title: Some implications of the $2$-fold Bailey lemma

abstract:
  The $2$-fold Bailey lemma is a special case of the $s$-fold Bailey lemma
introduced by Andrews in 2000. We examine this special case and its
applications to partitions and recently discovered $q$-series identities. Our
work provides a general comparison of the utility of the $2$-fold Bailey lemma
and the more widely applied $1$-fold Bailey lemma. We also offer a discussion
of the $spt_M(n)$ function and related identities.


title:
Microcanonical work and fluctuation relations for an open system: An
  exactly solvable model

abstract:
  We calculate the probability distribution of work for an exactly solvable
model of a system interacting with its environment. The system of interest is a
harmonic oscillator with a time dependent control parameter, the environment is
modeled by $N$ independent harmonic oscillators with arbitrary frequencies, and
the system-environment coupling is bilinear and not necessarily weak. The
initial conditions of the combined system and environment are sampled from a
microcanonical distribution and the system is driven out of equilibrium by
changing the control parameter according to a prescribed protocol. In the limit
of infinitely large environment, i.e. $N \rightarrow \infty$, we recover the
nonequilibrium work relation and Crooks's fluctuation relation. Moreover, the
microcanonical Crooks relation is verified for finite environments. Finally, we
show the equivalence of multi-time correlation functions of the system in the
infinite environment limit for canonical and microcanonical ensembles.


title:
Spectra of Discrete Schr\"odinger Operators with Primitive Invertible
  Substitution Potentials

abstract:
  We study the spectral properties of discrete Schr\"odinger operators with
potentials given by primitive invertible substitution sequences (or by Sturmian
sequences whose rotation angle has an eventually periodic continued fraction
expansion, a strictly larger class than primitive invertible substitution
sequences). It is known that operators from this family have spectra which are
Cantor sets of zero Lebesgue measure. We show that the Hausdorff dimension of
this set tends to $1$ as coupling constant $\lambda$ tends to $0$. Moreover, we
also show that at small coupling constant, all gaps allowed by the gap labeling
theorem are open and furthermore open linearly with respect to $\lambda$.
Additionally, we show that, in the small coupling regime, the density of states
measure for an operator in this family is exact dimensional. The dimension of
the density of states measure is strictly smaller than the Hausdorff dimension
of the spectrum and tends to $1$ as $\lambda$ tends to $0$.


title: A Dual-Beam Method-of-Images 3D Searchlight BSSRDF

abstract:
  We present a novel BSSRDF for rendering translucent materials. Angular
effects lacking in previous BSSRDF models are incorporated by using a dual-beam
formulation. We employ a Placzek's Lemma interpretation of the method of images
and discard diffusion theory. Instead, we derive a plane-parallel
transformation of the BSSRDF to form the associated BRDF and optimize the image
confiurations such that the BRDF is close to the known analytic solutions for
the associated albedo problem. This ensures reciprocity, accurate colors, and
provides an automatic level-of-detail transition for translucent objects that
appear at various distances in an image. Despite optimizing the subsurface
fluence in a plane-parallel setting, we find that this also leads to fairly
accurate fluence distributions throughout the volume in the original 3D
searchlight problem. Our method-of-images modifications can also improve the
accuracy of previous BSSRDFs.


title: Desingularisation de metriques d'Einstein. II

abstract:
  We calculate a wall crossing formula for 4-dimensional Poincare-Einstein
metrics, through a wall made of orbifold Poincare-Einstein metrics with A1
singularities. This is based on a formalism which enables to deal with higher
order terms of the Einstein equation in this setting. Some other consequences
are deduced.


title: On the nonholonomic Stubler model

abstract:
  We discuss two constructions of the Poisson bivectors based on the
Euler-Jacobi theorem for the nonholonomic Stubler model, which describes
rolling without sliding of a uniform ball on a cylindrical surface.


title:
Calculation of $K \to \pi\pi$ decay amplitudes with improved Wilson
  fermion

abstract:
  We present results of our trial calculation of the $K \to \pi\pi$ decay
amplitudes with the improved Wilson fermion action. Calculations are carried
out with $N_f=2+1$ gauge configurations generated with the Iwasaki gauge action
and non-perturbatively $O(a)$-improved Wilson fermion action at $a=0.091\,{\rm
fm}$, $m_\pi=280\,{\rm MeV}$ and $m_K=560\,{\rm MeV} (\sim 2 m_\pi)$ on a
$32^3\times 64$ ($La=2.9 {\rm fm}$) lattice.


title:
Validation of a Control Algorithm for Human-like Reaching Motion using
  7-DOF Arm and 19-DOF Hand-Arm Systems

abstract:
  This technical report gives an overview of our work on control algorithms
dealing with redundant robot systems for achieving human-like motion
characteristics. Previously, we developed a novel control law to exhibit
human-motion characteristics in redundant robot arm systems as well as
arm-trunk systems for reaching tasks [1], [2]. This newly developed method
nullifies the need for the computation of pseudo-inverse of Jacobian while the
formulation and optimization of any artificial performance index is not
necessary. The time-varying properties of the muscle stiffness and damping as
well as the low-pass filter characteristics of human muscles have been modeled
by the proposed control law to generate human-motion characteristics for
reaching motion like quasi-straight line trajectory of the end-effector and
symmetric bell shaped velocity profile. This report focuses on the experiments
performed using a 7-DOF redundant robot-arm system which proved the
effectiveness of this algorithm in imitating human-like motion characteristics.
In addition, we extended this algorithm to a 19-DOF Hand-Arm System for a
reach-to-grasp task. Simulations using the 19-DOF Hand-Arm System show the
effectiveness of the proposed scheme for effective human-like hand-arm
coordination in reach-to-grasp tasks for pinch and envelope grasps on objects
of different shapes such as a box, a cylinder, and a sphere.


title:
The abstract Cauchy problem for the non-stationary bulk queue M(t)|M[k,
  B]|1

abstract:
  We derived state probability equations describing the queue M(t)|M[k, B]|1
and formulated as an abstract Cauchy problem to investigate by means of the
semi-group theory of bounded linear operators in functional analysis. For the
abstract Cauchy problem of this queue, we determined the eigenfunctions of
maximal operator and showed some properties of the Dirichlet operator.


title: A concentration-collapse decomposition for $L^2$ flow singularities

abstract:
  We exhibit a concentration-collapse decomposition of singularities of fourth
order curvature flows, including the $L^2$ curvature flow and Calabi flow, in
dimensions $n \leq 4$. The proof requires the development of several new a
priori estimates. First, we develop a smoothing result for initial metrics with
small energy and a volume growth lower bound, in the vein of Perelman's
pseudolocality result. Next, we generalize our technique from prior work to
exhibit local smoothing estimates for the $L^2$ flow in the presence of a
curvature-related bound. A final key ingredient is a new local
$\epsilon$-regularity result for $L^2$-critical metrics with possibly
nonconstant scalar curvature. Applications of these results include new
compactness and diffeomorphism-finiteness theorems for smooth compact
four-manifolds satisfying the necessary and effectively minimal hypotheses of
$L^2$ curvature pinching and a volume noncollapsing condition.


title:
Mixed valency and site-preference chemistry for Cerium and its
  compounds: A predictive DFT study

abstract:
  Cerium and its technologically relevant compounds are examples of anomalous
mixed valency, originating from two competing oxidation states -- itinerant
Ce$^{3+}$ and localized Ce$^{4+}$. Under applied stress, anomalous transitions
are observed but not well understood. Here we treat mixed valency as an "alloy"
involving two valences with competing and numerous site-occupancy
configurations, and we use density functional theory with Hubbard U ($i.e.$,
DFT+U) to evaluate the effective valence and predict properties, including
controlling valence by pseudo-ternary alloying. For Ce and its compounds, such
as (Ce-La)$_2$(Fe-Co)$_{14}$B permanent magnets, we find a stable mixed-valent
$\alpha$-state near the spectroscopic value of $\nu_s=3.53$. Ce valency in
compounds depends on its steric volume and local chemistry; for La doping,
Ce-valency shifts towards $\gamma$-like Ce$^{3+}$, as expected from steric
volume; for Co doping, valency depends on local Ce-site chemistry and steric
volume. Our approach captures the key origins of anomalous valency and
site-preference chemistry in complex compounds.


title:
Optical Spectrum of MoS${}_2$: Many-body Effects and Diversity of
  Exciton States

abstract:
  We present first-principles calculations of the optical response of monolayer
molybdenum disulfide employing the GW-Bethe Salpeter equation (GW-BSE) approach
including self-energy, excitonic, and electron-phonon effects. We show that
monolayer MoS2 possesses a large and diverse number of strongly bound excitonic
states with novel k-space characteristics that were not previously seen
experimentally or theoretically. The absorption spectrum is shown to be
dominated by excitonic states with binding energy close to $1$~eV and by strong
electron-phonon broadening in the visible to ultra-violet range. Our results
explain recent experimental measurements and resolve inconsistencies between
previous GW-BSE calculations.


title:
Donor and Acceptor Levels in Semiconducting Transition Metal
  Dichalcogenides

abstract:
  Density functional theory calculations are used to show that it is possible
to dope semiconducting transition metal dichalcogenides (TMD) such as MoS$_2$
and WS$_2$ with electrons and/or holes either by chemical substitution or by
adsorption on the sulfur layer. Notably, the activation energies of Lithium and
Phosphorus, a shallow donor and a shallow acceptor, respectively, are smaller
than 0.1 eV. Substitutional halogens are also proposed as alternative donors
adequate for different temperature regimes. All dopants proposed result in very
little lattice relaxation and, hence, are expected to lead to minor scattering
of the charge carriers. Doped MoS$_2$ and WS$_2$ monolayers are extrinsic in a
much wider temperature range than 3D semiconductors, making them superior for
high temperature electronic and optoelectronic applications.


title:
Spin accumulation detection of FMR driven spin pumping in silicon-based
  metal-oxide-semiconductor heterostructures

abstract:
  The use of the spin Hall effect and its inverse to electrically detect and
manipulate dynamic spin currents generated via ferromagnetic resonance (FMR)
driven spin pumping has enabled the investigation of these dynamically injected
currents across a wide variety of ferromagnetic materials. However, while this
approach has proven to be an invaluable diagnostic for exploring the spin
pumping process it requires strong spin-orbit coupling, thus substantially
limiting the materials basis available for the detector/channel material
(primarily Pt, W and Ta). Here, we report FMR driven spin pumping into a weak
spin-orbit channel through the measurement of a spin accumulation voltage in a
Si-based metal-oxide-semiconductor (MOS) heterostructure. This alternate
experimental approach enables the investigation of dynamic spin pumping in a
broad class of materials with weak spin-orbit coupling and long spin lifetime
while providing additional information regarding the phase evolution of the
injected spin ensemble via Hanle-based measurements of the effective spin
lifetime.


title: Event-Driven Contrastive Divergence for Spiking Neuromorphic Systems

abstract:
  Restricted Boltzmann Machines (RBMs) and Deep Belief Networks have been
demonstrated to perform efficiently in a variety of applications, such as
dimensionality reduction, feature learning, and classification. Their
implementation on neuromorphic hardware platforms emulating large-scale
networks of spiking neurons can have significant advantages from the
perspectives of scalability, power dissipation and real-time interfacing with
the environment. However the traditional RBM architecture and the commonly used
training algorithm known as Contrastive Divergence (CD) are based on discrete
updates and exact arithmetics which do not directly map onto a dynamical neural
substrate. Here, we present an event-driven variation of CD to train a RBM
constructed with Integrate & Fire (I&F) neurons, that is constrained by the
limitations of existing and near future neuromorphic hardware platforms. Our
strategy is based on neural sampling, which allows us to synthesize a spiking
neural network that samples from a target Boltzmann distribution. The recurrent
activity of the network replaces the discrete steps of the CD algorithm, while
Spike Time Dependent Plasticity (STDP) carries out the weight updates in an
online, asynchronous fashion. We demonstrate our approach by training an RBM
composed of leaky I&F neurons with STDP synapses to learn a generative model of
the MNIST hand-written digit dataset, and by testing it in recognition,
generation and cue integration tasks. Our results contribute to a machine
learning-driven approach for synthesizing networks of spiking neurons capable
of carrying out practical, high-level functionality.


title:
Matrix product states for anyonic systems and efficient simulation of
  dynamics

abstract:
  Matrix product states (MPS) have proven to be a very successful tool to study
lattice systems with local degrees of freedom such as spins or bosons.
Topologically ordered systems can support anyonic particles which are labeled
by conserved topological charges and collectively carry non-local degrees of
freedom. In this paper we extend the formalism of MPS to lattice systems of
anyons. The anyonic MPS is constructed from tensors that explicitly conserve
topological charge. We describe how to adapt the time-evolving block decimation
(TEBD) algorithm to the anyonic MPS in order to simulate dynamics under a local
and charge-conserving Hamiltonian. To demonstrate the effectiveness of anyonic
TEBD algorithm, we used it to simulate (i) the ground state (using imaginary
time evolution) of an infinite 1D critical system of (a) Ising anyons and (b)
Fibonacci anyons both of which are well studied, and (ii) the real time
dynamics of an anyonic Hubbard-like model of a single Ising anyon hopping on a
ladder geometry with an anyonic flux threading each island of the ladder. Our
results pertaining to (ii) give insight into the transport properties of
anyons. The anyonic MPS formalism can be readily adapted to study systems with
conserved symmetry charges, as this is equivalent to a specialization of the
more general anyonic case.


title: Results on conventional and exotic charmonium at BaBar

abstract:
  The B factories provide a unique playground for studying the properties of
conventional and exotic charmonium states. We present recent results in initial
state radiation and two-photon fusion, obtained using the full data set
collected by the BaBar experiment. Amongst BaBar 's harvest presented in this
talk, the determination of the quantum numbers of the X(3915) resonance, a body
of concording evidence pointing to JPC = 1++ for the X(3872), and updates on
the family of the Y resonance to the full integrated luminosity.


title: Complex Generalized Killing Spinors on Riemannian Spin$^c$ manifolds

abstract:
  In this paper, we extend the study of generalized Killing spinors on
Riemannian Spin$^c$ manifolds started by Moroianu and Herzlich to complex
Killing functions. We prove that such spinor fields are always real Spin$^c$
Killing spinors or imaginary generalized Spin$^c$ Killing spinors, providing
that the dimension of the manifold is greater or equal to 4. Moreover, we
classify Riemannian Spin$^c$ manifolds carrying imaginary and imaginary
generalized Killing spinors.


title:
On evolution of Primary Cosmic Ray mass composition in the energy region
  $10^{14}-10^{16}$ eV

abstract:
  A new method of determining Primary Cosmic Ray mass composition is proposed.
The method is based on quasi-localization of the integral equation for the
Extensive Air Showers spectrum versus the total number of high energy muons
($E_\mu \geqslant 235$ GeV) and an expansion of the experimentally measured
spectrum in spectra of five group of primary nuclei. The cosmic ray mass
composition is established in the energy region $10^{14}-10^{16}$ eV. In the
region $10^{15}-10^{16}$ eV our analysis points to a lightening of the mass
composition from $p+\alpha \simeq 0.54,\ \langle \ln A \rangle \simeq 1.97$ to
$p+\alpha \simeq 0.69,\ \langle \ln A \rangle\simeq 1.56$.


title:
Transport semigroup associated to positive boundary conditions of unit
  norm: a Dyson-Phillips approach

abstract:
  We revisit our study of general transport operator with general force field
and general invariant measure by considering, in the $L^1$ setting, the linear
transport operator $\T_H$ associated to a linear and positive boundary operator
$H$ of unit norm. It is known that in this case an extension of $\T_H$
generates a substochastic (i.e. positive contraction) $C_0$-semigroup
$(V_H(t))_{t\geq 0}$. We show here that $(V_H(t))_{t\geq 0}$ is the smallest
substochastic $C_0$-semigroup with the above mentioned property and provides a
representation of $(V_H(t))_{t \geq 0}$ as the sum of an expansion series
similar to Dyson-Phillips series. We develop an honesty theory for such
boundary perturbations that allows to consider the honesty of trajectories on
subintervals $J \subseteq [0,\infty)$. New necessary and sufficient conditions
for a trajectory to be honest are given in terms of the aforementioned series
expansion.


title: Atmospheric escape by magnetically driven wind from gaseous planets

abstract:
  We calculate the mass loss driven by MHD waves from hot Jupiters by using MHD
simulations in one-dimensional flux tubes. If a gaseous planet has magnetic
field, MHD waves are excited by turbulence at the surface, dissipate at the
upper atmosphere, and drive gas outflows. Our calculation shows that mass loss
rates are comparable to the observed mass loss rates of hot Jupiters, therefore
it is suggested that gas flow driven by MHD waves can plays an important role
in the mass loss from gaseous planets. The mass loss rate varies dramatically
with radius and mass of a planet: a gaseous planet with a small mass but with
inflated radius produces very large mass loss rate. We also derive an
analytical expression for the dependence of mass loss rate on planet radius and
mass that is in good agreement with the numerical calculation. The mass loss
rate also depends on the amplitude of velocity dispersion at the surface of a
planet. Thus we expect to infer the condition of the surface and the internal
structure of a gaseous planet from future observations of mass loss rate from
various exoplanets.


title: Automorphisms of the Affine Line over Nonreduced Rings

abstract: We study automorphisms of the affine line over rings like ZZ/p^n.


title: Positivity and Lifts of the Frobenius

abstract:
  We show that a smooth scheme over a ring of Witt vectors cannot have a lift
of the Frobenius if it has positive Kodaira dimension.


title:
Remarks on the uniqueness for quasilinear elliptic equations with
  quadratic growth conditions

abstract:
  In this note we present some uniqueness and comparison results for a class of
problem of the form \begin{equation} \label{EE0} \begin{array}{c} - L u =
H(x,u,\nabla u)+ h(x), \quad u \in H^1_0(\Omega) \cap L^{\infty}(\Omega),
\end{array} \end{equation} where $\Omega \subset \R^N$, $N \geq 2$ is a bounded
domain, $L$ is a general elliptic second order linear operator with bounded
coefficients and $H$ is allowed to have a critical growth in the gradient. In
some cases our assumptions prove to be sharp.


title:
Predicting how nanoconfinement changes the relaxation time of a
  supercooled liquid

abstract:
  The properties of nanoconfined fluids can be strikingly different from those
of bulk liquids. A basic unanswered question is whether the equilibrium and
dynamic consequences of confinement are related to each other in a simple way.
We study this question by simulation of a liquid comprising asymmetric
dumbbell-shaped molecules, which can be deeply supercooled without
crystallizing. We find that the dimensionless structural relaxation times -
spanning six decades as a function of temperature, density, and degree of
confinement - collapse when plotted versus excess entropy. The data also
collapse when plotted versus excess isochoric heat capacity, a behaviour that
follows from the existence of isomorphs in the bulk and confined states.


title:
Effective wall-laws for the Stokes equations over curved rough
  boundaries

abstract:
  We derive effective wall-laws for Stokes systems with inhomogeneous boundary
conditions in three dimensional bounded domains with curved rough boundaries.
No-slip boundary condition is given on the locally periodic rough boundary
parts with characteristic roughness size $\epsilon$ and boundary data is
assumed to be supported in the nonoscillatory smooth boundary.
  Based on the analysis of a boundary layer cell problem depending on geometry
of the fictitious boundary and roughness shape, boundary layer approximations
are constructed using orthogonal tangential vectors and normal vector on the
fictitious boundary, which have $O(\epsilon^{3/2})$-order in $L^2$-norm and
$O(\epsilon)$-order in energy-norm. Then, a Navier wall-law with error
estimates of $O(\epsilon^{3/2})$-order in $L^2$-norm and $O(\epsilon)$-order in
$W^{1,1}$-norm is obtained, which is proved to be irrespective of the choice of
the orthogonal tangent vectors.


title: Strongly Coupled Diamond Spin Qubits by Molecular Nitrogen Implantation

abstract:
  Ionized nitrogen molecules ($^{15}$N$_{2}^+$) are used as efficient point
sources for creating NV$^-$ pairs in diamond with nanoscale spatial separation
and up to 55 kHz magnetic coupling strength. Co-implantation of $^{12}$C$^+$
increased the yield of pairs, and a $^{13}$C-depleted diamond allowed 0.65 ms
coherence times to be obtained. Further coupling to a third dark spin provided
a strongly coupled three spin register. These results mark an important step
towards realization of multi-qubit systems and scalable NV$^-$ quantum
registers.


title:
Structure, elastic and dynamical properties of KN$_3$ and RbN$_3$: A van
  der Waals density functional study

abstract:
  We report a detailed first principles study on the structural, elastic,
vibrational and thermodynamic properties of layered structure energetic alkali
metal azides KN$_3$ and RbN$_3$. All the calculations were carried out by means
of plane wave pseudopotential method with and without including van der Waals
interactions. The calculated ground state structural properties are improved to
a greater extent by the inclusion of dispersion corrections, implies that the
van der Waals interactions play a major role on the physical properties of
these systems. The elastic constants and the related bulk mechanical properties
for the tetragonal KN$_3$ and RbN$_3$ have been calculated using both the
methods and found that the compounds are mechanically stable systems. The
magnitude of the calculated elastic constants increases in the order RbN$_3$
$<$ KN$_3$ implying higher elastic stiffness for KN$_3$, the fact also
confirmed by the higher values of bulk, shear and Young's moduli of KN$_3$ than
RbN$_3$. Moreover, the calculated elastic constants follows the inequality
C$_{33}$ $<$ C$_{11}$ which indicates the presence of more number of
intermolecular interactions along a-axis over c-axis of the azide lattices. A
correlation has been proposed to relate the calculated elastic constants to the
decomposition phenomena for the metal azides. The experimentally reported
vibrational frequencies at the gamma point were exactly reproduced by the
present calculations. In addition, we also present the thermodynamic properties
such as heat capacity which compares well with the experiment.


title:
The Association of Polar Faculae with Polar Magnetic Patches Examined
  with Hinode Observations

abstract:
  The magnetic properties of the Sun's polar faculae are investigated with
spectropolarimetric observations of the north polar region obtained by the
Hinode satellite in 2007 September. Polar faculae are embedded in nearly all
magnetic patches with fluxes greater than $10^{18}$ Mx, while magnetic patches
without polar faculae dominate in the flux range below $10^{18}$ Mx. The
faculae are considerably smaller than their parent patches, and single magnetic
patches contain single or multiple faculae. The faculae in general have higher
intrinsic magnetic field strengths than the surrounding regions within their
parent patches. Less than 20% of the total magnetic flux contributed by the
large (${\ge}10^{18}$ Mx) concentrations, which are known to be modulated by
the solar cycle, is accounted for by the associated polar faculae.


title: Spanning Simplicial Ccomplexes of Uni-Cyclic Graphs

abstract:
  In this paper, we introduce the concept of spanning simplicial complexes
$\Delta_s(G)$ associated to a simple finite connected graph G. We give the
characterization of all spanning trees of the uni-cyclic graph $U_{n,m}$. In
particular, we give the formula for computing the Hilbert series and h-vector
of the Stanley-Riesner ring k[\Delta_s(U_{n,m})]. Finally, we prove that the
spanning simplicial complex $\Delta_s(U_{n,m})$ is shifted hence
$\Delta_s(U_{n,m})$ is shellable.


title:
Adiabatic approximation for three qubits ultrastrongly coupled to a
  harmonic oscillator

abstract:
  We study the system involving mutual interaction between three qubits and an
oscillator within the ultrastrong coupling regime. We apply adiabatic
approximation approach to explore two extreme regimes: (i) the oscillator's
frequency is far larger than each qubit's frequency and (ii) the qubit's
frequency is far larger than the oscillator's frequency, and analyze the
energy-level spectrum and the ground-state property of the qubit-oscillator
system under the conditions of various system parameters. For the energy-level
spectrum, we concentrate on studying the degeneracy in low energy levels. For
the ground state, we focus on its nonclassical properties that are necessary
for preparing the nonclassical states. We show that the minimum
qubit-oscillator coupling strength needed for generating the nonclassical
states of the Schr\"{o}dinger-cat type in the oscillator is just one half of
that in the Rabi model. We find that the qubit-qubit entanglement in the ground
state vanishes if the qubit-oscillator coupling strength is strong enough, for
which the entropy of three qubits keeps larger than one. We also observe the
phase-transition-like behavior in the regime where the qubit's frequency is far
larger than the oscillator's frequency.


title:
{\it Ab-initio} study of structural and vibrational properties of KN$_3$
  under pressure

abstract:
  Structural stability and vibrational properties of KN$_3$ have been studied
under pressure using the first principles calculations based on the density
functional theory (DFT) as well as with semi empirical dispersion correction to
the DFT to treat van der Waals interactions. The structural properties
calculated through the dispersion correction are in good agreement with the
experimental results when compared with the standard density functional theory.
The lattice mode and the azide ion bending mode frequencies are found to be
well reproduced by our calculations. As pressure increases, the E$_g$ mode gets
softened as observed in the experiment. Despite the softening of E$_g$ mode,
the enhancement of intramolecular interactions keeps the lattice stable.


title:
The asymptotic size of the largest component in random geometric graphs
  with some applications

abstract:
  For the size of the largest component in a supercritical random geometric
graph, this paper estimates its expectation which tends to a polynomial on a
rate of exponential decay, and sharpens its asymptotic result with a central
limit theory. Similar results can be obtained for the size of biggest open
cluster, and for the number of open clusters of percolation on a box, and so
on.


title:
Decay rates of Gaussian-type I-balls and Bose-enhancement effects in 3+1
  dimensions

abstract:
  I-balls/oscillons are long-lived spatially localized lumps of a scalar field
which may be formed after inflation. In the scalar field theory with monomial
potential nearly and shallower than quadratic, which is motivated by chaotic
inflationary models and supersymmetric theories, the scalar field configuration
of I-balls is approximately Gaussian. If the I-ball interacts with another
scalar field, the I-ball eventually decays into radiation. Recently, it was
pointed out that the decay rate of I-balls increases exponentially by the
effects of Bose enhancement under some conditions and a non-perturbative method
to compute the exponential growth rate has been derived. In this paper, we
apply the method to the Gaussian-type I-ball in 3+1 dimensions assuming
spherical symmetry, and calculate the partial decay rates into partial waves,
labelled by the angular momentum of daughter particles. We reveal the
conditions that the I-ball decays exponentially, which are found to depend on
the mass and angular momentum of daughter particles and also be affected by the
quantum uncertainty in the momentum of daughter particles.


title: ATLAS results on soft diffraction

abstract:
  The measurements of the total inelastic cross section and the differential
inelastic cross section as a function of rapidity gap are presented. The data
used for these studies were collected in $pp$ collisions at a center-of-mass
energy of 7 TeV with the ATLAS detector at the LHC in 2010.


title:
On the uniform bound of the index of reducibility of parameter ideals of
  a module whose polynomial type is at most one

abstract:
  Let $(R, \frak m)$ be a Noetherian local ring, $M$ a finitely generated
$R$-module. The aim of this paper is to prove a uniform formula for the index
of reducibility of paprameter ideals of $M$ provided the polynomial type of $M$
is at most one.


title: Nucleation and growth of HfO$_2$ layers on graphene by CVD

abstract:
  A seed layer-free growth of HfO$_2$ on commercially available CVD graphene
from various suppliers is investigated. It is revealed that the samples of
monolayer graphene transferred from Cu to SiO$_2$/Si substrates have different
coverage with bi- and multi-layer graphene islands. We find that the
distribution and number of such islands impact the nucleation and growth of
HfO$_2$ by CVD. In particular, we show that the edges and surface of densely
distributed bi-layer graphene islands provide good nucleation sites for
conformal CVD HfO$_2$ layers. Dielectric constant of 16 is extracted from
measurements on graphene- HfO$_2$-TiN capacitors.


title: Large Margin Distribution Machine

abstract:
  Support vector machine (SVM) has been one of the most popular learning
algorithms, with the central idea of maximizing the minimum margin, i.e., the
smallest distance from the instances to the classification boundary. Recent
theoretical results, however, disclosed that maximizing the minimum margin does
not necessarily lead to better generalization performances, and instead, the
margin distribution has been proven to be more crucial. In this paper, we
propose the Large margin Distribution Machine (LDM), which tries to achieve a
better generalization performance by optimizing the margin distribution. We
characterize the margin distribution by the first- and second-order statistics,
i.e., the margin mean and variance. The LDM is a general learning approach
which can be used in any place where SVM can be applied, and its superiority is
verified both theoretically and empirically in this paper.


title:
On the Electromagnetic Design of a Beta_g= 0.61, 650 MHz Superconducting
  Radiofrequency Cavity

abstract:
  We present the calculations for electromagnetic design of a Beta_g = 0.61,
multi-cell superconducting radiofrequency cavity for the Indian Spallation
Neutron Source (ISNS) project. Geometry of the mid-cells is optimized using a
step by step, one-dimensional optimization technique. This is followed by the
optimization of end-cells, which is done to achieve the required field
flatness, as well as to avoid trapping of higher order modes. Calculations of
the threshold beam current for the excitation of regenerative beam break up
instability excited by the dipole modes is also presented, which is followed by
wake field calculations and estimation of its effects. Specific aspects
relevant to design calculations for medium Beta_g cavities, compared to high
Beta_g cavities are highlighted in the paper. Finally, studies are performed
for the static as well as dynamic Lorentz Force Detuning (LFD), based on which
the stiffness design of the cavity is optimized.


title: Topological Order in an Entangled SU(2)$\otimes$XY Spin-Orbital Ring

abstract:
  We present rigorous topological order which emerges in a one-dimensional
spin-orbital model due to the ring topology. Although an exact solution of a
spin-orbital ring with SU(2) spin and XY orbital interactions separates spins
from orbitals by means of a unitary transformation, the spins are not
independent when the ring is closed, but form two half-rings carrying opposite
pseudomomenta. We show that an inverse transformation back to the physical
degrees of freedom entangles the spin half-rings with the orbitals once again.
This surprising correlation arises on changing the topology from an open to a
closed chain, which reduces the degeneracy of the ground-state manifold,
leaving in it only the states in which pseudomomenta compensate each other.


title:
Signature of superradiance from a nitrogen gas plasma channel produced
  by strong field ionization

abstract:
  Recently, Yao et al. demonstrated the creation of coherent emissions in
nitrogen gas with two-color (800 nm + 400 nm) ultrafast laser pulses [New J.
Phys. 15, 023046 (2013)]. Based on this two-color scheme, here we report on
systematic investigation of temporal characteristics of the coherent emission
at 391 nm by experimentally examining its evolution with the increase of the
plasma channel induced by the intense 800 nm femtosecond laser pulses at a
nitrogen gas pressure of ~25 mbar. We reveal unexpected temporal profiles of
the coherent emissions, which show significant superradiance signatures owing
to the quantum coherence via cooperation of an ensemble of excited N2+
molecules. Our findings shed more light on the mechanisms behind the laser-like
emissions induced by strong-field ionization of molecules.


title:
Combinatorial model for the ferroelectric domain-network formation in
  hexagonal manganites

abstract:
  As the result of the high-temperature improper ferroelectric transition
occurring in YMnO3 and other hexagonal manganites a striking domain pattern was
observed: an emergence of six domains of alternating polarization from one
point in a vortex-like pattern. We derive the formation and distribution of the
domain-vortex network from a combinatorial analysis based on order-parameter
symmetry and lattice geometry. The analysis leads to stable vortex-like
configurations of the six domain states in the basal plane perpendicular to the
polarization and to fragmented vortices in planes parallel to the polarization.
The predictions are debated in the light of existing experimental and
theoretical work on the vortex domain state. The relation of the
symmetry-determined geomet- rical defects to the topological defects proposed
to describe the behavior of YMnO3 near the Curie temperature is discussed.


title: P wave bottomonium spectral functions in the QGP from lattice NRQCD

abstract:
  We present an overview of bottomonium spectral functions in the quark-gluon
plasma, obtained by the FASTSUM collaboration, using lattice QCD simulations
with two light quark flavours on anisotropic lattices. The bottom quark is
treated nonrelativistically. While we find that the S wave ground states
survive up to the highest temperature we consider, we have strong indications
that P wave states melt immediately above Tc.


title: High Redshift Investigation On The Dark Energy Equation of State

abstract:
  The understanding of the accelerated expansion of the Universe poses one of
the most fundamental questions in physics and cosmology today. Whether or not
the acceleration is driven by some form of dark energy, and in the absence of a
well-based theory to interpret the observations, many models have been proposed
to solve this problem, both in the context of General Relativity and
alternative theories of gravity. Actually, a further possibility to investigate
the nature of dark energy lies in measuring the dark energy equation of state
(EOS), w, and its time (or redshift) dependence at high accuracy. However,
since w(z) is not directly accessible to measurement, reconstruction methods
are needed to extract it reliably from observations. Here we investigate
different models of dark energy, described through several parametrizations of
the EOS. Our high-redshift analysis is based on the Union2 Type Ia Supernovae
(SNIa) data set, the Hubble diagram constructed from some Gamma Ray Bursts
(GRBs) luminosity distance indicators, and Gaussian priors on the distance from
the Baryon Acoustic Oscillations (BAO), and the Hubble constant h (these priors
have been included in order to help break the degeneracies among model
parameters). To perform our statistical analysis and to explore the probability
distributions of the EOS parameters we use the Markov Chain Monte Carlo Method
(MCMC). It turns out that the dark energy equation of state is evolving for all
the parametrizations that we considered. We finally compare our results with
the ones obtained by previous cosmographic analysis performed on the same
astronomical datasets, showing that the latter ones are sufficient to test and
compare the new parametrizations.


title: Electron swarm experiments in dense rare gases: a review

abstract:
  Swarm techniques have largely been used to investigate electron transport in
very dilute gases in order to shed light on the electron-atom (molecule)
scattering cross section and, hence, on the interaction potential. The
theoretical basis for the analysis of these experiments is classical Kinetic
Theory. However, electron transport in dense media, either in gaseous- or
condensed phase, is a physical phenomenon of fundamental and practical
interest. Dense rare gases are model systems for disordered media. They are
particularly well suited to investigate how the dynamics and energetics of
quasifree electrons change as the environment density is gradually increased. A
review on the electron swarm experiments in dense rare gases is presented here.


title:
High-Q silicon photonic crystal cavity for enhanced optical
  nonlinearities

abstract:
  We fabricate and experimentally characterize a $H0$ photonic crystal slab
nanocavity with a design optimized for maximal quality factor, $Q = 1.7$
million. The cavity, fabricated from a silicon slab, has a resonant mode at
$\lambda = 1.59 \mathrm{\mu m}$ and a measured $Q$-factor of $400,000$. It
displays nonlinear effects, including high-contrast optical bistability, at a
threshold power among the lowest ever reported for a silicon device. With a
theoretical modal volume as small as $V = 0.34(\lambda/n)^3$, this cavity ranks
among those with the highest $Q/V$ ratios ever demonstrated, while having a
small footprint suited for integration in photonic circuits.


title: Atomic Kapitza-Dirac effect with quadrupole transitions

abstract:
  Interactions between atoms and light fields are usually described in the
electric-dipole approximation. We show that electric-quadrupole terms are
important in the Kapitza-Dirac arrangement for light gratings on resonance with
a quadrupole atomic transition. We derive the diffraction patterns, which in
some cases are experimentally verifiable with the same techniques used with
dipole transitions.


title:
Non-equilibrium phase transition in relativistic nuclear collisions:
  Importance of the equation of state

abstract:
  Within the context of relativistic nuclear collisions aimed at exploring hot
and baryon-dense matter, we investigate how the general features of the
expansion dynamics, as well as a number of specific observables, depend on the
equation of state used in dynamical simulations of the non-equilibrium
confinement phase transition.


title:
Universal equation of state and pseudogap in the two-dimensional Fermi
  gas

abstract:
  We determine the thermodynamic properties and the spectral function for a
homogeneous two-dimensional Fermi gas in the normal state using the
Luttinger-Ward, or self-consistent T-matrix, approach. The density equation of
state deviates strongly from that of the ideal Fermi gas even for moderate
interactions, and our calculations suggest that temperature has a pronounced
effect on the pressure in the crossover from weak to strong coupling,
consistent with recent experiments. We also compute the superfluid transition
temperature for a finite system in the crossover region. There is a pronounced
pseudogap regime above the transition temperature: the spectral function shows
a Bogoliubov-like dispersion with back-bending, and the density of states is
significantly suppressed near the chemical potential. The contact density at
low temperatures increases with interaction and compares well with both
experiment and zero-temperature Monte Carlo results.


title: Explorations of the viability of ARM and Xeon Phi for physics processing

abstract:
  We report on our investigations into the viability of the ARM processor and
the Intel Xeon Phi co-processor for scientific computing. We describe our
experience porting software to these processors and running benchmarks using
real physics applications to explore the potential of these processors for
production physics processing.


title:
Polarization dependent, surface plasmon induced photoconductance in gold
  nanorod arrays

abstract:
  We report on the photoconductance in two-dimensional arrays of gold nanorods
which is strongly enhanced at the frequency of the longitudinal surface plasmon
of the nanorods. The arrays are formed by a combination of droplet deposition
and stamping of gold nanorod solutions on SiO2 substrates. We find that the
plasmon induced photoconductance is sensitive to the linear polarization of the
exciting photons. We interpret the occurrence of the photoconductance as a
bolometric enhancement of the arrays' conductance upon excitation of the
longitudinal surface plasmon resonance of the nanorods.


title:
Studying the metallicity gradient in Virgo Ellipticals with E-ELT
  photometry of resolved stars

abstract:
  The next generation of large aperture ground based telescopes will offer the
opportunity to perform accurate stellar photometry in very crowded fields. This
future capability will allow one to study in detail the stellar population in
distant galaxies. In this paper we explore the effect of photometric errors on
the stellar metallicity distribution derived from the color distribution of the
Red Giant Branch stars in the central regions of galaxies at the distance of
the Virgo cluster. We focus on the analysis of the Color-Magnitude Diagrams at
different radii in a typical giant Elliptical galaxy obtained from synthetic
data constructed to exemplify observations of the European Extremely Large
Telescope. The simulations adopt the specifications of the first light high
resolution imager MICADO and the expected performance of the Multi-Conjugate
Adaptive Optics Module MAORY. We find that the foreseen photometric accuracy
allows us to recover the shape of the metallicity distribution with a
resolution $\lesssim 0.4$ dex in the inner regions ($\mu_{\rm B}$ = 20.5 mag
arcsec$^{-2}$) and $\simeq 0.2$ dex in regions with $\mu_{\rm B}$ = 21.6 mag
arcsec$^{-2}$, that corresponds to approximately half of the effective radius
for a typical giant elliptical in Virgo. At the effective radius ($\mu_{\rm B}
\simeq 23$ mag arcsec$^{-2}$), the metallicity distribution is recovered with a
resolution of $\simeq 0.1$ dex. It will thus be possible to study in detail the
metallicity gradient of the stellar population over (almost) the whole
extension of galaxies in Virgo. We also evaluate the impact of moderate
degradations of the Point Spread Function from the assumed optimal conditions
and find similar results, showing that this science case is robust.


title:
Detectability of Torsion Gravity via Galaxy Clustering and Cosmic Shear
  Measurements

abstract:
  Alterations of the gravity Lagrangian introduced in modified torsion gravity
theories---also referred to as $f(T)$ gravity---allows for an accelerated
expansion in a matter dominated Universe. In this framework, the cosmic speed
up is driven by an effective `torsion fluid'. Besides the background evolution
of the Universe, structure formation is also modified because of a time
dependent effective gravitational constant. Here, we investigate the imprints
of $f(T)$ gravity on galaxy clustering and weak gravitational lensing to the
aim of understanding whether future galaxy surveys could constrain torsion
gravity and discriminate amongst it and standard general relativity.
Specifically, we compute Fisher matrix forecasts for two viable $f(T)$ models
to both infer the accuracy on the measurement of the model parameters and
evaluate the power that a combined clustering and shear analysis will have as a
tool for model selection. We find that with such a combination of probes it
will indeed be possible to tightly constrain $f(T)$ model parameters. Moreover,
the Occam's razor provided by the Bayes factor will allow us to confirm an
$f(T)$ power-law extension of the concordance $\Lambda{\rm CDM}$ model, were a
value larger than 0.02 of its power-law slope measured, whereas in $\Lambda{\rm
CDM}$ it is exactly 0.


title:
Electron-Phonon Coupling and the Metalization of Solid Helium at
  Terapascal Pressures

abstract:
  Solid He is studied in the pressure and temperature ranges 1-40 TPa and
0-10,000 K using first-principles methods. Anharmonic vibrational properties
are calculated within a self-consistent field framework, including the internal
and free energies, density-pressure relation, stress tensor, thermal expansion,
and the electron-phonon coupling renormalization of the electronic band gap. We
find that an accurate description of electron-phonon coupling requires us to
use a non-perturbative approach. The metalization pressure of 32.9 TPa at 0 K
is larger than found previously. The vibrational effects are large; for example
at P=30 TPa the band gap is increased by 2.8 eV by electron-phonon coupling and
a further 0.1 eV by thermal expansion compared to the static value. The
implications of the calculated metalization pressure for the cooling of white
dwarfs are discussed.


title:
Dynamic autotuning of adaptive fast multipole methods on hybrid
  multicore CPU & GPU systems

abstract:
  We discuss an implementation of adaptive fast multipole methods targeting
hybrid multicore CPU- and GPU-systems. From previous experiences with the
computational profile of our version of the fast multipole algorithm, suitable
parts are off-loaded to the GPU, while the remaining parts are threaded and
executed concurrently by the CPU. The parameters defining the algorithm affects
the performance and by measuring this effect we are able to dynamically balance
the algorithm towards optimal performance. Our setup uses the dynamic nature of
the computations and is therefore of general character.


title: A multiscale analysis of diffusions on rapidly varying surfaces

abstract:
  Lateral diffusion of molecules on surfaces plays a very important role in
various biological processes, including lipid transport across the cell
membrane, synaptic transmission and other phenomena such as exo- and
endocytosis, signal transduction, chemotaxis and cell growth. In many cases,
the surfaces can possess spatial inhomogeneities and/or be rapidly changing
shape. Using a generalisation of the model for a thermally excited Helfrich
elastic membrane, we consider the problem of lateral diffusion on quasi-planar
surfaces, possessing both spatial and temporal fluctuations. Using results from
homogenisation theory, we show that, under the assumption of scale separation
between the characteristic length and time scales of the membrane fluctuations
and the characteristic scale of the diffusing particle, the lateral diffusion
process can be well approximated by a Brownian motion on the plane with
constant diffusion tensor $D$ which depends in a highly nonlinear way on the
detailed properties of the surface. The effective diffusion tensor will depend
on the relative scales of the spatial and temporal fluctuations and, for
different scaling regimes, we prove the existence of a macroscopic limit in
each case.


title: Affine Grassmannians and Geometric Satake Equivalences

abstract:
  I extend the ramified geometric Satake equivalence of Zhu from tamely
ramified groups to include the case of general connected reductive groups. As a
prerequisite I prove basic results on the geometry of affine flag varieties.


title: Geant4 based simulations for novel neutron detector development

abstract:
  A Geant4-based Python/C++ simulation and coding framework, which has been
developed and used in order to aid the R&D efforts for thermal neutron
detectors at neutron scattering facilities, is described. Built upon
configurable geometry and generator modules, it integrates a general purpose
object oriented output file format with meta-data, developed in order to
facilitate a faster turn-around time when setting up and analysing simulations.
Also discussed are the extensions to Geant4 which have been implemented in
order to include the effects of low-energy phenomena such as Bragg diffraction
in the polycrystalline support materials of the detector. Finally, an example
application of the framework is briefly shown.

categories: physics.ins-det hep-ex nucl-ex physics.comp-ph


title:
NaNet:a low-latency NIC enabling GPU-based, real-time low level trigger
  systems

abstract:
  We implemented the NaNet FPGA-based PCI2 Gen2 GbE/APElink NIC, featuring
GPUDirect RDMA capabilities and UDP protocol management offloading. NaNet is
able to receive a UDP input data stream from its GbE interface and redirect it,
without any intermediate buffering or CPU intervention, to the memory of a
Fermi/Kepler GPU hosted on the same PCIe bus, provided that the two devices
share the same upstream root complex. Synthetic benchmarks for latency and
bandwidth are presented. We describe how NaNet can be employed in the prototype
of the GPU-based RICH low-level trigger processor of the NA62 CERN experiment,
to implement the data link between the TEL62 readout boards and the low level
trigger processor. Results for the throughput and latency of the integrated
system are presented and discussed.


title:
A surface-patterned chip as a strong source of ultra-cold atoms for
  quantum technologies

abstract:
  Laser cooled atoms are central to modern precision measurements. They are
also increasingly important as an enabling technology for experimental cavity
quantum electrodynamics, quantum information processing and matter wave
interferometry. Although significant progress has been made in miniaturising
atomic metrological devices, these are limited in accuracy by their use of hot
atomic ensembles and buffer gases. Advances have also been made in producing
portable apparatus that benefit from the advantages of atoms in the microKelvin
regime. However, simplifying atomic cooling and loading using microfabrication
technology has proved difficult. In this letter we address this problem,
realising an atom chip that enables the integration of laser cooling and
trapping into a compact apparatus. Our source delivers ten thousand times more
atoms than previous magneto-optical traps with microfabricated optics and, for
the first time, can reach sub-Doppler temperatures. Moreover, the same chip
design offers a simple way to form stable optical lattices. These features,
combined with the simplicity of fabrication and the ease of operation, make
these new traps a key advance in the development of cold-atom technology for
high-accuracy, portable measurement devices.


title: Measuring the entropy from shifted boundary conditions

abstract:
  We explore a new computational strategy for determining the equation of state
of the SU(3) Yang-Mills theory. By imposing shifted boundary conditions, the
entropy density is computed from the vacuum expectation value of the
off-diagonal components T_{0k} of the energy-momentum tensor. A step-scaling
function is introduced to span a wide range in temperature values. We present
preliminary numerical results for the entropy density and its step-scaling
function obtained at eight temperature values in the range T_c - 15 T_c. At
each temperature, discretization effects are removed by simulating the theory
at several lattice spacings and by extrapolating the results to the continuum
limit. Finite-size effects are always kept below the statistical errors. The
absence of ultraviolet power divergences and the remarkably small
discretization effects allow for a precise determination of the step-scaling
function in the explored temperature range. These findings establish this
strategy as a viable solution for an accurate determination of the equation of
state in a wide range of temperature values.


title:
Interference Alignment (IA) and Coordinated Multi-Point (CoMP) with
  IEEE802.11ac feedback compression: testbed results

abstract:
  We have implemented interference alignment (IA) and joint transmission
coordinated multipoint (CoMP) on a wireless testbed using the feedback
compression scheme of the new 802.11ac standard. The performance as a function
of the frequency domain granularity is assessed. Realistic throughput gains are
obtained by probing each spatial modulation stream with ten different coding
and modulation schemes. The gain of IA and CoMP over TDMA MIMO is found to be
26% and 71%, respectively under stationary conditions. In our dense indoor
office deployment, the frequency domain granularity of the feedback can be
reduced down to every 8th subcarrier (2.5MHz), without sacrificing performance.


title:
Fermi surface and electron dispersions of PbTe doped with resonant Tl
  impurity from KKR-CPA calculations

abstract:
  We present results of detailed study on the electron dispersions and Fermi
surface of lead telluride doped with $2\%$ of thallium, which is resonant
impurity in PbTe. Using the KKR--CPA method, Bloch spectral functions (BSFs),
which replace the dispersion relations in alloys, are calculated, and BSFs
intensity maps over the Brillouin zone (alloy Fermi surface cross-sections) are
presented. It is shown, that close to the valence band edge, Tl does not create
an isolated impurity band, but due to its resonant character, strongly disturbs
the host electronic bands, leading to disappearance of sharp and well defined
electronic energy bands. Consequences of this effect on the transport
properties are discussed and new qualitative explanation of the improvement in
thermoelectric properties of PbTe:Tl is suggested.


title:
Systematic properties of decelerating relativistic jets in
  low-luminosity radio galaxies

abstract:
  We model the kiloparsec-scale synchrotron emission from jets in 10
Fanaroff-Riley Class I radio galaxies for which we have sensitive,
high-resolution imaging and polarimetry from the Very Large Array. We assume
that the jets are intrinsically symmetrical, axisymmetric, decelerating,
relativistic outflows and we infer their inclination angles and the spatial
variations of their flow velocities, magnetic field structures and emissivities
using a common set of fitting functions. The inferred inclinations agree well
with independent indicators. The spreading rates increase rapidly, then
decrease, in a flaring region. The jets then recollimate to form conical outer
regions at distance r0 from the active galactic nucleus (AGN). The flaring
regions are homologous when scaled by r0. At ~0.1r0, the jets brighten abruptly
at the onset of a high-emissivity region and we find an outflow speed of ~0.8c,
with a uniform transverse profile. Jet deceleration first becomes detectable at
~0.2r0 and the outflow often becomes slower at its edges than it is on-axis.
Deceleration continues until ~0.6r0, after which the outflow speed is usually
constant. The dominant magnetic-field component is longitudinal close to the
AGN and toroidal after recollimation, but the field evolution is initially much
slower than predicted by flux-freezing. In the flaring region, acceleration of
ultrarelativistic particles is required to counterbalance the effects of
adiabatic losses and account for observed X-ray synchrotron emission, but the
brightness evolution of the outer jets is consistent with adiabatic losses
alone. We interpret our results as effects of the interaction between the jets
and their surroundings. (Slightly abridged).


title:
Pressure induced structural phase transition in solid oxidizer KClO$_3$:
  A first-principles study

abstract:
  High pressure behavior of potassium chlorate (KClO$_3$) has been investigated
from 0-10 GPa by means of first principles density functional theory (DFT)
calculations. The calculated ground state parameters, transition pressure and
phonon frequencies using semiempirical dispersion correction scheme are in
excellent agreement with experiment. It is found that KClO$_3$ undergoes a
pressure induced first order phase transition with an associated volume
collapse of 6.4$\%$ from monoclinic (\emph{P2$_1$/m}) $\rightarrow$
rhombohedral (\emph{R3m}) structure at 2.26 GPa, which is in good accord with
experimental observation. However, the transition pressure was found to
underestimate (0.11 GPa) and overestimate (3.57 GPa) using LDA and GGA
functionals, respectively. Mechanical stability of both the phases are
explained from the calculated single crystal elastic constants. In addition,
the zone center phonon frequencies have been calculated using density
functional perturbation theory at ambient as well as at high pressure and the
lattice modes are found to soften under pressure between 0.6 to 1.2 GPa. The
present study reveals that the observed structural phase transition leads to
changes in the decomposition mechanism of KClO$_3$ which corroborates with the
experimental results.


title: Andreev levels spectroscopy of topological three-terminal junctions

abstract:
  We calculate the differential conductance at a probe inserted in the weak
link of a topological Josephson junction, consisting of a semiconducting
nanowire deposited on top of two separated superconductors. Our aim is to
understand how the peculiar features in the spectrum of Andreev bound states,
arising due to the presence of Majorana bound states at the ends of the two
topological superconducting wires defining the junction, can be determined
through a measurement of the differential conductance. We find that when the
probe allows a single propagating mode, the differential conductance presents a
dip at zero voltage of zero conductance close to the position where the
spectrum exhibits the topologically protected crossing. This can be viewed as a
signature of the presence of Majorana states, which does not require fermion
parity conservation and is robust against parameters' changes, as well as
disorder. On the contrary, when the probe allows two or more propagating modes
the differential conductance resembles the spectrum of Andreev bound states.
This has been established making use of both numerical and analytical methods.


title: Resource Management for Device-to-Device Underlay Communication

abstract:
  Device-to-Device (D2D) communication is a technology component for LTE-A. The
existing researches allow D2D as an underlay to the cellular network to
increase the spectral efficiency. In this book, D2D communication underlaying
cellular networks is studied. Some physical-layer techniques and cross-layer
optimization methods on resource management and interference avoidance are
proposed and discussed. WINNER II channel models is applied to be the signal
and interference model and simulation results show that the performance of D2D
link is closely related to the distance between D2D transmitter and receiver
and that between interference source and the receiver. Besides, by power
control, D2D SINR degrades, which will naturally contribute to low interference
to cellular communication. A simple mode selection method of D2D communication
is introduced. Based on path-loss (PL) mode selection criterion, D2D gives
better performance than traditional cellular system. When D2D pair is farther
away from the BS, a better results can be obtained. Game theory, which offers a
wide variety of analytical tools to study the complex interactions of players
and predict their choices, can be used for power and radio resource management
in D2D communication. A reverse iterative combinatorial auction is formulated
as a mechanism to allocate the spectrum resources for D2D communications with
multiple user pairs sharing the same channel. In addition, a game theoretic
approach is developed to implement joint scheduling, power control and channel
allocation for D2D communication. Finally, joint power and spectrum resource
allocation method is studied under consideration of battery lifetime, which is
an important application of D2D communication on increasing user's energy
efficiency. The simulation results show that all these methods have beneficial
effects on improving the system performance.


title:
The yields of different states of Delta(1232) in neutrino-induced
  reactions at E_\nu = 10 GeV

abstract:
  First experimental data on the inclusive yields of Delta^{0}(1232) and
Delta^{+}(1232) isobars in neutrino-induced reactions are obtained. Their total
yields in neutrino-nucleon interactions, 0.145+-0.055 and 0.182+-0.054,
respectively, exceed the value of 0.091+-0.015 obtained recently for the
Delta^{++}(1232) state. The data for the all three states of Delta(1232) cannot
be reproduced by the LEPTO6.5 model. The fractions of \pi^0, \pi^- and \pi^+
mesons originating from the decay of lightest baryonic and mesonic resonances
are estimated to be, respectively 56.6+-9.6%, 39.5+-6.6% and 27.7+-3.2%.


title:
Elliptic scaling functions as compactly supported multivariate analogs
  of the B-splines

abstract:
  In the paper, we present a family of multivariate compactly supported scaling
functions, which we call as elliptic scaling functions. The elliptic scaling
functions are the convolution of elliptic splines, which correspond to
homogeneous elliptic differential operators, with distributions. The elliptic
scaling functions satisfy refinement relations with real isotropic dilation
matrices. The elliptic scaling functions satisfy most of the properties of the
univariate cardinal B-splines: compact support, refinement relation, partition
of unity, total positivity, order of approximation, convolution relation, Riesz
basis formation (under a restriction on the mask), etc. The algebraic
polynomials contained in the span of integer shifts of any elliptic scaling
function belong to the null-space of a homogeneous elliptic differential
operator. Similarly to the properties of the B-splines under differentiation,
it is possible to define elliptic (not necessarily differential) operators such
that the elliptic scaling functions satisfy relations with these operators. In
particular, the elliptic scaling functions can be considered as a composition
of segments, where the function inside a segment, like a polynomial in the case
of the B-splines, vanishes under the action of the introduced operator.


title:
Metallicity field and selection effects in spatial distribution of the
  Galactic globular cluster system

abstract:
  The prospects for using the present-day data on metallicity of globular
clusters (GCs) of the Galaxy to put constraints on the distance to the Galactic
center, $R_0$, are considered. We have found that the GCs of the metal-rich and
metal-poor subsystems separately form a bar-like structure in metallicity maps
whose parameters are very close to those for the Galactic bar. The results
indicate the existence of a bar component within both the metal-rich and
metal-poor subsystems of GCs. The bar GCs could have formed within the already
existing Galactic bar or could have later been locked in resonance with the
bar. We conclude that substantial constraints on the $R_0$ value can be
obtained only with non-axisymmetric models for the space distribution of GC
metallicities with the allowance for the subdivision of GCs into subsystems. We
found evidence for a bar extinction component that causes the observational
incompleteness of GCs in the far side of the Galactic bar and in the
"post-central" region. This selection effect should be taken into account when
determining $R_0$ from the spatial distribution of GCs.


title:
A maximum principle for systems with variational structure and an
  application to standing waves

abstract:
  We establish via variational methods the existence of a standing wave
together with an estimate on the convergence to its asymptotic states for a
bistable system of partial differential equations on a periodic domain. The
main tool is a replacement lemma which has as a corollary a maximum principle
for local minimizers.


title:
High-order splitting methods for separable non-autonomous parabolic
  equations

abstract:
  We consider the numerical integration of non-autonomous separable parabolic
equations using high order splitting methods with complex coefficients (methods
with real coefficients of order greater than two necessarily have negative
coefficients). We propose to consider a class of methods in which one set of
the coefficients are real and positive numbers, and to split properly the
system in the extended phase space where the time is taken as a new coordinate.
This allows us to evaluate all time-dependent operators at real values of the
time, leading to schemes which are stable and simple to implement. If the
system can be considered as the perturbation of an exactly solvable problem and
the flow of the dominant part is advanced using the real coefficients, it is
possible to build highly efficient methods for these problems. We show the
performance of this class of methods on several numerical examples and present
some new improved schemes.


title:
The Postage Stamp Problem - Formulae and proof for the case of 3
  denominations

abstract:
  A_k = {1, a_2, ..., a_k} is an h-basis for n if every positive integer not
exceeding n can be expressed as the sum of no more than h values a_i; an
extremal h-basis A_k is one for which n is as large as possible. Computing such
extremal bases has become known as the Postage Stamp Problem.
  In 1968 Gerd Hofmeister published formulae for solutions to the Postage Stamp
Problem with three denominations (h = 3). This paper presents an alternative
approach developed independently by the author 25 years later.


title:
SolarStat: Modeling Photovoltaic Sources through Stochastic Markov
  Processes

abstract:
  In this paper, we present a methodology and a tool to derive simple but yet
accurate stochastic Markov processes for the description of the energy
scavenged by outdoor solar sources. In particular, we target photovoltaic
panels with small form factors, as those exploited by embedded communication
devices such as wireless sensor nodes or, concerning modern cellular system
technology, by small-cells. Our models are especially useful for the
theoretical investigation and the simulation of energetically self-sufficient
communication systems including these devices. The Markov models that we derive
in this paper are obtained from extensive solar radiation databases, that are
widely available online. Basically, from hourly radiance patterns, we derive
the corresponding amount of energy (current and voltage) that is accumulated
over time, and we finally use it to represent the scavenged energy in terms of
its relevant statistics. Toward this end, two clustering approaches for the raw
radiance data are described and the resulting Markov models are compared
against the empirical distributions. Our results indicate that Markov models
with just two states provide a rough characterization of the real data traces.
While these could be sufficiently accurate for certain applications, slightly
increasing the number of states to, e.g., eight, allows the representation of
the real energy inflow process with an excellent level of accuracy in terms of
first and second order statistics. Our tool has been developed using Matlab(TM)
and is available under the GPL license at[1].


title: The coloring existence theorem revisited

abstract:
  We prove a better coloring theorem for aleph_4 and even aleph_3. This has a
general topology consequence.


title: Perfect Simulation of Determinantal Point Processes

abstract:
  Determinantal point processes (DPP) serve as a practicable modeling for many
applications of repulsive point processes. A known approach for simulation was
proposed in \cite{Hough(2006)}, which generate the desired distribution point
wise through rejection sampling. Unfortunately, the size of rejection could be
very large. In this paper, we investigate the application of perfect simulation
via coupling from the past (CFTP) on DPP. We give a general framework for
perfect simulation on DPP model. It is shown that the limiting sequence of the
time-to-coalescence of the coupling is bounded by $K|\Lambda|\log K|\Lambda|$.
An application is given to the stationary models in DPP.


title:
Breakdown of scale invariance in a quasi-two-dimensional Bose gas due to
  the presence of the third dimension

abstract:
  In this Rapid Communication, we describe how the presence of the third
dimension may break the scale invariance in a two-dimensional Bose gas in a
pancake-shaped trap. From the two-dimensional perspective, the possibility of a
weak spilling of the atomic density beyond the ground-state of the confinement
alters the two-dimensional chemical potential; in turn, this correction no
longer supports scale invariance. We compare experimental data with numerical
and analytic perturbative results and find a good agreement.


title: Problems in number theory from busy beaver competition

abstract:
  By introducing the busy beaver competition of Turing machines, in 1962, Rado
defined noncomputable functions on positive integers. The study of these
functions and variants leads to many mathematical challenges. This article
takes up the following one: How can a small Turing machine manage to produce
very big numbers? It provides the following answer: mostly by simulating
Collatz-like functions, that are generalizations of the famous 3x+1 function.
These functions, like the 3x+1 function, lead to new unsolved problems in
number theory.


title: 6D Standing Wave Braneworld with Ghost Scalar Fields

abstract:
  The 6D braneworld with the phantom-like bulk scalar field is considered. We
demonstrate pure gravitational localization of scalar field zero modes on the
brane.


title:
Fluctuating observation time ensembles in the thermodynamics of
  trajectories

abstract:
  The dynamics of stochastic systems, both classical and quantum, can be
studied by analysing the statistical properties of dynamical trajectories. The
properties of ensembles of such trajectories for long, but fixed, times are
described by large-deviation (LD) rate functions. These LD functions play the
role of dynamical free-energies: they are cumulant generating functions for
time-integrated observables, and their analytic structure encodes dynamical
phase behaviour. This "thermodynamics of trajectories" approach is to
trajectories and dynamics what the equilibrium ensemble method of statistical
mechanics is to configurations and statics. Here we show that, just like in the
static case, there is a variety of alternative ensembles of trajectories, each
defined by their global constraints, with that of trajectories of fixed total
time being just one of these. We show that an ensemble of trajectories where
some time-extensive quantity is constant (and large) but where total
observation time fluctuates, is equivalent to the fixed-time ensemble, and the
LD functions that describe one ensemble can be obtained from those that
describe the other. We discuss how the equivalence between generalised
ensembles can be exploited in path sampling schemes for generating rare
dynamical trajectories.


title: A criterion for the properness of the K-energy in a general Kahler class

abstract:
  In this paper, we give a criterion for the properness of the K-energy in a
general Kahler class of a compact Kahler manifold by using Song-Weinkove's
result. As applications, we give some Kahler classes on
$\mathbb{C}\mathbb{P}^2\#3\overline {\mathbb{C}\mathbb{P}^2}$ and
$\mathbb{C}\mathbb{P}^2\#8\overline {\mathbb{C}\mathbb{P}^2}$ in which the
K-energy is proper. Finally, we prove Song-Weinkove's result on the existence
of critical points of $\hat J$ functional by the continuity method.


title:
Nonparametric Bayesian models of hierarchical structure in complex
  networks

abstract:
  Analyzing and understanding the structure of complex relational data is
important in many applications including analysis of the connectivity in the
human brain. Such networks can have prominent patterns on different scales,
calling for a hierarchically structured model. We propose two non-parametric
Bayesian hierarchical network models based on Gibbs fragmentation tree priors,
and demonstrate their ability to capture nested patterns in simulated networks.
On real networks we demonstrate detection of hierarchical structure and show
predictive performance on par with the state of the art. We envision that our
methods can be employed in exploratory analysis of large scale complex networks
for example to model human brain connectivity.


title: Lattice polymers with two competing collapse interactions

abstract:
  There have been separate studies of the polymer collapse transition, where
the collapse was induced by two different types of attraction. In each case,
the configurations of the polymer were given by the same subset of random walks
being self-avoiding trails on the square lattice.
  Numerical evidence shows that when interacting via nearest-neighbour
contacts, this transition is different from the collapse transition in
square-lattice trails interacting via multiply visited sites. While both
transitions are second-order, when interacting via nearest-neighbour contacts,
the transition is relatively weak with a convergent specific heat, while when
interacting via multiply visited sites, the specific heat diverges strongly.
Moreover, an estimation of the crossover exponent for the nearest-neighbour
contact interaction provides a value close to that of the canonical polymer
collapse model of interacting self-avoiding walks, which also interact via
nearest-neighbour contacts.
  From computer simulations using the flatPERM algorithm, we extend these
studies by considering a model of self-avoiding trails on the square lattice
containing both types of interaction, and which therefore contains all three of
the models discussed above as special cases. We find that the strong
multiply-visited site collapse is a singular point in the phase diagram and
corresponds to a higher order multi-critical point separating a line of weak
second-order transitions from a line of first-order transitions.


title:
Hidden sector monopole, vector dark matter and dark radiation with Higgs
  portal

abstract:
  We show that the 't Hooft-Polyakov monopole model in the hidden sector with
Higgs portal interaction makes a viable dark matter model, where monopole and
massive vector dark matter (VDM) are stable due to topological conservation and
the unbroken subgroup $U(1)_X$. We show that, even though observed CMB data
requires the dark gauge coupling to be quite small, a right amount of VDM
thermal relic can be obtained via $s$-channel resonant annihilation for the
mass of VDM close to or smaller than the half of SM higgs mass, thanks to Higgs
portal interaction. Monopole relic density turns out to be several orders of
magnitude smaller than observed dark matter relic density. Direct detection
experiments, particularly, the projected XENON1T experiment, may probe the
parameter space where the dark Higgs is lighter than $\lesssim 60 {\rm GeV}$.
In addition, the dark photon associated with unbroken $U(1)_X$ contributes to
the radiation energy density at present, giving $\Delta N_{\rm eff}^\nu \sim
0.1$ as the extra relativistic neutrino species.


title:
Reduced conditional dynamic of quantum system under indirect quantum
  measurement

abstract:
  In this report, we study the reduced conditional dynamics of a quantum system
in the case of indirect quantum measurement. The detectors microscopic part
(pointer) interacts with the measured system (target) and the environment,
which results in a nonunitary interaction between target and pointer. The
quantum state evolution conditioned by the measurement result is under
investigation. Particularly, we are interested in explicit analytical
expressions for the conditional evolution superoperators and basic information
characteristics of this measurement process, which is applied to the cavity
mode photodetection problem.


title: Morphotropic Phase Boundaries in Ferromagnets: Tb_{1-x}Dy_xFe_2 Alloys

abstract:
  The structure and properties of the ferromagnet Tb_{1-x}Dy_xFe_2 (Terfenol-D)
are explored through the morphotropic phase boundary (MPB) separating ferroic
phases of differing symmetry. Our synchrotron data support a first order
structural transition, with a broadening MPB width at higher temperatures. The
optimal point for magnetomechanical applications is not centered on the MPB but
lies on the rhombohedral side, where the high striction of the rhombohedral
majority phase combines with the softened anisotropy of the MPB. We compare our
findings with single ion crystal field theory and with ferroelectric MPBs,
where the controlling energies are different.


title:
Ambiguities of the Rate of Oxygen Formation During Stellar Helium
  Burning in the 12C(a,g) Reaction

abstract:
  The rate of oxygen formation determines the C/O ratio during stellar helium
burning. It is the single most important nuclear input of stellar evolution
theory including the evolution of Type II and Type Ia supernova. Yet the low
energy cross section of the fusion of 4He + 12C denoted as the 12C(a,g)16O
reaction still remains uncertain after forty years of extensive work. We
analyze and critically review the most recent measurements of complete angular
distributions of the outgoing gamma-rays at very low energies (Ecm > 1.0 MeV).
Our analysis of the angular distribution measured with the EUROGAM/GANDI arrays
lead us to conclude considerably larger error bars than published hence they
are excluded from the current sample of "world data". We show that the current
sample of "world data" of the measured E2 cross section factors below 1.7 MeV
cluster to two distinct groups that lead to two distinct extrapolations of
SE2(300) ~ 60 or ~ 154 keVb. We point to a much neglected discrepancy between
the measured E1-E2 phase difference (phi_12) and unitarity as required by the
Watson theorem, suggesting systematic problem(s) of some of the measured
gamma-ray angular distributions. The ambiguity of the extrapolated SE2(300)
together with a previously observed ambiguity of SE1(300) represent the current
state of the art of the field and they must be resolved by future measurements
of complete and detailed angular distributions of the 12C(a,g) reaction at very
low energies (Ecm < 1.0 MeV).


title:
Maximum penalized likelihood estimation in semiparametric
  capture-recapture models

abstract:
  We discuss the semiparametric modeling of mark-recapture-recovery data where
the temporal and/or individual variation of model parameters is explained via
covariates. Typically, in such analyses a fixed (or mixed) effects parametric
model is specified for the relationship between the model parameters and the
covariates of interest. In this paper, we discuss the modeling of the
relationship via the use of penalized splines, to allow for considerably more
flexible functional forms. Corresponding models can be fitted via numerical
maximum penalized likelihood estimation, employing cross-validation to choose
the smoothing parameters in a data-driven way. Our contribution builds on and
extends the existing literature, providing a unified inferential framework for
semiparametric mark-recapture-recovery models for open populations, where the
interest typically lies in the estimation of survival probabilities. The
approach is applied to two real datasets, corresponding to grey herons (Ardea
Cinerea), where we model the survival probability as a function of
environmental condition (a time-varying global covariate), and Soay sheep (Ovis
Aries), where we model the survival probability as a function of individual
weight (a time-varying individual-specific covariate). The proposed
semiparametric approach is compared to a standard parametric (logistic)
regression and new interesting underlying dynamics are observed in both cases.


title:
Combined Independent Component Analysis and Canonical Polyadic
  Decomposition via Joint Diagonalization

abstract:
  Recently, there has been a trend to combine independent component analysis
and canonical polyadic decomposition (ICA-CPD) for an enhanced robustness for
the computation of CPD, and ICA-CPD could be further converted into CPD of a
5th-order partially symmetric tensor, by calculating the eigenmatrices of the
4th-order cumulant slices of a trilinear mixture. In this study, we propose a
new 5th-order CPD algorithm constrained with partial symmetry based on joint
diagonalization. As the main steps involved in the proposed algorithm undergo
no updating iterations for the loading matrices, it is much faster than the
existing algorithm based on alternating least squares and enhanced line search,
with competent performances. Simulation results are provided to demonstrate the
performance of the proposed algorithm.


title:
High order structure preserving explicit methods for solving
  linear-quadratic optimal control problems and differential games

abstract:
  We present high order explicit geometric integrators to solve
linear-quadratic optimal control problems and $N$-player differential games.
These problems are described by a system coupled non-linear differential
equations with boundary conditions. We propose first to integrate backward in
time the non-autonomous matrix Riccati differential equations and next to
integrate forward in time the coupled system of equations for the Riccati and
the state vector. This can be achieved by using appropriate splitting methods,
which we show they preserve most qualitative properties of the exact solution.
Since the coupled system of equations is usually explicitly time dependent, a
preliminary analysis has to be considered. We consider the time as two new
coordinates, and this allows us to integrate the whole system forward in time
using splitting methods while preserving the most relevant qualitative
structure of the exact solution. If the system is a perturbation of an exactly
solvable problem, the performance of the splitting methods considerably
improves. Some numerical examples are also considered which show the
performance of the proposed methods.


title: Testing energy non-additivity in white dwarfs

abstract:
  We consider a particular effect which can be expected in scenarios of
deviations from Special Relativity induced by Planckian physics: the loss of
additivity in the total energy of a system of particles. We argue about the
necessity to introduce a length scale to control the effects of non-additivity
for macroscopic objects and consider white dwarfs as an appropriate laboratory
to test this kind of new physics. We study the sensitivity of the mass-radius
relation of the Chandrasekhar model to these corrections by comparing the
output of a simple phenomenological model to observational data of white
dwarfs.


title: Modeling and Verification of Infinite Systems with Resources

abstract:
  We consider formal verification of recursive programs with resource
consumption. We introduce prefix replacement systems with non-negative integer
counters which can be incremented and reset to zero as a formal model for such
programs. In these systems, we investigate bounds on the resource consumption
for reachability questions. Motivated by this question, we introduce relational
structures with resources and a quantitative first-order logic over these
structures. We define resource automatic structures as a subclass of these
structures and provide an effective method to compute the semantics of the
logic on this subclass. Subsequently, we use this framework to solve the
bounded reachability problem for resource prefix replacement systems. We
achieve this result by extending the well-known saturation method to annotated
prefix replacement systems. Finally, we provide a connection to the study of
the logic cost-WMSO.


title:
Rigidity Theory in SE(2) for Unscaled Relative Position Estimation using
  only Bearing Measurements

abstract:
  This work considers the problem of estimating the unscaled relative positions
of a multi-robot team in a common reference frame from bearing-only
measurements. Each robot has access to a relative bearing measurement taken
from the local body frame of the robot, and the robots have no knowledge of a
common or inertial reference frame. A corresponding extension of rigidity
theory is made for frameworks embedded in the \emph{special Euclidean group}
$SE(2) = \mathbb{R}^2 \times \mathcal{S}^1$. We introduce definitions
describing rigidity for $SE(2)$ frameworks and provide necessary and sufficient
conditions for when such a framework is \emph{infinitesimally rigid} in
$SE(2)$. Analogous to the rigidity matrix for point formations, we introduce
the \emph{directed bearing rigidity matrix} and show that an $SE(2)$ framework
is infinitesimally rigid if and only if the rank of this matrix is equal to
$2|\mathcal{V}|-4$, where $|\mathcal{V}|$ is the number of agents in the
ensemble. The directed bearing rigidity matrix and its properties are then used
in the implementation and convergence proof of a distributed estimator to
determine the {unscaled}{} relative positions in a common frame. Some
simulation results are also given to support the analysis.


title: Analytical approach to excitonic properties of MoS2

abstract:
  We present an analytical investigation of the optical absorption spectrum of
monolayer molybdenumdisulfide. Based on the density matrix formalism, our
approach gives insights into the microscopic origin of excitonic transitions,
their relative oscillator strength, and binding energy. We show analytical
expressions for the carrier-light coupling element, which contains the optical
selection rules and well describes the valleyselective polarization in MoS2. In
agreement with experimental results, we find the formation of strongly bound
electron-hole pairs due to the efficient Coulomb interaction. The absorption
spectrum of MoS2 on a silicon substrate features two pronounced peaks at 1.91
eV and 2.05 eV corresponding to the A and B exciton, which are characterized by
binding energies of 420 meV and 440 meV, respectively. Our calculations reveal
their relative oscillator strength and predict the appearance of further
low-intensity excitonic transitions at higher energies. The presented approach
is applicable to other transition metal dichalcogenides and can be extended to
investigations of trion and biexcitonic effects.


title:
Analysis of the $Z_c(4020)$, $Z_c(4025)$, $Y(4360)$ and $Y(4660)$ as
  vector tetraquark states with QCD sum rules

abstract:
  In this article, we distinguish the charge conjugations of the interpolating
currents, calculate the contributions of the vacuum condensates up to
dimension-10 in the operator product expansion, and study the masses and pole
residues of the $J^{PC}=1^{-\pm}$ hidden charmed tetraquark states with the QCD
sum rules. We suggest a formula $\mu=\sqrt{M^2_{X/Y/Z}-(2{\mathbb{M}}_c)^2}$
with the effective mass ${\mathbb{M}}_c=1.8\,\rm{GeV}$ to estimate the energy
scales of the QCD spectral densities of the hidden charmed tetraquark states,
which works very well. The numerical results disfavor assigning the
$Z_c(4020)$, $Z_c(4025)$, $Y(4360)$ as the diquark-antidiquark (with the Dirac
spinor structure $C-C\gamma_\mu$) type vector tetraquark states, and favor
assigning the $Z_c(4020)$, $Z_c(4025)$ as the diquark-antidiquark type $1^{+-}$
tetraquark states. While the masses of the tetraquark states with symbolic
quark structures $c\bar{c}s\bar{s}$ and $c\bar{c}(u\bar{u}+d\bar{d})/\sqrt{2}$
favor assigning the $Y(4660)$ as the $1^{--}$ diquark-antidiquark type
tetraquark state, more experimental data are still needed to distinguish its
quark constituents. There are no candidates for the positive charge conjugation
vector tetraquark states, the predictions can be confronted with the
experimental data in the future at the BESIII, LHCb and Belle-II.


title:
A Geometric Approach to Sound Source Localization from Time-Delay
  Estimates

abstract:
  This paper addresses the problem of sound-source localization from time-delay
estimates using arbitrarily-shaped non-coplanar microphone arrays. A novel
geometric formulation is proposed, together with a thorough algebraic analysis
and a global optimization solver. The proposed model is thoroughly described
and evaluated. The geometric analysis, stemming from the direct acoustic
propagation model, leads to necessary and sufficient conditions for a set of
time delays to correspond to a unique position in the source space. Such sets
of time delays are referred to as feasible sets. We formally prove that every
feasible set corresponds to exactly one position in the source space, whose
value can be recovered using a closed-form localization mapping. Therefore we
seek for the optimal feasible set of time delays given, as input, the received
microphone signals. This time delay estimation problem is naturally cast into a
programming task, constrained by the feasibility conditions derived from the
geometric analysis. A global branch-and-bound optimization technique is
proposed to solve the problem at hand, hence estimating the best set of
feasible time delays and, subsequently, localizing the sound source. Extensive
experiments with both simulated and real data are reported; we compare our
methodology to four state-of-the-art techniques. This comparison clearly shows
that the proposed method combined with the branch-and-bound algorithm
outperforms existing methods. These in-depth geometric understanding, practical
algorithms, and encouraging results, open several opportunities for future
work.


title:
Using linear gluon polarization inside an unpolarized proton to
  determine the Higgs spin and parity

abstract:
  Gluons inside an unpolarized proton are in general linearly polarized in the
direction of their transverse momentum, rendering the LHC effectively a
polarized gluon collider. This polarization can be utilized in the
determination of the spin and parity of the newly found Higgs-like boson. We
focus here on the determination of the spin using the azimuthal Collins-Soper
angle $\phi$ distribution.


title:
Ultrasensitive microwave spectroscopy of paramagnetic impurities of
  sapphire crystals at millikelvin temperatures

abstract:
  Progress in the emerging field of engineered quantum systems requires the
development of devices that can act as quantum memories. The realisation of
such devices by doping solid state cavities with paramagnetic ions imposes a
trade-off between ion concentration and cavity coherence time. Here, we
investigate an alternative approach involving interactions between photons and
naturally occurring impurity ions in ultra-pure crystalline microwave cavities
exhibiting exceptionally high quality factors. We implement a hybrid Whispering
Gallery/Electron Spin Resonance method to perform rigorous spectroscopy of an
undoped single-crystal sapphire resonator over the frequency range 8--19 GHz,
and at external applied DC magnetic fields up to 0.9 T. Measurements of a high
purity sapphire cooled close to 100 mK reveal the presence of Fe$^{3+}$,
Cr$^{3+}$, and V$^{2+}$ impurities. A host of electron transitions are measured
and identified, including the two-photon classically forbidden quadrupole
transition ($\Delta m_s =2$) for Fe$^{3+}$, as well as hyperfine transitions of
V$^{2+}$.


title:
Speeding up low-mass planetary microlensing simulations and modelling:
  the Caustic Region Of INfluence

abstract:
  Extensive simulations of planetary microlensing are necessary both before and
after a survey is conducted: before to design and optimize the survey and after
to understand its detection efficiency. The major bottleneck in such
computations is the computation of lightcurves. However, for low-mass planets
most of these computations are wasteful, as most lightcurves do not contain
detectable planetary signatures. In this paper I develop a parameterization of
the binary microlens that is conducive to avoiding lightcurve computations. I
empirically find analytic expressions describing the limits of the parameter
space that contain the vast majority of low-mass planet detections. Through a
large scale simulation I measure the (in)completeness of the parameterization
and the speed-up it is possible to achieve. For Earth-mass planets in a wide
range of orbits it is possible to speed up simulations by a factor of ${\sim}
30$-$125$ (depending on the survey's annual duty-cycle) at the cost of missing
${\sim} 1$ percent of detections (which is actually a smaller loss than for the
arbitrary parameter limits typically applied in microlensing simulations). The
benefits of the parameterization probably outweigh the costs for planets below
$100M_{\oplus}$. For planets at the sensitivity limit of AFTA-WFIRST,
simulation speed-ups of a factor ${\sim} 1000$ or more are possible.


title: On Homology Roses and the D(2)-problem

abstract:
  For a commutative ring $R$ with a unit, an $R$-homology rose is a topological
space whose homology groups with $R$-coefficients agree with those of a bouquet
of cirlces. In this paper, we study some special properties of covering spaces
and fundamental groups of $R$-homology roses, from which we obtain some result
supporting the Carlsson conjecture on free $(Z_p)^r$ actions. In addition, for
a group $G$ and a field $F$, we define an integer called the $F$-gap of $G$,
which is an obstruction for $G$ to be realized as the fundamental group of a
2-dimensional $F$-homology rose. Furthermore, we discuss how to search
candidates of the counterexamples of Wall's D(2)-problem among $F$-homology
roses and $F$-acyclic spaces.


title: eta' multiplicity and Witten-Veneziano relation at T>0

abstract:
  Recent RHIC results on eta' multiplicity in heavy-ion collisions are of great
importance because they clearly signal a partial restoration of U_A(1) symmetry
at high temperatures T, and thus provide an unambiguous signature of the
formation of a new state of matter. Prompted by these experimental results of
STAR and PHENIX collaborations, we discuss and propose the minimal
generalization of the Witten-Veneziano relation to finite T.


title:
Guessing a password over a wireless channel (on the effect of noise
  non-uniformity)

abstract:
  A string is sent over a noisy channel that erases some of its characters.
Knowing the statistical properties of the string's source and which characters
were erased, a listener that is equipped with an ability to test the veracity
of a string, one string at a time, wishes to fill in the missing pieces. Here
we characterize the influence of the stochastic properties of both the string's
source and the noise on the channel on the distribution of the number of
attempts required to identify the string, its guesswork. In particular, we
establish that the average noise on the channel is not a determining factor for
the average guesswork and illustrate simple settings where one recipient with,
on average, a better channel than another recipient, has higher average
guesswork. These results stand in contrast to those for the capacity of wiretap
channels and suggest the use of techniques such as friendly jamming with
pseudo-random sequences to exploit this guesswork behavior.


title: The OIV 1407.3\AA /1401.1\AA\ emission-line ratio in a plasma

abstract:
  Line ratio of O IV 1407.3 \AA/1401.1 \AA\- is calculated using mostly our own
atomic and collisional data. Energy levels and oscillator strengths needed for
this calculation have been calculated using a Hartree-Fock relativistic (HFR)
approach. The electron collision strengths introduced in the statistic
equilibrium equations are fitted by polynomials for different energies.
Comparison has also been made with available theoretical results. The provided
line ratio has been obtained for a set of electron densities from $10^{8}$
cm$^{-3}$ to $10^{13}$ cm$^{-3}$ and for a fixed temperature of 50 000 K.


title:
An Algorithm of Logistic Costs Minimization Under Constraints on Supply
  Volumes

abstract:
  A problem of minimization of delivery and storage costs of a product is
considered under constraints on volumes of delivery from each of the suppliers.
It is required to determine optimal volumes and times of product shipments. The
problem is NP-hard. In this paper, the problem is proved to be
pseudo-polynomially solvable and an algorithm for its solution is proposed.


title: Adaptive gauge cooling for complex Langevin dynamics

abstract:
  In the case of nonabelian gauge theories with a complex weight, a controlled
exploration of the complexified configuration space during a complex Langevin
process requires the use of SL(N,C) gauge cooling, in order to minimize the
distance from SU(N). Here we show that adaptive gauge cooling can lead to an
efficient implementation of this idea. First results for SU(3) Yang-Mills
theory in the presence of a nonzero theta-term are presented as well.