title:
Ghost sector and geometry in minimal Landau gauge: further constraining
  the infinite-volume limit

abstract:
  We present improved upper and lower bounds for the momentum-space ghost
propagator of Yang-Mills theories in terms of the two smallest nonzero
eigenvalues (and their corresponding eigenvectors) of the Faddeev-Popov matrix.
These results are verified using data from four-dimensional numerical
simulations of SU(2) lattice gauge theory in minimal Landau gauge at beta =
2.2, for lattice sides N = 16, 32, 48 and 64. Gribov-copy effects are discussed
by considering four different sets of numerical minima. We then present a lower
bound for the smallest nonzero eigenvalue of the Faddeev-Popov matrix in terms
of the smallest nonzero momentum on the lattice and of a parameter
characterizing the geometry of the first Gribov region $\Omega$. This allows a
simple and intuitive description of the infinite-volume limit in the ghost
sector. In particular, we show how nonperturbative effects may be quantified by
the rate at which typical thermalized and gauge-fixed configurations approach
the boundary of Omega, known as the first Gribov horizon. As a result, a simple
and concrete explanation emerges for why lattice studies do not observe an
enhanced ghost propagator in the deep infrared limit. Most of the simulations
have been performed on the Blue Gene/P--IBM supercomputer shared by Rice
University and S\~ao Paulo University.


title:
The Networks Are Out There: Building Cultural and Economic Resilience
  Through Informal Communities of Practice

abstract:
  This paper explores the possibilities offered by informal communities of
practice to operate as "prototyping spaces" for innovation in the context of
developing economies. It begins by looking at the concept of "economic
complexity" and how it is useful in both guiding the priorities and evaluating
the challenges developing economies face when attempting to drive growth and
build measures of resilience, and raises the question of how these economies
can both introduce higher complexity activities while compensating for
latecomer disadvantages versus more complex economies. It then examines in
detail the case of the Twin Eagles Group, a Peruvian video game development
community in the 1990s, and how they reverse engineered technologies and global
practices to pursue their creative objectives. Based on this case, it concludes
by laying out some of the methodological challenges associated to researching
this sort of community because of the multi-sited nature of their activities.


title:
Transmission phase lapses through a quantum dot in a strong magnetic
  field

abstract:
  The phase of the transmission amplitude through a mesoscopic system contains
information about the system's quantum mechanical state and excitations
thereof. In the absence of an external magnetic field, abrupt phase lapses
occur between transmission resonances of quantum dots and can be related to the
signs of tunneling matrix elements. They are smeared at finite temperatures. By
contrast, we show here that in the presence of a strong magnetic field, phase
lapses represent a genuine interaction effect and may occur also on resonance.
For some realistic parameter range these phase lapses are robust against finite
temperature broadening.


title: On the Distribution of Values of Certain Word Maps

abstract:
  For any positive integers m and n, the word map (x,y) -> x^m y^n is almost
measure preserving on large finite simple groups G.


title:
Dynamics of Human Social Networks: People, Time, Relationships, and
  Places

abstract:
  The availability of advanced social interaction sensing technologies provides
fine grained data for social network analysis. Although traditional methods of
gathering social network data may be subject to human ability to recall social
details, people's rating of their closeness to persons in their network is
important. This study assesses the relationship amidst closeness ratings,
sensed interactions and shared places of recreation. The study found that
people tend to give high closeness ratings to people with whom they spend more
time. Shared places are correlated to social closeness ratings but not to
length of interactions. The results of this study highlight the importance of
sensed interactions and closeness ratings.


title: Strain engineering of topological properties in lead-salt semiconductors

abstract:
  Rock-salt chalcogenide SnTe represents the simplest realization of a
topological insulator where a crystal symmetry allows for the appearence of
topologically protected metallic states with an even number of Dirac cones on
high-symmetry crystal surfaces. Related rock-salt lead chalcogenides have been
predicted as well to undergo a phase-transition to a topological crystalline
insulating phase after band inversion induced by alloying and pressure. Here we
theoretically predict that strain, as realized in thin films grown on (001)
substrates, may induce such topological phase-transitions. Furthermore,
relevant topological properties of the surface states, such as the location of
the Dirac cones on the surface Brillouin zone or the decay length of edge
states, appear to be tunable with strain, with potential implications for
technological devices benefiting from those additional degrees of freedom.


title:
Macro-evolutionary models and coalescent point processes: The shape and
  probability of reconstructed phylogenies

abstract:
  Forward-time models of diversification (i.e., speciation and extinction)
produce phylogenetic trees that grow "vertically" as time goes by. Pruning the
extinct lineages out of such trees leads to natural models for reconstructed
trees (i.e., phylogenies of extant species). Alternatively, reconstructed trees
can be modelled by coalescent point processes (CPP), where trees grow
"horizontally" by the sequential addition of vertical edges. Each new edge
starts at some random speciation time and ends at the present time; speciation
times are drawn from the same distribution independently. CPP lead to extremely
fast computation of tree likelihoods and simulation of reconstructed trees.
Their topology always follows the uniform distribution on ranked tree shapes
(URT). We characterize which forward-time models lead to URT reconstructed
trees and among these, which lead to CPP reconstructed trees. We show that for
any "asymmetric" diversification model in which speciation rates only depend on
time and extinction rates only depend on time and on a non-heritable trait
(e.g., age), the reconstructed tree is CPP, even if extant species are
incompletely sampled. If rates additionally depend on the number of species,
the reconstructed tree is (only) URT (but not CPP). We characterize the common
distribution of speciation times in the CPP description, and discuss incomplete
species sampling as well as three special model cases in detail: 1) extinction
rate does not depend on a trait; 2) rates do not depend on time; 3) mass
extinctions may happen additionally at certain points in the past.


title: The Chemical Origin of SEY at Technical Surfaces

abstract:
  The secondary emission yield (SEY) properties of colaminated Cu samples for
LHC beam screens are correlated to the surface chemical composition determined
by X-ray photoelectron spectroscopy. The surface of the "as received" samples
is characterized by the presence of significant quantities of contaminating
adsorbates and by the maximum of the SEY curve (dmax) being as high as 2.2.
After extended electron scrubbing at kinetic energy of 10 and 500 eV, the dmax
value drops to the ultimate values of 1.35 and 1.1, respectively. In both cases
the surface oxidized phases are significantly reduced, whereas only in the
sample scrubbed at 500 eV the formation of a graphitic-like C layer is
observed. We find that the electron scrubbing of technical Cu surfaces can be
described as occurring in two steps, where the first step consists in the
electron induced desorption of weakly bound contaminants that occurs
indifferently at 10 and at 500 eV and corresponds to a partial decrease of
dmax, and the second step, activated by more energetic electrons and becoming
evident at high doses, which increases the number of graphitic-like C-C bonds
via the dissociation of adsorbates already contaminating the "as received"
surface or accumulating on this surface during irradiation. Our results
demonstrate how the kinetic energy of impinging electrons is a crucial
parameter when conditioning technical surfaces of Cu and other metals by means
of electron induced chemical processing.


title:
Constraining a class of B-L extended models from vacuum stability and
  perturbativity

abstract:
  The precise knowledge of the Standard Model Higgs boson and top quark masses
and couplings are crucial to understand the physics beyond it. SM like Higgs
boson having mass in the range of 123-127 GeV squeezes the parameters for
beyond standard model. In recent LHC era many TeV scale neutrino mass models
have earned much attention as they pose many interesting phenomenological
aspects. We have contemplated B-L extended models which are theoretically well
motivated and phenomenologically interesting, and successfully explain neutrino
mass generation. In this article we have analysed the detailed structures of
the scalar potentials for such models. We have computed the criteria which
guarantee that vacuum is bounded from below in all directions. Along with that
triviality and perturbativity bounds are also necessitated. Incorporating all
such effects we constrain the parameters of such models by performing their
renormalization group evolutions.


title:
Science Fiction as a Worldwide Phenomenon: A Study of International
  Creation, Consumption and Dissemination

abstract:
  This paper examines the international nature of science fiction. The focus of
this research is to determine whether science fiction is primarily English
speaking and Western or global; being created and consumed by people in
non-Western, non-English speaking countries? Science fiction's international
presence was found in three ways, by network analysis, by examining a online
retailer and with a survey. Condor, a program developed by GalaxyAdvisors was
used to determine if science fiction is being talked about by non-English
speakers. An analysis of the international Amazon.com websites was done to
discover if it was being consumed worldwide. A survey was also conducted to see
if people had experience with science fiction. All three research methods
revealed similar results. Science fiction was found to be international, with
science fiction creators originating in different countries and writing in a
host of different languages. English and non-English science fiction was being
created and consumed all over the world, not just in the English speaking West.


title:
Localization for a nonlinear sigma model in a strip related to vertex
  reinforced jump processes

abstract:
  We study a lattice sigma model which is expected to reflect Anderson
localization and delocalization transition for real symmetric band matrices in
3D, but describes the mixing measure for a vertex reinforced jump process too.
For this model we prove exponential localization at any temperature in a strip,
and more generally in any quasi-one dimensional graph, with pinning (mass) at
only one site. The proof uses a Mermin-Wagner type argument and a transfer
operator approach.

categories: math-ph cond-mat.stat-mech math.MP math.PR


title:
Doping and critical-temperature dependence of the energy gaps in
  Ba(Fe_{1-x}Co_x)_2As_2 thin films

abstract:
  The dependence of the superconducting gaps in epitaxial
Ba(Fe_{1-x}Co_{x})_2As_2 thin films on the nominal doping x (0.04 \leq x \leq
0.15) was studied by means of point-contact Andreev-reflection spectroscopy.
The normalized conductance curves were well fitted by using the 2D
Blonder-Tinkham-Klapwijk model with two nodeless, isotropic gaps -- although
the possible presence of gap anisotropies cannot be completely excluded. The
amplitudes of the two gaps \Delta_{S} and \Delta_{L} show similar monotonic
trends as a function of the local critical temperature T_{c}^{A} (measured in
the same point contacts) from 25 K down to 8 K. The dependence of the gaps on x
is well correlated to the trend of the critical temperature, i.e. to the shape
of the superconducting region in the phase diagram. When analyzed within a
simple three-band Eliashberg model, this trend turns out to be compatible with
a mechanism of superconducting coupling mediated by spin fluctuations, whose
characteristic energy scales with T_{c} according to the empirical law
\Omega_{0}= 4.65*k_{B}*T_{c}, and with a total electron-boson coupling strength
\lambda_{tot}= 2.22 for x \leq 0.10 (i.e. up to optimal doping) that slightly
decreases to \lambda_{tot}= 1.82 in the overdoped samples (x = 0.15).


title: Soft X-ray reflectivity: from quasi-perfect mirrors to accelerator walls

abstract:
  Reflection of light from surfaces is a very common, but complex phenomenon
not only in science and technology, but in every day life. The underlying basic
optical principles have been developed within the last five centuries using
visible light available from the sun or other laboratory light sources. X-rays
were detected in 1895, and the full potential of soft- and hard-x ray radiation
as a probe for the electronic and geometric properties of matter, for material
analysis and its characterisation is available only since the advent of
synchrotron radiation sources some 50 years ago. On the other hand
high-brilliance and high power synchrotron radiation of present-days 3rd and
4th generation light sources is not always beneficial. Highenergy machines and
accelerator-based light sources can suffer from a serious performance drop or
limitations due to interaction of the synchrotron radiation with the
accelerator walls, thus producing clouds of photoelectrons (e-cloud) which in
turn interact with the accelerated beam. Thus the suitable choice of
accelerator materials and their surface coating, which determines the x-ray
optical behaviour is of utmost importance to achieve ultimate emittance. Basic
optical principles and examples on reflectivity for selected materials are
given here.


title:
Towards Precise Ages and Masses of Free Floating Planetary Mass Brown
  Dwarfs

abstract:
  Measurement of the substellar initial mass function (IMF) in very young
clusters is hampered by the possibility of the age spread of cluster members.
This is particularly serious for candidate planetary mass objects (PMOs), which
have a very similar location to older and more massive brown dwarfs on the
Hertzsprung-Russell Diagram (HRD). This degeneracy can be lifted by the
measurement of gravity-sensitive spectral features. To this end we have
obtained medium resolution (R~5000) Near-infrared Integral Field Spectrometer
(NIFS) K band spectra of a sample of late M- / early L-type dwarfs. The sample
comprises old field dwarfs and very young brown dwarfs in the Taurus
association and in the Sigma Orionis cluster. We demonstrate a positive
correlation between the strengths of the 2.21micron NaI doublet and the
objects' ages. We demonstrate a further correlation between these objects' ages
and the shape of their K band spectra. We have quantified this correlation in
the form of a new index, the H2(K) index. This index appears to be more
gravity-sensitive than the NaI doublet and has the advantage that it can be
computed for spectra where gravity-sensitive spectral lines are unresolved,
while it is also more sensitive to surface gravity at very young ages (<10 Myr)
than the triangular H band peak. Both correlations differentiate young objects
from field dwarfs, while the H2(K) index can distinguish, at least
statistically, populations of ~1 Myr objects from populations of ~10 Myr
objects. We applied the H2(K) index to NIFS data for one Orion nebula cluster
(ONC) PMO and to previously published low resolution spectra for several other
ONC PMOs where the 2.21micron NaI doublet was unresolved and concluded that the
average age of the PMOs is ~1 Myr.


title: Double-discrete solitons in fishnet arrays of optical fibers

abstract:
  We demonstrate that crossed arrays of optical fibers support the
double-discrete linear and nonlinear propagation of light beams, in which not
only the transverse coordinate (the fiber's number) is discrete, but also the
longitudinal (propagation) coordinate, i.e., the number of the fiber-crossing
site, is effectively discrete too. In the linear limit, this transmission
regime features double-discrete self-collimation. The nonlinear fishnet arrays
with both focusing and defocusing nonlinearities give rise to double-discrete
spatial solitons. Solitons bifurcating from two different branches of the
linear dispersion relation feature strong interactions and form composite
states. In the continuum limit, the model of the nonlinear fishnet reduces to a
system of coupled-mode equations similar to those describing Bragg gratings,
but without the cross-phase-modulation terms.


title:
Description of ultracold atoms in a one-dimensional geometry of a
  harmonic trap with a realistic interaction

abstract:
  We compute the ground state energy of two atoms in a one-dimensional geometry
of a harmonic optical trap. We obtain a dependence of the energy on a
one-dimensional scattering length, which corresponds to various strengths of
the interaction potential of a gaussian type. The calculation is performed by
numerical and analytical methods. For the analytical method we choose the
oscillator representation method (OR), which has been successfully applied to
computations of bound states of various few-body systems. The main results of
this paper are: 1) numerical investigation of the validity range of the
previously used pseudopotential method; 2) investigation of the validity range
of the OR for a superposition of parabolic and gaussian potentials.


title: The uniform face ideals of a simplicial complex

abstract:
  We define the uniform face ideal of a simplicial complex with respect to an
ordered proper vertex colouring of the complex. This ideal is a monomial ideal
which is generally not squarefree. We show that such a monomial ideal has a
linear resolution, as do all of its powers, if and only if the colouring
satisfies a certain nesting property.
  In the case when the colouring is nested, we give a minimal cellular
resolution supported on a cubical complex. From this, we give the graded Betti
numbers in terms of the face-vector of the underlying simplicial complex.
Moreover, we explicitly describe the Boij-S\"oderberg decompositions of both
the ideal and its quotient. We also give explicit formul\ae\ for the
codimension, Krull dimension, multiplicity, projective dimension, depth, and
regularity. Further still, we describe the associated primes, and we show that
they are persistent.


title: Resonance, multiple diffusion and critical tunneling for Gaussian lasers

abstract:
  We present a detailed study of the gaussian laser propagation through a
dielectric system composed by two right angle prisms. We investigate the
transition between the spatial coherence limit, which exhibits wave-like
properties and for which the resonance phenomenon can be seen, and the
decoherence limit, which exhibits particle-like properties and for which the
multiple diffusion occurs. We also analyze the tunneling at critical angles. In
our numerical analysis, we shall use BK7 and Fused Silica prisms and a gaussian
He-Ne laser with a wavelength of 632.8 nm and beam waists of 2 mm and 200
micron.


title:
Electron emission at very low electron impact energy: experimental and
  Monte-Carlo results

abstract:
  The behaviour of electron emission under electron impact at very low energy
is of great importance in many applications such as high energy physics,
satellites, nuclear reactors, etc. However the question of the total electron
reflectivity is still in discussion. Our experimental and theoretical studies
show that the total reflectivity at very low energy is far from being an
obvious fact. Moreover, our results show that the yield is close to zero and
not equal to one for low energy incident electron.


title:
Observation of $B^0_s$-$\bar{B}^0_s$ mixing and measurement of mixing
  frequencies using semileptonic B decays

abstract:
  The $B^0_s$ and $B^0$ mixing frequencies, $\Delta m_s$ and $\Delta m_d$, are
measured using a data sample corresponding to an integrated luminosity of 1.0
fb^{-1} collected by the LHCb experiment in $pp$ collisions at a centre of mass
energy of 7 TeV during 2011. Around 1.8x10^6 candidate events are selected of
the type $B^0_{(s)} \to D^-_{(s)} \mu^+$ (+ anything), where about half are
from peaking and combinatorial backgrounds. To determine the B decay times, a
correction is required for the momentum carried by missing particles, which is
performed using a simulation-based statistical method. Associated production of
muons or mesons allows us to tag the initial-state flavour and so to resolve
oscillations due to mixing. We obtain \Delta m_s = (17.93 \pm 0.22 (stat) \pm
0.15 (syst)) ps^{-1}, \Delta m_d = (0.503 \pm 0.011 (stat) \pm 0.013 (syst))
ps^{-1}. The hypothesis of no oscillations is rejected by the equivalent of 5.8
standard deviations for $B^0_s$ and 13.0 standard deviations for $B^0$. This is
the first observation of $B^0_s$ mixing to be made using only semileptonic
decays.


title: Evolution of Cloud Storage as Cloud Computing Infrastructure Service

abstract:
  Enterprises are driving towards less cost, more availability, agility,
managed risk - all of which is accelerated towards Cloud Computing. Cloud is
not a particular product, but a way of delivering IT services that are
consumable on demand, elastic to scale up and down as needed, and follow a
pay-for-usage model. Out of the three common types of cloud computing service
models, Infrastructure as a Service (IaaS) is a service model that provides
servers, computing power, network bandwidth and Storage capacity, as a service
to their subscribers. Cloud can relate to many things but without the
fundamental storage pieces, which is provided as a service namely Cloud
Storage, none of the other applications is possible. This paper introduces
Cloud Storage, which covers the key technologies in cloud computing and Cloud
Storage, management insights about cloud computing, different types of cloud
services, driving forces of cloud computing and cloud storage, advantages and
challenges of cloud storage and concludes by pinpointing few challenges to be
addressed by the cloud storage providers.


title:
Density and Spin Linear Response of Atomic Fermi Superfluids with
  Population Imbalance in BCS-BEC Crossover

abstract:
  We present a theoretical study of the density and spin (representing the two
components) linear response of Fermi superfluids with tunable attractive
interactions and population imbalance. In both linear response theories, we
find that the fluctuations of the order parameter must be treated on equal
footing with the gauge transformations associated with the symmetries of the
Hamiltonian so that important constraints including various sum rules can be
satisfied. Both theories can be applied to the whole BCS-Bose-Einstein
condensation crossover. The spin linear responses are qualitatively different
with and without population imbalance because collective-mode effects from the
fluctuations of the order parameter survive in the presence of population
imbalance, even though the associated symmetry is not broken by the order
parameter. Since a polarized superfluid becomes unstable at low temperatures in
the weak and intermediate coupling regimes, we found that the density and spin
susceptibilities diverge as the system approaches the unstable regime, but the
emergence of phase separation preempts the divergence.


title: Carbon coating of the SPS dipole chambers

abstract:
  The Electron Multipacting (EM) phenomenon is a limiting factor for the
achievement of high luminosity in accelerators for positively charged particles
and for the performance of RF devices. At CERN, the Super Proton Synchrotron
(SPS) must be upgraded in order to feed the Large Hadron Collider (LHC) with 25
ns bunch spaced beams. At such small bunch spacing, EM may limit the
performance of the SPS and consequently that of the LHC. To mitigate this
phenomenon CERN is developing a carbon thin film coating with low Secondary
Electron Yield (SEY) to coat the internal walls of the SPS dipoles beam pipes.
This paper presents the progresses in the coating technology, the performance
of the carbon coatings and the strategy for a large scale production.


title: Proof of the Gour-Wallach conjecture

abstract:
  The absolute value of the hyperdeterminant of four qubits is a useful measure
of genuine entanglement. We prove a recent conjecture of Gour and Wallach
describing the pure maximally entangled four-qubit states with respect to this
measure.


title: On coniveau filtration of Grothendieck group of a scheme

abstract:
  In this note we consider the coniveau filtration on the Grothendieck group of
a regular separated noetherian scheme and its behavior with respect to the
multiplication and the lambda ring structure. We show that a weak
multiplicativity result can be proved. A strong compatibility result on Adams
operations is also obtained.


title: Optical helicity of interfering waves

abstract:
  Helicity is a property of light which is familiar from particle physics but
less well-known in optics. In this paper we recall the explicit form taken by
the helicity of light within classical electromagnetic theory and reflect upon
some of its remarkable characteristics. The helicity of light is related to,
but is distinct from, the spin of light. To emphasise this fact, we draw a
simple analogy between the helicity of light and electric charge and between
the spin of light and electric current. We illustrate this and other
observations by examining various superpositions of plane waves explicitly.


title: Study of SEY degradation of amorphous carbon coatings

abstract:
  Deposition of low secondary electron yield (SEY) carbon coatings by magnetron
sputtering onto the inner walls of the accelerator seems to be the most
promising solution for suppressing the electron cloud problem. However, these
coatings change their electron emission properties during long term exposure to
air. The ageing process of carbon coated samples with initial SEY of about 0.9
received from CERN is studied as a function of exposure to different
environments. It is shown that samples having the same initial SEY may age with
different rates. The SEY increase can be correlated with the surface
concentration of oxygen. Annealing of samples in air at 100-200 {\deg}C reduces
the ageing rate and even recovers previously degraded samples. The result of
annealing is reduction of the hydrogen content in the coatings by triggering
its surface segregation followed by desorption.


title: Probing the Upper Scorpius mass function in the planetary-mass regime

abstract:
  We present the results of a deep ZYJ near-infrared survey of 13.5 square
degrees in the Upper Scorpius (USco) OB association. We photometrically
selected ~100 cluster member candidates with masses in the range 30-5 Jupiters,
according to state-of-the-art evolutionary models. We identified 67 ZYJ
candidates as bona-fide members, based on complementary photometry and
astrometry. We also extracted five candidates detected with VISTA at YJ-only.
One is excluded using deep optical z-band imaging, while two are likely
non-members, and three remain as potential members. We conclude that the USco
mass function is more likely decreasing in the planetary-mass regime (although
a flat mass function cannot yet be discarded), consistent with surveys in other
regions.


title: Pre-Processing and Post-Processing in Group-Cluster Mergers

abstract:
  Galaxies in clusters are more likely to be of early type and to have lower
star formation rates than galaxies in the field. Recent observations and
simulations suggest that cluster galaxies may be `pre-processed' by group or
filament environments and that galaxies that fall into a cluster as part of a
larger group can stay coherent within the cluster for up to one orbital period
(`post-processing'). We investigate these ideas by means of a cosmological
$N$-body simulation and idealized $N$-body plus hydrodynamics simulations of a
group-cluster merger. We find that group environments can contribute
significantly to galaxy pre-processing by means of enhanced galaxy-galaxy
merger rates, removal of galaxies' hot halo gas by ram pressure stripping, and
tidal truncation of their galaxies. Tidal distortion of the group during infall
does not contribute to pre-processing. Post-processing is also shown to be
effective: galaxy-galaxy collisions are enhanced during a group's pericentric
passage within a cluster, the merger shock enhances the ram pressure on group
and cluster galaxies, and an increase in local density during the merger leads
to greater galactic tidal truncation.


title:
Bounding $\lambda_{2}$ for K\"ahler-Einstein metrics with large symmetry
  groups

abstract:
  We calculate an upper bound for the second nonzero eigenvalue of the scalar
Laplacian, $\lambda_{2}$, for toric K\"ahler-Einstein metrics in terms of the
polytope data. We give some detailed examples in complex dimensions 1, 2 and 3.
We also discuss extensions of this method to other geometries.


title:
A computational framework for infinite-dimensional Bayesian inverse
  problems. Part I: The linearized case, with application to global seismic
  inversion

abstract:
  We present a computational framework for estimating the uncertainty in the
numerical solution of linearized infinite-dimensional statistical inverse
problems. We adopt the Bayesian inference formulation: given observational data
and their uncertainty, the governing forward problem and its uncertainty, and a
prior probability distribution describing uncertainty in the parameter field,
find the posterior probability distribution over the parameter field. The prior
must be chosen appropriately in order to guarantee well-posedness of the
infinite-dimensional inverse problem and facilitate computation of the
posterior. Furthermore, straightforward discretizations may not lead to
convergent approximations of the infinite-dimensional problem. And finally,
solution of the discretized inverse problem via explicit construction of the
covariance matrix is prohibitive due to the need to solve the forward problem
as many times as there are parameters. Our computational framework builds on
the infinite-dimensional formulation proposed by Stuart (A. M. Stuart, Inverse
problems: A Bayesian perspective, Acta Numerica, 19 (2010), pp. 451-559), and
incorporates a number of components aimed at ensuring a convergent
discretization of the underlying infinite-dimensional inverse problem. The
framework additionally incorporates algorithms for manipulating the prior,
constructing a low rank approximation of the data-informed component of the
posterior covariance operator, and exploring the posterior that together ensure
scalability of the entire framework to very high parameter dimensions. We
demonstrate this computational framework on the Bayesian solution of an inverse
problem in 3D global seismic wave propagation with hundreds of thousands of
parameters.


title:
Two magnon bound state causes ultrafast thermally induced magnetisation
  switching

abstract:
  There has been much interest recently in the discovery of thermally induced
magnetisation switching, where a ferrimagnetic system can be switched
deterministically without and applied magnetic field. Experimental results
suggest that the reversal occurs due to intrinsic material properties, but so
far the microscopic mechanism responsible for reversal has not been identified.
Using computational and analytic methods we show that the switching is caused
by the excitation of two magnon bound states, the properties of which are
dependent on material factors. This discovery allows us to accurately predict
the switching behaviour and the identification of this mechanism will allow new
classes of materials to be identified or designed to use this switching in
memory devices in the THz regime.


title:
Time-domain inspiral templates for spinning compact binaries in
  quasi-circular orbits described by their orbital angular momenta

abstract:
  We present a prescription to compute the time-domain gravitational wave (GW)
polarization states associated with spinning compact binaries inspiraling along
quasi-circular orbits. We invoke the orbital angular momentum $\vek L$ rather
than its Newtonian counterpart $\vek L_{\rm N}$ to describe the binary orbits
while the two spin vectors are freely specified in an inertial frame associated
with the initial direction of the total angular momentum. We show that the use
of $\vek L$ to describe the orbits leads to additional 1.5PN order amplitude
contributions to the two GW polarization states compared to the $\vek L_{\rm
N}$-based approach and discuss few implications of our approach. Further, we
provide a plausible prescription for GW phasing based on few theoretical
considerations and which may be treated as the natural circular limit to GW
phasing for spinning compact binaries in inspiraling eccentric orbits
[Gopakumar A and Sch{\"a}fer G 2011 {\em Phys. Rev. D} {\bf 84} 124007].


title: Novel types of anti-ecloud surfaces

abstract:
  In high power RF devices for space, secondary electron emission appears as
the main parameter governing the multipactor effect and as well as the e-cloud
in large accelerators. Critical experimental activities included development of
coatings with low secondary electron emission yield (SEY) for steel (large
accelerators) and aluminium (space applications). Coatings with surface
roughness of high aspect ratio producing the so-call secondary emission
suppression effect appear as the selected strategy. In this work a detailed
study of the SEY of these technological coatings and also the experimental
deposition methods (PVD and electrochemical) are presented. The coating-design
approach selected for new low SEY coatings include rough metals (Ag, Au, Al),
rough alloys (NEG), particulated and magnetized surfaces, and also graphene
like coatings. It was found that surface roughness also mitigate the SEY
deterioration due to aging processes.


title: Nonlinear mechanics of thermoreversibly associating dendrimer glasses

abstract:
  We model the mechanics of associating trivalent dendrimer network glasses
with a focus on their energy dissipation properties. Various combinations of
sticky bond (SB) strength and kinetics are employed. The toughness
(work-to-fracture) of these systems displays a surprising deformation-protocol
dependence; different association parameters optimize different properties. In
particular, "strong, slow" SBs optimize strength, while "weak, fast" SBs
optimize ductility via self-healing during deformation. We relate these
observations to breaking, reformation, and partner-switching of SBs during
deformation. These studies point the way to creating associating-polymer
network glasses with tailorable mechanical properties.


title: Irreducible lattices, invariant means, and commensurating actions

abstract:
  We study rigidity properties of lattices in terms of invariant means and
commensurating actions (or actions on CAT(0) cube complexes). We notably study
Property FM for groups, namely that any action on a discrete set with an
invariant mean has a finite orbit.


title: Inferring HIV escape rates from multi-locus genotype data

abstract:
  Cytotoxic T-lymphocytes (CTLs) recognize viral protein fragments displayed by
major histocompatibility complex (MHC) molecules on the surface of virally
infected cells and generate an anti-viral response that can kill the infected
cells. Virus variants whose protein fragments are not efficiently presented on
infected cells or whose fragments are presented but not recognized by CTLs
therefore have a competitive advantage and spread rapidly through the
population. We present a method that allows a more robust estimation of these
escape rates from serially sampled sequence data. The proposed method accounts
for competition between multiple escapes by explicitly modeling the
accumulation of escape mutations and the stochastic effects of rare multiple
mutants. Applying our method to serially sampled HIV sequence data, we estimate
rates of HIV escape that are substantially larger than those previously
reported. The method can be extended to complex escapes that require
compensatory mutations. We expect our method to be applicable in other contexts
such as cancer evolution where time series data is also available.


title: The solar-type eclipsing binary system LL Aquarii

abstract:
  The eclipsing binary LL Aqr consists of two late-type stars in an eccentric
orbit with a period of 20.17 d. We use an extensive light curve from the
SuperWASP survey augmented by published radial velocities and UBV light curves
to measure the physical properties of the system. The primary star has a mass
of 1.167 +/- 0.009 Msun and a radius of 1.305 +/- 0.007 Rsun. The secondary
star is an analogue of the Sun, with a mass and radius of 1.014 +/- 0.006 Msun
and 0.990 +/- 0.008 Rsun respectively. The system shows no signs of stellar
activity: the upper limit on spot-induced rotational modulation is 3 mmag, it
is slowly rotating, has not been detected at X-ray wavelengths, and the calcium
H and K lines exhibit no emission. Theoretical stellar models provide a good
match to its properties for a sub-solar metal abundance of Z = 0.008 and an age
of 2.5 Gyr. Most low-mass eclipsing binary systems are found to have radii
larger than expected from theoretical predictions, blamed on tidally-enhanced
magnetic fields in these short-period systems. The properties of LL Aqr support
this scenario: it exhibits negligible tidal effects, shows no signs of magnetic
activity, and matches theoretical models well.


title: Asset Allocation under the Basel Accord Risk Measures

abstract:
  Financial institutions are currently required to meet more stringent capital
requirements than they were before the recent financial crisis; in particular,
the capital requirement for a large bank's trading book under the Basel 2.5
Accord more than doubles that under the Basel II Accord. The significant
increase in capital requirements renders it necessary for banks to take into
account the constraint of capital requirement when they make asset allocation
decisions. In this paper, we propose a new asset allocation model that
incorporates the regulatory capital requirements under both the Basel 2.5
Accord, which is currently in effect, and the Basel III Accord, which was
recently proposed and is currently under discussion. We propose an unified
algorithm based on the alternating direction augmented Lagrangian method to
solve the model; we also establish the first-order optimality of the limit
points of the sequence generated by the algorithm under some mild conditions.
The algorithm is simple and easy to implement; each step of the algorithm
consists of solving convex quadratic programming or one-dimensional
subproblems. Numerical experiments on simulated and real market data show that
the algorithm compares favorably with other existing methods, especially in
cases in which the model is non-convex.


title: NMR evidence for spin fluctuations in the bilayer nickelate La3Ni2O6

abstract:
  We report nuclear magnetic resonance data in the bilayer nickelate La3Ni2O6.
This material belongs to a family of low valence nickel oxides with square
planar coordination of the Ni ions and is isoelectronic to the high temperature
superconducting cuprates. Although the three layer nickelate compound exhibits
a spin-state transition accompanied by antiferromagnetic order, the bilayer
material shows no phase transition. The NMR data in the bilayer La3Ni2O6 reveal
the presence of antiferromagnetic spin fluctuations down to 5K that are
surprisingly similar to those present in the magnetically ordered trilayer
La4Ni3O8, suggesting a similar electronic structure in the paramagnetic phase
of both compounds.


title:
Classical and Quantum Reissner-Nordstr\"om Black Hole Thermodynamics and
  first order Phase Transition

abstract:
  First we consider CRNBH metric which is obtained by solving Einstein-Maxwell
metric equation for a point electric charge $e$ inside of a spherical static
body with mass $M$. It has 2 interior and exterior horizons. Using
Bekenestein-Hawking entropy theorem we calculate interior and exterior entropy,
temperature, Gibbs free energy and heat capacity at constant electric charge.
We calculate first derivative of the Gibbs free energy with respect to
temperature which become a singular function having a singularity at critical
point with corresponding temperature $T_c=\frac{1}{24\pi \sqrt{3}|e|}.$ Hence
we clime first order phase transition is happened there. Temperature same as
Gibbs free energy takes absolutely positive (negative) values on the exterior
(interior) horizon. The Gibbs free energy takes two different positive values
synchronously for $0<T<T_c$ but not for negative values which means the system
is made from two subsystem. For negative temperatures entropy reaches to zero
value at $T\to-\infty$ and so takes Bose-Einstein condensation single state.
Entropy increases monotonically in case $0<T<T_c$. Regarding results of the
work presented at Ref. \citep{Bob01} we calculate again the mentioned
thermodynamical variables for remnant stable final state of evaporating QRNBH
and obtained results same as one in case of the CRNBH. Finally, we solve mass
loss equation of QRNBH against advance Eddington-Finkelstein time coordinate
and derive luminosity function. We obtain switching off of QRNBH evaporation
before than the mass completely vanishes. It reaches to a could Lukewarm type
of RN black hole which its final remnant mass is $m_{final}=|e|$ in geometrical
units. Its temperature and luminosity vanish but not in Schwarzschild case of
evaporation. Our calculations can be takes some acceptable statements about
information loss paradox .


title: A DNC function that computes no effectively bi-immune set

abstract:
  In Diagonally Non-Computable Functions and Bi-Immunity, Carl Jockusch and
Andrew Lewis proved that every DNC function computes a bi-immune set. They
asked whether every DNC function computes an effectively bi-immune set. We
construct a DNC function that computes no effectively bi-immune set, thereby
answering their question in the negative.


title:
On the conformal structure of the extremal Reissner-Nordstr\"om
  spacetime

abstract:
  We analyse various conformal properties of the extremal Reissner-Nordstr\"om
spacetime. In particular, we obtain conformal representations of the
neighbourhoods of spatial infinity, timelike infinity and the cylindrical end
---the so-called cylinders at spatial infinity and at the horizon,
respectively--- which are regular with respect to the conformal Einstein field
equations and their associated initial data sets. We discuss possible
implications of these constructions for the propagation of test fields and
non-linear perturbations of the gravitational field close to the horizon.


title:
Confinement of ultracold atoms in a Laguerre-Gaussian laser beam created
  with diffractive optics

abstract:
  We report 2D confinement of Rb 87 atoms in a Laguerre-Gaussian laser beam.
Changing of the sign of the detuning from the atomic resonance dramatically
alters the geometry of the confinement. With the laser detuned to the blue, the
atoms are confined to the dark, central node of the Laguerre-Gaussian laser
mode. This trapping method leads to low ac Stark shifts to the atomic levels.
Alternatively, by detuning the laser to the red of the resonance, we confine
atoms to the high intensity outer ring in a multiply-connected, toroidal
configuration. We model the confined atoms to determine azimuthal intensity
variations of the trapping laser, caused by slight misalignments of the
Laguerre-Gaussian mode generating optics.


title:
Convolution-type derivatives, hitting-times of subordinators and
  time-changed $C_0$-semigroups

abstract:
  In this paper we will take under consideration subordinators and their
inverse processes (hitting-times). We will present in general the governing
equations of such processes by means of convolution-type integro-differential
operators similar to the fractional derivatives. Furthermore we will discuss
the concept of time-changed $C_0$-semigroup in case the time-change is
performed by means of the hitting-time of a subordinator. We will show that
such time-change give rise to bounded linear operators not preserving the
semigroup property and we will present their governing equations by using again
integro-differential operators. Such operators are non-local and therefore we
will investigate the presence of long-range dependence.


title:
A simple model of filtration and macromolecule transport through
  microvascular walls

abstract:
  Multiple Sclerosis (MS) is a disorder that usually appears in adults in their
thirties. It has a prevalence that ranges between 2 and 150 per 100 000.
Epidemiological studies of MS have provided hints on possible causes for the
disease ranging from genetic, environmental and infectious factors to other
factors of vascular origin. Despite the tremendous effort spent in the last few
years, none of the hypotheses formulated so far has gained wide acceptance and
the causes of the disease remain unknown. From a clinical point of view, a high
correlation has been recently observed between MS and Chronic Cerebro-Spinal
Venous Insufficiency (CCSVI) in a statistically significant number of patients.
In this pathological situation CCSVI may induce alterations of blood pressure
in brain microvessels, thereby perturbing the exchange of small hydrophilic
molecules between the blood and the external cells. In the presence of large
pressure alterations it cannot be excluded also the leakage of macromolecules
that otherwise would not cross the vessel wall. All these disorders may trigger
immune defenses with the destruction of myelin as a side effect. In the present
work we investigate the role of perturbed blood pressure in brain microvessels
as driving force for an altered exchange of small hydrophilic solutes and
leakage of macromolecules into the interstitial fluid. With a simplified, yet
realistic, model we obtain closed-form steady-state solutions for fluid flow
and solute transport across the microvessel wall. Finally, we use these results
(i) to interpret experimental data available in the literature and (ii) to
carry out a preliminary analysis of the disorder in the exchange processes
triggered by an increase of blood pressure, thereby relating our preliminary
results to the hypothesised vascular connection to MS.


title:
A novel picture for charge transport interpretation in epitaxial
  manganite thin films

abstract:
  Transport characterizations of epitaxial La0.7Sr0.3MnO3 thin films in the
thickness range 5-40 nm and 25-410 K temperature interval have been accurately
collected. We show that taking into account polaronic effects allows to achieve
the best ever fitting of the transport curves in the whole temperature range.
The Current Carriers Density Collapse picture accurately accounts for the
properties variation across the metal-insulator-transition. The electron-phonon
coupling parameter estimations are in a good agreement with theoretical
predictions. The results promote a clear and straightforward quantitative
description of the manganite films involved in charge transport device
applications.


title:
Analysis of Molecular Hydrogen Absorption toward QSO B0642-5038 for a
  Varying Proton-to-Electron Mass Ratio

abstract:
  Rovibronic molecular hydrogen (H$_2$) transitions at redshift $z_{\rm abs}
\simeq 2.659$ towards the background quasar B0642$-$5038 are examined for a
possible cosmological variation in the proton-to-electron mass ratio, $\mu$. We
utilise an archival spectrum from the Very Large Telescope/Ultraviolet and
Visual Echelle Spectrograph with a signal-to-noise ratio of $\sim$35 per
2.5-km$\,$s$^{-1}$ pixel at the observed H$_2$ wavelengths (335--410 nm). Some
111 H$_2$ transitions in the Lyman and Werner bands have been identified in the
damped Lyman $\alpha$ system for which a kinetic gas temperature of $\sim$84 K
and a molecular fraction $\log f = -2.18\pm0.08$ is determined. The H$_2$
absorption lines are included in a comprehensive fitting method, which allows
us to extract a constraint on a variation of the proton-electron mass ratio,
$\Delta\mu/\mu$, from all transitions at once. We obtain $\Delta\mu/\mu = (17.1
\pm 4.5_{\rm stat} \pm3.7_{\rm sys})\times10^{-6}$. However, we find evidence
that this measurement has been affected by wavelength miscalibration errors
recently identified in UVES. A correction based on observations of objects with
solar-like spectra gives a smaller $\Delta\mu/\mu$ value and contributes to a
larger systematic uncertainty: $\Delta\mu/\mu = (12.7 \pm 4.5_{\rm stat}
\pm4.2_{\rm sys})\times10^{-6}$.


title: Principles of an Atomtronic Battery

abstract:
  An asymmetric atom trap is investigated as a means to implement a "battery"
that supplies ultracold atoms to an atomtronic circuit. The battery model is
derived from a scheme for continuous loading of a non-dissipative atom trap
proposed by Roos et al.(Europhysics Letters V61, 187 (2003)). The trap is
defined by longitudinal and transverse trap frequencies and corresponding trap
energy heights. The battery's ability to supply power to a load is evaluated as
a function of an input atom flux and power. For given trap parameters and input
flux the battery is shown to have a resonantly optimum value of input power.
The battery behavior can be cast in terms of an equivalent circuit model;
specifically, for fixed input flux and power the battery is modeled in terms of
a Th\'{e}venin equivalent chemical potential and internal resistance. The
internal resistance establishes the maximum power that can be supplied to a
circuit, the heat that will be generated by the battery, and that noise will be
imposed on the circuit. We argue that any means of implementing a battery for
atomtronics can be represented by a Th\'{e}venin equivalent and that its
performance will likewise be determined by an internal resistance.


title: Infrared composition of the Large Magellanic Cloud

abstract:
  The evolution of galaxies and the history of star formation in the Universe
are among the most important topics in today's astrophysics. Especially, the
role of small, irregular galaxies in the star-formation history of the Universe
is not yet clear. Using the data from the AKARI IRC survey of the Large
Magellanic Cloud at 3.2, 7, 11, 15, and 24 {\mu}m wavelengths, i.e., at the
mid- and near-infrared, we have constructed a multiwavelength catalog
containing data from a cross-correlation with a number of other databases at
different wavelengths. We present the separation of different classes of stars
in the LMC in color-color, and color-magnitude, diagrams, and analyze their
contribution to the total LMC flux, related to point sources at different
infrared wavelengths.


title:
A comparison of the Higgs sectors of the CMSSM and NMSSM for a 126 GeV
  Higgs boson

abstract:
  The recent discovery of a Higgs-like boson at the LHC with a mass of 126 GeV
has revived the interest in supersymmetric models, which predicted a Higgs
boson mass below 130 GeV long before its discovery. We compare systematically
the allowed parameter space in the constrained Minimal Supersymmetric Standard
Model (CMSSM) and the Next-to-Minimal Supersymmetric Model (NMSSM) by
minimizing the chi^2 function with respect to all known constraints from
accelerators and cosmology using GUT scale parameters. For the CMSSM the Higgs
boson mass at tree level is below the Z^0 boson mass and large radiative
corrections are needed to obtain a Higgs boson mass of 126 GeV, which requires
stop squark masses in the multi-TeV range. In contrast, for the NMSSM light
stop quarks are allowed, since in the NMSSM at tree level the Higgs boson mass
can be above the Z^0 boson mass from mixing with the additional singlet Higgs
boson. Predictions for the scalar boson masses are given in both models with
emphasis on the unique signatures of the NMSSM, where the heaviest scalar Higgs
boson decays in the two lighter scalar Higgs bosons with a significant
branching ratio, in which case one should observe double Higgs boson production
at the LHC. Such a signal is strongly suppressed in the CMSSM. In addition,
since the LSP is higgsino-like, Higgs boson decays into LSPs can be
appreciable, thus leading to invisible Higgs decays.


title: Geometric median and robust estimation in Banach spaces

abstract:
  In many real-world applications, collected data are contaminated by noise
with heavy-tailed distribution and might contain outliers of large magnitude.
In this situation, it is necessary to apply methods which produce reliable
outcomes even if the input contains corrupted measurements. We describe a
general method which allows one to obtain estimators with tight concentration
around the true parameter of interest taking values in a Banach space.
Suggested construction relies on the fact that the geometric median of a
collection of independent "weakly concentrated" estimators satisfies a much
stronger deviation bound than each individual element in the collection. Our
approach is illustrated through several examples, including sparse linear
regression and low-rank matrix recovery problems.


title: Shear banding in time-dependent flows of polymers and wormlike micelles

abstract:
  We study theoretically the formation of shear bands in time-dependent flows
of polymeric and wormlike micellar surfactant fluids, focussing on the
protocols of step shear stress, step shear strain (or in practice a rapid
strain ramp), and shear startup, which are commonly studied experimentally. For
each protocol we perform a linear stability analysis to provide a
fluid-universal criterion for the onset of shear banding, following our recent
Letter [Phys. Rev. Lett. 110 (2013) 086001]. In each case this criterion
depends only on the shape of the experimentally measured rheological response
function for that protocol, independent of the constitutive properties of the
material in question. (Therefore our criteria in fact concern all complex
fluids and not just the polymeric ones of interest here. A separate manuscript
[in preparation] will explore them in a broad class of disordered soft glassy
materials including foams, dense emulsions, dense colloids, and microgel bead
suspensions.) An important prediction is that pronounced banding can arise
transiently in each of these protocols, even in fluids for which the underlying
constitutive curve of stress as a function of strain-rate is monotonic and a
steadily flowing state is accordingly unbanded. For each protocol we provide
numerical results in the rolie-poly and Giesekus models that support our
predictions. We comment on the ability of the rolie-poly model to capture the
observed experimental phenomenology, and on the failure of the Giesekus model.


title: Secret-key generation from wireless channels: Mind the reflections

abstract:
  Secret-key generation in a wireless environment exploiting the randomness and
reciprocity of the channel gains is considered. A new channel model is proposed
which takes into account the effect of reflections (or re-radiations) from
receive antenna elements, thus capturing an physical property of practical
antennas. It turns out that the reflections have a deteriorating effect on the
achievable secret-key rate between the legitimate nodes at high
signal-to-noise-power-ratio (SNR). The insights provide guidelines in the
design and operation of communication systems using the properties of the
wireless channel to prevent eavesdropping.


title: Bifurcations analysis of turbulent energy cascade

abstract:
  This note studies the mechanism of turbulent energy cascade through an
opportune bifurcations analysis of the Navier--Stokes equations, and furnishes
explanations on the more significant characteristics of the turbulence. A
statistical bifurcations property of the Navier--Stokes equations in fully
developed turbulence is proposed, and a spatial representation of the
bifurcations is presented, which is based on a proper definition of the fixed
points of the velocity field. The analysis first shows that the local
deformation can be much more rapid than the fluid state variables, then
explains the mechanism of energy cascade through the aforementioned property of
the bifurcations, and gives reasonable argumentation of the fact that the
bifurcations cascade can be expressed in terms of length scales. Furthermore,
the study analyzes the characteristic length scales at the transition through
global properties of the bifurcations, and estimates the order of magnitude of
the critical Taylor--scale Reynolds number and the number of bifurcations at
the onset of turbulence.


title: Functional calculus for generators of symmetric contraction semigroups

abstract:
  We prove that every generator of a symmetric contraction semigroup on a
$\sigma$-finite measure space admits, for $1<p<\infty$, a H\"ormander-type
holomorphic functional calculus on $L^p$ in the sector of angle
$\phi^*_p=\arcsin|1-2/p|$. The obtained angle is optimal.


title:
Single-photon transport in a one dimentional waveguide coupling to a
  hybrid atom-optomechanical system

abstract:
  We explore theoretically the single-photon transport in a single-mode
waveguide that is coupled to a hybrid atom-optomechanical system in a strong
optomechanical coupling regime. Using a full quantum real-space approach,
transmission and reflection coefficients of the propagating single-photon in
the waveguide are ob- tained. The influences of atom-cavity detuning and the
dissipation of atom on the transport are also studied. Intriguingly, the
obtained spectral features can reveal the strong light-matter interaction in
this hybrid system.


title:
Measurement of the $C\P$ asymmetry in $B^+ \rightarrow K^+ \mu^+ \mu^-$
  decays

abstract:
  A measurement of the $C\P$ asymmetry in $B^+ \rightarrow K^+ \mu^+ \mu^-$
decays is presented using $pp$ collision data, corresponding to an integrated
luminosity of 1.0${\,fb}^{-1}$, recorded by the LHCb experiment during 2011 at
a centre-of-mass energy of 7 TeV. The measurement is performed in seven bins of
$\mu^+ \mu^-$ invariant mass squared in the range
${0.05<q^{2}<22.00{\mathrm{GeV^2/}c^4}}$, excluding the ${J/\psi}$ and
$\psi{(2S)}$ resonance regions. Production and detection asymmetries are
corrected for using the $B^+ \rightarrow J/\psi K^+$ decay as a control mode.
Averaged over all the bins, the $C\P$ asymmetry is found to be ${{\cal A}_{C\P}
= 0.000\pm 0.033{(stat.)} \pm0.005 {(syst.)} \pm 0.007{}(J/\psi K^+)}$, where
the third uncertainty is due to the $C\P$ asymmetry of the control mode. This
is consistent with the Standard Model prediction.


title: Charge without charge in quarks

abstract:
  With appropriate gauge transformations, field can replace electric charge in
quarks. Classical quarks, in a necessary non-gauge invariant formulation, are
used for illustration, bringing to the fore the limitations of the usual
electric charge densities for single particles in Coulomb equations. The
results are encouraging; the solutions for the Coulomb potentials apply
individually to each quark in a shell structure. A remarkably simple relation
emerges between the Coulomb and weak potentials.


title: The Gravity Tunnel in a Non-Uniform Earth

abstract:
  How long does it take to fall down a tunnel through the center of the Earth
to the other side? Assuming a uniformly dense Earth, it would take 42 minutes,
but this assumption has not been validated. This paper examines the gravity
tunnel without this restriction, using the internal structure of the Earth as
ascertained by seismic data, and the dynamics are solved numerically. The time
taken to fall along the diameter is found to be 38 rather than 42 minutes. The
time taken to fall along a straight line between any two points is no longer
independent of distance, but interpolates between 42 minutes for short trips
and 38 minutes for long trips. The brachistochrone path (minimizing the fall
time between any two points) is similar to the uniform density solution, but
tends to reach a greater maximum depth and takes less time to traverse.
Although the assumption of uniform density works well in many cases, the
simpler assumption of a constant gravitational field serves as a better
approximation to the true results.


title:
Performance and Optimization Abstractions for Large Scale Heterogeneous
  Systems in the Cactus/Chemora Framework

abstract:
  We describe a set of lower-level abstractions to improve performance on
modern large scale heterogeneous systems. These provide portable access to
system- and hardware-dependent features, automatically apply dynamic
optimizations at run time, and target stencil-based codes used in finite
differencing, finite volume, or block-structured adaptive mesh refinement
codes.
  These abstractions include a novel data structure to manage refinement
information for block-structured adaptive mesh refinement, an iterator
mechanism to efficiently traverse multi-dimensional arrays in stencil-based
codes, and a portable API and implementation for explicit SIMD vectorization.
  These abstractions can either be employed manually, or be targeted by
automated code generation, or be used via support libraries by compilers during
code generation. The implementations described below are available in the
Cactus framework, and are used e.g. in the Einstein Toolkit for relativistic
astrophysics simulations.


title: Installing of cosmological constant

abstract:
  An artificial scale of observable cosmological constant is dynamically
related to its natural bare value due to an installation of relevant coherent
state for the inflationary field in a finite volume of early Universe, because
of exponential suppression of probability to find the state with zero number of
quanta. Homogeneous quantum fluctuations of the field actually put hard
constraints on the total amount of inflation.


title:
The moduli space of maps with crosscaps: the relative signs of the
  natural automorphisms

abstract:
  Just as a symmetric surface with separating fixed locus halves into two
oriented bordered surfaces, an arbitrary symmetric surface halves into two
oriented symmetric half-surfaces, i.e. surfaces with crosscaps. Motivated in
part by the string theory view of real Gromov-Witten invariants, we previously
introduced moduli spaces of maps from surfaces with crosscaps, developed the
relevant Fredholm theory, and resolved the orientability problem in this
setting. In this paper, we determine the relative signs of the automorphisms of
these moduli spaces induced by interchanges of boundary components of the
domain and by the anti-symplectic involution on the target manifold, without
any global assumptions on the latter. As immediate applications, we describe
sufficient conditions for the moduli spaces of real genus 1 maps and for real
maps with separating fixed locus to be orientable; we treat the general genus
2+ case in a separate paper. Our sign computations also lead to an extension of
recent Floer-theoretic applications of anti-symplectic involutions and to a
related reformulation of these results in a more natural way.


title:
The inverse problem for universal deformation rings and the special
  linear group

abstract:
  We show that every complete noetherian local commutative ring R with residue
field k can be realized as a universal deformation ring of a continuous linear
representation of a profinite group. More specifically, R is the universal
deformation ring of the natural representation of SL_n(R) in SL_n(k), provided
that n is at least 4. We also check for which R an analogous result is true in
case n=2 and n=3.


title: Orientability in real Gromov-Witten theory

abstract:
  The orientability problem in real Gromov-Witten theory is one of the
fundamental hurdles to enumerating real curves. In this paper, we describe
topological conditions on the target manifold which ensure that the
uncompactified moduli spaces of real maps are orientable for all genera of and
for all types of involutions on the domain. In contrast to the typical
approaches to this problem, we do not compute the signs of any diffeomorphisms,
but instead compare them. Many projective complete intersections, including the
renowned quintic threefold, satisfy our topological conditions. Our main result
yields real Gromov-Witten invariants of arbitrary genus for real symplectic
manifolds that satisfy these conditions and have empty real locus and
illustrates the significance of previously introduced moduli spaces of maps
with crosscaps. We also apply it to study the orientability of the moduli
spaces of real Hurwitz covers.


title:
Time-resolving electron-core dynamics during strong field ionization in
  circularly polarized fields

abstract:
  Electron-core interactions play a key role in strong-field ionization and the
formation of photoelectron spectra. We analyse the temporal dynamics of strong
field ionization associated with these interactions using the time-dependent
analytical R-matrix (ARM) method, developed in our previous work [J. Kaushal
and O. Smirnova, Phys. Rev. A 88, 013421 (2013)]. The approach is fully quantum
but includes the concept of trajectories. However, the trajectories are not
classical in the sense that they have both real and imaginary components all
the way to the detector. We show that the imaginary parts of these
trajectories, which are usually ignored, have a clear physical meaning and are
crucial for the correct description of electron-core interactions after
ionization. In particular, they give rise to electron deceleration, as well as
dynamics associated with electron recapture and release. Our approach is
analytical and time-dependent, and allows one to gain access to the electron
energy distribution and ionization yield as a function of time. Thus we can
also rigorously answer the question: when is ionization completed?


title: A family of rotation numbers for discrete random dynamics on the circle

abstract:
  We revisit the problem of well-defining rotation numbers for discrete random
dynamical systems on the circle. We show that, contrasting with deterministic
systems, the topological (i.e. based on Poincar\'{e} lifts) approach does
depend on the choice of lifts (e.g. continuously for nonatomic randomness).
Furthermore, the winding orbit rotation number does not agree with the
topological rotation number. Existence and conversion formulae between these
distinct numbers are presented. Finally, we prove a sampling in time theorem
which recover the rotation number of continuous Stratonovich stochastic
dynamical systems on $S^1$ out of its time discretisation of the flow.


title: Dirac equation on coordinate dependent noncommutative space-time

abstract:
  We consider the consistent deformation of the relativistic quantum mechanics
introducing the noncommutativity of the space-time and preserving the Lorentz
symmetry. The relativistic wave equation describing the spinning particle on
coordinate dependent noncommutative space-time (noncommutative Dirac equation)
is proposed. The fundamental properties of this equation, like the Lorentz
covariance and the continuity equation for the probability density are
verified. To this end using the properties of the star product we derive the
corresponding probability current density and prove its conservation. The
energy-momentum tensor for the free noncommutative spinor field is calculated.
We solve the free noncommutative Dirac equation and show that the standard
energy-momentum dispersion relation remains valid in the noncommutative case.


title:
An $O^*(1.0821^n)$-Time Algorithm for Computing Maximum Independent Set
  in Graphs with Bounded Degree 3

abstract:
  We give an $O^*(1.0821^n)$-time, polynomial space algorithm for computing
Maximum Independent Set in graphs with bounded degree 3. This improves all the
previous running time bounds known for the problem.


title: Bimanual proprioception: are two hands better than one?

abstract:
  Information about the position of an object that is held in both hands, such
as a golf club or a tennis racquet, is transmitted to the human central nervous
system from peripheral sensors in both left and right arms. How does the brain
combine these two sources of information? Using a robot to move participant's
passive limbs, we performed psychophysical estimates of proprioceptive function
for each limb independently, and again when subjects grasped the robot handle
with both arms. We compared empirical estimates of bimanual proprioception to
several models from the sensory integration literature: some that propose a
combination of signals from the left and right arms (such as a Bayesian
maximum-likelihood estimate), and some that propose using unimanual signals
alone. Our results are consistent with the hypothesis that the nervous system
both has knowledge of, and uses the limb with the best proprioceptive acuity
for bimanual proprioception. Surprisingly, a Bayesian model that postulates
optimal combination of sensory signals could not predict empirically observed
bimanual acuity. These findings suggest that while the central nervous system
seems to have information about the relative sensory acuity of each limb, it
uses this information in a rather rudimentary fashion, essentially ignoring
information from the less reliable limb.


title: GLIMPSE: Accurate 3D weak lensing reconstructions using sparsity

abstract:
  We present GLIMPSE - Gravitational Lensing Inversion and MaPping with Sparse
Estimators - a new algorithm to generate density reconstructions in three
dimensions from photometric weak lensing measurements. This is an extension of
earlier work in one dimension aimed at applying compressive sensing theory to
the inversion of gravitational lensing measurements to recover 3D density maps.
Using the assumption that the density can be represented sparsely in our chosen
basis - 2D transverse wavelets and 1D line of sight dirac functions - we show
that clusters of galaxies can be identified and accurately localised and
characterised using this method. Throughout, we use simulated data consistent
with the quality currently attainable in large surveys. We present a thorough
statistical analysis of the errors and biases in both the redshifts of detected
structures and their amplitudes. The GLIMPSE method is able to produce
reconstructions at significantly higher resolution than the input data; in this
paper we show reconstructions with 6x finer redshift resolution than the shear
data. Considering cluster simulations with 0.05 <= z <= 0.75 and 3e13/h Msun <=
Mvir <= 1e15/h Msun, we show that the redshift extent of detected peaks is
typically 1-2 pixels, or Dz <~ 0.07, and that we are able to recover an
unbiased estimator of the redshift of a detected cluster by considering many
realisations of the noise. We also recover an accurate estimator of the mass,
that is largely unbiased when the redshift is known, and whose bias is
constrained to <~ 5% in the majority of our simulations when the estimated
redshift is taken to be the true redshift. This shows a substantial improvement
over earlier 3D inversion methods, which showed redshift smearing with a
typical standard deviation of 0.2-0.3, a significant damping of the amplitude
of the peaks detected, and a bias in the detected redshift.


title:
Barrierless Electronic Relaxation in Solution: An analytically solvable
  model with arbitrary coupling

abstract:
  In our recent publication, we have proposed an analytical method for solving
the problem of electronic relaxation in solution, modeled by a particle
undergoing diffusive motion under the influence of two arbitrary potentials and
the coupling between the two potentials was assumed to be localized at one
point. In this paper we have extended our work to deal with the case of
delocalized coupling between two potentials. The average and long term rate
constant for delocalized coupling is presented.


title:
An entropy admissible time splitting scheme for a conservation law model
  of manufacturing system

abstract:
  This paper deals with a splitting method applied to a conservation law model
of manufacturing system incorporating yield loss. A splitting scheme has been
proposed. The yield loss term is treated by solving implicitly an ordinary
differential equation and the hyperbolic part is approximated by a finite
volume scheme. Bounded variation stability has been studied. Due to yield loss,
proposed scheme is total variation bounded. The convergence of the numerical
solution towards entropy solution (in the Kruzkov sense) is proved. Numerical
experiments are presented to demonstrate the performance of the scheme.


title:
Impurity effect and suppression to superconductivity in
  Na(Fe$_{0.97-x}$Co$_{0.03}$T$_x$)As (T=Cu, Mn)

abstract:
  We report the successful growth and the impurity scattering effect of single
crystals of Na(Fe$_{0.97-x}$Co$_{0.03}$T$_x$)As (T=Cu, Mn). The temperature
dependence of DC magnetization at high magnetic fields is measured for
different concentrations of Cu and Mn. Detailed analysis based on the
Curie-Weiss law indicates that the Cu doping weakens the average magnetic
moments, while doping Mn enhances the local magnetic moments greatly,
suggesting that the former may be non- or very weak magnetic impurities, and
the latter give rise to magnetic impurities. However, it is found that both
doping Cu and Mn will enhance the residual resistivity and suppress the
superconductivity at the same rate in the low doping region, being consistent
with the prediction of the S$^{\pm}$ model. For the Cu-doped system, the
superconductivity is suppressed completely at a residual resistivity $\rho_0$ =
0.87 m$\Omega$ cm at which a strong localization effect is observed. However,
in the case of Mn doping, the behavior of suppression to \emph{T}$_{c}$ changes
from a fast speed to a slow one and keeps superconductive even up to a residual
resistivity of 2.86 m$\Omega$ cm. Clearly the magnetic Mn impurities are even
not as detrimental as the non- or very weak magnetic Cu impurities to
superconductivity in the high doping regime.


title:
Cosmic-ray spectral anomaly at GeV-TeV energies as due to
  re-acceleration by weak shocks in the Galaxy

abstract:
  Recent cosmic-ray measurements by the ATIC, CREAM and PAMELA experiments have
found an apparent hardening of the energy spectrum at TeV energies. Although
the origin of the hardening is not clearly understood, possible explanations
include hardening in the cosmic-ray source spectrum, changes in the cosmic-ray
propagation properties in the Galaxy and the effect of nearby sources. In this
contribution, we propose that the spectral anomaly might be an effect of
re-acceleration of cosmic rays by weak shocks in the Galaxy. After acceleration
by strong supernova remnant shock waves, cosmic rays undergo diffusive
propagation through the Galaxy. During the propagation, cosmic rays may again
encounter expanding supernova remnant shock waves, and get re-accelerated. As
the probability of encountering old supernova remnants is expected to be larger
than the young ones due to their bigger size, re-acceleration is expected to be
produced mainly by weaker shocks. Since weaker shocks generate a softer
particle spectrum, the resulting re-accelerated component will have a spectrum
steeper than the initial cosmic-ray source spectrum produced by strong shocks.
For a reasonable set of model parameters, it is shown that such re-accelerated
component can dominate the GeV energy region while the non-reaccelerated
component dominates at higher energies, explaining the observed GeV-TeV
spectral anomaly.


title: The Performance of Paxos and Fast Paxos

abstract:
  Paxos and Fast Paxos are optimal consensus algorithms that are simple and
elegant, while suitable for efficient implementation. In this paper, we compare
the performance of both algorithms in failure-free and failure-prone runs using
Treplica, a general replication toolkit that implements these algorithms in a
modular and efficient manner. We have found that Paxos outperforms Fast Paxos
for small number of replicas and that collisions are not the cause of this
performance difference.


title:
Invariances of random fields paths, with applications in Gaussian
  Process Regression

abstract:
  We study pathwise invariances of centred random fields that can be controlled
through the covariance. A result involving composition operators is obtained in
second-order settings, and we show that various path properties including
additivity boil down to invariances of the covariance kernel. These results are
extended to a broader class of operators in the Gaussian case, via the Lo\`eve
isometry. Several covariance-driven pathwise invariances are illustrated,
including fields with symmetric paths, centred paths, harmonic paths, or sparse
paths. The proposed approach delivers a number of promising results and
perspectives in Gaussian process regression.


title:
Filter Induced Bias in Ly{\alpha} Emitter Surveys: A Comparison Between
  Standard and Tunable Filters. Gran Telescopio Canarias Preliminary Results

abstract:
  Lyman-alpha emitter (LAE) surveys have successfully used the excess in a
narrow-band filter compared to a nearby broad-band image to find candidates.
However, the odd spectral energy distribution (SED) of LAEs combined with the
instrumental profile have important effects on the properties of the candidate
samples extracted from these surveys. We investigate the effect of the bandpass
width and the transmission profile of the narrow-band filters used for
extracting LAE candidates at redshifts z ~ 6.5 through Monte Carlo simulations,
and we present pilot observations to test the performance of tunable filters to
find LAEs and other emission-line candidates. We compare the samples obtained
using a narrow ideal-rectangular-filter, the Subaru NB921 narrow-band filter,
and sweeping across a wavelength range using the ultra-narrow-band tunable
filters of the instrument OSIRIS, installed at the 10.4m Gran Telescopio
Canarias. We use this instrument for extracting LAE candidates from a small set
of real observations. Broad-band data from the Subaru, HST and Spitzer
databases were used for fiting SEDs to calculate photometric redshifts and to
identify interlopers. Narrow-band surveys are very efficient to find LAEs in
large sky areas, but the samples obtained are not evenly distributed in
redshift along the filter bandpass, and the number of LAEs with equivalent
widths < 60 angstroms can be underestimated. These biased results do not appear
in samples obtained using ultra-narrow-band tunable filters. However, the field
size of tunable filters is restricted because of the variation of the effective
wavelength across the image. Thus narrow-band and ultra-narrow-band surveys are
complementary strategies to investigate high-redshift LAEs.


title:
Classification of positive solutions of heat equation with supercritical
  absorption

abstract:
  Let $q\geq 1+\frac{2}{N}$. We prove that any positive solution of (E) $\prt_t
u-\xD u+u^q=0$ in $\mathbb{R}^N\times(0,\infty)$ admits an initial trace which
is a nonnegative Borel measure, outer regular with respect to the fine topology
associated to the Bessel capacity $C_{\frac{2}{q},q'}$ in $\BBR^N$
($q'=q/q-1)$) and absolutely continuous with respect to this capacity. If $\nu$
is a nonnegative Borel measure in $\BBR^N$ with the above properties we
construct a positive solution $u$ of (E) with initial trace $\gn$ and we prove
that this solution is the unique $\gs$-moderate solution of (E) with such an
initial trace. Finally we prove that every positive solution of (E) is
$\gs$-moderate.


title: Nonlinear Model Reduction via an Adaptive Weighting of Snapshots

abstract:
  In this paper, we propose a new approach to model reduction of parameterized
partial differential equations (PDEs) based on the concept of adaptive reduced
bases. The presented approach is particularly suited for large-scale nonlinear
systems characterized by parameter variations. Instead of using a global basis
to construct a global reduced model, the proposed method approximates the
original system by multiple lower-dimensional subspaces. Each localized reduced
basis is generated by the SVD of a weighted snapshot ensemble; here, each
weighting coefficient is a function of the input parameter. Compared with a
global model reduction method, such as the classical POD, the adaptive model
reduction method could yield a more accurate solution with a fixed subspace
dimension. Moreover, we combine the adaptive reduced model with the chord
iteration to solve elliptic PDEs in a computationally efficient fashion. The
potential of the method for achieving large speedups, while maintaining good
accuracy, is demonstrated for both elliptic and parabolic PDEs in a few
numerical examples.


title: $\phi$-meson photoproduction on Hydrogen in the neutral decay mode

abstract:
  We report the first measurement of the photoproduction cross section of the
$\phi$ meson in its neutral decay mode in the reaction $\gamma p \to
p\phi(K_SK_L)$. The experiment was performed with a tagged photon beam of
energy $1.6 \le E_\gamma \le 3.6$ GeV incident on a liquid hydrogen target of
the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility.
The $p \phi$ final state is identified via reconstruction of $K_S$ in the
invariant mass of two oppositely charged pions and by requiring the missing
particle in the reaction $\gamma p \to p K_S X$ to be $K_L$. The presented
results significantly enlarge the existing data on $\phi$-photoproduction.
These data, combined with the data from the charged decay mode, will help to
constrain different mechanisms of $\phi$ photoproduction.


title:
Search for excited electrons and muons in sqrt(s)=8 TeV proton-proton
  collisions with the ATLAS detector

abstract:
  The ATLAS detector at the LHC is used to search for excited electrons and
excited muons in the channel pp -> ll* -> llgamma, assuming that excited
leptons are produced via contact interactions. The analysis is based on 13 fb-1
of pp collisions at a centre-of-mass energy of 8 TeV. No evidence for excited
leptons is found, and a limit is set at the 95% credibility level on the cross
section times branching ratio as a function of the excited-lepton mass m_l*.
For m_l* > 0.8 TeV, the respective upper limits on sigma*B(l* -> lgamma) are
0.75 fb and 0.90 fb for the e* and mu* searches. Limits on sigma*B are
converted into lower bounds on the compositeness scale Lambda. In the special
case where Lambda = m_l*, excited-electron and excited-muon masses below 2.2
TeV are excluded.


title: Mathematical model of concentrating solar cooker

abstract:
  The main purpose of this work is to obtain a mathematical model consistent
with the thermal behavior of concentrating solar cookers, such as
Jorhejpataranskua. We also want to simulate different conditions respect to the
parameters involved of several materials for its construction and efficiency.
The model is expressed in terms of a coupled nonlinear system of differential
equations which are solved using Mathematica 8. The results obtained by our
model are compared with measurements of solar cooker in field testing
operation. We obtained good results in agreement with experimental data.
Moreover, the simulation results are used by calculating cooking power and
standardized cooking power of solar cooker for different parameters.


title: Gauge-flation confronted with Planck

abstract:
  Gauge-flation is a recently proposed model in which inflation is driven
solely by a non-Abelian gauge field thanks to a specific higher order
derivative operator. The nature of the operator is such that it does not
introduce ghosts. We compute the cosmological scalar and tensor perturbations
for this model, improving over an existing computation. We then confront these
results with the Planck data. The model is characterized by the quantity \gamma
= (g^2 Q^2)/H^2 (where g is the gauge coupling constant, Q the vector vev, and
H the Hubble rate). For \gamma < 2, the scalar perturbations show a strong
tachyonic instability. In the stable region, the scalar power spectrum n_s is
too low at small \gamma, while the tensor-to-scalar ratio r is too high at
large \gamma. No value of \gamma leads to acceptable values for n_s and r, and
so the model is ruled out by the CMB data. The same behavior with \gamma was
obtained in Chromo-natural inflation, a model in which inflation is driven by a
pseudo-scalar coupled to a non-Abelian gauge field. When the pseudo-scalar can
be integrated out, one recovers the model of Gauge-flation plus corrections. It
was shown that this identification is very accurate at the background level,
but differences emerged in the literature concerning the perturbations of the
two models. On the contrary, our results show that the analogy between the two
models continues to be accurate also at the perturbative level.


title:
An operator van der Corput estimate arising from oscillatory
  Riemann-Hilbert problems

abstract:
  We study an operator analogue of the classical problem of finding the rate of
decay of an oscillatory integral on the real line. This particular problem
arose in the analysis of oscillatory Riemann-Hilbert problems associated with
partial differential equations in the Ablowitz-Kaup-Newell-Segur hierarchy, but
is interesting in its own right as a question in harmonic analysis and
oscillatory integrals. As was the case in earlier work of the first author, the
approach is general and purely real-variable. The resulting estimates we
achieve are strongly uniform as a function of the phase and can simultaneously
accommodate phases with low regularity (as low as $C^{1,\alpha}$), local
singularities, and essentially arbitrary sets of stationary points that
degenerate to finite or infinite order.


title: Dual models of the neutrino mass spectrum

abstract:
  We show that any model with a homogeneous relationship among elements of the
neutrino mass matrix with one mass hierarchy yields predictions for the
oscillation parameters and Majorana phases similar to those given by a model
with the same homogeneous relationship among cofactors of the neutrino mass
matrix with the opposite mass hierarchy, except when the lightest mass is of
order 20 meV or less.


title:
Irreducible Representations Of Oscillatory And Swirling Flows In Active
  Soft Matter

abstract:
  Recent experiments imaging fluid flow around swimming microorganisms have
revealed complex time-dependent velocity fields that differ qualitatively from
the stresslet flow commonly employed in theoretical descriptions of active
matter. Here we obtain the most general flow around a finite sized active
particle by expanding the surface stress in irreducible Cartesian tensors. This
expansion, whose first term is the stresslet, must include, respectively,
third-rank polar and axial tensors to minimally capture crucial features of the
active oscillatory flow around translating Chlamydomonas and the active
swirling flow around rotating Volvox. The representation provides explicit
expressions for the irreducible symmetric, antisymmetric and isotropic parts of
the continuum active stress. Antisymmetric active stresses do not conserve
orbital angular momentum and our work thus shows that spin angular momentum is
necessary to restore angular momentum conservation in continuum hydrodynamic
descriptions of active soft matter.

categories: cond-mat.soft physics.bio-ph physics.flu-dyn q-bio.CB


title: Scattering in AdS(2)/CFT(1) and the BES Phase

abstract:
  We study worldsheet scattering for the type IIA superstring in AdS(2) x S(2)
x T(6). Using the Green--Schwarz action to quartic order in fermions we take
the near-BMN limit, where as in the AdS(3)/CFT(2) case there are both massive
and massless excitations. For the massive excitations we compute all possible
tree-level processes, and show that these agree with a truncated version of the
exact AdS(5) x S(5) S-matrix. We also compute several S-matrix elements
involving massless excitations. At one loop we find that the dressing phase is
the same Hernandes-Lopez phase appearing in AdS(5)/CFT(4). We see the same
phase when calculating this by semiclassical means using the PSU(1,1|2)/U(1)^2
coset sigma model, for which we can also study the scattering of fermions. This
supports the conjecture that the all-loop dressing phase is again the BES
phase, rather than a new phase like that seen in AdS(3)/CFT(2).


title:
Organometallic Hexahapto Functionalization of Single Layer Graphene as a
  Route to High Mobility Graphene Devices

abstract:
  Organometallic hexahapto chromium metal complexation of single layer
graphene, which involves constructive rehybridization of the graphene pi-system
with the vacant chromium d orbital, leads to field effect devices which retain
a high degree of the mobility with enhanced on-off ratio. This hexahapto mode
of bonding between metal and graphene is quite distinct from the modification
in electronic structure induced by conventional covalent sigma-bond formation
with creation of sp3 carbon centers in graphene lattice and this chemistry is
reversible.


title: CP violation in charm decays

abstract:
  Results on CP violation searches in charm decays performed by the LHCb
experiment are reviewed. These include an update of the measurement of the
difference in time-integrated {\em CP} asymmetry between $D^0\to K^-K^+$ and
$D^0\to \pi^-\pi^+$ using $D^0$ from prompt $D^{*+}, a measurement of the same
observable using an independent sample of $D^0$ from semileptonic B decays, and
CP violation searches performed on charged $D$ mesons. All results have been
released since FPCP 2012.


title: Photometric Survey to Search for Field sdO Pulsators

abstract:
  We present the results of a campaign to search for subdwarf O (sdO) star
pulsators among bright field stars. The motivation for this project is the
recent discovery by Randall et al. (2011), of four rapidly pulsating sdO stars
in the globular cluster Omega Cen, with Teff near 50,000 K, 5.4 < log g < 6.0,
and hydrogen-rich atmospheres. The only previously known sdO pulsator is
significantly hotter at 68,500 K and log g = 6.1. All of the sdO pulsators
identified so far are fainter than 17.4 in the V band and, thus, are poor
candidates for an in-depth follow-up with asteroseismology. We therefore
obtained high S/N light curves and spectroscopy for a number of field sdO stars
to attempt to discover bright counterparts to these stars, particularly the
Omega Cen pulsators. Our primary sample consisted of 19 sdO stars with
hydrogen-rich atmospheres, log N(He)/N(H) < -1.0, effective temperatures in the
range 40,000 K < Teff < 67,000 K, and surface gravities 5.3 < log g < 6.1. We
also observed 17 additional helium-rich sdO stars with log N(He)/N(H) > -0.1
and similar temperatures and gravities. To date, we have found no detectable
pulsations at amplitudes above 0.08% (4 times the mean noise level) in any of
the 36 field sdO stars that we observed. The presence of pulsations in Omega
Cen sdO stars and their apparent absence in seemingly comparable field sdO
stars is perplexing. While very suggestive, the significance of this result is
difficult to assess more completely right now due to remaining uncertainties
about the temperature width and purity of the Omega Cen instability strip and
the existence of any sdO pulsators with weaker amplitudes than the current
detection limit in globular clusters.


title: Bayesian ensemble learning for image denoising

abstract:
  Natural images are often affected by random noise and image denoising has
long been a central topic in Computer Vision. Many algorithms have been
introduced to remove the noise from the natural images, such as Gaussian,
Wiener filtering and wavelet thresholding. However, many of these algorithms
remove the fine edges and make them blur. Recently, many promising denoising
algorithms have been introduced such as Non-local Means, Fields of Experts, and
BM3D. In this paper, we explore Bayesian method of ensemble learning for image
denoising. Ensemble methods seek to combine multiple different algorithms to
retain the strengths of all methods and the weaknesses of none. Bayesian
ensemble models are Non-local Means and Fields of Experts, the very successful
recent algorithms. The Non-local Means presumes that the image contains an
extensive amount of self-similarity. The approach of the Fields of Experts
model extends traditional Markov Random Field model by learning potential
functions over extended pixel neighborhoods. The two models are implemented and
image denoising is performed on natural images. The experimental results
obtained are used to compare with the single algorithm and discuss the ensemble
learning and their approaches. Comparing to the results of Non-local Means and
Fields of Experts, Ensemble learning showed improvement nearly 1dB.


title: PAHs as tracers of local AGN-Starburst connection

abstract:
  The main purpose of this research was to investigate how energetic processes
associated with Active Galactic Nuclei are related to those due to nuclear or
circumnuclear star formation activity. Photometric and spectroscopic data were
used to discriminate these processes in a sample of starburst, infrared
galaxies and AGNs. Herein, we propose new diagnostic diagrams based on the 7.7
{\mu}m polycyclic aromatic hydrocarbon emission band, the L(MIR, FIR) infrared
ratio and the q parameter. The diagnostic diagrams allow us to discriminate the
behavior of quasars and Seyfert 1-Seyfert 2 galaxies from starburst and
LIRGs-ULIRGs objects.


title:
Design and characterization of a lumped element single-ended
  superconducting microwave parametric amplifier with on-chip flux bias line

abstract:
  We demonstrate a lumped-element Josephson parametric amplifier, using a
single-ended design that includes an on-chip, high-bandwidth flux bias line.
The amplifier can be pumped into its region of parametric gain through either
the input port or through the flux bias line. Broadband amplification is
achieved at a tunable frequency $\omega/2 \pi$ between 5 to 7 GHz with
quantum-limited noise performance, a gain-bandwidth product greater than 500
MHz, and an input saturation power in excess of -120 dBm. The bias line allows
fast frequency tuning of the amplifier, with variations of hundreds of MHz over
time scales shorter than 10 ns.


title: First results from p-Pb collisions at the LHC

abstract: The first results from p-Pb collisions at sqrt(sNN) = 5.02 TeV are discussed.


title: Programmable discrimination with an error margin

abstract:
  The problem of optimally discriminating between two completely unknown qubit
states is generalized by allowing an error margin. It is visualized as a
device---the programmable discriminator---with one data and two program ports,
each fed with a number of identically prepared qubits---the data and the
programs. The device aims at correctly identifying the data state with one of
the two program states. This scheme has the unambiguous and the minimum-error
schemes as extremal cases, when the error margin is set to zero or it is
sufficiently large, respectively. Analytical results are given in the two
situations where the margin is imposed on the average error probability---weak
condition---or it is imposed separately on the two probabilities of assigning
the state of the data to the wrong program---strong condition. It is a general
feature of our scheme that the success probability rises sharply as soon as a
small error margin is allowed, thus providing a significant gain over the
unambiguous scheme while still having high confidence results.


title: A Survey for Very Short-Period Planets in the Kepler Data

abstract:
  We conducted a search for very short-period transiting objects in the
publicly available Kepler dataset. Our preliminary survey has revealed four
planetary candidates, all with orbital periods less than twelve hours. We have
analyzed the data for these candidates using photometric models that include
transit light curves, ellipsoidal variations, and secondary eclipses to
constrain the candidates' radii, masses, and effective temperatures. Even with
masses of only a few Earth masses, the candidates' short periods mean they may
induce stellar radial velocity signals (a few m/s) detectable by currently
operating facilities. The origins of such short-period planets are unclear, but
we discuss the possibility that they may be the remnants of disrupted hot
Jupiters. Whatever their origins, if confirmed as planets, these candidates
would be among the shortest-period planets ever discovered. Such planets would
be particularly amenable to discovery by the planned TESS mission.


title: Spectral Synthesis of Star-forming Galaxies in the Near-Infrared

abstract:
  The near-infrared spectral region is becoming a very useful wavelength range
to detect and quantify the stellar population of galaxies. Models are
developing to predict the contribution of TP-AGB stars, that should dominate
the NIR spectra of populations 0.3 to 2 Gyr old. When present in a given
stellar population, these stars leave unique signatures that can be used to
detect them unambiguously. However, these models have to be tested in a
homogeneous database of star-forming galaxies, to check if the results are
consistent with what is found from different wavelength ranges. In this work we
performed stellar population synthesis on the nuclear and extended regions of
23 star-forming galaxies to understand how the star-formation tracers in the
near-infrared can be used in practice. The stellar population synthesis shows
that for the galaxies with strong emission in the NIR, there is an important
fraction of young/intermediate population contributing to the spectra, which is
probably the ionisation source in these galaxies. Galaxies that had no emission
lines measured in the NIR were found to have older average ages and less
contribution of young populations. Although the stellar population synthesis
method proved to be very effective to find the young ionising population in
these galaxies, no clear correlation between these results and the NIR spectral
indexes were found. Thus, we believe that, in practice, the use of these
indexes is still very limited due to observational limitations.


title: Scattering of scalar waves on a single crystalline plane

abstract:
  Scattering of a scalar particle on a crystalline plane with quadratic cell
and identical fixed scatterers is solved precisely. Contradiction of the
standard scattering theory is pointed out.