title: Modeling of Item-Difficulty for Ontology-based MCQs

abstract:
  Multiple choice questions (MCQs) that can be generated from a domain ontology
can significantly reduce human effort & time required for authoring &
administering assessments in an e-Learning environment. Even though here are
various methods for generating MCQs from ontologies, methods for determining
the difficulty-levels of such MCQs are less explored. In this paper, we study
various aspects and factors that are involved in determining the
difficulty-score of an MCQ, and propose an ontology-based model for the
prediction. This model characterizes the difficulty values associated with the
stem and choice set of the MCQs, and describes a measure which combines both
the scores. Further more, the notion of assigning difficultly-scores based on
the skill level of the test taker is utilized for predicating difficulty-score
of a stem. We studied the effectiveness of the predicted difficulty-scores with
the help of a psychometric model from the Item Response Theory, by involving
real-students and domain experts. Our results show that, the predicated
difficulty-levels of the MCQs are having high correlation with their actual
difficulty-levels.


title:
Unconventional double-bended saturation of optical transmission in
  graphene due to many-particle interactions

abstract:
  We present a joint theory-experiment study on the transmission/absorption
saturation after ultrafast pulse excitation in graphene. We reveal an
unconventional double-bended saturation behavior: Both bendings separately
follow the standard saturation model exhibiting two saturation fluences,
however, the corresponding fluences differ by three orders of magnitude and
have different physical origin. Our results reveal that this new and unexpected
behavior can be ascribed to an interplay between fluence- and time-dependent
many-particle scattering processes and phase-space filling effects.


title: Magnetic fields during galaxy mergers

abstract:
  Galaxy mergers are expected to play a central role for the evolution of
galaxies, and may have a strong impact on their magnetic fields. We present the
first grid-based 3D magneto-hydrodynamical simulations investigating the
evolution of magnetic fields during merger events. For this purpose, we employ
a simplified model considering the merger event of magnetized gaseous disks in
the absence of stellar feedback and without a stellar or dark matter component.
We show that our model naturally leads to the production of two peaks in the
evolution of the average magnetic field strength within 5 kpc, within 25 kpc
and on scales in between 5 and 25 kpc. The latter is consistent with the peak
in the magnetic field strength reported by Drzazga et al. (2011) in a merger
sequence of observed galaxies. We show that the peak on the galactic scale and
in the outer regions is likely due to geometrical effects, as the core of one
galaxy enters the outskirts of the other one. In addition, there is a physical
enhancement of the magnetic field within the central ~5 kpc, reflecting the
enhancement in density due to efficient angular momentum transport. We conclude
that high-resolution observations of the central regions will be particularly
relevant to probe the evolution of magnetic field structures during merger
events.


title:
Neighborhood Features Help Detecting Non-Technical Losses in Big Data
  Sets

abstract:
  Electricity theft is a major problem around the world in both developed and
developing countries and may range up to 40% of the total electricity
distributed. More generally, electricity theft belongs to non-technical losses
(NTL), which are losses that occur during the distribution of electricity in
power grids. In this paper, we build features from the neighborhood of
customers. We first split the area in which the customers are located into
grids of different sizes. For each grid cell we then compute the proportion of
inspected customers and the proportion of NTL found among the inspected
customers. We then analyze the distributions of features generated and show why
they are useful to predict NTL. In addition, we compute features from the
consumption time series of customers. We also use master data features of
customers, such as their customer class and voltage of their connection. We
compute these features for a Big Data base of 31M meter readings, 700K
customers and 400K inspection results. We then use these features to train four
machine learning algorithms that are particularly suitable for Big Data sets
because of their parallelizable structure: logistic regression, k-nearest
neighbors, linear support vector machine and random forest. Using the
neighborhood features instead of only analyzing the time series has resulted in
appreciable results for Big Data sets for varying NTL proportions of 1%-90%.
This work can therefore be deployed to a wide range of different regions around
the world.


title: An operational measure for squeezing

abstract:
  We propose and analyse a mathematical measure for the amount of squeezing
contained in a continuous variable quantum state. We show that the proposed
measure operationally quantifies the minimal amount of squeezing needed to
prepare a given quantum state and that it can be regarded as a squeezing
analogue of the "entanglement of formation". We prove that the measure is
convex and superadditive and we provide analytic bounds as well as a numerical
convex optimisation algorithm for its computation. By example, we then show
that the amount of squeezing needed for the preparation of certain multi-mode
quantum states can be significantly lower than naive approaches suggest.


title:
Probabilistic inference of basic stellar parameters: application to
  flickering stars

abstract:
  The relations between observable stellar parameters are usually assumed to be
deterministic. That is, given an infinitely precise measurement of independent
variable, `$x$', and some model, the value of dependent variable, `$y$' can be
known exactly. In practise this assumption is rarely valid and intrinsic
stochasticity means that two stars with exactly the same `$x$', will have
slightly different `$y$'s. The relation between short-timescale brightness
fluctuations (flicker) of stars and both surface gravity and stellar density
are two such stochastic relations that have, until now, been treated as
deterministic ones. We recalibrate these relations in a probabilistic
framework, using Hierarchical Bayesian Modelling (HBM) to constrain the
intrinsic scatter in the relations. We find evidence for additional scatter in
the relationships, that cannot be accounted for by the observational
uncertainties alone. The scatter in surface gravity and stellar density does
not depend on flicker, suggesting that using flicker as a proxy for $\log g$
and $\rho_\star$ is equally valid for dwarf and giant stars, despite the fact
that the observational uncertainties tend to be larger for dwarfs.


title:
Attacking One-loop Multi-leg Feynman Integrals with the Loop-Tree
  Duality

abstract:
  We discuss briefly the first numerical implementation of the Loop-Tree
Duality (LTD) method. We apply the LTD method in order to calculate ultraviolet
and infrared finite multi-leg one-loop Feynman integrals. We attack scalar and
tensor integrals with up to six legs (hexagons). The LTD method shows an
excellent performance independently of the number of external legs.


title:
Corporate system of monitoring network informational resources based on
  agent-based approach

abstract:
  The paper provides a agent-based model, which describes distribution of
informative messages, containing links to informational resources in the
Internet. The results of modeling have been confirmed by studying a real
network of Twitter microblogs. The paper describes stages of building a
corporate system of monitoring network informational resources, the content of
which is determined by links in microblogs. The advantages of such approach are
set forth.


title: Tissus plats et feuilletages homog\`enes sur le plan projectif

abstract:
  The aim of this work is to study the foliations on the complex projective
plane with flat \textsc{Legendre} transform (dual web). We establish some
effective criteria for the flatness of the dual $d$-web of a homogeneous
foliation of degree $d$ and we describe some explicit examples. These results
allow us to show that up to automorphism of $\mathbb{P}^2$ there are $11$
homogeneous foliations of degree $3$ with flat dual web. We will see also that
it is possible, under certain assumptions, to bring the study of flatness of
the dual web of a general foliation to the homogeneous framework. We get some
classification results about foliations with non-degenerate singularities and
flat \textsc{Legendre} transform.


title: Athena Wide Field Imager Key Science Drivers

abstract:
  The Wide Field Imager (WFI) is one of two instruments for the Advanced
Telescope for High-ENergy Astrophysics (Athena). In this paper we summarise
three of the many key science objectives for the WFI - the formation and growth
of supermassive black holes, non-gravitational heating in clusters of galaxies,
and spin measurements of stellar mass black holes - and describe their
translation into the science requirements and ultimately instrument
requirements. The WFI will be designed to provide excellent point source
sensitivity and grasp for performing wide area surveys, surface brightness
sensitivity, survey power, and absolute temperature and density calibration for
in-depth studies of the outskirts of nearby clusters of galaxies and very good
high-count rate capability, throughput, and low pile-up, paired with very good
spectral resolution, for detailed explorations of bright Galactic compact
objects.


title:
Origin of the Characteristic X-ray Spectral Variations of IRAS
  13224$-$3809

abstract:
  The Narrow-line Seyfert 1 galaxy (NLS1) IRAS 13224$-$3809 is known to exhibit
significant X-ray spectral variation, a sharp spectral drop at $\sim$ 7 keV,
strong soft excess emission, and a hint of iron L-edge feature, which is very
similar to the NLS1 1H 0707$-$495. We have proposed the "Variable Double
Partial Covering (VDPC) model" to explain the energy spectra and spectral
variability of 1H 0707$-$495 (Mizumoto, Ebisawa and Sameshima 2014, PASJ, 66,
122). In this model, the observed flux/spectral variations below 10 keV within
a $\sim$day are primarily caused by change of the partial covering fraction of
patchy clouds composed by double absorption layers in the line of sight. In
this paper, we apply the VDPC model to IRAS 13224$-$3809. Consequently, we have
found that the VDPC model can explain the observed spectral variations of IRAS
13224$-$3809 in the 0.5$-$10 keV band. In particular, we can explain the
observed Root Mean Square (RMS) spectra (energy dependence of the fractional
flux variation) in the entire 0.5$-$10 keV band. In addition to the well-known
significant drop in the iron K-band, we have found intriguing iron L-peaks in
the RMS spectra when the iron L-edge is particularly deep. This feature, which
is also found in 1H 0707$-$495, is naturally explained with the VDPC model,
such that the RMS variations increase at the energies where optical depths of
the partial absorbers are large. The absorbers have a larger optical depth at
the iron L-edge than in the adjacent energy bands, thus a characteristic iron
L-peak appears. On the other hand, just below the iron K-edge, the optical
depth is the lowest and the RMS spectrum has a broad dip.


title: MDS-Coded Distributed Storage for Low Delay Wireless Content Delivery

abstract:
  We address the use of maximum distance separable (MDS) codes for distributed
storage (DS) to enable efficient content delivery in wireless networks. Content
is stored in a number of the mobile devices and can be retrieved from them
using device-to-device communication or, alternatively, from the base station
(BS). We derive an analytical expression for the download delay in the
hypothesis that the reliability state of the network is periodically restored.
Our analysis shows that MDS-coded DS can dramatically reduce the download time
with respect to the reference scenario where content is always downloaded from
the BS.


title: Upper Bounds for the Poincar\'e Recurrence Time in Quantum Mixed States

abstract:
  In this paper by using geometric techniques, we provide upper bounds for the
Poincar\'e recurrence time of a quantum mixed state with discrete spectrum of
energies. In the case of discrete but finite spectrum we obtain two type of
upper bounds; one of them depends on the uncertainty in the energy, and the
other depends only on the (finite) number of states. In the case of discrete
but non-finite spectrum we obtain in the same way two upper bounds defining the
number of relevant states according to an statistical measurement. These bounds
correspond to two different situations in the quantum recurrence process. The
first bound is a recurrence time estimation purely quantum, while the other
bound that is related with the number of relevant states survives in the
classical limit.


title:
Modelling Ordinal Responses with Uncertainty: a Hierarchical Marginal
  Model with Latent Uncertainty components

abstract:
  In responding to rating questions, an individual may give answers either
according to his/her knowledge/awareness or to his/her level of
indecision/uncertainty, typically driven by a response style. As ignoring this
dual behaviour may lead to misleading results, we define a multivariate model
for ordinal rating responses, by introducing, for every item, a binary latent
variable that discriminates aware from uncertain responses. Some independence
assumptions among latent and observable variables characterize the uncertain
behaviour and make the model easier to interpret. Uncertain responses are
modelled by specifying probability distributions that can depict different
response styles characterizing the uncertain raters. A marginal parametrization
allows a simple and direct interpretation of the parameters in terms of
association among aware responses and their dependence on explanatory factors.
The effectiveness of the proposed model is attested through an application to
real data and supported by a Monte Carlo study.


title:
Gravitational Waves from the Phase Transition of a Non-linearly Realised
  Electroweak Gauge Symmetry

abstract:
  Within the Standard Model with non-linearly realised electroweak symmetry,
the LHC Higgs boson may reside in a singlet representation of the gauge group.
Several new interactions are then allowed, including anomalous Higgs
self-couplings, which may drive the electroweak phase transition to be strongly
first-order. In this paper we investigate the cosmological electroweak phase
transition in a simplified model with an anomalous Higgs cubic self- coupling.
We look at the feasibility of detecting gravitational waves produced during
such a transition in the early universe by future space-based experiments. We
find that for the range of relatively large cubic couplings, $111~{\rm GeV}~
\lesssim |\kappa| \lesssim 118~{\rm GeV}$, $\sim $mHz frequency gravitational
waves can be observed by eLISA, while BBO will potentially be able to detect
waves in a wider frequency range, $0.1-10~$mHz.


title: Can Chameleon Field be identified with Quintessence ?

abstract:
  In the Einstein-Cartan gravitational theory with the chameleon field,
changing its mass in dependence of a density of its environment, we analyze the
Friedmann-Einstein equations for the Universe evolution with the expansion
parameter $a$ dependent on time only. We analyze the problem of an
identification of the chameleon field with quintessence, i.e. a canonical
scalar field responsible for dark energy dynamics and for the acceleration of
the Universe expansion. We show that since the cosmological constant, related
to the relic dark energy density, is induced by torsion (Astrophys. J.829, 47
(2016)), the chameleon field may, in principle, possess some properties of
quintessence such as an influence on the dark energy dynamics and the
acceleration of the Universe expansion even on the late-time acceleration, but
it cannot be identified with quintessence to full extent.


title:
A Mysterious Cluster Expansion Associated to the Expectation Value of
  the Permanent of 0-1 Matrices

abstract:
  We consider two ensembles of 0-1 nxn matrices. The first is the set of all
nxn matrices with entries zeroes and ones such that all column sums and all row
sums equal r, uniformly weighted. The second is the set of nxn matrices with
zero and one entries where the probability that any given entry is one is r/n,
the probabilities of the individual entries being i.i.d.'s. Calling the two
expectations E and E_B respectively, we develop a formal relation
  E(perm(A))=E_B(perm(A)) exp( sum T_i ) (A1)
  We use two well known approximating ensembles to E, E_1 and E_2. Replacing E
by either E_1 or E_2 we can evaluate all terms in (A1). For either E_1 or E_2
the T_i have amazing properties. We conjecture that all these properties also
hold for E. We carry through a similar development treating E(perm_m(A)), with
m proportional to n, in place of E(perm(A)).


title:
A graph-based algorithm for the multi-objective optimization of gene
  regulatory networks

abstract:
  The evolution of gene regulatory networks in variable environments poses
Multi-objective Optimization Problem (MOP), where the expression levels of
genes must be tuned to meet the demands of each environment. When formalized in
the context of monotone systems, this problem falls into a sub-class of linear
MOPs. Here, the constraints are partial orders and the objectives consist of
either the minimization or maximization of single variables, but their number
can be very large. To efficiently and exhaustively find Pareto optimal
solutions, we introduce a mapping between coloured Hasse diagrams and polytopes
associated with an ideal point. A dynamic program based on edge contractions
yields an exact closed-form description of the Pareto optimal set, in
polynomial time of the number of objectives relative to the number of faces of
the Pareto front. We additionnally discuss the special case of series-parallel
graphs with monochromatic connected components of bounded size, for which the
running time and the representation of solutions can in principle be linear in
the number of objectives.


title: Quasidynamical symmetries in the backbending of chromium isotopes

abstract:
  Background: Symmetries are a powerful way to characterize nuclear wave
functions. A true dynamical symmetry, where the Hamiltonian is block-diagonal
in subspaces defined by the group, is rare. More likely is a quasidynamical
symmetry: states with different quantum numbers (i.e. angular momentum)
nonetheless sharing similar group-theoretical decompositions. Purpose: We use
group-theoretical decomposition to investigate backbending, an abrupt change in
the moment of inertia along the yrast line, in $^{48,49,50}$Cr: prior
mean-field calculations of these nuclides suggest a change from strongly
prolate to more spherical configurations as one crosses the backbending and
increases in angular momentum. Methods: We decompose configuration-interaction
shell-model wavefunctions using the SU(2) groups $L$ (total orbital angular
momentum) and $S$ (total spin), and the groups SU(3) and SU(4). We do not need
a special basis but only matrix elements of Casimir operators, applied with a
modified Lanczos algorithm. Results: We find quasidynamical symmetries, albeit
often of a different character above and below the backbending, for each group.
While the strongest evolution was in SU(3), the decompositions did not suggest
a decrease in deformation. We point out with a simple example that mean-field
and SU(3) configurations may give very different pictures of deformation.
Conclusions: Persistent quasidynamical symmetries for several groups allow us
to identify the members of a band and to characterize how they evolve with
increasing angular momentum, especially before and after backbending.


title: Encoding Cryptographic Functions to SAT Using Transalg System

abstract:
  In this paper we propose the technology for constructing propositional
encodings of discrete functions. It is aimed at solving inversion problems of
considered functions using state-of-the-art SAT solvers. We implemented this
technology in the form of the software system called Transalg, and used it to
construct SAT encodings for a number of cryptanalysis problems. By applying SAT
solvers to these encodings we managed to invert several cryptographic
functions. In particular, we used the SAT encodings produced by Transalg to
construct the family of two-block MD5 collisions in which the first 10 bytes
are zeros. Also we used Transalg encoding for the widely known A5/1 keystream
generator to solve several dozen of its cryptanalysis instances in a
distributed computing environment. In the paper we compare in detail the
functionality of Transalg with that of similar software systems.


title:
Thermal entanglement and sharp specific-heat peak in an exactly solved
  spin-1/2 Ising-Heisenberg ladder with alternating Ising and Heisenberg
  inter-leg couplings

abstract:
  The spin-1/2 Ising-Heisenberg two-leg ladder accounting for alternating Ising
and Heisenberg inter-leg couplings in addition to the Ising intra-leg coupling
is rigorously mapped onto to a mixed spin-(3/2,1/2) Ising-Heisenberg diamond
chain with the nodal Ising spins $S=3/2$ and the interstitial spin-1/2
Heisenberg dimers. The latter effective model with higher-order interactions
between the nodal and interstitial spins is subsequently exactly solved within
the transfer-matrix method. The model under investigation exhibits five
different ground states: ferromagnetic, antiferromagnetic,
superantiferromagnetic and two types of frustrated ground states with a
non-zero residual entropy. A detailed study of thermodynamic properties reveals
an anomalous specific-heat peak at low enough temperatures, which is strongly
reminiscent because of its extraordinary height and sharpness to an anomaly
accompanying a phase transition. It is convincingly evidenced, however, that
the anomalous peak in the specific heat is finite and it comes from vigorous
thermal excitations from a two-fold degenerate ground state towards a
macroscopically degenerate excited state. Thermal entanglement between the
nearest-neighbor Heisenberg spins is also comprehensively explored by taking
advantage of the concurrence. The threshold temperature delimiting a boundary
between the entangled and disentangled parameter space may show presence of a
peculiar temperature reentrance.


title:
Citation score normalized by cited references (CSNCR): The introduction
  of a new citation impact indicator

abstract:
  In this paper, a new field-normalized indicator is introduced, which is
rooted in early insights in bibliometrics, and is compared with several
established field-normalized indicators (e.g. the mean normalized citation
score, MNCS, and indicators based on percentile approaches). Garfield (1979)
emphasizes that bare citation counts from different fields cannot be compared
for evaluative purposes, because the "citation potential" can vary
significantly between the fields. Garfield (1979) suggests that "the most
accurate measure of citation potential is the average number of references per
paper published in a given field". Based on this suggestion, the new indicator
is basically defined as follows: the citation count of a focal paper is divided
by the mean number of cited references in a field to normalize citations. The
new indicator is called citation score normalized by cited references (CSNCR).
The theoretical analysis of the CSNCR shows that it has the properties of
consistency and homogeneous normalization. The close relation of the new
indicator to the MNCS is discussed. The empirical comparison of the CSNCR with
other field-normalized indicators shows that it is slightly poorer able to
field-normalize citation counts than other cited-side normalized indicators
(e.g. the MNCS), but its results are favorable compared to two citing-side
indicator variants (SNCS indicators). Taken as a whole, the results of this
study confirm the ability of established indicators to field-normalize
citations.


title: Large scale quantum walks by means of optical fiber cavities

abstract:
  We demonstrate a platform for implementing quantum walks that overcomes many
of the barriers associated with photonic implementations. We use coupled
fiber-optic cavities to implement time-bin encoded walks in an integrated
system. We show that this platform can achieve very low losses combined with
high-fidelity operations, enabling an unprecedented large number of steps in a
passive system, as required for scenarios with multiple walkers. Furthermore
the platform is reconfigurable, enabling variation of the coin, and readily
extends to multidimensional lattices. We demonstrate variation of the coin bias
experimentally for three different values.


title:
Numerical analysis of homogeneous and inhomogeneous intermittent search
  strategies

abstract:
  A random search is a stochastic process representing the random motion of a
particle (denoted as the searcher) that is terminated when it reaches (detects)
a target particle or area the first time. In intermittent search the random
motion alternates between two or more motility modes, one of which is
non-detecting. An example is the slow diffusive motion as the detecting mode
and fast, directed ballistic motion as the non-detecting mode, which can lead
to much faster detection than a purely diffusive search. The transition rate
between the diffusive and the ballistic mode (and back) together with the
probability distribution of directions for the ballistic motion defines a
search strategy. If these transition rates and/or probability distributions
depend on the spatial coordinates within the search domain it is a spatially
inhomogeneous search strategy, if both are constant, it is a homogeneous one.
Here we study the efficiency, measured in terms of the mean first-passage time,
of spatially homogeneous and inhomogeneous search strategies for three
paradigmatic search problems: 1) the narrow escape problem, where the searcher
has to find a small area on the boundary of the search domain, 2) reaction
kinetics, which involves the detection of an immobile target in the interior of
a search domain, and 3) the reaction-escape problem, where the searcher first
needs to find a diffusive target before it can escape through a narrow region
on the boundary. Using families of spatially inhomogeneous search strategies,
partially motivated by the spatial organization of the cytoskeleton in living
cells with a centrosome, we show that they can be made almost always more
efficient than homogeneous strategies.


title: Differential tests for plurisubharmonic functions and Koch curves

abstract:
  We study minimum sets of singular plurisubharmonic functions and their
relation to upper contact sets. In particular we develop an algorithm checking
when a naturally parametrized curve is such a minimum set. The case of Koch
curves is studied in detail. We also study the size of the set of upper
non-contact points. We show that this set is always of Lebesgue measure zero
thus answering an open problem in the viscosity approach to the complex
Monge-Amp\`ere equation. Finally, we prove that similarly to the case of convex
functions, strictly plurisubharmonic lower tests yield existence of upper tests
with a control on the opening.


title: On the L^q Dimensions of Measures on Hueter-Lalley Type Self-Affine Sets

abstract:
  We study the L^q -dimensions of self-affine measures and the Kaenmaki measure
on a class of self-affine sets similar to the class considered by Hueter and
Lalley. We give simple, checkable conditions under which the Lq -dimensions are
equal to the value predicted by Falconer for a range of q. As a corollary this
gives a wider class of self-affine sets for which the Hausdorff dimension can
be explicitly calculated. Our proof combines the potential theoretic approach
developed by Hunt and Kaloshin with recent advances in the dynamics of
self-affine sets.


title: Ulrich bundles on surfaces with $q=p_g=0$

abstract:
  We prove that any surface with q=p_g=0 embedded by a sufficiently large
linear system admits a rank 2 Ulrich bundle. In particular every Enriques
surface admits a rank 2 Ulrich bundle.


title:
Low frequency estimation of continuous-time moving average L\'evy
  processes

abstract:
  In this paper we study the problem of statistical inference for a
continuous-time moving average L\'evy process of the form $$Z_{t} =
\int_{\mathbb{R}}\mathcal{K}(t-s)\, dL_{s},\quad t\in\mathbb{R}$$ with a
deterministic kernel (\K\) and a L{\'e}vy process (L\). Especially the
estimation of the L\'evy measure (\nu\) of $L$ from low-frequency observations
of the process $Z$ is considered. We construct a consistent estimator, derive
its convergence rates and illustrate its performance by a numerical example. On
the technical level, the main challenge is to establish a kind of exponential
mixing for continuous-time moving average L\'evy processes.


title:
Pre-DECIGO can get the smoking gun to decide the astrophysical or
  cosmological origin of GW150914-like binary black holes

abstract:
  Pre-DECIGO consists of three spacecraft arranged in an equilateral triangle
with 100km arm lengths orbiting 2000km above the surface of the earth. It is
hoped that the launch date will be in the late 2020s.
  Pre-DECIGO has one clear target: binary black holes (BBHs) like GW150914 and
GW151226. Pre-DECIGO can detect $\sim 30M_\odot-30M_\odot$ BBH mergers up to
redshift $z\sim 30$. The cumulative event rate is $\sim 1.8\times 10^{5}\,{\rm
events~yr^{-1}}$ in the Pop III origin model of BBHs like GW150914, and it
saturates at $z\sim 10$, while in the primordial BBH (PBBH) model, the
cumulative event rate is $ \sim 3\times 10^{4}\,{\rm events~ yr^{-1}}$ at
$z=30$ even if only $0.1\%$ of the dark matter consists of PBHs, and it is
still increasing at $z=30$. In the Pop I/II model of BBHs, the cumulative event
rate is $(3-10)\times10^{5}\,{\rm events~ yr^{-1}}$ and it saturates at $z \sim
6$. We present the requirements on orbit accuracy, drag free techniques, laser
power, frequency stability, and interferometer test mass. For BBHs like
GW150914 at 1Gpc, SNR$\sim 90$ is achieved with the definition of Pre-DECIGO in
the $0.01-100$Hz band. Pre-DECIGO can measure the mass spectrum and the
$z$-dependence of the merger rate to distinguish various models of BBHs like
GW150914.
  Pre-DECIGO can also predict the direction of BBHs at $z=0.1$ with an accuracy
of $\sim 0.3\,{\rm deg}^2$ and a merging time accuracy of $\sim 1$s at about a
day before the merger so that ground-based GW detectors further developed at
that time as well as electromagnetic follow-up observations can prepare for the
detection of merger in advance. For intermediate mass BBHs at a large redshift
$z > 10$, the QNM frequency after the merger can be within the Pre-DECIGO band
so that the ringing tail can also be detectable to confirm the Einstein theory
of general relativity with SNR$\sim 35$.
  [abridged]


title:
Finding binary active galactic nuclei candidates by the centroid shift
  in imaging surveys II. Testing the method with SDSS J233635.75-010733.7

abstract:
  In Liu (2015), we propose selecting binary active galactic nuclei (AGNs)
candidates using the centroid shift of the images, which is induced by the
non-synchronous variations of the two nuclei. In this paper, a known binary AGN
(SDSS J233635.75-010733.7) is employed to verify the ability of this method.
Using 162 exposures in the $R$ band of \textit{Palomar Transient Factory}
(PTF), an excess of dispersion in the positional distribution of the binary AGN
is detected, though the two nuclei cannot be resolved in the images of PTF. We
also propose a new method to compare the position of the binary AGN in PTF $g$
and $R$ band and find the difference is highly significant even only with 20
exposures. This new method is efficient for two nuclei with different spectral
energy distributions, e.g., type I + type II AGN or off-set AGN. Large-scale
surveys, e.g., the Panoramic Survey Telescope and Rapid Response System and the
Large Synoptic Survey Telescope, are expected to discover a large sample of
binary AGN candidates with these methods.


title:
Beam energy dependence and updated test of the Trojan horse nucleus
  invariance via the d(d,p)t measurement at ultra-low energies

abstract:
  The $\mathrm{^2H}(d,p)\mathrm{^3H}$ bare nucleus astrophysical S(E) factor
has been measured indirectly at energies from about 500 keV down to several keV
by means of the Trojan-horse method applied to the quasi-free process
$\mathrm{^2H({}^6Li},pt)\mathrm{^4He}$ induced at the lithium beam energy of 11
and 9.5 MeV, which makes the virtual binary process incident energy $\mathrm
{E}_{dd}^{qf}$ go much closer to the zero-quasi-free-energy point than that in
the previous similar experiment. The obtained results are compared with direct
data as well as with previous indirect investigation of the same binary
reactions. It shows that the precision of S(E) data in low energy range
extracted via the same Trojan horse nucleus ($\mathrm{^6Li}=(d \oplus \alpha)$
) becomes better when the incident energy decreases from high value down to the
zero-quasi-free-energy point. The very good agreement between data extracted
from different Trojan horse nucleus ($\mathrm{^6Li}=(d \oplus \alpha)$ vs.
$\mathrm{^3He}=(d \oplus p)$) gives a strong updated test for the independence
of the binary indirect cross section on the chosen Trojan horse nucleus at low
energies.


title:
Photoproduction of $J/\psi$ and $\Upsilon$ states in exclusive and
  proton-dissociative diffractive events

abstract:
  The amplitude for $\gamma p \to V p$, where $V$ is a $J/\psi$ or $\Upsilon$
ground state or excited vector meson, is calculated in a pQCD
$k_{T}$-factorization approach. We use this amplitude to predict the cross
section for exclusive photoproduction of $J/\psi, \psi', \Upsilon$ mesons in
proton-proton collisions. Calculations are performed for a variety of
unintegrated gluon distributions, and we compare our results to LHCb data. Here
we especially focus on the possibilty of constraining saturation effects.
Compared to earlier calculations we include both Dirac and Pauli
electromagnetic form factors. We discuss the role of the $Q\bar Q$ light-cone
wave functions for differential distributions for ratios such as
$\sigma(\psi')/\sigma(J/\psi)$. Absorption effects are always taken into
account.
  We also discuss the related diffractive production in proton dissociative
events. Here we concentrate on electromagnetic dissociation , which is
calculable without additional free parameters. Besides being of interest in
their own right, dissociative events constitute an important experimental
background to exclusive production.


title: Revealing the topology of quasicrystals with a diffraction experiment

abstract:
  Topological properties of crystals and quasicrystals is a subject of recent
and growing interest. This Letter reports an experiment where, for certain
quasicrystals, these properties can be directly retrieved from diffraction. We
directly observe, using an interferometric approach, all the topological
invariants of finite-length Fibonacci chains in their diffraction pattern. We
also demonstrate quantitatively the stability of these topological invariants
with respect to structural disorder.

categories: cond-mat.mes-hall cond-mat.mtrl-sci physics.optics quant-ph


title: An Hopf algebra for counting simple cycles

abstract:
  Simple cycles, also known as self-avoiding polygons, are cycles on graphs
which are not allowed to visit any vertex more than once. We present an exact
formula for enumerating the simple cycles of any length on any directed graph
involving a sum over its induced subgraphs. This result stems from an Hopf
algebra, which we construct explicitly, and which provides further means of
counting simple cycles. Finally, we obtain a more general theorem asserting
that any Lie idempotent can be used to enumerate simple cycles.


title:
Flaring Rates and the Evolution of Sunspot Group McIntosh
  Classifications

abstract:
  Sunspot groups are the main source of solar flares, with the energy to power
them being supplied by magnetic-field evolution (e.g. flux emergence or
twisting/shearing). To date, few studies have investigated the statistical
relation between sunspot-group evolution and flaring, with none considering
evolution in the McIntosh classification scheme. Here we present a statistical
analysis of sunspot groups from Solar Cycle 22, focusing on 24-hour changes in
the three McIntosh classification components. Evolution-dependent >C1.0, >M1.0,
and >X1.0 flaring rates are calculated, leading to the following results: (i)
flaring rates become increasingly higher for greater degrees of upward
evolution through the McIntosh classes, with the opposite found for downward
evolution; (ii) the highest flaring rates are found for upward evolution from
larger, more complex, classes (e.g. Zurich D- and E-classes evolving upward to
F-class produce >C1.0 rates of 2.66 +/- 0.28 and 2.31 +/- 0.09 flares per 24
hours, respectively); (iii) increasingly complex classes give higher rates for
all flare magnitudes, even when sunspot groups do not evolve over 24 hours.
These results support the hypothesis that injection of magnetic energy by flux
emergence (i.e. increasing in Zurich or compactness classes) leads to a higher
frequency and magnitude of flaring.


title: Diversity in Parametric Families of Number Fields

abstract:
  Let X be a projective curve defined over Q and t a non-constant Q-rational
function on X of degree at least 2. For every integer n pick a point P_n on X
such that t(P_n)=n. A result of Dvornicich and Zannier implies that, for large
N, among the number fields Q(P_1),...,Q(P_N) there are at least cN/\log N
distinct, where c>0. We prove that there are at least N/(\log N)^{1-c} distinct
fields, where c>0.


title:
Observing Custom Software Modifications: A Quantitative Approach of
  Tracking the Evolution of Patch Stacks

abstract:
  Modifications to open-source software (OSS) are often provided in the form of
"patch stacks" - sets of changes (patches) that modify a given body of source
code. Maintaining patch stacks over extended periods of time is problematic
when the underlying base project changes frequently. This necessitates a
continuous and engineering-intensive adaptation of the stack. Nonetheless,
long-term maintenance is an important problem for changes that are not
integrated into projects, for instance when they are controversial or only of
value to a limited group of users.
  We present and implement a methodology to systematically examine the temporal
evolution of patch stacks, track non-functional properties like integrability
and maintainability, and estimate the eventual economic and engineering effort
required to successfully develop and maintain patch stacks.
  Our results provide a basis for quantitative research on patch stacks,
including statistical analyses and other methods that lead to actionable advice
on the construction and long-term maintenance of custom extensions to OSS.


title: Monoids over which products of indecomposable acts are indecomposable

abstract:
  In this paper we prove that for a monoid $S$, products of indecomposable
right $S$-acts are indecomposable if and only if $S$ contains a right zero.
Besides, we prove that subacts of indecomposable right $S$-acts are
indecomposable if and only if $S$ is left reversible. Ultimately, we prove that
the one element right $S$-act $\Theta_S$ is product flat if and only if $S$
contains a left zero.


title:
From chiral d-wave to nodal line superconductivity in the harmonic
  honeycomb lattices

abstract:
  Motivated by the recent realization of the three-dimensional hyperhoneycomb
and stripyhoneycomb lattices in lithium iridate (Li$_2$IrO$_3$), we study the
possible spin-singlet superconducting states on the whole series of harmonic
honeycomb lattices. Beginning with an isolated out-of-plane twist making the
honeycomb lattice three-dimensional, we find that the chiral d$\pm$id state,
well-known from the honeycomb lattice, is realized in the largest members of
the series at low to intermediate doping. Along the twist, four chiral edge
states form a two-dimensional dispersive band. Reducing the distance between
the twists to form the smaller members of the harmonic honeycomb lattices, the
degeneracy between the d-wave states is lifted, which finally destroys the
chiral state. By analyzing the hyper- and stripyhoneycomb lattices and
generalizing using the $D_{2h}$ point group of all the harmonic honeycomb
lattices, we show that the superconducting state often belongs to the trivial
irreducible representation. This state has nodal lines at low to intermediate
doping, which is possible because the full lattice symmetry allows sign changes
between different sets of bonds. We also find time-reversal symmetry broken
states, which are either fully gapped or feature nodal points, in certain parts
of the phase diagram. Finally, we draw a comparison between the states
classified in terms of the $D_{2h}$ symmetries and those observed on the
$D_{6h}$ honeycomb lattice.


title: GPU Based Detection of Topological Changes in Voronoi Diagrams

abstract:
  The Voronoi diagrams are an important tool having theoretical and practical
applications in a large number of fields. We present a new procedure,
implemented as a set of CUDA kernels, which detects, in a general and efficient
way, topological changes in case of dynamic Voronoi diagrams whose generating
points move in time. The solution that we provide has been originally developed
to identify plastic events during simulations of soft-glassy materials based on
a Lattice Boltzmann model with frustrated-short range attractive and
mid/long-range repulsive-interactions. Along with the description of our
approach, we present also some preliminary physics results.


title: Enabling pulsar and fast transient searches using coherent dedispersion

abstract:
  We present an implementation of the coherent dedispersion algorithm capable
of dedispersing high-time-resolution radio observations to many different
dispersion measures (DMs). This approach allows the removal of the dispersive
effects of the interstellar medium and enables searches for pulsed emission
from pulsars and other millisecond-duration transients at low observing
frequencies and/or high DMs where time broadening of the signal due to
dispersive smearing would otherwise severely reduce the sensitivity. The
implementation, called 'cdmt', for Coherent Dispersion Measure Trials, exploits
the parallel processing capability of general-purpose graphics processing units
to accelerate the computations. We describe the coherent dedispersion algorithm
and detail how cdmt implements the algorithm to efficiently compute many
coherent DM trials. We present the concept of a semi-coherent dedispersion
search, where coherently dedispersed trials at coarsely separated DMs are
subsequently incoherently dedispersed at finer steps in DM. The software is
used in an ongoing LOFAR pilot survey to test the feasibility of performing
semi-coherent dedispersion searches for millisecond pulsars at 135MHz. This
pilot survey has led to the discovery of a radio millisecond pulsar -- the
first at these low frequencies. This is the first time that such a broad and
comprehensive search in DM-space has been done using coherent dedispersion, and
we argue that future low-frequency pulsar searches using this approach are both
scientifically compelling and feasible. Finally, we compare the performance of
cdmt with other available alternatives.


title: Big-Bounce cosmology in the presence of Immirzi field

abstract:
  The Immirzi parameter is promoted to be a scalar field and the Hamiltonian
analysis of the corresponding dynamical system is performed in the presence of
gravity. We identified some SU(2) connections, generalizing Ashtekar-Barbero
variables, and we rewrite the constraints in terms of them, setting the
classical formulation suitable for loop quantization. Then, we consider the
reduced system obtained when restricting to a flat isotropic cosmological
model. By mimicking loop quantization via an effective semiclassical treatment,
we outline how quantum effects are able to tame the initial singularity both in
synchronous time and when the Immirzi field is taken as a relational time.


title:
Measuring the Nonlinear Refractive Index of Graphene using the Optical
  Kerr Effect Method

abstract:
  By means of the ultrafast optical Kerr effect method coupled to optical
heterodyne detection (OHD-OKE), we characterize the third order nonlinear
response of graphene at telecom wavelength, and compare it to experimental
values obtained by the Z-scan method on the same samples. From these
measurements, we estimate a negative nonlinear refractive index for monolayer
graphene, $n_2 = - 1.1\times 10^{-13} m^2/W$. This is in contradiction to
previously reported values, which leads us to compare our experimental
measurements obtained by the OHD-OKE and the Z-scan method with theoretical and
experimental values found in the literature, and to discuss the discrepancies,
taking into account parameters such as doping.


title:
High-resolution HI and CO observations of high-latitude
  intermediate-velocity clouds

abstract:
  Intermediate-velocity clouds (IVCs) are HI halo clouds that are likely
related to a Galactic fountain process. In-falling IVCs are candidates for the
re-accretion of matter onto the Milky Way. We study the evolution of IVCs at
the disk-halo interface, focussing on the transition from atomic to molecular
IVCs. We compare an atomic IVC to a molecular IVC and characterise their
structural differences in order to investigate how molecular IVCs form high
above the Galactic plane. With high-resolution HI observations of the
Westerbork Synthesis Radio Telescope and 12CO(1-0) and 13CO(1-0) observations
with the IRAM 30m telescope, we analyse the small-scale structures within the
two clouds. By correlating HI and far-infrared (FIR) dust continuum emission
from the Planck satellite, the distribution of molecular hydrogen (H2) is
estimated. We conduct a detailed comparison of the HI, FIR, and CO data and
study variations of the $X_\rm{CO}$ conversion factor. The atomic IVC does not
disclose detectable CO emission. The atomic small-scale structure, as revealed
by the high-resolution HI data, shows low peak HI column densities and low HI
fluxes as compared to the molecular IVC. The molecular IVC exhibits a rich
molecular structure and most of the CO emission is observed at the eastern edge
of the cloud. There is observational evidence that the molecular IVC is in a
transient and, thus, non-equilibrium phase. The average $X_\rm{CO}$ factor is
close to the canonical value of the Milky Way disk. We propose that the two
IVCs represent different states in a gradual transition from atomic to
molecular clouds. The molecular IVC appears to be more condensed allowing the
formation of H2 and CO in shielded regions all over the cloud. Ram pressure may
accumulate gas and thus facilitate the formation of H2. We show evidence that
the atomic IVC will evolve also into a molecular IVC in a few Myr.


title: Superintelligence cannot be contained: Lessons from Computability Theory

abstract:
  Superintelligence is a hypothetical agent that possesses intelligence far
surpassing that of the brightest and most gifted human minds. In light of
recent advances in machine intelligence, a number of scientists, philosophers
and technologists have revived the discussion about the potential catastrophic
risks entailed by such an entity. In this article, we trace the origins and
development of the neo-fear of superintelligence, and some of the major
proposals for its containment. We argue that such containment is, in principle,
impossible, due to fundamental limits inherent to computing itself. Assuming
that a superintelligence will contain a program that includes all the programs
that can be executed by a universal Turing machine on input potentially as
complex as the state of the world, strict containment requires simulations of
such a program, something theoretically (and practically) infeasible.


title:
On the Dressing Factors, Bethe Equations and Yangian Symmetry of Strings
  on AdS3 x S3 x T4

abstract:
  Integrability is believed to underlie the AdS3/CFT2 correspondence with
sixteen supercharges. We elucidate the role of massless modes within this
integrable framework. Firstly, we find the dressing factors that enter the
massless and mixed-mass worldsheet S matrix. Secondly, we derive a set of
all-loop Bethe Equations for the closed strings, determine their symmetries and
weak-coupling limit. Thirdly, we investigate the underlying Yangian symmetry in
the massless sector and show that it fits into the general framework of Yangian
integrability. In addition, we compare our S matrix in the near-relativistic
limit with recent perturbative worldsheet calculations of Sundin and Wulff.


title:
Search for new physics in final states with two opposite-sign,
  same-flavor leptons, jets, and missing transverse momentum in pp collisions
  at sqrt(s) = 13 TeV

abstract:
  A search is presented for physics beyond the standard model in final states
with two opposite-sign, same-flavor leptons, jets, and missing transverse
momentum. The data sample corresponds to an integrated luminosity of 2.3
inverse femtobarns of proton-proton collisions at sqrt(s) = 13 TeV collected
with the CMS detector at the LHC in 2015. The analysis uses the invariant mass
of the lepton pair, searching for a kinematic edge or a resonant-like excess
compatible with the Z boson mass. Both search modes use several event
categories in order to increase the sensitivity to new physics. These
categories are based on the rapidity of the leptons, the multiplicity of jets
and b jets, the scalar sum of jet transverse momenta, and missing transverse
momentum. The observations in all signal regions are consistent with the
expectations from the standard model, and the results are interpreted in the
context of simplified models of supersymmetry.


title:
Pseudoscalar mesons in a finite cubic volume with twisted boundary
  conditions

abstract:
  We study the effects of a finite cubic volume with twisted boundary
conditions on pseudoscalar mesons. We first apply chiral perturbation theory in
the p-regime and calculate the corrections for masses, decay constants,
pseudoscalar coupling constants and form factors at next-to-leading order. We
show that the Feynman-Hellmann theorem and the relevant Ward-Takahashi identity
are satisfied. We then derive asymptotic formulae a la Luscher for twisted
boundary conditions. We show that chiral Ward identities for masses and decay
constants are satisfied by the asymptotic formulae in finite volume as a
consequence of infinite-volume Ward identities. Applying asymptotic formulae in
combination with chiral perturbation theory we estimate corrections beyond
next-to-leading order for twisted boundary conditions.


title: Deformation of Koszul algebras and the Duflo Isomorphism theorem

abstract:
  Let $\mathfrak g$ be a finite dimensional Lie algebra over a field $\mathbf
k$, $U\mathfrak g$ be its enveloping algebra and $S\mathfrak g$ be the
symmetric algebra on $\mathfrak g$. Extending the work of Braverman and
Gaitsgory on the deformation of Koszul algebras and the
Poincar{\'e}-Birkhoff-Witt theorem we obtain a generalized Duflo isomorphism
which is valid also over fields of finite characteristic:
$H_{\text{Lie}}^n(\mathfrak g, S\mathfrak g) \cong H_{\text{Hoch}}^n(U\mathfrak
g,U\mathfrak g)$ for all $n < \operatorname{char}\mathbf k$. This implies, in
particular, that Duflo's classic theorem, which is the special case in
characteristic zero of dimension zero, in fact holds in all characteristics and
the generalized theorem holds whenever $\dim \mathfrak g < \operatorname{char}
\mathbf k$.


title:
Spatially Coupled LDPC Codes Affected by a Single Random Burst of
  Erasures

abstract:
  Spatially-Coupled LDPC (SC-LDPC) ensembles achieve the capacity of binary
memoryless channels (BMS), asymptotically, under belief-propagation (BP)
decoding. In this paper, we study the BP decoding of these code ensembles over
a BMS channel and in the presence of a single random burst of erasures. We show
that in the limit of code length, codewords can be recovered successfully if
the length of the burst is smaller than some maximum recoverable burst length.
We observe that the maximum recoverable burst length is practically the same if
the transmission takes place over binary erasure channel or over binary
additive white Gaussian channel with the same capacity. Analyzing the stopping
sets, we also estimate the decoding failure probability (the error floor) when
the code length is finite.


title:
New simpler method of matching NLO corrections with parton shower Monte
  Carlo

abstract:
  Next steps in development of the KrkNLO method of implementing NLO QCD
corrections to hard processes in parton shower Monte Carlo programs are
presented. This new method is a simpler alternative to other well-known
approaches, such as MC@NLO and POWHEG. The KrkNLO method owns its simplicity to
the use of parton distribution functions (PDFs) in a new, so-called Monte Carlo
(MC), factorization scheme which was recently fully defined for the first time.
Preliminary numerical results for the Higgs-boson production process are also
presented.


title:
Going beyond k.p theory: a general method for obtaining effective
  Hamiltonians in both high and low symmetry situations

abstract:
  We provide a method for the generation of effective continuum Hamiltonians
that goes beyond the well known k.p method in being equally effective in both
high, and low (or no) symmetry situations. Our approach is based on a
surprising exact map of the two-centre tight-binding method onto a compact
continuum Hamiltonian, with a precise condition given for the hermiticity of
the latter object. We apply this method to a broad range of low dimensional
systems of both high and low symmetry: graphene, graphdiyne, {\gamma}-graphyne,
6,6,12-graphyne, twist bilayer graphene, and partial dislocation networks in
Bernal stacked bilayer graphene. For the single layer systems the method yields
Hamiltonians for the ideal lattices, as well as a systematic theory for
corrections due to deformation. In the case of bilayer graphene we provide a
compact expression for an effective field capable of describing any stacking
deformation of the bilayer; twist bilayer graphene, as well as the partial
dislocation network in AB stacked graphene, emerge as special cases of this
field. For the latter system we find (i) charge pooling on the mosaic of AB and
AC segments near the Dirac point and (ii) localized current carrying states on
the partials with the current density characterized by both intralayer and
interlayer components.


title: The Cohen Macaulay property for noncommutative rings

abstract:
  Let R be a noetherian ring which is a finite module over its centre Z(R).
This paper studies the consequences for R of the hypothesis that it is a
maximal Cohen Macaulay Z(R)-module. Old results are reviewed and a number of
new results are proved. The additional hypothesis of homological grade symmetry
is proposed as the appropriate extra lever needed to extend the classical
commutative homological hierarchy to this setting, and results are given
offering evidence in support of this proposal.


title:
Quantum entanglement of angular momentum states with quantum numbers up
  to 10010

abstract:
  Photons with a twisted phase front carry a quantized amount of orbital
angular momentum (OAM) and have become important in various fields of optics,
such as quantum and classical information science or optical tweezers. Because
no upper limit on the OAM content per photon is known, they are also
interesting systems to experimentally challenge quantum mechanical prediction
for high quantum numbers. Here, we take advantage of a recently developed
technique to imprint unprecedented high values of OAM, namely spiral phase
mirrors (SPM), to generate photons with more than 10,000 quanta of OAM.
Moreover, we demonstrate quantum entanglement between these large OAM quanta of
one photon and the polarization of its partner photon. To our knowledge, this
corresponds to entanglement with the largest quantum number that has been
demonstrated in an experiment. The results may also open novel ways to couple
single photons to massive objects, enhance angular resolution and highlight OAM
as a promising way to increase the information capacity of a single photon.


title:
Towards a new friction model for shallow water equations through an
  interactive viscous layer

abstract:
  The derivation of shallow water models from Navier-Stokes equations is
revisited yielding a class of two-layer shallow water models.An improved
velocity profile is proposed, based on the superposition of an ideal fluid and
a viscous layer inspired by the Interactive Boundary Layer interaction used in
aeronautics. This leads to a new friction law which depends not only on
velocity and depth but of the variations of velocity and thickness of boundary
layer. The resulting system is an extended shallow water model consisting of
three depth-integrated equations: the first two are mass and momentum
conservation in which a slight correction on hydrostatic pressure has been
made; the third one, known as von Karman equation, describes the evolution of
the viscous layer. This coupled model is shown to be conditionally hyperbolic,
and a Godunov-type finite volume scheme is also proposed. Several numerical
examples are provided and compared to the "Multi-Layer Saint-Venant" model.
They emphasize the ability of the model to deal with unsteady viscous effects.
They illustrate also the phase-lag between friction and topography, and even
recover possible reverse flows.


title:
SN 2012aa - a transient between Type Ibc core-collapse and superluminous
  supernovae

abstract:
  Context: Research on supernovae (SNe) over the past decade has confirmed that
there is a distinct class of events which are much more luminous (by $\sim2$
mag) than canonical core-collapse SNe (CCSNe). These events with visual peak
magnitudes $\lesssim-21$ are called superluminous SNe (SLSNe). Aims: There are
a few intermediate events which have luminosities between these two classes.
Here we study one such object, SN 2012aa. Methods: The optical photometric and
spectroscopic follow-up observations of the event were conducted over a time
span of about 120 days. Results: With V_abs at peak ~-20 mag, the SN is an
intermediate-luminosity transient between regular SNe Ibc and SLSNe. It also
exhibits an unusual secondary bump after the maximum in its light curve. We
interpret this as a manifestation of SN-shock interaction with the CSM. If we
would assume a $^{56}$Ni-powered ejecta, the bolometric light curve requires
roughly 1.3 M_sun of $^{56}$Ni and an ejected mass of ~14 M_sun. This would
also imply a high kinetic energy of the explosion, ~5.4$\times10^{51}$ ergs. On
the other hand, the unusually broad light curve along with the secondary peak
indicate the possibility of interaction with CSM. The third alternative is the
presence of a central engine releasing spin energy that eventually powers the
light curve over a long time. The host of the SN is a star-forming Sa/Sb/Sbc
galaxy. Conclusions: Although the spectral properties and velocity evolution of
SN 2012aa are comparable to those of normal SNe Ibc, its broad light curve
along with a large peak luminosity distinguish it from canonical CCSNe,
suggesting the event to be an intermediate-luminosity transient between CCSNe
and SLSNe at least in terms of peak luminosity. We argue that SN 2012aa belongs
to a subclass where CSM interaction plays a significant role in powering the
SN, at least during the initial stages of evolution.


title: Lepton Dipole Moments

abstract:
  Review of lepton dipole moments produced for the Physics In Collision 2015
conference.


title: Detection-dependent six-photon NOON state interference

abstract:
  NOON state interference (NOON-SI) is a powerful tool to improve the phase
sensing precision, and can play an important role in quantum sensing and
quantum imaging. However, most of the previous NOON-SI experiments only
investigated the center part of the interference pattern, while the full range
of the NOON-SI pattern has not yet been well explored.In this Letter, we
experimentally and theoretically demonstrate up to six-photon NOON-SI and study
the properties of the interference patterns over the full range.The
multi-photons were generated at a wavelength of 1584 nm from a PPKTP crystal in
a parametric down conversion process.It was found that the shape, the coherence
time and the visibility of the interference patterns were strongly dependent on
the detection schemes.This experiment can be used for applications which are
based on the envelope of the NOON-SI pattern, such as quantum spectroscopy and
quantum metrology.


title: Branching Random Walks on Binary Strings for Evolutionary Processes

abstract:
  In this article, we study branching random walks on graphs modeling
division-mutation processes inspired by adaptive immunity. We apply the theory
of expander graphs on mutation rules in evolutionary processes and obtain
estimates for the cover times of the branching random walks. This analysis
reveals an unexpected saturation phenomenon : increasing the mutation rate
above a certain threshold does not enhance the speed of state-space
exploration.


title:
A luminous hot accretion flow in the low-luminosity active galactic
  nucleus NGC 7213

abstract:
  The active galactic nucleus (AGN) NGC 7213 shows a complex correlation
between the monochromatic radio luminosity $L_R$ and the 2--10 keV X-ray
luminosity $L_X$, i.e. the correlation is unusually weak with $p\sim 0$ (in the
form $L_R\propto L_X^p$) when $L_X$ is below a critical luminosity, and steep
with $p>1$ when $L_X$ is above that luminosity. Such a hybrid correlation in
individual AGNs is unexpected as it deviates from the Fundamental Plane of AGN
activity. Interestingly, a similar correlation pattern is observed in the black
hole X-ray binary H1743--322, where it has been modelled by switching between
different modes of accretion. We propose that the flat $L_R$--$L_X$ correlation
of NGC 7213 is due to the presence of a luminous hot accretion flow, an
accretion model whose radiative efficiency is sensitive to the accretion rate.
Given the low luminosity of the source, $L_X\sim 10^{-4}$ of the Eddington
luminosity, the viscosity parameter is determined to be small, $\alpha\approx
0.01$. We also modelled the broad-band spectrum from radio to $\gamma$-rays,
the time lag between the radio and X-ray light curves, and the implied size and
the Lorentz factor of the radio jet. We predict that NGC 7213 will enter into a
two-phase accretion regime when $L_X > 1.5 \times 10^{42}\, {\rm erg\,s^{-1}}$.
When this happens, we predict a softening of the X-ray spectrum with the
increasing flux and a steep radio/X-ray correlation.


title: On the maximum principle for higher-order fractional Laplacians

abstract:
  We study existence, regularity, and qualitative properties of solutions to
linear problems involving higher-order fractional Laplacians $(-\Delta)^s$ for
any $s>1$. Using the nonlocal properties of these operators, we provide an
explicit counterexample to general maximum principles for $s\in(n,n+1)$ with
$n\in\mathbb N$ odd; moreover, using a representation formula for solutions, we
derive regularity and positivity preserving properties whenever the domain is
the whole space or a ball. In the case of the whole space we analyze the Riesz
kernel, which provides a fundamental solution, while in the case of the ball we
show the validity of Boggio's representation formula for all integer and
fractional powers of the Laplacian $s>0$. Our proofs rely on characterizations
of $s$-harmonic functions using higher-order Martin kernels, on a decomposition
of Boggio's formula, and on elliptic regularity theory.


title:
Orthogonal polynomial projection error measured in Sobolev norms in the
  unit ball

abstract:
  We study approximation properties of weighted $L^2$-orthogonal projectors
onto spaces of polynomials of bounded degree in the Euclidean unit ball, where
the weight is of the generalized Gegenbauer form $x \mapsto
(1-\|x\|^2)^\alpha$, $\alpha > -1$. Said properties are measured in
Sobolev-type norms in which the same weighted $L^2$ norm is used to control all
the involved weak derivatives. The method of proof does not rely on any
particular basis of orthogonal polynomials, which allows for a short,
streamlined and dimension-independent exposition.


title: Deletion Operations on Deterministic Families of Automata

abstract:
  Many different deletion operations are investigated applied to languages
accepted by one-way and two-way deterministic reversal-bounded multicounter
machines, deterministic pushdown automata, and finite automata. Operations
studied include the prefix, suffix, infix and outfix operations, as well as
left and right quotient with languages from different families. It is often
expected that language families defined from deterministic machines will not be
closed under deletion operations. However, here, it is shown that one-way
deterministic reversal-bounded multicounter languages are closed under right
quotient with languages from many different language families; even those
defined by nondeterministic machines such as the context-free languages. Also,
it is shown that when starting with one-way deterministic machines with one
counter that makes only one reversal, taking the left quotient with languages
from many different language families -- again including those defined by
nondeterministic machines such as the context-free languages -- yields only
one-way deterministic reversal-bounded multicounter languages (by increasing
the number of counters). However, if there are two more reversals on the
counter, or a second 1-reversal-bounded counter, taking the left quotient (or
even just the suffix operation) yields languages that can neither be accepted
by deterministic reversal-bounded multicounter machines, nor by 2-way
nondeterministic machines with one reversal-bounded counter.


title: Optimal Quantum Sample Complexity of Learning Algorithms

abstract:
  $ \newcommand{\eps}{\varepsilon} $In learning theory, the VC dimension of a
concept class $C$ is the most common way to measure its "richness." In the PAC
model $$ \Theta\Big(\frac{d}{\eps} + \frac{\log(1/\delta)}{\eps}\Big) $$
examples are necessary and sufficient for a learner to output, with probability
$1-\delta$, a hypothesis $h$ that is $\eps$-close to the target concept $c$. In
the related agnostic model, where the samples need not come from a $c\in C$, we
know that $$ \Theta\Big(\frac{d}{\eps^2} + \frac{\log(1/\delta)}{\eps^2}\Big)
$$ examples are necessary and sufficient to output an hypothesis $h\in C$ whose
error is at most $\eps$ worse than the best concept in $C$.
  Here we analyze quantum sample complexity, where each example is a coherent
quantum state. This model was introduced by Bshouty and Jackson, who showed
that quantum examples are more powerful than classical examples in some
fixed-distribution settings. However, Atici and Servedio, improved by Zhang,
showed that in the PAC setting, quantum examples cannot be much more powerful:
the required number of quantum examples is $$
\Omega\Big(\frac{d^{1-\eta}}{\eps} + d + \frac{\log(1/\delta)}{\eps}\Big)\mbox{
for all }\eta> 0. $$ Our main result is that quantum and classical sample
complexity are in fact equal up to constant factors in both the PAC and
agnostic models. We give two approaches. The first is a fairly simple
information-theoretic argument that yields the above two classical bounds and
yields the same bounds for quantum sample complexity up to a $\log(d/\eps)$
factor. We then give a second approach that avoids the log-factor loss, based
on analyzing the behavior of the "Pretty Good Measurement" on the quantum state
identification problems that correspond to learning. This shows classical and
quantum sample complexity are equal up to constant factors.


title: Degenerations of Hodge structure

abstract:
  Two interesting questions in algebraic geometry are: (i) how can a smooth
projective varieties degenerate? and (ii) given two such degenerations, when
can we say that one is "more singular/degenerate" than the other? Schmid's
Nilpotent Orbit Theorem yields Hodge-theoretic analogs of these questions, and
the Hodge-theoretic answers in turn provide insight into the motivating
algebro-geometric questions, sometimes with applications to the study of
moduli. Recently the Hodge-theoretic questions have been completely answered.
This is an expository survey of that work.


title:
A Multi-Game Framework for Harmonized LTE-U and WiFi Coexistence over
  Unlicensed Bands

abstract:
  The introduction of LTE over unlicensed bands (LTE-U) will enable LTE base
stations (BSs) to boost their capacity and offload their traffic by exploiting
the underused unlicensed bands. However, to reap the benefits of LTE-U, it is
necessary to address various new challenges associated with LTE-U and WiFi
coexistence. In particular, new resource management techniques must be
developed to optimize the usage of the network resources while handling the
interdependence between WiFi and LTE users and ensuring that WiFi users are not
jeopardized. To this end, in this paper, a new game theoretic tool, dubbed as
\emph{multi-game} framework is proposed as a promising approach for modeling
resource allocation problems in LTE-U. In such a framework, multiple,
co-existing and coupled games across heterogeneous channels can be formulated
to capture the specific characteristics of LTE-U. Such games can be of
different properties and types but their outcomes are largely interdependent.
After introducing the basics of the multi-game framework, two classes of
algorithms are outlined to achieve the new solution concepts of multi-games.
Simulation results are then conducted to show how such a multi-game can
effectively capture the specific properties of LTE-U and make of it a
"friendly" neighbor to WiFi.


title:
Shear piezoelectricity in poly(vinylidenefluoride-co-trifluoroethylene):
  full piezotensor coefficients by molecular modeling, biaxial transverse
  response, and use in suspended energy-harvesting nanostructures

abstract:
  The intrinsic flexible character of polymeric materials also causes
remarkable strain deformations along directions perpendicular to the applied
stress. Here the biaxial response in the shear piezoelectricity of
polyvinylidenefluoride copolymers is analyzed and their full piezoelectric
tensors are provided. The microscopic shear is exploited in single suspended
nanowires bent by localized loading to couple flexural deformation and
transverse piezoelectric response.


title:
XSHOOTER spectroscopy of the enigmatic planetary nebula Lin49 in the
  Small Magellanic Cloud

abstract:
  We performed a detailed spectroscopic analysis of the fullerene
C60-containing planetary nebula (PN) Lin49 in the Small Magellanic Cloud using
XSHOOTER at the ESO VLT and the Spitzer/IRS instruments. We derived nebular
abundances for nine elements. We used TLUSTY to derive photospheric parameters
for the central star. Lin49 is C-rich and metal-deficient PN (Z~0.0006). The
nebular abundances are in good agreement with Asymptotic Giant Branch
nucleosynthesis models for stars with initial mass 1.25 Msun and metallicity Z
= 0.001. Using the TLUSTY synthetic spectrum of the central star to define the
heating and ionising source, we constructed the photoionisation model with
CLOUDY that matches the observed spectral energy distribution (SED) and the
line fluxes in the UV to far-IR wavelength ranges simultaneously. We could not
fit the ~1-5 um SED using a model with 0.005-0.1 um-sized graphite grains and a
constant hydrogen density shell owing to the prominent near-IR excess, while at
other wavelengths the model fits the observed values reasonably well. We argue
that the near-IR excess might indicate either (1) the presence of very small
particles in the form of small carbon clusters, small graphite sheets, or
fullerene precursors, or (2) the presence of a high-density structure
surrounding the central star. We found that SMC C60 PNe show a near-IR excess
component to lesser or greater degree. This suggests that these C60 PNe might
maintain a structure nearby their central star.


title:
Temperature scaling of effective polaron mobility in energetically
  disordered media

abstract:
  We study effective mobility in 2 dimensional (2D) and 3 dimensional (3D)
systems, where hopping transitions of carriers are described by the Marcus
equation under a Gaussian density of states in the dilute limit. Using an
effective medium approximation (EMA), we determined the coefficient $C_d$ for
the effective mobility expressed by $\mu_{\rm
eff}\propto\exp\left[-\lambda/\left(4 k_{\rm B} T\right)-
C_d\sigma^2/\left(k_{\rm B} T\right)^2 \right]/\left[\sqrt{\lambda} (k_{\rm B}
T)^{3/2}\right]$, where $\lambda$ is the reorganization energy, $\sigma$ is the
standard deviation of the Gaussian density of states, and $k_{\rm B} T$ takes
its usual meaning. We found $C_d=1/2$ for both 2D and 3D. While various
estimates of the coefficient $C_d$ for 3D systems are available in the
literature, we provide for the first time the expected $C_d$ value for a 2D
system. By means of kinetic Monte-Carlo simulations, we show that the effective
mobility is well described by the equation shown above under certain conditions
on $\lambda$. We also give examples of analysis of experimental data for 2D and
3D systems based on our theoretical results.


title:
Estimation of the Regularization Parameter in Linear Discrete Ill-Posed
  Problems Using the Picard parameter

abstract:
  Accurate determination of the regularization parameter in inverse problems
still represents an analytical challenge, owing mainly to the considerable
difficulty to separate the unknown noise from the signal. We present a new
approach for determining the parameter for the general-form Tikhonov
regularization of linear ill-posed problems. In our approach the parameter is
found by approximate minimization of the distance between the unknown noiseless
data and the data reconstructed from the regularized solution. We approximate
this distance by employing the Picard parameter to separate the noise from the
data in the coordinate system of the generalized SVD. A simple and reliable
algorithm for the estimation of the Picard parameter enables accurate
implementation of the above procedure. We demonstrate the effectiveness of our
method on several numerical examples. A MATLAB-based implementation of the
proposed algorithms can be found at
https://www.weizmann.ac.il/condmat/superc/software/


title: Strong electron-phonon coupling in the sigma band of graphene

abstract:
  First-principles studies of the electron-phonon coupling in graphene predict
a high coupling strength for the $\sigma$ band with $\lambda$ values of up to
0.9. Near the top of the $\sigma$ band, $\lambda$ is found to be $\approx 0.7$.
This value is consistent with the recently observed kinks in the $\sigma$ band
dispersion by angle-resolved photoemission. While the photoemission intensity
from the $\sigma$ band is strongly influenced by matrix elements due to
sub-lattice interference, these effects differ significantly for data taken in
the first and neighboring Brillouin zones. This can be exploited to disentangle
the influence of matrix elements and electron-phonon coupling. A rigorous
analysis of the experimentally determined complex self-energy using
Kramers-Kronig transformations further supports the assignment of the observed
kinks to strong electron-phonon coupling and yields a coupling constant of
$0.6(1)$, in excellent agreement with the calculations.


title: Higher Galois for Segal Topos and Natural Phenomena

abstract:
  Toen and Vezzosi showed that $RHom^{geom}(T,lX)$ is a Segal groupoid, for $T$
a Segal topos, $lX = Loc(X)$ the Segal category of locally constant stacks on a
CW complex $X$. Taking the realization of such a groupoid defines a pro-object
$H_T = |RHom^{geom}(T, -)|$ that is defined to be the homotopy shape of the
topos $T$. What we do instead is fix a Segal topos $X$, we let $T$ vary, and
use the fact that $RHom^*_{Lex}(X,T) = RHom^{geom}(T,X)$ is a fundamental
$\infty$-groupoid. We then prove that $X$ is a localization of the Segal
category of local systems on $RHom^{geom}(T,X)$, in the spirit of Hoyois' work
in his "Higher Galois Theory" paper, where it is proved, morally, that local
systems on $H_T$ are equivalent to $T$ itself. We provide one application of
this formalism, regarding the Segal topos $X=dSt(k)$ of derived stacks, for $k$
a commutative ring, as corresponding to manifestations of natural laws,
themselves modeled by simplicial algebras, objects of $sk-CAlg$.


title: Speed limits in Liouville space for open quantum systems

abstract:
  One of the defining properties of an open quantum system is the variation of
its purity in time. We derive speed limits on the rate of purity change for
systems coupled to a Markovian environment. Our speed limits are based on
Liouville space where density matrices are represented as vectors. This
approach leads to speed limits that are always tighter compared to their
parallel speed limits in Hilbert space. These bounds depend solely on the
generators of the nonunitary dynamics and are independent of the particular
states of the systems. Thus, they are perfectly suited to investigate
dephasing, thermalization, and decorrelation processes of arbitrary states. We
show that our speed limits can be attained and are therefore tight. As an
application of our results we study correlation loss, and the speed of
classical and quantum correlation erasure in multi-particle system.


title:
On Artificial-Noise Aided Transmit Design for Multi-User MISO Systems
  with Integrated Services

abstract:
  This paper considers artificial noise (AN)-aided transmit designs for
multi-user MISO systems in the eyes of service integration. Specifically, we
combine two sorts of services, and serve them simultaneously: one multicast
message intended for all receivers and one confidential message intended for
only one receiver. The confidential message is kept perfectly secure from all
the unauthorized receivers. Our goal is to jointly design the optimal input
covariances for the multicast message, confidential message and AN, such that
the achievable secrecy rate region is maximized subject to the sum power
constraint. This secrecy rate region maximization (SRRM) problem is a nonconvex
vector maximization problem. To handle it, we reformulate the SRRM problem into
a provably equivalent scalar optimization problem and propose a searching
method to find all of its Pareto optimal points. The equivalent scalar
optimization problem is identified as a secrecy rate maximization (SRM) problem
with the quality of multicast service (QoMS) constraints. Further, we show that
this equivalent QoMS-constrained SRM problem, albeit nonconvex, can be
efficiently handled based on a two-stage optimization approach, including
solving a sequence of semidefinite programs. Moreover, we also extend the SRRM
problem to an imperfect channel state information (CSI) case where a worst-case
robust formulation is considered. In particular, while transmit beamforming is
generally a suboptimal technique to the SRRM problem, we prove that it is
optimal for the confidential message transmission whether in the perfect CSI
scenario or in the imperfect CSI scenario. Finally, numerical results
demonstrate that the AN-aided transmit designs are effective in expanding the
achievable secrecy rate regions.


title:
WISEP J060738.65+242953.4: A Nearby. Pole-On L8 Brown Dwarf with Radio
  Emission

abstract:
  We present a simultaneous, multi-wavelength campaign targeting the nearby
(7.2 pc) L8/L9 (optical/near-infrared) dwarf WISEP J060738.65+242953.4 in the
mid-infrared, radio, and optical. Spitzer Space Telescope observations show no
variability at the 0.2% level over 10 hours each in the 3.6 and 4.5 micron
bands. Kepler K2 monitoring over 36 days in Campaign 0 rules out stable
periodic signals in the optical with amplitudes great than 1.5% and periods
between 1.5 hours and 2 days. Non-simultaneous Gemini optical spectroscopy
detects lithium, constraining this L dwarf to be less than ~2 Gyr old, but no
Balmer emission is observed. The low measured projected rotation velocity (v
sin i < 6 km/s) and lack of variability are very unusual compared to other
brown dwarfs, and we argue that this substellar object is likely viewed
pole-on. We detect quiescent (non-bursting) radio emission with the VLA.
Amongst radio detected L and T dwarfs, it has the lowest observed L_nu and the
lowest v sin i. We discuss the implications of a pole-on detection for various
proposed radio emission scenarios.


title: Existence of traveling waves for the generalized FKPP equation

abstract:
  Variation in genotypes may be responsible for differences in dispersal rates,
directional biases, and growth rates of individuals. These traits may favor
certain genotypes and enhance their spatio-temporal spreading into areas
occupied by the less advantageous genotypes. We study how these factors
influence the speed of spreading in the case of two competing genotypes and
show that under the assumption of maintenance of spatially homogeneous total
population the dynamics of the frequency of one of the genotypes is
approximately described by the generalized
Fisher-Kolmogorov-Petrovskii-Piskunov (FKPP) equation. This generalized FKPP
equation with (nonlinear) frequency dependent diffusion and advection terms
admits traveling wave solutions (fronts/clines) that characterize the invasion
of the dominant genotype. Our existence results generalize the classical theory
for traveling waves for the FKPP with constant coefficients. Moreover for the
particular case of the quadratic (monostable) nonlinear growth-decay rate in
the generalized FKPP we study in details the influence of the variance in
diffusion and mean displacement rates of the two genotypes on the minimal wave
propagation speed.


title: Width, depth and space

abstract:
  The width measure treedepth, also known as vertex ranking, centered coloring
and elimination tree height, is a well-established notion which has recently
seen a resurgence of interest. Since graphs of bounded treedepth are more
restricted than graphs of bounded tree- or pathwidth, we are interested in the
algorithmic utility of this additional structure.
  On the negative side, we show that every dynamic programming algorithm on
treedepth decompositions of depth~$t$ cannot solve Dominating Set with
$O((3-\epsilon)^t \cdot \log n)$ space for any $\epsilon > 0$. This result
implies the same space lower bound for dynamic programming algorithms on tree
and path decompositions. We supplement this result by showing a space lower
bound of $O((3-\epsilon)^t \cdot \log n)$ for 3-Coloring and $O((2-\epsilon)^t
\cdot \log n)$ for Vertex Cover. This formalizes the common intuition that
dynamic programming algorithms on graph decompositions necessarily consume a
lot of space and complements known results of the time-complexity of problems
restricted to low-treewidth classes.
  We then show that treedepth lends itself to the design of branching
algorithms. This class of algorithms has in general distinct advantages over
dynamic programming algorithms: a) They use less space than algorithms based on
dynamic programming, b) they are easy to parallelize and c) they provide
possible solutions before terminating.
  Specifically, we design for Dominating Set a pure branching algorithm that
runs in time $t^{O(t^2)}\cdot n$ and uses space $O(t^3 \log t + t \log n)$ and
a hybrid of branching and dynamic programming that achieves a running time of
$O(3^t \log t \cdot n)$ while using $O(2^t t \log t + t \log n)$ space.
Algorithms for 3-Coloring and Vertex Cover with space complexity $O(t \cdot
\log n)$ and time complexity $O(3^t \cdot n)$ and $O(2^t\cdot n)$,
respectively, are included for completeness.


title: Direct Localization for Massive MIMO

abstract:
  Large-scale MIMO systems are well known for their advantages in
communications, but they also have the potential for providing very accurate
localization thanks to their high angular resolution. A difficult problem
arising indoors and outdoors is localizing users over multipath channels.
Localization based on angle of arrival (AOA) generally involves a two-step
procedure, where signals are first processed to obtain a user's AOA at
different base stations, followed by triangulation to determine the user's
position. In the presence of multipath, the performance of these methods is
greatly degraded due to the inability to correctly detect and/or estimate the
AOA of the line-of-sight (LOS) paths. To counter the limitations of this
two-step procedure which is inherently sub-optimal, we propose a direct
localization approach in which the position of a user is localized by jointly
processing the observations obtained at distributed massive MIMO base stations.
Our approach is based on a novel compressed sensing framework that exploits
channel properties to distinguish LOS from non-LOS signal paths, and leads to
improved performance results compared to previous existing methods.


title: Use of Jordan forms for convection-pressure split Euler solvers

abstract:
  In this study, we analyze convection-pressure split Euler flux functions
which contain genuine weakly hyperbolic convection subsystems. A system is said
to be a genuine weakly hyperbolic if all eigenvalues are real with no complete
set of linearly independent (LI) eigenvectors. To construct an upwind solver
based on flux difference splitting (FDS) framework, we require to generate
complete set of LI eigenvectors. This can be done through addition of
generalized eigenvectors which can be computed from theory of Jordan canonical
forms. Once we have complete set of LI generalized eigenvectors, we construct
upwind solvers in convection-pressure splitting framework. Since generalized
eigenvectors are not unique, we take extra care to ensure no direct
contribution of generalized eigenvectors in the final formulation of both the
newly developed numerical schemes. First scheme is based on Zha and Bilgen type
splitting approach, while second is based on Toro and V\'azquez splitting. Both
the schemes are tested on several bench-mark test problems on 1-D and one of
them is tested on some typical 2-D test problems which involve shock
instabilities. The concept of generalized eigenvector based on Jordan forms is
found to be useful in dealing with the genuine weakly hyperbolic parts of the
considered Euler systems.


title: Asymptotic expansions of Laplace integrals for quantum state tomography

abstract:
  Bayesian estimation of a mixed quantum state can be approximated via maximum
likelihood (MaxLike) estimation when the likelihood function is sharp around
its maximum. Such approximations rely on asymptotic expansions of
multi-dimensional Laplace integrals. When this maximum is on the boundary of
the integration domain, as it is the case when the MaxLike quantum state is not
full rank, such expansions are not standard. We provide here such expansions,
even when this maximum does not belong to the smooth part of the boundary, as
it is the case when the rank deficiency exceeds two. These expansions provide,
aside the MaxLike estimate of the quantum state, confidence intervals for any
observable. They confirm the formula proposed and used without precise
mathematical justifications by the authors in an article recently published in
Physical Review A.


title:
Duration of classicality in highly degenerate interacting Bosonic
  systems

abstract:
  We study sets of oscillators that have high quantum occupancy and that
interact by exchanging quanta. It is shown by analytical arguments and
numerical simulation that such systems obey classical equations of motion only
on time scales of order their relaxation time $\tau$ and not longer than that.
The results are relevant to the cosmology of axions and axion-like particles.

categories: hep-ph astro-ph.CO cond-mat.stat-mech hep-th


title: Full spectral testing of linear congruent method with a maximum period

abstract:
  In this paper the spectral analysis of all possible linear congruent
sequences with a maximum period is conducted and the best random number
generators are selected among them.


title:
Accretion of pristine gas and dilution during the formation of
  multiple-population globular clusters

abstract:
  We study the interaction of the early spherical GC wind powered by Type II
supernovae (SNe II) with the surrounding ambient medium consisting of the
gaseous disk of a star forming galaxy at redshift z ~> 2. The bubble formed by
the wind eventually breaks out of the disk, and most of the wind moves directly
out of the galaxy and is definitively lost. The fraction of the wind moving
nearly parallel to the galactic plane carves a hole in the disk which will
contract after the end of the SN activity. During the interval of time between
the end of the SN explosions and the "closure" of the hole, very O-poor stars
(the Extreme population) can form out of the super-AGB (asymptotic giant
branch) ejecta collected in the GC center. Once the hole contracts, the AGB
ejecta mix with the pristine gas, allowing the formation of stars with an
oxygen abundance intermediate between that of the very O-poor stars and that of
the pristine gas. We show that this mechanism may explain why Extreme
populations are present only in massive clusters, and can also produce a
correlation between the spread in helium and the cluster mass. Finally, we also
explore the possibility that our proposed mechanism can be extended to the case
of multiple populations showing bimodality in the iron content, with the
presence of two populations characterized by a small difference in [Fe/H]. Such
a result can be obtained taking into account the contribution of delayed SN II.


title:
Graph analysis of spontaneous brain network using EEG source
  connectivity

abstract:
  Exploring the human brain networks during rest is a topic of great interest.
Several structural and functional studies have previously been conducted to
study the intrinsic brain networks. In this paper, we focus on investigating
the human brain network topology using dense Electroencephalography (EEG)
source connectivity approach. We applied graph theoretical methods on
functional networks reconstructed from resting state data acquired using EEG in
14 healthy subjects. Our findings confirmed the existence of sets of brain
regions considered as functional hubs. In particular, the isthmus cingulate and
the orbitofrontal regions reveal high levels of integration. Results also
emphasize on the critical role of the default mode network (DMN) in enabling an
efficient communication between brain regions.


title:
Robustness of superconductivity to competing magnetic phases in
  tetragonal FeS

abstract:
  We have determined the superconducting and magnetic properties of a
hydrothermally synthesized powder sample of tetragonal FeS using muon spin
rotation ({\mu}SR). The superconducting properties are entirely consistent with
those of a recently published study, showing fully gapped behavior and giving a
penetration depth of {\lambda}_{ab} = 204(3) nm. However, our zero-field
{\mu}SR data are rather different and indicate the presence of a small,
non-superconducting magnetic phase within the sample. These results highlight
that sample-to-sample variations in magnetism can arise in hydrothermally
prepared phases, but interestingly the superconducting behavior is remarkably
insensitive to these variations.


title:
Infinite-dimensional reductive monoids associated to highest weight
  representations of Kac-Moody groups

abstract:
  Starting with a highest weight representation of a Kac-Moody group over the
complex numbers, we construct a monoid whose unit group is the image of the
Kac-Moody group under the representation, multiplied by the nonzero complex
numbers. We show that this monoid has similar properties to those of a
J-irreducible reductive linear algebraic monoid. In particular, the monoid is
unit regular and has a Bruhat decomposition, and the idempotent lattice of the
generalized Renner monoid of the Bruhat decomposition is isomorphic to the face
lattice of the convex hull of the Weyl group orbit of the highest weight.


title: Thermal Time and Kepler's Second Law

abstract:
  It is shown that a recent result regarding the average rate of evolution of a
dynamical system at equilibrium in combination with the quantization of
geometric areas coming from LQG, implies the validity of Kepler's Second Law of
planetary motion.


title: Dependence of dissipation on the initial distribution over states

abstract:
  We analyze how the amount of work dissipated by a fixed nonequilibrium
process depends on the initial distribution over states. Specifically, we
compare the amount of dissipation when the process is used with some specified
initial distribution to the minimal amount of dissipation possible for any
initial distribution. We show that the difference between those two amounts of
dissipation is given by a simple information-theoretic function that depends
only on the initial and final state distributions. Crucially, this difference
is independent of the details of the process relating those distributions. We
then consider how dissipation depends on the initial distribution for a
'computer', i.e., a nonequilibrium process whose dynamics over coarse-grained
macrostates implement some desired input-output map. We show that our results
still apply when stated in terms of distributions over the computer's
coarse-grained macrostates. This can be viewed as a novel thermodynamic cost of
computation, reflecting changes in the distribution over inputs rather than the
logical dynamics of the computation.


title:
Poisson stochastic process and basic Schauder and Sobolev estimates in
  the theory of parabolic equations

abstract:
  We show among other things how knowing Schauder or Sobolev-space estimates
for the one-dimensional heat equation allows one to derive their
multidimensional analogs for equations with coefficients depending only on time
variable with the {\em same\/} constants as in the case of the one-dimensional
heat equation. The method is based on using the Poisson stochastic process. It
looks like no other method is available at this time and it is a very
challenging problem to find a purely analytic approach to proving such results.


title:
Implications of $\delta^{CP}_l\sim 270^\circ$ and $\theta_{23}\gtrsim
  45^\circ$ for texture specific lepton mass matrices and $0\nu \beta \beta$
  decay

abstract:
  We study the phenomenological consequences of recent results from atmospheric
and accelerator neutrino experiments, favoring normal neutrino mass ordering
$m_1 < m_2 < m_3$, a near maximal lepton Dirac CP phase $\delta_{l}\sim
270^\circ$ along with $\theta_{23}\gtrsim 45^\circ$, for possible realization
of natural structure in the lepton mass matrices characterized by ${({M_{ij}})}
\sim O(\sqrt {{m_i}{m_j}}) $ for $i,j=1,2,3$. It is observed that deviations
from parallel texture structures for $M_{l}$ and $M_{\nu}$ are essential for
realizing such structures. In particular, such hierarchical neutrino mass
matrices are not supportive for a vanishing neutrino mass $m_{\nu 1}\rightarrow
0$ characterized by Det$M_{\nu}\ne 0$ and predict ${m_{\nu 1}} \simeq (0.1 -
8.0)$ $meV$ , ${m_{\nu 2}} \simeq (8.0 - 13.0)$ $meV$, ${m_{\nu 3}} \simeq
(47.0 - 52.0)$ $meV$, $\Sigma \simeq (56.0 - 71.0)$ $meV$ and $\left\langle
{{m_{ee}}} \right\rangle \simeq (0.01 - 10.0)$ $meV$, respectively, indicating
that the task of observing a $0\nu \beta \beta$ decay may be rather challenging
for near future experiments.


title:
Optimal Design of the Shiryaev-Roberts Chart: Give Your Shiryaev-Roberts
  a Headstart

abstract:
  We offer a numerical study of the effect of headstarting on the performance
of a Shiryaev-Roberts (SR) chart set up to control the mean of a normal
process. The study is a natural extension of that previously carried out by
Lucas and Crosier for the CUSUM scheme in their seminal 1982 paper published in
Technometrics. The Fast Initial Response (FIR) feature exhibited by a
headstarted CUSUM turns out to be also characteristic of an SR chart
(re-)started off a nonzero initial score. However, our main result is the
observation that a FIR SR with a carefully designed {\em optimal} headstart is
not just faster to react to an initial out-of-control situation, it is nearly
{\em the} fastest {\em uniformly}, i.e., assuming the process under
surveillance is equally likely to go out of control effective any sample
number. The performance improvement is the greater, the fainter the change. We
explain the optimization strategy, and tabulate the optimal initial score,
control limit, and the corresponding "worst possible" out-of-control Average
Run Length (ARL), considering mean-shifts of diverse magnitudes and a wide
range of levels of the in-control ARL.


title:
Coarse-grained depletion potentials for anisotropic colloids:
  application to lock-and-key systems

abstract:
  When a colloid is mixed with a depletant such as a non-adsorbing polymer, one
observes attractive effective interactions between the colloidal particles. If
these particles are anisotropic, analysis of these effective interactions is
challenging in general. We present a method for inference of approximate
(coarse-grained) effective interaction potentials between such anisotropic
particles. Using the example of indented (lock-and-key) colloids, we show how
numerical solutions can be used to integrate out the (hard sphere) depletant,
leading to a depletion potential that accurately characterises the effective
interactions. The accuracy of the method is based on matching of contributions
to the second virial coefficient of the colloids. The simplest version of our
method yields a piecewise-constant effective potential; we also show how this
scheme can be generalised to other functional forms, where appropriate.