title:
Finding Information Through Integrated Ad-Hoc Socializing in the Virtual
  and Physical World

abstract:
  Despite the services of sophisticated search engines like Google, there are a
number of interesting information sources which are useful but largely
inaccessible to current Web users. These information sources are often ad-hoc,
location-specific and only useful for users over short periods of time, or
relate to tacit knowledge of users or implicit knowledge in crowds. The
solution presented in this paper addresses these problems by introducing an
integrated concept of "location" and "presence" across the physical and virtual
worlds enabling ad-hoc socializing of users interested in, or looking for
similar information. While the definition of presence in the physical world is
straightforward - through a spatial location and vicinity at a certain point in
time - their definitions in the virtual world are neither obvious nor trivial.
Based on a detailed analysis we provide an integrated spatial model spanning
both worlds which enables us to define presence of users in a unified way. This
integrated model allows us to enable ad-hoc socializing of users browsing the
Web with users in the physical world specific to their joint information needs
and allows us to unlock the untapped information sources mentioned above. We
describe a proof-of-concept implementation of our model and provide an
empirical analysis based on real-world experiments.


title:
Multiple Scattering of Waves in 3D Crystals (Natural or Photonic) Formed
  by Anisotropically Scattering Centers

abstract:
  This paper considers the refraction and diffraction of waves in
three-dimensional crystals formed by anisotropically scattering centers. The
partial wave expansion method is used to consider the effect of multiple
rescattering of waves by centers composing a crystal. The expression for the
refractive index of a crystal is derived. It is shown that instead of the
diagonal elements of the scattering matrix $\mathbf{T}$, appearing in the
expression for the refractive index of a chaotic medium, the derived expression
includes the diagonal elements of the reaction matrix $\mathbf{K}$. This fact
is taken into account in writing the equations describing the dynamical
diffraction of waves in a crystal.
  The results can be of interest for research into, e.g., diffraction of cold
neutrons and photons in crystals, nanocrystalline materials, as well as for the
description of parametric and diffraction radiation in electromagnetic crystals
formed by anisotropically scattering centers.


title: Cofree Hopf algebras on Hopf bimodule algebras

abstract:
  We investigate a Hopf algebra structure on the cotensor coalgebra associated
to a Hopf bimodule algebra which contains universal version of Clifford
algebras and quantum groups as examples. It is shown to be the bosonization of
the quantum quasi-shuffle algebra built on the space of its right coinvariants.
The universal property and a Rota-Baxter algebra structure are established on
this new algebra.


title: Dark matter from unification

abstract:
  We consider a minimal extension of the Standard Model (SM), which leads to
unification of the SM coupling constants, breaks electroweak symmetry
dynamically by a new strongly coupled sector and leads to novel dark matter
candidates. In this model, the coupling constant unification requires the
existence of electroweak triplet and doublet fermions singlet under QCD and new
strong dynamics underlying the Higgs sector. Among these new matter fields and
a new right handed neutrino, we consider the mass and mixing patterns of the
neutral states. We argue for a symmetry stabilizing the lightest mass
eigenstates of this sector and determine the resulting relic density. The
results are constrained by available data from colliders and direct and
indirect dark matter experiments. We find the model viable and outline briefly
future research directions.


title:
Ellerman Bombs at high resolution: II. Visibility, triggering and effect
  on upper atmosphere

abstract:
  We use high-resolution imaging spectroscopy with the Swedish 1-m Solar
Telescope (SST) to study the transient brightenings of the wings of the Balmer
Halpha line in emerging active regions that are called Ellerman bombs.
Simultaneous sampling of Ca II 854.2 nm with the SST confirms that most
Ellerman bombs occur also in the wings of this line, but with markedly
different morphology. Simultaneous images from the Solar Dynamics Observatory
(SDO) show that Ellerman bombs are also detectable in the photospheric 170 nm
continuum, again with differing morphology. They are also observable in 160 nm
SDO images, but with much contamination from C IV emission in transition-region
features. Simultaneous SST spectropolarimetry in Fe I 630.1 nm shows that
Ellerman bombs occur at sites of strong-field magnetic flux cancelation between
small bipolar strong-field patches that rapidly move together over the solar
surface. Simultaneous SDO images in He II 30.4 nm, Fe IX 17.1 nm, and Fe XIV
21.1 nm show no clear effect of the Ellerman bombs on the overlying transition
region and corona. These results strengthen our earlier suggestion, based on
Halpha morphology alone, that the Ellerman bomb phenomenon is a purely
photospheric reconnection phenomenon.


title: A classification of the face numbers of Buchsbaum simplicial posets

abstract:
  The family of Buchsbaum simplicial posets generalizes the family of
simplicial cell manifolds. The $h'$-vector of a simplicial complex or
simplicial poset encodes the combinatorial and topological data of its face
numbers and the reduced Betti numbers of its geometric realization. Novik and
Swartz showed that the $h'$-vector of a Buchsbaum simplicial poset satisfies
certain simple inequalities; in this paper we show that these necessary
conditions are in fact sufficient to characterize the $h'$-vectors of Buchsbaum
simplicial posets with prescribed Betti numbers.


title:
Effect of the Pauli principle on photoelectron spin transport in $p^+$
  GaAs

abstract:
  In p+ GaAs thin films, the effect of photoelectron degeneracy on spin
transport is investigated theoretically and experimentally by imaging the spin
polarization profile as a function of distance from a tightly-focussed light
excitation spot. Under degeneracy of the electron gas (high concentration, low
temperature), a dip at the center of the polarization profile appears with a
polarization maximum at a distance of about $2 \; \mu m$ from the center. This
counterintuitive result reveals that photoelectron diffusion depends on spin,
as a direct consequence of the Pauli principle. This causes a concentration
dependence of the spin stiffness while the spin dependence of the mobility is
found to be weak in doped material. The various effects which can modify spin
transport in a degenerate electron gas under local laser excitation are
considered. A comparison of the data with a numerical solution of the coupled
diffusion equations reveals that ambipolar coupling with holes increases the
steady-state photo-electron density at the excitation spot and therefore the
amplitude of the degeneracy-induced polarization dip. Thermoelectric currrents
are predicted to depend on spin under degeneracy (spin Soret currents), but
these currents are negligible except at very high excitation power where they
play a relatively small role. Coulomb spin drag and bandgap renormalization are
negligible due to electrostatic screening by the hole gas.


title:
Isospin mixing within the multi-reference nuclear density functional
  theory and beyond - selected aspects

abstract:
  The results of systematic calculations of isospin-symmetry-breaking
corrections to superallowed beta-decays based on the self-consistent isospin-
and angular-momentum-projected nuclear density functional theory (DFT) are
reviewed with an emphasis on theoretical uncertainties of the model. Extensions
of the formalism towards no core shell model approach with basis cutoff scheme
dictated by the self-consistent particle-hole DFT solutions will be also
discussed.


title:
Simple prolongs of the non-positive parts of graded Lie algebras with
  Cartan matrix in characteristic 2

abstract:
  Over an algebraically closed fields, an alternative to the method due to
Kostrikin and Shafarevich was recently suggested. It produces all known simple
finite dimensional Lie algebras in characteristic p>2. For p=2, we investigate
one of the steps of this method, interpret several other simple Lie algebras,
previously known only as sums of their components, as Lie algebras of vector
fields. One new series of exceptional simple Lie algebras is discovered,
together with its "hidden supersymmetries".
  In characteristic 2, certain simple Lie algebras are "desuperizations" of
simple Lie superalgebras. Several simple Lie algebras we describe as results of
generalized Cartan prolongation of the non-positive parts, relative a simplest
(by declaring degree of just one pair of root vectors corresponding to opposite
simple roots nonzero) grading by integers, of Lie algebras with Cartan matrix
are "desuperizations" of characteristic 2 versions of complex simple
exceptional vectorial Lie superalgebras. We list the Lie superalgebras (some of
them new) obtained from the Lie algebras considered by declaring certain
generators odd.
  One of the simple Lie algebras obtained is the prolong relative to a
non-simplest grading, so the classification to be obtained might be more
involved than we previously thought.


title:
Heterogeneity and behavioral response in continuous time
  capture-recapture, with application to street cannabis use in Italy

abstract:
  We propose a general and flexible capture-recapture model in continuous time.
Our model incorporates time-heterogeneity, observed and unobserved individual
heterogeneity, and behavioral response to capture. Behavioral response can
possibly have a delayed onset and a finite-time memory. Estimation of the
population size is based on the conditional likelihood after use of the EM
algorithm. We develop an application to the estimation of the number of adult
cannabinoid users in Italy.


title: An equal-velocity scenario for hiding dark matter at the LHC

abstract:
  We consider a light supersymmetric top quark (stop) scenario, where a stop
and a neutralino are the lightest supersymmetric particles and the stop mass is
close to the sum of the neutralino mass and the top quark mass. In this
scenario, the top quark and the neutralino coming from the decay of a stop have
almost equal velocity vectors, and hence the missing transverse momentum in
stop pair production events at colliders is suppressed, which makes the stop
search challenging, as in the degenerate scenario where the stop mass and the
neutralino mass are nearby. In this paper, we propose a novel analysis
technique aiming at discovering the stop pair production signal in such an
`equal-velocity' scenario. The key is to look for events where the missing
transverse momentum vector is proportional to the transverse momentum vector of
the top quark pair with specific values for the proportionality coefficient, as
this coefficient equals to the ratio of the neutralino mass over the top quark
mass in the equal-velocity limit. We examine the possibility that the stop
signal can be identified at the 14 TeV LHC by our analysis method.


title: U-Duality and the Leech Lattice

abstract:
  It has recently been shown that the full automorphism group of the Leech
lattice, Conway's group Co_0, can be generated by 3 x 3 matrices over the
octonions. We show such matrices are of type F_4 in E_{6(-26)}, the U-duality
group for N=2, D=5 exceptional magic supergravity. By mapping points of the
Leech lattice to black hole charge vectors, it is seen Co_0 is generated by
U-duality transformations acting as rotations in the charge space for BPS black
holes.


title: Highly efficient spin transport in epitaxial graphene on SiC

abstract:
  Spin information processing is a possible new paradigm for post-CMOS
(complementary metal-oxide semiconductor) electronics and efficient spin
propagation over long distances is fundamental to this vision. However, despite
several decades of intense research, a suitable platform is still wanting. We
report here on highly efficient spin transport in two-terminal
polarizer/analyser devices based on high-mobility epitaxial graphene grown on
silicon carbide. Taking advantage of high-impedance injecting/detecting tunnel
junctions, we show spin transport efficiencies up to 75%, spin signals in the
mega-ohm range and spin diffusion lengths exceeding 100 {\mu}m. This enables
spintronics in complex structures: devices and network architectures relying on
spin information processing, well beyond present spintronics applications, can
now be foreseen.


title:
Modified saddle-point integral near singularity for the large deviation
  function

abstract:
  Long-time-integrated quantities in stochastic processes, in or out of
equilibrium, usually exhibit rare but huge fluctuations. Work or heat
production is such a quantity, of which the probability distribution function
displays an exponential decay characterized by the large deviation function
(LDF). The LDF is often deduced from the cumulant generating function through
the inverse Fourier transformation. The saddle-point integration method is a
powerful technique to obtain the asymptotic results in the Fourier integral,
but a special care should be taken when the saddle point is located near a
singularity of the integrand. In this paper, we present a modified saddle-point
method to handle such a difficulty efficiently. We investigate the dissipated
and injected heat production in equilibration processes with various initial
conditions, as an example, where the generating functions contain branch-cut
singularities as well as power-law ones. Exploiting the new modified
saddle-point integrations, we obtain the leading finite-time corrections for
the LDF's, which are confirmed by numerical results.


title: A Quantum Biological Switch Based on Superradiance Transitions

abstract:
  A linear chain of connected electron sites with two asymmetric sinks, one
attached to each end, is used as a simple model of quantum electron transfer in
photosynthetic bio-complexes. For a symmetric initial population in the middle
of the chain, it is expected that electron transfer is mainly directed towards
the strongest coupled sink. However, we show that quantum effects radically
change this intuitive "classical" mechanism, so that electron transfer can
occur through the weaker coupled sink with maximal efficiency. Using this
capability, we show how to design a quantum switch that can transfer an
electron to the left or right branch of the chain, by changing the coupling to
the sinks. The operational principles of this quantum device can be understood
in terms of superradiance transitions and subradiant states. This switching,
being a pure quantum effect, can be used as a witness of wave--like behaviour
of excitations in molecular chains. When realistic data are used for the
photosystem II reaction center, this quantum biological switch is shown to
retain its reliability, even at room temperature.

categories: quant-ph cond-mat.mes-hall cond-mat.stat-mech physics.bio-ph


title: Work extraction and thermodynamics for individual quantum systems

abstract:
  Thermodynamics is traditionally concerned with systems comprised of a large
number of particles. Here we present a framework for extending thermodynamics
to individual quantum systems, including explicitly a thermal bath and
work-storage device (essentially a `weight' that can be raised or lowered). We
prove that the second law of thermodynamics holds in our framework, and give a
simple protocol to extract the optimal amount of work from the system, equal to
its change in free energy. Our results apply to any quantum system in an
arbitrary initial state, in particular including non-equilibrium situations.
The optimal protocol is essentially reversible, similar to classical Carnot
cycles, and indeed, we show that it can be used it to construct a quantum
Carnot engine.


title: JIMWLK evolution for multi-particle production in Langevin form

abstract:
  Within the effective theory for the Color Glass Condensate, we study
multi-particle production with rapidity correlations in proton-nucleus
collisions at high energy. The high-energy evolution responsible for such
correlations is governed by a generalization of the JIMWLK equation which
describes the simultaneous evolution of the (strong) nuclear color fields in
the direct amplitude and the complex conjugate amplitude. This functional
equation can be used to derive ordinary evolution equations for the
cross-sections for particle production (a generalization of the Balitsky
hierarchy). However, the ensuing equations appear to be too complicated to be
useful in practice, including in the limit where the number of colors is large.
To circumvent this problem, we propose an alternative formulation of the
high-energy evolution as a Langevin process, which is better suited for
numerical implementations. This process is directly oriented towards the
calculation of the cross-sections, so its detailed structure depends upon the
nature of the final state. We present the stochastic equations appropriate for
two gluon production, and also for three gluon production, with generic
rapidity differences.


title: Compressed Pattern-Matching with Ranked Variables in Zimin Words

abstract:
  Zimin words are very special finite words which are closely related to the
pattern-avoidability problem. This problem consists in testing if an instance
of a given pattern with variables occurs in almost all words over any finite
alphabet. The problem is not well understood, no polynomial time algorithm is
known and its NP-hardness is also not known. The pattern-avoidability problem
is equivalent to searching for a pattern (with variables) in a Zimin word. The
main difficulty is potentially exponential size of Zimin words. We use special
properties of Zimin words, especially that they are highly compressible, to
design efficient algorithms for special version of the pattern-matching, called
here ranked matching. It gives a new interpretation of Zimin algorithm in
compressed setting. We discuss the structure of rankings of variables and
compressed representations of values of variables. Moreover, for a ranked
matching we present efficient algorithms to find the shortest instance and the
number of valuations of instances of the pattern.


title:
A Sub-block Based Image Retrieval Using Modified Integrated Region
  Matching

abstract:
  This paper proposes a content based image retrieval (CBIR) system using the
local colour and texture features of selected image sub-blocks and global
colour and shape features of the image. The image sub-blocks are roughly
identified by segmenting the image into partitions of different configuration,
finding the edge density in each partition using edge thresholding followed by
morphological dilation. The colour and texture features of the identified
regions are computed from the histograms of the quantized HSV colour space and
Gray Level Co- occurrence Matrix (GLCM) respectively. The colour and texture
feature vectors is computed for each region. The shape features are computed
from the Edge Histogram Descriptor (EHD). A modified Integrated Region Matching
(IRM) algorithm is used for finding the minimum distance between the sub-blocks
of the query and target image. Experimental results show that the proposed
method provides better retrieving result than retrieval using some of the
existing methods.


title: Nowhere-zero flows on signed regular graphs

abstract:
  We study the flow spectrum ${\cal S}(G)$ and the integer flow spectrum
$\overline{{\cal S}}(G)$ of signed $(2t+1)$-regular graphs. We show that if $r
\in {\cal S}(G)$, then $r = 2+\frac{1}{t}$ or $r \geq 2 + \frac{2}{2t-1}$.
Furthermore, $2 + \frac{1}{t} \in {\cal S}(G)$ if and only if $G$ has a
$t$-factor. If $G$ has a 1-factor, then $3 \in \overline{{\cal S}}(G)$, and for
every $t \geq 2$, there is a signed $(2t+1)$-regular graph $(H,\sigma)$ with $
3 \in \overline{{\cal S}}(H)$ and $H$ does not have a 1-factor.
  If $G$ $(\not = K_2^3)$ is a cubic graph which has a 1-factor, then $\{3,4\}
\subseteq {\cal S}(G) \cap \overline{{\cal S}}(G)$. Furthermore, the following
four statements are equivalent: (1) $G$ has a 1-factor. (2) $3 \in {\cal
S}(G)$. (3) $3 \in \overline{{\cal S}}(G)$. (4) $4 \in \overline{{\cal S}}(G)$.
There are cubic graphs whose integer flow spectrum does not contain 5 or 6, and
we construct an infinite family of bridgeless cubic graphs with integer flow
spectrum $\{3,4,6\}$.
  We show that there are signed graphs where the difference between the integer
flow number and the flow number is greater than or equal to 1, disproving a
conjecture of Raspaud and Zhu.
  The paper concludes with a proof of Bouchet's 6-flow conjecture for
Kotzig-graphs.


title:
Scrape-off layer ion temperature measurements at the divertor target in
  MAST by retarding field energy analyser

abstract:
  Knowledge of the ion temperature (Ti) is of key importance for determining
heat fluxes to the divertor and plasma facing components, however data
regarding this is limited compared to electron temperature (Te) data. Ti
measurements at the divertor target, between edge-localised modes (inter-ELM)
H-mode, have been made using a novel retarding field energy analyser (RFEA).


title:
Acceleration of solar wind ions to 1 MeV by electromagnetic structures
  upstream of the Earth's bow shock

abstract:
  We present measurements from the ESA/NASA Cluster mission that show in situ
acceleration of ions to energies of 1 MeV outside the bow shock. The observed
heating can be associated with the presence of electromagnetic structures with
strong spatial gradients of the electric field that lead to ion gyro-phase
breaking and to the onset of chaos in ion trajectories. It results in rapid,
stochastic acceleration of ions in the direction perpendicular to the ambient
magnetic field. The electric potential of the structures can be compared to a
field of moguls on a ski slope, capable of accelerating and ejecting the fast
running skiers out of piste. This mechanism may represent the universal
mechanism for perpendicular acceleration and heating of ions in the
magnetosphere, the solar corona and in astrophysical plasmas. This is also a
basic mechanism that can limit steepening of nonlinear electromagnetic
structures at shocks and foreshocks in collisionless plasmas.


title: Concentration inequalities for smooth random fields

abstract:
  In this note we derive a sharp concentration inequality for the supremum of a
smooth random field over a finite dimensional set. It is shown that this
supremum can be bounded with high probability by the value of the field at some
deterministic point plus an intrinsic dimension of the optimisation problem. As
an application we prove the exponential inequality for a function of the
maximal eigenvalue of a random matrix is proved.


title:
Core-crust transition pressure for relativistic slowly rotating neutron
  stars

abstract:
  We study the influence of core-\textit{crust} transition pressure changes on
the general dynamical properties of neutron star configurations. First we study
the matching conditions in core-\textit{crust} transition pressure region,
where phase transitions in the equation of state causes energy density jumps.
Then using a surface \textit{crust} approximation, we can construct
configurations where the matter is described by the equation of state of the
core of the star and the core-\textit{crust} transition pressure. We will
consider neutron stars in the slow rotation limit, considering perturbation
theory up to second order in the angular velocity so that the deformation of
the star is also taken into account. The junction determines the parameters of
the star such as total mass, angular and quadrupolar momentum.


title: On the coset category of a skew lattice

abstract:
  Skew lattices are non-commutative generalizations of lattices. The coset
structure decomposition is an original approach to the study of these algebras
describing the relation between its rectangular classes. In this paper we will
look at the category determined by these rectangular algebras and the morphisms
between them, showing that not all skew lattices can determine such a category.
Furthermore, we will present a class of examples of skew lattices in rings that
are not strictly categorical, and present sufficient conditions for skew
lattices of matrices in rings to constitute $\wedge$-distributive skew
lattices.


title:
Using MathML to Represent Units of Measurement for Improved Ontology
  Alignment

abstract:
  Ontologies provide a formal description of concepts and their relationships
in a knowledge domain. The goal of ontology alignment is to identify
semantically matching concepts and relationships across independently developed
ontologies that purport to describe the same knowledge. In order to handle the
widest possible class of ontologies, many alignment algorithms rely on
terminological and structural meth- ods, but the often fuzzy nature of concepts
complicates the matching process. However, one area that should provide clear
matching solutions due to its mathematical nature, is units of measurement.
Several on- tologies for units of measurement are available, but there has been
no attempt to align them, notwithstanding the obvious importance for tech-
nical interoperability. We propose a general strategy to map these (and
similar) ontologies by introducing MathML to accurately capture the semantic
description of concepts specified therein. We provide mapping results for three
ontologies, and show that our approach improves on lexical comparisons.


title: Entanglement improves classical control

abstract:
  Electronic devices all around us contain classical control circuits. Such
circuits consist of a network of controllers which can read and write signals
to wires of the circuit with the goal to minimize the cost function of the
circuit's output signal. Here, we propose the use of shared entanglement
between controllers as a resource to improve the performance of otherwise
purely classical control circuits. We study a well-known example from the
classical control literature and demonstrate that allowing two controllers to
share entanglement improves their ability to control. More precisely, we
exhibit a family of circuits in which the the cost function using entanglement
stays constant, but the minimal cost function without entanglement grows
arbitrarily large. This demonstrates that entanglement can be a powerful
resource in a classical control circuit.


title: Axial Quasi-normal modes of Neutron Stars with Exotic Matter

abstract:
  We investigate the axial w quasi-normal modes of neutron stars for 18
realistic equations of state in order to study the influence of hyperons and
quarks on the modes. The study has been developed with a new method based on
Exterior Complex Scaling with variable angle, which allow us to generate pure
outgoing quasi-normal modes. A complete study of the junction conditions has
been done. We have obtained that w-modes can be used to distinguish between
neutron stars with exotic matter and without exotic matter for compact enough
stars.


title:
Electron Sources for Future Lightsources, Summary and Conclusions for
  the Activities during FLS 2012

abstract:
  This paper summarizes the discussions, presentations, and activity of the
Future Light Sources Workshop 2012 (FLS 2012) working group dedicated to
Electron Sources. The focus of the working group was to discuss concepts and
technologies that might enable much higher peak and average brightness from
electron beam sources. Furthermore the working group was asked to consider
methods to greatly improve the robustness of operation and lower the costs of
providing electrons.


title:
Existence of solutions for a mathematical model related to solid-solid
  phase transitions in shape memory alloys

abstract:
  We consider a strongly nonlinear PDE system describing solid-solid phase
transitions in shape memory alloys. The system accounts for the evolution of an
order parameter (related to different symmetries of the crystal lattice in the
phase configurations), of the stress (and the displacement), and of the
absolute temperature. The resulting equations present several technical
difficulties to be tackled: in particular, we emphasize the presence of
nonlinear coupling terms, higher order dissipative contributions, possibly
multivalued operators. As for the evolution of temperature, a highly nonlinear
parabolic equation has to be solved for a right hand side that is controlled
only in L^1. We prove the existence of a solution for a regularized version, by
use of a time discretization technique. Then, we perform suitable a priori
estimates which allow us pass to the limit and find a weak global-in-time
solution to the system.


title:
Characteristics of X-point Lobe Structures in Single-Null Discharges on
  MAST

abstract:
  Lobe structures due to the application of resonant magnetic perturbations
(RMPs) have been observed using wide-angle imaging of light from He1+ ions in
the vicinity of the lower X-point in MAST. The data presented are from lower
single-null discharges where RMPs of toroidal mode number, n, of 4 and 6 were
applied. It has been found that, above a threshold value, the lobe structures
extend radially, linearly with the coil current, both in L-mode and H-mode. It
is observed that after the application of the RMP, as the toroidal rotation in
the confined plasma decreases, the lobes extend radially, suggesting the plasma
is less effectively screening the RMP field. Comparing the imaging data with
results from vacuum modelling shows that this technique can accurately predict
the number and poloidal location of the lobes, but over-estimates their radial
extent. More accurate estimates of the extent of the lobes can be made by
accounting for plasma screening of the RMP field. Qualitative agreement between
simulation and experiment is found if it is assumed that the RMP penetrates 2%
in normalised radius from the last closed flux surface.


title:
Central Limit Theorems and Large Deviations for Additive Functionals of
  Reflecting Diffusion Processes

abstract:
  This paper develops central limit theorems (CLT's) and large deviations
results for additive functionals associated with reflecting diffusions in which
the functional may include a term associated with the cumulative amount of
boundary reflection that has occurred. Extending the known central limit and
large deviations theory for Markov processes to include additive functionals
that incorporate boundary reflection is important in many applications settings
in which reflecting diffusions arise, including queueing theory and economics.
In particular, the paper establishes the partial differential equations that
must be solved in order to explicitly compute the mean and variance for the
CLT, as well as the associated rate function for the large deviations
principle.


title: Non-Abrikosov vortices in liquid metallic hydrogen

abstract:
  We consider non-Abrikosov vortex solutions in liquid metallic hydrogen (LMH)
in the framework of two-component Ginzburg-Landau model. We have shown that
there are three types of non-Abrikosov vortices depending on chosen boundary
conditions at the core of vortices, namely, Neumann (N)-type, Dirichlet
(D)-type and Gross-Pitaevskii (GP)-type vortices. The Neumann-type vortex has a
non-vanishing condensation at the core, that is different from the ordinary
vortex, and the magnetic flux could be reversed as well in LMH. Furthermore, we
have obtained a new type of a neutral vortex which has no magnetic field. The
presence of such a vortex is related to metallic superfluid state suggested by
Babaev.


title:
Instabilities of rotational flows in azimuthal magnetic fields of
  arbitrary radial dependence

abstract:
  Using the WKB approximation we perform a linear stability analysis for a
rotational flow of a viscous and electrically conducting fluid in an external
azimuthal magnetic field that has an arbitrary radial profile B_{phi}(R). In
the inductionless approximation, we find the growth rate of the
three-dimensional perturbation in a closed form and demonstrate in particular
that it can be positive when the velocity profile is Keplerian and the magnetic
field profile is slightly shallower than R^{-1}.

categories: astro-ph.SR math.DS physics.flu-dyn physics.plasm-ph


title: On the Theorem of the Three Perpendiculars

abstract:
  We show that the theorem of the three perpendiculars holds in any
n-dimensional space form.


title: Various stabilities of the Alexander polynomials of knots and links

abstract:
  In this paper, we study distribution of the zeros of the Alexander
polynomials of knots and links in S^3. We call a knot or link "real stable"
(resp. "circular stable") if all the zeros of its Alexander polynomial are real
(resp. unit complex). We give a general construction of real stable and
circular stable knots and links. We also study pairs of real stable knots and
links such that the zeros of the Alexander polynomials are interlaced.


title:
A new method of waveform digitization based on time-interleaved A/D
  conversion

abstract:
  Time interleaved analog-to-digital conversion (TIADC) based on parallelism is
an effective way to meet the requirement of the ultra-fast waveform digitizer
beyond Gsps. Different methods to correct the mismatch errors among different
analog-to-digital conversion channels have been developed previously. To
overcome the speed limitation in hardware design and to implement the mismatch
correction algorithm in real time, this paper proposes a fully parallel
correction algorithm. A 12-bit 1-Gsps waveform digitizer with ENOB around 10.5
bit from 5 MHz to 200 MHz is implemented based on the real-time correction
algorithm.


title: Search for Impact Craters in Iran: Citizen Science as a Useful Method

abstract:
  To recognition probable impact craters in Iran, we use Google Earth data in
the first step. Some probable structures identified and studies suggest
non-impact origin for them. Studies on other craters in Iran are in progress.


title: Optimal placement of Marine Protected Areas

abstract:
  Overfishing can lead to the reduction or elimination of fish populations and
the degradation or even destruction of their habitats. This can be prevented by
introducing Marine Protected Areas (MPA's), regions in the ocean or along
coastlines where fishing is controlled. MPA's can also lead to larger fish
densities outside the protected area through spill-over, which in turn may
increase the fishing yield. A natural question in this context, is where
exactly to establish an MPA, in order to maximize these benefits. This problem
is addressed along a one-dimensional stretch of coast-line, by first proposing
a model for the fish dynamics. Fish are assumed to move diffusively, and are
subject to recruitment, natural death and harvesting through fishing. The
problem is then cast as an optimal control problem for the steady state
equation corresponding to the PDE which models the fish dynamics. The
functional being maximized is a weighted sum of the average fish density and
the average fishing yield. It is shown that optimal controls exist, and that
the form of an optimal control -and hence the location of the MPA- is
determined by two key model parameters, namely the size of the coast, and the
weight of the average fish density appearing in the functional. If these
parameters are large enough -and precisely how large, can be calculated
exactly- the results indicate when and where an MPA should be established. The
results indicate that an MPA always takes the form of a Marine Reserve, where
fishing is prohibited. The main mathematical tool used to prove the results is
Pontryagin's maximum principle.


title:
Chi-square goodness of fit tests for weighted histograms. Review and
  improvements

abstract:
  Weighted histograms are used for the estimation of probability density
functions. Computer simulation is the main domain of application of this type
of histogram. A review of chi-square goodness of fit tests for weighted
histograms is presented in this paper. Improvements are proposed to these tests
that have size more close to its nominal value. Numerical examples are
presented in this paper for evaluation of tests and to demonstrate various
applications of tests.

categories: physics.data-an astro-ph.IM hep-ex nucl-ex stat.AP


title:
The network of stabilizing contacts in proteins studied by
  coevolutionary data

abstract:
  The primary structure of proteins, that is their sequence, represents one of
the most abundant set of experimental data concerning biomolecules. The study
of correlations in families of co--evolving proteins by means of an inverse
Ising--model approach allows to obtain information on their native
conformation. Following up on a recent development along this line, we optimize
the algorithm to calculate effective energies between the residues, validating
the approach both back-calculating interaction energies in a model system, and
predicting the free energies associated to mutations in real systems. Making
use of these effective energies, we study the networks of interactions which
stabilizes the native conformation of some well--studied proteins, showing that
it display different properties than the associated contact network.


title:
Comparing Data-mining Algorithms Developed for Longitudinal
  Observational Databases

abstract:
  Longitudinal observational databases have become a recent interest in the
post marketing drug surveillance community due to their ability of presenting a
new perspective for detecting negative side effects. Algorithms mining
longitudinal observation databases are not restricted by many of the
limitations associated with the more conventional methods that have been
developed for spontaneous reporting system databases. In this paper we
investigate the robustness of four recently developed algorithms that mine
longitudinal observational databases by applying them to The Health Improvement
Network (THIN) for six drugs with well document known negative side effects.
Our results show that none of the existing algorithms was able to consistently
identify known adverse drug reactions above events related to the cause of the
drug and no algorithm was superior.


title: Drift-induced perpendicular transport of Solar Energetic Particles

abstract:
  Drifts are known to play a role in galactic cosmic ray transport within the
heliosphere and are a standard component of cosmic ray propagation models.
However, the current paradigm of Solar Energetic Particle (SEP) propagation
holds the effects of drifts to be negligible, and they are not accounted for in
most current SEP modelling efforts. We present full-orbit test particle
simulations of SEP propagation in a Parker spiral interplanetary magnetic field
which demonstrate that high energy particle drifts cause significant asymmetric
propagation perpendicular to the interplanetary magnetic field. Thus in many
cases the assumption of field aligned propagation of SEPs may not be valid. We
show that SEP drifts have dependencies on energy, heliographic latitude, and
charge to mass ratio, that are capable of transporting energetic particles
perpendicular to the field over significant distances within interplanetary
space, e.g. protons of initial energy 100 MeV propagate distances across the
field on the order of 1 AU, over timescales typical of a gradual SEP event. Our
results demonstrate the need for current models of SEP events to include the
effects of particle drift. We show that the drift is considerably stronger for
heavy ion SEPs due to their larger mass to charge ratio. This paradigm shift
has important consequences for the modelling of SEP events and is crucial to
the understanding and interpretation of in-situ observations.


title:
Evaluating strategies of phylogenetic analyses by the coherence of their
  results

abstract:
  I propose an approach to identify, among several strategies of phylogenetic
analysis, those producing the most accurate results. This approach is based on
the hypothesis that the more a result is reproduced from independent data, the
more it reflects the historical signal common to the analysed data. Under this
hypothesis, the capacity of an analytical strategy to extract historical signal
should correlate positively with the coherence of the obtained results. I apply
this approach to a series of analyses on empirical data, basing the coherence
measure on the Robinson-Foulds distances between the obtained trees. At first
approximation, the analytical strategies most suitable for the data produce the
most coherent results. However, risks of false positives and false negatives
are identified, which are difficult to rule out.


title:
Determination of hydrogen cluster velocities and comparison with
  numerical calculations

abstract:
  The use of powerful hydrogen cluster jet targets in storage ring experiments
led to the need of precise data on the mean cluster velocity as function of the
stagnation temperature and pressure for the determination of the volume density
of the target beams. For this purpose a large data set of hydrogen cluster
velocity distributions and mean velocities was measured at a high density
hydrogen cluster jet target using a trumpet shaped nozzle. The measurements
have been performed at pressures above and below the critical pressure and for
a broad range of temperatures relevant for target operation, e.g., at storage
ring experiments. The used experimental method is described which allows for
the velocity measurement of single clusters using a time-of-flight technique.
Since this method is rather time-consuming and these measurements are typically
interfering negatively with storage ring experiments, a method for a precise
calculation of these mean velocities was needed. For this, the determined mean
cluster velocities are compared with model calculations based on an isentropic
one-dimensional van der Waals gas. Based on the obtained data and the presented
numerical calculations, a new method has been developed which allows to predict
the mean cluster velocities with an accuracy of about 5%. For this two cut-off
parameters defining positions inside the nozzle are introduced, which can be
determined for a given nozzle by only two velocity measurements.


title: Symmetric functions of two noncommuting variables

abstract:
  We prove a noncommutative analogue of the fact that every symmetric analytic
function of $(z,w)$ in the bidisc $\D^2$ can be expressed as an analytic
function of the variables $z+w$ and $zw$. We construct an analytic nc-map $S$
from the biball to an infinite-dimensional nc-domain $\Omega$ with the property
that, for every bounded symmetric function $\ph$ of two noncommuting variables
that is analytic on the biball, there exists a bounded analytic nc-function
$\Phi$ on $\Omega$ such that $\ph=\Phi\circ S$. We also establish a realization
formula for $\Phi$, and hence for $\ph$, in terms of operators on Hilbert
space.


title: A counterexample to a question of Hof, Knill and Simon

abstract:
  In this article, we give a negative answer to a question of Hof, Knill and
Simon (1995) concerning purely morphic sequences obtained from primitive
morphism containing an infinite number of palindromes. Proven for the binary
alphabet by B. Tan in 2007, we show the existence of a counterexample on the
ternary alphabet.


title: Conservation laws in theories with universal gravity/matter coupling

abstract:
  In this paper, we investigate the conservation laws of different type of
particles in theories with a universal gravity/matter coupling. The result
brings new insights about previous studies on universal gravity/matter
theories. Especially, the paper demonstrates that for perfect fluids, there is
an equivalence between the assumption $\L_m=-\epsilon$, where $\epsilon$ is the
total energy density; and the assumption that the matter fluid current is
conserved ($\nabla_\sigma (\rho u^\sigma)=0$, where $\rho$ is the rest mass
density). However, the main result is given in the general case where one does
not make any assumption on the conservation of the matter fluid current.


title: X-ray observations of the Compton-thick Seyfert 2 galaxy, NGC 5643

abstract:
  We present results from a ~55 ks long XMM-Newton observation of the obscured
AGN, NGC 5643, performed in July 2009. A previous, shorter (about 10 ks)
XMM-Newton observation in February 2003 had left two major issues open, the
nature of the hard X-ray emission (Compton-thin vs Compton-thick) and of the
soft X-ray excess (photoionized vs collisionally ionized matter). The new
observation shows that the source is Compton-thick and that the dominant
contribution to the soft X-ray emission is by photoionized matter (even if it
is still unclear whether collisionally ionized matter may contribute as well).
  We also studied three bright X-ray sources that are in the field of NGC 5643.
The ULX NGC 5643 X-1 was confirmed to be very luminous, even if more than a
factor 2 fainter than in 2003. We then provided the first high quality spectrum
of the cluster of galaxies Abell 3602. The last source, CXOJ143244.5-442020, is
likely an unobscured AGN, possibly belonging to Abell 3602.


title:
Deep Luminosity Functions and Colour-Magnitude Relations for Cluster
  Galaxies at 0.2 < z < 0.6

abstract:
  We derive deep $I$ band luminosity functions and colour-magnitude diagrams
from HST imaging for eleven $0.2<z<0.6$ clusters observed at various stages of
merging, and a comparison sample of five more relaxed clusters at similar
redshifts. The characteristic magnitude $M^*$ evolves passively out to $z=0.6$,
while the faint end slope of the luminosity function is $\alpha \sim -1$ at all
redshifts. Cluster galaxies must have been completely assembled down to $M_I
\sim -18$ out to $z=0.6$. We observe tight colour-magnitude relations over a
luminosity range of up to 8 magnitudes, consistent with the passive evolution
of ancient stellar populations. This is found in all clusters, irrespective of
their dynamical status (involved in a collision or not, or even within
subclusters for the same object) and suggests that environment does not have a
strong influence on galaxy properties. A red sequence luminosity function can
be followed to the limits of our photometry: we see no evidence of a weakening
of the red sequence to $z=0.6$. The blue galaxy fraction rises with redshift,
especially at fainter absolute magnitudes. We observe bright blue galaxies in
clusters at $z > 0.4$ that are not encountered locally. Surface brightness
selection effects preferentially influence the detectability of faint red
galaxies, accounting for claims of evolution at the faint end.


title: Accretion and Outflow Activity in Brown Dwarfs

abstract:
  An investigation of the magnetospheric accretion and outflow signatures in
sub-stellar objects is a natural extension of similar studies conducted on
classical T Tauri stars (CTTS), and helps understand if brown dwarfs (BDs)
follow the same formation mechanism as stars. Over the past decade, evidence
for accretion in very low-mass stars (VLMs) and BDs has been accumulated using
various techniques, which indicates that the overall accretion characteristics
are continuous across the sub-stellar boundary. Outflow activity in VLMs and
BDs has been confirmed based on spectro-astrometry of forbidden emission lines
observed in the optical, and in millimetre continuum images of CO J=2-1
emission. This review summarizes the past and current state of observational
work on accretion and outflow activity in VLMs and BDs, particularly with the
advent of new instruments such as VLT/X-Shooter which has allowed the study of
several accretion and outflow indicators over a wider wavelength range.


title:
X-ray emission around the z=4.1 radio galaxy TNJ1338-1942 and the
  potential role of far-infrared photons in AGN Feedback

abstract:
  We report the discovery in an 80-ks observation of spatially-extended X-ray
emission around the high-redshift radio galaxy TNJ1388-1942 (z=4.11) with the
Chandra X-ray Observatory. The X-ray emission extends over a ~30-kpc diameter
region and although it is less extended than the GHz-radio lobes, it is roughly
aligned with them. We suggest that the X-ray emission arises from Inverse
Compton (IC) scattering of photons by relativistic electrons around the radio
galaxy. At z=4.11 this is the highest redshift detection of IC emission around
a radio galaxy. We investigate the hypothesis that in this compact source, the
Cosmic Microwave Background (CMB), which is ~700x more intense than at z~0 is
nonetheless not the relevant seed photon field for the bulk of the IC emission.
Instead, we find a tentative correlation between the IC emission and
far-infrared luminosities of compact, far-infrared luminous high-redshift radio
galaxies (those with lobe lengths of <100kpc). Based on these results we
suggest that in the earliest phases of the evolution of radio-loud AGN at very
high redshift, the far-infrared photons from the co-eval dusty starbursts
occuring within these systems may make a significant contribution to their IC
X-ray emission and so contribute to the feedback in these massive high-redshift
galaxies.


title:
The dynamical status of ZwCl 2341.1+0000: a very elongated galaxy
  structure with a complex radio emission

abstract:
  We study the dynamical status of the galaxy system ZwCl 2341.1+0000, a
filamentary multi-Mpc galaxy structure associated with a complex diffuse radio
emission. Our analysis is mainly based on new spectroscopic data for 128
galaxies acquired at the TNG telescope. We also use optical data available in
the SDSS and X-ray data from the Chandra archive. We select 101 cluster member
galaxies and compute the cluster redshift <z>~0.2693 and the global LOS
velocity dispersion ~1000 km/s. Our optical analysis agrees with the presence
of at least three, likely four or more, optical subclusters causing the SSE-NNW
elongation of the galaxy distribution and a significant velocity gradient in
the S-N direction. In particular, we detect an important low-velocity subclump
in the southern region, roughly coincident with the brightest peak of the
diffuse radio emission but with a clear offset between the optical and radio
peaks. We also detect one (or two) optical subcluster(s) at north, in
correspondence with the second brightest radio emission, and another one in the
central cluster region, where a third diffuse radio source has been recently
detected. A more refined analysis involving the study of the 2D galaxy
distribution suggests an even more complex structure. As for the X-ray
analysis, we confirm the SSE-NNW elongation of the intracluster medium and
detect four significant peaks. The X-ray emission is strongly asymmetric and
offsetted with respect to the galaxy distribution, thus suggesting a merger
caught in the phase of post-core-core passage. Our findings support two
possible hypotheses for the nature of the diffuse radio emission of ZwCl
2341.1+0000: a 2 relics+halo scenario or diffuse emission associated with the
infall and merging of several galaxy groups during the first phase of the
cluster formation.


title: The Stochastic Field Transport associated with the Slab ITG Modes

abstract:
  Many models for anomalous transport consider the turbulent ExB transport
arising from electrostatic micro-instabilities. In this paper we investigate
whether the perturbed magnetic field that is associated with such instabilities
at small but finite values of {beta} can lead to significant stochastic
magnetic field transport. Using the tearing parity, long wave-length ion
temperature gradient (ITG) modes in a plasma slab with magnetic shear as an
example, we calculate the amplitude of the perturbed magnetic field that
results at the resonant surface for the case when the plasma dissipation is
given by the semi-collisional electron model. The resulting stochastic field
transport is estimated and also compared with an estimate for the ExB transport
due to the ITG mode.


title: A Beginners Guide to Systems Simulation in Immunology

abstract:
  Some common systems modelling and simulation approaches for immune problems
are Monte Carlo simulations, system dynamics, discrete-event simulation and
agent-based simulation. These methods, however, are still not widely adopted in
immunology research. In addition, to our knowledge, there is few research on
the processes for the development of simulation models for the immune system.
Hence, for this work, we have two contributions to knowledge. The first one is
to show the importance of systems simulation to help immunological research and
to draw the attention of simulation developers to this research field. The
second contribution is the introduction of a quick guide containing the main
steps for modelling and simulation in immunology, together with challenges that
occur during the model development. Further, this paper introduces an example
of a simulation problem, where we test our guidelines.


title: Extending a Microsimulation of the Port of Dover

abstract:
  Modelling and simulating the traffic of heavily used but secure environments
such as seaports and airports is of increasing importance. This paper discusses
issues and problems that may arise when extending an existing microsimulation
strategy. We also discuss how extensions of these simulations can aid planners
with optimal physical and operational feedback. Conclusions are drawn about how
microsimulations can be moved forward as a robust planning tool for the 21st
century.


title:
Supervised Learning and Anti-learning of Colorectal Cancer Classes and
  Survival Rates from Cellular Biology Parameters

abstract:
  In this paper, we describe a dataset relating to cellular and physical
conditions of patients who are operated upon to remove colorectal tumours. This
data provides a unique insight into immunological status at the point of tumour
removal, tumour classification and post-operative survival. Attempts are made
to learn relationships between attributes (physical and immunological) and the
resulting tumour stage and survival. Results for conventional machine learning
approaches can be considered poor, especially for predicting tumour stages for
the most important types of cancer. This poor performance is further
investigated and compared with a synthetic, dataset based on the logical
exclusive-OR function and it is shown that there is a significant level of
'anti-learning' present in all supervised methods used and this can be
explained by the highly dimensional, complex and sparsely representative
dataset. For predicting the stage of cancer from the immunological attributes,
anti-learning approaches outperform a range of popular algorithms.


title: On the Strichartz estimates for the kinetic transport equation

abstract:
  We show that the endpoint Strichartz estimate for the kinetic transport
equation is false in all dimensions. We also present a new approach to proving
the non-endpoint cases using multilinear analysis.


title:
Biomarker Clustering of Colorectal Cancer Data to Complement Clinical
  Classification

abstract:
  In this paper, we describe a dataset relating to cellular and physical
conditions of patients who are operated upon to remove colorectal tumours. This
data provides a unique insight into immunological status at the point of tumour
removal, tumour classification and post-operative survival. Attempts are made
to cluster this dataset and important subsets of it in an effort to
characterize the data and validate existing standards for tumour
classification. It is apparent from optimal clustering that existing tumour
classification is largely unrelated to immunological factors within a patient
and that there may be scope for re-evaluating treatment options and survival
estimates based on a combination of tumour physiology and patient
histochemistry.


title:
Effect of magnetic fields on equatorial circular orbits in Kerr
  spacetimes

abstract:
  In this work we analyze the effects of an external magnetic field on charged
particles on equatorial circular orbits in a Kerr spacetime, both in the black
hole and the naked singularity cases. Understanding these phenomena is of great
importance because equatorial circular orbits are a key ingredient of simple
accretion disc models. We focus on two important magnetic field configurations:
a) a uniform magnetic field aligned with the angular momentum and b) a dipolar
magnetic field. We center our attention on the effect of these external fields
on the marginally bounded and marginally stable equatorial circular orbits
because they give information on observable quantities that could be useful to
determine whether the central object is a black hole or a naked singularity.
Using a perturbative approach we are able to give analytic results and compare
(in the black hole case) with previous results.


title: Bondi mass cannot become negative in higher dimensions

abstract:
  We prove that the Bondi mass of an asymptotically flat, vacuum, spacetime
cannot become negative in any even dimension $d \ge 4$. The notion of Bondi
mass is more subtle in $d > 4$ dimensions because radiating metrics have a
slower decay than stationary ones, and those subtleties are reflected by a
considerably more difficult proof of positivity. Our proof holds for the
standard spherical infinities, but also extends to infinities of more general
type which are $(d-2)$-dimensional manifolds admitting a real Killing spinor.
Such manifolds typically have special holonomy and Sasakian structures. The
main technical advance of the paper is an expansion technique based on
"conformal Gaussian null coordinates". This expansion helps us to understand
the consequences imposed by Einstein's equations on the asymptotic tail of the
metric field. As a by-product, we derive a coordinate expression for the
geometrically invariant formula for the Bondi mass originally given by Hollands
and Ishibashi.


title: Can a wormhole be interpreted as an EPR pair?

abstract:
  Recently, Maldacena and Susskind arXiv:1306.0533 and Jensen and Karch
arXiv:1307.1132 argued that a wormhole can be interpreted as an EPR pair. We
point out that a convincing justification of such an interpretation would
require a quantitative evidence that correlations between two ends of the
wormhole are equal to those between the members of the EPR pair. As long as the
existing results do not contain such evidence, the interpretation of wormhole
as an EPR pair does not seem justified.


title:
Two-dimensional ternary locally resonant phononic crystals with a
  comblike coating

abstract:
  Two-dimensional ternary locally resonant phononic crystals used to consist of
cylindrical scatterers with uniform coatings in their exterior. An alternative
coating scheme with a comblike profile is proposed and investigated in this
letter. The band structures are calculated by using the finite element method.
It is found that a complete bandgap at a significantly low frequency can be
induced. The mechanism for such a change is suggested by using an equivalent
spring-mass model based on analyzing the eigen modes at the bandgap edges.
Consistent results are obtained from the numerical results and the analysis of
the spring-mass model.


title:
Symmetric Reduction and Hamilton-Jacobi Equation of Rigid Spacecraft
  with a Rotor

abstract:
  In this paper, we consider the rigid spacecraft with an internal rotor as a
regular point reducible regular controlled Hamiltonian (RCH) system. In the
cases of coincident and non-coincident centers of buoyancy and gravity, we give
explicitly the motion equation and Hamilton-Jacobi equation of reduced
spacecraft-rotor system on a symplectic leaf by calculation in detail,
respectively, which show the effect on controls in regular symplectic reduction
and Hamilton-Jacobi theory.


title:
Spin-orbit coupled fermions in ladder-like optical lattices at
  half-filling

abstract:
  We study the ground-state phase diagram of two-component fermions loaded in a
ladder-like lattice at half filling in the presence of spin-orbit coupling. For
repulsive fermions with unidirectional spin-orbit coupling along the legs we
identify a N\'{e}el state which is separated from rung-singlet and
ferromagnetic states by Ising phase transition lines. These lines cross for
maximal spin-orbit coupling and a direct Gaussian phase transition between
rung-singlet and ferro phases is realized. For the case of Rashba-like
spin-orbit coupling, besides the rung singlet phases two distinct striped
ferromagnetic phases are formed. In case of attractive fermions with spin-orbit
coupling at half-filling for decoupled chains we identify a dimerized state
that separates a singlet superconductor and a ferromagnetic states.


title:
Why $T_c$ of (CaFeAs)$_{10}$Pt$_{3.58}$As$_8$ is twice as high as
  (CaFe$_{0.95}$Pt$_{0.05}$As)$_{10}$Pt$_3$As$_8$

abstract:
  Recently discovered (CaFe$_{1-x}$Pt$_x$As)$_{10}$Pt$_3$As$_8$ and
(CaFeAs)$_{10}$Pt$_{4-y}$As$_8$ superconductors are very similar materials
having the same elemental composition and structurally similar superconducting
FeAs slabs. Yet the maximal critical temperature achieved by changing Pt
concentration is approximately twice higher in the latter. Using angle-resolved
photoemission spectroscopy(ARPES) we compare the electronic structure of their
optimally doped compounds and find drastic differences. Our results highlight
the sensitivity of critical temperature to the details of fermiology and point
to the decisive role of band-edge singularities in the mechanism of high-$T_c$
superconductivity.


title: Spatiotemporal clustering and separation in regional earthquakes

abstract:
  Spatiotemporal clustering of earthquake events is a generally-established
fact, and is important for designing models and assessment techniques in
seismicity. Here, we investigate how this behavior can manifest in the
statistical distributions of inter-event distances and times between
earthquakes from different regional catalogs. We complement the analysis of
previous authors (Touati et al., PRL 102, 168501 (2009)) and observe histograms
best described by a superposition of two component distributions for "short"
and "long" distances and times. Our results quantify the spatiotemporal
clustering of earthquakes that are possibly generated by the same triggering
mechanism. Independent earthquakes, on the other hand, are found to be
separated by long inter-event distances and times. The statistics presented
reveal regional differences, suggesting non-universality of the distributions.


title: A note on the new q-extension of Frobenius-Euler numbers and polynomials

abstract:
  In this paper, we consider the new q-extension of Frobenius-Euler numbers and
polynomials and we derive some interesting identities from the orthogonality
type properties for the new q-extension of Frobenius-Euler polynomials. Finally
we suggest one open question related to orthogonality of polynomials.


title:
On the closedness of the sum of ranges of operators $A_k$ with almost
  compact products $A_i^* A_j$

abstract:
  Let $\mathcal{H}_1,\ldots,\mathcal{H}_n,\mathcal{H}$ be complex Hilbert
spaces and $A_k:\mathcal{H}_k\to\mathcal{H}$ be a bounded linear operator with
the closed range $Ran(A_k)$, $k=1,\ldots,n$. It is known that if $A_i^*A_j$ is
compact for any $i\neq j$, then $\sum_{k=1}^n Ran(A_k)$ is closed.
  We show that if all products $A_i^*A_j$, $i\neq j$ are "almost" compact, then
the subspaces $Ran(A_1),\ldots,Ran(A_n)$ are essentially linearly independent
and their sum is closed.


title:
A singularly perturbed Dirichlet problem for the Poisson equation in a
  periodically perforated domain. A functional analytic approach

abstract:
  Let $\Omega$ be a sufficiently regular bounded open connected subset of
$\mathbb{R}^n$ such that $0 \in \Omega$ and that $\mathbb{R}^n \setminus
\mathrm{cl}\Omega$ is connected. Then we take $(q_{11},\dots, q_{nn})\in
]0,+\infty[^n$ and $p \in Q\equiv \prod_{j=1}^{n}]0,q_{jj}[$. If $\epsilon$ is
a small positive number, then we define the periodically perforated domain
$\mathbb{S}[\Omega_{p,\epsilon}]^{-} \equiv \mathbb{R}^n\setminus \cup_{z \in
\mathbb{Z}^n}\mathrm{cl}\bigl(p+\epsilon \Omega +\sum_{j=1}^n
(q_{jj}z_j)e_j\bigr)$, where $\{e_1,\dots,e_n\}$ is the canonical basis of
$\mathbb{R}^n$. For $\epsilon$ small and positive, we introduce a particular
Dirichlet problem for the Poisson equation in the set
$\mathbb{S}[\Omega_{p,\epsilon}]^{-}$. Namely, we consider a Dirichlet
condition on the boundary of the set $p+\epsilon \Omega$, together with a
periodicity condition. Then we show real analytic continuation properties of
the solution as a function of $\epsilon$, of the Dirichlet datum on $p+\epsilon
\partial \Omega$, and of the Poisson datum, around a degenerate triple with
$\epsilon=0$.


title: Linear perturbations in viable f(R) theories

abstract:
  We describe the cosmological evolution predicted by three distinct $f(R)$
theories, with emphasis on the evolution of linear perturbations. The most
promising observational tools for distinguishing $f(R)$ theories from
$\Lambda$CDM are those intrinsically related to the growth of structure, such
as weak lensing. At the linear level, the enhancement in the gravitational
potential provided by the additional $f(R)$ `fifth force' can separate the
theories, whereas at the background level they can be indistinguishable. Under
the stringent constraints imposed on the models by Solar System tests and
galaxy-formation criteria, we show that the relative difference between the
models' linear evolution of the lensing potential will be extremely hard to
detect even with future space-based experiments such as {\it Euclid}, with a
maximum value of approximately 4% for small scales. We also show the evolution
of the gravitational potentials under more relaxed local constraint conditions,
where the relative difference between these models and $\Lambda$CDM could prove
discriminating.


title:
Quantum critical Kondo destruction in the Bose-Fermi Kondo model with a
  local transverse field

abstract:
  Recent studies of the global phase diagram of quantum-critical heavy-fermion
metals prompt consideration of the interplay between the Kondo interactions and
quantum fluctuations of the local moments alone. Toward this goal, we study a
Bose-Fermi Kondo model (BFKM) with Ising anisotropy in the presence of a local
transverse field that generates quantum fluctuations in the local-moment
sector. We apply the numerical renormalization-group method to the case of a
sub-Ohmic bosonic bath exponent and a constant conduction-electron density of
states. Starting in the Kondo phase at zero transverse-field, there is a smooth
crossover with increasing transverse field from a fully screened to a fully
polarized impurity spin. By contrast, if the system starts in its localized
phase, then increasing the transverse field causes a continuous,
Kondo-destruction transition into the partially polarized Kondo phase. The
critical exponents at this quantum phase transition exhibit hyperscaling and
take essentially the same values as those of the BFKM in zero transverse field.
The many-body spectrum at criticality varies continuously with the bare
transverse field, indicating a line of critical points. We discuss implications
of these results for the global phase diagram of the Kondo lattice model.


title: Partitions of a Finite Partially Ordered Set

abstract:
  In this paper, we investigate the notion of partition of a finite partially
ordered set (poset, for short). We will define three different notions of
partition of a poset, namely, monotone, regular, and open partition. For each
of these notions we will find three equivalent definitions, that will be shown
to be equivalent. We start by defining partitions of a poset in terms of fibres
of some surjection having the poset as domain. We then obtain combinatorial
characterisations of such notions in terms of blocks, without reference to
surjection. Finally, we give a further, equivalent definition of each kind of
partition by means of analogues of equivalence relations.


title: Laser molecular beam epitaxy of ZnO thin films and heterostructures

abstract:
  We report on the growth of epitaxial ZnO thin films and ZnO based
heterostructures on sapphire substrates by laser molecular beam epitaxy (MBE).
We first discuss some recent developments in laser-MBE such as flexible
ultra-violet laser beam optics, infrared laser heating systems or the use of
atomic oxygen and nitrogen sources, and describe the technical realization of
our advanced laser-MBE system. Then we describe the optimization of the
deposition parameters for ZnO films such as laser fluence and substrate
temperature and the use of buffer layers. The detailed structural
characterization by x-ray analysis and transmission electron microscopy shows
that epitaxial ZnO thin films with high structural quality can be achieved, as
demonstrated by a small out-of-plane and in-plane mosaic spread as well as the
absence of rotational domains. We also demonstrate the heteroepitaxial growth
of ZnO based multilayers as a prerequisite for spin transport experiments and
the realization of spintronic devices. As an example, we show that
TiN/Co/ZnO/Ni/Au multilayer stacks can be grown on (0001)-oriented sapphire
with good structural quality of all layers and well defined in-plane epitaxial
relations.


title: Perturbations of geodesic flows by recurrent dynamics

abstract:
  We consider a geodesic flow on a compact manifold endowed with a Riemannian
(or Finsler, or Lorentz) metric satisfying some generic, explicit conditions.
We couple the geodesic flow with a time-dependent potential, driven by an
external flow on some other compact manifold. If the external flow satisfies
some very general recurrence condition, and the potential satisfies some
explicit conditions that are also very general, we show that the coupled system
has orbits whose energy grows at a linear rate with respect to time. This
growth rate is optimal. We also show the existence of symbolic dynamics. The
existence of orbits whose energy grows unboundedly in time is related to
Arnold's diffusion problem. A particular case of this phenomenon is obtained
when the external dynamical system is quasi-periodic, of rationally independent
frequency vector, not necessarily Diophantine, thus extending earlier results.
We also recover `Mather's acceleration theorem' for time-periodic
perturbations. Since the general class of perturbations that we consider in
this paper are not characterized by a frequency of motion, we are not able to
use KAM or Aubry-Mather or averaging theory. We devise a new mechanism to
construct orbits whose energy evolves in a prescribed fashion. This mechanism
intertwines the inner dynamics restricted to some normally hyperbolic manifold
with the outer dynamics corresponding to two distinct choices of homoclinic
excursions to that manifold. As this mechanism uses very coarse information on
the dynamics, it is potentially of wider applicability.


title: Photoacoustic and thermoacoustic tomography with an uncertain wave speed

abstract:
  We consider the mathematical model of photoacoustic and thermoacoustic
tomography in media with a variable sound speed. When the sound speed is known,
the explicit reconstruction formula by P. Stefanov and G. Uhlmann (Inverse
Problems, 25(7):075011, 16, 2009) can be used. We study how a modelling error
in the sound speed affects the reconstruction formula and quantify the effect
in terms of a stability estimate.


title:
Micromanipulation transfer of membrane resonators for circuit
  optomechanics

abstract:
  A capacitive coupling between mechanical resonator and a microwave cavity
enables readout and manipulation of the vibrations. We present a setup to carry
out such experiments with aluminum membranes fabricated as stamps and
transferred in place with micromanipulation. The membrane is held in place by
van der Waals forces, and is supported by three microscopic points. We measure
the lowest mechanical modes, and conclude the membrane vibrates as an
essentially free-free resonator. Sliding clamping conditions are identified via
a softening Duffing nonlinearity. The method will enable reduction of clamping
losses, while maintaining a narrow vacuum gap for strong capacitive coupling.


title:
A general, efficient and robust method to calculate free energy
  difference between systems

abstract:
  Calculating free energy differences is a topic of substantial interest and
has many applications including molecular docking and hydration, solvation, and
binding free energies which is used in computational drug discovery. However,
in equilibrium methods the compared molecules are required to have large phase
space overlap, which is usually not satisfied for two random systems, and there
remain the challenges of robustness and automation. Here a highly efficient and
robust method, that enables a wide range of comparisons, will be introduced,
demonstrated and compared. In this method instead of transforming between one
system into the other to perform the calculation each system is transformed
into its replica with the different long range energy terms relaxed, which is
inherently correlated with the original one, in order to eliminate the
partition function difference arising from these terms. Then, since each
transformed system can be treated as non interacting systems, the remaining
difference in the (originally highly complex) partition function will cancel
out.


title: High density effects in ultrahigh neutrino interactions

abstract:
  The high parton density present at high energies and large nuclei is expected
to modify the lepton - hadron cross section and the associated observables. In
this paper we analyse the impact of the high density effects in the average
inelasticity and the neutrino - nucleus cross section at ultra high energies.
We compare the predictions associated to the linear DGLAP dynamics with those
from the Color Glass Condensate formalism, which includes non-linear effects.
Our results demonstrated that the non-linear effects reduce the average
inelasticity and that the predictions of the distinct approaches for the
neutrino - nucleus cross section at ultra-high energies are similar.


title:
Can a planet explain different cavity sizes for small and large dust
  grains in transition disks?

abstract:
  Dissimilarities in the spatial distribution of small (micron-size) and large
(millimeter-size) dust grains at the cavity edge of transition disks have been
recently pointed out and are now under debate. We obtained VLT-NACO near-IR
polarimetric observations of SAO 206462 (HD135344B). The disk around the star
shows very complex structures, such as dips and spirals. We also find an inner
cavity much smaller than what inferred from sub-mm images. The interaction
between disk and orbiting companion(s) may explain this discrepancy.


title:
Design parameters for voltage-controllable directed assembly of single
  nanoparticles

abstract:
  Techniques to reliably pick and place single nanoparticles into functional
assemblies are required to incorporate exotic nanoparticles into standard
electronic circuits. In this paper we explore the use of electric fields to
drive and direct the assembly process, which has the advantage of being able to
control the nano-assembly process at the single nanoparticle level. To achieve
this, we design an electrostatic gating system, thus enabling a voltage
controllable nanoparticle picking technique. Using the nonlinear
Poisson-Boltzmann equation, we can successfully characterise the parameters
required for single-particle placement, the key being single particle
selectivity, in effect designing a system that can achieve this controllably.
We then present the optimum design parameters required for successful single
nanoparticle placements at ambient temperatures, an important requirement for
nanomanufacturing processes.


title:
Unitary Representations of Lattices of Free Nilpotent Lie Groups of
  Step-Two

abstract:
  Using a theorem proved by Bekka and Driutti, we show that if $\mathfrak{f}$
is a freely generated nilpotent Lie algebra of step-two, then almost every
irreducible representation of the corresponding Lie group restricted to some
lattice $\Gamma$ is an irreducible representation of $\Gamma$ if the dimension
of the Lie algebra is odd. However, if the dimension of the Lie algebra is
even, then almost every unitary irreducible representation of the Lie group
restricted to $\Gamma$ is reducible.


title:
Robust Causality Check for Sampled Scattering Parameters via a Filtered
  Fourier Transform

abstract:
  We introduce a robust numerical technique to verify the causality of sampled
scattering parameters given on a finite bandwidth. The method is based on a
filtered Fourier transform and includes a rigorous estimation of the errors
caused by missing out-of-band samples. Compared to existing techniques, the
method is simpler to implement and provides a useful insight on the time-domain
characteristics of the detected violation. Through an applicative example, we
shows its usefulness to improve the accuracy and reliability of macromodeling
techniques used to convert sampled scattering parameters into models for
transient analysis.


title: On convergence rates in approximation theory for operator semigroups

abstract:
  We create a new, functional calculus, approach to approximation of
C_0-semigroups on Banach spaces. As an application of this approach, we obtain
optimal convergence rates in classical approximation formulas for
C_0-semigroups. In fact, our methods allow one to derive a number of similar
formulas and equip them with sharp convergence rates. As a byproduct, we prove
a new interpolation principle leading to efficient norm estimates in the Banach
algebra of Laplace transforms of bounded measures on the semi-axis.


title: Computing Puiseux Expansions at Cusps of the Modular Curve X0(N)

abstract:
  The goal in this preprint is to give an efficient algorithm to compute
Puiseux expansions at cusps of X0(N). It is based on a relation with a
hypergeometric function that holds for any N.


title: A Population of Fast Radio Bursts at Cosmological Distances

abstract:
  Searches for transient astrophysical sources often reveal unexpected classes
of objects that are useful physical laboratories. In a recent survey for
pulsars and fast transients we have uncovered four millisecond-duration radio
transients all more than 40{\deg} from the Galactic plane. The bursts'
properties indicate that they are of celestial rather than terrestrial origin.
Host galaxy and intergalactic medium models suggest that they have cosmological
redshifts of 0.5 to 1, and distances of up to 3 gigaparsecs. No temporally
coincident x- or gamma-ray signature was identified in association with the
bursts. Characterization of the source population and identification of host
galaxies offers an opportunity to determine the baryonic content of the
Universe.


title: Symplectic Lie Groups I-III

abstract:
  We develop the structure theory of symplectic Lie groups based on the study
of their isotropic normal subgroups. The article consists of three main parts.
In the first part we show that every symplectic Lie group admits a sequence of
subsequent symplectic reductions to a unique irreducible symplectic Lie group.
The second part concerns the symplectic geometry of cotangent symplectic Lie
groups and the theory of Lagrangian extensions of flat Lie groups. In the third
part of the article we analyze the existence problem for Lagrangian normal
subgroups in nilpotent symplectic Lie groups.


title:
Power Allocation Strategies in Energy Harvesting Wireless Cooperative
  Networks

abstract:
  In this paper, a wireless cooperative network is considered, in which
multiple source-destination pairs communicate with each other via an energy
harvesting relay. The focus of this paper is on the relay's strategies to
distribute the harvested energy among the multiple users and their impact on
the system performance. Specifically, a non-cooperative strategy is to use the
energy harvested from the i-th source as the relay transmission power to the
i-th destination, to which asymptotic results show that its outage performance
decays as logSNR over SNR. A faster decaying rate, 1 over SNR, can be achieved
by the two centralized strategies proposed this the paper, where the water
filling based one can achieve optimal performance with respect to several
criteria, with a price of high complexity. An auction based power allocation
scheme is also proposed to achieve a better tradeoff between the system
performance and complexity. Simulation results are provided to confirm the
accuracy of the developed analytical results and facilitate a better
performance comparison.


title: Scalar, spinor, and photon fields under relativistic cavity motion

abstract:
  We analyse quantised scalar, spinor and photon fields in a mechanically rigid
cavity that is accelerated in Minkowski spacetime, in a recently-introduced
perturbative small acceleration formalism that allows the velocities to become
relativistic, with a view to applications in relativistic quantum information.
A scalar field is analysed with both Dirichlet and Neumann boundary conditions,
and a photon field under perfect conductor boundary conditions is shown to
decompose into Dirichlet-like and Neumann-like polarisation modes. The Dirac
spinor is analysed with a nonvanishing mass and with dimensions transverse to
the acceleration, and the MIT bag boundary condition is shown to exclude zero
modes. Unitarity of time evolution holds for smooth accelerations but fails for
discontinuous accelerations in spacetime dimensions (3+1) and higher. As an
application, the experimental desktop mode-mixing scenario proposed for a
scalar field by Bruschi et al. [New J. Phys. 15, 073052 (2013)] is shown to
apply also to the photon field.


title:
Gupta-Bleuler Quantization of the Maxwell Field in Globally Hyperbolic
  Space-Times

abstract:
  We give a complete framework for the Gupta-Bleuler quantization of the free
electromagnetic field on globally hyperbolic space-times. We describe
one-particle structures that give rise to states satisfying the microlocal
spectrum condition. The field algebras in the so-called Gupta-Bleuler
representations satisfy the time-slice axiom, and the corresponding vacuum
states satisfy the microlocal spectrum condition. We also give an explicit
construction of ground states on ultrastatic space-times. Unlike previous
constructions, our method does not require a spectral gap or the absence of
zero modes. The only requirement, the absence of zero-resonance states, is
shown to be stable under compact perturbations of topology and metric. Usual
deformation arguments based on the time-slice axiom then lead to a construction
of Gupta-Bleuler representations on a large class of globally hyperbolic
space-times. As usual, the field algebra is represented on an indefinite inner
product space, in which the physical states form a positive semi-definite
subspace. Gauge transformations are incorporated in such a way that the field
can be coupled perturbatively to a Dirac field. Our approach does not require
any topological restrictions on the underlying space-time.


title: The number of reducible space curves over a finite field

abstract:
  "Most" hypersurfaces in projective space are irreducible, and rather precise
estimates are known for the probability that a random hypersurface over a
finite field is reducible. This paper considers the parametrization of space
curves by the appropriate Chow variety, and provides bounds on the probability
that a random curve over a finite field is reducible.


title: On Mpc-structures and Symplectic Dirac Operators

abstract:
  We prove that the kernels of the restrictions of symplectic Dirac or
symplectic Dirac-Dolbeault operators on natural subspaces of polynomial valued
spinor fields are finite dimensional on a compact symplectic manifold. We
compute those kernels for the complex projective spaces. We construct
injections of subgroups of the symplectic group (the pseudo-unitary group and
the stabilizer of a Lagrangian subspace) in the group Mpc and classify
G-invariant Mpc-structures on symplectic spaces with a G-action. We prove a
variant of Parthasarathy's formula for the commutator of two symplectic
Dirac-type operators on a symmetric symplectic space.


title: Fredholm theory for band-dominated and related operators: a survey

abstract:
  This paper presents the Fredholm theory on l^p-spaces for band-dominated
operators and important subclasses, such as operators in the Wiener algebra. It
particularly closes several gaps in the previously known results for the case
p=\infty and addresses the open questions raised in a paper by Chandler-Wilde
and Lindner. The main tools are provided by the limit operator method and an
algebraic framework for the description and adaption of Fredholmness and
convergence. A comprehensive overview of this approach is given.


title:
Palmer-Chalker correlations in the XY pyrochlore antiferromagnet
  Er2Sn2O7

abstract:
  \ersn\, is considered, together with \erti, as a realization of the XY
antiferromagnet on the pyrochlore lattice. We present magnetization
measurements confirming that \ersn\, does not order down to 100 mK but exhibits
a freezing below 200 mK. Our neutron scattering experiments evidence the strong
XY character of the \er moment and point out the existence of short range
correlations in which the magnetic moments are in peculiar configurations, the
Palmer-Chalker states, predicted theoretically for an XY pyrochlore
antiferromagnet with dipolar interactions. Our estimation of the \ersn\,
parameters confirm the role of the latter interactions on top of relatively
weak and isotropic exchange couplings.


title:
Extension of the B3LYP - Dispersion-Correcting Potential Approach to the
  Accurate Treatment of both Inter- and Intramolecular Interactions

abstract:
  We recently showed that dispersion-correcting potentials (DCPs),
atom-centered Gaussian-type functions developed for use with B3LYP (J. Phys.
Chem. Lett. 2012, 3, 1738-1744) greatly improved the ability of the underlying
functional to predict non-covalent interactions. However, the application of
B3LYP-DCP for the {\beta}-scission of the cumyloxyl radical led a calculated
barrier height that was over-estimated by ca. 8 kcal/mol. We show in the
present work that the source of this error arises from the previously developed
carbon atom DCPs, which erroneously alters the electron density in the C-C
covalent-bonding region. In this work, we present a new C-DCP with a form that
was expected to influence the electron density farther from the nucleus. Tests
of the new C-DCP, with previously published H-, N- and O-DCPs, with
B3LYP-DCP/6-31+G(2d,2p) on the S66, S22B, HSG-A, and HC12 databases of
non-covalently interacting dimers showed that it is one of the most accurate
methods available for treating intermolecular interactions, giving mean
absolute errors (MAEs) of 0.19, 0.27, 0.16, and 0.18 kcal/mol, respectively.
Additional testing on the S12L database of complexation systems gave an MAE of
2.6 kcal/mol, showing that the B3LYP-DCP/6-31+G(2d,2p) approach is one of the
best-performing and feasible methods for treating large systems dominated by
non-covalent interactions. Finally, we showed that C-C making/breaking
chemistry is well-predicted using the newly developed DCPs. In addition to
predicting a barrier height for the {\beta}-scission of the cumyloxyl radical
that is within 1.7 kcal/mol of the high-level value, application of
B3LYP-DCP/6-31+G(2d,2p) to 10 databases that include reaction barrier heights
and energies, isomerization energies and relative conformation energies gives
performance that is amongst the best of all available dispersion-corrected
density-functional theory approaches.


title: Ramification and nearby cycles for l-adic sheaves on relative curves

abstract:
  Deligne and Kato proved a formula computing the dimension of the nearby
cycles complex of an l-adic sheaf on a relative curve over an excellent
strictly henselian trait. In this article, we reprove this formula using
Abbes-Saito's ramification theory.


title: Unconventional superfluidity in quasi-one-dimensional systems

abstract:
  We show that an unconventional superfluid triggered by spin-orbit coupling is
realized for repulsively interacting quasi-one-dimensional fermions. A
competition between spin-singlet and -triplet pairings occurs due to the
breaking of inversion symmetry. We show that both superfluid correlations decay
algebraically with the same exponent except for special coupling constants for
which a dominant superfluid is controlled by the spin-orbit coupling. We also
discuss a possible experiment to observe such phases with cold atoms.


title: Automorphy and irreducibility of some l-adic representations

abstract:
  In this paper we prove that a pure, regular, totally odd, polarizable weakly
compatible system of $l$-adic representations is potentially automorphic. The
innovation is that we make no irreducibility assumption, but we make a purity
assumption instead. For compatible systems coming from geometry, purity is
often easier to check than irreducibility. We use Katz's theory of rigid local
systems to construct many examples of motives to which our theorem applies. We
also show that if $F$ is a CM or totally real field and if $\pi$ is a
polarizable, regular algebraic, cuspidal automorphic representation of
$GL_n(\A_F)$, then for a positive Dirichlet density set of rational primes $l$,
the $l$-adic representations $r_{l,\imath}(\pi)$ associated to $\pi$ are
irreducible.


title: \alpha-Decay in Ultra-Intense Laser Fields

abstract:
  We investigate the \alpha-decay of a spherical nucleus under the influence of
an ultra-intense laser field for the case when the radius vector joining the
center-of-masses of the \alpha-particle and the daughter is aligned with the
direction of the external field. The time-independent part of the
\alpha-daughter interaction is taken from elastic scattering compilations
whereas the time-varying part describes the interaction between the decaying
system with the laser field. The time-dependent Schr\"odinger equation is
solved numerically by appealing to a modified scheme of the Crank-Nicolson type
where an additional first-order time derivative appears compared to the
field-free case. The tunneling probability of the \alpha-cluster, and derived
quantities (decay rate, total flux) is determined for various laser intensities
and frequencies for either continous waves or few-cycle pulses of envelope
function F(t)=1. We show that in the latter case pulse sequences containing an
odd number of half-cycles determine an enhancement of the tunneling probability
compared to the field-free case and the continuous wave case. The present study
is carried out taking as example the alpha decaying nucleus $^{106}$Te.


title: Effective Light Dynamics in Perturbed Photonic Crystals

abstract:
  In this work, we rigorously derive effective dynamics for light from within a
limited frequency range propagating in a photonic crystal that is modulated on
the macroscopic level; the perturbation parameter $\lambda \ll 1$ quantifies
the separation of spatial scales. We do that by rewriting the dynamical Maxwell
equations as a Schr\"odinger-type equation and adapting space-adiabatic
perturbation theory. Just like in the case of the Bloch electron, we obtain a
simpler, effective Maxwell operator for states from within a relevant almost
invariant subspace. A correct physical interpretation for the effective
dynamics requires to establish two additional facts about the almost invariant
subspace: (1) The source-free condition has to be verified and (2) it has to
support real states. The second point also forces one to consider a multiband
problem even in the simplest possible setting; This turns out to be a major
difficulty for the extension of semiclassical methods to the domain of photonic
crystals.


title:
Collision parameters governing water delivery and water loss in early
  planetary systems

abstract:
  We investigate the distribution of encounter velocities and impact angles
describing collisions in the habitable zone of the early planetary system. Here
we present a catalogue of collision characteristics for a particular mass ratio
of the colliding bodies and seven different planetesimal masses ranging from a
tenth of Ceres' mass to 10 times the mass of the Moon. We show that there are
virtually no collisions with impact speeds lower than the surface escape
velocity and a similar velocity-impact angle distribution for different
planetesimal masses if velocities are normalized using the escape velocity. An
additional perturbing Jupiter-like object distorts the collision velocity and
impact picture in the sense that grazing impacts at higher velocities are
promoted if the perturber's orbit is close to the habitable zone whereas a more
distant perturber has more the effect of a mere widening of the velocity
dispersion.


title:
DFT-GGA errors in NO chemisorption energies on (111) transition metal
  surfaces: Possible origins and correction schemes

abstract:
  Here we investigate whether well-known DFT-GGA errors in predicting the
chemisorption energy ($E_{\rm chem}$) of CO on transition metal surfaces
manifest in analogous NO chemisorption systems. To verify the occurrence of
DFT-GGA overestimation of the back-donation mechanism in NO Chemisorption, we
use electronic structure analysis to show that the partially filled molecular
NO 2$\pi^{*}$ orbital rehybridizes with the transition metal $d$-band to form
new bonding and anti-bonding states. We relate the back-donation charge
transfer associated with chemisorption to the promotion of an electron from the
5$\sigma$ orbital to the 2$\pi^{*}$ orbital in the gas-phase NO
G$^{2}\Sigma^{-}\leftarrow \rm{X}^{2}\Pi$ excitation. We establish linear
relationships between $E_{\rm chem}$ and $\Delta E_{\rm G\leftarrow X}$ and go
on to formulate an $E_{\rm chem}$ correction scheme in the style of Mason {\it
et al.}, {[Physical Review B {\bf 69}, 161401(R)]}. We apply the NO $E_{\rm
chem}$ correction method to the (111) surfaces of Pt, Pd, Rh, and Ir, with NO
chemisorption modeled at a coverage of 0.25 ML. We note that both the slope of
$E_{\rm chem}$ {\it vs.} $\Delta E_{\rm G\leftarrow X}$ and the dipole moment
depend strongly on adsorption site for each metal, and we use this fact to
construct an approximate correction scheme which we go on to test using
NO/Pt(100) chemisorption.


title:
Room temperature compressibility and diffusivity of liquid water from
  first principles

abstract:
  The isothermal compressibility of water is essential to understand its
anomalous properties. We compute it by ab initio molecular dynamics simulations
of 200 molecules at five densities, using two different van der Waals density
functionals. While both functionals predict compressibilities within ~30% of
experiment, only one of them accurately reproduces, within the uncertainty of
the simulation, the density dependence of the self-diffusion coefficient in the
anomalous region. The discrepancies between the two functionals are explained
in terms of the low- and high-density structures of the liquid.


title: On the density of shear transformation zones in amorphous solids

abstract:
  We study the stability of amorphous solids, focusing on the distribution P(x)
of the local stress increase x that would lead to an instability. We argue that
this distribution is singular P(x)x^{\theta}, where the exponent {\theta} is
non-zero if the elastic interaction between rearranging regions is
non-monotonic, and increases with the interaction range. For a class of finite
dimensional models we show that stability implies a lower bound on {\theta},
which is found to lie near saturation. For quadrupolar interactions these
models yield {\theta} ~ 0.6 for d=2 and \theta ~ 0.4 in d=3 where d is the
spatial dimension, accurately capturing previously unresolved observations in
atomistic models, both in quasi-static flow and after a fast quench.


title:
Electromagnetic and Potential Scattering from a Radially Inhomogeneous
  Sphere

abstract:
  Aspects of of plane wave electromagnetic scattering by a radially
inhomogeneous sphere is discussed. The vector problem is reduced to two scalar
radial `Schr\"odinger-like' equations, and a connection with time-independent
potential scattering theory is exploited to draw several conclusions about
specific refractive index profiles.


title:
Slingshot Dynamics for Self Replicating Probes and the Effect on
  Exploration Timescales

abstract:
  Interstellar probes can carry out slingshot manoeuvres around the stars they
visit, gaining a boost in velocity by extracting energy from the star's motion
around the Galactic Centre. These maneouvres carry little to no extra energy
cost, and in previous work it has been shown that a single Voyager-like probe
exploring the galaxy does so 100 times faster when carrying out these
slingshots than when navigating purely by powered flight (Forgan et al. 2012).
We expand on these results by repeating the experiment with self-replicating
probes. The probes explore a box of stars representative of the local Solar
neighbourhood, to investigate how self-replication affects exploration
timescales when compared with a single non-replicating probe.
  We explore three different scenarios of probe behaviour: i) standard powered
flight to the nearest unvisited star (no slingshot techniques used), ii) flight
to the nearest unvisited star using slingshot techniques, and iii) flight to
the next unvisited star that will give the maximum velocity boost under a
slingshot trajectory.
  In all three scenarios we find that as expected, using self-replicating
probes greatly reduces the exploration time, by up to three orders of magnitude
for scenario i) and iii) and two orders of magnitude for ii). The second case
(i.e. nearest-star slingshots) remains the most time effective way to explore a
population of stars. As the decision-making algorithms for the fleet are
simple, unanticipated "race conditions" amongst probes are set up, causing the
exploration time of the final stars to become much longer than necessary. From
the scaling of the probes' performance with star number, we conclude that a
fleet of self-replicating probes can indeed explore the Galaxy in a
sufficiently short time to warrant the existence of the Fermi Paradox.