title: Contributions to the theory of de Bruijn cycles

abstract:
  A de Bruijn cycle is a cyclic listing of length A, of a collection of A
combinatorial objects, so that each object appears exactly once as a set of
consecutive elements in the cycle. In this paper, we show the power of de
Bruijn's original theorem, namely that the cycles bearing his name exist for
n-letter words on a k-letter alphabet for all values of k,n, to prove that we
can create de Bruijn cycles for the assignment of elements of [n]={1,2,....,n}
to the sets in any labeled subposet of the Boolean lattice; de Bruijn's theorem
corresponds to the case when the subposet in question consists of a single
ground element. The landmark work of Chung, Diaconis, and Graham extended the
agenda of finding de Bruijn cycles to possibly the next most natural set of
combinatorial objects, namely k-subsets of [n]. In this area, important
contributions have been those of Hurlbert and Rudoy. Here we follow the
direction of Blanca and Godbole, who proved that, in a suitable encoding, de
Bruijn cycles can be created for the subsets of [n$ of size in the interval
[s,t]; 0<=s<t<=n$. In this paper we generalize this result to exhibit existence
of de Bruijn cycles for words with weight between s and t, where these
parameters are suitably restricted.


title: How stable is the photon?

abstract:
  Yes, the photon. While a nonzero photon mass has been under experimental and
theoretical study for years, the possible implication of a finite photon
lifetime lacks discussion. The tight experimental upper bound of the photon
mass restricts the kinematically allowed final states of photon decay to the
lightest neutrino and/or particles beyond the Standard Model. We discuss the
modifications of the well-measured cosmic microwave background spectrum of free
streaming photons due to photon mass and lifetime and obtain model-independent
constraints on both parameters---most importantly a lower direct bound of 3 yr
on the photon lifetime, should the photon mass be at its conservative upper
limit. In that case, the lifetime of microwave photons will be time-dilated by
a factor order 10^(15).


title: Longitudinal Single Bunch Instability Study on BEPCII

abstract:
  In order to study the single bunch longitudinal instability in BEPCII,
experiments on the positron ring (BPR) for the bunch lengthening phenomenon
were made. By analyzing the experimental data based on Gao's theory, the
longitudinal loss factor for the bunch are obtained. Also, the total wake
potential and the beam current threshold are estimated.


title: The Maintenance of Sex: Ronald Fisher meets the Red Queen

abstract:
  Sex in higher diploids carries a two-fold cost of males that should reduce
its fitness relative to cloning and result in its extinction. Instead, sex is
widespread and it is clonal species that face early obsolescence. One possible
reason is that sex is an adaptation to resist ubiquitous parasites, which
evolve rapidly and potentially antagonistically. We use a heuristic approach to
model mutation-selection in finite populations where a parasitic haploid mounts
a negative frequency-dependent attack on a diploid host. The host evolves
reflexively to reduce parasitic load. Both host and parasite populations
generate novel alleles by mutation and have access to large allele spaces. Sex
outcompetes cloning by two overlapping mechanisms. First, sexual diploids adopt
advantageous homozygous mutations more rapidly than clonal diploids under
conditions of lag load. This rate advantage can offset the lesser fecundity of
sex. Second, a relative advantage to sex emerges under host mutation rates that
are fast enough to retain fitness in a rapidly mutating parasite environment
and increase host polymorphism. Clonal polymorphic populations
disproportionately experience interference with selection at high mutation
rates, both between and within loci. This slows clonal population adaptation to
a changing parasite environment and reduces clonal population fitness relative
to sex. The interference increases markedly with the number of loci under
independent selection. Rates of parasite mutation exist that not only allow sex
to survive despite the two-fold cost of males but which enable sexual and
clonal populations to have equal fitness and co-exist. Since all higher
organisms carry parasitic loads, the model is of general applicability.


title:
Newtonian polytropes for anisotropic matter: General framework and
  applications

abstract:
  We set up the general formalism to model polytropic Newtonian stars with
anisotropic pressure. We obtain the corresponding Lane-Emden equation. A
heuristic model based on an ansatz to obtain anisotropic matter solutions from
known solutions for isotropic matter is adopted to illustrate the effects of
the pressure anisotropy on the structure of the star. In particular, we
calculate the Chandrasekhar mass for a white dwarf. It is clearly displayed how
the Chandrasekhar mass limit changes depending on the anisotropy. Prospective
astrophysical applications of the proposed approach are discussed.


title:
Physics performances for Scalar Electron, Scalar Muon and Scalar
  Neutrino searches at 3 TeV and 1.4 TeV at CLIC

abstract:
  The determination of scalar lepton and gaugino masses is an important part of
the programme of spectroscopic studies of Supersymmetry at a high energy e+e-
linear collider. In this article we present results of a study of the
processes: e+e- -> eR eR -> e+e- chi0 chi, e+e- -> muR muR -> mu mu- chi0 chi0,
e+e- -> eL eL -> e e chi0 chi0 and e+e- -> snu_e snu_e -> e e chi+ chi-in two
Supersymmetric benchmark scenarios at 3 TeV and 1.4 TeV at CLIC. We
characterize the detector performance, lepton energy resolution and boson mass
resolution. We report the accuracy of the production cross section measurements
and the eR muR, snu_e, chi+ and chi0 mass determination, estimate the
systematic errors affecting the mass measurement and discuss the requirements
on the detector time stamping capability and beam polarization. The analysis
accounts for the CLIC beam energy spectrum and the dominant beam-induced
background. The detector performances are incorporated by full simulation and
reconstruction of the events within the framework of the CLIC_ILD_CDR detector
concept.


title:
Magnetization and spin dynamics of the spin S=1/2 hourglass nanomagnet
  Cu5(OH)2(NIPA)4*10H2O

abstract:
  We report a combined experimental and theoretical study of the spin S=1/2
nanomagnet Cu5(OH)2(NIPA)4*10H2O (Cu5-NIPA). Using thermodynamic, electron spin
resonance and 1H nuclear magnetic resonance measurements on one hand, and ab
initio density-functional band-structure calculations, exact diagonalizations
and a strong coupling theory on the other, we derive a microscopic magnetic
model of Cu5-NIPA and characterize the spin dynamics of this system. The
elementary five-fold Cu2+ unit features an hourglass structure of two
corner-sharing scalene triangles related by inversion symmetry. Our microscopic
Heisenberg model comprises one ferromagnetic and two antiferromagnetic exchange
couplings in each triangle, stabilizing a single spin S=1/2 doublet ground
state (GS), with an exactly vanishing zero-field splitting (by Kramer's
theorem), and a very large excitation gap of \Delta~68 K. Thus, Cu5-NIPA is a
good candidate for achieving long electronic spin relaxation (T1) and coherence
(T2) times at low temperatures, in analogy to other nanomagnets with low-spin
GS's. Of particular interest is the strongly inhomogeneous distribution of the
GS magnetic moment over the five Cu2+ spins. This is a purely
quantum-mechanical effect since, despite the non-frustrated nature of the
magnetic couplings, the GS is far from the classical collinear ferrimagnetic
configuration. Finally, Cu5-NIPA is a rare example of a S=1/2 nanomagnet
showing an enhancement in the nuclear spin-lattice relaxation rate 1/T1 at
intermediate temperatures.


title:
Holomorphic curves into infinite dimensional almost K\"ahler manifolds
  and Hamiltonian dynamics

abstract:
  We study analysis over infinite dimensional manifolds consisted by sequences
of almost K\"ahler manifolds. In particular we develop moduli theory of pseudo
holomorphic curves into the spaces with high symmetry.
  As applications, we study Hamiltonian dynamics over the infinite dimensional
manifolds, and induce some dynamical properties of Hamiltonian diffeomorphisms
on such spaces.


title: Cross-Validation for Nonlinear Mixed Effects Models

abstract:
  Cross-validation is frequently used for model selection in a variety of
applications. However, it is difficult to apply cross-validation to mixed
effects models (including nonlinear mixed effects models or NLME models) due to
the fact that cross-validation requires "out-of-sample" predictions of the
outcome variable, which cannot be easily calculated when random effects are
present. We describe two novel variants of cross-validation that can be applied
to nonlinear mixed effects models. One variant, where out-of-sample predictions
are based on post hoc estimates of the random effects, can be used to select
the overall structural model. Another variant, where cross-validation seeks to
minimize the estimated random effects rather than the estimated residuals, can
be used to select covariates to include in the model. We show that these
methods produce accurate results in a variety of simulated data sets and apply
them to two publicly available population pharmacokinetic data sets.


title: Duality constrained meta atoms for transformation optics

abstract:
  Maxwell's equations in curved space-time are invariant under electromagnetic
duality transformations. We exploit this property to constraint the design
parameters of metamaterials used for transformations optics. We show that a
general transformation must be implemented using a dual-symmetric metamaterial.
This can be accomplished constraining the polarisability tensors of their
individual constituents, i.e. the meta atoms. We obtain explicit expressions
for these constraints. We also show that the spatial part of the coordinate
transformation depends only on the electric-electric tensorial coupling of the
polarisability tensor, while the spatio-temporal part depends only on the
electric-magnetic tensorial coupling. In our derivations, we find that two
dipoles located at the same point, one electric (p) and one magnetic (m), are
needed to produce a total field with well defined helicity equal to +1 or -1,
and that they must be related as p=im/c or p=-im/c, respectively.


title: Counting Free Abelian Actions

abstract:
  We consider the problem of counting commuting r-tuples of elements of the
symmetric group S_n, i.e. computing |Hom(Z^r,S_n)|. The cases r=1,2 are
well-known; a product formula for the case r=3 was conjectured by Adams-Watters
and later proved by Britnell. In this note we solve the problem for arbitrary
r.


title:
The Ultraviolet/optical variability of steep-spectrum radio quasars: the
  change in accretion rate ?

abstract:
  Context. The steep-spectrum radio quasars (SSRQs) are powerful radio sources,
with thermal emission from accretion disk and jet nonthermal emission likely
both contributing in the Ultraviolet (UV)/optical luminosity, however the
former may play a dominant role. While the UV/optical variability of SSRQs has
been poorly studied, little is known on the mechanism of their variability.
Aims. We investigate the mechanism of the UV/optical variability of SSRQs.
Methods. A sample of eighteen SSRQs has been established in SDSS Stripe 82
region in our previous works, in which the flux and spectral variability have
been studied. In this work, we construct the flux-flux diagram using SDSS u and
i multi-epoch data for these eighteen SSRQs. The standard accretion disk model
is used to fit the flux-flux variations, in order to explore the variability
mechanism. Results. The model fit to flux-flux diagram are tuned with fixed
black hole mass and varying accretion rate. We found that the flux-flux diagram
of all our SSRQs can be qualitatively described by the standard accretion disk
model with change of the accretion rate. Although non-thermal jet power-law
emission can also qualitatively reproduce the variability, the reasonable
accretion rates and black hole masses required to fit the flux-flux variations
suggest that a disk emission with variable accretion rate is a plausible
description of the data.


title:
More On Superstring Perturbation Theory: An Overview Of Superstring
  Perturbation Theory Via Super Riemann Surfaces

abstract:
  This article is devoted to an overview of superstring perturbation theory
from the point of view of super Riemann surfaces. We aim to elucidate some of
the subtleties of superstring perturbation that caused difficulty in the early
literature, focusing on a concrete example -- the $SO(32)$ heterotic string
compactified on a Calabi-Yau manifold, with the spin connection embedded in the
gauge group. This model is known to be a significant test case for superstring
perturbation theory. Supersymmetry is spontaneously broken at 1-loop order, and
to treat correctly the supersymmetry-breaking effects that arise at 1- and
2-loop order requires a precise formulation of the procedure for integration
over supermoduli space. In this paper, we aim as much as possible for an
informal explanation, though at some points we provide more detailed
explanations that can be omitted on first reading.


title: Rindler Space and Unruh Effect

abstract:
  We review the geometry of the Rindler space induced by hyperbolic motion in
special relativity, and its applications to the calculation of the Unruh effect
in flat spacetime, and to the Hawking temperature of the Schwarzschild black
hole.


title: The McMullen Map in Positive Characteristic

abstract:
  McMullen proved the moduli space of complex rational maps can be parametrized
by the spectrum of all periodic-point multipliers up to a finite amount of
data, with the well-understood exception of Latt\`{e}s maps. We generalize his
method to large positive characteristic. McMullen's method is analytic; a
modified version of the method using rigid analysis works over a function field
over a finite field of characteristic larger than the degree of the map. Over a
finite field with such characteristic it implies that, generically, rational
maps can indeed be parametrized by their multiplier spectra up to a
finite-to-one map. Moreover, the set of exceptions, that is positive-dimension
varieties in moduli space with identical multipliers, maps to just a finite set
of multiplier spectra. We also prove an application, generalizing a result of
McMullen over the complex numbers: there is no generally convergent purely
iterative root-finding algorithm over a non-archimedean field whose residue
characteristic is larger than either the degree of the algorithm or the degree
of the polynomial whose roots the algorithm finds.


title: The spectral variability in radio-loud quasars

abstract:
  The spectral variability of a sample of 44 flat-spectrum radio quasars
(FSRQs) and 18 steep-spectrum radio quasars (SSRQs) in the SDSS stripe 82
region is investigated. Twenty-five of 44 FSRQs show a bluer-when-brighter
trend (BWB), while only one FSRQ shows a redder-when-brighter trend, which is
in contrast to our previous results. Eight of 18 SSRQs display a BWB. We found
an anti-correlation between the Eddington ratio and the variability amplitude
in r band for SSRQs, which is similar to that in radio-quiet AGNs. This implies
that the thermal emission from the accretion disk may be responsible for the
variability in SSRQs. The spectral variability from the SDSS multi-epoch
spectroscopy also shows BWB for several SSRQs, consistent with that from
photometry.


title:
Numerical simulations of single and binary black holes in scalar-tensor
  theories: circumventing the no-hair theorem

abstract:
  Scalar-tensor theories are a compelling alternative to general relativity and
one of the most accepted extensions of Einstein's theory. Black holes in these
theories have no hair, but could grow "wigs" supported by time-dependent
boundary conditions or spatial gradients. Time-dependent or spatially varying
fields lead in general to nontrivial black hole dynamics, with potentially
interesting experimental consequences. We carry out a numerical investigation
of the dynamics of single and binary black holes in the presence of scalar
fields. In particular we study gravitational and scalar radiation from
black-hole binaries in a constant scalar-field gradient, and we compare our
numerical findings to analytical models. In the single black hole case we find
that, after a short transient, the scalar field relaxes to static
configurations, in agreement with perturbative calculations. Furthermore we
predict analytically (and verify numerically) that accelerated black holes in a
scalar-field gradient emit scalar radiation. For a quasicircular black-hole
binary, our analytical and numerical calculations show that the dominant
component of the scalar radiation is emitted at twice the binary's orbital
frequency.


title: Approximating random quantum optimization problems

abstract:
  We report a cluster of results regarding the difficulty of finding
approximate ground states to typical instances of the quantum satisfiability
problem $k$-QSAT on large random graphs. As an approximation strategy, we
optimize the solution space over `classical' product states, which in turn
introduces a novel autonomous classical optimization problem, PSAT, over a
space of continuous degrees of freedom rather than discrete bits. Our central
results are: (i) The derivation of a set of bounds and approximations in
various limits of the problem, several of which we believe may be amenable to a
rigorous treatment. (ii) A demonstration that an approximation based on a
greedy algorithm borrowed from the study of frustrated magnetism performs well
over a wide range in parameter space, and its performance reflects structure of
the solution space of random $k$-QSAT. Simulated annealing exhibits
metastability in similar `hard' regions of parameter space. (iii) A
generalization of belief propagation algorithms introduced for classical
problems to the case of continuous spins. This yields both approximate
solutions, as well as insights into the free energy `landscape' of the
approximation problem, including a so-called dynamical transition near the
satisfiability threshold. Taken together, these results allow us to elucidate
the phase diagram of random $k$-QSAT in a two-dimensional
energy-density--clause-density space.


title: EIT-like phenomenon with two atomic ensembles in a cavity

abstract:
  We study the spectra of collective low excitations of two atomic ensembles
coupled indirectly through a single-mode cavity field. When the left ensemble
is driven with an external optical field, its corresponding response spectrum
to the incident optical light shows an electromagnetically induced
transparency- (EIT-) like phenomenon when the layers are arranged in the
sequence of node-antinode but not in the sequence of antinode-node. In the case
of antinode-antinode sequence, the response spectrum shows an EIT-like
phenomenon with two transparent windows. We also investigate the fluctuation
spectra of the atomic collective excitation modes, which show similar EIT-like
phenomena.


title:
Amenability and Unique Ergodicity of Automorphism Groups of Fra\"iss\'e
  Structures

abstract:
  In this paper we provide a necessary and sufficient condition for the
amenability of the automorphism group of Fra\"iss\'e structures and apply it to
prove the non-amenability of the automorphism groups of the directed graph
$\mathbf{S}(3)$ and the Boron tree structure $\mathbf{T}$. Also, we provide a
negative answer to the Unique Ergodicity-Generic Point problem of
Angel-Kechris-Lyons [AKL]. By considering $\mathrm{GL}(\mathbf{V}_\infty)$,
where $\mathbf{V}_\infty$ is the countably infinite dimensional vector space
over a finite field $F_q$, we show that the unique invariant measure on the
universal minimal flow of $\mathrm{GL}(\mathbf{V}_\infty)$ is not supported on
the generic orbit.


title:
Cross-layer Application-aware Power/Energy Management for Extreme Scale
  Science

abstract:
  High Performance Computing (HPC) has evolved over the past decades into
increasingly complex and powerful systems. Current HPC systems consume several
MWs of power, enough to power small towns, and are in fact soon approaching the
limits of the power available to them. Estimates are with the given current
technology, achieving exascale will require hundreds of MW, which is not
feasible from multiple perspectives. Architecture and technology researchers
are aggressively addressing this; however as past history is shown, innovation
at these levels are not sufficient and have to be accompanied with innovations
at higher levels (algorithms, programming, runtime, OS) to achieve the multiple
orders of magnitude reduction - i.e., a comprehensive cross-layer and
application-aware strategy is required. Furthermore, energy/power-efficiency
has to be addressed in combination with quality of solutions, performance and
reliability and other objectives and appropriate tradeoffs are required.


title:
Dijet asymmetry in Pb+Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 2.76 TeV
  within a multiphase transport model

abstract:
  Within a multi-phase transport (AMPT) model, dijet asymmetry is studied in
Pb+Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 2.76 TeV. It is found that a large
dijet asymmetry ($A_{J}$) is produced by strong interactions between jets and
partonic matter. It is demonstrated that hadronization and final-state hadronic
rescatterings have little effects on $A_{J}$. The final $A_{J}$ is found to be
driven by both initial $A_{J}$ and partonic jet energy loss, which is
consistent with an increasing jet energy loss in a hot and strongly interacting
partonic medium in more central Pb+Pb collisions.


title:
Anomalous Diffuse Interstellar Bands in the Spectrum of Herschel 36. II.
  Analysis of Radiatively Excited CH+, CH, and DIBs

abstract:
  Absorption spectra toward Herschel 36 for the A^1Pi <-- X^1Sigma transitions
of CH+ in the J=1 excited rotational level and the A^2Delta <-- X^2Pi
transition of CH in the J=3/2 excited fine structure level have been analyzed.
These excited levels are above their ground levels by 40.1 K and ~25.7 K and
indicate high radiative temperatures of the environment, 14.6 K and 6.7 K,
respectively. The effect of the high radiative temperature is more spectacular
in some diffuse interstellar bands (DIBs) observed toward Her 36; remarkable
extended tails toward red (ETR) were observed. We interpret these ETRs as due
to a small decrease of rotational constants upon excitation of excited
electronic states. Along with radiative pumping of a great many high-J
rotational levels, this causes the ETRs. In order to study this effect
quantitatively, we have developed a model calculation in which the effects of
collision and radiation are treated simultaneously. The simplest case of linear
molecules is considered. It has been found that the ETR is reproduced if the
fraction of the variation of the rotational constant, beta = (B'-B)/B, is
sufficiently high (3-5%) and the radiative temperature is high (T_r > 50 K).
Although modeling for general molecules is beyond the scope of this paper, the
results indicate that the prototypical DIBs at 5780.5, 5797.1, and 6613.6 A
which show the pronounced ETRs are due to polar molecules sensitive to the
radiative excitation. The requirement of high beta favors relatively small
molecules with 3-6 heavy atoms. DIBs at 5849.8, 6196.0, and 6379.3 A which do
not show the pronounced ETRs are likely due to non-polar molecules or large
polar molecules with small beta.


title: On the automorphism groups of models in $\mathbb C^2$

abstract:
  In this note, we consider models in $\mathbb C^2$. The purpose of this note
is twofold. We first show a characterization of models in $\mathbb C^2$ by
their noncompact automorphism groups. Then we give an explicit description for
automorphism groups of models in $\mathbb C^2$.


title: Pinning in a Porous Bi2223

abstract:
  The current-voltage characteristics of a porous superconductor Bi2Sr2Ca2Cu3Ox
(Bi2223) have been measured at temperature range from 10 to 90 K. The
experimental dependences have been analyzed within the model allowing for
pinning by clusters of a normal phase with fractal boundaries, as well as the
model taking into account phase transformations of vortex matter. It has been
found that the electrical resistance of the superconductor material
significantly increases at temperatures of 60-70 K over the entire range of
magnetic fields under consideration without changing in the sign of the
curvature of the R(I) dependence. The melting of the vortex structure occurs at
these temperatures. It has been assumed that this behavior is associated with
the specific feature of the pinning in a highly porous high-temperature
superconductor, which lies in the fractal distribution of pinning centers in a
wide range of self-similarity scales.


title:
Subthreshold behavior and avalanches in an exactly solvable Charge
  Density Wave system

abstract:
  We present a toy charge density wave (CDW) model in 1d exhibiting a depinning
transition with threshold force and configurations that are explicit. Due to
the periodic boundary conditions imposed, the threshold configuration has a set
of topological defects whose location and number depend on the realization of
the random phases. Approaching threshold, these defects are relocated by
avalanches whose size dependence on the external driving force $F$ is described
by a record-breaking process. We find that the depinning transition in this
model is a critical phenomenon, with the cumulative avalanche size diverging
near threshold as $(F_{\rm th} - F)^{-2}$. The exact avalanche size
distributions and their dependence on the control parameter $(F_{\rm th} - F)$
are obtained. Remarkably, the scaling exponents associated with the critical
behavior depend on (1) the initial conditions and (2) the relationship between
the system size and the pinning strength.


title:
Semi-classical, microscopic approach to the liquid drop model - a
  possible way of the description of heavy ion reaction

abstract:
  An isospin and spin dependent form of the equation of state for nuclear
matter is presented. This form is used for the description of nucleon
interaction in a new dynamic model. Preliminary calculations show that the new
approach makes possible predicting the alpha structures appearing in the case
of the ground state even-even nuclei.


title:
Does sequential augmenting of the simple linear heteroscedastic
  regression reduce variances of the Ordinary Least Squares?

abstract:
  If uncorrelated random variables have a common expected value and decreasing
variances then the variance of a sample mean is decreasing with the number of
observations. Unfortunately, this natural and desirable Variance Reduction
Property (VRP) by augmenting data is not automatically inherited by Ordinary
Least Squares (OLS) estimators of parameters.
  In the paper we find conditions for the OLS to have the VRP. In the case of a
straight line regression we show that the OLS estimators of intercept and slope
have the VRP if the design points are increasing. This also holds true for
alternating two-point experimental designs. The obtained results are useful in
the cases where it is known that variances of the subsequent observations are
non-increasing, but the ratios of the decrease are not available to use
sub-optimal or optimal Weighted Least Squares estimators.


title:
Analysis of Spontaneous Mass Generation by Iterative Method in the
  Nambu-Jona-Lasinio Model and Gauge Theories

abstract:
  We propose a new iterative method to directly calculate the spontaneous mass
generation due to the dynamical chiral symmetry breaking. We can conclude the
physical mass definitely without recourse to any other consideration like the
free energy comparison.


title:
The 7.1 hour X-ray-UV-NIR period of the gamma-ray classical Nova
  Monocerotis 2012

abstract:
  Nova Mon 2012 is the third gamma-ray transient identified with a
thermonuclear runaway on a white dwarf, that is, a nova event. Swift monitoring
has revealed the distinct evolution of the harder and super-soft X-ray spectral
components, while Swift-UV and V and I-band photometry show a gradual decline
with subtle changes of slope. During the super-soft emission phase, a coherent
7.1 hr modulation was found in the soft X-ray, UV, optical and near-IR data,
varying in phase across all wavebands. Assuming this period to be orbital, the
system has a near-main sequence secondary, with little appreciable stellar
wind. This distinguishes it from the first GeV nova, V407 Cyg, where the
gamma-rays were proposed to form through shock-accelerated particles as the
ejecta interacted with the red giant wind. We favor a model in which the
gamma-rays arise from the shock of the ejecta with material close to the white
dwarf in the orbital plane. This suggests that classical novae may commonly be
GeV sources. We ascribe the orbital modulation to a raised section of an
accretion disk passing through the line of sight, periodically blocking and
reflecting much of the emission. The disk must, therefore, have reformed by day
150 after outburst.


title: Entropy landscape of solutions in the binary perceptron problem

abstract:
  The statistical picture of the solution space for a binary perceptron is
studied. The binary perceptron learns a random classification of input random
patterns by a set of binary synaptic weights. The learning of this network is
difficult especially when the pattern (constraint) density is close to the
capacity, which is supposed to be intimately related to the structure of the
solution space. The geometrical organization is elucidated by the entropy
landscape from a reference configuration and of solution-pairs separated by a
given Hamming distance in the solution space. We evaluate the entropy at the
annealed level as well as replica symmetric level and the mean field result is
confirmed by the numerical simulations on single instances using the proposed
message passing algorithms. From the first landscape (a random configuration as
a reference), we see clearly how the solution space shrinks as more constraints
are added. From the second landscape of solution-pairs, we deduce the
coexistence of clustering and freezing in the solution space.


title: Ultra-Low Noise Multiwalled Carbon Nanotube Transistors

abstract:
  We report an experimental noise study of intermediate sized quasi ballistic
semiconducting multiwalled carbon nanotube (IS-MWCNT) devices. The noise is two
orders of magnitude lower than in singlewalled nanotubes (SWCNTs) and has no
length dependence within the studied range. In these channel limited devices
with small or negligible Schottky barriers the noise is shown to originate from
the intrinsic potential fluctuations of charge traps in the gate dielectric.
The gate dependence of normalized noise can be explained better using ballistic
the charge noise model rather than diffusive McWhorter model. The results
indicate that the noise properties of IS-MWCNTs are closer to SWCNTs than
thicker MWCNTs. These results can be utilized in future to analyze noise in
other purely ballistic nanoscale devices.


title:
Two particle correlation measurements with respect to higher harmonic
  event planes at PHENIX

abstract:
  Measurements of two particle azimuthal correlations in relativistic heavy ion
collisions provide information of the possible interplay between hard-scattered
partons and the hot-dense medium. Toward an understanding of parton-medium
coupling, it is indispensable to obtain correlations where contributions from
higher harmonic flow($v_n$) are rejected. It is also important to produce
correlation measurements where the trigger particle is selected relative to
second and third order event planes. This enables us to explore path-length
dependence of parton energy loss and the influence of the medium on the jets.
We present the latest PHENIX results of correlations in which contributions
from higher harmonic flow have been subtracted, as well as second and third
order event plane-dependent correlations in Au+Au collisions at
$\sqrt{s_{NN}}=200$ GeV.


title:
Half-Metallic Silicene and Germanene Nanoribbons: towards
  High-Performance Spintronics Device

abstract:
  By using first-principles calculations, we predict that an in-plane
homogenous electrical field can induce half-metallicity in hydrogen-terminated
zigzag silicene and germanene nanoribbons (ZSiNRs and ZGeNRs). A dual-gated
finite ZSiNR device reveals a nearly perfect spin-filter efficiency of up to
99% while a quadruple-gated finite ZSiNR device serves as an effective spin
field effect transistor (FET) with an on/off current ratio of over 100 from ab
initio quantum transport simulation. This discovery opens up novel prospect of
silicene and germanene in spintronics.


title:
Zero Temperature Phase Diagram of the Classical Kane-Mele-Heisenberg
  Model

abstract:
  The classical phase diagram of the Kane-Mele-Heisenberg model is obtained by
three complementary methods: Luttinger-Tisza, variational minimization, and the
iterative minimization method. Six distinct phases were obtained in the space
of the couplings. Three phases are commensurate with long-range ordering,
planar N{\'e}el states in horizontal plane (phase.I), planar states in the
plane vertical to the horizontal plane (phase.VI) and collinear states normal
to the horizontal plane (phase.II). However the other three, are infinitely
degenerate due to the frustrating competition between the couplings, and
characterized by a manifold of incommensurate wave-vectors. These phases are,
planar helical states in horizontal plane (phase.III), planar helical states in
a vertical plane (phase.IV) and non-coplanar states (phase.V). Employing the
linear spin-wave analysis, it is found that the quantum fluctuations select a
set of symmetrically equivalent states in phase.III, through the quantum
order-by-disorder mechanism. Based on some heuristic arguments is argued that
the same scenario may also occur in the other two frustrated phases VI and V.


title: Universal Lagrangian Bundles

abstract:
  The obstruction to construct a Lagrangian bundle over a fixed integral affine
manifold was constructed by Dazord and Delzant in \cite{daz_delz} and shown to
be given by `twisted' cup products in \cite{sepe_lag}. This paper uses the
topology of universal Lagrangian bundles, which classify Lagrangian bundles
topologically (cf. \cite{sepe_topc}), to reinterpret this obstruction as the
vanishing of a differential on the second page of a Leray-Serre spectral
sequence. Using this interpretation, it is shown that the obstruction of Dazord
and Delzant depends on an important cohomological invariant of the integral
affine structure on the base space, called the radiance obstruction, which was
introduced by Goldman and Hirsch in \cite{goldman}. Some examples, related to
non-degenerate singularities of completely integrable Hamiltonian systems, are
discussed.


title:
The single-mode description of the integer quantum Hall state with
  dipole-dipole interaction

abstract:
  A topological phase can often be represented by a corresponding wavefunction
(exact eigenstate of a model Hamiltonian) that has a higher underlying symmetry
than necessary. When the symmetry is explicitly broken in the Hamiltonian, the
model wavefunction fails to account for the change due to the lack of a
variational parameter. Here we exemplify the case by an integer quantum Hall
system with anisotropic interaction. We demonstrate the recovery of the
variational parameter in a single-mode approximation, which is consistent with
the recently proposed geometric consideration of the quantum Hall phases.


title: Optimum Phase Space Probabilities From Quantum Tomography

abstract:
  We determine a positive normalised phase space probability distribution $P$
with minimum mean square fractional deviation from the Wigner distribution $W$
.The minimum deviation, an invariant under phase space rotations, is a
quantitative measure of the quantumness of the state.The positive distribution
closest to $W$ will be useful in quantum mechanics and in time frequency
analysis .


title: New perspectives on Hawking radiation

abstract:
  We develop an adiabatic formalism to study the Hawking phenomenon from the
perspective of Unruh-DeWitt detectors moving along non-stationary,
non-asymptotic trajectories. When applied to geodesic trajectories, this
formalism yields the following results: (i) though they have zero acceleration,
the temperature measured by detectors on circular orbits is higher than that
measured by static detectors at the same distance from the hole, and diverges
on the photon sphere, (ii) in the near-horizon region, both outgoing and
incoming modes excite infalling detectors, and, for highly bound trajectories
(E<<1), the latter actually dominate the former. We confirm the apparent
perception of high-temperature Hawking radiation by infalling observers with
E<<1 by showing that the energy flux measured by these observers diverges in
the E->0 limit. We close by a discussion of the role played by spacetime
curvature on near-horizon Hawking radiation.


title: Lee, Han, and Kim Reply

abstract:
  In Letter [1], we reported our finding on the physical origin of wide
band-gap opening in planar nanostrips, as derived by application of periodic
width modulations in the magnetic waveguides. K. Di et al. in their Comment[2],
however, argued that the band gap can be reduced remarkably by applying a
linear combination of symmetric and antisymmetric fields (see 'A+B' in the
inset of Fig. 1(a)). They also insisted that they could find a complete set of
magnonic bands based on all of the mode symmetries. However, their work does
not constitute grounds for judging our method "wrong" and our conclusions
"erroneous". Moreover, the excitation field alluded to in the Comment is not
sufficiently general to obtain the complete set of magnonic band structures,
but rather remains specific. The grounds of these conclusions, drawn from our
further work, are the following.


title: 2-Stack Sorting is polynomial

abstract:
  In this article, we give a polynomial algorithm to decide whether a given
permutation $\sigma$ is sortable with two stacks in series. This is indeed a
longstanding open problem which was first introduced by Knuth. He introduced
the stack sorting problem as well as permutation patterns which arises
naturally when characterizing permutations that can be sorted with one stack.
When several stacks in series are considered, few results are known. There are
two main different problems. The first one is the complexity of deciding if a
permutation is sortable or not, the second one being the characterization and
the enumeration of those sortable permutations. We hereby prove that the first
problem lies in P by giving a polynomial algorithm to solve it. This article
strongly relies on a previous article in which 2-stack pushall sorting is
defined and studied.


title: Dirac equation with a magnetic field in 3D non-commutative phase space

abstract:
  For a spin-1/2 particle moving in a background magnetic field in
noncommutative phase space, Dirac equation is solved when the particle is
allowed to move off the plane that the magnetic field is perpendicular to. It
is shown that the motion of the charged particle along the magnetic field has
the effect to increase the magnetic field. In the classical limit, matrix
elements of the velocity operator related to the probability give a clear
physical picture: Along an effective magnetic field the mechanical momentum is
conserved and the motion perpendicular to the effective magnetic field follows
a round orbit. If using the velocity operator defined by the coordinate
operators, the motion becomes complicated.


title: Complements of nearly perfect graphs

abstract:
  A class of graphs closed under taking induced subgraphs is $\chi$-bounded if
there exists a function $f$ such that for all graphs $G$ in the class, $\chi(G)
\leq f(\omega(G))$. We consider the following question initially studied in [A.
Gy{\'a}rf{\'a}s, Problems from the world surrounding perfect graphs, {\em
Zastowania Matematyki Applicationes Mathematicae}, 19:413--441, 1987]. For a
$\chi$-bounded class $\cal C$, is the class $\bar{C}$ $\chi$-bounded (where
$\bar{\cal C}$ is the class of graphs formed by the complements of graphs from
$\cal C$)? We show that if $\cal C$ is $\chi$-bounded by the constant function
$f(x)=3$, then $\bar{\cal C}$ is $\chi$-bounded by
$g(x)=\lfloor\frac{8}{5}x\rfloor$ and this is best possible. We show that for
every constant $c>0$, if $\cal C$ is $\chi$-bounded by a function $f$ such that
$f(x)=x$ for $x \geq c$, then $\bar{\cal C}$ is $\chi$-bounded. For every $j$,
we construct a class of graphs $\chi$-bounded by $f(x)=x+x/\log^j(x)$ whose
complement is not $\chi$-bounded.


title:
Assessment of stochastic and deterministic models of 6304 quasar
  lightcurves from SDSS Stripe 82

abstract:
  The optical light curves of many quasars show variations of tenths of a
magnitude or more on time scales of months to years. This variation often
cannot be described well by a simple deterministic model. We perform a Bayesian
comparison of over 20 deterministic and stochastic models on 6304 QSO light
curves in SDSS Stripe 82. We include the damped random walk (or
Ornstein-Uhlenbeck [OU] process), a particular type of stochastic model which
recent studies have focused on. Further models we consider are single and
double sinusoids, multiple OU processes, higher order continuous autoregressive
processes, and composite models. We find that only 29 out of 6304 QSO
lightcurves are described significantly better by a deterministic model than a
stochastic one. The OU process is an adequate description of the vast majority
of cases (6023). Indeed, the OU process is the best single model for 3462 light
curves, with the composite OU process/sinusoid model being the best in 1706
cases. The latter model is the dominant one for brighter/bluer QSOs.
Furthermore, a non-negligible fraction of QSO lightcurves show evidence that
not only the mean is stochastic but the variance is stochastic, too. Our
results confirm earlier work that QSO light curves can be described with a
stochastic model, but place this on a firmer footing, and further show that the
OU process is preferred over several other stochastic and deterministic models.
Of course, there may well exist yet better (deterministic or stochastic) models
which have not been considered here.


title: Steady entanglement out of thermal equilibrium

abstract:
  We study two two-level atomic quantum systems (qubits) placed close to a body
held at a temperature different from that of the surrounding walls. While at
thermal equilibrium the two-qubit dynamics is characterized by not entangled
steady thermal states, we show that absence of thermal equilibrium may bring to
the generation of entangled steady states. Remarkably, this entanglement
emerges from the two-qubit dissipative dynamic itself, without any further
external action on the two qubits, suggesting a new protocol to produce and
protect entanglement which is intrinsically robust to environmental effects.


title:
The BOSARIS Toolkit: Theory, Algorithms and Code for Surviving the New
  DCF

abstract:
  The change of two orders of magnitude in the 'new DCF' of NIST's SRE'10,
relative to the 'old DCF' evaluation criterion, posed a difficult challenge for
participants and evaluator alike. Initially, participants were at a loss as to
how to calibrate their systems, while the evaluator underestimated the required
number of evaluation trials. After the fact, it is now obvious that both
calibration and evaluation require very large sets of trials. This poses the
challenges of (i) how to decide what number of trials is enough, and (ii) how
to process such large data sets with reasonable memory and CPU requirements.
After SRE'10, at the BOSARIS Workshop, we built solutions to these problems
into the freely available BOSARIS Toolkit. This paper explains the principles
and algorithms behind this toolkit. The main contributions of the toolkit are:
1. The Normalized Bayes Error-Rate Plot, which analyses likelihood- ratio
calibration over a wide range of DCF operating points. These plots also help in
judging the adequacy of the sizes of calibration and evaluation databases. 2.
Efficient algorithms to compute DCF and minDCF for large score files, over the
range of operating points required by these plots. 3. A new score file format,
which facilitates working with very large trial lists. 4. A faster logistic
regression optimizer for fusion and calibration. 5. A principled way to define
EER (equal error rate), which is of practical interest when the absolute error
count is small.


title:
Normal state bottleneck and nematic fluctuations from femtosecond
  quasi-particle relaxation dynamics in Sm(Fe,Co)AsO

abstract:
  We investigate temperature and fluence dependent dynamics of the photoexcited
quasi-particle relaxation and low-energy electronic structure in electron-doped
1111-structure Sm(Fe_{0.93}Co_{0.07})AsO single crystal. We find that the
behavior is qualitatively identical to the 122-structure Ba(Fe,Co)_{2}As_{2}
including the presence of a normal state pseudogap and a marked 2-fold symmetry
breaking in the tetragonal phase that we relate to the electronic nematicity.
The 2-fold symmetry breaking appears to be a general feature of the electron
doped iron pnictides.


title:
Guidelines to the Problem of Location Management and Database
  Architecture for the Next Generation Mobile Networks

abstract:
  In near future, anticipated large number of mobile users may introduce very
large centralized databases and increase end-to-end delays in location
registration and call delivery on HLR-VLR database and will become infeasible.
After observing several problems we propose some guidelines. Multitree
distributed database, high throughput index structure, memory oriented database
organization are used. Location management guidelines for moving user in
overlapping network, neighbor discovery protocol (NDP), and global roaming rule
are adopted. Analytic model and examples are presented to evaluate the
efficiency of proposed guidelines.


title:
Restriction to symmetric subgroups of unitary representations of rank
  one semisimple Lie groups

abstract:
  We consider the spherical complementary series of rank one Lie groups
$H_n=\SO_0(n, 1; \mathbb F)$ for $\mathbb F=\mathbb R, \mathbb C, \mathbb H$.
We prove that there exist finitely many discrete components in its restriction
under the subgroup $H_{n-1}=\SO_0(n-1, 1; \mathbb F)$. This is proved by
imbedding the complementary series into analytic continuation of holomorphic
discrete series of $G_n=SU(n, 1)$, $SU(n, 1)\times SU(n, 1)$ and $SU(2n, 2)$
and by the branching of holomorphic representations under the corresponding
subgroup
  $G_{n-1}$.


title: Global small solutions to three-dimensional incompressible MHD system

abstract:
  In this paper, we consider the global wellposedness of 3-D incompressible
magneto-hydrodynamical system with small and smooth initial data. The main
difficulty of the proof lies in establishing the global in time $L^1$ estimate
for the velocity field due to the strong degeneracy and anisotropic spectral
properties of the linearized system. To achieve this and to avoid the
difficulty of propagating anisotropic regularity for the transport equation, we
first write our system \eqref{B1} in the Lagrangian formulation \eqref{B11}.
Then we employ anisotropic Littlewood-Paley analysis to establish the key $L^1$
in time estimates to the velocity and the gradient of the pressure in the
Lagrangian coordinate. With those estimates, we prove the global wellposedness
of \eqref{B11} with smooth and small initial data by using the energy method.
Toward this, we will have to use the algebraic structure of \eqref{B11} in a
rather crucial way. The global wellposedness of the original system \eqref{B1}
then follows by a suitable change of variables together with a continuous
argument. We should point out that compared with the linearized systems of 2-D
MHD equations in \cite{XLZMHD1} and that of the 3-D modified MHD equations in
\cite{LZ}, our linearized system \eqref{B19} here is much more degenerate,
moreover, the formulation of the initial data for \eqref{B11} is more subtle
than that in \cite{XLZMHD1}.


title:
Single-hole tunneling through a two-dimensional hole gas in intrinsic
  silicon

abstract:
  In this letter we report single-hole tunneling through a quantum dot in a
two-dimensional hole gas, situated in a narrow-channel field-effect transistor
in intrinsic silicon. Two layers of aluminum gate electrodes are defined on
Si/SiO$_2$ using electron-beam lithography. Fabrication and subsequent
electrical characterization of different devices yield reproducible results,
such as typical MOSFET turn-on and pinch-off characteristics. Additionally,
linear transport measurements at 4 K result in regularly spaced Coulomb
oscillations, corresponding to single-hole tunneling through individual Coulomb
islands. These Coulomb peaks are visible over a broad range in gate voltage,
indicating very stable device operation. Energy spectroscopy measurements show
closed Coulomb diamonds with single-hole charging energies of 5--10 meV, and
lines of increased conductance as a result of resonant tunneling through
additional available hole states.


title: Single Hole Transport in a Silicon Metal-Oxide-Semiconductor Quantum Dot

abstract:
  We describe a planar silicon metal-oxide-semiconductor (MOS) based single
hole transistor, which is compatible with conventional Si CMOS fabrication. A
multi-layer gate design gives independent control of the carrier density in the
dot and reservoirs. Clear Coulomb blockade oscillations are observed, and
source-drain biasing measurements show that it is possible to deplete the dot
down to the few hole regime, with excited states clearly visible. The
architecture is sufficiently versatile that a second hole dot could be induced
adjacent to the first one.


title: Super-resolution image transfer by a vortex-like metamaterial

abstract:
  We propose a vortex-like metamaterial device that is capable of transferring
image along a spiral route without losing subwavelength information of the
image. The super-resolution image can be guided and magnified at the same time
with one single design. Our design may provide insights in manipulating
super-resolution image in a more flexible manner. Examples are given and
illustrated with numerical simulations.


title: Mask Effects on Cosmological Studies with Weak Lensing Peak Statistics

abstract:
  In this paper, we analyze in detail with numerical simulations how the mask
effect can influence the weak lensing peak statistics reconstructed from the
shear measurement of background galaxies. It is found that high peak fractions
are systematically enhanced due to masks, the larger the masked area, the
higher the enhancement. In the case with about $13\%$ of the total masked area,
the fraction of peaks with SNR $\nu\ge 3$ is $\sim 11\%$ in comparison with
$\sim 7\%$ of the mask-free case in our considered cosmological model. This can
induce a large bias on cosmological studies with weak lensing peak statistics.
Even for a survey area of $9\hbox{ deg}^2$, the bias in $(\Omega_m, \sigma_8)$
is already close to $3\sigma$. It is noted that most of the affected peaks are
close to the masked regions. Therefore excluding peaks in those regions can
reduce the bias but at the expense of loosing usable survey areas. Further
investigations find that the enhancement of high peaks number can be largely
attributed to higher noise led by the fewer number of galaxies usable in the
reconstruction. Based on Fan et al. (2010), we develop a model in which we
exclude only those large masks with radius larger than $3\arcmin. For the
remained part, we treat the areas close to and away from the masked regions
separately with different noise levels. It is shown that this two-noise-level
model can account for the mask effect on peak statistics very well and the
cosmological bias is significantly reduced.


title: Spectrum of stochastic adding machines and fibered Julia sets

abstract:
  Consider the basic algorithm to perform the transformation n--> n+1 changing
digits of the d-adic expansion of n one by one. We obtain a family of Markov
chains on the non-negative integers through sucessive and independent
applications of the algorithm modified by a parametrized stochastic rule that
randomly prevents one of the steps in the algorithm to finish. The objects of
study in this paper are the spectra of the transition operators of these Markov
chains. The spectra of these Markov chains turn out to be fibered Julia sets of
fibered polynomials. This enable us to analyze their topological and analytical
properties with respect to the underlying parameters of the Markov chains.


title: Confinement Stabilizes a Bacterial Suspension into a Spiral Vortex

abstract:
  Confining surfaces play crucial roles in dynamics, transport and order in
many physical systems, but their effects on active matter, a broad class of
dynamically self-organizing systems, are poorly understood. We investigate here
the influence of global confinement and surface curvature on collective motion
by studying the flow and orientational order within small droplets of a dense
bacterial suspension. The competition between radial confinement,
self-propulsion, steric interactions and hydrodynamics robustly induces an
intriguing steady single-vortex state, in which cells align in
inwardly-spiralling patterns accompanied by a thin counterrotating boundary
layer. A minimal continuum model is shown to be in good agreement with these
observations.


title:
Detailed HBT measurements with respect to the event plane and collision
  energy in Au+Au collisions at PHENIX

abstract:
  The azimuthal dependence of 3D HBT radii relative to the event plane gives us
information about the source shape at freeze-out. It also provides information
on the system's evolution by comparing it to the initial source shape. In
recent studies, higher harmonic event planes and flow have been measured at
RHIC and the LHC, which result primarily from spatial fluctuations of the
initial density across the collision area. If the shape caused by initial
fluctuations still exists at freeze-out, the HBT measurement relative to higher
order event plane may show these features.
  We present recent results of azimuthal HBT measurements relative to $2^{nd}$-
and $3^{rd}$-order event planes in Au+Au 200 GeV collisions with the PHENIX
experiment. Recent HBT measurements at lower energies will be also shown and
compared with the 200 GeV result.


title:
Evidence of two distinct local structures of water from ambient to
  supercooled conditions

abstract:
  The liquid and supercooled states of water show a series of anomalies whose
nature is debated. A key role is attributed to the formation of structural
aggregates induced by critical phenomena occurring deep in the supercooled
region; the nature of the water anomalies and of the hidden critical processes
remains elusive. Here we report a time-resolved optical Kerr effect
investigation of the vibrational dynamics and relaxation processes in
supercooled bulk water. The experiment measures the water intermolecular
vibrations and the structural relaxation process in an extended temperature
range, and with unprecedented data quality. A mode-coupling analysis of the
experimental data enables to characterize the intermolecular vibrational modes
and their interplay with the structural relaxation process. The results bring
evidence of the coexistence of two local configurations, which are interpreted
as high-density and low-density water forms, with an increasing weight of the
latter at low temperatures.


title:
Fermi LAT detection of extraordinary variability in the gamma-ray
  emission of the blazar PKS 1510-089

abstract:
  We have reanalyzed the giant outburst of the blazar PKS 1510-089 (z=0.36)
that occurred on 2011 October-November. The gamma-ray flux in the 0.1-100 GeV
energy range exceeded the value of 10^-5 ph/cm2/s for several days. The peak
flux was reached on 2011 October 19, with a value of 4.4 x 10^-5 ph/cm2/s,
which in turn corresponds to a luminosity of 2 x 10^49 erg/s. A very short
timescale variability was measured. Particularly on 2011 October 18, the
flux-doubling time was as short as 20 minutes. This is the shortest variability
ever detected in the MeV-GeV energy band. We compared our analysis with two
other outbursts observed in 2009 March and 2012 February-March, when the blazar
was also detected by HESS and MAGIC to infer information about the emission at
hundreds of GeV.


title:
Ising models and topological codes: classical algorithms and quantum
  simulation

abstract:
  We present an algorithm to approximate partition functions of 3-body
classical Ising models on two-dimensional lattices of arbitrary genus, in the
real-temperature regime. Even though our algorithm is purely classical, it is
designed by exploiting a connection to topological quantum systems, namely the
color codes. The algorithm performance is exponentially better than other
approaches which employ mappings between partition functions and quantum state
overlaps. In addition, our approach gives rise to a protocol for quantum
simulation of such Ising models by simply measuring local observables on color
codes.

categories: quant-ph cond-mat.stat-mech cond-mat.str-el hep-th


title: Dunkl positive definite functions

abstract:
  We introduce the notion of Dunkl positive definite and strictly positive
definite functions on $\mathbb{R}^{d}$. This done by the use of the properties
of Dunkl translation. We establish the analogue of Bochner's theorem in Dunkl
setting. The case of radial functions is considered. We give a sufficient
condition for a function to be Dunkl strictly positive definite on
$\mathbb{R}^{d}.$


title: Balanced offline allocation of weighted balls into bins

abstract:
  We propose a sorting-based greedy algorithm called SortedGreedy[m] for
approximately solving the offline version of the d-choice weighted
balls-into-bins problem where the number of choices for each ball is equal to
the number of bins. We assume the ball weights to be non-negative. We compare
the performance of the sorting-based algorithm with a naive algorithm called
Greedy[m]. We show that by sorting the input data according to the weights we
are able to achieve an order of magnitude smaller gap (the weight difference
between the heaviest and the lightest bin) for small problems (<= 4000 balls),
and at least two orders of magnitude smaller gap for larger problems. In
practice, SortedGreedy[m] runs almost as fast as Greedy[m]. This makes
sorting-based algorithms favorable for solving offline weighted balls-into-bins
problems.


title: Electromagnetic Structure of the Z_c(3900)

abstract:
  The observation of the exotic quarkonium state Z_c(3900) by the BESIII and
Belle collaborations supports the concept of hadronic molecules. Charmonium
states interpreted as such molecules would be bound states of heavy particles
with small binding energies. This motivates their description using an
effective theory with contact interactions. In particular, we focus on the
electromagnetic structure of the charged state Z_c(3900). Using first
experimental results concerning spin and parity, we interpret it as an S-wave
molecule and calculate the form factors as well as charge and magnetic radii up
to next-to-leading order. We also present first numerical estimations of some
of these observables at leading order.


title:
Recovering partial conservation of axial current in diffractive neutrino
  scattering

abstract:
  A model of diffractive neutrino scattering is formulated in terms of the
chiral hadronic current which is conserved in the limit of vanishing pion mass.
This current has the correct singularity structure and, naturally, does not
lead to contradictions with a partial conservation of the axial current (PCAC).
In that respect we differ from earlier work in the literature, where a
breakdown of PCAC had been reported. We show that such a breakdown of PCAC is
an artifact of the hadronic current non-conservation in the model developed
there.


title:
Evidence for a ~300 Mpc Scale Under-density in the Local Galaxy
  Distribution

abstract:
  Galaxy counts and recent measurements of the luminosity density in the
near-infrared (NIR) have indicated the possibility that the local universe may
be under-dense on scales of several hundred megaparsecs. The presence of a
large-scale under-density in the local universe could introduce significant
biases into the interpretation of cosmological observables, and, in particular,
into the inferred effects of dark energy on the expansion rate. Here we measure
the K-band luminosity density as a function of redshift to test for such a
local under-density. In this effort, we combine photometry from UKIDSS and
2MASS with redshifts from the SDSS, 2DFGRS, 6DFGRS, 2MR, and GAMA surveys. We
find that the overall shape of the z=0 rest-frame K-band luminosity function
(M* = -22.15 +/- 0.04 and alpha = -1.02 +/- 0.03) appears to be relatively
constant as a function of environment and redshift out to z ~0.2. We find a
local (z < 0.07) luminosity density that is in good agreement with previous
studies. Beyond z ~ 0.07 we detect a rising luminosity density that reaches a
value ~1.5 times higher than that measured locally at z>0.1. This suggests that
the stellar mass density as a function of redshift follows a similar trend.
Assuming that luminous matter traces the underlying dark matter distribution,
this implies that the local mass density of the universe may be lower than the
global value on a scale and amplitude sufficient to introduce significant
biases into the determination of basic cosmological observables, such as the
expansion rate. An under-density of roughly this scale and amplitude would be
sufficient to resolve the apparent tension between direct measurements of the
Hubble constant and those inferred by Planck.


title:
Modeling double slit interference via anomalous diffusion: independently
  variable slit widths

abstract:
  Based on a re-formulation of the classical explanation of quantum mechanical
Gaussian dispersion (Groessing et al. 2010) as well as interference of two
Gaussians (Groessing et al. 2012), we present a new and more practical way of
their simulation. The quantum mechanical "decay of the wave packet" can be
described by anomalous sub-quantum diffusion with a specific diffusivity
varying in time due to a particle's changing thermal environment. In a
simulation of the double-slit experiment with different slit widths, the phase
with this new approach can be implemented as a local quantity. We describe the
conditions of the diffusivity and, by connecting to wave mechanics, we compute
the exact quantum mechanical intensity distributions, as well as the
corresponding trajectory distributions according to the velocity field of two
Gaussian wave packets emerging from a double-slit. We also calculate
probability density current distributions, including situations where phase
shifters affect a single slit's current, and provide computer simulations
thereof.


title:
Resonant states of H$_3^-$ molecule and its isotopologues D$_2$H$^-$ and
  H$_2$D$^-$

abstract:
  Using the ground potential energy surface[M. Ayouz \textit{et\, al}. J. Chem
Phys \textbf{132} 194309 (2010)] of the H$_3^-$ molecule, we have determined
the energies and widths of the complex resonant levels of H$_3^-$ located up to
4000 cm$^{-1}$ above the dissociation limit H$^-$+H$_2(v_d=0,j_d=0)$. Bound and
resonant levels of the H$_2$D$^-$ and D$_2$H$^-$ isotopologues have been also
characterized within the same energy range. The method combines the
hyperspherical adiabatic approach, slow variable discretization method, and
complex absorbing potential. These results represent the first step for
modeling the dynamics of the associated diatom-negative ion collision at low
energy involving rotational quenching of the diatom and reactive nucleus
exchange via weak tunneling effect through the potential barrier of the
potential energy surface.


title:
Entanglement measure using Wigner function: case of generalized vortex
  state formed by multiphoton subtraction

abstract:
  The negativity of the Wigner function is discussed as a measure of the non
classicality and the quantum interference pattern obtained therein as a
possible measure of the entanglement between the two modes of the vortex
states. This measure of entanglement is compared with the results obtained from
concurrence.


title: Roborobo! a Fast Robot Simulator for Swarm and Collective Robotics

abstract:
  Roborobo! is a multi-platform, highly portable, robot simulator for
large-scale collective robotics experiments. Roborobo! is coded in C++, and
follows the KISS guideline ("Keep it simple"). Therefore, its external
dependency is solely limited to the widely available SDL library for fast 2D
Graphics. Roborobo! is based on a Khepera/ePuck model. It is targeted for fast
single and multi-robots simulation, and has already been used in more than a
dozen published research mainly concerned with evolutionary swarm robotics,
including environment-driven self-adaptation and distributed evolutionary
optimization, as well as online onboard embodied evolution and embodied
morphogenesis.


title: Glyph Sorting: Interactive Visualization for Multi-dimensional Data

abstract:
  Glyph-based visualization is an effective tool for depicting multivariate
information. Since sorting is one of the most common analytical tasks performed
on individual attributes of a multi-dimensional data set, this motivates the
hypothesis that introducing glyph sorting would significantly enhance the
usability of glyph-based visualization. In this paper, we present a glyph-based
conceptual framework as part of a visualization process for interactive sorting
of multivariate data. We examine several technical aspects of glyph sorting and
provide design principles for developing effective, visually sortable glyphs.
Glyphs that are visually sortable provide two key benefits: 1) performing
comparative analysis of multiple attributes between glyphs and 2) to support
multi-dimensional visual search. We describe a system that incorporates focus
and context glyphs to control sorting in a visually intuitive manner and for
viewing sorted results in an Interactive, Multi-dimensional Glyph (IMG) plot
that enables users to perform high-dimensional sorting, analyse and examine
data trends in detail. To demonstrate the usability of glyph sorting, we
present a case study in rugby event analysis for comparing and analysing trends
within matches. This work is undertaken in conjunction with a national rugby
team. From using glyph sorting, analysts have reported the discovery of new
insight beyond traditional match analysis.


title: Heavy water stratification in a low-mass protostar

abstract:
  Context: Despite the low elemental deuterium abundance in the Galaxy,
enhanced molecular D/H ratios have been found in the environments of low-mass
star-forming regions and, in particular, the Class 0 protostar IRAS 16293-2422.
Aims: The key program Chemical HErschel Surveys of Star forming regions (CHESS)
aims at studying the molecular complexity of the interstellar medium. The high
sensitivity and spectral resolution of the Herschel/HIFI instrument provide a
unique opportunity to observe the fundamental 1_{1,1}-0_{0,0} transition of
ortho-D2O at 607 GHz and the higher energy 2_{1,2}-1_{0,1} transition of
para-D2O at 898 GHz, both of which are inaccessible from the ground. Methods:
The ortho-D2O transition at 607 GHz was previously detected. We present in this
paper the first tentative detection for the para-D2O transition at 898 GHz. The
spherical Monte Carlo radiative transfer code RATRAN was used to reproduce the
observed line profiles of D2O with the same method that was used to reproduce
the HDO and H2-18O line profiles in IRAS 16293-2422. Results: As for HDO, the
absorption component seen on the D2O lines can only be reproduced by adding an
external absorbing layer, possibly created by the photodesorption of the ices
at the edges of the molecular cloud. The D2O column density is found to be
about 2.5e12 cm^{-2} in this added layer, leading to a D2O/H2O ratio of about
0.5%. At a 3 sigma uncertainty, upper limits of 0.03% and 0.2% are obtained for
this ratio in the hot corino and the colder envelope of IRAS 16293-2422,
respectively. Conclusions: The deuterium fractionation derived in our study
suggests that the ices present in IRAS 16293-2422 formed on warm dust grains
(~15-20 K) in dense (~1e4-5e4 cm^{-3}) translucent clouds. These results allow
us to address the earliest phases of star formation and the conditions in which
ices form.


title: Short-distance properties of Coulomb systems

abstract:
  We use the operator product expansion to derive exact results for the
momentum distribution and the static structure factor at high momentum for a
jellium model of electrons in both two and three dimensions. It is shown that
independent of the precise state of the Coulomb system and for arbitrary
temperatures, the asymptotic behavior is a power law in the momentum, whose
strength is determined by the contact value of the pair distribution function
$g(0)$. The power-law tails are quantum effects which vanish in the classical
limit $\hbar \to 0$. A leading order virial expansion shows that the classical
and the high-temperature limit do not agree.


title: Fibonacci system and residue completeness

abstract:
  We give necessary and sufficient conditions for a Fibonacci cycle to be
residue complete (nondefective). In particular, the Lucas numbers modulo m is
residue complete if and only if m = 2,4,6,7,14 or a power of 3.


title:
On embeddability of automorphisms into measurable flows from the point
  of view of self-joining properties

abstract:
  We compare self-joining- and embeddability properties. In particular, we
prove that a measure preserving flow $(T_t)_{t\in\mathbb{R}}$ with $T_1$
ergodic is 2-fold quasi-simple (2-fold distally simple) if and only if $T_1$ is
2-fold quasi-simple (2-fold distally simple). We also show that the
Furstenberg-Zimmer decomposition for a flow $(T_t)_{t\in\mathbb{R}}$ with $T_1$
ergodic with respect to any flow factor is the same for
$(T_t)_{t\in\mathbb{R}}$ and for $T_1$. We give an example of a 2-fold
quasi-simple flow disjoint from simple flows and whose time-one map is simple.
We describe two classes of flows (flows with minimal self-joining property and
flows with the so-called Ratner property) whose time-one maps have unique
embeddings into measurable flows. We also give an example of a 2-fold simple
flow whose time-one map has more than one embedding.


title:
A Data Acquisition and Monitoring System for the Detector Development
  Group at FZJ/ZEA-2

abstract:
  The central institute of electronics (ZEA-2) in the Forschungszentrum Juelich
(FZJ) has developed the novel readout electronics JUDIDT to cope with high-rate
data acquisition of the KWS-1 and KWS-2 detectors in the experimental Hall at
the Forschungsreacktor Muenchen FRM-II in Garching, Muenchen. This electronics
has been then modified and used also for the data-acquisition of a prototype
for an ANGER Camera proposed for the planned European Spallation Source. To
commission the electronics, software for the data acquisition and the data
monitoring has been developed. In this report the software is described.


title: Where to Find Habitable "Earths" in Circumbinary Systems

abstract:
  Hitherto, six P-type planets are found around five binary systems, i.e.
Kepler-16 b, 34 b, 35 b, 38 b, 47 b, c, which are all Neptune or Jupiter-like
planets. The stability of planets and the habitable zones are influenced by the
gravitational and radiative perturbations of binary companions. In this Letter,
we check the stability of an additional habitable Earth-mass planet in each
system. Based on our simulations in 10 Myr, a habitable "Earth" is hardly
stable in Kepler-16 while a stable "Earth" in Kepler-47 close to the boundaries
of the habitable zone is possible. In contrast, Kepler-34, 35 and 38 seem to
have high probabilities of being able to tolerate a stable "Earth" in their
habitable zones. The affects of transit time variations are quite small due to
the small mass of an undetected "Earth", except that of Kepler-16 b. With a
time precision of 0.001 day(~ 88 s), an "Earth" in the corotational resonance
with Kepler-16 b can be detected in 3 years, while habitable "Earths" in
Kepler-34 and 38 systems can be detected in 10 years. Habitable "Earths" in
Kepler-35 and 47 are not likely to be detected in 10 years under this
precision.


title: Using hierarchical octrees in Monte Carlo radiative transfer simulations

abstract:
  A crucial aspect of 3D Monte Carlo radiative transfer is the choice of the
spatial grid used to partition the dusty medium. We critically investigate the
use of octree grids in Monte Carlo dust radiative transfer, with two different
octree construction algorithms (regular and barycentric subdivision) and three
different octree traversal algorithms (top-down, neighbour list, and the
bookkeeping method). In general, regular octree grids need higher levels of
subdivision compared to the barycentric grids for a fixed maximum cell mass
threshold criterion. The total number of grid cells, however, depends on the
geometry of the model. Surprisingly, regular octree grid simulations turn out
to be 10 to 20% more efficient in run time than the barycentric grid
simulations, even for those cases where the latter contain fewer grid cells
than the former. Furthermore, we find that storing neighbour lists for each
cell in an octree, ordered according to decreasing overlap area, is worth the
additional memory and implementation overhead: using neighbour lists can cut
down the grid traversal by 20% compared to the traditional top-down method. In
conclusion, the combination of a regular node subdivision and the neighbour
list method results in the most efficient octree structure for Monte Carlo
radiative transfer simulations.


title:
Nuclear in-medium and isospin effects on subthreshold kaon production in
  heavy-ion collisions

abstract:
  Subthreshold kaon (K$^{0}$ and K$^{+}$) production in neutron-rich nuclear
reactions to probe the kaon-nucleon interaction in nuclear medium and to
extract the isospin dependent part of the nuclear equation of state at
high-baryon densities, is investigated within an isospin and momentum dependent
transport model. A repulsive kaon-nucleon potential is implemented in the model
through fitting the flow data and inclusive spectra in heavy-ion collisions,
which enhances the energetic kaon emission squeezed out in the reaction zone
and leads to a variation of the high-momentum spectrum of the K$^{0}$/K$^{+}$
yields. It is found that the stiffness of nuclear symmetry energy plays a
significant role on the isospin ratio with decreasing the incident energy and a
hard symmetry energy has a larger value of the K$^{0}$/K$^{+}$ ratio in the
domain of subthreshold energies.


title: Design and development of the CSNS ion source control system

abstract:
  After the CSNS ion source test stand has been stably working for years, an
online control system for CSNS ion source aiming to be more stable and reliable
is now under development. F3RP61-2L, a new PLC CPU module under Linux system,
is introduced to the system as an IOC, to function together with the I/O
modules of FA-M3 PLC on the PLC-bus. The adoption of the new IOC not only
simplifies the architecture of the control system, but also improves the data
transmission speed. In this paper, the design and development of the
supervisory and control system for CSNS ion source are described.


title: Microwave induced elastic deformation of a metallic thin film

abstract:
  The microwave induced elastic deformation of a metallic thin film is computed
numerically and we found that the deformation can be significantly enhanced at
resonance. We show that an analytical transmission line model can reproduce the
numerical results almost quantitatively and at the same time reveal the
underlying physics.


title:
Microwave transmissions through superconducting coplanar waveguide
  resonators with different coupling configurations

abstract:
  We design and fabricate two types of superconducting niobium coplanar
waveguide microwave resonators with different coupling capacitors on high
purity Si substrates. Their microwave transmissions are measured at the
temperatures of 20 mK. It is found that these two types of resonators possess
significantly-different loaded quality factors; one is $5.6\times{10}^{3}$, and
the other is $4.0\times{10}^{4}$. The measured data are fitted well by
classical ABCD matrix approach. We found that the transmission peak deviates
from the standard Lorentizian with a frequency broadening.


title:
Constraints on the Sunyaev-Zel'dovich signal from the Warm Hot
  Intergalactic Medium from WMAP and SPT data

abstract:
  The fraction of ionized gas in the Warm Hot Intergalactic Medium induces
temperature anisotropies on the Cosmic Microwave Background similar to those of
clusters of galaxies. The Sunyaev-Zel'dovich anisotropies due to these low
density, weakly non-linear, baryon filaments can not be distinguished from that
of clusters using frequency information, but they can be separated since their
angular scales are very different. To determine the relative contribution of
the WHIM SZ signal to the radiation power spectrum of temperature anisotropies,
we explore the parameter space of the concordance LCDM model using Monte Carlo
Markov Chains and the Wilkinson Microwave Anisotropy Probe 7yr and South Pole
Telescope data. We find marginal evidence of a contribution by diffuse gas,
with amplitudes of A_WHIM=10-20 muK^2, but the results are also compatible with
a null contribution from the WHIM, allowing to set an upper limit of A_WHIM <
43 muK^2 (95.4% C.L.). The signal produced by galaxy clusters remains at
A_CL=4.5 muK^2, a value similar to what is obtained when no WHIM is included.
From the measured WHIM amplitude we constrain the temperature-density phase
diagram of the diffuse gas, and find it to be compatible with numerical
simulations. The corresponding baryon fraction in the WHIM varies from 0.43 to
0.47, depending on model parameters. Planck data could set tighter constraints
on the temperature-density relation.


title:
Random fields representations for stochastic elliptic boundary value
  problems and statistical inverse problems

abstract:
  This paper presents new results allowing an unknown non-Gaussian positive
matrix-valued random field to be identified through a stochastic elliptic
boundary value problem, solving a statistical inverse problem. A new general
class of non-Gaussian positive-definite matrix-valued random fields, adapted to
the statistical inverse problems in high stochastic dimension for their
experimental identification, is introduced and its properties are analyzed. A
minimal parametrization of discretized random fields belonging to this general
class is proposed. Using this parametrization of the general class, a complete
identification procedure is proposed. New results of the mathematical and
numerical analyzes of the parameterized stochastic elliptic boundary value
problem are presented. The numerical solution of this parametric stochastic
problem provides an explicit approximation of the application that maps the
parameterized general class of random fields to the corresponding set of random
solutions. This approximation can be used during the identification procedure
in order to avoid the solution of multiple forward stochastic problems. Since
the proposed general class of random fields possibly contains random fields
which are not uniformly bounded, a particular mathematical analysis is
developed and dedicated approximation methods are introduced. In order to
obtain an algorithm for constructing the approximation of a very
high-dimensional map, complexity reduction methods are introduced and are based
on the use of low-rank approximation methods that exploit the tensor structure
of the solution which results from the parametrization of the general class of
random fields.


title:
Totally dissipative dynamical processes and their uniform global
  attractors

abstract:
  We discuss the existence of the global attractor for a family of processes
$U_\sigma(t,\tau)$ acting on a metric space $X$ and depending on a symbol
$\sigma$ belonging to some other metric space $\Sigma$. Such an attractor is
uniform with respect to $\sigma\in\Sigma$, as well as with respect to the
choice of the initial time $\tau\in\R$. The existence of the attractor is
established for totally dissipative processes without any continuity
assumption. When the process satisfies some additional (but rather mild)
continuity-like hypotheses, a characterization of the attractor is given.


title:
On fundamental harmonic analysis operators in certain Dunkl and Bessel
  settings

abstract:
  We consider several harmonic analysis operators in the multi-dimensional
context of the Dunkl Laplacian with the underlying group of reflections
isomorphic to $\mathbb{Z}_2^n$ (also negative values of the multiplicity
function are admitted). Our investigations include maximal operators,
$g$-functions, Lusin area integrals, Riesz transforms and multipliers of
Laplace and Laplace-Stieltjes transform type. Using the general
Calder\'on-Zygmund theory we prove that these objects are bounded in weighted
$L^p$ spaces, $1<p<\infty$, and from $L^1$ into weak $L^{1}$.


title: Geometric aspects of 2-walk-regular graphs

abstract:
  A $t$-walk-regular graph is a graph for which the number of walks of given
length between two vertices depends only on the distance between these two
vertices, as long as this distance is at most $t$. Such graphs generalize
distance-regular graphs and $t$-arc-transitive graphs. In this paper, we will
focus on 1- and in particular 2-walk-regular graphs, and study analogues of
certain results that are important for distance regular graphs. We will
generalize Delsarte's clique bound to 1-walk-regular graphs, Godsil's
multiplicity bound and Terwilliger's analysis of the local structure to
2-walk-regular graphs. We will show that 2-walk-regular graphs have a much
richer combinatorial structure than 1-walk-regular graphs, for example by
proving that there are finitely many non-geometric 2-walk-regular graphs with
given smallest eigenvalue and given diameter (a geometric graph is the point
graph of a special partial linear space); a result that is analogous to a
result on distance-regular graphs. Such a result does not hold for
1-walk-regular graphs, as our construction methods will show.


title: Periodic representations for cubic irrationalities

abstract:
  In this paper we present some results related to the problem of finding
periodic representations for algebraic numbers. In particular, we analyze the
problem for cubic irrationalities. We show an interesting relationship between
the convergents of bifurcating continued fractions related to a couple of cubic
irrationalities, and a particular generalization of the Redei polynomials.
Moreover, we give a method to construct a periodic bifurcating continued
fraction for any cubic root paired with another determined cubic root.


title:
Flare-associated type III radio bursts and dynamics of the EUV jet from
  SDO/AIA and RHESSI observations

abstract:
  We present a detailed description of the interrelation between the Type III
radio bursts and energetic phenomena associated with the flare activities in
Active region AR 11158 at 07:58 UT on 2011, Feb. 15. The timing of the Type-III
radio burst measured by the radio wave experiment on the Wind/WAVE and an array
of ground-based radio telescopes, coincided with an EUV jet and hard X-ray
emission observed by SDO/AIA and RHESSI., respectively. There is clear evidence
that the EUV jet shares the same source region as the hard X-ray emission. The
temperature of the jet, as determined by multiwavelength measurements of AIA,
suggests that type III emission is associated with hot, 7 MK, plasma at the
jet's footpoint.


title: On the particle excitations in the XXZ- spin chain

abstract:
  We continue to study the excited states for the XXZ- spin chain corresponding
to the complex roots of the Bethe Ansatz equations with the imaginary part
equal to $\pi/2$. We propose the particle-hole symmetry which relates the
eigenstates build up from the two different pseudovacuum states. We find the
XXX- spin chain limit for the eigenstates with the complex roots. We also
comment on the low-energy excited states for the XXZ- spin chain.


title:
The Influence of Thermal Evolution in the Magnetic Protection of
  Terrestrial Planets

abstract:
  Magnetic protection of potentially habitable planets plays a central role in
determining their actual habitability and/or the chances of detecting
atmospheric biosignatures. We develop here a thermal evolution model of
potentially habitable Earth-like planets and super-Earths. Using up-to-date
dynamo scaling laws we predict the properties of core dynamo magnetic fields
and study the influence of thermal evolution on their properties. The level of
magnetic protection of tidally locked and unlocked planets is estimated by
combining simplified models of the planetary magnetosphere and a
phenomenological description of the stellar wind. Thermal evolution introduces
a strong dependence of magnetic protection on planetary mass and rotation rate.
Tidally locked terrestrial planets with an Earth-like composition would have
early dayside magnetospause distances between 1.5 and 4.0 Rp, larger than
previously estimated. Unlocked planets with periods of rotation ~1 day are
protected by magnetospheres extending between 3 and 8 Rp. Our results are
robust against variations in planetary bulk composition and uncertainties in
other critical model parameters. For illustration purposes the thermal
evolution and magnetic protection of the potentially habitable super-Earths GL
581d, GJ 667Cc and HD 40307g were also studied. Assuming an Earth-like
composition we found that the dynamos of these planets are already extinct or
close to being shut down. While GL 581d is the best protected, the protection
of HD 40307g cannot be reliably estimated. GJ 667Cc, even under optimistic
conditions, seems to be severely exposed to the stellar wind and, under the
conditions of our model, has probably suffered massive atmospheric losses.


title: Quantum replication at the Heisenberg limit

abstract:
  No process in nature can perfectly clone an arbitrary quantum state. But is
it possible to engineer processes that replicate quantum information with
vanishingly small error? Here we demonstrate the possibility of probabilistic
super-replication phenomena where N equally prepared quantum clocks are
transformed into a much larger number of M nearly perfect replicas, with an
error that rapidly vanishes whenever M is small compared to the square of N.
The quadratic replication rate is the ultimate limit imposed by Quantum
Mechanics to the proliferation of information and is fundamentally linked with
the Heisenberg limit of quantum metrology.


title:
Large room-temperature magnetoresistance in lateral organic spin valves
  fabricated by in-situ shadow evaporation

abstract:
  We report the successful fabrication of lateral organic spin valves with a
channel length in the sub $100\,nm$ regime. The fabication process is based on
in-situ shadow evaporation under UHV conditions and therefore yields clean and
oxygen-free interfaces between the ferromagnetic metallic electrodes and the
organic semiconductor. The spin valve devices consist of Nickel and Cobalt-iron
electrodes and the high mobility \emph{n}-type organic semiconductor
$N,N'$-bis(heptafluorobutyl)-$3,4:9,10$-perylene diimide. Our studies comprise
fundamental investigations of the process' and materials' suitability for the
fabrication of lateral spin valve devices as well as magnetotransport
measurements at room temperature. The best devices exhibit a magnetoresistance
of up to $50\,%$, the largest value for room temperature reported so far.


title: Demonstration of Weak Measurement Based on Atomic Spontaneous Emission

abstract:
  We demonstrate a new type of weak measurement based on the dynamics of
spontaneous emission. The pointer in our scheme is given by the Lorentzian
distribution characterizing atomic exponential decay via emission of a single
photon. We thus introduce weak measurement, so far demonstrated nearly
exclusively with laser beams and Gaussian statistics, into the quantum regime
of single emitters and single quanta, enabling the exploitation of a wide class
of sources that are abundant in nature. We describe a complete analogy between
our scheme and weak measurement with conventional Gaussian pointers. Instead of
a shift in the mean of a Gaussian distribution, an imaginary weak value is
exhibited in our scheme by a significantly slower-than-natural exponential
distribution of emitted photons at the postselected polarization, leading to a
large shift in their mean arrival time. The dynamics of spontaneous emission
offer a broader view of the measurement process than is usually considered
within the weak measurement formalism. Our scheme opens the path for the use of
atoms and atomlike systems as sensitive probes in weak measurements, one
example being optical magnetometry.


title: Grassmannian twists, derived equivalences and brane transport

abstract:
  This note is based on a talk given at String-Math 2012 in Bonn, on a joint
paper with Ed Segal. We exhibit derived equivalences corresponding to certain
Grassmannian flops. The construction of these equivalences is inspired by work
of Herbst-Hori-Page on brane transport for gauged linear sigma models: in
particular, we define 'windows' corresponding to their grade restriction rules.
We then show how composing our equivalences produces interesting
autoequivalences, which we describe as twists and cotwists about certain
spherical functors. Our proofs use natural long exact sequences of bundles on
Grassmannians known as twisted Lascoux complexes, or staircase complexes. We
give a compact description of these. We also touch on some related
developments, and work through some extended examples.


title: Quantum discord cannot be shared

abstract:
  Niels Bohr proposed that the outcome of the measurement becomes objective and
real, and, hence, classical, when its results can be communicated by classical
means. In this work we revisit Bohr's postulate using modern tools from the
quantum information theory. We find a full confirmation of Bohr's idea: if a
measurement device is in a nonclassical state, the measurement results cannot
be communicated perfectly by classical means. In this case some part of
information in the measurement apparatus is lost in the process of
communication: the amount of this lost information turns out to be the quantum
discord. The information loss occurs even when the apparatus is not entangled
with the system of interest. The tools presented in this work allow to
generalize Bohr's postulate: we show that for pure system-apparatus states
quantum communication does not provide any advantage when measurement results
are communicated to more than one recipient. We further demonstrate the
superiority of quantum communication to two recipients on a mixed
system-apparatus state and show that this effect is fundamentally different
from quantum state cloning.


title:
The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of
  Variable Stars. Type II Cepheids in the Galactic Bulge - Supplement

abstract:
  We report the discovery of additional 22 RV Tau stars located in the OGLE-II
and OGLE-III fields toward the Galactic bulge, increasing to 357 objects the
OGLE-III catalog of type II Cepheids in the Galactic center. Four of the newly
detected RV Tau stars belong to the RVb class, i.e. they show large-amplitude,
long-period modulation of the mean luminosity. In the updated catalog, the
relative number of RV Tau stars in the whole sample of the Galactic bulge type
II Cepheids is similar to the Magellanic Cloud samples.


title: Cosmological Solutions in Biconnection and Bimetric Gravity Theories

abstract:
  We show how generic off--diagonal cosmological solutions depending, in
general, on all spacetime coordinates can be constructed in massive gravity
using the anholonomic frame deformation method. Such metrics describe the late
time acceleration due to effective cosmological terms induced by nonlinear
off--diagonal interactions and graviton mass and include matter, graviton mass
and other effective sources modelling nonlinear gravitational and matter fields
interactions with polarization of physical constants and deformations of
metrics, which may explain certain dark energy and dark matter effects.


title:
MODULAR: Software for the Autonomous Computation of Modularity in Large
  Network Sets

abstract:
  Ecological systems can be seen as networks of interactions between
individual, species, or habitat patches. A key feature of many ecological
networks is their organization into modules, which are subsets of elements that
are more connected to each other than to the other elements in the network. We
introduce MODULAR to perform rapid and autonomous calculation of modularity in
sets of networks. MODULAR reads a set of files with matrices or edge lists that
represent unipartite or bipartite networks, and identify modules using two
different modularity metrics that have been previously used in studies of
ecological networks. To find the network partition that maximizes modularity,
the software offers five optimization methods to the user. We also included two
of the most common null models that are used in studies of ecological networks
to verify how the modularity found by the maximization of each metric differs
from a theoretical benchmark.


title: Wolff's Theorem on Ideals for Matrices

abstract:
  We extend Wolff's theorem concerning ideals on H-infinity(D) to the matrix
case, giving conditions under which an H-infinity solution G to the equation FG
= H exists for all z in D, where F is an m-by-infinity matrix of functions in
H-infinity (D), and H is an m-by-1 vector of such functions. We then examine
several useful results.


title: An octave bandwidth frequency independent dipole antenna

abstract:
  Precision measurements of the spectrum of the cosmic radio background require
frequency independent antennas of small electrical dimensions. We describe the
design of a wide-band fat-dipole antenna with a sinusoidal profile having a
frequency independent performance over the octave band 87.5 to 175 MHz. The
input return loss exceeds 15 dB and the radiation power pattern is frequency
invariant and close to cosine square over the octave bandwidth. The structure
has been optimized using electromagnetic modeling, and the design has been
validated by constructing a prototype.


title: On the key exchange with nonlinear polynomial maps of stable degree

abstract:
  We say that the sequence $g_n$, $n\ge 3$, $n \rightarrow \infty$ of
polynomial transformation bijective maps of free module $K^n$ over commutative
ring $K$ is a sequence of stable degree if the order of $g_n$ is growing with
$n$ and the degree of each nonidentical polynomial map of kind ${g_n}^k$ is an
independent constant $c$. A transformation $b={\tau}
  {g_n}^k {\tau}^{-1}$, where $\tau$ is affine bijection, $n$ is large and $k$
is relatively small, can be used as a base of group theoretical Diffie-Hellman
key exchange algorithm for the Cremona group $C(K^n)$ of all regular
automorphisms of $K^n$. The specific feature of this method is that the order
of the base may be unknown for the adversary because of the complexity of its
computation. The exchange can be implemented by tools of Computer Algebra
(symbolic computations). The adversary can not use the degree of righthandside
in $b^x=d$ to evaluate unknown $x$ in this form for the discrete logarithm
problem.
  In the paper we introduce the explicit constructions of sequences of elements
of stable degree for cases $c=3$ for each commutative ring $K$ containing at
least 3 regular elements and discuss the implementation of related key exchange
and public key algorithms.


title:
Negative Thermal Expansion in cubic ZrW2O8: Role of Phonons in Entire
  Brillouin Zone From ab-inito Calculations

abstract:
  We report ab-inito density functional theory calculation of phonons in cubic
phase of ZrW2O8 in the entire Brillouin zone and identify specific anharmonic
phonons that are responsible for large negative thermal expansion (NTE) in
terms of translation, rotation and distortion of WO4 and ZrO6. We have used
density functional calculations to interpret the experimental phonon spectra as
a function of pressure and temperature as reported in literature. We discover
that the phonons showing anharmonicty with temperature are different from those
showing anharmonicity with pressure although both are of similar frequencies.
Only the latter phonons are associated with NTE. Therefore the cubic and/or
quadratic anharmonicity of phonons is not relevant to NTE but just the volume
dependence of frequencies. The calculations are able to reproduce the observed
anomalous trends, namely, the softening of the low frequency peak at about 5
meV in the phonon spectra with pressure and its hardening with temperature,
while both the changes involve a compression of the lattice.


title:
Universal threshold for the dynamical behavior of lattice systems with
  long-range interactions

abstract:
  Dynamical properties of lattice systems with long-range pair interactions,
decaying like 1/r^{\alpha} with the distance r, are investigated, in particular
the time scales governing the relaxation to equilibrium. Upon varying the
interaction range \alpha, we find evidence for the existence of a threshold at
\alpha=d/2, dependent on the spatial dimension d, at which the relaxation
behavior changes qualitatively and the corresponding scaling exponents switch
to a different regime. Based on analytical as well as numerical observations in
systems of vastly differing nature, ranging from quantum to classical, from
ferromagnetic to antiferromagnetic, and including a variety of lattice
structures, we conjecture this threshold and some of its characteristic
properties to be universal.