title:
Flashing coherently rotating carbon sticks in $^{24}$Mg+$^{24}$Mg
  collision

abstract:
  The present discussion rises a number of the questions. For example, is
rotational coherence of large molecules necessarily destroyed in the
conventionally statistical limit of structureless non-selective continuum (for
fixed total spin and parity values) under the conditions of complete
intramolecular energy redistribution and vibrational dephasing in the regime of
strong ro-vibrational coupling? For the slow cross-symmetry phase relaxation,
quantum coherent superpositions of a large number of complex configurations
with, e.g., many different total angular momenta produce image of a rotation of
macroscopic object with classically fixed (single) total angular momentum.
Suppose that the quantum coherent superpositions involving a very large number
of different good quantum numbers play a role, in a hidden form, in a formation
of macroscopic world. Then why these quantum superpositions are so stable
against quick aging/decay of ordered complex structures preventing or slowing
down tendencies towards uniform occupation of the available phase space as
prescribed by the random matrix theory? And what kind of complex macroscopic
phenomena may reveal traces of partially coherent quantum superpositions
involving a huge number of quantum-mechanically different integrals of motion
behind of what is referred to as conservation laws in classical physics
employed for the description of the macroscopic world?


title:
Identifying the nature of interaction between LiBH4 and two-dimensional
  substrates: DFT study with van der Waals correction

abstract:
  Addressing the nature of interaction at the LiBH4-carbon interface is the key
to unveiling mechanism for the carbon-facilitated desorption of lithium
borohydride (LiBH4). Density functional theory calculations, taking into
account the long range dispersion forces, have been performed to explore the
interaction between LiBH4, in the form of either a monomer unit or a
crystalline bulk, and two-dimensional (2D) substrate, represented by graphene
and hexagonal boron nitride. At the monomer-2D contact, the permanent dipole of
LiBH4 induces polarization of the pi electrons of the 2D, and the resultant
permanent dipole-induced dipole attraction becomes the main source of binding.
At the bulk-2D interface van der Waals attraction dominates the interfacial
binding rather than the dipole-diploe attraction. The absolute values of the
calculated interface energy match closely with the surface energy of pristine
(001) LiBH4, hinting that the energy released by the formation of the interface
has enough magnitude to overcome the surface energy of LiBH4.


title:
Negative Sobolev Spaces and the Two-species Vlasov-Maxwell-Landau System
  in the Whole Space

abstract:
  A global solvability result of the Cauchy problem of the two-species
Vlasov-Maxwell-Landau system near a given global Maxwellian is established by
employing an approach different than that of [5]. Compared with that of [5],
the minimal regularity index and the smallness assumptions we imposed on the
initial data are weaker. Our analysis does not rely on the decay of the
corresponding linearized system and the Duhamel principle and thus it can be
used to treat the one-species Vlasov-Maxwell-Landau system for the case of
$\gamma>-3$ and the one-species Vlasov-Maxwell-Boltzmann system for the case of
$-1<\gamma\leq 1$ to deduce the global existence results together with the
corresponding temporal decay estimates.


title:
On a bound of Heath-Brown for Dirichlet $L$-functions on the critical
  line

abstract:
  Let $\chi$ a primitive character$\pmod q$ and consider the Dirichlet
$L$-function $$L(s,\chi)=\sum_{n=1}^{\infty}\frac{\chi(n)}{n^s}.$$ We give a
new proof of an upper bound of Heath-Brown for $|L(s,\chi)|$ on the critical
line $s=1/2+it$


title:
Contextually learnt detection of unusual motion-based behaviour in
  crowded public spaces

abstract:
  In this paper we are interested in analyzing behaviour in crowded public
places at the level of holistic motion. Our aim is to learn, without user
input, strong scene priors or labelled data, the scope of "normal behaviour"
for a particular scene and thus alert to novelty in unseen footage. The first
contribution is a low-level motion model based on what we term tracklet
primitives, which are scene-specific elementary motions. We propose a
clustering-based algorithm for tracklet estimation from local approximations to
tracks of appearance features. This is followed by two methods for motion
novelty inference from tracklet primitives: (a) we describe an approach based
on a non-hierarchial ensemble of Markov chains as a means of capturing
behavioural characteristics at different scales, and (b) a more flexible
alternative which exhibits a higher generalizing power by accounting for
constraints introduced by intentionality and goal-oriented planning of human
motion in a particular scene. Evaluated on a 2h long video of a busy city
marketplace, both algorithms are shown to be successful at inferring unusual
behaviour, the latter model achieving better performance for novelties at a
larger spatial scale.


title: Multiple-object tracking in cluttered and crowded public spaces

abstract:
  This paper addresses the problem of tracking moving objects of variable
appearance in challenging scenes rich with features and texture. Reliable
tracking is of pivotal importance in surveillance applications. It is made
particularly difficult by the nature of objects encountered in such scenes:
these too change in appearance and scale, and are often articulated (e.g.
humans). We propose a method which uses fast motion detection and segmentation
as a constraint for both building appearance models and their robust
propagation (matching) in time. The appearance model is based on sets of local
appearances automatically clustered using spatio-kinetic similarity, and is
updated with each new appearance seen. This integration of all seen appearances
of a tracked object makes it extremely resilient to errors caused by occlusion
and the lack of permanence of due to low data quality, appearance change or
background clutter. These theoretical strengths of our algorithm are
empirically demonstrated on two hour long video footage of a busy city
marketplace.


title:
Peeking Inside the Black Box: Visualizing Statistical Learning with
  Plots of Individual Conditional Expectation

abstract:
  This article presents Individual Conditional Expectation (ICE) plots, a tool
for visualizing the model estimated by any supervised learning algorithm.
Classical partial dependence plots (PDPs) help visualize the average partial
relationship between the predicted response and one or more features. In the
presence of substantial interaction effects, the partial response relationship
can be heterogeneous. Thus, an average curve, such as the PDP, can obfuscate
the complexity of the modeled relationship. Accordingly, ICE plots refine the
partial dependence plot by graphing the functional relationship between the
predicted response and the feature for individual observations. Specifically,
ICE plots highlight the variation in the fitted values across the range of a
covariate, suggesting where and to what extent heterogeneities might exist. In
addition to providing a plotting suite for exploratory analysis, we include a
visual test for additive structure in the data generating model. Through
simulated examples and real data sets, we demonstrate how ICE plots can shed
light on estimated models in ways PDPs cannot. Procedures outlined are
available in the R package ICEbox.


title:
N=1 Supersymmetric Non-Abelian Compensator Mechanism for Extra Vector
  Multiplet

abstract:
  We present a variant formulation of N=1 supersymmetric compensator mechanism
for an arbitrary non-Abelian group in four dimensions. This formulation
resembles our previous variant supersymmetric compensator mechanism in 4D. Our
field content consists of the three multiplets: (i) A Non-Abelian Yang-Mills
multiplet (A_\mu^I, \lambda^I, C_{\mu\nu\rho}^I), (ii) a tensor multiplet
(B_{\mu\nu}^I, \chi^I, \varphi^I) and an extra vector multiplet (K_\mu^I,
\rho^I, C_{\mu\nu\rho}^I) with the index I for the adjoint representation of a
non-Abelian gauge group. The C_{\mu\nu\rho}^I is originally an auxiliary field
dual to the conventional auxiliary field D^I for the extra vector multiplet.
The vector K_\mu^I and the tensor C_{\mu\nu\rho}^I get massive, after absorbing
respectively the scalar \varphi^I and the tensor B_{\mu\nu}^I. The superpartner
fermion \rho^I acquires a Dirac mass shared with \chi^I. We fix all non-trivial
cubic interactions in the total lagrangian, all quadratic terms in
supersymmetry transformations, and all quadratic interactions in field
equations. The action invariance and the super-covariance of all field
equations are confirmed up to the corresponding orders.


title:
Study of diphoton decays of the lightest scalar Higgs boson in the
  Next-to-Minimal Supersymmetric Standard Model

abstract:
  The CMS and ATLAS experiments at the LHC have announced the discovery of a
Higgs boson with mass at approximately 125 $GeV/c^{2}$ in the search for the
Standard Model Higgs boson via notably the $\gamma\gamma$ and $ZZ$ to four
leptons final states. Considering the recent results on the Higgs boson
searches from the LHC, we study the lightest scalar Higgs boson $h_{1}$ in the
Next-to-Minimal Supersymmetric Standard Model by restricting the
next-to-lightest scalar Higgs boson $h_{2}$ to be the observed 125 $GeV/c^{2}$
state. We perform a scan over the relevant NMSSM parameter space that is
favoured by low fine-tuning considerations. Moreover, we also take the
experimental constraints from direct searches, $B$-physics observables, relic
density and anomalous magnetic moment of the muon measurements as well as the
theoretical considerations into account in our specific scan. We find that the
signal rate in the two-photon final state for the NMSSM Higgs boson $h_{1}$
with the mass range from approximately 80 $GeV/c^{2}$ to 122 $GeV/c^{2}$ can be
enhanced by a factor up to 3.5, when the Higgs boson $h_{2}$ is required to be
compatible with the excess from latest LHC results. This motivates the
extension of the search at the LHC for the Higgs boson $h_{1}$ in the diphoton
final state down to masses of 80 $GeV/c^{2}$ or lower, in particular with the
upcoming proton-proton collision data to be taken at center-of-mass energies of
13-14 $TeV$.


title:
Optimal Selection of Spectrum Sensing Duration for an Energy Harvesting
  Cognitive Radio

abstract:
  In this paper, we consider a time-slotted cognitive radio (CR) setting with
buffered and energy harvesting primary and CR users. At the beginning of each
time slot, the CR user probabilistically chooses the spectrum sensing duration
from a predefined set. If the primary user (PU) is sensed to be inactive, the
CR user accesses the channel immediately. The CR user optimizes the sensing
duration probabilities in order to maximize its mean data service rate with
constraints on the stability of the primary and cognitive queues. The
optimization problem is split into two subproblems. The first is a
linear-fractional program, and the other is a linear program. Both subproblems
can be solved efficiently.


title:
Innermost Stable Circular Orbits and Epicyclic Frequencies Around a
  Magnetized Neutron Star

abstract:
  A full-relativistic approach is used to compute the radius of the innermost
stable circular orbit (ISCO), the Keplerian, frame-dragging, precession and
oscillation frequencies of the radial and vertical motions of neutral test
particles orbiting the equatorial plane of a magnetized neutron star. The
space-time around the star is modelled by the six parametric solution derived
by Pachon et al. It is shown that the inclusion of an intense magnetic field,
such as the one of a neutron star, have non-negligible effects on the above
physical quantities, and therefore, its inclusion is necessary in order to
obtain a more accurate and realistic description of the physical processes
occurring in the neighbourhood of this kind of objects such as the dynamics of
accretion disk. The results discussed here also suggest that the consideration
of strong magnetic fields may introduce non-negligible corrections in, e.g.,
the relativistic precession model and therefore on the predictions made on the
mass of neutron stars.


title: ProtoMD: A Prototyping Toolkit for Multiscale Molecular Dynamics

abstract:
  ProtoMD is a toolkit that facilitates the development of algorithms for
multiscale molecular dynamics (MD) simulations. It is designed for multiscale
methods which capture the dynamic transfer of information across multiple
spatial scales, such as the atomic to the mesoscopic scale, via coevolving
microscopic and coarse-grained (CG) variables. ProtoMD can be also be used to
calibrate parameters needed in traditional CG-MD methods. The toolkit
integrates `GROMACS wrapper' to initiate MD simulations, and `MDAnalysis' to
analyze and manipulate trajectory files. It facilitates experimentation with a
spectrum of coarse-grained variables, prototyping rare events (such as chemical
reactions), or simulating nanocharacterization experiments such as terahertz
spectroscopy, AFM, nanopore, and time-of-flight mass spectroscopy. ProtoMD is
written in python and is freely available under the GNU General Public License
from github.com/CTCNano/proto_md.


title:
Superconductivity in 1111-type CaFeAsF1-xHx induced by selective
  hydrogen elimination

abstract:
  The difference in thermal stability of F- and H- in 1111-type iron based
superconductors, allows selective hydrogen elimination from non-superconductive
CaFeAsF0.8H0.2 by thermal annealing. The analyzed chemical composition of the
resulting samples indicates that incorporated hydrogen was selectively
eliminated by thermal annealing at 553 K for 72 hours. The resulting
hydrogen-eliminated sample shows bulk superconductivity with Tc = 29 K. This
technique may be used for indirect electron doping for AeFeAeF (Ae;
alkali-earth metal) iron based superconductor described by CaFeAsF1-xHx =>
CaFeAsF1-x + xe- + 1/2xH2.


title: Limits on violations of Lorentz Symmetry from Gravity Probe B

abstract:
  Generic violations of Lorentz symmetry can be described by an effective field
theory framework that contains both general relativity and the standard model
of particle physics called the Standard-Model Extension (SME). We obtain new
constraints on the gravitational sector of the SME using recently published
final results from Gravity Probe B. These include for the first time an upper
limit at the 10^(-3) level on the time-time component of the new tensor field
responsible for inducing local Lorentz violation in the theory, and an
independent limit at the 10^(-7) level on a combination of components of this
tensor field.


title:
Structural Analysis and Superconducting Properties of F-Substituted
  NdOBiS2 Single Crystals

abstract:
  F-substituted NdOBiS2 superconducting single crystals were grown using
CsCl/KCl flux. This is the first example of the single-crystal growth of a
BiS2-based superconductor. The obtained single crystals had a plate-like shape
with a size of 1-2 mm and a well-developed ab-plane. The crystal structure of
the grown crystals was determined by single-crystal X-ray diffraction analysis
to be the tetragonal space group P4/nmm (#129) with a = 3.996(3) A and c =
13.464(6) A. The chemical formula of the grown crystals was approximately
Nd0.98(0.06)O0.7(0.1)F0.3(0.1)Bi0.98(0.04)S2, and Cs, K, and Cl were not
detected in the grown crystals by electron probe microanalysis. The grown
crystals had a critical temperature of approximately 5 K. The superconducting
anisotropy of the single crystals was estimated to be about 30 from the
effective mass model and the upper critical field.


title: Preperiodic points for quadratic polynomials over quadratic fields

abstract:
  To each quadratic number field $K$ and each quadratic polynomial $f$ with
$K$-coefficients, one can associate a finite directed graph $G(f,K)$ whose
vertices are the $K$-rational preperiodic points for $f$, and whose edges
reflect the action of $f$ on these points. This paper has two main goals. (1)
For an abstract directed graph $G$, classify the pairs $(K,f)$ such that the
isomorphism class of $G$ is realized by $G(f,K)$. We succeed completely for
many graphs $G$ by applying a variety of dynamical and Diophantine techniques.
(2) Give a complete description of the set of isomorphism classes of graphs
that can be realized by some $G(f,K)$. A conjecture of Morton and Silverman
implies that this set is finite. Based on our theoretical considerations and a
wealth of empirical evidence derived from an algorithm that is developed in
this paper, we speculate on a complete list of isomorphism classes of graphs
that arise from quadratic polynomials over quadratic fields.


title:
A Bregman projection method for approximating fixed points of
  quasi-Bregman nonexpansive mappings

abstract:
  We introduce an abstract algorithm that aims to find the Bregman projection
onto a closed convex set. As an application, the asymptotic behaviour of an
iterative method for finding a fixed point of a quasi Bregman nonexpansive
mapping with the fixed-point closedness property is analyzed. We also show that
our result is applicable to Bregman subgradient projectors.


title: Explicit Chow-Lefschetz Decomposition for Kummer manifolds

abstract:
  Let X be the quotient of a smooth projective variety over a field by a finite
group action (in which case we say X is pseudo-smooth), such that the
singularities of X are isolated k-rational points. Let Y be obtained by blowing
up these points on X. Assume further that
  Y is pseudo-smooth, and that the components of the exceptional divisor are
projective spaces. Then, without invoking the theory of finite-dimensional
motives or assuming any of the standard conjectures, we show that a
Chow-Kunneth decomposition on either X or Y gives rise, by means of an explicit
construction, to a Chow-Kunneth decomposition on the other. We use these
constructions to show that various properties (among them, Conjectures of
Murre, and being of Lefschetz type) hold for X if and only if they hold for Y.
The main examples of interest to us are Kummer manifolds. We give several
further applications of our construction to this particular class of examples.


title:
Jacobi Forms of Higher Index and Paramodular Groups in N=2, D=4
  Compactifications of String Theory

abstract:
  We associate a Jacobi form over a rank s lattice to N=2, D=4 heterotic string
compactifications which have s Wilson lines at a generic point in the vector
multiplet moduli space. Jacobi forms of index m=1 and m=2 have appeared earlier
in the context of threshold corrections to heterotic string couplings. We
emphasize that higher index Jacobi forms as well as Jacobi forms of several
variables over more generic even lattices also appear and construct models in
which they arise. In particular, we construct an orbifold model which can be
connected to models that give index m=3, 4 or 5 Jacobi forms through the
Higgsing process. Constraints from being a Jacobi form are then employed to get
threshold corrections using only partial information on the spectrum. We apply
this procedure for index m=3, 4 or 5 Jacobi form examples and also for Jacobi
forms over A_2 and A_3 root lattices. Examples with a single Wilson line are
examined in detail and we display the relation of Siegel forms over a
paramodular group \Gamma_m to these models, where \Gamma_m is associated with
the T-duality group of the models we study. Finally, results on the heterotic
string side are used to clarify the linear mapping of vector multiplet moduli
to Type IIA duals without using the one-loop cubic part of the prepotential on
the Type II side, and also to give predictions for the geometry of the dual
Calabi-Yau manifolds.


title: Error matrices in quantum process tomography

abstract:
  We discuss characterization of experimental quantum gates by the error
matrix, which is similar to the standard process matrix $\chi$ in the Pauli
basis, except the desired unitary operation is factored out, by formally
placing it either before or after the error process. The error matrix has only
one large element, which is equal to the process fidelity, while other elements
are small and indicate imperfections. The imaginary parts of the elements along
the left column and/or top row directly indicate the unitary imperfection and
can be used to find the needed correction. We discuss a relatively simple way
to calculate the error matrix for a composition of quantum gates. Similarly, it
is rather straightforward to find the first-order contribution to the error
matrix due to the Lindblad-form decoherence. We also discuss a way to identify
and subtract the tomography procedure errors due to imperfect state preparation
and measurement. In appendices we consider several simple examples of the
process tomography and also discuss an intuitive physical interpretation of the
Lindblad-form decoherence.


title:
Crossed products of $L^p$ operator algebras and the K-theory of Cuntz
  algebras on $L^p$ spaces

abstract:
  For $p \in [1, \infty),$ we define and study full and reduced crossed
products of algebras of operators on $\sigma$-finite $L^p$ spaces by isometric
actions of second countable locally compact groups. We give universal
properties for both crossed products. When the group is abelian, we prove the
existence of a dual action on the full and reduced $L^p$ operator crossed
products. When the group is discrete, we construct a conditional expectation to
the original algebra which is faithful in a suitable sense. For a free action
of a discrete group on a compact metric space $X,$ we identify all traces on
the reduced $L^p$ operator crossed product, and if the action is also minimal
we show that the reduced $L^p$ operator crossed product is simple. We prove
that the full and reduced $L^p$ operator crossed products of an amenable $L^p$
operator algebra by a discrete amenable group are again amenable. We prove a
Pimsner-Voiculescu exact sequence for the K-theory of reduced $L^p$ operator
crossed products by ${\mathbb{Z}}.$ We show that the $L^p$ analogs
${\mathcal{O}}_d^p$ of the Cuntz algebras ${\mathcal{O}}_d$ are stably
isomorphic to reduced $L^p$ operator crossed products of stabilized $L^p$ UHF
algebra by ${\mathbb{Z}},$ and show that $K_0 ({\mathcal{O}}_d^p) \cong
{\mathbb{Z}} / (d - 1) {\mathbb{Z}}$ and $K_1 ({\mathcal{O}}_d^p) = 0.$


title: Spin Gap in Heavy Fermion UBe$_{13}$

abstract:
  Muon spin rotation ($\mu^+$SR) experiments have been carried out in the heavy
fermion compound UBe$_{13}$ in the temperature range from 0.025 K to 300 K and
in magnetic fields up to 7 T, supported by resistivity and magnetization
measurements. The $\mu^+$SR spectra are characteristic of formation of a spin
polaron which persists to the lowest temperature. A gap in the spin excitation
spectrum of f-electrons opens up at about 180 K, consistent with anomalies
discovered in resistivity, heat capacity, NMR and optical conductivity
measurements of UBe$_{13}$.


title: Symplectic intersections and invariant measures

abstract:
  We detect, by using symplectic topology, invariant measures with large
rotation vectors for a class of Hamiltonian flows.


title: Dynamics of Three Non-co-rotating Vortices in Bose-Einstein Condensates

abstract:
  In this work we use standard Hamiltonian-system techniques in order to study
the dynamics of three vortices with alternating charges in a confined
Bose-Einstein condensate. In addition to being motivated by recent experiments,
this system offers a natural vehicle for the exploration of the transition of
the vortex dynamics from ordered to progressively chaotic behavior. In
particular, it possesses two integrals of motion, the {\it energy} (which is
expressed through the Hamiltonian $H$) and the {\it angular momentum} $L$ of
the system. By using the integral of the angular momentum, we reduce the system
to a two degree-of-freedom one with $L$ as a parameter and reveal the topology
of the phase space through the method of Poincar\'e surfaces of section.
  We categorize the various motions that appear in the different regions of the
sections and we study the major bifurcations that occur to the families of
periodic motions of the system. Finally, we correspond the orbits on the
surfaces of section to the real space motion of the vortices in the plane.


title: Doping-less Tunnel Field Effect Transistor: Design and Investigation

abstract:
  Using calibrated simulations, we report a detailed study of the doping-less
tunnel field effect transistor (TFET) on a thin intrinsic silicon film using
charge plasma concept. Without the need for any doping, the source and drain
regions are formed using the charge plasma concept by choosing appropriate work
functions for the source and drain metal electrodes. Our results show that the
performance of the doping-less TFET is similar to that of a corresponding doped
TFET. The doping-less TFET is expected to be free from problems associated with
random dopant fluctuations. Further, fabrication of doping-less TFET does not
require high-temperature doping/annealing processes and therefore, cuts down
the thermal budget opening up the possibilities for fabricating TFETs on single
crystal silicon-on-glass substrates formed by wafer scale epitaxial transfer.


title: Gamma-ray Emission from Millisecond Pulsars - An Outergap Perspective

abstract:
  In this review paper we explain the following gamma-ray emission features
from the millisecond pulsars. (1)Why is the dipolar field of millisecond
pulsars so weak but the magnetic pair creation process may still be able to
control the size of the outergap? (2)A sub-GeV pulse component could occur in
the vicinity of the radio pulse of millisecond pulsars. (3)Orbital modulated
gamma-rays should exist in the black widow systems for large viewing angle.


title:
Structural Tristability and Deep Dirac States in Bilayer Silicene on
  Ag(111) Surfaces

abstract:
  We report on total-energy electronic-structure calculations in the
density-functional theory performed for both monolayer and bilayer silicene on
Ag(111) surfaces. The rt3 x rt3 structure observed experimentally and argued to
be the monolayer silicene in the past [Chen et al., Phys. Rev. Lett. 110,
085504 (2013)] is identified as the bilayer silicene on the Ag(111) surface.
The identification is based on our accurate density-functional calculations in
which three approximations, the local density approximation, the
generalized-gradient approximation, and the van-der-Waals-density-functional
approximation, to the exchange-correlation energy have been carefully examined.
We find that the structural tristability exists for the rt3 x rt3 bilayer
silicene. The calculated energy barriers among the three stable structures are
in the range of 7 - 9 meV per Si atom, indicating possible flip-flop motions
among the three. We have found that the flip-flop motion between the two of the
three structures produces the honeycomb structure in the STM images, whereas
the motion among the three does the 1 x 1 structure. We have found that the
electron states which effectively follow Dirac equation in the freestanding
silicene couple with the substrate Ag orbitals due to the bond formation, and
shift downwards deep in the valence bands. This feature is common to all the
stable or metastable silicene layer on the Ag(111) substrate.


title:
Cosmological investigations of (extended) nonlinear massive gravity
  schemes with non-minimal coupling

abstract:
  In this paper we investigate the case of non-minimal coupling in the
(extended) nonlinear massive gravity theories. We first consider massive
gravity in the Brans-Dicke background such that the graviton mass is replaced
by $A^2(\sigma)m$ where $\sigma$ is the Brans-Dicke field and $A(\sigma)$ is
conformal coupling and show that there is no viable thermal history of the
universe in this case. We then invoke a cubic galileon term as nonlinear
completion of the $\sigma$ Lagrangian and show that there is a stable de Sitter
solution in this case. However, the de Sitter is blocked by the matter phase
which is also a simultaneous attractor of the dynamics. The de Sitter phase
can, however, be realized by invoking unnatural fine tunings. We next
investigate cosmology of quasi-dilaton nonlinear massive gravity with
non-minimal coupling. As a generic feature of the non-minimal coupling, we show
that the model exhibits a transient phantom phase which is otherwise
impossible. While performing the observational data analysis on the models, we
find that a small value of coupling constant is allowed for quasi-dilaton
nonlinear massive gravity. For both the cases under consideration, it is
observed that we have an effective pressure of matter which comes from the
constraint equation. For mass-varying nonlinear massive gravity in the
Brans-Dicke background, the effective pressure of matter is non zero which
affects the evolution of the Hubble parameter thereby spoiling consistency of
the model with data. As for, quasi-dilaton nonlinear massive gravity, the
effective pressure of matter can be kept around zero by controlling the
coupling constant, the model is shown to be fit well with observations.


title: Uniqueness of Stable Processes with Drift

abstract:
  Suppose that $d\geq1$ and $\alpha\in (1, 2)$. Let $Y$ be a rotationally
symmetric $\alpha$-stable process on $\R^d$ and $b$ a $\R^d$-valued measurable
function on $\R^d$ belonging to a certain Kato class of $Y$. We show that $\rd
X^b_t=\rd Y_t+b(X^b_t)\rd t$ with $X^b_0=x$ has a unique weak solution for
every $x\in \R^d$. Let $\sL^b=-(-\Delta)^{\alpha/2} + b \cdot \nabla$, which is
the infinitesimal generator of $X^b$. Denote by $C^\infty_c(\R^d)$ the space of
smooth functions on $\R^d$ with compact support. We further show that the
martingale problem for $(\sL^b, C^\infty_c(\R^d))$ has a unique solution for
each initial value $x\in \R^d$.


title:
Stratified Graphical Models - Context-Specific Independence in Graphical
  Models

abstract:
  Theory of graphical models has matured over more than three decades to
provide the backbone for several classes of models that are used in a myriad of
applications such as genetic mapping of diseases, credit risk evaluation,
reliability and computer security, etc. Despite of their generic applicability
and wide adoptance, the constraints imposed by undirected graphical models and
Bayesian networks have also been recognized to be unnecessarily stringent under
certain circumstances. This observation has led to the proposal of several
generalizations that aim at more relaxed constraints by which the models can
impose local or context-specific dependence structures. Here we consider an
additional class of such models, termed as stratified graphical models. We
develop a method for Bayesian learning of these models by deriving an
analytical expression for the marginal likelihood of data under a specific
subclass of decomposable stratified models. A non-reversible Markov chain Monte
Carlo approach is further used to identify models that are highly supported by
the posterior distribution over the model space. Our method is illustrated and
compared with ordinary graphical models through application to several real and
synthetic datasets.


title: Magnetoplasmons in rotating dusty plasmas

abstract:
  A rotating dusty plasma apparatus was constructed to provide the possibility
of experimental emulation of extremely high magnetic fields by means of the
Coriolis force, observable in a co-rotating measurement frame. We present
collective excitation spectra for different rotation rates with a magnetic
induction equivalent of up to 3200 Tesla. We identify the onset of
magnetoplasmon-equivalent mode dispersion in the rotating macroscopic
two-dimensional single-layer dusty plasma. The experimental results are
supported by molecular dynamics simulations of 2D magnetized Yukawa systems.


title:
Spontaneous electric polarization and Magneto-dielectric coupling in
  ceramic multiferroic Co3TeO6

abstract:
  We report observation of magneto-electric and magneto-dielectric couplings in
ceramic Co3TeO6. Temperature dependent DC magnetization and dielectric constant
measurements together indicate coupling between magnetic order and electronic
polarization. Strong anomaly in dielectric constant at ~ 18K in zero magnetic
field indicates presence of spontaneous polarization. Observations like weak
ferromagnetic order at lower temperature, field and temperature dependences of
the ferroelectric transition provide experimental verification of the recent
theoretical proposal by P. Toledano et al., Phys. Rev. B 85, 214439 (2012). We
provide direct evidence of spin-phonon coupling as possible origin of magnetic
order.


title: Hanbury Brown and Twiss Correlations in Quantum Hall Systems

abstract:
  We study a Hanbury Brown and Twiss (HBT) interferometer formed with chiral
edge channels of a quantum Hall system. HBT cross-correlations are calculated
for a device operating both in the integer and fractional quantum Hall regimes,
the latter at Laughlin filling fractions. We find that in both cases, when the
current is dominated by electron tunneling, current-current correlations show
antibunching, characteristic of fermionic correlations. When the
current-current correlations are dominated by quasiparticle tunneling, the
correlations reveal bunching, characteristic of bosons. For electron tunneling
we use Keldysh technique, and show that the result for fractional filling
factors can be obtained in a simple way from the results of the integer case.
It is shown that quasiparticle-dominated cross-current correlations can be
analyzed by means of a quantum master equation approach. We present here a
detailed derivation of the results of Ref. [Phys. Rev. Lett. 109, 106802
(2012)] and generalize them to all Laughlin fractions.


title:
Highly Scalable Neuromorphic Hardware with 1-bit Stochastic
  nano-Synapses

abstract:
  Thermodynamic-driven filament formation in redox-based resistive memory and
the impact of thermal fluctuations on switching probability of emerging
magnetic switches are probabilistic phenomena in nature, and thus, processes of
binary switching in these nonvolatile memories are stochastic and vary from
switching cycle-to-switching cycle, in the same device, and from
device-to-device, hence, they provide a rich in-situ spatiotemporal stochastic
characteristic. This work presents a highly scalable neuromorphic hardware
based on crossbar array of 1-bit resistive crosspoints as distributed
stochastic synapses. The network shows a robust performance in emulating
selectivity of synaptic potentials in neurons of primary visual cortex to the
orientation of a visual image. The proposed model could be configured to accept
a wide range of nanodevices.


title: Brillouin zone labelling for quasicrystals

abstract:
  We propose a scheme to determine the energy-band dispersion of quasicrystals
which does not require any periodic approximation and which directly provides
the correct structure of the extended Brillouin zones. In the gap labelling
viewpoint, this allow to transpose the measure of the integrated
density-of-states to the measure of the effective Brillouin-zone areas that are
uniquely determined by the position of the Bragg peaks. Moreover we show that
the Bragg vectors can be determined by the stability analysis of the law of
recurrence used to generate the quasicrystal. Our analysis of the gap labelling
in the quasi-momentum space opens the way to an experimental proof of the gap
labelling itself within the framework of an optics experiment, polaritons, or
with ultracold atoms.


title: Local Brunella's Alternative I. RICH Foliations

abstract:
  This paper is devoted to studying the structure of codimension one singular
holomorphic foliations on $({\mathbb C}^3,0)$ without invariant germs of
analytic surface. We focus on the so-called CH-foliations, that is, foliations
without saddle nodes in two dimensional sections. Considering a reduction of
singularities, we detect the possible existence of "nodal components", which
are a higher dimensional version of the nodal separators in dimension two. If
the foliation is without nodal components, we prove that all the leaves in a
neighborhood of the origin contain at least one germ of analytic curve at the
origin. We also study the structure of nodal components for the case of
"Relatively Isolated CH-foliations" and we show that they cut the dicritical
components or they exit the origin through a non compact invariant curve. This
allows us to give a precise statement of a local version of Brunella's
alternative: if we do not have an invariant surface, all the leaves contain a
germ of analytic curve or it is possible to detect the nodal components in the
generic points of the singular curves before doing the reduction of
singularities.


title: Spot Transit: Cheaper Internet Transit for Elastic Traffic

abstract:
  We advocate to create a \emph{spot} Internet transit market, where transit is
sold using the under-utilized backbone capacity at a lower price. The providers
can improve profit by capitalizing the perishable capacity, and customers can
buy transit on-demand without a minimum commitment level for elastic traffic,
and as a result improve its surplus (i.e. utility gains). We conduct a
systematic study of the economical benefits of spot transit both theoretically
and empirically. We propose a simple analytical framework with a general demand
function, and solve the pricing problem of maximizing the expected profit,
taking into account the revenue loss of regular transit when spot transit
traffic hikes. We rigorously prove the price advantage of spot transit, as well
as profit and surplus improvements for tier-1 ISPs and customers, respectively.
Using real-world price data and traffic statistics of 6 IXPs with more than
1000 ISPs, we quantitatively evaluate spot transit and show that significant
financial benefits can be achieved in both absolute and relative terms, robust
to parameter values.


title: Classical and stochastic L\"owner-Kufarev equations

abstract:
  In this paper we present a historical and scientific account of the
development of the theory of the L\"owner-Kufarev classical and stochastic
equations spanning the 90-year period from the seminal paper by K.L\"owner in
1923 to recent generalizations and stochastic versions and their relations to
conformal field theory.


title: Quantum error correction in a solid-state hybrid spin register

abstract:
  Hybrid quantum systems seek to combine the strength of its constituents to
master the fundamental conflicting requirements of quantum technology: fast and
accurate systems control together with perfect shielding from the environment,
including the measurements apparatus, to achieve long quantum coherence.
Excellent examples for hybrid quantum systems are heterogeneous spin systems
where electron spins are used for readout and control while nuclear spins are
used as long-lived quantum bits. Here we show that joint initialization,
projective readout and fast local and non-local gate operations are no longer
conflicting requirements in those systems, even under ambient conditions. We
demonstrate high-fidelity initialization of a whole spin register (99 %) and
single-shot readout of multiple individual nuclear spins by using the ancillary
electron spin of a nitrogen-vacancy defect in diamond. Implementation of a
novel non-local gate generic to our hybrid electron-nuclear quantum register
allows to prepare entangled states of three nuclear spins, with fidelities
exceeding 85 %. An important tool for scalable quantum computation is quantum
error correction. Combining, for the first time, optimal-control based error
avoidance with error correction, we realize a three-qubit phase-flip error
correction algorithm. Utilizing optimal control, all of the above algorithms
achieve fidelities approaching fault tolerant quantum operation, thus paving
the way to large scale integrations. Our techniques can be used to improve
scaling of quantum networks relying on diamond spins, phosphorous in silicon or
other spin systems like quantum dots, silicon carbide or rare earth ions in
solids.


title: Nongeneric J-holomorphic curves and singular inflation

abstract:
  This paper investigates the geometry of a symplectic 4-manifold $(M,\om)$
relative to a J-holomorphic normal crossing divisor S. Extending work by Biran
(in Invent. Math. 1999), we give conditions under which a homology class $A\in
H_2(M;\Z)$ with nontrivial Gromov invariant has an embedded J-holomorphic
representative for some S-compatible J. This holds for example if the class $A$
can be represented by an embedded sphere, or if the components of S are spheres
with self-intersection -2. We also show that inflation relative to S is always
possible, a result that allows one to calculate the relative symplectic cone.
It also has important applications to various embedding problems, for example
of ellipsoids or Lagrangian submanifolds.


title:
Magnetic control of Coulomb scattering and terahertz transitions among
  excitons

abstract:
  Time-resolved terahertz quenching studies of the magnetoexcitonic
photoluminescence from GaAs/AlGaAs quantum wells are performed. A microscopic
theory is developed to analyze the experiments. Detailed experiment-theory
comparisons reveal a remarkable magnetic-field controllability of the Coulomb
and terahertz interactions in the excitonic system.


title:
Prediction of half metallic properties in Ti\raisebox{-.2ex}{\scriptsize
  2}CoSi Heusler alloy based on density functional theory

abstract:
  The electronic and magnetic properties of Ti\raisebox{-.2ex}{\scriptsize
2}CoSi Heusler compound are investigated using density functional calculations.
The optimized lattice constant is found to be 6.030 A. The compound is a
half-metallic ferromagnet with an energy gap in minority spin channel of 0.652
eV at equilibrium lattice constant, which leads to a 100% spin-polarization.
The obtained total magnetic moment from spin-polarized calculations is 3.0
$\mu_{B}$ for values of lattice constants higher than 5.941 A. The
half-metallicity is spoiled for a compressed volume of 4%, suggesting a
possible application as pressure sensitive material.


title:
Almost Oscillation Criteria for Second Order Neutral Difference Equation
  with Quasidifferences

abstract:
  Using the Riccati transformation techniques, we will extend some almost
oscillation criteria for the second-order nonlinear neutral difference equation
with quasidifferences $$\Delta\left(r_n\left(\Delta \left(x_n+c
x_{n-k}\right)\right)^{\gamma}\right)+q_nx_{n+1}^{\alpha}=e_n.$$


title:
Weak Convergence to Stable L\'evy Processes for Nonuniformly Hyperbolic
  Dynamical Systems

abstract:
  We consider weak invariance principles (functional limit theorems) in the
domain of a stable law. A general result is obtained on lifting such limit laws
from an induced dynamical system to the original system. An important class of
examples covered by our result are Pomeau-Manneville intermittency maps, where
convergence for the induced system is in the standard Skorohod J_1 topology.
For the full system, convergence in the J_1 topology fails, but we prove
convergence in the M_1 topology.


title: Fibr\'es principaux sur les corps valu\'es hens\'eliens

abstract:
  Let (K,v) be a valued field, Y a K-variety, G an algebraic group over K (not
necessarily smooth), and f: X->Y a G-torsor over Y. We consider the induced map
X(K)-->Y(K), which is continuous for the topologies deduced from the valuation.
Let I denote the image of this map.
  We prove that if (K,v) is henselian and its completion is a separable
extension, then:
  - I is locally closed in Y(K);
  - the induced surjection X(K)-->I is a principal bundle with group G(K) (also
topologized by the valuation).


title: A quantum access network

abstract:
  The theoretically proven security of quantum key distribution (QKD) could
revolutionise how information exchange is protected in the future. Several
field tests of QKD have proven it to be a reliable technology for cryptographic
key exchange and have demonstrated nodal networks of point-to-point links.
However, so far no convincing answer has been given to the question of how to
extend the scope of QKD beyond niche applications in dedicated high security
networks. Here we show that adopting simple and cost-effective
telecommunication technologies to form a quantum access network can greatly
expand the number of users in quantum networks and therefore vastly broaden
their appeal. We are able to demonstrate that a high-speed single-photon
detector positioned at a network node can be shared between up to 64 users for
exchanging secret keys with the node, thereby significantly reducing the
hardware requirements for each user added to the network. This
point-to-multipoint architecture removes one of the main obstacles restricting
the widespread application of QKD. It presents a viable method for realising
multi-user QKD networks with resource efficiency and brings QKD closer to
becoming the first widespread technology based on quantum physics.


title:
Multiple Transition States and Roaming in Ion-Molecule Reactions: a
  Phase Space Perspective

abstract:
  We provide a dynamical interpretation of the recently identified `roaming'
mechanism for molecular dissociation reactions in terms of geometrical
structures in phase space. These are NHIMs (Normally Hyperbolic Invariant
Manifolds) and their stable/unstable manifolds that define transition states
for ion-molecule association or dissociation reactions. The associated dividing
surfaces rigorously define a roaming region of phase space, in which both
reactive and nonreactive trajectories can be trapped for arbitrarily long
times.

categories: physics.chem-ph cond-mat.stat-mech math.DS nlin.CD


title: A Fuzzy expert system for goalkeeper quality recognition

abstract:
  Goalkeeper (GK) is an expert in soccer and goalkeeping is a complete
professional job. In fact, achieving success seems impossible without a
reliable GK. His effect in successes and failures is more dominant than other
players. The most visible mistakes in a game are those of goalkeeper's. In this
paper the expert fuzzy system is used as a suitable tool to study the quality
of a goalkeeper and compare it with others. Previously done researches are used
to find the goalkeepers' indexes in soccer. Soccer experts have found that a
successful GK should have some qualifications. A new pattern is offered here
which is called "Soccer goalkeeper quality recognition using fuzzy expert
systems". This pattern has some important capabilities. Firstly, among some
goalkeepers the one with the best quality for the main team arrange can be
chosen. Secondly, the need to expert coaches for choosing a GK using their
senses and experiences decreases a lot. Thirdly, in the survey of a GK,
quantitative criteria can be included, and finally this pattern is simple and
easy to understand.


title: A Note On 3D N=2 Dualities: Real Mass Flow And Partition Function

abstract:
  We study two well-known classes of dualities in three dimensional N=2
supersymmetric field theories. In the first class there are non trivial
interactions involving monopole operators while in the second class the dual
gauge theories have Chern-Simons terms in the action. An RG flows connecting
the first dual pair to the second one has been studied in the past and tested
on the partition function on the squashed three sphere. Recently an opposite RG
flow connecting the second dual pair to the first one has been studied in the
case of unitary gauge groups. In this paper we study this flow on the partition
function on the squashed three sphere. We verify that the equality between the
partition functions of the original dual models is preserved in the IR, where
the other dual pair is reached. We generalize the analysis to the case of
symplectic and of orthogonal groups.


title: Random time series in Astronomy

abstract:
  Progress in astronomy comes from interpreting the signals encoded in the
light received from distant objects: the distribution of light over the sky
(images), over photon wavelength (spectrum), over polarization angle, and over
time (usually called light curves by astronomers). In the time domain we see
transient events such as supernovae, gamma-ray bursts, and other powerful
explosions; we see periodic phenomena such as the orbits of planets around
nearby stars, radio pulsars, and pulsations of stars in nearby galaxies; and
persistent aperiodic variations (`noise') from powerful systems like accreting
black holes. I review just a few of the recent and future challenges in the
burgeoning area of Time Domain Astrophysics, with particular attention to
persistently variable sources, the recovery of reliable noise power spectra
from sparsely sampled time series, higher-order properties of accreting black
holes, and time delays and correlations in multivariate time series.


title:
Dissipative preparation of phase- and number-squeezed states with
  ultracold atoms

abstract:
  We develop a dissipative quantum state preparation scheme for the creation of
phase- and number-squeezed states. It utilizes ultracold atoms in a double-well
configuration immersed in a background Bose-Einstein condensate, with the
latter consisting of an atom species different from the atoms in the double
well and acting as a dissipative quantum reservoir. We derive a master equation
for this system starting from microscopic physics, and show that squeezing
develops on a time scale proportional to $1/N$, where $N$ is the number of
particles in the double well. This scaling, caused by bosonic enhancement,
allows us to make the time scale for the creation of squeezed states very
short. The lifetime of squeezed states is limited by dephasing arising from the
intrinsic structure of the setup. However, the dephasing can be avoided by
stroboscopically switching the driving off and on. We show that this approach
leads to robust stationary squeezed states. Finally, we provide the necessary
ingredients for a potential experimental implementation by specifying a
parameter regime for rubidium atoms that leads to squeezed states.


title:
Half metallic state and magnetic properties versus the lattice constant
  in Ti\raisebox{-.2ex}{\scriptsize 2}CoSn Heusler compound: an ab initio study

abstract:
  The half metallic properties of Ti\raisebox{-.2ex}{\scriptsize 2}CoSn
full-Heusler compound is studied within the framework of the density functional
theory with the Perdew Burke Ernzerhof generalized gradient approximation
(GGA). Structural optimization was performed and the calculated equilibrium
lattice constant is 6.340 A. The spin up band of compound has metallic
character and spin down band is semiconducting with an indirect gap of 0.598 eV
at equilibrium lattice constant. For the lattice parameter, ranging from 6.193
to 6.884 A the compound presents 100% spin polarization and a total magnetic
moment of 3$\mu_{B}$.


title:
Critical behavior of spin and chiral degrees of freedom in
  three-dimensional disordered XY models studied by the nonequilibrium aging
  method

abstract:
  The critical behavior of the gauge-glass and the XY spin-glass models in
three dimensions is studied by analyzing their nonequilibrium aging dynamics. A
new numerical method, which relies on the calculation of the two-time
correlation and integrated response functions, is used to determine both the
critical temperature and the nonequilibrium scaling exponents, both for spin
and chiral degrees of freedom. First, the ferromagnetic XY model is studied to
validate this nonequilibirum aging method (NAM), since for this nondisordered
system we can compare with known results obtained with standard equilibrium and
nonequilibrium techniques. When applied to the case of the gauge-glass model,
we show that the NAM allows us to obtain precise and reliable values of its
critical quantities, improving previous estimates. The XY spin-glass model with
both Gaussian and bimodal bond distributions, is analyzed in more detail. The
spin and the chiral two-time correlation and integrated response functions are
calculated in our simulations. The results obtained mainly for Gaussian and, to
a lesser extent, for bimodal interactions, support the existence of a
spin-chiral decoupling scenario, where the chiral order occurs at a finite
temperature while the spin degrees of freedom order at very low or zero
temperature.


title:
Study on the effect of humidity and dust on leakage current of bulk
  micro-MEGAS detector

abstract:
  In this paper, the effect of humidity and dust trapped in avalanche region on
leakage current of bulk micro-MEGAS detector is studied. Pyralux PC1025 layers
of DuPont are introduced in bulk technique and micro-MEGAS detector with
pillars of 300{\mu}m in diameter is fabricated. Leakage current is tested in
air with different humidity. Silicon carbide powder and PMMA (polymethyl
methacrylate) powder are added as dust to avalanche region. Leakage current
with and without powder is tested in air and results are depicted in the same
figure. Test results indicate that leakage current increases with both storage
humidity and test humidity, and also increases when powder is introduced in
avalanche region.


title:
Changes in adsorption heights upon self-assembly of bicomponent
  supramolecular networks

abstract:
  Codeposition of two molecular species [CuPc (donor) and PFP (acceptor)] on
noble metal (111) surfaces leads to the self-assembly of an ordered mixed layer
with maximized donor-acceptor contact area. The main driving force behind this
arrangement is assumed to be the intermolecular C-F...H-C hydrogen-bond
interactions. Such interactions would be maximized for a coplanar molecular
arrangement. However, precise measurement of molecule-substrate distances in
the molecular mixture reveals significantly larger adsorption heights for PFP
than for CuPc. Most surprisingly, instead of leveling to increase hydrogen bond
interactions, the height difference is enhanced in mixed layers as compared to
the heights found in single component CuPc and PFP layers, resulting in an
overall reduced interaction with the underlying substrate. The influence of the
increased height of PFP on the interface dipole is investigated through work
function measurements.


title: The problem of minimal resistance for functions and domains

abstract:
  Here we solve the problem posed by Comte and Lachand-Robert in (2001). Take a
bounded domain \Omega in R^2 and a piecewise smooth non-positive function u :
\bar{\Omega} \to R vanishing on the boundary of \Omega. Consider a flow of
point particles falling vertically down and reflected elastically from the
graph of u. It is assumed that each particle is reflected no more than once (no
multiple reflections are allowed); then the resistance of the graph to the flow
is expressed as F(u;\Omega) = \frac{1}{|\Omega|} \int_\Omega (1 + |\nabla
u(x)|^2)^{-1} dx. It is required to find \inf_{\Omega,u} F(u;\Omega). One can
easily see that |\nabla u(x)| < 1 for all regular x \in \Omega, and therefore
one always has F(u;\Omega) > 1/2.
  We prove that the infimum of F is exactly 1/2. This result is somewhat
paradoxical, and the proof is inspired by, and is partly similar to, the
paradoxical solution given by Besicovitch to the Kakeya problem.


title:
Band structure calculations of Ti\raisebox{-.2ex}{\scriptsize 2}FeSn: a
  new half-metallic compound

abstract:
  Within the framework of density functional theory, the electronic structure
and magnetic properties have been studied for the
Ti\raisebox{-.2ex}{\scriptsize 2}FeSn full-Heusler compound. The ferromagnetic
state is found to be energetically more favorable than paramagnetic and
antiferromagnetic states. The spin-polarized results show that
Ti\raisebox{-.2ex}{\scriptsize 2}FeSn compound has half-metallic ferromagnetic
character with a total spin moment of $2 \mu_{B}$ and a band gap in the
minority spin channel of 0.489 eV, at the equilibrium lattice constant a=6.342
A.


title:
Crackling Noise in Fractional Percolation -- Randomly distributed
  discontinuous jumps in explosive percolation

abstract:
  Crackling noise is a common feature in many systems that are pushed slowly,
the most familiar instance of which is the sound made by a sheet of paper when
crumpled. In percolation and regular aggregation clusters of any size merge
until a giant component dominates the entire system. Here we establish
`fractional percolation' where the coalescence of clusters that substantially
differ in size are systematically suppressed. We identify and study percolation
models that exhibit multiple jumps in the order parameter where the position
and magnitude of the jumps are randomly distributed - characteristic of
crackling noise. This enables us to express crackling noise as a result of the
simple concept of fractional percolation. In particular, the framework allows
us to link percolation with phenomena exhibiting non-self-averaging and power
law fluctuations such as Barkhausen noise in ferromagnets.


title: Nanoscale elucidation of Na,K-ATPase isoforms in dendritic spines

abstract:
  The dimensions of neuronal synapses suggest that optical super-resolution
imaging methods are necessary for thorough investigation of protein
distributions and interactions. Nanoscopic evaluation of neuronal samples has
presented practical hurdles, but advancing methods are making synaptic protein
topology and quantification measurements feasible. This work explores the
application of Photoactivated Localization Microscopy (PALM) pointilistic
super-resolution imaging for investigation of the membrane bound sodium pump,
the Na,K-ATPase, in matured neurons.
  Two isoforms of the sodium pump (ATP1a1 and ATP1a3) were studied in cultured
neurons using the PALM-compatible fluorescent proteins PAGFP and mEos.
Nanoscopic imaging reveals a compartmentalized distribution of sodium pumps in
dendritic spines. Several nanoclusters of pumps are typically found in the
spine head and relatively few in the spine neck. The density of sodium pumps
was estimated from a quantification of detected single molecules to 600-800
pump copies/um2 in the spine heads.
  We have utilized PALM for dissection of nanoscale localization in mature
cultured neurons and demonstrated similar topology and quantification estimates
with PAGFP and mEos. PALM topology assessments of the sodium pump appeared
similar to previous STED studies, though quantification estimates varied
notably, implying that sample labeling strategies and choice of nanoscopic
imaging method are critical factors for correct quantification.


title: Piezoresistance in Silicon and its nanostructures

abstract:
  Piezoresistance is the change in the electrical resistance, or more
specifically the resistivity, of a solid induced by an applied mechanical
stress. The origin of this effect in bulk, crystalline materials like Silicon,
is principally a change in the electronic structure which leads to a
modification of the charge carriers effective mass. The last few years have
seen a rising interest in the piezoresistive properties of semiconductor
nanostructures, motivated in large part by claims of a giant piezoresistance
effect in Silicon nanowires that is more than two orders of magnitude bigger
than the known bulk effect. This review aims to present the controversy
surrounding claims and counter-claims of giant piezoresistance in Silicon
nanostructures by presenting a summary of the major works carried out over the
last 10 years. The main conclusions that can be drawn from the literature are
that i) reproducible evidence for a giant piezoresistance effect in un-gated
Silicon nanowires is limited, ii) in gated nanowires a giant effect has been
reproduced by several authors, iii) the giant effect is fundamentally different
from either the bulk Silicon piezoresistance or that due to quantum confinement
in accumulation layers and heterostructures, the evidence pointing to an
electrostatic origin for the piezoresistance, iv) released nanowires tend to
have slightly larger piezoresistance coefficients than un-released nanowires,
and v) insufficient work has been performed on bottom-up grown nanowires to be
able to rule out a fundamental difference in their properties when compared
with top-down nanowires. On the basis of this, future possible research
directions are suggested.


title: LDA+U and tight-binding electronic structure of InN nanowires

abstract:
  In this paper we employ a combined {\it ab initio} and tight-binding approach
to obtain the electronic and optical properties of hydrogenated InN nanowires.
We first discuss InN band structure for the wurtzite structure calculated at
the LDA+U level and use this information to extract the parameters needed for
an empirical tight-binging implementation. These parameters are then employed
to calculate the electronic and optical properties of InN nanowires in a
diameter range that would not be affordable by {\it ab initio} techniques. The
reliability of the large nanowires results is assessed by explicitly comparing
the electronic structure of a small diameter wire studied both at LDA+U and
tight-binding level.


title:
Spin-Seebeck effect on the surface of topological insulator due to
  nonequilibrium spin-polarization parallel to the direction of thermally
  driven electronic transport

abstract:
  We study the transverse spin-Seebeck effect (SSE) on the surface of a
three-dimensional topological insulator (TI) thin film, such as Bi$_2$Se$_3$,
which is sandwiched between two normal metal leads. The temperature bias
$\Delta T$ applied between the leads generates surface charge current which
becomes spin-polarized due to strong spin-orbit coupling on the TI surface,
with polarization vector acquiring a component $P_x \simeq 60%$ {\em parallel
to the direction of transport}. When the third nonmagnetic voltage probe is
attached to the portion of the TI surface across its width $L_y$, pure spin
current will be injected into the probe where the inverse spin Hall effect
(ISHE) converts it into a voltage signal
\mbox{$|V_\mathrm{ISHE}|^\mathrm{max}/\Delta T \simeq 2.5$ $\mu$V/K} (assuming
the SH angle of Pt voltage probe and $L_y=1$ mm). The existence of predicted
nonequilibrium spin-polarization parallel to the direction of electronic
transport and the corresponding electron-driven SSE crucially relies on
orienting quintuple layers (QLs) of Bi$_2$Se$_3$ {\em orthogonal} to the TI
surface and {\em tilted} by $45^\circ$ with respect to the direction of
transport. Our analysis is based on the Landauer-B\"{u}ttiker-type formula for
spin currents in the leads of a multi-terminal quantum-coherent junction, which
is constructed using nonequilibrium Green function formalism within which we
show how to take into account arbitrary orientation of QLs via the self-energy
describing coupling between semi-infinite normal metal leads and TI.


title: Characteristic boundary value problems: estimates from H1 to L2

abstract:
  Motivated by the study of certain non linear free-boundary value problems for
hyperbolic systems of partial differential equations arising in
Magneto-Hydrodynamics, in this paper we show that an a priori estimate of the
solution to certain boundary value problems, in the conormal Sobolev space
H1_tan, can be transformed into an L2 a priori estimate of the same problem.


title:
Exploring Programmable Self-Assembly in Non-DNA based Molecular
  Computing

abstract:
  Self-assembly is a phenomenon observed in nature at all scales where
autonomous entities build complex structures, without external influences nor
centralised master plan. Modelling such entities and programming correct
interactions among them is crucial for controlling the manufacture of desired
complex structures at the molecular and supramolecular scale. This work focuses
on a programmability model for non DNA-based molecules and complex behaviour
analysis of their self-assembled conformations. In particular, we look into
modelling, programming and simulation of porphyrin molecules self-assembly and
apply Kolgomorov complexity-based techniques to classify and assess simulation
results in terms of information content. The analysis focuses on phase
transition, clustering, variability and parameter discovery which as a whole
pave the way to the notion of complex systems programmability.

categories: cs.CC cs.AI cs.CE physics.comp-ph physics.data-an


title:
The Dragon and the Computer: Why Intellectual Property Theft is
  Compatible with Chinese Cyber-Warfare Doctrine

abstract:
  Along with the USA and Russia, China is often considered one of the leading
cyber-powers in the world. In this excerpt, we explore how Chinese military
thought, developed in the 1990s, influenced their cyber-operations in the early
2000s. In particular, we examine the ideas of "Unrestricted Warfare" and
"Active Offense" and discuss how they can permit for the theft of intellectual
property. We then specifically look at how the case study of Operation Aurora,
a cyber-operation directed against many major U.S. technology and defense
firms, reflects some of these ideas.


title:
The effect of Pauli blockade on spin-dependent diffusion in a degenerate
  electron gas

abstract:
  Spin-polarized transport of photo-electrons in bulk, p-type GaAs is
investigated in the Pauli blockade regime. In contrast to usual spin diffusion
processes in which the spin polarization decreases with distance traveled due
to spin relaxation, images of the polarized photo-luminescence reveal a
spin-filter effect in which the spin polarization increases during transport
over the first 2 microns from 26 % to 38 %. This is shown to be a direct
consequence of the Pauli Principle and the associated quantum degeneracy
pressure which results in a spin-dependent increase in the minority carrier
diffusion constants and mobilities. The central role played by the quantum
degeneracy pressure is confirmed via the observation of a spin-dependent
increase in the photo-electron volume and a spin-charge coupling description of
this is presented.


title:
Location, Location, Location: Data-Intensive Distributed Computing in
  the Cloud

abstract:
  When orchestrating highly distributed and data-intensive Web service
workflows the geographical placement of the orchestration engine can greatly
affect the overall performance of a workflow. Orchestration engines are
typically run from within an organisations' network, and may have to transfer
data across long geographical distances, which in turn increases execution time
and degrades the overall performance of a workflow. In this paper we present
CloudForecast: a Web service framework and analysis tool which given a workflow
specification, computes the optimal Amazon EC2 Cloud region to automatically
deploy the orchestration engine and execute the workflow. We use geographical
distance of the workflow, network latency and HTTP round-trip time between
Amazon Cloud regions and the workflow nodes to find a ranking of Cloud regions.
This combined set of simple metrics effectively predicts where the workflow
orchestration engine should be deployed in order to reduce overall execution
time.
  We evaluate our approach by executing randomly generated data-intensive
workflows deployed on the PlanetLab platform in order to rank Amazon EC2 Cloud
regions. Our experimental results show that our proposed optimisation strategy,
depending on the particular workflow, can speed up execution time on average by
82.25% compared to local execution. We also show that the standard deviation of
execution time is reduced by an average of almost 65% using the optimisation
strategy.


title: Order-preserving pattern matching with k mismatches

abstract:
  We study a generalization of the recently introduced order-preserving pattern
matching, where instead of looking for an exact copy of the pattern, we only
require that the relative order between the elements is the same. In our
variant, we additionally allow up to k mismatches between the pattern and the
text, and the goal is to construct an efficient algorithm for small values of
k. For a pattern of length m and a text of length n, our algorithm detects an
order-preserving occurrence with up to k mismatches in O(n(loglogm + kloglogk))
time.


title:
Principal eigenvalue of the fractional Laplacian with a large
  incompressible drift

abstract:
  We add a divergence-free drift with increasing magnitude to the fractional
Laplacian on a bounded smooth domain, and discuss the behavior of the principal
eigenvalue for the Dirichlet problem. The eigenvalue remains bounded if and
only if the drift has non-trivial first integrals in the domain of the
quadratic form of the fractional Laplacian.


title:
Maximizing the Spread of Stable Influence: Leveraging Norm-driven
  Moral-Motivation for Green Behavior Change in Networks

abstract:
  In an effort to understand why individuals choose to participate in
personally-expensive pro-environmental behaviors, environmental and behavioral
economists have examined a moral-motivation model in which the decision to
adopt a pro-environmental behavior depends on the society-wide market share of
that behavior. An increasing body of practical research on adoption of
pro-environmental behavior emphasizes the importance of encouragement from
local social contacts and messaging about locally-embraced norms: we respond by
extending the moral-motivation model to a social networks setting. We obtain a
new decision rule: an individual adopts a pro-environmental behavior if he or
she observes a certain threshold of adoption within their local social
neighborhood. This gives rise to a concurrent update process which describes
adoption of a pro-environmental behavior spreading through a network. The
original moral-motivation model corresponds to the special case of our network
version in a complete graph.
  By improving convergence results, we formulate modest-size Integer Programs
that accurately (but not efficiently) find minimum-size sets of nodes that
convert the entire network, or alternately that maximize long-term adoption in
the network given a limited number of nodes which may be temporarily converted.
Issues of stability in determining long-term adoption are key. We give hardness
of approximation results for these optimization problems. We demonstrate that
there exist classes of networks which qualitatively have severely different
behavior than the non-networked version, and provide preliminary computational
results in in modestly-sized highly-clustered small-world networks related to
the famous small-world networks of Watts and Strogatz.


title:
Completeness and Bethe root distribution of the spin-1/2 Heisenberg
  chain with arbitrary boundary fields

abstract:
  Recently, the XXX spin chain with arbitrary boundary fields was successfully
solved [1] via the off-diagonal Bethe ansatz method [2]. The correctness and
the completeness of this solution were numerically verified by Nepomechie for
one choice of the parameterizations [3]. In this paper, we discuss further the
completeness of another parameterization of the Bethe ansatz equations and its
reduction to the parallel boundary field case. The numerical results show that
when the relative angle between the boundary fields turns to zero, both the T-Q
relations and the Bethe ansatz equations are reduced to the ones obtained by
the conventional Bethe ansatz methods. This allows us to establish a one-to-one
correspondence between the Bethe roots of the unparallel boundary field case
and those of the parallel boundary field case. In the thermodynamic limit,
those two sets of Bethe roots tend to the same and the contribution of the
relative angle to the energy is in the order of 1/N.

categories: cond-mat.stat-mech hep-th math-ph math.MP


title:
Indirect coupling between localized magnetic moments in zero-dimensional
  graphene nanostructures (quantum dots)

abstract:
  The indirect Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling between on-site
magnetic impurities is studied for two kinds of graphene nanoflakes consisting
of approximately 100 carbon atoms, posessing either zigzag or armchair edge.
The tight-binding Hamiltonian with Hubbard term is used in non-perturbative
calculations of coupling between the impurities placed at the edge of the
structure. In general, for zigzag-edged nanoflakes a pronounced coupling robust
against charge doping is found, while for armchair-edged structures the
interaction is weaker and much more sensitive to charge doping. Also the
distance dependence of indirect exchange differs significantly for both edge
forms.


title: BRST symmetry and Darboux transformations in Abelian 2-form gauge theory

abstract:
  We analyse the constraints of an Abelian 2-form gauge theory using
Faddeev-Jackiw symplectic formalism. Further, this theory is treated as a
constrained system in the context of Batalin-Fradkin-Vilkovisky formalism to
retrieve the BRST symmetry. Using the fields decompositions the effective
action for Abelian 2-form gauge theory is written in terms of diagonalized
uncanonical part and BRST exact one. The nilpotent BRST and contracting
homotopy $\sigma $ closed transformations with field redefinitions are shown as
the Darboux transformations used in the Faddeev-Jackiw formalism.


title:
Probability Law For the Euclidean Distance Between Two Planar Random
  Flights

abstract:
  We consider two independent symmetric Markov random flights $\bold Z_1(t)$
and $\bold Z_2(t)$ performed by the particles that simultaneously start from
the origin of the Euclidean plane $\Bbb R^2$ in random directions distributed
uniformly on the unit circumference $S_1$ and move with constant finite
velocities $c_1>0, \; c_2>0$, respectively. The new random directions are
taking uniformly on $S_1$ at random time instants that form independent
homogeneous Poisson flows of rates $\lambda_1>0, \; \lambda_2>0$.
  The probability distribution function of the Euclidean distance
$$\rho(t)=\Vert \bold Z_1(t) - \bold Z_2(t) \Vert, \qquad t>0,$$ between $\bold
Z_1(t)$ and $\bold Z_2(t)$ at arbitrary time instant $t>0$, is obtained.


title:
The RAVE harvest: from the relation between abundances and kinematic of
  the Milky Way stars to tools for the abundance analysis of the spectra

abstract:
  RAVE is a spectroscopic survey of the Milky Way which collected more than
500,000 stellar spectra of nearby stars in the Galaxy. The RAVE consortium
analysed these spectra to obtain radial velocities, stellar parameters and
chemical abundances. These data, together with spatial and kinematic
information like positions, proper motions, and distance estimations, make the
RAVE database a rich source for galactic archaeology. I present recent
investigations on the chemo-kinematic relations and chemical gradients in the
Milky Way disk by using RAVE data and compare our results with the Besancon
models. I also present the code SPACE, an evolution of the RAVE chemical
pipeline, which integrates the measurements of stellar parameters and chemical
abundances in one single process.


title: Acausality and Nonunique Evolution in Generalized Teleparallel Gravity

abstract:
  We show the existence of physical superluminal modes and acausality in the
Brans-Dicke type of extension of teleparallel gravity that includes F(T)
gravity and teleparallel dark energy as special cases. We derive the
characteristic hypersurface for the extra degrees of freedom in the theory,
thereby showing that the time evolution is not unique and closed causal curves
can appear. Furthermore, we present a concrete disastrous solution in Bianchi
type I spacetime, in which the anisotropy in expansion can be any function of
time, and thus anisotropy can emerge suddenly, a simple demonstration that the
theory is physically problematic.


title:
A report on the magnetic order of transition-metal $\delta$-doped cubic
  ZnO

abstract:
  Preliminary results on the properties of transition-metal (Ti, V, Cr, Mn, Fe,
Co, Ni) $\delta$-doped ZnO are reported. Using \emph{ab-initio} electronic
structure calculations the magnetic order is studied assuming both the cubic
rock-salt and zinc-blende structures for ZnO. The ground state magnetic order
is found to depend strongly on the transition-metal atom.


title:
Dendritic flux avalanches in superconducting films of different
  thickness

abstract:
  At low temperatures the critical state in superconducting films can be
unstable with respect to thermomagnetic dendritic avalanches. By numerical
simulations of disk-shaped superconductors, we consider how the dynamics and
morphology of the avalanches depend on the disk thickness. We find that as the
disks get thicker, the jumps in magnetic moment caused by the avalanches get
larger and the threshold magnetic field for the appearance of the first
avalanche increases. At the same time, the branches are straighter and the
number of branches decreases. Comparison with theory suggests that strong
spatial disorder to some extent cancels the stabilizing effects of the
substrate kept at constant temperature.


title: Integrable Hierarchy of the Quantum Benjamin-Ono Equation

abstract:
  A hierarchy of pairwise commuting Hamiltonians for the quantum periodic
Benjamin-Ono equation is constructed by using the Lax matrix. The eigenvectors
of these Hamiltonians are Jack symmetric functions of infinitely many variables
$x_1,x_2,\ldots$. This construction provides explicit expressions for the
Hamiltonians in terms of the power sum symmetric functions
$p_n=x_1^n+x_2^n+\cdots$ and is based on our recent results from [Comm. Math.
Phys. 324 (2013), 831-849, arXiv:1212.2781].


title:
The Geminid meteoroid stream as a potential meteorite dropper: a case
  study

abstract:
  A Geminid fireball with an absolute magnitude of -13 was observed over the
south of Spain on Dec. 15, 2009. This extraordinarily bright event (the
brightest Geminid ever recorded by our team) was imaged from two meteor
observing stations operated by the SPanish Meteor Network (SPMN). The bolide
exhibited fast and quasi-periodic variations in brightness, a behaviour
typically associated to the rotation of the parent meteoroid. The inferred
tensile strength of this particle was found to be significantly higher that the
typical values obtained for Geminid meteoroids. The fireball penetrated in the
atmosphere till a final height of about 25 km above the ground level and a
non-zero terminal mass was calculated at the ending point of the luminous
trajectory. In this way, the observational evidence points to the existence of
a population of meteoroids in the higher end of the Geminid mass distribution
capable of producing meteorites. From the relative chemical abundances inferred
from the emission spectrum of this bolide we conclude that the Geminid-forming
materials are similar to some primitive carbonaceous chondrite groups. Then, we
conclude that in meteorite collections from cold deserts, capable to preserve
meteorites of few tens of grams, some rare groups of carbonaceous chondrites
could be coming from the Geminid parent body: (3200) Phaeton.


title: Software Defined Radio Architecture Survey for Cognitive Testbeds

abstract:
  In this paper we present a survey of existing prototypes dedicated to
software defined radio. We propose a classification related to the
architectural organization of the pro- totypes and provide some conclusions
about the most promising architectures. This study should be useful for
cognitive radio testbed designers who have to choose between many possible
computing platforms. We also introduce a new cognitive radio testbed currently
under construction and explain how this study have influenced the test-bed
designers choices.


title:
Dyck tilings and the homogeneous Garnir relations for graded Specht
  modules

abstract:
  Suppose $\lambda$ and $\mu$ are integer partitions with
$\lambda\supseteq\mu$. Kenyon and Wilson have introduced the notion of a
cover-inclusive Dyck tiling of the skew Young diagram $\lambda\setminus\mu$,
which has applications in the study of double-dimer models. We examine these
tilings in more detail, giving various equivalent conditions and then proving a
recurrence which we use to show that the entries of the transition matrix
between two bases for a certain permutation module for the symmetric group are
given by counting cover-inclusive Dyck tilings. We go on to consider the
inverse of this matrix, showing that its entries are determined by what we call
cover-expansive Dyck tilings. The fact that these two matrices are mutual
inverses allows us to recover the main result of Kenyon and Wilson.
  We then discuss the connections with recent results of Kim et al, who give, a
simple expression for the sum, over all $\mu$, of the number of cover-inclusive
Dyck tilings of $\lambda\setminus\mu$. Our results provide a new proof of this
result. Finally, we show how to use our results to obtain simpler expressions
for the homogeneous Garnir relations for the universal Specht modules
introduced by Kleshchev, Mathas and Ram for the cyclotomic quiver Hecke
algebras.


title: Hardware Implementation of the GPS authentication

abstract:
  In this paper, we explore new area/throughput trade- offs for the Girault,
Poupard and Stern authentication protocol (GPS). This authentication protocol
was selected in the NESSIE competition and is even part of the standard ISO/IEC
9798. The originality of our work comes from the fact that we exploit a fixed
key to increase the throughput. It leads us to implement GPS using the Chapman
constant multiplier. This parallel implementation is 40 times faster but 10
times bigger than the reference serial one. We propose to serialize this
multiplier to reduce its area at the cost of lower throughput. Our hybrid
Chapman's multiplier is 8 times faster but only twice bigger than the
reference. Results presented here allow designers to adapt the performance of
GPS authentication to their hardware resources. The complete GPS prover side is
also integrated in the network stack of the PowWow sensor which contains an
Actel IGLOO AGL250 FPGA as a proof of concept.


title: Certain particular families of graphicable algebras

abstract:
  In this paper, we introduce some particular families of graphicable algebras
obtained by following a relatively new line of research, initiated previously
by some of the authors. It consists of the use of certain objects of Discrete
Mathematics, mainly graphs and digraphs, to facilitate the study of graphicable
algebras, which are a subset of evolution algebras.


title: Recurrence and non-uniformity of bracket polynomials

abstract:
  A bracket polynomial on the integers is a function formed using the
operations of addition, multiplication and taking fractional parts. For a
fairly large class of bracket polynomials we show that if p is a bracket
polynomial of degree k-1 on [N] then the function f defined by f(n) = e(p(n))
has Gowers U^k[N]-norm bounded away from zero, uniformly in N.
  We establish this result by first reducing it to a certain recurrence
property of sets of bracket polynomials. Specifically, for a fairly large class
of bracket polynomials we show that if p_1, ..., p_r are bracket polynomials
then their values, modulo 1, are all close to zero on at least some constant
proportion of the points 1, ..., N.
  The proofs rely on two deep results from the literature. The first is work of
V. Bergelson and A. Leibman showing that an arbitrary bracket polynomial can be
expressed in terms of a polynomial sequence on a nilmanifold. The second is a
theorem of B. Green and T. Tao describing the quantitative distribution
properties of such polynomial sequences.
  We give elementary alternative proofs of the first result, without reference
to nilmanifolds, in certain "low-complexity" special cases.


title:
Graphs of Edge-Intersecting Non-Splitting Paths in a Tree:
  Representations of Holes-Part II

abstract:
  Given a tree and a set P of non-trivial simple paths on it, VPT(P) is the VPT
graph (i.e. the vertex intersection graph) of the paths P, and EPT(P) is the
EPT graph (i.e. the edge intersection graph) of P. These graphs have been
extensively studied in the literature. Given two (edge) intersecting paths in a
graph, their split vertices is the set of vertices having degree at least 3 in
their union. A pair of (edge) intersecting paths is termed non-splitting if
they do not have split vertices (namely if their union is a path). We define
the graph ENPT(P) of edge intersecting non-splitting paths of a tree, termed
the ENPT graph, as the graph having a vertex for each path in P, and an edge
between every pair of vertices representing two paths that are both
edge-intersecting and non-splitting. A graph G is an ENPT graph if there is a
tree T and a set of paths P of T such that G=ENPT(P), and we say that <T,P> is
a representation of G.
  Our goal is to characterize the representation of chordless ENPT cycles
(holes). To achieve this goal, we first assume that the EPT graph induced by
the vertices of an ENPT hole is given. In [2] we introduce three assumptions
(P1), (P2), (P3) defined on EPT, ENPT pairs of graphs. In the same study, we
define two problems HamiltonianPairRec, P3-HamiltonianPairRec and characterize
the representations of ENPT holes that satisfy (P1), (P2), (P3).
  In this work, we continue our work by relaxing these three assumptions one by
one. We characterize the representations of ENPT holes satisfying (P3) by
providing a polynomial-time algorithm to solve P3-HamiltonianPairRec. We also
show that there does not exist a polynomial-time algorithm to solve
HamiltonianPairRec, unless P=NP.


title: Homotopy classes of Newtonian spaces

abstract:
  We study notions of homotopy in the Newtonian space $N^{1,p}(X;Y)$ of Sobolev
type maps between metric spaces. After studying the properties and relations of
two different notions we prove a compactness result for sequences in homotopy
classes with controlled homotopies.


title: On nonnegative unbiased estimators

abstract:
  We study the existence of algorithms generating almost surely nonnegative
unbiased estimators. We show that given a nonconstant real-valued function $f$
and a sequence of unbiased estimators of $\lambda\in\mathbb{R}$, there is no
algorithm yielding almost surely nonnegative unbiased estimators of
$f(\lambda)\in\mathbb{R}^+$. The study is motivated by pseudo-marginal Monte
Carlo algorithms that rely on such nonnegative unbiased estimators. These
methods allow "exact inference" in intractable models, in the sense that
integrals with respect to a target distribution can be estimated without any
systematic error, even though the associated probability density function
cannot be evaluated pointwise. We discuss the consequences of our results on
the applicability of pseudo-marginal algorithms and thus on the possibility of
exact inference in intractable models. We illustrate our study with particular
choices of functions $f$ corresponding to known challenges in statistics, such
as exact simulation of diffusions, inference in large datasets and doubly
intractable distributions.


title: On the Stability of Generalized Second Price Auctions with Budgets

abstract:
  The Generalized Second Price (GSP) auction used typically to model sponsored
search auctions does not include the notion of budget constraints, which is
present in practice. Motivated by this, we introduce the different variants of
GSP auctions that take budgets into account in natural ways. We examine their
stability by focusing on the existence of Nash equilibria and envy-free
assignments. We highlight the differences between these mechanisms and find
that only some of them exhibit both notions of stability. This shows the
importance of carefully picking the right mechanism to ensure stable outcomes
in the presence of budgets


title: A Proof that the Maximal Rank for Plane Quartics is Seven

abstract:
  At the time of writing, the general problem of finding the maximal Waring
rank for homogeneous polynomials of fixed degree and number of variables (or,
equivalently, the maximal symmetric rank for symmetric tensors of fixed order
and in fixed dimension) is still unsolved. To our knowledge, the answer for
ternary quartics is not widely known and can only be found among the results of
a master's thesis by Johannes Kleppe at the University of Oslo (1999). In the
present work we give a (direct) proof that the maximal rank for plane quartics
is seven, following the elementary geometric idea of splitting power sum
decompositions along three suitable lines.


title: Testing time variability of gamma-ray flux

abstract:
  A way of examining a hypothetical non--zero $\gamma$--ray signal for the time
changes is presented. The time variability of the recently observed
$\gamma$--ray source PKS 2155--304 is discussed. Several measurements were
found to be excessive or deficient with large significances on time scales of
months and days.


title: Online Bin Covering: Expectations vs. Guarantees

abstract:
  Bin covering is a dual version of classic bin packing. Thus, the goal is to
cover as many bins as possible, where covering a bin means packing items of
total size at least one in the bin.
  For online bin covering, competitive analysis fails to distinguish between
most algorithms of interest; all "reasonable" algorithms have a competitive
ratio of 1/2. Thus, in order to get a better understanding of the combinatorial
difficulties in solving this problem, we turn to other performance measures,
namely relative worst order, random order, and max/max analysis, as well as
analyzing input with restricted or uniformly distributed item sizes. In this
way, our study also supplements the ongoing systematic studies of the relative
strengths of various performance measures.
  Two classic algorithms for online bin packing that have natural dual versions
are Harmonic and Next-Fit. Even though the algorithms are quite different in
nature, the dual versions are not separated by competitive analysis. We make
the case that when guarantees are needed, even under restricted input
sequences, dual Harmonic is preferable. In addition, we establish quite robust
theoretical results showing that if items come from a uniform distribution or
even if just the ordering of items is uniformly random, then dual Next-Fit is
the right choice.


title:
Generation of random dynamical systems from fractional stochastic delay
  differential equations

abstract:
  In this note we prove that a fractional stochastic delay differential
equation which satisfies natural regularity conditions generates a continuous
random dynamical system on a subspace of a H\"older space which is separable.


title: Simulating Organogenesis in COMSOL: Cell-based Signaling Models

abstract:
  Most models of biological pattern formation are simulated on continuous
domains even though cells are discrete objects that provide internal boundaries
to the diffusion of regulatory components. In our previous papers on simulating
organogenesis in COMSOL (Germann et al COMSOL Conf Procedings 2011; Menshykau
and Iber, COMSOL Conf Proceedings 2012) we discussed methods to efficiently
solve signaling models on static and growing continuous domains. Here we
discuss COMSOL-based methods to study spatio-temporal signaling models at
cellular resolution with subcellular compartments, i.e. cell membrane,
cytoplasm, and nucleus.


title:
Hiding in the Shadows: Searching for Planets in Pre--transitional and
  Transitional Disks

abstract:
  Transitional and pre--transitional disks can be explained by a number of
mechanisms. This work aims to find a single observationally detectable marker
that would imply a planetary origin for the gap and, therefore, indirectly
indicate the presence of a young planet. N-body simulations were conducted to
investigate the effect of an embedded planet of one Jupiter mass on the
production of instantaneous collisional dust derived from a background
planetesimal disk. Our new model allows us to predict the dust distribution and
resulting observable markers with greater accuracy than previous work.
Dynamical influences from a planet on a circular orbit are shown to enhance
dust production in the disk interior and exterior to the planet orbit while
removing planetesimals from the the orbit itself creating a clearly defined
gap. In the case of an eccentric planet the gap opened by the planet is not as
clear as the circular case but there is a detectable asymmetry in the dust
disk.


title:
Healthy vector spaces and spicy Hopf algebras (with applications to the
  growth rate of geodesic chords and to intermediate volume growth on manifolds
  of non-finite type)

abstract:
  We give lower bounds for the growth of the number of Reeb chords and for the
volume growth of Reeb flows on spherizations over closed manifolds M that are
not of finite type, have virtually polycyclic fundamental group, and satisfy a
mild assumption on the homology of the based loop space.
  For the special case of geodesic flows, these lower bounds are:
  (i) For any Riemannian metric on M, any pair of non-conjugate points p,q in
M, and every component C of the space of paths from p to q, the number of
geodesics in C of length at most T grows at least like e^{\sqrt T}.
  (ii) The exponent of the volume growth of any geodesic flow on M is at least
1/2.
  We obtain these results by combining new algebraic results on the growth of
certain filtered Hopf algebras with known results on Floer homology.


title:
Nanoarchitecture in the black wings of Troides magellanus: a natural
  case of absorption enhancement in photonic materials

abstract:
  The birdwings butterfly Troides magellanus possesses interesting properties
for light and thermal radiation management. The black wings of the male exhibit
strong (98%) absorption of visible light as well as two strong absorption peaks
in the infrared both due to chitin. These peaks are located in the spectral
region where the black body emits at 313K. The study of absorption enhancement
in this butterfly could be helpful to design highly absorbent biomimetic
materials. Observations of the wings using a scanning electron microscope (SEM)
reveal that the scales covering the wings are deeply nanostructured. A periodic
three-dimensional (3D) model of the scale nanoarchitecture is elaborated and
used for numerical transfer-matrix simulations of the absorption spectrum. The
complex refractive index of the wing material is approximated by a
multi-oscillator Lorentz model, leading to a broad absorption in the visible
range as well as two peaks in the infrared. The absorption peak intensities
turn out to be dependent on the complexity of the nanostructures. This result
clearly demonstrates a structural effect on the absorption. Finally, a
comparison with a planar layer of identical refractive index and material
volume lead us to conclude that the absorption is enhanced by nanostructures.


title: Lovelock theory and the AdS/CFT correspondence

abstract:
  Lovelock theory is the natural extension of general relativity to higher
dimensions. It can be also thought of as a toy model for ghost-free higher
curvature corrections in gravitational theories. It admits a family of AdS
vacua, which provides an appealing arena to explore different holographic
aspects in a broader setup within the context of the AdS/CFT correspondence. We
will elaborate on these features and review previous work concerning the
constraints that Lovelock theory entails on the CFT parameters when imposing
conditions like unitarity, positivity of the energy or causality.


title: Capacity-aware back-pressure traffic signal control

abstract:
  The control of a network of signalized intersections is considered. Previous
work demonstrates that the so-called back-pressure control provides stability
guarantees, assuming infinite queues capacities. In this paper, we highlight
the failing of current back-pressure control under finite capacities by
identifying sources of non work-conservation and congestion propagation. We
propose the use of a normalized pressure which guarantees work conservation and
mitigates congestion propagation, while ensuring fairness at low traffic
densities, and recovering original back-pressure as capacities grow to
infinity. This capacity-aware back-pressure control allows to improve
performance as congestion increases, as indicated by simulation results, and
keeps the key benefits of back-pressure: ability to be distributed over
intersections and O(1) complexity.


title: Estimates for measures of sections of convex bodies

abstract:
  A $\sqrt{n}$ estimate in the hyperplane problem with arbitrary measures has
recently been proved in \cite{K3}. In this note we present analogs of this
result for sections of lower dimensions and in the complex case. We deduce
these inequalities from stability in comparison problems for different
generalizations of intersection bodies.


title: Simulation of an Axial Vircator

abstract:
  An algorithm of particle-in-cell simulations is described and tested to aid
further the actual design of simple vircators working on axially symmetric
modes. The methods of correction of the numerical solution, have been chosen
and jointly tested, allow the stable simulation of the fast nonlinear multiflow
dynamics of virtual cathode formation and evolution, as well as the fields
generated by the virtual cathode. The selected combination of the correction
methods can be straightforwardly generalized to the case of axially
nonsymmetric modes, while the parameters of these correction methods can be
widely used to improve an agreement between the simulation predictions and the
experimental data.

categories: physics.acc-ph nlin.CD physics.comp-ph physics.plasm-ph