title:
One-dimensional frustrated plaquette compass model: Nematic phase and
  spontaneous multimerization

abstract:
  We introduce a one-dimensional (1D) pseudospin model on a ladder where the
Ising interactions along the legs and along the rungs alternate between
$X_{i}X_{i+1}$ and $Z_{i}Z_{i+1}$ for even/odd bond (rung). We include also the
next nearest neighbor Ising interactions on plaquettes' diagonals that
alternate in such a way that a model where only leg interactions are switched
on is equivalent to the one when only the diagonal ones are present. Thus in
the absence of rung interactions the model can interpolate between two 1D
compass models. The model posses local symmetries which are the parities within
each $2\times 2$ cell (plaquette) of the ladder. We find that for different
values of the interaction it can realize ground states that differ by the
patterns formed by these local parities. By exact diagonalization we derive
detailed phase diagrams for small systems of $L=4$, 6 and 8 plaquettes, and use
next $L=12$ to identify generic phases that appear in larger systems as well.
Among them we find a nematic phase with macroscopic degeneracy when the leg and
diagonal interactions are equal and the rung interactions are larger than a
critical value. The nematic phase is similar to the one found in the
two-dimensional compass model. For particular parameters the low-energy sector
of the present plaquette model reduces to a 1D compass model with spins $S=1$
which suggests that it realizes peculiar crossovers within the class of compass
models. Finally, we show that the model can realize phases with broken
translation invariance which can be either dimerized, trimerized,
\textit{etcetera}, or completely disordered and highly entangled in a~well
identified window of the phase diagram.


title: Discovering Causal Signals in Images

abstract:
  This paper establishes the existence of observable footprints that reveal the
"causal dispositions" of the object categories appearing in collections of
images. We achieve this goal in two steps. First, we take a learning approach
to observational causal discovery, and build a classifier that achieves
state-of-the-art performance on finding the causal direction between pairs of
random variables, given samples from their joint distribution. Second, we use
our causal direction classifier to effectively distinguish between features of
objects and features of their contexts in collections of static images. Our
experiments demonstrate the existence of a relation between the direction of
causality and the difference between objects and their contexts, and by the
same token, the existence of observable signals that reveal the causal
dispositions of objects.


title:
Structural balance and opinion separation in trust-mistrust social
  networks

abstract:
  Structural balance theory has been developed in sociology and psychology to
explain how interacting agents, e.g., countries, political parties, opinionated
individuals, with mixed trust and mistrust relationships evolve into polarized
camps. Recent results have shown that structural balance is necessary for
polarization in networks with fixed, strongly connected neighbor relationships
when the opinion dynamics are described by DeGroot-type averaging rules. We
develop this line of research in this paper in two steps. First, we consider
fixed, not necessarily strongly connected, neighbor relationships. It is shown
that if the network includes a strongly connected subnetwork containing
mistrust, which influences the rest of the network, then no opinion clustering
is possible when that subnetwork is not structurally balanced; all the opinions
become neutralized in the end. In contrast, it is shown that when that
subnetwork is indeed structurally balanced, the agents of the subnetwork evolve
into two polarized camps and the opinions of all other agents in the network
spread between these two polarized opinions. Second, we consider time-varying
neighbor relationships. We show that the opinion separation criteria carry over
if the conditions for fixed graphs are extended to joint graphs. The results
are developed for both discrete-time and continuous-time models.


title:
Fano-Agarwal couplings and non-rotating wave approximation in
  single-photon timed-Dicke subradiance

abstract:
  Recently a new class of single-photon timed-Dicke (TD) subradiant states has
been introduced with possible applications in single-photon based quantum
information storage and on demand ultrafast retrieval [Scully M. O., Phys. Rev.
Lett., 115 (2015) 243602]. However, the influence of any kind of virtual
processes on the decay of these new kind of subradiant states has been left as
an open question. In the present paper, we focus on this problem in detail. In
particular, we investigate how pure Fano-Agarwal couplings and other virtual
processes arising from non-rotating wave approximation impact the decay of
otherwise sub and superradiant states. In addition to the overall virtual
couplings among all TD states, we also focus on the dominant role played by the
couplings between specific TD states.


title:
Strong coupling optical spectra in dipole-dipole interacting
  optomechanical Tavis-Cummings models

abstract:
  We theoretically investigate the emission spectrum of an optomechanical
Tavis-Cummings model: two dipole-dipole interacting atoms coupled to an
optomechanical cavity (OMC). In particular, we study the influence of
dipole-dipole interaction (DDI) on the single-photon spectrum emitted by this
hybrid system in the presence of a strong atom-cavity as well as strong
optomechanical interaction (hereinafter called the strong-strong coupling). We
also show that our analysis is amenable to inclusion of mechanical losses
(under the weak mechanical damping limit) and single-photon loss through
spontaneous emission from the two-level emitters under a non-local Lindblad
model.


title: 750 GeV diphoton excess confronted with a top-pion in the TTM model

abstract:
  The latest LHC data suggest an intriguing excess at $m_{\gamma\gamma} = 750$
GeV which apparently requires an explanation from the beyond standard model
physics. In this note we explore the possibility for this signal to arise from
a top-pion in the Top Triangle Moose model which can be viewed as a
dimensional-deconstruction version of the top-color assisted technicolor model.
We demonstrate that the observed excess can be accommodated by and has
important implications for this interesting model.


title:
Acceleration of the universe: a reconstruction of the effective equation
  of state

abstract:
  The present work is based upon a parametric reconstruction of the effective
or total equation of state in a model for the universe with accelerated
expansion. The constraints on the model parameters are obtained by maximum
likelihood analysis using the supernova distance modulus data, observational
Hubble data, baryon acoustic oscillation data and cosmic microwave background
shift parameter data. For statistical comparison, the same analysis has also
been carried out for the wCDM dark energy model. Different model selection
criteria (Akaike information criterion (AIC)) and (Bayesian Information
Criterion (BIC)) give the clear indication that the reconstructed model is well
consistent with the wCDM model. Then both the models (w_{eff}(z) model and wCDM
model) have also been presented through (q_0 ,j_0 ) parameter space. Tighter
constraint on the present values of dark energy equation of state parameter
(w_{DE}(z = 0)) and cosmological jerk (j_0) have been achieved for the
reconstructed model.


title: Ruling Out Static Latent Homophily in Citation Networks

abstract:
  Citation and coauthor networks offer an insight into the dynamics of
scientific progress. We can also view them as representations of a causal
structure, a logical process captured in a graph. From a causal perspective, we
can ask questions such as whether authors form groups primarily due to their
prior shared interest, or if their favourite topics are 'contagious' and spread
through co-authorship. Such networks have been widely studied by the artificial
intelligence community, and recently a connection has been made to nonlocal
correlations produced by entangled particles in quantum physics -- the impact
of latent hidden variables can be analyzed by the same algebraic geometric
methodology that relies on a sequence of semidefinite programming (SDP)
relaxations. Following this trail, we treat our sample coauthor network as a
causal graph and, using SDP relaxations, rule out latent homophily as a
manifestation of prior shared interest leading to the observed patternedness.
By introducing algebraic geometry to citation studies, we add a new tool to
existing methods for the analysis of content-related social influences.


title:
Exclusive vector meson production with a leading neutron in photon -
  hadron interactions at hadronic colliders

abstract:
  In this paper we study leading neutron production in photon - hadron
interactions which take place in $pp$ and $pA$ collisions at large impact
parameters. Using a model that describes the recent leading neutron data at
HERA, we consider exclusive vector meson production in association with a
leading neutron in $pp/pA$ collisions at RHIC and LHC energies. The total cross
sections and rapidity distributions of $\rho$, $\phi$ and $J/\Psi$ produced
together with a leading neutron are computed. Our results indicate that the
study of these processes is feasible and that it can be used to improve the
understanding of leading neutron processes and of exclusive vector meson
production.


title: The Symbolic Interior Point Method

abstract:
  A recent trend in probabilistic inference emphasizes the codification of
models in a formal syntax, with suitable high-level features such as
individuals, relations, and connectives, enabling descriptive clarity,
succinctness and circumventing the need for the modeler to engineer a custom
solver. Unfortunately, bringing these linguistic and pragmatic benefits to
numerical optimization has proven surprisingly challenging. In this paper, we
turn to these challenges: we introduce a rich modeling language, for which an
interior-point method computes approximate solutions in a generic way. While
logical features easily complicates the underlying model, often yielding
intricate dependencies, we exploit and cache local structure using algebraic
decision diagrams (ADDs). Indeed, standard matrix-vector algebra is efficiently
realizable in ADDs, but we argue and show that well-known optimization methods
are not ideal for ADDs. Our engine, therefore, invokes a sophisticated
matrix-free approach. We demonstrate the flexibility of the resulting
symbolic-numeric optimizer on decision making and compressed sensing tasks with
millions of non-zero entries.


title: Learning Multivariate Log-concave Distributions

abstract:
  We study the problem of estimating multivariate log-concave probability
density functions. We prove the first sample complexity upper bound for
learning log-concave densities on $\mathbb{R}^d$, for all $d \geq 1$. Prior to
our work, no upper bound on the sample complexity of this learning problem was
known for the case of $d>3$. In more detail, we give an estimator that, for any
$d \ge 1$ and $\epsilon>0$, draws $\tilde{O}_d \left( (1/\epsilon)^{(d+5)/2}
\right)$ samples from an unknown target log-concave density on $\mathbb{R}^d$,
and outputs a hypothesis that (with high probability) is $\epsilon$-close to
the target, in total variation distance. Our upper bound on the sample
complexity comes close to the known lower bound of $\Omega_d \left(
(1/\epsilon)^{(d+1)/2} \right)$ for this problem.


title:
X-ray observations of dust obscured galaxies in the Chandra Deep Field
  South

abstract:
  We present the properties of X-ray detected dust obscured galaxies (DOGs) in
the Chandra Deep Field South. In recent years, it has been proposed that a
significant percentage of the elusive Compton-thick (CT) active galactic nuclei
(AGN) could be hidden among DOGs. In a previous work, we presented the
properties of X-ray detected DOGs by making use of the deepest X-ray
observations available at that time, the 2Ms observations of the Chandra deep
fields. In that work, we only found a moderate percentage ($<$ 50%) of CT AGN
among the DOGs sample, but we were limited by poor photon statistics. In this
paper, we use not only a deeper 6 Ms Chandra survey of the Chandra Deep Field
South (CDF-S), but combine these data with the 3 Ms XMM-Newton survey of the
CDF-S. We also take advantage of the great coverage of the CDF-S region from
the UV to the far-IR to fit the spectral energy distributions (SEDs) of our
sources. Out of the 14 AGN composing our sample, 9 are highly absorbed (but
only 3 could be CT AGN), whereas 2 look unabsorbed, and the other 3 are only
moderately absorbed. In only one of the CT AGN, we detect a strong Fe K$\alpha$
emission line; the source is already classified as a CT AGN with Chandra data
in a previous work. For the other two CT candidates, the non-detection of the
line could be because of the low number of counts in their X-ray spectra, but
their location in the L$_{\rm 2-10\,keV}$/L$_{12\mu m}$ plot supports their CT
classification. Although a higher number of CT sources could be hidden among
the X-ray undetected DOGs, our results indicate that DOGs could be as well
composed of only a fraction of CT AGN plus a number of moderate to highly
absorbed AGN, as previously suggested. From our study of the X-ray undetected
DOGs in the CDF-S, we estimate a percentage between 13 and 44% of CT AGN among
the whole population of DOGs.


title: Weak boson production from D0 and LHCb in the NNPDF global analysis

abstract:
  High-precision electroweak production measurements from the Tevatron and the
LHC provide important constraints on the quark flavor separation in global PDF
fits. In this contribution, we study the impact of the recent D0 W asymmetry
measurements and of the LHCb W and Z Run I combination in the global NNPDF
analysis. We find that these measurements can be described by NLO QCD theory
and that they lead to a significant reduction of PDF uncertainties.


title:
A macroscopic traffic flow model with phase transitions and local point
  constraints on the flow

abstract:
  The two phase model for vehicular traffic flows recently appeared in
\cite{goatin2006aw} and \cite{BenyahiaRosini01} is endowed with a point
constraint on the flow to allow for the modelling of phenomena such as the
effects of toll booths along a road. We describe in this paper two Riemann
solvers for this model upon which an ulterior study of the cauchy problem
should rely.


title: Classical Electrodynamics in a Unified Theory

abstract:
  Some consequences of a fully classical unified theory of gravity and
electromagnetism are worked out for the electromagnetic sector such as the
occurrence of classical light beams with spin and orbital angular momenta that
are topologically quantized in units of $q_e q_m=\sigma$, independent of the
beam size. Empirical fits require $\sigma = \hbar$. The theory also predicts a
generalized coherency matrix whose consequences are testable.


title:
Handling magnetic anisotropy and dynamic magnetic response of
  ferromagnetic multilayers in flexible substrates

abstract:
  We investigate the dynamic magnetic response of ferromagnetic flexible
NiFe/Ta and FeCuNbSiB/Ta multilayers under external stress. We explore the
possibility of handling magnetic anisotropy and dynamic magnetic response of
flexible magnetostrictive nanostructures. We quantify the sensitivity of the
multilayers under external stress by calculating the ratio $|\Delta
\textrm{MI}|/|\Delta \bar{\sigma}|$ and show that considerable values can be
reached by tuning the magnetic field, frequency, magnetostriction constant, and
external stress. The results reveal possibilities of application of flexible
magnetostrictive multilayers under external stress and place them as very
attractive candidates as element sensor for the development of sensitive smart
touch sensors.


title: Analysis of Resparsification

abstract:
  We show that schemes for sparsifying matrices based on iteratively resampling
rows yield guarantees matching classic 'offline' sparsifiers (see e.g. Spielman
and Srivastava [STOC 2008]).
  In particular, this gives a formal analysis of a scheme very similar to the
one proposed by Kelner and Levin [TCS 2013].


title:
Thickness and temperature dependence of the magnetodynamic damping of
  pulsed laser deposited $\text{La}_{0.7}\text{Sr}_{0.3}\text{MnO}_3$ on
  (111)-oriented SrTi$\text{O}_3$

abstract:
  We have investigated the magnetodynamic properties of
$\text{La}_{0.7}\text{Sr}_{0.3}\text{MnO}_3$ (LSMO) films of thickness 10, 15
and 30 nm grown on (111)-oriented SrTi$\text{O}_3$ (STO) substrates by pulsed
laser deposition. Ferromagnetic resonance (FMR) experiments were performed in
the temperature range 100--300 K, and the magnetodynamic damping parameter
$\alpha$ was extracted as a function of both film thickness and temperature. We
found that the damping is lowest for the intermediate film thickness of 15 nm
with $\alpha \approx 2 \cdot 10^{-3}$, where $\alpha$ is relatively constant as
a function of temperature well below the Curie temperature of the respective
films.


title: Free Group Rings and Derived Functors

abstract:
  An approach to identify the normal subgroups determined by ideals in free
group rings with the help of the derived functors of non-additive functors is
explored. A similar approach, i.e., via derived functors, for computing limits
of functors from the category of free presentations to the category of abelian
groups, arising from commutator structure of free groups, is also discussed.


title: Centrality in the Global Network of Corporate Control

abstract:
  Corporations across the world are highly interconnected in a large global
network of corporate control. This paper investigates the global board
interlock network, covering 400,000 firms linked through 1,700,000 edges
representing shared directors between these firms. The main focus is on the
concept of centrality, which is used to investigate the embeddedness of firms
from a particular country within the global network. The study results in three
contributions. First, to the best of our knowledge for the first time we can
investigate the topology as well as the concept of centrality in corporate
networks at a global scale, allowing for the largest cross-country comparison
ever done in interlocking directorates literature. We demonstrate, amongst
other things, extremely similar network topologies, yet large differences
between countries when it comes to the relation between economic prominence
indicators and firm centrality. Second, we introduce two new metrics that are
specifically suitable for comparing the centrality ranking of a partition to
that of the full network. Using the notion of centrality persistence we propose
to measure the persistence of a partition's centrality ranking in the full
network. In the board interlock network, it allows us to assess the extent to
which the footprint of a national network is still present within the global
network. Next, the measure of centrality ranking dominance tells us whether a
partition (country) is more dominant at the top or the bottom of the centrality
ranking of the full (global) network. Finally, comparing these two new measures
of persistence and dominance between different countries allows us to classify
these countries based the their embeddedness, measured using the relation
between the centrality of a country's firms on the national and the global
scale of the board interlock network.


title: On lengths of HZ-localization towers

abstract:
  In this paper, the $H\mathbb Z$-length of different groups is studied. By
definition, this is the length of $H\mathbb Z$-localization tower or the length
of transfinite lower central series of $H\mathbb Z$-localization. It is proved
that, for a free noncyclic group, its $H\mathbb Z$-length is $\geq \omega+2$.
For a large class of $\mathbb Z[C]$-modules $M,$ where $C$ is an infinite
cyclic group, it is proved that the $H\mathbb Z$-length of the semi-direct
product $M\rtimes C$ is $\leq \omega+1$ and its $H\mathbb Z$-localization can
be described as a central extension of its pro-nilpotent completion. In
particular, this class covers modules $M$, such that $M\rtimes C$ is finitely
presented and $H_2(M\rtimes C)$ is finite.


title: Adiabatic preparation of Floquet condensates

abstract:
  We argue that a Bose-Einstein condensate can be transformed into a Floquet
condensate, that is, into a periodically time-dependent many-particle state
possessing the coherence properties of a mesoscopically occupied
single-particle Floquet state. Our reasoning is based on the observation that
the denseness of the many-body system's quasienergy spectrum does not
necessarily obstruct effectively adiabatic transport. Employing the idealized
model of a driven bosonic Josephson junction, we demonstrate that only a small
amount of Floquet entropy is generated when a driving force with judiciously
chosen frequency and maximum amplitude is turned on smoothly.


title: Entropy production within a pulsed Bose-Einstein condensate

abstract:
  We suggest to subject anharmonically trapped Bose-Einstein condensates to
sinusoidal forcing with a smooth, slowly changing envelope, and to measure the
coherence of the system after such pulses. In a series of measurements with
successively increased maximum forcing strength one then expects an adiabatic
return of the condensate to its initial state as long as the pulses remain
sufficiently weak. In contrast, once the maximum driving amplitude exceeds a
certain critical value there should be a drastic loss of coherence, reflecting
significant heating induced by the pulse. This predicted experimental signature
is traced to the loss of an effective adiabatic invariant, and to the ensuing
breakdown of adiabatic motion of the system's Floquet state when the many-body
dynamics become chaotic. Our scenario is illustrated with the help of a
two-site model of a forced bosonic Josephson junction, but should also hold for
other, experimentally accessible configurations.


title:
Towards optimal nonlinearities for sparse recovery using higher-order
  statistics

abstract:
  We consider machine learning techniques to develop low-latency approximate
solutions to a class of inverse problems. More precisely, we use a
probabilistic approach for the problem of recovering sparse stochastic signals
that are members of the $\ell_p$-balls. In this context, we analyze the
Bayesian mean-square-error (MSE) for two types of estimators: (i) a linear
estimator and (ii) a structured estimator composed of a linear operator
followed by a Cartesian product of univariate nonlinear mappings. By
construction, the complexity of the proposed nonlinear estimator is comparable
to that of its linear counterpart since the nonlinear mapping can be
implemented efficiently in hardware by means of look-up tables (LUTs). The
proposed structure lends itself to neural networks and iterative
shrinkage/thresholding-type algorithms restricted to a single iterate (e.g. due
to imposed hardware or latency constraints). By resorting to an alternating
minimization technique, we obtain a sequence of optimized linear operators and
nonlinear mappings that converge in the MSE objective. The result is attractive
for real-time applications where general iterative and convex optimization
methods are infeasible.


title:
Classical probability density distributions with uncertainty relations
  for ground states of simple non-relativistic quantum-mechanical systems

abstract:
  The probability density distributions for the ground states of certain model
systems in quantum mechanics and for their classical counterparts are
considered. It is shown, that classical distributions are remarkably improved
by incorporating into them the Heisenberg uncertainty relation between position
and momentum. Even the crude form of this incorporation makes the agreement
between classical and quantum distributions unexpectedly good, except for the
small area, where classical momenta are large. It is demonstrated that the
slight improvement of this form, makes the classical distribution very similar
to the quantum one in the whole space. The obtained results are much better
than those from the WKB method. The paper is devoted to ground states, but the
method applies to excited states too.


title: Connections in holomorphic Lie algebroids

abstract:
  The main purpose of this note is the study of the total space of a
holomorphic Lie algebroid $E$. The paper is structured in three parts.
  In the first section we briefly introduce basic notions on holomorphic Lie
algebroids. The local expressions are written and the complexified holomorphic
bundle is introduced.
  The second section is a little broader and includes two approaches to study
the geometry of complex manifold $E.$ The first part contains the study of the
tangent bundle $T_{C}E=T^{\prime }E\oplus T^{\prime \prime }E$ and its link,
via tangent anchor map, with the complexified tangent bundle $% T_{C}(T^{\prime
}M)=T^{\prime }(T^{\prime }M)\oplus T^{\prime \prime }(T^{\prime }M).$ A
holomorphic Lie algebroid structure has been emphasized on $T^{\prime }E.$ A
special study is made for integral curves of a spray on $% T^{\prime }E.$
Theorem 2.1 gives the coefficients of a spray, called canonical, according to a
complex Lagrangian on $T^{\prime }E.$ In the second part of section two we
study the prolongation $\mathcal{T}% ^{\prime }E$ of $E\times T^{\prime }E$
algebroid structure.
  In the third section we study how a complex Lagrange (Finsler) structure on
$T^{\prime }M$ induces a Lagrangian structure on $E.$ Three particular cases
are analyzed by the rank of anchor map, the dimensions of manifold $M$ and the
fibre dimension. We obtain the correspondent on $E$ of the well-known
(\cite{Mu}) Chern-Lagrange nonlinear connection from $T^{\prime }M$.


title: On the Krull Intersection Theorem in Function Algebras

abstract:
  A version of the Krull Intersection Theorem states that for Noetherian
domains, the Krull intersection $ki(I)$ of every proper ideal $I$ is trivial;
that is $$ ki(I):=\displaystyle\bigcap_{n=1}^\infty I^n = \{0\}. $$ We
investigate the validity of this result for various function algebras $R$,
present ideals $I$ of $R$ for which $ ki(I)\neq \{0\}$, and give conditions on
$I$ so that $ki(I)=\{0\}$.


title:
Analysis of global Terrestrial Gamma Ray Flashes distribution and
  special focus on AGILE detections over South America

abstract:
  Global distribution of the Terrestrial Gamma-ray Flashes (TGFs) detected by
AGILE and RHESSI for the period from March 2009 to July 2012 has been analysed.
A fourth TGF production region has been distinguished over the Pacific. It is
confirmed that TGF occurrence follows the Intertropical Convergence Zone(ITCZ)
seasonal migration and prefers afternoons. TGF/lightning ratio appears to be
lower over America than other regions suggesting that meteorological regional
differences are important for the TGF production. Diurnal cycle of TGFs peaks
in the afternoon suggesting that Convective Available Potential Energy (CAPE)
and convection are important for TGF production. Moreover all AGILE passages
over South America in the same period have been analysed to find meteorological
preferences for TGF occurrence. In each passage the analysis of Cloud Top
Altitude (CTA), CAPE, number of strokes, number of storms and coverage area of
clouds with temperatures below $-70\,^{\circ}{\rm C}$ (Cloud Top Coverage area,
CTC) are computed. On average, AGILE has been exposed to 19,100 strokes between
each TGF representing $\sim$68 hours of exposure over active storms. High CAPE
values, high cloud tops and high stroke occurrence suggests that meteorological
conditions conducive to vigorous and electrically active storms are important
for TGF production. It is shown that a high number of thunderstorms is
preferable for TGF production which may be explained by a greater chance of the
presence of a thunderstorm in the best development stage for TGF production.
High tropopause altitude seems to be important but not primordial for TGF
production.


title: Eigenvalue problem for a p-Laplacian equation with trapping potentials

abstract:
  Consider the following eigenvalue problem of p-Laplacian equation
\begin{equation}\label{P}
  -\Delta_{p}u+V(x)|u|^{p-2}u=\mu|u|^{p-2}u+a| u|^{s-2}u, x\in \mathbb{R}^{n},
\tag{P} \end{equation} where $a\geq0$, $p\in (1,n)$ and $\mu\in\mathbb{R}$.
$V(x)$ is a trapping type potential, e.g., $\inf\limits_{x \in
\mathbb{R}^n}V(x)< \lim\limits_{|x|\rightarrow+\infty}V(x)$. By using
constrained variational methods, we proved that there is $a^*>0$, which can be
given explicitly, such that problem (\ref{P}) has a ground state $u$ with
$\|u\|_{L^p}=1$ for some $\mu \in \mathbb{R}$ and all $a\in [0,a^*)$, but
(\ref{P}) has no this kind of ground state if $a\geq a^*$. Furthermore, by
establishing some delicate energy estimates we show that the global maximum
point of the ground states of problem (\ref{P}) approach to one of the global
minima of $V(x)$ and blow up if $a\nearrow a^*$. The optimal rate of blowup is
obtained for $V(x)$ being a polynomial type potential.


title:
Two-dimensional Fr\"ohlich interaction in transition-metal
  dichalcogenide monolayers: Theoretical modeling and first-principles
  calculations

abstract:
  We perform ab initio calculations of the coupling between electrons and
small-momentum polar-optical phonons in monolayer transition metal
dichalcogenides of the 2H type: MoS2, MoSe2, MoTe2, WS2, and WSe2. The
so-called Fr\"ohlich interaction is fundamentally affected by the
dimensionality of the system. In a plane-wave framework with periodic boundary
conditions, this coupling is affected by the spurious interaction between the
2D material and its periodic images. To overcome this, we perform density
functional perturbation theory calculations with a truncated Coulomb
interaction in the out-of-plane direction. We show that the 2D Fr\"ohlich
interaction is much stronger than assumed in previous ab initio studies. We
provide analytical models depending on the effective charges and dielectric
properties of the materials to interpret our ab initio calculations. Screening
is shown to play a fundamental role in the phonon-momentum dependency of the
polar-optical coupling, with a crossover between two regimes depending on the
dielectric properties of the material relative to its environment. The
Fr\"ohlich interaction is screened by the dielectric environment in the limit
of small phonon momenta and sharply decreases due to stronger screening by the
monolayer at finite momenta. The small-momentum regime of the ab initio
Fr\"ohlich interaction is reproduced by a simple analytical model, for which we
provide the necessary parameters. At larger momenta, however, direct ab initio
calculations of electron-phonon interactions are necessary to capture
band-specific effects. We compute and compare the carrier relaxation times
associated to the scattering by both LO and A1 phonon modes. While both modes
are capable of relaxing carriers on timescales under the picosecond at room
temperature, their absolute and relative importance vary strongly depending on
the material, the band, and the substrate.


title:
Implications of N=5, 6 superconformal symmetry in three spacetime
  dimensions

abstract:
  For general N=5 and N=6 superconformal field theories in three dimensions, we
compute the three-point correlation functions of the supercurrent multiplets.
In each case, N=5 and N=6, the functional form of this correlator is uniquely
fixed modulo an overall coefficient which is related, by superconformal Ward
identities, to the parameter in the two-point function of the supercurrent. The
structure of the correlation functions obtained is consistent with the property
that every N=5 superconformal field theory, considered as a special N=4 theory,
is invariant under the mirror map.


title:
The Shape of Dark Matter Haloes, V. Analysis of observations of edge-on
  galaxies

abstract:
  In the previous papers in this series, we have measured the stellar and \hi
content in a sample of edge-on galaxies. In the present paper, we perform a
simultaneous rotation curve and vertical force field gradient decomposition for
five of these edge-on galaxies. The rotation curve decomposition provides a
measure of the radial dark matter potential, while the vertical force field
gradient provide a measure of the vertical dark matter potential. We fit dark
matter halo models to these potentials. Using our \hi self-absorption results,
we find that a typical dark matter halo has a less dense core
($0.094\pm0.230$\,M$_\odot$/pc$^3$) compared to an optically thin \hi model
($0.150\pm0.124$\,M$_\odot$/pc$^3$). The HI self-absorption dark matter halo
has a longer scale length $R_c$ of $1.42\pm 3.48$\,kpc, versus $1.10\pm
1.81$\,kpc for the optically thin HI model. The median halo shape is spherical,
at $q=1.0\pm0.6$ (self-absorbing \hi), while it is prolate at $q=1.5\pm0.6$ for
the optically thin. Our best results were obtained for ESO\,274-G001 and
UGC\,7321, for which we were able to measure the velocity dispersion in Paper
III. These two galaxies have drastically different halo shapes, with one oblate
and one strongly prolate. Overall, we find that the many assumptions required
make this type of analysis susceptible to errors.


title:
Long-range and short-range magnetic correlations, and microscopic origin
  of net magnetization in the spin-1 trimer chain compound CaNi3P4O14

abstract:
  Spin-spin correlations and microscopic origin of net magnetization in the
spin-1 trimer chain compound CaNi3P4O14 have been investigated by powder
neutron diffraction. The present study reveals a 3D long-range magnetic
ordering below 16 K where the magnetic structure consists of ferromagnetic
trimers that are coupled ferromagnetically along the spin-chain. The moment
components along the a and c axes arrange antiferromagnetically. Our study
establishes that the uncompensated moment components along the b axis result in
a net magnetization per unit cell. The magnetic structure, determined in the
present study, is in agreement with the results of recent first principles
calculation; however, it is in contrast to a fascinating experimental
prediction of ferrimagnetic ordering based on the periodicity of the exchange
interactions in CaNi3P4O14. Our study also confirms the presence of broad
diffuse magnetic scattering, due to 1D short-range spin-spin correlations, over
a wide temperature range below ~50 K down to a temperature well below the Tc.
Total neutron scattering analysis by the RMC method reveals that the dominating
spin-spin correlation above Tc is ferromagnetic and along the b axis. The
nearest neighbour spin-spin correlations along the a and c axes are found to be
weakly antiferromagnetic. The nature of the trimer spin structure of the
short-range state is similar to that of the 3D long-range ordered state. The
present investigation of microscopic nature of the magnetic ground state also
explains the condition required for the 1/3 magnetization plateau to be
observed in the trimer spin-chains. In spite of the S=1 trimer chain system,
the present compound CaNi3P4O14 is found to be a good realization of 3D magnet
below the Tc=16 K with full ordered moment values of ~2 mu_B/Ni2+ (1.98 and
1.96 mu_B/Ni2+ for two Ni sites, respectively) at 1.5 K.


title: Single-shot simulations of dynamics of quantum dark solitons

abstract:
  Eigenstates of Bose particles with repulsive contact interactions in
one-dimensional space with periodic boundary conditions can be found with the
help of the Bethe ansatz. The type~II excitation spectrum identified by E. H.
Lieb, reproduces the dispersion relation of dark solitons in the mean-field
approach. The corresponding eigenstates possess translational symmetry which
can be broken in measurements of positions of particles. We analyze emergence
of single and double solitons in the course of the measurements and investigate
dynamics of the system. In the weak interaction limit, the system follows the
mean-field prediction for a short period of time. Long time evolution reveals
many-body effects that are related to an increasing uncertainty of soliton
positions. In the strong interaction regime particles behave like impenetrable
bosons. Then, the probability densities in the configuration space become
identical to the probabilities of non-interacting fermions but the
wave-functions themselves remember the original Bose statistics. Especially,
the phase flips that are key signatures of the solitons in the weak interaction
limit, can be observed in the time evolution of the strongly interacting
bosons.


title:
Energy levels and radiative rates for transitions in Fe V, Co VI and Ni
  VII

abstract:
  Energy levels, Land\'{e} $g$-factors and radiative lifetimes are reported for
the lowest 182 levels of the 3d$^4$, 3d$^3$4s and 3d$^3$4p configurations of
Fe~V, Co~VI and Ni~VII. Additionally, radiative rates ($A$-values) have been
calculated for the E1, E2 and M1 transitions among these levels. The
calculations have been performed in a quasi-relativistic approach (QR) with a
very large {\em configuration interaction} (CI) wavefunction expansion, which
has been found to be necessary for these ions. Our calculated energies for all
ions are in excellent agreement with the available measurements, for most
levels. Discrepancies among various calculations for the radiative rates of E1
transitions in Fe~V are up to a factor of two for stronger transitions ($f \geq
0.1$), and larger (over an order of magnitude) for weaker ones. The reasons for
these discrepancies have been discussed and mainly are due to the differing
amount of CI and methodologies adopted. However, there are no appreciable
discrepancies in similar data for M1 and E2 transitions, or the $g$-factors for
the levels of Fe~V, the only ion for which comparisons are feasible.


title:
Low energy physics of the t-J model in $d=\infty$ using Extremely
  Correlated Fermi Liquid theory: Cutoff Second Order Equations

abstract:
  We present the results for the low energy properties of the infinite
dimensional t-J model with $J=0$, using $O(\lambda^2)$ equations of the
extremely correlated Fermi liquid formalism. The parameter $\lambda \in [0,1]$
is analogous to the inverse spin parameter $1/(2S)$ in quantum magnets. The
present analytical scheme allows us to approach the physically most interesting
regime near the Mott insulating state $n\lesssim 1$. It overcomes the
limitation to low densities $n \lesssim .7$ of earlier calculations, by
employing a variant of the skeleton graph expansion, and a high frequency
cutoff that is essential for maintaining the known high-T entropy. The
resulting quasiparticle weight $Z$, the low $\omega,T $ self energy and the
resistivity are reported. These are quite close at all densities to the exact
numerical results of the $U=\infty$ Hubbard model, obtained using the dynamical
mean field theory. The present calculation offers the advantage of generalizing
to finite $T$ rather easily, and allows the visualization of the loss of
coherence of Fermi liquid quasiparticles by raising $T$. The present scheme is
generalizable to finite dimensions and a non vanishing $J$.


title: Fully faithful Fourier-Mukai functors and generic vanishing

abstract:
  The aim of this mainly expository note is to point out that, given an
Fourier-Mukai functor, the condition making it fully faithful is an instance of
\emph{generic vanishing}. We test this point of view on some fairly classical
examples, including the strong simplicity criterion of Bondal and Orlov, the
standard flip and the Mukai flop.


title:
Shape vibrations and quasiparticle excitations in the lowest 0+ excited
  state of the Erbium isotopes

abstract:
  The ground and first excited 0+ states of the {156-172}Er isotopes are
analyzed in the framework of the generator coordinate method. The shape
parameter beta is used to generate wave functions with different deformations
which together with the two-quasiparticle states built on them provide a set of
states. An angular momentum and particle number projection of the latter spawn
the basis states of the generator coordinate method. With this ansatz and using
the separable pairing plus quadrupole interaction we obtain a good agreement
with the experimental spectra and E2 transition rates up to moderate spin
values. The structure of the wave functions suggests that the first excited 0+
states in the soft Er isotopes are dominated by shape fluctuations, while in
the well deformed Er isotopes the two-quasiparticle states are more relevant.
In between both degrees of freedom are necessary .


title: Critical behavior of cross sections at LHC

abstract:
  Recent experimental data on elastic scattering of high energy protons show
that the critical regime has been reached at LHC energies. The approach to
criticality is demonstrated by increase of the ratio of elastic to total cross
sections from ISR to LHC energies. At LHC it reaches the value which can result
in principal change of the character of proton interactions. The treatment of
new physics of hollowed toroid-like hadrons requires usage of another branch of
the unitarity condition. Its further fate is speculated and interpreted with
the help of the unitarity condition in combination with present experimental
data. The gedanken experiments to distinguish between different possibilities
are proposed.


title:
Fast suppression of superconductivity with Fe site Ni substitution in
  Fe1-xNixSe0.5Te0.5 (x=0.0, 0.01, 0.03, 0.05, 0.07, 0.10 and 0.20) single
  crystals

abstract:
  We report the effect of Ni doping on superconductivity of FeSe0.5Te0.5. The
single crystal samples of series Fe1-xNixSe0.5Te0.5 (x=0.0, 0.01, 0.03, 0.05,
0.07, 0.10 and 0.20) are synthesized via vacuum shield solid state reaction
route and high temperature heating followed by slow cooling. All the crystals
of Fe1-xNixSe0.5Te0.5 series with x up to 0.20, i.e., 20% substitution of Ni at
Fe site are crystallized in single phase tetragonal structure with space group
P4/nmm. The electrical resistivity measurements revealed that Tc decreases fast
with increase of Ni concentration in Fe1-xNixSe0.5Te0.5. Namely the
superconducting transition temperature (Tc) being defined as resistivity =0
decrease from 12K to around 4K and 2K for x=0.01 and 0.03 samples respectively.
For x=0.05 (5at% Ni at Fe site) though Tconset is observed in resistivity
measurements but \r{ho}=0 is not seen down to 2K. For x more than 0.07, neither
the Tconset nor Tc\r{ho}=0 is seen down 2K in R-T measurements. It is
demonstrated that Ni doping at Fe site in FeSe0.5Te0.5 superconductor
suppresses superconductivity fast. The rate of Tc depression is albeit non
monotonic. Summarily, a systematic study on suppression of superconductivity
with Fe site Ni doping in flux free gown FeSe0.5Te0.5 single crystals is
presented in the current communication.


title: Magnetic properties in the inhomogeneous chiral phase

abstract:
  We investigate the magnetic properties of quark matter in the inhomogeneous
chiral phase, where both scalar and pseudoscalar condensates spatially
modulate. The energy spectrum of the lowest Landau level becomes asymmetric
about zero in the external magnetic field, and gives rise to the remarkably
magnetic properties: quark matter has a spontaneous magnetization, while the
magnetic susceptibility does not diverge on the critical point.


title:
Butterfly Diagram and Carrington Maps for Century-Long Ca II K
  Spectroheliograms from Kodaikanal Observatory

abstract:
  The century-long (1907-2007) Ca II K spectroheliograms from Kodaikanal Solar
Observatory (KSO) are calibrated, processed and analysed in the present study
to follow the evolution of bright on disc structures called plages, the
possible representatives of magnetic activity on the Sun. This has been the
longest dataset studied in Ca II K till date covering about 9.5 cycles of 11
year periods. Plages were segmented with area $\geq 1\:\textrm {arcmin}^2$
using global thresholds for individual full disc images and subsequent
application of morphological closing operation. Plage index was calculated and
seen to have close positive correlation with fractional disc area covered by
plages. The newly generated plage area cycle (from KSO) was compared with the
same from Mount Wilson observatory (Correlation~$95.6\%$) for the overlapping
years i.e. 1915-2000. Study illustrated time-latitude distribution of plage
centroids rendering butterfly diagram (as observed for sunspots). The 3D
visualisation of the diagram showed one to one mapping between plage location,
time and area. This work further delineated positional correlation between
magnetic patches and plage regions through comparison of synoptic maps derived
from both Kodaikanal Ca II K images and space based full disc LOS (line of
sight) magnetograms. Regular synoptic magnetograms from ground based
observatories are available only after 1970s. Thus the long term Ca II K data
from KSO can be used as a proxy for estimating magnetic activity locations and
their strengths at earlier times.


title: Lepton flavor-violating decays of the Higgs boson from sgoldstino mixing

abstract:
  We study lepton flavor violation in a class of supersymmetric models with
light sgoldstino - scalar superpartner of Goldstone fermions responsible for
spontaneous supersymmetry breaking. Sgoldstino couplings to the Standard Model
(SM) fermions are determined by the MSSM soft terms and, in general, provide
with flavor violation in this sector. Sgoldstino admixture to the lightest
Higgs boson results in changes of its coupling constants and, in particular,
leads to lepton flavor-violating decay $h\to\tau\mu$ of the Higgs resonance. We
discuss viability and phenomenological consequences of this scenario.


title: Uniqueness of Minima of a Certain Least Squares Problem

abstract:
  This paper is essentially an exercise in studying the minima of a certain
least squares optimization using the second partial derivative test. The
motivation is to gain insight into an optimization-based solution to the
problem of tracking human limbs using IMU sensors.


title:
ICE: A General and Validated Energy Complexity Model for Multithreaded
  Algorithms

abstract:
  Like time complexity models that have significantly contributed to the
analysis and development of fast algorithms, energy complexity models for
parallel algorithms are desired as crucial means to develop energy efficient
algorithms for ubiquitous multicore platforms. Ideal energy complexity models
should be validated on real multicore platforms and applicable to a wide range
of parallel algorithms. However, existing energy complexity models for parallel
algorithms are either theoretical without model validation or
algorithm-specific without ability to analyze energy complexity for a
wide-range of parallel algorithms.
  This paper presents a new general validated energy complexity model for
parallel (multithreaded) algorithms. The new model abstracts away possible
multicore platforms by their static and dynamic energy of computational
operations and data access, and derives the energy complexity of a given
algorithm from its work, span and I/O complexity. The new model is validated by
different sparse matrix vector multiplication (SpMV) algorithms and dense
matrix multiplication (matmul) algorithms running on high performance computing
(HPC) platforms (e.g., Intel Xeon and Xeon Phi). The new energy complexity
model is able to characterize and compare the energy consumption of SpMV and
matmul kernels according to three aspects: different algorithms, different
input matrix types and different platforms. The prediction of the new model
regarding which algorithm consumes more energy with different inputs on
different platforms, is confirmed by the experimental results. In order to
improve the usability and accuracy of the new model for a wide range of
platforms, the platform parameters of ICE model are provided for eleven
platforms including HPC, accelerator and embedded platforms.


title:
A $f(R)$-gravity model of the Sunyaev-Zeldovich profile of the Coma
  cluster compatible with {\it Planck} data

abstract:
  In the weak field limit, analytic $f(R)$ models of gravity introduce a
Yukawa-like correction to the Newtonian gravitational potential. These models
have been widely tested at galactic scales and provide an alternative
explanation to the dynamics of galaxies without Dark Matter. We study if the
temperature anisotropies due to the thermal Sunyaev-Zeldovich effect are
compatible with these Extended Theories of Gravity. We assume that the gas is
in hydrostatic equilibrium within the modified Newtonian potential and it is
well described by a polytropic equation of state. We particularize the model
for the Coma cluster and the predicted anisotropies are compared with those
measured in the foreground cleaned maps obtained using the Planck Nominal maps
released in 2013. We show that the computed $f(R)$ pressure profile fits the
data giving rise to competitive constraints of the Yukawa scale length
$L=(2.19\pm1.02) \rm{\, Mpc}$, and of the deviation parameter $
\delta=-0.48\pm0.22$. Those are currently the tightest constraints at galaxy
cluster scale, and support the idea that Extended Theories of Gravity provide
an alternative explanation to the dynamics of self-gravitating systems without
requiring Dark Matter.


title:
Chebyshev polynomial coefficient bounds for a subclass of bi-univalent
  functions

abstract:
  In this work, considering a general subclass of bi-univalent functions and
using the Chebyshev polynomials, we obtain coefficient expansions for functions
in this class.


title: Thermodynamic properties of black holes in de Sitter space

abstract:
  We study the thermodynamic properties of Schwarzschild-de Sitter (SdS) black
hole and Reissner-Nordstr\"{o}m-de Sitter (RNdS) black hole in the view of
global and effective thermodynamic quantities. Making use of the effective
first law of thermodynamics, we can derive the effective thermodynamic
quantities of de Sitter black holes. It is found that these effective
thermodynamic quantities also satisfy Smarr-like formula. Especially, the
effective temperatures are nonzero in the Nariai limit, which is consistent
with the idea of Bousso and Hawking. By calculating heat capacity and Gibbs
free energy, we find SdS black hole is always thermodynamically stable and RNdS
black hole may undergoes phase transition at some points.


title: Riemann-Hurwitz formula for finite morphisms of $p$-adic curves

abstract:
  Given a finite morphism $\varphi:Y\to X$ of quasi-smooth Berkovich curves
over a complete, algebraically closed field $k$ of characteristic $0$, we prove
a Riemann-Hurwitz formula relating their Euler-Poincar\'e characteristics
(calculated using De Rham cohomology of their overconvergent structure sheaf).
The main tools are $p$-adic Runge's theorem together with valuation polygons of
analytic functions. Using the results obtained, we provide another point of
view on Riemann-Hurwitz formula for finite morphisms of curves over
algebraically closed fields of positive characteristic.


title: MSSM without a free parameter

abstract:
  It is often argued that the minimal supersymmetric standard model has O(100)
free parameters and the generic parameter region is already excluded by the
null observation of the flavor and CP violating processes as well as the
constraints from the LHC experiments. This situation naturally leads us to
consider the case where all the dangerous soft supersymmetry breaking terms
such as the scalar masses and scalar couplings are absent, while only the
unified gaugino mass term and the mu term are non-vanishing at the grand
unification scale. We revisit this simple situation taking into account the
observed Higgs boson mass, 125 GeV. Since the gaugino mass and the mu term are
fixed in order to explain the Higgs boson and the Z boson masses, there is no
free parameter left in this scenario. We find that there are three independent
parameter sets exist including ones which have not been discussed in the
literature. We also find that the abundance of the dark matter can be explained
by relic gravitinos which are non-thermally produced as decay products of the
SUSY particles while satisfying constraints from Big Bang Nucleosynthesis. We
discuss the effects of the gravity mediation which generically give
contribution to the soft terms of the order of the gravitino mass. It turns out
that newly found parameter set is preferable to explain the Higgs boson mass as
well as the gravitino dark matter while satisfying the constraints from the
electric dipole moments of the electron and the nucleon.


title:
Predict or classify: The deceptive role of time-locking in brain signal
  classification

abstract:
  Several experimental studies claim to be able to predict the outcome of
simple decisions from brain signals measured before subjects are aware of their
decision. Often, these studies use multivariate pattern recognition methods
with the underlying assumption that the ability to classify the brain signal is
equivalent to predict the decision itself. Here we show instead that it is
possible to correctly classify a signal even if it does not contain any
predictive information about the decision. We first define a simple stochastic
model that mimics the random decision process between two equivalent
alternatives, and generate a large number of independent trials that contain no
choice-predictive information. The trials are first time-locked to the time
point of the final event and then classified using standard machine-learning
techniques. The resulting classification accuracy is above chance level long
before the time point of time-locking. We then analyze the same trials using
information theory. We demonstrate that the high classification accuracy is a
consequence of time-locking and that its time behavior is simply related to the
large relaxation time of the process. We conclude that when time-locking is a
crucial step in the analysis of neural activity patterns, both the emergence
and the timing of the classification accuracy are affected by structural
properties of the network that generates the signal.


title: Gaia FGK Benchmark Stars: New Candidates At Low-Metallicities

abstract:
  We have entered an era of large spectroscopic surveys in which we can
measure, through automated pipelines, the atmospheric parameters and chemical
abundances for large numbers of stars. Calibrating these survey pipelines using
a set of "benchmark stars" in order to evaluate the accuracy and precision of
the provided parameters and abundances is of utmost importance. The recent
proposed set of Gaia FGK benchmark stars of Heiter et al. (2015) has no
recommended stars within the critical metallicity range of $-2.0 <$ [Fe/H] $<
-1.0$ dex. In this paper, we aim to add candidate Gaia benchmark stars inside
of this metal-poor gap. We began with a sample of 21 metal-poor stars which was
reduced to 10 stars by requiring accurate photometry and parallaxes, and
high-resolution archival spectra. The procedure used to determine the stellar
parameters was similar to Heiter et al. (2015) and Jofre et al. (2014) for
consistency. The effective temperature (T$_{\mathrm{eff}}$) of all candidate
stars was determined using the Infrared Flux Method utilizing multi-band
photometry. The surface gravity (log g) was determined through fitting stellar
evolutionary tracks. The [Fe/H] was determined using four different
spectroscopic methods fixing the T$_{\mathrm{eff}}$ and log g from the values
determined independent of spectroscopy. We discuss, star-by-star, the quality
of each parameter including how it compares to literature, how it compares to a
spectroscopic run where all parameters are free, and whether Fe I
ionisation-excitation balance is achieved. From the 10 stars, we recommend a
sample of five new metal-poor benchmark candidate stars which have consistent
T$_{\mathrm{eff}}$ , log g, and [Fe/H] determined through several means. These
stars can be used for calibration and validation purpose of stellar parameter
and abundance pipelines and should be of highest priority for future
interferometric studies.


title: Phase relationships of solar hemispheric toroidal and poloidal cycles

abstract:
  The solar northern and southern hemispheres exhibit differences between the
intensities and time profiles of the activity cycles. The time variation of
these properties has been studied in a previous article on the data of Cycles
12-23. The hemispheric phase lags exhibited a characteristic variation: the
leading role has been exchanged between the hemispheres by four cycles. The
present work extends the investigation of this variation with the data of
Schwabe and Staudacher in Cycles 1-4 and 7-10 as well as Sp\"orer's data in
cycle 11. The previously found variation can not be clearly recognized using
the data of Staudacher, Schwabe and Sp\"orer. However, it is more interesting
that the phase lags of the reversals of the magnetic fields at the poles follow
the same variation as that of the hemispheric cycles in Cycles 12-23, i.e. in
four cyles one of the hemispheres leads and the leading role jumps to the
opposite hemisphere in the next four cycles. This means that this variation is
a long term property of the entire solar dynamo mechanism, both the toroidal
and poloidal fields, that hints at an unidentified component of the process
responsible for the long term memory.


title:
Assessing the habitability of planets with Earth-like atmospheres with
  1D and 3D climate modeling

abstract:
  The habitable zone (HZ) describes the range of orbital distances around a
star where the existence of liquid water on the surface of an Earth-like planet
is in principle possible. While 3D climate studies can calculate the water
vapor, ice albedo, and cloud feedback self-consistently and therefore allow for
a deeper understanding and the identification of relevant climate processes, 1D
model studies rely on fewer model assumptions and can be more easily applied to
the large parameter space possible for exoplanets. We evaluate the
applicability of 1D climate models to estimate the potential habitability of
Earth-like exoplanets by comparing our 1D model results to those of 3D climate
studies in the literature. We applied a cloud-free 1D radiative-convective
climate model to calculate the climate of Earth-like planets around different
types of main-sequence stars with varying surface albedo and relative humidity
profile. These parameters depend on climate feedbacks that are not treated
self-consistently in most 1D models. We compared the results to those of 3D
model calculations in the literature and investigated to what extent the 1D
model can approximate the surface temperatures calculated by the 3D models. The
1D parameter study results in a large range of climates possible for an
Earth-sized planet with an Earth-like atmosphere and water reservoir at a
certain stellar insolation. At some stellar insolations the full spectrum of
climate states could be realized, i.e., uninhabitable conditions as well as
habitable surface conditions, depending only on the relative humidity and
surface albedo assumed. When treating the surface albedo and the relative
humidity profile as parameters in 1D model studies and using the habitability
constraints found by recent 3D modeling studies, the same conclusions about the
potential habitability of a planet can be drawn as from 3D model calculations.


title:
A Local and Discrete Model Simulating Nonrelativistic Quantum Mechanical
  Systems

abstract:
  This paper presents a simple model that mimics quantum mechanics (QM) results
without using complex wavefunctions or non-localities. The proposed model only
uses integer-valued quantities and arithmetic operations, in particular
assuming a discrete spacetime under the form of a Euclidean lattice. The
proposed approach describes individual particle trajectories as random walks.
Transition probabilities are simple functions of a few quantities that are
either randomly associated to the particles during their preparation, or stored
in the lattice nodes they visit during the walk. Non-relativistic QM
predictions are retrieved as probability distributions of similarly-prepared
ensembles of particles. The scenarios considered to assess the model comprise
of free particle, constant external force, harmonic oscillator, particle in a
box, and the Delta potential.


title: Stochastic Variance Reduced Riemannian Eigensolver

abstract:
  We study the stochastic Riemannian gradient algorithm for matrix
eigen-decomposition. The state-of-the-art stochastic Riemannian algorithm
requires the learning rate to decay to zero and thus suffers from slow
convergence and sub-optimal solutions. In this paper, we address this issue by
deploying the variance reduction (VR) technique of stochastic gradient descent
(SGD). The technique was originally developed to solve convex problems in the
Euclidean space. We generalize it to Riemannian manifolds and realize it to
solve the non-convex eigen-decomposition problem. We are the first to propose
and analyze the generalization of SVRG to Riemannian manifolds. Specifically,
we propose the general variance reduction form, SVRRG, in the framework of the
stochastic Riemannian gradient optimization. It's then specialized to the
problem with eigensolvers and induces the SVRRG-EIGS algorithm. We provide a
novel and elegant theoretical analysis on this algorithm. The theory shows that
a fixed learning rate can be used in the Riemannian setting with an exponential
global convergence rate guaranteed. The theoretical results make a significant
improvement over existing studies, with the effectiveness empirically verified.


title:
Quasiharmonic Lattice Dynamics Calculations of Energy Balances in the
  Thermal Expansion of ULE Glass

abstract:
  Quasiharmonic lattice dynamics calculations are carried out on SiO2-TiO2
glass mixtures (TiO2 less than or equal to 20 weight percent) showing that the
addition of TiO2 systematically lowers the thermal expansion of high purity
fused silica. Adding ten weight percent titania lowers the thermal expansion
coefficient by approximately 0.5 ppm/K in agreement with observations. The
driving force for lowering the thermal expansion coefficient in the model
system is broken down into mode-by-mode contributions. The driving force is
distributed broadly across the frequency spectrum and is not localized into
particular frequency ranges that can be associated with the coordination
structure of Ti4+ in the simulated glass.


title:
Large-Signal Model of Graphene Field-Effect Transistors -- Part I:
  Compact Modeling of GFET Intrinsic Capacitances

abstract:
  We present a circuit-compatible compact model of the intrinsic capacitances
of graphene field-effect transistors (GFETs). Together with a compact drain
current model, a large-signal model of GFETs is developed combining both models
as a tool for simulating the electrical behavior of graphene-based integrated
circuits, dealing with the DC, transient behavior, and frequency response of
the circuit. The drain current model is based in a drift-diffusion mechanism
for the carrier transport coupled with an appropriate field-effect approach.
The intrinsic capacitance model consists of a 16-capacitance matrix including
self-capacitances and transcapacitances of a four-terminal GFET. To guarantee
charge conservation, a Ward-Dutton linear charge partition scheme has been
used. The large-signal model has been implemented in Verilog-A, being
compatible with conventional circuit simulators and serving as a starting point
toward the complete GFET device model that could incorporate additional
non-idealities.


title: Quaternionic Wiener Algebras, Factorization and Applications

abstract:
  We define an almost periodic extension of the Wiener algebras in the
quaternionic setting and prove a Wiener-Levy type theorem for it, as well as
extending the theorem to the matrix-valued case. We prove a Wiener-Hopf
factorization theorem for the quaternionic matrix-valued Wiener algebras
(discrete and continuous) and explore the connection to the Riemann-Hilbert
problem in that setting. As applications, we characterize solvability of two
classes of quaternionic functional equations and give an explicit formula for
the canonical factorization of quaternionic rational matrix functions via
realization.


title:
Large-Signal Model of Graphene Field-Effect Transistors -- Part II:
  Circuit Performance Benchmarking

abstract:
  This paper presents a circuit performance benchmarking using the large-signal
model of graphene field effect transistor reported in Part I of this two-part
paper. To test the model, it has been implemented in a circuit simulator.
Specifically we have simulated a high-frequency performance amplifier, together
with other circuits that take advantage of the ambipolarity of graphene, such
as a frequency doubler, a radio-frequency subharmonic mixer and a multiplier
phase detector. A variety of simulations comprising DC, transient dynamics,
Bode diagram, S-parameters, and power spectrum have been compared with
experimental data to assess the validity of the model.


title: LOTUS: A low cost, ultraviolet spectrograph

abstract:
  We describe the design, construction and commissioning of LOTUS; a simple,
low-cost long-slit spectrograph for the Liverpool Telescope. The design is
optimized for near-UV and visible wavelengths and uses all transmitting optics.
It exploits the instrument focal plane field curvature to partially correct
axial chromatic aberration. A stepped slit provides narrow (2.5x95 arcsec) and
wide (5x25 arcsec) options that are optimized for spectral resolution and flux
calibration respectively. On sky testing shows a wavelength range of 3200-6300
Angstroms with a peak system throughput (including detector quantum efficiency)
of 15 per cent and wavelength dependant spectral resolution of R=225-430. By
repeated observations of the symbiotic emission line star AG Peg we demonstrate
the wavelength stability of the system is less than 2 Angstroms rms and is
limited by the positioning of the object in the slit. The spectrograph is now
in routine operation monitoring the activity of comet 67P/Churyumov-Gerasimenko
during its current post-perihelion apparition.


title: The interaction between transpolar arcs and cusp spots

abstract:
  Transpolar arcs and cusp spots are both auroral phenomena which occur when
the interplanetary magnetic field is northward. Transpolar arcs are associated
with magnetic reconnection in the magnetotail, which closes magnetic flux and
results in a "wedge" of closed flux which remains trapped, embedded in the
magnetotail lobe. The cusp spot is an indicator of lobe reconnection at the
high-latitude magnetopause; in its simplest case, lobe reconnection
redistributes open flux without resulting in any net change in the open flux
content of the magnetosphere. We present observations of the two phenomena
interacting--i.e., a transpolar arc intersecting a cusp spot during part of its
lifetime. The significance of this observation is that lobe reconnection can
have the effect of opening closed magnetotail flux. We argue that such events
should not be rare.


title:
Search for optimal conditions for exploring double-parton scattering in
  four-jet production: $k_t$-factorization approach

abstract:
  In the present paper we discuss how to maximize the double-parton scattering
(DPS) contribution in four-jet production by selecting kinematical cuts. Here
both single-parton and double-parton scattering effects are calculated in the
$k_T$-factorization approach, following our recent developments of relevant
methods and tools. Several differential distributions are shown and discussed
in the context of future searches for DPS effects, such as rapidity of jets,
rapidity distance, and azimuthal correlations between jets. The dependences of
the relative DPS amount is studied as function of those observables. The
regions with an enhanced DPS contribution are identified. Future experimental
explorations could extract more precise values of $\sigma_{eff}$ and its
potential dependence on kinematical variables.


title: Optimal information diffusion in stochastic block models

abstract:
  We use the linear threshold model to study the diffusion of information on a
network generated by the stochastic block model. We focus our analysis on a two
community structure where the initial set of informed nodes lies only in one of
the two communities and we look for optimal network structures, i.e. those
maximizing the asymptotic extent of the diffusion. We find that, constraining
the mean degree and the fraction of initially informed nodes, the optimal
structure can be assortative (modular), core-periphery, or even disassortative.
We then look for minimal cost structures, i.e. those such that a minimal
fraction of initially informed nodes is needed to trigger a global cascade. We
find that the optimal networks are assortative but with a structure very close
to a core-periphery graph, i.e. a very dense community linked to a much more
sparsely connected periphery.


title:
Neighborhood Sensitive Mapping for Zero-Shot Classification using
  Independently Learned Semantic Embeddings

abstract:
  In a traditional setting, classifiers are trained to approximate a target
function $f:X \rightarrow Y$ where at least a sample for each $y \in Y$ is
presented to the training algorithm. In a zero-shot setting we have a subset of
the labels $\hat{Y} \subset Y$ for which we do not observe any corresponding
training instance. Still, the function $f$ that we train must be able to
correctly assign labels also on $\hat{Y}$. In practice, zero-shot problems are
very important especially when the label set is large and the cost of
editorially label samples for all possible values in the label set might be
prohibitively high. Most recent approaches to zero-shot learning are based on
finding and exploiting relationships between labels using semantic embeddings.
We show in this paper that semantic embeddings, despite being very good at
capturing relationships between labels, are not very good at capturing the
relationships among labels in a data-dependent manner. For this reason, we
propose a novel two-step process for learning a zero-shot classifier. In the
first step, we learn what we call a \emph{property embedding space} capturing
the "\emph{learnable}" features of the label set. Then, we exploit the learned
properties in order to reduce the generalization error for a linear nearest
neighbor-based classifier.


title: K-method of cognitive mapping analysis

abstract:
  Introduced a new calculation method (K-method) for cognitive maps. K - method
consists of two consecutive steps. In the first stage, allocated subgraph
composed of all paths from one selected node (concept) to another node
(concept) from the cognitive map (directed weighted graph) . In the second
stage, after the transition to an undirected graph (symmetrization adjacency
matrix) the influence of one node to another calculated with Kirchhoff method.
In the proposed method, there is no problem inherent in the impulse method. In
addition to "pair" influence of one node to another, the average
characteristics are introduced, allowing to calculate the impact of the
selected node to all other nodes and the influence of all on the one selected.
For impulse method similar to the average characteristics in the case where the
pulse method "works" are introduced and compared with the K-method.


title:
Profinite rigidity of graph manifolds and JSJ decompositions of
  3-manifolds

abstract:
  There has been much recent interest into those properties of a 3-manifold
determined by the profinite completion of its fundamental group. In this paper
we give readily computable criteria specifying precisely when two orientable
graph manifold groups have isomorphic profinite completions. Our results also
distinguish graph manifolds among the class of all 3-manifolds and give
information about the structure of totally hyperbolic manifolds, and give
control over the pro-$p$ completion of certain graph manifold groups.


title:
On the $p$-part of the Birch-Swinnerton-Dyer conjecture for elliptic
  curves with complex multiplication by the ring of integers of
  $\mathbb{Q}(\sqrt{-3})$

abstract:
  We study infinite families of quadratic and cubic twists of the elliptic
curve $E = X_0(27)$. For the family of quadratic twists, we establish a lower
bound for the $2$-adic valuation of the algebraic part of the value of the
complex $L$-series at $s=1$, and, for the family of cubic twists, we establish
a lower bound for the $3$-adic valuation of the algebraic part of the same
$L$-value. We show that our lower bounds are precisely those predicted by the
celebrated conjecture of Birch and Swinnerton-Dyer.


title:
The X-ray spectral evolution of the ultraluminous X-ray source Holmberg
  IX X-1

abstract:
  We present a new analysis of X-ray spectra of the archetypal ultraluminous
X-ray source (ULX) Holmberg IX X-1 obtained by the Swift, XMM-Newton and NuSTAR
observatories. This ULX is a persistent source, with a typical luminosity of
~10^40 erg s^-1, that varied by a factor of 4 - 5 over eight years. We find
that its spectra tend to evolve from relatively flat or two-component spectra
in the medium energy band (1-6 keV), at lower luminosities, to a spectrum that
is distinctly curved and disc-like at the highest luminosities, with the peak
energy in the curved spectrum tending to decrease with increased luminosity. We
argue that the spectral evolution of the ULX can be explained by
super-Eddington accretion models, where in this case we view the ULX down the
evacuated funnel along its rotation axis, bounded by its massive radiatively
driven wind. The spectral changes then originate in enhanced geometric beaming
as the accretion rate increases and wind funnel narrows, causing the scattered
flux from the central regions of the supercritical flow to brighten faster than
the isotropic thermal emission from the wind, and so the curved hard spectral
component to dominate at the highest luminosities. The wind also Compton
down-scatters photons at the edge of the funnel, resulting in the peak energy
of the spectrum decreasing. We also confirm that Holmberg IX X-1 displays
spectral degeneracy with luminosity, and suggest that the observed differences
are naturally explained by precession of the black hole rotation axis for the
suggested wind geometry.


title: cvpaper.challenge in 2015 - A review of CVPR2015 and DeepSurvey

abstract:
  The "cvpaper.challenge" is a group composed of members from AIST, Tokyo Denki
Univ. (TDU), and Univ. of Tsukuba that aims to systematically summarize papers
on computer vision, pattern recognition, and related fields. For this
particular review, we focused on reading the ALL 602 conference papers
presented at the CVPR2015, the premier annual computer vision event held in
June 2015, in order to grasp the trends in the field. Further, we are proposing
"DeepSurvey" as a mechanism embodying the entire process from the reading
through all the papers, the generation of ideas, and to the writing of paper.


title:
Regimes of radiative and nonradiative transitions in transport through
  an electronic system in a photon cavity reaching a steady state

abstract:
  We analyze how a multilevel many-electron system in a photon cavity
approaches the steady state when coupled to external leads. When a plunger gate
is used to lower cavity photon dressed one- and two-electron states below the
bias window defined by the external leads, we can identify one regime with
nonradiative transitions dominating the electron transport, and another regime
with radiative transitions. Both transitions trap the electrons in the states
below the bias bringing the system into a steady state. The order of the two
regimes and their relative strength depends on the location of the bias window
in the energy spectrum of the system and the initial conditions.


title:
The rationality of the moduli space of one-pointed ineffective spin
  hyperelliptic curves via an almost del Pezzo threefold

abstract:
  Using the geometry of an almost del Pezzo threefold, we show that the moduli
space of genus $g$ one-pointed ineffective spin hyperelliptic curves is
rational for every $g\geq 2$.


title:
2D radiaition-hydrodynamic simulations of supernova shock breakout in
  bipolar explosions of a blue supergiant progenitor

abstract:
  A two-dimensional special relativistic radiation-hydrodynamics code is
developed and applied to numerical simulations of supernova shock breakout in
bipolar explosions of a blue supergiant. Our calculations successfully simulate
the dynamical evolution of a blast wave in the star and its emergence from the
surface. Results of the model with spherical energy deposition show a good
agreement with previous simulations. Furthermore, we calculate several models
with bipolar energy deposition and compare their results with the spherically
symmetric model. The bolometric light curves of the shock breakout emission are
calculated by a ray-tracing method. Our radiation-hydrodynamic models indicate
that the early part of the shock breakout emission can be used to probe the
geometry of the blast wave produced as a result of the gravitational collapse
of the iron core.


title:
Photometry of Centaurs and trans-Neptunian objects: 2060 Chiron (1977
  UB), 10199 Chariklo (1997 CU26), 38628 Huya (2000 EB173), 28978 Ixion (2001
  KX76), and 90482 Orcus (2004 DW)

abstract:
  Both Centaurs and trans-Neptunian objects (TNOs) are minor bodies found in
the outer Solar System. Centaurs are a transient population that moves between
the orbits of Jupiter and Neptune, and they probably diffused out of the TNOs.
TNOs move mainly beyond Neptune. Some of these objects display episodic
cometary behaviour; a few percent of them are known to host binary companions.
Here, we study the light-curves of two Centaurs -2060 Chiron (1977 UB) and
10199 Chariklo (1997 CU26)- and three TNOs -38628 Huya (2000 EB173), 28978
Ixion (2001 KX76), and 90482 Orcus (2004 DW)- and the colours of the Centaurs
and Huya. Precise, ~1%, R-band absolute CCD photometry of these minor bodies
acquired between 2006 and 2011 is presented; the new data are used to
investigate the rotation rate of these objects. The colours of the Centaurs and
Huya are determined using BVRI photometry. The point spread function of the
five minor bodies is analysed, searching for signs of a coma or close
companions. Astrometry is also discussed. A periodogram analysis of the
light-curves of these objects gives the following rotational periods: 5.5+-0.4
h for Chiron, 7.0+-0.6 h for Chariklo, 4.45+-0.07 h for Huya, 12.4+-0.3 h for
Ixion, and 11.9+-0.5 h for Orcus. The colour indices of Chiron are found to be
B-V=0.53+-0.05, V-R=0.37+-0.08, and R-I=0.36+-0.15. The values computed for
Chariklo are V-R=0.62+-0.07 and R-I=0.61+-0.07. For Huya, we find
V-R=0.58+-0.09 and R-I=0.64+-0.20. We find very low levels of cometary activity
(if any) and no sign of close or wide binary companions for these minor bodies.


title:
Design of ternary alkaline-earth metal Sn(II) oxides with potential good
  p-type conductivity

abstract:
  Oxides with good p-type conductivity have been long sought after to achieve
high performance all-oxide optoelectronic devices. Divalent Sn(II) based oxides
are promising candidates because of their rather dispersive upper valence bands
caused by the Sn-5s/O-2p anti-bonding hybridization. There are so far few known
Sn(II) oxides being p-type conductive suitable for device applications. Here,
we present via first-principles global optimization structure searches a
material design study for a hitherto unexplored Sn(II)-based system, ternary
alkaline-earth metal Sn(II) oxides in the stoichiometry of MSn2O3 (M = Mg, Ca,
Sr, Ba). We identify two stable compounds of SrSn2O3 and BaSn2O3, which can be
stabilized by Sn-rich conditions in phase stability diagrams. Their structures
follow the Zintl behaviour and consist of basic structural motifs of SnO3
tetrahedra. Unexpectedly they show distinct electronic properties with band
gaps ranging from 1.90 (BaSn2O3) to 3.15 (SrSn2O3) eV, and hole effective
masses ranging from 0.87 (BaSn2O3) to above 6.0 (SrSn2O3) m0. Further
exploration of metastable phases indicates a wide tunability of electronic
properties controlled by the details of the bonding between the basic
structural motifs. This suggests further exploration of alkaline-earth metal
Sn(II) oxides for potential applications requiring good p-type conductivity
such as transparent conductors and photovoltaic absorbers.


title:
Electronic structure of Na, K, Si, and LiF from self-consistent solution
  of Hedin's equations including vertex corrections

abstract:
  A few self-consistent schemes to solve the Hedin equations are presented.
They include vertex corrections of different complexity. Commonly used
quasiparticle approximation for the Green function and static approximation for
the screened interaction are avoided altogether. Using alkali metals Na and K
as well as semiconductor Si and wide gap insulator LiF as examples, it is shown
that both the vertex corrections in the polarizability P and in the self energy
$\Sigma$ are important. Particularly, vertex corrections in $\Sigma$ with
proper treatment of frequency dependence of the screened interaction always
reduce calculated band widths/gaps, improving the agreement with experiment.
The complexity of the vertex included in P and in $\Sigma$ can be different.
Whereas in the case of polarizability one generally has to solve the
Bethe-Salpeter equation for the corresponding vertex function, it is enough
(for the materials in this study) to include the vertex of the first order in
the self energy. The calculations with appropriate vertices show remarkable
improvement in the calculated band widths and band gaps as compared to the
self-consistent GW approximation as well as to the self-consistent
quasiparticle GW approximation.


title: Robust Large Margin Deep Neural Networks

abstract:
  The generalization error of deep neural networks via their classification
margin is studied in this work. Our approach is based on the Jacobian matrix of
a deep neural network and can be applied to networks with arbitrary
non-linearities and pooling layers, and to networks with different
architectures such as feed forward networks and residual networks. Our analysis
leads to the conclusion that a bounded spectral norm of the network's Jacobian
matrix in the neighbourhood of the training samples is crucial for a deep
neural network of arbitrary depth and width to generalize well. This is a
significant improvement over the current bounds in the literature, which imply
that the generalization error grows with either the width or the depth of the
network. Moreover, it shows that the recently proposed batch normalization and
weight normalization re-parametrizations enjoy good generalization properties,
and leads to a novel network regularizer based on the network's Jacobian
matrix. The analysis is supported with experimental results on the MNIST,
CIFAR-10, LaRED and ImageNet datasets.


title:
Surface hopping from the perspective of quantum-classical Liouville
  dynamics

abstract:
  Fewest-switches surface hopping is studied in the context of
quantum-classical Liouville dynamics. Both approaches are mixed
quantum-classical theories that provide a way to describe and simulate the
nonadiabatic quantum dynamics of many-body systems. Starting from a
surface-hopping solution of the quantum-classical Liouville equation, it is
shown how fewest-switches dynamics can be obtained by dropping terms that are
responsible for decoherence and restricting the nuclear momentum changes that
accompany electronic transitions to those events that occur between population
states. The analysis provides information on some of the elements that are
essential for the construction of accurate and computationally tractable
algorithms for nonadiabatic processes.


title: Reweighting Parton Showers

abstract:
  We report on the possibility of reweighting parton-shower Monte Carlo
predictions for scale variations in the parton-shower algorithm. The method is
based on a generalization of the Sudakov veto algorithm. We demonstrate the
feasibility of this approach using example physical distributions.
Implementations are available for both the parton-shower modules in the Herwig
7 event generator.


title:
Low-rank tensor completion: a Riemannian manifold preconditioning
  approach

abstract:
  We propose a novel Riemannian manifold preconditioning approach for the
tensor completion problem with rank constraint. A novel Riemannian metric or
inner product is proposed that exploits the least-squares structure of the cost
function and takes into account the structured symmetry that exists in Tucker
decomposition. The specific metric allows to use the versatile framework of
Riemannian optimization on quotient manifolds to develop preconditioned
nonlinear conjugate gradient and stochastic gradient descent algorithms for
batch and online setups, respectively. Concrete matrix representations of
various optimization-related ingredients are listed. Numerical comparisons
suggest that our proposed algorithms robustly outperform state-of-the-art
algorithms across different synthetic and real-world datasets.


title: Pattern formation in a pseudo-parabolic equation

abstract:
  We address the propagation into an unstable state of a localised disturbance
in a forward-backward diffusion pseudo-parabolic equation. Three asymptotic
regimes are distinguished as t tends to infinity, the first being a regime
ahead of the propagating disturbance that is dominated by the linearised
equation. The analysis of this leads to the determination of the speed of the
leading edge of the propagating disturbance and implies that in the second,
transition, regime the solution takes the form of a modulated travelling wave.
In a third regime the solution approaches a nearly periodic steady state, where
the period is obtained on matching with the modulated travelling wave. Detailed
analysis of this pattern is also presented. The analysis is completed by
contrasting the formal asymptotic description of the solution with numerical
computations. It is assumed for the above analysis that the initial disturbance
decays faster than an exponential rate; in this case a critical exponential
decay rate at the leading edge of the front and propagation speed are found. We
investigate the wave speed selection mechanism for exponentially decaying
initial conditions. It is found that whenever the initial data behave as a real
exponential (no matter how slow the rate of the decay) the speed selected is
that selected by fast decaying initial conditions. However, for initial
conditions with a complex exponential we find regimes of the decay rate and the
wavelength for which the front propagates at a faster wave speed. This is
investigated numerically and is worth emphasising since it gives a different
scenario for wave speed behaviour than that exhibited by well-studied
semilinear reaction-diffusion equations: there are initial conditions with
exponential decay faster than the critical one for which the front propagates
with a speed faster than the critical one.


title: Minimum relative entropy distributions with a large mean are Gaussian

abstract:
  We consider the following frustrated optimization problem: given a prior
probability distribution $q$, find the distribution $p$ minimizing the relative
entropy with respect to $q$ such that $\textrm{mean}(p)$ is fixed and large. We
show that solutions to this problem are asymptotically Gaussian. As an
application we derive an $H$-type theorem for evolutionary dynamics: the
entropy of the (standardized) distribution of fitness of a population evolving
under natural selection is eventually increasing.

categories: cond-mat.stat-mech math.PR math.ST q-bio.PE stat.TH


title: A density problem for Sobolev spaces on Gromov hyperbolic domains

abstract:
  We prove that for a bounded domain $\Omega\subset \mathbb R^n$ which is
Gromov hyperbolic with respect to the quasihyperbolic metric, especially when
$\Omega$ is a finitely connected planar domain, the Sobolev space
$W^{1,\,\infty}(\Omega)$ is dense in $W^{1,\,p}(\Omega)$ for any $1\le
p<\infty$. Moreover if $\Omega$ is also Jordan or quasiconvex, then
$C^{\infty}(\mathbb R^n)$ is dense in $W^{1,\,p}(\Omega)$ for $1\le p<\infty$.


title:
The Importance of Worker Reputation Information in Microtask-Based Crowd
  Work Systems

abstract:
  This paper presents the first systematic investigation of the potential
performance gains for crowd work systems, deriving from available information
at the requester about individual worker reputation. In particular, we first
formalize the optimal task assignment problem when workers' reputation
estimates are available, as the maximization of a monotone (submodular)
function subject to Matroid constraints. Then, being the optimal problem
NP-hard, we propose a simple but efficient greedy heuristic task allocation
algorithm. We also propose a simple "maximum a-posteriori" decision rule and a
decision algorithm based on message passing. Finally, we test and compare
different solutions, showing that system performance can greatly benefit from
information about workers' reputation. Our main findings are that: i) even
largely inaccurate estimates of workers' reputation can be effectively
exploited in the task assignment to greatly improve system performance; ii) the
performance of the maximum a-posteriori decision rule quickly degrades as
worker reputation estimates become inaccurate; iii) when workers' reputation
estimates are significantly inaccurate, the best performance can be obtained by
combining our proposed task assignment algorithm with the message-passing
decision algorithm.


title: Competing structures in two dimensions: square-to-hexagonal transition

abstract:
  We study a system of particles in two dimensions interacting via a dipolar
long-range potential $D/r^3$ and subject to a square-lattice substrate
potential $V({\bf r})$ with amplitude $V$ and lattice constant $b$. The
isotropic interaction favors a hexagonal arrangement of the particles with
lattice constant $a$, which competes against the square symmetry of the
substrate lattice. We determine the minimal-energy states at fixed external
pressure $p$ generating the commensurate density $n = 1/b^2 = (4/3)^{1/2}/a^2$
in the absence of thermal and quantum fluctuations, using both analytical and
numerical techniques. At large substrate amplitude $V > 0.2\, e_D$, with $e_D =
D/b^3$ the dipolar energy scale, the particles reside in the substrate minima
and hence arrange in a square lattice. Upon decreasing $V$, the square lattice
turns unstable with respect to a zone-boundary shear-mode and deforms into a
period-doubled zig-zag lattice. Analytic and numerical results show that this
period-doubled phase in turn becomes unstable at $V \approx 0.074\, e_D$
towards a non-uniform phase developing an array of domain walls or solitons; as
the density of solitons increases, the particle arrangement approaches that of
a rhombic (or isosceles triangular) lattice. At a yet smaller substrate value
estimated as $V \approx 0.046\, e_D$, a further solitonic transition
establishes a second non-uniform phase which smoothly approaches the hexagonal
(or equilateral triangular) lattice phase with vanishing amplitude $V$. At
small but finite amplitude $V$, the hexagonal phase is distorted and
hexatically locked at an angle of $\varphi \approx 3.8^\circ$ with respect to
the substrate lattice. The square-to-hexagonal transformation in this
two-dimensional commensurate-incommensurate system thus involves a complex
pathway with various non-trivial lattice- and modulated phases.


title: Unification of Gravity and Electromagnetism and Cosmology

abstract:
  It is first argued that radiation by a uniformly accelerated charge in flat
space-time indicates the need for a unified geometric theory of gravity and
electromagnetism. Such a theory, based on a metric-affine $U_4$ manifold, is
constructed with the torsion pseudo-vector $\Gamma_\mu$ linking gravity and
electromagnetism. This conceptually simple extension results in (i) Einstein's
equations being modified by a vacuum energy $\Gamma_\mu\Gamma_\nu$ and a scalar
field $\Gamma = \Gamma^\mu\Gamma_\mu$ whose zero-mode is a cosmological
constant $\Lambda$ representing `dark energy', (ii) most of the salient
features of `dark matter'-like phenomena, (iii) a modified electrodynamics
satisfying Heaviside duality, (iv) a finite and small Casimir Effect, and at
the same time, (v) the empirical Schuster-Blackett-Wilson relation for the
amazingly universal gyromagnetic ratio of slowly rotating, neutral
astrophysical bodies.


title:
An Array of Layers in Silicon Sulfides: Chain-like and Ground State
  Structures

abstract:
  While much is known about isoelectronic materials related to carbon
nanostructures, such as boron nitride layers and nanotubes, rather less is
known about equivalent silicon based materials. Following the recent discovery
of phosphorene, we herein discuss isoelectronic silicon monosulfide monolayers.
We describe a set of anisotropic ground state structures that clearly have a
high stability with respect to the near isotropic silicon monosulfide
monolayers. The source of the layer anisotropy is related to the presence of
Si-S double chains linked by some Si-Si covalent bonds, which lye at the core
of the increased stability, together with a remarkable spd hybridization on Si.
The involvement of d orbitals brings more variety to silicon-sulfide based
nanostructures that are isoelectronic to phosphorene, which could be relevant
for future applications, adding extra degrees of freedom.


title:
The Effect of the Infrared Phase of the Discrete BFKL Pomeron on
  Transverse Momentum Diffusion

abstract:
  Imposing infrared boundary conditions on the BFKL equation with running
coupling transforms the complex momentum w-plane cut present in the gluon Green
function into an infinite series of positive Regge poles. In addition, a cut on
the negative w line remains. We consider a Hermitian kernel at leading order
with running coupling and construct the gluon Green function performing the w
integration away from the real axis. We find a strong dependence of the
asymptotic intercepts and collinear behaviour on the non-perturbative choice of
the boundary conditions, in the form of an infrared phase. This is particularly
manifest in the asymmetric infrared/ultraviolet structure of the associated
diffusion in transverse momentum. We find that random walks into the infrared
region are largely reduced in this approach.


title: A CFSG-free analysis of Babai's quasipolynomial GI-algorithm

abstract:
  We obtain a weaker but still quasipolynomial version of Babai's famous
GI-algorithm.


title: Radiative accidental matter

abstract:
  Accidental matter models are scenarios where the beyond-the-standard model
physics preserves all the standard model accidental and approximate symmetries
up to a cutoff scale related with lepton number violation. We study such
scenarios assuming that the new physics plays an active role in neutrino mass
generation, and show that this unavoidably leads to radiatively induced
neutrino masses. We systematically classify all possible models and determine
their viability by studying electroweak precision data, big bang
nucleosynthesis and electroweak perturbativity, finding that the latter places
the most stringent constraints on the mass spectra. These results allow the
identification of minimal radiative accidental matter models for which
perturbativity is lost at high scales. We calculate radiative charged-lepton
flavor violating processes in these setups, and show that $\mu\to e \gamma$ has
a rate well within MEG sensitivity provided the lepton-number violating scale
is at or below $10^6$ GeV, a value (naturally) assured by the radiative
suppression mechanism. Sizeable $\tau\to \mu \gamma$ branching fractions within
SuperKEKB sensitivity are possible for lower lepton-number breaking scales. We
thus point out that these scenarios can be tested not only in direct searches
but also in lepton-flavor violating experiments.


title: Negative Energy: From Lamb Shift to Entanglement

abstract:
  "Negative energy" has been one of the most enduring puzzles in quantum
theory, whereas the present work reveals that it actually plays a central role
in clarifying various controversies of quantum theory. The basic idea is
contained in a hypothesis on negative energy, and it is shown that the idea:
(1)is compatible with both relativistic quantum mechanics and known
experimental results; (2)helps to clarify the essence of matter waves, and
therefore better understand the reality of the wave function, the so-called
'wave-packet reduction' occurring in quantum measurement, and the ghost like
correlations between entangled systems; (3)is helpful for distinguishing the
vacuum from the ground state of the quantized field, and may supply a possible
way for removing the deep-rooted infinities in quantum field theory. The vacuum
energy density of the electromagnetic field is calculated here as an example.
By employing the same idea, the Lamb-Shift is recalculated in a different way
from conventional renormalization method, yet the same result as Bethe's can be
definitely obtained.


title: A Particle Model of Our Spacetime: Origin of Gravity

abstract:
  We build a model of our spacetime by assuming new particles called "space
quanta." In the ambient or bulk spacetime ${\cal S}^{D_{\rm amb}}$ ($D_{\rm
amb} \ge 4$), a multitude of space quanta form a nearly three-dimensional
object, whose continuum approximation is called the space 3-brane. The world
volume ${\cal WV}_{\rm sq}$ of this space 3-brane is described by an embedding
$f^A(x^\mu) \in {\cal S}^{D_{\rm amb}}$, which produces the induced metric
$\gamma_{\mu \nu}$ on the world volume ${\cal WV}_{\rm sq}$. This emergent
spacetime (${\cal WV}_{\rm sq}, \gamma_{\mu \nu}$) from the many space quanta
is proposed as the particle model of our spacetime. To study our spacetime
(${\cal WV}_{\rm sq}, \gamma_{\mu \nu}$), we construct what we call the
Aim-At-Target (AAT) method, which introduces an action for a 4D metric $g_{\mu
\nu}$. This metric action from the AAT method can lead to General Relativity at
low enough energies. The spacetime (${\cal S}_{\rm GR}, {\bf g}_{\mu \nu}$) of
General Relativity is, at least, a good approximation to the exact or true
spacetime (${\cal WV}_{\rm sq}, \gamma_{\mu \nu}$) of our universe.