title:
First results on low-mass WIMP from the CDEX-1 experiment at the China
  Jinping underground Laboratory

abstract:
  The China Dark matter Experiment collaboration reports the first experimental
limit on WIMP dark matter from 14.6 kg-day of data taken with a 994 g p-type
point-contact germanium detector at the China Jinping underground Laboratory
where the rock overburden is more than 2400 m. The energy threshold achieved
was 400 eVee. According to the 14.6 kg-day live data, we placed the limit of N=
1.75 * 10^{-40} cm^{2} at 90% confidence level on the spin-independent
cross-section at WIMP mass of 7 GeV before differentiating bulk signals from
the surface backgrounds.


title:
Dynamical interplay between awareness and epidemic spreading in
  multiplex networks

abstract:
  We present the analysis of the interrelation between two processes accounting
for the spreading of an epidemics, and the information awareness to prevent its
infection, on top of multiplex networks. This scenario is representative of an
epidemic process spreading on a network of persistent real contacts, and a
cyclic information awareness process diffusing in the network of virtual social
contacts between the same individuals. The topology corresponds to a multiplex
network where two diffusive processes are interacting affecting each other. The
analysis using a Microscopic Markov Chain Approach (MMCA) reveals the phase
diagram of the incidence of the epidemics and allows to capture the evolution
of the epidemic threshold depending on the topological structure of the
multiplex and the interrelation with the awareness process. Interestingly, the
critical point for the onset of the epidemics has a critical value
(meta-critical point) defined by the awareness dynamics and the topology of the
virtual network, from which the onset increases and the epidemics incidence
decreases.


title: Quantum communication without the necessity of quantum memories

abstract:
  Quantum physics is known to allow for completely new ways to create,
manipulate and store information. Quantum communication - the ability to
transmit quantum information - is a primitive necessary for any quantum
internet. At its core, quantum communication generally requires the formation
of entangled links between remote locations. The performance of these links is
limited by the classical signaling time between such locations - necessitating
the need for long lived quantum memories. Here we present the design of a
communications network which neither requires the establishment of entanglement
between remote locations nor the use of long-lived quantum memories. The rate
at which quantum data can be transmitted along the network is only limited by
the time required to perform efficient local gate operations. Our scheme thus
potentially provides higher communications rates than previously thought
possible.


title: A dynamical CP source for CKM, PMNS and Leptogenesis

abstract:
  We propose a simple model for the spontaneous CP violation based on
$SU(2)_{L}\times U(1)_{Y}\times A_{4}\times CP\times Z_{2}$ symmetry for quarks
and leptons in a seesaw framework. In our model CP is spontaneously broken at
high energies, after breaking of flavor symmetry, by a complex vacuum
expectation value of $A_{4}$-triplet and gauge singlet scalar field. And,
certain effective dimension-5 operators are introduced in the quark Lagrangian
as an equal footing, which lead the quark mixing matrix to the
Cabibbo-Kobayashi-Maskawa (CKM) one in the form, while the lepton Lagrangian is
renormalizable, which gives rise to a non-degenerate Dirac neutrino Yukawa
matrix and an unique CP-phase, and which in turn explains the non-zero value of
$\theta_{13}\simeq9^{\circ}$ and two large mixing angles $\theta_{12},
\theta_{23}$. We show that the spontaneously generated CP phase "$\xi$" could
become a natural source of leptogenesis as well as CP violations in the CKM and
Pontecorvo-Maki-Nakagawa-Sakata (PMNS). Moreover, we provide a solution for the
strong CP problem. Interestingly enough, we show that, for around
$\xi\simeq120^{\circ}$, the quarks lead to the correct CKM CP-phase
corresponding to $\delta^{q}_{CP}\simeq67^{\circ}$, while the leptons with the
measured value of $\theta_{13}$ favor $\delta_{CP}=$,
$|\theta_{23}-45^{\circ}|\rightarrow0$ for normal mass hierarchy and
$\delta_{CP}=$, $|\theta_{23}-45^{\circ}|\rightarrow5^{\circ}$ for inverted
one. As a numerical study in the lepton sector, we show low-energy
phenomenologies and leptogenesis for the normal and inverted case,
respectively, and a link between them.


title: Punjabi Language Interface to Database: a brief review

abstract:
  Unlike most user-computer interfaces, a natural language interface allows
users to communicate fluently with a computer system with very little
preparation. Databases are often hard to use in cooperating with the users
because of their rigid interface. A good NLIDB allows a user to enter commands
and ask questions in native language and then after interpreting respond to the
user in native language. For a large number of applications requiring
interaction between humans and the computer systems, it would be convenient to
provide the end-user friendly interface. Punjabi language interface to database
would proof fruitful to native people of Punjab, as it provides ease to them to
use various e-governance applications like Punjab Sewa, Suwidha, Online Public
Utility Forms, Online Grievance Cell, Land Records Management System,legacy
matters, e-District, agriculture, etc. Punjabi is the mother tongue of more
than 110 million people all around the world. According to available
information, Punjabi ranks 10th from top out of a total of 6,900 languages
recognized internationally by the United Nations. This paper covers a brief
overview of the Natural language interface to database, its different
components, its advantages, disadvantages, approaches and techniques used. The
paper ends with the work done on Punjabi language interface to database and
future enhancements that can be done.


title:
On the existence of the relative equilibria of a rigid body in the J2
  problem

abstract:
  The motion of a point mass in the J2 problem has been generalized to that of
a rigid body in a J2 gravity field for new high-precision applications in the
celestial mechanics and astrodynamics. Unlike the original J2 problem, the
gravitational orbit-rotation coupling of the rigid body is considered in the
generalized problem. The existence and properties of both the classical and
non-classical relative equilibria of the rigid body are investigated in more
details in the present paper based on our previous results. We
nondimensionalize the system by the characteristic time and length to make the
study more general. Through the study, it is found that the classical relative
equilibria can always exist in the real physical situation. Numerical results
suggest that the non-classical relative equilibria only can exist in the case
of a negative J2, i.e., the central body is elongated; they cannot exist in the
case of a positive J2 when the central body is oblate. In the case of a
negative J2, the effect of the orbit-rotation coupling of the rigid body on the
existence of the non-classical relative equilibria can be positive or negative,
which depends on the values of J2 and the angular velocity. The bifurcation
from the classical relative equilibria, at which the non-classical relative
equilibria appear, has been shown with different parameters of the system. Our
results here have given more details of the relative equilibria than our
previous paper, in which the existence conditions of the relative equilibria
are derived and primarily studied. Our results have also extended the previous
results on the relative equilibria of a rigid body in a central gravity field
by taking into account the oblateness of the central body.


title:
Minimum Degree of the Difference of Two Polynomials over Q, and Weighted
  Plane Trees

abstract:
  A weighted bicolored plane tree is a bicolored plane tree whose edges are
endowed with positive integral weights. The degree of a vertex is defined as
the sum of the weights of the edges incident to this vertex. Using the theory
of dessins d'enfants, which studies the action of the absolute Galois group on
graphs embedded into Riemann surfaces, we show that a weighted plane tree is a
graphical representation of a pair of coprime complex polynomials A,B such
that: (a) deg A = deg B, and A and B have the same leading coefficient; (b) the
multiplicities of the roots of A (respectively, of B) are equal to the degrees
of the black (respectively, white) vertices of the corresponding tree; (c) the
degree of the difference A-B attains the minimum which is possible for the
given multiplicities of the roots of A and B. Moreover, if a tree in question
is uniquely determined by the set of its black and white vertex degrees (we
call such trees unitrees), then the corresponding polynomials are defined over
Q.
  The pairs of polynomials A,B such that the degree of the difference A-B
attains the minimum, and especially those defined over Q, are related to some
important questions of number theory. Dozens of papers were dedicated to their
study. The main result of this paper is a complete classification of the
unitrees which provides us with the most massive class of such pairs defined
over Q. We also study combinatorial invariants of the Galois action on trees,
as well as on the corresponding polynomial pairs, which permit us to find yet
more examples defined over Q. In a subsequent paper we compute the polynomials
A,B corresponding to all the unitrees.


title: Natural occupation numbers: When do they vanish?

abstract:
  The non-vanishing of the natural orbital occupation numbers of the
one-particle density matrix of many-body systems has important consequences for
the existence of a density matrix-potential mapping for nonlocal potentials in
reduced density matrix functional theory and for the validity of the extended
Koopmans' Theorem. On the basis of Weyl's theorem we give a connection between
the differentiability properties of the ground state wave function and the rate
at which the natural occupations approach zero when ordered as a descending
series. We show, in particular, that the presence of a Coulomb cusp in the wave
function leads, in general, to a power law decay of the natural occupations,
whereas infinitely differentiable wave-functions typically have natural
occupations that decay exponentially. We analyze for a number of explicit
examples of two-particle systems that in case the wave function is non-analytic
at its spatial diagonal (for instance, due to the presence of a Coulomb cusp)
the natural orbital occupations are non-vanishing. We further derive a more
general criterium for the non-vanishing of NO occupations for two-particle wave
functions with a certain separability structure. On the basis of this criterium
we show that for a two-particle system of harmonically confined electrons with
a Coulombic interaction (the so-called Hookium) the natural orbital occupations
never vanish.


title: On the Fukaya category of a Fano hypersurface in projective space

abstract:
  This paper is about the Fukaya category of a Fano hypersurface $X \subset
\mathbb{CP}^n$. Because these symplectic manifolds are monotone, both the
analysis and the algebra involved in the definition of the Fukaya category
simplify considerably. The first part of the paper is devoted to establishing
the main structures of the Fukaya category in the monotone case: the
closed-open string maps, weak proper Calabi-Yau structure, Abouzaid's
split-generation criterion, and their analogues when weak bounding cochains are
included. We then turn to computations of the Fukaya category of the
hypersurface $X$: we construct a configuration of monotone Lagrangian spheres
in $X$, and compute the associated disc potential. The result coincides with
the Hori-Vafa superpotential for the mirror of $X$ (up to a constant shift in
the Fano index $1$ case). As a consequence, we give a proof of Kontsevich's
homological mirror symmetry conjecture for $X$. We also explain how to extract
non-trivial information about Gromov-Witten invariants of $X$ from its Fukaya
category.


title:
Optimal Relay Placement for Capacity and Performance Improvement using a
  Fluid Model for Heterogeneous Wireless Networks

abstract:
  In this paper, we address the problem of optimal relay placement in a
cellular network assuming network densification, with the aim of maximizing
cell capacity. In our model, a fraction of radio resources is dedicated to the
base-station (BS)/relay nodes (RN) communication. In the remaining resources,
BS and RN transmit simultaneously to users. During this phase, the network is
densified in the sense that the transmitters density and so network capacity
are increased. Intra- and inter-cell interference is taken into account in
Signal to Interference plus Noise Ratio (SINR) simple formulas derived from a
fluid model for heterogeneous network. Optimization can then be quickly
performed using Simulated Annealing. Performance results show that cell
capacity is boosted thanks to densification despite a degradation of the signal
quality. Bounds are also provided on the fraction of resources dedicated to the
BS-RN link.


title:
Directed flow of charged particles at mid-rapidity relative to the
  spectator plane in Pb-Pb collisions at $\sqrt{s_\rm{NN}}$=2.76 TeV

abstract:
  The directed flow of charged particles at mid-rapidity is measured in Pb-Pb
collisions at $\sqrt{s_\rm{NN}}=2.76$ TeV relative to the collision symmetry
plane defined by the spectator nucleons. A negative slope of the rapidity-odd
directed flow component with approximately 3 times smaller magnitude than found
at the highest RHIC energy is observed. This suggests a smaller longitudinal
tilt of the initial system and disfavors the strong fireball rotation predicted
for the LHC energies. The rapidity-even directed flow component is measured for
the first time with spectators and found to be independent of pseudorapidity
with a sign change at transverse momenta $p_{\rm T}$ between $1.2$ and $1.7$
GeV/$c$. Combined with the observation of a vanishing rapidity-even $p_{\rm T}$
shift along the spectator deflection this is strong evidence for dipole-like
initial density fluctuations in the overlap zone of the nuclei. Similar trends
in the rapidity-even directed flow and the estimate from two-particle
correlations at mid-rapidity, which is larger by about a factor of 40, indicate
a weak correlation between fluctuating participant and spectator symmetry
planes. These observations open new possibilities for investigation of the
initial conditions in heavy-ion collisions with spectator nucleons.


title: Fermionic reflection matrices

abstract:
  We consider the insertion of integrable boundaries for a class of
supersymmetric quantum models. The generic conditions for constructing purely
bosonic, purely fermionic or mixed type solutions of the graded reflection
equation are extracted. Focusing on models associated with gl(m|n) or
Uq(gl(m|n)) symmetry, we first consider purely bosonic reflection matrices with
special structures, for general values of m, n. These solutions provide the
bosonic parts to construct fuller reflection matrices, containing fermionic
degrees of freedom as well.


title:
Feasibility guidelines for kaonic-atom experiments with
  ultra-high-resolution X-ray spectrometry

abstract:
  Recent studies of strong interaction effects in kaonic atoms suggest that
analysing so-called `lower' and `upper' levels in the same atom could separate
one-nucleon absorption from multinucleon processes. The present work examines
the feasibility of direct measurements of upper level widths in addition to
lower level widths in future experiments, using superconducting
microcalorimeter detectors. About ten elements are identified as possible
candidates for such experiments, all of medium-weight and heavy nuclei. New
experiments focused on achieving good accuracy for widths of such pairs of
levels could contribute significantly to our knowledge of the $K^-$-nucleon
interaction in the nuclear medium.


title: Aerodynamics of a rigid curved kite wing

abstract:
  A preliminary numerical study on the aerodynamics of a kite wing for high
altitude wind power generators is proposed. Tethered kites are a key element of
an innovative wind energy technology, which aims to capture energy from the
wind at higher altitudes than conventional wind towers. We present the results
obtained from three-dimensional finite volume numerical simulations of the
steady air flow past a three-dimensional curved rectangular kite wing (aspect
ratio equal to 3.2, Reynolds number equal to 3x10^6). Two angles of incidence
-- a standard incidence for the flight of a tethered airfoil (6{\deg}) and an
incidence close to the stall (18{\deg}) -- were considered. The simulations
were performed by solving the Reynolds Averaged Navier-Stokes flow model using
the industrial STAR-CCM+ code. The overall aerodynamic characteristics of the
kite wing were determined and compared to the aerodynamic characteristics of
the flat rectangular non twisted wing with an identical aspect ratio and
section (Clark Y profile). The boundary layer of both the curved and the flat
wings was considered to be turbulent throughout. It was observed that the
curvature induces only a mild deterioration of the aerodynamics properties.
Pressure distributions around different sections along the span are also
presented, together with isolines of the average pressure and kinetic energy
fields at a few sections across the wing and the wake. Our results indicate
that the curvature induces a slower spatial decay of the vorticity in the wake,
and in particular, inside the wing tip vortices.


title:
Exploring the limits of community detection strategies in complex
  networks

abstract:
  The characterization of network community structure has profound implications
in several scientific areas. Therefore, testing the algorithms developed to
establish the optimal division of a network into communities is a fundamental
problem in the field. We performed here a highly detailed evaluation of
community detection algorithms, which has two main novelties: 1) using complex
closed benchmarks, which provide precise ways to assess whether the solutions
generated by the algorithms are optimal; and, 2) A novel type of analysis,
based on hierarchically clustering the solutions suggested by multiple
community detection algorithms, which allows to easily visualize how different
are those solutions. Surprise, a global parameter that evaluates the quality of
a partition, confirms the power of these analyses. We show that none of the
community detection algorithms tested provide consistently optimal results in
all networks and that Surprise maximization, obtained by combining multiple
algorithms, obtains quasi-optimal performances in these difficult benchmarks.


title:
The role of local field modes in calculating the effective optical
  properties of metamaterials

abstract:
  This letter discusses the importance of the nature of local fields inside a
unit cell of optical metamaterials in developing a valid effective medium
theory. In particular, we apply the Meier-Wokaun procedure to derive a
corrected version of the Maxwell-Garnett formula for the refractive index of a
medium composed by metallic rods with subwavelength cross-section. We compare
this result with the values obtained using the full mode analysis calculated
via numerical simulations and analyze the impact of surface plasmon polaritons
in adequately determining the effective refractive index of the medium.


title: Computation in anonymous networks

abstract:
  We identify and investigate a computational model arising in molecular
computing, social computing and sensor network. The model is made of of
multiple agents who are computationally limited and posses no global
information. The agents may represent nodes in a social network, sensors, or
molecules in a molecular computer. Assuming that each agent is in one of $k$
states, we say that {\em the system computes} $f:[k]^{n} \to [k]$ if all agents
eventually converge to the correct value of $f$. We present number of general
results characterizing the computational power of the mode. We further present
protocols for computing the plurality function with $O(\log k)$ memory and for
approximately counting the number of nodes of a given color with $O(\log \log
n)$ memory, where $n$ is the number of agents in the networks. These results
are tight.


title: Bioclimating Modelling: A Machine Learning Perspective

abstract:
  Many machine learning (ML) approaches are widely used to generate bioclimatic
models for prediction of geographic range of organism as a function of climate.
Applications such as prediction of range shift in organism, range of invasive
species influenced by climate change are important parameters in understanding
the impact of climate change. However, success of machine learning-based
approaches depends on a number of factors. While it can be safely said that no
particular ML technique can be effective in all applications and success of a
technique is predominantly dependent on the application or the type of the
problem, it is useful to understand their behaviour to ensure informed choice
of techniques. This paper presents a comprehensive review of machine
learning-based bioclimatic model generation and analyses the factors
influencing success of such models. Considering the wide use of statistical
techniques, in our discussion we also include conventional statistical
techniques used in bioclimatic modelling.


title:
Combining Planck with Large Scale Structure gives strong neutrino mass
  constraint

abstract:
  We present the strongest current cosmological upper limit on the sum of
neutrino masses of < 0.18 (95% confidence). It is obtained by adding
observations of the large-scale matter power spectrum from the WiggleZ Dark
Energy Survey to observations of the cosmic microwave background data from the
Planck surveyor, and measurements of the baryon acoustic oscillation scale. The
limit is highly sensitive to the priors and assumptions about the neutrino
scenario. We explore scenarios with neutrino masses close to the upper limit
(degenerate masses), neutrino masses close to the lower limit where the
hierarchy plays a role, and addition of massive or massless sterile species.


title: The spin-polarized $\nu=0$ state of graphene: a spin superconductor

abstract:
  We study the spin-polarized $\nu=0$ Landau-level state of graphene. Due to
the electron-hole attractive interaction, electrons and holes can bound into
pairs. These pairs can then condense into a spin-triplet superfluid ground
state: a spin superconductor state. In this state, a gap opens up in the edge
bands as well as in the bulk bands, thus it is a charge insulator, but it can
carry the spin current without dissipation. These results can well explain the
insulating behavior of the spin-polarized $\nu=0$ state in the recent
experiments.


title:
Symbolic-numerical Algorithm for Generating Cluster Eigenfunctions:
  Tunneling of Clusters Through Repulsive Barriers

abstract:
  A model for quantum tunnelling of a cluster comprising A identical particles,
coupled by oscillator-type potential, through short-range repulsive potential
barriers is introduced for the first time in the new symmetrized-coordinate
representation and studied within the s-wave approximation. The
symbolic-numerical algorithms for calculating the effective potentials of the
close-coupling equations in terms of the cluster wave functions and the energy
of the barrier quasistationary states are formulated and implemented using the
Maple computer algebra system. The effect of quantum transparency, manifesting
itself in nonmonotonic resonance-type dependence of the transmission
coefficient upon the energy of the particles, the number of the particles
A=2,3,4, and their symmetry type, is analyzed. It is shown that the resonance
behavior of the total transmission coefficient is due to the existence of
barrier quasistationary states imbedded in the continuum.


title:
Improved Methods for Fluorescence Background Subtraction from Raman
  Spectra

abstract:
  Raman spectroscopy has attracted interest as a non-invasive optical technique
to study the composition and structure of a wide range of materials at the
microscopic level. The intrinsic fluorescence background can be orders of
magnitude stronger than the Raman scattering and so background removal is one
of the foremost challenges for quantitative analysis of Raman spectra in many
samples. A range of methods anchored in instrumental and computational
programming approaches have been proposed for removing fluorescence background
signals. An enhanced adaptive weighting scheme for automated fluorescence
removal is reported, applicable to both polynomial fitting and penalised least
squares approaches. Analysis of the background fitting results for ensembles of
simulated spectra suggests that the method is robust and reliable, and can
significantly improve the background fit over the range of signal, shot-noise
and background parameters tested, while reducing the subjective nature of the
process. The method was also illustrated by application to experimental data
generated from aqueous solutions of bulk protein fibrinogen mixed with dextran.


title: Galaxy redshift surveys with sparse sampling

abstract:
  Survey observations of the three-dimensional locations of galaxies are a
powerful approach to measure the distribution of matter in the universe, which
can be used to learn about the nature of dark energy, physics of inflation,
neutrino masses, etc. A competitive survey, however, requires a large volume
(e.g., Vsurvey is roughly 10 Gpc3) to be covered, and thus tends to be
expensive. A "sparse sampling" method offers a more affordable solution to this
problem: within a survey footprint covering a given survey volume, Vsurvey, we
observe only a fraction of the volume. The distribution of observed regions
should be chosen such that their separation is smaller than the length scale
corresponding to the wavenumber of interest. Then one can recover the power
spectrum of galaxies with precision expected for a survey covering a volume of
Vsurvey (rather than the volume of the sum of observed regions) with the number
density of galaxies given by the total number of observed galaxies divided by
Vsurvey (rather than the number density of galaxies within an observed region).
We find that regularly-spaced sampling yields an unbiased power spectrum with
no window function effect, and deviations from regularly-spaced sampling, which
are unavoidable in realistic surveys, introduce calculable window function
effects and increase the uncertainties of the recovered power spectrum. While
we discuss the sparse sampling method within the context of the forthcoming
Hobby-Eberly Telescope Dark Energy Experiment, the method is general and can be
applied to other galaxy surveys.


title: Approximating dependent rare events

abstract:
  In this paper we give a historical account of the development of Poisson
approximation using Stein's method and present some of the main results. We
give two recent applications, one on maximal arithmetic progressions and the
other on bootstrap percolation. We also discuss generalisations to compound
Poisson approximation, Poisson process approximation and multivariate Poisson
approximation, and state a few open problems.


title: Black hole wind speeds and the M-sigma relation

abstract:
  We derive an M_bh-sigma relation between supermassive black hole mass and
stellar velocity dispersion in galaxy bulges, that results from self-regulated,
energy-conserving feedback. The relation is of the form M_bh v_w \propto
sigma^5, where v_w is the velocity of the wind driven by the black hole. We
take a sample of quiescent early-type galaxies and bulges with measured black
hole masses and velocity dispersions and use our model to infer the wind speeds
they would have had during an active phase. This approach, in effect,
translates the scatter in the observed M_bh-sigma relation into a distribution
of v_w. There are some remarkable similarities between the distribution of
black hole wind speeds that we obtain and the distributions of outflow speeds
observed in local AGN, including a comparable median of v_w = 0.035 c.


title: Anisotropy in solid inflation

abstract:
  In the model of solid / elastic inflation, inflation is driven by a source
that has the field theoretical description of a solid. To allow for prolonged
slow roll inflation, the solid needs to be extremely insensitive to the spatial
expansion. We point out that, because of this property, the solid is also
rather inefficient in erasing anisotropic deformations of the geometry. This
allows for a prolonged inflationary anisotropic solution, providing the first
example with standard gravity and scalar fields only which evades the
conditions of the so called cosmic no-hair conjecture. We compute the curvature
perturbations on the anisotropic solution, and the corresponding
phenomenological bound on the anisotropy. Finally, we discuss the analogy
between this model and the f (phi) F^2 model, which also allows for anisotropic
inflation thanks to a suitable coupling between the inflaton phi and a vector
field. We remark that the bispectrum of the curvature perturbations in solid
inflation is enhanced in the squeezed limit and presents a nontrivial angular
dependence, as had previously been found for the f (phi) F^2 model.


title:
Hierarchical Parallel Matrix Multiplication on Large-Scale Distributed
  Memory Platforms

abstract:
  Matrix multiplication is a very important computation kernel both in its own
right as a building block of many scientific applications and as a popular
representative for other scientific applications. Cannon algorithm which dates
back to 1969 was the first efficient algorithm for parallel matrix
multiplication providing theoretically optimal communication cost. However this
algorithm requires a square number of processors. In the mid 1990s, the SUMMA
algorithm was introduced. SUMMA overcomes the shortcomings of Cannon algorithm
as it can be used on a non-square number of processors as well. Since then the
number of processors in HPC platforms has increased by two orders of magnitude
making the contribution of communication in the overall execution time more
significant. Therefore, the state of the art parallel matrix multiplication
algorithms should be revisited to reduce the communication cost further. This
paper introduces a new parallel matrix multiplication algorithm, Hierarchical
SUMMA (HSUMMA), which is a redesign of SUMMA. Our algorithm reduces the
communication cost of SUMMA by introducing a two-level virtual hierarchy into
the two-dimensional arrangement of processors. Experiments on an IBM BlueGene-P
demonstrate the reduction of communication cost up to 2.08 times on 2048 cores
and up to 5.89 times on 16384 cores.


title: Transfer and characteristic idempotents for saturated fusion systems

abstract:
  We construct a well-behaved transfer map from the p-local Burnside ring of
the underlying p-group S to the p-local Burnside ring of a saturated fusion
system F. Using this transfer map, we give new results on the characteristic
idempotent of F -- the unique idempotent in the p-local double Burnside ring of
S satisfying properties of Linckelmann and Webb. We describe this idempotent
explicitly both in terms of fixed points and as a linear combination of
transitive bisets. Additionally, using fixed points we determine the map for
Burnside rings given by multiplication with the characteristic idempotent, and
show that this is the transfer map previously constructed. Applying these
results, we show that for every saturated fusion system the ring generated by
all (not necessarily idempotent) characteristic elements in the p-local double
Burnside ring is isomorphic as rings to the p-local "single" Burnside ring of
the fusion system, and we disprove a conjecture by Park-Ragnarsson-Stancu on
the composition product of fusion systems.


title: On a convolution series attached to a Siegel Hecke cusp form of degree 2

abstract:
  We prove that the "naive" convolution Dirichlet series D_2(s) attached to a
degree 2 Siegel Hecke cusp form F, has a pole at s=1. As an application, we
write down the asymptotic formula for the partial sums of the squares of the
eigenvalues of $F$ with an explicit error term. Further, as a corollary, we are
able to show that the abscissa of absolute convergence of the (normalized)
spinor zeta function attached to F is s = 1.


title:
Extremal unicyclic graphs with respect to additively weighted Harary
  index

abstract:
  In this paper we define cycle-star graph CSk,n-k to be a graph on n vertices
consisting of the cycle of length k and n-k leafs appended to the same vertex
of the cycle. Also, we define cycle-path graph CPk,n-k to be a graph on n
vertices consisting of the cycle of length k and of path on n-k vertices whose
one end is linked to a vertex on a cycle. We establish that cycle-star graph
CS3,n-3 is the only maximal graph with respect to additively weighted Harary
index among all unicyclic graphs on n vertices, while cycle-path graph CP3,n-3
is the only minimal unicyclic graph (here n must be at least 5). The values of
additively weighted Harary index for extremal unicyclic graphs are established,
so these values are the upper and the lower bound for the value of additively
weighted Harary index on the class of unicyclic graphs on n vertices.


title:
Thermoelastic study of nanolayered structures using time-resolved x-ray
  diffraction at high repetition rate

abstract:
  We investigate the thermoelastic response of a nanolayered sample composed of
a metallic SrRuO3 (SRO) electrode sandwiched between a ferroelectric
Pb(Zr0.2Ti0.8)O3 (PZT) film with negative thermal expansion and a SrTiO3
substrate. SRO is rapidly heated by fs-laser pulses with 208 kHz repetition
rate. Diffraction of x-ray pulses derived from a synchrotron measures the
transient out-of-plane lattice constant c of all three materials simultaneously
from 120 ps to 5 mus with a relative accuracy up to Delta c/c = 10^-6. The
in-plane propagation of sound is essential for understanding the delayed out of
plane expansion.


title:
Second-Order Asymptotics of Conversions of Distributions and Entangled
  States Based on Rayleigh-Normal Probability Distributions

abstract:
  We discuss the asymptotic behavior of conversions between two independent and
identical distributions up to the second-order conversion rate when the
conversion is produced by a deterministic function from the input probability
space to the output probability space. To derive the second-order conversion
rate, we introduce new probability distributions named Rayleigh-normal
distributions. The family of Rayleigh-normal distributions includes a Rayleigh
distribution and coincides with the standard normal distribution in the limit
case. Using this family of probability distributions, we represent the
asymptotic second-order rates for the distribution conversion. As an
application, we also consider the asymptotic behavior of conversions between
the multiple copies of two pure entangled states in quantum systems when only
local operations and classical communications (LOCC) are allowed. This problem
contains entanglement concentration, entanglement dilution and a kind of
cloning problem with LOCC restriction as special cases.


title:
Noise-Induced Bistable States and Their Mean Switching Time in Foraging
  Colonies

abstract:
  We investigate a type of bistability where noise not only causes transitions
between stable states, but also constructs the states themselves. We focus on
the experimentally well-studied system of ants choosing between two food
sources to illustrate the essential points, but the ideas are more general. The
mean time for switching between the two bistable states of the system is
calculated. This suggests a procedure for estimating, in a real system, the
critical population size above which bistability ceases to occur.


title: Cosmological Tests of the Disformal Coupling to Radiation

abstract:
  Light scalar fields can naturally couple disformally to Standard Model fields
without giving rise to the unacceptably large fifth forces usually associated
with light scalars. We show that these scalar fields can still be studied and
constrained through their interaction with photons, and focus particularly on
changes to the Cosmic Microwave Background spectral distortions and violations
of the distance duality relation. We then specialise our constraints to scalars
which could play the role of axionic quintessence.


title:
Heavy quark production and gluon saturation in double parton scattering
  at LHC

abstract:
  The production of $c\bar{c}c\bar{c}$, $b\bar{b}b\bar{b}$ and
$c\bar{c}b\bar{b}$ pairs considering double parton scattering at LHC energies
is investigated. We estimate the contribution of saturation effects to the
different final states and predict the energy dependence of the cross sections.
Moreover, we estimate the ratio between the double and single parton scattering
cross sections for the full rapidity range of the LHC and for the rapidity
range of the LHCb experiment. For the full rapidity range we confirm a previous
prediction, namely that for charm production the double parton scattering
contribution becomes comparable with the single parton scattering one at LHC
energies. We also demonstrate that this result remains valid when one
introduces saturation effects in the calculations. Finally we show that the
production of $c\bar{c}b\bar{b}$ contributes significantly to bottom
production. For the LHCb kinematical range the ratio is strongly reduced.


title:
Magnetic anisotropy and lattice dynamics in FeAs studied by M\"ossbauer
  spectroscopy

abstract:
  Iron mono-arsenide in the powder form has been investigated by transmission
57Fe Moessbauer spectroscopy in the temperature range 4.2 - 1000 K. Additional
spectra have been obtained at 20 K and 100 K applying external magnetic field
of 7 T. It was found that the spin spiral propagating along the c-axis leads to
the complex variation of the hyperfine magnetic field amplitude with the spin
orientation varying in the a-b plane. The magnitude of the hyperfine field
pointing in the direction of the local magnetic moment depends on the
orientation of this moment in the a-b plane. Patterns are vastly different for
iron located in the [0 k 0] positions and for iron in the [0 k+1/2 0] positions
within the orthorhombic cell set to the Pnma symmetry. Lattice softens upon
transition to the paramagnetic state at 69.2 K primarily in the a-c plane as
seen by iron atoms. This effect is quite large considering lack of the
structural transition. Two previously mentioned iron sites are discernible in
the paramagnetic region till 300 K by different electron densities on the iron
nuclei. The anisotropy of the iron vibrations developed at the transition to
the paramagnetic state increases with the temperature in accordance with the
harmonic approximation, albeit tends to saturation at high temperatures
indicating gradual onset of the quasi-harmonic conditions. It seems that
neither hyperfine fields nor magnetic moments are correct order parameters in
light of the determined static critical exponents. Sample starts to loose
arsenic at about 1000 K and under vacuum.


title: Dark matter searches with cosmic antideuterons: status and perspectives

abstract:
  The search for antideuterons in cosmic rays has been proposed as a promising
channel for dark matter indirect detection, especially for dark matter
particles with a low or intermediate mass. With the current operational phase
of the AMS-02 experiment and the ongoing development of a future dedicated
experiment, the General Antiparticle Spectrometer (GAPS), there are exciting
prospects for a dark matter detection in the near future. In this paper we
develop a detailed and complete re-analysis of the cosmic-ray antideuteron
signal, by discussing the main relevant issues related to antideuteron
production and propagation through the interstellar medium and the heliosphere.
In particular, we first critically revisit the coalescence mechanism for
antideuteron production in dark matter annihilation processes. Then, since
antideuteron searches have their best prospects of detection at low kinetic
energies where the effect of the solar wind and magnetic field are most
relevant, we address the impact of solar modulation modeling on the
antideuteron flux at the Earth by developing a full numerical 4D solution of
cosmic rays transport in the heliosphere. We finally use these improved
predictions to provide updated estimates of the reaching capabilities for
AMS-02 and GAPS, compatible with the current constraints imposed by the
antiprotons measurements of PAMELA. After the antiproton bound is applied,
prospects of detection of up to about 15 events in GAPS LDB+ and AMS-02
missions are found, depending on the dark matter mass, annihilation rate and
production channel from one side, and on the coalescence process, galactic and
solar transport parameters on the other.


title:
High resolution probe of coherence in low-energy charge exchange
  collisions with oriented targets

abstract:
  The trapping lasers of a magneto-optical trap (MOT) are used to bring Rb
atoms into well defined oriented states. Coupled to recoil-ion momentum
spectroscopy (RIMS), this yields a unique MOTRIMS setup which is able to probe
scattering dynamics, including their coherence features, with unprecedented
resolution. This technique is applied to the low-energy charge exchange
processes Na$^+$+Rb($5p_{\pm 1}$) $\rightarrow$ Na($3p,4s$)+Rb$^+$. The
measurements reveal detailed features of the collisional interaction which are
employed to improve the theoretical description. All of this enables to gauge
the reliability of intuitive pictures predicting the most likely capture
transitions.


title: Dark Matter directional detection with MIMAC

abstract:
  Directional detection is a promising direct Dark Matter (DM) search strategy.
The angular distribution of the nuclear recoil tracks from WIMP events should
present an anisotropy in galactic coordinates. This strategy requires both a
measurement of the recoil energy with a threshold of about 5 keV and 3D recoil
tracks down to few millimeters.
  The MIMAC project, based on a \textmu-TPC matrix, with $CF_4$ and $CHF_3$, is
being developed. In June 2012, a bi-chamber prototype was installed at the LSM
(Laboratoire Souterrain de Modane). A preliminary analysis of the first four
months data taking allowed, for the first time, the observation of recoils from
the $\mathrm{^{222}Rn}$ progeny.


title:
Physical-layer encryption on the public internet: a stochastic approach
  to the Kish-Sethuraman cipher

abstract:
  While information-theoretic security is often associated with the one-time
pad and quantum key distribution, noisy transport media leave room for
classical techniques and even covert operation. Transit times across the public
internet exhibit a degree of randomness, and cannot be determined noiselessly
by an eavesdropper. We demonstrate the use of these measurements for
information-theoretically secure communication over the public internet.


title:
Quantization of Poisson manifolds from the integrability of the modular
  function

abstract:
  We discuss a framework for quantizing a Poisson manifold via the quantization
of its symplectic groupoid, that combines the tools of geometric quantization
with the results of Renault's theory of groupoid C*-algebras. This setting
allows very singular polarizations. In particular we consider the case when the
modular function is "multiplicatively integrable", i.e. when the space of
leaves of the polarization inherits a groupoid structure. If suitable
regularity conditions are satisfied, then one can define the quantum algebra as
the convolution algebra of the subgroupoid of leaves satisfying the
Bohr-Sommerfeld conditions. We apply this procedure to the case of a family of
Poisson structures on CP_n, seen as Poisson homogeneous spaces of the standard
Poisson-Lie group SU(n+1). We show that a bihamiltoniam system on CP_n defines
a multiplicative integrable model on the symplectic groupoid; we compute the
Bohr-Sommerfeld groupoid and show that it satisfies the needed properties for
applying Renault theory. We recover and extend Sheu's description of quantum
homogeneous spaces as groupoid C*-algebras.


title: Dynamical analysis of an optical rocking ratchet: Theory and experiment

abstract:
  A thorough analysis of the dynamics in a deterministic optical rocking
ratchet (introduced in A. V. Arzola et al., Phys. Rev. Lett. 106, 168104
(2011)) and a comparison with experimental results are presented. The studied
system consists of a microscopic particle interacting with a periodic and
asymmetric light pattern, which is driven away from equilibrium by means of an
unbiased time- periodic external force. It is shown that the asymmetry of the
effective optical potential depends on the relative size of the particle with
respect to the spatial period, and this is analyzed as an effective mechanism
for particle fractionation. The necessary conditions to obtain current
reversals in the deterministic regime are discussed in detail.


title:
Incongruity of the unified scheme with a 3CRR-like equatorial
  strong-source sample

abstract:
  We examine the consistency of the unified scheme of the powerful
extragalactic radio sources with the 408 MHz BRL sample from the equatorial sky
region, selected at the same flux-density level as the 3CRR sample. We find
that, unlike in the 3CRR sample, a foreshortening in the observed sizes of
quasars, expected from the orientation-based unified scheme model, is not seen
in the BRL sample, at least in different redshift bins up to z~1. Even the
quasar fraction in individual redshift bins up to z~1 does not match with that
expected from the unified scheme, where radio galaxies and quasars are supposed
to belong to a common parent population at all redshifts. This not only casts
strong doubts on the unified scheme, but also throws up an intriguing result
that in a sample selected from the equatorial sky region, using almost the same
criteria as in the 3CRR sample from the northern hemisphere, the relative
distribution of radio galaxies and quasars differs qualitatively from the 3CRR
sample.


title: Space-time structure of polynomiality and positivity for GPDs

abstract:
  We study the space-time structure of polynomiality and positivity---the most
important properties which are inherent to the generalized parton distributions
(GPDs). In this connection, we re-examine the issue of the time- and normal-
ordering in the operator definition of GPDs. We demonstrate that the
contribution of the anti-commutator matrix element in the collinear kinematics,
which was previously argued to vanish, has to be added in order to satisfy the
polynomiality condition. Furthermore, we schematically show that a new
contribution due to the anti-commutator modifies likewise the so-called
positivity constraint, i.e., the Cauchy-Bunyakovsky-Schwarz inequality, which
is another important feature of the GPDs.


title:
On the Godsil -- Higman necessary condition for equitable partitions of
  association schemes

abstract:
  In the monograph 'Association schemes', C. Godsil derived a necessary
condition for equitable partitions of association schemes and noticed that it
could be used to show that certain equitable partitions do not exist. In this
short note, we show that, in fact, this condition is not stronger than the
well-known Lloyd theorem.


title: New Suns in the Cosmos?

abstract:
  The present work reports on the discovery of three stars that we have
identified to be rotating Sun-like stars, based on rotational modulation
signatures inferred from light curves from the CoRoT mission's Public Archives.
In our analysis, we performed an initial selection based on rotation period and
position in the Period--$T_{\rm eff}$ diagram. This revealed that the stars
CoRoT IDs 100746852, 102709980, and 105693572 provide potentially good matches
to the Sun with similar rotation period. To refine our analysis, we applied a
novel procedure, taking into account the fluctuations of the features
associated to photometric modulation at different time intervals and the
fractality traces that are present in the light curves of the Sun and of these
"New Sun" candidates alike. In this sense, we computed the so-called Hurst
exponent for the referred stars, for a sample of fourteen CoRoT stars with sub-
and super-solar rotational periods, and for the Sun, itself, in its active and
quiet phases. We found that the Hurst exponent can provide a strong
discriminant of Sun-like behavior, going beyond what can be achieved with
solely the rotation period itself. In particular, we find that CoRoT ID
105693572 is the star that most closely matches the solar rotation properties,
as far as the latter's imprints on light curve behavior is concerned. The stars
CoRoT IDs 100746852 and 102709980 have significant smaller Hurst exponents than
the Sun, notwithstanding their similarity in rotation periods.


title:
Optimal control of light propagation through multiple-scattering media
  in the presence of noise

abstract:
  We study the control of coherent light propagation through
multiple-scattering media in the presence of measurement noise. In our
experiments, we use a two-step optimization procedure to find the optimal
incident wavefront. We conclude that the degree of optimal control of coherent
light propagation through a multiple-scattering medium is only determined by
the number of photoelectrons detected per single speckle spot. The prediction
of our model agrees well with the experimental results. Our results offer
opportunities for imaging applications through scattering media such as
biological tissue in the shot noise limit.


title: QCD Sum Rule Study for a Possible Charmed Pentaquark \Theta c(3250)

abstract:
  We use QCD sum rules to study the possible existence of a \Theta c(3250)
charmed pentaquark. We consider the contributions of condensates up to
dimension-10 and work at leading order in \alpha_s. We obtain m(\Theta c) =
(3.21 +/- 0.13) GeV, compatible with the mass of the structure seen by BaBar
Collaboration in the decay channel B- -> p- \Sigma c++ pi- pi-. The proposed
state is compatible with a previous proposed pentaquark state in the
anti-charmed sector.


title:
Snowmass whitepaper: Exploring natural SUSY via direct and indirect
  detection of higgsino-like WIMPs

abstract:
  Supersymmetric models with low electroweak fine-tuning contain light
higgsinos with mass not too far from m_h\simeq 125 GeV, while other sparticles
can be much heavier. In the R-parity conserving MSSM, the lightest neutralino
is then a higgsino-like WIMP (albeit with non-negligible gaugino components),
with thermal relic density well below measured values. This leaves room for
axions (or other, perhaps not as well motivated, stable particles) to function
as co-dark matter particles. The local WIMP abundance is then expected to be
below standard estimates, and direct and indirect detection rates must be
accordingly rescaled. We calculate rescaled direct and indirect higgsino-like
WIMP detection rates in SUSY models that fulfil the electroweak naturalness
condition. In spite of the rescaling, we find that ton-scale noble liquid
detectors can probe the entire higgsino-like WIMP parameter space, so that
these experiments should either discover WIMPs or exclude the concept of
electroweak naturalness in R-parity conserving natural SUSY models. Prospects
for spin-dependent or indirect detection are more limited due in part to the
rescaling effect.


title:
Orbital-selective superconductivity, gap anisotropy and spin resonance
  excitations in a multiorbital t-J1-J2 model for iron pnictides

abstract:
  We study the orbital-dependent superconducting pairing in a five-orbital
t-J1-J2 model for iron pnictides. Depending on the orbital selectivity of
electron correlations and the orbital characters along the Fermi surface, the
superconducting gap in an A_{1g} pairing state may exhibit anisotropy. This
anisotropy varies with the degree of J1-J2 magnetic frustration. We have also
calculated the dynamical spin susceptibility in the superconducting state. The
frequency dependence of the susceptibility at the antiferromagnetic wavevector
(\pi,0) shows a resonance, whose width is enhanced by the orbital dependence of
the superconducting gap; when the latter is sufficiently strong, the resonance
peak may be split into two. We discuss the implications of our results on the
recent angle-resolved photoemission and neutron-scattering measurements in
several superconducting iron pnictides.


title:
Charged Hadron Multiplicity Distribution at Relativistic Heavy Ion
  Colliders

abstract:
  The present article reviews facts and problems concerning charge hadron
production in high energy collisions. Main emphasis is laid on the qualitative
and quantitative description of general characteristics and properties observed
for charged hadrons produced in such high energy collisions. Various features
of available experimental data e.g., the variations of charged hadron
multiplicity and pseudo-rapidity density with the mass number of colliding
nuclei, center-of-mass energies and the collision centrality obtained from
heavy-ion collider experiments are interpreted in the context of various
theoretical concepts and their implications. Finally, several important scaling
features observed in the measurements mainly at RHIC and LHC experiments are
highlighted in the view of these models to draw some insight regarding the
particle production mechanism in heavy-ion collisions.


title:
XMM-Newton observations of the Galactic Centre Region - II: The soft
  thermal emission

abstract:
  We have extended our earlier study (Heard & Warwick 2013, Paper I) of the
X-ray emission emanating from the central 100 pc x 100 pc region of our Galaxy
to an investigation of several features prominent in the soft X-ray (2-4.5 keV)
band. We focus on three specific structures: a putative bipolar outflow from
the vicinity of Sgr A*; a high surface brightness region located roughly 12
arcmin to the north-east of Sgr A*; and a lower surface-brightness extended
loop feature seen to the south of Sgr A*. We show that all three structures are
thermal in nature and have similar temperatures (kT ~ 1 keV). The inferred
X-ray luminosities lie in the range (2 - 10) x 10^34 erg s^-1. In the case of
the bipolar feature we suggest that the hot plasma is produced by the
shock-heating of the winds from massive stars within the Central Cluster,
possibly collimated by the Circumnuclear Disc. Alternatively the outflow may be
driven by outbursts on Sgr A*, which follow tidal disruption events occurring
at a rate of roughly 1 every 4000 yr. The north-east enhancement is centred on
a candidate PWN which has a relatively hard non-thermal X-ray spectrum. We
suggest that the coincident soft-thermal emission traces the core of a new
thermal-composite supernova remnant, designated as SNR G0.13-0.12. There is no
clear evidence for an associated radio shell but such a feature may be masked
by the bright emission of the nearby Radio Arc and other filamentary
structures. SNR G0.13-0.12 is very likely interacting with the nearby molecular
cloud, G0.11-0.11, and linked to the Fermi source, 2FGL J1746.4-2851c. Finally
we explore a previous suggestion that the elliptically-shaped X-ray loop to the
south of Sgr A*, of maximum extent ~45 pc, represents the shell of a
superbubble located in the GC region. Although plausible, the interpretation of
this feature in terms a coherent physical structure awaits confirmation.


title:
Dynamical Exchange Interaction From Time-Dependent Spin Density
  Functional Theory

abstract:
  We report on {\it ab initio} time-dependent spin dynamics simulations for a
two-center magnetic molecular complex based on time-dependent non-collinear
spin density functional theory. In particular, we discuss how the dynamical
behavior of the {\it ab initio} spin-density in the time-domain can be mapped
onto a model Hamiltonian based on the classical Heisenberg spin-spin
interaction $J\vcr{S}_1\cdot \vcr{S}_2$. By analyzing individual localized-spin
trajectories, extracted from the spin-density evolution, we demonstrate a novel
method for evaluating the effective Heisenberg exchange coupling constant, $J$,
from first principles simulations. We find that $J$, extracted in such a new
dynamical way, agrees quantitatively to that calculated by the standard density
functional theory broken-symmetry scheme.

categories: cond-mat.other cond-mat.mes-hall cond-mat.mtrl-sci physics.atm-clus quant-ph


title: Reichenbach's Transcendental Probability

abstract:
  The aim of this article is twofold. First, we shall review and analyse the
Neo-Kantian justification for the application of probabilistic concepts in
physics that was defended by Hans Reichenbach early in his career, notably in
his dissertation of 1916. At first sight this Kantian approach seems to
contrast sharply with Reichenbach's later logical positivist, frequentist
viewpoint. But, and this is our second goal, we shall attempt to show that
there is an underlying continuity in Reichenbach's thought: typical features of
his early Kantian conceptions can still be recognized in his later work.


title:
Thermoelectric effects and the asymmetry of the current-voltage
  characteristics of metallic point contacts

abstract:
  An asymmetry as a function of the direction of current flow is observed in
the current-voltage characteristic (CVC) and its first and second derivatives
for point heterocontacts between pure metals {Cu, Ni, Fe) as well as between
these metals and dilute alloys (CuFe, CuMn). It is shown that the observed
asymmetry is caused by thermoelectrical phenomena (Seebeck, Peltier, and
Thompson effects), observed when the temperature inside the contact differs
from the temperature of the bath. In the low energy range (less than or of the
order of the Debye energy) the asymmetry of the CVC is affected mainly by the
Seebeck effect, while at high energies and for larger contacts (lower
resistance) the contributions of all noted effects are of the same order of
magnitude. A technique is proposed for determining the temperature of a
heterocontact by measuring the CVC in two polarities. It is established that in
the intermediate (between the diffusion and ballistic) state of flight of the
electrons through the constriction the temperature of the heterocontact
increases linearly with the voltage on it, and all the more rapidly the larger
the contact and the more impurity in it.


title:
The High Time Resolution Universe Pulsar Survey VIII: The Galactic
  millisecond pulsar population

abstract:
  We have used millisecond pulsars (MSPs) from the southern High Time
Resolution Universe (HTRU) intermediate latitude survey area to simulate the
distribution and total population of MSPs in the Galaxy. Our model makes use of
the scale factor method, which estimates the ratio of the total number of MSPs
in the Galaxy to the known sample. Using our best fit value for the z-height,
z=500 pc, we find an underlying population of MSPs of 8.3(\pm 4.2)*10^4 sources
down to a limiting luminosity of L_min=0.1 mJy kpc^2 and a luminosity
distribution with a steep slope of d\log N/d\log L = -1.45(\pm 0.14). However,
at the low end of the luminosity distribution, the uncertainties introduced by
small number statistics are large. By omitting very low luminosity pulsars, we
find a Galactic population above L_min=0.2 mJy kpc^2 of only 3.0(\pm 0.7)*10^4
MSPs. We have also simulated pulsars with periods shorter than any known MSP,
and estimate the maximum number of sub-MSPs in the Galaxy to be 7.8(\pm
5.0)*10^4 pulsars at L=0.1 mJy kpc^2. In addition, we estimate that the high
and low latitude parts of the southern HTRU survey will detect 68 and 42 MSPs
respectively, including 78 new discoveries. Pulsar luminosity, and hence flux
density, is an important input parameter in the model. Some of the published
flux densities for the pulsars in our sample do not agree with the observed
flux densities from our data set, and we have instead calculated average
luminosities from archival data from the Parkes Telescope. We found many
luminosities to be very different than their catalogue values, leading to very
different population estimates. Large variations in flux density highlight the
importance of including scintillation effects in MSP population studies.


title: Precision-guaranteed quantum tomography

abstract:
  Quantum state tomography is the standard tool in current experiments for
verifying that a state prepared in the lab is close to an ideal target state,
but up to now there were no rigorous methods for evaluating the precision of
the state preparation in tomographic experiments. We propose a new estimator
for quantum state tomography, and prove that the (always physical) estimates
will be close to the true prepared state with high probability. We derive an
explicit formula for evaluating how high the probability is for an arbitrary
finite-dimensional system and explicitly give the one- and two-qubit cases as
examples. This formula applies for any informationally complete sets of
measurements, arbitrary finite number of data sets, and general loss functions
including the infidelity, the Hilbert-Schmidt, and the trace distances. Using
the formula, we can evaluate not only the difference between the estimated and
prepared states, but also the difference between the prepared and target
states. This is the first result directly applicable to the problem of
evaluating the precision of estimation and preparation in quantum tomographic
experiments.


title:
Elliptic Euler-Poisson-Darboux equation, critical points and integrable
  systems

abstract:
  Structure and properties of families of critical points for classes of
functions $W(z,\bar{z})$ obeying the elliptic Euler-Poisson-Darboux equation
$E(1/2,1/2)$ are studied. General variational and differential equations
governing the dependence of critical points in variational (deformation)
parameters are found. Explicit examples of the corresponding integrable
quasi-linear differential systems and hierarchies are presented There are the
extended dispersionless Toda/nonlinear Schr\"{o}dinger hierarchies, the
"inverse" hierarchy and equations associated with the real-analytic Eisenstein
series $E(\beta,\bar{{\beta}};1/2)$among them. Specific bi-Hamiltonian
structure of these equations is also discussed.


title: Gravity Effects on Information Filtering and Network Evolving

abstract:
  In this paper, based on the gravity principle of classical physics, we
propose a tunable gravity-based model, which considers tag usage pattern to
weigh both the mass and distance of network nodes. We then apply this model in
solving the problems of information filtering and network evolving.
Experimental results on two real-world data sets, \emph{Del.icio.us} and
\emph{MovieLens}, show that it can not only enhance the algorithmic
performance, but can also better characterize the properties of real networks.
This work may shed some light on the in-depth understanding of the effect of
gravity model.


title: Commability and focal locally compact groups

abstract:
  We introduce the notion of commability between locally compact groups, namely
the equivalence relation generated by cocompact inclusions and quotients by
compact normal subgroups. We give a classification of focal hyperbolic locally
compact groups up to commability. In the mixed case, it involves a real
parameter, which is shown to be a quasi-isometry invariant.


title:
The Star Formation History of the Solar Neighbourhood from the White
  Dwarf Luminosity Function

abstract:
  The termination in the white dwarf luminosity function is a standard
diagnostic tool for measuring the total age of nearby stellar populations. In
this paper, an algorithm is presented for inverting the full white dwarf
luminosity function to obtain a maximum likelihood estimate of the time varying
star formation rate of the host stellar population. Tests with synthetic data
demonstrate that the algorithm converges over a wide class of underlying star
formation rate forms. The algorithm successfully estimates the moving average
star formation rate as a function of lookback time in the presence of realistic
measurement noise, though suffers from degeneracies around discontinuities in
the underlying star formation rate. The inversion results are most sensitive to
the choice of white dwarf cooling models, with the models produced by different
groups giving quite different results. The results are relatively insensitive
to the progenitor metallicity, initial mass function, initial-final mass
relation and ratio of H/He atmosphere white dwarfs. Application to two
independent determinations of the Solar neighbourhood white dwarf luminosity
function gives similar results. The star formation rate has a bimodal form,
with broad peaks at 2-3 Gyr and 7-9 Gyr in the past, separated by a significant
lull of magnitude 30-90% depending on choice of cooling models. The onset of
star formation occurs around 8-10 Gyr ago. The total integrated star formation
rate is ~0.014 stars/pc3 in the Solar neighbourhood, for stars more massive
than 0.6M_{solar}.


title:
Evidence for A Two-dimensional Quantum Wigner Solid in Zero Magnetic
  Field

abstract:
  We report the first experimental observation of a characteristic nonlinear
threshold behavior from dc dynamical response as an evidence for a Wigner
crystallization in high-purity GaAs 2D hole systems in zero magnetic field. The
system under increasing current drive exhibits voltage oscillations with
negative differential resistance. They confirm the coexistence of a moving
crystal along with striped edge states as observed for electrons on helium
surfaces. However, the threshold is well below the typical classical levels due
to a different pinning and depinning mechanism that is possibly related to a
quantum process.


title: Bialgebra of specified graphs and external structures

abstract:
  We construct a Hopf algebra structure on the space of specified Feynman
graphs of a quantum field theory. We introduce a convolution product and a
semigroup of characters of this Hopf algebra with values in some suitable
commutative algebra taking momenta into account. We then implement the
renormalization described by A. Connes and D. Kreimer and the Birkhoff
decomposition for two renormalization schemes: the minimal subtraction scheme
and the Taylor expansion scheme.


title: T-duality for circle bundles via noncommutative geometry

abstract:
  Recently Baraglia showed how topological T-duality can be extended to apply
not only to principal circle bundles, but also to non-principal circle bundles.
We show that his results can also be recovered via two other methods: the
homotopy-theoretic approach of Bunke and Schick, and the noncommutative
geometry approach which we previously used for principal torus bundles. This
work has several interesting byproducts, including a study of the K-theory of
crossed products by Isom(R), the universal cover of O(2), and some interesting
facts about equivariant K-theory for Z/2. In the final section of this paper,
these results are extended to the case of bundles with singular fibers, or in
other words, non-free O(2)-actions.


title: Review of the Multimessenger Working Group at UHECR-2012

abstract:
  The current status of searches for ultra-high energy neutrinos and photons
using air showers is reviewed. Regarding both physics and observational
aspects, possible future research directions are indicated.


title:
Effects of quasiparticle tunneling in a circuit-QED realization of a
  strongly driven two-level system

abstract:
  We experimentally and theoretically study the frequency shift of a driven
cavity coupled to a superconducting charge qubit. In addition to previous
studies, we here also consider drive strengths large enough to energetically
allow for quasiparticle creation. Quasiparticle tunneling leads to the
inclusion of more than two charge states in the dynamics. To explain the
observed effects, we develop a master equation for the microwave dressed charge
states, including quasiparticle tunneling. A bimodal behavior of the frequency
shift as a function of gate voltage can be used for sensitive charge detection.
However, at weak drives the charge sensitivity is significantly reduced by
non-equilibrium quasiparticles, which induce transitions to a non-sensitive
state. Unexpectedly, at high enough drives, quasiparticle tunneling enables a
very fast relaxation channel to the sensitive state. In this regime, the charge
sensitivity is thus robust against externally injected quasiparticles and the
desired dynamics prevail over a broad range of temperatures. We find very good
agreement between theory and experiment over a wide range of drive strengths
and temperatures.


title:
Hadronic Freeze-Out in A+A Collisions meets the Lattice QCD
  Parton-Hadron Transition Line

abstract:
  We analyze hadrochemical freeze-out in central Pb+Pb collisions at CERN SPS
and LHC energies. Employing the UrQMD hybrid transport model we study the
effects of the final hadron/resonance expansion phase on the hadron
multiplicities established at hadronization. The bulk meson yields freeze out
directly at hadronization whereas the baryon-antibaryon sector is subject to
significant alterations, due to annihilation and regeneration processes. We
quantify the latter changes by survival factors for each species which are
applied to modify the statistical model predictions for the data. The modified
SM analysis recovers the hadronization points, which coincide with the recent
lattice QCD predictions of the parton-hadron transition line at finite
baryochemical potential.


title:
COW test of the weak equivalence principle: A low-energy window to look
  into the noncommutative structure of space-time?

abstract:
  We construct the quantum mechanical model of the COW experiment assuming that
the underlying space time has a granular structure, described by a canonical
noncommutative algebra of coordinates $x^{\mu}$. The time-space sector of the
algebra is shown to add a mass-dependent contribution to the gravitational
acceleration felt by neutron deBrogli waves measured in a COW experiment. This
makes time-space noncommutativity a potential candidate for an apparent
violation of WEP even if the ratio of the inertial mass $m_{i}$ and
gravitational mass $m_{g}$ is a universal constant. The latest experimental
result based on COW principle is shown to place an upper-bound several orders
of magnitude stronger than the existing one on the time-space noncommutative
parameter. We argue that the evidence of NC structure of space-time may be
found if the COW-type experiment can be repeated with several particle species.

categories: hep-th gr-qc hep-ph physics.atom-ph quant-ph


title: Dynamical zeta functions for Anosov flows via microlocal analysis

abstract:
  The purpose of this paper is to give a short microlocal proof of the
meromorphic continuation of the Ruelle zeta function for C^\infty Anosov flows.
More general results have been recently proved by Giulietti-Liverani-Pollicott
[arXiv:1203.0904] but our approach is different and is based on the study of
the generator on the flow as a semiclassical differential operator.


title: Chern-Weil theory for certain infinite-dimensional Lie groups

abstract:
  Chern-Weil and Chern-Simons theory extend to certain infinite-rank bundles
that appear in mathematical physics. We discuss what is known of the invariant
theory of the corresponding infinite-dimensional Lie groups. We use these
techniques to detect cohomology classes for spaces of maps between manifolds
and for diffeomorphism groups of manifolds.


title: Sorting polarized photons with a single scatterer

abstract:
  Intuitively, light impinging on a spatially symmetric object will be
scattered symmetrically. This intuition can fail at the nanoscale if the
polarization of the incoming light is properly tailored. In fact, it has been
demonstrated that near-field interference can result in the unidirectional
excitation of plasmonic modes using circularly polarized light. Here we show
that linearly-polarized photons impinging on a single spatially-symmetric
scatterer created in a silicon waveguide are guided into a certain direction of
the waveguide depending exclusively on their polarization angle. Reciprocity
implies that the scatterer can also act as a two-input dielectric nanoantenna
radiating two different linear polarizations. Our work broadens the scope of
near-field interference beyond plasmonics, with applications in polarization
(de)multiplexing, unidirectional coupling, directional switching, radiation
polarization control, and polarization-encoded quantum information processing
in photonic integrated circuits.


title: Melting behavior and different bound states in three-stranded DNA models

abstract:
  Thermal denaturation of DNA is often studied with coarse-grained models in
which native sequential base pairing is mimicked by the existence of attractive
interactions only between monomers at the same position along strands (Poland
and Scheraga models). Within this framework, the existence of a three strand
DNA bound state in conditions where a duplex DNA would be in the denaturated
state was recently predicted from a study of three directed polymer models on
simplified hierarchical lattices ($d>2$) and in $1+1$ dimensions. Such
phenomenon which is similar to the Efimov effect in nuclear physics was named
Efimov-DNA. In this paper we study the melting of the three-stranded DNA on a
Sierpinski gasket of dimensions $d<2$ by assigning extra weight factors to fork
openings and closings, to induce a two-strand DNA melting. In such a context we
can find again the existence of the Efimov-DNA-like state but quite
surprisingly we discover also the presence of a different phase, to be called a
mixed state, where the strands are pair-wise bound but without three chain
contacts. Whereas the Efimov DNA turns out to be a crossover near melting, the
mixed phase is a thermodynamic phase.


title: A bad 2-dimensional instance for k-means++

abstract:
  The k-means++ seeding algorithm is one of the most popular algorithms that is
used for finding the initial $k$ centers when using the k-means heuristic. The
algorithm is a simple sampling procedure and can be described as follows:
{quote} Pick the first center randomly from among the given points. For $i >
1$, pick a point to be the $i^{th}$ center with probability proportional to the
square of the Euclidean distance of this point to the previously $(i-1)$ chosen
centers. {quote} The k-means++ seeding algorithm is not only simple and fast
but gives an $O(\log{k})$ approximation in expectation as shown by Arthur and
Vassilvitskii \cite{av07}. There are datasets \cite{av07,adk09} on which this
seeding algorithm gives an approximation factor $\Omega(\log{k})$ in
expectation. However, it is not clear from these results if the algorithm
achieves good approximation factor with reasonably large probability (say
$1/poly(k)$). Brunsch and R\"{o}glin \cite{br11} gave a dataset where the
k-means++ seeding algorithm achieves an approximation ratio of $(2/3 -
\epsilon)\cdot \log{k}$ only with probability that is exponentially small in
$k$. However, this and all other known {\em lower-bound examples}
\cite{av07,adk09} are high dimensional. So, an open problem is to understand
the behavior of the algorithm on low dimensional datasets. In this work, we
give a simple two dimensional dataset on which the seeding algorithm achieves
an approximation ratio $c$ (for some universal constant $c$) only with
probability exponentially small in $k$. This is the first step towards solving
open problems posed by Mahajan et al \cite{mnv12} and by Brunsch and R\"{o}glin
\cite{br11}.


title: Convex Polytopes from Nested Posets

abstract:
  Motivated by the graph associahedron KG, a polytope whose face poset is based
on connected subgraphs of G, we consider the notion of associativity and tubes
on posets. This leads to a new family of simple convex polytopes obtained by
iterated truncations. These generalize graph associahedra and nestohedra, even
encompassing notions of nestings on CW-complexes. However, these poset
associahedra fall in a different category altogether than generalized
permutohedra.


title:
Strain-mediated coupling in a quantum dot-mechanical oscillator hybrid
  system

abstract:
  Recent progress in nanotechnology has allowed to fabricate new hybrid systems
where a single two-level system is coupled to a mechanical nanoresonator. In
such systems the quantum nature of a macroscopic degree of freedom can be
revealed and manipulated. This opens up appealing perspectives for quantum
information technologies, and for the exploration of quantum-classical
boundary. Here we present the experimental realization of a monolithic
solid-state hybrid system governed by material strain: a quantum dot is
embedded within a nanowire featuring discrete mechanical resonances
corresponding to flexural vibration modes. Mechanical vibrations result in a
time-varying strain field that modulates the quantum dot transition energy.
This approach simultaneously offers a large light extraction efficiency and a
large exciton-phonon coupling strength $g_0$. By means of optical and
mechanical spectroscopy, we find that $g_0/2\pi$ is nearly as large as the
mechanical frequency, a criterion which defines the ultra-strong coupling
regime.


title:
Importance of torsion and invariant volumes in Palatini theories of
  gravity

abstract:
  We study the field equations of extensions of General Relativity formulated
within a metric-affine formalism setting torsion to zero (Palatini approach).
We find that different (second-order) dynamical equations arise depending on
whether torsion is set to zero i) a priori or ii) a posteriori, i.e., before or
after considering variations of the action. Considering a generic family of
Ricci-squared theories, we show that in both cases the connection can be
decomposed as the sum of a Levi-Civita connection and terms depending on a
vector field. However, while in case i) this vector field is related to the
symmetric part of the connection, in ii) it comes from the torsion part and,
therefore, it vanishes once torsion is completely removed. Moreover, the
vanishing of this torsion-related vector field immediately implies the
vanishing of the antisymmetric part of the Ricci tensor, which therefore plays
no role in the dynamics. Related to this, we find that the Levi-Civita part of
the connection is due to the existence of an invariant volume associated to an
auxiliary metric $h_{\mu\nu}$, which is algebraically related with the physical
metric $g_{\mu\nu}$.


title: Quasi-representations of surface groups

abstract:
  By a quasi-representation of a group $G$ we mean an approximately
multiplicative map of $G$ to the unitary group of a unital $C^*$-algebra. A
quasi-representation induces a partially defined map at the level $K$-theory.
  In the early 90s Exel and Loring associated two invariants to
almost-commuting pairs of unitary matrices $u$ and $v$: one a $K$-theoretic
invariant, which may be regarded as the image of the Bott element in
$K_0(C(\mathbb{T}^2))$ under a map induced by quasi-representation of
$\mathbb{Z}^2$ in U(n); the other is the winding number in $\mathbb{C}\setminus
\{0\}$ of the closed path $t\mapsto \det(tvu + (1-t)uv)$. The so-called
Exel-Loring formula states that these two invariants coincide if $\|uv - vu\|$
is sufficiently small.
  A generalization of the Exel-Loring formula for quasi-representations of a
surface group taking values in U(n) was given by the second-named author. Here
we further extend this formula for quasi-representations of a surface group
taking values in the unitary group of a tracial unital $C^*$-algebra.


title:
Optimized structure and vibrational properties by error affected
  potential energy surfaces

abstract:
  The precise theoretical determination of the geometrical parameters of
molecules at the minima of their potential energy surface and of the
corresponding vibrational properties are of fundamental importance for the
interpretation of vibrational spectroscopy experiments. Quantum Monte Carlo
techniques are correlated electronic structure methods promising for large
molecules, which are intrinsically affected by stochastic errors on both energy
and force calculations, making the mentioned calculations more challenging with
respect to other more traditional quantum chemistry tools. To circumvent this
drawback in the present work we formulate the general problem of evaluating the
molecular equilibrium structures, the harmonic frequencies and the anharmonic
coefficients of an error affected potential energy surface. The proposed
approach, based on a multidimensional fitting procedure, is illustrated
together with a critical evaluation of systematic and statistical errors. We
observe that the use of forces instead of energies in the fitting procedure
reduces the the statistical uncertainty of the vibrational parameters by one
order of magnitude. Preliminary results based on Variational Monte Carlo
calculations on the water molecule demonstrate the possibility to evaluate
geometrical parameters, harmonic and anharmonic coefficients at this level of
theory with an affordable computational cost and a small stochastic uncertainty
(<0.07% for geometries and <0.7% for vibrational properties).

categories: cond-mat.str-el physics.chem-ph physics.comp-ph quant-ph


title: On the magnetic monopole mass

abstract:
  Magnetic monopoles have been a subject of interest since Dirac established
the relation between the existence of a monopole and charge quantization. 't
Hooft and Polyakov proved that they can arise from gauge theories as the result
of a non trivial topology. In their scheme the mass of the monopole turns out
to be large proportional to the vector meson mass arising from the spontaneous
breaking of the symmetry at unification scales. To reduce from the GUT scale to
the Standard Model scale we modify the potential in line with Coleman-Weinberg
schemes and generate a second deeper minimum turning the original vacuum
quantum mechanically unstable. This mechanism leads to radiating monopoles of
lower mass which could be detected at LHC.


title:
Modification in structural, dielectric and magnetic properties of La and
  Nd co-substituted epitaxial BiFeO3 thin films

abstract:
  The influence of La and Nd co-substitution on the structural and magnetic
properties of BiFeO3 (BFO) thin films was examined. Epitaxial thin films of
pure and, La and Nd co-doped BFO on the SrRuO3 buffered single crystal SrTiO3
(001) substrate were deposited using pulsed laser deposition. The structural
change in co doped La and Nd BFO thin films which was caused by the changes of
force constant in the crystal lattice induced by ionic radii mismatch was
investigated. Raman spectroscopy studies manifest the structural change in
doped BFO films from rhombohedral to monoclinic distorted phase which is
induced by the co substitution of La and Nd. Room temperature magnetic
hysteresis curves indicated that saturation magnetization is enhanced in the
doped film with saturation magnetization of ~20 emu/cm3. The dielectric and
magnetic properties are effectively improved in BLNFO films compared to pure
BFO thin films.


title:
Superbosonisation, Riesz superdistributions, and highest weight modules
  (extended version)

abstract:
  This is the extended version of a survey prepared for publication in the
Springer INdAM series.
  Superbosonisation, introduced by Littelmann-Sommers-Zirnbauer, is a
generalisation of bosonisation, with applications in Random Matrix Theory and
Condensed Matter Physics. We link the superbosonisation identity to
Representation Theory and Harmonic Analysis and explain two new proofs, one via
the Laplace transform and one based on a multiplicity freeness statement.


title: Spectrum of a magnetized strong-leg quantum spin ladder

abstract:
  Inelastic neutron scattering is used to measure the spin excitation spectrum
of the Heisenberg $S=1/2$ ladder material (C$_7$H$_10$N)$_2$CuBr$_4$ in its
entirety, both in the gapped spin-liquid and the magnetic field induced
Tomonaga-Luttinger spin liquid regimes. A fundamental change of the spin
dynamics is observed between these two regimes. DMRG calculations
quantitatively reproduce and help understand the observed commensurate and
incommensurate excitations. The results validate long-standing quantum field
theoretical predictions, but also test the limits of that approach.


title:
Elastic scattering of protons from sqrt{s}=23.5 GeV to 7 TeV from a
  generalized Bialas-Bzdak model

abstract:
  The Bialas-Bzdak model of elastic proton-proton scattering is generalized to
the case when the real part of the parton-parton level forward scattering
amplitude is non-vanishing. Such a generalization enables the model to describe
well the dip region of the differential cross-section of elastic scattering at
the ISR energies, and improves significantly the ability of the model to
describe also the recent TOTEM data at sqrt{s} = 7 TeV LHC energy. Within this
framework, both the increase of the total cross-section, as well as the
decrease of the location of the dip with increasing colliding energies, is
related to the increase of the quark-diquark distance and to the increase of
the "fragility" of the protons with increasing energies. In addition, we
present and test the validity of two new phenomenological relations: one of
them relates the total p+p cross-section to an effective, model-independent
proton radius, while the other relates the position of the dip in the
differential elastic cross-section to the measured value of the total
cross-section.


title: A Mass-Conserving 4D XCAT Phantom for Dose Calculation and Accumulation

abstract:
  The XCAT phantom is a realistic 4D digital torso phantom that is widely used
in imaging and therapy research. However, lung mass is not conserved between
respiratory phases of the phantom, making detailed dosimetric simulations and
dose accumulation unphysical. A framework is developed to correct this issue by
enforcing local mass conservation in the XCAT lung. Dose calculations are
performed to assess the implications of neglecting mass conservation, and to
demonstrate an application of the phantom to calculate the accumulated
delivered dose in an irregularly breathing patient. Monte Carlo methods are
used to simulate conventional and SBRT treatment delivery. The spatial
distribution of the lung dose was qualitatively changed by the use of mass
conservation; however the corresponding DVH did not change significantly.
Comparison of the delivered dose with 4DCT-based predictions shows similar lung
metric results, however dose differences of 10% can be seen in some spatial
regions. Using this tool to simulate patient treatments reveals differences
between the planned dose and the calculated delivered dose for the full
treatment. The software is freely available from the authors.


title: Inspection and crime prevention: an evolutionary perspective

abstract:
  In this paper, we analyse inspection games with an evolutionary perspective.
In our evolutionary inspection game with a large population, each individual is
not a rational payoff maximiser, but periodically updates his strategy if he
perceives that other individuals' strategies are more successful than his own,
namely strategies are subject to the evolutionary pressure. We develop this
game into a few directions. Firstly, social norms are incorporated into the
game and we analyse how social norms may influence individuals' propensity to
engage in criminal behaviour. Secondly, a forward-looking inspector is
considered, namely, the inspector chooses the level of law enforcement whilst
taking into account the effect that this choice will have on future crime
rates. Finally, the game is extended to the one with continuous strategy
spaces.


title: Partial Decoherence and Thermalization through Time-Domain Ergodicity

abstract:
  An approach, differing from two commonly used methods (the stochastic \SE \
and the master equation \cite {Schlosshauer,BieleA}) but entrenched in the
traditional density matrix formalism, is developed in a semi-classical setting,
so as to go from the solutions of the time dependent \SE to decohering and
thermalized states. This is achieved by utilizing the time-ergodicity, rather
than the sampling- (or ensemble-) ergodicity, of physical systems.
  We introduce the formalism through a study of the Rabi model (a two level
system coupled to an oscillator) and show that our semi-classical version
exhibits, both qualitatively and quantitatively, many features of state
truncation and equilibration \cite {AllahverdyanBN}. We then study the time
evolution of two qubits in interaction with a bosonic environment, such that
the energy scale of one qubit is much larger, and that of the other much
smaller than the environment's energy scale. The small energy qubit decoheres
to a mixture, while the high energy qubit is protected through the adiabatic
theorem. However, an inter-qubit coupling generates an overall decoherence and
leads for some values of the coupling to long term revivals in the state
occupations.


title:
The optimal hyperball packings related to the smallest compact
  arithmetic 5-orbifolds

abstract:
  The smallest three hyperbolic compact arithmetic 5-orbifolds can be derived
from two compact Coxeter polytops which are combinatorially simplicial prisms
(or complete orthoschemes of degree $d=1$) in the five dimensional hyperbolic
space $\mathbf{H}^5$ (see \cite{BE} and \cite{EK}). The corresponding
hyperbolic tilings are generated by reflections through their delimiting
hyperplanes those involve the study of the relating densest hyperball
(hypersphere) packings with congruent hyperballs.
  The analogous problem was discussed in \cite{Sz06-1} and \cite{Sz06-2} in the
hyperbolic spaces $\mathbf{H}^n$ $(n=3,4)$. In this paper we extend this
procedure to determine the optimal hyperball packings to the above
5-dimensional prism tilings. We compute their metric data and the densities of
their optimal hyperball packings, moreover, we formulate a conjecture for the
candidate of the densest hyperball packings in the 5-dimensional hyperbolic
space $\mathbf{H}^5$.


title:
Of Substitution and Doping: Spatial and Electronic Structure in Fe
  Pnictides

abstract:
  A highly intriguing aspect in iron-pnictide superconductors is the
composition-dependent electronic structure, in particular the question if and
how charge carriers are introduced to the system upon substitution of Ba by
alkali metals or of Fe by other transition metals, TM. We report on a
systematic study of spatial structure and electronic states by x-ray
diffraction and x-ray absorption on a large number of compositions in the
(Ba,K)(Fe,TM)2As2 family. The coherent combination of detailed structural
information with an in-depth analysis of the electronic structure allows us to
sensitively disentangle (charge-carrier) "doping" effects from "substitutional"
effects. Results include a doping character that is site-decoupled, as well as
TM 3d energy-level schemes that exhibit non-standard level sequences and even
t2-e level crossings. Our study indicates that doping per se seems to play a
lesser role than expected for pnictide superconductivity and magnetism.


title:
Growth in the number of references in engineering journal papers during
  the 1972-2013 period

abstract:
  The number of references per paper, perhaps the best single index of a
journal's scholarliness, has been studied in different disciplines and periods.
In this paper we present a four decade study of eight engineering journals. A
data set of over 70000 references was generated after automatic data gathering
and manual inspection for errors. Results show a significant increase in the
number of references per paper, the average rises from 8 in 1972 to 25 in 2013.
This growth presents an acceleration around the year 2000, consistent with a
much easier access to search engines and documents produced by the
generalization of the Internet.


title: Chemical abundances in LMC stellar populations. II. The bar sample

abstract:
  This paper compares the chemical evolution of the Large Magellanic Cloud
(LMC) to that of the Milky Way (MW) and investigates the relation between the
bar and the inner disc of the LMC in the context of the formation of the bar.
We obtained high-resolution and mid signal-to-noise ratio spectra with
FLAMES/GIRAFFE at ESO/VLT and performed a detailed chemical analysis of 106 and
58 LMC field red giant stars (mostly older than 1 Gyr), located in the bar and
the disc of the LMC respectively. We measured elemental abundances for O, Mg,
Si, Ca, Ti, Na, Sc, V, Cr, Co, Ni, Cu, Y, Zr, Ba, La and Eu. We find that the
{\alpha}-element ratios [Mg/Fe] and [O/Fe] are lower in the LMC than in the MW
while the LMC has similar [Si/Fe], [Ca/Fe], and [Ti/Fe] to the MW. As for the
heavy elements, [Ba,La/Eu] exhibit a strong increase with increasing
metallicity starting from [Fe/H]=-0.8 dex, and the LMC has lower [Y+Zr/Ba+La]
ratios than the MW. Cu is almost constant over all metallicities and about 0.5
dex lower in the LMC than in the MW. The LMC bar and inner disc exhibit
differences in their [{\alpha}/Fe] (slightly larger scatter for the bar in the
metallicity range [-1,-0.5]), their Eu (the bar trend is above the disc trend
for [Fe/H] > -0.5 dex), their Y and Zr, their Na and their V (offset between
bar and disc distributions). Our results show that the chemical history of the
LMC experienced a strong contribution from type Ia supernovae as well as a
strong s-process enrichment from metal-poor AGB winds. Massive stars made a
smaller contribution to the chemical enrichment compared to the MW. The
observed differences between the bar and the disc speak in favour of an episode
of enhanced star formation a few Gyr ago, occurring in the central parts of the
LMC and leading to the formation of the bar. This is in agreement with recently
derived star formation histories.


title:
Note on Malmst\`en's paper De Integralibus quibusdam definitis
  seriebusque infinitis

abstract:
  We present a proof of the functional equation of the Riemann zeta-function or
more precisely the Dirichlet eta-function, which proof seems to be new but
follows almost immediately from Malmst\`en's paper ``De integralibus quibusdam
definitis seriebusque infinitis``


title: Optical stabilization of voltage fluctuations in half-Josephson lasers

abstract:
  A recently proposed device, dubbed half-Josephson laser, provides a
phase-lock between the optical phase and the superconducting phase difference
between the leads of the device. In this paper we propose to utilize this
phase-lock for stabilization of voltage fluctuations, by two optical feedback
schemes. The first scheme involves a single half-Josephson laser and allows to
significantly decrease the diffusion coefficient of the superconducting phase
difference. The second scheme involves a stable optical source and a
fluctuating half-Josephson laser and permits quenching of the diffusion of the
relative phase of the lasers. This opens up perspectives of the optical control
of the superconducting phase and voltage fluctuations.


title: Super-Whittaker vector at c=3/2

abstract:
  The degenerate Whittaker vector of the superconformal algebra can be
represented in terms of Jack superpolynomials. However, in this representation
the norm of the Whittaker vector involves a scalar product with respect to
which the Jack superpolynomials are not orthogonal. In this note, we point out
that this defect can be cured at c=3/2 by means of a trick specific to the
supersymmetric case. At c=3/2, we thus end up with a closed-form expression for
the norm of the degenerate super-Whittaker vector. Granting the super-version
of the AGT conjecture, this closed-form expression should be equal to the
Z_2-symmetric SU(2) pure-gauge instanton partition function -- the
corresponding equality taking the form of a rather nontrivial combinatorial
identity.


title: On Nelson Goodman's final formulae for Primary Complexity

abstract:
  In the Structure of Appearance and in Problems and Projects, Nelson Goodman
has constructed a theory of complexity whose elements are the predicates of a
system. One of his main results is a closed formula to evaluate v[n-pl], the
maximum complexity value of an n-place predicate. Up to this day no procedure
has been found to reduce v[n-pl], i.e., to write it in terms of (n-1)-place
predicates. In this article we propose elementary combinatorial algorithms to
carry out such a reduction.


title:
Cryogenic on-chip multiplexer for the study of quantum transport in 256
  split-gate devices

abstract:
  We present a multiplexing scheme for the measurement of large numbers of
mesoscopic devices in cryogenic systems. The multiplexer is used to contact an
array of 256 split gates on a GaAs/AlGaAs heterostructure, in which each split
gate can be measured individually. The low-temperature conductance of
split-gate devices is governed by quantum mechanics, leading to the appearance
of conductance plateaux at intervals of 2e^2/h. A fabrication-limited yield of
94% is achieved for the array, and a "quantum yield" is also defined, to
account for disorder affecting the quantum behaviour of the devices. The
quantum yield rose from 55% to 86% after illuminating the sample, explained by
the corresponding increase in carrier density and mobility of the
two-dimensional electron gas. The multiplexer is a scalable architecture, and
can be extended to other forms of mesoscopic devices. It overcomes previous
limits on the number of devices that can be fabricated on a single chip due to
the number of electrical contacts available, without the need to alter existing
experimental set ups.


title: On the Broadcast Latency in Finite Cooperative Wireless Networks

abstract:
  The aim of this paper is to study the effect of cooperation on system delay,
quantified as the number of retransmissions required to deliver a broadcast
message to all intended receivers. Unlike existing works on broadcast
scenarios, where distance between nodes is not explicitly considered, we
examine the joint effect of small scale fading and propagation path loss. Also,
we study cooperation in application to finite networks, i.e. when the number of
cooperating nodes is small. Stochastic geometry and order statistics are used
to develop analytical models that tightly match the simulation results for
non-cooperative scenario and provide a lower bound for delay in a cooperative
setting. We demonstrate that even for a simple flooding scenario, cooperative
broadcast achieves significantly lower system delay.