title: Quantum mechanics, matter waves, and moving clocks

abstract:
  This paper is divided into three parts. In the first (section 1), we
demonstrate that all of quantum mechanics can be derived from the fundamental
property that the propagation of a matter wave packet is described by the same
gravitational and kinematic time dilation that applies to a clock. We will do
so in several steps, first deriving the Schroedinger equation for a
nonrelativistic particle without spin in a weak gravitational potential, and
eventually the Dirac equation in curved space-time describing the propagation
of a relativistic particle with spin in strong gravity.
  In the second part (sections 2-4), we present interesting consequences of the
above quantum mechanics: that it is possible to use wave packets as a reference
for a clock, to test general relativity, and to realize a mass standard based
on a proposed redefinition of the international system of units, wherein the
Planck constant would be assigned a fixed value. The clock achieved an absolute
accuracy of 4 parts per billion (ppb). The experiment yields the fine structure
constant $\alpha = 7.297\,352\,589(15) \times 10^{-3}$ with 2.0 ppb accuracy.
We present improvements that have reduced the leading systematic error about
8-fold and improved the statistical uncertainty to 0.33 ppb in 6 hours of
integration time, referred to $\alpha$.
  In the third part (sections 5-7), we present possible future experiments with
atom interferometry: A gravitational Aharonov-Bohm experiment and its
application as a measurement of Newton's gravitational constant, antimatter
interferometry, interferometry with charged particles, and interferometry in
space.
  We will give a review of previously published material when appropriate, but
will focus on new aspects that haven't been published before.


title:
ss3sim: An R package for fisheries stock assessment simulation with
  Stock Synthesis

abstract:
  Simulation testing is an important approach to evaluating fishery stock
assessment methods. In the last decade, the fisheries stock assessment modeling
framework Stock Synthesis (SS3) has become widely used around the world.
However, there lacks a generalized and scriptable framework for SS3 simulation
testing. Here, we introduce ss3sim, an R package that facilitates reproducible,
flexible, and rapid end-to-end simulation testing with SS3. ss3sim requires an
existing SS3 model configuration along with plain-text control files describing
alternative population dynamics, fishery properties, sampling scenarios, and
assessment approaches. ss3sim then generates an underlying 'truth' from a
specified operating model, samples from that truth, modifies and runs an
estimation model, and synthesizes the results. The simulations can be run in
parallel, reducing runtime, and the source code is free to be modified under an
open-source MIT license. ss3sim is designed to explore structural differences
between the underlying truth and assumptions of an estimation model, or between
multiple estimation model configurations. For example, ss3sim can be used to
answer questions about model misspecification, retrospective patterns, and the
relative importance of different types of fisheries data. We demonstrate the
software with an example, discuss how ss3sim complements other simulation
software, and outline specific research questions that ss3sim could address.


title: Dirac quasinormal modes for a 4-dimensional Lifshitz Black Hole

abstract:
  We study the quasinormal modes of fermionic perturbations for an
asymptotically Lifshitz black hole in 4-dimensions with dynamical exponent z=2
and plane topology for the transverse section, and we find analytically and
numerically the quasinormal modes for massless fermionic fields by using the
improved asymptotic iteration method and the Horowitz-Hubeny method. The
quasinormal frequencies are purely imaginary and negative, which guarantees the
stability of these black holes under massless fermionic field perturbations.
Remarkably, both numerical methods yield consistent results; i.e., both methods
converge to the exact quasinormal frequencies; however, the improved asymptotic
iteration method converges in a fewer number of iterations. Also, we find
analytically the quasinormal modes for massive fermionic fields for the mode
with lowest angular momentum. In this case, the quasinormal frequencies are
purely imaginary and negative, which guarantees the stability of these black
holes under fermionic field perturbations. Moreover, we show that the lowest
quasinormal frequencies have real and imaginary parts for the mode with higher
angular momentum by using the improved asymptotic iteration method.


title:
Reply to Comment on "Quantum quasicrystals of spin-orbit coupled dipolar
  bosons''

abstract:
  In a recent Letter [Phys. Rev. Lett. 111, 185304 (2013)], we proposed a
scheme for realizing quantum quasicrystals using spin-orbit coupled dipolar
bosons. We remarked that these quantum quasicrystals have additional
``phason''-like modes compared with their classical counterparts. A recent
comment by Lifshitz [arXiv:1312.1388] contests this claim. We argue here that
our enumeration of gapless modes is indeed the physically relevant one; whether
the additional modes are ``phasons'' is, however, a matter of definition.


title: Non-Fermi liquid behavior in Bose-Fermi mixtures at two dimensions

abstract:
  In this paper we study the low temperature behaviors of a system of
Bose-Fermi mixtures at two dimensions. Within a self-consistent ladder diagram
approximation, we show that at nonzero temperatures $T\rightarrow0$ the
fermions exhibit non-fermi liquid behavior. We propose that this is a general
feature of Bose-Fermi mixtures at two dimensions. An experimental signature of
this new state is proposed.


title: Discrete Morse theory for computing cellular sheaf cohomology

abstract:
  Sheaves and sheaf cohomology are powerful tools in computational topology,
greatly generalizing persistent homology. We develop an algorithm for
simplifying the computation of cellular sheaf cohomology via (discrete)
Morse-theoretic techniques. As a consequence, we derive efficient techniques
for distributed computation of (ordinary) cohomology of a cell complex.


title:
New residual-based a posteriori error estimators for lowest-order
  Raviart-Thomas element approximation to convection-diffusion-reaction
  equations

abstract:
  A new technique of residual-type a posteriori error analysis is developed for
the lowest-order Raviart-Thomas mixed finite element discretizations of
convection-diffusion-reaction equations in two- or three-dimension. Both
centered mixed scheme and upwind-weighted mixed scheme are considered. The a
posteriori error estimators, derived for the stress variable error plus scalar
displacement error in $L^{2}$-norm, can be directly computed with the solutions
of the mixed schemes without any additional cost, and are robust with respect
to the coefficients in the equations. Local efficiency dependent on local
variations in coefficients is obtained without any saturation assumption, and
holds from the cases where convection or reaction is not present to convection-
or reaction-dominated problems. The main tools of analysis are the
postprocessed approximation of scalar displacement, abstract error estimates,
and the property of modified Oswald interpolation. Numerical experiments are
reported to support our theoretical results and to show the competitive
behavior of the proposed posteriori error estimates.


title: Exact Simulation of Non-stationary Reflected Brownian Motion

abstract:
  This paper develops the first method for the exact simulation of reflected
Brownian motion (RBM) with non-stationary drift and infinitesimal variance. The
running time of generating exact samples of non-stationary RBM at any time $t$
is uniformly bounded by $\mathcal{O}(1/\bar\gamma^2)$ where $\bar\gamma$ is the
average drift of the process. The method can be used as a guide for planning
simulations of complex queueing systems with non-stationary arrival rates
and/or service time.


title: A Model for Adversarial Wiretap Channel

abstract:
  In wiretap model of secure communication the goal is to provide (asymptotic)
perfect secrecy and reliable communication over a noisy channel that is
eavesdropped by an adversary with unlimited computational power. This goal is
achieved by taking advantage of the channel noise and without requiring a
shared key. The model has attracted attention in recent years because it
captures eavesdropping attack in wireless communication. The wiretap adversary
is a passive eavesdropping adversary at the physical layer of communication. In
this paper we propose a model for adversarial wiretap (AWTP) channel that
models active adversaries at this layer. We consider a $(\rho_r, \rho_w)$
wiretap adversary who can see a fraction $\rho_r$, and modify a fraction
$\rho_w$, of the sent codeword. The code components that are read and/or
modified can be chosen adaptively, and the subsets of read and modified
components in general, can be different. AWTP codes provide secrecy and
reliability for communication over these channels. We give security and
reliability definitions and measures for these codes, and define secrecy
capacity of an AWTP channel that represents the secrecy potential of the
channel. The paper has two main contributions. First, we prove a tight upper
bound on the rate of AWTP codes with perfect secrecy for $(\rho_r,
\rho_w)$-AWTP channels, and use the bound to derive the secrecy capacity of the
channel. We prove a similar bound for $\epsilon$-secure codes also, but in this
case the bound is not tight. Second, we give an explicit construction for a
capacity achieving AWTP code family, and prove its security and efficiency
properties. We show that AWTP model is a natural generalization of Wyner's
wiretap models and somewhat surprisingly, also provides a direct generalization
for a seemingly unrelated cryptographic primitive, Secure Message Transmission
(SMT).


title:
Long-Range Spin-Triplet Helix in Proximity Induced Superconductivity in
  Spin-Orbit-Coupled Systems

abstract:
  We study proximity induced triplet superconductivity in a spin-orbit-coupled
system, and show that the \textbf{d} vector of the induced triplet
superconductivity undergoes precession that can be controlled by varying the
relative strengths of Rashba and Dresselhaus spin-orbit couplings. In
particular, a long-range spin-triplet helix is predicted when these two
spin-orbit couplings have equal strengths. We also study the Josephson junction
geometry and show that a transition between 0 and $\pi$ junctions can be
induced by controlling the spin-orbit coupling with a gate voltage. An
experimental setup is proposed to verify these effects. Conversely, the
observation of these effects can serve as a direct confirmation of triplet
superconductivity.


title:
Microwave conductivity and superfluid density in strongly overdoped
  Tl2201

abstract:
  We present measurements of the microwave surface impedance of the
single-layer cuprate Tl2201, deep in the overdoped regime, with Tc ~ 25 K.
Measurements have been made using cavity perturbation of a dielectric resonator
at 17 discrete frequencies ranging from 2.50 to 19.16 GHz, and at temperatures
from 0.12 to 27.5 K. From the surface impedance we obtain the microwave
conductivity, penetration depth and superfluid density. The superfluid density
displays a strong linear temperature dependence from 2 to 14 K, indicative of
line nodes in the energy gap. The microwave data are compared with theoretical
predictions for a d-wave superconductor with point-like impurities, with the
conclusion that disorder in Tl2201 acts predominantly in the
weak-to-intermediate-strength scattering regime, and that small-angle
scattering is important.


title:
Residual-based a posteriori error estimation for multipoint flux mixed
  finite element methods

abstract:
  A novel residual-type {\it a posteriori} error analysis technique is
developed for multipoint flux mixed finite element methods for flow in porous
media in two or three space dimensions. The derived {\it a posteriori} error
estimator for the velocity and pressure error in $L^{2}-$norm consists of
discretization and quadrature indicators, and is shown to be reliable and
efficient. The main tools of analysis are a locally postprocessed approximation
to the pressure solution of an auxiliary problem and a quadrature error
estimate. Numerical experiments are presented to illustrate the competitive
behavior of the estimator.


title:
Nonparametric Weight Initialization of Neural Networks via Integral
  Representation

abstract:
  A new initialization method for hidden parameters in a neural network is
proposed. Derived from the integral representation of the neural network, a
nonparametric probability distribution of hidden parameters is introduced. In
this proposal, hidden parameters are initialized by samples drawn from this
distribution, and output parameters are fitted by ordinary linear regression.
Numerical experiments show that backpropagation with proposed initialization
converges faster than uniformly random initialization. Also it is shown that
the proposed method achieves enough accuracy by itself without backpropagation
in some cases.


title: Upper Bound on the First Star Formation History

abstract:
  Our understanding of the nature of the extragalactic background light (EBL)
has improved with the recent development of gamma-ray observation techniques.
An open subject in the context of the EBL is the reionization epoch, which is
an important probe of the formation history of first stars, the so-called
Population III (Pop III) stars. Although the mechanisms for the formation of
Pop III stars are rather well understood on theoretical grounds, their
formation history is still veiled in mystery because of their faintness. To
shed light into this matter, we study jointly the gamma-ray opacity of distant
objects and the reionization constraints from studies of intergalactic gas. By
combining these studies, we obtain a sensitive upper bound on the Pop III star
formation rate density as $\dot\rho_{*}(z)<0.01[(1+z)/{(1+7.0)}]^{3.4}({f_{\rm
esc}}/{0.2})^{-1}({C}/{3.0})\ {\rm M}_{\odot} {\rm yr}^{-1}\ {\rm Mpc}^{-3}$ at
$z\ge7$, where $f_{\rm esc}$ and $C$ are the escape fraction of ionizing
photons from galaxies and the clumping factor of the intergalactic hydrogen
gas. This limit is a $\sim10$ times tighter constraint compared with previous
studies that take into account gamma-ray opacity constraints only. Even if we
do not include the current gamma-ray constraints, the results do not change.
This is because the detected gamma-ray sources are still at $z\le4.35$ where
the reionization has already finished.


title: Tunable Large Resonant Absorption in a Mid-IR Graphene Salisbury Screen

abstract:
  Enhancing the interaction strength between graphene and light is an important
objective for those seeking to make graphene a relevant material for future
optoelectronic applications. Plasmonic modes in graphene offer an additional
pathway of directing optical energy into the graphene sheet, while at the same
time displaying dramatically small optical confinement factors that make them
an interesting means of coupling light to atomic or molecular emitters. Here we
show that graphene plasmonic nanoresonators can be placed a quarter wavelength
from a reflecting surface and electronically tuned to mimic a surface with an
impedance closely matched to freespace (Z0 = 377{\Omega}). This geometry -
known in early radar applications as a Salisbury screen - allows for an order
of magnitude (from 2.3 to 24.5%) increase of the optical absorption in the
graphene and provides an efficient means of coupling to the highly confined
graphene plasmonic modes.


title:
On the equivalence between the modifier-adaptation and trust-region
  frameworks

abstract:
  In this short note, the recently popular modifier-adaptation framework for
real-time optimization is discussed in tandem with the well-developed
trust-region framework of numerical optimization, and it is shown that the
basic version of the former is a simplification of the latter when the problem
is unconstrained. This relation is then exploited to propose a globally
convergent modifier-adaptation algorithm using already developed trust-region
theory. Cases when the two may not be equivalent and extensions to constrained
problems are also discussed.


title: Anti-trees and right-angled Artin subgroups of braid groups

abstract:
  We prove that an arbitrary right-angled Artin group $G$ admits a
quasi-isometric group embedding into a right-angled Artin group defined by the
opposite graph of a tree. Consequently, $G$ admits quasi-isometric group
embeddings into a pure braid group and into the area-preserving diffeomorphism
groups of the 2--disk and the 2--sphere, answering questions due to
Crisp--Wiest and M. Kapovich. Another corollary is that a pure braid group
contains a closed hyperbolic manifold group as a quasi-isometrically embedded
subgroup up to dimension eight. Finally, we show that the isomorphism problem,
conjugacy problem, and membership problems are unsolvable in the class of
finitely presented subgroups of braid groups.


title: Optimal Confidence Bands for Shape-Restricted Curves

abstract:
  Let $Y$ be a stochastic process on $[0,1]$ satisfying $dY(t) = n^{1/2} f(t)
dt + dW(t)$, where $n \ge 1$ is a given scale parameter (``sample size''), $W$
is standard Brownian motion and $f$ is an unknown function. Utilizing suitable
multiscale tests we construct confidence bands for $f$ with guaranteed given
coverage probability, assuming that $f$ is isotonic or convex. These confidence
bands are computationally feasible and shown to be asymptotically sharp optimal
in an appropriate sense.


title:
Dynamical localization in a chain of hard core bosons under a periodic
  driving

abstract:
  We study the dynamics of a one-dimensional lattice model of hard core bosons
which is initially in a superfluid phase with a current being induced by
applying a twist at the boundary. Subsequently, the twist is removed and the
system is subjected to periodic $\de$-function kicks in the staggered on-site
potential. We present analytical expressions for the current and work done in
the limit of an infinite number of kicks. Using these, we show that the current
(work done) exhibit a number of dips (peaks) as a function of the driving
frequency and eventually saturates to zero (a finite value) in the limit of
large frequency. The vanishing of the current (and the saturation of the work
done) can be attributed to a dynamic localization of the hard core bosons
occurring as a consequence of the periodic driving. Remarkably, we show that
for some specific values of the driving amplitude, the localization occurs for
any value of the driving frequency. Moreover, starting from a half-filled
lattice of hard core bosons with the particles localized in the central region,
we show that the spreading of the particles occurs in a light-cone-like region
with a group velocity that vanishes when the system is dynamically localized.


title: Suppressing epidemics on networks by exploiting observer nodes

abstract:
  To control infection spreading on networks, we investigate the effect of
observer nodes that recognize infection in a neighboring node and make the rest
of the neighbor nodes immune. We numerically show that random placement of
observer nodes works better on networks with clustering than on locally
treelike networks, implying that our model is promising for realistic social
networks. The efficiency of several heuristic schemes for observer placement is
also examined for synthetic and empirical networks. In parallel with numerical
simulations of epidemic dynamics, we also show that the effect of observer
placement can be assessed by the size of the largest connected component of
networks remaining after removing observer nodes and links between their
neighboring nodes.


title:
Arbitrary Chern number generation in the three-band model from momentum
  space

abstract:
  A simple, general rule for generating a three-band model with arbitrary Chern
numbers is given. The rule is based on the idea of monopole charge-changing
unitary operations and can be realized by two types of simple unitary
operations on the original Hamiltonian. A pair of monopole charges are required
to produce desired topological numbers in the three-band model. The set of
rules presented here offers a way to produce lattice models of any desired
Chern numbers for three-sublattice situations.


title:
Quantum contextuality and joint measurement of three observables of a
  qubit

abstract:
  Whereas complementarity manifests itself via two incompatible observables,
quantum contextuality can only be revealed via the joint measurements among at
least three observables. By incorporating unsharp measurements and joint
measurements into a realistic model, we reestablish an inequality due to Liang,
Spekkens, and Wiseman rigorously based on the assumption of noncontextuality
alone. Its violation therefore unambiguously pinpoints the quantum
contextuality of a two-level system. The maximal violation is attained by three
triplewise jointly measurable observables that are pairwise jointly measured in
an incompatible way. We also present the necessary and sufficient condition of
triplewise joint measurability of three unbiased observables of a qubit.


title: Wind Energy: Forecasting Challenges for Its Operational Management

abstract:
  Renewable energy sources, especially wind energy, are to play a larger role
in providing electricity to industrial and domestic consumers. This is already
the case today for a number of European countries, closely followed by the US
and high growth countries, for example, Brazil, India and China. There exist a
number of technological, environmental and political challenges linked to
supplementing existing electricity generation capacities with wind energy.
Here, mathematicians and statisticians could make a substantial contribution at
the interface of meteorology and decision-making, in connection with the
generation of forecasts tailored to the various operational decision problems
involved. Indeed, while wind energy may be seen as an environmentally friendly
source of energy, full benefits from its usage can only be obtained if one is
able to accommodate its variability and limited predictability. Based on a
short presentation of its physical basics, the importance of considering wind
power generation as a stochastic process is motivated. After describing
representative operational decision-making problems for both market
participants and system operators, it is underlined that forecasts should be
issued in a probabilistic framework. Even though, eventually, the forecaster
may only communicate single-valued predictions. The existing approaches to wind
power forecasting are subsequently described, with focus on single-valued
predictions, predictive marginal densities and space-time trajectories.
Upcoming challenges related to generating improved and new types of forecasts,
as well as their verification and value to forecast users, are finally
discussed.


title:
The Gaia-ESO Survey: Abundance ratios in the inner-disk open clusters
  Trumpler 20, NGC 4815, NGC 6705

abstract:
  Open clusters are key tools to study the spatial distribution of abundances
in the disk and their evolution with time. Using the first release of stellar
parameters and abundances of the Gaia-ESO Survey, we analyse the chemical
properties of stars in three old/intermediate-age open clusters, namely NGC
6705, NGC 4815, and Trumpler 20, all located in the inner part of the Galactic
disk at Galactocentric radius R$_{GC}\sim$7 kpc, aiming at proving their
homogeneity and at comparing them with the field population. We study the
abundance ratios of elements belonging to two different nucleosynthetic
channels: $\alpha$-elements and iron-peak elements. The main results can be
summarised as follows: i) cluster members are chemically homogeneous within
3-$\sigma$ in all analysed elements; ii) the three clusters have comparable
[El/Fe] patters within $\sim$1-$\sigma$, but they differ in their global metal
content [El/H], with NGC 4815 having the lowest metallicity. Their [El/Fe]
ratios show differences and analogies with those of the field population, both
in the solar neighbourhood and in the bulge/inner disk; iii) comparing the
abundance ratios with the results of two chemical evolution models and with
field star abundance distributions, we find that the abundance ratios of Mg,
Ni, Ca in NGC 6705 might require an inner birthplace, implying a subsequent
variation of its R$_{GC}$ during its lifetime, consistent with previous orbit
determination. The full dataset of the Gaia-ESO Survey will be a superlative
tool to constrain the chemical evolution of our Galaxy by disentangling
different formation and evolution scenarios.


title: Mathematical models for geometric control theory

abstract:
  Just as an explicit parameterisation of system dynamics by state, i.e., a
choice of coordinates, can impede the identification of general structure, so
it is too with an explicit parameterisation of system dynamics by control.
However, such explicit and fixed parameterisation by control is commonplace in
control theory, leading to definitions, methodologies, and results that depend
in unexpected ways on control parameterisation. In this paper a framework is
presented for modelling systems in geometric control theory in a manner that
does not make any choice of parameterisation by control; the systems are called
"tautological control systems." For the framework to be coherent, it relies in
a fundamental way on topologies for spaces of vector fields. As such, classes
of systems are considered possessing a variety of degrees of regularity:
finitely differentiable; Lipschitz; smooth; real analytic. In each case,
explicit geometric seminorms are provided for the topologies of spaces of
vector fields that enable straightforward descriptions of time-varying vector
fields and control systems. As part of the development, theorems are proved for
regular (including real analytic) dependence on initial conditions of flows of
vector fields depending measurably on time. Classes of "ordinary" control
systems are characterised that interact with the regularity under consideration
in a comprehensive way. In this framework, for example, the statement that "a
smooth or real analytic control-affine system is a smooth or real analytic
control system" becomes a theorem. Correspondences between ordinary control
systems and tautological control systems are carefully examined, and trajectory
correspondence between the two classes is proved for control-affine systems and
for systems with general control dependence when the control set is compact.


title:
Scalable quantum simulation of pulsed entanglement and
  Einstein-Podolsky-Rosen steering in optomechanics

abstract:
  We demonstrate a complete, probabilistic quantum dynamical simulation of the
standard nonlinear Hamiltonian of optomechanics, including decoherence at
finite temperatures. Robust entanglement of an optical pulse with the
oscillator is predicted, as well as strong quantum steering between the optical
and mechanical systems. Importantly, our probabilistic quantum simulation
method uses the positive-P technique, which is scalable to large Hilbert
spaces.


title: Polar rings and the 3D-shape of dark matter

abstract:
  Polar ring galaxies (PRG) are unique to give insight on the 3D-shape of dark
matter haloes. Some caveats have prevented to draw clear conclusions in
previous works. Also the formation mechanisms need to be well known. All
available information on the topic is reviewed, and criteria are defined for an
ideal PRG system, in the hope of removing the ambiguities and make progress in
the domain.


title: Asymptotic freedom at zero temperature in crystalline membranes

abstract:
  We investigate effects of quantum (zero-temperature) long wavelength
fluctuations of free standing crystalline membranes, that are two-dimensional
objects embedded into three-dimensional space. The fluctuations produce
logarithmic renormalization of elasticity and bending moduli of the membranes.
We find one-loop RG-equations to demonstrate that the system is in the
"asymptotic freedom" regime that is the quantum fluctuations destabilize the
flat membrane phase.


title: Trivial Unit conjecture and Homotopy Theory

abstract:
  A homotopy theoretic description is given for trivial unit conjecture in the
group ring ZG.


title:
Magnetic states and ferromagnetic resonance in geometrically frustrated
  arrays of multilayer ferromagnetic nanoparticles ordered on triangular
  lattices

abstract:
  We present a theoretical investigation of magnetostatic interaction effects
in geometrically frustrated arrays of anisotropic multilayer ferromagnetic
nanoparticles arranged in different spatially configured systems with
triangular symmetry. We show that the interlayer magnetostatic interaction
significantly expands the opportunities to create magnetically frustrated
systems. The effects of the magnetostatic interaction in magnetization reversal
processes and the possibility to control the ferromagnetic resonance spectrum
in such systems are discussed.


title: Rogue wave solutions in AB system

abstract:
  In this paper, the generalized Darboux transformation is established to the
AB system, which mainly describes marginally unstable baroclinic wave packets
in geophysical fluids and ultra-short pulses in nonlinear optics. We find a
unified formula of Nth-order rogue wave solution for the AB system by the
direct iterative rule. In particular, rogue waves possessing several free
parameters from first to second order are calculated. The dynamics and some
interesting structures of the rogue waves are illustrated through some figures.


title: Applications of QCD Sum Rules to Heavy Quark Physics

abstract:
  In these lectures, I present several important applications of QCD sum rules
to the decay processes involving heavy-flavour hadrons. The first lecture is
introductory. As a study case, the sum rules for decay constants of the
heavy-light mesons are considered. They are relevant for the leptonic decays of
$B$-mesons. In the second lecture I describe the method of QCD light-cone sum
rules used to calculate the heavy-to-light form factors at large hadronic
recoil, such as the $B\to \pi \ell \nu_\ell$ form factors. In the third
lecture, the nonlocal hadronic amplitudes in the flavour-changing neutral
current decays $B\to K^{(*)}\ell\ell$ are discussed. Light-cone sum rules
provide important nonfactorizable contributions to these amplitudes.


title:
Wildfire Prediction to Inform Fire Management: Statistical Science
  Challenges

abstract:
  Wildfire is an important system process of the earth that occurs across a
wide range of spatial and temporal scales. A variety of methods have been used
to predict wildfire phenomena during the past century to better our
understanding of fire processes and to inform fire and land management
decision-making. Statistical methods have an important role in wildfire
prediction due to the inherent stochastic nature of fire phenomena at all
scales. Predictive models have exploited several sources of data describing
fire phenomena. Experimental data are scarce; observational data are dominated
by statistics compiled by government fire management agencies, primarily for
administrative purposes and increasingly from remote sensing observations.
Fires are rare events at many scales. The data describing fire phenomena can be
zero-heavy and nonstationary over both space and time. Users of fire modeling
methodologies are mainly fire management agencies often working under great
time constraints, thus, complex models have to be efficiently estimated. We
focus on providing an understanding of some of the information needed for fire
management decision-making and of the challenges involved in predicting fire
occurrence, growth and frequency at regional, national and global scales.


title: On the generic local Langlands correspondence for GSpin groups

abstract:
  In the case of split $GSpin$ groups, we prove an equality of $L$-functions
between automorphic local $L$-functions defined by the Langlands-Shahidi method
and local Artin $L$-functions. Our method of proof is based on previous results
of the first author which allow to reduce the problem to supercuspidal
representations of Levi subgroups of $GSpin$, by constructing Langlands
parameters for general generic irreducible admissible representations of $GSpin
$ from the one for generic irreducible supercuspidal representations of its
Levi subgroups.


title: Electrically Charged One and a Half Monopole Solution

abstract:
  Recently, we have discussed the coexistence of a finite energy one-half
monopole and a 't Hooft-Polyakov monopole of opposite magnetic charges. In this
paper, we would like to introduce electric charge into this new monopoles
configuration, thus creating a one and a half dyon. This new dyon possesses
finite energy, magnetic dipole moment and angular momentum and is able to
precess in the presence of an external magnetic field. Similar to the other
dyon solutions, when the Higgs self-coupling constant, $\lambda$, is
nonvanishing, this new dyon solution possesses critical electric charge, total
energy, magnetic dipole moment, and dipole separation as the electric charge
parameter, $\eta$, approaches one. The electric charge and total energy
increase with $\eta$ to maximum critical values as $\eta\rightarrow1$ for all
nonvanishing $\lambda$. However, the magnetic dipole moment decreases with
$\eta$ when $\lambda\geq0.1$ and the dipole separation decreases with $\eta$
when $\lambda\geq1$ to minimum critical values as $\eta\rightarrow1$.


title: A probabilistic method for gradient estimates of some geometric flows

abstract:
  In general, gradient estimates are very important and necessary for deriving
convergence results in different geometric flows, and most of them are obtained
by analytic methods. In this paper, we will apply a stochastic approach to
systematically give gradient estimates for some important geometric quantities
under the Ricci flow, the mean curvature flow, the forced mean curvature flow
and the Yamabe flow respectively. Our conclusion gives another example that
probabilistic tools can be used to simplify proofs for some problems in
geometric analysis.


title:
The Cloud's Cloudy Moment: A Systematic Survey of Public Cloud Service
  Outage

abstract:
  Inadequate service availability is the top concern when employing Cloud
computing. It has been recognized that zero downtime is impossible for
large-scale Internet services. By learning from the previous and others'
mistakes, nevertheless, it is possible for Cloud vendors to minimize the risk
of future downtime or at least keep the downtime short. To facilitate
summarizing lessons for Cloud providers, we performed a systematic survey of
public Cloud service outage events. This paper reports the result of this
survey. In addition to a set of findings, our work generated a lessons
framework by classifying the outage root causes. The framework can in turn be
used to arrange outage lessons for reference by Cloud providers. By including
potentially new root causes, this lessons framework will be smoothly expanded
in our future work.


title:
Disentangling coherent and incoherent quasielastic $J/\psi$
  photoproduction on nuclei by neutron tagging in ultraperipheral ion
  collisions at the LHC

abstract:
  We consider $J/\psi$ photoproduction in ion--ion ultraperipheral collisions
(UPCs) at the LHC and RHIC in the coherent and incoherent quasielastic channels
with and without accompanying forward neutron emission and analyze the role of
nuclear gluon shadowing at small $x$, $x=10^{-4}-10^{-2}$, in these processes.
We find that despite the good agreement between large nuclear gluon shadowing
and the ALICE data in the coherent channel, in the incoherent channel, the
leading twist approximation predicts the amount of nuclear suppression which is
by approximately a factor of $1.5$ exceeds that seen in the data. We
hypothesize that part of the discrepancy can be accounted for by the incoherent
inelastic process of $J/\psi$ photoproduction with nucleon dissociation. To
separate the high-photon-energy and low-photon-energy contributions to the $d
\sigma_{AA\to AAJ/\psi}(y)/dy$ cross section, we consider ion--ion UPCs
accompanied by neutron emission due to electromagnetic excitation of one or
both colliding nuclei. We describe the corresponding PHENIX data and make
predictions for the LHC kinematics. In addition, in the incoherent quasielastic
case, we show that the separation between the low-photon-energy and
high-photon-energy contributions can be efficiently performed by measuring the
correlation between the directions of $J/\psi$ and the emitted neutrons.


title:
Long-term operation of a double phase LAr LEM Time Projection Chamber
  with a simplified anode and extraction-grid design

abstract:
  We report on the successful operation of a double phase Liquid Argon Large
Electron Multiplier Time Projection Chamber (LAr LEM-TPC) equipped with two
dimensional projective anodes with dimensions 10$\times$10 cm$^2$, and with a
maximum drift length of 21 cm. The anodes were manufactured for the first time
from a single multilayer printed circuit board (PCB). Various layouts of the
readout views have been tested and optimised. In addition, the ionisation
charge was efficiently extracted from the liquid to the gas phase with a single
grid instead of two previously. We studied the response and the gain of the
detector to cosmic muon tracks. To study long-term stability over several
weeks, we continuously operated the chamber at fixed electric field settings.
We reproducibly observe that after an initial decrease with a characteristic
time of $\tau\approx 1.6$ days, the observed gain is stable. In 46 days of
operation, a total of 14.6 million triggers have been collected at a stable
effective gain of $G_\infty\sim 15$ corresponding to a signal-to-noise ratio
$(S/N)\gtrsim 60$ for minimum ionising tracks. During the full period, eight
discharges across the LEM were observed. A maximum effective gain of 90 was
also observed, corresponding to a signal-to-noise ratio $(S/N)\gtrsim 400$ for
minimum ionising tracks, or $S/N\approx10$ for an energy deposition of 15 keV
on a single readout channel.


title:
Early Observations on Performance of Google Compute Engine for
  Scientific Computing

abstract:
  Although Cloud computing emerged for business applications in industry,
public Cloud services have been widely accepted and encouraged for scientific
computing in academia. The recently available Google Compute Engine (GCE) is
claimed to support high-performance and computationally intensive tasks, while
little evaluation studies can be found to reveal GCE's scientific capabilities.
Considering that fundamental performance benchmarking is the strategy of
early-stage evaluation of new Cloud services, we followed the Cloud Evaluation
Experiment Methodology (CEEM) to benchmark GCE and also compare it with Amazon
EC2, to help understand the elementary capability of GCE for dealing with
scientific problems. The experimental results and analyses show both potential
advantages of, and possible threats to applying GCE to scientific computing.
For example, compared to Amazon's EC2 service, GCE may better suit applications
that require frequent disk operations, while it may not be ready yet for single
VM-based parallel computing. Following the same evaluation methodology,
different evaluators can replicate and/or supplement this fundamental
evaluation of GCE. Based on the fundamental evaluation results, suitable GCE
environments can be further established for case studies of solving real
science problems.


title: New Algorithms for $M$-Estimation of Multivariate Scatter and Location

abstract:
  We present new algorithms for $M$-estimators of multivariate scatter and
location and for symmetrized $M$-estimators of multivariate scatter. The new
algorithms are considerably faster than currently used fixed-point and related
algorithms. The main idea is to utilize a second order Taylor expansion of the
target functional and to devise a partial Newton-Raphson procedure. In
connection with symmetrized $M$-estimators we work with incomplete
$U$-statistics to accelerate our procedures initially.


title: Book inequalities

abstract:
  Information theoretical inequalities have strong ties with polymatroids and
their representability. A polymatroid is entropic if its rank function is given
by the Shannon entropy of the subsets of some discrete random variables. The
book is a special iterated adhesive extension of a polymatroid with the
property that entropic polymatroids have $n$-page book extensions over an
arbitrary spine. We prove that every polymatroid has an $n$-page book extension
over a single element and over an all-but-one-element spine. Consequently, for
polymatroids on four elements, only book extensions over a two-element spine
should be considered. F. Mat\'{u}\v{s} proved that the Zhang-Yeung inequalities
characterize polymatroids on four elements which have such a 2-page book
extension. The $n$-page book inequalities, defined in this paper, are
conjectured to characterize polymatroids on four elements which have $n$-page
book extensions over a two-element spine. We prove that the condition is
necessary; consequently every book inequality is an information inequality on
four random variables. Using computer-aided multiobjective optimization, the
sufficiency of the condition is verified up to 9-page book extensions.


title:
Limit theorems for random walks that avoid bounded sets, with
  applications to the largest gap problem

abstract:
  Consider a centred random walk in dimension one with a positive finite
variance $\sigma^2$, and let $\tau_B$ be the hitting time for a bounded Borel
set $B$ with a non-empty interior. We prove the asymptotic $P_x(\tau_B > n)
\sim \sqrt{2 / \pi} \sigma^{-1} V_B(x) n^{-1/2}$ and provide an explicit
formula for the limit $V_B$ as a function of the initial position $x$ of the
walk. We also give a functional limit theorem for the walk conditioned to avoid
$B$ by the time $n$. As a main application, consider the case that $B$ is an
interval and study the size of the largest gap $G_n$ (maximal spacing) within
the range of the walk by the time $n$. We prove a limit theorem for $G_n$,
which is shown to be of the constant order, and describe its limit
distribution. In addition, we prove an analogous result for the number of
non-visited sites within the range of an integer-valued random walk.


title:
Cardinality Maximum Flow Network Interdiction Problem Vs. The Clique
  Problem

abstract:
  Cardinality Maximum Flow Network Interdiction Problem (CMFNIP) is known to be
strongly NP-hard problem in the literature. A particular case of CMFNIP has
been shown to have reduction from clique problem. In the present work,an effort
is being made to solve this particular case of CMFNIP in polynomial time.
Direct implication of this solution is that the clique problem gets solved in
polynomial time. 3-CNF Satisfiability and Vertex Cover problems, having
reductions to and from the Clique Problem respectively, are also being solved
in polynomial time by same algorithm. The obvious conclusion of the work is P =
NP.


title: The Lasserre Hierarchy in Almost Diagonal Form

abstract:
  The Lasserre hierarchy is a systematic procedure for constructing a sequence
of increasingly tight relaxations that capture the convex formulations used in
the best available approximation algorithms for a wide variety of optimization
problems. Despite the increasing interest, there are very few techniques for
analyzing Lasserre integrality gaps. Satisfying the positive semi-definite
requirement is one of the major hurdles to constructing Lasserre gap examples.
  We present a novel characterization of the Lasserre hierarchy based on moment
matrices that differ from diagonal ones by matrices of rank one (almost
diagonal form). We provide a modular recipe to obtain positive semi-definite
feasibility conditions by iteratively diagonalizing rank one matrices.
  Using this, we prove strong lower bounds on integrality gaps of Lasserre
hierarchy for two basic capacitated covering problems. For the min-knapsack
problem, we show that the integrality gap remains arbitrarily large even at
level $n-1$ of Lasserre hierarchy. For the min-sum of tardy jobs scheduling
problem, we show that the integrality gap is unbounded at level
$\Omega(\sqrt{n})$ (even when the objective function is integrated as a
constraint). These bounds are interesting on their own, since both problems
admit FPTAS.


title: Generic criticality of community structure in random graphs

abstract:
  We examine a community structure in random graphs of size $n$ and link
probability $p/n$ determined with the Newman greedy optimization of modularity.
Calculations show that for $p<1$ communities are nearly identical with
clusters. For $p=1$ the average sizes of a community $s_{av}$ and of the giant
community $s_g$ show a power-law increase $s_{av}\sim n^{\alpha'}$ and $s_g\sim
n^{\alpha}$. From numerical results we estimate $\alpha'\approx 0.26(1)$,
$\alpha\approx 0.50(1)$, and using the probability distribution of sizes of
communities we suggest that $\alpha'=\alpha/2$ should hold. For $p>1$ the
community structure remains critical: (i) $s_{av}$ and $s_g$ have a power law
increase with $\alpha'\approx\alpha <1$; (ii) the probability distribution of
sizes of communities is very broad and nearly flat for all sizes up to $s_g$.
For large $p$ the modularity $Q$ decays as $Q\sim p^{-0.55}$, which is
intermediate between some previous estimations. To check the validity of the
results, we also determined the community structure using another method,
namely a non-greedy optimization of modularity. Tests with some benchmark
networks show that the method outperforms the greedy version. For random
graphs, however, the characteristics of the community structure determined
using both greedy an non-greedy optimizations are, within small statistical
fluctuations, the same.


title: Nonlinear elliptic equations with measures revisited

abstract:
  We study the existence of solutions of the nonlinear problem $$ \left\{
\begin{alignedat}{2} -\Delta u + g(u) & = \mu & & \quad \text{in } \Omega,\\ u
& = 0 & & \quad \text{on } \partial \Omega, \end{alignedat} \right. $$ where
$\mu$ is a Radon measure and $g : \mathbb{R} \to \mathbb{R}$ is a nondecreasing
continuous function with $g(0) = 0$. This equation need not have a solution for
every measure $\mu$, and we say that $\mu$ is a good measure if the Dirichlet
problem above admits a solution. We show that for every $\mu$ there exists a
largest good measure $\mu^* \leq \mu$. This reduced measure has a number of
remarkable properties.


title: Introduction to the Ekedahl Invariants

abstract:
  In 2009 T. Ekedahl introduced certain cohomological invariants for finite
groups. In this work we introduce these invariants and we show some of their
properties. We also give an equivalent definition for such invariants.


title: State-of-the Art Motion Estimation in the Context of 3D TV

abstract:
  Progress in image sensors and computation power has fueled studies to improve
acquisition, processing, and analysis of 3D streams along with 3D
scenes/objects reconstruction. The role of motion compensation/motion
estimation (MCME) in 3D TV from end-to-end user is investigated in this
chapter. Motion vectors (MVs) are closely related to the concept of
disparities, and they can help improving dynamic scene acquisition, content
creation, 2D to 3D conversion, compression coding, decompression/decoding,
scene rendering, error concealment, virtual/augmented reality handling,
intelligent content retrieval, and displaying. Although there are different 3D
shape extraction methods, this chapter focuses mostly on shape-from-motion
(SfM) techniques due to their relevance to 3D TV. SfM extraction can restore 3D
shape information from a single camera data.


title: Kato's inequality when $\Delta u$ is a measure

abstract:
  We extend the classical Kato's inequality in order to allow functions $u \in
L^1_\mathrm{loc}$ such that $\Delta u$ is a Radon measure. This inequality has
been applied by Brezis, Marcus, and Ponce to study the existence of solutions
of the nonlinear equation $- \Delta u + g(u) = \mu$, where $\mu$ is a measure
and $g : \mathbb{R} \to \mathbb{R}$ is an increasing continuous function.


title: Acoustic parametric pumping of spin waves

abstract:
  Recent experiments demonstrated generation of spin currents by ultrasound. We
can understand this acoustically induced spin pumping in terms of the coupling
between magnetization and lattice waves. Here we study the parametric
excitation of magnetization by longitudinal acoustic waves and calculate the
acoustic threshold power. The induced magnetization dynamics can be detected by
the spin pumping into an adjacent normal metal that displays the inverse spin
Hall effect.


title: Optimal spatial pricing strategies with transportation costs

abstract:
  We consider an optimization problem in a given region $Q$ where an agent has
to decide the price $p(x)$ of a product for every $x\in Q$. The customers know
the pricing pattern $p$ and may shop at any place $y$, paying the cost $p(y)$
and additionally a transportation cost $c(x,y)$ for a given transportation cost
function $c$. We will study two models: the first one where the agent operates
everywhere on $Q$ and a second one where the agent operates only in a
subregion. For both models we discuss the mathematical framework and we obtain
an existence result for a pricing strategy which maximizes the total profit of
the agent. We also present some particular cases where more detailed
computations can be made, as the case of concave costs, the case of quadratic
cost, and the onedimensional case. Finally we discuss possible extensions and
developments, as for instance the case of Nash equilibria when more agents
operate on the same market.


title: On-Demand WebRTC Tunneling in Restricted Networks

abstract:
  In this paper we present the implementation of a WebRTC gateway service that
can forward ad-hoc RTP data plane traffic from a browser on one local network
to a browser on another local network. The advantage compared to the existing
IETF STUN (RFC 5389), TURN (RFC 5766) and ICE (RFC 5245) protocols is that it
does not require a public host and port mapping for each participating local
host, and it works with more restrictive firewall policies. WebRTC implements
ICE which combines STUN and TURN probes to automatically find the best
connection between two peers who want to communicate. In corporate networks,
simple hole punching and NAT traversal techniques typically do not work, e.g.
because of symmetric NATs. Dynamic allocation of ports on an external 3rd party
relay service is also typically blocked on restricted hosts. In our use case,
doctors at hospitals can only access port 80 through the hospital firewall on
external machines, and they need to communicate with patients who are typically
behind a NAT in a local WiFi network. VPN solutions only work for staff but not
between patients and staff. Our solution solves this problem by redirecting all
WebRTC traffic through a gateway service on the local network that has a secure
tunnel established with a public gateway. The public gateway redirects traffic
from multiple concurrent streams securely between local gateway services that
connect to it. The local gateways also communicate with browsers on their local
network to mimic a direct browser-to-browser connection without having to
change the browser runtime. We have demonstrated that this technique works well
within the hospital network and arbitrary patient networks, without the need
for any individual host configuration. In our evaluation we show that the
latency overhead is 18-20 ms for each concurrent stream added to the same
gateway service.


title: Around the Van Daele--Schm\"udgen theorem

abstract:
  For a {bounded} non-negative self-adjoint operator acting in a complex,
infinite-dimensional, separable Hilbert space H and possessing a dense range R
we propose a new approach to characterisation of phenomenon concerning the
existence of subspaces M\subset H such that M\capR=M^\perp\capR=\{0\}. We show
how the existence of such subspaces leads to various {pathological} properties
of {unbounded} self-adjoint operators related to von Neumann theorems
\cite{Neumann}--\cite{Neumann2}. We revise the von Neumann-Van
Daele-Schm\"udgen assertions \cite{Neumann}, \cite{Daele}, \cite{schmud} to
refine them. We also develop {a new systematic approach, which allows to
construct for any {unbounded} densely defined symmetric/self-adjoint operator T
infinitely many pairs of its closed densely defined restrictions T_k\subset T
such that \dom(T^* T_{k})=\{0\} (\Rightarrow \dom T_{k}^2=\{0\}$) k=1,2 and
\dom T_1\cap\dom T_2=\{0\}, \dom T_1\dot+\dom T_2=\dom T.


title: On the family of $r$-regular graphs with Grundy number $r+1$

abstract:
  The Grundy number of a graph $G$, denoted by $\Gamma(G)$, is the largest $k$
such that there exists a partition of $V(G)$, into $k$ independent sets
$V_1,\ldots, V_k$ and every vertex of $V_i$ is adjacent to at least one vertex
in $V_j$, for every $j < i$. The objects which are studied in this article are
families of $r$-regular graphs such that $\Gamma(G) = r + 1$. Using the notion
of independent module, a characterization of this family is given for $r=3$.
Moreover, we determine classes of graphs in this family, in particular the
class of $r$-regular graphs without induced $C_4$, for $r \le 4$. Furthermore,
our propositions imply results on partial Grundy number.


title: Effects of non-linearities on magnetic field generation

abstract:
  Magnetic fields are present on all scales in the Universe. While we
understand the processes which amplify the fields fairly well, we do not have a
"natural" mechanism to generate the small initial seed fields. By using fully
relativistic cosmological perturbation theory and going beyond the usual
confines of linear theory we show analytically how magnetic fields are
generated. This is the first analytical calculation of the magnetic field at
second order, using gauge-invariant cosmological perturbation theory, and
including all the source terms. To this end, we have rederived the full set of
governing equations independently. Our results suggest that magnetic fields of
the order of $10^{-30}$ G can be generated (although this depends on the small
scale cut-off of the integral), which is largely in agreement with previous
results that relied upon numerical calculations. These fields are likely too
small to act as the primordial seed fields for dynamo mechanisms.


title:
Inclusive top pair production at Tevatron and LHC in electron/muon final
  states

abstract:
  Recent measurements of the inclusive top pair production at the Tevatron and
LHC collider in the electron/muon final states are discussed. Measurements at
the Tevatron use up to 9.7 /fb of data, and at the LHC up to 4.9 /fb of data at
$\sqrt{s}=7$ TeV and up to 20.3 /fb of data at $\sqrt{s}=8$ TeV. For the
experiments at both colliders these corresponds to the full data sets at the
given center-of-mass energies. Overall results are in agreement between the
experiments at the Tevatron and between the experiments at the LHC. All
measurements are in agreement with recent theory calculations at NNLO QCD.
Individual LHC measurements are challenging the precision of the theory
calculations.


title: Top Down Approach to Multiple Plane Detection

abstract:
  Detecting multiple planes in images is a challenging problem, but one with
many applications. Recent work such as J-Linkage and Ordered Residual Kernels
have focussed on developing a domain independent approach to detect multiple
structures. These multiple structure detection methods are then used for
estimating multiple homographies given feature matches between two images.
Features participating in the multiple homographies detected, provide us the
multiple scene planes. We show that these methods provide locally optimal
results and fail to merge detected planar patches to the true scene planes.
These methods use only residues obtained on applying homography of one plane to
another as cue for merging. In this paper, we develop additional cues such as
local consistency of planes, local normals, texture etc. to perform better
classification and merging . We formulate the classification as an MRF problem
and use TRWS message passing algorithm to solve non metric energy terms and
complex sparse graph structure. We show results on challenging dataset common
in robotics navigation scenarios where our method shows accuracy of more than
85 percent on average while being close or same as the actual number of scene
planes.


title:
Measurement, correction and implications of the intrinsic error fields
  on MAST

abstract:
  The misalignment of field coils in tokamaks can lead to toroidal asymmetries
in the magnetic field, which are known as intrinsic error fields. These error
fields often lead to the formation of locked modes in the plasma, which limit
the lowest density that is achievable. The intrinsic error fields on MAST have
been determined by the direct measurement of the toroidal asymmetry of the
fields from these coils and have been parameterised in terms of distortions to
the coils. The error fields are corrected using error field correction coils,
where the optimum correction is found by determining the current required to
ensure that the discharge is furthest from the onset of a locked mode. These
empirically derived corrections have been compared with the known coil
distortions. In the vacuum approximation there is a factor of ~ 3 difference
between the predicted and empirically determined correction. When the plasma
response is included better agreement is obtained, but there are still some
cases where the agreement is not good, which suggests that other effects such
as the non-linear coupling of the error field to the plasma are important.


title: A Mass Transportation Model for the Optimal Planning of an Urban Region

abstract:
  We propose a model to describe the optimal distributions of residents and
services in a prescribed urban area. The cost functional takes into account the
transportation costs (according to a Monge--Kantorovich-type criterion) and two
additional terms which penalize concentration of residents and dispersion of
services. The tools we use are the Monge--Kantorovich mass transportation
theory and the theory of nonconvex functionals defined on measures.


title:
Investigation of Ultrathin Layers of Bis(phthalocyaninato)lutetium(III)
  on Graphite

abstract:
  We present a comprehensive study of the adsorption of
bis(phthalocyaninato)lutetium(III) (LuPc$_2$) on highly oriented pyrolytic
graphite(0001) (HOPG). The growth and self-assembly of the molecular layers as
well as the electronic structure has been investigated systematically using
scanning tunnelling microscopy and scanning tunnelling spectroscopy combined
with density functional theory (DFT) calculations and molecular mechanics
simulations. We reveal that the adsorption of LuPc$_2$ leads to the formation
of a square-like close-packed structure on the almost inert surface of HOPG,
which is corroborated by simulations. Moreover, we observed a parallel
orientation of the LuPc$_2$ molecules in the first monolayer, whereas in
subsequent layers an increasing tilt out of the surface plane was found.
Tip-sample distance-dependent tunnelling spectroscopy measurements allowed us
to detect a shift in the energy positions of the peaks assigned to the lowest
unoccupied molecular orbital toward the Fermi energy with decreasing tip-sample
separation.


title: Estimates of bands for Laplacians on periodic equilateral metric graphs

abstract:
  We consider Laplacians on periodic equilateral metric graphs. The spectrum of
the Laplacian consists of an absolutely continuous part (which is a union of an
infinite number of non-degenerated spectral bands) plus an infinite number of
flat bands, i.e., eigenvalues of infinite multiplicity. We estimate the
Lebesgue measure of the bands on a finite interval in terms of geometric
parameters of the graph. The proof is based on spectral properties of discrete
Laplacians.


title: Particle-induced transition in foams

abstract:
  The macroscopic behaviour of foams is deeply related to rearrangements
occurring at the bubble scale, which dynamics depends on the mobility of the
interstitial phase. In this paper, we resort to drainage experiments to
quantify this mobility in particulate foams, where a particle suspension is
confined between foam bubbles. Results show a strong dependence on each
investigated parameter, i.e. bubble size, particle size and gas volume fraction
for a given particle volume fraction. A combination of these parameters has
been identified as the control parameter \lambda, which compares the particle
size to the size of passage through constrictions within the foam pore space.
\lambda\ highlights a sharp transition: for \lambda\ < 1 particles are free to
drain with the liquid, which involves the shear of the suspension in foam
interstices, for \lambda\ > 1 particles are trapped and the mobility of the
interstitial phase is strongly reduced.


title: Hamiltonian circle action with self-indexing moment map

abstract:
  Let $(M,\omega)$ be a $2n$-dimensional smooth compact symplectic manifold
equipped with a Hamiltonian circle action with only isolated fixed points and
let $\mu : M \rightarrow \R$ be a corresponding moment map. Let $\Lambda_{2k}$
be the set of all fixed points of index $2k$. In this paper, we will show that
if $\mu$ is constant on $\Lambda_{2k}$ for each $k$, then $(M,\omega)$
satisfies the hard Lefschetz property. In particular, if $(M,\omega)$ admits a
self-indexing moment map, i.e. $\mu(p) = 2k$ for every $p \in \Lambda_{2k}$ and
$k=0,1,\cdots,n,$ then $(M,\omega)$ satisfies the hard Lefschetz property.


title:
Evolution of photo-excited carrier distribution from anisotropic to
  isotropic and isotropic photon absorption in graphene

abstract:
  Femtosecond time-resolved spectroscopy using 400 nm-pump and 800 nm-probe in
CVD-grown multilayer graphene provides strong evidence for isotropic
distribution of photoexcited carrier after initial relaxation. Indicative of
such isotropic distribution is a pump polarization independence of differential
reflectivity (\DeltaR/R) and transmittance (\DeltaT/T) from pump-probe
measurements. Combined with results using 800 nm-pump in [arXiv. 1301.1743v3
(2013)], these pump polarization dependences of time-resolved spectroscopy
corroborates the evolution of photo-excited carrier distribution from
anisotropic to isotropic with carrier relaxation. And, the absorbance of
graphene is identical for in-plane and out-of-plane optical fields. No matter
the carrier distribution in momentum space, the influence of carrier on
in-plane and out-of-plane optical fields from state filling effect is
identical. The sign reversing of ps dynamics signal in graphene/graphite should
not directly relate to carrier.


title: Active Microrheology of Driven Granular Particles

abstract:
  When pulling a particle in a driven granular fluid with constant force
$F_{ex}$, the probe particle approaches a steady-state average velocity $v$.
This velocity and the corresponding friction coefficient of the probe
$\zeta=F_{ex}/v$ are obtained within a schematic model of mode-coupling theory
and compared to results from event-driven simulations. For small and moderate
drag forces, the model describes the simulation results successfully for both
the linear as well as the nonlinear region: The linear response regime
(constant friction) for small drag forces is followed by shear thinning
(decreasing friction) for moderate forces. For large forces, the model
demonstrates a subsequent increasing friction in qualitative agreement with the
data. The square-root increase of the friction with force found in [Fiege et
al., Granular Matter $\boldsymbol{14}$, 247 (2012)] is explained by a simple
kinetic theory.


title: Harmonic morphisms from homogeneous spaces of positive curvature

abstract:
  We prove local existence of complex-valued harmonic morphisms from any
Riemannian homogeneous spaces of positive curvature, except the Berger space
Sp(2)/SU(2).


title:
Unique continuation properties for relativistic Schr\"odinger operators
  with a singular potential

abstract:
  Asymptotics of solutions to relativistic fractional elliptic equations with
Hardy type potentials is established in this paper. As a consequence, unique
continuation properties are obtained.


title:
Multiconfiguration Dirac-Hartree-Fock calculations of atomic electric
  dipole moments of 225^Ra, 199^Hg, and 171^Yb

abstract:
  The multiconfiguration Dirac-Hartree-Fock (MCDHF) method has been employed to
calculate atomic electric dipole moments (EDM) of 225^Ra, 199^Hg, and 171^Yb.
For the calculations of the matrix elements we extended the relativistic atomic
structure package GRASP2K. The extension includes programs to evaluate matrix
elements of (P, T)-odd e-N tensor-pseudotensor and pseudoscalar-scalar
interactions, the atomic electric dipole interaction, the nuclear Schiff
moment, and the interaction of the electron electric dipole moment with nuclear
magnetic moments. The interelectronic interactions were accounted for through
valence and core-valence electron correlation effects. The electron shell
relaxation was included with separately optimised wave functions of opposite
parities.


title: Paracontact metric manifolds without a contact metric counterpart

abstract:
  We study non-paraSasakian paracontact metric $(\kappa,\mu)$-spaces with
$\kappa=-1$ (equivalent to $h^2=0$ but $h\neq0$). These manifolds, which do not
have a contact geometry counterpart, will be classified locally in terms of the
rank of $h$. We will also give explicit examples of every possible constant
rank of $h$.


title: Granular Structure Determined by Terahertz Scattering

abstract:
  Light-scattering in the terahertz region is demonstrated for granular matter.
A quantum-cascade laser is used in a benchtop setup to determine the
angle-dependent scattering of spherical grains as well as coffee powder and
sugar grains. For the interpretation of the form factors for the scattering
from single particles one has to go beyond the usual Rayleigh-Gans-Debye theory
and apply calculations within Mie theory. In addition to single scattering also
collective correlations can be identified and extracted as a static structure
factor.


title:
The mass-hierarchy and CP-violation discovery reach of the LBNO
  long-baseline neutrino experiment

abstract:
  The next generation neutrino observatory proposed by the LBNO collaboration
will address fundamental questions in particle and astroparticle physics. The
experiment consists of a far detector, in its first stage a 20 kt LAr double
phase TPC and a magnetised iron calorimeter, situated at 2300 km from CERN and
a near detector based on a high-pressure argon gas TPC. The long baseline
provides a unique opportunity to study neutrino flavour oscillations over their
1st and 2nd oscillation maxima exploring the $L/E$ behaviour, and
distinguishing effects arising from $\delta_{CP}$ and matter.
  In this paper we have reevaluated the physics potential of this setup for
determining the mass hierarchy (MH) and discovering CP-violation (CPV), using a
conventional neutrino beam from the CERN SPS with a power of 750 kW. We use
conservative assumptions on the knowledge of oscillation parameter priors and
systematic uncertainties. The impact of each systematic error and the precision
of oscillation prior is shown. We demonstrate that the first stage of LBNO can
determine unambiguously the MH to $>5\sigma$C.L. over the whole phase space. We
show that the statistical treatment of the experiment is of very high
importance, resulting in the conclusion that LBNO has $\sim$ 100% probability
to determine the MH in at most 4-5 years of running. Since the knowledge of MH
is indispensable to extract $\delta_{CP}$ from the data, the first LBNO phase
can convincingly give evidence for CPV on the $3\sigma$C.L. using today's
knowledge on oscillation parameters and realistic assumptions on the systematic
uncertainties.


title: Mixing properties of the one-atom maser

abstract:
  We study the relaxation properties of the quantized electromagnetic field in
a cavity under repeated interactions with single two-level atoms, so-called
one-atom maser. We improve the ergodic results obtained in [BP] and prove that,
whenever the atoms are initially distributed according to the canonical
ensemble at temparature T>0, all the invariant states are mixing. Under some
non-resonance condition this invariant state is known to be thermal equilibirum
at some renormalized temperature T* and we prove that the mixing is then
arbitrarily slow, in other words that there is no lower bound on the relaxation
speed.


title:
Variations of arthropod biodiversity due to human intervention and
  climatic variations study of a protected and a non-protected area in a
  tropical forest

abstract:
  The diversity of the arthropod fauna from the pacific coast in southern
Mexico was investigated in order to study and compare the biodiversity of two
different regions. One is located within the Biosphere reserve "La encrucijada"
and the second one on the edges of this reserve at a non-protected region. Both
regions are also ecologically different in terms of humidity and temperature.
To collect the material seven different trap methods were used, arthropods were
classified at order level, Diptera also at family level and of the Diptera
family Psychodidae, genera were also identified. Twenty-eight orders have been
identified, showing some regional differences in composition and abundance. As
a general conclusion we observe that no big statistical differences can be
observed at order or family level (only Diptera) between the protected area and
the non-protected area. This difference shows an unexpected greater diversity
in the non-protected area. At genus level (only Psychodidae) however, the
diversity of moth flies was slightly greater in the preserved area. We conclude
that climatic variations are probably playing an important role at low
systematic level (order and family) and that human intervention (e.g.
agriculture) becomes more important at genus level.


title: A magic pyramid of supergravities

abstract:
  By formulating N = 1, 2, 4, 8, D = 3, Yang-Mills with a single Lagrangian and
single set of transformation rules, but with fields valued respectively in
R,C,H,O, it was recently shown that tensoring left and right multiplets yields
a Freudenthal-Rosenfeld-Tits magic square of D = 3 supergravities. This was
subsequently tied in with the more familiar R,C,H,O description of spacetime to
give a unified division-algebraic description of extended super Yang-Mills in D
= 3, 4, 6, 10. Here, these constructions are brought together resulting in a
magic pyramid of supergravities. The base of the pyramid in D = 3 is the known
4x4 magic square, while the higher levels are comprised of a 3x3 square in D =
4, a 2x2 square in D = 6 and Type II supergravity at the apex in D = 10. The
corresponding U-duality groups are given by a new algebraic structure, the
magic pyramid formula, which may be regarded as being defined over three
division algebras, one for spacetime and each of the left/right Yang-Mills
multiplets. We also construct a conformal magic pyramid by tensoring conformal
supermultiplets in D = 3, 4, 6. The missing entry in D = 10 is suggestive of an
exotic theory with G/H duality structure F4(4)/Sp(3) x Sp(1).


title: Bernoulli trials of fixed parity, random and randomly oriented graphs

abstract:
  Suppose you can color $n$ \emph{biased} coins with $n$ colors, all coins
having the same bias. It is forbidden to color both sides of a coin with the
same color, but all other colors are allowed. Let $X$ be the number of
different colors after a toss of the coins. We present a method to obtain an
upper bound on a median of $X$. Our method is based on the analysis of the
probability distribution of the number of vertices with even in-degree in
graphs whose edges are given random orientations. Our analysis applies to the
distribution of the number of vertices with odd degree in random sub-graphs of
fixed graphs. It turns out that there are parity restrictions on the random
variables that are under consideration. Hence, in order to present our result,
we introduce a class of Bernoulli random variables whose total number of
successes is of fixed parity and are closely related to Poisson trials
conditional on the event that their outcomes have fixed parity.


title:
Reduction the secular solution to the periodic solution in the
  generalized restricted three-body problem

abstract:
  The aim of the present work is to reduce the secular solution around the
triangular equilibrium points to periodic solution in the frame work of the
generalized restricted thee-body problem. This model is generalized in sense
that both the primaries are oblate and radiating as well as the gravitational
potential from a belt. We show that the linearized equation of motion of the
infinitesimal body around the triangular equilibrium points has a secular
solution when the value of mass ratio equals the critical mass value. Moreover,
we reduce this solution to periodic solution, as well as some numerical and
graphical investigations for the effects of the perturbed forces are
introduced. This model can be used to examine the existence of a dust particle
near the triangular points of an oblate and radiating binary stars system
surrounded by a belt.

categories: astro-ph.SR astro-ph.EP math-ph math.DS math.MP


title: Left-symmetric algebroids

abstract:
  In this paper, we introduce a notion of a left-symmetric algebroid, which is
a generalization of a left-symmetric algebra from a vector space to a vector
bundle. The left multiplication gives rise to a representation of the
corresponding sub-adjacent Lie algebroid. We construct left-symmetric
algebroids from $\mathcal O$-operators on Lie algebroids. We study phase spaces
of Lie algebroids in terms of left-symmetric algebroids. Representations of
left-symmetric algebroids are studied in detail. At last, we study deformations
of left-symmetric algebroids, which could be controlled by the second
cohomology class in the deformation cohomology.


title:
On the convergence of solutions for SPDEs under perturbation of the
  domian

abstract:
  We concern the effect of domain perturbation on the behaviour of stochastic
partial differential equations subject to the Dirichlet boundary condition.
Under some assumptions, we get an estimate for the solutions under changes of
the domain.


title: Quark and gluon spin-2 form factors to two-loops in QCD

abstract:
  We present complete two-loop radiative corrections to the
graviton-quark-antiquark form factor G^* \rightarrow q \overline q and
graviton-gluon-gluon form factor G^* \rightarrow g g in SU(N) gauge theory with
n_f light flavours using d-dimensional regularisation to all orders in
\varepsilon=d-4. This is an important ingredient to next-to-next-to-leading
order QCD corrections to hadronic scattering processes in models with large
extra-dimensions where Kaluza-Klein graviton modes couple to Standard Model
fields. We show that these form factors obey Sudakov integro-differential
equation and the resulting cusp, collinear and soft anomalous dimensions
coincide with those of electroweak vector boson and gluon form factors. We also
find the universal behaviour of the infrared singularities in accordance with
the proposal by Catani.


title:
Study of superfluid $^3$He under nanoscale confinement. A new approach
  to the investigation of superfluid $^3$He films

abstract:
  We review recent experiments in which superfluid $^3$He has been studied
under highly controlled confinement in nanofluidic sample chambers. We discuss
the experimental challenges and their resolution. These methods open the way to
a systematic investigation of the superfluidity of $^3$He films, and the
surface and edge excitations of topological superfluids.


title: On the Forelli-Rudin projection theorem

abstract:
  Motivated by the Forelli--Rudin projection theorem we give in this paper a
criterion for boundedness of an integral operator on weighted Lebesgue spaces
in the interval $(0,1)$. We also calculate the precise norm of this integral
operator. This is the content of the first part of the paper. In the second
part, as applications, we give some results concerning the Bergman projection
and the Berezin transform. We derive a generalization of the Dostani\'{c}
result on the norm of the Berezin transform acting on Lebesgue spaces over the
unit ball in $\mathbf{C}^n$.


title:
Few-cycle optical solitary waves in cascaded-quadratic-cubic-quintic
  nonlinear media

abstract:
  We study the propagation of few-cycle optical solitary waves in a nonlinear
media under the combined action of quadratic, cubic and quintic nonlinearities
in a large phase-mismatched second harmonic (SHG) process. Exact bright and
dark soliton solutions to the nonlinear evolution equation for cascaded
quadratic media beyond the slowly varying envelope approximations is reported.
The analytical solutions obtained are verified through numerical simulations.


title: Guiding a General-Purpose C Verifier to Prove Cryptographic Protocols

abstract:
  We describe how to verify security properties of C code for cryptographic
protocols by using a general-purpose verifier. We prove security theorems in
the symbolic model of cryptography. Our techniques include: use of ghost state
to attach formal algebraic terms to concrete byte arrays and to detect
collisions when two distinct terms map to the same byte array; decoration of a
crypto API with contracts based on symbolic terms; and expression of the
attacker model in terms of C programs. We rely on the general-purpose verifier
VCC; we guide VCC to prove security simply by writing suitable header files and
annotations in implementation files, rather than by changing VCC itself. We
formalize the symbolic model in Coq in order to justify the addition of axioms
to VCC.


title:
A General, Fast, and Robust Implementation of the Time-Optimal Path
  Parameterization Algorithm

abstract:
  Finding the Time-Optimal Parameterization of a given Path (TOPP) subject to
kinodynamic constraints is an essential component in many robotic theories and
applications. The objective of this article is to provide a general, fast and
robust implementation of this component. For this, we give a complete solution
to the issue of dynamic singularities, which are the main cause of failure in
existing implementations. We then present an open-source implementation of the
algorithm in C++/Python and demonstrate its robustness and speed in various
robotics settings.


title:
Nonlocal and global dynamics of cellular automata: A theoretical
  computer arithmetic for real continuous maps

abstract:
  A digit function is presented which provides the $i$th-digit in base $p$ of
any real number $x$. By means of this function, formulated within
$\mathcal{B}$-calculus, the local, nonlocal and global dynamical behaviors of
cellular automata (CAs) are systematically explored and universal maps are
derived for the three levels of description. None of the maps contain any
freely adjustable parameter and they are valid for any number of symbols in the
alphabet $p$ and neighborhood range $\rho$. A discrete general method to
approximate any real continuous map in the unit interval by a CA on the
rational numbers $\mathbb{Q}$ (Diophantine approximation) is presented. This
result leads to establish a correspondence between the qualitative behavior
found in bifurcation diagrams of real nonlinear maps and the Wolfram classes of
CAs. The method is applied to the logistic map, for which a logistic CA is
derived. The period doubling cascade into chaos is interpreted as a sequence of
global cellular automata of Wolfram's class 2 leading to Class 3 aperiodic
behavior. Class 4 behavior is also found close to the period-3 orbits.

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


title: Borromean ground state of fermions in two dimensions

abstract:
  The study of quantum mechanical bound states is as old as quantum theory
itself. Yet, it took many years to realize that three-body borromean systems
that are bound when any two-body subsystem is unbound are abundant in nature.
Here we demonstrate the existence of borromean systems of spin-polarized
(spinless) identical fermions in two spatial dimensions. The ground state with
zero orbital (planar) angular momentum exists in a borromean window between
critical two- and three-body strengths. The doubly degenerate first excited
states of angular momentum one appears only very close to the two-body
threshold. They are the lowest in a possible sequence of so-called super-Efimov
states. While the observation of the super-Efimov scaling could be very
difficult, the borromean ground state should be observable in cold atomic gases
and could be the basis for producing a quantum gas of three-body states in two
dimensions.

categories: cond-mat.quant-gas math-ph math.MP nucl-th quant-ph


title:
Spatial and Spatio-Temporal Log-Gaussian Cox Processes: Extending the
  Geostatistical Paradigm

abstract:
  In this paper we first describe the class of log-Gaussian Cox processes
(LGCPs) as models for spatial and spatio-temporal point process data. We
discuss inference, with a particular focus on the computational challenges of
likelihood-based inference. We then demonstrate the usefulness of the LGCP by
describing four applications: estimating the intensity surface of a spatial
point process; investigating spatial segregation in a multi-type process;
constructing spatially continuous maps of disease risk from spatially discrete
data; and real-time health surveillance. We argue that problems of this kind
fit naturally into the realm of geostatistics, which traditionally is defined
as the study of spatially continuous processes using spatially discrete
observations at a finite number of locations. We suggest that a more useful
definition of geostatistics is by the class of scientific problems that it
addresses, rather than by particular models or data formats.


title: Basic and bibasic identities related to divisor functions

abstract:
  Using basic hypergeometric functions and partial fraction decomposition we
give a new kind of generalization of identities due to Uchimura, Dilcher, Van
Hamme, Prodinger, and Chen-Fu related to divisor functions. An identity
relating Lambert series to Eulerian polynomials is also proved.


title:
Spectral theory of the G-symmetric tridiagonal matrices related to
  Stahl's counterexample

abstract:
  We recast Stahl's counterexample from the point of view of the spectral
theory of the underlying non-symmetric Jacobi matrices. In particular, it is
shown that these matrices are self-adjoint and non-negative in a Krein space
and have empty resolvent sets. In fact, the technique of Darboux
transformations (aka commutation methods) on spectra which is used in the
present paper allows us to treat the class of all G-non-negative tridiagonal
matrices. We also establish a correspondence between this class of matrices and
the class of signed measures with one sign change. Finally, it is proved that
the absence of the spurious pole at infinity for Pad\'e approximants is
equivalent to the definitizability of the corresponding tridiagonal matrix.


title: Colossal Spin Hall Effect in Ultrathin Metallic Films

abstract:
  We predict spin Hall angles up to 80% for ultrathin noble metal films with
substitutional Bi impurities. The colossal spin Hall effect is caused by
enhancement of the spin Hall conductivity in reduced sample dimension and a
strong reduction of the charge conductivity by resonant impurity scattering.
These findings can be exploited to create materials with high efficiency of
charge to spin current conversion by strain engineering.


title: Supersymmetric rotating black hole spacetime tested by geodesics

abstract:
  We present the complete analytical solution of the geodesics equations in the
supersymmetric BMPV spacetime \cite{Breckenridge:1996is}. We study
systematically the properties of massive and massless test particle motion. We
analyze the trajectories with analytical methods based on the theory of
elliptic functions. Since the nature of the effective potential depends
strongly on the rotation parameter $\omega$, one has to distinguish between the
underrotating case, the critical case and the overrotating case, as discussed
by Gibbons and Herdeiro in their pioneering study \cite{Gibbons:1999uv}. We
discuss various properties which distinguish this spacetime from the classical
relativistic spacetimes like Schwarzschild, Reissner-Nordstr\"om, Kerr or
Myers-Perry. The overrotating BMPV spacetime allows, for instance, for
planetary bound orbits for massive and massless particles. We also address
causality violation as analyzed in \cite{Gibbons:1999uv}.


title: Some congruences related to the q-Fermat quotients

abstract:
  We give q-analogues of the following congruences by Z.-W. Sun:
\sum_{k=1}^{p-1}\frac{D_k}{k} \equiv -\frac{2^{p-1}-1}{p} \pmod p,\\
\sum_{k=1}^{p-1}\frac{H_k}{k 2^k}\equiv 0 \pmod{p},\quad p\geqslant 5, where p
is a prime, D_n=\sum_{k=0}^{n}{n+k\choose 2k}{2k\choose k} are the Delannoy
numbers, and H_n=\sum_{k=1}^n\frac{1}{k} are the harmonic numbers. We also
prove that, for any positive integer m and prime p>m+1, \sum_{1\leqslant
k_1\leqslant \cdots \leqslant k_m\leqslant p-1}\frac{1}{k_1\cdots k_m 2^{k_m}}
\equiv\frac{1}{2}\sum_{k=1}^{p-1}\frac{(-1)^{k-1}}{k^m} \pmod p, which is a
multiple generalization of Kohnen's congruence. Furthermore, a q-analogue of
this congruence is established.


title:
One-site density matrix renormalization group and alternating minimum
  energy algorithm

abstract:
  Given in the title are two algorithms to compute the extreme eigenstate of a
high-dimensional Hermitian matrix using the tensor train (TT) / matrix product
states (MPS) representation. Both methods empower the traditional alternating
direction scheme with the auxiliary (e.g. gradient) information, which
substantially improves the convergence in many difficult cases. Being
conceptually close, these methods have different derivation, implementation,
theoretical and practical properties. We emphasize the differences, and
reproduce the numerical example to compare the performance of two algorithms.


title: Translating Concepts of State Transfer to Spin-1 Chains

abstract:
  State transfer is a well-known routine for various systems of
spins-$\frac{1}2$. Still, it is not well studied for chains of spins of larger
magnitudes. In this contribution we argue that while perfect state transfer may
seem unnatural in spin-1 systems, it is still feasible for arrays of V-type
three-level atoms. Tomography of such 1D array is also shown to be possible by
acting on one atom from such an array.


title:
Electrical control of spin relaxation time in complex quantum
  nanostructures

abstract:
  Spin related phenomena in quantum nanostructures have attracted recently much
interest due to fast growing field of spintronics. In particular complex
nanostructures are important as they provide a versatile system to manipulate
spin and the electronic states. Such systems can be used as spin memory devices
or scalable quantum bits. We investigate the spin relaxation for an electron in
a complex structure composed of a quantum dot surrounded by a quantum ring. We
shown that modifications of the confinement potential result in the substantial
increase of the spin relaxation time.


title:
The Josephson current in Fe-based superconducting junctions: theory and
  experiment

abstract:
  We present theory of dc Josephson effect in contacts between Fe-based and
spin-singlet $s$-wave superconductors. The method is based on the calculation
of temperature Green's function in the junction within the tight-binding model.
We calculate the phase dependencies of the Josephson current for different
orientations of the junction relative to the crystallographic axes of Fe-based
superconductor. Further, we consider the dependence of the Josephson current on
the thickness of an insulating layer and on temperature. Experimental data for
PbIn/Ba$_{1-x}$K$_{x}$(FeAs)$_2$ point-contact Josephson junctions are
consistent with theoretical predictions for $s_{\pm}$ symmetry of an order
parameter in this material. The proposed method can be further applied to
calculations of the dc Josephson current in contacts with other new
unconventional multiorbital superconductors, such as $Sr_2RuO_4$ and
superconducting topological insulator $Cu_xBi_2Se_3$.


title: Fair assignment of indivisible objects under ordinal preferences

abstract:
  We consider the discrete assignment problem in which agents express ordinal
preferences over objects and these objects are allocated to the agents in a
fair manner. We use the stochastic dominance relation between fractional or
randomized allocations to systematically define varying notions of
proportionality and envy-freeness for discrete assignments. The computational
complexity of checking whether a fair assignment exists is studied for these
fairness notions. We also characterize the conditions under which a fair
assignment is guaranteed to exist. For a number of fairness concepts,
polynomial-time algorithms are presented to check whether a fair assignment
exists. Our algorithmic results also extend to the case of unequal entitlements
of agents. Our NP-hardness result, which holds for several variants of
envy-freeness, answers an open question posed by Bouveret, Endriss, and Lang
(ECAI 2010). We also propose fairness concepts that always suggest a non-empty
set of assignments with meaningful fairness properties. Among these concepts,
optimal proportionality and optimal weak proportionality appear to be desirable
fairness concepts.


title:
Polynomial-Time Amoeba Neighborhood Membership and Faster Localized
  Solving

abstract:
  We derive efficient algorithms for coarse approximation of algebraic
hypersurfaces, useful for estimating the distance between an input polynomial
zero set and a given query point. Our methods work best on sparse polynomials
of high degree (in any number of variables) but are nevertheless completely
general. The underlying ideas, which we take the time to describe in an
elementary way, come from tropical geometry. We thus reduce a hard algebraic
problem to high-precision linear optimization, proving new upper and lower
complexity estimates along the way.


title:
Josephson Effect and Triplet--Singlet Ratio of Non--centrosymmetric
  Superconductors

abstract:
  We calculate the Andreev bound states and the corresponding Josephson current
for an asymmetric 2-dimensional Josephson junction by solving
Bogoliubov-de-Gennes equations. The junction consists of a non-centrosymmetric
superconductor (NCS) separated by a tunneling barrier with a variable height to
a conventional s-wave superconductor. In addition to the antisymmetric
spin-orbit coupling in the NCS on the one side, this asymmetric junction gives
rise to a Rashba spin-orbit coupling at the interface. We explore the rich
parameter space and recover various limiting cases such as s-wave/p-wave
junction and the asymmetric s-wave junctions. In addition, we report a
transition from a 0-junction to a pi/2-junction with increasing triplet-singlet
pairing ratio of the NCS, which serves as a novel mechanism to determine the
unknown ratio in a variety of NCS's.


title:
Some considerations about Java implementation of two provably secure
  pseudorandom bit generators

abstract:
  The quest for a cryptographically secure pseudorandom bit generator (PRBG)
was initiated long ago, and for a long time the proposed pseudorandom
generators were very slow. More recently some "provably secure" PRBG capable to
achieve a throughput rate greater than 1Mbit/sec. We noticed, anyway, the
absence of Java implementations of such PRBGs, provably due to poor expected
values for throughput rate. In the present paper we show that it is quite easy
to write down Java implementations for them, achieving a throughput rae into
range $0,5\div 7$ Mbit/sec on very common mobile low-end devices.


title:
Bi-Factor Approximation Algorithms for Hard Capacitated $k$-Median
  Problems

abstract:
  The $k$-Facility Location problem is a generalization of the classical
problems $k$-Median and Facility Location. The goal is to select a subset of at
most $k$ facilities that minimizes the total cost of opened facilities and
established connections between clients and opened facilities. We consider the
hard-capacitated version of the problem, where a single facility may only serve
a limited number of clients and creating multiple copies of a facility is not
allowed. We construct approximation algorithms slightly violating the
capacities based on rounding a fractional solution to the standard LP.
  It is well known that the standard LP (even in the case of uniform capacities
and opening costs) has unbounded integrality gap if we only allow violating
capacities by a factor smaller than $2$, or if we only allow violating the
number of facilities by a factor smaller than $2$. In this paper, we present
the first constant-factor approximation algorithms for the hard-capacitated
variants of the problem. For uniform capacities, we obtain a
$(2+\varepsilon)$-capacity violating algorithm with approximation ratio
$O(1/\varepsilon^2)$; our result has not yet been improved. Then, for
non-uniform capacities, we consider the case of $k$-Median, which is equivalent
to $k$-Facility Location with uniform opening cost of the facilities. Here, we
obtain a $(3+\varepsilon)$-capacity violating algorithm with approximation
ratio $O(1/\varepsilon)$.


title:
Opto-Nanomechanics Strongly Coupled to a Rydberg Superatom: Coherent vs.
  Incoherent Dynamics

abstract:
  We propose a hybrid optomechanical quantum system consisting of a moving
membrane strongly coupled to an ensemble of N atoms with a Rydberg state. Due
to the strong van-der-Waals interaction between the atoms, the ensemble forms
an effective two-level system, a Rydberg superatom, with a collectively
enhanced atom-light coupling. Using this superatom imposed collective
enhancement strong coupling between membrane and superatom is feasible for
parameters within the range of current experiments. The quantum interface to
couple the membrane and the superatom can be a pumped single mode cavity, or a
laser field in free space, where the Rydberg superatom and the membrane are
spatially separated. In addition to the coherent dynamics, we study in detail
the impact of the typical dissipation processes, in particular the radiative
decay as a source for incoherent superpositions of atomic excitations. We
identify the conditions to suppress these incoherent dynamics and thereby a
parameter regime for strong coupling. The Rydberg superatom in this hybrid
system serves as a toolbox for the nanomechanical resonator allowing for a wide
range of applications such as state transfer, sympathetic cooling and
non-classical state preparation. As an illustration, we show that a thermally
occupied membrane can be prepared in a non-classical state without the
necessity of ground state cooling.


title: Socially-Aware Networking: A Survey

abstract:
  The widespread proliferation of handheld devices enables mobile carriers to
be connected at anytime and anywhere. Meanwhile, the mobility patterns of
mobile devices strongly depend on the users' movements, which are closely
related to their social relationships and behaviors. Consequently, today's
mobile networks are becoming increasingly human centric. This leads to the
emergence of a new field which we call socially-aware networking (SAN). One of
the major features of SAN is that social awareness becomes indispensable
information for the design of networking solutions. This emerging paradigm is
applicable to various types of networks (e.g. opportunistic networks, mobile
social networks, delay tolerant networks, ad hoc networks, etc) where the users
have social relationships and interactions. By exploiting social properties of
nodes, SAN can provide better networking support to innovative applications and
services. In addition, it facilitates the convergence of human society and
cyber physical systems. In this paper, for the first time, to the best of our
knowledge, we present a survey of this emerging field. Basic concepts of SAN
are introduced. We intend to generalize the widely-used social properties in
this regard. The state-of-the-art research on SAN is reviewed with focus on
three aspects: routing and forwarding, incentive mechanisms and data
dissemination. Some important open issues with respect to mobile social sensing
and learning, privacy, node selfishness and scalability are discussed.


title:
Long-Range Magnetic Order in the 5d^2 Double Perovskite Ba2CaOsO6:
  Comparison with Spin-Disordered Ba2YReO6

abstract:
  The B-site ordered double perovskite Ba2CaOsO6 was studied by d.c. magnetic
susceptibility, powder neutron diffraction and muon spin relaxation methods.
The lattice parameter is a = 8.3619(6) A at 280K and cubic symmetry (Fm-3m) is
retained to 3.5K with a = 8.3426(5) A. Curie-Weiss susceptibility behavior is
observed for T > 100K and the derived constants are C = 0.3361(1)emu-K/mole and
T_CW = -156.2(3) K, in excellent agreement with literature values. This Curie
constant is much smaller than the spin-only value of 1.00 emu-K/mole for a 5d^2
Os6+ configuration, indicating a major influence of spin-orbit coupling.
Previous studies had detected both susceptibility and heat capacity anomalies
near 50K but no definitive conclusion was drawn concerning the nature of the
ground state. While no ordered Os moment could be detected by powder neutron
diffraction, muon spin relaxation (muSR) data show clear long-lived
oscillations indicative of long-range magnetic order below T_C = 50K. An
estimate of the ordered moment on Os6+ is ~0.2 mu_B, based upon a comparison
with muSR data for Ba2YRuO6 with a known ordered moment of 2.2 mu_B. These
results are compared with those for isostructural Ba2YReO6 which contains Re5+,
also 5d^2, and has a nearly identical unit cell constant, a = 8.3628(2) A. In
contrast, Ba2YReO6 shows T_CW = -616 K, and a complex spin-disordered and,
ultimately, spin-frozen ground state below 50 K, indicating a much higher level
of geometric frustration than in Ba2CaOsO6. A comparison is made to recent
theory on d^2 double perovskites.