a coexistence fixed point
in the open first quadrant. The asymptotic behaviour is studied through the
quasi-stationary distribution of the process. We initiate a study of those
distributions as the inhibitive force $K, \tilde K$ approach 0.


title:
Large critical current density improvement in Bi-2212 wires through
  groove-rolling process

abstract:
  Recently the interest about Bi-2212 round wire superconductor for high
magnetic field use has been enhancing despite the fact that an increase of the
critical current is still needed to boost its successful use in such
applications. Recent studies have demonstrated that the main obstacle to
current flow, especially in long wires, is the residual porosity inside these
Powder-In-Tube processed conductors which develops in bubbles-agglomeration
when the Bi-2212 melts. Through this work we tried to overcome this issue
acting on the wire densification by changing the deformation process. Here we
show the effects of groove-rolling versus drawing process on the critical
current density JC and on the microstructure. In particular, groove-rolled
multifilamentary wires show a JC increased by a factor of about 3 with respect
to drawn wires prepared with the same Bi-2212 powder and architecture. We think
that this approach in the deformation process is able to produce the required
improvements both because the superconducting properties are enhanced and
because it makes the fabrication process faster and cheaper.


title: Constant mean curvature, flux conservation, and symmetry

abstract:
  As first noted in Korevaar, Kusner and Solomon ("KKS"), constant mean
curvature implies a homological conservation law for hypersurfaces in ambient
spaces with Killing fields.In Theorem 3.5 here, we generalize that law by
relaxing the topological restrictions assumed in [KKS] and by allowing a
weighted mean curvature functional. We also prove a partial converse (Theorem
4.1) which roughly says that when flux is conserved along a Killing field, a
hypersurface splits into two regions: one with constant (weighted) mean
curvature, and one preserved by the Killing field. We demonstrate our theory by
using it to derive a first integral for helicoidal surfaces of constant mean
curvature in Euclidean 3-space, i.e., "twizzlers."


title:
On a Class of Two-Dimensional Douglas and Projectively Flat Finsler
  Metrics

abstract:
  In this paper, we study a class of two-dimensional Finsler metrics defined by
a Riemannian metric $\alpha$ and a 1-form $\beta$. We characterize those
metrics which are Douglasian or locally projectively flat by some equations. In
particular, it shows that the known fact that $\beta$ is always closed for
those metrics in higher dimensions is no longer true in two dimensional case.
Further, we determine the local structures of two-dimensional
$(\alpha,\beta)$-metrics which are Douglassian, and some families of examples
are given for projectively flat classes with $\beta$ being not closed.


title: Non-local combined problem

abstract:
  In this paper we consider a problem of with conditions of Bitsadze-Samarski
and the Samarski-Ionkin type for system of pseudoparabolic equations of
fourth-order with discontinuous coefficients.


title:
Pooling single-cell recordings: Scalable inference through heterogeneous
  kinetics

abstract:
  Mathematical methods together with measurements of single-cell dynamics
provide unprecedented means to reconstruct intracellular processes that are
only partly or indirectly accessible experimentally. To obtain reliable
reconstructions the pooling of measurements from several cells of a clonal
population is mandatory. The population's considerable cell-to-cell variability
originating from diverse sources poses novel computational challenges for
process reconstruction. We introduce an exact Bayesian inference framework that
properly accounts for the population heterogeneity but also retains scalability
with respect to the number of pooled cells. The key ingredient is a stochastic
process that captures the heterogeneous kinetics of a population. The method
allows to infer inaccessible molecular states, kinetic parameters, compute
Bayes factors and to dissect intrinsic, extrinsic and technical contributions
to the variability in the data. We also show how additional single-cell
readouts such as morphological features can be included into the analysis. We
then reconstruct the expression dynamics of a gene under an inducible GAL1
promoter in yeast from time-lapse microscopy data. Based on Bayesian model
selection the data yields no evidence of a refractory period for this promoter.


title:
Analytical modeling of thin film neutron converters and its application
  to thermal neutron gas detectors

abstract:
  A simple model is explored mainly analytically to calculate and understand
the PHS of single and multi-layer thermal neutron detectors and to help
optimize the design in different circumstances. Several theorems are deduced
that can help guide the design.


title:
Multicolour-metallicity Relations from Globular Clusters in NGC 4486
  (M87)

abstract:
  We present Gemini griz photometry for 521 globular cluster (GC) candidates in
a 5.5 x 5.5 arcmin field centered 3.8 arcmin to the south and 0.9 arcmin to the
west of the center of the giant elliptical galaxy NGC 4486. All these objects
have previously published (C-T1) photometry. We also present new (C-T1)
photometry for 338 globulars, within 1.7 arcmin in galactocentric radius, which
have (g-z) colors in the photometric system adopted by the Virgo Cluster Survey
of the Advanced Camera for Surveys of the Hubble Space Telescope. These
photometric data are used to define a self-consistent multicolor grid (avoiding
polynomial fits) and preliminary calibrated in terms of two chemical abundance
scales. The resulting multicolor color-chemical abundance relations are used to
test GC chemical abundance distributions. This is accomplished by modelling the
ten GC color histograms that can be defined in terms of the Cgriz bands. Our
results suggest that the best fit to the GC observed color histograms is
consistent with a genuinely bimodal chemical abundance distribution NGC(Z). On
the other side, each (blue and red) GC subpopulation follows a distinct
color-color relation.


title:
Morphological Analusis Of The Left Ventricular Eendocardial Surface
  Using A Bag-Of-Features Descriptor

abstract:
  The limitations of conventional imaging techniques have hitherto precluded a
thorough and formal investigation of the complex morphology of the left
ventricular (LV) endocardial surface and its relation to the severity of
Coronary Artery Disease (CAD). Recent developments in high-resolution
Multirow-Detector Computed Tomography (MDCT) scanner technology have enabled
the imaging of LV endocardial surface morphology in a single heart beat.
Analysis of high-resolution Computed Tomography (CT) images from a 320-MDCT
scanner allows the study of the relationship between percent Diameter Stenosis
(DS) of the major coronary arteries and localization of the cardiac segments
affected by coronary arterial stenosis. In this paper a novel approach for the
analysis using a combination of rigid transformation-invariant shape
descriptors and a more generalized isometry-invariant Bag-of-Features (BoF)
descriptor, is proposed and implemented. The proposed approach is shown to be
successful in identifying, localizing and quantifying the incidence and extent
of CAD and thus, is seen to have a potentially significant clinical impact.
Specifically, the association between the incidence and extent of CAD,
determined via the percent DS measurements of the major coronary arteries, and
the alterations in the endocardial surface morphology is formally quantified. A
multivariate regression test performed on a strict leave-one-out basis are
shown to exhibit a distinct pattern in terms of the correlation coefficient
within the cardiac segments where the incidence of coronary arterial stenosis
is localized.


title: On Square Metrics of Scalar Flag Curvature

abstract:
  We consider a special class of Finsler metrics --- square metrics which are
defined by a Riemannian metric and a 1-form on a manifold. We show that an
analogue of the Beltrami Theorem in Riemannian geometry is still true for
square metrics in dimension $n\ge 3$, namely, an $n(\ge 3)$-dimensional square
metric is locally projectively flat if and only if it is of scalar flag
curvature. Further, we determine the local structure of such metrics and
classify closed manifolds with a square metric of scalar flag curvature in
dimension $n\ge 3$.


title:
Some conjectures regarding certain Schubert structure constants in Lie
  types B and D

abstract:
  I give the details of some conjectures regarding Schubert calculus in Lie
types B and D. Specifically, I conjecture rules for Schubert structure
constants $c_{u,v}^w$ when $X_{w_0u}^v$ is a Richardson variety stable under
the spherical Levi subgroup $\C^* \times SO(n-2,\C)$ of $SO(n,\C)$.


title:
Production of Small-Scale Alfv\'en Waves by Ionospheric Depletion,
  Nonlinear Magnetosphere-Ionosphere Coupling and Phase Mixing

abstract:
  Rockets and satellites have previously observed small-scale Alfv\'en waves
inside large-scale downward field-aligned currents and numerical simulations
have associated their formation with self-consistent magnetosphere-ionosphere
coupling. The origin of these waves was previously attributed to ionospheric
feedback instability, however we show that they arise in numerical experiments
in which the instability is excluded. A new interpretation is proposed in which
strong ionospheric depletion and associated current broadening (a nonlinear
steepening/wavebreaking process) form magnetosphere-ionosphere waves inside a
downward current region and these oscillations drive upgoing inertial Alfv\'en
waves in the overlying plasma. The resulting waves are governed by
characteristic periods, which are a good match to previously observed periods
for reasonable assumed conditions. Meanwhile, wavelengths perpendicular to the
magnetic field initially map to an ionospheric scale comparable to the electron
inertial length for the low-altitude magnetosphere, but become shorter with
time due to frequency-based phase mixing of boundary waves (a new manifestation
of phase mixing). Under suitable conditions, these could act as seeds for the
ionospheric feedback instability.


title: Singular Values, Nematic Disclinations, and Emergent Biaxiality

abstract:
  Both uniaxial and biaxial nematic liquid crystals are defined by
orientational ordering of their building blocks. While uniaxial nematics only
orient the long molecular axis, biaxial order implies local order along three
axes. As the natural degree of biaxiality and the associated frame, that can be
extracted from the tensorial description of the nematic order, vanishes in the
uniaxial phase, we extend the nematic director to a full biaxial frame by
making use of a singular value decomposition of the gradient of the director
field instead. New defects and degrees of freedom are unveiled and the
similarities and differences between the uniaxial and biaxial phase are
analyzed by applying the algebraic rules of the quaternion group to the
uniaxial phase.


title:
A New Construction of Multi-receiver Authentication Codes from
  Pseudo-Symplectic Geometry over Finite Fields

abstract:
  Multi-receiver authentication codes allow one sender to construct an
authenticated message for a group of receivers such that each receiver can
verify authenticity of the received message. In this paper, we constructed one
multi-receiver authentication codes from pseudo-symplectic geometry over finite
fields. The parameters and the probabilities of deceptions of this codes are
also computed.


title:
Residual strain and piezoelectric effects in passivated GaAs/AlGaAs
  core-shell nanowires

abstract:
  We observe a systematic red shift of the band-edge of passivated
GaAs/Al0.35Ga0.65As core-shell nanowires with increasing shell thickness up to
100 nm. The shift is detected both in emission and absorption experiments,
reaching values up to 14 meV for the thickest shell nanowires. Part of this red
shift is accounted for by the small tensile strain imposed to the GaAs core by
the AlGaAs shell, in line with theoretical calculations. An additional
contribution to this red shift arises from axial piezoelectric fields which
develop inside the nanowire core due to Al fluctuations in the shell.


title: Exponential decay for sc-gradient flow lines

abstract:
  In this paper we introduce the notion of sc-action functionals and their
sc-gradient flow lines. Our approach is inspired by Floer's unregularized
gradient flow. The main result of this paper is that under a Morse condition
sc-gradient flow lines have uniform exponential decay towards critical points.
The ultimate goal for the future is to construct a M-polyfold bundle over a
M-polyfold such that the space of broken sc-gradient flow lines is the zero set
of a appropriate sc-section. Here uniform exponential decay is essential. Of
independent interest is that we derive exponential decay estimates using
interpolation inequalities as opposed to Sobolev inequalities. An advantage is
that interpolation inequalities are independent of the dimension of the source
space.


title:
Modified Klein-Gordon-Fock equations based on one-dimensional chaotic
  dynamics and groups with broken symmetry

abstract:
  Modified Klein-Gordon-Fock equations were obtained on the basis of
one-dimensional chaotic dynamics. The original Lagrangians were found. The
concepts of \textit{m}-exponential map and groups with broken symmetry are
introduced. A system of bitrial orthogonal functions is considered.


title: Monte Carlo event generators & the top quark forward--backward asymmetry

abstract:
  The leading-order accurate description of top quark pair production, as
usually employed in standard Monte Carlo event generators, gives no rise to the
generation of a forward--backward asymmetry. Yet, non-negligible --
differential as well as inclusive -- asymmetries may be produced if coherent
parton showering is used in the hadroproduction of top quark pairs. In this
contribution we summarize the outcome of our study of this effect. We present a
short comparison of different parton shower implementations and briefly comment
on the phenomenology of the colour coherence effect at the Tevatron.


title:
Berry curvature effects in the Bloch oscillations of a quantum particle
  under a strong (synthetic) magnetic field

abstract:
  We study the magnetic Bloch oscillations performed by a quantum particle
moving in a two-dimensional lattice in the presence of a strong (synthetic)
magnetic field and a uniform force. An elementary derivation of the Berry
curvature effect on the semiclassical trajectory is given as well as an
explicit connection to the classical Hall effect in the continuum limit.
Perspectives to observe these effects in optical systems using synthetic gauge
fields for photons are discussed.


title: CSI Sharing Strategies for Transmitter Cooperation in Wireless Networks

abstract:
  Multiple-antenna "based" transmitter (TX) cooperation has been established as
a promising tool towards avoiding, aligning, or shaping the interference
resulting from aggressive spectral reuse. The price paid in the form of
feedback and exchanging channel state information (CSI) between cooperating
devices in most existing methods is often underestimated however. In reality,
feedback and information overhead threatens the practicality and scalability of
TX cooperation approaches in dense networks. Hereby we addresses a "Who needs
to know what?" problem, when it comes to CSI at cooperating transmitters. A
comprehensive answer to this question remains beyond our reach and the scope of
this paper. Nevertheless, recent results in this area suggest that CSI overhead
can be contained for even large networks provided the allocation of feedback to
TXs is made non-uniform and to properly depend on the network's topology. This
paper provides a few hints toward solving the problem.


title:
Equiaffine Structure and Conjugate Ricci-symmetry of a Statistical
  Manifold

abstract:
  A condition for a statistical manifold to have an equiaffine structure is
studied. The facts that dual flatness and conjugate symmetry of a statistical
manifold are sufficient conditions for a statistical manifold to have an
equiaffine structure were obtained in [2] and [3]. In this paper, a fact that a
statistical manifold, which is conjugate Ricci-symmetric, has an equiaffine
structure is given, where conjugate Ricci-symmetry is weaker condition than
conjugate symmetry. A condition for conjugate symmetry and conjugate
Ricci-symmetry to coincide is also given.

categories: math.DS cs.IT math-ph math.DG math.IT math.MP


title:
Freeze-out Dynamics via Charged Kaon Femtoscopy in sqrt(sNN)=200 GeV
  Central Au+Au Collisions

abstract:
  We present measurements of three-dimensional correlation functions of
like-sign low transverse momentum kaon pairs from sqrt(sNN)=200 GeV Au+Au
collisions. A Cartesian surface-spherical harmonic decomposition technique was
used to extract the kaon source function. The latter was found to have a
three-dimensional Gaussian shape and can be adequately reproduced by
Therminator event generator simulations with resonance contributions taken into
account. Compared to the pion one, the kaon source function is generally
narrower and does not have the long tail along the pair transverse momentum
direction. The kaon Gaussian radii display a monotonic decrease with increasing
transverse mass m_T over the interval of 0.55<=m_T<=1.15 GeV/c^2. While the
kaon radii are adequately described by the m_T-scaling in the outward and
sideward directions, in the longitudinal direction the lowest m_T value exceeds
the expectations from a pure hydrodynamical model prediction.


title:
Volatility polarization of non-specialized investors' heterogeneous
  activity

abstract:
  Financial markets provide an ideal frame for studying decision making in
crowded environments. Both the amount and accuracy of the data allows to apply
tools and concepts coming from physics that studies collective and emergent
phenomena or self-organised and highly heterogeneous systems. We analyse the
activity of 29,930 non-expert individuals that represent a small portion of the
whole market trading volume. The very heterogeneous activity of individuals
obeys a Zipf's law, while synchronization network properties unveil a community
structure. We thus correlate individual activity with the most eminent
macroscopic signal in financial markets, that is volatility, and quantify how
individuals are clearly polarized by volatility. The assortativity by
attributes of our synchronization networks also indicates that individuals look
at the volatility rather than imitate directly each other thus providing an
interesting interpretation of herding phenomena in human activity. The results
can also improve agent-based models since they provide direct estimation of the
agent's parameters.


title: The dark side of DFT based transport calculations

abstract:
  We compare the conductance of an interacting ring of six lattice sites
threaded by flux $\pi$ in a two terminal setup with the conductance of the
corresponding Kohn-Sham particles. Based on symmetry considerations we can show
that even within (lattice) Density Functional Theory employing the exact
Functional the conductance of the Kohn-Sham particles is exactly zero, while
the conductance of the physical system is close to the unitary limit. We show
that this fundamental problem might be solved by extending the standard DFT
scheme.


title: Pre-melting of crossing vortex lattices

abstract:
  The pre-melting of high vortex density planes observed recently in layered
superconductors in tilted magnetic field is explained theoretically. Based on
the structural information of the crossing lattices of pancake and Josephson
vortices the effective vortex cage potential at different lattice sites is
determined numerically. Melting takes place when the thermal energy allows
proliferation of vacancy-interstitial pairs. It is found that the increased
density of pancake vortex stacks in the planes containing Josephson vortices,
rather than their incommensurate structure, is the main cause for pre-melting.


title:
Abundance study of the two solar-analogue CoRoT targets HD 42618 and HD
  43587 from HARPS spectroscopy

abstract:
  We present a detailed abundance study based on spectroscopic data obtained
with HARPS of two solar-analogue main targets for the asteroseismology
programme of the CoRoT satellite: HD 42618 and HD 43587. The atmospheric
parameters and chemical composition are accurately determined through a fully
differential analysis with respect to the Sun observed with the same
instrumental set-up. Several sources of systematic errors largely cancel out
with this approach, which allows us to narrow down the 1-sigma error bars to
typically 20 K in effective temperature, 0.04 dex in surface gravity, and less
than 0.05 dex in the elemental abundances. Although HD 42618 fulfils many
requirements for being classified as a solar twin, its slight deficiency in
metals and its possibly younger age indicate that, strictly speaking, it does
not belong to this class of objects. On the other hand, HD 43587 is slightly
more massive and evolved. In addition, marked differences are found in the
amount of lithium present in the photospheres of these two stars, which might
reveal different mixing properties in their interiors. These results will put
tight constraints on the forthcoming theoretical modelling of their solar-like
oscillations and contribute to increase our knowledge of the fundamental
parameters and internal structure of stars similar to our Sun.


title:
Testing convective-core overshooting using period spacings of dipole
  modes in red giants

abstract:
  Uncertainties on central mixing in main sequence (MS) and core He-burning
(He-B) phases affect key predictions of stellar evolution such as late
evolutionary phases, chemical enrichment, ages etc. We propose a test of the
extension of extra-mixing in two relevant evolutionary phases based on period
spacing Delta_P of solar-like oscillating giants. From stellar models and their
corresponding adiabatic frequencies (respectively computed with ATON and LOSC
codes) we provide the first predictions of the observable Delta_P for stars in
the red giant branch (RGB) and in the red clump (RC). We find: i) a clear
correlation between Delta_P and the mass of the helium core (M_He); the latter
in intermediate-mass stars depends on the MS overshooting, hence it can be used
to set constraints on extra mixing during MS when coupled with chemical
composition; ii) a linear dependence of the average value of the asymptotic
period spacing (<Delta_P>_a) during the He-B phase on the size of the
convective core. A first comparison with the inferred asymptotic period spacing
for Kepler RC stars suggests the need for extra mixing also during this phase,
as evinced from other observational facts.


title:
States of Low Energy in Homogeneous and Inhomogeneous, Expanding
  Spacetimes

abstract:
  We construct states on the algebra of the Klein-Gordon field that minimize
the energy density in homogeneous and in inhomogeneous spacetimes, both with
compact Cauchy hypersurfaces. The energy density is measured by geodesic
observers and smeared over a spacelike slab of spacetime, entirely containing a
Cauchy hypersurface and extended in time. We further show that these states are
Hadamard states. The present construction generalizes the construction of
States of Low Energy in Robertson-Walker spacetimes presented by Olbermann
(2007).


title:
Frenet Curves and Successor Curves: Generic Parametrizations of the
  Helix and Slant Helix

abstract:
  In classical curve theory, the geometry of a curve in three dimensions is
essentially characterized by their invariants, curvature and torsion. When they
are given, the problem of finding a corresponding curve is known as 'solving
natural equations'. Explicit solutions are known only for a handful of curve
classes, including notably the plane curves and general helices.
  This paper shows constructively how to solve the natural equations explicitly
for an infinite series of curve classes. For every Frenet curve, a family of
successor curves can be constructed which have the tangent of the original
curve as principal normal. Helices are exactly the successor curves of plane
curves and applying the successor transformation to helices leads to slant
helices, a class of curves that has received considerable attention in recent
years as a natural extension of the concept of general helices.
  The present paper gives for the first time a generic characterization of the
slant helix in three-dimensional Euclidian space in terms of its curvature and
torsion, and derives an explicit arc-length parametrization of its tangent
vector. These results expand on and put into perspective earlier work on
Salkowski curves and curves of constant precession, both of which are
subclasses of the slant helix.
  The paper also, for the benefit of novices and teachers, provides a novel and
generalized presentation of the theory of Frenet curves, which is not
restricted to curves with positive curvature. Bishop frames are examined along
with Frenet frames and Darboux frames as a useful tool in the theory of space
curves. The closed curve problem receives attention as well.


title: Unconventional Superconductivity

abstract:
  A brief review of unconventional superconductivity is given, stretching from
the halcyon days of helium-3 to the modern world of Majorana fermions. Along
the way, we will encounter such strange beasts as heavy fermion
superconductors, cuprates, and their iron-based cousins. Emphasis will be put
on the fact that in almost all cases, an accepted microscopic theory has yet to
emerge. This is attributed to the difficulty of constructing a theory of
superconductivity outside the Migdal-Eliashberg framework.


title: Large Area Single Crystal (0001) Oriented MoS2 Thin Films

abstract:
  Layered metal dichalcogenide materials are a family of semiconductors with a
wide range of energy band gaps and properties, and potential to open up new
areas of physics and technology applications. However, obtaining high crystal
quality thin films over a large area remains a challenge. Here we show that
chemical vapor deposition (CVD) can be used to achieve large area electronic
grade single crystal Molybdenum Disulfide (MoS2) thin films with the highest
mobility reported in CVD grown films so far. Growth temperature and choice of
substrate were found to critically impact the quality of film grown, and high
temperature growth on (0001) orientated sapphire yielded highly oriented single
crystal MoS2 films for the first time. Films grown under optimal conditions
were found to be of high structural quality from high-resolution X-ray
diffraction, transmission electron microscopy, and Raman measurements,
approaching the quality of reference geological MoS2. Photoluminescence and
electrical measurements confirmed the growth of optically active MoS2 with a
low background carrier concentration, and high mobility. The CVD method
reported here for the growth of high quality MoS2 thin films paves the way
towards growth of a variety of layered 2D chalcogenide semiconductors and their
heterostructures.


title:
Information Flow Analysis for a Dynamically Typed Functional Language
  with Staged Metaprogramming

abstract:
  Web applications written in JavaScript are regularly used for dealing with
sensitive or personal data. Consequently, reasoning about their security
properties has become an important problem, which is made very difficult by the
highly dynamic nature of the language, particularly its support for runtime
code generation. As a first step towards dealing with this, we propose to
investigate security analyses for languages with more principled forms of
dynamic code generation. To this end, we present a static information flow
analysis for a dynamically typed functional language with prototype-based
inheritance and staged metaprogramming. We prove its soundness, implement it
and test it on various examples designed to show its relevance to proving
security properties, such as noninterference, in JavaScript. To our knowledge,
this is the first fully static information flow analysis for a language with
staged metaprogramming, and the first formal soundness proof of a CFA-based
information flow analysis for a functional programming language.


title:
Phenomenology of $f_0(980)$ photoproduction on the proton at energies
  measured with the CLAS facility

abstract:
  In this work we present the results of a theoretical analysis of the data on
photoproduction of $f_0(980)$ meson in the laboratory photon energy between 3.0
and 3.8 GeV. A comparison is done to the measurements performed by the CLAS
collaboration at JLab accelerator for the exclusive reaction $\gamma
p\rightarrow pf_0(980)$. In the analysis the partial S-wave differential cross
section is described by a model based on Regge approach with reggeized
exchanges and distinct scenarios for the $f_0(980)\rightarrow V\gamma$ coupling
are considered. It is shown that such a process can provide information on the
resonance structure and production mechanism.


title:
HD 140283: A Star in the Solar Neighborhood that Formed Shortly After
  the Big Bang

abstract:
  HD 140283 is an extremely metal-deficient and high-velocity subgiant in the
solar neighborhood, having a location in the HR diagram where absolute
magnitude is most sensitive to stellar age. Because it is bright, nearby,
unreddened, and has a well-determined chemical composition, this star avoids
most of the issues involved in age determinations for globular clusters. Using
the Fine Guidance Sensors on the Hubble Space Telescope, we have measured a
trigonometric parallax of 17.15 +/- 0.14 mas for HD 140283, with an error
one-fifth of that determined by the Hipparcos mission. Employing modern
theoretical isochrones, which include effects of helium diffusion, revised
nuclear reaction rates, and enhanced oxygen abundance, we use the precise
distance to infer an age of 14.46 +/- 0.31 Gyr. The quoted error includes only
the uncertainty in the parallax, and is for adopted surface oxygen and iron
abundances of [O/H] = -1.67 and [Fe/H] = -2.40. Uncertainties in the stellar
parameters and chemical composition, especially the oxygen content, now
contribute more to the error budget for the age of HD 140283 than does its
distance, increasing the total uncertainty to about +/-0.8 Gyr. Within the
errors, the age of HD 140283 does not conflict with the age of the Universe,
13.77 +/- 0.06 Gyr, based on the microwave background and Hubble constant, but
it must have formed soon after the big bang.


title: Viscosity Correlators in Improved Holographic QCD

abstract:
  We study a bottom-up holographic model of large-Nc Yang-Mills theory, in
which conformal invariance is broken through the introduction of a dilaton
potential on the gravity side. We use the model to calculate the spectral
densities of the shear and bulk channels at finite temperature. In the shear
channel, we compare our results to those derived in strongly coupled N=4 Super
Yang-Mills theory as well as in weakly coupled ordinary Yang-Mills. In the bulk
channel, where the conformal result is trivial, we make comparisons with both
perturbative and lattice QCD. In both channels, we pay particular attention
into the effects of conformal invariance breaking in the IHQCD model.


title:
Finite-size effects from higher conservation laws for the
  one-dimensional Bose gas

abstract:
  We consider a generalized Lieb-Liniger model, describing a one-dimensional
Bose gas with all its conservation laws appearing in the density matrix. This
will be the case for the generalized Gibbs ensemble, or when the conserved
charges are added to the Hamiltonian. The finite-size corrections are
calculated for the energy spectrum. Large-distance asymptotics of correlation
functions are then determined using methods from conformal field theory.


title: Lattice BRST without Neuberger 0/0 problem

abstract:
  We illustrate in a simple toy model how the methods of SUSY quantum mechanics
and topological quantum field theory can be used for covariant gauge-fixing
with unbroken BRST symmetry on a finite lattice.


title: The index of symmetry of compact naturally reductive spaces

abstract:
  We introduce a geometric invariant that we call the index of symmetry, which
measures how far is a Riemannian manifold from being a symmetric space. We
compute, in a geometric way, the index of symmetry of compact naturally
reductive spaces. In this case, the so-called leaf of symmetry turns out to be
of the group type. We also study several examples where the leaf of symmetry is
not of the group type. Interesting examples arise from the unit tangent bundle
of the sphere of curvature 2, and two metrics in an Aloff-Wallach 7-manifold
and the Wallach 24-manifold.


title:
Dynamic Jahn-Teller effect and superconducting excitations in Raman
  spectra

abstract:
  We report a model study of the phonon response on the interplay of the
superconducting (SC) gap and both static and dynamic Jahn-Teller distortion and
predict the appearance of the SC and Jahn-Teller (JT) distortion gap excitation
peaks in the Raman spectra of high-Tc superconductors. The model consists of
the Hamiltonian containing static JT interaction and s-wave type SC interaction
in the conduction band. Further the phonons are coupled to the density of the
conduction electron in the band as well as to the JT split conduction band
giving rise to dynamic Jahn-Teller (DJT) interaction. The phonons are
considered in a harmonic approximation. The phonon Green's function is
calculated by Zubarev's technique and the phonon self-energy arising due to
normal electron-phonon (EP) interaction and DJT interaction. The phonon
self-energy arising due to this is calculated from the electron response
density function in the coexistence phase of the two order parameters. The
phonon spectral density predicts two excitation peaks, one due to SC gap and
the other due to JT distortion. The DJT coupling suppresses the JT gap while it
enhances SC gap as well as SC transition temperature. The evolution of these
excitation peaks are investigated by varying different model parameters of the
system.


title: Requirements for two-source entanglement concentration

abstract:
  Entanglement enhancement is a key task for quantum technologies. This
operation performed on states produced by parametric down-conversion sources
has been the object of several recent experimental investigations. In
particular, conditional preparation by photon-subtraction has been shown to
improve the entanglement of these states. Here we analyse the role played by
non-Gaussian and Gaussian measurements in more general entanglement
concentration operations performed on a pair of two-mode squeezed vacua. We
find stringent requirements for achieving an improved entanglement enhancement
by measuring jointly these two resource states.