title:
New explicit-in-dimension estimates for the cardinality of
  high-dimensional hyperbolic crosses and approximation of functions having
  mixed smoothness

abstract:
  We are aiming at sharp and explicit-in-dimension estimations of the
cardinality of $s$-dimensional hyperbolic crosses where $s$ may be large, and
applications in high-dimensional approximations of functions having mixed
smoothness. In particular, we provide new tight and explicit-in-dimension upper
and lower bounds for the cardinality of hyperbolic crosses. We apply them to
obtain explicit upper and lower bounds for Kolmogorov $N$-widths and
$\varepsilon$-dimensions of a modified Korobov class parametrized by positive
$a$ of $s$-variate periodic functions having mixed smoothness $r$, as a
function of three variables $N,s,a$ and $\varepsilon, s,a$, respectively, when
$N,s$ may be large, $\varepsilon$ may be small and $a$ may range from 0 to
infinity. Based on these results we describe a complete classification of
tractability for the problem of $\varepsilon$-dimensions of the modified
Korobov class. In particular, we prove the introduced exponential tractability
of this problem for $a>1$. All of these methods and results are also extended
to high-dimensional approximations of non-periodic functions by Jacobi
polynomials with powers in hyperbolic crosses.


title:
Particular solutions to multidimensional PDEs represented in the form of
  one-dimensional flow

abstract:
  We represent an algorithm reducing the $(M+1)$-dimensional nonlinear partial
differential equation (PDE) representable in the form of one-dimensional flow
$u_t + w_{x_1}(u,u_{x},u_{xx},\dots)=0$, (where $w$ is an arbitrary local
function of $u$ and its $x_i$-derivatives, $i=1,\dots,M$) to the family of
$M$-dimensional nonlinear PDEs $F(u,w)=0$, where $F$ is general (or particular)
solution of a certain second order two-dimensional nonlinear PDE. Particularly,
the $M$-dimensional PDE might be an ODE which, in some cases, may be integrated
yielding the explicite solutions to the original ($M+1$)-dimensional PDE.
Moreover, the spectral parameter may be introduced into the function $F$ which
yields a linear spectral equation associated with the original PDE. Simplest
examples of nonlinear PDEs with explicite solutions are given.


title: Augmenting graphs to minimize the diameter

abstract:
  We study the problem of augmenting a weighted graph by inserting edges of
bounded total cost while minimizing the diameter of the augmented graph. Our
main result is an FPT 4-approximation algorithm for the problem.


title: Initial conformation of kinesin's neck linker

abstract:
  How ATP binding initiates the docking process of kinesin's neck linker is a
key question in understanding kinesin mechanism. It is believed that the
formation of an extra turn structure by the first three amino acids of neck
linker (LYS325, THR326, ILE327 in 2KIN) is crucial for initiating the docking
process. But the initial conformation of neck linker (specially the three amino
acids of the extra turn) and the neck linker docking initiation mechanism
remain unclear. By using molecular dynamics method, we investigate the initial
conformation of kinesin's neck linker in the docking process. We find that, in
the initial state of NL docking process, NL still has interactions with
{\beta}0 and forms a conformation similar to the "cover-neck bundle" structure
proposed by Hwang et al. [Structure 2008, 16(1): 62-71]. From this initial
structure, the docking of the "cover-neck bundle" structure can be achieved.
The motor head provides a forward force on the initial cover-neck bundle
structure through ATP-induced rotation. This force, together with the
hydrophobic interaction of ILE327 with the hydrophobic pocket on the motor
head, drives the formation of the extra turn and initiates the neck linker
docking process.


title: Saying What You're Looking For: Linguistics Meets Video Search

abstract:
  We present an approach to searching large video corpora for video clips which
depict a natural-language query in the form of a sentence. This approach uses
compositional semantics to encode subtle meaning that is lost in other systems,
such as the difference between two sentences which have identical words but
entirely different meaning: "The person rode the horse} vs. \emph{The horse
rode the person". Given a video-sentence pair and a natural-language parser,
along with a grammar that describes the space of sentential queries, we produce
a score which indicates how well the video depicts the sentence. We produce
such a score for each video clip in a corpus and return a ranked list of clips.
Furthermore, this approach addresses two fundamental problems simultaneously:
detecting and tracking objects, and recognizing whether those tracks depict the
query. Because both tracking and object detection are unreliable, this uses
knowledge about the intended sentential query to focus the tracker on the
relevant participants and ensures that the resulting tracks are described by
the sentential query. While earlier work was limited to single-word queries
which correspond to either verbs or nouns, we show how one can search for
complex queries which contain multiple phrases, such as prepositional phrases,
and modifiers, such as adverbs. We demonstrate this approach by searching for
141 queries involving people and horses interacting with each other in 10
full-length Hollywood movies.


title:
Arclength parametrized Hamilton's equations for the calculation of
  instantons

abstract:
  A method is presented to compute minimizers (instantons) of action
functionals using arclength parametrization of Hamilton's equations. This
method can be interpreted as a local variant of the geometric minimum action
method (gMAM) introduced to compute minimizers of the Freidlin-Wentzell action
functional that arises in the context of large deviation theory for stochastic
differential equations. The method is particularly well-suited to calculate
expectations dominated by noise-induced excursions from deterministically
stable fixpoints. Its simplicity and computational efficiency are illustrated
here using several examples: a finite-dimensional stochastic dynamical system
(an Ornstein-Uhlenbeck model) and two models based on stochastic partial
differential equations: the $\phi^4$-model and the stochastically driven
Burgers equation.

categories: cond-mat.stat-mech math-ph math.MP physics.comp-ph


title:
Generalizing the correlated chromophore domain model of reversible
  photodegradation to include the effects of an applied electric field

abstract:
  All observations of photodegradation and self healing follow the predictions
of the correlated chromophore domain model. [Ramini et.al. Polym. Chem., 2013,
4, 4948.] In the present work, we generalize the domain model to describe the
effects of an electric field by including induced dipole interactions between
molecules in a domain by means of a self-consistent field approach. This
electric field correction is added to the statistical mechanical model to
calculate the distribution of domains that are central to healing. Also
included in the model are the dynamics due to the formation of an irreversibly
damaged species. As in previous studies, the model with a one-dimensional
domain best explains all experimental data of the population as a function of
time, temperature, intensity, concentration, and now applied electric field.
Though the nature of a domain is yet to be determined, the fact that only
one-dimensional domain models are consistent with observations suggests that
they might be made of correlated dye molecules along polymer chains.


title:
CHx adsorption (x=1-4) and thermodynamic stability on CeO2(111) surface:
  A first-principles investigation

abstract:
  We present an ab initio investigation of the interaction between methane, its
dehydrogenated forms and the cerium oxide surface. In particular, the
stoichiometric CeO2(111) surface and the one with oxygen vacancies are
considered. We study the geometries, energetics and electronic structures of
various configurations of these molecules adsorbed on the surface in vacuum,
and we extend the analysis to realistic environmental conditions. A phase
diagram of the adsorbate-surface system is constructed and relevant transition
phases are analyzed in detail, showing the conditions where partial oxidation
of methane can occur.


title: Edge-signed graphs with smallest eigenvalue greater than -2

abstract:
  We give a structural classification of edge-signed graphs with smallest
eigenvalue greater than -2. We prove a conjecture of Hoffman about the smallest
eigenvalue of the line graph of a tree that was stated in the 1970s.
Furthermore, we prove a more general result extending Hoffman's original
statement to all edge-signed graphs with smallest eigenvalue greater than -2.
Our results give a classification of the special graphs of fat Hoffman graphs
with smallest eigenvalue greater than -3.


title:
Nanodiamonds with silicon vacancy defects for non-toxic photostable
  fluorescent labeling of neural precursor cells

abstract:
  Nanodiamonds (NDs) containing silicon vacancy (SiV) defects were evaluated as
a potential biomarker for the labeling and fluorescent imaging of neural
precursor cells (NPCs). SiV-containing NDs were synthesized using chemical
vapor deposition and silicon ion implantation. Spectrally, SiV-containing NDs
exhibited extremely stable fluorescence and narrow bandwidth emission with an
excellent signal to noise ratio exceeding that of NDs containing
nitrogen-vacancy (NV) centers. NPCs labeled with NDs exhibited normal cell
viability and proliferative properties consistent with biocompatibility. We
conclude that SiVcontaining NDs are a promising biomedical research tool for
cellular labeling and optical imaging in stem cell research.


title: Evolution of Asymmetric Raman line-shape from nano-structures

abstract:
  A step-by-step evolution of an asymmetric Raman line-shape function from a
Lorentzian line-shape is presented here for low dimensional semiconductors. The
evolution reported here is based on the phonon confinement model which is
successfully used in literature to explain the asymmetric Raman line-shape from
semiconductor nano-structures. Physical significance of different terms in the
theoretical asymmetric Raman line-shape has been explained here. Better
understanding of theoretical reasoning behind each term allows one to use the
theoretical Raman line-shape without going into details of theory from first
principle. This will enable one to empirically derive a theoretical Raman
line-shape function for any material if information about its phonon
dispersion, size dependence etc is known.


title: Weil representations and metaplectic groups over an integral domain

abstract:
  Given F a locally compact, non-discrete, non-archimedean field of
characteristic different from 2 and R an integral domain such that a
non-trivial smooth F-character with values in the multiplicative group of R
exists, we construct the (reduced) metaplectic group attached to R. We show
that it is in most cases a double cover of the symplectic group over F. Finally
we define a faithful infinite dimensional R-representation of the metaplectic
group analogue to the Weil representation in the complex case.


title:
Differentiating the stochastic entropy for compact negatively curved
  spaces under conformal changes

abstract:
  We consider the universal cover of a closed Riemannian manifold of negative
sectional curvature. We show that the linear drift and the stochastic entropy
are differentiable under any C^3 one-parameter family of C^3 conformal changes
of the original metric.


title:
Effects of dopants in InOx-based amorphous oxide semiconductors for
  thin-film transistor applications

abstract:
  Amorphous metal oxide thin-film transistors (TFT) are fabricated using
InOx-based semiconductors doped with TiO2, WO3 or SiO2. Although density of
dopant is low in the film, change in the electrical properties showed strong
dependence on the dopant species. We found that the dependence could be
reasonably explained by the bond-dissociation energy. By incorporating the
dopant with higher bond-dissociation energy, the film becomes less sensitive to
oxygen partial pressure used during sputtering deposition and remains
electrically stable to thermal annealing treatment. The concept of
bond-dissociation energy can contribute to the realization of more stable metal
oxide TFTs for flat panel displays.


title: Closing a Gap in the Complexity of Refinement Modal Logic

abstract:
  Refinement Modal Logic (RML), which was recently introduced by Bozzelli et
al., is an extension of classical modal logic which allows one to reason about
a changing model. In this paper we study computational complexity questions
related to this logic, settling a number of open problems. Specifically, we
study the complexity of satisfiability for the existential fragment of RML, a
problem posed by Bozzelli, van Ditmarsch and Pinchinat. Our main result is a
tight PSPACE upper bound for this problem, which we achieve by introducing a
new tableau system. As a direct consequence, we obtain a tight characterization
of the complexity of RML satisfiability for any fixed number of alternations of
refinement quantifiers. Additionally, through a simple reduction we establish
that the model checking problem for RML is PSPACE-complete, even for formulas
with a single quantifier.


title:
Interlayer Diffusion of Nuclear Spin Polarization in $\nu=2/3$ Quantum
  Hall States

abstract:
  At the spin transition point of $\nu=2/3$ quantum Hall states, nuclear spins
in a two-dimensional electron gas are polarized by an electric current. Using
GaAs/AlGaAs double-quantum-well samples, we first observed the spatial
diffusion of nuclear spin polarization between the two layers when the nuclear
spin polarization is current-induced in one layer. By numerical simulation, we
estimated the diffusion constant of the nuclear spin polarization to be $15 \pm
7$\,nm$^2$/s.


title: Magnetism and unusual Cu valency in quadruple perovskites

abstract:
  We study a selection of Cu-containing magnetic quadruple perovskites
(CaCu$_{3}$Ti$_{4}$O$_{12}$, LaCu$_{3}$Fe$_{4}$O$_{12}$, and
YCu$_{3}$Co$_{4}$O$_{12}$) by ab initio calculations, and show that Cu is in an
effective divalent Cu(II)-like state or a trivalent Cu(III) state depending on
the choice of octahedral cation. Based on the electronic structure, we also
discuss the role of Mott and Zhang-Rice physics in this materials class.


title: Pr\"ufer-like conditions on an amalgamated algebra along an ideal

abstract:
  Let $f:A\longrightarrow B$ be a ring homomorphism and let $\mathfrak b$ be an
ideal of $B$. In this paper we study Pr\"ufer like conditions in the
amalgamation of $A$ with $B$ along $\mathfrak b$, with respect to $f$, a ring
construction introduced in 2009 by D'Anna, Finocchiaro and Fontana.


title:
On the theory of Double Quantum NMR in polymer systems: the second
  cumulant approximation for many spin I=1/2 systems

abstract:
  General analytical expressions for Double Quantum Nuclear Magnetic Resonance
(NMR) kinetic curves of many-spin I=1/2 systems are derived with an accuracy of
the second cumulant approximation. The expressions obtained exactly describe
the initial part of the kinetic curves and provide a reasonable approximation
up to times of about twice the effective spin-relaxation time. For the case
when the system contains two isolated spins, this result exactly reproduces
known expressions. In the case of polymer melts, the intermolecular magnetic
dipole-dipole interactions significantly influence the time dependence of the
DQ NMR kinetic curves.


title: On the similarity of Tensors

abstract:
  Let $\mathbb{P}_n$ be the set of all matrices which have the same zero
patterns with some permutation matrix of order $n$.
  In this paper, we prove the following result: Let $\mathbb{I}$ be the unit
tensor of order $m\ge3$ and dimension $n\ge2$. Suppose that $P$ and $Q$ are two
matrices with $P\mathbb{I}Q=\mathbb{I}$, then $P,Q\in \mathbb{P}_n$. This gives
a characterization for the similarities of tensors with order $m\ge3$.


title: Spectral spaces and ultrafilters

abstract:
  Let $X$ be the prime spectrum of a ring. In [arXiv:0707.1525] the authors
define a topology on $X$ by using ultrafilters and they show that this topology
is precisely the constructible topology. In this paper we generalize the
construction given in [arXiv:0707.1525] and, starting from a set $X$ and a
collection of subsets $\mathcal{F}$ of $X$, we define by using ultrafilters a
topology on $X$ in which $\mathcal F$ is a collection of clopen sets. We use
this construction for giving a new characterization of spectral spaces and
several new examples of spectral spaces.


title: Constraining the mass and width of the $N^*(1685)$ resonance

abstract:
  We have examined the existence of the $N^*(1685)$ resonance, which is
recently listed by the Particle Data Group as a one-star nucleon resonance, by
using a covariant isobar model for kaon photoproduction and assuming that the
resonance has $J^p=1/2^+$, in accordance with our previous finding. After the
inclusion of this resonance the changes in the total $\chi^2$ show two clear
minima at $M_{N^*}=1650$ and 1696 MeV, which correspond to two different
resonance states. The former corresponds to the narrow nucleon resonance found
in our previous investigation, whereas the latter corresponds to a new
resonance found as we increase the resonance width. From the latter we derive
the mass and width relation of the $N^*(1685)$ resonance. We observe that the
properties of both the $N^*(1685)$ and $N^*(1710)P_{11}$ resonances are
strongly correlated. Although the best fit of the present work yields
$M_{N^*}=1696$ MeV and $\Gamma_{N^*}=76$ MeV, the apparently small
$N^*(1710)P_{11}$ coupling constant to the $K^+\Lambda$ channel found in
previous investigations suggests that $\Gamma_{N^*}\lesssim 35$ MeV, which,
according to the mass and width relation, corresponds to $M_{N^*}\lesssim 1680$
MeV.


title: A skew Gaussian decomposable graphical model

abstract:
  This paper propose a novel decomposable graphical model to accommodate skew
Gaussian graphical models. We encode conditional independence structure among
the components of the multivariate closed skew normal random vector by means of
a decomposable graph and so that the pattern of zero off-diagonal elements in
the precision matrix corresponds to the missing edges of the given graph. We
present conditions that guarantee the propriety of the posterior distributions
under the standard noninformative priors for mean vector and precision matrix,
and a proper prior for skewness parameter. The identifiability of the
parameters is investigated by a simulation study. Finally, we apply our
methodology to two data sets.


title: On the canonical ideals of one-dimensional Cohen-Macaulay local rings

abstract:
  In this paper we consider the problem of finding explicitly canonical ideals
of one-dimensional Cohen-Macaulay local rings. We show that Gorenstein ideals
contained in a high power of the maximal ideal are canonical ideals. In the
codimension two case, from a Hilbert-Burch resolution, we show how to construct
canonical ideals of curve singularities. Finally, we translate the problem of
the analytic classification of curve singularities to the classification of
local Artin Gorenstein rings with suitable length.


title:
Construction of dynamics and time-ordered exponential for unbounded
  non-symmetric Hamiltonians

abstract:
  We prove under certain assumptions that there exists a solution of the
Schrodinger or the Heisenberg equation of motion generated by a linear operator
H acting in some complex Hilbert space H, which may be unbounded, not
symmetric, or not normal. We also prove that, under the same assumptions, there
exists a time evolution operator in the interaction picture and that the
evolution operator enjoys a useful series expansion formula. This expansion is
considered to be one of the mathematically rigorous realizations of so called
"time-ordered exponential", which is familiar in the physics literature. We
apply the general theory to prove the existence of dynamics for the
mathematical model of Quantum Electrodynamics (QED) quantized in the Lorenz
gauge, the interaction Hamiltonian of which is not even symmetric or normal.


title: Normal Cones and Thompson Metric

abstract:
  The aim of this paper is to study the basic properties of the Thompson metric
$d_T$ in the general case of a real linear space $X$ ordered by a cone $K$. We
show that $d_T$ has monotonicity properties which make it compatible with the
linear structure. We also prove several convexity properties of $d_T$ and some
results concerning the topology of $d_T$, including a brief study of the
$d_T$-convergence of monotone sequences. It is shown most of the results are
true without any assumption of an Archimedean-type property for $K$. One
considers various completeness properties and one studies the relations between
them. Since $d_T$ is defined in the context of a generic ordered linear space,
with no need of an underlying topological structure, one expects to express its
completeness in terms of properties of the ordering, with respect to the linear
structure. This is done in this paper and, to the best of our knowledge, this
has not been done yet. The Thompson metric $d_T$ and order-unit (semi)norms
$|\cdot|_u$ are strongly related and share important properties, as both are
defined in terms of the ordered linear structure. Although $d_T$ and
$|\cdot|_u$ are only topological (and not metrical) equivalent on $K_u$, we
prove that the completeness is a common feature. One proves the completeness of
the Thompson metric on a sequentially complete normal cone in a locally convex
space. At the end of the paper, it is shown that, in the case of a Banach
space, the normality of the cone is also necessary for the completeness of the
Thompson metric.


title:
Macroscopically measurable force induced by temperature discontinuities
  at solid-gas interfaces

abstract:
  We consider a freely movable solid that separates a long tube into two
regions, each of which is filled with a dilute gas. The gases in each region
are initially prepared at the same pressure but different temperatures. Under
the assumption that the pressure and temperatures of gas particles before
colliding with the solid are kept constant over time, we show that temperature
gaps appearing on the solid surface generate a force. We provide a quantitative
estimation of the force, which turns out to be large enough to be observed by a
macroscopic measurement.


title:
Persistent currents in absence of magnetic field in graphene nanorings:
  The ambiguous role of inter valley scattering

abstract:
  Persistent currents can arise in normal-metal rings due to a magnetic flux
threading the ring in equilibrium. However, can persistent currents arise in
absence of magnetic flux in the same normal-metal rings? Yes they can but in a
non-equilibrium set-up. This is known as current magnification. In this work we
show that current magnification can be seen in graphene nanorings. Further,
graphene can have electrons polarized with a valley quantum number. Electron
scattering between valleys can have a non-trivial effect on these persistent
currents including inducing a sign change and generating them for parameters
where none existed to begin with.


title:
Component separation of two-component fermion clouds in a spin-dependent
  external potential by spin-density-functional theory

abstract:
  We investigate the component separation in one-dimensional two-component
fermion clouds in a spin-dependent external potential. The density
distributions and the state diagram are studied by means of spin-dependent
density-functional theory. The component separation between spin-up and
spin-down atoms is induced by the interplay of the spin-dependent harmonic
confinement and the strong repulsive interaction between the inter-components.
We find the existence of a threshold repulsive interaction strength above which
the component separation evolves. Different state diagrams are mapped out
numerically, from which two regions are distinguished, i.e., the phase-mixed
region with both spin-up and spin-down mixtures in the center of the trap and
the phase-separated region with only spin-up atoms remaining in the center.


title: Frank McClean and the Ferncliffe Observatory at Tunbridge Wells

abstract:
  This short note describes the observatory of the pioneering spectroscopist,
Frank McClean (1837-1907), at Tunbridge Wells in England


title:
First-principles molecular dynamics simulations of proton diffusion in
  cubic BaZrO3 perovskite under strain conditions

abstract:
  First-principles molecular dynamics simulations have been employed to analyze
the proton diffusion in cubic BaZrO3 perovskite at 1300K, and a non-linear
effect of an applied isometric strain of 2% on the lattice parameter has been
observed. The structural and electronic properties of BaZrO3 are analyzed,
based on Density Functional Theory calculations, and after an analysis of the
electronic structure, we provide a possible explanation for an enhanced ionic
conductivity, that can be caused by the formation of a preferential path for
proton diffusion under compressive strain conditions.


title: Diffusive Molecular Communication with Disruptive Flows

abstract:
  In this paper, we study the performance of detectors in a diffusive molecular
communication environment where steady uniform flow is present. We derive the
expected number of information molecules to be observed in a passive spherical
receiver, and determine the impact of flow on the assumption that the
concentration of molecules throughout the receiver is uniform. Simulation
results show the impact of advection on detector performance as a function of
the flow's magnitude and direction. We highlight that there are disruptive
flows, i.e., flows that are not in the direction of information transmission,
that lead to an improvement in detector performance as long as the disruptive
flow does not dominate diffusion and sufficient samples are taken.


title: PO and PN in the wind of the oxygen-rich AGB star IK Tau

abstract:
  Phosphorus-bearing compounds have only been studied in the circumstellar
environments (CSEs) of the asymptotic giant branch (AGB) star IRC +10216 and
the protoplanetary nebula CRL 2688, both C-rich objects, and the O-rich red
supergiant VY CMa. The current chemical models cannot reproduce the high
abundances of PO and PN derived from observations of VY CMa. No observations
have been reported of phosphorus in the CSEs of O-rich AGB stars. We aim to set
observational constraints on the phosphorous chemistry in the CSEs of O-rich
AGB stars, by focussing on the Mira-type variable star IK Tau. Using the IRAM
30m telescope and the Submillimeter Array (SMA), we observed four rotational
transitions of PN (J=2-1,3-2,6-5,7-6) and four of PO
(J=5/2-3/2,7/2-5/2,13/2-11/2,15/2-13/2). The IRAM 30m observations were
dedicated line observations, while the SMA data come from an unbiased spectral
survey in the frequency range 279-355 GHz.
  We present the first detections of PN and PO in an O-rich AGB star and
estimate abundances X(PN/H2) of about 3x10^-7 and X(PO/H2) in the range
0.5-6.0x10^-7. This is several orders of magnitude higher than what is found
for the C-rich AGB star IRC +10216. The diameter (<=0.7") of the PN and PO
emission distributions measured in the interferometric data corresponds to a
maximum radial extent of about 40 stellar radii. The abundances and the spatial
occurrence of the molecules are in very good agreement with the results
reported for VY CMa. We did not detect PS or PH3 in the survey. We suggest that
PN and PO are the main carriers of phosphorus in the gas phase, with abundances
possibly up to several 10^-7. The current chemical models cannot account for
this, underlining the strong need for updated chemical models that include
phosphorous compounds.


title: The Reverend Walter Bidlake of Crewe

abstract:
  The Reverend Walter Bidlake, MA, FRAS, JP (1865-1938) was vicar of Crewe,
England, for some 21 years. A member of the BAA, he was a keen amateur
astronomer with an interest in celestial photography. At the request of another
well-known BAA member, T.H.E.C. Espin, Bidlake took photographs of the night
sky in support of Espin's search for dark nebulae in the Milky Way. This paper
describes Bidlake's astronomical activities and life, including a high profile
libel case he brought.


title:
On the univeral \alpha-central extensions of the semi-direct product of
  Hom-Leibniz algebras

abstract:
  We introduce Hom-actions, semi-direct product and establish the equivalence
between split extensions and the semi-direct product extension of Hom-Leibniz
algebras. We analyze the functorial properties of the universal
({\alpha})-central extensions of ({\alpha})-perfect Hom-Leibniz algebras. We
establish under what conditions an automorphism or a derivation can be lifted
in an {\alpha}-cover and we analyze the universal {\alpha}-central extension of
the semi-direct product of two {\alpha}-perfect Hom-Leibniz algebras.


title: The British Astronomical Association and the Great War of 1914-1918

abstract:
  Marking the centenary of the outbreak of the First World War, this paper
considers the effect of the war on the BAA and pays tribute to some of its
members who were involved in the conflict.


title: New Algorithms for Solving Tropical Linear Systems

abstract:
  The problem of solving tropical linear systems, a natural problem of tropical
mathematics, has already proven to be very interesting from the algorithmic
point of view: it is known to be in $NP\cap coNP$ but no polynomial time
algorithm is known, although counterexamples for existing pseudopolynomial
algorithms are (and have to be) very complex.
  In this work, we continue the study of algorithms for solving tropical linear
systems. First, we present a new reformulation of Grigoriev's algorithm that
brings it closer to the algorithm of Akian, Gaubert, and Guterman; this lets us
formulate a whole family of new algorithms, and we present algorithms from this
family for which no known superpolynomial counterexamples work. Second, we
present a family of algorithms for solving overdetermined tropical systems. We
show that for weakly overdetermined systems, there are polynomial algorithms in
this family. We also present a concrete algorithm from this family that can
solve a tropical linear system defined by an $m\times n$ matrix with maximal
element $M$ in time $\Theta\left({m \choose n} \mathrm{poly}\left(m, n, \log
M\right)\right)$, and this time matches the complexity of the best of
previously known algorithms for feasibility testing.


title: Quantum Gravity: physics from supergeometries

abstract:
  We show that the metric (line element) is the first geometrical object to be
associated to a discrete (quantum) structure of the spacetime without necessity
of black hole-entropy-area arguments, in sharp contrast with other attempts in
the literature. To this end, an emergent metric solution obtained previously in
[Physics Letters B 661, 186-191 (2008)] from a particular non-degenerate
Riemmanian superspace is introduced. This emergent metric is described by a
physical coherent state belonging to the metaplectic group Mp (n) with a
Poissonian distribution at lower n (number basis) restoring the classical
thermal continuum behaviour at large n (n ! 1), or leading to non-classical
radiation states, as is conjectured in a quite general basis by mean the
Bekenstein- Mukhanov effect. Group-dependent conditions that control the
behavior of the macroscopic regime spectrum (thermal or not), as the
relationship with the problem of area / entropy of the black hole are presented
and discussed.


title: Hypergeometric Functions II (q-analogues)

abstract:
  This is the typewritten version of a handwritten manuscript which was
completed by Ian G. Macdonald in 1987 or 1988. It is the sequel to the
manuscript "Hypergeometric functions I." The two manuscripts are very informal
working papers, never intended for formal publication. Nevertheless, copies of
the manuscripts have circulated widely, giving rise to quite a few citations in
the subsequent 25 years. Therefore it seems justified to make the manuscripts
available for the whole mathematical community. The author kindly gave his
permission that typewritten versions be posted on arXiv.


title:
Essential plasticity and redundancy of metabolism unveiled by synthetic
  lethality analysis

abstract:
  We unravel how functional plasticity and redundancy are essential mechanisms
underlying the ability to survive of metabolic networks. We perform an
exhaustive computational screening of synthetic lethal reaction pairs in
Escherichia coli in a minimal medium and we find that synthetic lethal pairs
divide in two different groups depending on whether the synthetic lethal
interaction works as a backup or as a parallel use mechanism, the first
corresponding to essential plasticity and the second to essential redundancy.
In E. coli, the analysis of pathways entanglement through essential redundancy
supports the view that synthetic lethality affects preferentially a single
function or pathway. In contrast, essential plasticity, the dominant class,
tends to be inter-pathway but strongly localized and unveils Cell Envelope
Biosynthesis as an essential backup for Membrane Lipid Metabolism. When
comparing E. coli and Mycoplasma pneumoniae, we find that the metabolic
networks of the two organisms exhibit a large difference in the relative
importance of plasticity and redundancy which is consistent with the conjecture
that plasticity is a sophisticated mechanism that requires a complex
organization. Finally, coessential reaction pairs are explored in different
environmental conditions to uncover the interplay between the two mechanisms.
We find that synthetic lethal interactions and their classification in
plasticity and redundancy are basically insensitive to medium composition, and
are highly conserved even when the environment is enriched with nonessential
compounds or overconstrained to decrease maximum biomass formation.


title:
Evidence for Orbital Order and its Relation to Superconductivity in
  FeSe0.4Te0.6

abstract:
  The emergence of nematic electronic states accompanied by a structural phase
transition is a recurring theme in many correlated electron materials,
including the high-temperature copper oxide- and iron-based superconductors. We
provide evidence for nematic electronic states in the iron-chalcogenide
superconductor FeSe0.4Te0.6 from quasi-particle scattering detected in
spectroscopic maps. The symmetry-breaking states persist above Tc into the
normal state. We interpret the scattering patterns by comparison with
quasi-particle interference patterns obtained from a tight-binding model,
accounting for orbital ordering. The relation to superconductivity and the
influence on the coherence length are discussed.


title: mTim: Rapid and accurate transcript reconstruction from RNA-Seq data

abstract:
  Recent advances in high-throughput cDNA sequencing (RNA-Seq) technology have
revolutionized transcriptome studies. A major motivation for RNA-Seq is to map
the structure of expressed transcripts at nucleotide resolution. With accurate
computational tools for transcript reconstruction, this technology may also
become useful for genome (re-)annotation, which has mostly relied on de novo
gene finding where gene structures are primarily inferred from the genome
sequence. We developed a machine-learning method, called mTim (margin-based
transcript inference method) for transcript reconstruction from RNA-Seq read
alignments that is based on discriminatively trained hidden Markov support
vector machines. In addition to features derived from read alignments, it
utilizes characteristic genomic sequences, e.g. around splice sites, to improve
transcript predictions. mTim inferred transcripts that were highly accurate and
relatively robust to alignment errors in comparison to those from Cufflinks, a
widely used transcript assembly method.


title:
System-size independence of a large deviation function for frequency of
  events in a one-dimensional forest-fire model with a single ignition site

abstract:
  It is found that a large deviation function for frequency of events of size
not equal to the system size in the one dimensional forest-fire model with a
single ignition site at an edge is independent of the system size, by using an
exact "decomposition" of the modified transition matrix of a master equation.
An exchange in the largest eigenvalue of the modified transition matrix may not
occur in the model.


title: First high-resolution images of the Sun in the 2796 \AA{} Mg II k line

abstract:
  We present the first high-resolution solar images in the Mg II k 2796 \AA{}
line. The images, taken through a 4.8 \AA{} broad interference filter, were
obtained during the second science flight of SUNRISE in June 2013 by the SuFI
instrument. The Mg II k images display structures that look qualitatively very
similar to images taken in the core of Ca II H. The Mg II images exhibit
reversed granulation (or shock waves) in the internetwork regions of the quiet
Sun, at intensity contrasts that are similar to those found in Ca II H. Very
prominent in Mg II are bright points, both in the quiet Sun and in plage
regions, particularly near disk center. These are much brighter than at other
wavelengths sampled at similar resolution. Furthermore, Mg II k images also
show fibril structures associated with plage regions. Again, the fibrils are
similar to those seen in Ca II H images, but tend to be more pronounced,
particularly in weak plage.


title: The Electron Capture $^{163}$Ho Experiment ECHo: an overview

abstract:
  The determination of the absolute scale of the neutrino masses is one of the
most challenging present questions in particle physics. The most stringent
limit, $m(\bar{\nu}_{\mathrm{e}})<2$eV, was achieved for the electron
anti-neutrino mass \cite{numass}. Different approaches are followed to achieve
a sensitivity on neutrino masses in the sub-eV range. Among them, experiments
exploring the beta decay or electron capture of suitable nuclides can provide
information on the electron neutrino mass value. We present the Electron
Capture $^{163}$Ho experiment ECHo, which aims to investigate the electron
neutrino mass in the sub-eV range by means of the analysis of the
calorimetrically measured energy spectrum following electron capture of
$^{163}$Ho. A high precision and high statistics spectrum will be measured with
arrays of metallic magnetic calorimeters. We discuss some of the essential
aspects of ECHo to reach the proposed sensitivity: detector optimization and
performance, multiplexed readout, $^{163}$Ho source production and
purification, as well as a precise theoretical and experimental
parameterization of the calorimetric EC spectrum including in particular the
value of $Q_{\mathrm{EC}}$. We present preliminary results obtained with a
first prototype of single channel detectors as well as a first 64-pixel chip
with integrated micro-wave SQUID multiplexer, which will already allow to
investigate $m(\nu_{\mathrm{e}})$ in the eV range.


title: Enumerating Regular Objects associated with Suzuki Groups

abstract:
  We use the M\"obius function of the simple Suzuki group Sz(q) to enumerate
regular objects such as maps, hypermaps, dessins d'enfants and surface
coverings with automorphism groups isomorphic to Sz(q).


title: The A_{2n}^{(2)} Rogers-Ramanujan identities

abstract:
  The famous Rogers-Ramanujan and Andrews--Gordon identities are embedded in a
doubly-infinite family of Rogers-Ramanujan-type identities labelled by positive
integers m and n. For fixed m and n the product side corresponds to a
specialised character of the affine Kac-Moody algebra A_{2n}^{(2)} at level m,
and is expressed as a product of n^2 theta functions of modulus 2m+2n+1, or by
level-rank duality, as a product of m^2 theta functions. Rogers-Ramanujan-type
identities for even moduli, corresponding to the affine Lie algebras C_n^{(1)}
and D_{n+1}^{(2)}, are also proven.


title: Understanding H-defect complexes in ZnO

abstract:
  From state-of-the-art density-functional calculations using hybrid
functionals we show that, persistent $n$-type conductivity in ZnO is due to
defect complexes formed between H with intrinsic and extrinsic defects. H
exhibits cationic, anionic, and electrically-inactive character on interacting
with defects in ZnO. The electrically-inactive molecular hydrogen can
contribute to $n$-type conductivity in ZnO by activating deep donor levels into
shallow levels. By calculating local vibrational mode frequencies, we have
identified origins of many H-related Raman and infra-red frequencies and thus
confirmed the amphoteric behavior of H.


title:
High values of Ferroelectric polarization and magnetic susceptibility in
  BFO nanorods

abstract:
  Remarkably high values of polarization as well as a significant magnetic
susceptibility have been observed in multiferroic Bismuth Ferrite (BFO) in the
form of nanorods protruding out. These were developed on porous Anodised
Alumina (AAO) templates using wet chemical technique. Diameters of nanorods are
in the range of 20-100 nm. The high values of polarization and magnetic
susceptibility are attributed to the BFO nanorod structures giving rise to the
directionality. There is no leakage current in P-E loop examined at various
frequencies. Magnetocapacitance measurements reflect a significant enhancement
in magnetoelectric coupling also.


title: Regular dessins with a given automorphism group

abstract:
  Dessins d'enfants are combinatorial structures on compact Riemann surfaces
defined over algebraic number fields, and regular dessins are the most
symmetric of them. If G is a finite group, there are only finitely many regular
dessins with automorphism group G. It is shown how to enumerate them, how to
represent them all as quotients of a single regular dessin U(G), and how
certain hypermap operations act on them. For example, if G is a cyclic group of
order n then U(G) is a map on the Fermat curve of degree n and genus
(n-1)(n-2)/2. On the other hand, if G=A_5 then U(G) has genus
274218830047232000000000000000001. For other non-abelian finite simple groups,
the genus is much larger.


title:
Exploring the Memory-Bandwidth Tradeoff in an Information-Centric
  Network

abstract:
  An information-centric network should realize significant economies by
exploiting a favourable memory-bandwidth tradeoff: it is cheaper to store
copies of popular content close to users than to fetch them repeatedly over the
Internet. We evaluate this tradeoff for some simple cache network structures
under realistic assumptions concerning the size of the content catalogue and
its popularity distribution. Derived cost formulas reveal the relative impact
of various cost, traffic and capacity parameters, allowing an appraisal of
possible future network architectures. Our results suggest it probably makes
more sense to envisage the future Internet as a loosely interconnected set of
local data centers than a network like today's with routers augmented by
limited capacity content stores.


title: A multi-dimensional numerical scheme for two-fluid Relativistic MHD

abstract:
  The paper describes an explicit multi-dimensional numerical scheme for
Special Relativistic Two-Fluid Magnetohydrodynamics of electron-positron plasma
and a suit of test problems. The scheme utilizes Cartesian grid and the third
order WENO interpolation. The time integration is carried out using the third
order TVD method of Runge-Kutta type, thus ensuring overall third order
accuracy on smooth solutions. The magnetic field is kept near divergence-free
by means of the method of generalized Lagrange multiplier. The test
simulations, which include linear and non-linear continuous plasma waves, shock
waves, strong explosions and the tearing instability, show that the scheme is
sufficiently robust and confirm its accuracy.


title: Signed tree associahedra

abstract:
  An associahedron is a polytope whose vertices correspond to the
triangulations of a convex polygon and whose edges correspond to flips between
them. A particularly elegant realization of the associahedron, due to S.
Shnider and S. Sternberg and popularized by J.-L. Loday, has been generalized
in two directions: on the one hand by A. Postnikov to obtain a realization of
the graph associahedra of M. Carr and S. Devadoss, and on the other hand by C.
Hohlweg and C. Lange to obtain multiple realizations of the associahedron
parametrized by a sequence of signs. The goal of this paper is to unify and
extend these two constructions to signed tree associahedra.
  We define the notions of signed tubes and signed nested sets on a
vertex-signed tree, generalizing the classical notions of tubes and nested sets
for unsigned trees. The resulting signed nested complexes are all simplicial
spheres, but they are not necessarily isomorphic, even if they arise from
signed trees with the same underlying unsigned structure. We then construct a
signed tree associahedron realizing the signed nested complex, obtained by
removing certain well-chosen facets from the classical permutahedron. We study
relevant properties of its normal fan and of certain orientations of its
1-skeleton, in connection to the braid arrangement and to the weak order. Our
main tool, both for combinatorial and geometric perspectives, is the notion of
spines on a vertex-signed tree, which extend the families of Schr\"oder and
binary search trees.


title:
JRC EuroVoc Indexer JEX - A freely available multi-label categorisation
  tool

abstract:
  EuroVoc (2012) is a highly multilingual thesaurus consisting of over 6,700
hierarchically organised subject domains used by European Institutions and many
authorities in Member States of the European Union (EU) for the classification
and retrieval of official documents. JEX is JRC-developed multi-label
classification software that learns from manually labelled data to
automatically assign EuroVoc descriptors to new documents in a profile-based
category-ranking task. The JEX release consists of trained classifiers for 22
official EU languages, of parallel training data in the same languages, of an
interface that allows viewing and amending the assignment results, and of a
module that allows users to re-train the tool on their own document
collections. JEX allows advanced users to change the document representation so
as to possibly improve the categorisation result through linguistic
pre-processing. JEX can be used as a tool for interactive EuroVoc descriptor
assignment to increase speed and consistency of the human categorisation
process, or it can be used fully automatically. The output of JEX is a
language-independent EuroVoc feature vector lending itself also as input to
various other Language Technology tasks, including cross-lingual clustering and
classification, cross-lingual plagiarism detection, sentence selection and
ranking, and more.


title: Current hot spot in the spin-valley blockade in carbon nanotubes

abstract:
  We present a theoretical study of the spin-valley blockade transport effect
in a double quantum dot defined in a straight carbon nanotube. We find that
intervalley scattering due to short-range impurities completely lifts the
spin-valley blockade and induces a large leakage current in a certain confined
range of the external magnetic field vector. This current hot spot emerges due
to different effective magnetic fields acting on the spin-valley qubit states
of the two quantum dots. Our predictions are compared to a recent measurement
[F. Pei et al., Nat. Nanotech. 7, 630 (2012)]. We discuss the implications for
blockade-based schemes for qubit initialization/readout, and motion sensing of
nanotube-based mechanical resonators.


title:
Self-assembly in chains, rings and branches: a single component system
  with two critical points

abstract:
  We study the interplay between phase separation and self-assembly in chains,
rings and branched structures in a model of particles with dissimilar patches.
We extend Wertheim's first order perturbation theory to include the effects of
ring formation and theoretically investigate the thermodynamics of the model.
We find a peculiar shape for the vapor-liquid coexistence, featuring re-entrant
behavior in both phases and two critical points, despite the single-component
nature of the system. The emergence of the lower critical point is caused by
the self-assembly of rings taking place in the vapor, generating a phase with
lower energy and lower entropy than the liquid. Monte Carlo simulations of the
same model fully support these unconventional theoretical predictions.


title: DGT-TM: A freely Available Translation Memory in 22 Languages

abstract:
  The European Commission's (EC) Directorate General for Translation, together
with the EC's Joint Research Centre, is making available a large translation
memory (TM; i.e. sentences and their professionally produced translations)
covering twenty-two official European Union (EU) languages and their 231
language pairs. Such a resource is typically used by translation professionals
in combination with TM software to improve speed and consistency of their
translations. However, this resource has also many uses for translation studies
and for language technology applications, including Statistical Machine
Translation (SMT), terminology extraction, Named Entity Recognition (NER),
multilingual classification and clustering, and many more. In this reference
paper for DGT-TM, we introduce this new resource, provide statistics regarding
its size, and explain how it was produced and how to use it.


title: Effective cutting of a quantum spin chain by bond impurities

abstract:
  Spin chains are promising media for short-haul quantum communication. Their
usefulness is manifested in all those situations where stationary information
carriers are involved. In the majority of the communication schemes relying on
quantum spin chains, the latter are assumed to be finite in length, with well
addressable end-chain spins. In this paper we propose that such configuration
could actually be achieved by a mechanism that is able to effectively cut a
spin ring through the insertion of bond defects. We then show how suitable
physical quantities can be identified as figures of merit for the effectiveness
of the cut. We find that, even for modest strengths of the bond defect, a ring
is effectively cut at the defect site. In turn, this has important effects on
the amount of correlations shared by the spins across the resulting chain,
which we study by means of a scattering-based mechanism of a clear physical
interpretation.


title:
Quasiparticle interaction function in a 2D Fermi liquid near an
  antiferromagnetic critical point

abstract:
  We present the expression for the quasiparticle vertex function
$\Gamma^{\omega }(K_{F},P_{F})$ (proportional to the Landau function) in a 2D
Fermi liquid (FL) near a $T=0$ instability towards antiferromagnetism. Previous
studies have found that near an instability, the system enters into a critical
FL regime, in which the fermionic self-energy is large near hot spots (points
on the Fermi surface connected by the antiferromagnetic ordering vector
$q_\pi=(\pi,\pi)$) and has much stronger dependence on frequency than on
momentum. We show that to properly calculate the vertex function in this regime
one has to sum up an infinite series of terms which were explicitly excluded in
the conventional treatment. Besides, we show that, to properly describe the
spin component of $\Gamma^{\omega }(K_{F},P_{F})$ even in an ordinary FL, one
has to include Aslamazov-Larkin terms. We show that the total $\Gamma^{\omega
}(K_{F},P_{F})$ is larger in a critical FL than in an ordinary FL, roughly by
an extra power of magnetic correlation length $\xi$. However, the enhancement
of $\Gamma ^{\omega }(K_{F},P_{F})$ is highly non-uniform: It holds only when,
for one of the two momentum variables, the distance from a hot spot along the
Fermi surface is much larger than for the other one. We show that the charge
and spin components of the total vertex function satisfy the universal
relations following from the Ward identities related to the conservation of the
particle number and the total spin. We find that the charge and spin components
of $\Gamma^{\omega }(K_{F},P_{F})$ are identical to leading order in the
magnetic correlation length. We derive the Landau parameters, the density of
states $N_F$, and the uniform ($q=0$) charge and spin susceptibilities $\chi
^{l=0}_{c} = \chi^{l=0}_s$. We show that the susceptibilities remain finite at
$\xi = \infty$ despite that $N_F$ diverges as $\log \xi$.


title: Opportunistic Migration in Spatial Evolutionary Games

abstract:
  We study evolutionary games in a spatial diluted grid environment in which
agents strategically interact locally but can also opportunistically move to
other positions within a given migration radius. Using the imitation of the
best rule for strategy revision, it is shown that cooperation may evolve and be
stable in the Prisoner's Dilemma game space for several migration distances but
only for small game interaction radius while the Stag Hunt class of games
become fully cooperative. We also show that only a few trials are needed for
cooperation to evolve, i.e. searching costs are not an issue. When the
stochastic Fermi strategy update protocol is used cooperation cannot evolve in
the Prisoner's Dilemma if the selection intensity is high in spite of
opportunistic migration. However, when imitation becomes more random, fully or
partially cooperative states are reached in all games for all migration
distances tested and for short to intermediate interaction radii.


title:
Anomalously Strong Nonlinearity of Unswept Quartz Acoustic Cavities at
  Liquid Helium Temperatures

abstract:
  We demonstrate a variety of nonlinear phenomena at extremely low powers in
cryogenic acoustic cavities fabricated from quartz material, which have not
undergone any electrodiffusion processes. Nonlinear phenomena observed include
lineshape discontinuities, power response discontinuities, quadrature
oscillations and self-induced transparency. These phenomena are attributed to
nonlinear dissipation through a large number of randomly distributed heavy
trapped ions, which would normally be removed by electrodiffusion. A simple
mean-field model predicts most of the observed phenomena. In contrast to
Duffing-like systems, this system shows an unusual mechanism of nonlinearity,
which is not related to crystal anharmonisity.


title: Radiation hydrodynamics integrated in the code PLUTO

abstract:
  The transport of energy through radiation is very important in many
astrophysical phenomena. In dynamical problems the time-dependent equations of
radiation hydrodynamics have to be solved. We present a newly developed
radiation-hydrodynamics module specifically designed for the versatile MHD code
PLUTO. The solver is based on the flux-limited diffusion approximation in the
two-temperature approach. All equations are solved in the co-moving frame in
the frequency independent (grey) approximation. The hydrodynamics is solved by
the different Godunov schemes implemented in PLUTO, and for the radiation
transport we use a fully implicit scheme. The resulting system of linear
equations is solved either using the successive over-relaxation (SOR) method
(for testing purposes), or matrix solvers that are available in the PETSc
library. We state in detail the methodology and describe several test cases in
order to verify the correctness of our implementation. The solver works in
standard coordinate systems, such as Cartesian, cylindrical and spherical, and
also for non-equidistant grids. We have presented a new radiation-hydrodynamics
solver coupled to the MHD-code \PLUTO that is a modern, versatile and efficient
new module for treating complex radiation hydrodynamical problems in
astrophysics. As test cases, either purely radiative situations, or full
radiation-hydrodynamical setups (including radiative shocks and convection in
accretion discs) have been studied successfully. The new module scales very
well on parallel computers using MPI. For problems in star or planet formation,
we have added the possibility of irradiation by a central source.


title:
Stochastic differential equations driven by G-Brownian motion and
  ordinary differential equations

abstract:
  In this paper, we show that the integration of a stochastic differential
equations driven by G-Brownian motion in R can be reduced to the integration of
an ordinary differential equations parametrized by a variable in ({\Omega},F).
We study the sample solutions of G-SDEs by an extention of G-It\^o formula. And
then we also get a comparison theorem for G-SDEs and its applications.


title: Pulse-wise Amati correlation in Fermi GRBs

abstract:
  We make a detailed pulse-wise study of gamma-ray bursts (GRBs) with known
redshift detected by \emph{Fermi}/Gamma Ray Burst Monitor (GBM). The sample
contains 19 GRBs with 43 pulses. We find that the average peak energy is
correlated to the radiated energy (the Amati relation) for individual pulses
with a correlation coefficient of 0.86, which is slightly better than the
correlation for the full GRBs. As the present correlation holds within GRBs, it
is a strong evidence supporting the reliability of such a correlation. We
investigate several aspects of this correlation. (i) We divide our sample into
redshift bins and study the evolution of the correlation. Though there is a
marginal indication of evolution of the correlation, we can conclude that the
present data is consistent with no evolution. (ii) We compare the correlation
in the first or single pulses of these GRBs to that of the rest of the pulses,
and confirm that the correlation is unaffected by the fact that first/single
pulses are generally harder than the rest. Finally, we conclude that the
pulse-wise Amati correlation is more robust and it has the potential of
refining the correlation so that GRB study could be used as a cosmological
tool.


title:
Another brick in understanding chemical and kinematical properties of
  BSSs: NGC 6752

abstract:
  We used high-resolution spectra acquired with the multifiber facility FLAMES
at the Very Large Telescope of the European Southern Observatory to investigate
the chemical and kinematical properties of a sample of 22 Blue Straggler Stars
(BSSs) and 26 red giant branch stars in the nearby globular cluster NGC 6752.
We measured radial and rotational velocities and Fe, O and C abundances.
According to radial velocities, metallicity and proper motions we identified 18
BSSs as likely cluster members. We found that all the BSSs rotate slowly (less
than 40 km/s), similar to the findings in 47 Tucanae, NGC 6397 and M30. The Fe
abundance analysis reveals the presence of 3 BSSs affected by radiative
levitation (showing [Fe/H] significantly higher than that measured in "normal"
cluster stars), confirming that element transport mechanisms occur in the
photosphere of BSSs hotter than 8000 K. Finally, BSS C and O abundances are
consistent with those measured in dwarf stars. No C and O depletion ascribable
to mass transfer processes has been found on the atmospheres of the studied
BSSs (at odds with previous results for 47 Tucanae and M30), suggesting the
collisional origin for BSSs in NGC 6752 or that the CO-depletion is a transient
phenomenon.


title: Optimal Liquidity Provision

abstract:
  A small investor provides liquidity at the best bid and ask prices of a limit
order market. For small spreads and frequent orders of other market
participants, we explicitly determine the investor's optimal policy and
welfare. In doing so, we allow for general dynamics of the mid price, the
spread, and the order flow, as well as for arbitrary preferences of the
liquidity provider under consideration.


title: On planar right groups

abstract:
  In 1896 Heinrich Maschke characterized planar finite groups, that is groups
which admit a generating system such that the resulting Cayley graph is planar.
In our study we consider the question, which finite semigroups have a planar
Cayley graph. Right groups are a class of semigroups relatively close to
groups. We present a complete characterization of planar right groups.


title:
Global SAXS data analysis for multilamellar vesicles: Evolution of the
  scattering density profile (SDP) model

abstract:
  We adapted the highly successful scattering density profile (SDP) model,
which is used to jointly analyze small angle x-ray and neutron scattering data
from unilamellar vesicles, for use with data from fully hydrated, liquid
crystalline multilamellar vesicles (MLVs). By using a genetic algorithm, this
new method is capable of providing high resolution structural information, as
well as determining bilayer elastic bending fluctuations from standalone x-ray
data. Important structural parameters, such as bilayer thickness and area per
lipid were determined for a series of saturated and unsaturated lipids, as well
as binary mixtures with cholesterol. Results are in good agreement with
previously reported SDP data, which used both neutron and x-ray data. The
addition of deuterated and non-deuterated MLV neutron data to the analysis
improved lipid backbone information, but did not improve, within experimental
uncertainties, the structural information regarding bilayer thickness and area
per lipid.


title: Nonlocal Granular Rheology: Role of Pressure and Anisotropy

abstract:
  We probe the secondary rheology of granular media, by imposing a main flow
and immersing a vane-shaped probe into the slowly flowing granulate. The
secondary rheology is then the relation between the exerted torque T and
rotation rate \omega of our probe. In the absence of any main flow, the probe
experiences a clear yield-stress, whereas for any finite flow rate, the yield
stress disappears and the secondary rheology takes on the form of a double
exponential relation between \omega and T. This secondary rheology does not
only depend on the magnitude of T, but is anisotropic --- which we show by
varying the relative orientation of the probe and main flow. By studying the
depth dependence of the three characteristic torques that characterize the
secondary rheology, we show that for counter flow, the dominant contribution is
frictional like --- i.e., T and pressure are proportional for given \omega ---
whereas for co flow, the situation is more complex. Our experiments thus reveal
the crucial role of anisotropy for the rheology of granular media.


title: SALT reveals the barium central star of the planetary nebula Hen 2-39

abstract:
  Classical barium stars are binary systems which consist of a late-type giant
enriched in carbon and slow neutron capture (s-process) elements and an evolved
white dwarf (WD) that is invisible at optical wavelengths. The youngest
observed barium stars are surrounded by planetary nebulae (PNe), ejected soon
after the wind accretion of polluted material when the WD was in its preceeding
asymptotic giant branch (AGB) phase. Such systems are rare but powerful
laboratories for studying AGB nucleosynthesis as we can measure the chemical
abundances of both the polluted star and the nebula ejected by the polluter.
Here we present evidence for a barium star in the PN Hen 2-39. The polluted
giant is very similar to that found in WeBo 1. It is a cool (Teff=4250 +/- 150
K) giant enhanced in carbon ([C/H]=0.42 +/- 0.02 dex) and barium ([Ba/Fe]=1.50
+/- 0.25 dex). A spectral type of C-R3 C_24 nominally places Hen 2-39 amongst
the peculiar early R-type carbon stars, however the barium enhancement and
likely binary status mean that it is more likely to be a barium star with
similar properties, rather than a true member of this class. An AGB star model
of initial mass 1.8 Msun and a relatively large carbon pocket size can
reproduce the observed abundances well, provided mass is transferred in a
highly conservative way from the AGB star to the polluted star (e.g. wind
Roche-lobe overflow). The nebula exhibits an apparent ring morphology in
keeping with the other PNe around barium stars (WeBo 1 and A 70) and shows a
high degree of ionization implying the presence of an invisible hot pre-WD
companion that will require confirmation with UV observations. In contrast to A
70, the nebular chemical abundance pattern is consistent with non-Type I PNe,
in keeping with the trend found from nebular s-process studies that non-Type I
PNe are more likely to be s-process enhanced. (abridged)


title:
Paschen-Back effect in the CrH molecule and its application for magnetic
  field measurements on stars, brown dwarfs, and hot exoplanets

abstract:
  We investigated the Paschen-Back effect in the (0,0) band of the
A6{\Sigma}+-X6{\Sigma}+ system of the CrH molecule, and we examined its
potential for estimating magnetic fields on stars and substellar objects, such
as brown dwarfs and hot exoplanets. We carried out quantum mechanical
calculations to obtain the energy level structure of the
electronic-vibrational-rotational states considered both in the absence and in
the presence of a magnetic field. Level mixing due to magnetic field
perturbation (the Paschen-Back effect) was consistently taken into account.
Then, we calculated frequencies and strengths of transitions between magnetic
sublevels. Employing these results and solving numerically a set of the
radiative transfer equations for polarized radiation, we calculated Stokes
parameters for both the individual lines and the (0,0) band depending on the
strength and orientation of the magnetic field. We demonstrate that magnetic
splitting of the individual CrH lines shows a significant asymmetry due to the
Paschen-Back effect already at 1 G field. This leads to a considerable signal
in both circular and linear polarization, up to 30 percent at the magnetic
field strength of more than 3 kG in early L dwarfs. The polarization does not
cancel out completely even at very low spectral resolution and is seen as
broad-band polarization of a few percent. Since the line asymmetry depends only
on the magnetic field strength and not on the filling factor, CrH lines provide
a very sensitive tool for direct measurement of the stellar magnetic fields on
faint cool objects, such as brown dwarfs and hot Jupiters, observed with low
spectral resolution.


title: Extreme Current Fluctuations in a Nonstationary Stochastic Heat Flow

abstract:
  We employ the Hamiltonian formalism of macroscopic fluctuation theory to
study large deviations of integrated current in the Kipnis-Marchioro-Presutti
(KMP) model of stochastic hear flow when starting from a step-like initial
condition. The KMP model belongs to the hyperbolic universality class where
diffusion remains relevant no matter how large the fluctuating current is. The
extreme current statistics for the KMP model turns out to be sub-Gaussian, as
distinguished from the super-Gaussian statistics found for the Symmetric Simple
Exclusion Process and other models of the elliptic class. The most probable
time history of the system, which dominates the extreme current statistics of
the KMP model, involves two large-amplitude solitary pulses: of the energy
density field and of the conjugate "momentum" field. The coupled pulses
propagate with a constant speed, but their amplitudes slowly grow with time, as
the energy density pulse collects most of the available energy on its way.


title:
Radial sign-changing solutions to biharmonic nonlinear Schr\"odinger
  equations

abstract:
  In this work we obtain three radial solutions of a biharmonic stationary
Schr\"odinger equation, being one positive, one negative and one that changes
sign. The Dual Decompostion Method is used to split the natural second order
Sobolev space considered in order to apply the appropriate variational
approach.


title: Algorithms for Mumford curves

abstract:
  Mumford showed that Schottky subgroups of $PGL(2,K)$ give rise to certain
curves, now called Mumford curves, over a non-Archimedean field K. Such curves
are foundational to subjects dealing with non-Archimedean varieties, including
Berkovich theory and tropical geometry. We develop and implement numerical
algorithms for Mumford curves over the field of p-adic numbers. A crucial and
difficult step is finding a good set of generators for a Schottky group, a
problem solved in this paper. This result allows us to design and implement
algorithms for tasks such as: approximating the period matrices of the
Jacobians of Mumford curves; computing the Berkovich skeleta of their
analytifications; and approximating points in canonical embeddings. We also
discuss specific methods and future work for hyperelliptic Mumford curves.


title: Why do Earth satellites stay up?

abstract:
  Satellites in low Earth orbits must accurately conserve their orbital
eccentricity, since a decrease in perigee of only 5-10% would cause them to
crash. However, these satellites are subject to gravitational perturbations
from the Earth's multipole moments, the Moon, and the Sun that are not
spherically symmetric and hence do not conserve angular momentum, especially
over the tens of thousands of orbits made by a typical satellite. Why then do
satellites not crash? We describe a vector-based analysis of the long-term
behavior of satellite orbits and apply this to several toy systems containing a
single non-Keplerian perturbing potential. If only the quadrupole potential
from the Earth's equatorial bulge is present, all near-circular orbits are
stable. If only the octupole potential is present, all such orbits are
unstable. If only the lunar or solar potential is present, all near-circular
orbits with inclinations to the ecliptic exceeding 39 degrees are unstable. We
describe the behavior of satellites in the simultaneous presence of all of
these perturbations and show that almost all low Earth orbits are stable
because of an accidental property of the dominant quadrupole potential. We also
relate these results to the phenomenon of Lidov-Kozai oscillations.


title:
Credit Risk and the Instability of the Financial System: an Ensemble
  Approach

abstract:
  The instability of the financial system as experienced in recent years and in
previous periods is often linked to credit defaults, i.e., to the failure of
obligors to make promised payments. Given the large number of credit contracts,
this problem is amenable to be treated with approaches developed in statistical
physics. We introduce the idea of ensemble averaging and thereby uncover
generic features of credit risk. We then show that the often advertised concept
of diversification, i.e., reducing the risk by distributing it, is deeply
flawed when it comes to credit risk. The risk of extreme losses remain due to
the ever present correlations, implying a substantial and persistent intrinsic
danger to the financial system.


title:
Ram pressure stripping of the hot gaseous haloes of galaxies using the
  k-epsilon sub-grid turbulence model

abstract:
  We perform three dimensional hydrodynamic simulations of the ram pressure
stripping of the hot extended gaseous halo of a massive galaxy using the
k-epsilon sub-grid turbulence model at Mach numbers 0.9, 1.1 and 1.9. The
k-epsilon model is used to simulate high Reynolds number flows by increasing
the transport coefficients in regions of high turbulence. We find that the
initial, instantaneous stripping is the same whether or not the k-epsilon model
is implemented and is in agreement with the results of other studies. However
the use of the k-epsilon model leads to five times less gas remaining after
stripping by a supersonic flow has proceeded for 10 Gyr, which is more
consistent with what simple analytic calculations indicate. Hence the continual
Kelvin-Helmholtz stripping plays a significant role in the ram pressure
stripping of the haloes of massive galaxies. To properly account for this,
simulations of galaxy clusters will require the use of sub-grid turbulence
models


title:
Rotating Non-Uniform and High-Dimensional Constellations Using Geodesic
  Flow on Lie Groups

abstract:
  We use a numerical algorithm on the Lie group of rotation matrices to obtain
rotated constellations for Rayleigh fading channels. Our approach minimizes the
union bound for the pairwise error probability to produce rotations optimized
for a given signal-to-noise ratio. This approach circumvents explicit
parametrization of rotation matrices, which has previously prevented robust
numerical methods from being applied to constellation rotation. Our algorithm
is applicable to arbitrary finite constellations in arbitrary dimensions, and
one can thus apply our method to non-uniform constellations, which are of
interest for practical concerns due to their ability to increase BICM capacity.
We show how our rotations can improve the codeword error performance of
non-uniform constellations, and we also apply our method to reproduce and
improve rotations given by ideal lattices in cyclotomic fields.


title: Coexistence of effects from an algebra of two projections

abstract:
  The coexistence relation of quantum effects is a fundamental structure,
describing those pairs of experimental events that can be implemented in a
single setup. Only in the simplest case of qubit effects an analytic
characterization of coexistent pairs is known. We generalize the qubit
coexistence characterization to all pairs of effects in arbitrary dimension
that belong to the von Neumann algebra generated by two projections. We
demonstrate the presented mathematical machinery by several examples, and show
that it covers physically relevant classes of effect pairs.


title:
Effect of short-range order on transport in one-particle, tight-binding
  models

abstract:
  We investigate transport properties of topologically disordered,
three-dimensional, one-particle, tight binding models, featuring site distance
dependent hopping terms. We start from entirely disordered systems into which
we gradually introduce some short range order by numerically performing a
pertinent structural relaxation using local site-pair interactions. Transport
properties of the resulting models within the delocalized regime are analyzed
numerically using linear response theory. We find that even though the
generated order is very short ranged, transport properties such as conductivity
or mean free path scale significantly with the degree of order. Mean free paths
may exceed site-pair correlation length. It is furthermore demonstrated that,
while the totally disordered model is not in accord with a Drude- or
Boltzmann-type description, moderate degrees of order suffice to render such a
picture valid.


title: Representations of Quantum Affine Superalgebras

abstract:
  We study the quantum affine superalgebra $U_q(Lsl(M,N))$ and its
finite-dimensional representations. We prove a triangular decomposition and
establish a system of Poincar\'{e}-Birkhoff-Witt generators for this
superalgebra, both in terms of Drinfel'd currents. We define the Weyl modules
in the spirit of Chari-Pressley and prove that these Weyl modules are always
finite-dimensional and non-zero. In consequence, we obtain a highest weight
classification of finite-dimensional simple representations when $M \neq N$.
Some concrete simple representations are constructed via evaluation morphisms.


title:
An interferometric view on binarity and circumstellar envelopes of
  Cepheids

abstract:
  Optical interferometry is the only technique giving access to milli-arcsecond
(mas) resolution at infrared wavelengths. For Cepheids, this is a powerful and
unique tool to detect the orbiting companions and the circumstellar envelopes
(CSE). CSEs are interesting because they might be used to trace the Cepheid
evolution history, and more particularly they could impact the distance scale.
Cepheids belonging to binary systems offer an unique opportunity to make
progress in resolving the Cepheid mass discrepancy. The combination of
spectroscopic and interferometric measurements will allow us to derive the
orbital elements, distances, and dynamical masses. Here we focus on recent
results using 2- to 6-telescopes beam combiners for the Cepheids X Sgr, T Mon
and V1334 Cyg.


title: Equilibrium measures and partial balayage

abstract:
  We consider the equilibrium problem for an external background potential in
weighted potential theory, and show that for a large class of background
potentials there is a complementarity relationship between the measure solving
the weighted equilibrium problem - the weighted equilibrium measure - and a
certain partial balayage measure.


title: Quantum walks on embedded hypercubes

abstract:
  It has been proved by Kempe that discrete quantum walks on the hypercube (HC)
hit exponentially faster than the classical analog. The same was also observed
numerically by Krovi and Brun for a slightly different property, namely, the
expected hitting time. Yet, to what extent this striking result survives in
more general graphs, is to date an open question. Here we tackle this question
by studying the expected hitting time for quantum walks on HCs that are
embedded into larger symmetric structures. By performing numerical simulations
of the discrete quantum walk and deriving a general expression for the
classical hitting time, we observe an exponentially increasing gap between the
expected classical and quantum hitting times, not only for walks on the bare
HC, but also for a large family of embedded HCs. This suggests that the quantum
speedup is stable with respect to such embeddings.


title: Substitution Systems and Nonextensive Statistics

abstract:
  Substitution systems evolve in time by generating sequences of symbols from a
finite alphabet: At a certain iteration step, the existing symbols are
systematically replaced by blocks of $N_{k}$ symbols also within the alphabet
(with $N_{k}$, a natural number, being the length of the $k$-th block of the
substitution). The dynamics of these systems leads naturally to fractals and
self-similarity. By using $\mathcal{B}$-calculus [V. Garcia-Morales, Phys.
Lett. A 376 (2012) 2645] universal maps for deterministic substitution systems
both of constant and non-constant length, are formulated in 1D. It is then
shown how these systems can be put in direct correspondence with Tsallis
entropy. A `Second Law of Thermodynamics' is also proved for these systems in
the asymptotic limit of large words.

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


title:
Cryptanalysis of Wu and Xu's authentication scheme for Telecare Medicine
  Information Systems

abstract:
  Remote user authentication is desirable for a Telecare medicine information
system (TMIS) to verify the correctness of remote users. In 2013, Jiang et al.
proposed privacy preserving authentication scheme for TMIS. Recently, Wu and Xu
analyzed Jiang's scheme and identify serious security flaws in their scheme,
namely, user impersonation attack, DoS attack and off-line password guessing
attack. In this article, we analyze Wu and Xu's scheme and show that their
scheme is also vulnerable to off-line password guessing attack and does not
protect user anonymity. Moreover, we identify the inefficiency of incorrect
input detection of the login phase in Wu and Xu's scheme, where the smart card
executes the login session in-spite of wrong input.


title:
Author Name Co-Mention Analysis: Testing a Poor Man's Author Co-Citation
  Analysis Method

abstract:
  As a social science information service for the German language countries, we
document research projects, publications, and data in relevant fields. At the
same time, we aim to provide well-founded bibliometric studies of these fields.
Performing a citation analysis on an area of the German social sciences is,
however, a serious challenge given the low and likely significantly biased
coverage of these fields in the standard citation databases. Citations, and
especially author citations, play a highly significant role in that literature,
however. In this work in progress, we report preliminary methods and results
for an author name co-mention analysis of a large fragment of a particularly
interesting corpus of German sociology: a quarter century's worth of the
full-text proceedings of the Deutsche Gesellschaft fuer Soziologie (DGS), which
celebrated its 100th anniversary meeting in 2012. Results are encouraging for
this poor cousin of author co-citation analysis, but considerable refinements,
especially of the underlying computational infrastructure for full-text
analysis, appear advisable for full-scale deployment of this method.


title: Application of Jitter Radiation: Gamma-ray Burst Prompt Polarization

abstract:
  A high-degree of polarization of gamma-ray burst (GRB) prompt emission has
been confirmed in recent years. In this paper, we apply jitter radiation to
study the polarization feature of GRB prompt emission. In our framework,
relativistic electrons are accelerated by turbulent acceleration. Random and
small-scale magnetic fields are generated by turbulence. We further determine
that the polarization property of GRB prompt emission is governed by the
configuration of the random and small-scale magnetic fields. A two-dimensional
compressed slab, which contains stochastic magnetic fields, is applied in our
model. If the jitter condition is satisfied, the electron deflection angle in
the magnetic field is very small and the electron trajectory can be treated as
a straight line. A high-degree of polarization can be achieved when the angle
between the line of sight and the slab plane is small. Moreover, micro-emitters
with mini-jet structure are considered to be within a bulk GRB jet. The jet
"off-axis" effect is intensely sensitive to the observed polarization degree.
We discuss the depolarization effect on GRB prompt emission and afterglow. We
also speculate that the rapid variability of GRB prompt polarization may be
correlated with the stochastic variability of the turbulent dynamo or the
magnetic reconnection of plasmas.


title: Full result for the QCD equation of state with 2+1 flavors

abstract:
  We present a full result for the 2+1 flavor QCD equation of state. All the
systematics are controlled, the quark masses are set to their physical values,
and the continuum extrapolation is carried out. This extends our previous
studies [JHEP 0601:089 (2006); 1011:077 (2010)] to even finer lattices and now
includes ensembles with Nt = 6,8,10,12 up to Nt = 16. We use a Symanzik
improved gauge and a stout-link improved staggered fermion action. Our findings
confirm our earlier results. In order to facilitate the direct use of our
equation of state we make our tabulated results available for download.


title:
Magnetic properties of quantum rings in the presence of the spin-orbit
  and electron-electron interaction

abstract:
  The separate and combined influences of the spin-orbit and electron-electron
interactions on the electron magnetization in quantum rings have been studied
theoretically on the basis of the spin-density-functional theory and the
Kohn-Sham equation used for the calculation of electron states in
two-dimensional parabolic quantum rings containing from two to six electrons.
The magnetization of electrons in a quantum ring is calculated at zero
temperature. The revealed abrupt changes in the ring magnetization are
associated with the crossing of electron states that occurs if the spin-orbit
and/or electron-electron interactions are taken into consideration.


title:
Quasi Regular Semilattice and Association Schemes in Singular Linear
  Space

abstract:
  Let \mathbb{F}_q^{n+l} denote the (n+l)-dimensional singular linear space
over a finite field \mathbb{F}_q. For a fixed integer m\leq\min\{n,l\}, denote
by \mathcal{L}^m_o(\mathbb{F}_q^{n+l}) the set of all subspaces of type
(t,t_1), where t_1\leq t\leq m. Partially ordered by ordinary inclusion, one
family of quasi regular semilattices is obtained. Moreover, we obtain a
association schemes and discuss the bound of a M-clique.


title:
HST hot Jupiter transmission spectral survey: evidence for aerosols and
  lack of TiO in the atmosphere of WASP-12b

abstract:
  We present HST optical transmission spectra of the transiting hot Jupiter
WASP-12b, taken with the STIS instrument. From the transmission spectra, we are
able to decisively rule out prominent absorption by TiO in the exoplanet's
atmosphere. Strong pressure-broadened Na and K absorption signatures are also
excluded, as are significant metal-hydride features. We compare our combined
broadband spectrum to a wide variety of existing aerosol-free atmospheric
models, though none are satisfactory fits. However, we do find that the full
transmission spectrum can be described by models which include significant
opacity from aerosols: including Rayleigh scattering, Mie scattering, tholin
haze, and settling dust profiles. The transmission spectrum follows an
effective extinction cross section with a power-law of index alpha, with the
slope of the transmission spectrum constraining the quantity alphaT =
-3528+/-660 K, where T is the atmospheric temperature. Rayleigh scattering
(alpha=-4) is among the best fitting models, though requires low terminator
temperatures near 900 K. Sub-micron size aerosol particles can provide equally
good fits to the entire transmission spectrum for a wide range of temperatures,
and we explore corundum as a plausible dust aerosol. The presence of
atmospheric aerosols also helps to explain the modestly bright albedo implied
by Spitzer observations, as well as the near black body nature of the emission
spectrum. Ti-bearing condensates on the cooler night-side is the most natural
explanation for the overall lack of TiO signatures in WASP-12b, indicating the
day/night cold-trap is an important effect for very hot Jupiters. These finding
indicate that aerosols can play a significant atmospheric role for the entire
wide range of hot-Jupiter atmospheres, potentially affecting their overall
spectrum and energy balance.(abridged)


title: Near-Field Passive RFID Communication: Channel Model and Code Design

abstract:
  This paper discusses a new channel model and code design for the
reader-to-tag channel in near-field passive radio frequency identification
(RFID) systems using inductive coupling as a power transfer mechanism. If the
receiver resynchronizes its internal clock each time a bit is detected, the
bit-shift channel used previously in the literature to model the reader-to-tag
channel needs to be modified. In particular, we propose a discretized Gaussian
shift channel as a new channel model in this scenario. We introduce the concept
of quantifiable error avoidance, which is much simpler than error correction.
The capacity is computed numerically, and we also design some new simple codes
for error avoidance on this channel model based on insights gained from the
capacity calculations. Finally, some simulation results are presented to
compare the proposed codes to the Manchester code and two previously proposed
codes for the bit-shift channel model.


title: Beam-Plasma Instability and Fast Particles: the Lynden-Bell Approach

abstract:
  The beam-plasma instability, i.e. the response of the plasma bulk to the
injection of supra thermal charged-particle beams, results to be appropriately
characterized by a long-range interaction system. This physical system hosts a
number of very interesting phenomena and, in particular, the emergence of
long-lived quasi-stationary states. We characterize the self-consistent
distribution functions of such out-of-equilibrium states by means of the
Lynden-Bell's theory. The prediction of this theory, based on the statistical
mechanics of the Vlasov equation, are checked against the outcomes of numerical
simulations of the discrete system. Moreover, a phenomenological study of the
effective resonance band for the system response is also addressed. A threshold
value has been found in the initial spread of beam-particle momenta. This
threshold allows to discriminate between the resonant and non-resonant regimes.
The analysis of the thermalization of a few percents of the beam population
characterized by large initial momenta (with respect to the main part of the
beam itself) is also performed and it confirms and deepens the understanding of
the physical meaning of the mentioned threshold.


title: Sequential Change Detection in the Presence of Unknown Parameters

abstract:
  It is commonly required to detect change points in sequences of random
variables. In the most difficult setting of this problem, change detection must
be performed sequentially with new observations being constantly received over
time. Further, the parameters of both the pre- and post- change distributions
may be unknown. In a recent paper by Hawkins and Zamba (2005), the sequential
generalised likelihood ratio test was introduced for detecting changes in this
context, under the assumption that the observations follow a Gaussian
distribution. However, we show that the asymptotic approximation used in their
test statistic leads to it being conservative even when a large numbers of
observations is available. We propose an improved procedure which is more
efficient, in the sense of detecting changes faster, in all situations. We also
show that similar issues arise in other parametric change detection contexts,
which we illustrate by introducing a novel monitoring procedure for sequences
of Exponentially distributed random variable, which is an important topic in
time-to-failure modelling.


title: Factor groups, semidirect product and quantum chemistry

abstract:
  In this paper we prove some general theorems about representations of finite
groups arising from the inner semidirect product of groups. We show how these
results can be used for standard applications of group theory in quantum
chemistry through the orthogonality relations for the characters of irreducible
representations. In this context, conditions for transitions between energy
levels, projection operators and basis functions were determined. This approach
applies to composite systems and it is illustrated by the dihedral group
related to glycolate oxidase enzyme.


title: Asymptotic Flatness and Quantum Geometry

abstract:
  We construct a canonical quantization of the two dimensional theory of a
parametrized scalar field on noncompact spatial slices. The kinematics is built
upon generalized charge-network states which are labelled by smooth embedding
spacetimes, unlike the standard basis states carrying only discrete labels. The
resulting quantum geometry corresponds to a nondegenerate vacuum metric, which
allows a consistent realization of the asymptotic conditions on the canonical
fields. Although the quantum counterpart of the classical symmetry group of
conformal isometries consists only of continuous global translations, Lorentz
invariance can still be recovered in an effective sense. The quantum spacetime
as characterized by a gauge invariant state is shown to be made up of discrete
strips at the interior, and smooth at asymptotia. The analysis here is expected
to be particularly relevant for a canonical quantization of asymptotically flat
gravity based on generalized spin-network states labelled by smooth geometries.


title:
The Lax integrability of a two-component hierarchy of the Burgers type
  dynamical systems within asymptotic and differential-algebraic approaches

abstract:
  The Lax type integrability of a two-component polynomial Burgers type
dynamical system within a differential-algebraic approach is studied, its
linear adjoint matrix Lax representation is constructed. A related recursion
operator and infnite hierarchy of Lax integrable nonlinear dynamical systems of
the Burgers-Korteweg-de Vries type are derived by means of the
gradient-holonomic technique, the corresponding Lax type representations are
presented.


title: Implementation of a Quantum Metamaterial

abstract:
  Manipulating the propagation of electromagnetic waves through sub-wavelength
sized artificial structures is the core function of metamaterials. Resonant
structures, such as split ring resonators, play the role of artificial "atoms"
and shape the magnetic response. Superconducting metamaterials moved into the
spotlight for their very low ohmic losses and the possibility to tune their
resonance frequency by exploiting the Josephson inductance. Moreover, the
nonlinear nature of the Josephson inductance enables the fabrication of truly
artificial atoms. Arrays of such superconducting quantum two-level systems
(qubits) can be used for the implementation of a quantum metamaterial. Here, we
perform an experiment in which 20 superconducting flux qubits are embedded into
a single microwave resonator. The phase of the signal transmitted through the
resonator reveals the collective resonant coupling of up to 8 qubits. Quantum
circuits of many artificial atoms based on this proof-of-principle experiment
offer a wide range of prospects, from detecting single microwave photons to
phase switching, quantum birefringence and superradiant phase transitions.


title: Observation of an Effective Magnetic field for Light

abstract:
  Photons are neutral particles that do not interact directly with a magnetic
field. However, recent theoretical work has shown that an effective magnetic
field for photons can exist if the phase of light would change with its
propagating direction. This direction-dependent phase indicates the presence of
an effective magnetic field as shown for electrons experimentally in the
Aharonov-Bohm experiment. Here we replicate this experiment using photons. In
order to create this effective magnetic field, we construct an on-chip
silicon-based Ramsey-type interferometer. This interferometer has been
traditionally used to probe the phase of atomic states, and here we apply it to
probe the phase of photonic states. We experimentally observe a phase change,
i.e. an effective magnetic field flux from 0 to 2pi. In an Aharonov-Bohm
configuration for electrons, considering the device geometry, this flux
corresponds to an effective magnetic field of 0.2 Gauss.


title: Non-Markovianity of colored noisy channels

abstract:
  We address the non-Markovian character of quantum maps describing the
interaction of a qubit with a random classical field. In particular, we
evaluate trace- and capacity-based non-Markovianity measures for two relevant
classes of environments showing non-Gaussian fluctuations, described
respectively by random telegraph noise and colored noise with spectra of the
the form $1/f^\alpha$. We analyze the dynamics of both the trace distance and
the quantum capacity, and show that the behavior of non-Markovianity based on
both measures is qualitatively similar. Our results show that environments with
a spectrum that contains a relevant low-frequency contribution are generally
non-Markovian. We also find that the non-Markovianity of colored environments
decreases when the number of fluctuators realizing the environment increases.


title:
A $sqrt{n}$ estimate for measures of hyperplane sections of convex
  bodies

abstract:
  We prove an estimate for arbitrary measure of sections of convex bodies. The
proof is based on a stability result for intersection bodies.


title: On the nature of Mersenne fluctuations

abstract:
  In Part I, crotons are introduced, multifaceted pre-geometric objects that
occur both as labels encoded on the boundary of a "volume" and as complementary
aspects of geometric fluctuations within that volume. If you think of crotons
as linear combinations, then the scalars used are croton base numbers. Croton
base numbers can be combined to form the amplitudes and phases of Mersenne
fluctuations which, in turn, form qphyla. Volume normally requires space or
space-time as a prerequisite; in a pregeometric setting, however, "volume" is
represented by a qphyletic assembly. Various stages of pre-geometric
refinement, expressed through the aspects crotonic amplitude or phase, combine
to eventually form and/or dissolve sphere-packed chunks of Euclidean space. A
time-like crotonic refinement is a rough analog of temporal resolution in
tenacious time, whereas space-like crotonic refinement is analogous to spatial
resolution in sustained space. The analogy suggests a conceptual link between
the ever-expanding scope of Mersenne fluctuations and the creation and lifetime
patterns of massive elementary particles. A three-stage process of ideation,
organization and intraworldly action is introduced to back this up. In Part II,
the intrawordly aspect is analyzed first, including our preon model of
subnuclear structure, and the organizer aspect thereafter, based on three types
of Mersenne numbers, $M_{\textrm{reg}}$, $M_{5/8}$, $M_{9/8}$, and two formal
principles: juxtaposition $x$ vs. $\! x\!\pm\!1(2)$ and the interordinal
application of functional
$1\!\divideontimes(f^{(a)}\!\circ(f^{(b)}\!\divideontimes f^{(c)}))$.


title: Probing Higgs couplings with high p_T Higgs production

abstract:
  Possible extensions of the Standard Model predict modifications of the Higgs
couplings to gluons and to the SM top quark. The values of these two couplings
can, in general, be independent. We discuss a way to measure these interactions
by studying the Higgs production at high p_T within an effective field theory
formalism. We also propose an observable r_\pm with reduced theoretical errors
and suggest its experimental interpretation.


title: Fast Convergence of Regress-Later Estimates in Least Squares Monte Carlo

abstract:
  Many problems in financial engineering involve the estimation of unknown
conditional expectations across a time interval. Often Least Squares Monte
Carlo techniques are used for the estimation. One method that can be combined
with Least Squares Monte Carlo is the "Regress-Later" method. Unlike
conventional methods where the value function is regressed on a set of basis
functions valued at the beginning of the interval, the "Regress-Later" method
regresses the value function on a set of basis functions valued at the end of
the interval. The conditional expectation across the interval is then computed
exactly for each basis function. We provide sufficient conditions under which
we derive the convergence rate of Regress-Later estimators. Importantly, our
results hold on non-compact sets. We show that the Regress-Later method is
capable of converging significantly faster than conventional methods and
provide an explicit example. Achieving faster convergence speed provides a
strong motivation for using Regress-Later methods in estimating conditional
expectations across time.