title: On the Combination of Silent Error Detection and Checkpointing

abstract:
  In this paper, we revisit traditional checkpointing and rollback recovery
strategies, with a focus on silent data corruption errors. Contrarily to
fail-stop failures, such latent errors cannot be detected immediately, and a
mechanism to detect them must be provided. We consider two models: (i) errors
are detected after some delays following a probability distribution (typically,
an Exponential distribution); (ii) errors are detected through some
verification mechanism. In both cases, we compute the optimal period in order
to minimize the waste, i.e., the fraction of time where nodes do not perform
useful computations. In practice, only a fixed number of checkpoints can be
kept in memory, and the first model may lead to an irrecoverable failure. In
this case, we compute the minimum period required for an acceptable risk. For
the second model, there is no risk of irrecoverable failure, owing to the
verification mechanism, but the corresponding overhead is included in the
waste. Finally, both models are instantiated using realistic scenarios and
application/architecture parameters.


title: Information Loss and Anti-Aliasing Filters in Multirate Systems

abstract:
  This work investigates the information loss in a decimation system, i.e., in
a downsampler preceded by an anti-aliasing filter. It is shown that, without a
specific signal model in mind, the anti-aliasing filter cannot reduce
information loss, while, e.g., for a simple signal-plus-noise model it can. For
the Gaussian case, the optimal anti-aliasing filter is shown to coincide with
the one obtained from energetic considerations. For a non-Gaussian signal
corrupted by Gaussian noise, the Gaussian assumption yields an upper bound on
the information loss, justifying filter design principles based on second-order
statistics from an information-theoretic point-of-view.


title: How bosonic is a pair of fermions?

abstract:
  Composite particles made of two fermions can be treated as ideal elementary
bosons as long as the constituent fermions are sufficiently entangled. In that
case, the Pauli principle acting on the parts does not jeopardise the bosonic
behaviour of the whole. An indicator for bosonic quality is the composite boson
normalisation ratio $\chi_{N+1}/\chi_{N}$ of a state of $N$ composites. This
quantity is prohibitively complicated to compute exactly for realistic
two-fermion wavefunctions and large composite numbers $N$. Here, we provide an
efficient characterisation in terms of the purity $P$ and the largest
eigenvalue $\lambda_1$ of the reduced single-fermion state. We find the states
that extremise $\chi_N$ for given $P$ and $\lambda_1$, and we provide easily
evaluable, saturable upper and lower bounds for the normalisation ratio. Our
results strengthen the relationship between the bosonic quality of a composite
particle and the entanglement of its constituents.


title: Instant messaging an effective way of communication in workplace

abstract:
  The modern workplace is inherently collaborative, and this collaboration
relies on effective communication among coworkers. Instant messaging is the
multitasking tools of choice most people chatting over IM do other things at
the same time.The use of IM in workplace is less intrusive than the use of
phone, more immediate than email and has added advantage due to the ability to
detect presence.In order for institution to maximize increased business
productivity using instant messaging its imperative that organizations define
and publish ICT policies, guidelines and regulations.Overall IM boosts business
performance by making operations faster, more agile, and more efficient with
very little additional cost thus Organizations that deploy IM would reap
significant Return on Investment.Institutions should adopt IM meetings which
are be more efficient and less prone to straying off topic, because of the
relative effort of typing versus talking.


title:
Excitation of an Outflow From the Lower Solar Atmosphere and a
  Co-Temporal EUV Transient Brightening

abstract:
  We analyse an absorption event within the H$\alpha$ line wings, identified as
a surge, and the co-spatial evolution of an EUV brightening, with spatial and
temporal scales analogous to a small blinker. We conduct a multi-wavelength,
multi-instrument analysis using high-cadence, high-resolution data, collected
by the Interferometric BIdimensional Spectrometer on the Dunn Solar Telescope,
as well as the space-borne Atmospheric Imaging Assembly and Helioseismic and
Magnetic Imager instruments onboard the Solar Dynamics Observatory. One large
absorption event situated within the plage region trailing the lead sunspot of
AR 11579 is identified within the H-alpha line wings. This event is found to be
co-spatially linked to a medium-scale (around 4 arcseconds in diameter)
brightening within the transition region and corona. This ejection appears to
have a parabolic evolution, first forming in the H-alpha blue wing before
fading and reappearing in the H-alpha red wing, and comprises of a number of
smaller fibril events. The line-of-sight photospheric magnetic field shows no
evidence of cancellation leading to this event. Our research has identified
clear evidence that at least a subset of transient brightening events in the
transition region are linked to the influx of cooler plasma from the lower
solar atmosphere during large eruptive events, such as surges. These
observations agree with previous numerical researches on the nature of blinkers
and, therefore, suggest that magnetic reconnection is the driver of the
analysed surge events; however, further research is required to confirm this.


title: The connected components of the space of Alexandrov surfaces

abstract:
  Denote by $\mathcal{A}(\kappa)$ the set of all compact Alexandrov surfaces
with curvature bounded below by $\kappa$ without boundary, endowed with the
topology induced by the Gromov-Hausdorff metric. We determine the connected
components of $\mathcal{A}(\kappa)$ and of its closure.


title:
On existence and phase separation of solitary waves for nonlinear
  Schr\"odinger systems modelling simultaneous cooperation and competition

abstract:
  We study the existence of positive bound states for the nonlinear elliptic
system \[ \begin{cases} - \Delta u_i + \lambda_i u_i = \sum_{j=1}^d \beta_{ij}
u_j^2 u_i & \text{in $\Omega$} \\ u_1 =\cdots = u_d=0 & \text{on $\partial
\Omega$}, \end{cases} \] where $d \ge 2$, $\beta_{ij}= \beta_{ji}$,
$\beta_{ii},\lambda_i >0$, and $\Omega$ is either a bounded domain of
$\mathbb{R}^N$, or $\Omega=\mathbb{R}^N$, with $N \le 3$. In light of its
applicability in several physical contexts, the problem has been intensively
studied in recent years, and several results concerning existence, multiplicity
and qualitative properties of the solutions are available if either
$\beta_{ij}\le 0$ for every $i \neq j$, or $\beta_{ij}>0$ for every $i \neq j$
and some additional assumptions are satisfied. On the other hand, only very
partial results are known in the case of \emph{simultaneous cooperation and
competition}, that is, when there exist two pairs $(i_1,j_1)$ and $(i_2,j_2)$
such that $i_1 \neq j_1$, $i_2 \neq j_2$, $\beta_{i_1 j_1}>0$ and
$\beta_{i_2,j_2}<0$. In this setting, we provide sufficient conditions on the
coupling parameters $\beta_{ij}$ in order to have a positive solution. Our
first main results establishes the existence of solutions with at least $m$
positive components for every $m \le d$. Any such solution is a minimizer of
the energy functional $J$ restricted on a \emph{Nehari-type manifold}
$\mathcal{N}$. By means of level estimates on the constrained second
differential of $J$ on $\mathcal{N}$, we show that, under some additional
assumptions, any such minimizer has all nontrivial components. In order to
prove this second result, we analyse the phase separation phenomena which
involve solutions of the system in a \emph{not completely competitive}
framework.


title:
Functional Estimates for Derivatives of the Modified Bessel Function
  $K_{0}$ and related Exponential Functions

abstract:
  Let $K_{0}$ denote the modified Bessel function of second kind and zeroth
order. In this paper we will studying the function $\tilde{\omega}_{n}\left(
x\right) :=\frac{\left( -x\right) ^{n}K_{0}^{\left( n\right) }\left( x\right)
}{n!}$ for positive argument. The function $\tilde{\omega}_{n}$ plays an
important role for the formulation of the wave equation in two spatial
dimensions as a retarded potential integral equation. We will prove that the
growth of the derivatives $\tilde{\omega}_{n}^{\left( m\right) }$ with respect
to $n$ can be bounded by $O\left( \left( n+1\right) ^{m/2}\right) $ while for
small and large arguments $x$ the growth even becomes independent of $n$.
  These estimates are based on an integral representation of $K_{0}$ which
involves the function $g_{n}\left( t\right) =\frac{t^{n}}{n!}\exp\left(
-t\right) $ and their derivatives. The estimates then rely on a subtle analysis
of $g_{n}$ and its derivatives which we will also present in this paper.


title:
Using Cache-coloring to Mitigate Inter-set Write Variation in
  Non-volatile Caches

abstract:
  In recent years, researchers have explored use of non-volatile devices such
as STT-RAM (spin torque transfer RAM) for designing on-chip caches, since they
provide high density and consume low leakage power. A common limitation of all
non-volatile devices is their limited write endurance. Further, since existing
cache management policies are write-variation unaware, excessive writes to a
few blocks may lead to a quick failure of the whole cache. We propose an
architectural technique for wear-leveling of non-volatile last level caches
(LLCs). Our technique uses cache-coloring approach which adds a
software-controlled mapping layer between groups of physical pages and cache
sets. Periodically the mapping is altered to ensure that write-traffic can be
spread uniformly to different sets of the cache to achieve wear-leveling.
Simulations performed with an x86-64 simulator and SPEC2006 benchmarks show
that our technique reduces the worst-case writes to cache blocks and thus
improves the cache lifetime by 4.07X.


title: Structure Scalars In Charged Plane Symmetry

abstract:
  We consider non-adiabatic flow of the fluid possessing dissipation in the
form of shearing viscosity in electromagnetic field. The scalar functions
(structure scalars) for charged plane symmetry are formulated and are related
with the physical variables of the fluid. We also develop a relationship
between the Weyl tensor and other physical variables by using Taub mass
formalism. The role of electric charge as well as its physical significance for
the evolution of the shear tensor and expansion scalar are also explored.
Finally, we discuss a special case for dust with cosmological constant.


title: On the MHD modeling of the Crab Nebula radio emission

abstract:
  In recent years, it has become a well-established paradigm that many aspects
of the physics of Pulsar Wind Nebulae (PWNe) can be fully accounted for within
a relativistic MHD description. Numerical simulations have proven extremely
successful in reproducing the X-ray morphology of the Crab Nebula, down to very
fine detail. Radio emission, instead, is currently one of the most obscure
aspects of the physics of these objects, and one that holds important
information about pulsar properties and their role as antimatter factories.
Here we address the question of radio emission morphology and integrated
spectrum from the Crab Nebula, by using for the first time an axisymmetric
dynamical model with parameters chosen to best reproduce its X-ray morphology.
Based on our findings we discuss constraints on the origin of the radio
emitting particles.


title:
Counter-gradient heat transport in two-dimensional turbulent
  Rayleigh-B\'{e}nard convection

abstract:
  We present high-resolution numerical investigations of heat transport by
two-dimensional (2D) turbulent Rayleigh-B\'{e}nard (RB) convection over the
Rayleigh number range $10^8 \leqslant Ra\leqslant 10^{10}$ and the Prandtl
number range $0.7\leqslant Pr \leqslant10$. We find that there exist strong
counter-gradient local heat flux with magnitude much larger than the global
Nusselt number $Nu$ of the system. Two mechanisms for generating
counter-gradient heat transport are identified: one is due to the bulk dynamics
and the other is due to the competitions between the corner-flow rolls and the
large-scale circulation (LSC). While the magnitude of the former is found to
increase with increasing Prandtl number, that of the latter maximizes at medium
$Pr$. We further reveal that the corner-LSC competitions lead to the anomalous
$Nu$-$Pr$ relation in 2D RB convection, i.e. $Nu(Pr)$ minimizes, rather than
maximizes as in three-dimensional cylindrical case, at $Pr\approx2\sim3$ for
moderate $Ra$.


title:
Moments of the Gaussian $\beta$ Ensembles and the large-$N$ expansion of
  the densities

abstract:
  The loop equation formalism is used to compute the $1/N$ expansion of the
resolvent for the Gaussian $\beta$ ensemble up to and including the term at
$O(N^{-6})$. This allows the moments of the eigenvalue density to be computed
up to and including the 12-th power and the smoothed density to be expanded up
to and including the term at $O(N^{-6})$. The latter contain non-integrable
singularities at the endpoints of the support --- we show how to nonetheless
make sense of the average of a sufficiently smooth linear statistic. At the
special couplings $\beta = 1$, $2$ and $4$ there are characterisations of both
the resolvent and the moments which allows for the corresponding expansions to
be extended, in some recursive form at least, to arbitrary order. In this
regard we give fifth order linear differential equations for the density and
resolvent at $\beta = 1$ and $4$, which complements the known third order
linear differential equations for these quantities at $\beta = 2$.


title: Deep AutoRegressive Networks

abstract:
  We introduce a deep, generative autoencoder capable of learning hierarchies
of distributed representations from data. Successive deep stochastic hidden
layers are equipped with autoregressive connections, which enable the model to
be sampled from quickly and exactly via ancestral sampling. We derive an
efficient approximate parameter estimation method based on the minimum
description length (MDL) principle, which can be seen as maximising a
variational lower bound on the log-likelihood, with a feedforward neural
network implementing approximate inference. We demonstrate state-of-the-art
generative performance on a number of classic data sets: several UCI data sets,
MNIST and Atari 2600 games.


title:
Contemporaneous observations of the radio galaxy NGC 1275 from radio to
  very high energy gamma-rays

abstract:
  The radio galaxy NGC 1275, recently identified as a very high energy (VHE,
>100 GeV) gamma-ray emitter by MAGIC, is one of the few non-blazar AGN detected
in the VHE regime. In order to better understand the origin of the gamma-ray
emission and locate it within the galaxy, we studied contemporaneous
multi-frequency observations of NGC 1275 and modeled the overall spectral
energy distribution (SED). We analyzed unpublished MAGIC observations carried
out between Oct. 2009 and Feb. 2010, and the previously published ones taken
between Aug. 2010 and Feb. 2011. We studied the multi-band variability and
correlations by analyzing data of Fermi-LAT (0.1-100 GeV), as well as Chandra
(X-ray), KVA (optical) and MOJAVE (radio) data taken during the same period.
Using customized Monte Carlo simulations corresponding to early MAGIC stereo
data, we detect NGC 1275 also in the earlier campaign. The flux level and
energy spectra are similar to the results of the second campaign. The monthly
light curve >100 GeV shows a hint of variability at the 3.6 sigma level. In the
Fermi-LAT band, both flux and spectral shape variabilities are reported. The
optical light curve is variable and shows a clear correlation with the
gamma-ray flux >100 MeV. In radio, 3 compact components are resolved in the
innermost part of the jet. One of them shows a similar trend as the LAT and KVA
light curves. The 0.1-650 GeV spectra measured simultaneously with MAGIC and
Fermi-LAT can be well fitted either by a log-parabola or by a power-law with a
sub-exponential cutoff for both campaigns. A single-zone
synchrotron-self-Compton model, with an electron spectrum following a power-law
with an exponential cutoff, can explain the broadband SED and the multi-band
behavior of the source. However, this model suggests an untypical low
bulk-Lorentz factor or a velocity alignment closer to the line of sight than
the pc-scale radio jet.


title:
Pseudo-Casimir interactions across nematic films with disordered
  anchoring axis

abstract:
  We consider the effective pseudo-Casimir interaction forces mediated by a
nematic liquid-crystalline film bounded by two planar surfaces, one of which
imposes a random (disordered) distribution of the preferred anchoring axis in
the so-called easy direction. We consider both the case of a quenched as well
as an annealed disorder for the easy direction on the disordered surface and
analyze the resultant fluctuation-induced interaction between the surfaces. In
the case of quenched disorder, we show that the disorder effects appear
additively in the total interaction and are dominant at intermediate
inter-surface separations. Disorder effects are shown to be unimportant at both
very small and very large separations. In the case of annealed disorder its
effects are non-additive in the total inter-surface interaction and can be
rationalized in terms of a renormalized extrapolation length.


title:
A Fractional Power for Dunkl Transforms in $ L^{2}(\R^{N},
  \omega_{k}(x)dx)$

abstract:
  A new fractional version of the Dunkl transform for real order $\alpha$ is
obtained. An integral representation, a Bochner type identity and a Master
formula for this transform are derived.


title: Measurement of the $\tau$-lepton lifetime at Belle

abstract:
  The lifetime of the $\tau$-lepton is measured using the process
$e^+e^-\rightarrow\tau^+\tau^-$, where both $\tau$-leptons decay to
$3\pi\nu_\tau$. The result for the mean lifetime, based on
$711\,\mathrm{fb}^{-1}$ of data collected with the Belle detector at the
$\Upsilon(4S)$ resonance and $60\,\mathrm{MeV}$ below, is $\tau = (290.17 \pm
0.53(\mathrm{stat.}) \pm 0.33(\mathrm{syst.}))\cdot10^{-15}\,\mathrm{s}$. The
first measurement of the lifetime difference between $\tau^+$ and $\tau^-$ is
performed. The upper limit on the relative lifetime difference between positive
and negative $\tau$-leptons is $|\Delta\tau| / \tau < 7.0 \times 10^{-3}$ at
90% CL.


title: The addition and multiplication theorems

abstract:
  We discuss the classes $\fC$, $\fM$, and $\fS$ of analytic functions that can
be realized as the Liv\v{s}ic characteristic functions of a symmetric densely
defined operator $\dot A$ with deficiency indices $(1,1)$, the Weyl-Titchmarsh
functions associated with the pair $(\dot A, A)$ where $A$ is a self-adjoint
extension of $\dot A$, and the characteristic function of a maximal dissipative
extension $\widehat A$ of $\dot A$, respectively. We show that the class $\fM$
is a convex set, both of the classes $\fS$ and $\fC$ are closed under
multiplication and, moreover, $\fC\subset \fS$ is a double sided ideal in the
sense that $\fS\cdot \fC=\fC\cdot \fS\subset \fS$.
  The goal of this paper is to obtain these analytic results by providing
explicit constructions for the corresponding operator realizations.
  In particular, we introduce the concept of an operator coupling of two
unbounded maximal dissipative operators and establish an analog of the
Liv\v{s}ic-Potapov multiplication theorem [14] for the operators associated
with the function classes $\fC$ and $\fS$. We also establish that the modulus
of the von Neumann parameter characterizing the domain of $\widehat A$ is a
multiplicative functional with respect to the operator coupling.


title:
Minkowski decomposition and generators of the moving cone for toric
  varieties

abstract:
  We prove that for smooth projective toric varieties, the Okounkov body of a
$T$-invariant pseudo-effective divisor with respect to a $T$-invariant flag
decomposes as a finite Minkowski sum of indecomposable polytopes. We prove that
these indecomposable polytopes form a Minkowski base and that they correspond
to the rays in the secondary fan. Moreover, we present an algorithm to find the
Minkowski base.


title: Latitudinal Connectivity of Ground Level Enhancement Events

abstract:
  We examined the source regions and coronal environment of the historical
ground level enhancement (GLE) events in search of evidence for non-radial
motion of the associated coronal mass ejection (CME). For the 13 GLE events
that had source latitudes >30 degrees we found evidence for possible non-radial
CME motion due to deflection by large-scale magnetic structures in nearby
coronal holes, streamers, or pseudo streamers. Polar coronal holes are the main
source of deflection in the rise and declining phases of solar cycles. In the
maximum phase, deflection by large-scale streamers or pseudo streamers
overlying high-latitude filaments seems to be important. The B0 angle reduced
the ecliptic distance of some GLE source regions and increased in others with
the net result that the average latitude of GLE events did not change
significantly. The non-radial CME motion is the dominant factor that reduces
the ecliptic distance of GLE source regions, thereby improving the latitudinal
connectivity to Earth. We further infer that the GLE particles must be
accelerated at the nose part of the CME-driven shocks, where the shock is
likely to be quasi-parallel.


title:
Superconformal indices and partition functions for supersymmetric field
  theories

abstract:
  Recently there was a substantial progress in understanding of supersymmetric
theories (in particular, their BPS spectrum) in space-times of different
dimensions due to the exact computation of superconformal indices and partition
functions using localization method. Here we discuss a connection of 4d
superconformal indices and 3d partition functions using a particular example of
supersymmetric theories with matter in antisymmetric representation.


title:
The distorted mirror of Wikipedia: a quantitative analysis of Wikipedia
  coverage of academics

abstract:
  Activity of modern scholarship creates online footprints galore. Along with
traditional metrics of research quality, such as citation counts, online images
of researchers and institutions increasingly matter in evaluating academic
impact, decisions about grant allocation, and promotion. We examined 400
biographical Wikipedia articles on academics from four scientific fields to
test if being featured in the world's largest online encyclopedia is correlated
with higher academic notability (assessed through citation counts). We found no
statistically significant correlation between Wikipedia articles metrics
(length, number of edits, number of incoming links from other articles, etc.)
and academic notability of the mentioned researchers. We also did not find any
evidence that the scientists with better WP representation are necessarily more
prominent in their fields. In addition, we inspected the Wikipedia coverage of
notable scientists sampled from Thomson Reuters list of "highly cited
researchers". In each of the examined fields, Wikipedia failed in covering
notable scholars properly. Both findings imply that Wikipedia might be
producing an inaccurate image of academics on the front end of science. By
shedding light on how public perception of academic progress is formed, this
study alerts that a subjective element might have been introduced into the
hitherto structured system of academic evaluation.

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


title:
Construction of extremal or optimal codes with an automorphism of order
  29

abstract:
  In this paper we construct a new optimal code with parameters [120, 60, 20]
of type II with an automorphism of order 29. Furthermore we classify all
extremal codes with length 60 of type I with an automorphism of this order.


title: Testing the Empirical Shock Arrival Model using Quadrature Observations

abstract:
  The empirical shock arrival (ESA) model was developed based on quadrature
data from Helios (in-situ) and P-78 (remote-sensing) to predict the Sun-Earth
travel time of coronal mass ejections (CMEs) [Gopalswamy et al. 2005a]. The ESA
model requires earthward CME speed as input, which is not directly measurable
from coronagraphs along the Sun-Earth line. The Solar Terrestrial Relations
Observatory (STEREO) and the Solar and Heliospheric Observatory (SOHO) were in
quadrature during 2010 - 2012, so the speeds of Earth-directed CMEs were
observed with minimal projection effects. We identified a set of 20 full halo
CMEs in the field of view of SOHO that were also observed in quadrature by
STEREO. We used the earthward speed from STEREO measurements as input to the
ESA model and compared the resulting travel times with the observed ones from
L1 monitors. We find that the model predicts the CME travel time within about
7.3 hours, which is similar to the predictions by the ENLIL model. We also find
that CME-CME and CME-coronal hole interaction can lead to large deviations from
model predictions.


title:
A Preadapted Universal Switch Distribution for Testing Hilberg's
  Conjecture

abstract:
  Hilberg's conjecture about natural language states that the mutual
information between two adjacent long blocks of text grows like a power of the
block length. The exponent in this statement can be upper bounded using the
pointwise mutual information estimate computed for a carefully chosen code. The
bound is the better, the lower the compression rate is but there is a
requirement that the code be universal. So as to improve a received upper bound
for Hilberg's exponent, in this paper, we introduce two novel universal codes,
called the plain switch distribution and the preadapted switch distribution.
Generally speaking, switch distributions are certain mixtures of adaptive
Markov chains of varying orders with some additional communication to avoid so
called catch-up phenomenon. The advantage of these distributions is that they
both achieve a low compression rate and are guaranteed to be universal. Using
the switch distributions we obtain that a sample of a text in English is
non-Markovian with Hilberg's exponent being $\le 0.83$, which improves over the
previous bound $\le 0.94$ obtained using the Lempel-Ziv code.


title:
New symmetry reductions related with the residual symmetry of Boussinesq
  equation

abstract:
  The Backlund transformation related symmetry is nonlocal, which is hardly to
apply in constructing solutions for nonlinear equations. In this paper, we
first localize nonlocal residual symmetry to Lie point symmetry by introducing
multiple new variables and obtain new Baaklund transformation. Then, by solving
out the general form of localized the residual symmetry, we reduce the enlarged
system by classical symmetry approach and obtain the corresponding reduction
solutions as well as related reduction equations. The localization procedure
provides a new way to investigate interaction solutions between different
waves.


title:
Correspondence between classical and Dirac-Pauli spinors in view of the
  Foldy-Wouthuysen transformation

abstract:
  The classical dynamics for a charged spin particle is governed by the Lorentz
force equation for orbital motion and by the Thomas-Bargmann-Michel-Telegdi
(T-BMT) equation for spin precession. In static and homogeneous electromagnetic
fields, it has been shown that the Foldy-Wouthuysen (FW) transform of the
Dirac-Pauli Hamiltonian, which describes the relativistic quantum theory for a
spin-1/2 particle, is consistent with the classical Hamiltonian (with both the
orbital and spin parts) up to the order of $1/m^{14}$ ($m$ is the particle's
mass) in the low-energy/weak-field limit. In this paper, we extend this
correspondence to the case of inhomogeneous fields. Regardless of the field
gradient (e.g., Stern-Gerlach) force, the T-BMT equation is unaltered and thus
the classical Hamiltonian remains the same, but subtleties arise and need to be
clarified. For the relativistic quantum theory, we apply Eriksen's method to
obtain the exact FW transformations for the two special cases, which in
conjunction strongly suggest that, in the weak-field limit, the FW transformed
Dirac-Pauli Hamiltonian (except for the Darwin term) is in agreement with the
classical Hamiltonian in a manner that classical variables correspond to
quantum operators via a specific Weyl ordering. Meanwhile, the Darwin term is
shown to have no classical correspondence.


title: On The Real Part of a Conformal Field Theory

abstract:
  Every conformal field theory has the symmetry of taking each field to its
adjoint. We consider here the quotient (orbifold) conformal field theory
obtained by twisting with respect to this symmetry. A general method for
computing such quotients is developed using the coulomb gas representation.
Examples of parafermions, $SU(2)$ current algebra and the $N=2$ minimal models
are described explicitly. The partition functions and the dimensions of the
disordered fields are given. This result is a tool for finding new theories.


title:
Scheila's Scar: Direct Evidence of Impact Surface Alteration on a
  Primitive Asteroid

abstract:
  Asteroid (596) Scheila was the first object for which the immediate aftermath
of an inter-asteroidal collision was observed. In Dec. 2010, the 113 km-sized
asteroid was impacted by a smaller asteroid of less than 100 m in diameter. The
scale of the impactor was established by observations of fading ejecta plumes.
Comparison of the light curves obtained before and after the impact allowed us
to assess how much of Scheila's surface was altered. Cratering physics based on
the impactor size suggests that the size of the affected area is larger than
expected, (effective radii of 3.5 -- 10 km depending on the change in the
albedo of the surface). Similar but more localized albedo changes have been
observed on Vesta and the Martian moons, but are not understood. Empirical laws
describing ejecta blankets however indicate that at distances between 3.5 -- 10
km from the crater, Scheila's surface would be covered by a thin layer 2 mm to
2 cm thick. This dusting, possibly mixed with bright impactor material may be
enough to explain to observed brightness increase. Our results show that
sub-critical impacts may play a significant role in processing the surfaces of
asteroids. The large effect of small impacts on asteroidal light curves
complicate shape modeling.


title: Non-orientable surfaces in homology cobordisms

abstract:
  We investigate constraints on embeddings of a non-orientable surface in a
$4$-manifold with the homology of $M \times I$, where $M$ is a rational
homology $3$-sphere. The constraints take the form of inequalities involving
the genus and normal Euler class of the surface, and either the
Ozsv\'ath--Sazb\'o $d$-invariants or Atiyah--Singer $\rho$-invariants of $M$.
One consequence is that the minimal genus of a smoothly embedded surface in
$L(2p,q) \times I$ is the same as the minimal genus of a surface in $L(2p,q)$.
We also consider embeddings of non-orientable surfaces in closed $4$-manifolds.


title: Gap solitons in the spin-orbit coupled Bose-Einstein condensates

abstract:
  We report a diversity of stable gap solitons in a spin-orbit coupled
Bose-Einstein condensate subject to a spatially periodic Zeeman field. It is
shown that the solitons, can be classified by the main physical symmetries they
obey, i.e. symmetries with respect to parity (P), time (T), and internal degree
of freedom, i.e. spin, (C) inversions. The conventional gap and gap-stripe
solitons are obtained in lattices with different parameters. It is shown that
solitons of the same type but obeying different symmetries can exist in the
same lattice at different spatial locations. PT and CPT symmetric solitons have
anti-ferromagnetic structure and are characterized respectively by nonzero and
zero total magnetizations.


title: Dispersion estimates for 1D discrete equations

abstract:
  We derive the dispersion decay for solutions of the 1D discrete Schroedinger
and wave equations. Based on previous works, we weaken the conditions on
potentials.


title:
Estimations of the best approximations of classes of infinitely
  differentiable functions in uniform and integral metrics

abstract:
  We find uniform with respect to parameter $p \ (1\leq p\leq\infty)$ upper
estimations of best approximations by trigonometric polynomials of classes
$C^{\psi}_{\beta,p}$ of periodic functions generated by sequences $\psi(k)$,
that decrease to nought faster than any power function. Obtained estimations
are exact for order and have constants that are written in explicit form and
depend on function $\psi$ only. We obtain analogical estimations for best
approximations of classes $L^{\psi}_{\beta,1}$ in metrics of spaces $L_{s}$,
$1\leq s\leq \infty$.


title: High-frequency homogenisation for hexagonal and honeycomb lattices

abstract:
  A high-frequency asymptotic scheme is generated that captures the motion of
waves within discrete hexagonal and honeycomb lattices by creating continuum
homogenised equations. The accuracy of these effective medium equations in
describing the frequency-dependent anisotropy of the lattice structure is
demonstrated. We then extend the general formulation by introducing line
defects, often called armchair or zigzag line defects for honeycomb lattices
such as graphene, into an otherwise perfect lattice creating surface waves
which propagate in the direction of the defect and decay away from it. A
quasi-one-dimensional multiple scale method is outlined, which allows us to
derive Schroedinger equations describing the local oscillations near particular
frequencies in the Bloch spectrum. Further localization by single defects
embedded within the line defect are also considered.


title: Local Polyakov loop domains and their fractality

abstract:
  We discuss properties of local Polyakov loops in the deconfinement transition
of SU(3) lattice gauge theory at finite temperature using the fixed scale
approach. In particular we study spatial clusters where local Polyakov loops
have phases near the same center elements of the gauge group. We present
results for various properties of the center clusters, e.g., their percolation
probability or their fractality and discuss the physical implications for
temperatures below and above the phase transition.


title: Field reduction and linear sets in finite geometry

abstract:
  Based on the simple and well understood concept of subfields in a finite
field, the technique called `field reduction' has proved to be a very useful
and powerful tool in finite geometry. In this paper we elaborate on this
technique. Field reduction for projective and polar spaces is formalized and
the links with Desarguesian spreads and linear sets are explained in detail.
Recent results and some fundamental ques- tions about linear sets and scattered
spaces are studied. The relevance of field reduction is illustrated by
discussing applications to blocking sets and semifields.


title: Jackson's $(-1)$-Bessel functions with the Askey-Wilson algebra setting

abstract:
  The aim of this work is to study new functions arising from the limit
transition of the Jackson's $q$-Bessel functions when $q\rightarrow -1$. These
functions coincide with the $cas$ function for particular values of their
parameters. We prove also that these functions are eigenfunction of
differential-difference operators of Dunkl-type. Further, we consider special
cases of the Askey-Wilson algebra $AW(3)$ that have these operators (up to
constants) as one of their three generators and whose defining relations are
given in terms of anticommutators.


title:
Interaction-induced localization of mobile impurities in ultracold
  systems

abstract:
  The impurities, introduced intentionally or accidentally into certain
materials, can significantly modify their characteristics or reveal their
intrinsic physical properties, and thus play an important role in solid-state
physics. Different from those static impurities in a solid, the impurities
realized in cold atomic systems are naturally mobile. Here we propose an
effective theory for treating some unique behaviors exhibited by ultracold
mobile impurities. Our theory reveals the interaction-induced transition
between the extended and localized impurity states, and also explains the
essential features obtained from several previous models in a unified way.
Based on our theory, we predict many intriguing phenomena in ultracold systems
associated with the extended and localized impurities, including the formation
of the impurity-molecules and impurity-lattices. We hope this investigation can
open up a new avenue for the future studies on ultracold mobile impurities.


title: Massive Kaluza-Klein Gravity

abstract:
  The non-Abelian Kaluza-Klein unification of gravitation with gauge fields
theory is reformulated, with the inclusion of a massive spin-2 field defined by
the extrinsic curvature. The internal space is non-compact, characterized by
the group of rotations of vectors orthogonal to the space-time. The
non-compactness of the internal space warrants the solution of the fermion
chirality problem of the original Kaluza-Klein theory and makes it closer to
the more recent Brane World paradigm, in special to the so called DGP model.
However, the access of gravitation to the extra dimensions is defined by the
mentioned massive spin-2 field obeying the Fierz-Pauli equation. The existence
of a short range gravitational component makes possible to apply the modified
Kaluza-Klein unification to the Tev scale of energies.


title: Implicit vs Explicit renormalization of the $NN$ force

abstract:
  We use an S-wave toy model for the two-nucleon system to show that the
implicit renormalization of a contact theory matches the explicit
renormalization through a flow equation which integrates out the high momentum
components. By fitting the low-momentum interaction with a new contact theory,
we show that the running of the contact strengths in both original and fitted
contact theories match over a wide cutoff range.


title:
A water level relationship between consecutive gauge stations along
  Solim\~oes/Amazonas main channel: a wavelet approach

abstract:
  Gauge stations are distributed along the Solim\~oes/Amazonas main channel to
monitor water level changes over time. Those measurements help quantify both
the water movement and its variability from one gauge station to the next
downstream. The objective of this study is to detect changes in the water level
relationship between consecutive gauge stations along the Solim\~oes/Amazonas
main channel, since 1980. To carry out the analyses, data spanning from 1980 to
2010 from three consecutive gauges (Tefe, Manaus and Obidos) were used to
compute standardized daily anomalies. In particular for infra-annual periods it
was possible to detect changes for the water level variability along the
Solim\~oes/Amazonas main channel, by applying the Morlet Wavelet Transformation
(WT) and Wavelet Cross Coherence (WCC) methods. It was possible to quantify the
waves amplitude for the WT infra-annual scaled-period and were quite similar to
the three gauge stations denoting that the water level variability are related
to the same hydrological forcing functions. Changes in the WCC was detected for
the Manaus-Obidos river stretch and this characteristic might be associated
with land cover changes in the floodplains. The next steps of this research,
will be to test this hypotheses by integrating land cover changes into the
floodplain with hydrological modelling simulations throughout the time-series.


title:
A comparison of vakonomic and nonholonomic dynamics with applications to
  non-invariant Chaplygin systems

abstract:
  We study relations between vakonomically and nonholonomically constrained
Lagrangian dynamics for the same set of linear constraints. The basic idea is
to compare both situations at the level of variational principles, not
equations of motion as has been done so far. The method seems to be quite
powerful and effective. In particular, it allows to derive, interpret and
generalize many known results on non-Abelian Chaplygin systems. We apply it
also to a class of systems on Lie groups with a left-invariant constraints
distribution. Concrete examples of the unicycle in a potential field, the
two-wheeled carriage and the generalized Heisenberg system are discussed.


title:
Observation of quantum jumps of a single quantum dot spin using
  sub-microsecond single-shot optical readout

abstract:
  Single-shot read-out of individual qubits is typically the slowest process
among the elementary single- and two-qubit operations required for quantum
information processing. Here, we use resonance fluorescence from a
single-electron charged quantum dot to read-out the spin-qubit state in 800
nanoseconds with a fidelity exceeding 80%. Observation of the spin evolution on
longer timescales reveals quantum jumps of the spin state: we use the
experimentally determined waiting-time distribution to characterize the quantum
jumps. Embedding a quantum dot in a photonic nanostructure could be used to
enhance the collection efficiency by a factor of 10, enabling single-shot
read-out with a fidelity exceeding 97%.


title:
Peripheral NN scattering from subtractive renormalization of chiral
  interactions

abstract:
  We apply five subtractions in the Lippman-Schwinger (LS) equation in order to
perform a non-perturbative renormalization of chiral N3LO nucleon-nucleon
interactions. Here we compute the phase shifts for the uncoupled peripheral
waves at renormalization scales between $0.1~ \rm{fm}^{-1}$ and $1 ~
\rm{fm}^{-1}$. In this range, the results are scale invariant and provide an
overall goof agreement with the Nijmegen partial wave analysis up to at least
$E_{\rm{lab}} = 150 ~ \rm{MeV}$, with a cutoff at $\Lambda = 30~\rm{fm}^{-1}$.


title:
Local $Tb$ theorem with $L^2$ testing conditions and general measures:
  Calder\'on-Zygmund operators

abstract:
  Local $Tb$ theorems with $L^p$ type testing conditions, which are not scale
invariant, have been studied widely in the case of the Lebesgue measure. Until
very recently, local $Tb$ theorems in the non-homogeneous case had only been
proved assuming scale invariant ($L^{\infty}$ or BMO) testing conditions. The
combination of non-scale-invariance and general measures is a delicate issue.
In a previous paper we overcame this obstacle in the model case of square
functions defined using general measures. In this paper we finally tackle the
very demanding case of Calder\'on-Zygmund operators. That is, we prove a
non-homogeneous local $Tb$ theorem with $L^2$ type testing conditions for all
Calder\'on-Zygmund operators. In doing so we prove general twisted martingale
transform inequalities which turn out to be subtle in our general framework.


title:
On the Capacity of Multiple Access and Broadcast Fading Channels with
  Full Channel State Information at Low SNR

abstract:
  We study the throughput capacity region of the Gaussian multi-access (MAC)
fading channel with perfect channel state information (CSI) at the receiver and
at the transmitters, at low power regime. We show that it has a
multidimensional rectangle structure and thus is simply characterized by single
user capacity points. More specifically, we show that at low power regime, the
boundary surface of the capacity region shrinks to a single point corresponding
to the sum rate maximizer and that the coordinates of this point coincide with
single user capacity bounds. Inspired by this result, we propose an on-off
scheme, compute its achievable rate, and show that this scheme achieves single
user capacity bounds of the MAC channel for a wide class of fading channels at
asymptotically low power regime. We argue that this class of fading encompasses
all known wireless channels for which the capacity region of the MAC channel
has even a simpler expression in terms of users' average power constraints
only. Using the duality of Gaussian MAC and broadcast channels (BC), we deduce
a simple characterization of the BC capacity region at low power regime and
show that for a class of fading channels (including Rayleigh fading),
time-sharing is asymptotically optimal.


title:
A lower bound for the algebraic connectivity of a graph in terms of the
  domination number

abstract:
  We investigate how the algebraic connectivity of a graph changes by
relocating a connected branch from one vertex to another vertex, and then
minimize the algebraic connectivity among all connected graphs of order $n$
with fixed domination number $\gamma \le \frac{n+2}{3}$, and finally present a
lower bound for the algebraic connectivity in terms of the domination number.


title:
Energy evolution of the moments of the hadron distribution in QCD jets
  including NNLL resummation and NLO running-coupling corrections

abstract:
  The moments of the single inclusive momentum distribution of hadrons in QCD
jets, are studied in the next-to-modified-leading-log approximation (NMLLA)
including next-to-leading-order (NLO) corrections to the alpha_s strong
coupling. The evolution equations are solved using a distorted Gaussian
parametrisation, which successfully reproduces the spectrum of charged hadrons
of jets measured in e+e- collisions. The energy dependencies of the maximum
peak, multiplicity, width, kurtosis and skewness of the jet hadron distribution
are computed analytically. Comparisons of all the existing jet data measured in
e+e- collisions in the range sqrt(s)~2-200 GeV to the NMLLA+NLO* predictions
allow one to extract a value of the QCD parameter Lambda_QCD, and associated
two-loop coupling constant at the Z resonance alpha_s(m_Z^2)= 0.1195 +/-
0.0022, in excellent numerical agreement with the current world average
obtained using other methods.


title: Dual Methods for Lattice Field Theories at Finite Density

abstract:
  We present a dual representation of the partition function of the charged
scalar field in which the complex action problem at non-zero chemical potential
is absent. In this dual representation Monte Carlo simulations are possible and
we show some physical results obtained with this approach. Furthermore we
present a technique to study 2-point functions at finite density. Results for
the lattice correlators at various chemical potentials are shown and discussed.


title: Numerical Stochastic Perturbation Theory in the Schr\"odinger Functional

abstract:
  The Schr\"odinger functional (SF) is a powerful and widely used tool for the
treatment of a variety of problems in renormalization and related areas. Albeit
offering many conceptual advantages, one major downside of the SF scheme is the
fact that perturbative calculations quickly become cumbersome with the
inclusion of higher orders in the gauge coupling and hence the use of an
automated perturbation theory framework is desirable. We present the
implementation of the SF in numerical stochastic perturbation theory (NSPT) and
compare first results for the running coupling at two loops in pure SU(3)
Yang-Mills theory with the literature.


title: GL^+(2,R)-orbits in Prym eigenform loci

abstract:
  This paper is devoted to the classification of GL^+(2,R)-orbit closures of
surfaces in the intersection of the Prym eigenform locus with various strata of
quadratic differentials. We show that the following dichotomy holds: an orbit
is either closed or dense in a connected component of the Prym eigenform locus.
  The proof uses several topological properties of Prym eigenforms, which are
proved by the authors in a previous work. In particular the tools and the proof
are independent of the recent results of Eskin-Mirzakhani-Mohammadi.
  As an application we obtain a finiteness result for the number of closed
GL^+(2,R)-orbits (not necessarily primitive) in the Prym eigenform locus
Prym_D(2,2) for any fixed D that is not a square.


title: Symmetry Groups of Principal Bundles Over Non-Compact Bases

abstract:
  In this work, we describe how to obtain the structure of an
infinite-dimensional Lie group on the group of compactly carried bundle
automorphisms Autc(P) for a locally convex prinicpal bundle P over a
finite-dimensional smooth sigma-compact base M. This is a generalization of
previous work by Wockel, where the base M was compact. We first consider the
Lie group structure on the group of compactly carried vertical bundle morphisms
Gauc(P) (in both cases "compactly carried" refers to being compactly carried on
the base in a certain sense). We then introduce the Lie group structure on
Autc(P) as an extension of a certain open Lie subgroup of the compactly carried
diffeomorphisms Diffc(M) by the gauge group Gauc(P). We find an explicit
condition on P ensuring that Gauc(P) can be equipped with a Lie group structure
enabling the extension just mentioned and show that this condition is satisfied
by selected classes of bundles.


title: Temporal naturalism

abstract:
  Two people may claim both to be naturalists, but have divergent conceptions
of basic elements of the natural world which lead them to mean different things
when they talk about laws of nature, or states, or the role of mathematics in
physics. These disagreements do not much affect the ordinary practice of
science which is about small subsystems of the universe, described or explained
against a background, idealized to be fixed. But these issues become crucial
when we consider including the whole universe within our system, for then there
is no fixed background to reference observables to. I argue here that the key
issue responsible for divergent versions of naturalism and divergent approaches
to cosmology is the conception of time. One version, which I call temporal
naturalism, holds that time, in the sense of the succession of present moments,
is real, and that laws of nature evolve in that time. This is contrasted with
timeless naturalism, which holds that laws are immutable and the present moment
and its passage are illusions. I argue that temporal naturalism is empirically
more adequate than the alternatives, because it offers testable explanations
for puzzles its rivals cannot address, and is likely a better basis for solving
major puzzles that presently face cosmology and physics.
  This essay also addresses the problem of qualia and experience within
naturalism and argues that only temporal naturalism can make a place for qualia
as intrinsic qualities of matter.


title: Quantitative Assessment of TV White Space in India

abstract:
  Licensed but unutilized television (TV) band spectrum is called as TV white
space in the literature. Ultra high frequency (UHF) TV band spectrum has very
good wireless radio propagation characteristics. The amount of TV white space
in the UHF TV band in India is of interest. Comprehensive quantitative
assessment and estimates for the TV white space in the 470-590MHz band for four
zones of India (all except north) are presented in this work. This is the first
effort in India to estimate TV white spaces in a comprehensive manner. The
average available TV white space per unit area in these four zones is
calculated using two methods: (i) the primary (licensed) user and secondary
(unlicensed) user point of view; and, (ii) the regulations of Federal
Communications Commission in the United States. By both methods, the average
available TV white space in the UHF TV band is shown to be more than 100MHz! A
TV transmitter frequency-reassignment algorithm is also described. Based on
spatial-reuse ideas, a TV channel allocation scheme is presented which results
in insignicant interference to the TV receivers while using the least number of
TV channels for transmission across the four zones. Based on this reassignment,
it is found that four TV band channels (or 32MHz) are sufficient to provide the
existing UHF TV band coverage in India.


title: On Rapidity Divergences in the Soft and Collinear Limits of QCD

abstract:
  We consider the definition of a transverse-momentum-dependent parton
distribution function (TMDPDF) and its evolution properties given a
factorization theorem of Drell- Yan lepton pair production with a non-vanishing
transverse momentum. We discuss rapidity divergences that exist in both limits
of QCD: the soft and collinear. We argue that only when a specific combination
of the soft and collinear matrix elements is formed, rapidity divergences
cancel. We also argue that the soft matrix element, calculated in perturbation
theory, contains only rapidity divergences and there is no genuine
long-distance infra-red divergences.


title: Dynamical Properties of Gaussian Thermostats

abstract:
  In this work we show that the set of Kupka-Smale Gaussian thermostats on a
compact manifold is generic. A Gaussian thermostat is Kupka-Smale if the closed
orbits are hyperbolic and the heteroclinic intersection are transversal.
  We also show a dichotomy between robust transitivity and existence of
arbitrary number of attractors or repellers orbits. The main tools are the
concept of transitions adapted to the conformally symplectic context and a
perturbative theorem which is a version of the Franks lemma for Gaussian
thermostats.
  Finally we provide some conditions in terms of geometrical invariants for an
invariant set of a Gaussian thermostat to have dominated splitting. From that
we conclude some dynamical properties for the surface case.


title: Wavelet transform on the torus: a group theoretical approach

abstract:
  We construct a Continuous Wavelet Transform (CWT) on the torus $\mathbb T^2$
following a group-theoretical approach based on the conformal group $SO(2,2)$.
The Euclidean limit reproduces wavelets on the plane $\mathbb R^2$ with two
dilations, which can be defined through the natural tensor product
representation of usual wavelets on $\mathbb R$. Restricting ourselves to a
single dilation imposes severe conditions for the mother wavelet that can be
overcome by adding extra modular group $SL(2,\mathbb Z)$ transformations, thus
leading to the concept of \emph{modular wavelets}. We define modular-admissible
functions and prove frame conditions.


title: Performance of the LHCb High Level Trigger in 2012

abstract:
  The trigger system of the LHCb experiment is discussed in this paper and its
performance is evaluated on a dataset recorded during the 2012 run of the LHC.
The main purpose of the LHCb trigger system is to separate heavy flavour
signals from the light quark background. The trigger reduces the roughly 11MHz
of bunch-bunch crossings with inelastic collisions to a rate of 5kHz, which is
written to storage.


title: Axion Dark Matter Detection using an LC Circuit

abstract:
  It is shown that dark matter axions cause an oscillating electric current to
flow along magnetic field lines. The oscillating current induced in a strong
magnetic field $\vec{B}_0$ produces a small magnetic field $\vec{B}_a$. We
propose to amplify and detect $\vec{B}_a$ using a cooled LC circuit and a very
sensitive magnetometer. This appears to be a suitable approach to searching for
axion dark matter in the $10^{-7}$ to $10^{-9}$ eV mass range.


title:
Spectroscopic and physical parameters of Galactic O-type stars. II.
  Observational constraints on projected rotational and extra broadening
  velocities as a function of fundamental parameters and stellar evolution

abstract:
  Rotation is of key importance for the evolution of hot massive stars,
however, the rotational velocities of these stars are difficult to determine.
Based on our own data for 31 Galactic O stars and incorporating similar data
for 86 OB supergiants from the literature, we aim at investigating the
properties of rotational and extra line-broadening as a function of stellar
parameters and at testing model predictions about the evolution of stellar
rotation. Fundamental stellar parameters were determined by means of the code
FASTWIND. Projected rotational and extra broadening velocities originate from a
combined Ft + GOF method. Model calculations published previously were used to
estimate the initial evolutionary masses. The sample O stars with Minit > 50
Msun rotate with less that 26% of their break-up velocity, and they also lack
objects with v sin i < 50 km/s. For the stars with Minit > 35 Msun on the
hotter side of the bi-stability jump, the observed and predicted rotational
rates agree quite well; for those on the cooler side of the jump, the measured
velocities are systematically higher than the predicted ones. In general, the
derived extra broadening velocities decrease toward cooler Teff, whilst for
later evolutionary phases they appear, at the same v sin i, higher for
high-mass stars than for low-mass ones. None of the sample stars shows extra
broadening velocities higher than 110 km/s. For the majority of the more
massive stars, extra broadening either dominates or is in strong competition
with rotation. Conclusions: For OB stars of solar metallicity, extra broadening
is important and has to be accounted for in the analysis. When appearing at or
close to the zero-age main sequence, most of the single and more massive stars
rotate slower than previously thought. Model predictions for the evolution of
rotation in hot massive stars may need to be updated.


title: Neutrino induced charged-current coherent $\rho$ production

abstract:
  We present the latest results of coherent $\rho$ (Coh$\rho$) production using
the large data set collected by the NOMAD detector in which the momenta,
charges, and photons are precisely measured. We discuss the application of
using Coh$\rho$ process to constrain the neutrino flux with the proposed
Long-Baseline Neutrino Experiment Near Detector, the high resolution Straw Tube
Tracker.


title:
Novel dielectric anomalies due to spin-chains above and below Neel
  temperature in Ca3Co2O6

abstract:
  We bring out novel dielectric behavior of a spin-chain compound, Ca3Co2O6,
undergoing Neel order at (T_N=) 24 K. It is found that the virgin curve in the
plot of isothermal dielectric constant versus magnetic-field lies outside the
'butterfly-shaped' envelope curve well below T_N (e.g., 2.6 K), with a
signature of a partial arrest of the high-field magnetoelectric ME) phase in
zero-field after travelling through magnetic-field-induced magnetic
transitions. This behavior is in contrast to that observed in the isothermal
magnetization data. Thus, this work brings out a novel case for
'phase-coexistence phenomenon' due to ME coupling. Another strange finding is
that there is a weak, but a broad, peak in dielectric constant around 85 - 115
K well above T_N, attributable to incipient spin-chain magnetic ordering. This
finding should inspire further work to study ME coupling on artificial
assemblies of magnetic chains, also keeping in mind miniaturization required
for possible applications.


title: $V$-filtrations in positive characteristic and test modules

abstract:
  Let $R$ be a ring essentially of finite type over an $F$-finite field. Given
an ideal $\mathfrak{a}$ and a principal Cartier module $M$ we introduce the
notion of a $V$-filtration of $M$ along $\mathfrak{a}$. If $M$ is $F$-regular
then this coincides with the test module filtration. We also show that the
associated graded induces a functor $Gr^{[0,1]}$ from Cartier crystals to
Cartier crystals supported on $V(\mathfrak{a})$. This functor commutes with
finite pushforwards for principal ideals and with pullbacks along essentially
\'etale morphisms. We also derive corresponding transformation rules for test
modules generalizing previous results by Schwede and Tucker in the \'etale case
(cf. arXiv:1003.4333).
  If $\mathfrak{a} = (f)$ defines a smooth hypersurface and $R$ is in addition
regular then for a Cartier crystal corresponding to a locally constant sheaf on
$\Spec R_{\acute{e}t}$ the functor $Gr^{[0,1]}$ corresponds, up to a shift, to
$i^!$, where $i: V(\mathfrak{a}) \to \Spec R$ is the closed immersion.


title:
Analytical Study of Giant Fluctuations and Temporal Intermittency in an
  Aggregation Model

abstract:
  We study analytically giant fluctuations and temporal intermittency in a
stochastic one-dimensional model with diffusion and aggregation of masses in
the bulk, along with influx of single particles and outflux of aggregates at
the boundaries. We calculate various static and dynamical properties of the
total mass in the system for both biased and unbiased movement of particles and
different boundary conditions. These calculations show that (i) in the unbiased
case, the total mass has a non-Gaussian distribution and shows giant
fluctuations which scale as system size (ii) in all the cases, the system shows
strong intermittency in time, which is manifested in the anomalous scaling of
the dynamical structure functions of the total mass. The results are derived by
taking a continuum limit in space and agree well with numerical simulations
performed on the discrete lattice. The analytic results obtained here are
typical of the full phase of a more general model with fragmentation, which was
studied earlier using numerical simulations.


title:
Signatures of electron-magnon interaction in charge and spin currents in
  magnetic tunnel junctions: A nonequilibrium many-body perturbation theory
  approach

abstract:
  We develop a numerically exact scheme for resumming certain classes of
Feynman diagrams in the self-consistent perturbation expansion for the electron
and magnon self-energies in the nonequilibrium Green function formalism applied
to a coupled electron-magnon (\mbox{e-m}) system which is driven out of
equilibrium by the applied finite bias voltage. Our scheme operates with the
electronic and magnonic GFs and the corresponding self-energies viewed as
matrices in the Keldysh space, rather than conventionally extracting their
retarded and lesser components. This is employed to understand the effect of
inelastic \mbox{e-m} scattering on charge and spin current vs. bias voltage
$V_b$ in F/I/F magnetic tunnel junctions (MTJs), which are modeled on a
one-dimensional (1D) tight-binding lattice for the electronic subsystem and 1D
Heisenberg model for the magnonic subsystem. For this purpose, we evaluate Fock
diagram for the electronic self-energy and the electron-hole polarization
bubble diagram for the magnonic self-energy. The respective electronic and
magnonic GF lines within these diagrams are the fully interacting ones, thereby
requiring to solve the ensuing coupled system of nonlinear integral equations
self-consistently. Despite using the 1D model and treating \mbox{e-m}
interaction in many-body fashion only within a small active region consisting
of few lattice sites around the F/I interface, our analysis captures essential
features of the so-called zero-bias anomaly observed in both MgO- and
AlO$_x$-based realistic 3D MTJs where the second derivative $d^2 I/dV_b^2$
(i.e., inelastic electron tunneling spectrum) of charge current exhibits sharp
peaks of opposite sign on either side of the zero bias voltage.


title: Two-Dimensional Quantum Geometry

abstract:
  In these lectures we review our present understanding of the fractal
structure of two-dimensional Euclidean quantum gravity coupled to matter.


title:
Frequency dependence of H\"older continuity for quasiperiodic
  Schr\"odinger operators

abstract:
  We prove estimates on the H\"older exponent of the density of states measure
for discrete Schr\"odinger operators with potential of the form $V(n) =
\lambda(\lfloor(n+1)\beta\rfloor - \lfloor n\beta\rfloor)$, with $\lambda$
large enough, and conclude that for almost all values of $\beta$, the density
of states measure is not H\"older continuous.


title: How cells feel: stochastic model for a molecular mechanosensor

abstract:
  Understanding mechanosensitivity, i.e. how cells sense the stiffness of their
environment is very important, yet there is a fundamental difficulty in
understanding its mechanism: to measure an elastic modulus one requires two
points of application of force - a measuring and a reference point. The cell in
contact with substrate has only one (adhesion) point to work with, and thus a
new method of measurement needs to be invented. The aim of this theoretical
work is to develop a self-consistent physical model for mechanosensitivity, a
process by which a cell detects the mechanical stiffness of its environment
(e.g. a substrate it is attached to via adhesion points) and generates an
appropriate chemical signaling to remodel itself in response to this
environment. The model uses the molecular mechanosensing complex of latent
TGF-$\beta$ attached to the adhesion point as the biomarker. We show that the
underlying Brownian motion in the substrate is the reference element in the
measuring process. The model produces the closed expression for the rate of
release of active TGF-$\beta$, which depends on the substrate stiffness and the
pulling force coming from the cell in a subtle and non-trivial way. It is
consistent with basic experimental data showing an increase in signal for
stiffer substrates and higher pulling forces. In addition, we find that for
each cell there is a range of stiffness where a homeostatic configuration of
the cell can be achieved, outside of which the cell either relaxes its
cytoskeletal forces and detaches from the very weak substrate, or generates an
increasingly strong pulling force through stress fibers with a positive
feedback loop on very stiff substrates. In this way, the theory offers the
underlying mechanism for the myofibroblast conversion in wound healing and
smooth muscle cell dysfunction in cardiac disease.


title: Review of lattice results concerning low energy particle physics

abstract:
  We review lattice results related to pion, kaon, D- and B-meson physics with
the aim of making them easily accessible to the particle physics community.
More specifically, we report on the determination of the light-quark masses,
the form factor f+(0), arising in semileptonic K -> pi transition at zero
momentum transfer, as well as the decay constant ratio fK/fpi of decay
constants and its consequences for the CKM matrix elements Vus and Vud.
Furthermore, we describe the results obtained on the lattice for some of the
low-energy constants of SU(2)LxSU(2)R and SU(3)LxSU(3)R Chiral Perturbation
Theory and review the determination of the BK parameter of neutral kaon mixing.
The inclusion of heavy-quark quantities significantly expands the FLAG scope
with respect to the previous review. Therefore, for this review, we focus on D-
and B-meson decay constants, form factors, and mixing parameters, since these
are most relevant for the determination of CKM matrix elements and the global
CKM unitarity-triangle fit. In addition we review the status of lattice
determinations of the strong coupling constant alpha_s.


title: On the Positive Moments of Ranks of Partitions

abstract:
  By introducing $k$-marked Durfee symbols, Andrews found a combinatorial
interpretation of $2k$-th symmetrized moment $\eta_{2k}(n)$ of ranks of
partitions of $n$ in terms of $(k+1)$-marked Durfee symbols of $n$. In this
paper, we consider the $k$-th symmetrized positive moment $\bar{\eta}_k(n)$ of
ranks of partitions of $n$ which is defined as the truncated sum over positive
ranks of partitions of $n$. As combintorial interpretations of
$\bar{\eta}_{2k}(n)$ and $\bar{\eta}_{2k-1}(n)$, we show that for fixed $k$ and
$i$ with $1\leq i\leq k+1$, $\bar{\eta}_{2k-1}(n)$ equals the number of
$(k+1)$-marked Durfee symbols of $n$ with the $i$-th rank being zero and
$\bar{\eta}_{2k}(n)$ equals the number of $(k+1)$-marked Durfee symbols of $n$
with the $i$-th rank being positive. The interpretations of
$\bar{\eta}_{2k-1}(n)$ and $\bar{\eta}_{2k}(n)$ also imply the interpretation
of $\eta_{2k}(n)$ given by Andrews since $\eta_{2k}(n)$ equals
$\bar{\eta}_{2k-1}(n)$ plus twice of $\bar{\eta}_{2k}(n)$. Moreover, we obtain
the generating functions of $\bar{\eta}_{2k}(n)$ and $\bar{\eta}_{2k-1}(n)$.


title: Nonlinear dynamics of autonomous vehicles with limits on acceleration

abstract:
  The stability of autonomous vehicle platoons with limits on acceleration and
deceleration is determined. If the leading-vehicle acceleration remains within
the limits, all vehicles in the platoon remain within the limits when the
relative-velocity feedback coefficient is equal to the headway time constant.
Furthermore, if the sensitivity alpha is greater than the relative-velocity
feedback coefficient k, no collisions occur. String stability for small
perturbations is assumed and the initial condition is taken as the equilibrium
state. Other values of k and alpha that give stability with no collisions are
found from simulations. For vehicles with non-negligible mechanical response,
simulations indicate that the acceleration-feedback-control gain might have to
be dynamically adjusted to obtain optimal performance as the response time
changes with engine speed. Stability is demonstrated for some perturbations
that cause initial acceleration or deceleration greater than the limits, yet do
not cause collisions.


title:
Studies of Variability in Proto-Planetary Nebulae: II. Light and
  Velocity Curve Analyses of Iras 22272+5435 and 22223+4327

abstract:
  We have carried out a detailed observational study of the light, color, and
velocity variations of two bright, carbon-rich proto-planetary nebulae, IRAS
22223+4327 and 22272+5435. The light curves are based upon our observations
from 1994 to 2011, together with published data by Arkhipova and collaborators.
They each display four significant periods, with primary periods for IRAS
22223+4327 and 22272+5435 being 90 and 132 days, respectively. For each of
them, the ratio of secondary to primary period is 0.95, a value much different
from that found in Cepheids, but which may be characteristic of post-AGB stars.
Fewer significant periods are found in the smaller radial velocity data sets,
but they agree with those of the light curves. The color curves generally mimic
the light curves, with the objects reddest when faintest. A comparison in
seasons when there exist contemporaneous light, color, and velocity curves
reveals that the light and color curves are in phase, while the radial velocity
curves are 0.25 out of phase with the light curves. Thus they differ from what
is seen in Cepheids, in which the radial velocity curve is 0.50 P out of phase
with the light curve. Comparison of the observed periods and amplitudes with
those of post-AGB pulsation models shows poor agreement, especially for the
periods, which are much longer than predicted. These observational data,
particularly the contemporaneous light, color, and velocity curves, provide an
excellent benchmark for new pulsation models of cool stars in the post-AGB,
proto-planetary nebula phase.


title:
Extremal graphs for the sum of the two largest signless Laplacian
  eigenvalues

abstract:
  Let G be a simple graph on $n$ vertices and $e(G)$ edges. Consider $Q(G) = D
+ A$ as the signless Laplacian of $G$, where $A$ is the adjacency matrix and
$D$ is the diagonal matrix of the vertices degree of $G$. Let $q_1(G)$ and
$q_2(G)$ be the first and the second largest eigenvalues of $Q(G),$
respectively, and denote by $S_{n}^{+}$ the star graph plus one edge. In this
paper, we prove that inequality $q_1(G)+ q_2(G) <= e(G)+3$ is tighter for the
graph $S_{n}^{+}$ among all firefly graphs and also tighter to $S_{n}^{+}$ than
to the graphs $K_{k} \vee \overline{K_{n-k}}$ recently presented by Ashraf,
Omidi and Tayfeh-Rezaie. Also, we conjecture that the same inequality is
tighter to $S_{n}^{+}$ than any other graph on $n$ vertices.


title:
Synchrony and Periodicity in an Excitable Stochastic Neural Network with
  Multiple Subpopulations

abstract:
  We consider a fully stochastic excitatory neuronal network with a number of
subpopulations with different firing rates. We show that as network size goes
to infinity, this limits on a deterministic hybrid model whose trajectories are
discontinuous. The jumps in the limit correspond to large synchronous events
that involve a large proportion of the network. We also perform a rigorous
analysis of the limiting deterministic system in certain cases, and show that
it displays synchrony and periodicity in a large region of parameter space.


title:
Detection of Large Color Variation of Potentially Hazardous Asteroid
  (297274) 1996 SK

abstract:
  Low-inclination Near-Earth Asteroid (297274) 1996 SK, which is also
classified as a Potentially Hazardous Asteroid, has a highly eccentric orbit.
It was studied by multi-wavelength photometry within the framework of an NEA
color survey at the Lulin Observatory. We report here the finding of large
color variation across the surface of (297274) 1996 SK within one asteroidal
rotation period of $4.656\pm0.122$ hours and classify it as a S-type asteroid
according to its average colors of $B-V=0.767\pm0.033$, $V-R=0.482\pm0.021$,
$V-I=0.801\pm0.025$ and the corresponding relative reflectance spectrum. It
might be indicative of differential space weathering effect or compositional
inhomogeneity of the surface materials.


title:
Topological quantum phase transitions and edge states in spin-orbital
  coupled Fermi gases

abstract:
  We study the superconducting state in the presence of spin-orbital coupling
and the Zeeman field. It is found that a phase transition from the
Fulde-Ferrell-Larkin-Ovchinnikov state to the topological superconducting state
occurs upon increasing the spin-orbital coupling. The nature of this
topological phase transition and its critical property are investigated
numerically. Physical properties of topological superconducting phase are also
explored. Moreover, the local density of states is calculated, through which
the topological feature may be tested experimentally.


title:
The images of non-commutative polynomials evaluated on $2\times 2$
  matrices over an arbitrary field

abstract:
  Let $p$ be a multilinear polynomial in several non-commuting variables with
coefficients in an arbitrary field $K$. Kaplansky conjectured that for any $n$,
the image of $p$ evaluated on the set $M_n(K)$ of $n$ by $n$ matrices is either
zero, or the set of scalar matrices, or the set $sl_n(K)$ of matrices of trace
$0$, or all of $M_n(K)$. This conjecture was proved for $n=2$ when $K$ is
closed under quadratic extensions. In this paper the conjecture is verified for
$K=\mathbb{R}$ and $n=2$, also for semi-homogeneous polynomials $p$, with a
partial solution for an arbitrary field $K$.


title: Estimates for spectral density functions of matrices over C[Z^d]

abstract:
  We give a polynomial bound on the spectral density function of a matrix over
the complex group ring of Z^d. It yields an explicit lower bound on the
Novikov-Shubin invariant associated to this matrix showing in particular that
the Novikov-Shubin invariant is larger than zero.


title: Local order variations in confined hard-sphere fluids

abstract:
  Pair distributions of fluids confined between two surfaces at close distance
are of fundamental importance for a variety of physical, chemical, and
biological phenomena, such as interactions between macromolecules in solution,
surface forces, and diffusion in narrow pores. However, in contrast to bulk
fluids, properties of inhomogeneous fluids are seldom studied at the
pair-distribution level. Motivated by recent experimental advances in
determining anisotropic structure factors of confined fluids, we analyze
theoretically the underlying anisotropic pair distributions of the archetypical
hard-sphere fluid confined between two parallel hard surfaces using
first-principles statistical mechanics of inhomogeneous fluids. For this
purpose, we introduce an experimentally accessible ensemble-averaged local
density correlation function and study its behavior as a function of confining
slit width. Upon increasing the distance between the confining surfaces, we
observe an alternating sequence of strongly anisotropic versus more isotropic
local order. The latter is due to packing frustration of the spherical
particles. This observation highlights the importance of studying inhomogeneous
fluids at the pair-distribution level.


title: 1-supertransitive subfactors with index at most 6+1/5

abstract:
  We classify irreducible II_1 subfactors A \subset B such that B \ominus A is
reducible as an A-A bimodule, with index at most 6+1/5, leaving aside the
composite subfactors at index exactly 6. Previous work has already achieved
this up to index 3+\sqrt{5} \approx 5.23. We find there are exactly three such
subfactors with index in (3+\sqrt{5}, 6+1/5], all with index 3+2\sqrt{2}. One
of these comes from SO(3)_q at a root of unity, while the other two appear to
be closely related, and are `braided up to a sign'.


title: Magnetic Field Induced Radius Inflation of Low-Mass Stars

abstract:
  We present results obtained using the magnetic Dartmouth stellar evolution
code that address the possibility that magnetic fields are inflating low-mass
stars in detached eclipsing binaries. While it seems plausible that magnetic
fields are inflating stars with radiative cores, the level of inflation
observed among fully convective stars appears too large to be explained by
magnetic fields. We provide an alternative explanation, stellar metallicity,
and propose observations that can help further constrain stellar models.


title:
Translating Specifications in a Dependently Typed Lambda Calculus into a
  Predicate Logic Form

abstract:
  Dependently typed lambda calculi such as the Edinburgh Logical Framework (LF)
are a popular means for encoding rule-based specifications concerning formal
syntactic objects. In these frameworks, relations over terms representing
formal objects are naturally captured by making use of the dependent structure
of types. We consider here the meaning-preserving translation of specifications
written in this style into a predicate logic over simply typed {\lambda}-terms.
Such a translation can provide the basis for efficient implementation and
sophisticated capabilities for reasoning about specifications. We start with a
previously described translation of LF specifications to formulas in the logic
of higher-order hereditary Harrop (hohh) formulas. We show how this translation
can be improved by recognizing and eliminating redundant type checking
information contained in it. This benefits both the clarity of translated
formulas, and reduces the effort which must be spent on type checking during
execution. To allow this translation to be used to execute LF specifications,
we describe an inverse transformation from hohh terms to LF expressions; thus
computations can be carried out using the translated form and the results can
then be exported back into LF. Execution based on LF specifications may also
involve some forms of type reconstruction. We discuss the possibility of
supporting such a capability using the translation under some reasonable
restrictions on the structure of specifications.


title:
Molecular hydrogen in the z = 2.66 damped Lyman-alpha absorber toward Q
  J0643-5041

abstract:
  We use high signal-to-noise ratio, high-resolution VLT-UVES data of Q
J0643-5041 amounting to a total of more than 23 hours exposure time and fit the
neutral hydrogen, metals and H2 absorption features with multiple-component
Voigt profiles. We study the relative populations of H2 rotational levels and
the fine-structure excitation of neutral carbon to determine the physical
conditions in the H2-bearing cloud. We find some evidence for part of the
quasar broad line emission region not being fully covered by the H2-bearing
cloud. We measure a total neutral hydrogen column density of log N(H) = 21.03
+/- 0.08. Molecular hydrogen is detected in several rotational levels, possibly
up to J = 7, in a single component. The corresponding molecular fraction is log
f = -2.19+0.07-0.08, where f = 2N(H2)/(2N(H2)+N(H)). The H2 Doppler parameter
is of the order of 1.5 km/s for J = 0, 1 and 2 and larger for J>2. The
molecular component has a kinetic temperature of T = 80 K, which yields a mean
thermal velocity of about 1 km/s, consistent with the Doppler broadening of the
lines. The UV ambient flux is of the order of the mean ISM Galactic flux. We
discuss the possible detection of HD and derive an upper limit of log N(HD) <
13.65 +/- 0.07 leading to log HD/(2 H2) < -5.19 +/- 0.07 which is consistently
lower than the primordial D/H ratio. Metals span about 210 km/s with [Zn/H] =
-0.91 +/- 0.09 relative to solar, with iron depleted relative to zinc [Zn/Fe] =
0.45 +/- 0.06, and with the rare detection of copper. We follow the procedures
used in our previous works to derive a constraint on the cosmological variation
of the proton-to-electron mass ratio of (7.4 +/- 4.3 (stat) +/- 5.1 (syst))
ppm.


title:
Local deterministic simulation of equatorial Von Neumann measurements on
  tripartite GHZ state

abstract:
  Experimental free-will or measurement independence is one of the crucial
assumptions in derivation of any nonlocal theorem. Any nonlocal correlation
obtained in quantum world can have a local deterministic explanation if there
is no experimental free-will in choosing the measurement settings. Recently, in
[Phys. Rev. Lett. {\bf105}, 250404 (2010)] it has been shown that to obtain a
local deterministic description for singlet state correlation one does not need
to give up measurement independence completely, but a partial measurement
dependence suffices. In three party scenario considering GHZ correlation one
can exhibit absolute contradiction between quantum theory and local realism. In
this paper we show that such correlation also has local deterministic
description if measurement independence is given up, even if not completely. We
provide a local deterministic model for equatorial Von Neumann measurements on
tripartite GHZ state by sacrificing measurement independence partially.


title:
Probing a cosmological model with a $\Lambda = \Lambda_0 + 3\beta H^2$
  decaying-vacuum

abstract:
  In this work we study the evolution of matter-density perturbations for an
arbitrary $\Lambda(t)$ model, and specialize our analysis to the particular
phenomenological law $\Lambda = \Lambda_0 + 3\beta H^2$. We study the evolution
of the cosmic star formation rate in this particular dark energy scenario and,
by constraining the $\beta$ parameter using both the age of the universe and
the cosmic star formation rate curve, we show that it leads to a reasonable
physical model for $\beta\lesssim 0.1$.


title:
On sums involving products and quotients of L-functions over function
  fields

abstract:
  We estimate the sum of products or quotients of $L$-functions, where the sum
is taken over all quadratic extensions of given genus over a fixed global
function field. Our estimate for the sum of the quotient of two $L$-functions
is analogous to a result of Schmidt where he estimates the sum of the quotient
of two $L$-series, where the sum is over quadratic extensions of $\bq$ with
absolute value of the discriminant less than a given bound.


title:
An optimally concentrated Gabor transform for localized time-frequency
  components

abstract:
  Gabor analysis is one of the most common instances of time-frequency signal
analysis. Choosing a suitable window for the Gabor transform of a signal is
often a challenge for practical applications, in particular in audio signal
processing. Many time-frequency (TF) patterns of different shapes may be
present in a signal and they can not all be sparsely represented in the same
spectrogram. We propose several algorithms, which provide optimal windows for a
user-selected TF pattern with respect to different concentration criteria. We
base our optimization algorithm on $l^p$-norms as measure of TF spreading. For
a given number of sampling points in the TF plane we also propose optimal
lattices to be used with the obtained windows. We illustrate the potentiality
of the method on selected numerical examples.


title: Spatial statistics, image analysis and percolation theory

abstract:
  We develop a novel method for detection of signals and reconstruction of
images in the presence of random noise. The method uses results from
percolation theory. We specifically address the problem of detection of
multiple objects of unknown shapes in the case of nonparametric noise. The
noise density is unknown and can be heavy-tailed. The objects of interest have
unknown varying intensities. No boundary shape constraints are imposed on the
objects, only a set of weak bulk conditions is required. We view the object
detection problem as a multiple hypothesis testing for discrete statistical
inverse problems. We present an algorithm that allows to detect greyscale
objects of various shapes in noisy images. We prove results on consistency and
algorithmic complexity of our procedures. Applications to cryo-electron
microscopy are presented.


title: Si isotope homogeneity of the solar nebula

abstract:
  The presence or absence of variations in the mass-independent abundances of
Si isotopes in bulk meteorites provides important clues concerning the
evolution of the early solar system. No Si isotopic anomalies have been found
within the level of analytical precision of 15 ppm in 29Si/28Si across a wide
range of inner solar system materials, including terrestrial basalts,
chondrites, and achondrites. A possible exception is the angrites, which may
exhibit small excesses of 29Si. However, the general absence of anomalies
suggests that primitive meteorites and differentiated planetesimals formed in a
reservoir that was isotopically homogenous with respect to Si. Furthermore, the
lack of resolvable anomalies in the Calcium-Aluminum-rich Inclusion measured
here suggests that any nucleosynthetic anomalies in Si isotopes were erased
through mixing in the solar nebula prior to the formation of refractory solids.
The homogeneity exhibited by Si isotopes may have implications for the
distribution of Mg isotopes in the solar nebula. Based on supernova
nucleosynthetic yield calculations, the expected magnitude of heavy-isotope
overabundance is larger for Si than for Mg, suggesting that any potential Mg
heterogeneity, if present, exists below the 15 ppm level.


title:
Star forming regions linked to RCW78 and the discovery of a new IR
  bubble

abstract:
  With the aim of investigating the presence of molecular and dust clumps
linked to two star forming regions identified in the expanding molecular
envelope of the stellar wind bubble RCW78, we analyzed the distribution of the
molecular gas and cold dust. To accomplish this study we performed dust
continuum observations at 870 \mu m and 13CO(2-1) line observations with the
APEX telescope, using LABOCA and SHeFI-1 instruments, respectively, and
analyzed Herschel images at 70, 160, 250, 350, and 500 \mu m. These
observations allowed us to identify cold dust clumps linked to region B (named
the Southern clump) and region C (clumps 1 and 2) and an elongated Filament.
Molecular gas was clearly detected linked to the Southern clump and the
Filament. The velocity of the molecular gas is compatible with the location of
the dense gas in the expanding envelope of RCW78. We estimate dust temperatures
and total masses for the dust condensations from the emissions at different
wavelengths in the far-IR and from the molecular line using LTE and the virial
theorem. Masses obtained through different methods agree within a factor of
2-6. CC-diagrams and SED analysis of young stellar objects confirmed the
presence of intermediate and low mass YSOs in the dust regions, indicating that
moderate star formation is present. In particular, a cluster of IR sources was
identified inside the Southern clump. The IRAC image at 8 \mu m revealed the
existence of an infrared dust bubble of 16 arcsec in radius probably linked to
the O-type star HD117797 located at 4 kpc. The distribution of the near and mid
infrared emission indicate that warm dust is associated with the bubble.


title:
Optimized Principal Component Analysis on Coronagraphic Images of the
  Fomalhaut System

abstract:
  We present the results of a study to optimize the principal component
analysis (PCA) algorithm for planet detection, a new algorithm complementing
ADI and LOCI for increasing the contrast achievable next to a bright star. The
stellar PSF is constructed by removing linear combinations of principal
components, allowing the flux from an extrasolar planet to shine through. The
number of principal components used determines how well the stellar PSF is
globally modelled. Using more principal components may decrease the number of
speckles in the final image, but also increases the background noise. We apply
PCA to Fomalhaut VLT NaCo images acquired at 4.05 micron with an apodized phase
plate. We do not detect any companions, with a model dependent upper mass limit
of 13-18 M_Jup from 4-10 AU. PCA achieves greater sensitivity than the LOCI
algorithm for the Fomalhaut coronagraphic data by up to 1 magnitude. We make
several adaptations to the PCA code and determine which of these prove the most
effective at maximizing the signal-to-noise from a planet very close to its
parent star. We demonstrate that optimizing the number of principal components
used in PCA proves most effective for pulling out a planet signal.


title:
Dirac edges of fractal magnetic minibands in graphene with hexagonal
  moire superlattices

abstract:
  We find a systematic reappearance of massive Dirac features at the edges of
consecutive minibands formed at magnetic fields B_{p/q}= p\phi_0/(qS) providing
rational magnetic flux through a unit cell of the moire superlattice created by
a hexagonal substrate for electrons in graphene. The Dirac-type features in the
minibands at B=B_{p/q} determine a hierarchy of gaps in the surrounding fractal
spectrum, and show that these minibands have topological insulator properties.
Using the additional $q$-fold degeneracy of magnetic minibands at B_{p/q}, we
trace the hierarchy of the gaps to their manifestation in the form of
incompressible states upon variation of the carrier density and magnetic field.


title: Finite field-dependent symmetries in perturbative quantum gravity

abstract:
  In this paper we discuss the absolutely anticommuting nilpotent symmetries
for perturbative quantum gravity in general curved spacetime in linear and
non-linear gauges. Further, we analyze the finite field-dependent BRST (FFBRST)
transformation for perturbative quantum gravity in general curved spacetime.
The FFBRST transformation changes the gauge-fixing and ghost parts of the
perturbative quantum gravity within functional integration. However, the
operation of such symmetry transformation on the generating functional of
perturbative quantum gravity does not affect the theory on physical ground. The
FFBRST transformation with appropriate choices of finite BRST parameter
connects non-linear Curci--Ferrari and Landau gauges of perturbative quantum
gravity. The validity of the results is also established at quantum level using
Batalin-Vilkovisky (BV) formulation.


title: Homological stability for unlinked circles in a 3-manifold

abstract:
  We prove a homological stability theorem for unlinked circles in
$3$-manifolds and give an application to certain groups of diffeomorphisms of
3-manifolds.


title: Chemical signatures of planets: beyond solar-twins

abstract:
  Elemental abundance studies of solar twin stars suggest that the solar
chemical composition contains signatures of the formation of terrestrial
planets in the solar system, namely small but significant depletions of the
refractory elements. To test this hypothesis, we study stars which, compared to
solar twins, have less massive convective envelopes (therefore increasing the
amplitude of the predicted effect) or are, arguably, more likely to host
planets (thus increasing the frequency of signature detections). We measure
relative atmospheric parameters and elemental abundances of a late-F type dwarf
sample (52 stars) and a sample of metal-rich solar analogs (59 stars). We
detect refractory-element depletions with amplitudes up to about 0.15 dex. The
distribution of depletion amplitudes for stars known to host gas giant planets
is not different from that of the rest of stars. The maximum amplitude of
depletion increases with effective temperature from 5650 K to 5950 K, while it
appears to be constant for warmer stars (up to 6300 K). The depletions observed
in solar twin stars have a maximum amplitude that is very similar to that seen
here for both of our samples. Gas giant planet formation alone cannot explain
the observed distributions of refractory-element depletions, leaving the
formation of rocky material as a more likely explanation of our observations.
More rocky material is necessary to explain the data of solar twins than
metal-rich stars, and less for warm stars. However, the sizes of the stars'
convective envelopes at the time of planet formation could be regulating these
amplitudes. Our results could be explained if disk lifetimes were shorter in
more massive stars, as independent observations indeed seem to suggest.


title: Log-Periodic Oscillations in the Photo Response of Efimov Trimers

abstract:
  The photoassociation of Efimov trimer, composed of three identical bosons, is
studied utilizing the multipole expansion. For identical particles the leading
contribution comes from the r^2 s-mode operator and from the quadrupole d-mode
operator. Log-periodic oscillations are found in the photoassociation response
function, both near the energy threshold for the leading s-wave reaction, and
in the high frequency tail for all partial waves.


title: A Hybrid Local Search for Simplified Protein Structure Prediction

abstract:
  Protein structure prediction based on Hydrophobic-Polar energy model
essentially becomes searching for a conformation having a compact hydrophobic
core at the center. The hydrophobic core minimizes the interaction energy
between the amino acids of the given protein. Local search algorithms can
quickly find very good conformations by moving repeatedly from the current
solution to its "best" neighbor. However, once such a compact hydrophobic core
is found, the search stagnates and spends enormous effort in quest of an
alternative core. In this paper, we attempt to restructure segments of a
conformation with such compact core. We select one large segment or a number of
small segments and apply exhaustive local search. We also apply a mix of
heuristics so that one heuristic can help escape local minima of another. We
evaluated our algorithm by using Face Centered Cubic (FCC) Lattice on a set of
standard benchmark proteins and obtain significantly better results than that
of the state-of-the-art methods.


title: Effects of Low vs. High Fermionic Modes on Hadron Mass Generation

abstract:
  A nonvanishing spectral density of the low-lying eigenmodes of the Dirac
operator naturally is a signal for dynamical chiral symmetry breaking
(D$\chi$SB) via the Banks-Casher relation. The low-lying eigenmodes alone
saturate the pseudoscalar channel and the corresponding propagator successfully
reproduces the pion mass. In this paper we investigate the effects on the mass
generation of hadrons other than pions. The evolution of these masses upon
inclusion of an increasing number of the low-lying eigenmodes is confronted
with the hadron mass spectrum upon removal of such eigenmodes.


title:
Speech animation using electromagnetic articulography as motion capture
  data

abstract:
  Electromagnetic articulography (EMA) captures the position and orientation of
a number of markers, attached to the articulators, during speech. As such, it
performs the same function for speech that conventional motion capture does for
full-body movements acquired with optical modalities, a long-time staple
technique of the animation industry. In this paper, EMA data is processed from
a motion-capture perspective and applied to the visualization of an existing
multimodal corpus of articulatory data, creating a kinematic 3D model of the
tongue and teeth by adapting a conventional motion capture based animation
paradigm. This is accomplished using off-the-shelf, open-source software. Such
an animated model can then be easily integrated into multimedia applications as
a digital asset, allowing the analysis of speech production in an intuitive and
accessible manner. The processing of the EMA data, its co-registration with 3D
data from vocal tract magnetic resonance imaging (MRI) and dental scans, and
the modeling workflow are presented in detail, and several issues discussed.


title:
Ground-State Phase Diagram of S=2 Heisenberg Chains with Alternating
  Single-Site Anisotropy

abstract:
  The ground-state phase diagram of $S=2$ antiferromagnetic Heisenberg chains
with coexisting uniform and alternating single-site anisotropies is
investigated by the numerical exact diagonalization and density matrix
renormalization group methods. We find the Haldane, large-$D$, N\'eel,
period-doubled N\'eel, gapless spin fluid, quantized and partial ferrimagnetic
phases. The Haldane phase is limited to the close neighborhood of the isotropic
point. Within numerical accuracy, the transition from the gapless spin-fluid
phase to the period-doubled N\'eel phase is a direct transition. Nevertheless,
the presence of a narrow spin-gap phase between these two phases is suggested
on the basis of the low-energy effective theory. The ferrimagnetic ground state
is present in a wide parameter range. This suggests the realization of
magnetized single-chain magnets with a uniform spin magnitude by controlling
the environment of each magnetic ion without introducing ferromagnetic
interactions.