title:
Perturbative Analysis of the Electron EDM and CP Violation in Two Higgs
  Doublet Models

abstract:
  I consider a general two Higgs doublet model with CP violation. I give a
perturbative expansion for the mass eigenstates in terms of the small CP
violating phase. I use these analytical expressions to show that
$\mathcal{O}(10^{-2})$ CP violation is allowed by the experimental bounds on
the electron electric dipole momnent in some regions of the parameter space.
These regions also include parameters that are expected to give a strongly
first order electroweak phase transition required for electroweak baryogenesis.
I also comment on how to incorporate the CP violation into the searches for a
strongly first order electroweak phase transition which could explain the
matter/anti-matter asymmetry in the universe.


title: Mode coupling in spin torque oscillators

abstract:
  A number of recent experimental works have shown that the dynamics of a
single spin torque oscillator can exhibit complex behavior that stems from
interactions between two or more modes of the oscillator. Examples are observed
mode-hopping or mode coexistence. There has been some intial work indicating
how the theory for a single-mode (macro-spin) spin torque oscillator should be
generalized to include several modes and the interactions between them. In the
present work, we derive such a theory starting with the Landau-Lifshitz-Gilbert
equation for magnetization dynamics. We compare our results with the
single-mode theory, and show how it is a natural extension of that theory to
include mode interactions.


title: Low-energy theory of a two-dimensional itinerant chiral magnet

abstract:
  Effective actions, such as nonlinear sigma models, are important tools in
studying low-energy fluctuations of magnetically ordered states. Here we derive
an effective action for the smooth order-parameter distortions of noncoplanar
magnetic textures [with an SO(3) order parameter, as opposed to the
SO(3)/SO(2)=S^2 of collinear magnets] coupled to itinerant electrons.
Noncoplanar magnetic textures commonly arise in the presence of
electron-mediated long-range spin exchange interactions, giving rise to the
emergence of rich electronic phenomena such as anomalous quantum Hall effect.
We parameterize the smooth order-parameter distortions of such a magnetic
texture by certain non-Abelian fields, and derive the action in terms of these
fields by integrating out the itinerant electrons. As a concrete example, we
perform explicit calculations for a triangular-lattice model with tetrahedral
magnetic ordering. The action encodes the charge and spin quantum-Hall
responses as well as the energetics of twisting the magnetic texture.


title: Quantum pumping in helimagnet heterostructures

abstract:
  Spin-dependent diffraction occurs in helimagnet-related transport processes.
In this work, we investigated quantum pumping properties in the
normal-metal/helimagnet/normal-metal heterostructure driven by two out of phase
time-dependent gate potentials. At the condition when one of the diffracted
beams goes out of the horizon the pumped charge and spin currents demonstrate
sharp dips and rises as a function of the helimagnet spiral wavevector $q$. At
small and large $q$'s, the transmission and pumping properties approach the
behaviors of a ferromagnet and an insulating barrier, respectively. For
different helimagnet spiral periods, the diffracted angles are different. As a
result, the pumped charge and spin currents demonstrate multiple maximal and
minimal peaks as a function of $q$, hence, sensitively depend on the helimagnet
spin configuration. All the pumping properties can be interpreted by the
quantum gate-switching mechanisms.


title:
Effect of resonance on the existence of periodic solutions for strongly
  damped wave equation

abstract:
  We are interested in the differential equation $\ddot u(t) = -A u(t) - c A
\dot u(t) + \lambda u(t) + F(t,u(t))$, where $c > 0$ is a damping factor, $A$
is a sectorial operator and $F$ is a continuous map. We consider the situation
where the equation is at resonance at infinity, which means that $\lambda$ is
an eigenvalue of $A$ and $F$ is a bounded map. We introduce new geometrical
conditions for the nonlinearity $F$ and use topological degree methods to find
$T$-periodic solutions for this equation as fixed points of Poincar\'e
operator.


title:
Downlink Multi-Antenna Heterogeneous Cellular Network with Load
  Balancing

abstract:
  We model and analyze heterogeneous cellular networks with multiple antenna
BSs (multi-antenna HetNets) with K classes or tiers of base stations (BSs),
which may differ in terms of transmit power, deployment density, number of
transmit antennas, number of users served, transmission scheme, and path loss
exponent. We show that the cell selection rules in multi-antenna HetNets may
differ significantly from the single-antenna HetNets due to the possible
differences in multi-antenna transmission schemes across tiers. While it is
challenging to derive exact cell selection rules even for maximizing
signal-to-interferenceplus-noise-ratio (SINR) at the receiver, we show that
adding an appropriately chosen tier-dependent cell selection bias in the
received power yields a close approximation. Assuming arbitrary selection bias
for each tier, simple expressions for downlink coverage and rate are derived.
For coverage maximization, the required selection bias for each tier is given
in closed form. Due to this connection with biasing, multi-antenna HetNets may
balance load more naturally across tiers in certain regimes compared to
single-antenna HetNets, where a large cell selection bias is often needed to
offload traffic to small cells.


title:
Experimental Verification of Quantum Discord in Continuous-Variable
  States

abstract:
  We introduce a simple and efficient technique to verify quantum discord in
unknown Gaussian states and a certain class of non-Gaussian states. We show
that any separation in the peaks of the marginal distributions of one subsystem
conditioned on two different outcomes of homodyne measurements performed on the
other subsystem indicates correlation between the corresponding quadratures,
and hence nonzero discord. We also apply this method to non-Gaussian states
that are prepared by overlapping a statistical mixture of coherent and vacuum
states on a beam splitter. We experimentally demonstrate this technique by
verifying nonzero quantum discord in a bipartite Gaussian and certain class of
non-Gaussian states.


title: Focal Conic Flower Textures at Curved Interfaces

abstract:
  Focal conic domains (FCDs) in smectic-A liquid crystals have drawn much
attention both for their exquisitely structured internal form and for their
ability to direct the assembly of micro- and nanomaterials in a variety of
patterns. A key to directing FCD assembly is control over the eccentricity of
the domain. Here, we demonstrate a new paradigm for creating spatially varying
FCD eccentricity by confining a hybrid-aligned smectic with curved interfaces.
In particular, we manipulate interface behavior with colloidal particles in
order to experimentally produce two examples of what has recently been dubbed
the flower texture, where the focal hyperbolae diverge radially outward from
the center of the texture, rather than inward as in the canonical eventail or
fan texture. We explain how this unconventional assembly can arise from
appropriately curved interfaces. Finally, we present a model for this system
that applies the law of corresponding cones, showing how FCDs may be embedded
smoothly within a "background texture" of large FCDs and concentric spherical
layers, in a manner consistent with the qualitative features of the smectic
flower. Such understanding could potentially lead to disruptive liquid crystal
technologies beyond displays, including patterning, smart surfaces, microlens
arrays, sensors and nanomanufacturing.


title:
A microscopic model for detecting the surface states photoelectrons in
  Topological Insulators

abstract:
  We present a model for the photoelectrons emitted from the surface of a
Topological insulator induced by a polarized laser source. The model is based
on the tunneling of the surface electrons into the vacuum in the presence of a
photon field. Using the Hamiltonian which describes the coupling of the photons
to the surface electrons we compute the intensity and polarization of the
photoelectrons.


title:
Disappearance of a narrow Mg II absorption system with a measured
  velocity up to $\rm 166,000 km s^{-1}$

abstract:
  Quasar J152645.61+193006.7 ($z_{\rm e}=2.5771$) was observed by the Sloan
Digital Sky Survey (SDSS) on 2006 May 31, and again on 2011 April 9. The time
interval of the SDSS two observations is 497.4 days at the quasar rest frame.
From the spectra of this quasar, we detect a phenomenon of disappearance of a
narrow $\rm Mg II \lambda\lambda2796,2803$ absorption system with a velocity up
to $\rm 166,129 km s^{-1}$ with respect to the quasar. This disappearance event
can be caused by changes in the ionization state of absorbing gas or by the
bulk motion of the absorbing gas across the quasar sightline. The coverage
fraction analysis shows that this absorber partially covers the background
emission sources with an effective coverage fraction of $C_{\rm
f}=0.40\pm0.06$. The time variation analysis and the coverage fraction analysis
imply that this absorber might be intrinsic to the quasar. However, the
scenario of a cosmologically separated foreground object located at $z=0.9170$
accounting for the phenomenon cannot be ruled out according to current
available data.


title: Light bending in radiation background

abstract:
  We consider the velocity shift of light in presence of radiation emitted by a
black body. Within geometric optics formalism we calculate the bending angle of
a light ray when there is a gradient in the energy density. We model the
bending for two simplified cases. The bending angle is proportional to the
inverse square power of the impact parameter ($\propto 1/b^2$) when the
dilution of energy density is spherically symmetric. The bending angle is
inversely proportional to the impact parameter ($\propto 1/b$) when the energy
density dilutes cylindrically. Assuming that a neutron star is an isothermal
black body, we estimate the order of magnitude for such bending angle and
compare it with the bending angle by magnetic field.


title: Reconciliation of MOND and Dark Matter theory

abstract:
  I show that Modified Newtonian Dynamics (MOND) is equivalent to assuming an
isothermal dark matter density profile, with its density related to the
enclosed total baryonic mass. This density profile can be deduced by physical
laws if a dark matter core exists and if the baryonic component is
spherically-symmetric, isotropic and isothermal. All the usual predictions of
MOND, as well as the universal constant $a_0$, can be derived in this model.
Since the effects of baryonic matter are larger in galaxies than in galaxy
clusters, this result may explain why MOND appears to work well for galaxies
but poorly for clusters. As a consequence of the results presented here, MOND
can be regarded as a misinterpretation of a particular dark matter density
profile.


title: Nova Aquilae 1918 (V603 Aql) Faded by 0.44 mag/century from 1938-2013

abstract:
  We present the light curve of the old nova V603 Aql (Nova Aql 1918) from
1898-1918 and 1934-2013 using 22,721 archival magnitudes. All of our magnitudes
are either in, or accurately transformed into, the Johnson $B$ and $V$
magnitude systems. This is vital because offsets in old sequences and the
visual-to-$V$ transformation make for errors from 0.1-1.0 magnitude if not
corrected. Our V603 Aql light curve is the first time that this has been done
for any nova. Our goal was to see the evolution of the mass accretion rate on
the century time scale, and to test the long-standing prediction of the
Hibernation model that old novae should be fading significantly in the century
after their eruption is long over. The 1918 nova eruption was completely
finished by 1938 when the nova decline stopped, and when the star had faded to
fainter than its pre-nova brightness of $B=11.43 \pm 0.03$ mag. We find that
the nova light from 1938-2013 was significantly fading, with this being seen
consistently in three independent data sets (the Sonneberg plates in $B$, the
AAVSO $V$ light curve, and the non-AAVSO $V$ light curve). We find that V603
Aql is declining in brightness at an average rate of $0.44 \pm 0.04$ mag per
century since 1938. This work provides remarkable confirmation of an important
prediction of the Hibernation model.


title:
Searching for low-lying multi-particle thresholds in lattice
  spectroscopy

abstract:
  We explore the Euclidean-time tails of odd-parity nucleon correlation
functions in a search for the S-wave pion-nucleon scattering-state threshold
contribution. The analysis is performed using 2+1 flavor 32^3 x 64 PACS-CS
gauge configurations available via the ILDG. Correlation matrices composed with
various levels of fermion source/sink smearing are used to project low-lying
states. The consideration of 25,600 fermion propagators reveals the presence of
more than one state in what would normally be regarded as an
eigenstate-projected correlation function. This observation is in accord with
the scenario where the eigenstates contain a strong mixing of single and
multi-particle states but only the single particle component has a strong
coupling to the interpolating field. Employing a two-exponential fit to the
eigenvector-projected correlation function, we are able to confirm the presence
of two eigenstates. The lower-lying eigenstate is consistent with a N-pi
scattering threshold and has a relatively small coupling to the three-quark
interpolating field. We discuss the impact of this small scattering-state
contamination in the eigenvector projected correlation function on previous
results presented in the literature.


title: Relations among characteristic classes of manifold bundles

abstract:
  We study relations among characteristic classes of smooth manifold bundles
with highly-connected fibers. For bundles with fiber the connected sum of $g$
copies of a product of spheres $S^d \times S^d$ and an odd $d$, we find
numerous algebraic relations among the so-called "generalized
Miller-Morita-Mumford classes". For all $g > 1$, we show that these infinitely
many classes are algebraically generated by a finite subset.
  Our results contrast with the fact that there are no algebraic relations
among these classes in a range of cohomological degrees that grows linearly
with $g$, according to recent homological stability results. In the case of
surface bundles ($d=1$), our approach recovers some previously known results
about the structure of the classical "tautological ring", as introduced by
Mumford, using only the tools of algebraic topology.


title: $B \to K \etap$ decays in the SM with fourth generation fermions

abstract:
  By employing the perturbative QCD (pQCD) factorization approach, we calculate
the new physics contributions to the four $B \to K \etap$ decays in the
Standard Model (SM) with a fourth generation of fermions (SM4), induced by the
loop diagrams involving $\tp$ quark. Within the considered parameter space of
the SM4 we find that (a) the next-to-leading order (NLO) pQCD predictions for
the branching ratios and CP-violating asymmetries in both the SM and SM4
generally agree with the data within one standard deviation; (b) for $Br(B \to
K \eta)$, the inclusion of the fourth generation contributions can improve the
agreement between the theoretical predictions and the data effectively; (c) for
$Br(B \to K \etar)$, however, the decrease due to $\tp$ loops is disfavored by
the data; and (d) the new physics corrections to the CP-violating asymmetries
of the considered decays are about 10% only.


title: Coupled Cluster Channels in the Homogeneous Electron Gas

abstract:
  We discuss diagrammatic modifications to the coupled cluster doubles (CCD)
equations, wherein different groups of terms out of rings, ladders,
crossed-rings and mosaics can be removed to form approximations to the coupled
cluster method, of interest due to their similarity with various types of
random phase approximations. The finite uniform electron gas is benchmarked for
14- and 54-electron systems at the complete basis set limit over a wide density
range and performance of different flavours of CCD are determined. These
results confirm that rings generally overcorrelate and ladders generally
undercorrelate; mosaics-only CCD yields a result surprisingly close to CCD. We
use a recently developed numerical analysis [J. J. Shepherd and A. Gr\"uneis,
Phys. Rev. Lett. 110, 226401 (2013)] to study the behaviours of these methods
in the thermodynamic limit. We determine that the mosaics, on forming the
Brueckner Hamltonian, open a gap in the effective one-particle eigenvalues at
the Fermi energy. Numerical evidence is presented which shows that methods
based on this renormalisation have convergent energies in the thermodynamic
limit including mosaic-only CCD, which is just a renormalised MP2. All other
methods including only a single channel, namely ladder-only CCD, ring-only CCD
and crossed-ring-only CCD, appear to yield divergent energies; incorporation of
mosaic terms prevents this from happening.

categories: physics.chem-ph cond-mat.mtrl-sci cond-mat.other cond-mat.quant-gas


title: FM 047-02: a collisional pair of galaxies with a ring

abstract:
  Aims. We investigate the nature of the galaxy pair FM 047-02, which has been
proposed as an archetype of the Solitaire types of peculiar (collisional) ring
galaxies. Methods. The study is based on long-slit spectrophotometric data in
the range of 3500-9500 angstrons obtained with the Gemini Multi-Object


title: Gender Classification Using Gradient Direction Pattern

abstract:
  A novel methodology for gender classification is presented in this paper. It
extracts feature from local region of a face using gray color intensity
difference. The facial area is divided into sub-regions and GDP histogram
extracted from those regions are concatenated into a single vector to represent
the face. The classification accuracy obtained by using support vector machine
has outperformed all traditional feature descriptors for gender classification.
It is evaluated on the images collected from FERET database and obtained very
high accuracy.


title: Radio-continuum Observations of a Giant Radio Source QSO J0443.8-6141

abstract:
  We report the discovery of a giant double-lobed (lobe-core-lobe)
radio-continuum structure associated with QSO J0443.8-6141 at z=0.72. This QSO
was originally identified during the follow-up of a sample of ROSAT All Sky
Survey sources at radio and optical frequencies. With a linear size of ~0.77
Mpc, QSO J0443.8-6141 is classified as a giant radio source (GRS); based on its
physical properties, we classify QSO J0443.8-6141 as a FR II radio galaxy.
High-resolution observations are required to reliably identify GRSs; the next
generation of southern-sky radio and optical surveys will be crucial to
increasing our sample of these objects.


title:
Using the topology of large-scale structure in the WiggleZ Dark Energy
  Survey as a cosmological standard ruler

abstract:
  We present new and accurate measurements of the cosmic distance-redshift
relation, spanning 0.2 < z < 1, using the topology of large-scale structure as
a cosmological standard ruler. Our results derive from an analysis of the
Minkowski functionals of the density field traced by the WiggleZ Dark Energy
Survey. The Minkowski functionals are a set of statistics which completely
describe the topological nature of each isodensity surface within the field, as
a function of the density value. Given the shape of the underlying matter power
spectrum, measured by fluctuations in the Cosmic Microwave Background
radiation, the expected amplitudes of the Minkowski functionals are specified
as an excursion set of a Gaussian random field, with minimal non-Gaussian
corrections for the smoothing scales > 10 Mpc/h considered in this analysis.
The measured amplitudes then determine the cosmic distance D_V(z), which we
obtain with 3-7% accuracies in six independent redshift slices, with the
standard ruler originating in the known curvature of the model power spectrum
at the smoothing scale. We introduce a new method for correcting the
topological statistics for the sparse-sampling of the density field by the
galaxy tracers, and validate our overall methodology using mock catalogues from
N-body simulations. Our distance measurements are consistent with standard
models which describe the cosmic expansion history, and with previous analyses
of baryon acoustic oscillations (BAOs) detected by the WiggleZ Survey, with the
topological results yielding a higher distance precision by a factor of 2.
However, the full redshift-space power-spectrum shape is required to recover
the topological distances, in contrast to the preferred length scale imprinted
by BAOs, which is determined by simpler physics.


title:
The "universal property" of Horizon Entropy Sum of Black Holes in Four
  Dimensional Asymptotical (anti-)de-Sitter Spacetime Background

abstract:
  We present a new ``universal property'' of entropy, that is the ``entropy
sum'' relation of black holes in four dimensional (anti-)de-Sitter asymptotical
background. They depend only on the cosmological constant with the necessary
effect of the un-physical ``virtual'' horizon included in the spacetime where
only the cosmological constant, mass of black hole, rotation parameter and
Maxwell field exist. When there is more extra matter field in the spacetime,
one will find the ``entropy sum'' is also dependent of the strength of these
extra matter field. For both cases, we conclude that the ``entropy sum'' does
not depend on the conserved charges $M$, $Q$ and $J$, while it does depend on
the property of background spacetime. We will mainly test the ``entropy sum''
relation in static, stationary black hole and some black hole with extra matter
source (scalar hair and higher curvature) in the asymptotical (anti-)de-sitter
spacetime background. Besides, we point out a newly found counter example of
the mass independence of the ''entropy product'' relation in the spacetime with
extra scalar hair case, while the ``entropy sum'' relation still holds. These
result are indeed suggestive to some underlying microscopic mechanism.
Moreover, the cosmological constant and extra matter field dependence of the
``entropy sum'' of all horizon seems to reveal that ``entropy sum'' is more
general as it is only related to the background field. For the case of
asymptotical flat spacetime without any matter source, we give a note for the
Kerr black hole case in appendix. One will find only mass dependence of
``entropy sum'' appears. It makes us believe that, considering the dependence
of ``entropy sum'', the mass background field may be regarded as the next order
of cosmological constant background field and extra matter field.


title: Future Neutrino Oscillation Sensitivities for LBNE

abstract:
  The primary goal of the Long-Baseline Neutrino Experiment (LBNE) is to
measure the neutrino mixing matrix parameters. The design, optimized to search
for CP violation and to determine the neutrino mass hierarchy, includes a large
$\mathcal{O}(10$ kt) Liquid Argon Time Projection Chamber (LAr TPC) at 1300 km
downstream of a wide-band neutrino beam. A brief introduction to the neutrino
mixing parameters will be followed by a discussion of sensitivity study
analysis methods and a summary of the results for LBNE. The studies include
comparisons with the Tokai-to-Kamioka (T2K) and NuMI Off-axis electron-neutrino
Appearance (NO$\nu$A) experiments as well as combined sensitivities. Finally,
the impact of including a realistic set of systematic uncertainties will be
presented.


title: Generators and relations for n-qubit Clifford operators

abstract:
  We define a normal form for Clifford circuits, and we prove that every
Clifford operator has a unique normal form. Moreover, we present a rewrite
system by which any Clifford circuit can be reduced to normal form. This yields
a presentation of Clifford operators in terms of generators and relations.


title:
Strain-rate and temperature-driven transition in the shear
  transformation zone for two-dimensional amorphous solids

abstract:
  We couple the recently developed self-learning metabasin escape algorithm,
which enables efficient exploration of the potential energy surface (PES), with
shear deformation to elucidate strain-rate and temperature effects on the shear
transformation zone (STZ) characteristics in two-dimensional amorphous solids.
In doing so, we report a transition in the STZ characteristics that can be
obtained through either increasing the temperature or decreasing the strain
rate. The transition separates regions having two distinct STZ characteristics.
Specifically, at high temperatures and high strain rates, we show that the STZs
have characteristics identical to those that emerge from purely strain-driven,
athermal quasistatic atomistic calculations. At lower temperatures and
experimentally relevant strain rates, we use the newly coupled PES + shear
deformation method to show that the STZs have characteristics identical to
those that emerge from a purely thermally activated state. The specific changes
in STZ characteristics that occur in moving from the strain-driven to thermally
activated STZ regime include a 33% increase in STZ size, faster spatial decay
of the displacement field, a change in the deformation mechanism inside the STZ
from shear to tension, a reduction in the stress needed to nucleate the first
STZ, and finally a notable loss in characteristic quadrupolar symmetry of the
surrounding elastic matrix that has previously been seen in athermal,
quasistatic shear studies of STZs.


title: Globalization with probabilistic convexity

abstract:
  We introduce a notion of probabilistic convexity and generalize some
classical globalization theorems in Alexandrov geometry. A weighted
Alexandrov's lemma is developed as a basic tool.


title:
On the energy-critical fractional Sch\"odinger equation in the radial
  case

abstract:
  We consider the Cauchy problem for the energy-critical nonlinear
Schr\"odinger equation with fractional Laplacian (fNLS) in the radial case. We
obtain global well-posedness and scattering in the energy space in the
defocusing case, and in the focusing case with energy below the ground state.


title: Systematic Error-Correcting Codes for Rank Modulation

abstract:
  The rank-modulation scheme has been recently proposed for efficiently storing
data in nonvolatile memories. Error-correcting codes are essential for rank
modulation, however, existing results have been limited. In this work we
explore a new approach, \emph{systematic error-correcting codes for rank
modulation}. Systematic codes have the benefits of enabling efficient
information retrieval and potentially supporting more efficient encoding and
decoding procedures. We study systematic codes for rank modulation under
Kendall's $\tau$-metric as well as under the $\ell_\infty$-metric.
  In Kendall's $\tau$-metric we present $[k+2,k,3]$-systematic codes for
correcting one error, which have optimal rates, unless systematic perfect codes
exist. We also study the design of multi-error-correcting codes, and provide
two explicit constructions, one resulting in $[n+1,k+1,2t+2]$ systematic codes
with redundancy at most $2t+1$. We use non-constructive arguments to show the
existence of $[n,k,n-k]$-systematic codes for general parameters. Furthermore,
we prove that for rank modulation, systematic codes achieve the same capacity
as general error-correcting codes.
  Finally, in the $\ell_\infty$-metric we construct two $[n,k,d]$ systematic
multi-error-correcting codes, the first for the case of $d=O(1)$, and the
second for $d=\Theta(n)$. In the latter case, the codes have the same
asymptotic rate as the best codes currently known in this metric.


title:
Giant coercivity enhancement and dimensional crossover of
  superconductivity in Co2FeSi-NbN nanoscale bilayers

abstract:
  Proximity coupling and magnetic switching dynamics are shown to be correlated
in bilayers (B) of fully spin polarized ferromagnet (F) Co2FeSi and
superconductor (S) NbN. The upper critical field derived from resistivity
measurements shows a dimensional crossover with a reduced effective thickness
of the S layer. At temperatures (T) << superconducting Tc, the measured M-H
loops show two step switching; one at T-independent value ~ 7 Oe and other at
strongly T-dependent value becoming very large ~ 1 kOe at 2 K. These results
reveal induced ferromagnetism in S-layer at the S/F interface with vortex
pinning influenced dynamics.


title: Valuing FtD Contract under Copula Approach via Monte-Carlo Stimulation

abstract:
  This article aims to discuss some basics in field of credit modeling,
specifically the pricing issue of FtD contract. We demonstrate how the popular
copula approach is used in pricing FtD contract, and give a stimulation example
of such practice based on SAS 9.1.


title:
Is silicene stable in air? -- First principles study of oxygen
  adsorption and dissociation on silicene

abstract:
  The oxygen adsorption and dissociation on pristine silicene surface are
studied by use of first-principles in this letter. The oxygen adsorption and
dissociation on pristine silicene surface are studied by use of
first-principles in this letter. It is found that the pristine silicene is not
stable in air because the oxygen molecule can be easily adsorbed and
dissociated into two O atoms without overcoming any energy barrier on pristine
silicene surface. In addition, dissociated oxygen atoms are relatively
difficult to migrate on or desorbed from pristine silicene surface, leading to
poor mobility of oxygen atom. As a result, silicene would be changed into Si-O
compounds in air. The work will be helpful to reveal the detail of the
interaction between oxygen molecules and pristine silicene surface, especially
helpful to understand the stability of silicene in air.


title: Power Spectrum Density of long-term MAXI data

abstract:
  Monitor of All-sky X-ray Image (MAXI) on the International Space Station has
been observing the X-ray sky since 2009 August 15. It has accumulated the X-ray
data for about four years, so far. X-ray objects are usually variable and their
variability can be studied by the power spectrum density (PSD) of the X-ray
light curves.We applied our method to calculate PSDs of several kinds of
objects observed with MAXI. We obtained significant PSDs from 16 Seyfert
galaxies.For blackhole binary Cygnus X-1 there was a difference in the shape of
PSD between the hard state and the soft state. For high mass X-ray binaries,
Cen X-3, SMC X-1, and LMC X-4, there were several peaks in the PSD
corresponding to the orbital period and the superorbital period.


title:
Optimal Choice under Short Sell Limit with Sharpe Ratio as Criterion
  among Multiple Assets

abstract:
  This article is the term paper of the course Investments. We mainly focus on
modeling long-term investment decisions of a typical utility-maximizing
individual, with features of Chinese stock market in perspective. We adopt an
OR based methodology with market information as input parameters to carry out
the solution. Two main features of this article are: first, we take the no
short-sell constraint in Chinese stock market into consideration and use an
approach otherwise identical to Markowitz to work out the optimal portfolio
choice; this method has critical and practical implication to Chinese
investors. Second, we incorporate the benefits of multiple assets into one
single well-defined utility function and use a MIQP procedure to derive the
optimal allocation of funds upon each of them along the time-line.


title:
Graphene Nanoribbon Field-Effect Transistors on Wafer-Scale Epitaxial
  Graphene on SiC substrates

abstract:
  We report the realization of top-gated graphene nanoribbon field effect
transistors (GNRFETs) of ~10 nm width on large-area epitaxial graphene
exhibiting the opening of a band gap of ~0.14 eV. Contrary to prior
observations of disordered transport and severe edge-roughness effects of GNRs,
the experimental results presented here clearly show that the transport
mechanism in carefully fabricated GNRFETs is conventional band-transport at
room temperature, and inter-band tunneling at low temperature. The entire space
of temperature, size, and geometry dependent transport properties and
electrostatics of the GNRFETs are explained by a conventional thermionic
emission and tunneling current model. Our combined experimental and modeling
work proves that carefully fabricated narrow GNRs behave as conventional
semiconductors, and remain potential candidates for electronic switching
devices.


title:
High-Voltage Field Effect Transistors with Wide-Bandgap {\beta}-Ga2O3
  Nanomembranes

abstract:
  Nanoscale semiconductor materials have been extensively investigated as the
channel materials of transistors for energy-efficient low-power logic switches
to enable scaling to smaller dimensions. On the opposite end of transistor
applications is power electronics for which transistors capable of switching
very high voltages are necessary. Miniaturization of energy-efficient power
switches can enable the integration with various electronic systems and lead to
substantial boosts in energy efficiency. Nanotechnology is yet to have an
impact in this arena. In this work, it is demonstrated that nanomembranes of
the wide-bandgap semiconductor gallium oxide can be used as channels of
transistors capable of switching high voltages, and at the same time can be
integrated on any platform. The findings mark a step towards using lessons
learnt in nanomaterials and nanotechnology to address a challenge that yet
remains untouched by the field.


title:
Isolating quantum coherence with pathway-selective coherent
  multi-dimensional spectroscopy

abstract:
  Coherent coupling between spatially separated systems has long been explored
as a necessary requirement for quantum information and cryptography. Recent
discoveries suggest such phenomena appear in a much wider range of processes,
including light-harvesting in photosynthesis. These discoveries have been
facilitated by developments in coherent multi-dimensional spectroscopy (CMDS)
that allow interactions between different electronic states to be identified in
crowded spectra. For complex systems, however, spectral broadening and multiple
overlapping peaks limit the ability to separate, identify and properly analyse
all contributions. Here we demonstrate how pathway-selective CMDS can overcome
these limitations to reveal, isolate and allow detailed analysis of weak
coherent coupling between spatially separated excitons localised to different
semiconductor quantum wells. Selective excitation of the coherence pathways, by
spectrally shaping the laser pulses, provides access to previously hidden
details and enables quantitative analysis that can facilitate precise and
detailed understanding of interactions in this and other complex systems.


title:
Disentangling electronic and vibrational coherence in the
  Phycocyanin-645 light-harvesting complex

abstract:
  Energy transfer between chromophores in photosynthesis proceeds with near
unity quantum efficiency. Understanding the precise mechanisms of these
processes is made difficult by the complexity of the electronic structure and
interactions with different vibrational modes. Two-dimensional spectroscopy has
helped resolve some of the ambiguities and identified quantum effects that may
be important for highly efficient energy transfer. Many questions remain,
however, including whether the coherences observed are electronic and/or
vibrational in nature and what role they play. We utilise a two-colour
four-wave mixing experiment with control of the wavelength and polarization to
selectively excite specific coherence pathways. For the light-harvesting
complex PC645, from cryptophyte algae, we reveal and identify specific
contributions from both electronic and vibrational coherences and determine an
excited state structure based on two strongly-coupled electronic states and two
vibrational modes. Separation of the coherence pathways also uncovers the
complex evolution of these coherences and the states involved.


title:
Stellar Velocity Dispersion in Dissipative Galaxy Mergers with Star
  Formation

abstract:
  In order to better understand stellar dynamics in merging systems, such as
NGC 6240, we examine the evolution of central stellar velocity dispersion
(\sig) in dissipative galaxy mergers using a suite of binary disk merger
simulations that include feedback from stellar formation and active galactic
nuclei (AGNs). We find that $\sigma_*$ undergoes the same general stages of
evolution that were observed in our previous dissipationless simulations:
coherent oscillation, then phase mixing, followed by dynamical equilibrium. We
also find that measurements of $\sigma_*$ that are based only upon the youngest
stars in simulations consistently yield lower values than measurements based
upon the total stellar population. This finding appears to be consistent with
the so-called "$\sigma_*$ discrepancy," observed in real galaxies. We note that
quasar-level AGN activity is much more likely to occur when $\sigma_*$ is near
its equilibrium value rather than during periods of extreme $\sigma_*$.
Finally, we provide estimates of the scatter inherent in measuring $\sigma_*$
in ongoing mergers.


title: Local increase of symmetry on cooling in KNi$_2$Se$_2

abstract:
  KNi$_2$Se$_2$ exhibits an increase of symmetry on cooling below $T\le50$ K,
as observed by Raman spectroscopy and synchrotron x-ray diffraction. X-ray
absorption spectroscopy confirms that the symmetry increase is due to changes
in nickel-nickel interactions and suppression of charge density wave
fluctuations. Density functional theory calculations reveal a zone- boundary
lattice instability that provides a model of the room-temperature x-ray pair
distribution function data, but fails to describe the higher local symmetry
observed for $T\le50$K. Together, these results support many- body correlation
effects as drivers for the unusual heavy fermion electronic ground state in
KNi$_2$Se$_2$.


title:
Intense sub-2 cycle infrared pulse generation via phase mismatched
  cascaded nonlinear interaction in DAST crystal

abstract:
  Octave-spanning, 12.5 fs, (1.9 cycle) pulses with 115 {\mu}J energy in the
short-wavelength mid-infrared spectral range (1-2.5 {\mu}m) have been generated
via phase-mismatched cascaded nonlinear frequency conversion using organic DAST
crystal. Such ultra-fast cascading effect is ensured by the interaction of a
pump pulse with the exceptionally large effective nonlinearity of the DAST
crystal and experiencing non-resonant, strongly phase mismatched, Kerr-like
negative nonlinearity.


title: Parameterizing degree n polynomials by multipliers of periodic orbits

abstract:
  We present the following result: consider the space of complex polynomials of
degree n>2 with n-1 distinct marked periodic orbits of given periods. Then this
space is irreducible and the multipliers of the marked periodic orbits
considered as algebraic functions on the above mentioned space, are
algebraically independent over $\mathbb C$. Equivalently, this means that at
its generic point, the moduli space of degree n polynomial maps can be locally
parameterized by the multipliers of n-1 arbitrary distinct periodic orbits. A
detailed proof of this result (together with a proof of a more general
statement) is given in [arXiv:1305.0867]. In this exposition we substitute some
of the technical lemmas from [arXiv:1305.0867] with more geometric arguments.


title:
The discrete analogue of the differential operator $\frac{d^{2m}}{d
  x^{2m}} + 2\omega^2\frac{d^{2m-2}}{d x^{2m-2}} + \omega^4\frac{d^{2m-4}}{d
  x^{2m-4}}$

abstract:
  In the present paper we construct the discrete analogue $D_m(h\beta)$ of the
differential operator $\frac{d^{2m}}{d x^{2m}} + 2\omega^2\frac{d^{2m-2}}{d
x^{2m-2}} + \omega^4\frac{d^{2m-4}}{d x^{2m-4}}$. The discrete analogue
$D_m(h\beta)$ plays the main role in construction of optimal quadrature
formulas and interpolation splines minimizing the semi-norm in the $K_2(P_m)$
Hilbert space.


title:
The automorphism group of the Z_2-orbifold of the Barnes-Wall lattice
  vertex operator algebra of central charge 32

abstract:
  In this article, we prove that the full automorphism group of the
Z_2-orbifold of the Barnes-Wall lattice vertex operator algebra of central
charge 32 has the shape $2^{27}.E_6(2)$. In order to identify the group
structure, we introduce a graph structure on the Griess algebra and show that
it is a rank 3 graph associated to $E_6(2)$.


title:
New Proximity Estimate for Incremental Update of Non-uniformly
  Distributed Clusters

abstract:
  The conventional clustering algorithms mine static databases and generate a
set of patterns in the form of clusters. Many real life databases keep growing
incrementally. For such dynamic databases, the patterns extracted from the
original database become obsolete. Thus the conventional clustering algorithms
are not suitable for incremental databases due to lack of capability to modify
the clustering results in accordance with recent updates. In this paper, the
author proposes a new incremental clustering algorithm called CFICA(Cluster
Feature-Based Incremental Clustering Approach for numerical data) to handle
numerical data and suggests a new proximity metric called Inverse Proximity
Estimate (IPE) which considers the proximity of a data point to a cluster
representative as well as its proximity to a farthest point in its vicinity.
CFICA makes use of the proposed proximity metric to determine the membership of
a data point into a cluster.


title:
Obtaining imaginary weak values with a classical apparatus: applications
  for the time and frequency domains

abstract:
  Weak measurements with imaginary weak values are reexamined in light of
recent experimental results. The shift of the meter, due to the imaginary part
of the weak value, is derived via the probability of postselection, which
allows considering the meter as a distribution of a classical variable. The
derivation results in a simple relation between the change in the distribution
and its variance. By applying this relation to several experimental results, in
which the meter involved the time and frequency domains, it is shown to be
especially suitable for scenarios of that kind. The practical and conceptual
implications of a measurement method, which is based on this relation, are
discussed.


title:
Evidence of Multiple Slow Acoustic Oscillations in the Stellar Flaring
  Loops of Proxima Centauri

abstract:
  We present the first observational evidence of multiple slow acoustic
oscillations in the post flaring loops of the corona of Proxima Centauri using
XMM-Newton observations. We find the signature of periodic oscillations
localized in the decay phase of the flare in its soft (0.3-10.0 keV) X-ray
emissions. Using the standard wavelet tool, we find the multiple periodicities
of 1261 s and 687 s. These bursty oscillations persist for durations of 90
minutes and 50 minutes, respectively, for more than 4 cycles. The intensity
oscillations with the period of 1261 s may be the signature of the fundamental
mode of slow magnetoacoustic waves with the phase-speed of 119 km s$^{-1}$ in
the loop of the length 7.5$\times 10^{9}$ cm heated initially to obtain the
flare peak temperature of 33 MK and later cooled down in the decay phase
maintained at the average temperature of 7.2 MK. The other period of 687 s may
be associated with the first overtone of slow magnetoacoustic oscillations in
the flaring loop. The fundamental mode oscillations show a dissipation with
damping time of 47 min. The period ratio P$_{1}$/P$_{2}$ is found to be 1.83
indicating that such oscillations are most likely excited in longitudinal
density stratified stellar loops. We estimate the density scale height of
stellar loop system as 22.6 Mm, which is smaller than the hydrostatic scale
height of the hot loop system, and implies the existence of non-equilibrium
conditions.


title:
Experimental Proof of Universal Conductance Fluctuation in Quasi-1D
  Epitaxial Bi$_{2}$Se$_{3}$ Wires

abstract:
  We report on conductance fluctuation in quasi-one-dimensional wires made of
epitaxial Bi$_{2}$Se$_{3}$ thin film. We found that this type of fluctuation
decreases as the wire length becomes longer and that the amplitude of the
fluctuation is well scaled to the coherence, thermal diffusion, and wire
lengths, as predicted by conventional universal conductance fluctuation (UCF)
theory. Additionally, the amplitude of the fluctuation can be understood to be
equivalent to the UCF amplitude of a system with strong spin-orbit interaction
and no time-reversal symmetry. These results indicate that the conductance
fluctuation in Bi$_{2}$Se$_{3}$ wires is explainable through UCF theory. This
work is the first to verify the scaling relationship of UCF in a system with
strong spin-orbit interaction.


title: Measurement of a 127 keV Neutron Field with a micro-TPC Spectrometer

abstract:
  In order to measure the energy of neutron fields, with energy ranging from 8
keV to 1 MeV, a new primary standard is being developed at the IRSN (Institute
for Radioprotection and Nuclear Safety). This project, micro-TPC (Micro Time
Projection Chamber), carried out in collaboration with the LPSC (Laboratoire de
Physique Subatomique et de Cosmologie), is based on the nuclear recoil detector
principle. The instrument is presented with the associated method to measure
the neutron energy. This article emphasizes the proton energy calibration
procedure and energy measurements of a neutron field produced at 127 keV with
the IRSN facility AMANDE.


title: Suites of dwarfs around nearby giant galaxies

abstract:
  We consider a sample of the Updated Nearby Galaxy Catalog that contains eight
hundred objects within 11 Mpc. Environment of each galaxy was characterized by
a tidal index $\Theta_1$ depending on the separation and mass of the galaxy's
Main Disturber (=MD). We ascribed the UNGC galaxies with a common MD to its
suite, and ranked suite members according to their $\Theta_1$. All suite
members with positive $\Theta_1$ are assumed to be physical companions of the
MD. The distribution of suites by the number of members, n, follows to a
relation $N(n) \sim n^{-2}$. The twenty most populated suites contain 468
galaxies, i.e. 59% of the UNGC sample. About 58% of our sample are members of
physical groups. The fraction of MDs among the brightest galaxies is almost
100% and drops to 50% at $M_B = -18^m$. We discuss various properties of MDs,
as well as galaxies belonging to their suites. The suite abundance practically
does not depend on morphological type, linear diameter or hydrogen mass of MD,
revealing the tightest correlation with the MD dynamical mass. Dwarf galaxies
around MDs exhibit well-known segregation effects: the members of outskirts
have later morphological types, richer HI-contents and higher rates of star
formation activity. Nevertheless, there are some intriguing cases when dwarf
spheroidal galaxies occur at the far periphery of the suites, as well as some
late-type dwarfs residing close to MDs. The multiplicity of nearby groups
according to number of their physical members can be described by the
Hirsh-like index $h_g = 9$, indicating that the Local Volume contains 9 groups
with populations exceeding 9 members. (abridged)


title:
Search for the Higgs Boson: a Statistical Adventure of Exclusion and
  Discovery

abstract:
  The 40 years old Standard Model, the theory of particle physics, seems to
describe all experimental data very well. All of its elementary particles were
identified and studied apart from the Higgs boson until 2012. For decades many
experiments were built and operated searching for it, and finally, the two main
experiments of the Large Hadron Collider at CERN, CMS and ATLAS, in 2012
observed a new particle with properties close to those predicted for the Higgs
boson. In this talk we describe the search process: the exclusion of the Higgs
boson at LEP, the Large Electron Positron collider, and the observation at LHC
of a new boson with properties close to those predicted for the Higgs boson of
the Standard Model. We try to pay special attention on the statistical methods
used.


title: Self assembly of monodisperse CdS nano-cylinders with a pore

abstract:
  We present investigate the self assembly and growth of an array of $CdS$
nanotubes: a consequence of a fine balance of directed motion, diffusion and
aggregation of reacting ${\rm Cd^{+2}}$ and ${\rm S^{-2}}$ ions. In a previous
communication [J. Kiruthiga, A. Chatterji, J. Chem. Phys., {\bf 138} 024905
(2013)], we identified the mechanism of a unexpected growth of a very uniform
$CdS$ nano-cylinder from the end of a nano-channel. Furthermore, the cylinder
had a pore along the axis but were closed at one end. This unique phenomenon of
self assembly of {\em monodisperse} CdS nano-cylinders had been observed in a
rather simple experiment where two chambers containing 0.1 M ${\rm Cd Cl_2}$
and 0.1 M ${\rm Na_2 S}$ solutions were joined by an array of anodized
aluminium oxide (AAO) nano-channels [A. Varghese, S. Datta, Phys. Rev. E., {\bf
85}, 056104 (2012)]. Our previous study identified the principles governing the
growth of a single nano-tube at the exit point of a single AAO-nano-channel. In
this communication, we identify factors affecting the self-assembly process for
nano-tubes growing out an array of closely spaced AAO nano-channel exits. Our
model is not $Cd^{+2}$ or $S^{2-}$ specific, the experimental scheme can be
extended to self assemble a general class of reacting-diffusing A and B ions
with A (${\rm Cd^{+2}}$) selectively migrating out from a nano-channel. In
particular, we note that after the initial prolonged growth of nanotubes, there
can arise a severe deficiency of B-ions (${\rm S^{-2}}$) ions near the
AAO-nano-channel exits, the points where the reaction and aggregation occurs to
form the $CdS$ nanotube, thus impeding further growth of uniform CdS
nano-tubes. Thereby we predict the necessary characteristics of reacting
systems which can be self assembled using suitable adaptations of previous
experiments.


title: Double collinear splitting amplitudes at next-to-leading order

abstract:
  We compute the next-to-leading order (NLO) QCD corrections to the $1 \to 2$
splitting amplitudes in different dimensional regularization (DREG) schemes.
Besides recovering previously known results, we explore new DREG schemes and
analyze their consistency by comparing the divergent structure with the
expected behavior predicted by Catani's formula. Through the introduction of
scalar-gluons, we show the relation among splittings matrices computed using
different schemes. Also, we extended this analysis to cover the double
collinear limit of scattering amplitudes in the context of QCD+QED.


title: Variability of OI 090.4

abstract:
  OI 090.4 was monitored on 21 nights from 2006 to 2012 for studying the
variability. Strong variations occurred during the past 6 years. The long-term
variability amplitude is consistent with previous results. Microvariability was
analyzed for 43 intra-night light curves. 30 out of 43 light curves showed
microvariability by C and F tests analysis.


title:
Quenched decoherence in qubit dynamics due to strong amplitude-damping
  noise

abstract:
  We study non-perturbatively the time evolution of a qubit subject to
amplitude-damping noise. We show that at strong coupling the qubit decoherence
can be quenched owing to large environment feedbacks, such that the qubit can
evolve coherently even in the long-time limit. As an application, we show that
for a quantum channel that consists of two independent qubits subject to
uncorrelated local amplitude-damping noises, it can maintain at strong coupling
finite entanglement and better than classical teleportation fidelity at long
times.


title:
Fighting network space: it is time for an SQL-type language to filter
  phylogenetic networks

abstract:
  The search space of rooted phylogenetic trees is vast and a major research
focus of recent decades has been the development of algorithms to effectively
navigate this space. However this space is tiny when compared with the space of
rooted phylogenetic networks, and navigating this enlarged space remains a
poorly understood problem. This, and the difficulty of biologically
interpreting such networks, obstructs adoption of networks as tools for
modelling reticulation. Here, we argue that the superimposition of biologically
motivated constraints, via an SQL-style language, can both stimulate use of
network software by biologists and potentially significantly prune the search
space.


title: Boundary regularity for degenerate and singular parabolic equations

abstract:
  We characterise regular boundary points of the parabolic $p$-Laplacian in
terms of a family of barriers, both when $p>2$ and $1<p<2$. Due to the fact
that $p\not=2$, it turns out that one can multiply the $p$-Laplace operator by
a positive constant, without affecting the regularity of a boundary point. By
constructing suitable families of barriers, we give some simple geometric
conditions that ensure the regularity of boundary points.


title:
Fully Coupled Forward-Backward Stochastic Functional Differential
  Equations and Applications to Quadratic Optimal Control

abstract:
  In this paper, we consider the fully coupled forward-backward stochastic
functional differential equations (FBSFDEs) with stochastic functional
differential equations as the forward equations and the generalized anticipated
backward stochastic differential equations as the backward equations. We will
prove the existence and uniqueness theorem for FBSFDEs. As an application, we
deal with a quadratic optimal control problem for functional stochastic
systems, and get the explicit form of the optimal control by virtue of FBSFDEs.


title: IC3 Modulo Theories via Implicit Predicate Abstraction

abstract:
  We present a novel approach for generalizing the IC3 algorithm for invariant
checking from finite-state to infinite-state transition systems, expressed over
some background theories. The procedure is based on a tight integration of IC3
with Implicit (predicate) Abstraction, a technique that expresses abstract
tran- sitions without computing explicitly the abstract system and is
incremental with respect to the addition of predicates. In this scenario, IC3
operates only at the Boolean level of the abstract state space, discovering
inductive clauses over the abstraction predicates. Theory reasoning is confined
within the underlying SMT solver, and applied transparently when performing
satisfiability checks. When the current abstraction allows for a spurious
counterexample, it is refined by discov- ering and adding a sufficient set of
new predicates. Importantly, this can be done in a completely incremental
manner, without discarding the clauses found in the previous search. The
proposed approach has two key advantages. First, unlike current SMT gener-
alizations of IC3, it allows to handle a wide range of background theories
without relying on ad-hoc extensions, such as quantifier elimination or
theory-specific clause generalization procedures, which might not always be
available, and can moreover be inefficient. Second, compared to a direct
exploration of the concrete transition system, the use of abstraction gives a
significant performance improve- ment, as our experiments demonstrate.


title:
Bayesian inversion for the filtered flow at the Earth's Core Mantle
  Boundary

abstract:
  The inverse problem which consists of determining the flow at the Earth's
Core Mantle Boundary according to an outer core magnetic field and secular
variation model, has been investigated through a Bayesian formalism. To
circumvent the issue arising from the truncated nature of the available fields,
we combined two modelization methods. In the first step, we applied a filter on
the magnetic field to isolate its large scales by reducing the energy contained
in its small scales, we then derived the dynamical equation, referred as
filtered frozen flux equation, describing the spatio-temporal evolution of the
filtered part of the field. In the second step, we proposed a statistical
parametrization of the filtered magnetic field in order to account for both its
remaining unresolved scales and its large scale uncertainties. These two
modelization techniques were then included in the Bayesian formulation of the
inverse problem. To explore the complex posterior distribution of the velocity
field resulting from this development, we numerically implemented an algorithm
based on Markov Chain Monte Carlo methods. After evaluating our approach on
synthetic data and comparing it to previously introduced methods, we applied it
on real data for the single epoch 2005.0.


title:
The VMC Survey - X. Cepheids, RR Lyrae stars and binaries as probes of
  the Magellanic System's structure

abstract:
  The VMC survey is obtaining multi-epoch photometry in the Ks band of the
Magellanic System down to a limiting magnitude of Ks ~ 19.3 for individual
epoch data. The observations are spaced in time such as to provide optimal
sampling of the light curves for RR Lyrae stars and for Cepheids with periods
up to 20-30 days. We present examples of the Ks-band light curves of Classical
Cepheids and RR Lyrae stars we are obtaining from the VMC data and outline the
strategy we put in place to measure distances and infer the System
three-dimensional geometry from the variable stars. For this purpose the
near-infrared Period-Luminosity, Period-Wesenheit, and Period-Luminosity-Colour
relations of the system RR Lyrae stars and Cepheids are used. We extensively
exploit the catalogues of the Magellanic Clouds' variable stars provided by the
EROS-2 and OGLE III/IV microlensing surveys. By combining these surveys we
present the currently widest-area view of the Large Magellanic Cloud as
captured by the galaxy Cepheids, RR Lyrae stars and binaries. This reveals the
full extent of the main structures (bar/s - spiral arms) that have only been
vaguely guessed before. Our work strengthens the case for a detailed study of
the Large Magellanic Cloud three-dimensional geometry.


title:
An extended Petviashvili method for the numerical generation of
  traveling and localized waves

abstract:
  A family of fixed-point iterations is proposed for the numerical computation
of traveling waves and localized ground states. The methods are extended
versions of Petviashvili type, and they are applicable when the nonlinear term
of the system contains homogeneous functions of different degree. The methods
are described and applied to several examples of interest, that calibrate their
efficiency.


title: Using Extended Derksen Ideals in Computational Invariant Theory

abstract:
  The main purpose of this paper is to develop new algorithms for computing
invariant rings in a general setting. This includes invariants of nonreductive
groups but also of groups acting on algebras over certain rings. In particular,
we present an algorithm for computing invariants of a finite group acting on a
finitely generated algebra over a Euclidean ring. This may be viewed as a first
step in "computational arithmetic invariant theory." As a special case, the
algorithm can compute multiplicative invariant rings. Other algorithms are
applicable to nonreductive groups and are, when applied to reductive groups,
often faster than the algorithms known to date.
  The main tool is a generalized and modified version of an ideal that was
already used by Derksen in his algorithm for computing invariants of linearly
reductive groups. As a further application, these so-called extended Derksen
ideals give rise to invariantization maps, which turn an arbitrary ring element
into an invariant.
  For the most part, the algorithms of this paper have been implemented.


title:
Some aspects of harmonic analysis related to Gegenbauer expansions on
  the half-line

abstract:
  In this paper we consider the generalized shift operator, generated by the
Gegenbauer differential operator $$ G =\left(x^2-1\right)^{\frac{1}{2}-\lambda}
\frac{d}{dx} \left(x^2-1\right)^{\lambda+\frac{1}{2}}\frac{d}{dx}. $$ Maximal
function ($ G- $ maximal function), generated by the Gegenbauer differential
operator $ G $ is investigated. The $ L_{p,\lambda} $ -boundedness for the $ G-
$ maximal function is obtained. The concept of potential of Riesz-Gegenbauer is
introduced and for it the theorem of Sobolev type is proved.


title: Conjecture on the lateral growth of type I collagen fibrils

abstract:
  Type I collagen fibrils have circular cross sections with radii mostly
distributed in between 50 and 100 nm and are characterized by an axial banding
pattern with a period of 67 nm. The constituent long molecules of those
fibrils, the so-called triple helices, are densely packed but their nature is
such that their assembly must conciliate two conflicting requirements : a
double-twist around the axis of the fibril induced by their chirality and a
periodic layered organization, corresponding to the axial banding, built by
specific lateral interactions. We examine here how such a conflict could
contribute to the control of the radius of a fibril. We develop our analysis
with the help of two geometrical archetypes : the Hopf fibration and the
algorithm of phyllotaxis. The first one provides an ideal template for a
twisted bundle of fibres and the second ensures the best homogeneity and local
isotropy possible for a twisted dense packing with circular symmetry. This
approach shows that, as the radius of a fibril with constant double-twist
increases, the periodic layered organization can not be preserved without
moving from planar to helicoidal configurations. Such changes of configurations
are indeed made possible by the edge dislocations naturally present in the
phyllotactic pattern where their distribution is such that the lateral growth
of a fibril should stay limited in the observed range. Because of our limited
knowledge about the elastic constants involved, this purely geometrical
development stays at a quite conjectural level.


title: Deformation quantization of Leibniz algebras

abstract:
  This paper has two parts. The first part is a review and extension of the
methods of integration of Leibniz algebras into Lie racks, including as new
feature a new way of integrating 2-cocycles (see Lemma 3.9).
  In the second part, we use the local integration of a Leibniz algebra h using
a Baker-Campbell-Hausdorff type formula in order to deformation quantize its
linear dual h^*. More precisely, we define a natural rack product on the set of
exponential functions which extends to a rack action on C^{\infty}(h^*).


title:
Paraconformal structures, ordinary differential equations and totally
  geodesic manifolds

abstract:
  We construct point invariants of ordinary differential equations that
generalise the Cartan invariants of equations of order two and three. The
vanishing of the invariants is equivalent to the existence of a totally
geodesic paraconformal structure which consist of a paraconformal structure, an
adapted $GL(2,\R)$-connection and a two-parameter family of totally geodesic
hypersurfaces on the solution space. The structures coincide with the
projective structures in dimension 2 and with the Einstein-Weyl structures of
Lorentzian signature in dimension 3. We show that the totally geodesic
paraconformal structures in higher dimensions can be described by a natural
analogue of the Hitchin twistor construction. We present a general example of
Veronese webs which correspond to the hyper-CR Einstein-Weyl structures in
dimension 3. The Veronese webs are described by a hierarchy of integrable
systems.


title:
Charge order and possible bias-induced metastable state in the organic
  conductor \beta-(meso-DMBEDT-TTF)2PF6: effects of structural distortion

abstract:
  We theoretically investigate charge order and nonlinear conduction in a
quasi-two-dimensional organic conductor \beta-(meso-DMBEDT-TTF)2PF6
[DMBEDT-TTF=dimethylbis(ethylenedithio)tetrathiafulvalene]. Within the
Hartree-Fock approximation, we study effects of structural distortion on the
experimentally observed checkerboard charge order and its bias-induced melting
by using an extended Hubbard model with Peierls- and Holstein-types of
electron-lattice interactions. The structural distortion is important in
realizing the charge order. The current-voltage characteristics obtained by a
nonequilibrium Green's function method indicate that a charge-ordered
insulating state changes into a conductive state. Although the charge order and
lattice distortions are largely suppressed at a threshold voltage, they remain
finite even in the conductive state. We discuss the relevance of the results to
experimental observations, especially to a possible bias-induced metastable
state.


title: Limit theories and continuous orbifolds

abstract:
  Relativistic QFTs are in general defined by a collection of effective
actions, describing the dynamics of quantum fields at different energy scales.
The consequent natural idea of a space of theories is still a rather imprecise
notion, since a detailed knowledge or a classification of QFTs is out of reach.
In two dimensions the situation is in a better shape: in this context CFTs are
under control in many instances, and we know sequences of rational theories
emerging as end-points of RG flows. The present thesis explores the behaviour
of sequences of rational two-dimensional CFTs when the central charge
approaches its supremum. After a review of various notions useful to study
limit theories, like the concept of averaged fields and the construction of
continuous orbifolds, we analyse in detail the limit of sequences of N=2
supersymmetric CFTs that are connected by RG flows. The limit is not unique,
since with extended Virasoro symmetry one can choose different scalings for the
labels of the spectrum in the limit. We construct explicitly two c=3 CFTs
emerging as the large level limit of minimal models, and we identify both of
them: one is the N=2 CFT of two uncompactified free real bosons and two free
real fermions, the other is its continuous orbifold by U(1). We compare
spectrum, torus partition function, correlators and boundary conditions. The
neatest interpretation of this result is given by studying the realisation of
N=2 minimal models as gauged WZW models: taking the two different limits
amounts to zooming into two different regions of the target-space geometry. At
the end we speculate about possible extensions and generalisations.


title: Tunnelling methods and Unruh-DeWitt detectors in curved spacetimes

abstract:
  In this contribution we describe some interesting interplay between quantum
theory, general relativity and thermodynamics. In order to highlight the
connection between these theories, we describe two approaches that allow to
calculate thermal features as perceived by different observers in curved
spacetimes: the tunnelling method and the Unruh-DeWitt detector. In this
context, the semi-classical tunnelling approach is applied to the issue of
Hawking radiation and allows the calculation of the horizon temperature in a
wide variety of scenarios. The Unruh-DeWitt model is instead a quantum
field-theoretical approach that should give a more exact answer in terms of
transition rates between energy levels of an idealized detector.


title:
AGB nucleosynthesis at low metallicity: what can we learn from carbon-
  and s-elements-enhanced metal-poor stars

abstract:
  CEMP-s stars are very metal-poor stars with enhanced abundances of carbon and
s-process elements. They form a significant proportion of the very metal-poor
stars in the Galactic halo and are mostly observed in binary systems. This
suggests that the observed chemical anomalies are due to mass accretion in the
past from an asymptotic giant branch (AGB) star. Because CEMP-s stars have
hardly evolved since their formation, the study of their observed abundances
provides a way to probe our models of AGB nucleosynthesis at low metallicity.
To this end we included in our binary evolution model the results of the latest
models of AGB nucleosynthesis and we simulated a grid of 100,000 binary stars
at metallicity Z=0.0001 in a wide range of initial masses and separations. We
compared our modelled stars with a sample of 60 CEMP-s stars from the SAGA
database of metal-poor stars. For each observed CEMP-s star of the sample we
found the modelled star that reproduces best the observed abundances. The
result of this comparison is that we are able to reproduce simultaneously the
observed abundance of the elements affected by AGB nucleosynthesis (e.g. C, Mg,
s-elements) for about 60% of the stars in the sample.


title: An empirical clock to measure the dynamical age of stellar systems

abstract:
  Blue Straggler Stars (BSS) are among the brightest and more massive stars in
globular clusters (GCs). For this reason they represent an ideal tool to probe
the dynamical evolution of these stellar systems. Here I show, following the
results by Ferraro et al. (2012), that the BSS radial distribution can be used
as a powerful indicator of the cluster dynamical age. In fact on the basis of
their BSS radial distribution shape, GCs can be efficiently grouped in
different families corresponding to the different dynamical stages reached by
the stellar systems. This allows to define a first empirical clock, the
dynamical clock, able to measure the dynamical age of a stellar system from
pure observational quantities.


title: Geometric measure for two-qubit CS-states: an exactly solvable model

abstract:
  Newly, during an analytical calculation M. A. Yurischev [arXiv: 1302.5239
(2013)] prove that quantum discord (or entanglement) remains unchangeable for
any centrosymmetric (CS) states that are converted to their corresponding mode
X. In this paper, in addition to the above calculations, the conditions which
geometric measure remains constant are presented. This work will be completed
with discussion about two physical examples.


title:
Minimax solutions for a problem with sign changing nonlinearity and lack
  of strict convexity

abstract:
  A result of existence of a nonnegative and a nontrivial solution is proved
via critical point theorems for non smooth functionals. The equation considered
presents a convex part and a nonlinearity which changes sign.


title:
Rapid and reliable thickness identification of two-dimensional
  nanosheets using optical microscopy

abstract:
  The physical and electronic properties of ultrathin two-dimensional (2D)
layered nanomaterials are highly related to their thickness. Therefore, the
rapid and accurate identification of single- and few- to multi-layer nanosheets
is essential to their fundamental study and practical applications. Here, a
universal optical method has been developed for simple, rapid and reliable
identification of single- to quindecuple-layer (1L-15L) 2D nanosheets,
including graphene, MoS2, WSe2 and TaS2, on Si substrates coated with 90 nm or
300 nm SiO2. The optical contrast differences between the substrates and 2D
nanosheets with different layer numbers were collected and tabulated, serving
as a standard reference, from which the layer number of a given nanosheet can
be readily and reliably determined without using complex calculation nor
expensive instrument. Our general optical identification method will facilitate
the thickness-dependent study of various 2D nanomaterials, and expedite their
research toward practical applications.


title: $\phi N$ photoproduction coupled with the $K\Lambda^*$ channel

abstract:
  We present in this talk a recent investigation on $\phi$ photoproduction,
emphasizing the rescattering effects of the $K\Lambda^*$ channel near the
threshold region. We discuss the results of the differential cross section and
the angular distributions.


title:
A SINFONI Integral Field Spectroscopy Survey for Galaxy Counterparts to
  Damped Lyman-alpha Systems - V. Neutral and Ionised Phase Metallicities

abstract:
  The gas-phase and stellar metallicities have proven to be important
parameters to constrain the star formation history of galaxies. However, HII
regions associated with recent star-formation may not have abundances typical
for the galaxy as a whole and it is believed that the bulk of the metals may be
contained in the neutral gas. It is therefore important to directly probe the
metal abundances in the neutral gas, which can be done by using absorption
lines imprinted on a background quasar. Recently, we have presented studies of
the stellar content of a small sample of such quasar absorbers with HI column
densities measured to be in the sub-Damped Lyman-alpha to Damped Lyman-alpha
range. Here, we present observations covering 300 nm to 2.5 microns of emission
line spectra of three of these absorbing-galaxies using the long-slit
spectrograph X-Shooter on the VLT. This allows us to compare the neutral and
ionised phase metallicities in the same objects and relates these measures to
possible signature of low-metallicity gas accretion or outflows of gas enriched
by star formation. Our results suggest that the abundances derived in
absorption along the line-of-sight to background quasars are reliable measures
of the overall galaxy metallicities. In addition to a comparison of abundances
in different phases of the gas, a potential observational consequence of
differences in fueling mechanisms for disc galaxies is the internal
distribution of their chemical abundances. We present some evidence for small
negative metallicity gradients in the three systems. The flat slopes are in
line with the differences observed between the two phases of the gas. These
results suggest that a comparison of the HI and HII metallicities is a robust
indicator of abundance gradients in high-redshift galaxies and do not favour
the presence of infall of fresh gas in these objects.


title:
Novel Scintillating Materials Based on Phenyl-Polysiloxane for Neutron
  Detection and Monitoring

abstract:
  Neutron detectors are extensively used at many nuclear research facilities
across Europe. Their application range covers many topics in basic and applied
nuclear research: in nuclear structure and reaction dynamics (reaction
reconstruction and decay studies); in nuclear astrophysics (neutron emission
probabilities); in nuclear technology (nuclear data measurements and
in-core/off-core monitors); in nuclear medicine (radiation monitors,
dosimeters); in materials science (neutron imaging techniques); in homeland
security applications (fissile materials investigation and cargo inspection).
Liquid scintillators, widely used at present, have however some drawbacks given
by toxicity, flammability, volatility and sensitivity to oxygen that limit
their duration and quality. Even plastic scintillators are not satisfactory
because they have low radiation hardness and low thermal stability. Moreover
organic solvents may affect their optical properties due to crazing. In order
to overcome these problems, phenyl-polysiloxane based scintillators have been
recently developed at Legnaro National Laboratory. This new solution showed
very good chemical and thermal stability and high radiation hardness. The
results on the different samples performance will be presented, paying special
attention to a characterization comparison between synthesized phenyl
containing polysiloxane resins where a Pt catalyst has been used and a
scintillating material obtained by condensation reaction, where tin based
compounds are used as catalysts. Different structural arrangements as a result
of different substituents on the main chain have been investigated by High
Resolution X-Ray Diffraction, while the effect of improved optical
transmittance on the scintillation yield has been elucidated by a combination
of excitation/fluorescence measurements and scintillation yield under exposure
to alpha and {\gamma}-rays.


title:
Effect of the disorder in graphene grain boundaries: A wave packet
  dynamics study

abstract:
  Chemical vapor deposition (CVD) on Cu foil is one of the most promising
methods to produce graphene samples despite of introducing numerous grain
boundaries into the perfect graphene lattice. A rich variety of GB structures
can be realized experimentally by controlling the parameters in the CVD method.
Grain boundaries contain non-hexagonal carbon rings (4,5,7,8 membered rings)
and vacancies in various ratios and arrangements. Using wave packet dynamic
(WPD) simulations and tight-binding electronic structure calculations, we have
studied the effect of the structure of GBs on the transport properties. Three
model GBs with increasing disorder were created in the computer: a periodic 5-7
GB, a "serpentine" GB, and a disordered GB containing 4,8 membered rings and
vacancies. It was found that for small energies (E=EF+-1eV) the transmission
decreases with increasing disorder. Four membered rings and vacancies are
identified as the principal scattering centres. Revealing the connection
between the properties of GBs and the CVD growth method may open new
opportunities in the graphene based nanoelectronics.


title: Effective Einstein Cosmological Spaces for Non-Minimal Modified Gravity

abstract:
  Certain off-diagonal vacuum and nonvacuum configurations in Einstein gravity
can mimic physical effects of modified gravitational theories of $
f(R,T,R_{\mu\nu}T^{\mu\nu})$ type. We prove this statement by constructing
exact and approximate solutions which encode certain models of covariant Ho\v
rava type gravity with dynamical Lorentz symmetry breaking. Off-diagonal
generalizations of de Sitter and nonolonomic $\Lambda$CDM universes are
constructed which are generated through nonlinear gravitational polarization of
fundamental physical constants and which model interactions with non-constant
exotic fluids and effective matter. The problem of possible matter instability
for such off-diagonal deformations in (modified) gravity theories is discussed.


title:
Paracontrolled Distributions and the 3-dimensional Stochastic
  Quantization Equation

abstract:
  We prove the existence and uniqueness of a local solution to the periodic
renormalized $\Phi^4_3$ model of stochastic quantisation using the method of
controlled distributions introduced recently by Imkeller, Gubinelli and
Perkowski ("Paraproducts, rough paths and controlled distributions",
arXiv:1210.2684)


title:
Joint Wireless Information and Energy Transfer in a K-User MIMO
  Interference Channel

abstract:
  Recently, joint wireless information and energy transfer (JWIET) methods have
been proposed to relieve the battery limitation of wireless devices. However,
the JWIET in a general K-user MIMO interference channel (IFC) has been
unexplored so far. In this paper, we investigate for the first time the JWIET
in K-user MIMO IFC, in which receivers either decode the incoming information
data (information decoding, ID) or harvest the RF energy (energy harvesting,
EH). In the K-user IFC, we consider three different scenarios according to the
receiver mode -- i) multiple EH receivers and a single ID receiver, ii)
multiple IDs and a single EH, and iii) multiple IDs and multiple EHs. For all
scenarios, we have found a common necessary condition of the optimal
transmission strategy and, accordingly, developed the transmission strategy
that satisfies the common necessary condition, in which all the transmitters
transferring energy exploit a rank-one energy beamforming. Furthermore, we have
also proposed an iterative algorithm to optimize the covariance matrices of the
transmitters that transfer information and the powers of the energy beamforming
transmitters simultaneously, and identified the corresponding achievable
rate-energy tradeoff region. Finally, we have shown that by selecting EH
receivers according to their signal-to-leakage-and-harvested energy-ratio
(SLER), we can improve the achievable rate-energy region further.


title:
Voltage noise, switching rates, and multiple phase-slips in moderately
  damped Josephson junctions

abstract:
  We study the voltage noise properties including the switching rates and
statistics of phase-slips in moderately damped Josephson junctions using a
novel efficient numerical approach combining the matrix continued-fraction
method with the full counting statistics. By analyzing the noise results
obtained for the RCSJ model we identify different dominating components, namely
the thermal noise close to equilibrium (small current-bias regime), the shot
noise of (multiple) phase-slips in the intermediate range of biases and the
switching noise for yet higher bias currents. We extract thus far inaccessible
characteristic rates of phase-slips in the shot noise regime as well as the
escape and retrapping rates in the switching regime as functions of various
junction's parameters. The method can be extended and applied to other
experimentally relevant Josephson junction circuits.


title:
Density Functional Theory and Generalized Tight-Binding combined method
  for Hubbard fermion-phonon coupling study in strongly correlated LSCO-system

abstract:
  We present ab initio results for the electron-phonon interaction of the
\Gamma-point phonons in the tetragonal high-temperature phase of La2CuO4.
Eigenfrequencies and eigenvectors for the symmetry-allowed phonon modes are
calculated with the full-potential augmented plane wave+local orbitals method
using the frozen phonon approach. It is found that the \Gamma-point phonons
with the strongest electron-phonon interaction are the A{2u} modes with 236
cm^{-1}, 131 cm^{-1} and 476 cm^{-1}. To take effect of strong electron on-site
interaction into account we use generalized tight-binding method that results
in the interaction of phonons with Hubbard fermions forming quasiparticle's
band structure. Finally, the matrix elements of Hubbard fermion-phonon
interaction and their reduction due to strong electron correlation are
obtained.


title: Double Cascade Model of Financial Crises

abstract:
  The scope of financial systemic risk research encompasses a wide range of
interbank channels and effects, including asset correlation shocks, default
contagion, illiquidity contagion, and asset fire sales. This paper introduces a
financial network model that combines the default and liquidity stress
mechanisms into a "double cascade mapping". The progress and eventual result of
the crisis is obtained by iterating this mapping to its fixed point. Unlike
simpler models, this model can therefore quantify how illiquidity or default of
one bank influences the overall level of liquidity stress and default in the
system. Large-network asymptotic cascade mapping formulas are derived that can
be used for efficient network computations of the double cascade. Numerical
experiments then demonstrate that these asymptotic formulas agree qualitatively
with Monte Carlo results for large finite networks, and quantitatively except
when the initial system is placed in an exceptional "knife-edge" configuration.
The experiments clearly support the main conclusion that when banks respond to
liquidity stress by hoarding liquidity, then in the absence of asset fire
sales, the level of defaults in a financial network is negatively related to
the strength of bank liquidity hoarding and the eventual level of stress in the
network.


title: Quantitative results for Halpern iterations of nonexpansive mappings

abstract:
  We give a rate of metastability for Halpern's iteration relative to a rate of
metastability for the resolvent for nonexpansive mappings in uniformly smooth
Banach spaces, extracted from a proof due to Xu. In Hilbert space, the latter
is known, so we get an explicit rate of metastability. We also extract a rate
of asymptotic regularity for general normed spaces. Such rates have already
been extracted by Kohlenbach and Leu\c{s}tean for different and incomparable
conditions on $(\lambda_n)$. The proof analyzed in this paper is also more
effective than the proofs treated by Kohlenbach and Leu\c{s}tean in that it
does not use Banach limits or weak compactness, which makes the extraction
particularly efficient. Moreover, we also give an equivalent axiomatization of
uniformly smooth Banach spaces. This paper is part of an ongoing case study of
proof mining in nonlinear fixed point theory.


title:
The effect of a micro bubble dispersed gas phase on hydrogen isotope
  transport in liquid metals under nuclear irradiation

abstract:
  The present work intend to be a first step towards the understanding and
quantification of the hydrogen isotope complex phenomena in liquid metals for
nuclear technology. Liquid metals under nuclear irradiation in,e.g., breeding
blankets of a nuclear fusion reactor would generate tritium which is to be
extracted and recirculated as fuel. At the same time that tritium is bred,
helium is also generated and may precipitate in the form of nano bubbles. Other
liquid metal systems of a nuclear reactor involve hydrogen isotope absorption
processes, e.g., tritium extraction system. Hence, hydrogen isotope absorption
into gas bubbles modelling and control may have a capital importance regarding
design, operation and safety.
  Here general models for hydrogen isotopes transport in liquid metal and
absorption into gas phase, that do not depend on the mass transfer limiting
regime, are exposed and implemented in OpenFOAMR CFD tool for 0D to 3D
simulations. Results for a 0D case show the impact of a He dispersed phase of
nano bubbles on hydrogen isotopes inventory at different temperatures as well
as the inventory evolution during a He nucleation event. In addition, 1D and 2D
axisymmetric cases are exposed showing the effect of a He dispersed gas phase
on hydrogen isotope permeation through a lithium lead eutectic alloy and the
effect of vortical structures on hydrogen isotope transport at a backward
facing step. Exposed results give a valuable insight on current nuclear
technology regarding the importance of controlling hydrogen isotope transport
and its interactions with nucleation event through gas absorption processes.
  Keywords: hydrogen isotopes, permeation, two-phase flow, nucleation, CFD


title:
Application of Fourier and Wavelet Transform for analysing 300 years
  Sunspot numbers to Explain the Solar Cycles

abstract:
  In this paper Fourier Transform and Wavelet Transform are applied in case of
recent 300 years of sunspot numbers to explain the solar cycles. Here basically
parallel study of Fourier and Wavelet analysis are done and we have observed
that the better result can be obtained from Wavelet analysis during sunspot
number analysis. We are able to show various minima and maxima in the recent
ages of solar cycles with this tool. The exact periodicity and other possible
periodicities in the cyclic phenomenon of sunspot activity are determined.


title: Herwig++ 2.7 Release Note

abstract:
  A new release of the Monte Carlo event generator Herwig++ (version 2.7) is
now available. This version comes with a number of improvements including: an
interface to the Universal FeynRules Output (UFO) format allowing the
simulation of a wide range of new-physics models; developments of the Matchbox
framework for next-to-leading order (NLO) simulations; better treatment of QCD
radiation in heavy particle decays in new-physics models; a new tune of
underlying event and colour connection parameters that allows a good
simultaneous description of both Tevatron and LHC underlying event data and the
effective cross-section parameter for double-parton scattering.


title:
Splitting Valleys in Si/SiO$_2$: Identification and Control of Interface
  States

abstract:
  Interface states in a silicon/barrier junction break the silicon valley
degeneracy near the interface, a desirable feature for some Si quantum
electronics applications. Within a minimal multivalley tight-binding model in
one dimension, we inspect here the spatial extent of these states into the Si
and the barrier materials, as well as favorable conditions for its spontaneous
formation. Our approach---based on Green's-function renormalization-decimation
techniques---is asymptotically exact for the infinite chain and shows the
formation of these states regardless of whether or not a confining electric
field is applied. The renormalization language naturally leads to the central
role played by the chemical bond of the atoms immediately across the interface.
In the adopted decimation procedure, the convergence rate to a fixed point
directly relates the valley splitting and the spread of the wave function,
consequently connecting the splitting to geometrical experimental parameters
such as the capacitance of a two-dimensional electron gas---explicitly
calculated here. This should serve as a probe to identify such states as a
mechanism for enhanced valley splitting.


title: Non-vanishing Berry Phase in Chiral Insulators

abstract:
  The binary compounds FeSi, RuSi, and OsSi are chiral insulators crystallizing
in the space group P2_13 which is cubic. By means of ab initio calculations we
find for these compounds a non-vanishing electronic Berry phase, the sign of
which depends on the handedness of the crystal. There is thus the possibility
that the Berry phase signals the existence of a macroscopic electric
polarization due to the electrons. We show that this is indeed so if a small
external magnetic field is applied in the [111]-direction. The electric
polarization is oscillatory in the magnetic field and possesses a signature
that distinguishes the handedness of the crystal. Our findings add to the
discussion of topological classifications of insulators and are significant for
spintronics applications, and in particular, for a deeper understanding of
skyrmions in insulators.


title: Capacity Analysis of IEEE 802.11ah WLANs for M2M Communications

abstract:
  Focusing on the increasing market of the sensors and actuators networks, the
IEEE 802.11ah Task Group is currently working on the standardization of a new
amendment. This new amendment will operate at the sub-1GHz band, ensure
transmission ranges up to 1 Km, data rates above 100 kbps and very low power
operation. With IEEE 802.11ah, the WLANs will offer a solution for applications
such as smart metering, plan automation, eHealth or surveillance. Moreover,
thanks to a hierarchical signalling, the IEEE 802.11ah will be able to manage a
higher number of stations (STAs) and improve the 802.11 Power Saving
Mechanisms. In order to support a high number of STAs, two different signalling
modes are proposed, TIM and Non-TIM Offset. In this paper we present a
theoretical model to predict the maximum number of STAs supported by both modes
depending on the traffic load and the data rate used. Moreover, the IEEE
802.11ah performance and energy consumption for both signalling modes and for
different traffic patterns and data rates is evaluated. Results show that both
modes achieve similar Packet Delivery Ratio values but the energy consumed with
the TIM Offset is, in average, a 11.7% lower.


title:
Invariant curves for exact symplectic twist maps of the cylinder with
  Bryuno rotation numbers

abstract:
  Since Moser's seminal work it is well known that the invariant curves of
smooth nearly integrable twist maps of the cylinder with Diophantine rotation
number are preserved under perturbation. In this paper we show that, in the
analytic class, the result extends to Bryuno rotation numbers. First, we will
show that the series expansion for the invariant curves in powers of the
perturbation parameter can be formally defined, then we shall prove that the
series converges absolutely in a neighbourhood of the origin. This will be
achieved using multiscale analysis and renormalisation group techniques to
express the coefficients of the series as sums of values which are represented
graphically as tree diagrams and then exploit cancellations between terms
contributing to the same perturbation order. As a byproduct we shall see that,
when perturbing linear maps, the series expansion for an analytic invariant
curve converges for all perturbations if and only if the corresponding rotation
number satisfies the Bryuno condition.


title: Singularities with respect to Mather-Jacobian discrepancies

abstract:
  As is well known, the "usual discrepancy" is defined for a normal
Q-Gorenstein variety. By using this discrepancy we can define a canonical
singularity and a log canonical singularity. In the same way, by using a new
notion, Mather-Jacobian discrepancy introduced in recent papers we can define a
"canonical singularity" and a "log canonical singularity" for not necessarily
normal or Q-Gorenstein varieties. In this paper, we show basic properties of
these singularities, behavior of these singularities under deformations and
determine all these singularities of dimension up to 2.


title: Domain wall motion in ferromagnetic nanotubes: Analytic results

abstract:
  Dynamics of magnetization domain walls (DWs) in thin ferromagnetic nanotubes
subject to longitudinal external fields is addressed analytically in the
regimes of strong and weak penalization. Explicit functional forms of the DW
profiles and formulas for the DW propagation velocity are derived in both
regimes. In particular, the DW speed is shown to depend nonlinearly on the
nanotube radius.


title: Algebraic Characters of Harish-Chandra Modules and Arithmeticity

abstract:
  These are expanded notes from lectures at the Workshop "Representation Theory
and Applications" held at Yeditepe University, Istanbul, in honor of Roger E.
Howe. They are supplemented by the application of algebraic character theory to
the construction of Galois-equivariant characters for Harish-Chandra modules.


title: Quasielastic contribution to antineutrino-nucleus scattering

abstract:
  We report on a calculation of cross sections for charged-current quasielastic
antineutrino scattering off $^{12}$C in the energy range of interest for the
MiniBooNE experiment. We adopt the impulse approximation (IA) and use the
nonrelativistic continuum random phase approximation (CRPA) to model the
nuclear dynamics. An effective nucleon-nucleon interaction of the Skyrme type
is used. We compare our results with the recent MiniBooNE antineutrino
cross-section data and confront them with alternate calculations. The CRPA
predictions reproduce the gross features of the shape of the measured
double-differential cross sections. The CRPA cross sections are typically
larger than those of other reported IA calculations but tend to underestimate
the magnitude of the MiniBooNE data. We observe that an enhancement of the
nucleon axial mass in CRPA calculations is an effective way of improving on the
description of the shape and magnitude of the double-differential cross
sections. The rescaling of $M_{A}$ is illustrated to affect the shape of the
double-differential cross sections differently than multinucleon effects beyond
the IA.


title:
Nucleation, growth and transport modelling of helium bubbles under
  nuclear irradiation in lead-lithium with the Self-consistent nucleation
  theory and surface tension corrections

abstract:
  Helium (He) nucleation in liquid metal breeding blankets of a DT fusion
reactor may have a significant impact regarding system design, safety and
operation. Large He production rates are expected due to tritium (T) fuel
self-sufficiency requirement, as both, He and T, are produced at the same rate.
Low He solubility, local high concentrations, radiation damage and fluid
discontinuities, among other phenomena, may yield the necessary conditions for
He nucleation. Hence, He nucleation may have a significant impact on T
inventory and may lower the T breeding ratio.
  A model based on the self-consistent nucleation theory (SCT) with a surface
tension curvature correction model has been implemented in OpenFoam(r) CFD
code. A modification through a single parameter of the necessary nucleation
condition is proposed in order to take into account all the nucleation
triggering phenomena, specially radiation induced nucleation. Moreover, the
kinetic growth model has been adapted so as to allow for the transition from a
critical cluster to a macroscopic bubble with a diffusion growth process.
  Limitations and capabilities of the models are shown by means of
zero-dimensional simulations and sensitivity analyses to key parameters under
HCLL breeding unit conditions. Results provide a good qualitative insight into
the helium nucleation phenomenon in LM systems for fusion technology and
reinforces the idea that nucleation may not be a remote phenomenon, may have a
large impact on the system's design and reveals the necessity to conduct
experiments on He cavitation.


title:
Bin Packing and Related Problems: General Arc-flow Formulation with
  Graph Compression

abstract:
  We present an exact method, based on an arc-flow formulation with side
constraints, for solving bin packing and cutting stock problems --- including
multi-constraint variants --- by simply representing all the patterns in a very
compact graph. Our method includes a graph compression algorithm that usually
reduces the size of the underlying graph substantially without weakening the
model. As opposed to our method, which provides strong models, conventional
models are usually highly symmetric and provide very weak lower bounds.
  Our formulation is equivalent to Gilmore and Gomory's, thus providing a very
strong linear relaxation. However, instead of using column-generation in an
iterative process, the method constructs a graph, where paths from the source
to the target node represent every valid packing pattern.
  The same method, without any problem-specific parameterization, was used to
solve a large variety of instances from several different cutting and packing
problems. In this paper, we deal with vector packing, graph coloring, bin
packing, cutting stock, cardinality constrained bin packing, cutting stock with
cutting knife limitation, cutting stock with binary patterns, bin packing with
conflicts, and cutting stock with binary patterns and forbidden pairs. We
report computational results obtained with many benchmark test data sets, all
of them showing a large advantage of this formulation with respect to the
traditional ones.