title: Unruh effect for inertial observers through vacuum correlations

abstract:
  We study a dynamic version of the Unruh effect in a two dimensional collapse
model forming a black hole. In this two-dimensional collapse model a scalar
field coupled to the dilaton gravity, moving leftwards, collapses to form a
black hole. There are two sets of asymptotic ($t\to\infty$) observers, around
$x\to\infty$ and $x\to-\infty$. The observers at the right null infinity
witness a thermal flux of radiation associated with time dependent geometry
leading to a black hole formation and its subsequent Hawking evaporation, in an
expected manner. We show that even the observers at left null infinity find
themselves in thermal ambiance, without experiencing any change of spacetime
geometry all along their trajectories. They remain as inertial observers in a
\emph{flat} region of spacetime where curvature tensor identically vanishes in
a portion of full spacetime. These observers find the state of the quantum
field in a late time thermal configuration, with \emph{exactly the same}
temperature as measured by the observers at right null infinity, {\it despite
being inertial in flat spacetime region throughout their history}. This is very
closely related to the standard Unruh effect in the flat spacetime, except for
a key difference --- since they are inertial throughout and {\it have no
causally connected source in the past light cone to account for what they see}.
The result arises from quantum correlations which extend outside the past light
cone and is conceptually similar to the EPR correlations.


title: Towards a DSL for Perception-Based Safety Systems

abstract:
  This paper is an extension to an early presented programming language, called
a domain specific language. This paper extends the proposed concept with new
sensors and behaviours to address real-life situations. The functionality was
tested in lab experiments, and an extension to the earlier concepts is
proposed.


title:
Electronic transport in single-helical protein molecules: Effects of
  multiple charge conduction pathways and helical symmetry

abstract:
  We propose a tight-binding model to investigate electronic transport
properties of single helical protein molecules incorporating both the helical
symmetry and the possibility of multiple charge transfer pathways. Our study
reveals that due to existence of both the multiple charge transfer pathways and
helical symmetry, the transport properties are quite rigid under influence of
envi- ronmental fluctuations which indicates that these biomolecules can serve
as better alternatives in nanoelectronic devices than its other biological
counterparts e.g., single-stranded DNA.


title:
A quantum sensor: simultaneous precision gravimetry and magnetic
  gradiometry with a Bose-Einstein condensate

abstract:
  A Bose-Einstein condensate is used as an atomic source for a high precision
sensor. A $5\times 10^6$ atom F=1 spinor condensate of $^{87}$Rb is released
into free fall for up to $750$ms and probed with a Mach-Zehnder atom
interferometer based on Bragg transitions. The Bragg interferometer
simultaneously addresses the three magnetic states, $\left| m_f=1,0,-1
\right\rangle$, facilitating a simultaneous measurement of the acceleration due
to gravity with an asymptotic precision of $2.1\times 10^{-9}$$\Delta$g/g and
the magnetic field gradient to a precision $8$pT/m.


title:
Mercury (Hg) in meteorites: variations in abundance, thermal release
  profile, mass-dependent and mass-independent isotopic fractionation

abstract:
  We have measured the concentration, isotopic composition and thermal release
profiles of Mercury (Hg) in a suite of meteorites, including both chondrites
and achondrites. We find large variations in Hg concentration between different
meteorites (ca. 10 ppb to 14'000 ppb), with the highest concentration orders of
magnitude above the expected bulk solar system silicates value. From the
presence of several different Hg carrier phases in thermal release profiles
(150 to 650 {\deg}C), we argue that these variations are unlikely to be mainly
due to terrestrial contamination. The Hg abundance of meteorites shows no
correlation with petrographic type, or mass-dependent fractionation of Hg
isotopes. Most carbonaceous chondrites show mass-independent enrichments in the
odd-numbered isotopes 199Hg and 201Hg. We show that the enrichments are not
nucleosynthetic, as we do not find corresponding nucleosynthetic deficits of
196Hg. Instead, they can partially be explained by Hg evaporation and
redeposition during heating of asteroids from primordial radionuclides and
late-stage impact heating. Non-carbonaceous chondrites, most achondrites and
the Earth do not show these enrichments in vapor-phase Hg. All meteorites
studied here have however isotopically light Hg ({\delta}202Hg = ~-7 to -1)
relative to the Earth's average crustal values, which could suggest that the
Earth has lost a significant fraction of its primordial Hg. However, the late
accretion of carbonaceous chondritic material on the order of ~2%, which has
been suggested to account for the water, carbon, nitrogen and noble gas
inventories of the Earth, can also contribute most or all of the Earth's
current Hg budget. In this case, the isotopically heavy Hg of the Earth's crust
would have to be the result of isotopic fractionation between surface and
deep-Earth reservoirs.


title: Semi-homotopy and semi-fundamental groups

abstract:
  In this study we introduce the notions of semi-homotopy of semi-continuous
maps and of semi-paths. We also construct a group structure, which will be
called semi-fundamental group, using semi-loops and explore some properties of
semi-homotopy and semi-fundamental groups.


title: Emergence and Maintenance of Excitability: Kinetics over Structure

abstract:
  Emergence and maintenance of excitability is often phrased in terms of
arriving at and remaining about a manifold of 'solutions' embedded in a high
dimensional parameter space. Alongside studies that extend traditional focus on
control-based regulation of structural parameters (channel densities), there is
a budding interest in self-organization of kinetic parameters. In this picture,
ionic channels are continually forced by activity in-and-out of a large pool of
states not available for the mechanism of excitability. The process, acting on
expressed structure, provides a bed for generation of a spectrum of
excitability modes. Driven by microscopic fluctuations over a broad range of
temporal scales, self-organization of kinetic parameters extends the metaphors
and tools used in the study of development of excitability.


title: Suzaku observations of the hard X-ray spectrum of Vela Jr

abstract:
  We report the results of Suzaku observations of the young supernova remnant,
Vela Jr.\ (RX J0852.0$-$4622), which is known to emit synchrotron X-rays, as
well as TeV gamma-rays. Utilizing 39 Suzaku mapping observation data from Vela
Jr., a significant hard X-ray emission is detected with the hard X-ray detector
(HXD) from the north-west TeV-emitting region. The X-ray spectrum is well
reproduced by a single power-law model with the photon index of
3.15$^{+1.18}_{-1.14}$ in the 12--22 keV band. Compiling this with the soft
X-ray spectrum simultaneously observed with the X-ray imaging spectrometer
(XIS) onboard Suzaku, we find that the wide-band X-ray spectrum in the 2--22
keV band is reproduced with a single power-law or concave broken power-law
model, which are statistically consistent with each other. Whichever the model
of a single or broken power-law is appropriate, clearly the spectrum has no
rolloff structure. Applying this result to the method introduced in
\citet{yama2014}, we find that one-zone synchrotron model with electron
spectrum having a power-law plus exponential cutoff may not be applicable to
Vela Jr.


title:
Travelling-wave single-photon detectors integrated with diamond photonic
  circuits - operation at visible and telecom wavelengths with a timing jitter
  down to 23 ps

abstract:
  We report on the design, fabrication and measurement of travelling-wave
superconducting nanowire single-photon detectors (SNSPDs) integrated with
polycrystalline diamond photonic circuits. We analyze their performance both in
the near-infrared wavelength regime around 1600 nm and at 765 nm. Near-IR
detection is important for compatibility with the telecommunication
infrastructure, while operation in the visible wavelength range is relevant for
compatibility with the emission line of silicon vacancy centers in diamond
which can be used as efficient single-photon sources. Our detectors feature
high critical currents (up to 31 {\mu}A) and high performance in terms of
efficiency (up to 74% at 765 nm), noise-equivalent power (down to 4.4*10^-19
W/(Hz^1/2) at 765 nm) and timing jitter (down to 23 ps).

categories: physics.optics cond-mat.supr-con physics.ins-det quant-ph


title: #greysanatomy vs. #yankees: Demographics and Hashtag Use on Twitter

abstract:
  Demographics, in particular, gender, age, and race, are a key predictor of
human behavior. Despite the significant effect that demographics plays, most
scientific studies using online social media do not consider this factor,
mainly due to the lack of such information. In this work, we use
state-of-the-art face analysis software to infer gender, age, and race from
profile images of 350K Twitter users from New York. For the period from
November 1, 2014 to October 31, 2015, we study which hashtags are used by
different demographic groups. Though we find considerable overlap for the most
popular hashtags, there are also many group-specific hashtags.


title:
Resolving 4-D Nature of Magnetism with Depolarization and Faraday
  Tomography: Japanese SKA Cosmic Magnetism Science

abstract:
  Magnetic fields play essential roles in various astronomical objects. Radio
astronomy has revealed that magnetic fields are ubiquitous in our Universe.
However, the real origin and evolution of magnetic fields is poorly proven. In
order to advance our knowledge of cosmic magnetism in coming decades, the
Square Kilometre Array (SKA) should have supreme sensitivity than ever before,
which provides numerous observation points in the cosmic space. Furthermore,
the SKA should be designed to facilitate wideband polarimetry so as to allow us
to examine sightline structures of magnetic fields by means of depolarization
and Faraday Tomography. The SKA will be able to drive cosmic magnetism of the
interstellar medium, the Milky Way, galaxies, AGN, galaxy clusters, and
potentially the cosmic web which may preserve information of the primeval
Universe. The Japan SKA Consortium (SKA-JP) Magnetism Science Working Group
(SWG) proposes the project "Resolving 4-D Nature of Magnetism with
Depolarization and Faraday Tomography", which contains ten scientific use
cases.


title: Prescribed Scaler Curvatures for Homogeneous Toric Bundles

abstract:
  In this paper, we study the generalized Abreu equation on a Delzant ploytope
$\Delta \subset \mathbb{R}^2$ and prove the existence of the constant scalar
metrics of homogeneous toric bundles under the assumption of an appropriate
stability.


title: Deep Contrast Learning for Salient Object Detection

abstract:
  Salient object detection has recently witnessed substantial progress due to
powerful features extracted using deep convolutional neural networks (CNNs).
However, existing CNN-based methods operate at the patch level instead of the
pixel level. Resulting saliency maps are typically blurry, especially near the
boundary of salient objects. Furthermore, image patches are treated as
independent samples even when they are overlapping, giving rise to significant
redundancy in computation and storage. In this CVPR 2016 paper, we propose an
end-to-end deep contrast network to overcome the aforementioned limitations.
Our deep network consists of two complementary components, a pixel-level fully
convolutional stream and a segment-wise spatial pooling stream. The first
stream directly produces a saliency map with pixel-level accuracy from an input
image. The second stream extracts segment-wise features very efficiently, and
better models saliency discontinuities along object boundaries. Finally, a
fully connected CRF model can be optionally incorporated to improve spatial
coherence and contour localization in the fused result from these two streams.
Experimental results demonstrate that our deep model significantly improves the
state of the art.


title: On the Implicit Graph Conjecture

abstract:
  The implicit graph conjecture states that every sufficiently small,
hereditary graph class has a labeling scheme with a polynomial-time computable
label decoder. We approach this conjecture by investigating classes of label
decoders defined in terms of complexity classes such as P and EXP. For
instance, GP denotes the class of graph classes that have a labeling scheme
with a polynomial-time computable label decoder. Until now it was not even
known whether GP is a strict subset of GR. We show that this is indeed the case
and reveal a strict hierarchy akin to classical complexity. We also show that
classes such as GP can be characterized in terms of graph parameters. This
could mean that certain algorithmic problems are feasible on every graph class
in GP. Lastly, we define a more restrictive class of label decoders using
first-order logic that already contains many natural graph classes such as
forests and interval graphs. We give an alternative characterization of this
class in terms of directed acyclic graphs. By showing that some small,
hereditary graph class cannot be expressed with such label decoders a weaker
form of the implicit graph conjecture could be disproven.


title: Interior Regularity for a generalized Abreu Equation

abstract:
  We study a generalized Abreu Equation in $n$-dimensional polytopes and derive
interior estimates of solutions under the assumption of the uniform
$K$-stability.


title:
Two Tales of the World: Comparison of Widely Used World News Datasets
  GDELT and EventRegistry

abstract:
  In this work, we compare GDELT and Event Registry, which monitor news
articles worldwide and provide big data to researchers regarding scale, news
sources, and news geography. We found significant differences in scale and news
sources, but surprisingly, we observed high similarity in news geography
between the two datasets.


title: Modeling the dynamics of dissent

abstract:
  We investigate the formation of opinion against authority in an authoritarian
society composed of agents with different levels of authority. We explore a
"dissenting" opinion, held by lower-ranking, obedient, or less authoritative
people, spreading in an environment of an "affirmative" opinion held by
authoritative leaders. A real-world example would be a corrupt society where
people revolt against such leaders, but it can be applied to more general
situations. In our model, agents can change their opinion depending on their
authority relative to their neighbors and their own confidence level. In
addition, with a certain probability, agents can override the affirmative
opinion to take the dissenting opinion of a neighbor. Based on analytic
derivation and numerical simulations, we observe that both the network
structure and heterogeneity in authority, and their correlation, significantly
affect the possibility of the dissenting opinion to spread through the
population. In particular, the dissenting opinion is suppressed when the
authority distribution is very heterogeneous and there exists a positive
correlation between the authority and the number of neighbors of people
(degree). Except for such an extreme case, though, spreading of the dissenting
opinion takes place when people have the tendency to override the authority to
hold the dissenting opinion, but the dissenting opinion can take a long time to
spread to the entire society, depending on the model parameters. We argue that
the internal social structure of agents sets the scale of the time to reach
consensus, based on the analysis of the underlying structural properties of
opinion spreading.

categories: physics.soc-ph cond-mat.stat-mech nlin.AO q-bio.PE


title:
Identifying the production process of new physics at colliders;
  symmetric or asymmetric?

abstract:
  We propose a class of kinematic variables, which is a smooth generalization
of min-max type mass variables such as the Cambridge-$M_{T2}$ and $M_2$, for
measuring a mass spectrum of intermediate resonances in a semi-invisibly
decaying pair production. While kinematic endpoints of min-max type mass
variables are only sensitive to a heavier resonance mass, kinematic endpoints
of new variables are sensitive to all masses. These new mass variables can be
used to resolve a mass spectrum, so that if the true mass spectrum is
asymmetric, then the kinematic endpoints are separate while the endpoints are
the same for the symmetric true mass spectrum. We demonstrate the behavior of
kinematic endpoint of these new variables in pair production of two-body and
three-body decays with one invisible particle.


title: Simulation based estimation of branching models for LTR retrotransposons

abstract:
  Motivation: LTR retrotransposons are mobile elements that are able, like
retroviruses, to copy and move inside eukaryotic genomes. In the present work,
we propose a branching model for studying the propagation of LTR
retrotransposons in these genomes. This model allows to take into account both
positions and degradations of LTR retrotransposons copies. In our model, the
duplication rate is also allowed to vary with the degradation level.
  Results: Various functions have been implemented in order to simulate their
spread and visualization tools are proposed. Based on these simulation tools,
we show that an accurate estimation of the parameters of this propagation model
can be performed. We applied this method to the study of the spread of the
transposable elements ROO, GYPSY, and DM412 on a chromosome of
\textit{Drosophila melanogaster}.
  Availability: Our proposal has been implemented using Python software. Source
code is freely available on the web at
https://github.com/SergeMOULIN/retrotransposons-spread.


title: Graph Theoretic Investigations on Inefficiencies in Network Models

abstract:
  We consider network models where information items flow %are sent from a
source to a sink node. We start with a model where routing is constrained by
energy available on nodes in finite supply (like in Smartdust) and efficiency
is related to energy consumption. We characterize graph topologies ensuring
that every saturating flow under every energy-to-node assignment is maximum and
provide a polynomial-time algorithm for checking this property. We then
consider the standard flow networks with capacity on edges, where again
efficiency is related to maximality of saturating flows, and a traffic model
for selfish routing, where efficiency is related to latency at a Wardrop
equilibrium. Finally, we show that all these forms of inefficiency yield
different classes of graphs (apart from the acyclic case, where the last two
forms generate the same class). Interestingly, in all cases inefficient graphs
can be made efficient by removing edges; this resembles a well-known
phenomenon, called Braess's paradox.


title:
On universal decoherence under gravity: a perspective through the
  Equivalence Principle

abstract:
  In Nature Phys. 11, 668 (2015) (Ref. [1]), a composite particle prepared in a
pure initial quantum state and propagated in a uniform gravitational field is
shown to undergo a decoherence process at a rate determined by the
gravitational acceleration. By assuming Einstein's Equivalence Principle to be
valid, we demonstrate, first in a Lorentz frame with accelerating detectors,
and then directly in the Lab frame with uniform gravity, that the dephasing
between the different internal states arise not from gravity but rather from
differences in their rest mass, and the mass dependence of the de Broglie
wave's dispersion relation. We provide an alternative view to the situation
considered by Ref. [1], where we propose that gravity plays a kinematic role in
the loss of fringe visibility by giving the detector a transverse velocity
relative to the particle beam; visibility can be easily recovered by giving the
screen an appropriate uniform velocity. We finally propose that dephasing due
to gravity may in fact take place for certain modifications to the
gravitational potential where the Equivalence Principle is violated.


title:
Multilevel Models with Stochastic Volatility for Repeated
  Cross-Sections: an Application to tribal Art Prices

abstract:
  In this paper we introduce a multilevel specification with stochastic
volatility for repeated cross-sectional data. Modelling the time dynamics in
repeated cross sections requires a suitable adaptation of the multilevel
framework where the individuals/items are modelled at the first level whereas
the time component appears at the second level. We perform maximum likelihood
estimation by means of a nonlinear state space approach combined with
Gauss-Legendre quadrature methods to approximate the likelihood function. We
apply the model to the first database of tribal art items sold in the most
important auction houses worldwide. The model allows to account properly for
the heteroscedastic and autocorrelated volatility observed and has superior
forecasting performance. Also, it provides valuable information on market
trends and on predictability of prices that can be used by art markets
stakeholders.


title:
Alpert multiwavelets and Legendre-Angelesco multiple orthogonal
  polynomials

abstract:
  We show that the multiwavelets, introduced by Alpert in 1993, are related to
type I Legendre-Angelesco multiple orthogonal polynomials. We give explicit
formulas for these Legendre-Angelesco polynomials and for the Alpert
multiwavelets. The multiresolution analysis can be done entirely using Legendre
polynomials, and we give an algorithm, using Cholesky factorization, to compute
the multiwavelets and a method, using the Jacobi matrix for Legendre
polynomials, to compute the matrices in the scaling relation for any size of
the multiplicity of the multiwavelets.


title:
A matter of words: NLP for quality evaluation of Wikipedia medical
  articles

abstract:
  Automatic quality evaluation of Web information is a task with many fields of
applications and of great relevance, especially in critical domains like the
medical one. We move from the intuition that the quality of content of medical
Web documents is affected by features related with the specific domain. First,
the usage of a specific vocabulary (Domain Informativeness); then, the adoption
of specific codes (like those used in the infoboxes of Wikipedia articles) and
the type of document (e.g., historical and technical ones). In this paper, we
propose to leverage specific domain features to improve the results of the
evaluation of Wikipedia medical articles. In particular, we evaluate the
articles adopting an "actionable" model, whose features are related to the
content of the articles, so that the model can also directly suggest strategies
for improving a given article quality. We rely on Natural Language Processing
(NLP) and dictionaries-based techniques in order to extract the bio-medical
concepts in a text. We prove the effectiveness of our approach by classifying
the medical articles of the Wikipedia Medicine Portal, which have been
previously manually labeled by the Wiki Project team. The results of our
experiments confirm that, by considering domain-oriented features, it is
possible to obtain sensible improvements with respect to existing solutions,
mainly for those articles that other approaches have less correctly classified.
Other than being interesting by their own, the results call for further
research in the area of domain specific features suitable for Web data quality
assessment.


title: Invariant subspaces generated by a single function in the polydisc

abstract:
  In this study, we partially answer the question left open in Rudin's book
"Function theory in polydiscs" on the structure of invariant subspaces of the
Hardy space $H^2(U^n)$ on the polydisc $U^n$. We completely describe all
invariant subspaces generated by a single function in the polydisc. Then, using
our results, we give the unitary equivalence of this type of invariant subspace
and a characterization of outer functions in $H^2(U^n)$.


title: The class of Lucas-Lehmer polynomials

abstract:
  In this paper we introduce a new sequence of polynomials, which follow the
same recursive rule of the well-known Lucas-Lehmer integer sequence. We show
the most important properties of this sequence, relating them to the Chebyshev
polynomials of the first and second kind.


title: Perspective: How good is DFT for water?

abstract:
  Kohn-Sham density functional theory (DFT) has become established as an
indispensable tool for investigating aqueous systems of all kinds, including
those important in chemistry, surface science, biology and the earth sciences.
Nevertheless, many widely used approximations for the exchange-correlation (XC)
functional describe the properties of pure water systems with an accuracy that
is not fully satisfactory. The explicit inclusion of dispersion interactions
generally improves the description, but there remain large disagreements
between the predictions of different dispersion-inclusive methods. We present
here a review of DFT work on water clusters, ice structures and liquid water,
with the aim of elucidating how the strengths and weaknesses of different XC
approximations manifest themselves across this variety of water systems. Our
review highlights the crucial role of dispersion in describing the delicate
balance between compact and extended structures of many different water
systems, including the liquid. By referring to a wide range of published work,
we argue that the correct description of exchange-overlap interactions is also
extremely important, so that the choice of semi-local or hybrid functional
employed in dispersion-inclusive methods is crucial. The origins and
consequences of beyond-2-body errors of approximate XC functionals are noted,
and we also discuss the substantial differences between different
representations of dispersion. We propose a simple numerical scoring system
that rates the performance of different XC functionals in describing water
systems, and we suggest possible future developments.


title:
A Desired PAR-Achieving Precoder Design for Multi-User MIMO OFDM based
  on Concentration of Measure

abstract:
  For multi-user multiple-input and multiple-output (MIMO) wireless
communications in orthogonal frequency di- vision multiplexing systems, we
propose a MIMO precoding scheme providing a desired peak-to-average power ratio
(PAR) at the minimum cost that is defined as received SNR degradation. By
taking advantage of the concentration of measure, we formulate a convex problem
with constraint on the desired PAR. Consequently, the proposed scheme almost
exactly achieves the desired PAR on average, and asymptotically attains the
desired PAR at the 0.001 point of its complementary cumulative distribution
function, as the number of subcarriers increases.


title:
Transfer matrix approach for the Kerr and Faraday rotation in layered
  nanostructures

abstract:
  To study the optical rotation of the polarization of light incident on
multilayer systems consisting of atomically thin conductors and dielectric
multilayers we present a general method based on transfer matrices. The
transfer matrix of the atomically thin conducting layer is obtained using the
Maxwell equations. We derive expressions for the Kerr (Faraday) rotation angle
and for the ellipticity of the reflected (transmitted) light as a function of
the incident angle and polarization of the light. The method is demonstrated by
calculating the Kerr (Faraday) angle for bilayer graphene in the quantum
anomalous Hall state placed on the top of dielectric multilayers. The optical
conductivity of the bilayer graphene is calculated in the framework of a
four-band model.


title:
Substructure and Tidal Streams in the Andromeda Galaxy and its
  Satellites

abstract:
  Tidal streams from existing and destroyed satellite galaxies populate the
outer regions of the Andromeda galaxy (M31). This inhomogeneous debris can be
studied without many of the obstacles that plague Milky Way research. We review
the history of tidal stream research in M31, and in its main satellite
galaxies. We highlight the numerous tidal streams observed around M31, some of
which reside at projected distances of up to 120 kpc from the center of this
galaxy. Most notable is the Giant Stellar Stream, a signature of the most
recent significant accretion event in the M31 system. This event involved an
early-type progenitor of ~10^9 solar masses that came within a few kpc of M31's
center roughly a gigayear ago; almost all of the inner halo debris (within 50
kpc) in M31 can be tied either directly or indirectly to this event. We draw
attention to the fact that most of M31's outer halo globular clusters lie
preferentially on tidal streams and discuss the potential this offers to use
these systems as probes of the accretion history. Tidal features observed
around M33, M32, NGC 205 and NGC 147 are also reviewed. We conclude by
discussing future prospects for this field.


title:
SCOTTI: Efficient Reconstruction of Transmission within Outbreaks with
  the Structured Coalescent

abstract:
  Exploiting pathogen genomes to reconstruct transmission represents a powerful
tool in the fight against infectious disease. However, their interpretation
rests on a number of simplifying assumptions that regularly ignore important
complexities of real data, in particular within-host evolution and non-sampled
patients.
  Here we propose a new approach to transmission inference called SCOTTI
(Structured COalescent Transmission Tree Inference). This method is based on a
statistical framework that models each host as a distinct population, and
transmissions between hosts as migration events. Our computationally efficient
implementation of this model enables the inference of host-to-host transmission
while accommodating within-host evolution and non-sampled hosts. SCOTTI is
distributed as an open source package for the phylogenetic software BEAST2.
  We show that SCOTTI can generally infer transmission events even in the
presence of considerable within-host variation, can account for the uncertainty
associated with the possible presence of non-sampled hosts, and can efficiently
use data from multiple samples of the same host, although there is some
reduction in accuracy when samples are collected very close to the infection
time.
  We illustrate the features of our approach by investigating transmission from
genetic and epidemiological data in a Foot and Mouth Disease Virus (FMDV)
veterinary outbreak in England and a Klebsiella pneumoniae outbreak in a Nepali
neonatal unit. Transmission histories inferred with SCOTTI will be important in
devising effective measures to prevent and halt transmission.


title:
Upper bound on the mass anomalous dimension in many-flavor gauge
  theories: a conformal bootstrap approach

abstract:
  We study four-dimensional conformal field theories with an $SU(N)$ global
symmetry by employing the numerical conformal bootstrap. We consider the
crossing relation associated with a four-point function of a spin~$0$
operator~$\phi_i^{\Bar{k}}$ which belongs to the adjoint representation of
$SU(N)$. For~$N=12$ for example, we found that the theory contains a spin~$0$
$SU(12)$-breaking relevant operator when the scaling dimension
of~$\phi_i^{\Bar{k}}$, $\Delta_{\phi_i^{\Bar{k}}}$, is smaller than~$1.71$.
Considering the lattice simulation of many-flavor quantum chromodynamics with
$12$~flavors on the basis of the staggered fermion, the above $SU(12)$-breaking
relevant operator, if it exists, would be induced by the flavor-breaking effect
of the staggered fermion and prevent an approach to an infrared fixed point.
Actual lattice simulations do not show such signs. Thus, assuming the absence
of the above $SU(12)$-breaking relevant operator, we have an upper bound on the
mass anomalous dimension at the fixed point~$\gamma_m^*\leq1.29$ from the
relation~$\gamma_m^*=3-\Delta_{\phi_i^{\Bar{k}}}$. Our upper bound is not so
strong practically but it is strict within the numerical accuracy. We also find
a kink-like behavior in the boundary curve for the scaling dimension of another
$SU(12)$-breaking operator.


title: Superfluidity and spin superfluidity in spinor Bose gases

abstract:
  We show that spinor Bose gases subject to a quadratic Zeeman effect exhibit
coexisting superfluidity and spin superfluidity, and study the interplay
between these two distinct types of superfluidity. To illustrate that the basic
principles governing these two types of superfluidity are the same, we describe
the magnetization and particle-density dynamics in a single hydrodynamic
framework. In this description spin and mass supercurrents are driven by their
respective chemical potential gradients. As an application, we propose an
experimentally accessible stationary state, where the two types of
supercurrents counterflow and cancel each other, thus resulting in no mass
transport. Furthermore, we propose a straightforward setup to probe spin
superfluidity by measuring the in-plane magnetization angle of the whole cloud
of atoms. We verify the robustness of these findings by evaluating the
four-magnon collision time, and find that the time scale for coherent
(superfluid) dynamics is separated from that of the slower incoherent dynamics
by one order of magnitude. Comparing the atom and magnon kinetics reveals that
while the former can be hydrodynamic, the latter is typically collisionless
under most experimental conditions. This implies that, while our
zero-temperature hydrodynamic equations are a valid description of spin
transport in Bose gases, a hydrodynamic description that treats both mass and
spin transport at finite temperatures may not be readily feasible.


title:
Momentum-space entanglement and Loschmidt echo in Luttinger liquids
  after a quantum quench

abstract:
  Luttinger liquids (LLs) arise by coupling left- and right-moving particles
through interactions in one dimension. This most natural partitioning of LLs is
investigated by the momentum-space entanglement after a quantum quench using
analytical and numerical methods. We show that the momentum-space entanglement
spectrum of a LL possesses many universal features both in equilibrium and
after a quantum quench. The largest entanglement eigenvalue is identical to the
Loschmidt echo, i.e. the overlap of the disentangled and final wavefunctions of
the system. The second largest eigenvalue is the overlap of the first excited
state of the disentangled system with zero total momentum and the final
wavefunction. The entanglement gap is universal both in equilibrium and after a
quantum quench. The momentum-space entanglement entropy is always extensive and
saturates fast to a time independent value after the quench, in sharp contrast
to a spatial bipartitioning.


title: Tuning of thermoelectric properties with changing Se content in Sb2Te3

abstract:
  Polycrystalline Sb 2 Te 3-x Se x (0.0 < x < 1.0) samples were synthesized by
the solid state reaction method. The structural analysis showed that up to the
maximal concentration of Se, the samples possess the Rhombohedral crystal
symmetry (space group R 3 m ). Increase of Se content increases the resistivity
of the samples. Variation of phonon frequencies, observed from Raman
spectroscopic study, depict anomalous behaviour around x = 0.2. The sample Sb 2
Te 2.8 Se 0.2 also shows maximum Seebeck coefficient, carrier concentration and
thermoelectric power factor. Nature of scattering mechanism controlling the
thermopower data has been explored. The thermoelectric properties of the
synthesized materials have been analyzed theoretically in the frame of
Boltzmann equation approach.


title:
Towards Enabling Broadband for a Billon Plus Population with TV White
  Spaces

abstract:
  One of the major impediments to providing broadband connectivity in
semi-urban and rural India is the lack of robust and affordable backhaul. Fiber
connectivity in terms of backhaul that is being planned (or provided) by the
Government of India would reach only till rural offices (named Gram Panchayat)
in the Indian rural areas. In this exposition, we articulate how TV white space
can address the challenge in providing broadband connectivity to a billion plus
population within India. The villages can form local Wi-Fi clusters. The
problem of connecting the Wi-Fi clusters to the optical fiber points can be
addressed using a TV white space based backhaul (middle-mile) network.
  The amount of TV white space present in India is very large when compared
with the developed world. Therefore, we discuss a backhaul architecture for
rural India, which utilizes TV white spaces. We also showcase results from our
TV white space testbed, which support the effectiveness of backhaul by using TV
white spaces. Our testbed provides a broadband access network to rural
population in thirteen villages. The testbed is deployed over an area of
$25$km$^2$, and extends seamless broadband connectivity from optical fiber
locations or Internet gateways to remote (difficult to connect) rural regions.
We also discuss standards and TV white space regulations, which are pertinent
to the backhaul architecture mentioned above.


title: Identifying Randomly Activated Users via Sign-Compute-Resolve on Graphs

abstract:
  In this paper we treat the problem of identification of a subset of active
users in a set of a large number of potentially active users. The users from
the subset are activated randomly, such that the access point (AP) does not
know the subset or its size a priori. The active users are contending to report
their activity to the AP over a multiple access channel. We devise a contention
algorithm that assumes a combination of physical-layer network coding and
K-out-of-N signature coding, allowing for multiple detection of up to K users
at the access point. In addition, we rely on the principles of coded slotted
ALOHA (CSA) and use of successive interference cancellation to enable
subsequent resolution of the collisions that originally featured more than K
users. The objective is to identify the subset of active users such that the
target performance, e.g., probability of active user resolution and/or
throughput is reached, which implies that the duration of the contention period
is also not known a priori. In contrast to standard CSA approaches, in the
proposed algorithm each user, active or not, has a predefined schedule of slots
in which it sends its signature. We analyze the performance of the proposed
algorithm both in the asymptotic and non-asymptotic settings. We also derive an
estimator that, based on the observation of collision multiplicities, estimates
how many users are active and thereby enables tuning of the length of the
contention period.


title: Model discrimination in pseudoscalar-meson photoproduction

abstract:
  To learn about a physical system of interest, experimental results must be
able to discriminate among models. We introduce a geometrical measure to
quantify the distance between models for pseudoscalar-meson photoproduction in
amplitude space. Experimental observables, with finite accuracy, map to
probability distributions in amplitude space, and the characteristic width
scale of such distributions needs to be smaller than the distance between
models if the observable data are going to be useful. We therefore also
introduce a method for evaluating probability distributions in amplitude space
that arise as a result of one or more measurements, and show how one can use
this to determine what further measurements are going to be necessary to be
able to discriminate among models.


title:
Analytical approximations for matter effects on CP violation in the
  accelerator-based neutrino oscillations with E \lesssim 1 GeV

abstract:
  Given an accelerator-based neutrino experiment with the beam energy E
\lesssim 1 GeV, we expand the probabilities of \nu_\mu \to \nu_e and \overline
{\nu}_\mu \to \overline {\nu}_e oscillations in matter in terms of two small
quantities \Delta_{21}/\Delta_{31} and A/\Delta_{31}, where \Delta_{21} \equiv
m^2_2 - m^2_1 and \Delta_{31} \equiv m^2_3 - m^2_1 are the neutrino
mass-squared differences, and A measures the strength of terrestrial matter
effects. Our analytical approximations are numerically more accurate than those
made by Freund in this energy region, and thus they are particularly applicable
for the study of leptonic CP violation in the low-energy MOMENT, ESS\nuSM and
T2K oscillation experiments. As a by-product, the new analytical approximations
help us to easily understand why the matter-corrected Jarlskog parameter
\widetilde{\cal J} peaks at the resonance energy E_* \simeq 0.14 GeV (or 0.12
GeV) for the normal (or inverted) neutrino mass hierarchy, and how the three
Dirac unitarity triangles are deformed due to the terrestrial matter
contamination. We also affirm that a medium-baseline neutrino oscillation
experiment with the beam energy E lying in the E_* \lesssim E \lesssim 2 E_*
range is capable of exploring leptonic CP violation with little matter-induced
suppression.


title:
From A to Z: Supervised Transfer of Style and Content Using Deep Neural
  Network Generators

abstract:
  We propose a new neural network architecture for solving single-image
analogies - the generation of an entire set of stylistically similar images
from just a single input image. Solving this problem requires separating image
style from content. Our network is a modified variational autoencoder (VAE)
that supports supervised training of single-image analogies and in-network
evaluation of outputs with a structured similarity objective that captures
pixel covariances. On the challenging task of generating a 62-letter font from
a single example letter we produce images with 22.4% lower dissimilarity to the
ground truth than state-of-the-art.


title:
Posterior Consistency for Gaussian Process Approximations of Bayesian
  Posterior Distributions

abstract:
  We study the use of Gaussian process emulators to approximate the
parameter-to-observation map or the negative log-likelihood in Bayesian inverse
problems. We prove error bounds on the Hellinger distance between the true
posterior distribution and various approximations based on the Gaussian process
emulator. Our analysis includes approximations based on the mean of the
predictive process, as well as approximations based on the full Gaussian
process emulator. Our results show that the Hellinger distance between the true
posterior and its approximations can be bounded by moments of the error in the
emulator. Numerical results confirm our theoretical findings.


title: Non self-adjoint Hamiltonians with complex eigenvalues

abstract:
  Motivated by what one observes dealing with PT-symmetric quantum mechanics,
we discuss what happens if a physical system is driven by a diagonalizable
Hamiltonian with not all real eigenvalues. In particular, we consider the
functional structure related to systems living in finite-dimensional Hilbert
spaces, and we show that certain intertwining relations can be deduced also in
this case if we introduce suitable antilinear operators. We also analyze a
simple model, computing the transition probabilities in the broken and in the
unbroken regime.


title:
Continuum families of non-displaceable Lagrangian tori in
  $(\mathbb{C}P^1)^{2m}$

abstract:
  We construct a family of Lagrangian tori $\Theta^n_s$ $\subset$
$(\mathbb{C}P^1)^n$, $s \in (0,1)$, where $\Theta^n_{1/2} = \Theta^n$, is the
monotone twist Lagrangian torus described by Chekanov-Schlenk. We show that for
$n = 2m$ and $s \ge 1/2$ these tori are non-displaceable. Then by considering
$\Theta^{k_1}_{s_1}$ $ \times$ $\cdots$ $\times$ $ \Theta^{k_l}_{s_l}$ $
\times$ $ (S^2_{\mathrm{eq}})^{n - \sum_i k_i}$ $ \subset $
$(\mathbb{C}P^1)^n$, with $s_i \in [1/2,1)$ and $k_i \in 2\mathbb{Z}_{>0}$,
$\sum_i k_i \le n$ we get several $l$-dimensional families of non-displaceable
Lagrangian tori. We also show that there exists partial symplectic quasi-states
$\zeta^{\mathfrak{b}_s}_{\textbf{e}_s}$ and linearly independent homogeneous
Calabi quasimorphims $\mu^{\mathfrak{b}_s}_{\textbf{e}_s}$ or which
$\Theta^{2m}_s$ are $\zeta^{\mathfrak{b}_s}_{\textbf{e}_s}$-superheavy and
$\mu^{\mathfrak{b}_s}_{\textbf{e}_s}$-superheavy. We also prove a similar
result for $(\mathbb{C}P^2 3\bar{\mathbb{C}P^2}, \omega_\epsilon)$, where
$\{\omega_\epsilon; 0 < \epsilon < 1\}$ is a family of symplectic forms in
$\mathbb{C}P^2 3\bar{\mathbb{C}P^2}$, for which $\omega_{1/2}$ is monotone.


title:
Fluctuation analysis in nonstationary conditions: single Ca channel
  current in cortical pyramidal neurons

abstract:
  Fluctuation analysis is a method which allows measurement of the single
channel current of ion channels even when it is too small to be resolved
directly with the patch clamp technique. This is the case for voltage-gated
Ca2+ channels (VGCCs). They are present in all mammalian central neurons,
controlling presynaptic release of transmitter, postsynaptic signaling and
synaptic integration. The amplitudes of their single channel currents in a
physiological concentration of extracellular Ca2+, however, are small and not
well determined. But measurement of this quantity is essential for estimating
numbers of functional VGCCs in the membrane and the size of channel-associated
Ca2+ signaling domains, and for understanding the stochastic nature of Ca2+
signaling. Here, we recorded the VGCC current in nucleated patches from layer 5
pyramidal neurons in rat neocortex, in physiological external Ca2+ (1-2 mM).
The ensemble-averaging of current responses required for conventional
fluctuation analysis proved impractical because of the rapid rundown of VGCC
currents. We therefore developed a more robust method, using mean current
fitting of individual current responses and band-pass filtering. Furthermore,
voltage ramp stimulation proved useful. We validated the accuracy of the method
by analyzing simulated data. At an external Ca2+ concentration of 1 mM, and a
membrane potential of -20 mV, we found that the average single channel current
amplitude was about 0.04 pA, increasing to 0.065 pA at 2 mM external Ca2+, and
0.12 pA at 5 mM. The relaxation time constant of the fluctuations was in the
range 0.2-0.8 ms. The results are relevant to understanding the stochastic
properties of dendritic Ca2+ spikes in neocortical layer 5 pyramidal neurons.
With the reported method, single channel current amplitude of native VGCCs can
be resolved accurately despite conditions of unstable rundown.


title: Position paper: Towards an observer-oriented theory of shape comparison

abstract:
  In this position paper we suggest a possible metric approach to shape
comparison that is based on a mathematical formalization of the concept of
observer, seen as a collection of suitable operators acting on a metric space
of functions. These functions represent the set of data that are accessible to
the observer, while the operators describe the way the observer elaborates the
data and enclose the invariance that he/she associates with them. We expose
this model and illustrate some theoretical reasons that justify its possible
use for shape comparison.


title: Fredholm Operators and Spectral Flow

abstract:
  These are extended lecture notes of a PhD course that the author gave at the
Universita degli studi di Torino in Italy in spring 2013.


title: Differentially Private Policy Evaluation

abstract:
  We present the first differentially private algorithms for reinforcement
learning, which apply to the task of evaluating a fixed policy. We establish
two approaches for achieving differential privacy, provide a theoretical
analysis of the privacy and utility of the two algorithms, and show promising
results on simple empirical examples.


title: Independent Sets in Classes Related to Chair/Fork-free Graphs

abstract:
  The Maximum Weight Independent Set (MWIS) problem on graphs with vertex
weights asks for a set of pairwise nonadjacent vertices of maximum total
weight. MWIS is known to be $NP$-complete in general, even under various
restrictions. Let $S_{i,j,k}$ be the graph consisting of three induced paths of
lengths $i, j, k$ with a common initial vertex. The complexity of the MWIS
problem for $S_{1, 2, 2}$-free graphs, and for $S_{1, 1, 3}$-free graphs are
open. In this paper, we show that the MWIS problem can solved in polynomial
time for ($S_{1, 2, 2}$, $S_{1, 1, 3}$, co-chair)-free graphs, by analyzing the
structure of the subclasses of this class of graphs. This extends some known
results in the literature.


title:
Chemical abundances in the multiple sub-giant branch of 47 Tucanae:
  insights on its faint sub-giant branch component

abstract:
  The globular cluster 47 Tuc exhibits a complex sub-giant branch (SGB) with a
faint-SGB comprising only about the 10% of the cluster mass and a bright-SGB
hosting at least two distinct populations.We present a spectroscopic analysis
of 62 SGB stars including 21 faint-SGB stars. We thus provide the first
chemical analysis of the intriguing faint-SGB population and compare its
abundances with those of the dominant populations. We have inferred abundances
of Fe, representative light elements C, N, Na, and Al, {\alpha} elements Mg and
Si for individual stars. Oxygen has been obtained by co-adding spectra of stars
on different sequences. In addition, we have analysed 12 stars along the two
main RGBs of 47 Tuc. Our principal results are: (i) star-to-star variations in
C/N/Na among RGB and bright-SGB stars; (ii) substantial N and Na enhancements
for the minor population corresponding to the faint-SGB; (iii) no high
enrichment in C+N+O for faint-SGB stars. Specifically, the C+N+O of the
faint-SGB is a factor of 1.1 higher than the bright-SGB, which, considering
random (+-1.3) plus systematic errors (+-0.3), means that their C+N+O is
consistent within observational uncertainties. However, a small C+N+O
enrichment for the faint-SGB, similar to what predicted on theoretical ground,
cannot be excluded. The N and Na enrichment of the faint-SGB qualitatively
agrees with this population possibly being He-enhanced, as suggested by theory.
The iron abundance of the bright and faint-SGB is the same to a level of ~0.10
dex, and no other significant difference for the analysed elements has been
detected.


title:
$D$-Wave Charmonia $\eta_{c2}$($1{^1D_2}$), $\psi_2$($1{^3D_2}$), and
  $\psi_3$($1{^3D_3}$) in $B_c$ Decays

abstract:
  We study the semi-leptonic and non-leptonic decays of $B_c$ meson to $D$-wave
charmonia, namely, $\eta_{c2}(1^1\!D_2)$, $\psi_2(1^3\!D_2)$, and
$\psi_3(1^3\!D_3)$. In our calculations, the instantaneous Bethe-Salpeter
method is applied to achieve the hadronic matrix elements. This method includes
relativistic corrections which are important especially for the higher orbital
excited states. For the semi-leptonic decay channels with electron as the final
lepton, we get the branching ratios $\mathcal{B}[B_c \rightarrow
\eta_{c2}e\bar{\nu}_e] = 5.9^{-0.8}_{+1.0}\times 10^{-4}$, $\mathcal{B}[B_c
\rightarrow \psi_2e\bar{\nu}_e]=1.5^{-0.2}_{+0.3}\times 10^{-4}$, and
$\mathcal{B}[B_c \rightarrow \psi_3e\bar{\nu}_e]=3.5^{-0.6}_{+0.8}\times
10^{-4}$. The transition form factors, forward-backward asymmetries, and lepton
spectra in these processes are also presented. For the non-leptonic decay
channels, those with $\rho$ as the lighter meson have the largest branching
ratios, $\mathcal{B}[B_c \rightarrow \eta_{c2}\rho] = 8.1^{-1.0}_{+1.0}\times
10^{-4}$, $\mathcal{B}[B_c \rightarrow \psi_2\rho]=9.6^{-1.0}_{+1.0}\times
10^{-5}$, and $\mathcal{B}[B_c \rightarrow \psi_3\rho]=4.1^{-0.7}_{+0.8}\times
10^{-4}$.


title: Fast Radio Bursts from the Inspiral of Double Neutron Stars

abstract:
  In this paper we propose that a fast radio burst (FRB) could originate from
the magnetic interaction between double neutron stars (NSs) during their final
inspiral within the framework of a unipolar inductor model. In this model, an
electromotive force is induced on one NS to accelerate electrons to an
ultra-relativistic speed instantaneously. We show that coherent curvature
radiation from these electrons moving along magnetic field lines in the
magnetosphere of the other NS is responsible for the observed FRB signal, that
is, the characteristic emission frequency, luminosity, duration and event rate
of FRBs can be well understood. In addition, we discuss several implications of
this model, including double-peaked FRBs and possible associations of FRBs with
short-duration gamma-ray bursts and gravitational wave events.


title:
Statistical mechanics of dense granular fluids - contacts as
  quasi-particles

abstract:
  A new first-principles statistical mechanics formulation is proposed to
describe slow and dilated granular fluids, where prolonged intergranular
contacts vitiate collision theory. The contacts, where all the important
physics takes place, are regarded as quasi-particles that can appear and
disappear. A contact potential, $\nu$, is defined as a measure of the
fluctuations and the mean coordination number per particle and its fluctuations
are calculated as a function of it. This formulation extends the Edwards
statistical mechanics to slow dynamic systems and converges to it when the
motion stops. The theory is applied to a model system of a simply sheared
granular material in the limit of small confining stress. The dependence of the
contact potential on the shear rate is derived, making it possible to calibrate
$\nu$ experimentally and predict the coordination number distribution as a
function of the shear rate. Setting next $\nu=0$ as the jamming point, where
the critical mean coordination number is $z_c$, a finite value is found for the
shear rate there, $\dot{\gamma}_c$. A simple mean field theory then yields the
scaling of the mean coordination number and its fluctuations near
$\dot{\gamma}_c$. Existing results in the literature appear to support the
predictions.


title:
NuSTAR and XMM-Newton observations of 1E1743.1-2843: indications of a
  neutron star LMXB nature of the compact object

abstract:
  We report on the results of NuSTAR and XMM-Newton observations of the
persistent X-ray source 1E1743.1-2843, located in the Galactic Center region.
The source was observed between September and October 2012 by NuSTAR and
XMM-Newton, providing almost simultaneous observations in the hard and soft
X-ray bands. The high X-ray luminosity points to the presence of an accreting
compact object. We analyze the possibilities of this accreting compact object
being either a neutron star (NS) or a black hole, and conclude that the joint
XMM-Newton and NuSTAR spectrum from 0.3 to 40 $\mathrm{keV}$ fits to a black
body spectrum with $kT\sim1.8~\mathrm{keV}$ emitted from a hot spot or an
equatorial strip on a neutron star surface. This spectrum is thermally
Comptonized by electrons with $kT_{e}\sim4.6~\mathrm{keV}$. Accepting this
neutron star hypothesis, we probe the Low Mass (LMXB) or High Mass (HMXB) X-ray
Binary nature of the source. While the lack of Type-I bursts can be explained
in the LMXB scenario, the absence of pulsations in the 2 mHz - 49 Hz frequency
range, the lack of eclipses and of an IR companion, and the lack of a
$K_{\alpha}$ line from neutral or moderately ionized iron strongly disfavor
interpreting this source as a HMXB. We therefore conclude that 1E1743.1-2843 is
most likely a NS-LMXB located beyond the Galactic Center. There is weak
statistical evidence for a soft X-ray excess possibly indicating thermal
emission from an accretion disk. However, the disk normalization remains
unconstrained due to the high hydrogen column density
($N_{H}\sim1.6\times10^{23}~\mathrm{cm^{-2}}$).


title:
High-Contrast Imaging of Intermediate-Mass Giants with Long-Term Radial
  Velocity Trends

abstract:
  A radial velocity (RV) survey for intermediate-mass giants has been operated
for over a decade at Okayama Astrophysical Observatory (OAO). The OAO survey
has revealed that some giants show long-term linear RV accelerations (RV
trends), indicating the presence of outer companions. Direct imaging
observations can help clarify what objects generate these RV trends. We present
the results of high-contrast imaging observations or six intermediate-mass
giants with long-term RV trends using the Subaru Telescope and HiCIAO camera.
We detected co-moving companions to $\gamma$ Hya B ($0.61^{+0.12}_{-0.14}
M_\odot$), HD 5608 B ($0.10 \pm 0.01 M_\odot$), and HD 109272 B ($0.28 \pm 0.06
M_\odot$). For the remaining targets($\iota$ Dra, 18 Del, and HD 14067) we
exclude companions more massive than 30-60 $M_\mathrm{Jup}$ at projected
separations of 1arcsec-7arcsec. We examine whether these directly imaged
companions or unidentified long-period companions can account for the RV trends
observed around the six giants. We find that the Kozai mechanism can explain
the high eccentricity of the inner planets $\iota$ Dra b, HD 5608 b, and HD
14067 b.


title: Linear Codes over Galois Ring $GR(p^2,r)$ Related to Gauss sums

abstract:
  Linear codes over finite rings become one of hot topics in coding theory
after Hommons et al.([4], 1994) discovered that several remarkable nonlinear
binary codes with some linear-like properties are the images of Gray map of
linear codes over $Z_4$. In this paper we consider two series of linear codes
$C(G)$ and $\widetilde{C}(G)$ over Galois ring $R=GR(p^2,r)$, where $G$ is a
subgroup of $R^{(s)^*}$ and $R^{(s)}=GR(p^2,rs)$. We present a general formula
on $N_\beta(a)$ in terms of Gauss sums on $R^{(s)}$ for each $a\in R$, where
$N_\beta(a)$ is the number of a-component of the codeword $c_\beta\in C(G)
(\beta\in R^{(s)})$ (Theorem 3.1). We have determined the complete Hamming
weight distribution of $C(G)$ and the minimum Hamming distance of
$\widetilde{C}(G)$ for some special G (Theorem 3.3 and 3.4). We show a general
formula on homogeneous weight of codewords in $C(G)$ and $\widetilde{C}(G)$
(Theorem 4.5) for the special $G$ given in Theorem 3.4. Finally we obtained
series of nonlinear codes over $\mathbb{F}_{q} \ (q=p^r)$ with two Hamming
distance by using Gray map (Corollary 4.6).


title: Individual Microscopic Results Of Bottleneck Experiments

abstract:
  This contribution provides microscopic experimental study of pedestrian
motion in front of the bottleneck, explains the high variance of individual
travel time by the statistical analysis of trajectories. The analysis shows
that this heterogeneity increases with increasing occupancy. Some participants
were able to reach lower travel time due more efficient path selection and more
aggressive behavior within the crowd. Based on this observations, linear model
predicting travel time with respect to the aggressiveness of pedestrian is
proposed.


title: Prony's method on the sphere

abstract:
  Eigenvalue analysis based methods are well suited for the reconstruction of
finitely supported measures from their moments up to a certain degree. We give
a precise description when Prony's method succeeds in terms of an interpolation
condition. In particular, this allows for the unique reconstruction of a
measure from its trigonometric moments whenever its support is separated and
also for the reconstruction of a measure on the unit sphere from its moments
with respect to spherical harmonics. Both results hold in arbitrary dimensions
and also yield a certificate for popular semidefinite relaxations of these
reconstruction problems.


title: Machine Learning for Protein Function

abstract:
  Systematic identification of protein function is a key problem in current
biology. Most traditional methods fail to identify functionally equivalent
proteins if they lack similar sequences, structural data or extensive manual
annotations. In this thesis, I focused on feature engineering and machine
learning methods for identifying diverse classes of proteins that share
functional relatedness but little sequence or structural similarity, notably,
Neuropeptide Precursors (NPPs).
  I aim to identify functional protein classes solely using unannotated protein
primary sequences from any organism. This thesis focuses on feature
representations of whole protein sequences, sequence derived engineered
features, their extraction, frameworks for their usage by machine learning (ML)
models, and the application of ML models to biological tasks, focusing on high
level protein functions. I implemented the ideas of feature engineering to
develop a platform (called NeuroPID) that extracts meaningful features for
classification of overlooked NPPs. The platform allows mass discovery of new
NPs and NPPs. It was expanded as a webserver.
  I expanded our approach towards other challenging protein classes. This is
implemented as a novel bioinformatics toolkit called ProFET (Protein Feature
Engineering Toolkit). ProFET extracts hundreds of biophysical and sequence
derived attributes, allowing the application of machine learning methods to
proteins. ProFET was applied on many protein benchmark datasets with state of
the art performance. The success of ProFET applies to a wide range of
high-level functions such as metagenomic analysis, subcellular localization,
structure and unique functional properties (e.g. thermophiles, nucleic acid
binding).
  These methods and frameworks represent a valuable resource for using ML and
data science methods on proteins.


title: Pressure tuning the lattice and optical response of silver sulfide

abstract:
  Binary transition metal chalcogenides have attracted increasing attention for
their unique structural and electronic properties. High pressure is powerful
tool for tuning their crystal structure and electronic structure away from
their pristine states.In this work, we systematically studied the in situ
structural and optical behavior of silver sulfide (Ag2S) under pressure by
X-ray diffraction (XRD) and Infrared (IR) spectroscopy measurements in a
diamond anvil cell. Upon compression, Ag2S undergoes structural symmetrization
from monoclinic to orthorhombic, represented by the decrease of angle from 99
to 90 degrees through a series of structural transitions coupled with lattice
contractions. IR transmission and reflectivity measurements showed that
pressure effectively tunes semiconducting Ag2S into a metal at ~ 22 GPa. Drude
model analysis of the IR reflectivity indicates that the optical conductivity
evolves significantly, reaching the highest conductivity at ~ 40 GPa. Our
results highlight pressure's dramatic role in tuning the structural and
electronic state of silver chacogenides.


title:
Supervisor Localization of Timed Discrete-Event Systems under Partial
  Observation and Communication Delay

abstract:
  We study supervisor localization for timed discrete-event systems under
partial observation and communication delay in the Brandin-Wonham framework.
First, we employ timed relative observability to synthesize a
partial-observation monolithic supervisor; the control actions of this
supervisor include not only disabling action of prohibitible events (as that of
controllable events in the untimed case) but also "clock-preempting" action of
forcible events. Accordingly we decompose the supervisor into a set of
partial-observation local controllers one for each prohibitible event, as well
as a set of partial-observation local preemptors one for each forcible event.
We prove that these local controllers and preemptors collectively achieve the
same controlled behavior as the partial-observation monolithic supervisor does.
Moreover, we propose channel models for inter-agent event communication and
impose bounded and unbounded delay as temporal specifications. In this
formulation, there exist multiple distinct observable event sets; thus we
employ timed relative coobservability to synthesize partial-observation
decentralized supervisors, and then localize these supervisors into local
controllers and preemptors. The above results are illustrated by a timed
workcell example.


title: A co-analytic Cohen indestructible maximal cofinitary group

abstract:
  Assuming that every set is constructible, we find a $\Pi^1_1$ maximal
cofinitary group of permutations of $\mathbb N$ which is indestructible by
Cohen forcing. Thus we show that the existence of such groups is consistent
with arbitrarily large continuum. Our method also gives a new proof, inspired
by the forcing method, of Kastermans' result that there exists a $\Pi^1_1$
maximal cofinitary group in $L$.


title: Construction of 3-Designs Using (1,\sigma)-Resolution

abstract:
  The paper deals with recursive constructions for simple 3-designs based on
other 3-designs having $(1, \sigma)$-resolution. The concept of $(1,
\sigma)$-resolution may be viewed as a generalization of the parallelism for
designs. We show the constructions and their applications to produce many
previously unknown infinite families of simple 3-designs.
  We also include a discussion of $(1,\sigma)$-resolvability of the constructed
designs.


title:
Comparing a mercury optical lattice clock with microwave and optical
  frequency standards

abstract:
  In this paper we report the evaluation of an optical lattice clock based on
neutral mercury down to a relative uncertainty of $1.7\times 10^{-16}$.
Comparing this characterized frequency standard to a Cs atomic fountain we
determine the absolute frequency of the $^1S_0 \rightarrow \phantom{}^3P_0$
transition of $^{199}$Hg as $\nu_{\mathrm{Hg}} = 1
128\,575\,290\,808\,154.62\,$Hz $\pm\,0.19\,$Hz (statistical) $\pm\,0.38\,$Hz
(systematic), limited solely by the realization of the SI second. Furthermore,
by comparing the mercury optical lattice clock to a Rb atomic fountain, we
determine for the first time to our knowledge the ratio between the $^{199}$Hg
clock transition and the $^{87}$Rb ground state hyperfine transition. Finally
we present a direct optical to optical measurement of the $^{199}$Hg/$^{87}$Sr
frequency ratio. The obtained value of
$\nu_{\mathrm{Hg}}/\nu_{\mathrm{Sr}}=2.629\,314\,209\,898\,909\,15$ with a
fractional uncertainty of $1.8\times10^{-16}$ is in excellent agreement with
the same measurement obtained by Yamanaka et al. (arXiv:1503.07941). This makes
this frequency ratio one of the few physical quantities agreed upon by
different laboratories to this level of uncertainty. Frequency ratio
measurements of the kind of those reported in this paper have a strong impact
for frequency metrology but also for fundamental physics as they can be used to
monitor putative variations of fundamental constants.


title: Surface abundances of OC supergiants

abstract:
  Some O and B stars show unusually strong or weak lines of carbon and/or
nitrogen. These objects are classified as OBN or OBC stars. It has recently
been shown that nitrogen enrichment and carbon depletion are the most likely
explanations for the existence of the ON class. We investigate OC stars (all
being supergiants) to check that surface abundances are responsible for the
observed anomalous line strengths. We perform a spectroscopic analysis of three
OC supergiants using atmosphere models. A fourth star was previously studied by
us. Our sample thus comprises all OC stars known to date in the Galaxy. We
determine the stellar parameters and He, C, N, and O surface abundances. We
show that all stars have effective temperatures and surface gravities fully
consistent with morphologically normal O supergiants. However, OC stars show
little, if any, nitrogen enrichment and carbon surface abundances consistent
with the initial composition. OC supergiants are thus barely chemically
evolved, unlike morphologically normal O supergiants.


title:
Adaptive Visualisation System for Construction Building Information
  Models Using Saliency

abstract:
  Building Information Modeling (BIM) is a recent construction process based on
a 3D model, containing every component related to the building achievement.
Architects, structure engineers, method engineers, and others participant to
the building process work on this model through the design-to-construction
cycle. The high complexity and the large amount of information included in
these models raise several issues, delaying its wide adoption in the industrial
world. One of the most important is the visualization: professionals have
difficulties to find out the relevant information for their job. Actual
solutions suffer from two limitations: the BIM models information are processed
manually and insignificant information are simply hidden, leading to
inconsistencies in the building model. This paper describes a system relying on
an ontological representation of the building information to label
automatically the building elements. Depending on the user's department, the
visualization is modified according to these labels by automatically adjusting
the colors and image properties based on a saliency model. The proposed
saliency model incorporates several adaptations to fit the specificities of
architectural images.


title: Encoding M classical bits in the arrival time of dense-coded photons

abstract:
  We present a scheme to encode M extra classical bits to a dense-coded pair of
photons. By tuning the delay of an entangled pair of photons to one of 2^M
time-bins and then applying one of the quantum dense coding protocols, a
receiver equipped with a synchronized clock of reference is able to decode M
bits (via classical time-bin encoding) + 2 bits (via quantum dense coding).
This protocol, yet simple, does not dispense several special features of the
used programmable delay apparatus to maintain the coherence of the two-photon
state. While this type of time-domain encoding may be thought to be ideally of
boundless photonic capacity (by increasing the number of available time-bins),
errors due to the environmental noise and the imperfect devices and channel
evolve with the number of time-bins.


title: Density and structural anomalies in soft-repulsive dimeric fluids

abstract:
  We report Monte Carlo results for the fluid structure of a system of dimeric
particles interacting via a core-softened potential. More specifically, dimers
interact through a repulsive pair potential of inverse-power form, modified in
such a way that the repulsion strength is softened in a given range of
distances. The aim of such a study is to investigate how both the elongation of
the dimers and the softness of the potential affect some features of the model.
Our results show that the dimeric fluid exhibits both density and structural
anomalies even if the interaction is not characterized by two length scales.
Upon increasing the aspect ratio of the dimers, such anomalies are
progressively hindered, with the structural anomaly surviving even after the
disappearance of the density anomaly. These results shed light on the peculiar
behaviour of molecular systems of non-spherical shape, showing how geometrical
and interaction parameters play a fundamental role for the presence of
anomalies.


title: How to make RSA and some other encryptions probabilistic

abstract:
  A new scheme of probabilistic subgroup-related encryption is introduced. Some
applications of this scheme based on the RSA, Diffie-Hellman and ElGamal
encryption algorithms are described. Security assumptions and main advantages
of this scheme are discussed. We outline that this scheme is potentially
semantically secure under reasonable cryptographic assumptions.


title: There is no (95,40,12,20) strongly regular graph

abstract:
  We show that there is no $(95,40,12,20)$ strongly regular graph and,
consequently, there is no $(96,45,24,18)$ strongly regular graph, no two-graph
on $96$ vertices, and no partial geometry $\rm{pg}(5,9,3)$. The main idea of
the result is based on the star complement technique and requires a small
amount of computation.


title:
Colour-Kinematics duality and the Drinfeld double of the Lie algebra of
  diffeomorphisms

abstract:
  Colour-kinematics duality suggests that Yang-Mills (YM) theory possesses some
hidden Lie algebraic structure. So far this structure has resisted
understanding, apart from some progress in the self-dual sector. We show that
there is indeed a Lie algebra behind the YM Feynman rules. The Lie algebra we
uncover is the Drinfeld double of the Lie algebra of vector fields. More
specifically, we show that the kinematic numerators following from the YM
Feynman rules satisfy a version of the Jacobi identity, in that the Jacobiator
of the bracket defined by the YM cubic vertex is cancelled by the contribution
of the YM quartic vertex. We then show that this Jacobi-like identity is in
fact the Jacobi identity of the Drinfeld double. All our considerations are
off-shell. Our construction explains why numerators computed using the Feynman
rules satisfy the colour-kinematics at four but not at higher numbers of
points. It also suggests a way of modifying the Feynman rules so that the
duality can continue to hold for an arbitrary number of gluons. Our
construction stops short of producing explicit higher point numerators because
of an absence of a certain property at four points. We comment on possible ways
of correcting this, but leave the next word in the story to future work.


title:
Comments on "Overdemodulation for High-Performance Receivers with
  Low-Resolution ADC"

abstract:
  This submission has been withdrawn by arXiv administrators due to
misrepresentation of authorship.


title:
Zero-energy modes and valley asymmetry in the Hofstadter spectrum of
  bilayer graphene van der Waals heterostructures with hBN

abstract:
  We investigate the magnetic minibands of a heterostructure consisting of
bilayer graphene (BLG) and hexagonal boron nitride (hBN) by numerically
diagonalizing a two-band Hamiltonian that describes electrons in BLG in the
presence of a moire potential. Due to inversion-symmetry breaking
characteristic for the moire potential, the valley symmetry of the spectrum is
broken, but despite this, the zero-energy Landau level in BLG survives, albeit
with reduced degeneracy. In addition, we derive effective models for the
low-energy features in the magnetic minibands and demonstrate the appearance of
secondary Dirac points in the valence band, which we confirm by numerical
simulations. Then, we analyze how single-particle gaps in the fractal energy
spectrum produce a sequence of incompressible states observable under a
variation of carrier density and magnetic field.


title: The Langevin Approach: An R Package for Modeling Markov Processes

abstract:
  We describe an R package developed by the research group Turbulence, Wind
energy and Stochastics (TWiSt) at the Carl von Ossietzky University of
Oldenburg, which extracts the (stochastic) evolution equation underlying a set
of data or measurements. The method can be directly applied to data sets with
one or two stochastic variables. Examples for the one-dimensional and
two-dimensional cases are provided. This framework is valid under a small set
of conditions which are explicitly presented and which imply simple preliminary
test procedures to the data. For Markovian processes involving Gaussian white
noise, a stochastic differential equation is derived straightforwardly from the
time series and captures the full dynamical properties of the underlying
process. Still, even in the case such conditions are not fulfilled, there are
alternative versions of this method which we discuss briefly and provide the
user with the necessary bibliography.


title: Little Higgs after the little one

abstract:
  At the LHC, the Littlest Higgs Model with $T$-parity is characterised by
various production channels. If the $T$-odd quarks are heavier than the exotic
partners of the $W$ and the $Z$, then associated production can be as important
as the pair-production of the former. Studying both, we look for final states
comprising at least one lepton, jets and missing transverse energy. We consider
all the SM processes that could conspire to contribute as background to our
signals, and perform a full detector level simulation of the signal and
background to estimate the discovery potential at the current run as well as at
the scheduled upgrade of the LHC. We also show that, for one of the channels,
the reconstruction of two tagged $b$-jets at the Higgs mass $(M_h = 125~{\rm
GeV})$ provides us with an unambiguous hint for this model.


title: Unscented Bayesian Optimization for Safe Robot Grasping

abstract:
  We address the robot grasp optimization problem of unknown objects
considering uncertainty in the input space. Grasping unknown objects can be
achieved by using a trial and error exploration strategy. Bayesian optimization
is a sample efficient optimization algorithm that is especially suitable for
this setups as it actively reduces the number of trials for learning about the
function to optimize. In fact, this active object exploration is the same
strategy that infants do to learn optimal grasps. One problem that arises while
learning grasping policies is that some configurations of grasp parameters may
be very sensitive to error in the relative pose between the object and robot
end-effector. We call these configurations unsafe because small errors during
grasp execution may turn good grasps into bad grasps. Therefore, to reduce the
risk of grasp failure, grasps should be planned in safe areas. We propose a new
algorithm, Unscented Bayesian optimization that is able to perform sample
efficient optimization while taking into consideration input noise to find safe
optima. The contribution of Unscented Bayesian optimization is twofold as if
provides a new decision process that drives exploration to safe regions and a
new selection procedure that chooses the optimal in terms of its safety without
extra analysis or computational cost. Both contributions are rooted on the
strong theory behind the unscented transformation, a popular nonlinear
approximation method. We show its advantages with respect to the classical
Bayesian optimization both in synthetic problems and in realistic robot grasp
simulations. The results highlights that our method achieves optimal and robust
grasping policies after few trials while the selected grasps remain in safe
regions.


title:
Observation of a 4-spin Plaquette Singlet State in the
  Shastry-Sutherland compound SrCu2(BO3)2

abstract:
  The study of interacting spin systems is of fundamental importance for modern
condensed matter physics. On frustrated lattices, magnetic exchange
interactions cannot be simultaneously satisfied, and often give rise to
competing exotic ground states. The frustrated 2D Shastry-Sutherland lattice
realized by SrCu2(BO3)2 is an important test to our understanding of quantum
magnetism. It was constructed to have an exactly solvable 2-spin dimer singlet
ground state within a certain range of exchange parameters and frustration.
While the exact dimer state and the antiferromagnetic order at both ends of the
phase diagram are well known, the ground state and spin correlations in the
intermediate frustration range have been widely debated. We report here the
first experimental identification of the conjectured plaquette singlet
intermediate phase in SrCu2(BO3)2. It is observed by inelastic neutron
scattering after pressure tuning at 21.5 kbar. This gapped plaquette singlet
state with strong 4-spin correlations leads to a transition to an ordered Neel
state above 40 kbar, which can realize a deconfined quantum critical point.


title:
Dynamical Lamb effect versus dissipation in superconducting quantum
  circuits

abstract:
  Superconducting circuits provide a new platform to study nonstationary cavity
QED phenomena. An example of such a phenomenon is a dynamical Lamb effect which
is a parametric excitation of an atom due to the nonadiabatic modulation of its
Lamb shift. This effect has been initially introduced for a natural atom in a
varying cavity, while we suggested its realization in a superconducting
qubit-cavity system with dynamically tunable coupling. In the present paper, we
study the interplay between the dynamical Lamb effect and the energy
dissipation, which is unavoidable in realistic systems. We find that despite of
naive expectations this interplay can lead to unexpected dynamical regimes. One
of the most striking results is that photon generation from vacuum can be
strongly enhanced due to the qubit relaxation, which opens a new channel for
such a process. We also show that dissipation in the cavity can increase the
qubit excited state population. Our results can be used for the experimental
observation and investigation of the dynamical Lamb effect and accompanying
quantum effects.


title: Learning Shared Representations in Multi-task Reinforcement Learning

abstract:
  We investigate a paradigm in multi-task reinforcement learning (MT-RL) in
which an agent is placed in an environment and needs to learn to perform a
series of tasks, within this space. Since the environment does not change,
there is potentially a lot of common ground amongst tasks and learning to solve
them individually seems extremely wasteful. In this paper, we explicitly model
and learn this shared structure as it arises in the state-action value space.
We will show how one can jointly learn optimal value-functions by modifying the
popular Value-Iteration and Policy-Iteration procedures to accommodate this
shared representation assumption and leverage the power of multi-task
supervised learning. Finally, we demonstrate that the proposed model and
training procedures, are able to infer good value functions, even under low
samples regimes. In addition to data efficiency, we will show in our analysis,
that learning abstractions of the state space jointly across tasks leads to
more robust, transferable representations with the potential for better
generalization. this shared representation assumption and leverage the power of
multi-task supervised learning. Finally, we demonstrate that the proposed model
and training procedures, are able to infer good value functions, even under low
samples regimes. In addition to data efficiency, we will show in our analysis,
that learning abstractions of the state space jointly across tasks leads to
more robust, transferable representations with the potential for better
generalization.


title: Radio Astrometry towards the Nearby Universe with the SKA

abstract:
  This chapter summarizes radio astrometry in relation to current very long
baseline interferometry (VLBI) projects and describes its perspectives with the
SKA. The scientific goals of the astrometry with the SKA have been discussed in
the international and Japanese communities of researchers, whose major issues
are shown here. We have demonstrated some of the issues, such as censuses of
possible targets and the technical feasibility of astrometry in the SKA
frequency bands. The preliminary results of our case studies on SKA astrometry
are also presented. In addition, possible synergy and commensality of the SKA
astrometric projects with those in the optical and infrared astrometric
missions, especially JASMINE (Japan Astrometry Satellite Mission for INfrared
Exploration) are discussed.


title:
Site-specific $^{13}$C NMR study on locally distorted triangular lattice
  of organic conductor $\kappa$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$

abstract:
  To verify the effect of geometrical frustration, we artificially distort the
triangular lattice of quasi-two-dimensional organic conductor
$\kappa$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$ [BEDT-TTF:
bis(ethylenedithio)terathiofulvalene] by analogous-molecular substitution and
apply $^{13}$C NMR of bulk and substituted sites, electric conductivity, and
static magnetic susceptibility measurements. The results indicate that the
magnetic characteristics of the substituted sample are quantitatively similar
to those of the pure sample. Moreover the magnetic characteristics at the
substituted sites are also the same as in the bulk. These results suggest that
the observed magnetic properties may not be due to the geometrical frustration
but the importance of disorder.


title: Distributed Model Predictive Control Using a Chain of Tubes

abstract:
  A new distributed MPC algorithm for the regulation of dynamically coupled
subsystems is presented in this paper. The current control action is computed
via two robust controllers working in a nested fashion. The inner controller
builds a nominal reference trajectory from a decentralized perspective. The
outer controller uses this information to take into account the effects of the
coupling and generate a distributed control action. The tube-based approach to
robustness is employed. A supplementary constraint is included in the outer
optimization problem to provide recursive feasibility of the overall controller


title:
Accurate relative-phase and time-delay maps all over the emission cone
  of hyperentangled photon source

abstract:
  High flux of hyperentangled photons entails collecting the two-photon
emission over relatively wide extent in frequency and transverse space within
which the photon pairs are simultaneously entangled in multiple degrees of
freedom. In this paper, we present a numerical approach to determining the
spatial-spectral relative-phase and time-delay maps of hyperentangled photons
all over the spontaneous parametric down conversion (SPDC) emission cone. We
consider the hyperentangled-photons produced by superimposing noncollinear SPDC
emissions of two crossed and coherently-pumped nonlinear crystals. We adopt a
vectorial representation for all parameters of concern. This enables us to
study special settings such as the self-compensation via oblique pump
incidence. While rigorous quantum treatment of SPDC emission requires Gaussian
state representation, in low-gain regime (like the case of the study), it is
well approximated to the first order to superposition of vacuum and two-photon
states. The relative phase and time-delay maps are then calculated between the
two-photon wavepackets created along symmetrical locations of the crystals.
Assuming monochromatic plane-wave pump field, the mutual signal-idler relations
like energy conservation and transverse-momentum conservation define well one
of the two-photon with reference to its conjugate. The weaker conservation of
longitudinal momentum (due to relatively thin crystals) allows two-photon
emission directions coplanar with the pump beam while spreading around the
perfect phase-matching direction. While prior works often adopt first-order
approximation, it is shown that the relative-phase map is a very well
approximated to a quadratic function in the polar angle of the two-photon
emission while negligibly varying with the azimuthal angle.


title: Quantum Renewal Equation for the first detection time of a quantum walk

abstract:
  We investigate the statistics of the first detected passage time of a quantum
walk. The postulates of quantum theory, in particular the collapse of the wave
function upon measurement, reveal an intimate connection between the wave
function of a process free of measurements, i.e. the solution of the
Schr\"odinger equation, and the statistics of first detection events on a site.
For stroboscopic measurements a quantum renewal equation yields basic
properties of quantum walks. For example, for a tight binding model on a ring
we discover critical sampling times, diverging quantities such as the mean time
for first detection, and an optimal detection rate. For a quantum walk on an
infinite line the probability of first detection decays like
$(\mbox{time})^{-3}$ with a superimposed oscillation, critical behavior for a
specific choice of sampling time, and vanishing amplitude when the sampling
time approaches zero due to the quantum Zeno effect.


title:
Ordering and order-disorder phase transition in the (1x1) monolayer
  chemisorbed on the (111) face of an fcc crystal

abstract:
  In this paper we have considered a simple lattice gas model of chemisorbed
monolayer which allows for the harmonic fluctuations of the bond length between
the adsorbate atom and the surface site. The model also involves a short-ranged
attractive potential acting between the adsorbed atoms as well as the surface
periodic corrugation potential. It has been assumed that the adsorbed atoms are
bonded to the uppermost layer of the substrate atoms. In particular, using
Monte Carlo simulation method we have focused on the orderings appearing in the
dense monolayer formed on the (111) face of an fcc solid. Within the lattice
gas limit, the chemisorbed layer forms a (1x1) structure. On the other hand,
when the bonds are allowed to fluctuate, three other different ordered phases
have been found to be stable in the ground state. One of them has been found to
be stable at finite temperatures and to undergo a phase transition to the
disordered state. The remaining two ordered states have been found to be stable
in the ground state only. At finite temperatures, the ordering has been
demonstrated to be destroyed due to large entropic effects.


title:
Properties of a one-dimensional periodicity of the gravitational
  interaction

abstract:
  We briefly discuss the possibility to describe with a formalism, analogous to
the Bragg law and the transfer matrix method used for photonic crystals, the
behaviour of the kinetic energy of an object travelling through a
one-dimensional (1D) modulation of the gravitational interaction, i.e. a 1D
gravitational crystal. We speculate that certain ranges of the kinetic energy
of an object with mass m and speed v cannot travel through the crystal, giving
rise to a gravitational gap.


title:
Prediction of functional ARMA processes with an application to traffic
  data

abstract:
  This work is devoted to functional ARMA$(p, q)$ processes and approximating
vector models based on functional PCA in the context of prediction. After
deriving sufficient conditions for the existence of a stationary solution to
both the functional and the vector model equations, the structure of the
approximating vector model is investigated. The stationary vector process is
used to predict the functional process. A bound for the difference between
vector and functional best linear predictor is derived. The paper concludes by
applying functional ARMA processes for the modeling and prediction of highway
traffic data.


title:
Unexpected series of regular frequency spacing of delta Scuti stars in
  the non-asymptotic regime -- I. The methodology

abstract:
  A sequence search method was developed to search regular frequency spacing in
delta Scuti stars by visual inspection and algorithmic search. We searched for
sequences of quasi-equally spaced frequencies, containing at least four members
per sequence, in 90 delta Scuti stars observed by CoRoT. We found an
unexpectedly large number of independent series of regular frequency spacing in
77 delta Scuti stars (from 1 to 8 sequences) in the non-asymptotic regime. We
introduce the sequence search method presenting the sequences and echelle
diagram of CoRoT 102675756 and the structure of the algorithmic search. Four
sequences (echelle ridges) were found in the 5-21 d^{-1} region, where the
pairs of the sequences are shifted (between 0.5-0.59 d^{-1}) by twice the value
of the estimated rotational splitting frequency (0.269 d^{-1}). The general
conclusions for the whole sample are also presented in this paper. The
statistics of the spacings derived by the sequence search method, by FT and
that of the shifts are also compared. In many stars, more than one almost
equally valid spacing appeared. The model frequencies of FG Vir and their
rotationally split components were used to reveal a possible explanation that
one spacing is the large separation, while the other is a sum of the large
separation and the rotational frequency. In CoRoT 102675756, the two spacings
(2.249 and 1.977 d^{-1}) agree better with the sum of a possible 1.710 d^{-1}
large separation and two or one times, respectively, the value of the
rotational frequency.


title:
Heavy baryonic resonances, multistrange hadrons, and equilibration at
  energies available at the GSI Schwerionensynchrotron, SIS18

abstract:
  We study the details and time dependence of particle production in nuclear
collisions at a fixed target beam energy of $E_{\mathrm{lab}}= 1.76$ A GeV with
the UrQMD transport model. We find that the previously proposed production
mechanism for multi strange hadrons, $\phi$ and $\Xi$, are possible due to
secondary interactions of incoming nuclei of the projectile and target with
already created nuclear resonances, while the Fermi momenta of the nuclei play
only a minor role. We also show how the centrality dependence of these particle
multiplicities can be used to confirm the proposed mechanism, as it strongly
depends on the number of participants in the reaction. Furthermore we
investigate the time dependence of particle production in collisions of Ca+Ca
at this beam energy, in order to understand the origins of the apparent
chemical equilibration of the measured particle yields. We find that indeed the
light hadron yields appear to be in equilibrium already from the very early
stage of the collision while in fact no local equilibration, through multi
collision processes, takes place. The apparent equilibrium is reached only
through the decay of the resonances according to available phase space.


title:
Constraining the Schwarzschild-de Sitter Solution in Models of Modified
  Gravity

abstract:
  The Schwarzschild-de Sitter (SdS) solution exists in the large majority of
modified gravity theories, as expected, and in particular the effective
cosmological constant is determined by the specific parameters of the given
theory. We explore the possibility to use future extended radio-tracking data
from the currently ongoing New Horizons mission in the outskirts peripheries of
the Solar System, at about 40 au, in order to constrain this effective
cosmological constant, and thus to impose constrain on each scenario's
parameters. We investigate some of the recently most studied modified
gravities, namely $f(R)$ and $f(T)$ theories, dRGT massive gravity, and
Ho\v{r}ava-Lifshitz gravity, and we show that New Horizons mission may bring an
improvement of one-two orders of magnitude with respect to the present bounds
from planetary orbital dynamics.

categories: gr-qc astro-ph.EP hep-ph physics.space-ph


title: The Heun operator as a Hamiltonian

abstract:
  IIt is shown that the celebrated Heun operator $H_e=-(a_0 x^3 + a_1 x^2 + a_2
x) \frac{d^2}{dx^2} + (b_0 x^2 + b_1 x + b_2)\frac{d}{dx} + c_0 x$ is the
Hamiltonian of the $sl(2,R)$-quantum Euler-Arnold top of spin $\nu$ in a
constant magnetic field. For $a_0 \neq 0$ it is canonically-equivalent to
$BC_1(A_1)-$ Calogero-Moser-Sutherland quantum models, if $a_0=0$, ten known
one-dimensional quasi-exactly-solvable problems are reproduced, and if, in
addition, $b_0=c_0=0$, then four well-known one-dimensional quantal
exactly-solvable problems are reproduced. If spin $\nu$ of the top takes
(half)-integer value the Hamiltonian possesses a finite-dimensional invariant
subspace and a number of polynomial eigenfunctions occurs. Discrete systems on
uniform and exponential lattices are introduced which are
canonically-equivalent to one described by the Heun operator.


title: Transport properties of spin-triplet superconducting monolayer $MoS_2$

abstract:
  The quantum transport properties of graphene and monolayer $MoS_2$
superconductor heterostructures has been of considerable importance in the
recent few years. Layered nature of molybdenum disulfide permits the
superconducting correlation induction. Moreover, peculiar dynamical features of
monolayer $MoS_2$, such as valence band spin-splitting in the nondegenerate $K$
and $K'$ valleys originated from strong spin-orbit coupling, and considerable
direct band gap can make it potentially a useful material for electronics
applications. Using the Dirac-like Hamiltonian of $MoS_2$ with taking into
account the related mass asymmetry and topological contributions, we
investigate the effect of spin-triplet $p$-wave pairing symmetry on the
superconducting excitations, resulting in Andreev reflection process and
Andreev bound state in the corresponding normal-superconductor (NS) and
superconductor-normal-superconductor (SNS) structures, respectively. We study
how the resulting subgap conductance and Josephson current are affected by the
particular symmetry of order parameter. The signature of $p_x$-wave symmetry is
found to decline the subgap superconducting energy excitations and,
consequently, slightly suppress the Andreev reflection in the case of $p$-doped
S region. The essential dynamical parameters $\lambda$ and $\beta$ of $MoS_2$
have significant effect on the both tunneling conductance and Josephson
current. Particularly, the considered $p$-wave symmetry in the superconducting
bound energies may feature the zero energy states at the interfaces. The
critical current oscillations as a function of length of junction are obtained
in the $p$-doped S region.


title:
Nematic orders and nematicity-driven topological phase transition in
  FeSe

abstract:
  We investigate nematic states in both bulk FeSe and FeSe thin films. It is
found that their band structures and signature features that were observed in a
variety of experiments can be perfectly explained by introducing the $d$-wave
nematic orders that are required to have contributions from all $t_{2g}$
d-orbitals, which contradicts the conventional wisdom that the nematicity is
simply driven by the orbital degeneracy between the $d_{xz}$ and $d_{yz}$
orbitals. These orders can be generated by the Coulomb interaction between the
nearest neighbor Fe sites. In the presence of spin-orbital couplings, we
predict that the nematic order can drive a topological quantum phase transition
through a band inversion at the $M$ point of the Brillouin zone to produce
topologically protected edge states near the Fermi level. The prediction makes
FeSe as a tunable system to integrate topological properties into high
temperature superconductivity to realize Majorana related physics.