title:
Adaptive Switching Between Single/Concurrent Link Scheme in Single Hop
  MIMO Networks

abstract:
  Concurrent link communications built on multi-antenna systems have been
widely adopted for spatial resource exploitation. MIMA-MAC, a classical MIMO
MAC protocol utilizing concurrent link scheme, is able to provide superior link
throughput over conventional single link MAC (under certain isolated link
topologies). However, when utilizing rich link adaptation functions in MIMO
systems, there exists a non-ignorable probability that MIMA-MAC's throughput
will be lower than that of single link scheme (such probability is dominated by
the statistics of instantaneous link topology and channel response). Inspired
by this critical observation, and for adapting to various link topologies, this
paper will present a novel MAC design that can adaptively switch between single
or concurrent link scheme. With the aim of absolutely outperforming the single
link MAC, here our optimization criterion is to guarantee a throughput result
that is either better than or at least equal to single link MAC's counterpart.
To highlight the design rationale, we first present an idealized implementation
having network information perfectly known in a non-causal way. Then for
realistic applications, we further develop a practical MAC implementation
dealing with realistic system impairments (distributed handshaking and
imperfect channel estimation). Simulation results validate that link throughput
in our MAC is higher than or equal to single link MAC's counterpart with
minimized outage probabilities. And for ergodic link throughput, our proposed
MAC can outperform the single link MAC and MIMA-MAC by around 20{%}-30{%}.


title:
An Efficient Quantum Algorithm and Circuit to Generate Eigenstates of
  SU(2) and SU(3) Representations

abstract:
  This thesis presents an efficient quantum algorithm and explicit circuits for
generating eigenstates of arbitrary SU(2) and SU(3) representations. These
include a wide variety of highly entangled states. The algorithm uses Schur
transform that rotates the input computational basis states to the output Schur
basis states with resources polynomial in number of qudits n. Using the fact
that quantum logic is reversible, we accomplish the desired result using the
inverse Schur transform. The algorithm can be easily generalized to any
arbitrary higher groups.


title:
On the Evidence for Cosmic Variation of the Fine Structure Constant
  (II): A Semi-Parametric Bayesian Model Selection Analysis of the Quasar
  Dataset

abstract:
  In the second paper of this series we extend our Bayesian reanalysis of the
evidence for a cosmic variation of the fine structure constant to the
semi-parametric modelling regime. By adopting a mixture of Dirichlet processes
prior for the unexplained errors in each instrumental subgroup of the benchmark
quasar dataset we go some way towards freeing our model selection procedure
from the apparent subjectivity of a fixed distributional form. Despite the
infinite-dimensional domain of the error hierarchy so constructed we are able
to demonstrate a recursive scheme for marginal likelihood estimation with
prior-sensitivity analysis directly analogous to that presented in Paper I,
thereby allowing the robustness of our posterior Bayes factors to
hyper-parameter choice and model specification to be readily verified. In the
course of this work we elucidate various similarities between unexplained error
problems in the seemingly disparate fields of astronomy and clinical
meta-analysis, and we highlight a number of sophisticated techniques for
handling such problems made available by past research in the latter. It is our
hope that the novel approach to semi-parametric model selection demonstrated
herein may serve as a useful reference for others exploring this potentially
difficult class of error model.


title:
Non compound nucleus fission events and standard saddle-point
  statistical model

abstract:
  The large body of experimental data on the fission fragments anisotropies are
analyzed in several heavy-ion induced fission reaction systems. The entrance
channel mass asymmetry parameters of these systems put on the both sides of the
Businaro-Gallone mass asymmetry parameters. The role of the mass numbers of the
projectile and the target in the prediction of a normal or an anomalous
behavior in angular anisotropy, as well as the validity of standard
saddle-point statistical model are considered. The average contribution of non
compound nucleus fission for the systems with an anomalous behavior in
anisotropy are also determined. PACS numbers: 25.70.Jj *Corresponding author:
s.soheyli@basu.ac.ir


title: Non-collinear magnetic structures of TbCoO$_3$ and DyCoO$_3$

abstract:
  The orthoperovskites TbCoO$_3$ and DyCoO$_3$ with Co$^{3+}$ in a non-magnetic
low-spin state have been investigated by neutron diffraction down to 0.25 K.
Magnetic ordering is evidenced below $T_N=3.3$ K and 3.6 K, respectively, and
the ordered arrangements are of canted type, A$_x$G$_y$ for TbCoO$_3$ and
G$_x$A$_y$ for DyCoO$_3$ in Bertaut's notation. The experiments are confronted
with the first-principle calculations of the crystal field and magnetism of
Tb$^{3+}$ and Dy$^{3+}$ ions, located in the $Pbnm$ structure on sites of $C_s$
point symmetry. Both these ions exhibit an Ising behavior, which originates in
the lowest energy levels, in particular in accidental doublet of non-Kramers
Tb$^{3+}$ ($4f^8$ configuration) and in ground Kramers doublet of Dy$^{3+}$
($4f^9$) and it is the actual reason for the non-collinear AFM structures. Very
good agreement between the experiment and theory is found. For comparison,
calculations of the crystal field and magnetism for other systems with Kramers
ions, NdCoO$_3$ and SmCoO$_3$, are also included.


title:
On hyperbolic systems with entropy velocity covariant under the action
  of a group

abstract:
  For hyperbolic systems of conservation laws in one space dimension with a
mathematical entropy, we define the notion of entropy velocity. Then we give
sufficient conditions for such a system to be covariant under the action of a
group of space-time transformations. These conditions naturally introduce a
representation of the group in the space of states. We construct such
hyperbolic system from the knowledge of data on the manifold of null velocity.
We apply these ideas for Galileo, Lorentz and circular groups. We focus on
particular non trivial examples for two by two systems of conservation laws.


title:
Initial versus tangent stiffness-based Rayleigh damping in inelastic
  time history seismic analyses

abstract:
  In the inelastic time history analyses of structures in seismic motion, part
of the seismic energy that is imparted to the structure is absorbed by the
inelastic structural model, and Rayleigh damping is commonly used in practice
as an additional energy dissipation source. It has been acknowledged that
Rayleigh damping models lack physical consistency and that, in turn, it must be
carefully used to avoid encountering unintended consequences as the appearance
of artificial damping. There are concerns raised by the mass proportional part
of Rayleigh damping, but they are not considered in this paper. As far as the
stiffness proportional part of Rayleigh damping is concerned, either the
initial structural stiffness or the updated tangent stiffness can be used. The
objective of this paper is to provide a comprehensive comparison of these two
types of Rayleigh damping models so that a practitioner (i) can objectively
choose the type of Rayleigh damping model that best fits her/his needs and (ii)
is provided with useful analytical tools to design Rayleigh damping model with
good control on the damping ratios throughout inelastic analysis. To that end,
a review of the literature dedicated to Rayleigh damping within these last two
decades is first presented; then, practical tools to control the modal damping
ratios throughout the time history analysis are developed; a simple example is
finally used to illustrate the differences resulting from the use of either
initial or tangent stiffness-based Rayleigh damping model.


title:
Noncoherence of some rings of holomorphic functions in several variables
  as an easy consequence of the one-variable case

abstract:
  Using the facts that the disk algebra and the Wiener algebra are not
coherent, we prove that the polydisc algebra, the ball algebra and the Wiener
algebra of the polydisc are not coherent.


title:
Generation of double-charged optical vortices on the basis of
  electrooptic Kerr effect

abstract:
  We show that double-charged optical vortices can be generated with the help
of Kerr electrooptic effect in either single crystals or isotropic media,
including gaseous and liquid ones. We analyze possibilities for the vortex
generation via the Kerr effect for different point group of symmetry and
formulate the appropriate conditions. We prove that the crystals, textures and
the isotropic media most suitable for the generation of double-charged optical
vortices should belong to the symmetry groups 622, 6mm, 6/mmm, 6, 6/m, inf/m,
inf, inf 2, inf mm, inf/mmm, inf/inf/mmm, and inf/inf2.


title: Asteroseismology with SuperWASP

abstract:
  The highly successful SuperWASP planetary transit finding programme has
surveyed a large fraction of both the northern and southern skies. There now
exists in the its archive over 420 billion photometric measurements for more
than 31 million stars. SuperWASP provides good quality photometry with a
precision exceeding 1% per observation in the approximate magnitude range 9 < V
< 12. The archive enables long-baseline, high-cadence studies of stellar
variability to be undertaken. An overview of the SuperWASP project is
presented, along with results which demonstrate the survey's asteroseismic
capabilities.


title: Tracking rare-isotope beams with microchannel plates

abstract:
  A system of two microchannel-plate detectors has been successfully
implemented for tracking projectile-fragmentation beams. The detectors provide
interaction positions, angles, and arrival times of ions at the reaction
target. The current design is an adaptation of an assembly used for low-energy
beams ($\sim$1.4 MeV/nucleon). In order to improve resolution in tracking
high-energy heavy-ion beams, the magnetic field strength between the
secondary-electron accelerating foil and the microchannel plate had to be
increased substantially. Results from an experiment using a 37-MeV/nucleon
${}^{56}$Ni beam show that the tracking system can achieve sub-nanosecond
timing resolution and a position resolution of $\sim$1 mm for beam intensities
up to $5\times10^{5}$ pps.


title: How to see an antistar

abstract:
  Polarization of photons emitted in weak decays occuring at distant star
allows to determine whether this star is made from antimatter. Even more
promissing is the observation of neutrinos (antineutrinos) produced at
neutronization (antineutronization) reactions at the beginning of SN
($\bar{SN}$) explosion.


title: Approximate Counting CSP Solutions Using Partition Function

abstract:
  We propose a new approximate method for counting the number of the solutions
for constraint satisfaction problem (CSP). The method derives from the
partition function based on introducing the free energy and capturing the
relationship of probabilities of variables and constraints, which requires the
marginal probabilities. It firstly obtains the marginal probabilities using the
belief propagation, and then computes the number of solutions according to the
partition function. This allows us to directly plug the marginal probabilities
into the partition function and efficiently count the number of solutions for
CSP. The experimental results show that our method can solve both random
problems and structural problems efficiently.


title:
On a functional equation for symmetric linear operators on $C^{*}$
  algebras

abstract:
  Let $A$ be a $C^{*}$ algebra and $T: A\rightarrow A$ be a linear map which
satisfies the functional equation
$\begin{cases}T(x)T(y)=T^{2}(xy)\\T(x^{*})=T(x)^{*} \end{cases}$ We prove that
under each of the following conditions, $T$ must be the trivial map
$T(x)=\lambda x$ for some $\lambda \in \mathbb{R}:$\\ \begin{enumerate} \item
$A$ is a simple $C^{*}$-algebra.
  \item $A$ is unital with trivial center and has a faithful trace such that
each zero-trace element lies in the closure of the span of commutator elements.
  \item $A=B(H)$ where H is a separable Hilbert space. \end{enumerate}
  For a given field $F$, we consider a similar functional equation
$$\begin{cases}T(x)T(y)=T^{2}(xy)\\T(x^{tr})=T(x)^{tr} \end{cases}$$ where $T$
is a linear map on $M_{n}(F)$ and "tr" is the transpose operator. We prove that
this functional equation has trivial solution for all $n\in \mathbb{N}$ if and
only if $F$ is a formally real field.


title:
Complexity of colouring problems restricted to unichord-free and
  \{square,unichord\}-free graphs

abstract:
  A \emph{unichord} in a graph is an edge that is the unique chord of a cycle.
A \emph{square} is an induced cycle on four vertices. A graph is
\emph{unichord-free} if none of its edges is a unichord. We give a slight
restatement of a known structure theorem for unichord-free graphs and use it to
show that, with the only exception of the complete graph $K_4$, every
square-free, unichord-free graph of maximum degree~3 can be total-coloured with
four colours. Our proof can be turned into a polynomial time algorithm that
actually outputs the colouring. This settles the class of square-free,
unichord-free graphs as a class for which edge-colouring is NP-complete but
total-colouring is polynomial.


title: Character Estimates of Adjoint Simple Lie Groups

abstract:
  Call a compact, connected, simple Lie group $G$ {\emph{adjoint simple}} if it
has trivial center. Let $C\subset G$ be a nontrivial conjugacy class, $e\in G$
the identity element of $G$. We prove the existence of an $N\in\mathbb{N}$,
depending on $G$ but not $C$, such that $e$ lies in the interior of $C^n$ for
all $n\geq N$. We then prove that a disk $D\subset\mathbb{C}$ of radius less
than 1, contained in the unit disk $D_1$ and tangent to $D_1$ at $z=1$,
contains the image of every normalized character $\chi(e)^{-1}\chi$ of $G$.


title:
Dynamical coupling and negative differential resistance from
  interactions across the molecule-electrode interface in molecular junctions

abstract:
  Negative differential resistance - a decrease in current with increasing bias
voltage - is a counter-intuitive effect that is observed in various molecular
junctions. Here, we present a novel mechanism that may be responsible for such
an effect, based on strong Coulomb interaction between electrons in the
molecule and electrons on the atoms closest to the molecule. The Coulomb
interaction induces electron-hole binding across the molecule-electrode
interface, resulting in a renormalized and enhanced molecule-electrode
coupling. Using a self-consistent non-equilibrium Green's function approach, we
show that the effective coupling is non-monotonic in bias voltage, leading to
negative differential resistance. The model is in accord with recent
experimental observations that showed a correlation between the negative
differential resistance and the coupling strength. We provide detailed
suggestions for experimental tests which may help to shed light on the origin
of the negative differential resistance. Finally, we demonstrate that the
interface Coulomb interaction affects not only the I-V curves but also the
thermoelectric properties of molecular junctions.


title:
Robust Periocular Recognition By Fusing Sparse Representations of Color
  and Geometry Information

abstract:
  In this paper, we propose a re-weighted elastic net (REN) model for biometric
recognition. The new model is applied to data separated into geometric and
color spatial components. The geometric information is extracted using a fast
cartoon - texture decomposition model based on a dual formulation of the total
variation norm allowing us to carry information about the overall geometry of
images. Color components are defined using linear and nonlinear color spaces,
namely the red-green-blue (RGB), chromaticity-brightness (CB) and
hue-saturation-value (HSV). Next, according to a Bayesian fusion-scheme, sparse
representations for classification purposes are obtained. The scheme is
numerically solved using a gradient projection (GP) algorithm. In the empirical
validation of the proposed model, we have chosen the periocular region, which
is an emerging trait known for its robustness against low quality data. Our
results were obtained in the publicly available UBIRIS.v2 data set and show
consistent improvements in recognition effectiveness when compared to related
state-of-the-art techniques.


title:
Self-similarity and stable clustering in a family of scale-free
  cosmologies

abstract:
  We study non-linear gravitational clustering from cold gaussian power-law
initial conditions in a family of scale-free EdS models, characterized by a
free parameter $\kappa$ fixing the ratio between the mass driving the expansion
and the mass which clusters. As in the "usual" EdS model, corresponding to
$\kappa=1$, self-similarity provides a powerful instrument to delimit the
physically relevant clustering resolved by a simulation. Likewise, if stable
clustering applies, it implies scale-free non-linear clustering. We derive the
corresponding exponent $\gamma_{sc} (n, \kappa)$ of the two point correlation
function. We then report the results of extensive N-body simulations, of
comparable size to those previously reported in the literature for the case
$\kappa=1$, and performed with an appropriate modification of the GADGET2 code.
We observe in all cases self-similarity in the two point correlations, down to
a lower cut-off which decreases monotonically in time in comoving coordinates.
The self-similar part of the non-linear correlation function is fitted well in
all cases by a single power-law with an exponent in good agreement with
$\gamma_{sc} (n, \kappa)$. Our results thus indicate that stable clustering
provides an excellent approximation to the non-linear correlation function over
the resolved self-similar scales, at least down to $\gamma_{sc} (n, \kappa)
\approx 1$, corresponding to the case $n=-2$ for $\kappa=1$. We conclude, in
contrast notably with the results of Smith et al. (2003), that a clear
identification of the breakdown of stable clustering in self-similar models -
and the possible existence of a "universal" region in which non-linear
clustering becomes independent of initial conditions - remains an important
open problem, which should be addressed further in significantly larger
simulations.


title:
Conditions and evidence for non-integrability in the
  Friedmann-Robertson-Walker Hamiltonian

abstract:
  This is an example of application of Ziglin-Morales-Ramis algebraic studies
in Hamiltonian integrability, more specifically the result by Morales, Ramis
and Sim\'o on higher-order variational equations, to the well-known
Friedmann-Robertson-Walker cosmological model. A previous paper by the author
formalises said variational systems in such a way allowing the simple
expression of notable elements of the differential Galois group needed to study
integrability. Using this formalisation and an alternative method already used
by other authors, we find sufficient conditions whose fulfillment would entail
very simple proofs of non-integrability -- both for the complete Hamiltonian, a
goal already achieved by other means by Coelho et al, and for a special open
case attracting recent attention.


title: Probing Wigner correlations in a suspended carbon nanotube

abstract:
  The influence of the electron-vibron coupling on the transport properties of
a strongly interacting quantum dot built in a suspended carbon nanotube is
analyzed. The latter is probed by a charged AFM tip scanned along the axis of
the CNT which induces oscillations of the chemical potential and of the linear
conductance. These oscillations are due to the competition between finite-size
effects and the formation of a Wigner molecule for strong interactions. Such
oscillations are shown to be suppressed by the electron-vibron coupling. The
suppression is more pronounced in the regime of weak Coulomb interactions,
which ensures that probing Wigner correlations in such a system is in principle
possible.


title: The Galactic Center Origin of a Subset of IceCube Neutrino Events

abstract:
  The center of the Milkyway is a host to energetic phenomena across many
electromagnetic wave-bands and now possibly of high-energy neutrinos. We show
that 5 out of 21 IceCube shower-like events, including a PeV event, likely
originated from the Galactic Center region. Hard spectrum and flux inferred
from these events are inconsistent with atmospheric neutrinos. The flux of
these neutrinos is consistent with an extrapolation of the gamma-ray flux
measured by Fermi-LAT from the inner Galactic region. This indicates a common
hadronic origin of both, powered by supernovae. Three other shower-like events
are spatially correlated with the Fermi bubbles, originating from the Galactic
Center activity, within the uncertainty of reconstructing their arrival
directions. Origin of the other neutrino events, including 7 track-like events,
is still elusive.


title:
Observation of Electron Energy Discretization in Strong Field Double
  Ionization

abstract:
  We report on the observation of discrete structures in the electron energy
distribution for strong field double ionization of Argon at 394 nm. The
experimental conditions were chosen in order to ensure a non-sequential
ejection of both electrons with an intermediate rescattering step. We have
found discrete ATI (above-threshold ionization) like peaks in the sum energy of
both electrons, as predicted by all quantum mechanical calculations. More
surprisingly however is the observation of two ATI combs in the energy
distribution of the individual electrons.


title: Dating the fall of Babylon and Ur thanks to Astronomical Events

abstract:
  The traditional date of 1595 BCE for the destruction of Babylon by the
Hittite king Mursili I is accepted by most historians for many years despite
notable controversies. This pivotal date is considered crucial to the various
calculations of the early chronology of the ancient Near East. According to the
Venus Tablet (Enuma Anu Enlil 63) which describes the rising and setting of
Venus during the reign of Ammisaduqa, there are only 4 possibilities implying 4
dates for the destruction of Ur (1912, 1944, 2004, 2064 BCE) but a tablet of
astronomical omens (Enuma Anu Enlil 20,21) mentions a lunar eclipse, dated
14/III/48, at the end of the reign of Shulgi and a lunar eclipse, dated
14/XII/24, at the end of the reign of Ibbi-Sin. Over the period 2200-1850 BCE
there are only 3 pairs of eclipses, spaced by 42 years, matching the
description of astronomical omens but only 1 agreeing with the previous 4
dates. The second way to check the date for the fall of Babylon is to rebuild
the chronology of this period thanks to synchronisms dated by astronomy from
Assyrian, Babylonian, Egyptian and Israelite chronologies which provide
synchronisms that can be dated independently. The Mesopotamian chronology of
this period is reconstructed using the number of Assyrian eponyms (1 a year)
and the length of Babylonian reigns combined with the set of synchronisms among
Assyrian and Babylonian kings in Annals. During the reign of Assur-dan I
(1179-1133) eponyms began on 1 Nisan instead of 1 Sippu, but Assyrian lunar
years without intercalation remained the norm until Tiglath-pileser I. As the
Babylonian year began on 1st Nisan (just after the spring equinox), Assyrian
years coincided with Babylonian lunar years with intercalation, thus the period
between Assur-dan I and Tiglath-pileser I was therefore transitional. Owing to
the Babylonian chronology and synchronisms it is possible to date other
chronologies.


title: On Euler's decomposition formula for qMZVs

abstract:
  In this short and elementary note we derive a q-generalization of Euler's
decomposition formula for the qMZVs recently introduced by Y. Ohno, J. Okuda,
and W. Zudilin. This answers a question posed by these authors in [10].


title:
Interaction and temperature effects on the pair correlation function of
  a strongly interacting 1D quantum dot

abstract:
  The pair correlation function of a strongly interacting one-dimensional
quantum dot is evaluated analytically within the framework of the spin coherent
Luttinger liquid model. The influence of electron interactions and temperature
on the competition between finite-size effects and electronic correlations is
analyzed, also in the regime of large numbers of particles. The development of
Wigner molecule correlations is observed as interactions get stronger. The
visibility of such signatures is enhanced for temperatures comparable with the
spin excitation energy of the system due to a suppression of the uncorrelated
Friedel contribution to the pair correlation function.


title:
Observation of two output light pulses from a partial wavelength
  converter preserving phase of an input light at a single-photon level

abstract:
  We experimentally demonstrate that both a converted and an unconverted light
pulses after wavelength conversion with various conversion efficiencies
preserve phase information of an input light at a single-photon level. In our
experiment, we converted temporally-separated two coherent light pulses with
average photon numbers of $\sim$ 0.1 at 780 nm to light pulses at 1522 nm by
using difference-frequency generation in a periodically-poled lithium niobate
waveguide. We observed a single-photon interference between
temporally-separated two modes for both the converted and the unconverted light
pulses at various values of the conversion efficiency. We observed interference
visibilities greater than 0.88 without suppressing the background noises for
any value of the conversion efficiency the wavelength converter achieves. At a
conversion efficiency of $\sim$ 0.5, the observed visibilities are 0.98 for the
unconverted light and 0.99 for the converted light.


title:
Temperature-induced emergence of Wigner correlations in a STM-probed
  one-dimensional quantum dot

abstract:
  The temperature-induced emergence of Wigner correlations over finite-size
effects in a strongly interacting one-dimensional quantum dot are studied in
the framework of the spin coherent Luttinger liquid. We demonstrate that, for
temperatures comparable with the zero mode spin excitations, Friedel
oscillations are suppressed by the thermal fluctuations of higher spin modes.
On the other hand, the Wigner oscillations, sensitive to the charge mode only,
are stable and become more visible. This behavior is proved to be robust both
in the thermal electron density and in the linear conductance in the presence
of an STM tip. This latter probe is not directly proportional to the electron
density and may confirm the above phenomena with complementary and additional
information.


title: Green galaxies in the COSMOS field

abstract:
  We present a research of morphologies, spectra and environments of $\approx$
2350 "green valley" galaxies at $0.2<z<1.0$ in the COSMOS field. The bimodality
of dust-corrected \nuvr\ color is used to define "green valley" (thereafter,
GV), which removes dusty star-forming galaxies from truly transiting galaxies
between blue cloud and red sequence. Morphological parameters of green galaxies
are intermediate between those of blue and red galaxy populations, both on the
Gini--Asymmetry and the Gini--M$_{\rm 20}$ planes. Approximately 60% to 70%
green disk galaxies have intermediate or big bulges, and only 5% to 10% are
pure disk systems, based on the morphological classification with Zurich
Estimator of Structural Types (ZEST). The obtained average spectra of green
galaxies are intermediate between blue and red ones in terms of \oii\,,
H$\alpha$ and H$\beta$ emission lines. Stellar population synthesis on the
average spectra show that green galaxies are averagely older than blue
galaxies, but younger than red galaxies. Green galaxies have similar projected
galaxy density ($\Sigma_{10}$) distribution with blue galaxies at $z>0.7$. At
$z<0.7$, the fractions of $M_{\ast}<10^{10.0}M_{\sun}$ green galaxies located
in dense environment are found to be significantly larger than those of blue
galaxies. The morphological and spectral properties of green galaxies are
consistent with the transiting population between blue cloud and red sequence.
The possible mechanisms for quenching star formation activities in green
galaxies are discussed. The importance of AGN feedback cannot be well
constrained in our study. Finally, our findings suggest that environment
conditions, most likely starvation and harassment, significantly affect the
transformation of $M_{\ast}<10^{10.0}M_{\sun}$ blue galaxies into red galaxies,
especially at $z<0.5$.


title: Carbon nanotube sensor for vibrating molecules

abstract:
  The transport properties of a CNT capacitively coupled to a molecule
vibrating along one of its librational modes are studied and its transport
properties analyzed in the presence of an STM tip. We evaluate the linear
charge and thermal conductances of the system and its thermopower. They are
dominated by position-dependent Franck-Condon factors, governed by a
position-dependent effective coupling constant peaked at the molecule position.
Both conductance and thermopower allow to extract some information on the
position of the molecule along the CNT. Crucially, however, thermopower sheds
also light on the vibrational levelspacing, allowing to obtain a more complete
characterization of the molecule even in the linear regime.


title:
Enhancements of Multi-class Support Vector Machine Construction from
  Binary Learners using Generalization Performance

abstract:
  We propose several novel methods for enhancing the multi-class SVMs by
applying the generalization performance of binary classifiers as the core idea.
This concept will be applied on the existing algorithms, i.e., the Decision
Directed Acyclic Graph (DDAG), the Adaptive Directed Acyclic Graphs (ADAG), and
Max Wins. Although in the previous approaches there have been many attempts to
use some information such as the margin size and the number of support vectors
as performance estimators for binary SVMs, they may not accurately reflect the
actual performance of the binary SVMs. We show that the generalization ability
evaluated via a cross-validation mechanism is more suitable to directly extract
the actual performance of binary SVMs. Our methods are built around this
performance measure, and each of them is crafted to overcome the weakness of
the previous algorithm. The proposed methods include the Reordering Adaptive
Directed Acyclic Graph (RADAG), Strong Elimination of the classifiers (SE),
Weak Elimination of the classifiers (WE), and Voting based Candidate Filtering
(VCF). Experimental results demonstrate that our methods give significantly
higher accuracy than all of the traditional ones. Especially, WE provides
significantly superior results compared to Max Wins which is recognized as the
state of the art algorithm in terms of both accuracy and classification speed
with two times faster in average.


title:
Renormalized Chern-Gauss-Bonnet formula for complete Kahler-Einstein
  metrics

abstract:
  We present a renormalized Gauss-Bonnet formula for approximate
Kahler-Einstein metrics on compact complex manifolds with pseudo-Einstein CR
boundaries. The boundary integral is given explicitly, and it is proved that it
gives a pseudo-Einstein invariant, which generalizes the Burns-Epstein
invariant.


title: Logarithmically-concave moment measures I

abstract:
  We discuss a certain Riemannian metric, related to the toric Kahler-Einstein
equation, that is associated in a linearly-invariant manner with a given
log-concave measure in R^n. We use this metric in order to bound the second
derivatives of the solution to the toric Kahler-Einstein equation, and in order
to obtain spectral-gap estimates similar to those of Payne and Weinberger.


title:
The Weyl Curvature Tensor, Cotton-York Tensor and Gravitational Waves: A
  covariant consideration

abstract:
  1+3 covariant approach to cosmological perturbation theory often employs the
electric part ($E_{ab}$), the magnetic part ($H_{ab}$) of the Weyl tensor or
the shear tensor ($\sigma_{ab}$) in a phenomenological description of
gravitational waves. The Cotton-York tensor is rarely mentioned in connection
with gravitational waves in this approach. This tensor acts as a source for the
magnetic part of the Weyl tensor which should not be neglected in studies of
gravitational waves in the 1+3 formalism. The tensor is only mentioned in
connection with studies of 'silent model' but even there the connection with
gravitational waves is not exhaustively explored. In this study, we demonstrate
that the Cotton-York tensor encodes contributions from both electric, magnetic
part of the Weyl tensor and in directly from the shear tensor. In our opinion,
this makes the Cotton-York tensor arguably the natural choice for linear
gravitational waves in the 1+3 covariant formalism. The tensor is cumbersome to
work with but that should negate its usefulness. It is conceivable that the
tensor would equally be useful in the metric approach, although we have not
demonstrated this in the current study. We contend that the use of only one of
the Weyl tensor or the shear tensor, although phenomenologically correct, leads
to loss of information. Such information is vital particularly when examining
the contribution of gravitational waves to the anisotropy of an almost
-Friedmann-Lamitre-Robertson-Walker (FLRW) universe. The recourse to this loss
is the use Cotton-York tensor.


title: Supersolid structure and excitation spectrum of soft-core bosons in 3D

abstract:
  By means of a mean-field method, we have studied the zero temperature
structure and excitation spectrum of a three-dimensional soft-core bosonic
system for a value of the interaction strength that favors a crystal structure
made of atomic nano-clusters arranged with FCC ordering. In addition to the
longitudinal and transverse phonon branches expected for a normal crystal, the
excitation spectrum shows a soft mode related to the breaking of gauge
symmetry, which signals a partial superfluid character of the solid. Additional
evidence of supersolidity is provided by the calculation of the superfluid
fraction, which shows a first-order drop, from 1 to 0.4, at the
liquid-supersolid transition and a monotonic decrease as the interaction
strength parameter is increased. The conditions for the coexistence of the
supersolid with the homogeneous superfluid are discussed, and the surface
tension of a representative solid-liquid interface is calculated.


title: Viscous fingering at ultralow interfacial tension

abstract:
  We experimentally study the viscous fingering instability in a fluid-fluid
phase separated colloid-polymer mixture by means of laser scanning confocal
microscopy and microfluidics. We focus on three aspects of the instability. (i)
The interface between the two demixed phases has an ultralow surface tension,
such that we can address the role of thermal interface fluctuations. (ii) We
image the interface in three dimensions allowing us to study the interplay
between interface curvature and flow. (iii) The displacing fluid wets all walls
completely, in contrast to traditional viscous fingering experiments, in which
the displaced fluid wets the walls. We also perform lattice Boltzmann
simulations, which help to interpret the experimental observations.


title: Spin textures of strongly correlated spin Hall quantum dots

abstract:
  We study the spin ordering of a quantum dot defined via magnetic barriers in
an interacting quantum spin Hall edge. The spin-resolved density-density
correlation functions are computed. We show that strong electron interactions
induce a ground state with a highly correlated spin pattern. The crossover from
the liquid-type correlations at weak interactions to the ground state spin
texture found at strong interactions parallels the formation of a
one-dimensional Wigner molecule in an ordinary strongly interacting quantum
dot.


title: A Practical Distributed Universal Construction with Unknown Participants

abstract:
  Modern distributed systems employ atomic read-modify-write primitives to
coordinate concurrent operations. Such primitives are typically built on top of
a central server, or rely on an agreement protocol. Both approaches provide a
universal construction, that is, a general mechanism to construct atomic and
responsive objects. These two techniques are however known to be inherently
costly. As a consequence, they may result in bottlenecks in applications using
them for coordination. In this paper, we investigate another direction to
implement a universal construction. Our idea is to delegate the implementation
of the universal construction to the clients, and solely implement a
distributed shared atomic memory at the servers side. The construction we
propose is obstruction-free. It can be implemented in a purely asynchronous
manner, and it does not assume the knowledge of the participants. It is built
on top of grafarius and racing objects, two novel shared abstractions that we
introduce in detail. To assess the benefits of our approach, we present a
prototype implementation on top of the Cassandra data store, and compare it
empirically to the Zookeeper coordination service.


title: Self-gravitating Newtonian disks revisited

abstract:
  Recent analytic results concerning stationary, self-gravitating fluids in
Newtonian theory are discussed. We give a theorem that forbids infinitely
extended fluids, depending on the assumed equation of state and the rotation
law. This part extends previous results that have been obtained for static
configurations. The second part discusses a Sobolev bound on the mass of the
fluid and a rigorous Jeans-type inequality that is valid in the stationary
case.


title:
Exploring the bulk of the BL Lac object population:1. parsec-scale radio
  structures

abstract:
  Context. The advent of Fermi is changing our understanding on the radio and
gamma-ray emission in Active Galactic Nuclei. Contrary to pre-Fermi ideas, BL
Lac objects are found to be the most abundant emitters in the gamma-ray band.
However, since they are relatively weak radio sources, most of their
parsec-scale structure and their multi-frequency properties are poorly
understood and/or have not been investigated in a systematically fashion. Aims.
Our main goal is to analyze the radio and gamma-ray emission properties of a
sample of 42 BL Lacs selected, for the first time in the literature, with no
constraint on their radio and gamma-ray flux densities/emission. Methods.
Thanks to new Very Long Baseline Array observations at 8 and 15 GHz for the
whole sample, we present here fundamental parameters such as radio flux
densities, spectral index information, and parsec-scale structure. Moreover, we
search for gamma-ray counterparts using data reported in the Second Catalog of
Fermi Gamma-ray sources. Results. Parsec-scale radio emission is observed in
the majority of the sources at both frequencies. Gamma-ray counterparts are
found for 14/42 sources. Conclusions. The comparison between our results in
radio and gamma-ray bands points out the presence of a large number of faint BL
Lacs showing "non classical" properties such as low source compactness, core
dominance, no gamma-ray emission and steep radio spectral indexes. A deeper
multiwavelength analysis will be needed.


title: Remarks on coarse triviality of asymptotic Assouad-Nagata dimension

abstract:
  We show for a given metric space $(X,d)$ of asymptotic dimension $n$ that
there exists a coarsely and topologically equivalent hyperbolic metric $d'$ of
the form $d' = f \circ d$ such that $(X,d')$ is of asymptotic Assouad-Nagata
dimension $n$. As a corollary we construct examples of spaces realising strict
inequality in the logarithmic law for AN-asdim of a Cartesian product. One of
them may be viewed as a counterexample to a specific kind of a Morita-type
theorem for AN-asdim.


title: Hilbert functions of monomial ideals containing a regular sequence

abstract:
  Let $M$ be an ideal in $K[x_1,...,x_n]$ ($K$ is a field) generated by
products of linear forms and containing a homogeneous regular sequence of some
length. We prove that ideals containing $M$ satisfy the Eisenbud-Green-Harris
conjecture and moreover prove that the Cohen-Macaulay property is preserved. We
conclude that monomial ideals satisfy this conjecture. We obtain that
$h$-vector of Cohen-Macaulay simplicial complex $\Delta$ is the $h$-vector of
Cohen-Macaulay $(a_1-1,...,a_t-1)$-balanced simplicial complex where $t$ is the
height of the Stanley-Reisner ideal of $\Delta$ and $(a_1,...,a_t)$ is the type
of some regular sequence contained in this ideal.


title: Warm and cold fermionic dark matter via freeze-in

abstract:
  The freeze-in mechanism of dark matter production provides a simple and
intriguing alternative to the WIMP paradigm. In this paper, we analyze whether
freeze-in can be used to account for the dark matter in the so-called singlet
fermionic model. In it, the SM is extended with only two additional fields, a
singlet scalar that mixes with the Higgs boson, and the dark matter particle, a
fermion assumed to be odd under a Z_2 symmetry. After numerically studying the
generation of dark matter, we analyze the dependence of the relic density with
respect to all the free parameters of the model. These results are then used to
obtain the regions of the parameter space that are compatible with the dark
matter constraint. We demonstrate that the observed dark matter abundance can
be explained via freeze-in over a wide range of masses extending down to the
keV range. As a result, warm and cold dark matter can be obtained in this
model. It is also possible to have dark matter masses well above the unitarity
bound for WIMPs.


title: Majorana spin liquid and dimensional reduction in Cs2CuCl4

abstract:
  The low-temperature behavior of the magnetic insulator Cs2CuCl4 can be
modeled by an anisotropic triangular lattice spin-1/2 Heisenberg
antiferromagnet with two different exchange couplings J and J' = J/3. We show
that in a wide range of magnetic fields the experimentally observed field
dependence of the crossover temperature T_c for spin-liquid behavior can be
explained within a mean-field theory based on the representation of spin
operators in terms of Majorana fermions. We also show that for small magnetic
fields the specific heat and the spin susceptibility both exhibit a maximum as
a function of temperature at T_c = J/2. In the spin-liquid regime, the Majorana
fermions can only propagate along the direction of the strongest bond, in
agreement with the dimensional reduction scenario advanced by Balents [Nature
(London) 464, 199 (2010)].


title: Uniform Random Sample and Symmetric Beta Distribution

abstract:
  N.L. Johnson and S. Kotz introduced in 1990 an interesting family of
symmetric distributions which is based on randomly weighted average from
uniform random samples. The only example that could be addressed to their work
is the so-called "uniformly randomly modified tin" distribution from which two
random samples have been computed. In this paper, we generalize a subfamily of
their symmetric distributions and identify a concrete instance of this
generalized subfamily. That instance turns out to belong to the family of
Johnson and Kotz, which had not seemingly received proper attention in the
literature.


title: Z-Boson Decays in a Strong Electromagnetic Field

abstract:
  The probability of Z-boson decay to a pair of charged fermions in a strong
electromagnetic field, is calculated. On the basis of a method that employs
exact solutions to relativistic wave equations for charged particles, analytic
expressions for the partial decay widths of Z-boson are obtained at an
arbitrary value the external-field strength. The total Z-boson decay width in
an intense electromagnetic field, is calculated by summing these results over
all known generations of charged leptons and quarks. It is found that, in the
region of relatively weak fields, the field-induced corrections to the standard
Z-boson decay width in a vacuum do not exceed 2%. As the external-field
strength increases, the total decay width develops oscillations against the
background of its gradual decrease to the absolute-minimum point. In the region
of strong fields the total decay width of Z-boson grows monotonically. In this
case the t-quark-production process, which is forbidden in the absence of an
external field, begins contributing significantly to the total decay width of
the Z-boson.


title:
Integration by Parts Formula and Smoothness of Densities of Solutions to
  SDEs with Locally Lipschitz Coefficients

abstract:
  In this work we prove the existence of a smooth density for the solution to
an SDE with locally Lipschitz and semimonotone drift, and will derive an
exponential decay for this density and all of its derivatives as well. Our main
tool in this paper is an integration by parts formula for the solution of the
mentioned SDE in the Wiener space. We construct an approximating sequence of
SDEs with globally Lipschitz drifts and obtain a uniform bound for the integral
of their solutions from which we derive the exponential decay for the
derivatives of the density of the original SDE.


title: Groupoids and the tomographic picture of quantum mechanics

abstract:
  The existing relation between the tomographic description of quantum states
and the convolution algebra of certain discrete groupoids represented on
Hilbert spaces will be discussed. The realizations of groupoid algebras based
on qudit, photon-number (Fock) states and symplectic tomography quantizers and
dequantizers will be constructed. Conditions for identifying the convolution
product of groupoid functions and the star--product arising from a
quantization--dequantization scheme will be given. A tomographic approach to
construct quasi--distributions out of suitable immersions of groupoids into
Hilbert spaces will be formulated and, finally, intertwining kernels for such
generalized symplectic tomograms will be evaluated explicitly.


title: Symmetry energy: nuclear masses and neutron stars

abstract:
  We describe the main features of our most recent Hartree-Fock-Bogoliubov
nuclear mass models, based on 16-parameter generalized Skyrme forces. They have
been fitted to the data of the 2012 Atomic Mass Evaluation, and favour a value
of 30 MeV for the symmetry coefficient J, the corresponding root-mean square
deviation being 0.549 MeV. We find that this conclusion is compatible with
measurements of neutron-skin thickness. By constraining the underlying
interactions to fit various equations of state of neutron matter calculated
{\it ab initio} our models are well adapted to a realistic and unified
treatment of all regions of neutron stars. We use our models to calculate the
composition, the equation of state, the mass-radius relation and the maximum
mass. Comparison with observations of neutron stars again favours a value of J
= 30 MeV.


title:
New approach to determine proton-nucleus interactions from experimental
  bremsstrahlung data

abstract:
  A new approach is presented to determine the proton-nucleus interactions from
the analysis of the accompanying photon bremsstrahlung. We study the scattering
of $p + ^{208}{\rm Pb}$ at the proton incident energies of 140 and 145~MeV, and
the scattering of $p + ^{12}{\rm C}$, $p + ^{58}{\rm Ni}$, $p + ^{107}{\rm Ag}$
and $p + ^{197}{\rm Au}$ at the proton incident energy of 190~MeV. The model
determines contributions of the coherent emission (formed by an interaction
between the scattering proton and nucleus as a whole without the internal
many-nucleon structure), incoherent emission (formed by interactions between
the scattering proton and nucleus with the internal many-nucleon structure),
and transition between them in dependence on the photon energy. The
radius-parameter of the proton-nucleus potential for these reactions is
extracted from the experimental bremsstrahlung data analysis. We explain the
hump-shaped plateau in the intermediate- and high-energy regions of the spectra
by the essential presence of the incoherent emission, while at low energies the
coherent emission predominates which produces the logarithmic shape spectrum.
We provide our predictions (in absolute scale) for the angular distribution of
the bremsstrahlung photons in order to test our model, results and analysis in
further experiments.


title: Fluid-Based Analysis of Pedestrian Crowd at Bottlenecks

abstract:
  In emergency egress crowd behavior critically affects egress efficiency and
public safety. By integrating psychological principles to Newtonian motion of
crowd, a fluid-based equation is derived in this paper to explore how energy in
different forms is balanced when pedestrian crowd pass through a bottleneck.
Such fluid-based analysis helps to bridge a gap among psychological findings,
pedestrian models and simulation results, and it further provides a new
perspective to understand how the faster-is-slower effect is caused and how
disastrous events (e.g., jamming) occur at a bottleneck passage.


title: Mixture of anisotropic fluids

abstract:
  The recently introduced approach describing coupled quark and gluon
anisotropic fluids is generalized to include explicitly the transitions between
quarks and gluons. We study the effects of such processes on the thermalization
rate of anisotropic systems. We find that the quark-gluon transitions may
enhance the overall thermalization rate in the cases where the initial momentum
anisotropies correspond to mixed oblate-prolate or prolate configurations. On
the other hand, no effect on the thermalization rate is found in the case of
oblate configurations. The observed regularities are connected with the
late-time behavior of the analyzed systems which is described either by the
exponential decay or the power law.


title: Taverna Mobile: Taverna workflows on Android

abstract:
  Researchers are often on the move, say at conferences or projects meetings,
and as workflows are becoming ubiquitous in the scientific process, having
access to scientific workflows from a mobile device would be a significant
advantage. We therefore have developed Taverna Mobile, an application for
Android phones which allows browsing of existing workflows, executing them, and
reviewing the results.
  Taverna Mobile does not aim to reproduce the full experience of building
workflows in the Taverna Workbench, rather it focuses on tasks we have deemed
relevant to a scientist that is not at her desk. For instance, when visiting a
conference she might hear about someone's workflow, which she can quickly
locate and mark for later exploration. When in the biology lab, faced with
updated scientific data, the scientist can rerun her own workflow with new
inputs. While commuting, she can monitor the status of a long-running job.


title:
Training in Data Curation as Service in a Federated Data Infrastructure
  - the FrontOffice-BackOffice Model

abstract:
  The increasing volume and importance of research data leads to the emergence
of research data infrastructures in which data management plays an important
role. As a consequence, practices at digital archives and libraries change. In
this paper, we focus on a possible alliance between archives and libraries
around training activities in data curation. We introduce a so-called
\emph{FrontOffice--BackOffice model} and discuss experiences of its
implementation in the Netherlands. In this model, an efficient division of
tasks relies on a distributed infrastructure in which research institutions
(i.e., universities) use centralized storage and data curation services
provided by national research data archives. The training activities are aimed
at information professionals working at those research institutions, for
instance as digital librarians. We describe our experiences with the course
\emph{DataIntelligence4Librarians}. Eventually, we reflect about the
international dimension of education and training around data curation and
stewardship.


title:
Empirical Performance Evaluation of Enhanced Throughput Schemes of
  IEEE802.11 Technology in Wireless Area Networks

abstract:
  The success in the growing wireless standards can be measured by the
achievement of quality of service (QoS) specifications by the designers. The
IEEE802.11 wireless standards are widely accepted as wireless technology for
wireless LAN. Efforts have been made over the years by the task group to
provide adequate number of QoS enhancement schemes for the increasing numbers
of multimedia applications. This paper examines the empirical performances of
ad hoc wireless networks deployed on IEEE802.11 standard variants. A survey to
some of the QoS schemes incorporated in IEEE802.11 wireless PHY layers were
carried out. Then the effects of this enhancement schemes in relation to data
throughput and system capacity and reliability in the newest technology
deployed on IEEE802.11ac standards was investigated using real time
applications and simulation based approaches.


title: Dynamical models and Galaxy surveys

abstract:
  Equilibrium dynamical models are essential tools for extracting science from
surveys of our Galaxy. We show how models can be tested with data from a survey
before the survey's selection function has been determined. We illustrate the
application of this method by presenting some results for the RAVE survey. We
extend our published analytic distribution functions to include chemistry and
fit the chosen functional form to a combination of the Geneva--Copenhagen
survey (GCS) and a sample of G-dwarfs observed at z~1.75 kpc by the SEGUE
survey. By including solid dynamics we are able to predict the contribution
that the thick disc/halo stars surveyed by SEGUE should make to the GCS survey.
We show that the measured [Fe/H] distribution from the GCS includes many fewer
stars at [Fe/H]<-0.6 than are predicted. The problem is more likely to lie in
discordant abundance scales than with incorrect dynamics.


title: The Symmetric Chiral Field Equation

abstract:
  The reduction problem of the chiral field equation on symmetric spaces is
studied. It is shown that the symmetric chiral field has infinitely many local
conservation laws. A recursive formula for these conservation laws is derived
and the first associated integral of motion are given explicitly. Furthermore,
the Zakharov-Mikhailov (inverse scattering) transform is used to derive
explicit formulas for the N-soliton solution on arbitrary diagonal background.
The solitons' properties and interactions are analyzed. Such solitons are
naturally related to gravitational solitons of Einstein's field equations, and
this result is used to clarify why the latter do not have fixed amplitude and
velocities (unlike `classical' solitons). Finally, it is proven that the
symmetric chiral field (matrix) equation is equivalent to a single scalar
equation, which in turn, is equivalent to the Sine-Gordon equation.


title:
Fano resonances of microwave structures with embedded magneto-dipolar
  quantum dots

abstract:
  Long range dipole-dipole correlation in a ferromagnetic sample can be treated
in terms of collective excitations of the system as a whole. Ferrite samples
with linear dimensions smaller than the dephasing length, but still much larger
than the exchange-interaction scales are mesoscopic structures. Recently, it
was shown that mesoscopic quasi-2D ferrite disks, distinguishing by
multiresonance magneto-dipolar-mode (MDM) spectra, demonstrate unique
properties of artificial atomic structures: energy eigenstates, eigen
power-flow vortices and eigen helicity parameters. Because of these properties,
MDMs in a ferrite disk enable the confinement of microwave radiation to
subwavelength scales. In microwave structures with embedded MDM ferrite
samples, one can observe quantized fields with topologically distinctive
characteristics. The use of a quasi-2D ferrite-disk scatterer with internal MDM
resonance spectra along the channel propagation direction could change the
transmission dramatically. In this paper, we show that interaction of the MDM
ferrite particle with its environment has a deep analogy with the
Fano-resonance interference observed in natural and artificial atomic
structures. We characterize the observed effect as Fano-resonance interference
in MDM quantum dots.


title:
A characterisation of indecomposable web-modules over Khovanov-Kuperberg
  Algebras

abstract:
  After shortly recalling the construction of the Khovanov-Kuperberg algebras,
we give a characterisation of indecomposable web-modules. It says that a
web-module is indecomposable if and only if one can deduce it directly from the
Kuperberg bracket (via a Schur lemma argument). The proofs relies on the
construction of idempotents given by explicit foams. These foams are encoded by
combinatorial data called red graphs. The key point is to show that when, for a
web $w$ the Schur lemma does not apply, one can find an appropriate red graph
for $w$.


title: Dynamics for Galactic Archaeology

abstract:
  Our Galaxy is a complex machine in which several processes operate
simultaneously: metal-poor gas is accreted, is chemically enriched by dying
stars, and then drifts inwards, surrendering its angular momentum to stars; new
stars are formed on nearly circular orbits in the equatorial plane and then
diffuse through orbit space to eccentric and inclined orbits; the central
stellar bar surrenders angular momentum to the surrounding disc and dark halo
while acquiring angular momentum from inspiralling gas; the outer parts of the
disc are constantly disturbed by satellite objects, both luminous and dark, as
they sweep through pericentre. We review the conceptual tools required to bring
these complex happenings into focus. Our first concern must be the construction
of equilibrium models of the Galaxy, for upon these hang our hopes of
determining the Galaxy's mean gravitational field, which is required for every
subsequent step. Ideally our equilibrium model should be formulated so that the
secular evolution of the system can be modelled with perturbation theory. Such
theory can be used to understand how stars diffuse through orbit space from
either the thin gas disc in which we presume disc stars formed, or the debris
of an accreted object, the presumed origin of many halo stars. Coupling this
understanding to the still very uncertain predictions of the theory of stellar
evolution and nucleosynthesis, we can finally extract a complete model of the
chemodynamic evolution of our reasonably generic Galaxy. We discuss the
relation of such a model to cosmological simulations of galaxy formation, which
provide general guidance but cannot be relied on for quantitative detail.


title:
Note on a double binomial sum relevant to the Hadamard maximal
  determinant problem

abstract:
  We prove a double binomial sum identity which differs from most binomial sum
identities in that the summands involve the absolute value function. The
identity is of interest because it can be used in proofs of lower bounds for
the Hadamard maximal determinant problem. Our proof of the identity uses a
two-variable variant of the method of telescoping sums.


title:
Decision Trees for Function Evaluation - Simultaneous Optimization of
  Worst and Expected Cost

abstract:
  In several applications of automatic diagnosis and active learning a central
problem is the evaluation of a discrete function by adaptively querying the
values of its variables until the values read uniquely determine the value of
the function. In general, the process of reading the value of a variable might
involve some cost, computational or even a fee to be paid for the experiment
required for obtaining the value. This cost should be taken into account when
deciding the next variable to read. The goal is to design a strategy for
evaluating the function incurring little cost (in the worst case or in
expectation according to a prior distribution on the possible variables'
assignments). Our algorithm builds a strategy (decision tree) which attains a
logarithmic approxima- tion simultaneously for the expected and worst cost
spent. This is best possible under the assumption that $P \neq NP.$


title: Revealing the intricate effect of collaboration on innovation

abstract:
  We study the Japan and U.S. patent records of several decades to demonstrate
the effect of collaboration on innovation. We find that statistically inventor
teams slightly outperform solo inventors while company teams perform equally
well as solo companies. By tracking the performance record of individual teams
we find that inventor teams' performance generally degrades with more repeat
collaborations. Though company teams' performance displays strongly bursty
behavior, long-term collaboration does not significantly help innovation at
all. To systematically study the effect of repeat collaboration, we define the
repeat collaboration number of a team as the average number of collaborations
over all the teammate pairs. We find that mild repeat collaboration improves
the performance of Japanese inventor teams and U.S. company teams. Yet,
excessive repeat collaboration does not significantly help innovation at both
the inventor and company levels in both countries. To control for unobserved
heterogeneity, we perform a detailed regression analysis and the results are
consistent with our simple observations. The presented results reveal the
intricate effect of collaboration on innovation, which may also be observed in
other creative projects.

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


title: A semi-potential for finite and infinite sequential games

abstract:
  We consider a dynamical approach to game in extensive forms. By restricting
the convertibility relation over strategy profiles, we obtain a semi-potential
(in the sense of Kukushkin), and we show that in finite games the corresponding
restriction of better-response dynamics will converge to a Nash equilibrium in
quadratic (finite) time. Convergence happens on a per-player basis, and even in
the presence of players with cyclic preferences, the players with acyclic
preferences will stabilize. Thus, we obtain a candidate notion for rationality
in the presence of irrational agents. Moreover, the restriction of
convertibility can be justified by a conservative updating of beliefs about the
other players strategies.
  For infinite games in extensive form we can retain convergence to a Nash
equilibrium (in some sense), if the preferences are given by continuous payoff
functions; or obtain a transfinite convergence if the outcome sets of the game
are $\Delta^0_2$-sets.


title:
A Comprehensive, Wide-Field Study of Pulsating Stars in the Carina Dwarf
  Spheroidal Galaxy

abstract:
  We report the detection of 388 pulsating variable stars (and some additional
miscellaneous variables) in the Carina dSph galaxy over an area covering the
full visible extent of the galaxy and extending a few times beyond its
photometric (King) tidal radius along the direction of its major axis. Included
in this total are 340 newly discovered dwarf Cepheids which are mostly located
~2.5 magnitudes below the horizontal branch and have very short periods (<0.1
days) typical of their class and consistent with their location on the upper
part of the extended main sequence of the younger populations of the galaxy.
Several extra-tidal dwarf cepheids were found in our survey up to a distance of
~1 degree from the center of Carina. Our sample also includes RR Lyrae stars
and anomalous Cepheids some of which were found outside the galaxy's tidal
radius as well. This supports past works that suggests Carina is undergoing
tidal disruption. We use the period-luminosity relationship for dwarf Cepheids
to estimate a distance modulus of 20.17 +/- 0.10 mags, in very good agreement
with the estimate from RR Lyrae stars. We find some important differences in
the properties of the dwarf Cepheids of Carina and those in Fornax and the LMC,
the only extragalactic samples of dwarf Cepheids currently known. These
differences may reflect a metallicity spread, depth along the line of sight
and/or, different evolutionary paths of the dwarf Cepheid stars.


title: Stable sets of primes in number fields

abstract:
  We define a new class of sets -- stable sets -- of primes in number fields.
For example, Chebotarev sets $P_{M/K}(\sigma)$, with $M/K$ Galois and $\sigma
\in \Gal(M/K)$, are very often stable. These sets have positive (but arbitrary
small) Dirichlet density and generalize sets with density 1 in the sense that
arithmetic theorems like certain Hasse principles, the Grunwald-Wang theorem,
the Riemann's existence theorem, etc. hold for them. Geometrically this allows
to give examples of infinite sets $S$ with arbitrary small positive density
such that $\Spec \mathcal{O}_{K,S}$ is algebraic $K(\pi,1)$ (for all $p$
simultaneous).


title: On some anabelian properties of arithmetic curves

abstract:
  In this paper we generalize an argument of Neukirch from birational anabelian
geometry to the case of arithmetic curves. In contrast to the function field
case, it seems to be more complicate to describe the position of decomposition
groups of points at the boundary of the scheme $\Spec \caO_{K,S}$, where $K$ is
a number field and $S$ a set of primes of $K$, intrinsically in terms of the
fundamental group. We prove that it is equivalent to give the following pieces
of information additionally with the fundamental group $\pi_1(\Spec
\caO_{K,S})$: the location of decomposition groups of boundary points inside
it, the $p$-part of the cyclotomic character, the number of points on the
boundary of all finite etale covers, etc. Under certain finiteness hypothesis
on Tate-Shafarevich groups with divisible coefficients, one can reconstruct all
this quantities from the fundamental group alone.


title:
What is Decidable about Partially Observable Markov Decision Processes
  with {\omega}-Regular Objectives

abstract:
  We consider partially observable Markov decision processes (POMDPs) with
{\omega}-regular conditions specified as parity objectives. The class of
{\omega}-regular languages extends regular languages to infinite strings and
provides a robust specification language to express all properties used in
verification, and parity objectives are canonical forms to express
{\omega}-regular conditions. The qualitative analysis problem given a POMDP and
a parity objective asks whether there is a strategy to ensure that the
objective is satis- fied with probability 1 (resp. positive probability). While
the qualitative analysis problems are known to be undecidable even for very
special cases of parity objectives, we establish decidability (with optimal
complexity) of the qualitative analysis problems for POMDPs with all parity
objectives under finite- memory strategies. We establish optimal (exponential)
memory bounds and EXPTIME-completeness of the qualitative analysis problems
under finite-memory strategies for POMDPs with parity objectives.


title:
Study of lower hybrid wave propagation in ionized gas by Hamiltonian
  theory

abstract:
  In order to find an approximate solution to the Vlasov-Maxwell equation
system describing the lower hybrid wave propagation in magnetic confined
plasmas, the use of the WKB method leads to the ray tracing equations. The
Hamiltonian character of the ray tracing equations is investigated analytically
and numerically in order to deduce the physical properties of the wave
propagating without absorption in the confined plasma. The consequences of the
Hamiltonian character of the equations on the travelling wave, in particular,
on the evolution of the parallel wavenumber along the propagation path have
been accounted and the chaotic diffusion of the timeaveraged parallel
wave-number towards higher values has been evaluated. Numerical analysis by
means of a Runge-Kutta based algorithm implemented in a ray tracing code
supplies the analytical considerations. A numerical tool based on the
symplectic integration of the ray trajectories has been developed.


title:
ALMA Observations of the IRDC Clump G34.43+00.24 MM3: Hot Core and
  Molecular Outflows

abstract:
  We have observed a cluster forming clump (MM3) associated with the infrared
dark cloud G34.43+00.24 in the 1.3 mm continuum and the CH3OH, CS, 13CS, SiO,
CH3CH2CN, and HCOOCH3 lines with the Atacama Large Millimeter/submillimeter
Array and in K-band with the Keck telescope. We have found a young outflow
toward the center of this clump in the SiO, CS, and CH3OH lines. This outflow
is likely driven by a protostar embedded in a hot core, which is traced by the
CH3CH2CN, HCOOCH3, 13CS, and high excitation CH3OH lines. The size of the hot
core is about 800 x 300 AU in spite of its low mass (<1.1 M_sun), suggesting a
high accretion rate or the presence of multiple star system harboring a few hot
corinos. The outflow is highly collimated, and the dynamical timescale is
estimated to be less than 740 yr. In addition, we have also detected extended
emission of SiO, CS, and CH3OH, which is not associated with the hot core and
the outflow. This emission may be related to past star formation activity in
the clump. Although G34.43+00.24 MM3 is surrounded by a dark feature in
infrared, it has already experienced active formation of low-mass stars in an
early stage of clump evolution.


title: Containing epidemic outbreaks by message-passing techniques

abstract:
  The problem of targeted network immunization can be defined as the one of
finding a subset of nodes in a network to immunize or vaccinate in order to
minimize a tradeoff between the cost of vaccination and the final (stationary)
expected infection under a given epidemic model. Although computing the
expected infection is a hard computational problem, simple and efficient
mean-field approximations have been put forward in the literature in recent
years. The optimization problem can be recast into a constrained one in which
the constraints enforce local mean-field equations describing the average
stationary state of the epidemic process. For a wide class of epidemic models,
including the susceptible-infected-removed and the
susceptible-infected-susceptible models, we define a message-passing approach
to network immunization that allows us to study the statistical properties of
epidemic outbreaks in the presence of immunized nodes as well as to find
(nearly) optimal immunization sets for a given choice of parameters and costs.
The algorithm scales linearly with the size of the graph and it can be made
efficient even on large networks. We compare its performance with topologically
based heuristics, greedy methods, and simulated annealing.

categories: physics.soc-ph cond-mat.dis-nn cs.SI q-bio.PE


title:
HYPERgeometric functions DIfferential REduction: MATHEMATICA based
  packages for differential reduction of generalized hypergeometric functions:
  Horn hypergeometric functions of two variables

abstract:
  HYPERDIRE is a project devoted to the creation of a set of Mathematica-based
programs for the differential reduction of hypergeometric functions. The
current version allows for manipulations involving the full set of Horn-type
hypergeometric functions of two variables, including 30 functions.


title:
Nonlinear coupled-mode theory for periodic plasmonic waveguides and
  metamaterials with loss and gain

abstract:
  We derive general coupled-mode equations describing the nonlinear interaction
of electromagnetic modes in media with loss and gain. Our approach is
rigorously based on the Lorentz reciprocity theorem, and it can be applied to a
broad range of metal-dielectric photonic structures, including plasmonic
waveguides and metamaterials. We verify that our general results agree with the
previous analysis of particular cases, and predict novel effects on self- and
cross-phase modulation in multi-layer nonlinear fishnet metamaterials.


title:
Majorana bound states in two-channel time-reversal-symmetric nanowire
  systems

abstract:
  We consider time-reversal-symmetric two-channel semiconducting quantum wires
proximity coupled to an s-wave superconductor. We analyze the requirements for
a nontrivial topological phase and find that necessary conditions are 1) the
determinant of the pairing matrix in channel space must be negative, 2)
inversion symmetry must be broken, and 3) the two channels must have different
spin-orbit couplings. The first condition can be implemented in semiconducting
nanowire systems where interactions suppress intra-channel pairing, while the
inversion symmetry can be broken by tuning the chemical potentials of the
channels. For the case of collinear spin-orbit directions, we find a general
expression for the topological invariant by block diagonalization into two
blocks with chiral symmetry only. By projection to the low-energy sector, we
solve for the zero modes explicitly and study the details of the gap closing,
which in the general case happens at finite momenta.


title: Theory of the STM detection of Wigner molecules in spin incoherent CNTs

abstract:
  The linear conductance of a carbon nanotube quantum dot in the Wigner
molecule regime, coupled to two scanning tunnel microscope tips is inspected.
Considering the high temperature regime, the nanotube quantum dot is described
by means of the spin-incoherent Luttinger liquid picture. The linear
conductance exhibits spatial oscillations induced by the presence of the
correlated, molecular electron state. A power-law scaling of the electron
density and of the conductance as a function of the interaction parameter are
found. They confirm local transport as a sensitive tool to investigate the
Wigner molecule. The double-tip setup allows to explore different transport
regimes with different shapes of the spatial modulation, all bringing
information about the Wigner molecule.


title:
Positive solutions of a class of semilinear equations with absorption
  and schr\"odinger equations

abstract:
  Several results about positive solutions -in a Lipschitz domain- of a
nonlinear elliptic equation in a general form $ \Delta u(x)-g(x,u(x))=0$ are
proved, extending thus some known facts in the case of $ g(x,t)=t^q$, $q>1$,
and a smooth domain. Our results include a characterization -in terms of a
natural capacity- of a (conditional) removability property, a characterization
of moderate solutions and of their boundary trace and a property relating
arbitrary positive solutions to moderate solutions. The proofs combine
techniques of non-linear p.d.e.\ with potential theoretic methods with respect
to linear Schr\"odinger equations. A general result describing the measures
that are diffuse with respect to certain capacities is also established and
used. The appendix by the first author provides classes of functions $g$ such
that the nonnegative solutions of $ \Delta u-g(.,u)=0$ has some "good"
properties which appear in the paper.


title:
Measurement of acoustic and anatomic changes in oral and maxillofacial
  surgery patients

abstract:
  We describe an arrangement for simultaneous recording of speech and geometry
of vocal tract in patients undergoing surgery involving this area. Experimental
design is considered from an articulatory phonetic point of view. The speech
and noise signals are recorded with an acoustic-electrical arrangement. The
vocal tract is simultaneously imaged with MRI. A MATLAB-based system controls
the timing of speech recording and MR image acquisition. The speech signals are
cleaned from acoustic MRI noise by a non-linear signal processing algorithm.
Finally, a vowel data set from pilot experiments is compared with validation
data from anechoic chamber as well as with Helmholtz resonances of the vocal
tract volume.


title: Large-scale Magnetic Structure Formation in 3D-MHD Turbulence

abstract:
  The inverse cascade of magnetic helicity in 3D-MHD turbulence is believed to
be one of the processes responsible for large scale magnetic structure
formation in astrophysical systems. In this work we present an exhaustive set
of high resolution direct numerical simulations (DNS) of both forced and
decaying 3D-MHD turbulence, to understand this structure formation process. It
is first shown that an inverse cascade of magnetic helicity in small-scale
driven turbulence does not necessarily generate coherent large-scale magnetic
structures. The observed large-scale magnetic field, in this case, is severely
perturbed by magnetic fluctuations generated by the small-scale forcing. In the
decaying case, coherent large-scale structure form similar to those observed
astronomically. Based on the numerical results the formation of large-scale
magnetic structures in some astrophysical systems, is suggested to be the
consequence of an initial forcing which imparts the necessary turbulent energy
into the system, which, after the forcing shuts off, decays to form the
large-scale structures. This idea is supported by representative examples e.g.
cluster of galaxies.


title:
Contact points and fractional singularities for semigroups of
  holomorphic self-maps in the unit disc

abstract:
  We study boundary singularities which can appear for infinitesimal generators
of one-parameter semigroups of holomorphic self-maps in the unit disc. We
introduce "regular" fractional singularities and characterize them in terms of
the behavior of the associated semigroups and Koenigs functions. We also
provide necessary and sufficient geometric criteria on the shape of the image
of the Koenigs function for having such singularities. In order to do this, we
study contact points of semigroups and prove that any contact (not fixed) point
of a one-parameter semigroup corresponds to a maximal arc on the boundary to
which the associated infinitesimal generator extends holomorphically as a
vector field tangent to this arc.


title: Coherent Control of the Waveforms of Recoilless Gamma-Photons

abstract:
  An efficient method to coherently control the waveforms of gamma-photons has
been proposed and experimentally realized. It is based on the resonant
interaction of gamma-photons with an ensemble of nuclei with modulated
frequency of the quantum transition. In particular, the temporal compression of
an individual gamma-photon into coherent ultrashort pulse train has been
demonstrated. The developed technique is expected to give a strong impetus on
emerging fields of coherent and quantum gamma-optics, providing a basis for
realization of the gamma-photon nuclear-ensemble interfaces and quantum
interference effects at the nuclear gamma-ray transitions.


title:
Effects of transverse electric fields on Landau subbands in bilayer
  zigzag graphene nanoribbons

abstract:
  The magnetoelectronic properties of quasi-one-dimensional zigzag graphene
nanoribbons are investigated by using the Peierls tight-binding model.
Quasi-Landau levels (QLLs), dispersionless Landau subbands within a certain
region of k-space, are resulted from the competition between magnetic and
quantum confinement effects. In bilayer system, the interlayer interactions
lead to two groups of QLLs, one occurring at the Fermi level and the other one
occurring at higher energies. Transverse electric fields are able to distort
energy spectrum, tilt two groups of QLLs and cause semiconductor-metal
transition. From the perspective of wave functions, the distribution of
electrons is explored, and the evolution of Landau states under the influence
of electric fields is clearly discussed. More interestingly, the band mixing
phenomena exhibited in the energy spectrum are related to the state mixing,
which can be apparently seen in the wave functions. The density of states,
which could be verified through surface inspections and optical experiments,
such as scanning tunneling spectroscopy and absorption spectroscopy, is
provided at last.


title:
Paraelectric and Ferroelectric States in a Model for Relaxor
  Ferroelectrics

abstract:
  We study the free energy landscape of a minimal model for relaxor
ferroelectrics. Using a variational method which includes leading correlations
beyond the mean-field approximation as well as disorder averaging at the level
of a simple replica theory, we find metastable paraelectric states with a
stability region that extends to zero temperature. The free energy of such
states exhibits an essential singularity for weak compositional disorder
pointing to their necessary occurrence. Ferroelectric states appear as local
minima in the free energy at high temperatures and become stable below a
coexistence temperature $T_c$. We calculate the phase diagram in the electric
field-temperature plane and find a coexistence line of the polar and non-polar
phases which ends at a critical point. First-order phase transitions are
induced for fields sufficiently large to cross the region of stability of the
metastable paraelectric phase. These polar and non-polar states have distinct
structure factors from those of conventional ferroelectrics. We use this
theoretical framework to compare and to gain physical understanding of various
experimental results in typical relaxors.


title: Physics of adherent cells

abstract:
  One of the most unique physical features of cell adhesion to external
surfaces is the active generation of mechanical force at the cell-material
interface. This includes pulling forces generated by contractile polymer
bundles and networks, and pushing forces generated by the polymerization of
polymer networks. These forces are transmitted to the substrate mainly by focal
adhesions, which are large, yet highly dynamic adhesion clusters. Tissue cells
use these forces to sense the physical properties of their environment and to
communicate with each other. The effect of forces is intricately linked to the
material properties of cells and their physical environment. Here a review is
given of recent progress in our understanding of the role of forces in cell
adhesion from the viewpoint of theoretical soft matter physics and in close
relation to the relevant experiments.


title:
Ultrafast charge separation in organic photovoltaics enhanced by charge
  delocalization and vibronically hot exciton dissociation

abstract:
  In organic photovoltaics, the mechanism by which free electrons and holes are
generated overcoming the Coulomb attraction is a currently much debated topic.
To elucidate this mechanism at a molecular level, we carried out a combined
electronic structure and quantum dynamical analysis that captures the
elementary events from the exciton dissociation to the free carrier generation
at polymer/fullerene donor-acceptor heterojunctions. Our calculations show that
experimentally observed efficient charge separations can be explained by a
combination of two effects: First, the delocalization of charges which
substantially reduces the Coulomb barrier, and second, the vibronically hot
nature of the charge transfer state which promotes charge dissociation beyond
the barrier. These effects facilitate an ultrafast charge separation even at
low-band-offset heterojunctions.


title:
Stochastic processes with random contexts: a characterization, and
  adaptive estimators for the transition probabilities

abstract:
  This paper introduces the concept of random context representations for the
transition probabilities of a finite-alphabet stochastic process. Processes
with these representations generalize context tree processes (a.k.a. variable
length Markov chains), and are proven to coincide with processes whose
transition probabilities are almost surely continuous functions of the
(infinite) past. This is similar to a classical result by Kalikow about
continuous transition probabilities. Existence and uniqueness of a minimal
random context representation are proven, and an estimator of the transition
probabilities based on this representation is shown to have very good "pastwise
adaptativity" properties. In particular, it achieves minimax performance, up to
logarithmic factors, for binary renewal processes with bounded $2+\gamma$
moments.


title: Brace Bar-Cobar Duality

abstract:
  Using Kadeishvili's formulas with appropriate signs, we show that the
classical cobar construction from coalgebras to algebras \Omega: CoAlg -> Alg
can be enhanced to a functor from Hopf algebras to E_2 algebras (for a certain
choice of E_2 operad) \Omega : HopfAlg -> E_2 Alg, which, unlike its classical
counterpart, is not strictly adjoint, but homotopically equivalent to the left
adjoint of the enhanced bar construction B: E_2 Alg -> HopfAlg studied by
Gerstenhaber--Voronov and Fresse.


title: The J-flow and stability

abstract:
  We study the J-flow from the point of view of an algebro-geometric stability
condition. In terms of this we give a lower bound for the natural associated
energy functional, and we show that the blowup behavior found by Fang-Lai is
reflected by the optimal destabilizer. Finally we prove a general existence
result on complex tori.


title:
Efficient additive Schwarz preconditioning for hypersingular integral
  equations on locally refined triangulations

abstract:
  For non-preconditioned Galerkin systems, the condition number grows with the
number of elements as well as the quotient of the maximal and the minimal
mesh-size. Therefore, reliable and effective numerical computations, in
particular on adaptively refined meshes, require the development of appropriate
preconditioners. We analyze and numerically compare multilevel additive Schwarz
preconditioners for hypersingular integral equations, where 2D and 3D as well
as closed boundaries and open screens are covered. The focus is on a new local
multilevel preconditioner which is optimal in the sense that the condition
number of the corresponding preconditioned system is independent of the number
of elements, the local mesh-size, and the number of refinement levels.


title:
Anomalous-hydrodynamic analysis of charge-dependent elliptic flow in
  heavy-ion collisions

abstract:
  Anomalous hydrodynamics is a low-energy effective theory that captures
effects of quantum anomalies. We develop a numerical code of anomalous
hydrodynamics and apply it to dynamics of heavy-ion collisions, where anomalous
transports are expected to occur. This is the first attempt to perform fully
non-linear numerical simulations of anomalous hydrodynamics. We discuss
implications of the simulations for possible experimental observations of
anomalous transport effects. From analyses of the charge-dependent elliptic
flow parameters ($v_2^\pm$) as a function of the net charge asymmetry $A_\pm$,
we find that the linear dependence of $\Delta v_2^\pm \equiv v_2^- - v_2^+$ on
the net charge asymmetry $A_\pm$ cannot be regarded as a robust signal of
anomalous transports, contrary to previous studies. We, however, find that the
intercept $\Delta v_2^\pm(A_\pm=0)$ is sensitive to anomalous transport
effects.


title: Pascal, Fermat et la g\'eom\'etrie du hasard

abstract:
  Ce m\'emoire r\'ealis\'e \`a l'IUFM de Cr\'eteil en 1998 sous la direction
d'Evelyne Barbin \'etudie l'histoire du d\'ebut du calcul des probabilit\'es.
Sources: correspondance entre Pascal et Fermat, et Trait\'e du triangle
arithm\'etique de Pascal.
  --
  This report undertaken at the IUFM de Cr\'eteil in 1998 under the direction
of Evelyne Barbin studies the birth of probability theory. Sources:
correspondence between Pascal and Fermat, and Pascal's "Treatise on
Arithmetical Triangle"


title:
A search for pulsations in short gamma-ray bursts to constrain their
  progenitors

abstract:
  We searched for periodic and quasiperiodic signal in the prompt emission of a
sample of 44 bright short gamma-ray bursts detected with Fermi/GBM, Swift/BAT,
and CGRO/BATSE. The aim was to look for the observational signature of
quasiperiodic jet precession which is expected from black hole-neutron star
mergers, but not from double neutron star systems. Thus, this kind of search
holds the key to identify the progenitor systems of short GRBs and, in the wait
for gravitational wave detection, represents the only direct way to constrain
the progenitors. We tailored our search to the nature of the expected signal by
properly stretching the observed light curves by an increasing factor with
time, after calibrating the technique on synthetic curves. In none of the GRBs
of our sample we found evidence for periodic or quasiperiodic signals. In
particular, for the 7 unambiguously short GRBs with best S/N we obtained
significant upper limits to the amplitude of the possible oscillations. This
result suggests that BH-NS systems do not dominate the population of short GRB
progenitors as described by the kinematic model of Stone, Loeb, & Berger
(2013).


title:
Discovery of a Quadruple Lens in CANDELS with a Record Lens Redshift
  z=1.53

abstract:
  Using spectroscopy from the Large Binocular Telescope and imaging from the
Hubble Space Telescope we discovered the first strong galaxy lens at z(lens)>1.
The lens has a secure photometric redshift of z=1.53+/-0.09 and the source is
spectroscopically confirmed at z=3.417. The Einstein radius (0.35"; 3.0 kpc)
encloses 7.6 x 10^10 Msol, with an upper limit on the dark matter fraction of
60%. The highly magnified (40x) source galaxy has a very small stellar mass
(~10^8 Msol) and shows an extremely strong [OIII]_5007A emission line (EW_0 ~
1000A) bolstering the evidence that intense starbursts among very low-mass
galaxies are common at high redshift.


title:
Geometrical aspects of quantum walks on random two-dimensional
  structures

abstract:
  We study the transport properties of continuous-time quantum walks (CTQW)
over finite two-dimensional structures with a given number of randomly placed
bonds and with different aspect ratios (AR). Here, we focus on the transport
from, say, the left side to the right side of the structure where absorbing
sites are placed. We do so by analyzing the long-time average of the survival
probability of CTQW. We compare the results to the classical continuous-time
random walk case (CTRW). For small AR (landscape configurations) we observe
only small differences between the quantum and the classical transport
properties, i.e., roughly the same number of bonds is needed to facilitate the
transport. However, with increasing AR (portrait configurations) a much larger
number of bonds is needed in the CTQW case than in the CTRW case. While for
CTRW the number of bonds needed decreases when going from small AR to large AR,
for CTRW this number is large for small AR, has a minimum for the square
configuration, and increases again for increasing AR. We corroborate our
findings for large AR by showing that the corresponding quantum eigenstates are
strongly localized in situations in which the transport is facilitated in the
CTRW case.

categories: quant-ph cond-mat.stat-mech cs.IT math.IT


title: Brillouin Optomechanics

abstract:
  We introduce the concept of Brillouin optomechanics, a phonon-photon
interaction process mediated by the electrostrictive force exerted by light on
dielectrics and the photoelastic scattering of light from an acoustic wave. We
first provide a review of the phenomenon and continue with the first
experiments where stimulated Brillouin optomechanical actuation was used in
microdevices, and spontaneous Brillouin cooling was demonstrated.


title: Collective behavior of penetrable self-propelled rods in two dimensions

abstract:
  Collective behavior of self-propelled particles is observed on a microscale
for swimmers such as sperm and bacteria as well as for protein filaments in
motility assays. The properties of such systems depend both on their
dimensionality and the interactions between their particles. We introduce a
model for self-propelled rods in two dimensions that interact via a
separation-shifted Lennard-Jones potential. Due to the finite potential
barrier, the rods are able to cross. This model allows us to efficiently
simulate systems of self-propelled rods that effectively move in two dimensions
but can occasionally escape to the third dimension in order to pass each other.
Our quasi-two-dimensional self-propelled particles describe a class of active
systems that encompasses microswimmers close to a wall and filaments propelled
on a substrate. Using Monte Carlo simulations, we first determine the
isotropic-nematic transition for passive rods. Using Brownian dynamics
simulations, we characterize cluster formation of self-propelled rods as a
function of propulsion strength, noise, and energy barrier. Contrary to rods
with an infinite potential barrier, an increase of the propulsion strength does
not only favor alignment but also effectively decreases the potential barrier
that prevents crossing of rods. We thus find a clustering window with a maximum
cluster size at medium propulsion strengths.

categories: cond-mat.soft cond-mat.stat-mech physics.bio-ph physics.comp-ph q-bio.CB


title:
Geometry of Compressible and Incompressible Quantum Hall States:
  Application to Anisotropic Composite Fermion Liquids

abstract:
  Haldane's geometrical description of fractional quantum Hall states is
generalized to compressible states. It is shown that anisotropy in the
composite fermion Fermi surface is a direct reflection of this intrinsic
geometry. A simple model is introduced in which the geometric parameter can be
obtained exactly from other parameters including electron mass anisotropy. Our
results compare favorably with recent measurements of anisotropy in composite
fermion Fermi surface [D. Kamburov, Y. Liu, M. Shayegan, L. N. Pfeiffer, K. W.
West, and K. W. Baldwin, Phys. Rev. Lett. 110, 206801 (2013)]. Broader
implications of our results are discussed.


title: On Calculating Square Roots in GF(p)

abstract:
  This article presents a new method for calculating square roots in GF(p) by
exponentiating in GF(p^3) or equivalently modulo irreducible cubic polynomials.
This algorithm is in some ways similar to the Cipolla-Lehmer algorithm which is
based on exponentiating in GF(p^2). Another less well known square root
algorithm based on quadratic sums is also given. In addition to this, several
conjectures about the output of this GF(p^3) square root algorithm are
mentioned.


title:
Energy-conserving methods for Hamiltonian Boundary Value Problems and
  applications in astrodynamics

abstract:
  We introduce new methods for the numerical solution of general Hamiltonian
boundary value problems. The main feature of the new formulae is to produce
numerical solutions along which the energy is precisely conserved, as is the
case with the analytical solution. We apply the methods to locate periodic
orbits in the circular restricted three body problem by using their energy
value rather than their pe- riod as input data. We also use the methods for
solving optimal transfer problems in astrodynamics.


title: FRW universe in the laboratory

abstract:
  We consider an expanding relativistic fluid with spherical symmetry as a
model for an analog FRW spacetime. In the framework of relativistic acoustic
geometry we demonstrate how to mimic an arbitrary FRW spacetime with positive,
zero or negative spatial curvature. In the Lagrangian description we show that
a particular FRW spacetime is obtained by choosing the appropriate potential.
We discuss several examples and in particular the analog de Sitter spacetime in
the coordinate representation with positive and negative spatial curvature.


title: A Geometric Model for Odd Differential K-theory

abstract:
  Odd $K$-theory has the interesting property that it admits an infinite number
of inequivalent differential refinements. In this paper we provide a bundle
theoretic model for odd differential $K$-theory using the caloron
correspondence and prove that this refinement is unique up to a unique natural
isomorphism. We characterise the odd Chern character and its transgression form
in terms of a connection and Higgs field and discuss some applications. Our
model can be seen as the odd counterpart to the Simons-Sullivan construction of
even differential $K$-theory. We use this model to prove a conjecture of
Tradler-Wilson-Zeinalian regarding a related differential extension of odd
$K$-theory


title:
On Limits and Colimits Of Comodules over a Coalgebra in a Tensor
  Category

abstract:
  We show that the category of comodules over a coassociative coalgebra in a
complete, cocomplete and well-powered category has limits and colimits under
additional assumptions.


title:
Characterization of Anomalous Pair Currents in Josephson Junction
  Networks

abstract:
  Measurements performed on superconductive networks shaped in the form of
planar graphs display anomalously large currents when specific branches are
biased. The temperature dependencies of these currents evidence that their
origin is due to Cooper pair hopping through the Josephson junctions connecting
the superconductive islands of the array. The experimental data are discussed
in terms of a theoretical model which predicts, for the system under
consideration, an inhomogeneous Cooper pair distribution on the superconductive
islands of the network.


title: Numerical Simulations of Heat Explosion With Convection In Porous Media

abstract:
  In this paper we study the interaction between natural convection and heat
explosion in porous media. The model consists of the heat equation with a
nonlinear source term describing heat production due to an exothermic chemical
reaction coupled with the Darcy law. Stationary and oscillating convection
regimes and oscillating heat explosion are observed. The models with
quasi-stationary and unstationary Darcy equation are compared.