title: Computing Clebsch-Gordan matrices with applications in elasticity theory

abstract:
  We provide an algorithm of computing Clebsch-Gordan coefficients for
irreducible representations, with integer weights, of the rotation group SO(3)
and demonstrate the convenience of this algorithm for constructing new (to our
knowledge) models in anisotropic elasticity theory.


title: Augmented Reality in ICT for Minimum Knowledge Loss

abstract:
  Informatics world digitizes the human beings, with the contribution made by
all the industrial people. In the recent survey it is proved that people are
not accustomed or they are not able to access the electronic devices to its
extreme usage. Also people are more dependent to the technologies and their
day-to-day activities are ruled by the same. In this paper we discuss on one of
the advanced technology which will soon rule the world and make the people are
more creative and at the same time hassle-free. This concept is introduced as
6th sense technology by an IIT, Mumbai student who is presently Ph.D., scholar
in MIT, USA. Similar to this research there is one more research going on under
the title Augmented Reality. This research makes a new association with the
real world to digital world and allows us to share and manipulate the
information directly with our mental thoughts. A college which implements state
of the art technology for teaching and learning, Higher College of Technology,
Muscat, (HCT) tries to identify the opportunities and limitations of
implementing this augmented reality for teaching and learning. The research
team of HCT, here, tries to give two scenarios in which augmented reality can
fit in. Since this research is in the conceptual level we are trying to
illustrate the history of this technology and how it can be adopted in the
teaching environment


title: Affinity of Cherednik algebras on projective space

abstract:
  We give sufficient conditions for the affinity of Etingof's sheaves of
Cherednik algebras on projective space. To do this we introduce the notion of
pull-back of modules under certain flat morphisms.


title: Three-nucleon forces and nuclei at the extremes

abstract:
  Neutron-rich nuclei become increasingly sensitive to three-nucleon forces.
These components of nuclear forces are at the forefront of theoretical
developments based on effective field theories of quantum chromodynamics. We
discuss our understanding of three-nucleon forces and their impact on exotic
nuclei, and show how new measurements test and constrain them. Three-nucleon
forces therefore provide an exciting link between theoretical and experimental
nuclear physics frontiers.


title: Generalization of neighborhood complexes

abstract:
  We introduce the notion of r-neighborhood complex for a positive integer r,
which is a natural generalization of Lovasz neighborhood complex. The
topologies of these complexes give some obstructions of the existence of graph
maps. We applied these complexes to prove the nonexistence of graph maps about
Kneser graphs. We prove that the fundamental groups of r-neighborhood complexes
are closely related to the (2r)-fundamental groups defined in the author's
previous paper.


title:
Geiringer Theorems: From Population Genetics to Computational
  Intelligence, Memory Evolutive Systems and Hebbian Learning

abstract:
  The classical Geiringer theorem addresses the limiting frequency of
occurrence of various alleles after repeated application of crossover. It has
been adopted to the setting of evolutionary algorithms and, a lot more
recently, reinforcement learning and Monte-Carlo tree search methodology to
cope with a rather challenging question of action evaluation at the chance
nodes. The theorem motivates novel dynamic parallel algorithms that are
explicitly described in the current paper for the first time. The algorithms
involve independent agents traversing a dynamically constructed directed graph
that possibly has loops. A rather elegant and profound category-theoretic model
of cognition in biological neural networks developed by a well-known French
mathematician, professor Andree Ehresmann jointly with a neurosurgeon, Jan Paul
Vanbremeersch over the last thirty years provides a hint at the connection
between such algorithms and Hebbian learning.


title:
On the Generalization Ability of Online Learning Algorithms for Pairwise
  Loss Functions

abstract:
  In this paper, we study the generalization properties of online learning
based stochastic methods for supervised learning problems where the loss
function is dependent on more than one training sample (e.g., metric learning,
ranking). We present a generic decoupling technique that enables us to provide
Rademacher complexity-based generalization error bounds. Our bounds are in
general tighter than those obtained by Wang et al (COLT 2012) for the same
problem. Using our decoupling technique, we are further able to obtain fast
convergence rates for strongly convex pairwise loss functions. We are also able
to analyze a class of memory efficient online learning algorithms for pairwise
learning problems that use only a bounded subset of past training samples to
update the hypothesis at each step. Finally, in order to complement our
generalization bounds, we propose a novel memory efficient online learning
algorithm for higher order learning problems with bounded regret guarantees.


title: Linear responses of D0-branes via gauge/gravity correspondence

abstract:
  We study linear responses of D0-branes in the low frequency region by using
gauge/gravity correspondence. The dynamics of the D0-branes is described by
Matrix theory with finite temperature, which is dual to a near extremal
D0-brane black hole solution. We analyze the tensor mode and vector modes of a
stress tensor and a Ramond-Ramond 1-form current of Matrix theory. Then, we
show that if a cutoff surface is close to a horizon of the D0-brane black hole,
the linear responses take forms similar to the hydrodynamic stress tensor and
current on S^8. By taking a Rindler limit, those linear responses come to obey
the hydrodynamics exactly, which is consistent with previous works on a Rindler
fluid. We also show that if the cutoff surface is far from the horizon, the
linear responses do not take the forms of the hydrodynamic stress tensor and
current on S^8. Especially, we find that the vector modes no longer possess a
diffusion pole in the low frequency region, which indicates that the linear
responses of the D0-branes cannot be explained by hydrodynamics.


title: Spontaneously Generated Inhomogeneous Phases via Holography

abstract:
  We discuss a holographic model consisting of a $U(1)$ gauge field and a
scalar field coupled to a charged AdS black hole under a spatially homogeneous
chemical potential. By turning on a higher-derivative interaction term between
the $U(1)$ gauge field and the scalar field, a spatially dependent profile of
the scalar field is generated spontaneously. We calculate the critical
temperature at which the transition to the inhomogeneous phase occurs for
various values of the parameters of the system. We solve the equations of
motion below the critical temperature, and show that the dual gauge theory on
the boundary spontaneously develops a spatially inhomogeneous charge density.


title:
Atomic and molecular dynamics triggered by ultrashort light pulses on
  the atto- to picosecond time scale

abstract:
  Time-resolved investigations of ultrafast electronic and molecular dynamics
were not possible until recently. The typical time scale of these processes is
in the picosecond to attosecond realm. The tremendous technological progress in
recent years made it possible to generate ultrashort pulses, which can be used
to trigger, to watch, and to control atomic and molecular motion. This tutorial
focuses on experimental and theoretical advances which are used to study the
dynamics of electrons and molecules in the presence of ultrashort pulses. In
the first part, the rotational dynamics of molecules, which happens on
picosecond and femtosecond time scales, is reviewed. Well-aligned molecules are
particularly suitable for angle-dependent investigations like x-ray diffraction
or strong-field ionization experiments. In the second part, the ionization
dynamics of atoms is studied. The characteristic time scale lies, here, in the
attosecond to few-femtosecond regime. Although a one-particle picture has been
successfully applied to many processes, many-body effects do constantly occur.
After a broad overview of the main mechanisms and the most common tools in
attosecond physics, examples of many-body dynamics in the attosecond world
(e.g., in high-harmonic generation and attosecond transient absorption
spectroscopy) are discussed.


title:
On the dimensions of the oscillator algebras induced by orthogonal
  polynomials

abstract:
  There is a generalized oscillator algebra associated with every class of
orthogonal polynomials $\{\Psi_n(x)\}_{n=0}^{\infty}$, on the real line,
satisfying a three term recurrence relation
$x\Psi_n(x)=b_n\Psi_{n+1}(x)+b_{n-1}\Psi_{n-1}(x), \Psi_0(x)=1, b_{-1}=0$. This
note presents necessary and safficient conditions on $b_n$ for such algebras to
be of finite dimension. As examples, we discuss the dimensions of oscillator
algebras associated with Hermite, Legendre and Gegenbauer polynomials. In
addition we shall also discuss the dimensions of some generalized deformed
oscillator algebras. Some remarks on the dimensions of oscillator algebras
associated with multi-boson systems are also presented.


title:
Microwave-induced zero-resistance" states and second-harmonic generation
  in an ultraclean two-dimensional electron gas

abstract:
  Microwave-induced resistance oscillations (MIRO) and "zero-resistance" states
(ZRS) were discovered in ultraclean two-dimensional electron systems in
2001-2003 and have attracted great interest from researchers. A comprehensive
theory of these phenomena was developed in 2011: It was shown that all
experimentally observed dependencies can be naturally explained by the
influence of the ponderomotive forces which arise in the near-contact regions
of the two-dimensional electron gas under the action of microwaves. Now we show
that the same near-contact physical processes should lead to another nonlinear
electrodynamic phenomenon - the second-harmonic generation. We calculate the
frequency, magnetic field, mobility, and power dependencies of the
second-harmonic intensity and show that it can be as large as ~ 0.5 mW/cm2
under realistic experimental conditions. A part of this paper is devoted to a
further discussion of the MIRO/ZRS phenomena: we explain how the
ponderomotive-force theory explains different experimental details, including
those which were not known in 2011, and critically discuss alternative
theories.


title:
Partially coherent sources which produce the same far zone optical force
  as a laser beam

abstract:
  On applying a theorem previously derived by Wolf and Collett, we demonstrate
that partially coherent Gaussian Schell model uctuating sources (GSMS) produce
exactly the same optical forces as a fully coherent laser beam. We also show
that this kind of sources helps to control the light-matter interaction in
biological samples which are very sensitive to thermal heating induced by
higher power intensities; and hence the invasiveness of the manipulation. This
is a consequence of the fact that the same photonic force can be obtained with
a low intensity GSMS as with a high intensity laser beam.


title:
Comment on "Direct Measurement of Auger Electrons Emitted from a
  Semiconductor Light-Emitting Diode under Electrical Injection: Identification
  of the Dominant Mechanism for Efficiency Droop" [Phys. Rev. Lett. 110, 177406
  (2013)]

abstract:
  In a recent letter [Phys. Rev. Lett. 110, 177406 (2013)], presenting a
spectroscopic study of the electrons emitted from the GaN p-cap of a
forward-biased InGaN/GaN light-emitting diode (LED), the authors observed at
least two distinct peaks in the electron energy distribution curves (EDCs),
separated by about 1.5 eV, and concluded that the only viable explanation for
the higher-energy peak was Auger recombination in the LED active region. We
present full-band Monte Carlo simulations suggesting that the higher-energy
peaks in the measured EDCs are probably uncorrelated with the carrier
distribution in the active region. This would not imply that Auger
recombination, and possibily Auger-induced leakage, play a negligible role in
LED droop, but that an Auger signature cannot be recovered from the experiment
performed on the LED structure under study. We discuss, as an alternative
explanation for the observed EDCs, carrier heating by the electric field in the
band-bending region.


title: Study of Neutrino Oscillations in the OPERA Experiment

abstract:
  The OPERA experiment has been designed to perform the first detection of
neutrino oscillations in direct appearance mode in the $\nu_{\mu}\to\nu_{\tau}$
channel, through the detection of the tau lepton produced in charged current
interaction on an event by event basis. The detector is hybrid, being made of
an emulsion/lead target and of electronic detectors. It exploited the CNGS muon
neutrino beam from CERN to Gran Sasso, 730 km from the source. Runs with CNGS
neutrinos were successfully carried out from 2008 to 2012. We report on the
large data sample analysed so far and give our results on the search for
$\nu_{\mu}\to\nu_{\tau}$ and $\nu_{\mu}\to\nu_{e}$ oscillations.


title:
Harmonic maps of finite uniton type into non-compact inner symmetric
  spaces

abstract:
  Due to the efforts of many mathematicians, there has been a classification of
harmonic two-spheres into compact (semi-simple) Lie groups as well as compact
inner symmetric spaces. Such harmonic maps have been shown by Uhlenbeck,
Burstall-Guest, Segal to have a finite uniton number. Moreover, the monodromy
representation was shown to be trivial and to be polynomial in the loop
parameter. We will introduce a general definition according to which such maps
are called to be of finite uniton type.
  This paper aims to generalize results of [2] to harmonic maps of finite
uniton type into a non-compact inner symmetric space. For this purpose, we
first recall some basic results about harmonic maps of finite uniton type. Then
we interpret the work of Burstall and Guest on harmonic maps of finite uniton
type into compact (semi-simple) Lie groups in terms of the language of the DPW
method. Moreover, to make the work of Burstall and Guest applicable to our
setting we show that a harmonic map into a non-compact inner symmetric space
$G/K$ shares the normalized potential as well as the meromorphic extended
framing with a harmonic map into $U/(U\cap K^{\mathbb{C}})$, the compact dual
of $G/K$. Thus we reduce the description of harmonic maps of finite uniton type
into a non-compact inner symmetric space to the description of harmonic maps of
finite uniton type into a compact inner symmetric space.
  Our main goal for the study of such harmonic maps is to provide a
classification of Willmore two-spheres (whose conformal Gauss maps take value
in the non-compact symmetric space $SO^+(1,n+3)/SO(1,3)\times SO(n)$).
  We will finish this paper by presenting the coarse classification of Willmore
two-spheres in terms of their conformal Gauss maps [28] as well as examples of
Willmore surfaces constructed by using [13] and the results of this paper.


title: Quantum Transport Theory with the Nonequilibrium Coherent Potentials

abstract:
  Since any realistic electronic device has some degree of disorder, predicting
disorder effects in quantum transport is a critical problem. Here we report the
theory of nonequilibrium coherent potential approximation (NECPA) for analyzing
disorder effects in nonequilibrium quantum transport of nanoelectronic devices.
The NECPA is formulated by contour ordered nonequilibrium Green's function
(NEGF) where the disorder average is carried out within the coherent potential
approximation on the complex-time contour. We have derived a set of new rules
that supplement the celebrated Langreth theorem and, as a whole, the
generalized Langreth rules allow us to derive NECPA equations for real time
Green's functions. The solution of NECPA equations provide the disorder
averaged nonequilibrium density matrix as well as other relevant quantities for
quantum transport calculations. We establish the excellent accuracy of NECPA by
comparing its results to brute force numerical calculations of disordered
tight-binding models. Moreover, the connection of NECPA equations which are
derived on the complex-time contour, to the nonequilibrium vertex correction
theory which is derived on the real-time axis, is made. As an application, we
demonstrate that NECPA can be combined with density functional theory to enable
analysis of nanoelectronic device physics from atomistic first principles.


title: On the K{\L}R conjecture in random graphs

abstract:
  The K{\L}R conjecture of Kohayakawa, {\L}uczak, and R\"odl is a statement
that allows one to prove that asymptotically almost surely all subgraphs of the
random graph G_{n,p}, for sufficiently large p : = p(n), satisfy an embedding
lemma which complements the sparse regularity lemma of Kohayakawa and R\"odl.
We prove a variant of this conjecture which is sufficient for most known
applications to random graphs. In particular, our result implies a number of
recent probabilistic versions, due to Conlon, Gowers, and Schacht, of classical
extremal combinatorial theorems. We also discuss several further applications.


title:
Dividing Line between Quantum and Classical Trajectories: Bohmian Time
  Constant

abstract:
  This work proposes an answer to a challenge posed by Bell on the lack of
clarity in regards to the line between the quantum and classical regimes in a
measurement problem. To this end, a generalized logarithmic nonlinear
Schr\"odinger equation is proposed to describe the time evolution of a quantum
dissipative system under continuous measurement. Within the Bohmian mechanics
framework, a solution to this equation reveals a novel result: it displays a
time constant which should represent the dividing line between the quantum and
classical trajectories. It is shown that continuous measurements and damping
not only disturb the particle but compel the system to converge in time to a
Newtonian regime. While the width of the wave packet may reach a stationary
regime, its quantum trajectories converge exponentially in time to classical
trajectories. In particular, it is shown that damping tends to suppress further
quantum effects on a time scale shorter than the relaxation time of the system.
If the initial wave packet width is taken to be equal to 2.8 10^{-15} m (the
approximate size of an electron), the Bohmian time constant is found to have an
upper limit, i. e., ${\tau_{B\max}} = {10^{- 26}}s$.


title:
Giant dipole resonance in $^{88}$Mo from phonon damping model's strength
  functions averaged over temperature and angular momentum distributions

abstract:
  The line shapes of giant dipole resonance (GDR) in the decay of the compound
nucleus $^{88}$Mo, which is formed after the fusion-evaporation reaction
$^{48}$Ti + $^{40}$Ca at various excitation energies $E^{*}$ from 58 to 308
MeV, are generated by averaging the GDR strength functions predicted within the
phonon damping model (PDM) using the empirical probabilities for temperature
and angular momentum. The average strength functions are compared with the PDM
strength functions calculated at the mean temperature and mean angular
momentum, which are obtained by averaging the values of temperature and angular
momentum using the same temperature and angular-momentum probability
distributions, respectively. It is seen that these two ways of generating the
GDR linear line shape yield very similar results. It is also shown that the GDR
width approaches a saturation at angular momentum $J\geq$ 50$\hbar$ at $T=$ 4
MeV and at $J\geq$ 70$\hbar$ at any $T$.


title: Three-box paradox and "Cheshire cat grin": the case of spin-1 atoms

abstract:
  We propose in this work a definite theoretical implementation of the
three-box paradox - a scheme in which a single quantum particle appears to be
present with certainty in two separate boxes - with spin-1 atoms. We further
show how our setup can give rise to a "Cheshire cat grin" type of situation, in
which an atom can apparently be found with certainty in one of the boxes while
one of its properties (the angular momentum projection along a specifically
chosen axis) appears to be in a different box. The significance of our findings
are discussed relative to the status of the properties of a system obtained
from weak measurements.


title: Unnormalized differences between zeros of L-functions

abstract:
  We study a subtle inequity in the distribution of unnormalized differences
between imaginary parts of zeros of the Riemann zeta function. We establish a
precise measure which explains the phenomenon, that the location of each
Riemann zero is encoded in the distribution of large Riemann zeros. We also
extend these results to zeros of more general L-functions. In particular, we
show how the rank of an elliptic curve over Q is encoded in the sequences of
zeros of other L-functions, not only the one associated to the curve.


title:
A sharp integral rearrangement inequality for the dyadic maximal
  operator and applications

abstract:
  We prove a sharp integral inequality for the dyadic maximal operator and give
as an application another proof for the computation of its Bellman function of
three variables.


title:
Extremal sequences for the Bellman function of the dyadic maximal
  operator and applications to the Hardy operator

abstract:
  We prove that the extremal sequences for the Bellman function of the dyadic
maximal operator behave approximately as eigenfunctions of this operator for a
specific eigenvalue. We use this result to prove the analogous one with respect
to the Hardy operator.


title: Demazure modules, Fusion products and Q--systems

abstract:
  In this paper, we introduce a family of indecomposable finite--dimensional
graded modules for the current algebra associated to a simple Lie algebra.
These modules are indexed by a tuple of partitions one for each positive root
of the simple Lie algebra. We assume that the partitions satisfy a natural
compatibility condition. In the case when the partitions are all rectangular,
for instance, we prove that these are precisely the Demazure modules which are
stable under the action of the simple Lie algebra. As a consequence we see that
the defining relations of these Demazure modules can be greatly simplified. We
use this simplified presentation to relate our results to the fusion products
(defined by Feigin and Loktev) of representations of the current algebra. We
prove that the Q--system can be actually thought of as a canonical short exact
of the fusion products of representations associated to certain special
partitions. Finally, in the last section we deal with the case of sl(2) and
prove that the modules we define are just fusion products of irreducible
representations of the associated current algebra. We also give monomial bases
for these modules.


title: Corrupted Sensing: Novel Guarantees for Separating Structured Signals

abstract:
  We study the problem of corrupted sensing, a generalization of compressed
sensing in which one aims to recover a signal from a collection of corrupted or
unreliable measurements. While an arbitrary signal cannot be recovered in the
face of arbitrary corruption, tractable recovery is possible when both signal
and corruption are suitably structured. We quantify the relationship between
signal recovery and two geometric measures of structure, the Gaussian
complexity of a tangent cone and the Gaussian distance to a subdifferential. We
take a convex programming approach to disentangling signal and corruption,
analyzing both penalized programs that trade off between signal and corruption
complexity, and constrained programs that bound the complexity of signal or
corruption when prior information is available. In each case, we provide
conditions for exact signal recovery from structured corruption and stable
signal recovery from structured corruption with added unstructured noise. Our
simulations demonstrate close agreement between our theoretical recovery bounds
and the sharp phase transitions observed in practice. In addition, we provide
new interpretable bounds for the Gaussian complexity of sparse vectors,
block-sparse vectors, and low-rank matrices, which lead to sharper guarantees
of recovery when combined with our results and those in the literature.


title:
Distinctive character of electronic and vibrational coherences in
  disordered molecular aggregates

abstract:
  Coherent dynamics of coupled molecules are effectively characterized by the
two-dimensional (2D) electronic coherent spectroscopy. Depending on the
coupling between electronic and vibrational states, oscillating signals of
purely electronic, purely vibrational or mixed origin can be observed. Even in
the "mixed" molecular systems two types of coherent beats having either
electronic or vibrational character can be distinguished by analyzing
oscillation Fourier maps, constructed from time-resolved 2D spectra. The
amplitude of the beatings with the electronic character is heavily affected by
the energetic disorder and consequently electronic coherences are quickly
dephased. Beatings with the vibrational character depend weakly on the
disorder, assuring their long-time survival. We show that detailed modeling of
2D spectroscopy signals of molecular aggregates providesdirect information on
the origin of the coherent beatings.


title: Quantum simulations of localization effects with dipolar interactions

abstract:
  Quantum information processing often uses systems with dipolar interactions.
We use a nuclear spin-based quantum simulator, to study the spreading of
information in such a dipolar-coupled system and how perturbations to the
dipolar couplings limit the spreading, leading to localization. In [Phys. Rev.
Lett. 104, 230403 (2010)], we found that the system reaches a dynamic
equilibrium size, which decreases with the square of the perturbation strength.
Here, we study the impact of a disordered Hamiltonian with dipolar 1/r^3
interactions. We show that the expansion of the coherence length of the cluster
size of the spins becomes frozen in the presence of large disorder, reminiscent
of Anderson localization of non-interacting waves in a disordered potential.

categories: quant-ph cond-mat.dis-nn cond-mat.mes-hall cond-mat.quant-gas


title:
Charging of graphene by magnetic field and mechanical effect of magnetic
  oscillations

abstract:
  We discuss the fact that quantum capacitance of graphene-based devices leads
to variation of it's charge density under changes of external magnetic
field.The charge is conserved, but redistributes to substrate or other graphene
sheet. We derive exact analytic expression for charge redistribution in the
case of ideal graphene in strong magnetic field. When we account for impurities
and temperature, the effect decreases and the formulae reduce to standard
quantum capacitance expressions. The importance of quantum capacitance for
potential Casimir force experiments is emphasized and an application of atomic
force microscope technique for measurement of density of states is proposed.


title:
Wetting and interfacial adsorption in the Blume-Capel model on the
  square lattice

abstract:
  We study the Blume-Capel model on the square lattice. To allow for wetting
and interfacial adsorption, the spins on opposite boundaries are fixed in two
different states, "+1" and "-1", with reduced couplings at one of the
boundaries. Using mainly Monte Carlo techniques, of Metropolis and Wang-Landau
type, phase diagrams showing bulk and wetting transitions are determined. The
role of the non-boundary state, "0", adsorbed preferably at the interface
between "-1" and "+1" rich regions, is elucidated.


title:
Tensor force and shape evolution of Si isotopes in Skyrme-Hartree-Fock
  model

abstract:
  Much interest has been devoted to the shape evolution of neutron-rich Si
isotopes recently both experimentally and theoretically. We provide our study
of $^{28-42}$Si by Skyrme-Hartree-Fock model with BCS approximation for the
pairing channel. We use an empirical pairing parameter deduced from the
experimental binding energy data for each nuclei and each Skyrme
parametrization. The recent highlight of the deformation change from a prolate
shape of $^{38}$Si to an oblate shape of $^{42}$Si is confirmed in the present
model. We also emphasize the role of tensor force on deformations of
neutron-rich $^{30,32}$Si, and discuss its underlying physics.


title:
Revisiting the hot matter in the center of gamma-ray bursts and
  supernova

abstract:
  Hot matter with nucleons can be produced in the inner region of the
neutrino-dominated accretion flow in gamma-ray bursts or during the
proto-neutron star birth in successful supernova. The composition and equation
of state of the matter depend on the dynamic $\beta$ equilibrium under various
neutrino opacities. The strong interaction between nucleons may also play an
important role. We plan to extend the previous studies by incorporating these
two aspects in our model. The modification of the $\beta$-equilibrium condition
from neutrino optically thin to thick has been modeled by an equilibrium factor
$\chi$ ranging between the neutrino-freely-escaping case and the
neutrino-trapped case. We employ the microscopic Brueckner-Hartree-Fock
approach extended to the finite temperature regime to study the interacting
nucleons. We show that the composition and chemical potentials of the hot
nuclear matter for different densities and temperatures at each stage of
$\beta$ equilibrium. We also compare our realistic equation of states with
those of the free gas model. We find the neutrino opacity and the strong
interaction between nucleons are important for the description and should be
taken into account in model calculations.


title:
Quasi-periodic events in crystal plasticity and the self-organized
  avalanche oscillator

abstract:
  When external stresses in a system - physical, social or virtual - are
relieved through impulsive events, it is natural to focus on the attributes of
these avalanches. However, during the quiescent periods in between, stresses
may be relieved through competing processes, such as slowly flowing water
between earthquakes or thermally activated dislocation flow between plastic
bursts. Such unassuming, smooth responses can have dramatic effects on the
avalanche properties. Here we report a thorough experimental investigation of
slowly compressed Ni microcrystals, covering three orders of magnitude in
nominal strain rate, that exhibits unconventional quasi-periodic avalanche
bursts and higher critical exponents as the strain rate is decreased. Our
analytic and computational study naturally extends dislocation avalanche
modeling to incorporate dislocation relaxations and reveals the emergence of
the self-organized avalanche oscillator, a novel critical state exhibiting
oscillatory approaches toward a depinning critical point. We demonstrate that
the predictions of our theory are faithfully exhibited in our experiments.

categories: cond-mat.stat-mech cond-mat.dis-nn cond-mat.soft nlin.AO nlin.CG


title: Learning Policies for Contextual Submodular Prediction

abstract:
  Many prediction domains, such as ad placement, recommendation, trajectory
prediction, and document summarization, require predicting a set or list of
options. Such lists are often evaluated using submodular reward functions that
measure both quality and diversity. We propose a simple, efficient, and
provably near-optimal approach to optimizing such prediction problems based on
no-regret learning. Our method leverages a surprising result from online
submodular optimization: a single no-regret online learner can compete with an
optimal sequence of predictions. Compared to previous work, which either learn
a sequence of classifiers or rely on stronger assumptions such as
realizability, we ensure both data-efficiency as well as performance guarantees
in the fully agnostic setting. Experiments validate the efficiency and
applicability of the approach on a wide range of problems including manipulator
trajectory optimization, news recommendation and document summarization.


title:
Partition functions for dense instances of combinatorial enumeration
  problems

abstract:
  Given a complete graph with positive weights on its edges, we define the
weight of a subset of edges as the product of weights of the edges in the
subset and consider sums (partition functions) of weights over subsets of
various kinds: cycle covers, closed walks, spanning trees. We show that if the
weights of the edges of the graph are within a constant factor, fixed in
advance, of each other then the bulk of the partition function is concentrated
on the subsets of a particularly simple structure: cycle covers with few
cycles, walks that visit every vertex only few times, and spanning trees with
small degree of every vertex. This allows us to construct a polynomial time
algorithm to separate graphs with many Hamiltonian cycles from graphs that are
sufficiently far from Hamiltonian.


title: Phase space analysis of interacting fermions

abstract:
  We propose the use of an orthogonal wave packet basis to analyze the
low-energy physics of interacting electron systems with short range order. We
give an introduction to wave packets and the related phase space representation
of fermion systems, and show that they lend themselves to an efficient
description of short range order. We illustrate the approach within an RG
calculation for the one-dimensional Hubbard chain.


title:
Polarimetry and the High-Energy Emission Mechanisms in Quasar Jets. The
  Case of PKS 1136-135

abstract:
  Since the discovery of kiloparsec-scale X-ray emission from quasar jets, the
physical processes responsible for their high-energy emission have been poorly
defined. A number of mechanisms are under active debate, including synchrotron
radiation, inverse-Comptonized CMB (IC/CMB) emission, and other Comptonization
processes. In a number of cases, the optical and X-ray emission of jet regions
are inked by a single spectral component, and in those, high- resolution
multi-band imaging and polarimetry can be combined to yield a powerful
diagnostic of jet emission processes. Here we report on deep imaging photometry
of the jet of PKS 1136$-$135 obtained with the {\it Hubble Space Telescope.} We
find that several knots are highly polarized in the optical, with fractional
polarization $\Pi>30%$. When combined with the broadband spectral shape
observed in these regions, this is very difficult to explain via IC/CMB models,
unless the scattering particles are at the lowest-energy tip of the electron
energy distribution, with Lorentz factor $\gamma \sim 1$, and the jet is also
very highly beamed ($\delta \geq 20$) and viewed within a few degrees of the
line of sight. We discuss both the IC/CMB and synchrotron interpretation of the
X-ray emission in the light of this new evidence, presenting new models of the
spectral energy distribution and also the matter content of this jet. The high
polarizations do not completely rule out the possibility of IC/CMB
optical-to-X-ray emission in this jet, but they do strongly disfavor the model.
We discuss the implications of this finding, and also the prospects for future
work.


title:
Protective Performance of Water-Based Epoxy Coating Containing ScCO2
  Synthesized Self-Doped Nanopolyaniline

abstract:
  In this research, corrosion properties of water-based epoxy coating is
improved by adding self-doped nano polyaniline (SPAni) synthesized using
supercritical carbon dioxide (ScCO2) medium. The modified ScCO2-synthesized
self-doped nano polyaniline (SPAni) using water-based polyamidoamine hardener
results formation of the water-based SPAni composite (Sc-WB). To obtain the
water-based polyaniline epoxy coating (SP-WBE), the Sc-WB was mixed with epoxy
resin in stoichiometric ratio. The formation of oxide layers and adhesion
properties of SP-WBE at corrosive medium was evaluated using scanning electron
microscopy (SEM) studies. The transmission electron microscopy (TEM) was used
to observe the distribution and particles size of nanopolyaniline in the final
dried film. The anti-corrosion performance of water-based epoxy coated sample
(blank coated sample) and SP-WBE coated sample was studied using salt spray
standard test according to ASTM B-117, electrochemical impedance spectroscopy
(EIS) and adhesion tests. The results indicate protective performance of
water-based epoxy coating is improved by adding self-doped polyaniline
synthesized at ScCO2 situation. The electrical resistance of the coatings
containing nanopolyaniline and the blank sample was 1.8778E+7 {\Omega}.cm2 and
2.512E+5 {\Omega}.cm2 after 1800 hours of immersion in 3.5 Wt% NaCl aqua
corrosive solutions.


title: On Creativity of Elementary Cellular Automata

abstract:
  We map cell-state transition rules of elementary cellular automata (ECA) onto
the cognitive control versus schizotypy spectrum phase space and interpret
cellular automaton behaviour in terms of creativity. To implement the mapping
we draw analogies between a degree of schizotypy and generative diversity of
ECA rules, and between cognitive control and robustness of ECA rules (expressed
via Derrida coefficient). We found that null and fixed point ECA rules lie in
the autistic domain and chaotic rules are 'schizophrenic'. There are no highly
articulated 'creative' ECA rules. Rules closest to 'creativity' domains are
two-cycle rules exhibiting wave-like patterns in the space-time evolution.


title: Cantor polynomials for semigroup sectors

abstract:
  A packing function on a set Omega in R^n is a one-to-one correspondence
between the set of lattice points in Omega and the set N_0 of nonnegative
integers. It is proved that if r and s are relatively prime positive integers
such that r divides s-1, then there exist two distinct quadratic packing
polynomials on the sector {(x,y) \in \R^2 : 0 \leq y \leq rx/s}. For the
rational numbers 1/s, these are the unique quadratic packing polynomials.
Moreover, quadratic quasi-polynomial packing functions are constructed for all
rational sectors.


title: Polynomial properties on large symmetric association schemes

abstract:
  In this paper we characterize "large" regular graphs using certain entries in
the projection matrices onto the eigenspaces of the graph. As a corollary of
this result, we show that "large" association schemes become $P$-polynomial
association schemes. Our results are summarized as follows. Let $G=(V,E)$ be a
connected $k$-regular graph with $d+1$ distinct eigenvalues
$k=\theta_0>\theta_1>\cdots>\theta_d$. Since the diameter of $G$ is at most
$d$, we have the Moore bound \[ |V| \leq M(k,d)=1+k \sum_{i=0}^{d-1}(k-1)^i. \]
Note that if $|V|> M(k,d-1)$ holds, the diameter of $G$ is equal to $d$. Let
$E_i$ be the orthogonal projection matrix onto the eigenspace corresponding to
$\theta_i$. Let $\partial(u,v)$ be the path distance of $u,v \in V$.
  Theorem. Assume $|V|> M(k,d-1)$ holds. Then for $x,y \in V$ with
$\partial(x,y)=d$, the $(x,y)$-entry of $E_i$ is equal to \[
-\frac{1}{|V|}\prod_{j=1,2,\ldots,d, j \ne i}
\frac{\theta_0-\theta_j}{\theta_i-\theta_j}. \] If a symmetric association
scheme $\mathfrak{X}=(X,\{R_i\}_{i=0}^d)$ has a relation $R_i$ such that the
graph $(X,R_i)$ satisfies the above condition, then $\mathfrak{X}$ is
$P$-polynomial. Moreover we show the "dual" version of this theorem for
spherical sets and $Q$-polynomial association schemes.


title: Finding Distinct Subpalindromes Online

abstract:
  We exhibit an online algorithm finding all distinct palindromes inside a
given string in time $\Theta(n\log|\Sigma|)$ over an ordered alphabet and in
time $\Theta(n|\Sigma|)$ over an unordered alphabet. Using a reduction from a
dictionary-like data structure, we prove the optimality of this algorithm in
the comparison-based computation model.


title: A reconstruction theorem for abelian categories of twisted sheaves

abstract:
  We use an idea of Rosenberg to prove a reconstruction theorem for abelian
categories of alpha-twisted quasi-coherent sheaves on quasi-compact and
quasi-separated schemes X when alpha is in the Brauer group of X. By applying
the work of To\"en on derived Azumaya algebras, we give a proof of
C\u{a}ld\u{a}raru's conjecture.


title: Magnetic fields of neutron stars

abstract:
  Neutron stars contain the strongest magnetic fields known in the Universe. In
this paper, I discuss briefly how these magnetic fields are inferred from
observations, as well as the evidence for their time-evolution. I show how
these extremely strong fields are actually weak in terms of their effects on
the stellar structure, as is also the case for magnetic stars on the upper main
sequence and magnetic white dwarfs, which have similar total magnetic fluxes. I
propose a scenario in which a stable hydromagnetic equilibrium (containing a
poloidal and a toroidal field component) is established soon after the birth of
the neutron star, aided by the strong compositional stratification of neutron
star matter, and this state is slowly eroded by non-ideal magnetohydrodynamic
processes such as beta decays and ambipolar diffusion in the core of the star
and Hall drift and breaking of the solid in its crust. Over sufficiently long
time scales, the fluid in the neutron star core will behave as if it were
barotropic, because, depending on temperature and magnetic field strength, beta
decays will keep adjusting the composition to the chemical equilibrium state,
or ambipolar diffusion will decouple the charged component from the neutrons.
Therefore, the still open question regarding stable hydromagnetic equilibria in
barotropic fluids will become relevant for the evolution, at least for
``magnetar'' fields, too strong to be stabilized by the solid crust.


title: Subset powers of directed cycles

abstract:
  For any directed graph G with vertex set V, the graph G^(d) is said to be a
subset power of G and is defined to have vertex set equal to the set of
d-element subsets of V; in G^(d), there is an edge from A to B if and only if
we can label the elements of A and B such that there is an edge in G between
each pair of corresponding elements. We determine the complete cycle structure
of C^(d), where C is a directed cycle of length l.


title:
Vertical shift and simultaneous Diophantine approximation on polynomial
  curves

abstract:
  The Hausdorff dimension of the set of simultaneously tau well approximable
points lying on a curve defined by a polynomial P(X)+alpha, where P(X) is a
polynomial with integer coefficients and alpha is in R, is studied when tau is
larger than the degree of P(X). This provides the first results related to the
computation of the Hausdorff dimension of the set of well approximable points
lying on a curve which is not defined by a polynomial with integer
coefficients. The proofs of the results also include the study of problems in
Diophantine approximation in the case where the numerators and the denominators
of the rational approximations are related by some congruential constraint.


title: Bandits with Knapsacks

abstract:
  Multi-armed bandit problems are the predominant theoretical model of
exploration-exploitation tradeoffs in learning, and they have countless
applications ranging from medical trials, to communication networks, to Web
search and advertising. In many of these application domains the learner may be
constrained by one or more supply (or budget) limits, in addition to the
customary limitation on the time horizon. The literature lacks a general model
encompassing these sorts of problems. We introduce such a model, called
"bandits with knapsacks", that combines aspects of stochastic integer
programming with online learning. A distinctive feature of our problem, in
comparison to the existing regret-minimization literature, is that the optimal
policy for a given latent distribution may significantly outperform the policy
that plays the optimal fixed arm. Consequently, achieving sublinear regret in
the bandits-with-knapsacks problem is significantly more challenging than in
conventional bandit problems.
  We present two algorithms whose reward is close to the information-theoretic
optimum: one is based on a novel "balanced exploration" paradigm, while the
other is a primal-dual algorithm that uses multiplicative updates. Further, we
prove that the regret achieved by both algorithms is optimal up to
polylogarithmic factors. We illustrate the generality of the problem by
presenting applications in a number of different domains including electronic
commerce, routing, and scheduling. As one example of a concrete application, we
consider the problem of dynamic posted pricing with limited supply and obtain
the first algorithm whose regret, with respect to the optimal dynamic policy,
is sublinear in the supply.


title:
Comparing Poiseuille with 1D Navier-Stokes Flow in Rigid and Distensible
  Tubes and Networks

abstract:
  A comparison is made between the Hagen-Poiseuille flow in rigid tubes and
networks on one side and the time-independent one-dimensional Navier-Stokes
flow in elastic tubes and networks on the other. Analytical relations, a
Poiseuille network flow model and two finite element Navier-Stokes
one-dimensional flow models have been developed and used in this investigation.
The comparison highlights the differences between Poiseuille and
one-dimensional Navier-Stokes flow models which may have been unjustifiably
treated as equivalent in some studies.


title:
Interaction Pressure Tensor for a class of Multicomponent Lattice
  Boltzmann models

abstract:
  We present a theory to obtain the pressure tensor for a class of non-ideal
multicomponent lattice Boltzmann models, thus extending the theory presented by
Shan (X. Shan, Phys. Rev. E 77, 066702 (2008)) for single component fluids. We
obtain the correct form of the pressure tensor directly on the lattice and the
resulting equilibrium properties are shown to agree very well with those
measured from numerical simulations. Results are compared with those of
alternative theories.


title: On Min-Cut Algorithms for Half-Duplex Relay Networks

abstract:
  Computing the cut-set bound in half-duplex relay networks is a challenging
optimization problem, since it requires finding the cut-set optimal half-duplex
schedule. This subproblem in general involves an exponential number of
variables, since the number of ways to assign each node to either transmitter
or receiver mode is exponential in the number of nodes. We present a general
technique that takes advantage of specific structures in the topology of a
given network and allows us to reduce the complexity of computing the
half-duplex schedule that maximizes the cut-set bound (with i.i.d. input
distribution). In certain classes of network topologies, our approach yields
polynomial time algorithms. We use simulations to show running time
improvements over alternative methods and compare the performance of various
half-duplex scheduling approaches in different SNR regimes.


title:
The Hodge filtration on complements of complex coordinate subspace
  arrangements and integral representations of holomorphic functions

abstract:
  We compute the Hodge filtration on cohomology groups of complements of
complex coordinate subspace arrangements. By means of this result we construct
integral representations of holomorphic functions such that kernels of these
representations have singularities on complex coordinate subspace arrangements.


title:
HERMES: towards an integrated toolbox to characterize functional and
  effective brain connectivity

abstract:
  The analysis of the interdependence between time series has become an
important field of research in the last years, mainly as a result of advances
in the characterization of dynamical systems from the signals they produce, the
introduction of concepts such as generalized and phase synchronization and the
application of information theory to time series analysis. In neurophysiology,
different analytical tools stemming from these concepts have added to the
'traditional' set of linear methods, which includes the cross-correlation and
the coherency function in the time and frequency domain, respectively, or more
elaborated tools such as Granger Causality. This increase in the number of
approaches to tackle the existence of functional (FC) or effective connectivity
(EC) between two (or among many) neural networks, along with the mathematical
complexity of the corresponding time series analysis tools, makes it desirable
to arrange them into a unified-easy-to-use software package. The goal is to
allow neuroscientists, neurophysiologists and researchers from related fields
to easily access and make use of these analysis methods from a single
integrated toolbox. Here we present HERMES (http://hermes.ctb.upm.es), a
toolbox for the Matlab environment (The Mathworks, Inc), which is designed for
the analysis functional and effective brain connectivity from
neurophysiological data such as multivariate EEG and/or MEG records. It
includes also visualization tools and statistical methods to address the
problem of multiple comparisons. We believe that this toolbox will be very
helpful to all the researchers working in the emerging field of brain
connectivity analysis.

categories: q-bio.NC cs.CE cs.MS physics.bio-ph physics.data-an


title: On ideals with the Rees property

abstract:
  A homogeneous ideal $I$ of a polynomial ring $S$ is said to have the Rees
property if, for any homogeneous ideal $J \subset S $ which contains $I$, the
number of generators of $J$ is smaller than or equal to that of $I$. A
homogeneous ideal $I \subset S$ is said to be $\mathfrak m$-full if $\mathfrak
mI:y=I$ for some $y \in \mathfrak m$, where $\mathfrak m$ is the graded maximal
ideal of $S$. It was proved by one of the authors that $\mathfrak m$-full
ideals have the Rees property and that the converse holds in a polynomial ring
with two variables. In this note, we give examples of ideals which have the
Rees property but are not $\mathfrak m$-full in a polynomial ring with more
than two variables. To prove this result, we also show that every Artinian
monomial almost complete intersection in three variables has the Sperner
property.


title:
Gamma-ray and X-ray Properties of Pulsar Wind Nebulae and Unidentified
  Galactic TeV Sources

abstract:
  We review properties of Galactic VHE sources detected at TeV energies. The
number of associations between the VHE sources and pulsars has grown in recent
years, making pulsar-wind nebulae the dominant population, although there is
still a substantial number of VHE sources which remain to be identified. Among
the latter there are several "dark" sources which do not have plausible
counterparts at any other wavelengths. In this review we compile and compare
the TeV and X-ray properties of pulsar wind nebulae (PWNe), PWN candidates, and
unidentified TeV sources.


title:
Practical Fine-grained Privilege Separation in Multithreaded
  Applications

abstract:
  An inherent security limitation with the classic multithreaded programming
model is that all the threads share the same address space and, therefore, are
implicitly assumed to be mutually trusted. This assumption, however, does not
take into consideration of many modern multithreaded applications that involve
multiple principals which do not fully trust each other. It remains challenging
to retrofit the classic multithreaded programming model so that the security
and privilege separation in multi-principal applications can be resolved.
  This paper proposes ARBITER, a run-time system and a set of security
primitives, aimed at fine-grained and data-centric privilege separation in
multithreaded applications. While enforcing effective isolation among
principals, ARBITER still allows flexible sharing and communication between
threads so that the multithreaded programming paradigm can be preserved. To
realize controlled sharing in a fine-grained manner, we created a novel
abstraction named ARBITER Secure Memory Segment (ASMS) and corresponding OS
support. Programmers express security policies by labeling data and principals
via ARBITER's API following a unified model. We ported a widely-used, in-memory
database application (memcached) to ARBITER system, changing only around 100
LOC. Experiments indicate that only an average runtime overhead of 5.6% is
induced to this security enhanced version of application.


title:
Electrically Modulated Thin Film Dynamics Controlling Bubble
  Manipulation in Microfluidic Confinement

abstract:
  Thin film dynamics and associated instability mechanisms have triggered a
wide range of scientific innovations, as attributed to their abilities of
creating fascinating patterns over small scales. Here, we demonstrate a new
thin film instability phenomenon governed by electro-mechanics and
hydrodynamics over interfacial scales in a narrow fluidic confinement. We first
bring out the essential physics of this instability mechanism, in consideration
with the fact that under the action of axial electrical field in a confined
microfluidic environment, perturbations may be induced on the interfaces of
thin corner films formed adjacent to the walls of a microchannel, leading to
the inception of ordered lateral structures. A critical electric field exists
beyond which these structures from the walls of the confinement intermingle to
evolve into localized gas pockets in the form of bubbles. These bubbles do not
remain static with further changes in electric field, but undergo a sequence of
elongation-deformation-breakup episode in a dynamically evolving manner. By
elucidating the complex interplay of electro-hydrodynmic forces and surface
tension, we offer further insights into a new paradigm of interfacial
instability mediated controlled microbubble manipulation for on-chip
applications, bearing far-ranging scientific and technological consequences in
executing designed fluidic operations in confined miniaturized environment.


title: Inverse Photoelectrochemical Cell

abstract:
  The splitting of water with sunlight using photoelectrochemical cell (PEC) to
produce hydrogen is a promising avenue for sustainable energy production. The
greatest virtue of PEC is that it uses sunlight as the only source to split
water, but its efficiencies are still quite low due to poor performances of the
available materials (such as SrTiO3). Consequently, another way of PEC research
has been developed. By simultaneously using sunlight and electricity as energy
source, PEC can get a larger current at a lower voltage, i.e., hydrogen can be
made under the voltage below 1.23V, the minimum voltage required by
electrolysis of water. But so far the efficiencies of the mainstream materials
(such as TiO2) remain low. Where is the future development direction of PEC?
Here we propose a new PEC model. Its operating principle is quite the opposite
of the aforesaid conventional PEC, that is, the previous
photoanode/photocathode is converted into the present photocathode/photoanode.
It can also obtain high current under low voltage, even near zero voltage in
extreme conditions. A basic single configuration and an improved n-p
configuration were designed. We reselected materials for photoelectrodes, and
confirmed its feasibility successfully. Two preliminary results were obtained
from two contrasts: whether compared with water electrolysis or conventional
PEC water splitting, the inverse PEC showed promising superiority.


title:
Temperature and Composition Dependence of Kinetics of Phase Separation
  in Solid Binary Mixtures

abstract:
  We present results for the kinetics of phase separation in solid binary
mixtures ($A_1+A_2$) from Monte Carlo simulations of the Ising model in two
dimensions. The simulation results are understood via appropriate application
of the finite-size scaling theory. At moderately high temperatures, for
symmetric $(50:50)$ compositions of $A_1$ and $A_2$ particles the average size
of the domains exhibit power-law growth with the exponent having the
Lifshitz-Slyozov value of 1/3 from very early time. However, our analysis shows
that for low enough temperatures, the growth exponent at early time is smaller
than the Lifshitz-Slyozov value. For composition dependence, we find that at
moderate temperature, even for extreme off-critical composition, curvature
dependent correction to the growth law is weak which is counterintuitive in
this case that gives rise to droplet morphology. This is however consistent
with the recent understanding on curvature dependence of surface tension.
Results from rather general studies on the finite-size effects with the
variations of temperature and composition have also been presented.


title:
Effects of Density Conservation and Hydrodynamics on Aging in
  Nonequilibrium Processes

abstract:
  Aging in kinetics of three different phase transitions, viz., magnetic,
binary solid and single component fluid, have been studied via Monte Carlo and
molecular dynamics simulations in three space dimensions with the objective of
identifying the effects of order-parameter conservation and hydrodynamics. We
observe that the relevant autocorrelations exhibit power-law decay in
ferromagnet and binary solid but with different exponents. At early time fluid
autocorrelation function nicely follows that of binary solid, the order
parameter being conserved for both of them, as opposed to a ferromagnet. At
late time the fluid data crosses over to an exponential decay which we identify
as a hydrodynamic effect and provide analytical justification for this
behavior.


title:
Interplay between out-of-plane magnetic plasmon and lattice resonance
  for modified resonance lineshape and near-field enhancement in double
  nanoparticles array

abstract:
  Two-dimensional double nanoparticles (DNPs) arrays are demonstrated
theoretically supporting the interaction of out-of-plane magnetic plasmons and
in-plane lattice resonances, which can be achieved by tuning the nanoparticle
height or the array period due to the height-dependent magnetic resonance and
the periodicity-dependent lattice resonance. The interplay of the two plasmon
modes can lead to a remarkable change in resonance lineshape and an improvement
of magnetic field enhancement. Simultaneous electric field and magnetic field
enhancements can be obtained in the gap regions between neighboring particles
at two resonance frequencies as the interplay occurs, which present open
cavities as electromagnetic field hot spots for potential applications on
detection and sensing. The results not only offer an attractive way to tune the
optical responses of plasmonic nanostructure, but also provide further insight
into the plasmons interactions in periodic nanostructure or metamaterials
comprising multiple elements.


title: Does the $8-N$ bonding rule break down in As$_2$Se$_3$ glass?

abstract:
  The local coordination numbers of As$_2$Se$_3$ glass were determined by a
combination of anomalous x-ray scattering experiments, reverse Monte Carlo
calculations, and {\it ab initio} molecular dynamics simulations. The
well-known `8-$N$ bonding rule' proposed by Mott breaks down around the As
atoms, exceeding the rule by 7--26%. An experimental prediction based on
mean-field theory agrees with the present experimental and theoretical results.
The fourfold coordinated As atoms likely form As-As wrong bond chains rather
than ethan-like configurations, which is identified as the origin for the
breakdown of the `8-$N$ bonding rule'.


title:
Classification of Spin-Nematic Squeezing in Spin-1 Collective Atomic
  Systems

abstract:
  In spin-1 collective atomic systems, the spin and nematic-tensor operators
constitute the su(3) Lie algebra whose su(2) subalgebras are shown to give two
distinct classes of squeezing which are unitarily equivalent to spin squeezing
and spin-nematic squeezing. We explicitly construct a unitary operator that
generates an arbitrary squeezed spin-nematic state from an arbitrary Fock
state. In particular, we demonstrate that squeezed spin states can be generated
from a polar state and that squeezed spin-nematic sates can be generated from a
fully spin-polarized state.


title: Strategic Planning for Network Data Analysis

abstract:
  As network traffic monitoring software for cybersecurity, malware detection,
and other critical tasks becomes increasingly automated, the rate of alerts and
supporting data gathered, as well as the complexity of the underlying model,
regularly exceed human processing capabilities. Many of these applications
require complex models and constituent rules in order to come up with decisions
that influence the operation of entire systems. In this paper, we motivate the
novel "strategic planning" problem -- one of gathering data from the world and
applying the underlying model of the domain in order to come up with decisions
that will monitor the system in an automated manner. We describe our use of
automated planning methods to this problem, including the technique that we
used to solve it in a manner that would scale to the demands of a real-time,
real world scenario. We then present a PDDL model of one such application
scenario related to network administration and monitoring, followed by a
description of a novel integrated system that was built to accept generated
plans and to continue the execution process. Finally, we present evaluations of
two different automated planners and their different capabilities with our
integrated system, both on a six-month window of network data, and using a
simulator.


title:
Grid diagrams and Manolescu's unoriented skein exact triangle for knot
  Floer homology

abstract:
  We re-derive Manolescu's unoriented skein exact triangle for knot Floer
homology over F_2 combinatorially using grid diagrams, and extend it to the
case with Z coefficients by sign refinements. Iteration of the triangle gives a
cube of resolutions that converges to the knot Floer homology of an oriented
link. Finally, we re-establish the homological sigma-thinness of
quasi-alternating links.


title:
Nonequilibrium transport of helical Luttinger liquids through a quantum
  dot

abstract:
  We study a steady state non-equilibrium transport between two interacting
helical edge states of a two dimensional topological insulator, described by
helical Luttinger liquids, through a quantum dot. For non-interacting dot the
current is obtained analytically by including the self-energy correction to the
dot Green's function. For interacting dot we use equation of motion method to
study the influence of weak on-site Coulomb interaction on the transport. We
find the metal-to-insulator quantum phase transition for attractive or
repulsive interactions in the leads when the magnitude of the interaction
strength characterized by a charge sector Luttinger parameter $K$ goes beyond a
critical value. The critical Luttinger parameter $K_{cr}$ depends on the hoping
strength between dot and the leads as well as the energy level of the dot with
respect to the Fermi levels of the leads, ranging from weak interaction regime
for dot level off resonance to strong interaction regime for dot in resonance
with the equilibrium Fermi level. Nearby the transition various singular
behaviors of current noise, dot density of state, and the decoherence rate
(inverse of lifetime) of the dot are briefly discussed.


title: Superradiance from a Charged Dilaton Black Hole

abstract:
  We study the behavior of the wave function of charged Klein-Gordon field
around a charge dilaton black hole. The rate of spontaneous charge loss is
estimated for large black hole case.


title:
A Gaussian Process Emulator Approach for Rapid Contaminant
  Characterization with an Integrated Multizone-CFD Model

abstract:
  This paper explores a Gaussian process emulator based approach for rapid
Bayesian inference of contaminant source location and characteristics in an
indoor environment. In the pre-event detection stage, the proposed approach
represents transient contaminant fate and transport as a random function with
multivariate Gaussian process prior. Hyper-parameters of the Gaussian process
prior are inferred using a set of contaminant fate and transport simulation
runs obtained at predefined source locations and characteristics. This paper
uses an integrated multizone-CFD model to simulate contaminant fate and
transport. Mean of the Gaussian process, conditional on the inferred
hyper-parameters, is used as an computationally efficient statistical emulator
of the multizone-CFD simulator. In the post event-detection stage, the Bayesian
framework is used to infer the source location and characteristics using the
contaminant concentration data obtained through a sensor network. The Gaussian
process emulator of the contaminant fate and transport is used for Markov Chain
Monte Carlo sampling to efficiently explore the posterior distribution of
source location and characteristics. Efficacy of the proposed method is
demonstrated for a hypothetical contaminant release through multiple sources in
a single storey seven room building. The method is found to infer location and
characteristics of the multiple sources accurately. The posterior distribution
obtained using the proposed method is found to agree closely with the posterior
distribution obtained by directly coupling the multizone-CFD simulator with the
Markov Chain Monte Carlo sampling.


title: Counterexamples to the List Square Coloring Conjecture

abstract:
  The square $G^2$ of a graph $G$ is the graph defined on $V(G)$ such that two
vertices $u$ and $v$ are adjacent in $G^2$ if the distance between $u$ and $v$
in $G$ is at most 2. Let $\chi(H)$ and $\chi_l(H)$ be the chromatic number and
the list chromatic number of $H$, respectively. A graph $H$ is called {\em
chromatic-choosable} if $\chi_l (H) = \chi(H)$. It is an interesting problem to
find graphs that are chromatic-choosable. Kostochka and Woodall \cite{KW2001}
conjectured that $\chi_l(G^2) = \chi(G^2)$ for every graph $G$, which is called
List Square Coloring Conjecture. In this paper, we give infinitely many
counterexamples to the conjecture. Moreover, we show that the value
$\chi_l(G^2) - \chi(G^2)$ can be arbitrary large.


title: Improved bounds on the chromatic numbers of the square of Kneser graphs

abstract:
  The Kneser graph $K(n,k)$ is the graph whose vertices are the $k$-elements
subsets of an $n$-element set, with two vertices adjacent if the sets are
disjoint. The square $G^2$ of a graph $G$ is the graph defined on $V(G)$ such
that two vertices $u$ and $v$ are adjacent in $G^2$ if the distance between $u$
and $v$ in $G$ is at most 2. Determining the chromatic number of the square of
the Kneser graph $K(2k+1, k)$ is an interesting problem, but not much progress
has been made. Kim and Nakprasit \cite{2004KN} showed that $\chi(K^2(2k+1,k))
\leq 4k+2$, and Chen, Lih, and Wu \cite{2009CLW} showed that $\chi(K^2(2k+1,k))
\leq 3k+2$ for $k \geq 3$. In this paper, we give improved upper bounds on
$\chi(K^2(2k+1,k))$. We show that $\chi(K^2(2k+1,k)) \leq 2k+2$, if $ 2k +1 =
2^n -1$ for some positive integer $n$. Also we show that $\chi(K^2(2k+1,k))
\leq \frac{8}{3}k+\frac{20}{3}$ for every integer $k\ge 2$. In addition to
giving improved upper bounds, our proof is concise and can be easily understood
by readers while the proof in \cite{2009CLW} is very complicated. Moreover, we
show that $\chi(K^2(2k+r,k))=\Theta(k^r)$ for each integer $2 \leq r \leq k-2$.


title:
On a relation between certain character values of symmetric groups and
  its connection with creation operators of symmetric functions

abstract:
  In this paper, we derive a relation of new kind between certain character
values of symmetric groups in terms of so-called maya diagrams. We also
investigate a relation between our result and Bernstein's creation operators
for Schur functions, and consider analogous relations for projective characters
of symmetric groups through creation operators for Schur $Q$-functions. We also
consider analogous relations for characters of Brauer algebras and walled
Brauer algebras.


title:
Conception design of helium ion FFAG accelerator with induction
  accelerating cavity

abstract:
  In the recent decades of particle accelerator R&D area, fixed field
alternating gradient (FFAG) accelerator has become a highlight for some
advantages of its higher beam intensity and lower cost, although there are
still some technical challenges. In this paper, FFAG accelerator is adopted to
accelerate helium ion beam on the one hand for the study of helium
embrittlement on fusion reactor envelope material and on the other hand for
promoting the conception research and design of FFAG accelerator and exploring
the possibility of developing high power FFAG accelerators. The conventional
period focusing unit of helium ion FFAG accelerator and three-dimensional model
of the large aperture combinatorial magnet by OPERA-TOSCA are given. For low
energy and low revolution frequency, induction acceleration is proposed to
replace conventional radio frequency(RF) acceleration for helium ion FFAG
accelerator, which avoids the potential breakdown of acceleration field caused
by wake field and improves the acceleration repetition frequency to gain higher
beam intensity. The main parameters and three-dimensional model of induction
cavity are given. Two special constraint waveforms are proposed to refrain from
particle accelerating time slip({\Delta}T) caused by accelerating voltage drop
of flat top and energy deviation. The particle longitudinal motion in two
waveforms is simulated.


title: Shock jump relations for a dusty gas atmosphere

abstract:
  This paper presents generalized forms of jump relations for one dimensional
shock waves propagating in a dusty gas. The dusty gas is assumed to be a
mixture of a perfect gas and spherically small solid particles, in which solid
particle are continuously distributed. The generalized jump relations reduce to
the Rankine-Hugoniot conditions for shocks in an idea gas when the mass
fraction (concentration) of solid particles in the mixture becomes zero. The
jump relations for pressure, density, temperature, particle velocity, and
change-in-entropy across the shock front are derived in terms of upstream Mach
number. Finally, the useful forms of the shock jump relations for weak and
strong shocks, respectively, are obtained in terms of the initial volume
fraction of the solid particles. The computations have been performed for
various values of mass concentration of the solid particles and for the ratio
of density of solid particles to the constant initial density of gas. Tables
and graphs of numerical results are presented and discussed.


title:
Ground state solution for a Kirchhoff problem with exponential critical
  growth

abstract:
  We establish the existence of a positive ground state solution for a
Kirchhoff problem in $\mathbb{R}^2$ involving critical exponential growth, that
is, the nonlinearity behaves like $\exp(\alpha_{0}s^{2})$ as $|s| \to \infty$,
for some $\alpha_{0}>0$. In order to obtain our existence result we used
minimax techniques combined with the Trudinger-Moser inequality.


title: On the omnipresent background gamma radiation of the continuous spectrum

abstract:
  The background spectrum of a germanium detector, shielded from the radiations
arriving from the lower and open for the radiations arriving from the upper
hemisphere is studied, both in a ground level and in an underground laboratory.
It is established that the continuous portion of this background spectrum is
mostly due to the radiations that arrive from the upper hemisphere of the
continuous spectrum similar to the instrumental one. The intensity of this
radiation of an average energy of about 120 keV is estimated to about 8000
photons/m2s 2\pi srad in a ground level laboratory, and to about 5000
photons/m2s 2\pi srad at the depth of 25 m.w.e. Rough estimates of the dose
that it contributes to the skin are about 1.5 nSv/h and 1 nSv/h respectively.
Simulations by GEANT4 and CORSIKA demonstrate that this radiation is both of
cosmic and terrestrial origin, mixed in proportion that still has to be
determined.


title:
On symmetric powers of $\tau$-recurrent sequences and deformations of
  Eisenstein series

abstract:
  We prove the equality of several $\tau$-recurrent sequences, which were first
considered by Pellarin, and which have close connections to Drinfeld vectorial
modular forms. Our result has several consequences: an $A$-expansion for the
$l^\text{th}$ power ($1 \leq l \leq q$) of the deformation of the weight 2
Eisenstein series; relations between Drinfeld modular forms with
$A$-expansions; a new proof of relations between special values of Pellarin
$L$-series.


title:
Cold Dark Matter and Higgs Mass in the Constrained Minimal
  Supersymmetric Standard Model with Generalized Yukawa Quasi-Unification

abstract:
  The construction of specific supersymmetric grand unified models based on the
Pati-Salam gauge group and leading to a set of Yukawa quasi-unification
conditions which can allow an acceptable b-quark mass within the constrained
minimal supersymmetric standard model with mu>0 is briefly reviewed. Imposing
constraints from the cold dark matter abundance in the universe, B physics, and
the mass mh of the lighter neutral CP-even Higgs boson, we find that there is
an allowed parameter space with, approximately, 44<tanbeta<52,
-3<A0/M_{1/2}<0.1, 122<mh/GeV<127, and mass of the lightest sparticle in the
range (0.75-1.43) TeV. Such heavy lightest sparticle masses can become
consistent with the cold dark matter requirements on the lightest sparticle
relic density thanks to neutralino-stau coannihilations which are enhanced due
to stau-antistau coannihilation to down type fermions via a direct-channel
exchange of the heavier neutral CP-even Higgs boson. Restrictions on the model
parameters by the muon anomalous magnetic moment are also discussed.


title:
Kondo spin liquid in Kondo necklace model: Classical disordered phase
  versus symmetry-protected topological state

abstract:
  We study possible topological features of Kondo spin liquid phase in terms of
the one- and two-dimensional Kondo necklace models within the frame work of
quantum O(N) non-liner sigma model (NLSM). In the one-dimensional case, it is
found that the bulk properties of the Kodno spin liquid phase are similar to
the well-known Haldane phase at strong coupling fixed point. The difference
between them mainly comes from their boundaries due to the effect of the
topological term. In the two-dimensional case, the system can be mapped onto an
O(4)-like NLSM with some O(3) anisotropy. Interestingly, we find that if
hedgehog-like point defects are included together with the restoration of the
full O(4) symmetry, our model is identical to a kind of SU(2)
symmetry-protected topological (SPT) state. Additionally, if the system has the
O(5) symmetry instead, the effective NLSM with Wess-Zumino-Witten term is just
a description of the surface modes of a three-dimensional SPT state, though
such O(5) NLSM could not be a proper description of Kondo spin liquid phase due
to its gaplessness. We expect that the discussions might provide useful threads
to identify certain microscopic bilayer antiferromagnet models (and related
materials), which can support the desirable SPT states.


title:
Simple-minded systems, configurations and mutations for
  representation-finite self-injective algebras

abstract:
  Simple-minded systems of objects in a stable module category are defined by
common properties with the set of simple modules, whose images under stable
equivalences do form simple-minded systems. Over a representation-finite
self-injective algebra, it is shown that all simple-minded systems are images
of simple modules under stable equivalences of Morita type, and that all
simple-minded systems can be lifted to Nakayama-stable simple-minded
collections in the derived category. In particular, all simple-minded systems
can be obtained algorithmically using mutations.


title: Landau Levels of Scalar QED in Time-Dependent Magnetic Fields

abstract:
  The Landau levels of scalar QED undergo continuous transitions under a
homogeneous, time-dependent magnetic field. We analytically formulate the
Klein-Gordon equation for a charged spinless scalar as a Cauchy initial value
problem in the two-component first order formalism and then put forth a measure
that classifies the quantum motions into the adiabatic change, the nonadiabatic
change, and the sudden change. We find the exact quantum motion and calculate
the pair-production rate when the magnetic field suddenly changes as a step
function.


title:
Intermediate effective interactions and dynamical fermion mass
  generation of QCD

abstract:
  The functional renormalization group equation is expanded to a two-loop form.
This two-loop form equation involves one-loop effective action. An intermediate
effective action perspective is adopted toward the one-loop effective action.
That is to say, the intermediate effective action could not be of the same form
of the bare action and one can make an ansatz to it. Thus by focusing on
different high dimensional operators, effects of the chosen operators can be
investigated. QCD through intermediate fermion-4 interactions is investigated.
Of the 6 kinds of fermion-4 interactions generated by one-loop QCD, 4 kinds
generate fermion mass while the other 2 kinds degenerate it. The net effect is
fermion mass degeneration when dimensionless mass is large. Flow patterns on
the $\tilde{m}^2_{\text{phys.}}-\tilde{g}^2$ plane are drawn.


title: Collective strong coupling in multimode cavity QED

abstract:
  We study an atom-cavity system in which the cavity has several degenerate
transverse modes. Mode-resolved cavity transmission spectroscopy reveals
well-resolved atom-cavity resonances for several cavity modes, a signature of
collective strong coupling for the different modes. Furthermore, the experiment
shows that the cavity modes are coupled via the atomic ensemble contained in
the cavity. The experimental observations are supported by a detailed
theoretical analysis. The work paves the way to the use of interacting
degenerate modes in cavity-based quantum information processing, where qubits
corresponding to different cavity modes interact via an atom shared by the two
modes. Our results are also relevant to the experimental realization of quantum
spin glasses with ultracold atoms.


title: Tame ramification and group cohomology

abstract:
  We give an intrinsic parametrisation of the set of tamely ramified extensions
of a local field with finite residue field and bring to the fore the role
played by group cohomology. We show that two natural definitions of the
cohomology class of a tamely ramified finite galoisian extension coincide, and
can be recovered from the parameter. We also give an elementary proof of
Serre's mass formula in the tame case and in the simplest wild case, and we
classify tame galoisian extensions of degree the cube of a prime.


title: Accelerated Mini-Batch Stochastic Dual Coordinate Ascent

abstract:
  Stochastic dual coordinate ascent (SDCA) is an effective technique for
solving regularized loss minimization problems in machine learning. This paper
considers an extension of SDCA under the mini-batch setting that is often used
in practice. Our main contribution is to introduce an accelerated mini-batch
version of SDCA and prove a fast convergence rate for this method. We discuss
an implementation of our method over a parallel computing system, and compare
the results to both the vanilla stochastic dual coordinate ascent and to the
accelerated deterministic gradient descent method of
\cite{nesterov2007gradient}.


title:
Multiplicity Distributions of Shower Particles and Target Fragments in
  84^Kr_36 - Emulsion Interactions at 1 GeV per nucleon

abstract:
  The article focuses on the multiplicity distributions of shower particles and
target fragments for the interaction of 84^Kr_36 possessing kinetic energy of
~1 GeV per nucleon with NIKFI BR-2 Nuclear Emulsion target. The experimental
multiplicity distributions of shower particles, grey fragments, black
fragments, and heavily ionization fragments are well described by the
multi-component Erlang distribution of the multi-source thermal model. We
observed a linear correlation in multiplicities for the above mentioned
particles or fragments. The further experimental studies showed that with the
increase of target fragment multiplicity, a saturation phenomenon was observed
in shower particle multiplicity.


title: Quantitative Study of Geometrical Scaling in Charm Production at HERA

abstract:
  We apply the method of ratios to search for geometrical scaling in the charm
production in deep inelastic scattering. To this end we use recent combined
data from H1 and ZEUS experiments. Two forms of geometrical scaling are tested:
originally proposed scaling which results from Golec-Biernat-Wusthoff model and
scaling motivated by a dipole representation which takes into account charm
mass. It turns out that in both cases some residual scaling is present and
charm mass inclusion improves scaling quality.


title: On Borsuk's conjecture for two-distance sets

abstract:
  In this paper we answer Larman's question on Borsuk's conjecture for
two-distance sets. We find a two-distance set consisting of 416 points on the
unit sphere in the dimension 65 which cannot be partitioned into 83 parts of
smaller diameter. This also reduces the smallest dimension in which Borsuk's
conjecture is known to be false. Other examples of two-distance sets with large
Borsuk's numbers will be given.


title: Interaction of multi-armed spirals in bistable media

abstract:
  We study the interaction of both dense and sparse multi-armed spirals in
bistable media modeled by equations of FitzHugh-Nagumo type. Dense 1-armed
spiral is characterized by its fixed tip. For dense multi-armed spirals, when
the initial distance between tips is less than a critical value, the arms
collide, connect and disconnect continuously as the spirals rotate. The
continuous reconstruction between the front and the back drives the tips to
corotate along a rough circle and to meander zigzaggedly. The rotation
frequency of tip, the frequency of zigzagged displacement, the frequency of
spiral, the oscillation frequency of media, and the number of arms satisfy
certain relations as long as the control parameters of the model are fixed.
When the initial distance between tips is larger than the critical value, the
behaviors of individual arms within either dense or sparse multi-armed spirals
are identical to that of corresponding 1-armed spirals.


title: Tail Asymptotics of Deflated Risks

abstract:
  Random deflated risk models have been considered in recent literatures. In
this paper, we investigate second-order tail behavior of the deflated risk X=RS
under the assumptions of second-order regular variation on the survival
functions of the risk R and the deflator S. Our findings are applied to
approximation of Value at Risk, estimation of small tail probability under
random deflation and tail asymptotics of aggregated deflated risk


title:
Fluid limits of G/G/1+G queues under the non-preemptive
  earliest-deadline-first discipline

abstract:
  A single-server queuing model is considered with customers that have
deadlines. If a customer's deadline elapses before service is offered, the
customer abandons the system (customers do not abandon while being served).
When the server becomes available, it offers service to the customer having
earliest deadline among those that are in the queue. We obtain a fluid limit of
the queue length and abandonment processes and for the occupation measure of
deadlines, in the form of measure-valued processes. We characterize the limit
by means of a Skorohod problem in a time-varying domain, which has an explicit
solution. The fluid limits also describe a certain process called the frontier,
that is well known to play a key role in systems operating under this
scheduling policy.


title: Causal set d'Alembertians for various dimensions

abstract:
  We propose, for dimension d, a discrete Lorentz invariant operator on scalar
fields that approximates the Minkowski spacetime scalar d'Alembertian. For each
dimension, this gives rise to a scalar curvature estimator for causal sets, and
thence to a proposal for a causal set action.


title: Atoms in the p-localization of stable homotopy category

abstract:
  We study $p$-localizations, where $p$ is an odd prime, of the full
subcategories $S^n$ of stable homotopy category consisting of CW-complexes
having cells in $n$ successive dimensions. Using the technique of triangulated
categories and matrix problems we classify atoms (indecomposable objects) in
$S_p^n$ for $n\le 4(p-1)$ and show that for $n>4(p-1)$ such classification is
wild in the sense of the representation theory.


title:
Quantum mechanical uncertainties and exact transition amplitudes for
  time dependent quadratic Hamiltonian

abstract:
  In this work we present the simplest generic form of the propagator for the
time-dependent quadratic Hamiltonian. We manifest the simplicity of our method
by giving explicitly the propagators for a free particle in time-dependent
electric field, forced harmonic oscillator and the Paul trap. Exact transition
amplitudes and uncertainties are calculated analytically for the Paul trap and
harmonic oscillator. The results show that near the instability regions very
large quantum mechanical uncertainties are obtained as demonstrated in a
special figure. The method is also applied to calculating the trajectory of a
classical forced time-dependent harmonic oscillator.


title: On simply connected K-contact non-Sasakian manifolds

abstract:
  We solve the problem posed by Boyer and Galicki about the existence of
K-contact simply connected manifolds with no Sasakian structure. Although the
result lies in the framework of metric contact geometry, our methods come from
contact and symplectic geometry and are based on the method of fat bundles
developed by Sternberg, Weinstein and Lerman.


title: On the Performance Limits of Scalar Coding Over MISO Channels

abstract:
  The performance limits of scalar coding for multiple-input single-output
channels are revisited in this work. By employing randomized beamforming,
Narula et al. demonstrated that the loss of scalar coding is universally
bounded by ~ 2.51 dB (or 0.833 bits/symbol) for any number of antennas and
channel gains. In this work, by using randomized beamforming in conjunction
with space-time codes, it is shown that the bound can be tightened to ~ 1.1 dB
(or 0.39 bits/symbol).


title: Uniqueness Theorem of W-Constraints for Simple Singularities

abstract:
  In a recent paper [3], Bakalov and Milanov proved that the total descendant
potential of a simple singularity satisfies the W-constraints, which come from
the W-algebra of the lattice vertex algebra associated to the root lattice of
this singularity and a twisted module of this vertex algebra. In the present
paper, we prove that the solution of these W-constraints is unique up to a
constant factor, as conjectured by Bakalov and Milanov in their paper.


title:
Rheological properties of soft-glassy flows from hydro-kinetic
  simulations

abstract:
  Based on numerical simulations of a lattice kinetic model for soft-glassy
materials, we characterize the global rheology of a dense emulsion-like system,
under three representative load conditions: Couette flow, time-oscillating
Strain and Kolmogorov flow. It is found that in all cases the rheology is
described by a Herschel-Bulkley (HB) relation, $\sigma = {\sigma}_{Y} + A
S^{\beta}$, with the yield stress ${\sigma}_{Y}$ largely independent of the
loading scenario. A proper rescaling of the HB parameters permits to describe
heterogeneous flows with space-dependent stresses, based on the notion of
cooperativity, as recently proposed to characterize the degree of non-locality
of stress relaxation phenomena in soft-glassy materials.


title: A hidden analytic structure of the Rabi model

abstract:
  The Rabi model describes the simplest interaction between a cavity mode with
a frequency $\omega_c$ and a two-level system with a resonance frequency
$\omega_0$. It is shown here that the spectrum of the Rabi model coincides with
the support of the discrete Stieltjes integral measure in the orthogonality
relations of recently introduced orthogonal polynomials. The exactly solvable
limit of the Rabi model corresponding to $\Delta=\omega_0/(2\omega_c)=0$, which
describes a displaced harmonic oscillator, is characterized by the discrete
Charlier polynomials in normalized energy $\upepsilon$, which are orthogonal on
an equidistant lattice. A non-zero value of $\Delta$ leads to non-classical
discrete orthogonal polynomials $\phi_{k}(\upepsilon)$ and induces a
deformation of the underlying equidistant lattice. The results provide a basis
for a novel analytic method of solving the Rabi model. The number of ca. {\em
1350} calculable energy levels per parity subspace obtained in double precision
(cca 16 digits) by an elementary stepping algorithm is up to two orders of
magnitude higher than is possible to obtain by Braak's solution. Any first $n$
eigenvalues of the Rabi model arranged in increasing order can be determined as
zeros of $\phi_{N}(\upepsilon)$ of at least the degree $N=n+n_t$. The value of
$n_t>0$, which is slowly increasing with $n$, depends on the required
precision. For instance, $n_t\simeq 26$ for $n=1000$ and dimensionless
interaction constant $\kappa=0.2$, if double precision is required. Although we
can rigorously prove our results only for dimensionless interaction constant
$\kappa< 1$, numerics and exactly solvable example suggest that the main
conclusions remain to be valid also for $\kappa\ge 1$.

categories: quant-ph cond-mat.mes-hall math-ph math.MP


title: Hermite Polynomial Representation of the Spin States

abstract:
  The invertable map of spin state density operator onto quasiprobability
distribution of three continuous variables is constructed. The connection with
two-mode electromagnetic field oscillators is discussed. The inversion formula
for spin-density matrix is given in terms of Hermite polynomials. The
connection with the spin-tomographic representation is examined. The problem of
the magnetic moment rotation in the magnetic field is considered in the
suggested representation of spin states.


title: Plane wave holonomies in loop quantum gravity I: symmetries and gauges

abstract:
  This is the first of two papers which study the behavior of the SU(2)
holonomies of loop quantum gravity (LQG), when they are acted upon by a
unidirectional, plane gravity wave. Initially, the LQG flux-holonomy variables
are treated as classical, commuting functions rather than quantized operators,
in a limit where variation from vertex to vertex are small and fields are weak.
Despite the weakness of the fields, the field equations are not linear. Also,
the theory can be quantized, and the expectation values of the quantum
operators behave like their classical analogs. Exact LQG theories may be either
local or non-local. The present paper argues that a wide class of non-local
theories share non-local features which survive to the semiclassical limit, and
these non-local features are included in the classical limit studied here. An
appendix computes the surface term required when the propagation direction is
the real line rather than $\mathrm{S}_1$. Paper II introduces coherent states,
constructs a damped sine wave solution to the constraints, and solves for the
behavior of the holonomies in the presence of the wave.


title: A square from similar rectangles

abstract:
  In the present popular science paper we determine when a square can be
dissected into rectangles similar to a given rectangle. The approach to the
question is based on a physical interpretation using electrical networks. Only
secondary school background is assumed in the paper.


title: Plane wave holonomies in loop quantum gravity II: sine wave solution

abstract:
  This paper constructs an approximate sinusoidal wave packet solution to the
equations of loop quantum gravity (LQG). There is an SU(2) holonomy on each
edge of the LQG simplex, and the goal is to study the behavior of these
holonomies under the influence of a passing gravitational wave. The equations
are solved in a small sine approximation: holonomies are expanded in powers of
sines, and terms beyond $\sin^2$ are dropped; also, fields vary slowly from
vertex to vertex. The wave is unidirectional and linearly polarized. The
Hilbert space is spanned by a set of coherent states tailored to the symmetry
of the plane wave case. Fixing the spatial diffeomorphisms is equivalent to
fixing the spatial interval between vertices of the loop quantum gravity
lattice. This spacing can be chosen such that the eigenvalues of the triad
operators are large, as required in the small sine limit, even though the
holonomies are not large. Appendices compute the energy of the wave, estimate
the lifetime of the coherent state packet, discuss coarse-graining, and
determine the behavior of the spinors used in the U(N) SHO realization of LQG.


title: Extended deterministic mean-field games

abstract:
  In this paper, we consider mean-field games where the interaction of each
player with the mean-field takes into account not only the states of the
players but also their collective behavior, To do so, we develop a random
variable framework that is particularly convenient for these problems. We prove
an existence result for extended mean-field games and establish uniqueness
conditions. In the last section, we consider the Master Equation and discuss
properties of its solutions.


title: Discovery of the magnetic field in the pulsating B star beta Cephei

abstract:
  Although the star itself is not He enriched, the periodicity and the
variability in the UV wind lines of the pulsating B1 IV star beta Cep are
similar to what is observed in magnetic He-peculiar B stars, suggesting that
beta Cep is magnetic. We searched for a magnetic field using
spectropolarimetry. From UV spectroscopy, we analysed the wind variability and
investigated the correlation with the magnetic data. Using 130 time-resolved
circular polarisation spectra, obtained with the MuSiCoS spectropolarimeter at
the 2m TBL from 1998 until 2005, we applied the least-squares deconvolution
method on the Stokes V spectra and derived the longitudinal component of the
integrated magnetic field over the visible hemisphere of the star. We performed
a period analysis on the magnetic data and on EW measurements of UV wind lines
obtained over 17 years. We also analysed the short- and long-term radial
velocity variations, which are due to the pulsations and the 90-year binary
motion. beta Cep hosts a sinusoidally varying magnetic field with an amplitude
97(4) G and an average value -6(3) G. From the UV wind line variability, we
derive a period of 12.00075(11) days, which is the rotation period of the star,
and is compatible with the observed magnetic modulation. Phases of maximum and
minimum field match those of maximum emission in the UV wind lines, strongly
supporting an oblique magnetic-rotator model. We discuss the magnetic behaviour
as a function of pulsation behaviour and UV line variability. This paper
presents the analysis of the first confirmed detection of a dipolar magnetic
field in an upper main-sequence pulsating star. Maximum wind absorption
originates in the magnetic equatorial plane. Maximum emission occurs when the
magnetic north pole points to the Earth. Radial velocities agree with the ~90-y
orbit around its Be-star binary companion.


title: Spin Pumping and Inverse Spin Hall Effect in Germanium

abstract:
  We have measured the inverse spin Hall effect (ISHE) in \textit{n}-Ge at room
temperature. The spin current in germanium was generated by spin pumping from a
CoFeB/MgO magnetic tunnel junction in order to prevent the impedance mismatch
issue. A clear electromotive force was measured in Ge at the ferromagnetic
resonance of CoFeB. The same study was then carried out on several test
samples, in particular we have investigated the influence of the MgO tunnel
barrier and sample annealing on the ISHE signal. First, the reference CoFeB/MgO
bilayer grown on SiO$_{2}$ exhibits a clear electromotive force due to
anisotropic magnetoresistance and anomalous Hall effect which is dominated by
an asymmetric contribution with respect to the resonance field. We also found
that the MgO tunnel barrier is essential to observe ISHE in Ge and that sample
annealing systematically lead to an increase of the signal. We propose a
theoretical model based on the presence of localized states at the interface
between the MgO tunnel barrier and Ge to account for these observations.
Finally, all of our results are fully consistent with the observation of ISHE
in heavily doped $n$-Ge and we could estimate the spin Hall angle at room
temperature to be $\approx$0.001.


title: The lightest scalar meson in a simple approach

abstract:
  We study basic properties of scalar hadronic resonances within a quantum
field theoretical toy model. In particular, we focus on the spectral function,
the mass and the decay width of the resonance $f_{0}(500)$. In this work, this
meson is understood as a seed state in an effective Lagrangian which couples to
pions. With such a setup we use the position of the pole on the second Riemann
sheet in order to obtain its spectral function. We confirm that $f_{0}(500)$
cannot be described by an ordinary Breit--Wigner function, and that a more
complicated structure is needed.


title: Bound entanglement in the Jaynes-Cummings model

abstract:
  We study in detail entanglement properties of the Jaynes-Cummings model
assuming a two-level atom (qubit) interacting with the first $N$ levels of an
electromagnetic field mode (qudit) in a cavity. In the Jaynes-Cummings model,
the number operator is the conserved quantity that allows for the exact
diagonalization of the Hamiltonian and thus we study states that commute with
this conserved quantity and whose structure is preserved under the
Jaynes-Cummings dynamics. Contrary to the common belief, we show that there are
bound entangled states that satisfy the symmetries imposed by the conservation
of the number of excitations when $N>3$. Furthermore we show that \emph{the
Jaynes-Cummings interaction can be used to generate bound-entanglement} between
the atom and the mode.