title: Computational complexity of time-dependent density functional theory

abstract:
  Time-dependent density functional theory (TDDFT) is rapidly emerging as a
premier method for solving dynamical many-body problems in physics and
chemistry. The mathematical foundations of TDDFT are established through the
formal existence of a fictitious non-interacting system (known as the Kohn-Sham
system), which can reproduce the one-electron reduced probability density of
the actual system. We build upon these works and show that on the interior of
the domain of existence, the Kohn-Sham system can be efficiently obtained given
the time-dependent density. Since a quantum computer can efficiently produce
such time-dependent densities, we present a polynomial time quantum algorithm
to generate the time-dependent Kohn-Sham potential with controllable error
bounds. As a consequence, in contrast to the known intractability result for
ground state density functional theory (DFT), the computation of the necessary
time-dependent potentials given the initial state is in the complexity class
described by bounded error quantum computation in polynomial time (BQP).


title:
Alternativity of stable distributions in linear topological spaces, with
  criterion

abstract:
  We give in this short report a very simple proof of Zero-One Law for the
stable distributions in Linear Topological Spaces (LTS).


title:
An asymptotically tight bound on the Q-index of graphs with forbidden
  cycles

abstract:
  Let G be a graph of order n and let q(G) be that largest eigenvalue of the
signless Laplacian of G. In this note it is shown that if k>1 and q(G)>=n+2k-2,
then G contains cycles of length l whenever 2<l<2k+3. This bound is
asymptotically tight. It implies an asymptotic solution to a recent conjecture
about the maximum q(G) of a graph G with no cycle of a specified length.


title: Mixed-lag synchronization in coupled counter-rotating oscillators

abstract:
  We report mixed lag synchronization in coupled counter-rotating oscillators.
The trajectories of counter-rotating oscillators has opposite directions of
rotation in uncoupled state. Under diffusive coupling via a scalar variable, a
mixed lag synchronization emerges when a parameter mismatch is induced in two
counter-rotating oscillators. In the state of mixed lag synchronization, one
pair of state variables achieve synchronization shifted in time while another
pair of state variables are in antisynchronization, however, they are too
shifted by the same time. Numerical example of the paradigmatic R{\"o}ssler
oscillator is presented and supported by electronic experiment.


title: ${}_{\Lambda\Lambda}^{4}$H in halo effective field theory

abstract:
  The ${}_{\Lambda\Lambda}^{\ \ 4}$H bound state and the $S$-wave
hypertriton(${}_\Lambda^{ \, 3}$H)-$\Lambda$ scattering in spin singlet and
triplet channels below the hypertriton breakup momentum scale are studied in
halo/cluster effective field theory at leading order by treating the
${}_{\Lambda\Lambda}^{\ \ 4}$H system as a three-cluster
($\Lambda$-$\Lambda$-deuteron) system. In the spin singlet channel, the
amplitude is insensitive to the cutoff parameter $\Lambda_c$ introduced in the
integral equation, and we find that there is no bound state. In this case, the
scattering length of the hypertriton-$\Lambda$ scattering is found to be
$a_0^{} = 16.0\pm 3.0$ fm. In the spin triplet channel, however, the amplitude
obtained by the coupled integral equations is sensitive to $\Lambda_c$, and we
introduce the three-body contact interaction $g_1^{} (\Lambda_c)$. After
phenomenologically fixing $g_1^{} (\Lambda_c)$, we find that the correlation
between the two-$\Lambda$ separation energy $B_{\Lambda\Lambda}$ from the
$_{\Lambda\Lambda}^{\ \ 4}$H bound state and the scattering length
$a_{\Lambda\Lambda}^{}$ of the $S$-wave $\Lambda$-$\Lambda$ scattering is
significantly sensitive to the value of $\Lambda_c$.


title:
The nematic phase in stripe forming systems within the self consistent
  screening approximation

abstract:
  We show that in order to describe the isotropic-nematic transition in stripe
forming systems with isotropic competing interactions of the Brazovskii class
it is necessary to consider the next to leading order in a 1/N approximation
for the effective Hamiltonian. This can be conveniently accomplished within the
self-consistent screening approximation. We solve the relevant equations and
show that the self-energy in this approximation is able to generate the
essential wave vector dependence to account for the anisotropic character of
two-point correlation function characteristic of a nematic phase.


title:
AIR: fused Analytical and Iterative Reconstruction method for computed
  tomography

abstract:
  Purpose: CT image reconstruction techniques have two major categories:
analytical reconstruction (AR) method and iterative reconstruction (IR) method.
AR reconstructs images through analytical formulas, such as filtered
backprojection (FBP) in 2D and Feldkamp-Davis-Kress (FDK) method in 3D, which
can be either mathematically exact or approximate. On the other hand, IR is
often based on the discrete forward model of X-ray transform and formulated as
a minimization problem with some appropriate image regularization method, so
that the reconstructed image corresponds to the minimizer of the optimization
problem. This work is to investigate the fused analytical and iterative
reconstruction (AIR) method.
  Methods: Based on IR with L1-type image regularization, AIR is formulated
with a AR-specific preconditioner in the data fidelity term, which results in
the minimal change of the solution algorithm that replaces the adjoint X-ray
transform by the filtered X-ray transform. As a proof-of-concept 2D example of
AIR, FBP is incorporated into tensor framelet (TF) regularization based IR, and
the formulated AIR minimization problem is then solved through split Bregman
method with GPU-accelerated X-ray transform and filtered adjoint X-ray
transform.
  Conclusion: AIR, the fused Analytical and Iterative Reconstruction method, is
proposed with a proof-of-concept 2D example to synergize FBP and TF-regularized
IR, with improved image resolution and contrast for experimental data. The
potential impact of AIR is that it offers a general framework to develop
various AR enhanced IR methods, when neither AR nor IR alone is sufficient.


title: Orthogonal-state-based protocols of quantum key agreement

abstract:
  Two orthogonal-state-based protocols of quantum key agreement (QKA) are
proposed. The first protocol of QKA proposed here is designed for two-party
QKA, whereas the second protocol is designed for multi-party QKA. Security of
these orthogonal-state-based protocols arise from monogamy of entanglement.
This is in contrast to the existing protocols of QKA where security arises from
the use of non-orthogonal state (non-commutativity principle). Further, it is
shown that all the quantum systems that are useful for implementation of
quantum dialogue and most of the protocols of secure direct quantum
communication can be modified to implement protocols of QKA.


title: How learn the branching ratio X(3872)\to D^{*0}\bar D^0 + c.c

abstract:
  Enfant terrible of charmonium spectroscopy, the resonance $X(3872)$,
generated a stream of interpretations and ushered in a new exotic $XYZ$
spectroscopy. In th meantime, many (if not all) characteristics of $X(3872)$
are rather ambiguous. We construct spectra of decays of the resonance $X(3872)$
with good analytical and unitary properties which allows to define the
branching ratio of the $X(3872) \to D^{*0}\bar D^0 + c.c.$ decay studying only
one more decay, for example, the $X(3872)\to\pi^+\pi^- J/\psi(1S)$ decay. We
next define the range of values of the coupling constant of the $X(3872)$
resonance with the $D^{*0}\bar D^0$ system. Finally, we show that our spectra
are effective means of selection of models for the resonance $X(3872)$.


title:
Proposal: A Search for Sterile Neutrino at J-PARC Materials and Life
  Science Experimental Facility

abstract:
  We propose a definite search for sterile neutrinos at the J-PARC Materials
and Life Science Experimental Facility (MLF). With the 3 GeV Rapid Cycling
Synchrotron (RCS) and spallation neutron target, an intense neutrino beam from
muon decay at rest (DAR) is available. Neutrinos come from \mu+ decay, and the
oscillation to be searched for is (anti \nu \mu -> anti \nu e) which is
detected by the inverse \beta decay interaction (anti \nu e + p -> e+ + n),
followed by a gamma from neutron capture.
  The unique features of the proposed experiment, compared with the LSND and
experiments using horn focused beams, are;
  (1) The pulsed beam with about 600 ns spill width from J-PARC RCS and muon
long lifetime allow us to select neutrinos from \mu DAR only.
  (2) Due to nuclear absorption of \pi- and \mu-, neutrinos from \mu- decay are
suppressed to about the $10^{-3}$ level.
  (3) Neutrino cross sections are well known. The inverse \beta decay cross
section is known to be a few percent accuracy.
  (4) The neutrino energy can be calculated from positron energy by adding ~1.8
MeV.
  (5) The anti \nu \mu and \nu e fluxes have different and well defined
spectra. This allows us to separate oscillated signals from those due to \mu-
decay contamination.
  We propose to proceed with the oscillation search in steps since the region
of \Delta m^2 to be searched can be anywhere between sub-eV^2 to several tens
of eV^2. We start to examine the large \Delta m^2 region, which can be done
with short baseline at first. At close distance to the MLF target gives a high
neutrino flux, and allows us to use relatively small detector.
  If no definitive positive signal is found, a future option exists to cover
small \Delta m^2 region. This needs a relatively long baseline and requires a
large detector to compensate for the reduced neutrino flux.


title: Hot Spine Loops and the Nature of a Late-Phase Solar Flare

abstract:
  The fan-spine magnetic topology is believed to be responsible for many
curious features in solar explosive events. A spine field line links distinct
flux domains, but direct observation of such feature has been rare. Here we
report a unique event observed by the Solar Dynamic Observatory where a set of
hot coronal loops (over 10 MK) connected to a quasi-circular chromospheric
ribbon at one end and a remote brightening at the other. Magnetic field
extrapolation suggests these loops are partly tracer of the evolving spine
field line. Continuous slipping- and null-point-type reconnections were likely
at work, energizing the loop plasma and transferring magnetic flux within and
across the fan quasi-separatrix layer. We argue that the initial reconnection
is of the "breakout" type, which then transitioned to a more violent flare
reconnection with an eruption from the fan dome. Significant magnetic field
changes are expected and indeed ensued. This event also features an
extreme-ultraviolet (EUV) late phase, i.e. a delayed secondary emission peak in
warm EUV lines (about 2-7 MK). We show that this peak comes from the cooling of
large post-reconnection loops beside and above the compact fan, a direct
product of eruption in such topological settings. The long cooling time of the
large arcades contributes to the long delay; additional heating may also be
required. Our result demonstrates the critical nature of cross-scale magnetic
coupling - topological change in a sub-system may lead to explosions on a much
larger scale.


title: Squaring-Up Method In the Presence of Transmission Zeros

abstract:
  This paper presents a method to square up a generic MIMO system that already
possesses transmission zeros. The proposed method is developed based on and
therefore can be incorporated into the existing method that has been proven
effective on a system without transmission zeros. It has been shown that for
the generic system considering here, the squaring-up problem can be transformed
into a state-feedback problem with uncontrollable modes.


title: Approximate String Matching using a Bidirectional Index

abstract:
  We study strategies of approximate pattern matching that exploit
bidirectional text indexes, extending and generalizing ideas of Lam et al. We
introduce a formalism, called search schemes, to specify search strategies of
this type, then develop a probabilistic measure for the efficiency of a search
scheme, prove several combinatorial results on efficient search schemes, and
finally, provide experimental computations supporting the superiority of our
strategies.


title: Mechano-freezing of the ambient water

abstract:
  Raman spectroscopy examination of the 25 deg-C water freezing under
compression revealed transition from 1.35 GPa to 0.86 GPa upon ice being formed
at continued volume change. The transition is associated with a slight blue
shift of the high-frequency phonon (omiga_H ~ 3120 cm-1) and creation of the
low-frequency phonons (Omiga_L ~ 200 cm-1). In the liquid and in the solid
phase, the increased pressure softens the Omiga_H and stiffens the Omida_L,
which indicates the presence of the inter-electron-pair repulsion in both
liquid and solid water.


title: Binary Cyclic Codes from Explicit Polynomials over $\gf(2^m)$

abstract:
  Cyclic codes are a subclass of linear codes and have applications in consumer
electronics, data storage systems, and communication systems as they have
efficient encoding and decoding algorithms. In this paper, monomials and
trinomials over finite fields with even characteristic are employed to
construct a number of families of binary cyclic codes. Lower bounds on the
minimum weight of some families of the cyclic codes are developed. The minimum
weights of other families of the codes constructed in this paper are
determined. The dimensions of the codes are flexible. Some of the codes
presented in this paper are optimal or almost optimal in the sense that they
meet some bounds on linear codes. Open problems regarding binary cyclic codes
from monomials and trinomials are also presented.


title:
Finite size scaling in crossover among different random matrix ensembles
  in microscopic lattice models

abstract:
  Using numerical diagonalization we study the crossover among different random
matrix ensembles [Poissonian, Gaussian Orthogonal Ensemble (GOE), Gaussian
Unitary Ensemble (GUE) and Gaussian Symplectic Ensemble (GSE)] realized in two
different microscopic models. The specific diagnostic tool used to study the
crossovers is the level spacing distribution. The first model is a one
dimensional lattice model of interacting hard core bosons (or equivalently spin
1/2 objects) and the other a higher dimensional model of non-interacting
particles with disorder and spin orbit coupling. We find that the perturbation
causing the crossover among the different ensembles scales to zero with system
size as a power law with an exponent that depends on the ensembles between
which the crossover takes place. This exponent is independent of microscopic
details of the perturbation. We also find that the crossover from the
Poissonian ensemble to the other three is dominated by the Poissonian to GOE
crossover which introduces level repulsion while the crossover from GOE to GUE
or GOE to GSE associated with symmetry breaking introduces a subdominant
contribution. We also conjecture that the exponent is dependent on whether the
system contains interactions among the elementary degrees of freedom or not and
is independent of the dimensionality of the system.


title: Can Google Trends search queries contribute to risk diversification?

abstract:
  Portfolio diversification and active risk management are essential parts of
financial analysis which became even more crucial (and questioned) during and
after the years of the Global Financial Crisis. We propose a novel approach to
portfolio diversification using the information of searched items on Google
Trends. The diversification is based on an idea that popularity of a stock
measured by search queries is correlated with the stock riskiness. We penalize
the popular stocks by assigning them lower portfolio weights and we bring
forward the less popular, or peripheral, stocks to decrease the total riskiness
of the portfolio. Our results indicate that such strategy dominates both the
benchmark index and the uniformly weighted portfolio both in-sample and
out-of-sample.


title:
Design of a 325MHz Beta=0.12 superconducting single spoke cavity for
  China-ADS

abstract:
  Twelve superconducting single spoke cavities whose Beta is 0.12 (Spoke012)
operating at 325MHz, are adopted in Injector I for China-ADS linac. This type
of spoke cavity is believed to be one of the key challenges for its very low
geometry Beta. So far, the prototype cavity has been designed, fabricated and
tested successfully. The design work was finished by using CST-MWS and ANSYS
software for the RF and mechanical properties optimization. This paper presents
the details of the final design for Spoke012 prototype cavity.


title:
Fractal Markets Hypothesis and the Global Financial Crisis: Wavelet
  Power Evidence

abstract:
  We analyze whether the prediction of the fractal markets hypothesis about a
dominance of specific investment horizons during turbulent times holds. To do
so, we utilize the continuous wavelet transform analysis and obtained wavelet
power spectra which give the crucial information about the variance
distribution across scales and its evolution in time. We show that the most
turbulent times of the Global Financial Crisis can be very well characterized
by the dominance of short investment horizons which is in hand with the
assertions of the fractal markets hypothesis.


title:
Singlet portal extensions of the standard seesaw models to dark sector
  with local dark symmetry: An alternative to the new minimal standard model

abstract:
  Assuming dark matter is absolutely stable due to unbroken dark gauge symmetry
and singlet operators are portals to the dark sector, we present a simple
extension of the standard seesaw model that can accommodate all the
cosmological observations as well as terrestrial experiments available as of
now, including leptogenesis, extra dark radiation of $\sim 0.08$ (resulting in
$N_{\rm eff} = 3.130$ the effective number of neutrino species), Higgs
inflation, small and large scale structure formation, and current relic density
of scalar DM ($X$). The Higgs signal strength is equal to one as in the SM for
unbroken $U(1)_X$ case with a scalar dark matter, but it could be less than one
independent of decay channels if the dark matter is a dark sector fermion or if
$U(1)_X$ is spontaneously broken, because of a mixing with a new neutral scalar
boson in the models.


title:
Space Efficient Linear Time Lempel-Ziv Factorization on
  Constant~Size~Alphabets

abstract:
  We present a new algorithm for computing the Lempel-Ziv Factorization (LZ77)
of a given string of length $N$ in linear time, that utilizes only $N\log N +
O(1)$ bits of working space, i.e., a single integer array, for constant size
integer alphabets. This greatly improves the previous best space requirement
for linear time LZ77 factorization (K\"arkk\"ainen et al. CPM 2013), which
requires two integer arrays of length $N$. Computational experiments show that
despite the added complexity of the algorithm, the speed of the algorithm is
only around twice as slow as previous fastest linear time algorithms.


title: Non-linear Redundancy Calibration

abstract:
  For radio interferometric arrays with a sufficient number of redundant
spacings the multiplicity of measurements of the same sky visibility can be
used to determine both the antenna gains as well as the true visibilities. Many
of the earlier approaches to this problem focused on linearized versions of the
relation between the measured and the true visibilities. Here we propose to use
a standard non-linear minimization algorithm to solve for both the antenna
gains as well as the true visibilities. We show through simulations done in the
context of the ongoing upgrade to the Ooty Radio Telescope that the non-linear
minimization algorithm is fast compared to the earlier approaches. Further,
unlike the most straightforward linearized approach, which works with the
logarithms of the visibilities and the gains, the non-linear minimization
algorithm leads to unbiased solutions. Finally we present error estimates for
the estimated gains and visibilities. Monte-Carlo simulations establish that
the estimator is indeed statistically efficient, achieving the Cramer-Rao
bound.


title: Statistical Mechanics of DNA Rupture: Theory and Simulations

abstract:
  We study the effects of the shear force on the rupture mechanism on a double
stranded DNA. Motivated by recent experiments, we perform the atomistic
simulations with explicit solvent to obtain the distributions of extension in
hydrogen and covalent bonds below the rupture force. We obtain a significant
difference between the atomistic simulations and the existing results in the
iterature based on the coarse-grained models (theory and simulations). We
discuss the possible reasons and improve the coarse-grained model by
incorporating the consequences of semi-microscopic details of the nucleotides
in its description. The distributions obtained by the modified model
(simulations and theoretical) are qualitatively similar to the one obtained
using atomistic simulations.


title:
NV-Center Based Digital Quantum Simulation of a Quantum Phase Transition
  in Topological Insulators

abstract:
  Nitrogen-vacancy centers in diamond are ideal platforms for quantum
simulation, which allows one to handle problems that are intractable
theoretically or experimentally. Here we propose a digital quantum simulation
scheme to simulate the quantum phase transition occurring in an ultrathin
topological insulator film placed in a parallel magnetic field [Zyuzin
\textit{et al.}, Phys. Rev. B \textbf{83}, 245428 (2011)]. The quantum
simulator employs high quality spin qubits achievable in nitrogen-vacancy
centers and can be realized with existing technology. The problem can be mapped
onto the Hamiltonian of two entangled qubits represented by the electron and
nuclear spins. The simulation uses the Trotter algorithm, with an operation
time of the order of 100 $\mu$s for each individual run.


title: Weyl-invariant extension of the Metric-Affine Gravity

abstract:
  Metric-affine geometry provides a non-trivial extension of the general
relativity where the metric and connection are treated as the two independent
fundamental quantities in constructing the space-time (with non-vanishing
torsion and non-metricity). In this paper we study the generic form of action
in this formalism, and then construct the Weyl-invariant version of this
theory. It is shown that in Weitzenbock space, the obtained Weyl-invariant
action can cover the conformally invariant teleparallel action. Finally the
related field equations are obtained in the general case.


title:
Enantiomer-specific isotope analysis of D- and L-alanine: Nitrogen
  isotopic hetero- and homogeneity in microbial and chemical processes

abstract:
  Nitrogen isotopic hetero- and homogeneity of D-{\alpha}-alanine and
L-{\alpha}-alanine were investigated in microbial processes in the domain
Bacteria and in chemical processes in symmetric organic synthesis. D-alanine is
an enantiomer that is physiologically essential for microbial growth and
metabolic maintenance. The nitrogen isotopic difference {\Delta}15ND-L (defined
as {\delta}15ND-Ala - {\delta}15NL-Ala) in peptidoglycan amino acids in
bacteria such as the representative gram-positive phyla Firmicutes and
Actinobacteria (Enterococcus faecalis, Staphylococcus aureus, Staphylococcus
staphylolyticus, Lactobacillus acidophilus, Bacillus subtilis, Micrococcus
luteus, and Streptomyces sp.) tended to be 15N-depleted in D-alanine
({\Delta}15ND-L < -2.0 permil). These results suggest that the composition of
isotopically heterogeneous components in these bacteria is primarily controlled
by enzymatic pathways prior to formation of the bacterial cell wall. In
contrast, the {\Delta}15ND-L of racemic alanine in the chemical pathway during
the nucleophilic substitution reaction (SN1 type) between 2-bromopropionic acid
and ammonia identified fully homogeneous components for each enantiomer. The
novel enantiomer-specific isotopic analysis (ESIA) method is useful in
determining the origins of chirality in biogenic and abiogenic processes and is
applicable to enantiomer studies.
  -- Keywords: D-alanine, microbial process, chemical process, nitrogen
isotopic composition, enantiomer-specific isotope analysis (ESIA)


title: Transverse target spin asymmetries in exclusive $\rho^0$ muoproduction

abstract:
  Exclusive production of $\rho^0$ mesons was studied at the COMPASS experiment
by scattering 160 GeV/$c$ muons off transversely polarised protons. Five
single-spin and three double-spin azimuthal asymmetries were measured as a
function of $Q^2$, $x_{Bj}$, or $p_{T}^{2}$. The $\sin \phi_S$ asymmetry is
found to be $-0.019 \pm 0.008(stat.) \pm 0.003(syst.)$. All other asymmetries
are also found to be of small magnitude and consistent with zero within
experimental uncertainties. Very recent calculations using a GPD-based model
agree well with the present results. The data is interpreted as evidence for
the existence of chiral-odd, transverse generalized parton distributions.


title:
A critical assessment on Kassapoglou's statistical model for composites
  fatigue

abstract:
  Kassapoglou recently proposed a model for fatigue of composite materials
which seems to suggest that fatigue SN curve can be entirely predicted on the
basis of the statistical distribution of static strengths. The original
abstract writes "Expressions for the cycles to failure as a function of R ratio
are derived. These expressions do not require any curve fitting and do not
involve any experimentally determined parameters. The fatigue predictions do
not require any fatigue tests for calibration". These surprisingly ambitious
claims and attractive results deserve careful scrutiny. We contend that the
results seem to be due to a number of approximations and incorrect derivations,
and one particular misleading assumption, which make the model not conform to a
fatigue testing in a given specimen with resulting SN curve distribution. The
quantitative agreement of some predictions (the scatter of distribution of
fatigue lives being close to the mode value found in typical composites of
aeronautical interest in the large Navy database) should not motivate any
enthusiasm. It is believed that a proper statistical treatment of the fatigue
process should not make wear-out constants disappear, and hence the SN curves
would depend on them, and not just on scatter of static data. These serious
concerns explain the large discrepancies found by 3 independent studies which
tried to apply Kassapoglou's model to composite fatigue data, and to other well
known results.


title:
Intermediate-energy electron-impact dissociative ionization-excitation
  of molecular hydrogen

abstract:
  We have implemented three variants of the exterior complex scaling procedure
in prolate spheroidal coordinates (PS-ECS) to study the dissociative electron
impact ionization-excitation of hydrogen molecule, where the emerging electrons
and one of the protons are detected in coincidence for the first time in a
recent experiment. In the first variant, designated PSECS-1B, the two target
electrons are treated ab initio while the interaction of the incident-scattered
electron is taken into account using the first term of the Born series. In the
second, PSECS-2BCD, the second Born term is introduced in the dipole
approximation. In the third approach, designated PSECS-SW, applied to the
ionization-excitation to the $2p\sigma_u$ level of H$_2^+$, the
multi-configurational single active electron approximation is used for the
target, while the interaction of the incident electron with the target is
described ab initio. Our results agree partially with those of a recent
experiment which is in progress.


title:
Ferrimagnetism in the Heisenberg-Ising Bilayer with Magnetically
  Non-equivalent Planes

abstract:
  The Pair Approximation method is applied to the antiferromagnetic
Heisenberg-Ising spin-1/2 bilayer with a simple cubic crystalline structure.
The method allows for self-consistent calculations of thermodynamic quantities,
based on the determination of Gibbs free-energy. In the paper the phase
diagrams and planar magnetizations are calculated for the system in question.
Special attention is paid to the case of magnetically non-equivalent planes,
one of which is additionally randomly diluted. The occurrence of a compensation
phenomenon is found and the compensation temperature is discussed for such a
system. The characteristic concentration of magnetic atoms $p^{\star}$, below
which the compensation phenomenon vanishes, is examined as a function of the
Hamiltonian parameters.


title: Freely Falling Observer and Black Hole Radiation

abstract:
  We find radiation in an infalling frame and present an explicit analytic
evidence of the failure of no drama condition by showing that an infalling
observer finds an infinite negative energy density at the event horizon. The
negative and positive energy density regions are divided by the newly defined
zero-energy curve. The evaporating black hole is surrounded by the negative
energy which can also be observed in the infalling frame.


title: Rayleigh-Taylor Instability at Ionization Fronts: Perturbation Analysis

abstract:
  The linear growth rate of the Rayleigh-Taylor instability (RTI) at ionization
fronts is investigated via perturbation analysis in the limit of incompressible
fluids. In agreement with previous numerical studies is found that absorption
of ionizing radiation inside the HII region due to hydrogen recombinations
suppresses the growth of instabilities. In the limit of a large density
contrast at the ionization front the RTI growth rate has the simple analytical
solution n=-nur+(nur^2+gk)^(1/2), where nur is the hydrogen recombination rate
inside the HII region, k is the perturbation's wavenumber and g is the
effective acceleration in the frame of reference of the front. Therefore, the
growth of surface perturbations with wavelengths lambda >> lambda_{cr} = 2\pi
g/nur^2 is suppressed by a factor (lambda_{cr}/4lambda)^(1/2) with respect to
the non-radiative incompressible RTI. Implications on stellar and black hole
feedback are briefly discussed.


title: Cosmology and Stability in Scalar-Tensor bigravity

abstract:
  The bigravity models coupled with two scalar fields are constructed. We show
that a wide class of the expansion history of the universe, especially
corresponding to dark energy and/or inflation, can be described by a solution
of the bigravity model. We discuss the stability of the solution and give the
conditions for the stability. We also explicitly construct a model which gives
a stable solution. By using the stable model, for an arbitrary evolution of the
universe expansion, we construct the Brans-Dicke like model which reproduces
the evolution.


title: Magnetization in electron- and Mn- doped SrTiO3

abstract:
  Mn-doped SrTiO_3.0, when synthesized free of impurities, is a paramagnetic
insulator with interesting dielectric properties. Since delocalized charge
carriers are known to promote ferromagnetism in a large number of systems via
diverse mechanisms, we have looked for the possibility of any intrinsic,
spontaneous magnetization by simultaneous doping of Mn ions and electrons into
SrTiO_3 via oxygen vacancies, thereby forming SrTi_(1-x)Mn_xO_(3-d), to the
extent of making the doped system metallic. We find an absence of any
enhancement of the magnetization in the metallic sample when compared with a
similarly prepared Mn doped, however, insulating sample. Our results, thus, are
not in agreement with a recent observation of a weak ferromagnetism in metallic
Mn doped SrTiO_3 system.


title:
Statistical Inference of a canonical dictionary of protein substructural
  fragments

abstract:
  Proteins are biomolecules of life. They fold into a great variety of
three-dimensional (3D) shapes. Underlying these folding patterns are many
recurrent structural fragments or building blocks (analogous to `LEGO bricks').
This paper reports an innovative statistical inference approach to discover a
comprehensive dictionary of protein structural building blocks from a large
corpus of experimentally determined protein structures. Our approach is built
on the Bayesian and information-theoretic criterion of minimum message length.
To the best of our knowledge, this work is the first systematic and rigorous
treatment of a very important data mining problem that arises in the
cross-disciplinary area of structural bioinformatics. The quality of the
dictionary we find is demonstrated by its explanatory power -- any protein
within the corpus of known 3D structures can be dissected into successive
regions assigned to fragments from this dictionary. This induces a novel
one-dimensional representation of three-dimensional protein folding patterns,
suitable for application of the rich repertoire of character-string processing
algorithms, for rapid identification of folding patterns of newly-determined
structures. This paper presents the details of the methodology used to infer
the dictionary of building blocks, and is supported by illustrative examples to
demonstrate its effectiveness and utility.


title: Gate-defined coupled quantum dots in topological insulators

abstract:
  We consider electrostatically coupled quantum dots in topological insulators,
otherwise confined and gapped by a magnetic texture. By numerically solving the
(2+1) Dirac equation for the wave packet dynamics, we extract the energy
spectrum of the coupled dots as a function of bias-controlled coupling and an
external perpendicular magnetic field. We show that the tunneling energy can be
controlled to a large extent by the electrostatic barrier potential.
Particularly interesting is the coupling via Klein tunneling through a resonant
valence state of the barrier. The effective three-level system nicely maps to a
model Hamiltonian, from which we extract the Klein coupling between the
confined conduction and valence dots levels. For large enough magnetic fields
Klein tunneling can be completely blocked due to the enhanced localization of
the degenerate Landau levels formed in the quantum dots.


title:
Local mechanical properties of electrospun fibers correlate to their
  internal nanostructure

abstract:
  The properties of polymeric nanofibers can be tailored and enhanced by
properly managing the structure of the polymeric molecules at the nanoscale.
Although electrospun polymer fibers are increasingly exploited in many
technological applications, their internal nanostructure, determining their
improved physical properties, is still poorly investigated and understood.
Here, we unravel the internal structure of electrospun functional nanofibers
made by prototype conjugated polymers. The unique features of near field
optical measurements are exploited to investigate the nanoscale spatial
variation of the polymer density, evidencing the presence of a dense internal
core embedded in a less dense polymeric shell. Interestingly, nanoscale mapping
the fiber Young's modulus demonstrates that the dense core is stiffer than the
polymeric, less dense shell. These findings are rationalized by developing a
theoretical modeling and simulations of the polymer molecular structural
evolution during the electrospinning process. This model predicts that the
stretching of the polymer network induces a contraction towards the jet center
of the network with a local increase of the polymer density, as observed in the
solid structure. The found complex internal structure opens interesting
perspective for improving and tailoring the molecular morphology and
multifunctional electronic and optical properties of polymer fibers.


title:
Observation of environment-induced double sudden transitions in
  geometric quantum correlations

abstract:
  Correlations in quantum systems exhibit a rich phenomenology under the effect
of various sources of noise. We investigate theoretically and experimentally
the dynamics of quantum correlations and their classical counterparts in two
nuclear magnetic resonance setups, as measured by geometric quantifiers based
on trace-norm. We consider two-qubit systems prepared in Bell diagonal states,
and perform the experiments in decohering environments resulting from Bell
diagonal-preserving Markovian local noise. We then report the first observation
of environment-induced double sudden transitions in the geometric quantum
correlations, a genuinely nonclassical effect not observable in classical
correlations. The evolution of classical correlations in our physical
implementation reveals in turn the finite-time relaxation to a pointer basis
under nondissipative decoherence, which we characterize geometrically in full
analogy with predictions based on entropic measures.


title:
Effect of "dipolar-biasing" on the tunability of tunneling
  magnetoresistance in transition metal oxide systems

abstract:
  We observe an unusual tunneling magnetoresistance (TMR) phenomenon in a
composite of La$_{2/3}$Sr$_{1/3}$MnO$_{3}$ with CoFe$_{2}$O$_{4}$ where the TMR
versus applied magnetic field loop suggests a "negative coercive field".
Tracing its origin back to a "dipolar-biasing" of La$_{2/3}$Sr$_{1/3}$MnO$_{3}$
by CoFe$_{2}$O$_{4}$, we show that the TMR of even a single composite can be
tuned continuously so that the resistance peak or the highest sensitivity of
the TMR can be positioned anywhere on the magnetic field axis with a suitable
magnetic history of the sample. This phenomenon of an unprecedented tunability
of the TMR should be present in general in all such composites.


title: Comment on "Possible divergences in Tsallis' thermostatistics"

abstract:
  The problematic divergence of the $q$-partition function of the harmonic
oscillator recently considered in \cite{plastino} is a particular case of the
non-normalizabilty of the distribution function of classical Hamiltonian
systems in non-extensive thermostatistics as discussed previously in
\cite{lutsko-boon}.


title:
Threshold effects and renormalization group evolution of neutrino
  parameters in TeV scale seesaw models

abstract:
  We consider the threshold effect on the renormalization group (RG) evolution
of the neutrino masses and mixing angles in TeV scale seesaw models. We obtain
the analytic expressions using the factorization method in presence of
threshold effects. We also perform numerical study of RG effects in two
specific low scale seesaw models following the bottom-up approach and ascertain
the role of seesaw thresholds in altering the values of masses and mixing
angles during RG evolution.


title:
Engineered spin-valve type magnetoresistance in
  Fe$_3$O$_4$-CoFe$_2$O$_4$ core-shell nanoparticles

abstract:
  Naturally occurring spin-valve-type magnetoresistance (SVMR), recently
observed in Sr2FeMoO6 samples, suggests the possibility of decoupling the
maximal resistance from the coercivity of the sample. Here we present the
evidence that SVMR can be engineered in specifically designed and fabricated
core-shell nanoparticle systems, realized here in terms of soft magnetic Fe3O4
as the core and hard magnetic insulator CoFe2O4 as the shell materials. We show
that this provides a magnetically switchable tunnel barrier that controls the
magnetoresistance of the system, instead of the magnetic properties of the
magnetic grain material, Fe3O4, and thus establishing the feasibility of
engineered SVMR structures.


title: Submicrosecond-timescale readout of carbon nanotube mechanical motion

abstract:
  We report fast readout of the motion of a carbon nanotube mechanical
resonator. A close-proximity high electron mobility transistor amplifier is
used to increase the bandwidth of the measurement of nanotube displacements
from the kHz to the MHz regime. Using an electrical detection scheme with the
nanotube acting as a mixer, we detect the amplitude of its mechanical motion at
room temperature with an intermediate frequency of 6 MHz and a timeconstant of
780 ns, both up to five orders of magnitude faster than achieved before. The
transient response of the mechanical motion indicates a ring-down time faster
than our enhanced time resolution, placing an upper bound on the contribution
of energy relaxation processes to the room temperature mechanical quality
factor.


title: Coulomb gap refrigerator

abstract:
  We propose a remarkably simple electronic refrigerator based on the Coulomb
barrier for single-electron tunneling. A fully normal single-electron
transistor is voltage $V$ biased at a gate position such that tunneling through
one of the junctions costs an energy of about $k_BT \ll eV, E_C$, where $T$ is
the temperature and $E_C$ is the transistor charging energy. The tunneling in
the junction with positive energy cost cools both the electrodes attached to
it. Immediate practical realizations of such a refrigerator make use of Andreev
mirrors which suppress heat current while maintaining full electric contact.


title: Transversity in exclusive vector-meson leptoproduction

abstract:
  The role of transversity or helicity-flip generalized parton distributions
(GPDs) in leptoproduction of vector mesons is investigated within the framework
of the handbag approach. The transversity GPDs in combination with twist-3
meson wave functions, occur in the amplitudes for transitions from a
transversely polarized virtual photon to a longitudinal polarized vector meson.
The importance of the transversity GPDs can be examined in some of the spin
density matrix elements and in transverse target spin asymmetries. Using
suitable parametrizations of both helicity-flip and non-flip GPDs, which are
essentially taken from our previous papers, we estimate these observables and
compare the results with available data.


title: The fractal dimensions of the spectrum of Sturm Hamiltonian

abstract:
  Let $\alpha\in(0,1)$ be irrational and $[0;a_1,a_2,\cdots]$ be the continued
fraction expansion of $\alpha$. Let $H_{\alpha,V}$ be the Sturm Hamiltonian
with frequency $\alpha$ and coupling $V$, $\Sigma_{\alpha,V}$ be the spectrum
of $H_{\alpha,V}$. The fractal dimensions of the spectrum have been determined
by Fan, Liu and Wen (Erg. Th. Dyn. Sys.,2011) when $\{a_n\}_{n\ge1}$ is
bounded. The present paper will treat the most difficult case, i.e,
$\{a_n\}_{n\ge1}$ is unbounded. We prove that for $V\ge24$, $$ \dim_H\
\Sigma_{\alpha,V}=s_*(V)\ \ \ \text{and}\ \ \ \bar{\dim}_B\
\Sigma_{\alpha,V}=s^*(V), $$ where $s_*(V)$ and $s^*(V)$ are lower and upper
pre-dimensions respectively. By this result, we determine the fractal
dimensions of the spectrums for all Sturm Hamiltonians.
  We also show the following results: $s_*(V)$ and $s^*(V)$ are Lipschitz
continuous on any bounded interval of $[24,\infty)$; the limits $s_*(V)\ln V$
and $s^*(V)\ln V$ exist as $V$ tend to infinity, and the limits are constants
only depending on $\alpha$; $s^\ast(V)=1$ if and only if
$\limsup_{n\to\infty}(a_1\cdots a_n)^{1/n}=\infty,$ which can be compared with
the fact: $s_\ast(V)=1$ if and only if $\liminf_{n\to\infty}(a_1\cdots
a_n)^{1/n}=\infty$(Liu and Wen, Potential anal. 2004).


title: Stochastic superparameterization in quasigeostrophic turbulence

abstract:
  In this article we expand and develop the authors' recent proposed
methodology for efficient stochastic superparameterization (SP) algorithms for
geophysical turbulence. Geophysical turbulence is characterized by significant
intermittent cascades of energy from the unresolved to the resolved scales
resulting in complex patterns of waves, jets, and vortices. Conventional SP
simulates large scale dynamics on a coarse grid in a physical domain, and
couples these dynamics to high-resolution simulations on periodic domains
embedded in the coarse grid. Stochastic SP replaces the nonlinear,
deterministic eddy equations on periodic embedded domains by quasilinear
stochastic approximations on formally infinite embedded domains. The result is
a seamless algorithm which never uses a small scale grid and is far cheaper
than conventional SP, but with significant success in difficult test problems.
Various design choices in the algorithm are investigated in detail here,
including decoupling the timescale of evolution on the embedded domains from
the length of the time step used on the coarse grid, and sensitivity to certain
assumed properties of the eddies (e.g. the shape of the assumed eddy energy
spectrum). The different design choices are compared and contrasted on a
stringent test suite for quasigeostrophic turbulence involving two-layer
dynamics on a beta-plane forced by an imposed background shear. The algorithms
developed are expected to be particularly useful in providing accurate and
efficient stochastic parameterizations for use in ensemble-based state
estimation and prediction.


title:
An Axiom System for General Relativity Complete with respect to
  Lorentzian Manifolds

abstract:
  We introduce several axiom systems for general relativity and show that they
are complete with respect to the standard models of general relativity, i.e.,
to Lorentzian manifolds having the corresponding smoothness properties.


title:
The nature of the ISM in galaxies during the star-formation activity
  peak of the Universe

abstract:
  We combine a semi-analytic model of galaxy formation, tracking atomic and
molecular phases of cold gas, with a three-dimensional radiative-transfer and
line tracing code to study the sub-mm emission from atomic and molecular
species (CO, HCN, [CI], [CII], [OI]) in galaxies. We compare the physics that
drives the formation of stars at the epoch of peak star formation (SF) in the
Universe (z = 2.0) with that in local galaxies. We find that normal
star-forming galaxies at high redshift have much higher CO-excitation peaks
than their local counterparts and that CO cooling takes place at higher
excitation levels. CO line ratios increase with redshift as a function of
galaxy star-formation rate, but are well correlated with H2 surface density
independent of redshift. We find an increase in the [OI]/[CII] line ratio in
typical star-forming galaxies at z = 1.2 and z = 2.0 with respect to
counterparts at z = 0. Our model results suggest that typical star-forming
galaxies at high redshift consist of much denser and warmer star-forming clouds
than their local counterparts. Galaxies belonging to the tail of the SF
activity peak at z = 1.2 are already less dense and cooler than counterparts
during the actual peak of SF activity (z = 2.0). We use our results to discuss
how future ALMA surveys can best confront our predictions and constrain models
of galaxy formation.


title: Temporal and spacial evolution of bursts in creep rupture

abstract:
  We investigate the temporal and spacial evolution of single bursts and their
statistics emerging in heterogeneous materials under a constant external load.
Based on a fiber bundle model we demonstrate that when the load redistribution
is localized along a propagating crack front, the average temporal shape of
pulses has a right handed asymmetry, however, for long range interaction a
symmetric shape with parabolic functional form is obtained. The pulse shape and
spatial evolution of bursts proved to be correlated which can be exploited in
materials' testing. The probability distribution of the size and duration of
bursts have power law behavior with a crossover to higher exponents as the load
is lowered. The crossover emerges due to the competition of the slow and fast
modes of local breaking being dominant at low and high loads, respectively.


title:
Brittle to Ductile Transition in a Fiber Bundle with Strong
  Heterogeneity

abstract:
  We analyze the failure process of a two-component system with widely
different fracture strength in the framework of a fiber bundle model with
localized load sharing. A fraction 0\leq \alpha \leq 1 of the bundle is strong
and it is represented by unbreakable fibers, while fibers of the weak component
have randomly distributed failure strength. Computer simulations revealed that
there exists a critical composition \alpha_c which separates two qualitatively
different behaviors: below the critical point the failure of the bundle is
brittle characterized by an abrupt damage growth within the breakable part of
the system. Above \alpha_c, however, the macroscopic response becomes ductile
providing stability during the entire breaking process. The transition occurs
at an astonishingly low fraction of strong fibers which can have importance for
applications. We show that in the ductile phase the size distribution of
breaking bursts has a power law functional form with an exponent \mu=2 followed
by an exponential cutoff. In the brittle phase the power law also prevails but
with a higher exponent \mu=9/2. The transition between the two phases shows
analogies to continuous phase transitions. Analyzing the microstructure of the
damage, it was found that at the beginning of the fracture process cracks
nucleate randomly, while later on growth and coalescence of cracks dominate
which give rise to power law distributed crack sizes.


title:
Wide band Fresnel super-resolution applied to capillary break up of
  viscoelastic fluids

abstract:
  We report a technique based on Fresnel diffraction with white illumination
that permits the resolution of capillary surface patterns of less than 100
nanometers. We investigate Rayleigh Plateaux like instability on a viscoelastic
capillary bridge and show that we can overcome the resolution limit of optical
microscopy. The viscoelastic filaments are approximately 20 microns thick at
the end of the thinning process when the instability sets in. The wavy
distortions grow exponentially in time and the pattern is resolved by an image
treatment that is based on an approximation of the measured rising flank of the
first Fresnel peak.


title: On doubly warped product immersions

abstract:
  In this paper we study fundamental geometric properties of doubly warped
product immersion which is an extension of warped product immersion. Moreover,
we study geometric inequality for doubly warped products isometrically immersed
in arbitrary Riemannian manifolds.


title: Strongly correlated superconductivity

abstract:
  Band theory and BCS theory are arguably the most successful theories of
condensed matter physics. Yet, in a number of materials, in particular the
high-temperature superconductors and the layered organic superconductors, they
fail. In these lecture notes for an international school, I emphasize that even
though the low energy properties of a phase of matter are generally emergent
and entirely determined by the broken symmetry, there are many differences
between a strongly correlated and a weakly correlated state of matter. For
example, spin waves are an emergent property for antiferromagnets, but for weak
correlations the normal phase of a (Slater) antiferromagnet is metallic,
whereas it is insulating (Heisenberg) for strong correlations. As a function of
interaction strength, above the antiferromagnetic phase, the crossover between
a metal and a local moment paramagnetic insulator is described by the Mott
transition, whose mean-field theory down to T=0 is best formulated with
dynamical mean-field theory. A similar situation occurs for superconductors:
despite similar emergent properties, there are many differences between both
kinds of superconductors. Experimental evidence suggests that hole-doped
cuprates are strongly correlated whereas the correlations are weaker in the
electron-doped case, especially near optimal doping. Evidence for a pseudogap
arising from antiferromagnetic fluctuations is strong in the latter case,
whereas in the hole-doped case the pseudogap temperature appears as a
consequence of Mott physics. In cluster dynamical mean-field theory, the
pseudogap line T* is a Widom line arising from a T=0 first-order transition
that terminates at a finite T critical point. Strongly correlated
superconductors are much more resilient to near-neighbor repulsion than their
weakly correlated counterpart. Many different methods to attack these problems
theoretically are described.


title:
Effective viscosity of non-gravitactic Chlamydomonas Reinhardtii
  microswimmer suspensions

abstract:
  Active microswimmers are known to affect the macroscopic viscosity of
suspensions in a more complex manner than passive particles. For puller-like
microswimmers an increase in the viscosity has been observed. It has been
suggested that the persistence of the orientation of the microswimmers hinders
the rotation that is normally caused by the vorticity. It was previously shown
that some sorts of algaes are bottom-heavy swimmers, i.e. their centre of mass
is not located in the centre of the body. In this way, the algae affects the
vorticity of the flow when it is perpendicular oriented to the axis of gravity.
This orientation of gravity to vorticity is given in a rheometer that is
equipped with a cone-plate geometry. Here we present measurements of the
viscosity both in a cone-plate and a Taylor-Couette cell. The two set-ups
yielded the same increase in viscosity although the axis of gravitation in the
Taylor-Couette cell is parallel to the direction of vorticity. In a
complementary experiment we tested the orientation of the direction of swimming
through microscopic observation of single \textit{Chlamydomonas reinhardtii}
and could not identify a preferred orientation, i. e. our specific strain of
\textit{Chlamydomonas reinhardtii} are not bottom-heavy swimmers. We thus
conclude that bottom heaviness is not a prerequisite for the increase of
viscosity and that the effect of gravity on the rheology of our strain of
\textit{Chlamydomonas reinhardtii} is negligible. This finding reopens the
question of whether origin of persistence in the orientation of cells is
actually responsible for the increased viscosity of the suspension.


title: Aggregation of Red Blood Cells: From Rouleaux to Clot Formation

abstract:
  Red blood cells are known to form aggregates in the form of rouleaux. This
aggregation process is believed to be reversible, but there is still no full
understanding on the binding mechanism. There are at least two competing
models, based either on bridging or on depletion. We review recent experimental
results on the single cell level and theoretical analyses of the depletion
model and of the influence of the cell shape on the binding strength. Another
important aggregation mechanism is caused by activation of platelets. This
leads to clot formation which is life saving in the case of wound healing but
also a major cause of death in the case of a thrombus induced stroke. We review
historical and recent results on the participation of red blood cells in clot
formation.


title: Quantum Probability Theory and the Foundations of Quantum Mechanics

abstract:
  We attempt to contribute some novel points of view to the "foundations of
quantum mechanics", using mathematical tools from "quantum probability theory"
(such as the theory of operator algebras). We first introduce an abstract
algebraic framework for the formulation of mathematical models of physical
systems that is general enough to encompass classical and quantum mechanical
models. After a short discussion on the properties of classical systems
(realism and determinism), we move on to the study of a general class of
quantum-mechanical models of physical systems and explain what some of the key
problems in a quantum theory of observations and measurements are. In the last
part of our essay, we attempt to elucidate the roles played by entanglement
between a system and its environment and of information loss in understanding
"decoherence" and "dephasing", which are key mechanisms in a quantum theory of
measurements and experiments. We also discuss the problem of "time in quantum
mechanics" and sketch an answer to the question when an experiment can be
considered to have been completed successfully.


title:
Porting Large HPC Applications to GPU Clusters: The Codes GENE and
  VERTEX

abstract:
  We have developed GPU versions for two major high-performance-computing (HPC)
applications originating from two different scientific domains. GENE is a
plasma microturbulence code which is employed for simulations of nuclear fusion
plasmas. VERTEX is a neutrino-radiation hydrodynamics code for "first
principles"-simulations of core-collapse supernova explosions. The codes are
considered state of the art in their respective scientific domains, both
concerning their scientific scope and functionality as well as the achievable
compute performance, in particular parallel scalability on all relevant HPC
platforms. GENE and VERTEX were ported by us to HPC cluster architectures with
two NVidia Kepler GPUs mounted in each node in addition to two Intel Xeon CPUs
of the Sandy Bridge family. On such platforms we achieve up to twofold gains in
the overall application performance in the sense of a reduction of the time to
solution for a given setup with respect to a pure CPU cluster. The paper
describes our basic porting strategies and benchmarking methodology, and
details the main algorithmic and technical challenges we faced on the new,
heterogeneous architecture.

categories: physics.comp-ph astro-ph.SR cs.DC physics.plasm-ph


title:
Two-node queueing network with a heavy-tailed random input: the strong
  stability case

abstract:
  We consider a two-node fluid network with batch arrivals of random size
having a heavy-tailed distribution. We are interested in the tail asymptotics
for the stationary distribution of a two-dimensional queue-length process. The
tail asymptotics have been well studied for two-dimensional reflecting
processes where jumps have either a bounded or an unbounded light-tailed
distribution. However, presence of heavy tails totally changes the asymptotics.
Here we focus on the case of strong stability where both nodes release fluid
with sufficiently high speeds to minimise their mutual influence. We show that,
like in the one-dimensional case, big jumps provide the main cause for queues
to become large, but now they may have multi-dimensional features. For deriving
these results, we develop an analytic approach that differs from the
traditional tail asymptotic studies, and obtain various weak tail equivalences.
Then, in the case of one-dimensional subexponential jump-size distributions, we
find the exact asymptotics based on the sample-path arguments.


title: On division of quasianalytic function germs

abstract:
  In this paper, we establish the following criterion for divisibility in the
local ring of those quasianalytic function germs at zero which are definable in
a polynomially bounded structure. A sufficient (and necessary) condition for
the divisibility of two such function germs is that of their Taylor series at
zero in the formal power series ring.


title:
Dynamic Team Theory of Stochastic Differential Decision Systems with
  Decentralized Noiseless Feedback Information Structures via Girsanov's
  Measure Transformation

abstract:
  In this paper we generalized static team theory to dynamic team theory, in
the context of stochastic differential decision system with decentralized
noiseless feedback information structures.
  We apply Girsanov's theorem to transformed the initial stochastic dynamic
team problem to an equivalent team problem, under a reference probability
space, with state process and information structures independent of any of the
team decisions. Subsequently, we show, under certain conditions, that
continuous-time and discrete-time stochastic dynamic team problems, can be
transformed to equivalent static team problems, although computing the optimal
team strategies using this method might be computational intensive. Therefore,
we propose an alternative method, by deriving team and Person-by-Person (PbP)
optimality conditions, via the stochastic Pontryagin's maximum principle,
consisting of forward and backward stochastic differential equations, and a set
of conditional variational Hamiltonians with respect to the information
structures of the team members.
  Finally, we relate the backward stochastic differential equation to the value
process of the stochastic team problem.


title: Why "noncommuting common causes" don't explain anything

abstract:
  In my commentary, I will argue that the conclusions drawn in the paper
"Noncommutative causality in algebraic quantum field" theory by G\'abor
Hofer-Szab\'o (and similar publications) are incorrect. As proven by J.S. Bell,
a local common causal explanation of correlations violating the Bell inequality
is impossible.


title: Eigenvalues of the Laplacian on a compact manifold with density

abstract:
  In this paper, we study the spectrum of the weighted Laplacian (also called
Bakry-Emery or Witten Laplacian) $L_\sigma$ on a compact, connected, smooth
Riemannian manifold $(M,g)$ endowed with a measure $\sigma dv_g$. First, we
obtain upper bounds for the $k-$th eigenvalue of $L_{\sigma}$ which are
consistent with the power of $k$ in Weyl's formula. These bounds depend on
integral norms of the density $\sigma$, and in the second part of the article,
we give examples showing that this dependence is, in some sense, sharp. As a
corollary, we get bounds for the eigenvalues of Laplace type operators, such as
the Schr\"{o}dinger operator or the Hodge Laplacian on $p-$forms. In the
special case of the weighted Laplacian on the sphere, we get a sharp inequality
for the first nonzero eigenvalue which extends Hersch's inequality.


title:
Phase transition and entropy spectrum of BTZ black hole in
  three-dimensional gravity with torsion

abstract:
  In this paper, we study the phase transition and the entropy spectrum of BTZ
black hole obtained in a model of three-dimensional gravity with torsion. By
calculating the heat capacity we find that the BTZ black hole we considered
will experience phase transition at some critical point. This indicates that
the critical behaviors of black holes do not only depend on the spacetime
metric, but have to do with the theory of gravity under consideration. In
addition we derived the entropy spectrum of the BTZ black hole according to the
quasinormal modes(QNMs) and the adiabatic invariance. It shows that the area or
entropy spectrum will also rely on the concrete gravitational action.


title:
Constructive geometrization of Thurston maps and decidability of
  Thurston equivalence

abstract:
  The key result in the present paper is a direct analogue of the celebrated
Thurston's Theorem for marked Thurston maps with parabolic orbifolds. Combining
this result with previously developed techniques, we prove that every Thurston
map can be constructively geometrized in a canonical fashion. As a consequence,
we give a partial resolution of the general problem of decidability of Thurston
equivalence of two postcritically finite branched covers of the two-sphere.


title: Gap Amplification for Small-Set Expansion via Random Walks

abstract:
  In this work, we achieve gap amplification for the Small-Set Expansion
problem. Specifically, we show that an instance of the Small-Set Expansion
Problem with completeness $\epsilon$ and soundness $\frac{1}{2}$ is at least as
difficult as Small-Set Expansion with completeness $\epsilon$ and soundness
$f(\epsilon)$, for any function $f(\epsilon)$ which grows faster than
$\sqrt{\epsilon}$. We achieve this amplification via random walks -- our gadget
is the graph with adjacency matrix corresponding to a random walk on the
original graph. An interesting feature of our reduction is that unlike gap
amplification via parallel repetition, the size of the instances (number of
vertices) produced by the reduction remains the same.


title: Liouville Theorem for 2D Navier-Stokes equations in Half Space

abstract:
  In the paper, a Liouville theorem for mild bounded ancient solutions to the
2D Navier-Stokes equations in half space has been proven.


title: Role of normalization in spectral clustering for stochastic blockmodels

abstract:
  Spectral clustering is a technique that clusters elements using the top few
eigenvectors of their (possibly normalized) similarity matrix. The quality of
spectral clustering is closely tied to the convergence properties of these
principal eigenvectors. This rate of convergence has been shown to be identical
for both the normalized and unnormalized variants in recent random matrix
theory literature. However, normalization for spectral clustering is commonly
believed to be beneficial [Stat. Comput. 17 (2007) 395-416]. Indeed, our
experiments show that normalization improves prediction accuracy. In this
paper, for the popular stochastic blockmodel, we theoretically show that
normalization shrinks the spread of points in a class by a constant fraction
under a broad parameter regime. As a byproduct of our work, we also obtain
sharp deviation bounds of empirical principal eigenvalues of graphs generated
from a stochastic blockmodel.


title: On the infimum attained by the reflected fractional Brownian motion

abstract:
  Let $\{B_H(t):t\ge 0\}$ be a fractional Brownian motion with Hurst parameter
$H\in(\frac{1}{2},1)$. For the storage process $Q_{B_H}(t)=\sup_{-\infty\le
s\le t} \left(B_H(t)-B_H(s)-c(t-s)\right)$ we show that, for any $T(u)>0$ such
that $T(u)=o(u^\frac{2H-1}{H})$, \[\mathbb P (\inf_{s\in[0,T(u)]}
Q_{B_H}(s)>u)\sim\mathbb P(Q_{B_H}(0)>u),\quad\text{as}\quad u\to\infty.\] This
finding, known in the literature as the strong Piterbarg property, is in line
with previously observed properties of storage processes with self-similar and
infinitely divisible input without Gaussian component.


title: Magnetospheric Accretions and the Inner Winds of Classical T Tauri Stars

abstract:
  Recent spectropolarimetric observations suggest that young low-mass stars
such as classical T Tauri stars (CTTSs) possess relatively strong (~kG)
magnetic field. This supports a scenario in which the final accretion onto the
stellar surface proceeds through a magnetosphere, and the winds are formed in
magnetohydrodynamics (MHD) processes. We examine recent numerical simulations
of magnetospheric accretions via an inclined dipole and a complex magnetic
fields. The difference between a stable accretion regime, in which accretion
occurs in ordered funnel streams, and an unstable regime, in which gas
penetrates through the magnetosphere in several unstable streams due to the
magnetic Rayleigh-Taylor instability, will be discussed. We describe how MHD
simulation results can be used in separate radiative transfer (RT) models to
predict observable quantiles such as line profiles and light curves. The
plausibility of the accretion flows and outflows predicted by MHD simulations
(via RT models) can be tested against observations. We also address the issue
of outflows/winds that arise from the innermost part of CTTSs. First, we
discuss the line formations in a simple disk wind and a stellar wind models. We
then discuss the formation of the conically shaped magnetically driven outflow
that arises from the disk-magnetosphere boundary when the magnetosphere is
compressed into an X-type configuration.


title:
Deeper Into the Folksonomy Graph: FolkRank Adaptations and Extensions
  for Improved Tag Recommendations

abstract:
  The information contained in social tagging systems is often modelled as a
graph of connections between users, items and tags. Recommendation algorithms
such as FolkRank, have the potential to leverage complex relationships in the
data, corresponding to multiple hops in the graph. We present an in-depth
analysis and evaluation of graph models for social tagging data and propose
novel adaptations and extensions of FolkRank to improve tag recommendations. We
highlight implicit assumptions made by the widely used folksonomy model, and
propose an alternative and more accurate graph-representation of the data. Our
extensions of FolkRank address the new item problem by incorporating content
data into the algorithm, and significantly improve prediction results on
unpruned datasets. Our adaptations address issues in the iterative weight
spreading calculation that potentially hinder FolkRank's ability to leverage
the deep graph as an information source. Moreover, we evaluate the benefit of
considering each deeper level of the graph, and present important insights
regarding the characteristics of social tagging data in general. Our results
suggest that the base assumption made by conventional weight propagation
methods, that closeness in the graph always implies a positive relationship,
does not hold for the social tagging domain.


title:
Rate of Convergence of Phase Field Equations in Strongly Heterogeneous
  Media towards their Homogenized Limit

abstract:
  We study phase field equations based on the diffuse-interface approximation
of general homogeneous free energy densities showing different local minima of
possible equilibrium configurations in perforated/porous domains. The study of
such free energies in homogeneous environments found a broad interest over the
last decades and hence is now widely accepted and applied in both science and
engineering. Here, we focus on strongly heterogeneous materials with
perforations such as porous media. To the best of our knowledge, we present a
general formal derivation of upscaled phase field equations for arbitrary free
energy densities and give a rigorous justification by error estimates for a
broad class of polynomial free energies. The error between the effective
macroscopic solution of the new upscaled formulation and the solution of the
microscopic phase field problem is of order $\epsilon^1/2$ for a material given
characteristic heterogeneity $\epsilon$. Our new, effective, and reliable
macroscopic porous media formulation of general phase field equations opens new
modelling directions and computational perspectives for interfacial transport
in strongly heterogeneous environments.


title: A theory of function-induced-orders to study recursion termination

abstract:
  Termination property of functions is an important issue in computability
theory. In this paper, we show that repeated iterations of a function can
induce an order amongst the elements of its domain set. Hasse diagram of the
poset, thus obtained, is shown to look like a forest of trees, with a possible
base set and a generator set (defined in the paper). Isomorphic forests may
arise for different functions and equivalences classes are, thus, formed. Based
on this analysis, a study of the class of deterministically terminating
functions is presented, in which the existence of a Self-Ranking Program, which
can prove its own termination, and a Universal Terminating Function, from which
every other terminating function can be derived, is conjectured.


title: Mantel's Theorem for Random Hypergraphs

abstract:
  A classical result in extremal graph theory is Mantel's Theorem, which states
that every maximum triangle-free subgraph of $K_n$ is bipartite. A sparse
version of Mantel's Theorem is that, for sufficiently large $p$, every maximum
triangle-free subgraph of $G(n,p)$ is w.h.p. bipartite. Recently, DeMarco and
Kahn proved this for $p > K \sqrt{\log n/n}$ for some constant $K$, and apart
from the value of the constant this bound is best possible. We study an
extremal problem of this type in random hypergraphs. Denote by $F_5$, which
sometimes called as the generalized triangle, the 3-uniform hypergraph with
vertex set {a,b,c,d,e} and edge set {abc, ade, bde}. One of the first extremal
results in extremal hypergraph theory is by Frankl and F\"{u}redi, who proved
that the maximum 3-uniform hypergraph on n vertices containing no copy of $F_5$
is tripartite for n>3000. A natural question is for what p is every maximum
$F_5$-free subhypergraph of $G^3(n,p)$ w.h.p. tripartite. We show this holds
for $p>K\log n/n$ for some constant K and does not hold for $p=0.1\sqrt{\log
n}/n$.


title:
Randomized Approximation of the Gram Matrix: Exact Computation and
  Probabilistic Bounds

abstract:
  Given a real matrix A with n columns, the problem is to approximate the Gram
product AA^T by c << n weighted outer products of columns of A. Necessary and
sufficient conditions for the exact computation of AA^T (in exact arithmetic)
from c >= rank(A) columns depend on the right singular vector matrix of A. For
a Monte-Carlo matrix multiplication algorithm by Drineas et al. that samples
outer products, we present probabilistic bounds for the 2-norm relative error
due to randomization. The bounds depend on the stable rank or the rank of A,
but not on the matrix dimensions. Numerical experiments illustrate that the
bounds are informative, even for stringent success probabilities and matrices
of small dimension. We also derive bounds for the smallest singular value and
the condition number of matrices obtained by sampling rows from orthonormal
matrices.


title:
Comment on "A self-assembled three-dimensional cloak in the visible" in
  Scientific Reports 3, 2328

abstract:
  M\"uhlig et. al. propose and fabricate a "cloak" comprised of nano-particles
on the surface of a sub-wavelength silica sphere. However, the coating only
reduces the scattered fields. This is achieved by increased absorption, such
that total extinction increases at all wavelengths. An object creating a large
shadow is generally not considered to be cloaked; functionally, in contrast to
the relatively few structures that can reduce total extinction, there are many
that can reduce scattering alone.


title:
Photon-induced thermal effects in superconducting coplanar waveguide
  resonators

abstract:
  We experimentally investigated the optical responses of a superconducting
niobium resonator. It was found that, with increasing radiation power, the
resonance frequency increases monotonically below around 500 mK, decreases
monotonically above around 1 K and exhibits a nonmonotonic behavior at around
700 mK. These observations show that one can operate the irradiated resonator
in three temperature regimes, depending on whether two-level system (TLS)
effects or kinetic inductance effects dominate. Furthermore, we found that the
optical responses at ultra-low temperatures can be qualitatively regarded as a
photon-induced thermalization effect of TLSs, which could be utilized to
achieve thermal sensitive photon detections.


title: Involutions, odd-degree extensions and generic splitting

abstract:
  Let $q$ be a quadratic form over a field $F$ and let $L$ be a field extension
of $F$ of odd degree. It is a classical result that if $q_L$ is isotropic
(resp. hyperbolic) then $q$ is isotropic (resp. hyperbolic). In turn, given two
quadratic forms $q, q^\prime$ over $F$, if $q_L \cong q^\prime_L$ then $q \cong
q^\prime$. It is natural to ask whether similar results hold for algebras with
involution. We give a survey of the progress on these three questions with
particular attention to the relevance of hyperbolicity, isotropy and
isomorphism over some {appropriate} function field. Incidentally, we prove the
anisotropy property in some {new} low degree cases.


title: Codeless Screen-Oriented Programming for Enterprise Mobile Applications

abstract:
  Designing the user interface (UI) of mobile applications in the enterprise is
performed in many cases by the application users who represent the business
needs. This is based on existing developed enterprise services that can be
accessed by these applications. Design the UI of the mobile applications
require programming environments that are as much as possible codeless and easy
to use. In this paper, we present NitroGen which is a cloud-based
platform-independent tool that provides with no installation, a consumable
integrated set of capabilities to construct mobile solutions aiming at reducing
development and maintenance costs. We further illustrate how to use NitroGen
showing its visual touch-based mostly codeless way of programming. NitroGen can
easily connect to back-end services thus enable fast and facile development in
enterprises.


title:
Newton representation of functions over natural integers having integral
  difference ratios

abstract:
  Different questions lead to the same class of functions from natural integers
to integers: those which have integral difference ratios, i.e. verifying
$f(a)-f(b)\equiv0 \pmod {(a-b)}$ for all $a>b$.
  We characterize this class of functions via their representations as Newton
series. This class, which obviously contains all polynomials with integral
coefficients, also contains unexpected functions, for instance all functions
$x\mapsto\lfloor e^{1/a}\;a^x\;x!\rfloor$, with $a\in\Z\setminus\{0,1\}$, and a
function equal to $\lfloor e\;x!\rfloor$ except on 0. Finally, to study the
complement class, we look at functions $\N\to\RR$ which are not uniformly close
to any function having integral difference ratios.


title:
A Chiellini type integrability condition for the generalized first kind
  Abel differential equation

abstract:
  The Chiellini integrability condition of the first order first kind Abel
equation $dy/dx=f(x)y^2+g(x)y^3$ is extended to the case of the general Abel
equation of the form $dy/dx=a(x)+b(x)y+f(x)y^{\alpha -1}+g(x)y^{\alpha}$, where
$\alpha \in \Re$, and $\alpha > 1$. In the case $\alpha =2$ the generalized
Abel equations reduces to a Riccati type equation, for which a Chiellini type
integrability condition is obtained.


title: Universal Pad\'{e} approximants and their behaviour on the boundary

abstract:
  There are several kinds of universal Taylor series. In one such kind the
universal approximation is required at every boundary point of the domain of
definition $\OO$ of the universal function $f$. In another kind the universal
approximation is not required at any point of $\partial\OO$ but in this case
the universal function $f$ can be taken smooth on $\oO$ and, moreover, it can
be approximated by it's Taylor partial sums on every compact subset of $\oO$.
Similar generic phenomena hold when the partial sums of the Taylor expansion of
the universal function are replaced by some Pad\'{e} approximants of it.
  In the present paper we show that in the case of Pad\'{e} approximants, if
$\OO$ is an open set and $S,T$ are two subsets of $\partial\OO$ that satisfy
some conditions, then there exists a universal function $f\in H(\OO)$ which is
smooth on $\OO\cup S$ and has some Pad\'{e} approximants that approximate $f$
on each compact subset of $\OO\cup S$ and simultaneously obtain universal
approximation on each compact subset of $(\C\sm\oO)\cup T$. A sufficient
condition for the above to happen is $\oS\cap\oT=\emptyset$, while a necessary
and sufficient condition is not known.


title:
Massive MU-MIMO Downlink TDD Systems with Linear Precoding and Downlink
  Pilots

abstract:
  We consider a massive MU-MIMO downlink time-division duplex system where a
base station (BS) equipped with many antennas serves several single-antenna
users in the same time-frequency resource. We assume that the BS uses linear
precoding for the transmission. To reliably decode the signals transmitted from
the BS, each user should have an estimate of its channel. In this work, we
consider an efficient channel estimation scheme to acquire CSI at each user,
called beamforming training scheme. With the beamforming training scheme, the
BS precodes the pilot sequences and forwards to all users. Then, based on the
received pilots, each user uses minimum mean-square error channel estimation to
estimate the effective channel gains. The channel estimation overhead of this
scheme does not depend on the number of BS antennas, and is only proportional
to the number of users. We then derive a lower bound on the capacity for
maximum-ratio transmission and zero-forcing precoding techniques which enables
us to evaluate the spectral efficiency taking into account the spectral
efficiency loss associated with the transmission of the downlink pilots.
Comparing with previous work where each user uses only the statistical channel
properties to decode the transmitted signals, we see that the proposed
beamforming training scheme is preferable for moderate and low-mobility
environments.


title: Ion neutralisation mass-spectrometry route to radium monofluoride (RaF)

abstract:
  The diatomic molecule radium monofluoride (RaF) has recently been proposed as
a versatile probe for physics beyond the current standard model. Herein, a
route towards production of a RaF molecular beam via radium ions is proposed.
It takes advantage of the special electronic structure expected for group 2
halides and group 2 hydrides: The electronic ground state of neutral RaF and
its monocation differ in occupation of a non-bonding orbital of $\sigma$
symmetry. This implies similar equilibrium distances and harmonic vibrational
wavenumbers in the two charge states and thus favourable Franck--Condon factors
for neutralisation without dissociation in neutralising collisions. According
to the calculated ionisation energy of RaF, charge exchange collisions of
RaF$^+$ with sodium atoms are almost iso-enthalpic, resulting in large
cross-sections for the production of neutral radium monofluoride.


title: Bounds on inference

abstract:
  Lower bounds for the average probability of error of estimating a hidden
variable X given an observation of a correlated random variable Y, and Fano's
inequality in particular, play a central role in information theory. In this
paper, we present a lower bound for the average estimation error based on the
marginal distribution of X and the principal inertias of the joint distribution
matrix of X and Y. Furthermore, we discuss an information measure based on the
sum of the largest principal inertias, called k-correlation, which generalizes
maximal correlation. We show that k-correlation satisfies the Data Processing
Inequality and is convex in the conditional distribution of Y given X. Finally,
we investigate how to answer a fundamental question in inference and privacy:
given an observation Y, can we estimate a function f(X) of the hidden random
variable X with an average error below a certain threshold? We provide a
general method for answering this question using an approach based on
rate-distortion theory.


title: Gravitational self-force from radiation-gauge metric perturbations

abstract:
  Calculations of the gravitational self-force (GSF) in curved spacetime
require as input the metric perturbation in a sufficiently regular gauge. A
basic challenge in the program to compute the GSF for orbits around a Kerr
black hole is that the standard procedure for reconstructing the perturbation
is formulated in a class of radiation gauges, in which the particle singularity
is non-isotropic and extends away from the particle's location. Here we present
two practical schemes for calculating the GSF using a radiation-gauge
reconstructed metric as input. The schemes are based on a detailed analysis of
the local structure of the particle singularity in the radiation gauges. We
identify 3 types of radiation gauges: two containing a radial string-like
singularity emanating from the particle, either in one direction ("half-string"
gauges) or both directions ("full-string" gauges); and a third type containing
no strings but with a jump discontinuity across a surface intersecting the
particle. Based on a flat-space example, we argue that the standard
mode-by-mode reconstruction procedure yields the "regular half" of a
half-string solution, or (equivalently) either of the regular halves of a
no-string solution. For the half-string case, we formulate the GSF in a locally
deformed radiation gauge that removes the string singularity near the particle.
We derive a mode-sum formula for the GSF in this gauge, analogous to the
standard Lorenz-gauge formula but with modified regularization parameters. For
the no-string case, we formulate the GSF directly, without a local deformation,
and we derive a mode-sum formula that requires no correction to the parameters
but involves a certain averaging procedure. We explain the consistency of our
results with Gralla's invariance theorem, and discuss the correspondence
between our method and a related approach by Friedman et al.


title:
H\"older continuity of normal cycles and of support measures of convex
  bodies

abstract:
  We provide an estimate of the distance (in the dual flat seminorm) of the
normal cycles of convex bodies with given Hausdorff distance. We also give an
estimate (in the bounded Lipschitz metric) of the support measures of convex
bodies.


title:
Fluctuation-induced dynamics of multiphase liquid jets with ultra-low
  interfacial tension

abstract:
  Control of fluid dynamics at the micrometer scale is essential to emulsion
science and materials design, which is ubiquitous in everyday life and is
frequently encountered in industrial applications. Most studies on multiphase
flow focus on oil-water systems with substantial interfacial tension. Advances
in microfluidics have enabled the study of multiphase flow with more complex
dynamics. Here, we show that the evolution of the interface in a jet surrounded
by a co-flowing continuous phase with an ultra-low interfacial tension presents
new opportunities to the control of flow morphologies. The introduction of a
harmonic perturbation to the dispersed phase leads to the formation of
interfaces with unique shapes. The periodic structures can be tuned by
controlling the fluid flow rates and the input perturbation; this demonstrates
the importance of the inertial effects in flow control at ultra-low interfacial
tension. Our work provides new insights into microfluidic flows at ultra-low
interfacial tension and their potential applications.


title: Beating the jetting regime

abstract:
  We study numerically the dynamics of jets and drops in a microcapillary
co-flow device. The co-flow stream encounters different flow regimes, including
dripping, jetting. Using a level-set/finite element axysimmetric numerical
simulation, we study the dynamics of breakup of a jet subject to flow rate
perturbations. A scaling law for the width of the unperturbed jet is presented
and compared to existing experimental results as well as numerical
measurements. Then, we show that the introduction of a sinusoidal perturbation
of the inner fluid flow rate can facilitate breakup of the fluid in regimes
where a jet is usually observed. Moreover, the flow rate perturbation leads to
a good control over the size and the frequency of the resulting droplets. Using
theoretical modelling, we provide a criterion to determine the optimal
frequency to break up the jet. We also derive scaling laws to determine the
volume of inner fluid encapsulated in the emulsion droplets as a function of
the frequency and to estimate the distance for the jet to break up as a
function of the amplitude of perturbation. These scaling laws are in good
agreement with results of numerical simulations. Our work suggests a novel
approach and offers guiding principles to break up liquid jets in cases where
dripping is difficult to achieve.


title:
A couple of recent developments in the structure of the outer disk of
  the Milky Way

abstract:
  In this contribution we summarize recent achievements by our group on the
understanding of the structure of the outer Galactic disk, with particular
emphasis to the outer disk extent, and the spiral structure beyond the solar
circle.


title:
Contraction Principle based Robust Iterative Algorithms for Machine
  Learning

abstract:
  Iterative algorithms are ubiquitous in the field of data mining. Widely known
examples of such algorithms are the least mean square algorithm,
backpropagation algorithm of neural networks. Our contribution in this paper is
an improvement upon this iterative algorithms in terms of their respective
performance metrics and robustness. This improvement is achieved by a new
scaling factor which is multiplied to the error term. Our analysis shows that
in essence, we are minimizing the corresponding LASSO cost function, which is
the reason of its increased robustness. We also give closed form expressions
for the number of iterations for convergence and the MSE floor of the original
cost function for a minimum targeted value of the L1 norm. As a concluding
theme based on the stochastic subgradient algorithm, we give a comparison
between the well known Dantzig selector and our algorithm based on contraction
principle. By these simulations we attempt to show the optimality of our
approach for any widely used parent iterative optimization problem.


title:
Moments and Root-Mean-Square Error of the Bayesian MMSE Estimator of
  Classification Error in the Gaussian Model

abstract:
  The most important aspect of any classifier is its error rate, because this
quantifies its predictive capacity. Thus, the accuracy of error estimation is
critical. Error estimation is problematic in small-sample classifier design
because the error must be estimated using the same data from which the
classifier has been designed. Use of prior knowledge, in the form of a prior
distribution on an uncertainty class of feature-label distributions to which
the true, but unknown, feature-distribution belongs, can facilitate accurate
error estimation (in the mean-square sense) in circumstances where accurate
completely model-free error estimation is impossible. This paper provides
analytic asymptotically exact finite-sample approximations for various
performance metrics of the resulting Bayesian Minimum Mean-Square-Error (MMSE)
error estimator in the case of linear discriminant analysis (LDA) in the
multivariate Gaussian model. These performance metrics include the first,
second, and cross moments of the Bayesian MMSE error estimator with the true
error of LDA, and therefore, the Root-Mean-Square (RMS) error of the estimator.
We lay down the theoretical groundwork for Kolmogorov double-asymptotics in a
Bayesian setting, which enables us to derive asymptotic expressions of the
desired performance metrics. From these we produce analytic finite-sample
approximations and demonstrate their accuracy via numerical examples. Various
examples illustrate the behavior of these approximations and their use in
determining the necessary sample size to achieve a desired RMS. The
Supplementary Material contains derivations for some equations and added
figures.


title: Number of cycles in the graph of 312-avoiding permutations

abstract:
  The graph of overlapping permutations is defined in a way analogous to the De
Bruijn graph on strings of symbols. That is, for every permutation $\pi =
\pi_{1} \pi_{2} ... \pi_{n+1}$ there is a directed edge from the
standardization of $\pi_{1} \pi_{2} ... \pi_{n}$ to the standardization of
$\pi_{2} \pi_{3} ... \pi_{n+1}$. We give a formula for the number of cycles of
length $d$ in the subgraph of overlapping 312-avoiding permutations. Using this
we also give a refinement of the enumeration of 312-avoiding affine
permutations and point out some open problems on this graph, which so far has
been little studied.


title: Multiple collisions in turbulent flows

abstract:
  In turbulent suspensions, collision rates determine how rapidly particles
coalesce or react with each other. To determine the collision rate, many
numerical studies rely on the 'Ghost Collision Approximation' (GCA), which
simply records how often pairs of point particles come within a threshold
distance. In many applications, the suspended particles stick (or in the case
of liquid droplets, coalesce) upon collision, and it is the frequency of first
contact which is of interest. If a pair of 'ghost' particles undergoes multiple
collisions, the GCA may overestimate the true collision rate. Here, using fully
resolved Direct Numerical Simulations of turbulent flows at moderate Reynolds
number (R_\lambda = 130), we investigate the prevalence and properties of
multiple collisions. We demonstrate that the GCA leads to a systematic
overestimate of the collision rate, which is of the order of 15% when the
particle inertia is small, and slowly decreases when inertia increases. We
investigate the probability P(N) for a given pair of ghost particles colliding
N times. We find P(N)=\beta \alpha^N for N_>1, where \alpha and \beta are
coefficients which depend upon the particle inertia. This result is used to
explain the discrepancy between the GCA and the true collision rates. We also
investigate the statistics of the times that ghost particles remain in contact.
We show that the probability density function of the contact time is different
for the first collision. The difference is explained by the effect of caustics
in the phase space of the suspended particles.


title:
Unified Model of Temperature Dependence of Core Losses in Soft Magnetic
  Materials Exposed to Nonsinusoidal Flux Waveforms and DC Bias Condition

abstract:
  Assuming that Soft Magnetic Material is a Complex System and expressing this
feature by scaling invariance of the power loss characteristic, the unified
model of the temperature dependence of Core Losses in Soft Magnetic Materials
Exposed to Nonsinusoidal Flux Waveforms and DC Bias Condition has been
constructed.
  In order to verify this achievement the appropriate measurement data
concerning power losses and the all independent variables have been collected.
The model parameters have been estimated and the power losses modeling has been
performed. Comparison of the experimental values of power losses with their
calculated values has showed good agreement.


title: Symmetries and conserved quantities in Lindblad master equations

abstract:
  This work is concerned with determination of the steady-state structure of
time-independent Lindblad master equations, especially those possessing more
than one steady state. The approach here is to treat Lindblad systems as
generalizations of unitary quantum mechanics, extending the intuition of
symmetries and conserved quantities to the dissipative case. We combine and
apply various results to obtain an exhaustive characterization of the
infinite-time behavior of Lindblad evolution, including both the structure of
the infinite-time density matrix and its dependence on initial conditions. The
effect of the environment in the infinite time limit can therefore be tracked
exactly for arbitrary state initialization and without knowledge of dynamics at
intermediate time. As a consequence, sufficient criteria for determining the
steady state of a Lindblad master equation are obtained. These criteria are
knowledge of the initial state, a basis for the steady-state subspace, and all
conserved quantities. We give examples of two-qubit dissipation and single-mode
$d$-photon absorption where all quantities are determined analytically.
Applications of these techniques to quantum information, computation, and
feedback control are discussed.


title: On Background Independence

abstract:
  This paper concerns what Background Independence itself is (as opposed to
some particular physical theory that is background independent). The notions
presented mostly arose from a layer-by-layer analysis of the facets of the
Problem of Time in Quantum Gravity. Part of this coincides with two relational
postulates which are thus identified as classical precursors of two of the
facets of the Problem of Time. These are furthemore tied to the forms of each
of the GR Hamiltonian and momentum constraints. Other aspects of Background
Independence include the algebraic closure of these constraints, expressing
physics in terms of beables, foliation independence as implemented by
refoliation invariance, the reconstruction of spacetime from space. The final
picture is that Background Independence - a philosophically desirable and
physically implementable feature for a theory to have - has the facets of the
Problem of Time among its consequences. Thus these arise naturally and are
problems to be resolved, as opposed to avoided `by making one's physics
background-dependent in order not to have these problems'. This serves as a
selection criterion that limits the use of a number of model arenas and
physical theories.


title: Microscopic Evolution of Social Networks by Triad Position Profile

abstract:
  Disentangling the mechanisms underlying the social network evolution is one
of social science's unsolved puzzles. Preferential attachment is a powerful
mechanism explaining social network dynamics, yet not able to explain all
scaling-laws in social networks. Recent advances in understanding social
network dynamics demonstrate that several scaling-laws in social networks
follow as natural consequences of triadic closure. Macroscopic comparisons
between them are discussed empirically in many works. However the network
evolution drives not only the emergence of macroscopic scaling but also the
microscopic behaviors. Here we exploit two fundamental aspects of the network
microscopic evolution: the individual influence evolution and the process of
link formation. First we develop a novel framework for the microscopic
evolution, where the mechanisms of preferential attachment and triadic closure
are well balanced. Then on four real-world datasets we apply our approach for
two microscopic problems: node's prominence prediction and link prediction,
where our method yields significant predictive improvement over baseline
solutions. Finally to be rigorous and comprehensive, we further observe that
our framework has a stronger generalization capacity across different kinds of
social networks for two microscopic prediction problems. We unveil the
significant factors with a greater degree of precision than has heretofore been
possible, and shed new light on networks evolution.


title: Two hypergeometric tales and a new irrationality measure of $\zeta(2)$

abstract:
  We prove the new upper bound 5.095412 for the irrationality exponent of
$\zeta(2)=\pi^2/6$; the earlier record bound 5.441243 was established in 1996
by G. Rhin and C. Viola.


title:
Normal and Outlying Populations of the Milky Way Stellar Halo at [Fe/H]
  < -2

abstract:
  From detailed abundance analysis of >100 Hamburg/ESO candidate extremely
metal-poor (EMP) stars we find 45 with [Fe/H] < -3.0 dex. We identify a
heretofore unidentified group: Ca-deficient stars, with sub-solar [Ca/Fe]
ratios and the lowest neutron-capture abundances; the Ca-deficient group
comprises ~ 10% of the sample, excluding Carbon stars. Our radial velocity
distribution shows that the carbon-enhanced stars with no s-process
enhancements, CEMP-no, and which do not show C2 bands are not preferentially
binary systems. Ignoring Carbon stars, approximately 15% of our sample are
strong (> 5 sigma) outliers in one, or more, elements between Mg and Ni; this
rises to ~19% if very strong (>10 sigma) outliers for Sr and Ba are included.
Examples include: HE0305-0554 with the lowest [Ba/H] known; HE1012-1540 and
HE2323-0256, two (non-velocity variable) C-rich stars with very strong
[Mg,Al/Fe] enhancements; and HE1226-1149 an extremely r-process rich star.