title:
Stability estimates for an inverse problem for the magnetic
  Schr\"odinger operator

abstract:
  In this paper we prove stable determination of an inverse boundary value
problem associated to a magnetic Schr\"odinger operator assuming that the
magnetic and electric potentials are essentially bounded and the magnetic
potentials admit a H\"older-type modulus of continuity in the sense of $L^2$.


title:
Vortex polygons and their stabilities in Bose-Einstein condensates and
  field theory

abstract:
  We study vortex polygons and their stabilities in miscible two-component
Bose-Einstein condensates, and find that vortex polygons are stable for the
total circulation $Q \leq 5$, metastable for $Q = 6$, and unstable for $Q \geq
7$. As a related model in high-energy physics, we also study the vortex polygon
of the baby-Skyrme model with an anti-ferromagnetic potential term, and compare
both results.


title:
Cosmic Ray Parallel and Perpendicular Transport in Turbulent Magnetic
  Fields

abstract:
  A correct description of cosmic-ray (CR) diffusion in turbulent plasma is
essential for many astrophysical and heliospheric problems. This paper aims to
present physical diffusion behavior of CRs in actual turbulent magnetic fields,
model of which has been numerically tested. We perform test particle
simulations in compressible magnetohydrodynamic turbulence. We obtain
scattering and spatial diffusion coefficients by tracing particle trajectories.
We find no resonance gap for pitch-angle scattering at 90$^\circ$. Our result
confirms the dominance of mirror interaction with compressible modes for most
pitch angles as revealed by the nonlinear theory. For cross-field transport,
our results are consistent with normal diffusion predicted earlier for large
scales. The diffusion behavior strongly depends on the Alfvenic Mach number and
particle's parallel mean free path. We, for the first time, numerically derive
the dependence of M_A^4 for perpendicular diffusion coefficient with respect to
the mean magnetic field. We conclude that CR diffusion coefficients are
anisotropic in sub-Alfvenic turbulence and spatially correlated to the local
turbulence properties. On scales smaller than the injection scale, we find that
CRs are superdiffusive. We emphasize the importance of our results in a wide
range of astrophysical processes, including magnetic reconnection.


title: Handbook of LHC Higgs Cross Sections: 3. Higgs Properties

abstract:
  This Report summarizes the results of the activities in 2012 and the first
half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the
working group was to present the state of the art of Higgs Physics at the LHC,
integrating all new results that have appeared in the last few years. This
report follows the first working group report Handbook of LHC Higgs Cross
Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group
report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions
(CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012
this report focuses on refined prediction of Standard Model (SM) Higgs
phenomenology around the experimentally observed value of 125-126 GeV, refined
predictions for heavy SM-like Higgs bosons as well as predictions in the
Minimal Supersymmetric Standard Model and first steps to go beyond these
models. The other main focus is on the extraction of the characteristics and
properties of the newly discovered particle such as couplings to SM particles,
spin and CP-quantum numbers etc.


title: Making simple proofs simpler

abstract:
  An open partition \pi{} [Cod09a, Cod09b] of a tree T is a partition of the
vertices of T with the property that, for each block B of \pi, the upset of B
is a union of blocks of \pi. This paper deals with the number, NP(n), of open
partitions of the tree, V_n, made of two chains with n points each, that share
the root.


title:
Probing top quark electromagnetic dipole moments in
  single-top-plus-photon production

abstract:
  The production of a single top quark in association with an isolated photon
probes the electromagnetic coupling structure of the top quark. We investigate
the sensitivity of kinematical distributions at the LHC in
single-top-plus-photon production in view of a detection of anomalous electric
and magnetic dipole moments of the top quark.


title: Quantum state transfer and Hadamard gate for coherent states

abstract:
  We propose a quantum state transfer from an atomic qubit to a cat-like qubit
by means of one degenerate Raman interaction and one Hadamard gate operation
for coherent states. We show that the coefficients of the atomic qubit can be
mapped onto coherent state qubit, with an effective qubit state transfer.


title: Fate of density functional theory in high-pressure solid hydrogen

abstract:
  This paper investigates some of the successes and failures of density
functional theory in the study of high-pressure solid hydrogen at low
temperature. We calculate the phase diagram, metallization pressure, phonon
spectrum, and proton zero-point energy using three popular exchange-correlation
functionals: the local density approximation (LDA), the Perdew-Burke-Ernzerhof
(PBE) generalized gradient approximation, and the semi-local
Becke-Lee-Yang-Parr (BLYP) functional. We focus on the solid molecular
P$6_3$/m, C2/c, Cmca-12, and Cmca structures in the pressure range from
$100<P<500$ GPa over which phases I, II and III are observed experimentally. At
the static level of theory, in which proton zero-point energy is ignored, the
LDA, PBE and BLYP functionals give very different structural transition and
metallization pressures, with the BLYP phase diagram in better agreement with
experiment. Nevertheless, all three functionals provide qualitatively the same
information about the band gaps of the four structures and the phase
transitions between them. Going beyond the static level, we find that the
frequencies of the vibron modes observed above 3000 cm$^{-1}$ depend strongly
on the choice of exchange-correlation functional, although the low-frequency
part of the phonon spectrum is little affected. The largest and smallest values
of the proton zero-point energy, obtained using the BLYP and LDA functionals,
respectively, differ by more than 10 meV/proton. Including the proton
zero-point energy calculated from the phonon spectrum within the harmonic
approximation improves the agreement of the BLYP and PBE phase diagrams with
experiment. Taken as a whole, our results demonstrate the inadequacy of
mean-field-like density functional calculations of solid molecular hydrogen in
phases I, II and III and emphasize the need for more sophisticated methods.


title: A Mathematica package to cope with partially ordered sets

abstract:
  Mathematica offers, by way of the package Combinatorics, many useful
functions to work on graphs and ordered structures, but none of these functions
was specific enough to meet the needs of our research group. Moreover, the
existing functions are not always helpful when one has to work on new concepts.
  In this paper we present a package of features developed in Mathematica which
we consider particularly useful for the study of certain categories of
partially ordered sets. Among the features offered, the package includes: (1)
some basic features to treat partially ordered sets; (2) the ability to
enumerate, create, and display monotone and regular partitions of partially
ordered sets; (3) the capability of constructing the lattices of partitions of
a poset, and of doing some useful computations on these structures; (4) the
possibility of computing products and coproducts in the category of partially
ordered sets and monotone maps; (5) the possibility of computing products and
coproducts in the category of forests (disjoint union of trees) and open maps
(cf. [DM06] for the product between forests).


title:
One Hierarchy Spawns Another: Graph Deconstructions and the Complexity
  Classification of Conjunctive Queries

abstract:
  We study the problem of conjunctive query evaluation relative to a class of
queries; this problem is formulated here as the relational homomorphism problem
relative to a class of structures A, wherein each instance must be a pair of
structures such that the first structure is an element of A. We present a
comprehensive complexity classification of these problems, which strongly links
graph-theoretic properties of A to the complexity of the corresponding
homomorphism problem. In particular, we define a binary relation on graph
classes, which is a preorder, and completely describe the resulting hierarchy
given by this relation. This relation is defined in terms of a notion which we
call graph deconstruction and which is a variant of the well-known notion of
tree decomposition. We then use this hierarchy of graph classes to infer a
complexity hierarchy of homomorphism problems which is comprehensive up to a
computationally very weak notion of reduction, namely, a parameterized version
of quantifier-free first-order reduction. In doing so, we obtain a
significantly refined complexity classification of homomorphism problems, as
well as a unifying, modular, and conceptually clean treatment of existing
complexity classifications. We then present and develop the theory of
Ehrenfeucht-Fraisse-style pebble games which solve the homomorphism problems
where the cores of the structures in A have bounded tree depth. Finally, we use
our framework to classify the complexity of model checking existential
sentences having bounded quantifier rank.


title:
Modeling and Predicting the Growth and Death of Membership-based
  Websites

abstract:
  Driven by outstanding success stories of Internet startups such as Facebook
and The Huffington Post, recent studies have thoroughly described their growth.
These highly visible online success stories, however, overshadow an untold
number of similar ventures that fail. The study of website popularity is
ultimately incomplete without general mechanisms that can describe both
successes and failures. In this work we present six years of the daily number
of users (DAU) of twenty-two membership-based websites - encompassing online
social networks, grassroots movements, online forums, and membership-only
Internet stores - well balanced between successes and failures. We then propose
a combination of reaction-diffusion-decay processes whose resulting equations
seem not only to describe well the observed DAU time series but also provide
means to roughly predict their evolution. This model allows an approximate
automatic DAU-based classification of websites into self-sustainable v.s.
unsustainable and whether the startup growth is mostly driven by marketing &
media campaigns or word-of-mouth adoptions.


title: The same-sign top signature of R-parity violation

abstract:
  Baryonic R-parity violation could explain why low-scale supersymmetry has not
yet been discovered at colliders: sparticles would be hidden in the intense
hadronic activity. However, if the known flavor structures are any guide, the
largest baryon number violating couplings are those involving the top/stop, so
a copious production of same-sign top-quark pairs is in principle possible.
Such a signal, with its low irreducible background and efficient identification
through same-sign dileptons, provides us with tell-tale signs of baryon number
violating supersymmetry. Interestingly, this statement is mostly independent of
the details of the supersymmetric mass spectrum. So, in this paper, after
analyzing the sparticle decay chains and lifetimes, we formulate a simplified
benchmark strategy that covers most supersymmetric scenarios. We then use this
information to interpret the same-sign dilepton searches of CMS, draw
approximate bounds on the gluino and squark masses, and extrapolate the reach
of the future 14 TeV runs.


title: On equivariant Euler-Poincar\'e characteristic in sheaf cohomology

abstract:
  Let X be a topological Hausdorff space together with a continuous action of a
finite group G. Let R be the ring of integers of a number field F. Let E be a
G-sheaf of flat R-modules over X and let $\Phi$ be a G-stable paracompactifying
family of supports on X. We show that under some natural cohomological
finiteness conditions the Lefschetz number of the action of g in G on the
cohomology $H_\Phi(X,E) \otimes_{R} F$ equals the Lefschetz number of the
g-action on $H_\Phi(X^g, E_{|X^g}) \otimes_{R} F$, where $X^g$ is the set of
fixed points of g in X. More generally, the class $\sum_j (-1)^j [H^j_\Phi
(X,E) \otimes_R F]$ in the character group equals a sum of representations
induced from irreducible F-rational representations $V_\lambda$ of $H$ where
$H$ runs in the set of G-conjugacy classes of subgroups of G. The integral
coefficients $m_\lambda$ in this sum are explicitly determined.


title:
Unveiling the gas and dust disk structure in HD 163296 using ALMA
  observations

abstract:
  Aims: The aim of this work is to study the structure of the protoplanetary
disk surrounding the Herbig Ae star HD 163296. Methods: We have used
high-resolution and high-sensitivity ALMA observations of the CO(3-2) emission
line and the continuum at 850 microns, as well as the 3- dimensional radiative
transfer code MCFOST to model the data presented in this work. Results: The
CO(3-2) emission unveils for the first time at sub-millimeter frequencies the
vertical structure details of a gaseous disk in Keplerian rotation, showing the
back- and the front-side of a flared disk. Continuum emission at 850 microns
reveals a compact dust disk with a 240 AU outer radius and a surface brightness
profile that shows a very steep decline at radius larger than 125 AU. The
gaseous disk is more than two times larger than the dust disk, with a similar
critical radius but with a shallower radial profile. Radiative transfer models
of the continuum data confirms the need for a sharp outer edge to the dust
disk. The models for the CO(3-2) channel map require the disk to be slightly
more geometrically thick than previous models suggested, and that the
temperature at which CO gas becomes depleted (frozen-out) from the outer
regions of the disk midplane is T < 20 K, in agreement with previous studies.


title:
Tunable optical absorption and interactions in graphene via oxygen
  plasma

abstract:
  We report significant changes of optical conductivity in single layer
graphene induced by mild oxygen plasma exposure, and explore the interplay
between carrier doping, disorder, and many-body interactions from their
signatures in the absorption spectrum. The first distinctive effect is the
reduction of the excitonic binding energy that can be extracted from the
renormalized saddle point resonance at 4.64 eV. Secondly, the real part of the
frequency-dependent conductivity is nearly completely suppressed below an
exposure-dependent threshold in the near infrared range. The clear step-like
suppression follows the Pauli blocking behaviour expected for doped monolayer
graphene. The nearly zero residual conductivity at frequencies below 2Ef can be
interpreted as arising from the weakening of the electronic self-energy. Our
data shows that mild oxygen exposure can be used to controlably dope graphene
without introducing the strong physical and chemical changes that are common in
other approaches to oxidized graphene, allowing a controllable manipulation of
the optical properties of graphene.


title: Equilibrium dynamics of the Dean-Kawasaki model: MCT and beyond

abstract:
  We extend a previously proposed field-theoretic self-consistent perturbation
approach for the equilibrium dynamics of the Dean-Kawasaki equation presented
in [J. Stat. Mech. 2008 P02004]. By taking terms missing in the latter analysis
into account we arrive at a set of three new equations for correlation
functions of the system. These correlations involve the density and its
logarithm as local observables. Our new one-loop equations, which must
carefully deal with the noninteracting Brownian gas theory, are more general
than the historic Mode-Coupling one in that a further and well-defined
approximation leads back to the original mode-coupling equation for the density
correlations alone. However, without performing any further approximation step,
our set of three equations does not feature any ergodic-non ergodic transition,
as opposed to the historical mode- coupling approach.


title: On sparsity averaging

abstract:
  Recent developments in Carrillo et al. (2012) and Carrillo et al. (2013)
introduced a novel regularization method for compressive imaging in the context
of compressed sensing with coherent redundant dictionaries. The approach relies
on the observation that natural images exhibit strong average sparsity over
multiple coherent frames. The associated reconstruction algorithm, based on an
analysis prior and a reweighted $\ell_1$ scheme, is dubbed Sparsity Averaging
Reweighted Analysis (SARA). We review these advances and extend associated
simulations establishing the superiority of SARA to regularization methods
based on sparsity in a single frame, for a generic spread spectrum acquisition
and for a Fourier acquisition of particular interest in radio astronomy.


title: Scaled control in the QED regime

abstract:
  We develop many-server asymptotics in the QED regime for models with
admission control. The admission control, designed to reduce the incoming
traffic in periods of congestion, scales with the size of the system. For a
class of Markovian models with this scaled control, we identify the QED limits
for two stationary performance measures. We also derive corrected QED
approximations, generalizing earlier results for the Erlang B, C and A models.
These results are useful for the dimensioning of large systems equipped with an
active control policy. In particular, the corrected approximations can be
leveraged to establish the optimality gaps related to square-root staffing and
asymptotic dimensioning with admission control.


title:
Geometry for separable states and construction of entangled states with
  positive partial transposes

abstract:
  We construct faces of the convex set of all $2\otimes 4$ bipartite separable
states, which are affinely isomorphic to the simplex $\Delta_{9}$ with ten
extreme points. Every interior point of these faces is a separable state which
has a unique decomposition into 10 product states, even though ranks of the
state and its partial transpose are 5 and 7, respectively. We also note that
the number 10 is greater than $2\times 4$, to disprove a conjecture on the
lengths of qubit-qudit separable states. This face is inscribed in the
corresponding face of the convex set of all PPT states so that sub-simplices
$\Delta_k$ of $\Delta_{9}$ share the boundary if and only if $k\le 5$. This
enables us to find a large class of $2\otimes 4$ PPT entangled edge states with
rank five.


title:
Sharp weighted Sobolev and Gagliardo-Nirenberg inequalities on half
  space via mass transport and consequences

abstract:
  By adapting the mass transportation technique of Cordero-Erausquin, Nazaret
and Villani, we obtain a family of sharp Sobolev and Gagliardo-Nirenberg (GN)
inequalities on the half space $\mathbf{R}^{n-1}\times\mathbf{R}_+$, $n\geq 1$
equipped with the weight $\omega(x) = x_n^a$, $a\geq 0$. It amounts to work
with the fractional dimension $n_a = n+a$. The extremal functions in the
weighted Sobolev inequalities are fully characterized. Using a dimension
reduction argument and the weighted Sobolev inequalities, we can reproduce a
subfamily of the sharp GN inequalities on the Euclidean space due to Del Pino
and Dolbeault, and obtain some new sharp GN inequalities as well. Our weighted
inequalities are also extended to the domain $\mathbf{R}^{n-m}\times
\mathbf{R}^m_+$ and the weights are $\omega(x,t) = t_1^{a_1}\dots t_m^{a_m}$,
where $n\geq m$, $m\geq 0$ and $a_1,\cdots,a_m\geq 0$. A weighted
$L^p$-logarithmic Sobolev inequality is derived from these inequalities.


title: A helical jet model for OJ287

abstract:
  Context. OJ287 is a quasar with a quasi-periodic optical light curve, with
the periodicity observed for over 120 years. This has lead to a binary black
hole model as a common explanation of the quasar. The radio jet of OJ287 has
been observed for a shorter time of about 30 years. It has a complicated
structure that varies dramatically in a few years time scale. Aims. Here we
propose that this structure arises from a helical jet being observed from a
small and varying viewing angle. The viewing angle variation is taken to be in
tune with the binary orbital motion. Methods. We calculate the effect of the
secondary black hole on the inner edge of the accretion disk of the primary
using particle simulations. We presume that the axis of the helix is
perpendicular to the disk. We then follow the jet motion on its helical path
and project the jet to the sky plane. This projection is compared with
observations both at mm waves and cm waves. Results. We find that this model
reproduces the observations well if the changes in the axis of the conical
helix propagate outwards with a relativistic speed of about 0.85c. In
particular, this model explains at the same time the long-term optical
brightness variations as varying Doppler beaming in a component close to the
core, i.e. at parsec scale in real linear distance, while the mm and cm radio
jet observations are explained as being due to jet wobble at much larger (100
parsec scale) distances from the core.


title: Maximum of a log-correlated Gaussian field

abstract:
  We study the maximum of a Gaussian field on $[0,1]^\d$ ($\d \geq 1$) whose
correlations decay logarithmically with the distance. Kahane \cite{Kah85}
introduced this model to construct mathematically the Gaussian multiplicative
chaos in the subcritical case. Duplantier, Rhodes, Sheffield and Vargas
\cite{DRSV12a} \cite{DRSV12b} extended Kahane's construction to the critical
case and established the KPZ formula at criticality. Moreover, they made in
\cite{DRSV12a} several conjectures on the supercritical case and on the maximum
of this Gaussian field. In this paper we resolve Conjecture 12 in
\cite{DRSV12a}: we establish the convergence in law of the maximum and show
that the limit law is the Gumbel distribution convoluted by the limit of the
derivative martingale.


title:
Listening to galaxies tuning at z ~ 2.5 - 3.0: The first strikes of the
  Hubble fork

abstract:
  We investigate the morphological properties of 494 galaxies selected from the
GMASS survey at z>1, primarily in their optical rest frame, using HST images,
from the CANDELS survey. We propose that the Hubble sequence of galaxy
morphologies takes shape at redshift 2.5<z<3. The fractions of both ellipticals
and disks decrease with increasing lookback time at z>1, such that at redshifts
z=2.5-2.7 and above, the Hubble types cannot be identified, and most galaxies
are classified as irregular. The quantitative morphological analysis shows
that, at 1<z<3, morphological parameters are not as effective in distinguishing
the different morphological Hubble types as they are at low redshift. No
significant morphological k-correction was found to be required for the Hubble
type classification, with some exceptions. In general, different morphological
types occupy the two peaks of the rest-frame (U-B) colour bimodality of
galaxies: most irregulars occupy the blue peak, while ellipticals are mainly
found in the red peak, though with some level of contamination. Disks are more
evenly distributed than either irregulars and ellipticals. We find that the
position of a galaxy in a UVJ diagram is related to its morphological type: the
"quiescent" region of the plot is mainly occupied by ellipticals and, to a
lesser extent, by disks. We find that only ~33% of all morphological
ellipticals in our sample are red and passively evolving galaxies. Blue
galaxies morphologically classified as ellipticals show a remarkable structural
similarity to red ones. Almost all irregulars have a star-forming galaxy
spectrum. In addition, the majority of disks show some sign of star-formation
activity in their spectra, though in some cases their red continuum is
indicative of old stellar populations. Finally, an elliptical morphology may be
associated with either passively evolving or strongly star-forming galaxies.


title:
Spacetime emergence via holographic RG flow from incompressible
  Navier-Stokes at the horizon

abstract:
  We show that holographic RG flow can be defined precisely such that it
corresponds to emergence of spacetime. We consider the case of pure Einstein's
gravity with a negative cosmological constant in the dual hydrodynamic regime.
The holographic RG flow is a system of first order differential equations for
radial evolution of the energy-momentum tensor and the variables which
parametrize it's phenomenological form on hypersurfaces in a foliation. The RG
flow can be constructed without explicit knowledge of the bulk metric provided
the hypersurface foliation is of a special kind. The bulk metric can be
reconstructed once the RG flow equations are solved. We show that the full
spacetime can be determined from the RG flow by requiring that the horizon
fluid is a fixed point in a certain scaling limit leading to the
non-relativistic incompressible Navier-Stokes dynamics. This restricts the
near-horizon forms of all transport coefficients, which are thus determined
independently of their asymptotic values and the RG flow can be solved
uniquely. We are therefore able to recover the known boundary values of almost
all transport coefficients at the first and second orders in the derivative
expansion. We conjecture that the complete characterisation of the general
holographic RG flow, including the choice of counterterms, might be determined
from the hydrodynamic regime.


title:
Specifying Gaussian Markov Random Fields with Incomplete Orthogonal
  Factorization using Givens Rotations

abstract:
  In this paper an approach for finding a sparse incomplete Cholesky factor
through an incomplete orthogonal factorization with Givens rotations is
discussed and applied to Gaussian Markov random fields (GMRFs). The incomplete
Cholesky factor obtained from the incomplete orthogonal factorization is
usually sparser than the commonly used Cholesky factor obtained through the
standard Cholesky factorization. On the computational side, this approach can
provide a sparser Cholesky factor, which gives a computationally more efficient
representation of GMRFs. On the theoretical side, this approach is stable and
robust and always returns a sparse Cholesky factor. Since this approach applies
both to square matrices and to rectangle matrices, it works well not only on
precision matrices for GMRFs but also when the GMRFs are conditioned on a
subset of the variables or on observed data. Some common structures for
precision matrices are tested in order to illustrate the usefulness of the
approach. One drawback to this approach is that the incomplete orthogonal
factorization is usually slower than the standard Cholesky factorization
implemented in standard libraries and currently it can be slower to build the
sparse Cholesky factor.


title:
Phase Reduction in the Noise Induced Escape Problem for Systems close to
  Reversibility

abstract:
  We consider n-dimensional deterministic flows obtained by perturbing a
gradient flow. We assume that the gradient flow admits a stable curve of
stationary points, and thus if the perturbation is not too large the perturbed
flow also admits an attracting curve. We show that the noise induced escape
problem from a stable fixed point of this curve can be reduced to a
one-dimensional problem: we can approximate the associated quasipotential by
the one associated to the restricted dynamics on the stable curve. The error of
this approximation is given in terms of the size of the perturbation.


title: Matching Known Patients to Health Records in Washington State Data

abstract:
  The State of Washington sells patient-level health data for $50. This
publicly available dataset has virtually all hospitalizations occurring in the
State in a given year, including patient demographics, diagnoses, procedures,
attending physician, hospital, a summary of charges, and how the bill was paid.
It does not contain patient names or addresses (only ZIPs). Newspaper stories
printed in the State for the same year that contain the word "hospitalized"
often include a patient's name and residential information and explain why the
person was hospitalized, such as vehicle accident or assault. News information
uniquely and exactly matched medical records in the State database for 35 of
the 81 cases (or 43 percent) found in 2011, thereby putting names to patient
records. A news reporter verified matches by contacting patients. Employers,
financial organizations and others know the same kind of information as
reported in news stories making it just as easy for them to identify the
medical records of employees, debtors, and others.


title:
On digital simply connected spaces and manifolds: a digital simply
  connected 3-manifold is the digital 3-sphere

abstract:
  In the framework of digital topology, we study structural and topological
properties of digital n-dimensional manifolds. We introduce the notion of
simple connectedness of a digital space and prove that if M and N are homotopy
equivalent digital spaces and M is simply connected, then so is N. We show that
a simply connected digital 2-manifold is the digital 2-sphere and a simply
connected digital 3-manifold is the digital 3-sphere. This property can be
considered as a digital form of the Poincar\'e conjecture for continuous
three-manifolds.


title:
Clustering of Complex Networks and Community Detection Using Group
  Search Optimization

abstract:
  Group Search Optimizer(GSO) is one of the best algorithms, is very new in the
field of Evolutionary Computing. It is very robust and efficient algorithm,
which is inspired by animal searching behaviour. The paper describes an
application of GSO to clustering of networks. We have tested GSO against five
standard benchmark datasets, GSO algorithm is proved very competitive in terms
of accuracy and convergence speed.


title: Supersymmetric SU(5) Grand Unification for a Post Higgs Boson Era

abstract:
  We investigate models of supersymmetric grand unification based on the gauge
group SU(5). We consider models with non-universal gaugino masses and confront
them with low energy constraints, including the Higgs boson mass and the Dark
Matter relic density. We also discuss fine-tuning and show the effect of not
including the mu-parameter into fine tuning determinations. With this
relaxation, we find viable scenarios with low fine tuning and study some model
choices for gaugino mass ratios. We demonstrate that some orbifold inspired
models may provide low fine-tuning and the preferred relic abundance of Dark
Matter while evading all experimental constraints. We present benchmarks that
should be explored at the LHC and future colliders.


title:
First-principles study of Co concentration and interfacial resonance
  states in Fe$_{1-x}$Co$_x$ magnetic tunnel junctions

abstract:
  The optimal Co concentration in Fe$_{1-x}$Co$_{x}$/MgO magnetic tunnel
junctions (MTJs) that maximizes tunneling magnetoresistance (TMR) is still
under investigation. We perform a first-principles transport study on MTJs
using disordered electrodes modeled using the virtual crystal approximation
(VCA) and ordered alloys with various MgO barrier thicknesses. We find that
10-20$%$ Co concentration maximizes TMR using VCA to represent disorder in the
electrodes. This TMR peak arises due to a minority d-type interfacial resonance
state (IRS) that becomes filled with small Co doping, leading to a decrease in
antiparallel conductance. Calculations with ordered Fe$_{1-x}$Co$_{x}$
electrodes confirm the filling of this minority d-type IRS for small Co
concentrations. In addition, we construct a 10x10 supercell without VCA to
explicitly represent disorder at the Fe$_{1-x}$Co$_x$/MgO interface, which
demonstrates a quenching of the minority-d IRS and significant reduction in
available states at the Fermi level that agrees with VCA calculations. These
results explain recent experimental findings and provide implications for the
impact of IRS on conductance and TMR in Fe$_{1-x}$Co$_x$/MgO tunnel junctions.


title:
Proposal for implementing the three-qubit refined Deutsch-Jozsa quantum
  algorithm

abstract:
  We propose a way to implement a three-qubit refined Deutsh-Jozsa (DJ)
algorithm. The present proposal is based on the construction of the 35
$f$-controlled phase gates, which uses single-qubit $\sigma_z$ gates and
two-qubit {\it standard} controlled-phase (CP) gates only. This proposal is
implementable because a single-qubit $\sigma_z$ gate can be easily realized by
applying a single classical pulse and a two-qubit CP gate has been
experimentally demonstrated in various physical systems. Finally, it is noted
that this proposal is quite general, and can be applied to implement a
three-qubit refined DJ algorithm in a cavity-based or noncavity-based physical
system.


title: 2DEGs at perovskite interfaces between KTaO3 or KNbO3 and stannates

abstract:
  We report density functional studies of electron rich interfaces between
KTaO3 or KNbO3 and CaSnO3 or ZnSnO3 and in particular the nature of the
interfacial electron gasses that can be formed. We find that depending on the
details these may occur on either the transition metal or stannate sides of the
interface and in the later case can be shifted away from the interface by
ferroelectricity. We also present calculations for bulk KNbO3, KTaO3, CaSnO3,
BaSnO3 and ZnSnO3, showing the different transport and optical properties that
may be expected on the two sides of such interfaces. The results suggest that
these interfaces may display a wide range of behaviors depending on conditions,
and in particular the interplay with ferroelectricity suggests that electrical
control of these properties may be possible.


title:
Magnetic transition and spin dynamics in the triangular Heisenberg
  antiferromagnet $\alpha$-KCrO$_{2}$

abstract:
  We present the results of muon-spin relaxation measurements on the triangular
lattice Heisenberg antiferromagnet $\alpha$-KCrO$_{2}$. We observe sharp
changes in behaviour at an ordering temperature of $T_{\mathrm{c}}=23$ K, with
an additional broad feature in the muon-spin relaxation rate evident at T=13 K,
both of which correspond to features in the magnetic contribution to the heat
capacity. This behaviour is distinct from both the Li- and Na- containing
members of the series. These data may be qualitatively described with the
established theoretical predictions for the underlying spin system.


title: More On Critical Collapse of Axion-Dilaton System in Dimension Four

abstract:
  We complete our previous study of critical gravitational collapse in the
axion-dilaton system by analysing the hyperbolic and parabolic ans\"atze. As
could be expected, the corresponding Choptuik exponents in four-dimensions
differ from the elliptic case.


title:
Multivariate Gaussian Random Fields Using Systems of Stochastic Partial
  Differential Equations

abstract:
  In this paper a new approach for constructing \emph{multivariate} Gaussian
random fields (GRFs) using systems of stochastic partial differential equations
(SPDEs) has been introduced and applied to simulated data and real data. By
solving a system of SPDEs, we can construct multivariate GRFs. On the
theoretical side, the notorious requirement of non-negative definiteness for
the covariance matrix of the GRF is satisfied since the constructed covariance
matrices with this approach are automatically symmetric positive definite.
Using the approximate stochastic weak solutions to the systems of SPDEs,
multivariate GRFs are represented by multivariate Gaussian \emph{Markov} random
fields (GMRFs) with sparse precision matrices. Therefore, on the computational
side, the sparse structures make it possible to use numerical algorithms for
sparse matrices to do fast sampling from the random fields and statistical
inference. Therefore, the \emph{big-n} problem can also be partially resolved
for these models. These models out-preform existing multivariate GRF models on
a commonly used real dataset.


title:
The Application of a Data Mining Framework to Energy Usage Profiling in
  Domestic Residences using UK data

abstract:
  This paper describes a method for defining representative load profiles for
domestic electricity users in the UK. It considers bottom up and clustering
methods and then details the research plans for implementing and improving
existing framework approaches based on the overall usage profile. The work
focuses on adapting and applying analysis framework approaches to UK energy
data in order to determine the effectiveness of creating a few (single figures)
archetypical users with the intention of improving on the current methods of
determining usage profiles. The work is currently in progress and the paper
details initial results using data collected in Milton Keynes around 1990.
Various possible enhancements to the work are considered including a split
based on temperature to reflect the varying UK weather conditions.


title: Multi-parameter Quantum Groups via Quantum Quasi-Symmetric Algebras

abstract:
  It is proved that the entire multi-parameter (small-)quantum groups of
symmetrizable Kac-Moody algebras can be realized as certain subquotients of the
cotensor Hopf algebras. This is an axiomatic construction. Hopf 2-cocycle
deformations variation for the construction machinery is described, moreover,
the integrable irreducible modules can be constructed using this setting, even
available for those in the fundamental alcove at root of unity case.


title:
Link-weight distribution of microRNA co-target networks exhibit
  universality

abstract:
  MicroRNAs (miRNAs) are small non-coding RNAs which regulate gene expression
by binding to the 3' UTR of the corresponding messenger RNAs. We construct
miRNA co-target networks for 22 different species using a target prediction
database, MicroCosm Tagets. The miRNA pairs of individual species having one or
more common target genes are connected and the number of co-targets are
assigned as the weight of these links. We show that the link-weight
distributions of all the species collapse remarkably onto each other when
scaled suitably. It turns out that the scale-factor is a measure of complexity
of the species. A simple model, where targets are chosen randomly by miRNAs,
could provide the correct scaling function and explain the universality.


title:
A White Noise Approach to the Feynman Integrand for Electrons in Random
  Media

abstract:
  Using the Feynman path integral representation of quantum mechanics it is
possible to derive a model of an electron in a random system containing dense
and weakly-coupled scatterers, see [Proc. Phys. Soc. 83, 495-496 (1964)]. The
main goal of this paper is to give a mathematically rigorous realization of the
corresponding Feynman integrand in dimension one based on the theory of white
noise analysis. We refine and apply a Wick formula for the product of a
square-integrable function with Donsker's delta functions and use a method of
complex scaling. As an essential part of the proof we also establish the
existence of the exponential of the self-intersection local times of a
one-dimensional Brownian bridge. As result we obtain a neat formula for the
propagator with identical start and end point. Thus, we obtain a well-defined
mathematical object which is used to calculate the density of states, see e.g.
[Proc. Phys. Soc. 83, 495-496 (1964)].


title:
Multivariate Gaussian Random Fields with Oscillating Covariance
  Functions using Systems of Stochastic Partial Differential Equations

abstract:
  In this paper we propose a new approach for constructing \emph{multivariate}
Gaussian random fields (GRFs) with oscillating covariance functions through
systems of stochastic partial differential equations (SPDEs). We discuss how to
build systems of SPDEs that introduces oscillation characteristics in the
covariance functions of the multivariate GRFs. By choosing different
parametrization of the equations, some GRFs can be made with oscillating
covariance functions but other fields can have Mat\'ern covariance functions or
close to Mat\'ern covariance functions. The multivariate GRFs constructed by
solving the systems of SPDEs automatically fulfill the hard requirement of
nonnegative definiteness for the covariance functions. The approximate weak
solutions to the systems of SPDEs are used to represent the multivariate GRFs
by multivariate Gaussian \emph{Markov} random fields (GMRFs). Since the
multivariate GMRFs have sparse precision matrices (inverse of the covariance
matrices), numerical algorithms for sparse matrices can be applied to the
precision matrices for sampling and inference. Thus from a computational point
of view, the \emph{big-n} problem can be partially solved with these types of
models. Another advantage of the method is that the oscillation in the
covariance function can be controlled directly by the parameters in the system
of SPDEs. We show how to use this proposed approach with simulated data and
real data examples.


title:
Creating Personalised Energy Plans. From Groups to Individuals using
  Fuzzy C Means Clustering

abstract:
  Changes in the UK electricity market mean that domestic users will be
required to modify their usage behaviour in order that supplies can be
maintained. Clustering allows usage profiles collected at the household level
to be clustered into groups and assigned a stereotypical profile which can be
used to target marketing campaigns. Fuzzy C Means clustering extends this by
allowing each household to be a member of many groups and hence provides the
opportunity to make personalised offers to the household dependent on their
degree of membership of each group. In addition, feedback can be provided on
how user's changing behaviour is moving them towards more "green" or cost
effective stereotypical usage.


title: "Anti-glitches" in the Quark-Nova model for AXPs

abstract:
  In the Quark-Nova model, AXPs are quark stars surrounded by a degenerate
iron-rich Keplerian ring (a few stellar radii away). AXP bursts are caused by
accretion of chunks from the inner edge of the ring following magnetic field
penetration. For bright bursts, the inner disk is prone to radiation induced
warping which can tilt it into counter-rotation (i.e. retrograde). For AXP
1E2259+586, the 2002 burst satisfies the condition for the formation of a
retrograde inner ring. We hypothesize the 2002 burst reversed the inner ring
setting the scene for the 2012 outburst and "anti-glitch" when the retrograde
inner ring was suddenly accreted leading to the basic observed properties of
the 2012 event.


title:
Examining the Classification Accuracy of TSVMs with ?Feature Selection
  in Comparison with the GLAD Algorithm

abstract:
  Gene expression data sets are used to classify and predict patient diagnostic
categories. As we know, it is extremely difficult and expensive to obtain gene
expression labelled examples. Moreover, conventional supervised approaches
cannot function properly when labelled data (training examples) are
insufficient using Support Vector Machines (SVM) algorithms. Therefore, in this
paper, we suggest Transductive Support Vector Machines (TSVMs) as
semi-supervised learning algorithms, learning with both labelled samples data
and unlabelled samples to perform the classification of microarray data. To
prune the superfluous genes and samples we used a feature selection method
called Recursive Feature Elimination (RFE), which is supposed to enhance the
output of classification and avoid the local optimization problem. We examined
the classification prediction accuracy of the TSVM-RFE algorithm in comparison
with the Genetic Learning Across Datasets (GLAD) algorithm, as both are
semi-supervised learning methods. Comparing these two methods, we found that
the TSVM-RFE surpassed both a SVM using RFE and GLAD.


title:
Introducing Memory and Association Mechanism into a Biologically
  Inspired Visual Model

abstract:
  A famous biologically inspired hierarchical model firstly proposed by
Riesenhuber and Poggio has been successfully applied to multiple visual
recognition tasks. The model is able to achieve a set of position- and
scale-tolerant recognition, which is a central problem in pattern recognition.
In this paper, based on some other biological experimental results, we
introduce the Memory and Association Mechanisms into the above biologically
inspired model. The main motivations of the work are (a) to mimic the active
memory and association mechanism and add the 'top down' adjustment to the above
biologically inspired hierarchical model and (b) to build up an algorithm which
can save the space and keep a good recognition performance. The new model is
also applied to object recognition processes. The primary experimental results
show that our method is efficient with much less memory requirement.


title:
On the extremal values of the number of vertices with an interval
  spectrum on the set of proper edge colorings of the graph of the
  $n$-dimensional cube

abstract:
  For an undirected, simple, finite, connected graph $G$, we denote by $V(G)$
and $E(G)$ the sets of its vertices and edges, respectively. A function
$\varphi:E(G)\rightarrow \{1,...,t\}$ is called a proper edge $t$-coloring of a
graph $G$, if adjacent edges are colored differently and each of $t$ colors is
used. The least value of $t$ for which there exists a proper edge $t$-coloring
of a graph $G$ is denoted by $\chi'(G)$. For any graph $G$, and for any integer
$t$ satisfying the inequality $\chi'(G)\leq t\leq |E(G)|$, we denote by
$\alpha(G,t)$ the set of all proper edge $t$-colorings of $G$. Let us also
define a set $\alpha(G)$ of all proper edge colorings of a graph $G$: $$
\alpha(G)\equiv\bigcup_{t=\chi'(G)}^{|E(G)|}\alpha(G,t). $$
  An arbitrary nonempty finite subset of consecutive integers is called an
interval. If $\varphi\in\alpha(G)$ and $x\in V(G)$, then the set of colors of
edges of $G$ which are incident with $x$ is denoted by $S_G(x,\varphi)$ and is
called a spectrum of the vertex $x$ of the graph $G$ at the proper edge
coloring $\varphi$. If $G$ is a graph and $\varphi\in\alpha(G)$, then define
$f_G(\varphi)\equiv|\{x\in V(G)/S_G(x,\varphi) \textrm{is an interval}\}|$.
  For a graph $G$ and any integer $t$, satisfying the inequality $\chi'(G)\leq
t\leq |E(G)|$, we define: $$
\mu_1(G,t)\equiv\min_{\varphi\in\alpha(G,t)}f_G(\varphi),\qquad
\mu_2(G,t)\equiv\max_{\varphi\in\alpha(G,t)}f_G(\varphi). $$
  For any graph $G$, we set: $$ \mu_{11}(G)\equiv\min_{\chi'(G)\leq
t\leq|E(G)|}\mu_1(G,t),\qquad \mu_{12}(G)\equiv\max_{\chi'(G)\leq
t\leq|E(G)|}\mu_1(G,t), $$ $$ \mu_{21}(G)\equiv\min_{\chi'(G)\leq
t\leq|E(G)|}\mu_2(G,t),\qquad \mu_{22}(G)\equiv\max_{\chi'(G)\leq
t\leq|E(G)|}\mu_2(G,t). $$
  For any positive integer $n$, the exact values of the parameters $\mu_{11}$,
$\mu_{12}$, $\mu_{21}$ and $\mu_{22}$ are found for the graph of the
$n$-dimensional cube.


title: Systems Dynamics or Agent-Based Modelling for Immune Simulation?

abstract:
  In immune system simulation there are two competing simulation approaches:
System Dynamics Simulation (SDS) and Agent-Based Simulation (ABS). In the
literature there is little guidance on how to choose the best approach for a
specific immune problem. Our overall research aim is to develop a framework
that helps researchers with this choice. In this paper we investigate if it is
possible to easily convert simulation models between approaches. With no
explicit guidelines available from the literature we develop and test our own
set of guidelines for converting SDS models into ABS models in a non-spacial
scenario. We also define guidelines to convert ABS into SDS considering a
non-spatial and a spatial scenario. After running some experiments with the
developed models we found that in all cases there are significant differences
between the results produced by the different simulation methods.


title: Quiet in Class: Classification, Noise and the Dendritic Cell Algorithm

abstract:
  Theoretical analyses of the Dendritic Cell Algorithm (DCA) have yielded
several criticisms about its underlying structure and operation. As a result,
several alterations and fixes have been suggested in the literature to correct
for these findings. A contribution of this work is to investigate the effects
of replacing the classification stage of the DCA (which is known to be flawed)
with a traditional machine learning technique. This work goes on to question
the merits of those unique properties of the DCA that are yet to be thoroughly
analysed. If none of these properties can be found to have a benefit over
traditional approaches, then "fixing" the DCA is arguably less efficient than
simply creating a new algorithm. This work examines the dynamic filtering
property of the DCA and questions the utility of this unique feature for the
anomaly detection problem. It is found that this feature, while advantageous
for noisy, time-ordered classification, is not as useful as a traditional
static filter for processing a synthetic dataset. It is concluded that there
are still unique features of the DCA left to investigate. Areas that may be of
benefit to the Artificial Immune Systems community are suggested.


title:
An inequality for the number of vertices with an interval spectrum in
  edge labelings of regular graphs

abstract:
  We consider undirected simple finite graphs. The sets of vertices and edges
of a graph $G$ are denoted by $V(G)$ and $E(G)$, respectively. For a graph $G$,
we denote by $\delta(G)$ and $\eta(G)$ the least degree of a vertex of $G$ and
the number of connected components of $G$, respectively. For a graph $G$ and an
arbitrary subset $V_0\subseteq V(G)$ $G[V_0]$ denotes the subgraph of the graph
$G$ induced by the subset $V_0$ of its vertices. An arbitrary nonempty finite
subset of consecutive integers is called an interval. A function
$\varphi:E(G)\rightarrow \{1,2,\dots,|E(G)|\}$ is called an edge labeling of
the graph $G$, if for arbitrary different edges $e'\in E(G)$ and $e''\in E(G)$,
the inequality $\varphi(e')\neq \varphi(e'')$ holds. If $G$ is a graph, $x$ is
its arbitrary vertex, and $\varphi$ is its arbitrary edge labeling, then the
set $S_G(x,\varphi)\equiv\{\varphi(e)/ e\in E(G), e \textrm{is incident with}
x$\} is called a spectrum of the vertex $x$ of the graph $G$ at its edge
labeling $\varphi$. If $G$ is a graph and $\varphi$ is its arbitrary edge
labeling, then $V_{int}(G,\varphi)\equiv\{x\in V(G)/\;S_G(x,\varphi)\textrm{is
an interval}\}$. For an arbitrary $r$-regular graph $G$ with $r\geq2$ and its
arbitrary edge labeling $\varphi$, the inequality $$
|V_{int}(G,\varphi)|\leq\bigg\lfloor\frac{3\cdot|V(G)|-2\cdot\eta(G[V_{int}(G,\varphi)])}{4}\bigg\rfloor.
$$ is proved.


title:
Cubic moments of Fourier coefficients and pairs of diagonal quartic
  forms

abstract:
  We establish the non-singular Hasse Principle for pairs of diagonal quartic
equations in 22 or more variables. Our methods involve the estimation of a
certain entangled two-dimensional 21st moment of quartic smooth Weyl sums via a
novel cubic moment of Fourier coefficients.


title: Detect adverse drug reactions for drug Alendronate

abstract:
  Adverse drug reaction (ADR) is widely concerned for public health issue. In
this study we propose an original approach to detect the ADRs using feature
matrix and feature selection. The experiments are carried out on the drug
Simvastatin. Major side effects for the drug are detected and better
performance is achieved compared to other computerized methods. The detected
ADRs are based on the computerized method, further investigation is needed.


title: Some limiting laws associated with the integrated Brownian motion

abstract:
  We study some limit theorems for the normalized law of integrated Brownian
motion perturbed by several examples of functionals: the first passage time,
the nth passage time, the last passage time up to a finite horizon and the
supremum. We show that the penalization principle holds in all these cases and
give descriptions of the conditioned processes. In particular, it is remarkable
that the penalization by the nth passage time is independent of n, and always
gives the same conditioned process, i.e. integrated Brownian motion conditioned
not to hit 0. Our results rely on some explicit formulae obtained by Lachal and
on enlargement of filtrations.


title: Artin's Conjecture and systems of diagonal equations

abstract:
  We show that Artin's conjecture concerning p-adic solubility of Diophantine
equations fails for infinitely many systems of r homogeneous diagonal equations
whenever r>1.


title: Secure Source Coding with a Public Helper

abstract:
  We consider secure multi-terminal source coding problems in the presence of a
public helper. Two main scenarios are studied: 1) source coding with a helper
where the coded side information from the helper is eavesdropped by an external
eavesdropper; 2) triangular source coding with a helper where the helper is
considered as a public terminal. We are interested in how the helper can
support the source transmission subject to a constraint on the amount of
information leaked due to its public nature. We characterize the tradeoff
between transmission rate, incurred distortion, and information leakage rate at
the helper/eavesdropper in the form of a rate-distortion-leakage region for
various classes of problems.


title:
Slow scintillation time constants in NaI(Tl) for different interacting
  particles

abstract:
  Very large thallium doped sodium iodide crystals operated underground and in
very low background environment in the context of a dark matter search
experiment have been used to determine scintillation components in the tens of
ms range in the light pulse induced by different interacting particles:
gammas/muons and alphas.


title:
Structural Evolution of 1D Spectral Function from Low- to High-Energy
  Limits

abstract:
  By exactly analyzing the spin-1/2 Luttinger liquid (LL) and numerically
solving a model of a mobile impurity electron in the LL, we obtain the
one-electron spectral function $A(p,\omega)$ in a one-dimensional (1D) metal in
an entire range of $p$ at zero temperature. For $|p|$ near the Fermi point
$p_{\rm F}$, $A(p,\omega)$ is featured by two prominent peaks of spinon and
(anti)holon representing spin-charge separation, but we also find an additional
cusp structure between them. For $|p| \gg p_{\rm F}$, this structure evolves as
a main peak in $A(p,\omega)$ by swallowing the antiholon mode and its
dispersion relation approaches the one of a free electron, implying the
existence of an electron excitation in the whole region, but not quite a
quasiparticle in the Fermi liquid due to ever existing power-law decay of the
excitation.


title:
Search for Single and Pair-Production of Dijet Resonances with the CMS
  Detector

abstract:
  Searches for new physics in the single and paired dijet mass spectrum are
performed using data collected by the CMS experiment at the LHC at a collision
energy of sqrt{s}=7 or sqrt{s}=8 TeV. No evidence for new physics is found and
upper limits are set for various models. At 95% confidence level, a string
resonance in the single dijet spectrum is excluded for masses between 1 and 4.7
TeV and, for the first time, a coloron in the paired dijet spectrum is excluded
for masses between 250 and 740 GeV.


title: A note on a diffeomorphism between two Banach spaces

abstract:
  We provide sufficient conditions for a mapping acting between two Banach
spaces to be a diffeomorphism.


title:
Spatial Modelling of Temperature and Humidity using Systems of
  Stochastic Partial Differential Equations

abstract:
  This work is motivated by constructing a weather simulator for precipitation.
Temperature and humidity are two of the most important driving forces of
precipitation, and the strategy is to have a stochastic model for temperature
and humidity, and use a deterministic model to go from these variables to
precipitation. Temperature and humidity are empirically positively correlated.
Generally speaking, if variables are empirically dependent, then multivariate
models should be considered. In this work we model humidity and temperature in
southern Norway. We want to construct bivariate Gaussian random fields (GRFs)
based on this dataset. The aim of our work is to use the bivariate GRFs to
capture both the dependence structure between humidity and temperature as well
as their spatial dependencies. One important feature for the dataset is that
the humidity and temperature are not necessarily observed at the same
locations. Both univariate and bivariate spatial models are fitted and
compared. For modeling and inference the SPDE approach for univariate models
and the systems of SPDEs approach for multivariate models have been used.
  To evaluate the performance of the difference between the univariate and
bivariate models, we compare predictive performance using some commonly used
scoring rules: mean absolute error, mean-square error and continuous ranked
probability score. The results illustrate that we can capture strong positive
correlation between the temperature and the humidity. Furthermore, the results
also agree with the physical or empirical knowledge. At the end, we conclude
that using the bivariate GRFs to model this dataset is superior to the approach
with independent univariate GRFs both when evaluating point predictions and for
quantifying prediction uncertainty.


title:
On the well posed solutions for nonlinear second order neutral
  difference equations

abstract:
  In this work we investigate the existence of solutions, their uniqueness and
finally dependence on parameters for solutions of second order neutral
nonlinear difference equations. The main tool which we apply is Darbo fixed
point theorem.


title: Atmospheric Retrieval Analysis of the Directly Imaged Exoplanet HR 8799b

abstract:
  Directly-imaged exoplanets are unexplored laboratories for the application of
the spectral and temperature retrieval method, where the chemistry and
composition of their atmospheres are inferred from inverse modeling of the
available data. As a pilot study, we focus on the extrasolar gas giant HR 8799b
for which more than 50 data points are available. We upgrade our non-linear
optimal estimation retrieval method to include a phenomenological model of
clouds that requires the cloud optical depth and monodisperse particle size to
be specified. Previous studies have focused on forward models with assumed
values of the exoplanetary properties; there is no consensus on the best-fit
values of the radius, mass, surface gravity and effective temperature of HR
8799b. We show that cloudfree models produce reasonable fits to the data if the
atmosphere is of super-solar metallicity and non-solar elemental abundances.
Intermediately cloudy models with moderate values of the cloud optical depth
and micron-sized particles provide an equally reasonable fit to the data and
require a lower mean molecular weight. We report our best-fit values for the
radius, mass, surface gravity and effective temperature of HR 8799b. The mean
molecular weight is about 3.8, while the carbon-to-oxygen ratio is about unity
due to the prevalence of carbon monoxide. Our study emphasizes the need for
robust claims about the nature of an exoplanetary atmosphere to be based on
analyses involving both photometry and spectroscopy and inferred from beyond a
few photometric data points, such as are typically reported for hot Jupiters.


title: Signatures of chaos in the dynamics of quantum discord

abstract:
  We identify signatures of chaos in the dynamics of discord in a multiqubit
system collectively modelled as a quantum kicked top. The evolution of discord
between any two qubits is quasiperiodic in regular regions, while in chaotic
regions, the quasiperiodicity is lost. As the initial wave function is varied
from the regular regions to the chaotic sea, a contour plot of the time
averaged discord remarkably reproduces the structures of the classical
stroboscopic map. We also find surprisingly opposite behaviour of two-qubit
discord versus two-qubit entanglement. Our calculations provide the first
evidence of signatures of chaos in dynamically generated discord.


title: On string matching with k mismatches

abstract:
  In this paper we consider several variants of the pattern matching problem.
In particular, we investigate the following problems: 1) Pattern matching with
k mismatches; 2) Approximate counting of mismatches; and 3) Pattern matching
with mismatches. The distance metric used is the Hamming distance. We present
some novel algorithms and techniques for solving these problems. Both
deterministic and randomized algorithms are offered. Variants of these problems
where there could be wild cards in either the text or the pattern or both are
considered. An experimental evaluation of these algorithms is also presented.
The source code is available at http://www.engr.uconn.edu/~man09004/kmis.zip.


title: Superfluid Stiffness of a Driven Dissipative Condensate with Disorder

abstract:
  Observations of macroscopic quantum coherence in driven systems, e.g.
polariton condensates, have strongly stimulated experimental as well as
theoretical efforts during the last decade. We address the question of whether
a driven quantum condensate is a superfluid, allowing for the effects of
disorder and its non-equilibrium nature. We predict that for spatial dimensions
d<4 the superfluid stiffness vanishes once the condensate exceeds a critical
size, and treat in detail the case d=2. Thus a non-equilibrium condensate is
not a superfluid in the thermodynamic limit, even for weak disorder, although
superfluid behavior would persist in small systems.

categories: cond-mat.quant-gas cond-mat.dis-nn cond-mat.mes-hall physics.optics


title:
An investigation into the relationship between type-2 FOU size and
  environmental uncertainty in robotic control

abstract:
  It has been suggested that, when faced with large amounts of uncertainty in
situations of automated control, type-2 fuzzy logic based controllers will
out-perform the simpler type-1 varieties due to the latter lacking the
flexibility to adapt accordingly. This paper aims to investigate this problem
in detail in order to analyse when a type-2 controller will improve upon type-1
performance. A robotic sailing boat is subjected to several experiments in
which the uncertainty and difficulty of the sailing problem is increased in
order to observe the effects on measured performance. Improved performance is
observed but not in every case. The size of the FOU is shown to be have a large
effect on performance with potentially severe performance penalties for
incorrectly sized footprints.


title: Fast radio bursts: the last sign of supramassive neutron stars

abstract:
  Several fast radio bursts have been discovered recently, showing a bright,
highly dispersed millisecond radio pulse. The pulses do not repeat and are not
associated with a known pulsar or gamma-ray burst. The high dispersion suggests
sources at cosmological distances, hence implying an extremely high radio
luminosity, far larger than the power of single pulses from a pulsar. We
suggest that a fast radio burst represents the final signal of a supramassive
rotating neutron star that collapses to a black hole due to magnetic braking.
The neutron star is initially above the critical mass for non-rotating models
and is supported by rapid rotation. As magnetic braking constantly reduces the
spin, the neutron star will suddenly collapse to a black hole several thousand
to million years after its birth. We discuss several formation scenarios for
supramassive neutron stars and estimate the possible observational signatures
{making use of the results of recent numerical general-relativistic
calculations. While the collapse will hide the stellar surface behind an event
horizon, the magnetic-field lines will snap violently. This can turn an almost
ordinary pulsar into a bright radio "blitzar": Accelerated electrons from the
travelling magnetic shock dissipate a significant fraction of the magnetosphere
and produce a massive radio burst that is observable out to z>0.7. Only a few
percent of the neutron stars needs to be supramassive in order to explain the
observed rate. We suggest that fast radio bursts might trace the solitary
formation of stellar mass black holes at high redshifts. These bursts could be
an electromagnetic complement to gravitational-wave emission and reveal a new
formation and evolutionary channel for black holes that are not seen as
gamma-ray bursts. Radio observations of these bursts could trace the
core-collapse supernova rate throughout the universe.


title: A nonlocal two phase Stefan problem

abstract:
  We study a nonlocal version of the two-phase Stefan problem, which models a
phase transition problem between two distinct phases evolving to distinct heat
equations. Mathematically speaking, this consists in deriving a theory for
sign-changing solutions of the equation, ut = J * v - v, v = {\Gamma}(u), where
the monotone graph is given by {\Gamma}(s) = sign(s)(|s|-1)+ . We give general
results of existence, uniqueness and comparison, in the spirit of [2]. Then we
focus on the study of the asymptotic behaviour for sign-changing solutions,
which present challenging difficulties due to the non-monotone evolution of
each phase.


title: Discovering Sequential Patterns in a UK General Practice Database

abstract:
  The wealth of computerised medical information becoming readily available
presents the opportunity to examine patterns of illnesses, therapies and
responses. These patterns may be able to predict illnesses that a patient is
likely to develop, allowing the implementation of preventative actions. In this
paper sequential rule mining is applied to a General Practice database to find
rules involving a patients age, gender and medical history. By incorporating
these rules into current health-care a patient can be highlighted as
susceptible to a future illness based on past or current illnesses, gender and
year of birth. This knowledge has the ability to greatly improve health-care
and reduce health-care costs.


title: Remarks on the Quantum Bohr Compactification

abstract:
  The category of locally compact quantum groups can be described as either
Hopf $*$-homomorphisms between universal quantum groups, or as bicharacters on
reduced quantum groups. We show how So{\l}tan's quantum Bohr compactification
can be used to construct a ``compactification'' in this category. Depending on
the viewpoint, different C$^*$-algebraic compact quantum groups are produced,
but the underlying Hopf $*$-algebras are always, canonically, the same. We show
that a complicated range of behaviours, with C$^*$-completions between the
reduced and universal level, can occur even in the cocommutative case, thus
answering a question of So{\l}tan. We also study such compactifications from
the perspective of (almost) periodic functions. We give a definition of a
periodic element in $L^\infty(\mathbb G)$, involving the antipode, which allows
one to compute the Hopf $*$-algebra of the compactification of $\mathbb G$; we
later study when the antipode assumption can be dropped. In the cocommutative
case we make a detailed study of Runde's notion of a completely almost periodic
functional-- with a slight strengthening, we show that for [SIN] groups this
does recover the Bohr compactification of $\hat G$.


title: On mod $p^c$ transfer and applications

abstract:
  We study a mod $p^c$ analog of the notion of transfer for automorphic forms.
Instead of existence of eigenforms, such transfers yield congruences between
eigenforms but, like transfers, we show that they can be established by a
comparison of trace formulas. This rests on the properties of mod $p^c$ reduced
multiplicities which count congruences between eigenforms. As an application we
construct finite slope $p$-adic {\it continuous} families of Siegel eigenforms
using a comparison of trace formulas.


title: On the average number of subgroups of the group $\Z_m \times \Z_n$

abstract:
  Let $\Z_m$ be the group of residue classes modulo $m$. Let $s(m,n)$ and
$c(m,n)$ denote the total number of subgroups of the group $\Z_m \times \Z_n$
and the number of its cyclic subgroups, respectively, where $m$ and $n$ are
arbitrary positive integers. We derive asymptotic formulas for the sums
$\sum_{m,n\le x} s(m,n)$, $\sum_{m,n\le x} c(m,n)$ and for the corresponding
sums restricted to $\gcd(m,n)>1$, i.e., concerning the groups $\Z_m \times
\Z_n$ having rank two.


title: Normality of spaces of operators and quasi-lattices

abstract:
  We give an overview of normality and conormality properties of pre-ordered
Banach spaces. For pre-ordered Banach spaces $X$ and $Y$ with closed cones we
investigate normality of $B(X,Y)$ in terms of normality and conormality of the
underlying spaces $X$ and $Y$.
  Furthermore, we define a class of ordered Banach spaces called quasi-lattices
which strictly contains the Banach lattices, and we prove that every strictly
convex reflexive ordered Banach space with a closed proper generating cone is a
quasi-lattice. These spaces provide a large class of examples $X$ and $Y$ that
are not Banach lattices, but for which $B(X,Y)$ is normal. In particular, we
show that a Hilbert space $\mathcal{H}$ endowed with a Lorentz cone is a
quasi-lattice (that is not a Banach lattice if $\dim\mathcal{H}\geq3$), and
satisfies an identity analogous to the elementary Banach lattice identity
$\||x|\|=\|x\|$ which holds for all elements $x$ of a Banach lattice. This is
used to show that spaces of operators between such ordered Hilbert spaces are
always absolutely monotone and that the operator norm is positively attained,
as is also always the case for spaces of operators between Banach lattices.


title: Subset method for one-dimensional QCD

abstract:
  We present a subset method which solves the sign problem for QCD at nonzero
quark chemical potential in 0+1 dimensions. The subsets gather gauge
configurations based on the center symmetry of the SU(3) group. We show that
the sign problem is solved for one to five quark flavors and that it slowly
reappears for a larger number of flavors. We formulate an extension of the
center subsets that solves the sign problem for a larger number of flavors as
well. We also derive some new analytical results for this toy model.


title: An Elegant Algorithm for the Construction of Suffix Arrays

abstract:
  The suffix array is a data structure that finds numerous applications in
string processing problems for both linguistic texts and biological data. It
has been introduced as a memory efficient alternative for suffix trees. The
suffix array consists of the sorted suffixes of a string. There are several
linear time suffix array construction algorithms (SACAs) known in the
literature. However, one of the fastest algorithms in practice has a worst case
run time of $O(n^2)$. The problem of designing practically and theoretically
efficient techniques remains open. In this paper we present an elegant
algorithm for suffix array construction which takes linear time with high
probability; the probability is on the space of all possible inputs. Our
algorithm is one of the simplest of the known SACAs and it opens up a new
dimension of suffix array construction that has not been explored until now.
Our algorithm is easily parallelizable. We offer parallel implementations on
various parallel models of computing. We prove a lemma on the $\ell$-mers of a
random string which might find independent applications. We also present
another algorithm that utilizes the above algorithm. This algorithm is called
RadixSA and has a worst case run time of $O(n\log{n})$. RadixSA introduces an
idea that may find independent applications as a speedup technique for other
SACAs. An empirical comparison of RadixSA with other algorithms on various
datasets reveals that our algorithm is one of the fastest algorithms to date.
The C++ source code is freely available at
http://www.engr.uconn.edu/~man09004/radixSA.zip


title: Stabilization of coefficients for partition polynomials

abstract:
  We find that a wide variety of families of partition statistics stabilize in
a fashion similar to $p_k(n)$, the number of partitions of n with k parts,
which satisfies $p_k(n) = p_{k+1}(n + 1), k \geq n/2$. We bound the regions of
stabilization, discuss variants on the phenomenon, and give the limiting
sequence in many cases as the coefficients of a single-variable generating
function. Examples include many statistics that have an Euler product form,
partitions with prescribed subsums, and plane overpartitions.


title:
Cumulative quantum work-deficit versus entanglement in the dynamics of
  an infinite spin chain

abstract:
  We find that the dynamical phase transition (DPT) in nearest-neighbor
bipartite entanglement of time-evolved states of the anisotropic infinite
quantum XY spin chain, in a transverse time-dependent magnetic field, can be
quantitatively characterized by the dynamics of an information-theoretic
quantum correlation measure, namely, quantum work-deficit (QWD). We show that
only those nonequilibrium states exhibit entanglement resurrection after death,
on changing the field parameter during the DPT, for which the cumulative
bipartite QWD is above a threshold. The results point to an interesting
inter-relation between two quantum correlation measures that are conceptualized
from different perspectives.


title:
Approximation methods in Loop Quantum Cosmology: From Gowdy cosmologies
  to inhomogeneous models in Friedmann-Robertson-Walker geometries

abstract:
  We develop approximation methods in the hybrid quantization of the Gowdy
model with linear polarization and a massless scalar field, for the case of
three-torus spatial topology. The loop quantization of the homogeneous
gravitational sector of the Gowdy model (according to the improved dynamics
prescription) and the presence of inhomogeneities lead to a very complicated
Hamiltonian constraint. Therefore, the extraction of physical results calls for
the introduction of well justified approximations. We first show how to
approximate the homogeneous part of the Hamiltonian constraint, corresponding
to Bianchi I geometries, as if it described a Friedmann-Robertson-Walker (FRW)
model corrected with anisotropies. This approximation is valid in the
high-energy sector of the FRW geometry (concerning its contribution to the
constraint) and for anisotropy profiles that are sufficiently smooth. In
addition, for certain families of states associated to regimes of physical
interest, with negligible effects of the anisotropies and small
inhomogeneities, one can approximate the Hamiltonian constraint of the
inhomogeneous system by that of an FRW geometry with a relatively simple matter
content, and then obtain its solutions.


title: Tight-binding couplings in microwave artificial graphene

abstract:
  We experimentally study the propagation of microwaves in an artificial
honeycomb lattice made of dielectric resonators. This evanescent propagation is
well described by a tight-binding model, very much like the propagation of
electrons in graphene. We measure the density of states, as well as the wave
function associated with each eigenfrequency. By changing the distance between
the resonators, it is possible to modulate the amplitude of
next-(next-)nearest-neighbor hopping parameters and to study their effect on
the density of states. The main effect is the density of states becoming
dissymmetric and a shift of the energy of the Dirac points. We study the basic
elements: An isolated resonator, a two-level system, and a square lattice. Our
observations are in good agreement with analytical solutions for corresponding
infinite lattice.


title:
Hartree Approximation to the One Loop Quantum Gravitational Correction
  to the Graviton Mode Function on de Sitter

abstract:
  We use the Hartree approximation to the Einstein equation on de Sitter
background to solve for the one loop correction to the graviton mode function.
This should give a reasonable approximation to how the ensemble of inflationary
gravitons affects a single external graviton. At late times we find that the
one loop correction to the plane wave mode function $u(\eta,k)$ goes like $G
H^2 \ln(a)/a^2$, where $a$ is the inflationary scale factor. One consequence is
that the one loop corrections to the "electric" components of the linearized
Weyl tensor grow compared to the tree order result.


title:
Sharp Constants for Inequalities of Poincar\'e Type: An Application of
  Optimal Control Theory

abstract:
  Sharp constants for an inequality of Poincar\'e type is studied. The problem
is solved by using optimal control theory.


title:
A branch and cut algorithm for minimum spanning trees under conflict
  constraints

abstract:
  We study approaches for the exact solution of the \NP--hard minimum spanning
tree problem under conflict constraints. Given a graph $G(V,E)$ and a set $C
\subset E \times E$ of conflicting edge pairs, the problem consists of finding
a conflict-free minimum spanning tree, i.e. feasible solutions are allowed to
include at most one of the edges from each pair in $C$. The problem was
introduced recently in the literature, with several results on its complexity
and approximability. Some formulations and both exact and heuristic algorithms
were also discussed, but computational results indicate considerably large
duality gaps and a lack of optimality certificates for benchmark instances. In
this paper, we build on the representation of conflict constraints using an
auxiliary conflict graph $\hat{G}(E,C)$, where stable sets correspond to
conflict-free subsets of $E$. We introduce a general preprocessing method and a
branch and cut algorithm using an IP formulation with exponentially sized
classes of valid inequalities for both the spanning tree and the stable set
polytopes. Encouraging computational results indicate that the dual bounds of
our approach are significantly stronger than those previously available,
already in the initial LP relaxation, and we are able to provide new
feasibility and optimality certificates.


title: Bounding Lagrangian widths via geodesic paths

abstract:
  The width of a Lagrangian is the largest capacity of a ball that can be
symplectically embedded into the ambient manifold such that the ball intersects
the Lagrangian exactly along the real part of the ball. Due to Dimitroglou
Rizell, finite width is an obstruction to a Lagrangian admitting an exact
Lagrangian cap in the sense of Eliashberg-Murphy. In this paper we introduce a
new method for bounding the width of a Lagrangian Q by considering the
Lagrangian Floer cohomology of an auxiliary Lagrangian L with respect to a
Hamiltonian whose chords correspond to geodesic paths in Q. This is formalized
as a wrapped version of the Floer-Hofer-Wysocki capacity and we establish an
associated energy-capacity inequality with the help of a closed-open map. For
any orientable Lagrangian Q admitting a metric of non-positive sectional
curvature in a Liouville manifold, we show the width of Q is bounded above by
four times its displacement energy.


title:
Software Tools for the Analysis of the Photocathode Response of
  Photomultiplier Vacuum Tubes

abstract:
  The central institute of electronics (ZEA-2) in the Forschungszentrum Juelich
(FZJ) has developed a system to scan the response of the photocathode of
photomultiplier tubes (PMT). The PMT sits tight on a supporting structure,
while a blue light emitting diode is moved along its surface by two stepper
motors, spanning both the x and y coordinates. All the system is located in a
light-tight box made by wood. A graphical software was developed in-situ to
perform the scan operations under different configurations (e.g., the step size
of the scan and the number of measurements per point). During each point
measurement the current output generated in the vacuum photomultiplier is
processed in sequence by a pre-amplifier (mainly to convert the current signal
into a voltage signal), an amplifier, and by an ADC module (typically a CAEN
N957). The information of the measurement is saved in files at the end of the
scan. Recently, software based on the CERN ROOT and on the Qt libraries was
developed to help the user analyzing deeper the data obtained by the scan. The
new software, cross-platform due to its build performed inside the Qt-IDE, is
described in this note.


title:
Measurements of Higgs boson production and couplings in diboson final
  states with the ATLAS detector at the LHC

abstract:
  Measurements are presented of production properties and couplings of the
recently discovered Higgs boson using the decays into boson pairs,
$H\rightarrow\gamma\gamma$, $H\rightarrow ZZ^{*}\rightarrow 4 \ell$ and
$H\rightarrow W W \rightarrow \ell\nu\ell\nu$. The results are based on the
complete pp collision data sample recorded by the ATLAS experiment at the CERN
Large Hadron Collider at centre-of-mass energies of 7 TeV and 8 TeV,
corresponding to an integrated luminosity of about 25 fb$^{-1}$. Evidence for
Higgs boson production through vector-boson fusion is reported. Results of
combined fits probing Higgs boson couplings to fermions and bosons, as well as
anomalous contributions to loop-induced production and decay modes, are
presented. All measurements are consistent with expectations for the Standard
Model Higgs boson.


title: Lempel-Ziv Parsing in External Memory

abstract:
  For decades, computing the LZ factorization (or LZ77 parsing) of a string has
been a requisite and computationally intensive step in many diverse
applications, including text indexing and data compression. Many algorithms for
LZ77 parsing have been discovered over the years; however, despite the
increasing need to apply LZ77 to massive data sets, no algorithm to date scales
to inputs that exceed the size of internal memory. In this paper we describe
the first algorithm for computing the LZ77 parsing in external memory. Our
algorithm is fast in practice and will allow the next generation of text
indexes to be realised for massive strings and string collections.


title: Higher Dimensional Elko Theory

abstract:
  We show that the so called Elko equation can be derived from a 5-dimensional
Dirac equation. We argue that this result can be relevant for dark matter and
cosmological scenarios. We generalize our procedure to higher dimensions.


title:
Prospects of Hysteresis-Free Abrupt Switching (0mV/dec) in Landau
  Switches

abstract:
  Sub-threshold swing (S) defines the sharpness of ON-OFF switching of a Field
Effect Transistor (FET) with S=0 corresponding to abrupt switching
characteristics. While thermodynamics dictates S to be greater than or equal to
60mV/dec for classical FETs, "Landau switches" use inherently unstable gate
insulators to achieve abrupt switching. Unfortunately, S=0 switching is always
achieved at the expense of an intrinsic hysteresis, making these switches
unsuitable for low-power applications. The fundamental question therefore
remains: Under what condition, hysteresis-free abrupt switching can be achieved
in a Landau switch? In this paper, we first provide an intuitive classification
of all charge based switches in terms of their energy landscapes and identify
two-well energy landscape as the characteristic feature of Landau switches. We
then use nanoelectromechanical field effect transistor (NEMFET) as an
illustrative example of a Landau switch and conclude that a flat energy
landscape is essential for hysteresis-free abrupt switching. In contrast, a
hysteresis-free smooth sub-60mV/dec switching is obtained by stabilizing the
unstable gate insulator in its unstable regime. Our conclusions have broad
implications and may considerably simplify the design of next charge based
logic switch.


title:
Design of Dispersive Delay Structures (DDSs) Formed by Coupled
  C-Sections Using Predistortion with Space Mapping

abstract:
  The concept of space mapping is applied, for the first time, to the design of
microwave dispersive delay structures (DDSs). DDSs are components providing
specified group delay versus frequency responses for real-time radio systems.
The DDSs considered in this paper are formed by cascaded coupled C-sections. It
is first shown that aggressive space mapping does not provide sufficient
accuracy in the synthesis of DDSs. To address this issue, we propose a
predistortion space mapping technique. Compared to aggressive space mapping,
this technique provides enhanced accuracy, while compared to output space
mapping, it provides greater implementation simplicity. Two full-wave and one
experimental examples are provided to illustrate the proposed predistortion
space mapping technique.


title: Evidence for the spin-0 nature of the Higgs boson using ATLAS data

abstract:
  Studies of the spin and parity quantum numbers of the Higgs boson are
presented, based on proton-proton collision data collected by the ATLAS
experiment at the LHC. The Standard Model spin-parity JP = 0+ hypothesis is
compared with alternative hypotheses using the Higgs boson decays H->gamma
gamma, H -> ZZ -> 4 leptons and H->WW -> l nu l nu, as well as the combination
of these channels. The analysed dataset corresponds to an integrated luminosity
of 20.7 fb-1 collected at a centre-of-mass energy of sqrt(s) = 8 TeV. For the H
-> ZZ -> 4-lepton decay mode the dataset corresponding to an integrated
luminosity of 4.6 fb-1 collected at sqrt(s) = 7 TeV is added. The data are
compatible with the Standard Model JP = 0+ quantum numbers for the Higgs boson,
whereas all alternative hypotheses studied in this letter, namely some specific
JP = 0-; 1+; 1-; 2+ models, are excluded at confidence levels above 97.8%. This
exclusion holds independently of the assumptions on the coupling strengths to
the Standard Model particles and in the case of the JP = 2+ model, of the
relative fractions of gluon-fusion and quark-antiquark production of the spin-2
particle. The data thus provide evidence for the spin-0 nature of the Higgs
boson, with positive parity being strongly preferred.


title:
Quantum-classical correspondence in circularly polarized high harmonic
  generation

abstract:
  Using numerical simulations, we show that atomic high order harmonic
generation, HHG, with a circularly polarized laser field offers an ideal
framework for quantum-classical correspondence in strong field physics. With an
appropriate initialization of the system, corresponding to a superposition of
ground and excited state(s), simulated HHG spectra display a narrow strip of
strong harmonic radiation preceded by a gap of missing harmonics in the lower
part of the spectrum. In specific regions of the spectra, HHG tends to lock to
circularly polarized harmonic emission. All these properties are shown to be
closely related to a set of key classical periodic orbits that organize the
recollision dynamics in an intense, circularly polarized field.


title:
Dev-Div- and DevSym-DevCurl-inequalities for incompatible square tensor
  fields with mixed boundary conditions

abstract:
  For an n-dimensional bounded domain we derive some inequalities bounding the
norm of a square tensor field. Concerning the Div-Dev-inequality the bound is
given by the trace-free part and the divergence and the tensor. In the case of
the DevSym-Curl-inequality the bound is given by the trace-free and symmetric
part and the curl of the tensor. For n=3 the bound is given by the trace-free
symmetric part of the tensor and the trace-free part of the curl of the tensor.
Some prototype applications are presented in which the new inequalities may be
used to derive the coercivity of the models.


title: Structural distortion in Ludwigites

abstract:
  Structural distortion in a three-leg-ladder is studied in connection with
Ludwigites, in particular the Fe and Co homometallic ones. Static impurities in
t_{2g}-orbitals as infinite repulsion potentials randomly located in the
three-leg-ladder and a Su-Schrieffer-Heeger like tight-binding Hamiltonian are
proposed and discussed. It is found that such potentials block itinerant
electrons and diminish a structural staggered order parameter, related with
structural distortion, as 3^{-M} being M the number of impurities. This
diminution is in detriment of Peierls like distortion that occurs in these
ladders as in the case of Fe-Ludwigite. On the other hand, this diminution
could explain the lack of structural distortion as in the case of Co-Ludwigite.


title:
Imprint of the symmetry energy on the inner crust and strangeness
  content of neutron stars

abstract:
  In this work we study the effect of the symmetry energy on several properties
of neutron stars. First, we discuss its effect on the density, proton fraction
and pressure of the neutron star crust-core transition. We show that whereas
the first two quantities present a clear correlation with the slope parameter
$L$ of the symmetry energy, no satisfactory correlation is seen between the
transition pressure and $L$. However, a linear combination of the slope and
curvature parameters at $\rho=0.1$ fm$^{-3}$ is well correlated with the
transition pressure. In the second part we analyze the effect of the symmetry
energy on the pasta phase. It is shown that the size of the pasta clusters,
number of nucleons and the cluster proton fraction depend on the density
dependence of the symmetry energy: a small $L$ gives rise to larger clusters.
The influence of the equation of state at subsaturation densities on the
extension of the inner crust of the neutron star is also discussed. Finally,
the effect of the effect of the density dependence of the symmetry energy on
the strangeness content of neutron stars is studied in the last part of the
work. It is found that charged (neutral) hyperons appear at smaller (larger)
densities for smaller values of the slope parameter $L$. A linear correlation
between the radius and the strangeness content of a star with a fixed mass is
also found.


title: Toward Guaranteed Illumination Models for Non-Convex Objects

abstract:
  Illumination variation remains a central challenge in object detection and
recognition. Existing analyses of illumination variation typically pertain to
convex, Lambertian objects, and guarantee quality of approximation in an
average case sense. We show that it is possible to build V(vertex)-description
convex cone models with worst-case performance guarantees, for non-convex
Lambertian objects. Namely, a natural verification test based on the angle to
the constructed cone guarantees to accept any image which is sufficiently
well-approximated by an image of the object under some admissible lighting
condition, and guarantees to reject any image that does not have a sufficiently
good approximation. The cone models are generated by sampling point
illuminations with sufficient density, which follows from a new perturbation
bound for point images in the Lambertian model. As the number of point images
required for guaranteed verification may be large, we introduce a new
formulation for cone preserving dimensionality reduction, which leverages tools
from sparse and low-rank decomposition to reduce the complexity, while
controlling the approximation error with respect to the original cone.


title: Growth of subalgebras and subideals in free Lie algebras

abstract:
  We investigate subalgebras in free Lie algebras, the main tool being relative
growth and cogrowth functions. Our study reveals drastic differences in the
behavior of proper finitely generated subalgebras and nonzero subideals. For
instance, the \textit{growth} of a proper finitely generated subalgebra $H$ of
a free Lie algebra $L$, with respect to any fixed free basis $X$, is
exponentially small compared to the growth of the whole of $L$. Quite opposite,
the \textit{cogrowth} of any nonzero subideal $S$ is exponentially small
compared to the growth of $L$.


title: Relativistic stellar model admitting a quadratic equation of state

abstract:
  A class of solutions describing the interior of a static spherically
symmetric compact anisotropic star is reported. The analytic solution has been
obtained by utilizing the Finch and Skea ({\it Class. Quant. Grav.} {\bf 6}
(1989) 467) ansatz for the metric potential $g_{rr}$ which has a clear
geometric interpretation for the associated background space-time. Based on
physical grounds appropriate bounds on the model parameters have been obtained
and it has been shown that the model admits an equation of state (EOS) which is
quadratic in nature.


title: BGG reciprocity for current algebras

abstract:
  It was conjectured by Bennett, Chari, and Manning that a BGG-type reciprocity
holds for the category of graded representations with finite-dimensional graded
components for the current algebra associated to a simple Lie algebra. We
associate a current algebra to any indecomposable affine Lie algebra and show
that, in this generality, the BGG reciprocity is true for the corresponding
category of representations.


title: Einstein as armchair detective: The case of stimulated radiation

abstract:
  Einstein was in many ways like a detective on a mystery trail, though in his
case he was on the trail of nature's mysteries and not some murder mystery! And
like all good detectives he had a style. It consisted of taking facts that he
knew were correct and forcing nature into a situation that would contradict
this established truth. In this process she would be forced to reveal some new
truths. Einstein's 1917 paper on the quantum theory of radiation is a classic
example of this style and enabled him to predict the existence of stimulated
radiation starting from an analysis of thermodynamic equilibrium between matter
and radiation.


title: Topological Superconductivity and Majorana Fermions in RKKY Systems

abstract:
  We consider quasi one-dimensional RKKY systems in proximity to an s-wave
superconductor. We show that a $2k_F$-peak in the spin susceptibility of the
superconductor in the one-dimensional limit supports helical order of localized
magnetic moments via RKKY interaction, where $k_F$ is the Fermi wavevector. The
magnetic helix is equivalent to a uniform magnetic field and very strong
spin-orbit interaction (SOI) with an effective SOI length $1/2k_F$. We find the
conditions to establish such a magnetic state in atomic chains and
semiconducting nanowires with magnetic atoms or nuclear spins. Generically,
these systems are in a topological phase with Majorana fermions. The inherent
self-tuning of the helix to $2k_F$ eliminates the need to tune the chemical
potential.


title: From dlogs to dilogs; the super Yang-Mills MHV amplitude revisited

abstract:
  Recently, loop integrands for certain Yang-Mills scattering amplitudes and
correlation functions have been shown to be systematically expressible in dlog
form, raising the possibility that these loop integrals can be performed
directly without Feynman parameters. We do so here to give a new description of
the planar 1-loop MHV amplitude in N = 4 super Yang-Mills theory. We explicitly
incorporate the standard Feynman i epsilon prescription into the integrands. We
find that the generic MHV diagram contributing to the 1-loop MHV amplitude,
known as Kermit, is dual conformal invariant up to the choice of reference
twistor explicit in our axial gauge (the generic MHV diagram was already known
to be finite). The new formulae for the amplitude are nontrivially related to
previous ones in the literature. The divergent diagrams are evaluated using
mass regularization. Our techniques extend directly to higher loop diagrams,
and we illustrate this by sketching the evaluation of a non-trivial 2-loop
example. We expect this to lead to a simple and efficient method for computing
amplitudes and correlation functions with less supersymmetry and without the
assumption of planarity.


title: Random Distances Associated with Trapezoids

abstract:
  The distributions of the random distances associated with hexagons, rhombuses
and triangles have been derived and verified in the existing work. All of these
geometric shapes are related to each other and have various applications in
wireless communications, transportation, etc. Hexagons are widely used to model
the cells in cellular networks, while trapezoids can be utilized to model the
edge users in a cellular network with a hexagonal tessellation. In this report,
the distributions of the random distances associated with unit trapezoids are
derived, when two random points are within a unit trapezoid or in two neighbor
unit trapezoids. The mathematical expressions are verified through simulation.
Further, we present the polynomial fit for the PDFs, which can be used to
simplify the computation.


title:
Status of the lower spins in the Rarita-Schwinger four-vector spinor
  $\psi_\mu$ within the method of the combined Lorentz- and Poincar\'e
  invariant projectors

abstract:
  We investigate the status of the lower spin-1/2 companions to spin-3/2 within
the four-vector spinor, $\psi_\mu$. According to its reducibility,
$\psi_\mu\longrightarrow \left[(1/2,1)\oplus (1,1/2)\right]\oplus
[(1/2,0)\oplus (0,1/2)]$ this representation space contains two spin-1/2
sectors, the first one transforming as a genuine Dirac-spinor, $(1/2,0)\oplus
(0,1/2)$, and the second as the companion to spin-3/2 in $(1/2,1)\oplus
(1,1/2)$. In order to correctly identify the covariant spin-1/2 degrees of
freedom in the Rarita-Schwinger field of interest we exploit the properties of
the Casimir invariants of the Lorentz algebra to distinguish between the
irreducible Dirac- and $(1/2,1)\oplus (1,1/2)$ representation spaces and
construct corresponding momentum-independent (static) projectors which we then
combine with a dynamical spin-1/2 Poincar\'e covariant projector. In so doing
we obtain two spin-1/2 wave equation, and prove them to be causal within an
electromagnetic field. We furthermore calculate Compton scattering off each one
of the above states, and find that the amplitudes corresponding to the first
spin-1/2 are identical to those of a Dirac particle and conclude on the
observability of this state. Also for the second spin-1/2 we find finite cross
sections in all directions in the ultra-relativistic limit, and conclude that
its observability is not excluded neither by causality of propagation within an
electromagnetic environment, nor by unitarity of the Compton scattering
amplitudes in the ultraviolet. Finally, we notice that the method of the
combined Lorentz- and Poincar\'e invariant projectors could be instrumental in
opening a new avenue toward the consistent description of any spin by means of
second order Lagrangians written in terms of sufficiently large reducible
representation spaces equipped with separate Lorentz-- and Dirac indices.