title:
Multi-pomeron exchange model for $pp$ and $p\bar{p}$ collisions at
  ultra-high energy

abstract:
  A new variant of the effective pomeron exchange model is proposed for the
description of the correlation, observed in $pp$ and $p\bar{p}$ collisions at
center-of-mass energy from SPS to LHC, between mean transverse momentum and
charged particles multiplicity. The model is based on the Regge-Gribov
approach. Smooth logarithmic growth with the collision energy was established
for the parameter k, the mean rapidity density of charged particles produced by
a single string. It was obtained in the model by the fitting of the available
experimental data on charged particles rapidity density in $pp$ and $p\bar{p}$
collisions. The main effect of the model, a gradual onset of string
collectivity with the growth of collision energy, is accounted by a free
parameter {\beta} that is responsible in an effective way for the string fusion
phenomenon. Another free parameter, t, is used to define string tension. We
extract parameters {\beta} and t from the available experimental results on
<pt>-multiplicity correlation at nucleon collision energy $\sqrt{s}$ from 17
GeV to 7 TeV. Smooth dependence of both {\beta} and t on energy allows to make
predictions for the correlation behavior at the collision energy of 14 TeV. The
indications to the string interaction effects in high multiplicity events in
$pp$ collisions at the LHC energies are also discussed.


title:
Modeling and forecasting electricity spot prices: A functional data
  perspective

abstract:
  Classical time series models have serious difficulties in modeling and
forecasting the enormous fluctuations of electricity spot prices. Markov regime
switch models belong to the most often used models in the electricity
literature. These models try to capture the fluctuations of electricity spot
prices by using different regimes, each with its own mean and covariance
structure. Usually one regime is dedicated to moderate prices and another is
dedicated to high prices. However, these models show poor performance and there
is no theoretical justification for this kind of classification. The merit
order model, the most important micro-economic pricing model for electricity
spot prices, however, suggests a continuum of mean levels with a functional
dependence on electricity demand. We propose a new statistical perspective on
modeling and forecasting electricity spot prices that accounts for the merit
order model. In a first step, the functional relation between electricity spot
prices and electricity demand is modeled by daily price-demand functions. In a
second step, we parameterize the series of daily price-demand functions using a
functional factor model. The power of this new perspective is demonstrated by a
forecast study that compares our functional factor model with two established
classical time series models as well as two alternative functional data models.


title: Visualization of EIS at large potential range - new insights

abstract:
  Electrochemical Impedance Spectroscopy (EIS) is an experimental technique
largely used in electrochemistry and corrosion studies. However, almost all
published papers have just measured the EIS at the corrosion potential,
especially for corrosion purposes. This fact limits the capability of the
technique. In this paper, a Scilab software was developed which allows the
visualization of multiple EIS diagrams regarding the potential, exposure time
or experiment run. This procedure was applied to austenitic stainless steels in
two electrolytes from cathodic to anodic potentials. The EIS maps with two- or
three- dimensions were very useful to depict the evolution of the surface with
respect to the large range of applied potential. Some results are shown to
highlight the usefulness of this approach as a complementary technique to the
DC test performed at a given potential range.


title: Can Tests for Jumps be Viewed as Tests for Clusters?

abstract:
  We investigate the utility in employing asymptotic results related to a
clustering criterion to the problem of testing for the presence of jumps in
financial models. We consider the Jump Diffusion model for option pricing and
demonstrate how the testing problem can be reduced to the problem of testing
for the presence of clusters in the increments data. The overarching premise
behind the proposed approach is in the isolation of the increments with
considerably larger mean pertaining to the jumps from the ones which arise from
the diffusion component. Empirical verification is provided via simulations and
the test is applied to financial datasets.


title:
Remarks on low-energy approximations for Feynman path integration on the
  sphere

abstract:
  We shall define the oscillatory integrals by action integrals, Van Vleck
determinant and Dewitt curvature. Our method employs action integrals along the
shortest paths. We have the strong but not uniform convergence of time slicing
Feynman path integrals for low energy functions.


title: Nuclear astrophysics with radioactive ions at FAIR

abstract:
  The nucleosynthesis of elements beyond iron is dominated by neutron captures
in the s and r processes. However, 32 stable, proton-rich isotopes cannot be
formed during those processes, because they are shielded from the s-process
flow and r-process beta-decay chains. These nuclei are attributed to the p and
rp process.
  For all those processes, current research in nuclear astrophysics addresses
the need for more precise reaction data involving radioactive isotopes.
Depending on the particular reaction, direct or inverse kinematics, forward or
time-reversed direction are investigated to determine or at least to constrain
the desired reaction cross sections.
  The Facility for Antiproton and Ion Research (FAIR) will offer unique,
unprecedented opportunities to investigate many of the important reactions. The
high yield of radioactive isotopes, even far away from the valley of stability,
allows the investigation of isotopes involved in processes as exotic as the r
or rp processes.


title:
On hyperderivatives of single-cuspidal Drinfeld modular forms with
  A-expansions

abstract:
  We show that the Drinfeld modular forms with $A$-expansion that have been
constructed by the author are precisely the hyperderivatives of the subfamily
of single-cuspidal Drinfeld modular forms with $A$-expansions that remain
modular after hyperdifferentiation. In addition, we show that
Drinfeld-Poincar\'{e} series display a similar behavior with respect to
hyperdifferentiation, giving indirect evidence that the Drinfeld modular forms
with $A$-expansions are Drinfeld-Poincar\'{e} series. The Drinfeld-Poincar\'{e}
series that we consider generalize previous examples of such series by Gekeler,
and Gerritzen and van der Put.


title: Cascades in real interbank markets

abstract:
  We analyze cascades of defaults in an interbank loan market. The novel
feature of this study is that the network structure and the size distribution
of banks are derived from empirical data. We find that the ability of a
defaulted institution to start a cascade depends on an interplay of shock size
and connectivity. Further results indicate that the ability to limit default
risk by spreading the lending to many counterparts decreased with the financial
crisis. To evaluate the influence of the network structure on market stability,
we compare the simulated cascades from the empirical network with results from
different randomized network models. The results show that the empirical
network has non-random features, which cannot be captured by rewired networks.
The analysis also reveals that simulations assuming homogeneity for size of
banks and loan contracts dramatically overestimates the fragility of the
interbank market.


title: Constellation Optimization in the Presence of Strong Phase Noise

abstract:
  In this paper, we address the problem of optimizing signal constellations for
strong phase noise. The problem is investigated by considering three
optimization formulations, which provide an analytical framework for
constellation design. In the first formulation, we seek to design
constellations that minimize the symbol error probability (SEP) for an
approximate ML detector in the presence of phase noise. In the second
formulation, we optimize constellations in terms of mutual information (MI) for
the effective discrete channel consisting of phase noise, additive white
Gaussian noise, and the approximate ML detector. To this end, we derive the MI
of this discrete channel. Finally, we optimize constellations in terms of the
MI for the phase noise channel. We give two analytical characterizations of the
MI of this channel, which are shown to be accurate for a wide range of
signal-to-noise ratios and phase noise variances. For each formulation, we
present a detailed analysis of the optimal constellations and their performance
in the presence of strong phase noise. We show that the optimal constellations
significantly outperform conventional constellations and those proposed in the
literature in terms of SEP, error floors, and MI.


title: Theoretical Interpretations of the XYZ Mesons

abstract:
  The XYZ mesons are unexpected mesons containing a heavy quark-antiquark pair
that have been discovered during the last decade. The models for the XYZ mesons
that have been proposed include conventional quarkonium, quarkonium hybrids,
and quarkonium tetraquarks, whose four constituents can be clustered in several
possible ways. None of the models have provided a compelling pattern for the
XYZ mesons. The most promising theoretical approaches within QCD are lattice
QCD for the c c-bar mesons, lattice NRQCD for the b b-bar mesons, and the
Born-Oppenheimer approximation. The additional hints that will be provided by
future experiments guarantee the eventual solution of the XYZ puzzle.


title:
PINO - a tool for simulating neutron spectra resulting from the 7Li(p,n)
  reaction

abstract:
  The 7Li(p,n) reaction in combination with a 3.7 MV Van de Graaff accelerator
was routinely used at FZK to perform activation as well as time-of-flight
measurements with neutrons in the keV-region. Planned new setups with much
higher proton currents like SARAF and FRANZ and the availability of
liquid-lithium target technology will trigger a renaissance of this method. A
detailed understanding of the neutron spectrum is not only important during the
planning phase of an experiment, but also during for the analysis of activation
experiments. Therefore, the Monte-Carlo based program PINO (Protons In Neutrons
Out) was developed, which allows the simulation of neutron spectra considering
the geometry of the setup and the proton-energy distribution.


title:
Soft metrics and their Performance Analysis for Optimal Data Detection
  in the Presence of Strong Oscillator Phase Noise

abstract:
  In this paper, we address the classical problem of maximum-likelihood (ML)
detection of data in the presence of random phase noise. We consider a system,
where the random phase noise affecting the received signal is first compensated
by a tracker/estimator. Then the phase error and its statistics are used for
deriving the ML detector. Specifically, we derive an ML detector based on a
Gaussian assumption for the phase error probability density function (PDF).
Further without making any assumptions on the phase error PDF, we show that the
actual ML detector can be reformulated as a weighted sum of central moments of
the phase error PDF. We present a simple approximation of this new ML rule
assuming that the phase error distribution is unknown. The ML detectors derived
are also the aposteriori probabilities of the transmitted symbols, and are
referred to as soft metrics. Then, using the detector developed based on
Gaussian phase error assumption, we derive the symbol error probability (SEP)
performance and error floor analytically for arbitrary constellations. Finally
we compare SEP performance of the various detectors/metrics in this work and
those from literature for different signal constellations, phase noise
scenarios and SNR values.


title:
Impact of aerosols and adverse atmospheric conditions on the data
  quality for spectral analysis of the H.E.S.S. telescopes

abstract:
  The Earth's atmosphere is an integral part of the detector in ground-based
imaging atmospheric Cherenkov telescope (IACT) experiments and has to be taken
into account in the calibration. Atmospheric and hardware-related deviations
from simulated conditions can result in the mis-reconstruction of primary
particle energies and therefore of source spectra. During the eight years of
observations with the High Energy Stereoscopic System (H.E.S.S.) in Namibia,
the overall yield in Cherenkov photons has varied strongly with time due to
gradual hardware aging, together with adjustments of the hardware components,
and natural, as well as anthropogenic, variations of the atmospheric
transparency. Here we present robust data selection criteria that minimize
these effects over the full data set of the H.E.S.S. experiment and introduce
the Cherenkov transparency coefficient as a new atmospheric monitoring
quantity. The influence of atmospheric transparency, as quantified by this
coefficient, on energy reconstruction and spectral parameters is examined and
its correlation with the aerosol optical depth (AOD) of independent MISR
satellite measurements and local measurements of atmospheric clarity is
investigated.


title: Charge transport through graphene junctions with wetting metal leads

abstract:
  Graphene is believed to be an excellent candidate material for
next-generation electronic devices. However, one needs to take into account the
nontrivial effect of metal contacts in order to precisely control the charge
injection and extraction processes. We have performed transport calculations
for graphene junctions with wetting metal leads (metal leads that bind
covalently to graphene) using nonequilibrium Green's functions and density
functional theory. Quantitative information is provided on the increased
resistance with respect to ideal contacts and on the statistics of current
fluctuations. We find that charge transport through the studied two-terminal
graphene junction with Ti contacts is pseudo-diffusive up to surprisingly high
energies.


title:
Identifying Clouds over the Pierre Auger Observatory using Infrared
  Satellite Data

abstract:
  We describe a new method of identifying night-time clouds over the Pierre
Auger Observatory using infrared data from the Imager instruments on the
GOES-12 and GOES-13 satellites. We compare cloud identifications resulting from
our method to those obtained by the Central Laser Facility of the Auger
Observatory. Using our new method we can now develop cloud probability maps for
the 3000 km^2 of the Pierre Auger Observatory twice per hour with a spatial
resolution of ~2.4 km by ~5.5 km. Our method could also be applied to monitor
cloud cover for other ground-based observatories and for space-based
observatories.


title: Broken SU(4) Symmetry and The Fractional Quantum Hall Effect in Graphene

abstract:
  We construct a variational description for incompressible ground states and
charge gaps in the N = 0 LL of graphene which accounts for the 4-fold Landau
level degeneracy and for the short range interactions that break the SU(4)
spin-valley invariance. Our approach explains the experimental finding that
gaps at odd numerators are weak for 1<|\nu|<2 and strong for 0<|\nu|< 1. We
find that in the SU(4) invariant case the incompressible ground state at
|\nu|=1/3 is a three-component incompressible state, not the Laughlin state,
and discuss the competition between these two states in the presence of SU(4)
spin-valley symmetry breaking terms.


title: On the Erdos-Ko-Rado property for finite Groups

abstract:
  Let a finite group $G$ act transitively on a finite set $X$. A subset
$S\subseteq G$ is said to be {\it intersecting} if for any $s_1,s_2\in S$, the
element $s_1^{-1}s_2$ has a fixed point. The action is said to have the {\it
weak Erd\H{o}s-Ko-Rado} property, if the cardinality of any intersecting set is
at most $|G|/|X|$. If, moreover, any maximal intersecting set is a coset of a
point stabilizer, the action is said to have the {\it strong Erd\H{o}s-Ko-Rado}
property. In this paper we will investigate the weak and strong
Erd\H{o}s-Ko-Rado property and attempt to classify the groups whose all
transitive actions have these properties. In particular, we show that a group
with the weak Erd\H{o}s-Ko-Rado property is solvable and that a nilpotent group
with the strong Erd\H{o}s-Ko-Rado property is product of a $2$-group and an
abelian group of odd order.


title: The Hama Problem revisited: essential mixing in a free shear flow

abstract:
  We revisit a problem first introduced by Francis Hama in his 1962 Physics of
Fluids article 'Streaklines in a Perturbed Shear Flow.' Using a nascent
computer, Hama calculated streaklines and pathlines for an inviscid shear flow
containing a non-amplifying, sinusoidal, traveling-wave perturbation. He found
that this simple flow field and perturbation produced intuitive pathlines, yet,
the resulting streaklines were non-obvious and much more complex than the
pathlines. He used this work to stress the importance of understanding the
difference between flow visualization and measurement techniques, and that
different techniques may reveal different information regarding the true
character or behavior of the flow. This work revisits the Hama Problem and
presents the original findings in a fluid dynamics video prepared for the 2013
Gallery of Fluid Motion.


title: On the exact degree of multi-cyclic extension of $\mathbb{F}_{q}(t)$

abstract:
  Let $q$ be a power of a prime number $p$, $k=\mathbb{F}_{q}(t)$ be the
rational function field over finite field $\mathbb{F}_{q}$ and $K/k$ be a
multi-cyclic extension of prime degree. In this paper we will give an exact
formula for the degree of $K$ over $k$ by considering both Kummer and
Artin-Schreier cases.


title: Sets of integers that do not contain Hilbert cubes of dimension 3

abstract:
  We construct a set of positive integers A in {1,.., n} with |A|>> n^{2/3}
that does not contain Hilbert cubes of dimension 3.


title: One-dimensional photonic band gaps in optical lattices

abstract:
  The phenomenon of photonic band gaps in one-dimensional optical lattices is
reviewed using a microscopic approach. Formally equivalent to the transfer
matrix approach in the thermodynamic limit, a microscopic model is required to
study finite-size effects, such as deviations from the Bragg condition.
Microscopic models describing both scalar and vectorial light are proposed, as
well as for two- and three-level atoms. Several analytical results are compared
to experimental data, showing a good agreement.


title:
Variable Susceptibility With An Open Population: A Transport Equation
  Approach

abstract:
  Variable individual response to epidemics may be found within many contexts
in the study of infectious diseases (e.g., age structure or contact networks).
There are situations where the variability, in terms of epidemiological
parameter, cannot be neatly packaged along with other demographics of the
population like spatial location or life stage. Transport equations are a novel
method for handling this variability via a distributed parameter; where
particular parameter values are possessed by various proportions of the
population. Several authors (e.g., Kareva, Novozhilov, and Katriel) have
studied such systems in a closed population setting (no births/immigrations or
deaths/emigrations), but have cited restrictions to employing such methods when
entry and removal of individuals is added to the population. This paper
details, in the context of a simple susceptible-infectious-recovered (SIR)
epidemic, how the method works in the closed population setting and gives
conditions for initial, transient, and asymptotic results to be equivalent with
the nondistributed case. Additionally, I show how the method may be applied to
various forms of open SIR systems. Transport equations are used to transform an
infinite dimensional system for the open population case into a finite
dimensional system which is, at the very least, able to be numerically studied,
a model with direct inheritance of the distributed parameter is shown to be
qualitatively identical to the nondistributed case, and finally a model where
disease results in sterilization is fully analyzed.


title:
QuickLexSort: An efficient algorithm for lexicographically sorting
  nested restrictions of a database

abstract:
  Lexicographical sorting is a fundamental problem with applications to
contingency tables, databases, Bayesian networks, and more. A standard method
to lexicographically sort general data is to iteratively use a stable sort -- a
sort which preserves existing orders. Here we present a new method of
lexicographical sorting called QuickLexSort. Whereas a stable sort based
lexicographical sorting algorithm operates from the least important to most
important features, in contrast, QuickLexSort sorts from the most important to
least important features, refining the sort as it goes. QuickLexSort first
requires a one-time modest pre-processing step where each feature of the data
set is sorted independently. When lexicographically sorting a database,
QuickLexSort (including pre-processing) has comparable running time to using a
stable sort based approach. For a data base with $m$ rows and $n$ columns, and
a sorting algorithm running in time $O(mlog(m))$, a stable sort based
lexicographical sort and QuickLexSort will both take time $O(nmlog(m))$.
However in many applications one has the need to lexicographically sort nested
data, e.g.\ all possible sub-matrices up to a certain cardinality of columns.
In such cases we show QuickLexSort gives a performance improvement of a log
factor of the database length (rows in matrix) over using a standard stable
sort based approach. E.g.\ to sort all sub-matrices up to cardinality $k$,
QuickLexSort has running time $O(mn^k)$ whereas a stable sort based
lexicographical sort will take time $O(mlog(m)n^k)$. After the pre-processing
step that is run only once for the entire matrix, QuickLexSort has a running
time linear in the number of nested sub-matrices to sort. We conclude with an
application to Bayesian network scoring to detect epistasis using SNP marker
data.


title:
La variante infinit\'esimale de la formule des traces de Jacquet-Rallis
  pour les groupes lin\'eaires

abstract:
  We establish an infinitesimal version of the Jacquet-Rallis trace formula for
general linear groups. Our formula is obtained by integrating a kernel
truncated a la Arthur multiplied by the absolute value of the determinant to
the power $s \in \mathbb{C}$. It has a geometric side which is a sum of
distributions $I_{\mathfrak{o}}(s, \cdot)$ indexed by the invariants of the
adjoint action of $\mathrm{GL}_n(\mathrm{F})$ on
$\mathfrak{gl}_{n+1}(\mathrm{F})$ as well as a "spectral side" consisting of
the Fourier transforms of the aforementioned distributions. We prove that the
distributions $I_{\mathfrak{o}}(s, \cdot)$ are invariant and depend only on the
choice of the Haar measure on $\mathrm{GL}_n(\mathbb{A})$. For regular
semi-simple classes $\mathfrak{o}$, $I_{\mathfrak{o}}(s, \cdot)$ is a relative
orbital integral of Jacquet-Rallis. For classes $\mathfrak{o}$ called
relatively regular semi-simple, we express $I_{\mathfrak{o}}(s, \cdot)$ in
terms of relative orbital integrals regularised by means of zeta functions.


title:
Ethical Considerations when Employing Fake Identities in OSN for
  Research

abstract:
  Online Social Networks (OSNs) have rapidly become a prominent and widely used
service, offering a wealth of personal and sensitive information with
significant security and privacy implications. Hence, OSNs are also an
important - and popular - subject for research. To perform research based on
real-life evidence, however, researchers may need to access OSN data, such as
texts and files uploaded by users and connections among users. This raises
significant ethical problems. Currently, there are no clear ethical guidelines,
and researchers may end up (unintentionally) performing ethically questionable
research, sometimes even when more ethical research alternatives exist. For
example, several studies have employed `fake identities` to collect data from
OSNs, but fake identities may be used for attacks and are considered a security
issue. Is it legitimate to use fake identities for studying OSNs or for
collecting OSN data for research? We present a taxonomy of the ethical
challenges facing researchers of OSNs and compare different approaches. We
demonstrate how ethical considerations have been taken into account in previous
studies that used fake identities. In addition, several possible approaches are
offered to reduce or avoid ethical misconducts. We hope this work will
stimulate the development and use of ethical practices and methods in the
research of online social networks.


title:
Dynamically corrected gates for qubits with always-on Ising couplings:
  Error model and fault-tolerance with the toric code

abstract:
  We describe how a universal set of dynamically-corrected quantum gates can be
implemented using sequences of shaped decoupling pulses on any qubit network
forming a sparse bipartite graph with always-on Ising interactions. These
interactions are constantly decoupled except when they are needed for two-qubit
gates. We analytically study the error operators associated with the
constructed gates up to third order in the Magnus expansion, analyze these
errors numerically in the unitary time evolution of small qubit clusters, and
give a bound on high-order errors for qubits on a large square lattice. We
prove that with a large enough toric code the present gate set can be used to
implement a fault-tolerant quantum memory.

categories: quant-ph cond-mat.mes-hall physics.atm-clus physics.comp-ph


title: Theoretical Bounds on Mate-Pair Information for Accurate Genome Assembly

abstract:
  Over the past two decades, a series of works have aimed at studying the
problem of genome assembly: the process of reconstructing a genome from
sequence reads. An early formulation of the genome assembly problem showed that
genome reconstruction is NP-hard when framed as finding the shortest sequence
that contains all observed reads. Although this original formulation is very
simplistic and does not allow for mate-pair information, subsequent
formulations have also proven to be NP-hard, and/or may not be guaranteed to
return a correct assembly.
  In this paper, we provide an alternate perspective on the genome assembly
problem by showing genome assembly is easy when provided with sufficient
mate-pair information. Moreover, we quantify the number of mate-pair libraries
necessary and sufficient for accurate genome assembly, in terms of the length
of the longest repetitive region within a genome. In our analysis, we consider
an idealized sequencing model where each mate-pair library generates pairs of
error free reads with a fixed and known insert size at each position in the
genome.
  Even in this idealized model, we show that accurate genome reconstruction
cannot be guaranteed in the worst case unless at least roughly R/2L mate-pair
libraries are produced, where R is the length of the longest repetitive region
in the genome and L is the length of each read. On the other hand, if (R/L)+1
mate-pair libraries are provided, then a simple algorithm can be used to find a
correct genome assembly easily in polynomial time. Although (R/L)+1 mate-pair
libraries can be too much to produce in practice, the previous bounds only hold
in the worst case. In our last result, we show that if additional conditions
hold on a genome, a correct assembly can be guaranteed with only O(log (R/L))
mate-pair libraries.


title: Scaling Law for Recovering the Sparsest Element in a Subspace

abstract:
  We address the problem of recovering a sparse $n$-vector within a given
subspace. This problem is a subtask of some approaches to dictionary learning
and sparse principal component analysis. Hence, if we can prove scaling laws
for recovery of sparse vectors, it will be easier to derive and prove recovery
results in these applications. In this paper, we present a scaling law for
recovering the sparse vector from a subspace that is spanned by the sparse
vector and $k$ random vectors. We prove that the sparse vector will be the
output to one of $n$ linear programs with high probability if its support size
$s$ satisfies $s \lesssim n/\sqrt{k \log n}$. The scaling law still holds when
the desired vector is approximately sparse. To get a single estimate for the
sparse vector from the $n$ linear programs, we must select which output is the
sparsest. This selection process can be based on any proxy for sparsity, and
the specific proxy has the potential to improve or worsen the scaling law. If
sparsity is interpreted in an $\ell_1/\ell_\infty$ sense, then the scaling law
can not be better than $s \lesssim n/\sqrt{k}$. Computer simulations show that
selecting the sparsest output in the $\ell_1/\ell_2$ or thresholded-$\ell_0$
senses can lead to a larger parameter range for successful recovery than that
given by the $\ell_1/\ell_\infty$ sense.


title: Current-induced skyrmion dynamics in constricted geometries

abstract:
  Magnetic skyrmions, vortex-like swirling spin structures with quantized
topological number, observed in chiral magnets, are appealing for potential
applications in spintronics because it is possible to control their motion with
ultralow current density. In order to realise skyrmion-based spintronic
devices, it is essential to understand the skyrmion motions in confined
geometries. Here we show by micromagnetic simulations that the current-induced
motion of skyrmions in the presence of geometrical boundaries is very different
from that in an infinite plane. In a channel with finite width, the transverse
confinement results in steady state characteristics of the skyrmion velocity as
a function of current similar to those of domain walls in ferromagnets, whereas
the transient behaviour depends on the initial distance of the skyrmion from
the boundary. In addition, we show that single skyrmions can be created by
electric current in a simple constricted geometry of a plate-shaped specimen of
suitable size and geometry. These findings could guide the design of
skyrmion-based devices, in which skyrmions are used as information carriers.


title: A fully nonlinear "Generalised Monge-Amp\`ere" PDE on a torus

abstract:
  We prove an existence result for a "generalised" Monge-Amp\`ere equation
introduced earlier under some assumptions on a flat complex 3-torus. As an
application we prove the existence of Chern connections on certain kinds of
holomorphic vector bundles on complex 3-tori whose top Chern character forms
are given representatives.


title:
Double magnetic resonance and spin anisotropy in Fe-based
  superconductors due to static and fluctuating antiferromagnetic orders

abstract:
  Motivated by recent neutron scattering experiments in Fe-based
superconductors, we study how the magnetic resonance in the superconducting
state is affected by the simultaneous presence of either static or fluctuating
magnetic orders using the random phase approximation. We find that for the
underdoped materials with coexisting superconducting and antiferromagnetic
orders, spin rotational symmetry is explicitly broken at the ordering momentum
$Q_1 = (\pi,0)$. Only the longitudinal susceptibility exhibits the resonance
mode, whereas a spin-wave Goldstone mode develops in the transverse component.
Meanwhile, at the frustrated momentum $Q_2 = (0,\pi)$, the susceptibility
becomes isotropic in spin space and the magnetic resonance exists for both
components. Furthermore, the resonance energies at $Q_1$ and $Q_2$ have
distinct scales, which provides a natural explanation for the recently observed
double resonance peaks. In addition, we show that near optimal doping the
existence of strong magnetic fluctuations, which are modeled here via a
Gaussian mode, can still induce the spin anisotropy in the magnetic
susceptibility.


title: Symmetric identities of q-Euler polynomials

abstract:
  In this paper, we study some symmetric identities of q-Euler numbers and
polynomials. From these properties, we derive several identities of q-Euler
numbers and polynomials.


title:
MINT: Mutual Information based Transductive Feature Selection for
  Genetic Trait Prediction

abstract:
  Whole genome prediction of complex phenotypic traits using high-density
genotyping arrays has attracted a great deal of attention, as it is relevant to
the fields of plant and animal breeding and genetic epidemiology. As the number
of genotypes is generally much bigger than the number of samples, predictive
models suffer from the curse-of-dimensionality. The curse-of-dimensionality
problem not only affects the computational efficiency of a particular genomic
selection method, but can also lead to poor performance, mainly due to
correlation among markers. In this work we proposed the first transductive
feature selection method based on the MRMR (Max-Relevance and Min-Redundancy)
criterion which we call MINT. We applied MINT on genetic trait prediction
problems and showed that in general MINT is a better feature selection method
than the state-of-the-art inductive method mRMR.


title: New Determination of Muonium-Deuterium 1S-2S Isotope Shift

abstract:
  We report a new determination of muonium 1S-2S transition frequency and its
isotope shift with deuterium by recalibrating the iodine reference lines using
an optical frequency comb. The reference lines for the muonium and deuterium
1S-2S transitions are determined with a precision of 2.4*10^-10 and 1.7*10^-10
respectively. A new muonium-deuterium 1S-2S isotope-shift frequency is derived
from these references to be 11 203 464.9(9.2)(4.0) MHz, in agreement with an
updated bound-state quantum-electrodynamics prediction based on 2010
adjustments of Committee on Data for Science and Technology and 2.3 times
better in the systematic uncertainty than the previous best determination.


title:
Odd-even staggering of neutron radii for neutron-rich Mg isotopes in
  continuum Skyrme-Hartree-Fock-Bogoliubov theory

abstract:
  The self-consistent continuum Skyrme-Hartree-Fock-Bogoliubov theory
formulated with Green's function technique in the coordinate space is developed
to investigate odd-$A$ nuclei by incorporating the blocking effect. In a
calculation performed with the SLy4 parameter for the neutron-rich Mg isotopes
with $A=36-42$ around the neutron shell closure N=28, the odd-even staggering
in the neutron rms radius, i.e., a larger value in $^{39}$Mg than those in
$^{38}$Mg and $^{40}$Mg, is found. The large neutron radius in $^{39}$Mg is due
to the blocking effect on the pair correlation energy, for which the
configuration occupying the weakly-bound quasiparticle state $2p_{3/2}$ becomes
the ground state instead of the $1f_{7/2}$ configuration. Performing systematic
calculations with different Skyrme parameters we find that the ground state
configuration for the odd-$A$ Mg isotopes, and hence the odd-even staggering of
neutron radii, are sensitive to the details in the single-particle spectra,
especially the gap between orbits $1f_{7/2}$ and $2p_{3/2}$.


title:
On some Siegel threefold related to the tangent cone of the Fermat
  quartic surface

abstract:
  Let $Z$ be the quotient of the Siegel modular threefold $\mathcal{A}^{{\rm
sa}}(2,4,8)$ which has been studied by van Geemen and Nygaard. They gave an
implication that some 6-tuple $F_Z$ of theta constants which is in turn known
to be a Klingen type Eisenstein series of weight 3 should be related to a
holomorphic differential $(2,0)$-form on $Z$. The variety $Z$ is birationally
equivalent to the tangent cone of Fermat quartic surface in the title.
  In this paper we first compute the L-function of two smooth resolutions of
$Z$. One of these, denoted by $W$, is a kind of Igusa compactification such
that the boundary $\partial W$ is a strictly normal crossing divisor. The main
part of the L-function is described by some elliptic newform $g$ of weight 3.
Then we construct an automorphic representation $\Pi$ of ${\rm GSp}_2(\A)$
related to $g$ and an explicit vector $E_Z$ sits inside $\Pi$ which creates a
vector valued (non-cuspidal) Siegel modular form of weight $(3,1)$ so that
$F_Z$ coincides with $E_Z$ in $H^{2,0}(\partial W)$ under the Poincar\'e
residue map and various identifications of cohomologies.


title: Modeling scalar fields consistent with positive mass

abstract:
  This paper explores the conditions under which modified gravitational
theories admit the positive mass. Following Witten's spinor argument, it is
argued that a single condition should be imposed upon a gauge connection in the
super-covariant derivative. Under this condition, we present a simple formula
for the divergence of the Nester tensor in Einstein's gravity with general
source. Applying this prescription to the Einstein-scalar system, we find that
for a certain class of the gauge connection, a special kind of non-canonical
scalar-field theory admits the positivity property in addition to the ordinary
canonical scalar-field system. In both cases the scalar potential can be
written in terms of a superpotential. In the non-canonical case we obtain the
most general "BPS" solutions which preserve at least half of the supersymmetry.


title: Isotropic \Gamma_6 Ground State in Caged Compound NdRu2Zn20

abstract:
  The magnetic susceptibility $\chi$, the magnetization $M$, and the specific
heat $C$ were measured for the caged cubic compound NdRu$_2$Zn$_{20}$ at
temperatures down to 0.5 K in the magnetic field $H$ along the three
crystallographic principal axes, [100], [110], and [111]. The ferromagnetic
phase transition was observed at the Curie temperature $T_{\rm C}=1.9$ K in
both the temperature dependence of $\chi(T)$ and $C(T)$. Below $T_{\rm C}$, the
magnetization curves $M(H)$ show very weak magnetic anisotropy, and the $C(T)$
curves in the fields along the three principal axes show no magnetic anisotropy
both below and above $T_{\rm C}$. The easy direction of magnetization at 0.5 K
changes from the [111] direction in 0 T to the [110] diretion in 7 T. We
analyzed these characteristic behaviors theoretically taking into account the
crystalline-electric-field energy, the magnetic exchange interaction, and the
Zeeman energy. It was found that these features are originated from the
isotropic $\Gamma_6$ ground state mixing with the magnetic $\Gamma_8^{(1)}$
excited state. The temperature and the magnetic field dependences of $M(T,H)$
and $C(T,H)$ are quantitatively well analyzed by this theoretical calculation.


title:
Greenland Telescope (GLT) Project: "A Direct Confirmation of Black Hole
  with Submillimeter VLBI"

abstract:
  The GLT project is deploying a new submillimeter (submm) VLBI station in
Greenland. Our primary scientific goal is to image a shadow of the supermassive
black hole (SMBH) of six billion solar masses in M87 at the center of the Virgo
cluster of galaxies. The expected SMBH shadow size of 40-50 $\mu$as requires
superbly high angular resolution, suggesting that the submm VLBI would be the
only way to obtain the shadow image. The Summit station in Greenland enables us
to establish baselines longer than 9,000 km with ALMA in Chile and SMA in
Hawaii as well as providing a unique $u$--$v$ coverage for imaging M87. Our
VLBI network will achieve a superior angular resolution of about 20 $\mu$as at
350 GHz, corresponding to $\sim2.5$ times of the Schwarzschild radius of the
supermassive black hole in M87. We have been monitoring the atmospheric opacity
at 230 GHz since August. 2011; we have confirmed the value on site during the
winter season is comparable to the ALMA site thanks to high altitude of 3,200 m
and low temperature of $-50\degr$C. We will report current status and future
plan of the GLT project towards our expected first light on 2015--2016.


title: The discrete mKdV equation revisited: a Riemann-Hilbert approach

abstract:
  We study the plus and minus type discrete mKdV equation. Some different
symmetry conditions associated with two Lax pairs are introduced to derive the
matrix Riemann-Hilbert problem with zero. By virtue of regularization of the
Riemann-Hilbert problem, we obtain the complex and real solution to the plus
type discrete mKdV equation respectively. Under the gauge transformation
between the plus and minus type, the solutions of minus type can be obtained in
terms of the given plus ones.


title: Information-Based Physics: An Observer-Centric Foundation

abstract:
  It is generally believed that physical laws, reflecting an inherent order in
the universe, are ordained by nature. However, in modern physics the observer
plays a central role raising questions about how an observer-centric physics
can result in laws apparently worthy of a universal nature-centric physics.
Over the last decade, we have found that the consistent apt quantification of
algebraic and order-theoretic structures results in calculi that possess
constraint equations taking the form of what are often considered to be
physical laws. I review recent derivations of the formal relations among
relevant variables central to special relativity, probability theory and
quantum mechanics in this context by considering a problem where two observers
form consistent descriptions of and make optimal inferences about a free
particle that simply influences them. I show that this approach to describing
such a particle based only on available information leads to the mathematics of
relativistic quantum mechanics as well as a description of a free particle that
reproduces many of the basic properties of a fermion. The result is an approach
to foundational physics where laws derive from both consistent descriptions and
optimal information-based inferences made by embedded observers.


title: Why the Creative Process is Not Darwinian

abstract:
  Simonton (2006) makes the unwarranted assumption that nonmonotonicity
supports a Darwinian view of creativity. Darwin's theory of natural selection
was motivated by a paradox that has no equivalent in creative thought: the
paradox of how change accumulates when acquired traits are not inherited. To
describe a process of cumulative change in which acquired traits are retained
is outside of the scope of the theory of natural selection. Even the early
evolution of life itself (prior to genetically mediated template replication)
cannot be described by natural selection. Specifically, natural selection
cannot describe change of state that involves horizontal (Lamarckian) exchange,
or occurs through interaction with an incompletely specified context. It cannot
describe change wherein variants are evaluated sequentially, and wherein this
evaluation can itself change the state space and/or fitness function, because
no two variants are ever evaluated according to the same selection criterion.
Concerns are also raised as to the methodology used in Simonton's study.


title: Transverse wobbling-a collective mode in odd-A triaxial nuclei

abstract:
  The wobbling motion of a triaxial rotor coupled to a high-j quasiparticle is
treated semiclassi- cally. Longitudinal and transverse coupling regimes can be
distinguished depending on, respectively, whether the quasiparticle angular
momentum is oriented parallel or perpendicular to the rotor axis with the
largest moment of inertia. Simple analytical expressions for the wobbling
frequency and the electromagnetic E2 and M1 transition probabilities are
derived assuming rigid alignment of the quasiparticle with one of the rotor
axes and harmonic oscillations (HFA). Transverse wobbling is characterized by a
decrease of the wobbling frequency with increasing angular momentum. Two
examples for transverse wobbling, 163Lu and 135Pr, are studied in the framework
of the full triax- ial particle-rotor model and the HFA. The signature of
transverse wobbling, decreasing wobbling frequency and enhanced E2 inter-band
transitions, is found in agreement with experiment.


title:
An asymptotic approximation to the free-surface elevation around a
  cylinder in long waves

abstract:
  Strong nonlinear effects are known to contribute to the wave run-up caused
when a progressive wave impinges on a vertical surface piercing cylinder. The
magnitude of the wave run-up is largely dependent on the coupling of the
cylinder slenderness, $ka$, and wave steepness, $kA$, parameters. This present
work proposes an analytical solution to the free-surface elevation around a
circular cylinder in plane progressive waves. It is assumed throughout that the
horizontal extent of the cylinder is much smaller than the incident wavelength
and of the same order of magnitude as the incident wave amplitude. A
perturbation expansion of the velocity potential and free-surface boundary
condition is invoked and solved to third-order in terms of $ka$ and $kA$. The
validity of this approach is investigated through a comparison with canonical
second-order diffraction theory and existing experimental results. We find that
for small $ka$, the long wavelength theory is valid up to $kA \approx 0.16-0.2$
on the up wave side of the cylinder. However, this domain is significantly
reduced to $kA<0.06$ when an arbitrary position around the cylinder is
considered. An important feature of this work is an improved account of the
first-harmonic of the free-surface elevation over linear diffraction theory.


title:
Spin Splitting Induced by a Competition between Quantum Spin Hall Edge
  States and Valley Edge States

abstract:
  Strained graphene with lattice deformations has been demonstrated to give
rise to large pseudomagnetic fields and host many exotic properties. Here, we
propose a non-magnetic approach to realize a momentum-dependent out-of-plane
spin splitting in strained graphene nanoribbons with a moderate spin-orbit
coupling. This unique spin splitting distincts from the well-known Zeeman-type
spin splitting and the Rashba-type spin splitting. Our analysis indicates that
the competition between quantum spin Hall edge states and valley edge states in
the nanoribbon leads to the unique spin splitting. The quantum spin Hall states
at one edge of the nanoribbon are suppressed by the counterpropagating edge
modes induced by the pseudomagnetic field. At the opposite edge, the quantum
spin Hall states are not affected at all. Therefore, the degenerate quantum
spin Hall states of opposite spin orientation, which propagate at the two
opposite edges of the nanoribbon, are lifted. This result reveals a new method
to manipulate the spin degrees of freedom of electrons.


title: Beyond AMT: An Analysis of Crowd Work Platforms

abstract:
  While Amazon's Mechanical Turk (AMT) helped launch the paid crowd work
industry eight years ago, many new vendors now offer a range of alternative
models. Despite this, little crowd work research has explored other platforms.
Such near-exclusive focus risks letting AMT's particular vagaries and
limitations overly shape our understanding of crowd work and the research
questions and directions being pursued. To address this, we present a
cross-platform content analysis of seven crowd work platforms. We begin by
reviewing how AMT assumptions and limitations have influenced prior research.
Next, we formulate key criteria for characterizing and differentiating crowd
work platforms. Our analysis of platforms contrasts them with AMT, informing
both methodology of use and directions for future research. Our cross-platform
analysis represents the only such study by researchers for researchers,
intended to further enrich the diversity of research on crowd work and
accelerate progress.


title:
Global Well-Posedness and Large Time Asymptotic Behavior of Classical
  Solutions to the Compressible Navier-Stokes Equations with Vacuum

abstract:
  This paper concerns the global well-posedness and large time asymptotic
behavior of strong and classical solutions to the Cauchy problem of the
Navier-Stokes equations for viscous compressible barotropic flows in two or
three spatial dimensions with vacuum as far field density. For strong and
classical solutions, some a priori decay with rates (in large time) for both
the pressure and the spatial gradient of the velocity field are obtained
provided that the initial total energy is suitably {small.} Moreover, by using
these key decay rates and some analysis on the expansion rates of the essential
support of the density, we establish the global existence and uniqueness of
classical solutions (which may be of possibly large oscillations) in two
spatial dimensions, provided the smooth initial data are of small total energy.
In addition, the initial density can even have compact support. This, in
particular, yields the global regularity and uniqueness of the re-normalized
weak solutions of Lions-Feireisl to the two-dimensional compressible barotropic
flows for all adiabatic number $\gamma>1$ provided that the initial total
energy is small.


title:
Gauge invariance, massless modes and topology of gauge fields in
  multi-band superconductors

abstract:
  Multi-phase physics is a new physics of multi-gap superconductors. Multi-band
superconductors exhibit many interesting and novel properties. We investigate
the dynamics of the phase-difference mode and show that this mode yields a new
excitation mode. The phase-difference mode is represented as an abelian vector
field. There are massless modes when the number of gaps is greater than three
and the Josephson term is frustrated. The fluctuation of phase-difference modes
with non-trivial topology leads to the existence of a fractional-quantum flux
vortex in a magnetic field. A superconductor with a fractional-quantum flux
vortex is regarded as a topological superconductor with the integer Chern
number.


title:
Specific heat of segmented Heisenberg quantum spin chains in
  (Yb_{1-x}Lu_x)_4As_3

abstract:
  We report low-temperature specific heat, $C(T)$, measurements on
(Yb$_{1-x}$Lu$_x$)$_4$As$_3$ with $x=0.01$ and $x=0.03$, where nonmagnetic Lu
atoms are randomly distributed on antiferromagnetic $S=1/2$ Heisenberg chains
with $J/k_{\mathrm B}=28$ K. The observed reduction of $C$ below 15 K with
increasing $x$ is accurately described by quantum transfer matrix simulations
without any adjustable parameter, implying that the system is an excellent
experimental realization of segmented quantum spin chains. Finite-size effects
consistent with conformal-field theory predictions are leading to the formation
of an effective low-energy gap. The size of the gap increases with Lu content
and accounts for the impurity driven reduction of the specific heat. For both
concentrations our results verify experimentally the low temperature scaling
behavior established theoretically and also confirm the value of $J$ determined
from pure Yb$_4$As$_3$.


title: Synopsis of the workshop on humor and cognition

abstract:
  We summarize the proceedings of the Workshop on Humor and. The principal type
of humor considered, slippage humor, is defined and contrasted with
aggression-based humor. A variety of slippage humor, based on Hofstadter's
notion of a frame blend, is presented. Given that a frame is a small coherent
cluster of concepts pertaining to a single topic (similar to a script), a frame
blend results when elements extracted from two distinct frames are spliced
together to yield a new hybrid frame. Diverse ways of blending two frames can
produce varying degrees and types of humor. Studies of this phenomenon are
presented. We discuss the connection between frame blends and analogies,
focusing on the Copycat domain: an idealized microworld in which analogy making
can be studied and modeled on computer. It is shown how jokes can be mapped
into that domain, giving rise to a kind of abstract microworld humor. This
highlights the relationships amongst good jokes, defective analogies, and frame
blends. We discuss the notion that many jokes can share the same abstract
structure, and propose the term ur-joke for the most abstract level of a joke.
Several specific ur-jokes are presented, each with a set of fully fleshed-out
jokes based on it. We recount efforts at translating two jokes from one subject
matter to another in an attempt to determine whether a joke's funniness is due
more to its underlying ur-joke or its subject matter. We discuss the
relationship between the Raskin's overlapping-script theory of humor,
Hofstadter's frame-blend theory, and a theory that incorporates multiple-level
analysis of jokes. Finally, a speculative theory about the adaptive value of
humor is presented.


title:
Analysis of Particle Transfer by Periodic Lattice Modulation for
  Ultracold Fermionic Atom Systems in Three Dimensional Optical Lattice

abstract:
  We analyze a ultracold fermionic atom system in a three dimensional optical
lattice with a confinement harmonic potential, using the Hubbard model, and
time-dependent Gutzwiller variational approach for numerical calculation. Our
study is focused on the time evolution of the particle transfer when the
lattice potential is modulated by adding a periodic one. The choice of the
parameters such as the modulation frequency and amplitude and the particle
number affects the particle transfer. We calculate the time evolution of the
variance in the particle distribution, and show its dependence on the
parameters. The lattice modulation turns out to work effectively in order to
control the particle transfer, and will be a useful method in experiments for
fermionic atom systems.


title: Cognitive Mechanisms Underlying the Creative Process

abstract:
  This paper proposes an explanation of the cognitive change that occurs as the
creative process proceeds. During the initial, intuitive phase, each thought
activates, and potentially retrieves information from, a large region
containing many memory locations. Because of the distributed,
content-addressable structure of memory, the diverse contents of these many
locations merge to generate the next thought. Novel associations often result.
As one focuses on an idea, the region searched and retrieved from narrows, such
that the next thought is the product of fewer memory locations. This enables a
shift from association-based to causation-based thinking, which facilitates the
fine-tuning and manifestation of the creative work.


title: Stability and Delay Analysis of EPON Registration Protocol

abstract:
  The Ethernet passive optical network (EPON) has recently emerged as the
mainstream of broadband access networks. The registration process of EPON,
defined by the IEEE 802.3av standard, is a multi-point control protocol (MPCP)
within the media access control (MAC) layer. As with other contention-based
channel access methods, such as ALOHA and CSMA, stability and delay are
critical issues concerning the performances of implementing the protocol on
systems with finite channel capacity. In this paper, the registration process
of an EPON subscriber, called optical network units (ONUs), is modeled as a
discrete-time Markov chain, from which we derive the fundamental throughput
equation of EPON that characterizes the registration processes. The solutions
of this characteristic equation depend on the maximum waiting time. The aim of
our stability analysis is to pinpoint the region of the maximum waiting time
that can guarantee a stable registration throughput and a bounded registration
delay. For a maximum waiting time selected from the stable region, we obtain
the expression of registration delay experienced by an ONU attempting to
register. All analytic results presented in this paper were verified by
simulations.


title:
Color-kinematics duality and dimensional reduction for graviton emission
  in Regge limit

abstract:
  In this talk we review the work in [1,2,3] where we have studied the
applicability of the color-kinematics duality to the scattering of two
distinguishable scalar matter particles with one gluon emission in QCD, or one
graviton emission in Einstein gravity. We have shown that the duality works
well in the Regge limit under two different extensions of the gauge theory: the
introduction of a new scalar contact interaction and the relaxation of the
distinguishability of the scalars. Both modifications correspond to theories
obtained by dimensional reduction from higher-dimensional pure gauge theories.


title: Neutron activation of natural zinc samples at kT = 25 keV

abstract:
  The neutron-capture cross sections of 64Zn, 68Zn, and 70Zn have been measured
with the activation technique in a quasistellar neutron spectrum corresponding
to a thermal energy of kT = 25 keV. By a series of repeated irradiations with
different experimental conditions, an uncertainty of 3% could be achieved for
the 64Zn(n,g)65Zn cross section and for the partial cross section
68Zn(n,g)69Zn-m feeding the isomeric state in 69Zn. For the partial cross
sections 70Zn(n,g)71Zn-m and 70Zn(n,g)71Zn-g, which had not been measured so
far, uncertainties of only 16% and 6% could be reached because of limited
counting statistics and decay intensities. Compared to previous measurements on
64,68Zn, the uncertainties could be significantly improved, while the 70Zn
cross section was found to be two times smaller than existing model
calculations. From these results Maxwellian average cross sections were
determined between 5 and 100 keV. Additionally, the beta-decay half-life of
71Zn-m could be determined with significantly improved accuracy. The
consequences of these data have been studied by network calculations for
convective core He burning and convective shell C burning in massive stars.


title: Growth exponent for loop-erased random walk in three dimensions

abstract:
  We show the existence of the growth exponent for loop-erased random walk in
three dimensions.


title: The Far-IR View of Star and Planet Forming Regions

abstract:
  The far-IR range is a critical wavelength range to characterize the physical
and chemical processes that transform the interstellar material into stars and
planets. Objects in the earliest phases of stellar and planet evolution release
most of their energy at these long wavelengths. In this contribution we briefly
summarise some of the most relevant scientific advances achieved by the
Herschel Space Observatory in the field. We also anticipate those that will be
made possible by the large increase in sensitivity of SPICA cooled telescope.
It is concluded that only through sensitive far-IR observations much beyond
Herschel capabilities we will be able to constrain the mass, the energy budget
and the water content of hundreds of protostars and planet-forming disks.


title: Operator-valued spectral measures and large deviations

abstract: We study large deviation properties of random matricial spectral measures.


title: Distribution of irrational zeta values

abstract:
  In this paper we refine Ball-Rivoal's theorem by proving that for any odd
integer $a$ sufficiently large in terms of $\epsilon>0$, there exist $[
\frac{(1-\epsilon)\log a}{1+\log 2}]$ odd integers $s$ between 3 and $a$, with
distance at least $a^{\epsilon}$ from one another, at which Riemann zeta
function takes $\Q$-linearly independent values. As a consequence, if there are
very few integers $s$ such that $\zeta(s)$ is irrational, then they are rather
evenly distributed. The proof involves series of hypergeometric type estimated
by the saddle point method, and the generalization to vectors of Nesterenko's
linear independence criterion.


title:
Large in-plane deformation of RuO6 octahedron and ferromagnetism of bulk
  SrRuO3

abstract:
  SrRuO3 is a ferromagnetic metal with several unusual physical properties such
as zero thermal expansion below Tc, so-called Invar behavior. Another anomalous
feature is that the a-axis lattice constant is larger than the b-axis lattice
constant, a clear deviation from the predictions of the Glazer structural
description with rigid RuO6 octahedron motion. Using high resolution neutron
diffraction techniques, we show how these two structural anomalies arise from
the irregular in-plane deformation, i.e. plastic behavior of the RuO6
octahedron, a weak band Jahn-Teller distortion. We further demonstrate that the
ferromagnetic instability of SrRuO3 is related to the temperature-induced
localization of Ru 4d bands.


title:
Singular equivariant asymptotics and the momentum map. Residue formulae
  in equivariant cohomology

abstract:
  Let $M$ be a smooth manifold and $G$ a compact connected Lie group acting on
$M$ by isometries. In this paper, we study the equivariant cohomology of ${\bf
X}=T^\ast M$, and relate it to the cohomology of the Marsden-Weinstein reduced
space via certain residue formulae. In case that $\bf X$ is a compact
symplectic manifold with a Hamiltonian $G$-action, similar residue formulae
were derived by Jeffrey, Kirwan et al.


title:
Multi-Hamiltonian Structures on Spaces of Closed Equicentroaffine Plane
  Curves Associated to Higher KdV Flows

abstract:
  Higher KdV flows on spaces of closed equicentroaffine plane curves are
studied and it is shown that the flows are described as certain
multi-Hamiltonian systems on the spaces. Multi-Hamiltonian systems describing
higher mKdV flows are also given on spaces of closed Euclidean plane curves via
the geometric Miura transformation.


title:
Simulations of electric-dipole spin resonance for spin-orbit-coupled
  quantum dots in Overhauser field: fractional resonances and selection rules

abstract:
  We consider spin rotations in single- and two-electron quantum dots that are
driven by external AC electric field with two mechanisms that couple the
electron spatial motion and the spin degree of freedom: the spin-orbit
interaction and a random fluctuation of the Overhauser field due to nuclear
spin bath. We perform a systematic numerical simulation of the driven system
using a finite difference approach with an exact account taken for the
electron-electron correlation. The simulation demonstrates that the electron
oscillation in fluctuating nuclear field is translated into an effective
magnetic field during the electron wave packet motion. The effective magnetic
field drives the spin transitions according to the electric-dipole spin
resonance mechanism. We find distinct signatures of selection rules for direct
and higher-order transitions in terms of the spin-orbital symmetries of the
wave functions. The selection rules are violated by the random fluctuation of
the Overhauser field.


title: Online Unsupervised Feature Learning for Visual Tracking

abstract:
  Feature encoding with respect to an over-complete dictionary learned by
unsupervised methods, followed by spatial pyramid pooling, and linear
classification, has exhibited powerful strength in various vision applications.
Here we propose to use the feature learning pipeline for visual tracking.
Tracking is implemented using tracking-by-detection and the resulted framework
is very simple yet effective. First, online dictionary learning is used to
build a dictionary, which captures the appearance changes of the tracking
target as well as the background changes. Given a test image window, we extract
local image patches from it and each local patch is encoded with respect to the
dictionary. The encoded features are then pooled over a spatial pyramid to form
an aggregated feature vector. Finally, a simple linear classifier is trained on
these features.
  Our experiments show that the proposed powerful---albeit simple---tracker,
outperforms all the state-of-the-art tracking methods that we have tested.
Moreover, we evaluate the performance of different dictionary learning and
feature encoding methods in the proposed tracking framework, and analyse the
impact of each component in the tracking scenario. We also demonstrate the
flexibility of feature learning by plugging it into Hare et al.'s tracking
method. The outcome is, to our knowledge, the best tracker ever reported, which
facilitates the advantages of both feature learning and structured output
prediction.


title: Cohomological obstructions in locally variational field theories

abstract:
  We study cohomological obstructions to the existence of global conserved
quantities. In particular, we show that, if a given local variational problem
is supposed to admit global solutions, certain cohomology classes cannot appear
as obstructions. Vice versa, we obtain a new type of cohomological obstruction
to the existence of global solutions for a variational problem.


title:
Topological phase transitions in (Bi$_{1-x}$In$_{x})_2$Se$_3$ and
  (Bi$_{1-x}$Sb$_{x})_2$Se$_3$

abstract:
  We study the phase transition from a topological to a normal insulator with
concentration $x$ in (Bi$_{1-x}$In$_{x})_2$Se$_3$ and
(Bi$_{1-x}$Sb$_{x})_2$Se$_3$ in the Bi$_2$Se$_3$ crystal structure. We carry
out first-principles calculations on small supercells, using this information
to build Wannierized effective Hamiltonians for a more realistic treatment of
disorder. Despite the fact that the spin-orbit coupling (SOC) strength is
similar in In and Sb, we find that the critical concentration $x_{\rm c}$ is
much smaller in (Bi$_{1-x}$In$_{x})_2$Se$_3$ than in
(Bi$_{1-x}$Sb$_{x})_2$Se$_3$. For example, the direct supercell calculations
suggest that $x_{\rm c}$ is below 12.5% and above 87.5$%$ for the two alloys
respectively. More accurate results are obtained from realistic disordered
calculations, where the topological properties of the disordered systems are
understood from a statistical point of view. Based on these calculations, $x_c$
is around 17% for (Bi$_{1-x}$In$_{x})_2$Se$_3$, but as high as 78%-83% for
(Bi$_{1-x}$Sb$_{x})_2$Se$_3$. In (Bi$_{1-x}$Sb$_{x})_2$Se$_3$, we find that the
phase transition is dominated by the decrease of SOC, with a crossover or
"critical plateau" observed from around 78$%$ to 83$%$. On the other hand, for
(Bi$_{1-x}$In$_{x})_2$Se$_3$, the In 5$s$ orbitals suppress the topological
band inversion at low impurity concentration, therefore accelerating the phase
transition. In (Bi$_{1-x}$In$_{x})_2$Se$_3$ we also find a tendency of In atoms
to segregate.


title:
Improved Battery Models of an Aggregation of Thermostatically Controlled
  Loads for Frequency Regulation

abstract:
  Recently it has been shown that an aggregation of Thermostatically Controlled
Loads (TCLs) can be utilized to provide fast regulating reserve service for
power grids and the behavior of the aggregation can be captured by a stochastic
battery with dissipation. In this paper, we address two practical issues
associated with the proposed battery model. First, we address clustering of a
heterogeneous collection and show that by finding the optimal dissipation
parameter for a given collection, one can divide these units into few clusters
and improve the overall battery model. Second, we analytically characterize the
impact of imposing a no-short-cycling requirement on TCLs as constraints on the
ramping rate of the regulation signal. We support our theorems by providing
simulation results.


title:
Classification of Ordered Type Soliton Metric Lie Algebras by a
  Computational Approach

abstract:
  In this study, we classify some soliton nilpotent Lie algebras and possible
candidates in dimension 8 and 9 up to isomorphy. We focus on 1 < 2 < ::: < n
type of derivations where n is the dimension of the Lie algebras. We present
algorithms to generate possible algebra structures.


title: Electronic phase diagram in the new BiS2-based Sr1-xLaxFBiS2 system

abstract:
  In this paper, we systematically study the electron doping effect in a new
BiS2-based system Sr1-xLaxFBiS2(0<x<0.7) through multiple techniques of X-ray
diffraction, electrical transport, magnetic susceptibility, and Hall effect
measurements. The parent compound SrFBiS2 is found to possess a
semiconducting-like ground state, with thermally activation energy Eg=38 meV.
By the partial substitution of La for Sr, superconductivity emerges when x >
0.3, reaching its maximal superconducting transition temperature Tc=3.5 K at
x=0.55. In the normal state of superconducting samples, it is clearly seen that
there exists a crossover from metallic to semiconducting state below a
temperature Tmin, which shifts to lower temperatures with increasing La
content. Based on these measurements, the associated electronic phase diagram
of Sr1-xLaxFBiS2 system has thus been established.


title: On the Prolongations of Homogeneous Vector Bundles

abstract:
  In this paper, we introduce a study of prolongations of homogeneous vector
bundles. We give an alternative approach for the prolongation. For a given
homogeneous vector bundle E, we obtain a new homogeneous vector bundle. The
homogeneous structure and its corresponding representation are derived. The
prolongation of induced representation, which is an infinite dimensional linear
representation, is also defined.


title:
Quantum Monte Carlo Simulations for Stacked Spin Ladder Systems
  Containing Low Concentrations of Non-Magnetic Impurities; Application to the
  Low Temperature Broadening of NMR-Spectra in SrCu2O3

abstract:
  We present a Quantum Monte Carlo study for Heisenberg spin-1/2 two leg ladder
systems doped with non magnetic impurities. The simulations are applied to the
doped spin ladder compound SrCu2O3 doped with Zn, where a large broadening of
the 65Cu NMR lines has been observed in experiment at low temperatures but far
above the Neel temperature. We find that interladder-couplings with a sizeable
coupling in stacking direction are required to describe the line broadening,
which can not be explained by considering a single ladder only. Around a single
impurity, spin correlations cause an exponentially decaying antiferromagnetic
local magnetization in a magnetic field. We develop an effective model for the
local magnetization of systems with many randomly distributed impurities, with
few parameters which can be extracted out of QMC calculations with a single
impurity. The broadening arises from a drag effect, where the magnetization
around an impurity works as an effective field for spins on the neighboring
ladders, causing a non-exponentially decaying magnetization cloud around the
impurity. Our results show that even for impurity concentrations as small as x
= 0.001 and x = 0.0025, the broadening effect is large, in good quantitative
agreement with experiment. We also develop a simple model for the effective
interaction of two impurity spins.


title:
Current-induced spin polarization in graphene due to Rashba spin-orbit
  interaction

abstract:
  Spin polarization induced by an external electric field in graphene is
considered theoretically in the linear response regime. The graphene is assumed
to be deposited on a substrate which leads to the spin-orbit interaction of
Rashba type. The induced spin polarization is shown to be in the graphene plane
and perpendicular to the electric field. However, the spin polarization changes
sign when the Fermi level, whose position can be controlled by an external gate
voltage, crosses the Dirac points.


title: Conformal geometrodynamics regained: gravity from duality

abstract:
  There exist several ways of constructing general relativity from `first
principles': Einstein's original derivation, Lovelock's results concerning the
exceptional nature of the Einstein tensor from a mathematical perspective, and
Hojman-Kucha\v{r}-Teitelboim's derivation of the Hamiltonian form of the theory
from the symmetries of spacetime, to name a few. Here I propose a different set
of first principles to obtain general relativity in the canonical framework
without presupposing spacetime in any way. I first require consistent
propagation of scalar spatially covariant constraints. I find that up to a
certain order in derivatives (four spatial and two temporal), there are large
families of such consistently propagated constraints. Then I look for pairs of
such constraints that can gauge-fix each other and form a theory with two
dynamical degrees of freedom per \emph{space} point. This demand singles out
the ADM Hamiltonian either in i) CMC gauge, with arbitrary (finite, non-zero)
speed of light, and an extra term linear in York time, or ii) a gauge where the
Hubble parameter is conformally harmonic.


title: Electrostatic solitary waves in dusty pair-ion plasmas

abstract:
  The propagation of electrostatic waves in an unmagnetized collisionless
pair-ion plasma with immobile positively charged dusts is studied for both
large- and small-amplitude perturbations. Using a two-fluid model for
pair-ions, it is shown that there appear two linear ion modes, namely the
"fast" and "slow" waves in dusty pair-ion plasmas. The properties of these wave
modes are studied with different mass $(m)$ and temperature $(T)$ ratios of
negative to positive ions, as well as the effects of immobile charged dusts
$(\delta)$. For large-amplitude waves, the pseudopotential approach is
performed, whereas the standard reductive perturbation technique (RPT) is used
to study the small-amplitude Korteweg-de Vries (KdV) solitons. The profiles of
the pseudopotential, the large amplitude solitons as well as the dynamical
evolution of KdV solitons are numerically studied with the system parameters as
above. It is found that the pair-ion plasmas with positively charged dusts
support the propagation of solitary waves (SWs) with only the negative
potential. The results may be useful for the excitation of SWs in laboratory
dusty pair-ion plasmas, electron-free industrial plasmas as well as for
observation in space plasmas where electron density is negligibly small
compared to that of negative ions.


title: Strong Gravitational Lensing with Gauss-Bonnet correction

abstract:
  In this paper we investigate the strong gravitational lensing with
Gauss-Bonnet gravity. By considering the logarithmic term for deflection angle,
we obtain the deflection angle $\hat\alpha$ and corresponding parameters
$\bar{a}$ and $\bar{b}$. Finally, by using the relations between the
observables and lensing parameters, we estimate the observables such as,
$\theta_{\infty}$, $s$ and $r_m$, for the relativistic images in the
Gauss-Bonnet background.


title:
Monte Carlo simulation of light scattering in the atmosphere and effect
  of atmospheric aerosols on the point spread function

abstract:
  We present a Monte Carlo simulation for the scattering of light in the case
of an isotropic light source. The scattering phase functions are studied
particularly in detail to understand how they can affect the multiple light
scattering in the atmosphere. We show that although aerosols are usually in
lower density than molecules in the atmosphere, they can have a non-negligible
effect on the atmospheric point spread function. This effect is especially
expected for ground-based detectors when large aerosols are present in the
atmosphere.


title:
Degree-dependent network growth: From preferential attachment to
  explosive percolation

abstract:
  We present a simple model of network growth and solve it by writing down the
dynamic equations for its macroscopic characteristics like the degree
distribution and degree correlations. This allows us to study carefully the
percolation transition using a generating functions theory. The model considers
a network with a fixed number of nodes wherein links are introduced using
degree-dependent linking probabilities $p_k$. To illustrate the techniques and
support our findings using Monte-Carlo simulations, we introduce the exemplary
linking rule $p_k$ proportional to $k^{-\alpha}$, with $\alpha$ between -1 and
plus infinity. This parameter may be used to interpolate between different
regimes. For negative $\alpha$, links are most likely attached to high-degree
nodes. On the other hand, in case $\alpha>0$, nodes with low degrees are
connected and the model asymptotically approaches a process undergoing
explosive percolation.


title:
Quantum calculations of the carrier mobility in thin films: Methodology,
  Matthiessen's rule and comparison with semi-classical approaches

abstract:
  We discuss the calculation of the carrier mobility in silicon films within
the quantum Non-Equilibrium Green's Functions (NEGF) framework. We introduce a
new method for the extraction of the carrier mobility that is free from contact
resistance contamination, and provides accurate mobilities at a reasonable
cost, with minimal needs for ensemble averages. We then introduce a new
paradigm for the definition of the partial mobility $\mu_{M}$ associated with a
given elastic scattering mechanism "M", taking phonons (PH) as a reference
($\mu_{M}^{-1}=\mu_{PH+M}^{-1}-\mu_{PH}^{-1}$). We argue that this definition
makes better sense in a quantum transport framework as it is free from long
range interference effects that can appear in purely ballistic calculations. As
a matter of fact, these mobilities satisfy Matthiessen's rule for three
mechanisms [surface roughness (SR), remote Coulomb scattering (RCS) and
phonons] much better than the usual, single mechanism calculations. We also
discuss the problems raised by the long range spatial correlations in the RCS
disorder. Finally, we compare semi-classical Kubo-Greenwood (KG) and quantum
NEGF calculations. We show that KG and NEGF are in reasonable agreement for
phonon and RCS, yet not for SR. We point to possible deficiencies in the
treatment of SR scattering in KG, opening the way for further improvements.


title: Noetherianity up to symmetry

abstract:
  These lecture notes for the 2013 CIME/CIRM summer school Combinatorial
Algebraic Geometry deal with manifestly infinite-dimensional algebraic
varieties with large symmetry groups. So large, in fact, that subvarieties
stable under those symmetry groups are defined by finitely many orbits of
equations---whence the title Noetherianity up to symmetry. It is not the
purpose of these notes to give a systematic, exhaustive treatment of such
varieties, but rather to discuss a few "personal favourites": exciting examples
drawn from applications in algebraic statistics and multilinear algebra. My
hope is that these notes will attract other mathematicians to this vibrant area
at the crossroads of combinatorics, commutative algebra, algebraic geometry,
statistics, and other applications.


title: Electron Cloud Effects in Accelerators

abstract:
  We present a brief summary of various aspects of the electron-cloud effect
(ECE) in accelerators. For further details, the reader is encouraged to refer
to the proceedings of many prior workshops, either dedicated to EC or with
significant EC contents, including the entire "ECLOUD" series [122]. In
addition, the proceedings of the various flavors of Particle Accelerator
Conferences [23] contain a large number of EC-related publications. The ICFA
Beam Dynamics Newsletter series [24] contains one dedicated issue, and several
occasional articles, on EC. An extensive reference database is the LHC website
on EC [25].


title:
Prospects for detecting the 326.5 MHz redshifted 21 cm HI signal with
  the Ooty Radio Telescope (ORT)

abstract:
  Observations of the redshifted 21 cm HI fluctuations promise to be an
important probe of the post-reionization era. In this paper we calculate the
expected signal and foregrounds for the upgraded Ooty Radio Telescope (ORT)
which operates at frequency =326.5 MHz which corresponds to redshift z=3.35.
Assuming that the visibilities contain only the HI signal and system noise, we
show that a 3 sigma detection of the HI signal ~ 1 mk is possible at angular
scales 11 arc-minutes to 3 degree with ~ 1000 hours of observation. Foreground
removal is one of the major challenges for a statistical detection of the
redshifted 21 cm HI signal. We assess the contribution of different foregrounds
and find that the 326.5 MHz sky is dominated by the extragalactic point sources
at the angular scales of our interest. The expected total foregrounds are 4-5
orders of magnitude higher than the HI signal.


title: On inductively free Restrictions of Reflection Arrangements

abstract:
  Let W be a finite complex reflection group acting on the complex vector space
V and let A(W) = (A(W), V) be the associated reflection arrangement. In an
earlier paper by the last two authros, we classified all inductively free
reflection arrangements A(W). The aim of this note is to extend this work by
determining all inductively free restrictions of reflection arrangements.


title: General inner approximation of vector-valued functions

abstract:
  This paper addresses the problem of evaluating a subset of the range of a
vector-valued function. It is based on a work by Gold- sztejn and Jaulin which
provides methods based on interval analysis to address this problem when the
dimension of the domain and co-domain of the function are equal. This paper
extends this result to vector-valued functions with domain and co-domain of
different dimensions. This ex- tension requires the knowledge of the rank of
the Jacobian function on the whole domain. This leads to the sub-problem of
extracting an in- terval sub-matrix of maximum rank from a given interval
matrix. Three different techniques leading to approximate solutions of this
extraction are proposed and compared.


title:
Landmark and Intensity Based Registration with Large Deformations via
  Quasi-conformal Maps

abstract:
  Registration, which aims to find an optimal one-to-one correspondence between
different data, is an important problem in various fields. This problem is
especially challenging when large deformations occur. In this paper, we present
a novel algorithm to obtain diffeomorphic image or surface registrations with
large deformations via quasi-conformal maps. The basic idea is to minimize an
energy functional involving a Beltrami coefficient term, which measures the
distortion of the quasi-conformal map. The Beltrami coefficient effectively
controls the bijectivity and smoothness of the registration, even with very
large deformations. Using the proposed algorithm, landmark-based registration
between images or surfaces can be effectively computed. The obtained
registration is guaranteed to be diffeomorphic (1-1 and onto), even with a
large deformation or large number of landmark constraints. The proposed
algorithm can also be combined with matching intensity (such as image intensity
or surface curvature) to improve the accuracy of the registration. Experiments
have been carried out on both synthetic and real data. Results demonstrate the
efficacy of the proposed algorithm to obtain diffeomorphic registration between
images or surfaces.


title: Extensions of maps to M(Z_m,1)

abstract:
  We show that a Moore space M(Z_m,1) is an absolute extensor for finite
dimensional metrizable spaces of cohomological dimension dim_{Z_m} \leq 1.


title: Partial Sums Computation In Polar Codes Decoding

abstract:
  Polar codes are the first error-correcting codes to provably achieve the
channel capacity but with infinite codelengths. For finite codelengths the
existing decoder architectures are limited in working frequency by the partial
sums computation unit. We explain in this paper how the partial sums
computation can be seen as a matrix multiplication. Then, an efficient hardware
implementation of this product is investigated. It has reduced logic resources
and interconnections. Formalized architectures, to compute partial sums and to
generate the bits of the generator matrix k^n, are presented. The proposed
architecture allows removing the multiplexing resources used to assigned to
each processing elements the required partial sums.


title:
Status of the technologies for the production of the Cherenkov Telescope
  Array (CTA) mirrors

abstract:
  The Cherenkov Telescope Array (CTA) is the next generation very high-energy
gamma-ray observatory, with at least 10 times higher sensitivity than current
instruments. CTA will comprise several tens of Imaging Atmospheric Cherenkov
Telescopes (IACTs) operated in array-mode and divided into three size classes:
large, medium and small telescopes. The total reflective surface could be up to
10,000 m2 requiring unprecedented technological efforts. The properties of the
reflector directly influence the telescope performance and thus constitute a
fundamental ingredient to improve and maintain the sensitivity. The R&D status
of lightweight, reliable and cost-effective mirror facets for the CTA telescope
reflectors for the different classes of telescopes is reviewed in this paper.


title:
Measurement of D-meson production in p-Pb collisions with the ALICE
  detector

abstract:
  The ALICE Collaboration has measured the production of prompt D mesons in pPb
collisions at sqrt(s_NN) = 5.02 TeV in the rapidity range -0.04 < y_{cms} <
0.96 via the exclusive reconstruction of their hadronic decays D0->K-pi+,
D+->K- pi+ pi+, D*+->D0 pi+ and Ds->phi pi+. The pT-differential production
cross sections and the pT-dependent nuclear modification factors with respect
to a proton-proton reference, RpPb, are presented.


title:
The Design and Performance of a Scintillating-Fibre Tracker for the
  Cosmic-ray Muon Tomography of Legacy Nuclear Waste Containers

abstract:
  Tomographic imaging techniques using the Coulomb scattering of cosmic-ray
muons are increasingly being exploited for the non-destructive assay of
shielded containers in a wide range of applications. One such application is
the characterisation of legacy nuclear waste materials stored within industrial
containers. The design, assembly and performance of a prototype muon tomography
system developed for this purpose are detailed in this work. This muon tracker
comprises four detection modules, each containing orthogonal layers of
Saint-Gobain BCF-10 2mm-pitch plastic scintillating fibres. Identification of
the two struck fibres per module allows the reconstruction of the incoming and
Coulomb-scattered muon trajectories. These allow the container content, with
respect to the atomic number Z of the scattering material, to be determined
through reconstruction of the scattering location and magnitude. On each
detection layer, the light emitted by the fibre is detected by a single
Hamamatsu H8500 MAPMT with two fibres coupled to each pixel via dedicated
pairing schemes developed to ensure the identification of the struck fibre. The
PMT signals are read out to QDCs. The design and assembly of the detector
system are detailed and presented alongside results from performance studies
with data collected after construction. These results reveal high stability
during extended collection periods with detection efficiencies in the region of
80% per layer. Minor misalignments of millimetre order have been identified and
corrected in software. A first image reconstructed from a test configuration of
materials has been obtained using software based on the Maximum Likelihood
Expectation Maximisation algorithm. The results highlight the high spatial
resolution provided by the detector system. Clear discrimination between the
low, medium and high-Z materials assayed is also observed.


title:
Time delay in the recoiling valence-photoemission of Ar endohedrally
  confined in C$_{60}$

abstract:
  Effects of confinement and electron correlations on the relative time delay
between the 3s and 3p photoemissions of Ar confined endohedrally in C$_{60}$
are investigated using the time dependent local density approximation - a
method that is also found to mostly agree with recent time delay measurements
between the 3s and 3p subshells in atomic Ar. At energies in the neighborhood
of 3p Cooper minimum, correlations with C$_{60}$ electrons are found to induce
opposite temporal effects in the emission of Ar 3p hybridized symmetrically
versus that of Ar 3p hybridized antisymmetrically with C$_{60}$. A recoil-type
interaction model mediated by the confinement is found to best describe the
phenomenon.

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


title: Explaining Thermodynamic-Like Behaviour In Terms of Epsilon-Ergodicity

abstract:
  Why do gases reach equilibrium when left to themselves? The canonical answer,
originally proffered by Boltzmann, is that the systems have to be ergodic. This
answer is now widely regarded as flawed. We argue that some of the main
objections, in particular, arguments based on the KAM-theorem and the
Markus-Meyer theorem, are beside the point. We then argue that something close
to Boltzmann's proposal is true: gases behave thermodynamic-like if they are
epsilon-ergodic, i.e., ergodic on the phase space except for a small region of
measure epsilon. This answer is promising because there is evidence that
relevant systems are epsilon-ergodic.


title:
Segregated Vector Solutions for linearly coupled Nonlinear Schr\"odinger
  Systems

abstract:
  We consider the following system linearly coupled by nonlinear Schr\"odinger
equations in $\R^3$ $$ \left\{\begin{array}{ll} -\Delta
u_j+u_j=u^3_j-\va\sum\limits_{i\neq j}^N u_i,\{1cm}& x\in \R^3, \{0.2cm}\\
u_j\in H^1(\R^3),\quad j=1,\cdots,N, \end{array} \right. $$ where $\va\in\R$ is
a coupling constant. This type of system arises in particular in models in
nonlinear $N$-core fiber.
  We examine the effect of the linear coupling to the solution structure. When
$N=2,3$, for any prescribed integer $\ell\ge 2$, we construct a non-radial
vector solutions of segregated type, with two components having exactly $\ell$
positive bumps for $\va>0$ sufficiently small. We also give an explicit
description on the characteristic features of the vector solutions.


title: Dynamically generated darkness in the Dicke model

abstract:
  We study the dynamics of a driven Dicke model, where the collective spin is
rotated with a constant velocity around a fixed axis. The time evolution of the
mean photon number and of the atomic inversion is calculated using, on the one
hand, a numerical technique for the quantum dynamics of a small number of
two-level atoms, on the other hand, time-dependent mean-field theory for the
limit of a large number of atoms. We observe a reduction of the mean photon
number as compared to its equilibrium value. This dynamically generated
darkness is particularly pronounced slightly above the transition to a
superradiant phase. We attribute the effect to a slowing down of the motion in
the classical limit of a large ensemble and to an interplay of dynamic and
geometric phases in the quantum case.


title: Solvation Effects on Hole Mobility in the Poly G/Poly C Duplex

abstract:
  Theoretical calculations of solvation contribution to hole energy in a
polynucleotide chain give very low hole mobility values at zero temperature,
\mu < 10^{-3} cm^2/(V s). We calculated hole mobility at physiological
temperature for the Poly G/Poly C DNA duplex, which gave substantially larger
mobility values. Mobility over the temperature range 20-400 K was calculated.
Taking stacking interaction into account substantially increased hole mobility.


title:
A hierarchy of the quark masses in a top condensate model with multiple
  Higgses

abstract:
  We discuss the quark masses in a top condensate model where not only two
quark but also four quark composite states may exist. We show that the presence
of the top color group SU(3)_1\times SU(3)_2 with the correct non anomalous
quark representations can justify even in the absence of additional technicolor
interactions a hierarchy of the quark masses where the light quark masses have
the same size, the charm and bottom masses are higher and similar and the top
is the heaviest.


title: Continuous-variable qubit on an optical transverse mode

abstract:
  Continuous-variable (CV) qubits can be created on an optical longitudinal
mode in which quantum information is encoded by the superposition of even and
odd Schroedinger's cat states with quadrature amplitude. Based on the analogous
features of paraxial optics and quantum mechanics, we propose a system to
generate and detect CV qubits on an optical transverse mode. As a
proof-of-principle experiment, we generate six CV qubit states and observe
their probability distributions in position and momentum space. This enabled us
to prepare a non-Gaussian initial state for CV quantum computing. Other
potential applications of the CV qubit include adiabatic control of a beam
profile, phase shift keying on transverse modes, and quantum cryptography using
CV qubit states.


title:
Random spanning forests, Markov matrix spectra and well distributed
  points

abstract:
  This paper is a variation on the uniform spanning tree theme. We use random
spanning forests to solve the following problem: for a Markov process on a
finite set of size $n$, find a probability law on the subsets of any given size
$m \leq n$ with the property that the mean hitting time of such a random target
does not depend on the starting point of the random walk. We then explore the
connection between random spanning forests and infinitesimal generator
spectrum. In particular we give an almost probabilistic proof of an algebraic
result due to Micchelli and Willoughby and used by Fill and Miclo to study the
convergence to equilibrium of reversible Markov chains. We finally introduce
some related fragmentation and coalescence processes, emphasizing algorithmic
aspects, and give an extension of Burton and Pemantle transfer current theorem
to the non reversible case.


title: NNLO contributions to jet photoproduction and determination of \alpha_s

abstract:
  We present the first calculation of inclusive jet photoproduction with
next-to-next-to-leading order (NNLO) contributions, obtained from a unified
threshold resummation formalism. The leading coefficients for direct
photoproduction are computed analytically. Together with the coefficients
pertinent to parton-parton scattering, they are shown to agree with those
appearing in our full next-to-leading order calculations. For hadron-hadron
scattering, numerical agreement is found with a previous calculation of jet
production at the Tevatron. We show that the direct and resolved NNLO
contributions considerably improve the description of final ZEUS data on jet
photoproduction and that the error on the determination of the strong coupling
constant is significantly reduced.


title: Magnetic fields along the pre-main-sequence phase

abstract:
  In this contribution I review some of the major work that have been
undertaken in the last decade to study the magnetic fields in intermediate-mass
pre-main sequence stars, with the goal of understanding the origin of the
magnetic fields detected in the chemically peculiar Ap/Bp stars, and testing
the fossil field theory.


title: Four-connected triangulations of planar point sets

abstract:
  In this paper, we consider the problem of determining in polynomial time
whether a given planar point set $P$ of $n$ points admits 4-connected
triangulation. We propose a necessary and sufficient condition for recognizing
$P$, and present an $O(n^3)$ algorithm of constructing a 4-connected
triangulation of $P$. Thus, our algorithm solves a longstanding open problem in
computational geometry and geometric graph theory. We also provide a simple
method for constructing a noncomplex triangulation of $P$ which requires
$O(n^2)$ steps. This method provides a new insight to the structure of
4-connected triangulation of point sets.


title:
Light beam dynamics in materials with radially-inhomogeneous thermal
  conductivity

abstract:
  We study the properties of bright and vortex solitons in thermal media with
nonuniform thermal conductivity and homogeneous refractive index, whereby the
local modulation of the thermal conductivity strongly affects the entire
refractive index distribution. While regions where the thermal conductivity is
increased effectively expel light, self-trapping may occur in the regions with
reduced thermal conductivity, even if such regions are located close to the
material boundary. As a result, strongly asymmetric self-trapped beams may form
inside a ring with reduced thermal conductivity and perform persistent rotary
motion. Also, such rings are shown to support stable vortex solitons, which may
feature strongly non-canonical shapes.


title:
Principles of a 2nd quantum mechanics - indeterminism, non-locality,
  unification

abstract:
  A qualitative but formalized representation of microstates is first
established quite independently of the quantum mechanical mathematical
formalism, exclusively under epistemological-operational-methodological
constraints. Then, using this representation as a
reference-and-imbedding-structure, the foundations of an intelligible
reconstruction of the Hilbert-Dirac formulation of Quantum Mechanics is
developed. Inside this reconstruction the measurement problem as well as the
other major problems raised by the quantum mechanical formalism, dissolve.


title:
Sensitivity analysis for stochastic chemical reaction networks with
  multiple time-scales

abstract:
  Stochastic models for chemical reaction networks have become very popular in
recent years. For such models, the estimation of parameter sensitivities is an
important and challenging problem. Sensitivity values help in analyzing the
network, understanding its robustness properties and also in identifying the
key reactions for a given outcome. Most of the methods that exist in the
literature for the estimation of parameter sensitivities, rely on Monte Carlo
simulations using Gillespie's stochastic simulation algorithm or its variants.
It is well-known that such simulation methods can be prohibitively expensive
when the network contains reactions firing at different time-scales, which is a
feature of many important biochemical networks. For such networks, it is often
possible to exploit the time-scale separation and approximately capture the
original dynamics by simulating a "reduced" model, which is obtained by
eliminating the fast reactions in a certain way. The aim of this paper is to
tie these model reduction techniques with sensitivity analysis. We prove that
under some conditions, the sensitivity values of the reduced model can be used
to approximately recover the sensitivity values for the original model. Through
an example we illustrate how our result can help in sharply reducing the
computational costs for the estimation of parameter sensitivities for reaction
networks with multiple time-scales. To prove our result, we use coupling
arguments based on the random time change representation of Kurtz. We also
exploit certain connections between the distributions of the occupation times
of Markov chains and multi-dimensional wave equations.