title:
Determination of the origin of the spin Seebeck effect - bulk vs.
  interface effects

abstract:
  The observation of the spin Seebeck effect in insulators has meant a
breakthrough for spin caloritronics due to the unique ability to generate pure
spin currents by thermal excitations in insulating systems without moving
charge carriers. Since the recent first observation, the underlying mechanism
and the origin of the observed signals have been discussed highly
controversially. Here we present a characteristic dependence of the
longitudinal spin Seebeck effect amplitude on the thickness of the insulating
ferromagnet (YIG). Our measurements show that the observed behavior cannot be
explained by any effects originating from the interface, such as magnetic
proximity effects in the spin detector (Pt). Comparison to theoretical
calculations of thermal magnonic spin currents yields qualitative agreement for
the thickness dependence resulting from the finite effective magnon propagation
length so that the origin of the effect can be traced to genuine bulk magnonic
spin currents ruling out parasitic interface effects.


title:
Robust multirobot coordination using priority encoded homotopic
  constraints

abstract:
  We study the problem of coordinating multiple robots along fixed geometric
paths. Our contribution is threefold. First we formalize the intuitive concept
of priorities as a binary relation induced by a feasible coordination solution,
without excluding the case of robots following each other on the same geometric
path. Then we prove that two paths in the coordination space are continuously
deformable into each other if and only if they induce the \emph{same priority
graph}, that is, the priority graph uniquely encodes homotopy classes of
coordination solutions. Finally, we give a simple control law allowing to
safely navigate into homotopy classes \emph{under kinodynamic constraints} even
in the presence of unexpected events, such as a sudden robot deceleration
without notice. It appears the freedom within homotopy classes allows to much
deviate from any pre-planned trajectory without ever colliding nor having to
re-plan the assigned priorities.


title:
High Mass Accuracy and High Mass Resolving Power FT-ICR Secondary Ion
  Mass Spectrometry for Biological Tissue Imaging

abstract:
  Biological tissue imaging by secondary ion mass spectrometry has seen rapid
development with the commercial availability of polyatomic primary ion sources.
Endogenous lipids and other small bio-molecules can now be routinely mapped on
the sub-micrometer scale. Such experiments are typically performed on
time-of-flight mass spectrometers for high sensitivity and high repetition rate
imaging. However, such mass analyzers lack the mass resolving power to ensure
separation of isobaric ions and the mass accuracy for elemental formula
assignment based on exact mass measurement. We have recently reported a
secondary ion mass spectrometer with the combination of a C60 primary ion gun
with a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS)
for high mass resolving power, high mass measurement accuracy and tandem mass
spectrometry capabilities. In this work, high specificity and high sensitivity
secondary ion FT-ICR MS was applied to chemical imaging of biological tissue.
An entire rat brain tissue was measured with 150 um spatial resolution (75 um
primary ion spot size) with mass resolving power (m/{\Delta}m50%) of 67,500 (at
m/z 750) and root-mean-square measurement accuracy less than two
parts-per-million for intact phospholipids, small molecules and fragments. For
the first time, ultra-high mass resolving power SIMS has been demonstrated,
with m/{\Delta}m50% > 3,000,000. Higher spatial resolution capabilities of the
platform were tested at a spatial resolution of 20 um. The results represent
order of magnitude improvements in mass resolving power and mass measurement
accuracy for SIMS imaging and the promise of the platform for ultra-high mass
resolving power and high spatial resolution imaging.


title: On the surjectivity of weighted Gaussian maps

abstract:
  We study the surjectivity of suitable weighted Gaussian maps which provide a
natural generalization of the standard Gaussian maps and encode the local
geometry of the locus of curves endowed with a higher root of the canonical
bundle having associated linear system of dimension at least r + 1. In
particular, we get a bound on the dimension of its Zariski tangent space, which
turns out to be sharp in the special case r = 0. Finally, we describe this
locus in the case of complete intersection curves.


title:
Mesoscale Structures at Complex Fluid-Fluid Interfaces: a Novel Lattice
  Boltzmann / Molecular Dynamics Coupling

abstract:
  Complex fluid-fluid interfaces featuring mesoscale structures with adsorbed
particles are key components of newly designed materials which are continuously
enriching the field of soft matter. Simulation tools which are able to cope
with the different scales characterizing these systems are fundamental
requirements for efficient theoretical investigations. In this paper we present
a novel simulation method, based on the approach of Ahlrichs and D\"unweg
[Ahlrichs and D\"unweg, Int. J. Mod. Phys. C, 1998, 9, 1429], that couples the
"Shan-Chen" multicomponent Lattice Boltzmann technique to off-lattice molecular
dynamics to simulate efficiently complex fluid-fluid interfaces.
  We demonstrate how this approach can be used to study a wide class of
challenging problems. Several examples are given, with an accent on
bicontinuous phases formation in polyelectrolyte solutions and ferrofluid
emulsions. We also show that the introduction of solvation free energies in the
particle-fluid interaction unveils the hidden, multiscale nature of the
particle-fluid coupling, allowing to treat symmetrically (and interchangeably)
the on-lattice and off-lattice components of the system.


title: Deformation Constraints on Solitons and D-branes

abstract:
  We derive a set of constraints on soliton solutions using geometric
deformations, and transformations by internal symmetries with space-dependent
parameters. We show that Derrick's theorem and a more complete set of
constraints due to Manton are special cases of these deformation constraints
(DC). We demonstrate also that known soliton solutions obey the DC, and extract
novel results by applying the constraints to systems of D-branes, taking into
account both Dirac-Born-Infeld and Wess-Zumino actions, and examining cases
with and without D-brane gauge fields. We also determine a relation with the
Hamiltonian constraint for gravitational systems, and discuss configurations of
finite extent, like Wilson lines.


title: Measurement of Heavy-Flavor Properties at CMS and ATLAS

abstract:
  Thanks to the excellent performances of ATLAS and CMS in triggering on muon
signals and reconstructing these particles down to low transverse momentum,
large samples of heavy-flavored hadrons have been collected in the 2011 LHC run
at sqrt(s) = 7 TeV. The analysis of these samples has enabled both experiments
to perform competitive measurements of heavy-flavor properties, such as
quarkonium polarization, lifetime and CP-violation measurements, hadron
spectroscopy and branching ratios of rare B decays.


title:
Symmetry properties and spectra of the two-dimensional quantum compass
  model

abstract:
  We use exact symmetry properties of the two-dimensional quantum compass model
to derive nonequivalent invariant subspaces in the energy spectra of $L\times
L$ clusters up to L=6. The symmetry allows one to reduce the original $L\times
L$ compass cluster to the $(L-1)\times (L-1)$ one with modified interactions.
This step is crucial and enables: (i) exact diagonalization of the $6\times 6$
quantum compass cluster, and (ii) finding the specific heat for clusters up to
L=6, with two characteristic energy scales. We investigate the properties of
the ground state and the first excited states and present extrapolation of the
excitation energy with increasing system size. Our analysis provides physical
insights into the nature of nematic order realized in the quantum compass model
at finite temperature. We suggest that the quantum phase transition at the
isotropic interaction point is second order with some admixture of the
discontinuous transition, as indicated by the entropy, the overlap between two
types of nematic order (on horizontal and vertical bonds) and the existence of
the critical exponent. Extrapolation of the specific heat to the $L\to\infty$
limit suggests the classical nature of the quantum compass model and high
degeneracy of the ground state with nematic order.


title: Interpreting signals from astrophysical transient experiments

abstract:
  Time domain astronomy has come of age with astronomers now able to monitor
the sky at high cadence both across the electromagnetic spectrum and using
neutrinos and gravitational waves. The advent of new observing facilities
permits new science, but the ever increasing throughput of facilities demands
efficient communication of coincident detections and better subsequent
coordination among the scientific community so as to turn detections into
scientific discoveries. To discuss the revolution occurring in our ability to
monitor the Universe and the challenges it brings, on 2012 April 25-26 a group
of scientists from observational and theoretical teams studying transients met
with representatives of the major international transient observing facilities
at the Kavli Royal Society International Centre, UK. This immediately followed
the Royal Society Discussion meeting "New windows on transients across the
Universe" held in London. Here we present a summary of the Kavli meeting at
which the participants discussed the science goals common to the transient
astronomy community and analysed how to better meet the challenges ahead as
ever more powerful observational facilities come on stream.


title: Triggered Fronts in the Complex Ginzburg Landau Equation

abstract:
  We study patterns that arise in the wake of an externally triggered,
spatially propagating instability in the complex Ginzburg-Landau equation. We
model the trigger by a spatial inhomogeneity moving with constant speed. In the
comoving frame, the trivial state is unstable to the left of the trigger and
stable to the right. At the trigger location, spatio-temporally periodic
wavetrains nucleate. Our results show existence of coherent, "heteroclinic"
profiles when the speed of the trigger is slightly below the speed of a free
front in the unstable medium. Our results also give expansions for the
wavenumber of wavetrains selected by these coherent fronts. A numerical
comparison yields very good agreement with observations, even for moderate
trigger speeds. Technically, our results provide a heteroclinic bifurcation
study involving an equilibrium with an algebraically double pair of complex
eigenvalues. We use geometric desingularization and invariant foliations to
describe the unfolding. Leading order terms are determined by a condition of
oscillations in a projectivized flow, which can be found by intersecting
absolute spectra with the imaginary axis.


title:
Characterization theorem for Laguerre-Hahn orthogonal polynomials on
  non-uniform lattices

abstract:
  It is stated and proved a characterization theorem for Laguerre-Hahn
orthogonal polynomials on non-uniform lattices. This theorem proves the
equivalence between the Riccati equation for the formal Stieltjes function,
linear first-order difference relations for the orthogonal polynomials as well
as for the associated polynomials of the first kind, and linear first-order
difference relations for the functions of the second kind.


title:
Matrix Online Characteristic Number and Its applications in Goldbach
  Conjecture,Polignac Conjecture,the Twin Prime Conjecture

abstract:
  This article consists of three chapters.In Chapter 1, it is determined by the
consecutive odd numbers, and study to the intrinsic properties of a class of
matrix sequence. Through the establishment of matrix online number concept,
characteristics and the online number column use mathematical induction to
prove the some properties of this kind of matrix on the number of online
features (Theorem 1). Finally, it is given a trial to prove the Goldbach
conjecture (Theorem 6). This is the author in the years to explore prime
properties in the process of research and discovery, and believe that this
finding is of great significance.In Chapter 2, it is defined the concepts of
matrix master characteristic number and the Matrix Master Characteristic
Sequence (Definition 1). Firstly, we prove that any even number can be
expressed as for the difference of two odd prime numbers at least two groups
(Theorem 4). Secondly, we prove that there are infinitely many odd prime
numbers separated by four (Theorem 9). Finally, we prove that if there is
greater than 1 in the intersection by S(3) and s(2m+3) for any natural number
m, so that there are infinitely many odd prime numbers separated by
2m(Theorem11). The results will undoubtedly promote the research for Polignac
conjecture.In Chapter 3, mainly as a result of any odd natural number a, the
intersection by S(a) and s(a+2) is not empty number set, and there are far more
than 1 number in the set, where S(a)={k,If 2k+a be prime as k be natural
number},and P is a prime number set, N is natural number set. we prove that
there are an infinite number of twin prime, and then solve the problem of the
twin primes in number theory.


title: Deposited low temperature silicon GHz modulator

abstract:
  The majority of silicon photonics is built on silicon-on-insulator (SOI)
wafers while the majority of electronics, including CPUs and memory, are built
on bulk silicon wafers, limiting broader acceptance of silicon photonics. This
discrepancy is a result of silicon photonics's requirement for a
single-crystalline silicon (c-Si) layer and a thick undercladding for optical
guiding that bulk silicon wafers to not provide. While the undercladding
problem can be partially addressed by substrate removal techniques, the
complexity of co-integrating photonics with state-of-the-art transistors and
real estate competition between electronics and photonics remain problematic.
We show here a platform for deposited GHz silicon photonics based on
polycrystalline silicon with high optical quality suitable for high performance
electro-optic devices. We demonstrate 3 Gbps polysilicon electro-optic
modulator fabricated on a deposited polysilicon layer fully compatible with
CMOS backend integration. These results open up an array of possibilities for
silicon photonics including photonics on DRAM and flexible substrates.


title: Bounded solutions for a forced bounded oscillator without friction

abstract:
  Under the validity of a Landesman-Lazer type condition, we prove the
existence of solutions bounded on the real line, together with their first
derivatives, for some second order nonlinear differential equation of the form
$\ddot u + g(u) = p(t)$, where the reaction term $g$ is bounded. The proof is
variational, and relies on a dual version of the Nehari method for the
existence of oscillating solutions to superlinear equations.


title:
Fermi gases with imaginary mass imbalance and the sign problem in Monte
  Carlo calculations

abstract:
  Fermi gases in strongly coupled regimes, such as the unitary limit, are
inherently challenging for many-body methods. Although much progress has been
made with purely analytic methods, quantitative results require ab initio
numerical approaches, such as Monte Carlo (MC) calculations. However,
mass-imbalanced and spin-imbalanced gases are not accessible to MC calculations
due to the infamous sign problem. It was recently pointed out that the sign
problem, for finite spin imbalance, can be circumvented by resorting to
imaginary polarizations and analytic continuation. Large parts of the phase
diagram spanned by temperature and polarization then become accessible to MC
calculations. We propose to apply a similar strategy to the mass-imbalanced
case, which opens up the possibility to study the associated phase diagram with
MC calculations. In particular, our analysis suggests that a detection of a
(tri-)critical point in this phase diagram is possible. We also discuss
calculations in the zero-temperature limit with our approach.


title:
Temperature limits in laser cooling of free atoms with three-level
  cascade transitions

abstract:
  We employ semiclassical theoretical analysis to study laser cooling of free
atoms using three-level cascade transitions, where the upper transition is much
weaker than the lower one. This represents an alternate cooling scheme,
particularly useful for group II atoms. We find that temperatures below the
Doppler limits associated with each of these transitions are expected. The
lowest temperatures arise from a remarkable increase in damping and reduced
diffusion compared to two-level cooling. They are reached at the two-photon
resonance, where there is a crossing between the narrow and the partially-dark
dressed states, and can be estimated simply by the usual Doppler limit
considering the decay rate of the optical coherence between these states.


title: On the characterization of Gelfand-Shilov-Roumieu spaces

abstract:
  Generalized $\mathbf{m}$-Gelfand-Shilov-Roumieu vector spaces
$\mathcal{S}_{\mathbf{m}}(\mathbf{X})$ are introduced. Here $\mathbf{m} =
(m^{(1)},...,m^{(n)})$, $\mathbf{X}=(X_{1},...,X_{n})$ and
$m^{(1)},...,m^{(n)}$ are sequences of positive real numbers and
$X_{1},...,X_{n}$ are operators in a Hilbert space. Conditions are given on the
sequences $m^{(1)},...,m^{(n)}$ and on the operators $X_{1},...,X_{n}$ so that
the equality $S_{\mathbf{m}}(\mathbf{X}) = S_{m^{(1)}}(X_{1})\cap ...
\cap{S}_{m^{(n)}}(X_{n})$ is valid. As a corollary we obtain a new proof of a
characterization theorem for classical Gelfand-Shilov spaces.


title: Generalized splines on arbitrary graphs

abstract:
  Let G be a graph whose edges are labeled by ideals of a commutative ring. We
introduce a generalized spline, which is a vertex-labeling of G by elements of
the ring so that the difference between the labels of any two adjacent vertices
lies in the corresponding edge ideal. Generalized splines arise naturally in
combinatorics (em algebraic splines of Billera and others) and in algebraic
topology (certain equivariant cohomology rings, described by
Goresky-Kottwitz-MacPherson and others). The central question of this
manuscript asks when an arbitrary edge-labeled graph has nontrivial generalized
splines. The answer is `always', and we prove the stronger result that
generalized splines contain a free submodule whose rank is the number of
vertices in G. We describe all generalized splines when G is a tree, and give
several ways to describe the ring of generalized splines as an intersection of
generalized splines for simpler subgraphs of G. We also present a new tool
which we call the GKM matrix, an analogue of the incidence matrix of a graph,
and end with open questions.


title: Statistical Review of UK Residential Sector Electrical Loads

abstract:
  This paper presents a comprehensive statistical review of data obtained from
a wide range of literature on the most widely used electrical appliances in the
UK residential load sector. It focuses on individual appliances and begins by
consideration of the electrical operations performed by the load. This approach
allows for the loads to be categorised based on the electrical characteristics,
and also provides information on the reactive power characteristics of the
load, which is often neglected from standard consumption statistics. This data
is particularly important for power system analysis. In addition to this,
device ownership statistics and probability distribution functions of power
demand are presented for the main residential loads. Although the data
presented is primarily intended as a resource for the development of load
profiles for power system analysis, it contains a large volume of information
which provides a useful database for the wider research community.


title:
Differential-algebraic approach to constructing representations of
  commuting differentiations in functional spaces and its application to
  nonlinear integrable dynamical systems

abstract:
  There is developed a differential-algebraic approach to studying the
representations of commuting differentiations in functional differential rings
under nonlinear differential constraints. An example of the differential ideal
with the only one conserved quantity is analyzed in detail, the corresponding
Lax type representations of differentiations are constructed for an infinite
hierarchy of nonlinear dynamical systems of the Burgers and Korteweg-de Vries
type. A related infinite bi-Hamiltonian hierarchy of Lax type dynamical systems
is constructed.


title:
Proposal for a scheme to generate 10 TW-level femtosecond x-ray pulses
  for imaging single protein molecules at the European XFEL

abstract:
  Single biomolecular imaging using XFEL radiation is an emerging method for
protein structure determination using the "diffraction before destruction"
method at near atomic resolution. Crucial parameters for such bio-imaging
experiments are photon energy range, peak power, pulse duration, and transverse
coherence. The largest diffraction signals are achieved at the longest
wavelength that supports a given resolution, which should be better than 0.3
nm. We propose a configuration which combines self-seeding and undulator
tapering techniques with the emittance-spoiler method in order to increase the
XFEL output peak power and to shorten the pulse duration up to a level
sufficient for performing bio-imaging of single protein molecules at the
optimal photon energy range, i.e. around 4 keV. Experiments at the LCLS
confirmed the feasibility of these three new techniques. Based on start-to-end
simulations we demonstrate that self-seeding, combined with undulator tapering,
allows one to achieve up to a 100-fold increase in peak-power. A slotted foil
in the last bunch compressor is added for x-ray pulse duration control.
Simulations indicate that one can achieve diffraction to the desired resolution
with 50 mJ (corresponding to 1e14 photons) per 10 fs pulse at 3.5 keV photon
energy in a 100 nm focus. This result is exemplified using the photosystem I
membrane protein as a case study.


title: Radion cosmology and stabilization

abstract:
  We solve the Einstein's equation in five-dimensional spacetime for Randall
Sundrum Brane world model with time dependent radion field to study variation
of brane scale factor with time. We have shown that as radion field decreases
with time compactifying the extra dimension, the scale factor increases
exponentially with time leading to inflationary scenario. We have also proposed
a time dependent generalization of Goldberger-Wise moduli stabilization
mechanism to explain the time evolution of the radion field to reach a stable
value after which the scale factor on the brane exits from inflationary
expansion.


title: A certified reduction strategy for homological image processing

abstract:
  The analysis of digital images using homological procedures is an outstanding
topic in the area of Computational Algebraic Topology. In this paper, we
describe a certified reduction strategy to deal with digital images, but
preserving their homological properties. We stress both the advantages of our
approach (mainly, the formalisation of the mathematics allowing us to verify
the correctness of algorithms) and some limitations (related to the performance
of the running systems inside proof assistants). The drawbacks are overcome
using techniques that provide an integration of computation and deduction. Our
driving application is a problem in bioinformatics, where the accuracy and
reliability of computations are specially requested.


title: Streamlines of perfect fluid as geodesics in Riemannian space-time

abstract:
  Streamlines of a relativistic perfect isentropic fluid are geodesics of a
Riemannian space whose metric is defined by enthalpy of the fluid. This fact
simplifies the solution of some problems, as is also of interest from the point
of view of fundamental physics.


title: The Role of Trends in Evolving Networks

abstract:
  Modeling complex networks has been the focus of much research for over a
decade. Preferential attachment (PA) is considered a common explanation to the
self organization of evolving networks, suggesting that new nodes prefer to
attach to more popular nodes. The PA model results in broad degree
distributions, found in many networks, but cannot explain other common
properties such as: The growth of nodes arriving late and Clustering (community
structure). Here we show that when the tendency of networks to adhere to trends
is incorporated into the PA model, it can produce networks with such
properties. Namely, in trending networks, newly arriving nodes may become
central at random, forming new clusters. In particular, we show that when the
network is young it is more susceptible to trends, but even older networks may
have trendy new nodes that become central in their structure. Alternatively,
networks can be seen as composed of two parts: static, governed by a power law
degree distribution, and a dynamic part governed by trends, as we show on Wiki
pages. Our results also show that the arrival of trending new nodes not only
creates new clusters, but also has an effect on the relative importance and
centrality of all other nodes in the network. This can explain a variety of
real world networks in economics, social and online networks, and cultural
networks. Products popularity, formed by the network of people's opinions,
exhibit these properties. Some lines of products are increasingly susceptible
to trends and hence to shifts in popularity, while others are less trendy and
hence more stable. We believe that our findings have a big impact on our
understanding of real networks.


title:
Emerging Two-dimensional Materials: graphene and its other structural
  analogues

abstract:
  The study of graphene, since its discovery around 2004, is possibly the
largest and fastest growing field of research in material science, because of
its exotic mechanical, thermal, electronic, optical and chemical properties.
The studies of graphene have also led to further research in exploring the
field of two dimensional (2D) systems in general. For instance, a number of
other 2D crystals (not based on carbon, e.g., boronitrene, silicone, graphane,
etc.) have been synthesized or predicted theoretically in recent years.
Further, theoretical studies have predicted the possibility of other 2D
hexagonal crystals of Ge, SiC, GeC, AlN, GaN, etc. The properties of these 2D
materials are very different from their bulk. We shall present the general
exotic properties of graphene like 2D systems followed by our computational
results on the structural and electronic properties of some of them.


title: RuleRunner technical report

abstract:
  Rule-based run-time monitoring system for finite traces, with FLTL verdict
and quadratic complexity.


title: A Gang of Bandits

abstract:
  Multi-armed bandit problems are receiving a great deal of attention because
they adequately formalize the exploration-exploitation trade-offs arising in
several industrially relevant applications, such as online advertisement and,
more generally, recommendation systems. In many cases, however, these
applications have a strong social component, whose integration in the bandit
algorithm could lead to a dramatic performance increase. For instance, we may
want to serve content to a group of users by taking advantage of an underlying
network of social relationships among them. In this paper, we introduce novel
algorithmic approaches to the solution of such networked bandit problems. More
specifically, we design and analyze a global strategy which allocates a bandit
algorithm to each network node (user) and allows it to "share" signals
(contexts and payoffs) with the neghboring nodes. We then derive two more
scalable variants of this strategy based on different ways of clustering the
graph nodes. We experimentally compare the algorithm and its variants to
state-of-the-art methods for contextual bandits that do not use the relational
information. Our experiments, carried out on synthetic and real-world datasets,
show a marked increase in prediction performance obtained by exploiting the
network structure.


title: Second quantization and gauge invariance

abstract:
  It is well known that the single particle Dirac equation is gauge invariant.
This means that observable quantities, such as the current density, are not
affected by a gauge transformation. However what happens when the method of
second quantization is applied to convert a single particle theory into a field
theory? In this case it will be shown that the theory is no longer gauge
invariant. This will be shown by considering the second quantization of a zero
mass Dirac field in 1+1 dimensions and examining the change of the current
density operator due to a gauge transformation.


title: Social Media and Information Overload: Survey Results

abstract:
  A UK-based online questionnaire investigating aspects of usage of
user-generated media (UGM), such as Facebook, LinkedIn and Twitter, attracted
587 participants. Results show a high degree of engagement with social
networking media such as Facebook, and a significant engagement with other
media such as professional media, microblogs and blogs. Participants who
experience information overload are those who engage less frequently with the
media, rather than those who have fewer posts to read. Professional users show
different behaviours to social users. Microbloggers complain of information
overload to the greatest extent. Two thirds of Twitter-users have felt that
they receive too many posts, and over half of Twitter-users have felt the need
for a tool to filter out the irrelevant posts. Generally speaking, participants
express satisfaction with the media, though a significant minority express a
range of concerns including information overload and privacy.


title: Satisfiability of CTL* with constraints

abstract:
  We show that satisfiability for CTL* with equality-, order-, and
modulo-constraints over Z is decidable. Previously, decidability was only known
for certain fragments of CTL*, e.g., the existential and positive fragments and
EF.


title:
The 5D to 4D projection model applied as a Lepton to Galaxy Creation
  model

abstract:
  The 5D to 4D projection is presented in a simple geometry giving the Perelman
Theorem, resulting in a 3D doughnut structure for the space manifold of the
Lorentz space-time. It is shown that in the lowest quantum state, this Lorentz
manifold confines and gives the de Broglie leptons from the massless 5D
e-trinos. On the scale of the universe, it allows for a model for the creation
of galaxies.


title:
A Critical Assessment of Cost-Based Nash Methods for Demand Scheduling
  in Smart Grids

abstract:
  Demand-side management (DSM) is becoming an increasingly important component
of the envisioned smart grid. The ability to improve the efficiency of energy
use in the power system by altering demand is widely viewed as being not merely
promising but in fact essential. However, while the advantages of DSM are
clear, arriving at an efficient implementation has so far proven to be less
straightforward. There have recently been many proposals put forth in the
literature to tackle the demand scheduling aspect of DSM. One particular
approach based on a game-theoretic treatment of the day-ahead load-scheduling
problem has recently gained tremendous popularity in the DSM literature. In
this letter, an assessment of this approach is conducted, and its main result
is challenged.


title: Dynamic spatial and network sampling

abstract:
  This paper considers some designs for sampling and interventions in dynamic
networks and spatial temporal settings. The sample spreads through the
population largely by tracing network links, although random sampling or
spatial designs may be used in addition. To investigate the effectiveness of
different designs for finding units on which to make observations and introduce
interventions is investigated through simulations. For this purpose a dynamic
spatial network model is developed based on simple stochastic processes. The
sampling processes considered have both acquisition processes and attrition
process by which units are added and removed from the sample. The effect of an
intervention introduced with a given sampling design is assessed by the change
in the resulting equilibrium distribution or, in more detail, by the
distribution of sample paths resulting from the intervention strategy.


title: A goodness-of-fit test for regular vine copula models

abstract:
  We introduce a new goodness-of-fit test for regular vine (R-vine) copula
models. R-vine copulas are a very flexible class of multivariate copulas based
on a pair-copula construction (PCC). The test arises from the information
matrix equality and specification test proposed by White (1982) and extends the
goodness-of-fit test for copulas introduced by Huang and Prokhorov (2011). The
corresponding critical value can be approximated by asymptotic theory or
simulation. The simulation based test shows excellent performance with regard
to observed size and power in an extensive simulation study, while the
asymptotic theory based test is inaccurate for n<10000 for a 5-dimensional
model (in d=8 even 20000 are not enough). The simulation based test is applied
to select among different R-vine specifications to model the dependency among
exchange rates.


title: Random subgraphs make identification affordable

abstract:
  An identifying code of a graph is a dominating set which uniquely determines
all the vertices by their neighborhood within the code. Whereas graphs with
large minimum degree have small domination number, this is not the case for the
identifying code number (the size of a smallest identifying code), which indeed
is not even a monotone parameter with respect to graph inclusion.
  We show that every graph $G$ with $n$ vertices, maximum degree
$\Delta=\omega(1)$ and minimum degree $\delta\geq c\log{\Delta}$, for some
constant $c>0$, contains a large spanning subgraph which admits an identifying
code with size $O\left(\frac{n\log{\Delta}}{\delta}\right)$. In particular, if
$\delta=\Theta(n)$, then $G$ has a dense spanning subgraph with identifying
code $O\left(\log n\right)$, namely, of asymptotically optimal size. The
subgraph we build is created using a probabilistic approach, and we use an
interplay of various random methods to analyze it. Moreover we show that the
result is essentially best possible, both in terms of the number of deleted
edges and the size of the identifying code.


title: Quantum cosmology from the de Broglie-Bohm perspective

abstract:
  We review the main results that have been obtained in quantum cosmology from
the perspective of the de Broglie-Bohm quantum theory. As it is a dynamical
theory of assumed objectively real trajectories in the configuration space of
the physical system under investigation, this quantum theory is not essentially
probabilistic and dispenses the collapse postulate, turning it suitable to be
applied to cosmology. In the framework of minisuperspace models, we show how
quantum cosmological effects in the de-Broglie-Bohm's approach can avoid the
initial singularity, and isotropize the Universe. We then extend minisuperspace
in order to include linear cosmological perturbations. We present the main
equations which govern the dynamics of quantum cosmological perturbations
evolving in non-singular quantum cosmological backgrounds, and calculate some
of their observational consequences. These results are not known how to be
obtained in other approaches to quantum theory. In the general case of full
superspace, we enumerate the possible structures of quantum space and time that
emerge from the de Broglie-Bohm picture. Finally, we compare some of the
results coming from the de Broglie-Bohm theory with other approaches, and
discuss the physical reasons for some discrepancies that occur.


title: Poincar\'e-Birkhoff theorems in random dynamics

abstract:
  We propose a generalization of the Poincar\'e-Birkhoff Theorem on
area-preserving twist maps to area-preserving twist maps that are random with
respect to an ergodic probability measure. The classical theory is a particular
instance of the random theory we propose.


title: Trudinger-Moser embedding on the hyperbolic space

abstract:
  In [16], we established Trudinger-Moser inequalities for complete noncompact
Riemannian manifold on which the Ricci curvature has lower bound and the
injectivity radius is strictly positive. In this note, we improve those
inequalties when the manifold is the hyperbolic space. The method we used here
is still gluing local estimates.


title: An asymptotic model in acoustics: acoustic drift equations

abstract:
  A rigorous asymptotic procedure with the Mach number as a small parameter is
used to derive the equations of mean flows which coexist and are affected by
the background acoustic waves in the limit of very high Reynolds number.


title: Strong decays of molecular states Zc(+) and Zc'(+)

abstract:
  The two newly observed hidden-charm mesons Zc(+)[3900] and a possible partner
state Zc'(+)[3950] with quantum numbers J(P) = 1(+) are considered as hadronic
molecules composed of bar(D)D* and bar(D)* D*, respectively. We give
predictions for the decay widths of the strong two-body transitions Zc(+) -> H
+ pi(+) and Zc' -> H + pi(+) with H = Psi(nS), hc(mP) in a phenomenological
Lagrangian approach.


title:
Colloquium: Artificial spin ice: Designing and imaging magnetic
  frustration

abstract:
  Frustration in the presence of competing interactions is ubiquitous in the
physical sciences and is a source of degeneracy and disorder, giving rise to
new and interesting physical phenomena. Perhaps nowhere does it occur more
simply than in correlated spin systems, where it has been studied in the most
detail. In the past few years, a new perspective has opened in the study of
frustration through the creation of artificial frustrated magnetic systems.
These materials consist of arrays of lithographically fabricated single-domain
ferromagnetic nanostructures that behave like giant Ising spins. The
nanostructures' interactions can be controlled through appropriate choices of
their geometric properties and arrangement on a (frustrated) lattice. The
degrees of freedom of the material can not only be directly tuned, but also
individually observed. Experimental studies have unearthed intriguing
connections to the out-of-equilibrium physics of disordered systems and
non-thermal granular materials, while revealing strong analogies to (spin) ice
materials and their fractionalized magnetic monopole excitations, lending the
enterprise a distinctly interdisciplinary flavor. The experimental results have
also been closely coupled to theoretical and computational analyses,
facilitated by connections to classic models of frustrated magnetism, whose
hitherto unobserved aspects have here found an experimental realization. We
review the considerable experimental and theoretical progress in this field,
including connections to other frustrated phenomena, and we outline future
vistas for progress in this rapidly expanding field.


title: Most efficient quantum thermoelectric at finite power output

abstract:
  Machines are only Carnot efficient if they are reversible, but then their
power output is vanishingly small. Here we ask, what is the maximum efficiency
of an irreversible device with finite power output? We use a nonlinear
scattering theory to answer this question for thermoelectric quantum systems;
heat engines or refrigerators consisting of nanostructures or molecules that
exhibit a Peltier effect. We find that quantum mechanics places an upper bound
on both power output, and on the efficiency at any finite power. The upper
bound on efficiency equals Carnot efficiency at zero power output, but decays
with increasing power output. It is intrinsically quantum (wavelength
dependent), unlike Carnot efficiency. This maximum efficiency occurs when the
system lets through all particles in a certain energy window, but none at other
energies. A physical implementation of this is discussed, as is the suppression
of efficiency by a phonon heat flow.


title: Radio and gamma-ray emission in faint BL Lacs

abstract:
  The advent of Fermi is changing our understanding on the radio and gamma-ray
emission in Active Galactic Nuclei. In fact, contrary to previous campaigns,
Fermi mission reveals that BL Lac objects are the most abundant emitters in
gamma-ray band. However, since they are relatively weak sources, most of their
parsec scale structure as their multifrequency properties are poorly understood
and/or not systematically investigated. Our main goal is to analyse, using a
multiwavelength approach, the nuclear properties of an homogeneous sample of 42
faint BL Lacs, selected, for the first time in literature, with no constraint
on their radio and gamma-ray flux densities/emission. We began asking and
obtaining new VLBA observations at 8 and 15 GHz for the whole sample. We
derived fundamental parameters as radio flux densities, spectral index
information, and parsec scale structure. Moreover, we investigated their
gamma-ray emission properties using the 2LAT Fermi results. Here, we report our
preliminary results on the radio and gamma-ray properties of this sample of
faint BL Lacs. In the next future, we will complete the multiwavelength
analysis.


title: Noetherianity for infinite-dimensional toric varieties

abstract:
  We consider a large class of monomial maps respecting an action of the
infinite symmetric group, and prove that the toric ideals arising as their
kernels are finitely generated up to symmetry. Our class includes many
important examples where Noetherianity was recently proved or conjectured. In
particular, our results imply Hillar-Sullivant's Independent Set Theorem and
settle several finiteness conjectures due to Aschenbrenner, Martin del Campo,
Hillar, and Sullivant.
  We introduce a matching monoid and show that its monoid ring is Noetherian up
to symmetry. Our approach is then to factorize a more general equivariant
monomial map into two parts going through this monoid. The kernels of both
parts are finitely generated up to symmetry: recent work by
Yamaguchi-Ogawa-Takemura on the (generalized) Birkhoff model provides an
explicit degree bound for the kernel of the first part, while for the second
part the finiteness follows from the Noetherianity of the matching monoid ring.


title: Constraining the intrinsic energy of GRB events

abstract:
  Considering a GRB event as a relativistic ejecta where the relativistic
moving makes radiation become anisotropic, we are able to show that the
required intrinsic energy associated with these events is significantly smaller
than those values commonly presented in literature for an isotropic
distribution of emitted energy. Our results show energy values around $10^{44}$
ergs for Lorentz $\Gamma$ factor $\sim 10$ and around $10^{38}$ ergs for
$\Gamma \sim 300$, values which are more compatible with energies involved in
AGN events rather than those related to the formation of stellar black holes
and hypernovas.


title:
Laser-induced synthesis and decay of Tritium under exposure of solid
  targets in heavy water

abstract:
  The processes of laser-assisted synthesis of Tritium nuclei and their
laser-induced decay in cold plasma in the vicinity of solid targets (Au, Ti,
Se, etc.) immersed into heavy water are experimentally realized at peak laser
intensity of 10E10-10E13 Watts per square centimeter. Initial stages of Tritium
synthesis and their laser-induced beta-decay are interpreted on the basis of
non-elastic interaction of plasma electrons having kinetic energy of 5-10 eV
with nuclei of Deuterium and Tritium, respectively.


title: Towards a Categorical Account of Conditional Probability

abstract:
  This paper presents a categorical account of conditional probability,
covering both the classical and the quantum case. Classical conditional
probabilities are expressed as a certain "triangle-fill-in" condition,
connecting marginal and joint probabilities, in the Kleisli category of the
distribution monad. The conditional probabilities are induced by a map together
with a predicate (the condition). The latter is a predicate in the logic of
effect modules on this Kleisli category.
  This same approach can be transferred to the category of C*-algebras (with
positive unital maps), whose predicate logic is also expressed in terms of
effect modules. Conditional probabilities can again be expressed via a
triangle-fill-in property. In the literature, there are several proposals for
what quantum conditional probability should be, and also there are extra
difficulties not present in the classical case. At this stage, we only describe
quantum systems with classical parametrization.


title:
Large-signal stability conditions for semi-quasi-Z-source inverters:
  switched and averaged models

abstract:
  The recently introduced semi-quasi-Z-source in- verter can be interpreted as
a DC-DC converter whose input- output voltage gain may take any value between
minus infinity and 1 depending on the applied duty cycle. In order to generate
a sinusoidal voltage waveform at the output of this converter, a time-varying
duty cycle needs to be applied. Application of a time-varying duty cycle that
produces large-signal behavior requires careful consideration of stability
issues. This paper provides stability results for both the large-signal
averaged and the switched models of the semi-quasi-Z-source inverter operating
in continuous conduction mode. We show that if the load is linear and purely
resistive then the boundedness and ultimate boundedness of the state
trajectories is guaranteed provided some reasonable operation conditions are
ensured. These conditions amount to keeping the duty cycle away from the
extreme values 0 or 1 (averaged and switched models), and limiting the maximum
PWM switching period (switched model). The results obtained can be used to give
theoretical justification to the inverter operation strategy recently proposed
by Cao et al. in [1].


title: On strongly Gauduchon metrics of compact complex manifolds

abstract:
  In this paper, we study strongly Gauduchon metrics on compact complex
manifolds. We study the cohomology cones SG in the de Rham cohomology groups
generated by all strongly Gauduchon metrics and its direct images under proper
modifications. We also study the moduli of strongly Gauduchon manifolds. We
prove an existence result of strongly Gauduchon metrics on compact complex
manifold which is fibred over a compact complex curve. In particular, if a
compact complex manifold X has a topologically essential fibration over a
compact complex curve, and if the generic fibres satisfy ddbar-lemma, then X
admits strongly Gauduchon metrics.


title: Sets of lengths in maximal orders in central simple algebras

abstract:
  Let $\mathcal O$ be a holomorphy ring in a global field $K$, and $R$ a
classical maximal $\mathcal O$-order in a central simple algebra over $K$. We
study sets of lengths of factorizations of cancellative elements of $R$ into
atoms (irreducibles). In a large majority of cases there exists a transfer
homomorphism to a monoid of zero-sum sequences over a ray class group of
$\mathcal O$, which implies that all the structural finiteness results for sets
of lengths---valid for commutative Krull monoids with finite class group---hold
also true for $R$. If $\mathcal O$ is the ring of algebraic integers of a
number field $K$, we prove that in the remaining cases no such transfer
homomorphism can exist and that several invariants dealing with sets of lengths
are infinite.


title: A note on Rome-Southampton Renormalization with Smeared Gauge Fields

abstract:
  We have calculated continuum limit step scaling functions of bilinear and
four-fermion operators renormalized in a Rome-Southampton scheme using various
smearing prescriptions for the gauge field. Also, for the first time, we have
calculated non-perturbative anomalous dimensions of operators renormalized in a
Rome-Southampton scheme. The effect of such smearing first enters connected
fermionic correlation functions via radiative corrections. We use off-shell
renormalisation as a probe, and observe that the upper edge of the
Rome-Southampton window is reduced by link smearing. This can be interpreted as
arising due to the fermions decoupling from the high momentum gluons and we
observe that the running of operators with the scale at large lattice momenta
shows enhanced lattice artefacts. We find that the effect is greater for HEX
smearing than for Stout smearing, but that in both cases additional care must
be taken when using off-shell renormalisation with smeared gauge fields
compared to thin link simulations.


title: biobambam: tools for read pair collation based algorithms on BAM files

abstract:
  Sequence alignment data is often ordered by coordinate (id of the reference
sequence plus position on the sequence where the fragment was mapped) when
stored in BAM files, as this simplifies the extraction of variants between the
mapped data and the reference or of variants within the mapped data. In this
order paired reads are usually separated in the file, which complicates some
other applications like duplicate marking or conversion to the FastQ format
which require to access the full information of the pairs. In this paper we
introduce biobambam, an API for efficient BAM file reading supporting the
efficient collation of alignments by read name without performing a complete
resorting of the input file and some tools based on this API performing tasks
like marking duplicate reads and conversion to the FastQ format. In comparison
with previous approaches to problems involving the collation of alignments by
read name like the BAM to FastQ or duplication marking utilities in the Picard
suite the approach of biobambam can often perform an equivalent task more
efficiently in terms of the required main memory and run-time.


title: Intrinsic noise and discrete-time processes

abstract:
  A general formalism is developed to construct a Markov chain model that
converges to a one-dimensional map in the infinite population limit. Stochastic
fluctuations are therefore internal to the system and not externally specified.
For finite populations an approximate Gaussian scheme is devised to describe
the stochastic fluctuations in the non-chaotic regime. More generally, the
stochastic dynamics can be captured using a stochastic difference equation,
derived through an approximation to the Markov chain. The scheme is
demonstrated using the logistic map as a case study.


title:
Dipole transitions in the bound rotational-vibrational spectrum of the
  heteronuclear molecular ion HD$^+$

abstract:
  The non-relativistic three-body Schr\"odinger equation of the heteronuclear
molecular ion HD$^+$ is solved in perimetric coordinates using the
Lagrange-mesh method. Energies and wave functions of the four lowest
vibrational bound or quasibound states $v=0-3$ are calculated for total orbital
momenta from 0 to 47. Energies are given with an accuracy from about 12 digits
for the lowest vibrational level to at least 9 digits for the third vibrational
excited level. With a simple calculation using the corresponding wave
functions, accurate dipole transition probabilities per time unit between those
levels are given over the whole $v=0-3$ rotational bands. Results are presented
with six significant figures.


title: FLAMES and XSHOOTER spectroscopy along the two BSS sequences of M30

abstract:
  We present spectroscopic observations acquired with FLAMES and XSHOOTER at
the Very Large Telescope for a sample of 15 Blue Straggler Stars (BSSs) in the
globular cluster (GC) M30. The targets have been selected to sample the two BSS
sequences discovered, with 7 BSSs along the blue sequence and 8 along the red
one. No difference in the kinematical properties of the two groups of BSSs has
been found. In particular, almost all the observed BSSs have projected
rotational velocity lower than ~30 km/s, with only one (blue) fast rotating BSS
(>90 km/s), identified as a W UMa binary. This rotational velocity distribution
is similar to those obtained in 47 Tucanae and NGC 6397, while M4 remains the
only GC studied so far harboring a large fraction of fast rotating BSSs. All
stars hotter than ~7800 K (regardless of the parent BSS sequence) show iron
abundances larger than those measured from normal cluster stars, with a
clearcut trend with the effective temperature. This behaviour suggests that
particle trasport mechanisms driven by radiative levitation occur in the
photosphere of these stars, as already observed for the BSSs in NGC 6397.
Finally, 4 BSSs belonging to the red sequence (not affected by radiative
levitation) show a strong depletion of [O/Fe], with respect to the abundance
measured in Red Giant Branch and Horizontal Branch stars. This O-depletion is
compatible with the chemical signature expected in BSSs formed by mass transfer
processes in binary systems, in agreement with the mechanism proposed for the
formation of BSSs in the red sequence.


title: Strongly-Correlated Thermoelectric Transport beyond Linear Response

abstract:
  We investigate nonlinear thermoelectric transport through quantum impurity
systems with strong on-site interactions. We show that the steady-state
transport through interacting quantum impurities in contact with electron
reservoirs at significantly different temperatures can be captured by an
effective-equilibrium density matrix, expressed compactly in terms of the
Lippmann-Schwinger operators of the system. In addition, the reservoirs can be
maintained at arbitrary chemical potentials. The interplay between the
temperature gradient and bias voltage gives rise to a non-trivial breaking of
particle-hole symmetry in the strongly correlated regime, manifest in the
Abrikosov-Suhl localized electron resonance. This purely many-body effect,
which is in agreement with experimental results, is beyond the purview of
mean-field arguments.


title:
Identifying the electronic character and role of the Mn states in the
  valence band of (Ga,Mn)As

abstract:
  We report high-resolution hard x-ray photoemission spectroscopy results on
(Ga,Mn)As films as a function of Mn doping. Supported by theoretical
calculations we identify, over the entire 1% to 13% Mn doping range, the
electronic character of the states near the top of the valence band.
Magnetization and temperature dependent core-level photoemission spectra reveal
how the delocalized character of the Mn states enables the bulk ferromagnetic
properties of (Ga,Mn)As.


title: Kernel Mean Estimation and Stein's Effect

abstract:
  A mean function in reproducing kernel Hilbert space, or a kernel mean, is an
important part of many applications ranging from kernel principal component
analysis to Hilbert-space embedding of distributions. Given finite samples, an
empirical average is the standard estimate for the true kernel mean. We show
that this estimator can be improved via a well-known phenomenon in statistics
called Stein's phenomenon. After consideration, our theoretical analysis
reveals the existence of a wide class of estimators that are better than the
standard. Focusing on a subset of this class, we propose efficient shrinkage
estimators for the kernel mean. Empirical evaluations on several benchmark
applications clearly demonstrate that the proposed estimators outperform the
standard kernel mean estimator.


title:
The size of quantum superpositions as measured with "classical"
  detectors

abstract:
  We propose a criterion which defines whether a superposition of two photonic
components is macroscopic. It is based on the ability to discriminate these
components with a particular class of "classical" detectors, namely a photon
number measurement with a resolution coarse-grained by noise. We show how our
criterion can be extended to a measure of the size of macroscopic
superpositions by quantifying the amount of noise that can be tolerated and
taking the distinctness of two Fock states differing by N photons as a
reference. After applying our measure to several well-known examples, we
demonstrate that the superpositions which meet our criterion are very sensitive
to phase fluctuations. This suggests that quantifying the macroscopicity of a
superposition state through the distinguishability of its components with
"classical" detectors is not only a natural measure but also explains why it is
difficult to observe superpositions at the macroscopic scale.


title:
Effect of screening on spectroscopic properties of Li-like ions in
  plasma environment

abstract:
  This work presents accurate {\it ab initio} investigations of various
spectroscopic properties of a few Li-like ions in presence of a plasma
environment within the Debye screening potential. The coupled-cluster theory in
the relativistic framework has been employed to compute ionization potentials,
excitation energies, electric dipole oscillator strengths, and electric
quadrupole transition probabilities of Li-like C$^{3+}$, N$^{4+}$, and O$^{5+}$
ions. The unretarded Breit interaction has been implemented to increase the
accuracy of the calculations. The effects of ion density and temperature on the
ionization potentials, excitation energies, electric dipole oscillator
strengths, and electric quadrupole transition probabilities have been
investigated in the plasma environment. It is found that the plasma screening
leads to a sharp decrease in the ionization potential as the screening strength
increases. With increasing strength, the oscillator strengths associated with
2$s ^{2}S_{1/2}$$\rightarrow2 p ^{2}P_{1/2, 3/2}$ transitions increase, whereas
the transition probabilities associated with 3$d ^2D_{3/2, 5/2}$$\rightarrow2 s
^2S_{1/2}$ transitions decrease.

categories: physics.atom-ph cond-mat.mes-hall physics.chem-ph physics.plasm-ph


title: Optimization for Mass Hierarchy

abstract:
  The Delta m^2_13 oscillation frequency for reactor neutrinos differs by 6.4%
between normal and inverted mass hierarchy. This frequency difference
accumulates to a phase difference over distance and time. The optimal distance
is when the maximum phase difference between hierarchies occurs near the peak
in the observable reactor neutrino spectrum. Added citations to some related
recent work.


title: V-BOINC: The Virtualization of BOINC

abstract:
  The Berkeley Open Infrastructure for Network Computing (BOINC) is an open
source client-server middleware system created to allow projects with large
computational requirements, usually set in the scientific domain, to utilize a
technically unlimited number of volunteer machines distributed over large
physical distances. However various problems exist deploying applications over
these heterogeneous machines using BOINC: applications must be ported to each
machine architecture type, the project server must be trusted to supply
authentic applications, applications that do not regularly checkpoint may lose
execution progress upon volunteer machine termination and applications that
have dependencies may find it difficult to run under BOINC.
  To solve such problems we introduce virtual BOINC, or V-BOINC, where virtual
machines are used to run computations on volunteer machines. Application
developers can then compile their applications on a single architecture,
checkpointing issues are solved through virtualization API's and many security
concerns are addressed via the virtual machine's sandbox environment. In this
paper we focus on outlining a unique approach on how virtualization can be
introduced into BOINC and demonstrate that V-BOINC offers acceptable
computational performance when compared to regular BOINC. Finally we show that
applications with dependencies can easily run under V-BOINC in turn increasing
the computational potential volunteer computing offers to the general public
and project developers.


title: Moving Frames and Noether's Conservation Laws - the General Case

abstract:
  In recent works, the authors considered various Lagrangians, which are
invariant under a Lie group action, in the case where the independent variables
are themselves invariant. Using a moving frame for the Lie group action, they
showed how to obtain the invariantized Euler-Lagrange equations and the space
of conservation laws in terms of vectors of invariants and the adjoint
representation of a moving frame.
  In this paper, we show how these calculations extend to the general case
where the independent variables may participate in the action. We take for our
main expository example the standard linear action of SL(2) on the two
independent variables. This choice is motivated by applications to variational
fluid problems which conserve potential vorticity. We also give the results for
Lagrangians invariant under the standard linear action of SL(3) on the three
independent variables.


title: Parovicenko spaces with structures

abstract:
  We study an analogue of the Parovicenko property in categories of compact
spaces with additional structures. In particular, we present an internal
characterization of this property in the class of compact median spaces.


title:
Efficient separation of the orbital angular momentum eigenstates of
  light

abstract:
  Orbital angular momentum (OAM) of light is an attractive degree of freedom
for funda- mentals studies in quantum mechanics. In addition, the discrete
unbounded state-space of OAM has been used to enhance classical and quantum
communications. Unambiguous mea- surement of OAM is a key part of all such
experiments. However, state-of-the-art methods for separating single photons
carrying a large number of different OAM values are limited to a theoretical
separation efficiency of about 77 percent. Here we demonstrate a method which
uses a series of unitary optical transformations to enable the measurement of
lights OAM with an experimental separation efficiency of more than 92 percent.
Further, we demonstrate the separation of modes in the angular position basis,
which is mutually unbiased with respect to the OAM basis. The high degree of
certainty achieved by our method makes it particu- larly attractive for
enhancing the information capacity of multi-level quantum cryptography systems.


title:
Revealing the heavily obscured AGN population of High Redshift 3CRR
  Sources with Chandra X-ray Observations

abstract:
  Chandra observations of a complete, flux-limited sample of 38 high-redshift
(1<z<2), low-frequency selected (and so unbiased in orientation) 3CRR radio
sources are reported. The sample includes 21 quasars (= broad line radio
galaxies) and 17 narrow line radio galaxies (NLRGs) with matched 178 MHz radio
luminosity (log L_R ~ 44-45). The quasars have high radio core-fraction, high
X-ray luminosities (log L_X ~ 45-46) and soft X-ray hardness ratios (HR ~ -0.5)
indicating low obscuration. The NLRGs have lower core-fraction, lower apparent
X-ray luminosities (log L_X ~ 43-45) and mostly hard X-ray hardness ratios
(HR>0) indicating obscuration (log N_H ~ 22-24 cm^-2). These properties and the
correlation between obscuration and radio core-fraction are consistent with
orientation-dependent obscuration as in Unification models. About half the
NLRGs have soft X-ray hardness ratios and/or high [OIII] emission line to X-ray
luminosity ratio suggesting obscuration by Compton thick (CT) material so that
scattered nuclear or extended X-ray emission dominates (as in NGC1068). The
ratios of unobscured to Compton-thin (10^{22}< N_H(int) < 1.5 x 10^{24} cm^-2)
to CT (N_H(int) > 1.5 x 10^{24} cm^-2) is 2.5:1.4:1 in this high luminosity,
radio-selected sample. The obscured fraction is 0.5, higher than is typically
reported for AGN at comparable luminosities from multi-wavelength surveys
(0.1-0.3). Assuming random nuclear orientation, the unobscured half-opening
angle of the disk/wind/torus structure is ~ 60deg and the obscuring material
covers 30deg of which ~ 12deg is Compton thick. The multi-wavelength properties
reveal that many NLRGs have intrinsic absorption 10-1000x higher than indicated
by their X-ray hardness ratios, and their true L_X values are ~10--100x larger
than the hardness-ratio absorption corrections would indicate.


title: Stochastic Turing Patterns for systems with one diffusing species

abstract:
  The problem of pattern formation in a generic two species reaction--diffusion
model is studied, under the hypothesis that only one species can diffuse. For
such a system, the classical Turing instability cannot take place. At variance,
by working in the generalized setting of a stochastic formulation to the
inspected problem, Turing like patterns can develop, seeded by finite size
corrections. General conditions are given for the stochastic Turing patterns to
occur. The predictions of the theory are tested for a specific case study.


title:
Integral inequalities of Hermite-Hadamard type for
  $(\alpha,m)$-GA-convex functions

abstract:
  In the paper, the authors introduce a notion "$(\alpha,m)$-GA-convex
functions" and establish some integral inequalities of Hermite-Hadamard type
for $(\alpha,m)$-GA-convex functions.


title:
Sign cancellation and scaling in the vertical component of velocity and
  vorticity in rotating turbulence

abstract:
  We study sign changes and scaling laws in the Cartesian components of the
velocity and vorticity of rotating turbulence, in the helicity, and in the
components of vertically-averaged fields. Data for the analysis is provided by
high-resolution direct numerical simulations of rotating turbulence with
different forcing functions, with up to 1536^3 grid points, with Reynolds
numbers between ~1100 and ~5100, and with moderate Rossby numbers between ~0.06
and ~8. When rotation is negligible, all Cartesian components of the velocity
show similar scaling, in agreement with the expected isotropy of the flow.
However, in the presence of rotation only the vertical components of the fields
show clear scaling laws, with evidence of possible sign singularity in the
limit of infinite Reynolds number. Horizontal components of the velocity are
smooth and do not display rapid fluctuations for arbitrarily small scales. The
vertical velocity and vorticity, as well as the vertically-averaged vertical
velocity and vorticity, show the same scaling within error bars, in agreement
with theories that predict that these quantities have the same dynamical
equation for very strong rotation.


title: Simple zeros of modular L-functions

abstract:
  Assuming the generalized Riemann hypothesis, we prove quantitative estimates
for the number of simple zeros on the critical line for the L-functions
attached to classical holomorphic newforms.


title:
Ab initio studies of ionization potentials of hydrated hydroxide and
  hydronium

abstract:
  The ionization potential distributions of hydrated hydroxide and hydronium
are computed with many-body approach for electron excitations with
configurations generated by {\it ab initio} molecular dynamics. The
experimental features are well reproduced and found to be closely related to
the molecular excitations. In the stable configurations, the ionization
potential is mainly perturbed by water molecules within the first solvation
shell. On the other hand, electron excitation is delocalized on both proton
receiving and donating complex during proton transfer, which shifts the
excitation energies and broadens the spectra for both hydrated ions.


title: On Balazard, Saias, and Yor's equivalence to the Riemann Hypothesis

abstract:
  Balazard, Saias, and Yor proved that the Riemann Hypothesis is equivalent to
a certain weighted integral of the logarithm of the Riemann zeta-function along
the critical line equaling zero. Assuming the Riemann Hypothesis, we
investigate the rate at which a truncated version of this integral tends to
zero, answering a question of Borwein, Bradley, and Crandall and disproving a
conjecture of the same authors. A simple modification of our techniques gives a
new proof of a classical Omega theorem for the function S(t) in the theory of
the Riemann zeta-function.


title: Intertwining diffusions and wave equations

abstract:
  We develop a general theory of intertwined diffusion processes of any
dimension. Our main result gives an SDE characterization of all possible
intertwinings of diffusion processes and shows that they correspond to
nonnegative solutions of hyperbolic partial differential equations. For
example, solutions of the classical wave equation correspond to the
intertwinings of two Brownian motions. The theory allows us to unify many older
examples of intertwinings, such as the process extension of the beta-gamma
algebra, with more recent examples such as the ones arising in the study of
two-dimensional growth models. We also find many new classes of intertwinings
and develop systematic procedures for building more complex intertwinings by
combining simpler ones. In particular, `orthogonal waves' combine
unidimensional intertwinings to produce multidimensional ones. Connections with
duality, time reversals and Doob's h-transforms are also explored.


title:
Development and Study of Different Muon Track Reconstruction Algorithms
  for the Level-1 Trigger for the CMS Muon Upgrade with GEM Detectors

abstract:
  In the upcoming years, with the upgrade of the LHC to higher luminosities,
CMS will be subject to an increasing flux of particles, especially in its most
forward region, at | \eta | > 1.6. To consolidate the muon spectrometer of CMS
and increase redundancy, the CMS GEM collaboration proposes to instrument the
1.6 < | \eta | < 2.1 region, originally foreseen to be equipped with RPC, with
Triple-GEM detectors. This technology has proven to remain efficient under high
fluxes and meets the requirements of CMS.
  This work, using simulations, studies three track reconstruction algorithms
intended to be installed in the first selection stage of CMS for Triple-GEM
detectors: a Least Squares fit, a standard Kalman filter, and a modified Kalman
filter. A comparative analysis is performed between the results obtained with
Triple-GEM detectors and those yielded by the actual system in order to
quantity the improvements made to the CMS muon spectrometer and to the CMS
trigger system.


title: Extinction profile of complete non-compact solutions to the Yamabe flow

abstract:
  This work addresses the {\em singularity formation} of complete non-compact
solutions to the conformally flat Yamabe flow whose conformal factors have {\em
cylindrical behavior at infinity}. Their singularity profiles happen to be {\em
Yamabe solitons}, which are {\em self-similar solutions} to the fast diffusion
equation satisfied by the conformal factor of the evolving metric. The
self-similar profile is determined by the second order asymptotics at infinity
of the initial data which is matched with that of the corresponding
self-similar solution. Solutions may become extinct at the extinction time $T$
of the cylindrical tail or may live longer than $T$. In the first case the
singularity profile is described by a {\em Yamabe shrinker} that becomes
extinct at time $T$. In the second case, the singularity profile is described
by a {\em singular} Yamabe shrinker slightly before $T$ and by a matching {\em
Yamabe expander} slightly after $T$ .


title: Quantum Systems and Resolvent Algebras

abstract:
  This survey article is concerned with the modeling of the kinematical
structure of quantum systems in an algebraic framework which eliminates certain
conceptual and computational difficulties of the conventional approaches.
Relying on the Heisenberg picture it is based on the resolvents of the basic
canonically conjugate operators and covers finite and infinite quantum systems.
The resulting C*-algebras, the resolvent algebras, have many desirable
properties. On one hand they encode specific information about the dimension of
the respective quantum system and have the mathematically comfortable feature
of being nuclear, and for finite dimensional systems they are even postliminal.
This comes along with a surprisingly simple structure of their representations.
On the other hand, they are a convenient framework for the study of interacting
as well as constrained quantum systems since they allow the direct application
of C*-algebraic methods which often simplify the analysis. Some pertinent facts
are illustrated by instructive examples.


title: Matrix Elements of Lorentzian Hamiltonian Constraint in LQG

abstract:
  The Hamiltonian constraint is the key element of the canonical formulation of
LQG coding its dynamics. In Ashtekar-Barbero variables it naturally splits into
the so called Euclidean and Lorentzian parts. However, due to the high
complexity of this operator, only the matrix elements of the Euclidean part
have been considered so far. Here we evaluate the action of the full
constraint, including the Lorentzian part. The computation requires an heavy
use of SU(2) recoupling theory and several tricky identities among n-j symbols
are used to find the final result: these identities, together with the
graphical calculus used to derive them, also simplify the Euclidean constraint
and are of general interest in LQG computations.


title:
Proof of two conjectures on correlation inequalities for one class of
  monotone functions

abstract:
  We prove two conjectures on correlation inequalities for functions that are
linear combinations of unimodal Boolean monotone nondecreasing functions


title: Simple, broadband, optical spatial cloaking of very large objects

abstract:
  We demonstrate three simple cloaking devices that can hide very large spatial
objects over the entire visible spectrum using only passive, off-the-shelf
optics. The cloaked region for all of the devices exceeds 10^6 mm3 with the
largest exceeding 10^8 mm3. Although uni-directional, these cloaks can hide the
cloaked object, even if the object is transversely or self-illuminated. Owing
to the small usable solid angle, but simple scaling, these cloaks may be of
value in hiding small field-of-view objects such as mid- to high-earth orbit
satellites.


title: Tutte polynomials and a stronger version of the Akiyama-Harary problem

abstract:
  Can a non self-complementary graph have the same chromatic polynomial as its
complement? The answer to this question of Akiyama and Harrary is positive and
was given by J. Xu and Z. Liu. They conjectured that every such graph has the
same degree sequence as its complement. In this paper we show that there are
infinitely many graphs for which this conjecture does not hold. We then solve a
more general variant of the Akiyama-Harary problem by showing that there exists
infinitely many non self-complementary graphs having the same Tutte polynomial
as their complements.


title:
Joint Signal and Channel State Information Compression for the Backhaul
  of Uplink Network MIMO Systems

abstract:
  In network MIMO cellular systems, subsets of base stations (BSs), or remote
radio heads, are connected via backhaul links to central units (CUs) that
perform joint encoding in the downlink and joint decoding in the uplink.
Focusing on the uplink, an effective solution for the communication between BSs
and the corresponding CU on the backhaul links is based on compressing and
forwarding the baseband received signal from each BS. In the presence of
ergodic fading, communicating the channel state information (CSI) from the BSs
to the CU may require a sizable part of the backhaul capacity. In a prior work,
this aspect was studied by assuming a Compress-Forward-Estimate (CFE) approach,
whereby the BSs compress the training signal and CSI estimation takes place at
the CU. In this work, instead, an Estimate-Compress-Forward (ECF) approach is
investigated, whereby the BSs perform CSI estimation and forward a compressed
version of the CSI to the CU. This choice is motivated by the information
theoretic optimality of separate estimation and compression. Various ECF
strategies are proposed that perform either separate or joint compression of
estimated CSI and received signal. Moreover, the proposed strategies are
combined with distributed source coding when considering multiple BSs.
"Semi-coherent" strategies are also proposed that do not convey any CSI or
training information on the backhaul links. Via numerical results, it is shown
that a proper design of ECF strategies based on joint received signal and
estimated CSI compression or of semi-coherent schemes leads to substantial
performance gains compared to more conventional approaches based on
non-coherent transmission or the CFE approach.


title:
Investigations of the torque anomaly in an annular sector. I. Global
  calculations, scalar case

abstract:
  In an attempt to understand a recently discovered torque anomaly in quantum
field theory with boundaries, we calculate the Casimir energy and torque of a
scalar field subject to Dirichlet boundary conditions on an annular sector
defined by two coaxial cylinders intercut by two planes through the axis. In
this model the particularly troublesome divergence at the cylinder axis does
not appear, but new divergences associated with the curved boundaries are
introduced. All the divergences associated with the volume, the surface area,
the corners, and the curvature are regulated by point separation either in the
direction of the axis of the cylinder or in the (Euclidean) time; the full
divergence structure is isolated, and the remaining finite energy and torque
are extracted. Formally, only the regulator based on axis splitting yields the
expected balance between energy and torque. Because of the logarithmic
curvature divergences, there is an ambiguity in the linear dependence of the
energy on the wedge angle; if the terms constant and linear in this angle are
removed by a process of renormalization, the expected torque-energy balance is
preserved.


title: The Classical Family Algebra of the Adjoint Representation of $sl(n)$

abstract:
  For the simple Lie algebra $g = sl(n,C)$ we we find a set of generators and
relations for the classical family algebra $(End(g)\otimes S(g))^G$ as an
algebra over the ring $I(g)$. From these we can then determine a $I(g)$-linear
basis of the family algebra, and thus the generalized exponents of the
irreducible components of $End(g)$ viewed as a $g$-module.


title: A Conceptual Shift to Rectify a Defect in the Lorentz-Dirac Equation

abstract:
  In his analysis of the Classical Theory of Radiating Electrons, Dirac (1938)
draws attention to the characteristic instability of solutions to the third
order equation of motion. He remarks that changing the sign of the self-force
eliminates the runaway solutions and gives `reasonable behaviour'. Dirac
rejects such a change and proceeds with an ad hoc modification to the solutions
of the initial value problem that is not consistent with the principle of
causality. We argue that his reasons for rejecting the change of sign are
invalid on both physical and mathematical grounds.
  The conceptual shift is to treat the physical particle as a composite of the
source particle and the energy-momentum that is reversibly generated in its
self-field by its motion. The reversibly generated energy in the self-field is
interpreted as kinetic energy, and the changes that follow result in Dirac's
change of sign. Several exact solutions to the new equation of motion and its
linearisation are given. For a particle in orbital motion the self-force
enables the applied force to generate radiation and kinetic energy in the
self-field that results in an outward spiral motion. The theory is consistent
with all well-established principles of physics, including the principle of
causality.


title: Exciton dynamics in emergent Rydberg lattices

abstract:
  The dynamics of excitons in a one-dimensional ensemble with partial spatial
order are studied. During optical excitation, cold Rydberg atoms spontaneously
organize into regular spatial arrangements due to their mutual interactions.
This emergent lattice is used as the starting point to study resonant energy
transfer triggered by driving a $nS$ to $n^\prime P$ transition using a
microwave field. The dynamics are probed by detecting the survival probability
of atoms in the $nS$ Rydberg state. Experimental data qualitatively agree with
our theoretical predictions including the mapping onto XXZ spin model in the
strong-driving limit. Our results suggest that emergent Rydberg lattices
provide an ideal platform to study coherent energy transfer in structured media
without the need for externally imposed potentials.


title: Prescribed subintegral extensions of local Noetherian domains

abstract:
  We show how subintegral extensions of certain local Noetherian domains $S$
can be constructed with specified invariants including reduction number,
Hilbert function, multiplicity and local cohomology. The construction behaves
analytically like Nagata idealization but rather than a ring extension of $S$,
it produces a subring $R$ of $S$ such that $R \subseteq S$ is subintegral.


title: Quadrature phase interferometer for high resolution force spectroscopy

abstract:
  In this article, we present a deflection measurement setup for Atomic Force
Microscopy (AFM). It is based on a quadrature phase differential
interferometer: we measure the optical path difference between a laser beam
reflecting above the cantilever tip and a reference beam reflecting on the
static base of the sensor. A design with very low environmental susceptibility
and another allowing calibrated measurements on a wide spectral range are
described. Both enable a very high resolution (down to
$\SI{2.5E-15}{m/\sqrt{Hz}}$), illustrated by thermal noise measurements on AFM
cantilevers. They present an excellent long-term stability, and a constant
sensitivity independent of the optical phase of the interferometer. A quick
review shows that our precision is equaling or out-performing the best results
reported in the literature, but for a much larger deflection range, up to a few
$\SI{}{\micro m}$.


title:
Cavity optomechanics with synthetic Landau levels of ultra cold Fermi
  gas

abstract:
  Ultra cold fermionic atoms placed in a synthetic magnetic field arrange
themselves in Landau levels. We theoretically study the optomechanical
interaction between the light field and collective excitations of such
fermionic atoms in synthetic magnetic field by placing them in side a Fabry
Perot cavity. We derive the effective hamiltonian for particle hole excitations
from a filled Landau level using a bosonization technique and obtain an
expression for the cavity transmission spectrum. Using this we show that the
cavity transmission spectrum demonstrates cold atom analogue of Subnikov de
Hass oscillation in electronic condensed matter systems. We discuss the
experimental consequences for this oscillation for such system and the related
optical bistability.


title:
Inversion and tight focusing of Airy pulses under the action of
  third-order dispersion

abstract:
  By means of direct simulations and theoretical analysis, we study the
nonlinear propagation of truncated Airy pulses in an optical fiber exhibiting
both anomalous second-order and strong positive third-order dispersions. It is
found that the Airy pulse first reaches a finite-size focal area as determined
by the relative strength of the two dispersion terms, and then undergoes an
inversion transformation such that it continues to travel with an opposite
acceleration. The system notably features tight focusing if the third-order
dispersion is a dominant factor. These effects are partially reduced by a Kerr
nonlinearity.


title:
Exact Axisymmetric Solutions of the Maxwell Equations in a Nonlinear
  Nondispersive Medium

abstract:
  The features of propagation of intense waves are of great interest for theory
and experiment in electrodynamics and acoustics. The behavior of nonlinear
waves in a bounded volume is of especial importance and, at the same time, is
an extremely complicated problem. It seems almost impossible to find a rigorous
solution to such a problem even for any model of nonlinearity. We obtain the
first exact solution of this type. We present a new method for deriving exact
solutions of the Maxwell equations in a nonlinear medium without dispersion and
give examples of the obtained solutions that describe propagation of
cylindrical electromagnetic waves in a nonlinear nondispersive medium and free
electromagnetic oscillations in a cylindrical cavity resonator filled with such
a medium.


title: New Finsler Package

abstract:
  The book "Handbook of Finsler geometry" has been included with a CD
containing an elegant Maple package, FINSLER, for calculations in Finsler
geometry. Using this package, an example concerning a Finsler generalization of
Einstein's vacuum field equations was treated. In this example, the calculation
of the components of the hv-curvature of Cartan connection leads to wrong
expressions. On the other hand, the FINSLER package works only in dimension
four. We introduce a new Finsler package in which we fix the two problems and
solve them. Moreover, we extend this package to compute not only the geometric
objects associated with Cartan connection but also those associated with
Berwald, Chern and Hashiguchi connections in any dimension. These improvements
have been illustrated by a concrete example. Furthermore, the problem of
simplifying tensor expressions is treated. This paper is intended to make
calculations in Finsler geometry more easier and simpler.


title: Geometric Langlands Correspondence Near Opers

abstract:
  We extend the categorical geometric Langlands correspondence from the locus
of opers in the stack of de Rham local systems on a smooth projective algebraic
curve to the formal neighborhood of opers (for any semi-simple complex
algebraic group).


title: Generalized CP symmetries in Delta(27) flavor models

abstract:
  We classify explicitly all the possible generalized CP (GCP) symmetries that
are definable in $\Delta(27)$ flavor models. In total, only 12 transformations
are possible. We also show interesting consequences of considering some of them
as residual symmetries of the neutrino sector.


title: A Nearly Polar Orbit for the Extrasolar Hot Jupiter WASP-79b

abstract:
  We report the measurement of a spin-orbit misalignment for WASP-79b, a
recently discovered, bloated transiting hot Jupiter from the WASP survey. Data
were obtained using the CYCLOPS2 optical-fiber bundle and its simultaneous
calibration system feeding the UCLES spectrograph on the Anglo-Australian
Telescope. We have used the Rossiter-McLaughlin effect to determine the
sky-projected spin-orbit angle to be lambda = -106+19-13 degrees. This result
indicates a significant misalignment between the spin axis of the host star and
the orbital plane of the planet -- the planet being in a nearly polar orbit.
WASP-79 is consistent with other stars that have Teff > 6250K and host hot
Jupiters in spin-orbit misalignment.


title:
Experimental demonstration of quantum digital signatures using
  phase-encoded coherent states of light

abstract:
  Digital signatures are frequently used in data transfer to prevent
impersonation, repudiation and message tampering. Currently used classical
digital signature schemes rely on public key encryption techniques, where the
complexity of so-called "one-way" mathematical functions is used to provide
security over sufficiently long timescales. No mathematical proofs are known
for the long-term security of such techniques. Quantum digital signatures offer
a means of sending a message which cannot be forged or repudiated, with
security verified by information-theoretical limits and quantum mechanics. Here
we demonstrate an experimental system which distributes quantum signatures from
one sender to two receivers and enables message sending ensured against forging
and repudiation. Additionally, we analyse the security of the system in some
typical scenarios. The system is based on the interference of phase encoded
coherent states of light and our implementation utilises polarisation
maintaining optical fibre and photons with a wavelength of 850 nm.


title:
Long-range Order in One-dimensional Spinless Fermi Gas with Attractive
  Dipole-Dipole Interaction

abstract:
  One-dimensional spinless Fermi gas with attractive dipole-dipole interaction
is investigated. Results obtained show when the interaction is weak, the
excitation spectrum is linear and the superconducting correlation function
decays as power law, indicating the validity of the Tomonaga-Luttinger (TL)
liquid picture. However, when the interaction reaches a critical value, the
excitation spectrum is nonlinear and the superconducting correlation function
keeps finite for infinity separation, indicating real long-range order
established and the breakdown of the TL liquid picture. We prove that the
existence of long-range order is not in contradiction with the Hohenberg
theorem and show that this system is related to the Kitaev toy model,
therefore, it has potential applications for the future topological quantum
computation.


title:
Approximations of quantum-graph vertex couplings by singularly scaled
  potentials

abstract:
  We investigate the limit properties of a family of Schr\"odinger operators of
the form $H_\varepsilon= -\frac{\mathrm{d}^2}{\mathrm{d}x^2}+
\frac{\lambda(\varepsilon)}{\varepsilon^2}Q \big(\frac{x}{\varepsilon}\big)$
acting on $n$-edge star graphs with Kirchhoff conditions imposed at the vertex.
The real-valued potential $Q$ is supposed to have compact support and
$\lambda(\cdot)$ to be analytic around $\varepsilon=0$ with $\lambda(0)=1$. We
show that if the operator has a zero-energy resonance of order $m$ for
$\varepsilon=1$ and $\lambda(1)=1$, in the limit $\varepsilon\to 0$ one obtains
the Laplacian with a vertex coupling depending on $1+\frac12 m(2n-m+1)$
parameters. We prove the norm-resolvent convergence as well as the convergence
of the corresponding on-shell scattering matrices. The obtained vertex
couplings are of scale-invariant type provided $\lambda'(0)=0$; otherwise the
scattering matrix depends on energy and the scaled potential becomes
asymptotically opaque in the low-energy limit.


title: Nonabelian Dark Matter with Resonant Annihilation

abstract:
  We construct a model based on an extra gauge symmetry, SU(2)_X x U(1)_{B-L},
which can provide gauge bosons to serve as weakly-interacting massive particle
dark matter. The stability of the dark matter is naturally guaranteed by a
discrete Z_2 symmetry that is a subgroup of SU(2)_X. The dark matter interacts
with standard model fermions by exchanging gauge bosons which are linear
combinations of SU(2)_X x U(1)_{B-L} gauge bosons. With the appropriate choice
of representation for the new scalar multiplet whose vacuum expectation value
spontaneously breaks the SU(2)_X symmetry, the relation between the new gauge
boson masses can naturally lead to resonant pair annihilation of the dark
matter. After exploring the parameter space of the new gauge couplings subject
to constraints from collider data and the observed relic density, we use the
results to evaluate the cross section of the dark matter scattering off
nucleons and compare it with data from the latest direct detection experiments.
We find allowed parameter regions that can be probed by future direct searches
for dark matter and LHC searches for new particles.


title:
On integral points on biquadratic curves and near-multiples of squares
  in Lucas sequences

abstract:
  We describe an algorithmic reduction of the search for integral points on a
curve y^2 = ax^4 + bx^2 + c with nonzero ac(b^2-4ac) to solving a finite number
of Thue equations. While existence of such reduction is anticipated from
arguments of algebraic number theory, our algorithm is elementary and to best
of our knowledge is the first published algorithm of this kind. In combination
with other methods and powered by existing software Thue equations solvers, it
allows one to efficiently compute integral points on biquadratic curves.
  We illustrate this approach with a particular application of finding
near-multiples of squares in Lucas sequences. As an example, we establish that
among Fibonacci numbers only 2 and 34 are of the form 2m^2+2; only 1, 13, and
1597 are of the form m^2-3; and so on.
  As an auxiliary result, we also give an algorithm for solving a Diophantine
equation k^2 = f(m,n)/g(m,n) in integers m,n,k, where f and g are homogeneous
quadratic polynomials.


title:
Self-Force and Green Function in Schwarzschild spacetime via Quasinormal
  Modes and Branch Cut

abstract:
  The motion of a small compact object in a curved background spacetime
deviates from a geodesic due to the action of its own field, giving rise to a
self-force. This self-force may be calculated by integrating the Green function
for the wave equation over the past worldline of the small object. We compute
the self-force in this way for the case of a scalar charge in Schwarzschild
spacetime, making use of the semi-analytic method of matched Green function
expansions. Inside a local neighbourhood of the compact object, this method
uses the Hadamard form for the Green function in order to render regularization
trivial. Outside this local neighbourhood, we calculate the Green function
using a spectral decomposition into poles (quasinormal modes) and a branch cut
integral in the complex-frequency plane. We show that both expansions overlap
in a sufficiently large matching region for an accurate calculation of the
self-force to be possible. The scalar case studied here is a useful and
illustrative toy-model for the gravitational case, which serves to model
astrophysical binary systems in the extreme mass-ratio limit.


title:
Open Charm Production in $p + p$ and Pb + Pb collisions at the CERN
  Large Hadron Collider

abstract:
  Effects of strong longitudinal colour electric fields (SCF), shadowing, and
quenching on the open prompt charm mesons (D$^0$, D$^+$, D$^{*+}$, D${_s}{^+}$)
production in central Pb + Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV are
investigated within the framework of the {\small HIJING/B\=B v2.0} model. We
compute the nuclear modification factor $R_{\rm PbPb}^{\rm D}$, and show that
the above nuclear effects constitute important dynamical mechanisms in the
description of experimental data. The strength of colour fields (as
characterized by the string tension $\kappa$), partonic energy loss and jet
quenching process lead to a suppression factor consistent with recent published
data. Predictions for future beauty mesons measurements have been included.
Ratios of strange to non-strange prompt charm mesons in central Pb + Pb and
minimum bias (MB) $ p + p$ collisions at 2.76 TeV are also discussed. Minimum
bias $p + p$ collisions which constitute theoretical baseline in our
calculations are studied at the centre of mass energies $\sqrt{s}$ = 2.76 TeV
and 7 TeV.


title: $\propto$SVM for learning with label proportions

abstract:
  We study the problem of learning with label proportions in which the training
data is provided in groups and only the proportion of each class in each group
is known. We propose a new method called proportion-SVM, or $\propto$SVM, which
explicitly models the latent unknown instance labels together with the known
group label proportions in a large-margin framework. Unlike the existing works,
our approach avoids making restrictive assumptions about the data. The
$\propto$SVM model leads to a non-convex integer programming problem. In order
to solve it efficiently, we propose two algorithms: one based on simple
alternating optimization and the other based on a convex relaxation. Extensive
experiments on standard datasets show that $\propto$SVM outperforms the
state-of-the-art, especially for larger group sizes.


title:
Consistent iterated simulation of multi-variate default times: a
  Markovian indicators characterization

abstract:
  We investigate under which conditions a single simulation of joint default
times at a final time horizon can be decomposed into a set of simulations of
joint defaults on subsequent adjacent sub-periods leading to that final
horizon. Besides the theoretical interest, this is also a practical problem as
part of the industry has been working under the misleading assumption that the
two approaches are equivalent for practical purposes. As a reasonable trade-off
between realistic stylized facts, practical demands, and mathematical
tractability, we propose models leading to a Markovian multi-variate
survival--indicator process, and we investigate two instances of static models
for the vector of default times from the statistical literature that fall into
this class. On the one hand, the "looping default" case is known to be equipped
with this property, and we point out that it coincides with the classical
"Freund distribution" in the bivariate case. On the other hand, if all
sub-vectors of the survival indicator process are Markovian, this constitutes a
new characterization of the Marshall--Olkin distribution, and hence of
multi-variate lack-of-memory. A paramount property of the resulting model is
stability of the type of multi-variate distribution with respect to elimination
or insertion of a new marginal component with marginal distribution from the
same family. The practical implications of this "nested margining" property are
enormous. To implement this distribution we present an efficient and unbiased
simulation algorithm based on the L\'evy-frailty construction. We highlight
different pitfalls in the simulation of dependent default times and examine,
within a numerical case study, the effect of inadequate simulation practices.


title:
Large Chern Number Quantum Anomalous Hall Effect In Thin-film
  Topological Crystalline Insulators

abstract:
  Quantum anomalous Hall (QAH) insulators are two-dimensional (2D) insulating
states exhibiting properties similar to those of quantum Hall states but
without external magnetic field. They have quantized Hall conductance
$\sigma^H=Ce^2/h$, where integer $C$ is called the Chern number, and represents
the number of gapless edge modes. Recent experiments demonstrated that chromium
doped thin-film (Bi,Sb)$_2$Te$_3$ is a QAH insulator with Chern number
$C=\pm1$. Here we theoretically predict that thin-film topological crystalline
insulators (TCI) can host various QAH phases, when doped by ferromagnetically
ordered dopants. Any Chern number between $\pm4$ can, in principle, be reached
as a result of the interplay between (a) the induced Zeeman field, depending on
the magnetic doping concentration, (b) the structural distortion, either
intrinsic or induced by a piezoelectric material through proximity effect and
(c) the thickness of the thin film. The tunable Chern numbers found in TCI
possess significant potential for ultra-low power information processing
applications.