title:
Relevance distributions across Bradford Zones: Can Bradfordizing improve
  search?

abstract:
  The purpose of this paper is to describe the evaluation of the effectiveness
of the bibliometric technique Bradfordizing in an information retrieval (IR)
scenario. Bradfordizing is used to re-rank topical document sets from
conventional abstracting & indexing (A&I) databases into core and more
peripheral document zones. Bradfordized lists of journal articles and
monographs will be tested in a controlled scenario consisting of different A&I
databases from social and political sciences, economics, psychology and medical
science, 164 standardized IR topics and intellectual assessments of the listed
documents. Does Bradfordizing improve the ratio of relevant documents in the
first third (core) compared to the second and last third (zone 2 and zone 3,
respectively)? The IR tests show that relevance distributions after re-ranking
improve at a significant level if documents in the core are compared with
documents in the succeeding zones. After Bradfordizing of document pools, the
core has a significant better average precision than zone 2, zone 3 and
baseline. This paper should be seen as an argument in favour of alternative
non-textual (bibliometric) re-ranking methods which can be simply applied in
text-based retrieval systems and in particular in A&I databases.


title:
Atomistic Mechanism from Vacancy Trapped H/He Atoms to Initiation of
  Bubble in W under Low Energy Ions Irradiation

abstract:
  With the first principles calculations of H and He induced energetics change
we demonstrate that in W the accumulation of H (up to 9) and He (up to 4) in a
single vacancy (V) surprisingly reduce the formation energy of first and second
nearest vacancy (as low as 0 eV), which gives the direct evidence of V-H (He)
complex mutation mechanism from V-Hn (Hen) to V2-Hn (Hen) and with the
potential to lead to the growth of H (He)-vacancy complexes: an initial step to
H and He bubble. This finding well explains the long-standing problem of why H
and He bubbles being produced on W surface exposed to low-energy (far lower
than displacement threshold energy) D or He ions irradiation. The further
identified repulsive (attractive) interaction between V-H12 (V-He14) and
additional H (He) illustrates the experimentally observed big difference of
deposition depth of H (micron) and He (100 angstrom) bubbles in W even the
migration rate of He is far larger than that of H.


title: Advanced Caching for Distributing Sensor Data through Programmable Nodes

abstract:
  This paper shows an innovative solution for distributing dynamic sensor data
by using distributed caches. Our proposal is based on the concepts of service
modularization and virtualization of network nodes made available by the
NetServ hosting environment, which has been defined and implemented with the
aim of extending the functions of the network nodes. Through a lab experiment
involving tens of nodes, we have demonstrated a significant performance
improvements in term of traffic saving and download time in comparison with a
legacy, Internet-based, approach. Beyond this performance improvements, the
proposed solution holds also functional improvements, in terms of dynamic
deployment and easy integration with services making use of sensor data.


title: Slow Stochastic Switching by Collective Chaos of Fast Elements

abstract:
  Coupled dynamical systems with one slow element and many fast elements are
analyzed. By averaging over the dynamics of the fast variables, the adiabatic
kinetic branch is introduced for the dynamics of the slow variable in the
adiabatic limit. The dynamics without the limit are found to be represented by
stochastic switching over these branches mediated by the collective chaos of
the fast elements, while the switching frequency shows a complicated dependence
on the ratio of the two timescales with some resonance structure. The ubiquity
of the phenomena in the slow--fast dynamics is also discussed.


title:
Braess's Paradox in Epidemic Game: Better Condition Results in Less
  Payoff

abstract:
  Facing the threats of infectious diseases, we take various actions to protect
ourselves, but few studies considered an evolving system with competing
strategies. In view of that, we propose an evolutionary epidemic model coupled
with human behaviors, where individuals have three strategies: vaccination,
self-protection and laissez faire, and could adjust their strategies according
to their neighbors' strategies and payoffs at the beginning of each new season
of epidemic spreading. We found a counter-intuitive phenomenon analogous to the
well-known \emph{Braess's Paradox}, namely a better condition may lead to worse
performance. Specifically speaking, increasing the successful rate of
self-protection does not necessarily reduce the epidemic size or improve the
system payoff. This phenomenon is insensitive to the network topologies, and
can be well explained by a mean-field approximation. Our study demonstrates an
important fact that a better condition for individuals may yield a worse
outcome for the society.


title:
Effective doping of carbon nanotubes in phosphor and observation of
  bright electroluminescence by field enhanced hot electron injection

abstract:
  Present work focuses on the effective doping of multi-walled carbon nanotube
(CNT) in the ZnS:Cu phosphor system and thereafter improvement in the optical
performance of electroluminescent (EL) device due to the effect of increased
local field. To facilitate doping of CNTs into the phosphor and decrease the
operating voltage of the EL device, CNTs were shortened by milling and
incorporated effectively using a flux assisted solid-state annealing reaction.
Interestingly shorter the length of CNTs used, greater was the local field
enhancement, brightness and efficiency observed for the EL devices. When the
field is applied, adequate charge carriers are tunneled into the ZnS:Cu system
through the tips of the CNTs by forming high energy hot spots thus enhancing
the local field. The improved device characteristics are due to field
enhancement without flowing of undesired current in the EL device and effective
transfer of energy from hot spots to copper activator causing field-ionization.
The detailed electrical characterization of the novel EL device along with its
brightness measurements are also presented by considering the hot electron
injection model.


title: The metric dimension of strong product graphs

abstract:
  For an ordered subset $S = \{s_1, s_2,\dots s_k\}$ of vertices and a vertex
$u$ in a connected graph $G$, the metric representation of $u$ with respect to
$S$ is the ordered $k$-tuple $ r(u|S)=(d_G(v,s_1), d_G(v,s_2),\dots,$
$d_G(v,s_k))$, where $d_G(x,y)$ represents the distance between the vertices
$x$ and $y$. The set $S$ is a metric generator for $G$ if every two different
vertices of $G$ have distinct metric representations. A minimum metric
generator is called a metric basis for $G$ and its cardinality, $dim(G)$, the
metric dimension of $G$. It is well known that the problem of finding the
metric dimension of a graph is NP-Hard. In this paper we obtain closed formulae
and tight bounds for the metric dimension of strong product graphs.


title: Structural parameters for globular clusters in M31

abstract:
  In this paper, we present surface brightness profiles for 79 globular
clusters in M31, using images observed with {\it Hubble Space Telescope}, some
of which are from new observations. The structural and dynamical parameters are
derived from fitting the profiles to several different models for the first
time. The results show that in the majority of cases, King models fit the M31
clusters as well as Wilson models, and better than S\'{e}rsic models. However,
there are 11 clusters best fitted by S\'{e}rsic models with the S\'{e}rsic
index $n>2$, meaning that they have cuspy central density profiles. These
clusters may be the well-known core-collapsed candidates. There is a bimodality
in the size distribution of M31 clusters at large radii, which is different
from their Galactic counterparts. In general, the properties of clusters in M31
and the Milky Way fall in the same regions of parameter spaces. The tight
correlations of cluster properties indicate a "fundamental plane" for clusters,
which reflects some universal physical conditions and processes operating at
the epoch of cluster formation.


title:
Quotient stacks and equivariant \'etale cohomology algebras: Quillen's
  theory revisited

abstract:
  Let $k$ be an algebraically closed field. Let $\Lambda$ be a noetherian
commutative ring annihilated by an integer invertible in $k$ and let $\ell$ be
a prime number different from the characteristic of $k$. We prove that if $X$
is a separated algebraic space of finite type over $k$ endowed with an action
of a $k$-algebraic group $G$, the equivariant \'etale cohomology algebra
$H^*([X/G],\Lambda)$, where $[X/G]$ is the quotient stack of $X$ by $G$, is
finitely generated over $\Lambda$. Moreover, for coefficients $K \in
D^+_c([X/G],\mathbb{F}_{\ell})$ endowed with a commutative multiplicative
structure, we establish a structure theorem for $H^*([X/G],K)$, involving fixed
points of elementary abelian $\ell$-subgroups of $G$, which is similar to
Quillen's theorem in the case $K = \mathbb{F}_{\ell}$. One key ingredient in
our proof of the structure theorem is an analysis of specialization of points
of the quotient stack. We also discuss variants and generalizations for certain
Artin stacks.


title:
Evolution of Robustness and Plasticity under Environmental Fluctuation:
  Formulation in terms of Phenotypic Variances

abstract:
  The characterization of plasticity, robustness, and evolvability, an
important issue in biology, is studied in terms of phenotypic fluctuations. By
numerically evolving gene regulatory networks, the proportionality between the
phenotypic variances of epigenetic and genetic origins is confirmed. The former
is given by the variance of the phenotypic fluctuation due to noise in the
developmental process; and the latter, by the variance of the phenotypic
fluctuation due to genetic mutation. The relationship suggests a link between
robustness to noise and to mutation, since robustness can be defined by the
sharpness of the distribution of the phenotype. Next, the proportionality
between the variances is demonstrated to also hold over expressions of
different genes (phenotypic traits) when the system acquires robustness through
the evolution. Then, evolution under environmental variation is numerically
investigated and it is found that both the adaptability to a novel environment
and the robustness are made compatible when a certain degree of phenotypic
fluctuations exists due to noise. The highest adaptability is achieved at a
certain noise level at which the gene expression dynamics are near the critical
state to lose the robustness. Based on our results, we revisit Waddington's
canalization and genetic assimilation with regard to the two types of
phenotypic fluctuations.


title: The myths of the Bear

abstract:
  Following previous works on ancient myths in Greek and Latin literature
regarding Ursa Major, and the possible relation with the ancient shape of the
constellation, we discuss further this case in the light of the evolution of
Homo sapiens and the ethnographic records of populations of Eurasia and North
America.


title:
Synthesis of Long-T1 Silicon Nanoparticles for Hyperpolarized 29Si
  Magnetic Resonance Imaging

abstract:
  We describe the synthesis, materials characterization and dynamic nuclear
polarization (DNP) of amorphous and crystalline silicon nanoparticles for use
as hyperpolarized magnetic resonance imaging (MRI) agents. The particles were
synthesized by means of a metathesis reaction between sodium silicide (Na4Si4)
and silicon tetrachloride (SiCl4) and were surface functionalized with a
variety of passivating ligands. The synthesis scheme results in particles of
diameter ~10 nm with long size-adjusted 29Si spin lattice relaxation (T1) times
(> 600 s), which are retained after hyperpolarization by low temperature DNP.


title: 3-3-1-1 model for dark matter

abstract:
  We show that the SU(3)_C X SU(3)_L X U(1)_X (3-3-1) model of strong and
electroweak interactions can naturally accommodate an extra U(1)_N symmetry
behaving as a gauge symmetry. Resulting theory based on SU(3)_C X SU(3)_L X
U(1)_X X U(1)_N (3-3-1-1) gauge symmetry realizes B-L=-(2/\sqrt{3})T_8+N as a
charge of SU(3)_L X U(1)_N. Consequently, a residual symmetry, W-parity,
resulting from broken B-L in similarity to R-parity in supersymmetry is always
conserved and may be unbroken. There is a specific fermion content recently
studied in which all new particles that have wrong lepton-numbers are odd under
W-parity, while the standard model particles are even. Therefore, the lightest
wrong-lepton particle (LWP) responsible for dark matter is naturally
stabilized. We explicitly show that the non-Hermitian neutral gauge boson (X^0)
as LWP cannot be a dark matter. However, the LWP as a new neutral fermion (N_R)
can be dark matter if its mass is in range 1.9 TeV \leq m_{N_R} \leq 2.5 TeV,
provided that the new neutral gauge boson (Z') mass satisfies 2.2 TeV \leq m_Z'
\leq 2.5 TeV. Moreover, the scalar dark matter candidate (H'\simeq \eta_3)
which has traditionally been studied is only stabilized by W-parity. All the
unwanted interactions and vacuums as often encountered in the 3-3-1 model are
naturally suppressed. And, the standing issues on tree-level flavor changing
neutral currents and CPT violation also disappear.


title:
Non-Gaussian Fluctuation and Non-Markovian Effect in the Nuclear Fusion
  Process: Langevin Dynamics Emerging from Quantum Molecular Dynamics
  Simulations

abstract:
  Macroscopic parameters as well as precise information on the random force
characterizing the Langevin type description of the nuclear fusion process
around the Coulomb barrier are extracted from the microscopic dynamics of
individual nucleons by exploiting the numerical simulation of the improved
quantum molecular dynamics. It turns out that the dissipation dynamics of the
relative motion between two fusing nuclei is caused by a non-Gaussian
distribution of the random force. We find that the friction coefficient as well
as the time correlation function of the random force takes particularly large
values in a region a little bit inside of the Coulomb barrier. A clear
non-Markovian effect is observed in the time correlation function of the random
force. It is further shown that an emergent dynamics of the fusion process can
be described by the generalized Langevin equation with memory effects by
appropriately incorporating the microscopic information of individual nucleons
through the random force and its time correlation function.


title: The r-process in proto-neutron-star wind revisited

abstract:
  We examine the r-process in the neutrino-driven proto-neutron-star (PNS) wind
of core-collapse supernovae in light of the recent findings of massive neutron
stars in binaries as well as of an indication of neutron-richness in the PNS
ejecta because of the nucleon potential corrections on neutrino opacities. To
this end, a spherically symmetric, general relativistic, steady-state wind
model is applied for a wide range of PNS masses between 1.2 M_sun and 2.4 M_sun
with the latter reaching the causality limit. Nucleosynthesis calculations with
these PNS models are performed by assuming a time evolution of electron
fraction with its minimal value of Y_e = 0.4, which mimics recent
hydrodynamical results. The fundamental nucleosynthetic aspect of the PNS wind
is found to be the production of Sr, Y and Zr in quasi-equilibrium and of the
elements with A = 90-110 by a weak r-process, which can be an explanation for
the abundance signatures in r-process-poor Galactic halo stars. PNSs more
massive than 2.0 M_sun can eject heavy r-process elements, however, with
substantially smaller amount than what is needed to account for the solar
content. PNS winds can be thus the major origin of light trans-iron elements
but no more than 10% of those heavier than A ~ 110, although they may be the
sources of the low-level abundances of Sr and Ba found in numerous metal-poor
stars if the maximum mass of PNS exceeds 2.0 M_sun.


title: Exact periodic and solitonic states in the spinor condensates

abstract:
  We propose a method to analytically solve the one-dimensional coupled
nonlinear Gross-Pitaevskii equations which govern the motion of the spinor
Bose-Einstein condensates. In a uniform external potential, the Hamiltonian
comprises the kinetic energy, the linear and the quadratic Zeeman energies.
Several classes of exact periodic and solitonic solutions, either in real or in
complex forms, are obtained for both the F=1 and F=2 condensates. These
solutions are general that contain neither approximations nor constraints on
the system parameters.


title:
Gaussian Quadrature and Lattice Discretization of the Fermi-Dirac
  Distribution for Graphene

abstract:
  We construct a lattice kinetic scheme to study electronic flow in graphene.
For this purpose, we first derive a basis of orthogonal polynomials, using as
weight function the ultrarelativistic Fermi-Dirac distribution at rest. Later,
we use these polynomials to expand the respective distribution in a moving
frame, for both cases, undoped and doped graphene. In order to discretize the
Boltzmann equation and make feasible the numerical implementation, we reduce
the number of discrete points in momentum space to 18 by applying a Gaussian
quadrature, finding that the family of representative wave (2+1)-vectors, that
satisfies the quadrature, reconstructs a honeycomb lattice. The procedure and
discrete model are validated by solving the Riemann problem, finding excellent
agreement with other numerical models. In addition, we have extended the
Riemann problem to the case of different dopings, finding that by increasing
the chemical potential, the electronic fluid behaves as if it increases its
effective viscosity.


title: Uniformly counting rational points on conics

abstract:
  We provide an asymptotic estimate for the number of rational points of
bounded height on a non-singular conic over the rationals. The estimate is
uniform in the coefficients of the underlying quadratic form.


title: Feller Evolution Systems: Generators and Approximation

abstract:
  A time and space inhomogeneous Markov process is a Feller evolution process,
if the corresponding evolution system on the continuous functions vanishing at
infinity is strongly continuous. We discuss generators of such systems and show
that under mild conditions on the generators a Feller evolution can be
approximated by Markov chains with L\'evy increments.
  The result is based on the approximation of the time homogeneous space-time
process corresponding to a Feller evolution process. In particular, we show
that a $d$-dimensional Feller evolution corresponds to a $d+1$-dimensional
Feller process. It is remarkable that, in general, this Feller process has a
generator with discontinuous symbol.


title:
Disordered exclusion process revisited: some exact results in the
  low-current regime

abstract:
  We study steady state of the totally asymmetric simple exclusion process with
inhomogeneous hopping rates associated with sites (site-wise disorder). Using
the fact that the non-normalized steady-state weights which solve the master
equation are polynomials in all the hopping rates, we propose a general method
for calculating their first few lowest coefficients exactly. In case of binary
disorder where all slow sites share the same hopping rate r<1, we apply this
method to calculate steady-state current up to the quadratic term in r for some
particular disorder configurations. For the most general (non-binary) disorder,
we show that in the low-current regime the current is determined solely by the
current-minimizing subset of equal hopping rates, regardless of other hopping
rates. Our approach can be readily applied to any other driven diffusive system
with unidirectional hopping if one can identify a hopping rate such that the
current vanishes when this rate is set to zero.


title:
A Comparison between Two Main Academic Literature Collections: Web of
  Science and Scopus Databases

abstract:
  Nowadays, the worlds scientific community has been publishing an enormous
number of papers in different scientific fields. In such environment, it is
essential to know which databases are equally efficient and objective for
literature searches. It seems that two most extensive databases are Web of
Science and Scopus. Besides searching the literature, these two databases used
to rank journals in terms of their productivity and the total citations
received to indicate the journals impact, prestige or influence. This article
attempts to provide a comprehensive comparison of these databases to answer
frequent questions which researchers ask, such as: How Web of Science and
Scopus are different? In which aspects these two databases are similar? Or, if
the researchers are forced to choose one of them, which one should they prefer?
For answering these questions, these two databases will be compared based on
their qualitative and quantitative characteristics.


title:
Two Remarks on the Local Behavior of Solutions to Logarithmically
  Singular Diffusion Equations and its Porous-Medium Type Approximations

abstract:
  For the logarithmically singular parabolic equation \[ u_t-\Delta\ln
u=0\qquad\text{weakly in}\ \ E\times(0,T], \] we establish a Harnack type
estimate in the $L^1_{loc}$ topology, and we show that the solutions are
locally analytic in the space variables and differentiable in time. The main
assumption is that $\ln u$ possesses a sufficiently high degree of
integrability, namely \begin{equation*} \ln u\in
L^\infty_{loc}\big(0,T;L^p_{loc}(E)\big) \quad\text{for some} p\ge1.
\end{equation*} These two properties are known for solutions of singular porous
medium type equations ($0<m<1$), which formally approximate the logarithmically
singular equation. However, the corresponding estimates deteriorate as $m\to0$.
It is shown that these estimates become stable and carry to the limit as
$m\to0$, provided the indicated sufficiently high order of integrability is in
force. The latter then appears as the discriminating assumption between
solutions of parabolic equations with power-like singularities and logarithmic
singularities to insure such solutions to be regular.


title: Does Criticisms Overcome the Praises of Journal Impact Factor?

abstract:
  Journal impact factor (IF) as a gauge of influence and impact of a particular
journal comparing with other journals in the same area of research, reports the
mean number of citations to the published articles in particular journal.
Although, IF attracts more attention and being used more frequently than other
measures, it has been subjected to criticisms, which overcome the advantages of
IF. Critically, extensive use of IF may result in destroying editorial and
researchers behaviour, which could compromise the quality of scientific
articles. Therefore, it is the time of the timeliness and importance of a new
invention of journal ranking techniques beyond the journal impact factor.


title: Some remarks on non-commutative principal ideal rings

abstract:
  We prove some algebraic results on the ring of matrix differential operators
over a differential field in the generality of non-commutative principal ideal
rings. These results are used in the theory of non-local Poisson structures.


title:
Higgs Amplitude Mode in BCS Superconductors Nb$_{1-x}$Ti$_{x}$N induced
  by Terahertz Pulse Excitation

abstract:
  Ultrafast responses of BCS superconductor Nb1-xTixN films in a nonadiabatic
excitation regime were investigated by using terahertz (THz) pump-THz probe
spectroscopy. After an instantaneous excitation with the monocycle THz pump
pulse, a transient oscillation emerges in the electromagnetic response in the
BCS gap energy region. The oscillation frequency coincides with the asymptotic
value of the BCS gap energy, indicating the appearance of the
theoretically-anticipated collective amplitude mode of the order parameter,
namely the Higgs amplitude mode. Our result opens a new pathway to the
ultrafast manipulation of the superconducting order parameter by optical means.


title: Surfaces with a common asymptotic curve in Minkowski 3-space

abstract:
  In this paper, we express surfaces parametrically through a given spacelike
(timelike) asymptotic curve using the Frenet frame of the curve in Minkowski
3-space. Necessary and sufficient conditions for the coefficients of the Frenet
frame to satisfy both parametric and asymptotic requirements are derived. We
also present some interesting examples to show the validity of this study.


title:
An Algebraic Topological Construct of Classical Loop Gravity and the
  prospect of Higher Dimensions

abstract:
  In this paper, classical gravity is reformulated in terms of loops, via an
algebraic topological approach. The main component is the loop group, whose
elements consist of pairs of cobordant loops. A Chas-Sullivan product is
described on the cobordism, and three other products, namely the 'vertical',
'horizontal' and 'total' products are re-introduced. (They have already been
defined in an earlier paper by the author). A loop calculus is introduced on
the space of loops, consisting of the loop variation functional,the loop
derivative, Mandelstam derivative, and what the author wishes to call, the
Gambini-Pullin contact functional. The loop derivative happens to be a
generator of the group of loops, and the Gambini-Pullin functional is an
infinitesimal generator of diffeomorphisms. A toy model of gravity is
formulated in terms of the above, and it is proven that the total product
provides for the Maurer-Cartan structure of the space. Further, new quantities
labeled as 'momenta', 'velocity' and 'energy' are introduced in terms of the
loop products and loop derivatives. The prospect of re-constructing general
relativity in higher dimensions is explored, with the 'momenta' and 'velocity'
being the basic loop variables. In the process, it is proven that the 'momenta'
and 'velocity' behave as cobordant loops in higher dimensions.


title:
Optimal Distributed Scheduling in Wireless Networks under the SINR
  interference model

abstract:
  Radio resource sharing mechanisms are key to ensuring good performance in
wireless networks. In their seminal paper \cite{tassiulas1}, Tassiulas and
Ephremides introduced the Maximum Weighted Scheduling algorithm, and proved its
throughput-optimality. Since then, there have been extensive research efforts
to devise distributed implementations of this algorithm. Recently, distributed
adaptive CSMA scheduling schemes \cite{jiang08} have been proposed and shown to
be optimal, without the need of message passing among transmitters. However
their analysis relies on the assumption that interference can be accurately
modelled by a simple interference graph. In this paper, we consider the more
realistic and challenging SINR interference model. We present {\it the first
distributed scheduling algorithms that (i) are optimal under the SINR
interference model, and (ii) that do not require any message passing}. They are
based on a combination of a simple and efficient power allocation strategy
referred to as {\it Power Packing} and randomization techniques. We first
devise algorithms that are rate-optimal in the sense that they perform as well
as the best centralized scheduling schemes in scenarios where each transmitter
is aware of the rate at which it should send packets to the corresponding
receiver. We then extend these algorithms so that they reach
throughput-optimality.


title: Differential HBT Method to Analyze Rotation

abstract:
  Two particle correlations are studied in the reaction plane of peripheral
relativistic heavy ion reactions where the initial state has substantial
angular momentum. The earlier predicted rotation effect and Kelvin Helmholtz
Instability, leads to space-time momentum correlations among the emitted
particles. A specific combination of two particle correlation measurements is
proposed, which can sensitively detect the rotation of the emitting system.
Here the method is presented in simple few source models where the symmetries
and the possibilities of the detection can be demonstrated in a transparent
way.


title: Monte Carlo Tests of Nucleation Concepts in the Lattice Gas Model

abstract:
  The conventional theory of homogeneous and heterogeneous nucleation in a
supersaturated vapor is tested by Monte Carlo simulations of the lattice gas
(Ising) model with nearest-neighbor attractive interactions on the simple cubic
lattice. The theory considers the nucleation process as a slow (quasi-static)
cluster (droplet) growth over a free energy barrier $\Delta F^*$, constructed
in terms of a balance of surface and bulk term of a "critical droplet" of
radius $R^*$, implying that the rates of droplet growth and shrinking
essentially balance each other for droplet radius $R=R^*$. For heterogeneous
nucleation at surfaces, the barrier is reduced by a factor depending on the
contact angle. Using the definition of "physical" clusters based on the
Fortuin-Kasteleyn mapping, the time-dependence of the cluster size distribution
is studied for "quenching experiments" in the kinetic Ising model, and the
cluster size $\ell ^*$ where the cluster growth rate changes sign is estimated.
These studies of nucleation kinetics are compared to studies where the relation
between cluster size and supersaturation is estimated from equilibrium
simulations of phase coexistence between droplet and vapor in the canonical
ensemble. The chemical potential is estimated from a lattice version of the
Widom particle insertion method. For large droplets it is shown that the
"physical clusters" have a volume consistent with the estimates from the lever
rule. "Geometrical clusters" (defined such that each site belonging to the
cluster is occupied and has at least one occupied neighbor site) yield valid
results only for temperatures less than 60% of the critical temperature, where
the cluster shape is non-spherical. We show how the chemical potential can be
used to numerically estimate $\Delta F^*$ also for non-spherical cluster
shapes.


title: Hadroproduction in heavy-ion collisions

abstract:
  The shapes of invariant differential cross section for charged particle
production as function of transverse momentum measured in heavy-ion collisions
are analyzed. The data measured at RHIC and LHC are treated as function of
energy density according to a recent theoretical approach. The Boltzmann-like
statistical distribution is extracted from the whole statistical ensemble of
produced hadrons using the introduced model. Variation of the temperature,
characterizing this exponential distribution, is studied as function of energy
density.


title: Proton and Lambda-Hyperon Production in Nucleus-Nucleus Collisions

abstract:
  The experimental data on net proton and net Lambda-hyperon spectra obtained
by the NA35 Collaboration, as well as the inclusive densities of Lambda and
bar-Lambda obtained by NA49, NA57, and STAR collaborations, are compared with
the predictions of the Quark-Gluon String Model. The contributions of String
Junction diffusion, interactions with nuclear clusters, and the inelastic
screening corrections are accounted for. The level of numerical agreement of
the calculations with the experimental data is of about 20-30%. The predictions
for LHC are also presented.


title: On the H-triangle of generalised nonnesting partitions

abstract:
  To a crystallographic root system \Phi, and a positive integer k, there are
associated two Fuss-Catalan objects, the set of nonnesting partitions
NN^(k)(\Phi), and the cluster complex \Delta^(k)(\Phi). These posess a number
of enumerative coincidences, many of which are captured in a surprising
identity, first conjectured by Chapoton for k=1 and later generalized to k>1 by
Armstrong. We prove this conjecture, obtaining some structural and enumerative
results on NN^(k)(\Phi) along the way, including an earlier conjecture by Fomin
and Reading giving a refined enumeration by Fu{\ss}-Narayana numbers.


title:
Density Functional Theory for Superconductors with Particle-hole
  Asymmetric Electronic Structure

abstract:
  To extend the applicability of density functional theory for superconductors
(SCDFT) to systems with significant particle-hole asymmetry, we construct a new
exchange-correlation kernel entering the gap equation. We show that the kernel
is numerically stable and does not diverge even in the low temperature limit.
Solving the gap equation for model systems with the present kernel analytically
and numerically, we find that the asymmetric component of electronic density of
states, which has not been considered with the previous kernel, systematically
decreases transition temperature (Tc). We present a case where the decrease of
Tc amounts to several tens of percent.


title: Electrically Dressed Ultralong-Range Polar Rydberg Molecules

abstract:
  We investigate the impact of an electric field on the structure of
ultralong-range polar diatomic Rydberg molecules. Both the s-wave and p-wave
interactions of the Rydberg electron and the neutral ground state atom are
taken into account. In the presence of the electric field the angular degree of
freedom between the electric field and the internuclear axis acquires
vibrational character and we encounter two-dimensional oscillatory adiabatic
potential energy surfaces with an antiparallel equilibrium configuration. The
electric field allows to shift the corresponding potential wells in such a
manner that the importance of the p-wave interaction can be controlled and the
individual wells are energetically lowered at different rates. As a consequence
the equilibrium configuration and corresponding energetically lowest well move
to larger internuclear distances for increasing field strength. For strong
fields the admixture of non-polar molecular Rydberg states leads to the
possibility of exciting the large angular momentum polar states via two-photon
processes from the ground state of the atom. The resulting properties of the
electric dipole moment and the vibrational spectra are analyzed with varying
field strength.


abstract:
  L-function and rational points on an elliptic curve via the classical number
theory.


title: An exercise on Gauss' law for gravitation: The Flat Earth model

abstract:
  We discuss the flat and hollow models of the Earth as a pedagogical example
of the application of Gauss' law to the gravitational field.


title: Relational Evolution of Observables for Hamiltonian-Constrained Systems

abstract:
  Evolution of systems in which Hamiltonians are generators of gauge
transformations is a notion that requires more structure than the canonical
theory provides. We identify and study this additional structure in the
framework of relational observables ("partial observables"). We formulate
necessary and sufficient conditions for the resulting evolution in the physical
phase space to be a symplectomorphism. We give examples which satisfy those
conditions and examples which do not. We point out that several classic
positions in the literature on relational observables contain an incomplete
approach to the issue of evolution and false statements. Our work provides
useful clarification and opens the door to studying correctly formulated
definitions.


title: Tensor Decompositions: A New Concept in Brain Data Analysis?

abstract:
  Matrix factorizations and their extensions to tensor factorizations and
decompositions have become prominent techniques for linear and multilinear
blind source separation (BSS), especially multiway Independent Component
Analysis (ICA), NonnegativeMatrix and Tensor Factorization (NMF/NTF), Smooth
Component Analysis (SmoCA) and Sparse Component Analysis (SCA). Moreover,
tensor decompositions have many other potential applications beyond multilinear
BSS, especially feature extraction, classification, dimensionality reduction
and multiway clustering. In this paper, we briefly overview new and emerging
models and approaches for tensor decompositions in applications to group and
linked multiway BSS/ICA, feature extraction, classification andMultiway Partial
Least Squares (MPLS) regression problems. Keywords: Multilinear BSS, linked
multiway BSS/ICA, tensor factorizations and decompositions, constrained Tucker
and CP models, Penalized Tensor Decompositions (PTD), feature extraction,
classification, multiway PLS and CCA.


title: Differential HBT Applied to Relativistic Fluid Dynamics

abstract:
  The earlier introduced Differential HBT method aiming for detecting rotation
is used to analyze the fluid dynamical model results of ultra-relativistic
heavy ion reactions where the initial state has substantial angular momentum.
The rotation effect and Kelvin Helmholtz Instability, lead to space-time
momentum correlations, which can be detected by the method.


title:
Invariant expectation values in the sampling of discrete frequency
  distributions

abstract:
  The general relationship between an arbitrary frequency distribution and the
expectation value of the frequency distributions of its samples is discussed. A
wide set of measurable quantities ("invariant moments") whose expectation value
does not in general depend on the size of the sample is constructed and
illustrated by applying the results to Ewens sampling formula. Invariant
moments are especially useful in the sampling of systems characterized by the
absence of an intrinsic scale. Distribution functions that may parametrize the
samples of scale-free distributions are considered and their invariant
expectation values are computed. The conditions under which the scaling limit
of such distributions may exist are described.


title:
Time dependence of charge losses at the Si-SiO2 interface in p+n-silicon
  strip sensors

abstract:
  The collection of charge carriers generated in p+n strip sensors close to the
Si-SiO2 interface before and after 1 MGy of X-ray irradiation has been
investigated using the transient current technique with sub-nanosecond focused
light pulses of 660 nm wavelength, which has an absorption length of 3.5 um in
silicon at room temperature. The paper describes the measurement and analysis
techniques used to determine the number of electrons and holes collected.
Depending on biasing history, humidity and irradiation, incomplete collection
of either electrons or holes is observed. The charge losses change with time.
The time constants are different for electrons and holes and increase by two
orders of magnitude when reducing the relative humidity from about 80 % to less
than 1 %. An attempt to interpret these results is presented.


title:
On Green's functions for Hamiltonians with potentials possessing
  singularity at the origin: application to the zero-range potential formalism

abstract:
  We evaluate the short-range asymptotic behavior of Green's function for a
Hamiltonian when its potential energy part has an inverse power singularity at
the origin. The analytically solvable case of sharply screened Coulomb
potential is considered firstly. For this potential the additional logarithmic
singular term has been found in the short-range asymptote of the Green function
as in the case of the pure Coulomb potential. The case of a short-range
potential of an arbitrary form with inverse power singularity is treated on the
basis of the integral Lippmann-Schwinger equation. It is shown that, if the
singularity is weaker than the Coulomb one, the Green function has only
standard singularity. For the case of $r^{-\rho}$ singularity of the potential
with $1\le\rho<2$ the additional singularity in the asymptotic behavior of the
Green function appears. In the case of $\rho=1$ the additional logarithmic
singularity has the same form as in the case of the pure Coulomb potential. In
the case of $1<\rho<2$ the additional singularity of the Green function has the
form of the polar singularity $r^{-\rho+1}$. These results are applied for
extending the zero-range potential formalism on Hamiltonians with singular
potentials.


title: On Ultrahigh-energy Neutrino Scattering

abstract:
  We predict the neutrino-nucleon cross section at ultrahigh energies relevant
in connection with the search for high-energy cosmic neutrinos. Our
investigation, employing the color-dipole picture, among other things allows us
to quantitatively determine which fraction of the ultrahigh-energy
neutrino-nucleon cross section stems from the saturation versus the
color-transparency region. We disagree with various results in the literature
that predict a strong suppression of the neutrino-nucleon cross section at
neutrino energies above $E \cong 10^9 GeV$. Suppression in the sense of a
diminished increase of the neutrino-nucleon cross section with energy only
starts to occur at neutrino energies beyond $E \cong 10^{14} GeV$.


title:
The CDEX-1 1 kg Point-Contact Germanium Detector for Low Mass Dark
  Matter Searches

abstract:
  The CDEX Collaboration has been established for direct detection of light
dark matter particles, using ultra-low energy threshold p-type point-contact
germanium detectors, in China JinPing underground Laboratory (CJPL). The first
1 kg point-contact germanium detector with a sub-keV energy threshold has been
tested in a passive shielding system located in CJPL. The outputs from both the
point-contact p+ electrode and the outside n+ electrode make it possible to
scan the lower energy range of less than 1 keV and at the same time to detect
the higher energy range up to 3 MeV. The outputs from both p+ and n+ electrode
may also provide a more powerful method for signal discrimination for dark
matter experiment. Some key parameters, including energy resolution, dead time,
decay times of internal X-rays, and system stability, have been tested and
measured. The results show that the 1 kg point-contact germanium detector,
together with its shielding system and electronics, can run smoothly with good
performances. This detector system will be deployed for dark matter search
experiments.


title: Constant Speed Ramps

abstract:
  In this paper we show all possible ramps where an object can move with
constant speed under the effect of gravity and friction. The planar ramp are
very easy to describe, just rotate a curve with velocity vector
(tanh(as),sech(as)). Recall that tanh(as)^2+sech^2(as) = 1. Therefore, the
solution of the planar constant speed problem is connected with easy to
describe examples of curves with arc-length parameter. For ramps in the space,
we show that there are as many ramps as tangent unit vector fields in the south
hemisphere. A video explaining these results can be found at
http://www.youtube.com/watch?v=iBrvbb0efVk

categories: math.DG math-ph math.DS math.MP physics.class-ph


title: Vortex ring generation during drop impact into a shallow pool

abstract:
  When a drop falls from a moderate height into a shallow fluid pool whose
depth is of the order of the drop-radius two pairs of vortex rings are
generated. The inner pair forms at the edge of the crater created by the
impacting drop while the outer pair is laid off from the spreading wave. One
ring of each of these pairs is short-lived while the other persists. Each of
the rings has a measureable non-zero circulation (whose sign, however, is
opposite to that of the well-known deep-water drop vortex rings) which persists
long after the wave has receded. Furthermore under certain conditions they
develop instabilities typical to ring vortices. Although the rings are well
reproducible, aspects of their later development are very sensitive to changes
in some of the experimental parameters. This paper reports on experiments
distinguishing reproducible aspects of these drop- generated rings and
documenting their dependence on material and geometrical parameters.


title:
Dispersion dynamics for the defocusing generalized Korteweg-de Vries
  equation

abstract:
  We study dispersion for the defocusing gKdV equation. It is expected that it
is not possible for the bulk of the $L^2-$mass to concentrate in a small
interval for a long time. We study a variance-type functional exploiting Tao's
monotonicity formula in the spirit of earlier work by Tao as well as Kwon &
Shao and quantify its growth in terms of sublevel estimates.


title: Currents and pseudomagnetic fields in strained graphene rings

abstract:
  We study the effects of strain on the electronic properties and persistent
current characteristics of a graphene ring using the Dirac representation. For
a slightly deformed graphene ring flake, one obtains sizable pseudomagnetic
(gauge) fields that may effectively reduce or enhance locally the applied
magnetic flux through the ring. Flux-induced persistent currents in a flat ring
have full rotational symmetry throughout the structure; in contrast, we show
that currents in the presence of a circularly symmetric deformation are
strongly inhomogeneous, due to the underlying symmetries of graphene. This
result illustrates the inherent competition between the `real' magnetic field
and the `pseudo' field arising from strains, and suggest an alternative way to
probe the strength and symmetries of pseudomagnetic fields on graphene systems.


title: Optimal Potentials For Schrodinger Operators

abstract:
  We consider the Schrodinger operator a given domain. Our goal is to study
some optimization problems where an optimal (non-negative) potential V has to
be determined in some suitable admissible classes and for some suitable
optimization criteria, like the energy or the Dirichlet eigenvalues.


title: Moufang sets of mixed type F4

abstract:
  Moufang sets were introduced by Jacques Tits in order to understand isotropic
linear algebraic groups of relative rank one, but the notion is more general.
We describe a new class of Moufang sets, arising from so-called mixed groups of
type F4 in characteristic 2, obtained as the fixed point set under a suitable
involution.


title:
Interaction-disorder competition in a spin system evaluated through the
  Loschmidt Echo

abstract:
  The interplay between interactions and disorder in closed quantum many-body
systems is relevant for thermalization phenomenon. In this article, we address
this competition in an infinite temperature spin system, by means of the
Loschmidt echo (LE), which is based on a time reversal procedure. This quantity
has been formerly employed to connect quantum and classical chaos, and in the
present many-body scenario we use it as a dynamical witness. We assess the LE
time scales as a function of disorder and interaction strengths. The strategy
enables a qualitative phase diagram that shows the regions of ergodic and
nonergodic behavior of the polarization under the echo dynamics.


title:
Detecting Topological Entanglement Entropy in a Lattice of Quantum
  Harmonic Oscillators

abstract:
  The Kitaev surface-code model is the most studied example of a topologically
ordered phase and typically involves four-spin interactions on a
two-dimensional surface. A universal signature of this phase is topological
entanglement entropy (TEE), but due to low signal to noise, it is extremely
difficult to observe in these systems, and one usually resorts to measuring
anyonic statistics of excitations or non-local string operators to reveal the
order. We describe a continuous-variable analog to the surface code using
quantum harmonic oscillators on a two-dimensional lattice, which has the
distinctive property of needing only two-body nearest-neighbor interactions for
its creation. Though such a model is gapless, satisfies an area law, and the
ground state can be simply prepared by measurements on a finitely squeezed and
gapped two-dimensional cluster state, which does not have topological order.
Asymptotically, the TEE grows linearly with the squeezing parameter, and we
show that its mixed-state generalization, the topological mutual information,
is robust to some forms of state preparation error and can be detected simply
using single-mode quadrature measurements. Finally, we discuss scalable
implementation of these methods using optical and circuit-QED technology.


title:
Exact Quantum Correlations of Conjugate Variables From Joint Quadrature
  Measurements

abstract:
  We demonstrate that for two canonically conjugate operators $\hat{q},\hat {p}
$,the global correlation $\langle \hat{q} \hat {p} + \hat{p} \hat {q} \rangle
-2 \langle \hat{q}\rangle \langle \hat {p}\rangle$, and the local correlations
$\langle \hat{q} \rangle (p) - \langle \hat{q}\rangle$ and $\langle \hat{p}
\rangle (q)-\langle \hat {p}\rangle$ can be measured exactly by Von
Neumann-Arthurs-Kelly joint quadrature measurements . These correlations
provide a sensitive experimental test of quantum phase space probabilities
quite distinct from the probability densities of $ q,p $. E.g. for EPR states,
and entangled generalized coherent states, phase space probabilities which
reproduce the correct position and momentum probability densities have to be
modified to reproduce these correlations as well.


title:
Parametric Representation of a Hypersurface Family With a Common Spatial
  Geodesic

abstract:
  In this paper, we study the problem of finding a hypersurface family from a
given spatial geodesic curve in R4. We obtain the parametric representation for
a hypersurface family whose members have the same curve as a given geodesic
curve. Using the Frenet frame of the given geodesic curve, we present the
hypersurface as a linear combination of this frame and analyse the necessary
and sufficient condition for that curve to be geodesic. We illustrate this
method by presenting some examples.


title:
Filter Design with Secrecy Constraints: The MIMO Gaussian Wiretap
  Channel

abstract:
  This paper considers the problem of filter design with secrecy constraints,
where two legitimate parties (Alice and Bob) communicate in the presence of an
eavesdropper (Eve), over a Gaussian multiple-input-multiple-output (MIMO)
wiretap channel. This problem involves designing, subject to a power
constraint, the transmit and the receive filters which minimize the
mean-squared error (MSE) between the legitimate parties whilst assuring that
the eavesdropper MSE remains above a certain threshold. We consider a general
MIMO Gaussian wiretap scenario, where the legitimate receiver uses a linear
Zero-Forcing (ZF) filter and the eavesdropper receiver uses either a ZF or an
optimal linear Wiener filter. We provide a characterization of the optimal
filter designs by demonstrating the convexity of the optimization problems. We
also provide generalizations of the filter designs from the scenario where the
channel state is known to all the parties to the scenario where there is
uncertainty in the channel state. A set of numerical results illustrates the
performance of the novel filter designs, including the robustness to channel
modeling errors. In particular, we assess the efficacy of the designs in
guaranteeing not only a certain MSE level at the eavesdropper, but also in
limiting the error probability at the eavesdropper. We also assess the impact
of the filter designs on the achievable secrecy rates. The penalty induced by
the fact that the eavesdropper may use the optimal non-linear receive filter
rather than the optimal linear one is also explored in the paper.


title: Permanent market impact can be nonlinear

abstract:
  There are two schools of thought regarding market impact modeling. On the one
hand, seminal papers by Almgren and Chriss introduced a decomposition between a
permanent market impact and a temporary (or instantaneous) market impact. This
decomposition is used by most practitioners in execution models. On the other
hand, recent research advocates for the use of a new modeling framework that
goes down to the resilient dynamics of order books: transient market impact.
One of the main criticisms against permanent market impact is that it has to be
linear to avoid dynamic arbitrage. This important discovery made by Huberman
and Stanzl and Gatheral favors the transient market impact framework, as linear
permanent market impact is at odds with reality. In this paper, we reconsider
the point made by Gatheral using a simple model for market impact and show that
permanent market impact can be nonlinear. Also, and this is the most important
part from a practical point of view, we propose different statistics to
estimate permanent market impact and execution costs that generalize the ones
proposed in Almgren at al. (2005).


title: On Recognition by Order and Degree Pattern of Finite Simple Groups

abstract:
  Let ${\rm GK}(G)$ be the prime graph associated with a finite group $G$ and
$D(G)$ be the degree pattern of $G$. A finite group $G$ is said to be $k$-fold
OD-characterizable if there exist exactly $k$ non-isomorphic groups $H$ such
that $|H|=|G|$ and $D(H)=D(G)$. A 1-fold OD-characterizable group is simply
called OD-characterizable. The purpose of this paper is threefold. First, it
provides the reader with a few useful and efficient tools on
OD-characterizability of finite groups. Second, it lists a number of such
simple groups that have been already investigated. Third, it shows that the
simple groups $L_6(3)$ and $U_4(5)$ are OD-characterizable, too.


title:
A new quantitative two weight theorem for the Hardy-Littlewood maximal
  operator

abstract:
  A quantitative two weight theorem for the Hardy-Littlewood maximal operator
is proved improving the known ones. As a consequence a new proof of the main
results in [HP] and in [HPR12] is obtained which avoids the use of the sharp
quantitative reverse Holder inequality for $A_{\infty}$ proved in those papers.
Our results are valid within the context of spaces of homogeneous type without
imposing the non-empty annuli condition.


title:
Far off-Bragg reconstruction of volume holographic gratings: A
  comparison of experiment and theories

abstract:
  We performed light optical diffraction experiments on a nanoparticle-polymer
volume holographic grating in an angular range including also far off-Bragg
replay. A comparison of three diffraction theories - on the same level of
complexity - with our experimental results shows that the dynamical theory of
diffraction and the first-order two-wave coupling theory using the beta-value
method fit the data very well. In contrast, the prevalent two-wave coupling
theory using the K-vector closure method yields a poor fit with an order of
magnitude worse mean squared error. These findings must be considered for
accurate determination of coupling strength and grating thickness.


title:
Dynamics of correlated transfer-ionization in collisions with a fast
  highly charged ion

abstract:
  Transfer-ionization in fast collisions between a bare ion and an atom, in
which one of the atomic electrons is captured by the ion whereas another one is
emitted, crucially depends on dynamic electron-electron correlations. We show
that in collisions with a highly charged ion a strong field of the ion has a
very profound effect on the correlated channels of transfer-ionization. In
particular, this field weakens electron emission into the direction opposite to
the motion of the ion and strongly suppresses the emission perpendicular to
this motion. Instead, electron emission is redirected into those parts of the
momentum space which are very weakly populated in fast collisions with low
charged ions.


title:
Structure identification and state initialization of spin networks with
  limited access

abstract:
  For reliable and consistent quantum information processing carried out on a
quantum network, the network structure must be fully known and a desired
initial state must be accurately prepared on it. In this paper, for a class of
spin networks with its single node only accessible, we provide two
continuous-measurement-based methods to achieve the above requirements; the
first one identifies the unknown network structure with high probability, based
on continuous-time Bayesian update of the graph structure; the second one is,
with the use of adaptive measurement technique, able to deterministically drive
any mixed state to a spin coherent state for network initialization.


title: On the predictivity of the non-renormalizable quantum field theories

abstract:
  Following a Four Dimensional Renormalization approach to ultraviolet
divergences (FDR), we extend the concept of predictivity to non-renormalizable
quantum field theories at arbitrarily large perturbative orders. The idea of
topological renormalization is introduced, which keeps a finite value for the
parameters of the theory by trading the usual order-by-order renormalization
procedure for an order-by-order redefinition of the perturbative vacuum. One
additional measurement is then sufficient to systematically compute quantum
corrections at any loop order, with no need of absorbing ultraviolet infinities
in the Lagrangian.


title: Gr\"obner bases for (all) Grassmann manifolds

abstract:
  Grassmann manifolds $G_{k,n}$ are among the central objects in geometry and
topology. The Borel picture of the mod 2 cohomology of $G_{k,n}$ is given as a
polynomial algebra modulo a certain ideal $I_{k,n}$. The purpose of this paper
is to understand this cohomology via Gr\"obner bases. Reduced Gr\"obner bases
for the ideals $I_{k,n}$ are determined. An application of these bases is given
by proving an immersion theorem for Grassmann manifolds $G_{5,n}$, which
establishes new immersions for an infinite family of these manifolds.


title:
A convergent blind deconvolution method for post-adaptive-optics
  astronomical imaging

abstract:
  In this paper we propose a blind deconvolution method which applies to data
perturbed by Poisson noise. The objective function is a generalized
Kullback-Leibler divergence, depending on both the unknown object and unknown
point spread function (PSF), without the addition of regularization terms;
constrained minimization, with suitable convex constraints on both unknowns, is
considered. The problem is nonconvex and we propose to solve it by means of an
inexact alternating minimization method, whose global convergence to stationary
points of the objective function has been recently proved in a general setting.
The method is iterative and each iteration, also called outer iteration,
consists of alternating an update of the object and the PSF by means of fixed
numbers of iterations, also called inner iterations, of the scaled gradient
projection (SGP) method. The use of SGP has two advantages: first, it allows to
prove global convergence of the blind method; secondly, it allows the
introduction of different constraints on the object and the PSF. The specific
constraint on the PSF, besides non-negativity and normalization, is an upper
bound derived from the so-called Strehl ratio, which is the ratio between the
peak value of an aberrated versus a perfect wavefront. Therefore a typical
application is the imaging of modern telescopes equipped with adaptive optics
systems for partial correction of the aberrations due to atmospheric
turbulence. In the paper we describe the algorithm and we recall the results
leading to its convergence. Moreover we illustrate its effectiveness by means
of numerical experiments whose results indicate that the method, pushed to
convergence, is very promising in the reconstruction of non-dense stellar
clusters. The case of more complex astronomical targets is also considered, but
in this case regularization by early stopping of the outer iterations is
required.


title: Optical vortex generation from molecular chromophore arrays

abstract:
  The generation of light endowed with orbital angular momentum, frequently
termed optical vortex light, is commonly achieved by passing a conventional
beam through suitably constructed optical elements. This Letter shows that the
necessary phase structure for vortex propagation can be directly produced
through the creation of twisted light from the vacuum. The mechanism is based
on optical emission from a family of chromophore nano-arrays that satisfy
specific geometric and symmetry constraints. Each such array can support pairs
of electronically delocalized doubly degenerate excitons whose azimuthal phase
progression is responsible for the helical wave-front of the emitted radiation.
The exciton symmetry dictates the maximum magnitude of topological charge;
detailed analysis secures the conditions necessary to deliver optical vortices
of arbitrary topological charge.


title: Testing Hypotheses by Regularized Maximum Mean Discrepancy

abstract:
  Do two data samples come from different distributions? Recent studies of this
fundamental problem focused on embedding probability distributions into
sufficiently rich characteristic Reproducing Kernel Hilbert Spaces (RKHSs), to
compare distributions by the distance between their embeddings. We show that
Regularized Maximum Mean Discrepancy (RMMD), our novel measure for kernel-based
hypothesis testing, yields substantial improvements even when sample sizes are
small, and excels at hypothesis tests involving multiple comparisons with power
control. We derive asymptotic distributions under the null and alternative
hypotheses, and assess power control. Outstanding results are obtained on:
challenging EEG data, MNIST, the Berkley Covertype, and the Flare-Solar
dataset.


title:
{\em Herschel}-ATLAS/GAMA: The Environmental Density of Far-Infrared
  Bright Galaxies at $z \leq 0.5$

abstract:
  We compare the environmental and star formation properties of far-infrared
detected and non--far-infrared detected galaxies out to $z \sim0.5$. Using
optical spectroscopy and photometry from the Galaxy And Mass Assembly (GAMA)
and Sloan Digital Sky Survey (SDSS), with far-infrared observations from the
{\em Herschel}-ATLAS Science Demonstration Phase (SDP), we apply the technique
of Voronoi Tessellations to analyse the environmental densities of individual
galaxies. Applying statistical analyses to colour, $r-$band magnitude and
redshift-matched samples, we show there to be a significant difference at the
3.5$\sigma$ level between the normalized environmental densities of these two
populations. This is such that infrared emission (a tracer of star formation
activity) favours underdense regions compared to those inhabited by exclusively
optically observed galaxies selected to be of the same $r-$band magnitude,
colour and redshift. Thus more highly star-forming galaxies are found to reside
in the most underdense environments, confirming previous studies that have
proposed such a correlation. However, the degeneracy between redshift and
far-infrared luminosity in our flux-density limited sample means that we are
unable to make a stronger statement in this respect. We then apply our method
to synthetic light cones generated from semi-analytic models, finding that over
the whole redshift distribution the same correlations between star-formation
rate and environmental density are found.


title:
Solitary modes in nonlocal media with inhomogeneous self-repulsive
  nonlinearity

abstract:
  We demonstrate the existence of two species of stable bright solitons,
fundamental and dipole ones, in one-dimensional self-defocusing nonlocal media,
with the local value of nonlinearity coefficient having one or several minima
and growing at any rate faster than |x| at large values of coordinate x. The
model can be derived for a slab optical waveguide with thermal nonlinearity.
The most essential difference from the local counterpart of this system is the
competition between two different spatial scales, the one determining the
modulation pattern of the nonlinearity coefficient, and the correlation length
of the nonlocality. The competition is explicitly exhibited by analytically
obtained asymptotic form of generic solutions. Particular exact solutions are
found analytically, and full soliton families are constructed in a numerical
form. The multi-channel settings, with two or three local minima of the
nonlinearity coefficient, are considered here for the first time, for both
local and nonlocal models of the present type. States with multiple solitons
launched into different channels are stable if the spacing between them exceeds
a certain minimum value. A regime of stable Josephson oscillations of solitons
between parallel channels is reported too.


title:
Nonlinear absorption of ultrapower laser radiation by relativistic
  underdense plasma

abstract:
  The nonlinear absorption of laser radiation of relativistic intensities in
the underdense plasma by a mechanism of stimulated bremsstrahlung of electrons
on the ions/nuclei is investigated in the low frequency approximation.
Coefficient of nonlinear inverse-bremsstrahlung absorption is studied for
relativistic Maxwellian plasma at asymptotically large values of laser fields
and high temperatures of electrons.


title: The Propagation of Photons in the Dilute Ionized Gas

abstract:
  The dilute ionized gas is very popular in the Universe. Usually only the
Compton interactions, the "Sunyaev-Zel'dovich" effect, were considered while
photons propagated in this medium. In this paper the "soft-photon process" is
considered. Due to the soft photons emitted during the propagation of a photon
in the dilute ionized gas, the main photon (propagating in the original
direction) will be redshifted. The formula to calculate this redshift is
derived.


title: Morse Homotopy and Homological Conformal Field Theory

abstract:
  By studying spaces of flow graphs in a closed oriented manifold, we construct
operations on its cohomology, parametrized by the homology of the moduli spaces
of compact Riemann surfaces with boundary marked points. We show that the
operations satisfy the gluing axiom of an open homological conformal field
theory. This complements previous constructions due to R. Cohen et al., K.
Costello and M. Kontsevich and is also the Morse theoretic counterpart to a
conjectural construction of operations on the Lagrangian Floer homology of the
zero section of a cotangent bundle, obtained by studying uncompactified moduli
spaces of higher genus pseudoholomorphic curves.


title:
Regular sequences and local cohomology modules with respect to a pair of
  ideals

abstract:
  Let $R$ be a Noetherian ring, $I$ and $J$ two ideals of $R$ and $t$ an
integer. Let $S$ be the class of Artinian $R$-modules, or the class of all
$R$-modules $N$ with $\dim_RN\leq k$, where $k$ is an integer. It is proved
that $\inf\{i: H^{i}_{I,J}(M)\notin S\}=\inf\{S-\depth_\frak{a}(M): \frak{a}\in
\tilde{\rm W}(I,J)\}$, where $M$ is a finitely generated $R$-module, or is a
$ZD$-module such that $M/\frak{a}M\notin S$ for all $\frak{a}\in \tilde{\rm
W}(I,J)$. Let $\Supp_R H^{i}_{I,J}(M)$ be a finite subset of $\Max(R)$ for all
$i<t$. It is shown that there are maximal ideals $\frak m_1, \frak
m_2,\ldots,\frak m_k$ of $R$ such that $H^{i}_{I,J}(M)\cong H^{i}_{\frak
m_1}(M)\oplus H^{i}_{\frak m_2}(M)\oplus\cdots\oplus H^{i}_{\frak m_k}(M)$ for
all $i<t$.


title:
INTEGRAL and XMM-Newton observations of IGR J16418-4532: evidence of
  accretion regime transitions in a supergiant fast X-ray transient

abstract:
  We report on combined INTEGRAL and XMM-Newton observations of the supergiant
fast X-ray transient IGR J16418-4532. The observations targeted the X-ray
eclipse region of IGR J16418-4532s orbit with continuous INTEGRAL observations
across ~25% of orbital phase and two quasi-simultaneous XMM-Newton observations
of length 20ks and 14ks, occurring during and just after the eclipse
respectively. An enhanced INTEGRAL emission history is provided with 19
previously unreported outbursts identified in the archival 18-60 keV data set.
The XMM-Newton eclipse observation showed prominent Fe-emission and a flux of
2.8*10^-13 erg cm^-2 s^-1 (0.5 - 10 keV). Through the comparison of the
detected eclipse and post eclipse flux, the supergiant mass loss rate through
the stellar wind was determined as \dot{M}_{w} = 2.3-3.8*10^-7 M_{\odot} yr^-1.
The post eclipse XMM-Newton observation showed a dynamic flux evolution with
signatures of the X-ray pulsation, a period of flaring activity, structured nH
variations and the first ever detection of an X-ray intensity dip, or
'off-state', in a pulsating supergiant fast X-ray transient. Consideration is
given to the origin of the X-ray dip and we conclude that the most applicable
of the current theories of X-ray dip generation is that of a transition between
Compton cooling dominated and radiative cooling dominated subsonic accretion
regimes within the 'quasi-spherical' model of wind accretion. Under this
interpretation, which requires additional confirmation, the neutron star in IGR
J16418-4532 possesses a magnetic field of ~10^14 G, providing tentative
observational evidence of a highly magnetised neutron star in a supergiant fast
X-ray transient for the first time. The implications of these results on the
nature of IGR J16418-4532 itself and the wider SFXT class are discussed.


title: On extra zeros of p-adic L-functions: the crystalline case

abstract:
  We formulate a conjecture about extra zeros of p-adic L-functions at near
central points which generalises the conjecture formulated in our previous
paper. We prove that this conjecture is compatible with Perrin-Riou's theory of
p-adic L-functions.


title: Symmetries and gravitational Chern-Simons Lagrangian terms

abstract:
  We consider some general consequences of adding pure gravitational
Chern-Simons term to manifestly diff-covariant theories of gravity. Extending
the result of a previous paper we enlarge the class of metrics for which the
inclusion of a gCS term in the action does not affect solutions and
corresponding physical quantities. In the case in which such solutions describe
black holes (of general horizon topology) we show that the black hole entropy
is also unchanged. We arrive at these conclusions by proving three general
theorems and studying their consequences. One of the theorems states that the
contribution of the gravitational Chern-Simons to the black hole entropy is
invariant under local rescaling of the metric.


title: TREEWIDTH and PATHWIDTH parameterized by vertex cover

abstract:
  After the number of vertices, Vertex Cover is the largest of the classical
graph parameters and has more and more frequently been used as a separate
parameter in parameterized problems, including problems that are not directly
related to the Vertex Cover. Here we consider the TREEWIDTH and PATHWIDTH
problems parameterized by k, the size of a minimum vertex cover of the input
graph. We show that the PATHWIDTH and TREEWIDTH can be computed in O*(3^k)
time. This complements recent polynomial kernel results for TREEWIDTH and
PATHWIDTH parameterized by the Vertex Cover.


title:
An $S$-adic characterization of minimal subshifts with first difference
  of complexity $1 \leq p(n+1) - p(n) \leq 2$

abstract:
  In [Ergodic Theory Dynam. System, 16 (1996) 663--682], S. Ferenczi proved
that any minimal subshift with first difference of complexity bounded by 2 is
$S$-adic with $\card S \leq 3^{27}$. In this paper, we improve this result by
giving an $S$-adic charaterization of these subshifts with a set $S$ of 5
morphisms, solving by this way the $S$-adic conjecture for this particular
case.


title: The role of twitter in the life cycle of a scientific publication

abstract:
  Twitter is a micro-blogging social media platform for short messages that can
have a long-term impact on how scientists create and publish ideas. We
investigate the usefulness of twitter in the development and distribution of
scientific knowledge. At the start of the life cycle of a scientific
publication, twitter provides a large virtual department of colleagues that can
help to rapidly generate, share and refine new ideas. As ideas become
manuscripts, twitter can be used as an informal arena for the pre-review of
works in progress. Finally, tweeting published findings can communicate
research to a broad audience of other researchers, decision makers, journalists
and the general public that can amplify the scientific and social impact of
publications. However, there are limitations, largely surrounding issues of
intellectual property and ownership, inclusiveness and misrepresentations of
science sound bites. Nevertheless, we believe twitter is a useful social media
tool that can provide a valuable contribution to scientific publishing in the
21st century.


title: Multivariate high-frequency financial data via semi-Markov processes

abstract:
  In this paper we propose a bivariate generalization of a weighted indexed
semi-Markov chains to study the high frequency price dynamics of traded stocks.
We assume that financial returns are described by a weighted indexed
semi-Markov chain model. We show, through Monte Carlo simulations, that the
model is able to reproduce important stylized facts of financial time series
like the persistence of volatility and at the same time it can reproduce the
correlation between stocks. The model is applied to data from Italian stock
market from 1 January 2007 until the end of December 2010.


title:
Water in a Polymeric Electrolyte Membrane: Sorption/Desorption and
  Freezing phenomena

abstract:
  Nafion is a perfluorosulfonated polymer, widely used in Proton Exchange
Membrane Fuel Cells. This polymer adopts a complex structural organisation
resulting from the microsegregation between hydrophobic backbones and
hydrophilic sulfonic acid groups. Upon hydration appear water-filled channels
and cavities, in which are released the acidic protons to form a solution of
hydronium ions in water embedded in the polymer matrix. Below 273 K, a
phenomenon of water sorption/desorption occurs, whose origin is still an open
question. Performing neutron diffraction, we monitored the quantity of ice
formed during the sorption/desorption as a function of temperature down to 180
K. Upon cooling, we observe that ice forms outside of the membrane and
crystallises in the hexagonal Ih form. Simultaneously, the membrane shrinks and
dehydrate, leading to an increase of the hydronium ions concentration inside
the matrix. Reversibly, the ice melts and the membrane re-hydrate upon heating.
A model of solution, whose freezing point varies with the hydronium
concentration, is proposed to calculate the quantity of ice formed as a
function of temperature. The quantitative agreement between the model and
experimental data explains the smooth and reversible behavior observed during
the sorption or desorption of water, pointing out the origin of the phenomena.
The proposed picture reconciles both confinement and entropic effects. Other
examples of water filled electrolyte nano-structures are eventually discussed,
in the context of clarifying the conditions for water transport at low
temperature.


title: Efficient routing on multilayered communication networks

abstract:
  We study the optimal routing on multilayered communication networks, which
are composed of two layers of subnetworks. One is a wireless network, and the
other is a wired network. We develop a simple recurrent algorithm to find an
optimal routing on this kind of multilayered network, where the single-channel
transmission mode and the multichannel transmission mode used on the wireless
subnetwork are considered, respectively. Compared with the performance of the
shortest path algorithm, our algorithm can significantly enhance the transport
capacity. We show that our methods proposed in this letter could take advantage
of the coupling of the two layers to the most extent, so that the wireless
subnetwork could sufficiently utilize the wired subnetwork for transportation.


title:
A detailed study of the modulation of the optical light from Sk160/SMC
  X-1

abstract:
  Eight years of optical photometry from OGLE-III are presented of the optical
counterpart to the High Mass X-ray Binary system, SMC X-1. The optical data
provide the best view to date of the modulation of the light from the system at
the binary period of 3.9d. In addition, it is shown for the first time that the
light is also modulated at the superorbital period - a period associated with
the precessing of a warped accretion disk around the neutron star partner. The
implications for the sources of the various components of the optical light in
this system are discussed.


title: The Ricci flow on generalized Wallach spaces

abstract:
  We consider the asymptotic behavior of the normalized Ricci flow on
generalized Wallach spaces that could be considered as special planar dynamical
systems. All non symmetric generalized Wallach spaces can be naturally
parametrized by three positive numbers $a_1, a_2, a_3$. Our interest is to
determine the type of singularity of all singular points of the normalized
Ricci flow on all such spaces. Our main result gives a qualitative answer for
almost all points $(a_1,a_2,a_3)$ in the cube $(0,1/2]\times (0,1/2]\times
(0,1/2]$.


title: Local Nash Realizations

abstract:
  In this paper we investigate realization theory of a class of non-linear
systems, called Nash systems. Nash systems are non-linear systems whose vector
fields and readout maps are analytic semi-algebraic functions. In this paper we
will present a characterization of minimality in terms of observability and
reachability and show that minimal Nash systems are isomorphic. The results are
local in nature, i.e. they hold only for small time intervals. The hope is that
the presented results can be extended to hold globally.


title:
Properties of para-terphenyl as detector for alpha, beta and gamma
  radiation

abstract:
  Organic scintillators are often chosen as radiation detectors for their fast
decay time and their low Z, while inorganic ones are used when high light ields
are required. In this paper we show that a para-terphenyl based detector has a
blend of properties of the two categories that can be optimal for energy and
position measurements of low energy charged particles. On 0.1%
diphenylbutadiene doped para-terphenyl samples we measure a light yield
3.5+-0.2 times larger than a typical organic scintillator (EJ-200), and a
rejection power for 660 keV photons, with respect to electrons of the same
energy, ranging between 3-11%, depending on the signal threshold. We also
measure a light attenuation length = 4.73+-0.06 mm and we demonstrate that,
with the measurements performed in this paper, a simulation based on FLUKA can
properly reproduce the measured spectra.


title: Free Fermions on causal sets

abstract:
  We construct a Dirac theory on causal sets; a key element in the construction
being that the causet must be regarded as emergent in an appropriate sense too.
We further notice that mixed norm spaces appear in the construction allowing
for negative norm particles and "ghosts".


title:
Quantum atom-light interfaces in the gaussian description for spin-1
  systems

abstract:
  We extend the covariance-matrix description of atom--light quantum
interfaces, originally developed for real and effective spin-1/2 atoms, to
include "spin alignment" degrees of freedom. This allows accurate modeling of
optically-probed spin-1 ensembles in arbitrary magnetic fields. We also include
technical noise terms that are very common in experimental situations. These
include magnetic field noise, variable atom number and the effect of magnetic
field inhomogeneities. We demonstrate the validity of our extended model by
comparing numerical simulations to a free--induction decay (FID) measurement of
polarized $^{87}$Rb atoms in the $f = 1$ ground state. We qualitatively and
quantitatively reproduce experimental results with all free parameters of the
simulations fixed. The model can be easily extended to larger spin systems, and
adapted to more complicated experimental situations.


title: Deep Learning of Representations: Looking Forward

abstract:
  Deep learning research aims at discovering learning algorithms that discover
multiple levels of distributed representations, with higher levels representing
more abstract concepts. Although the study of deep learning has already led to
impressive theoretical results, learning algorithms and breakthrough
experiments, several challenges lie ahead. This paper proposes to examine some
of these challenges, centering on the questions of scaling deep learning
algorithms to much larger models and datasets, reducing optimization
difficulties due to ill-conditioning or local minima, designing more efficient
and powerful inference and sampling procedures, and learning to disentangle the
factors of variation underlying the observed data. It also proposes a few
forward-looking research directions aimed at overcoming these challenges.


title: The importance of being discrete in sex

abstract:
  The puzzle associated with the cost of sex, an old problem of evolutionary
biology, is discussed here from the point of view of nonequilibrium statistical
mechanics. The results suggest, in a simplified model, that the prevalence of
sexual species in nature can be a natural and necessary consequence of the
discrete character of the nonlinear interactions between couples and their
pathogens/parasites. Mapped into a field theory, the stochastic processes
performed by the species are described by continuous fields in space and time.
The way that the model's parameters scale with subsequent iterations of the
renormalization group gives us information about the stationary emergent
properties of the complex interacting systems modeled. We see that the
combination of one aspect of the Red Queen theory with the stochastic processes
theory, including spatiotemporal interactions, provides interesting insights
into this old Darwinian dilemma.


title:
PEACE: Pulsar Evaluation Algorithm for Candidate Extraction -- A
  software package for post-analysis processing of pulsar survey candidates

abstract:
  Modern radio pulsar surveys produce a large volume of prospective candidates,
the majority of which are polluted by human-created radio frequency
interference or other forms of noise. Typically, large numbers of candidates
need to be visually inspected in order to determine if they are real pulsars.
This process can be labor intensive. In this paper, we introduce an algorithm
called PEACE (Pulsar Evaluation Algorithm for Candidate Extraction) which
improves the efficiency of identifying pulsar signals. The algorithm ranks the
candidates based on a score function. Unlike popular machine-learning based
algorithms, no prior training data sets are required. This algorithm has been
applied to data from several large-scale radio pulsar surveys. Using the
human-based ranking results generated by students in the Arecibo Remote Command
enter programme, the statistical performance of PEACE was evaluated. It was
found that PEACE ranked 68% of the student-identified pulsars within the top
0.17% of sorted candidates, 95% within the top 0.34%, and 100% within the top
3.7%. This clearly demonstrates that PEACE significantly increases the pulsar
identification rate by a factor of about 50 to 1000. To date, PEACE has been
directly responsible for the discovery of 47 new pulsars, 5 of which are
millisecond pulsars that may be useful for pulsar timing based
gravitational-wave detection projects.


title:
A Fast Search Algorithm for <m,m,m> Triple Product Property Triples and
  an Application for 5x5 Matrix Multiplication

abstract:
  We present a new fast search algorithm for <m,m,m> Triple Product Property
(TPP) triples as defined by Cohn and Umans in 2003. The new algorithm achieves
a speed-up factor of 40 up to 194 in comparison to the best known search
algorithm. With a parallelized version of the new algorithm we are able to
search for TPP triples in groups up to order 55.
  As an application we identify a list of groups that would realize 5x5 matrix
multiplication with under 100 resp. 125 scalar multiplications (the best known
upper bound by Makarov 1987 resp. the trivial upper bound) if they contain a
<5,5,5> TPP triple. With our new algorithm we show that no group can realize
5x5 matrix multiplication better than Makarov's algorithm.


title:
TNOs are Cool: A survey of the trans-Neptunian region. VIII. Combined
  Herschel PACS and SPIRE observations of 9 bright targets at 70--500 micron

abstract:
  Transneptunian objects (TNOs) are bodies populating the Kuiper Belt and they
are believed to retain the most pristine and least altered material of the
solar system. The Herschel Open Time Key Program entitled "TNOs are Cool: A
survey of the trans-Neptunian region" has been awarded 373 h to investigate the
albedo, size distribution and thermal properties of TNOs and Centaurs. Here we
focus on the brightest targets observed by both the PACS and SPIRE multiband
photometers: the dwarf planet Haumea, six TNOs (Huya, Orcus, Quaoar, Salacia,
2002 UX25, and 2002 TC302), and two Centaurs (Chiron and Chariklo). Flux
densities are derived from PACS and SPIRE instruments using optimised data
reduction methods. The spectral energy distribution obtained with the Herschel
PACS and SPIRE instruments over 6 bands (centred at 70, 100, 160, 250, 350, and
500 $\mu$m), and with Spitzer-MIPS at 23.7 and 71.4 $\mu$m has been modelled
with the NEATM thermal model in order to derive the albedo, diameter, and
beaming factor. For the Centaurs Chiron and Chariklo and for the 1000 km sized
Orcus and Quaoar, a thermophysical model was also run to better constrain their
thermal properties. We derive the size, albedo, and thermal properties,
including thermal inertia and surface emissivity, for the 9 TNOs and Centaurs.
Several targets show a significant decrease in their spectral emissivity
longwards of $\sim$300 $\mu$m and especially at 500 $\mu$m. Using our size
estimations and the mass values available in the literature, we also derive the
bulk densities for the binaries Quaoar/Weywot (2.18$^{+0.43}_{-0.36}$
g/cm$^3$), Orcus/Vanth (1.53$^{+0.15}_{-0.13}$ g/cm$^3$), and Salacia/Actea
(1.29$^{+0.29}_{-0.23}$ g/cm$^3$). Quaoar's density is similar to that of the
other dwarf planets Pluto and Haumea, and its value implies high contents of
refractory materials mixed with ices.


title: Affine walled Brauer algebras

abstract:
  A new class of associative algebras referred to as affine walled Brauer
algebras are introduced. These algebras are free with infinite rank over a
commutative ring containing 1. Then level two walled Brauer algebras over C are
defined, which are some cyclotomic quotients of affine walled Brauer algebras.
We establish a super Schur-Weyl duality between affine walled Brauer algebras
and general linear Lie superalgebras, and realize level two walled Brauer
algebras as endomorphism algebras of tensor modules of Kac modules with mixed
tensor products of the natural module and its dual over general linear Lie
superalgebras, under some conditions. We also prove the weakly cellularity of
level two walled Brauer algebras, and give a classification of their
irreducible modules over C. This in tur enables us to classify the
indecomposable direct summands of the said tensor modules.


title: Final-State Interactions in the Process pp -> pKLambda

abstract:
  The possibility to determine the pLambda scattering length from the
final-state interaction in the reaction pp->pKLambda is investigated
experimentally. From a transversely polarized measurement, the K analyzing
power (A_N) which, in principle, allows one to extract the spin triplet
scattering length is studied. An unexpected energy dependence of the
forward/backward symmetric part of A_N is found. The influence of N*-resonances
on the pLambda invariant mass spectrum is investigated by exploiting the large
acceptance for the process pp->pKLambda->pKppi and is found to be the main
source of uncertainty for determining the pLambda scattering length.


title:
Difference integrability conditions for parameterized linear difference
  and differential equations

abstract:
  This paper is devoted to integrability conditions for systems of linear
difference and differential equations with difference parameters. It is shown
that such a system is difference isomonodromic if and only if it is difference
isomonodromic with respect to each parameter separately. Due to this result, it
is no longer necessary to solve non-linear difference equations to verify
isomonodromicity, which will improve efficiency of computation with these
systems.


title: Complexity Theory for Operators in Analysis

abstract:
  We propose an extension of the framework for discussing the computational
complexity of problems involving uncountably many objects, such as real
numbers, sets and functions, that can be represented only through
approximation. The key idea is to use (a certain class of) string functions as
names representing these objects. These are more expressive than infinite
sequences, which served as names in prior work that formulated complexity in
more restricted settings. An advantage of using string functions is that we can
define their "size" in the way inspired by higher-type complexity theory. This
enables us to talk about computation on string functions whose time or space is
bounded polynomially in the input size, giving rise to more general analogues
of the classes P, NP, and PSPACE. We also define NP- and PSPACE-completeness
under suitable many-one reductions.
  Because our framework separates machine computation and semantics, it can be
applied to problems on sets of interest in analysis once we specify a suitable
representation (encoding). As prototype applications, we consider the
complexity of functions (operators) on real numbers, real sets, and real
functions. For example, the task of numerical algorithms for solving a certain
class of differential equations is naturally viewed as an operator taking real
functions to real functions. As there was no complexity theory for operators,
previous results only stated how complex the solution can be. We now
reformulate them and show that the operator itself is polynomial-space
complete.


title: Martingales on manifolds with time-dependent connection

abstract:
  We define martingales on manifolds with time-dependent connection, extending
in this way the theory of stochastic processes on manifolds with time-changing
geometry initiated by Arnaudon, Coulibaly and Thalmaier (2008). We show that
some, but not all properties of martingales on manifolds with a fixed
connection extend to this more general setting.


title: The Gromov-Lawson-Rosenberg conjecture for some finite groups

abstract:
  The Gromov-Lawson-Rosenberg conjecture for a group G states that a compact
spin manifold with fundamental group G admits a metric of positive scalar
curvature if and only if a certain topological obstruction vanishes. It is
known to be true for G=1, if G has periodic cohomology, and if G is a free
group, free abelian group, or the fundamental group of an orientable surface.
It is also known to be false for a large class of infinite groups. However,
there are no known counterexamples for finite groups. In this dissertation we
will give a general outline of the positive scalar curvature problem, and
sketch proofs of some of the known positive and negative results. We will then
focus on finite groups, and proceed to prove the conjecture for the Klein
4-group, all dihedral groups (joint with Michael Joachim), the semi-dihedral
group of order 16 (joint with Kijti Rodtes), and the rank three group (Z/2)^3.
The topological obstruction in question lies in the connective real homology
ko_*(BG) of the classifying space of BG. Our method of proof is to first sketch
calculations of ko_*(BG), using the techniques and calculations of Bruner and
Greenlees. We then give explicit geometric constructions to produce
sufficiently many manifolds of positive scalar curvature.


title: Non-Baryonic Dark Matter in Cosmology

abstract:
  This paper is a broad-band review of the current status of non-baryonic dark
matter research. I start with a historical overview of the evidences of dark
matter existence, then I discuss how dark matter is distributed from small
scale to large scale, and I then verge the attention to dark matter nature:
dark matter candidates and their detection. I finally discuss some of the
limits of the $\Lambda$CDM model, with particular emphasis on the small scale
problems of the paradigm.


title:
Cauchy theory for the gravity water waves system with non localized
  initial data

abstract:
  In this article, we develop the local Cauchy theory for the gravity water
waves system, for rough initial data which do not decay at infinity. We work in
the context of $L^2$-based uniformly local Sobolev spaces introduced by Kato.
We prove a classical well-posedness result (without loss of derivatives). Our
result implies also a local well-posedness result in H\"older spaces (with loss
of $d/2$ derivatives). As an illustration, we solve a question raised by
Boussinesq on the water waves problem in a canal. We take benefit of an
elementary observation to show that the strategy suggested by Boussinesq does
indeed apply to this setting.


title: From the Grid to the Smart Grid, Topologically

abstract:
  The Smart Grid is not just about the digitalization of the Power Grid. In its
more visionary acceptation, it is a model of energy management in which the
users are engaged in producing energy as well as consuming it, while having
information systems fully aware of the energy demand-response of the network
and of dynamically varying prices. A natural question is then: to make the
Smart Grid a reality will the Distribution Grid have to be updated? We assume a
positive answer to the question and we consider the lower layers of Medium and
Low Voltage to be the most affected by the change. In our previous work, we
have analyzed samples of the Dutch Distribution Grid in our previous work and
we have considered possible evolutions of these using synthetic topologies
modeled after studies of complex systems in other technological domains in
another previous work. In this paper, we take an extra important further step
by defining a methodology for evolving any existing physical Power Grid to a
good Smart Grid model thus laying the foundations for a decision support system
for utilities and governmental organizations. In doing so, we consider several
possible evolution strategies and apply then to the Dutch Distribution Grid. We
show how more connectivity is beneficial in realizing more efficient and
reliable networks. Our proposal is topological in nature, and enhanced with
economic considerations of the costs of such evolutions in terms of cabling
expenses and economic benefits of evolving the Grid.


title:
The supergiant B[e] star LHA 115-S 18 - binary and/or luminous blue
  variable?

abstract:
  The mechanism by which supergiant (sg)B[e] stars support cool, dense dusty
discs/tori and their physical relationship with other evolved, massive stars
such as luminous blue variables is uncertain. In order to investigate both
issues we have analysed the long term behaviour of the canonical sgB[e] star
LHA 115-S 18. We employed the OGLE II-IV lightcurve to search for (a-)periodic
variability and supplemented these data with new and historic spectroscopy. In
contrast to historical expectations for sgB[e] stars, S18 is both
photometrically and spectroscopically highly variable. The lightcurve is
characterised by rapid aperiodic `flaring' throughout the 16 years of
observations. Changes in the high excitation emission line component of the
spectrum imply evolution in the stellar temperature - as expected for luminous
blue variables - although somewhat surprisingly, spectroscopic and photometric
variability appears not to be correlated. Characterised by emission in low
excitation metallic species, the cool circumstellar torus appears largely
unaffected by this behaviour. Finally, in conjunction with intense, highly
variable HeII emission, X-ray emission implies the presence of an unseen binary
companion. S18 provides observational support for the putative physical
association of (a subset of) sgB[e] stars and luminous blue variables. Given
the nature of the circumstellar environment of S18 and that luminous blue
variables have been suggested as SN progenitors, it is tempting to draw a
parallel to the progenitors of SN1987A and the unusual transient SN2009ip.
Moreover the likely binary nature of S18 strengthens the possibility that the
dusty discs/tori that characterise sgB[e] stars are the result of binary-driven
mass-loss; consequently such stars may provide a window on the short lived
phase of mass-transfer in massive compact binaries.


title:
The maximal length of the period of a periodic word defined by
  restrictions

abstract:
  We determine the maximal length of the period of a periodic word defined by
$n$ restrictions. It happens to be the corresponding Fibonacci number.


title:
The Dirac Quantum Cellular Automaton in one dimension: Zitterbewegung
  and scattering from potential

abstract:
  We study the dynamical behaviour of the quantum cellular automaton of Refs.
[1, 2], which reproduces the Dirac dynamics in the limit of small wavevectors
and masses. We present analytical evaluations along with computer simulations,
showing how the automaton exhibits typical Dirac dynamical features, as the
Zitterbewegung and the scattering behaviour from potential that gives rise to
the so-called Klein paradox. The motivation is to show concretely how pure
processing of quantum information can lead to particle mechanics as an emergent
feature, an issue that has been the focus of solid-state, optical and
atomic-physics quantum simulator.


title:
Lattice computation of $B \to D^*,\;D^{**}\ell \nu$ form factors at
  finite heavy masses

abstract:
  We propose a strategy to compute form factors entering the semileptonic decay
channel of $B$ mesons into orbitally excited (P wave) $D^{**}$ charmed mesons
on the lattice using, for the first time, realistic charm quarks having a
finite mass. We present preliminary results about the extracted transition
amplitudes and form factors at different recoils and at three different $b$
quark masses.


title:
An entropy formula for the heat equation on manifolds with
  time-dependent metric, application to ancient solutions

abstract:
  We introduce a new entropy functional for nonnegative solutions of the heat
equation on a manifold with time-dependent Riemannian metric. Under certain
integral assumptions, we show that this entropy is non-decreasing, and moreover
convex if the metric evolves under super Ricci flow (which includes Ricci flow
and fixed metrics with nonnegative Ricci curvature). As applications, we
classify nonnegative ancient solutions to the heat equation according to their
entropies. In particular, we show that a nonnegative ancient solution whose
entropy grows sublinearly on a manifold evolving under super Ricci flow must be
constant. The assumption is sharp in the sense that there do exist nonconstant
positive eternal solutions whose entropies grow exactly linearly in time. Some
other results are also obtained.