title:
Pattern-Coupled Sparse Bayesian Learning for Recovery of Block-Sparse
  Signals

abstract:
  We consider the problem of recovering block-sparse signals whose structures
are unknown \emph{a priori}. Block-sparse signals with nonzero coefficients
occurring in clusters arise naturally in many practical scenarios. However, the
knowledge of the block structure is usually unavailable in practice. In this
paper, we develop a new sparse Bayesian learning method for recovery of
block-sparse signals with unknown cluster patterns. Specifically, a
pattern-coupled hierarchical Gaussian prior model is introduced to characterize
the statistical dependencies among coefficients, in which a set of
hyperparameters are employed to control the sparsity of signal coefficients.
Unlike the conventional sparse Bayesian learning framework in which each
individual hyperparameter is associated independently with each coefficient, in
this paper, the prior for each coefficient not only involves its own
hyperparameter, but also the hyperparameters of its immediate neighbors. In
doing this way, the sparsity patterns of neighboring coefficients are related
to each other and the hierarchical model has the potential to encourage
structured-sparse solutions. The hyperparameters, along with the sparse signal,
are learned by maximizing their posterior probability via an
expectation-maximization (EM) algorithm. Numerical results show that the
proposed algorithm presents uniform superiority over other existing methods in
a series of experiments.


title: Photon emission in neutral current interactions at intermediate energies

abstract:
  Neutral current photon emission reactions with nucleons and nuclei are
studied. These processes are important backgrounds for nu_mu to nu_e
(bar(nu)_mu to bar(nu)_e) appearance oscillation experiments where
electromagnetic showers instigated by electrons (positrons) and photons are not
distinguishable. At intermediate energies, these reactions are dominated by the
weak excitation of the Delta(1232) resonance and its subsequent decay into
Ngamma There are also non-resonant contributions that, close to threshold, are
fully determined by the effective chiral Lagrangian of strong interactions. In
addition, we have also included mechanisms mediated by nucleon excitations (N*)
from the second resonance region above the Delta(1232). From these states, the
contribution of the D13 N*(1520) turns out to be sizable for (anti)neutrino
energies above 1.5 GeV. We have extended the model to nuclear targets taking,
into account Pauli blocking, Fermi motion and the in-medium Delta resonance
broadening. We present our predictions for both the incoherent and coherent
channels, showing the relevance of the nuclear corrections. We also discuss the
target mass dependence of the cross sections. This study is important in order
to reduce systematic effects in neutrino oscillation experiments.


title:
Direct Numerical Simulation of Reionization II: Recombinations, Clumping
  Factors, and the Photon Budget for Reionization

abstract:
  In this first of several application papers, we investigate the mechanics of
reionization from stellar sources in high-z galaxies, the utility of various
clumping factors on estimating the recombination time in the IGM, and the
photon budget required to achieve reionization. We test the accuracy of the
static and time-dependent models of Madau et al. as predictors of reionization
completion/maintenance. We simulate a WMAP7 LCDM cosmological model in a 20 Mpc
comoving cube with 800^3 uniform fluid cells and dark matter particles. By
tuning our star formation to approximately match the observed star formation
rate density and luminosity function, we created a fully coupled
radiation-hydro realization of H reionization which begins to ionize at z~10
and completes at z~5.8. We find that roughly 2 ionizing photons per H atom are
required to convert the neutral IGM to a highly ionized state, which supports
the "photon starved" scenario discussed by Bolton & Haehnelt. The events during
reionization that lead to this number can generally be described as inside-out,
but in reality the narrative depends on the level of ionization of the gas one
attributes to as ionized. We find that the formula for the UV photon production
rate dN/dt_ion(z) needed to maintain the IGM in an ionized state derived by
Madau et al. should not be used to predict the epoch of reionization completion
because it ignores history-dependent terms in the global ionization balance
which are not ignorable. We find that the time-dependent model for the ionized
volume fraction Q_HII is more predictive, but overestimates the redshift of
reionization completion by delta_z~1. We propose a revised formulation of the
time-dependent model which agrees with our simulation to O(1%). Finally, we use
our simulation to estimate a global UV escape fraction due to circumgalactic
gas resolved on our mesh to be <f_esc>~0.7.


title:
The neutron star in Cassiopeia A: equation of state, superfluidity, and
  Joule heating

abstract:
  The thermomagnetic evolution of the young neutron star in Cassiopea A is
studied by considering fast neutrino emission processes. In particular, we
consider neutron star models obtained from the equation of state computed in
the framework of the Brueckner-Bethe-Goldstone many-body theory and variational
methods, and models obtained with the Akmal-Pandharipande-Ravenhall equation of
state. It is shown that it is possible to explain a fast cooling regime as the
one observed in the neutron star in Cassiopea A if the Joule heating produced
by dissipation of the small-scale magnetic field in the crust is taken into
account. We thus argue that it is difficult to put severe constraints on the
superfluid gap if the Joule heating is considered.


title:
The compositional inverses of linearized permutation binomials over
  finite fields

abstract:
  Let $q$ be a prime power and $n$ and $r$ be positive integers. It is well
known that the linearized binomial $L_r(x)=x^{q^r}+ax\in\mathbb{F}_{q^n}[x]$ is
a permutation polynomial if and only if
$(-1)^{n/d}a^{{(q^n-1)}/{(q^{d}-1)}}\neq 1$ where $d=(n,r)$. In this paper, the
compositional inverse of $L_r(x)$ is explicitly determined when this condition
holds.


title: On negative results concerning Hardy means

abstract:
  In the present paper we are going to prove some necessary condition for a
mean to be Hardy. This condition is then applied to completely characterize the
Hardy property among the Gini means.


title:
Beyond the Dicke Quantum Phase Transition with a Bose-Einstein
  Condensate in an Optical Ring Resonator

abstract:
  We experimentally investigate the dynamical instability of a Bose Einstein
condensate in an optical ring resonator for various cavity detuning and pump
powers. The resulting phase diagram is asymmetric with respect to the cavity
detuning and can be described by the coupling of two atomic modes with one
optical mode. We compare the experimental data to a numerical simulation and to
an analytic expression of the phase boundary. For positive and negative pump
cavity detuning different coupling mechanisms are identified explaining the
asymmetry of the phase diagram. We present a physical interpretation and
discuss the connection to the Dicke quantum phase transition.


title:
The derivation of the conservation law for defocusing nonlinear
  Schroedinger equations with non-vanishing initial data at infinity

abstract:
  For nonlinear Schr\"odinger equations in less than or equal to four
dimension, with non-vanishing initial data at infinity, a new approach to
derive the conservation law is obtained. Since this approach does not contain
approximating procedure, the argument is simplified and some of technical
assumption of the nonlinearity to derive the conservation law and time global
solutions, is removed.


title:
Atomized Spraying of Liquid Metal Droplets on Desired Substrate Surfaces
  as a Generalized Way for Ubiquitous Printed Electronics

abstract:
  A direct electronics printing technique through atomized spraying for
patterning room temperature liquid metal droplets on desired substrate surfaces
is proposed and experimentally demonstrated for the first time. This method has
generalized purpose and is highly flexible and capable of fabricating
electronic components on any desired target objects, with either flat or rough
surfaces, made of different materials, or different orientations from 1-D to
3-D geometrical configurations. With a pre-designed mask, the liquid metal ink
can be directly deposited on the substrate to form various specific patterns
which lead to the rapid prototyping of electronic devices. Further, extended
printing strategies were also suggested to illustrate the adaptability of the
method such that the natural porous structure can be adopted to offer an
alternative way of making transparent conductive film with an optical
transmittance of 47% and a sheet resistance of 5.167{\Omega}/O. Different from
the former direct writing technology where large surface tension and poor
adhesion between the liquid metal and the substrate often impede the flexible
printing process, the liquid metal here no longer needs to be pre-oxidized to
guarantee its applicability on target substrates. One critical mechanism was
found as that the atomized liquid metal microdroplets can be quickly oxidized
in the air due to its large specific surface area, resulting in a significant
increase of the adhesive capacity and thus firm deposition of the ink to the
substrate. This study established a generalized way for pervasively and
directly printing electronics on various substrates which are expected to be
significant in a wide spectrum of electrical engineering areas.

categories: cond-mat.mtrl-sci cond-mat.mes-hall cond-mat.other physics.flu-dyn physics.ins-det


title: Algebraic elliptic cohomology theory and flops, I

abstract:
  We define the algebraic elliptic cohomology theory coming from Krichever's
elliptic genus as an oriented cohomology theory on smooth varieties over an
arbitrary perfect field. We show that in the algebraic cobordism ring with
rational coefficients, the ideal generated by differences of classical flops
coincides with the kernel of Krichever's elliptic genus. This generalizes a
theorem of B. Totaro in the complex analytic setting.


title: Excluded minors and the ribbon graphs of knots

abstract:
  In this paper we consider minors of ribbon graphs (or, equivalently,
cellularly embedded graphs). The theory of minors of ribbon graphs differs from
that of graphs in that contracting loops is necessary and doing this can create
additional vertices and components. Thus the ribbon graph minor relation is
incompatible with the graph minor relation. We discuss excluded minor
characterisations of minor closed families of ribbon graphs. Our main result is
an excluded minor characterisation of the family of ribbon graphs that
represent knot and link diagrams.


title: Convergence Results for Two Kahler-Ricci Flows

abstract:
  In this note, we provide some general discussion on the two main versions in
the study of Kahler-Ricci flows over closed manifolds, aiming at smooth
convergence to the corresponding Kahler-Einstein metrics with assumptions on
the volume form and Ricci curvature form along the flow.


title: Mixed (Cold+Warm) Dark Matter in the Bino-Wino co-annihilation scenario

abstract:
  We study phenomenological aspects of the bino-wino co-annihilation scenario
in high-scale supersymmetry breaking models. High-scale SUSY breaking scenarios
are considered to be promising possibility after the discovery of the Higgs
boson with a mass around 126 GeV. In this paper, we discuss the bino lightest
supersymmetric particle (LSP) accompanied by the at most around 30 GeV heavier
wino. With the suitable mass splitting between the bino and the wino, the bino
LSP has the correct relic abundance of dark matter. For the smaller mass
splitting, the late-time decay of the gravitino can provide the correct
abundance of the bino dark matter. It is extremely challenging to find signals
from the bino dark matter in direct and indirect detections. By utilizing
multi-jets plus missing transverse momentum events at the LHC, we can
constraint the gluino mass and thus probe the bino-wino co-annihilation
scenario indirectly. The collider experiment, however, can not search the bino
dark matter directly. In this paper, we suggest the direct probe of the bino
dark matter. We show that the bino dark matter leaves imprints on the
small-scale matter power spectrum when the bino dark matter is produced by the
decay of the gravitino. The non-thermal bino dark matter behaves as mixed
(cold+warm) dark matter.


title: Regularized trace formula of magic Gribov operator on Bargmann space

abstract:
  In this article, we obtain a regularized trace formula for magic Gribov
operator\\ $ H = \lambda{''}G + H_{\mu,\lambda}$ acting on Bargmann space where
$$G = a^{*3}a^{3} \quad \quad and \quad \quad H_{\mu,\lambda} = \mu a^{*}a +
i\lambda a^{*}(a + a^{*})a$$ Here $a$ and $a^{*}$ are the standard Bose
annihilation and creation operators and in Reggeon field theory, the real
parameters $\lambda{''}$ is the magic coupling of Pomeron, $\mu$ is Pomeron
intercept, $\lambda$ is the triple coupling of Pomeron and $i^{2} = -1$. An
exact relation is established between the degree of subordination of the
perturbation operator $H_{\mu,\lambda}$ to the unperturbed operator $G$ and the
number of corrections necessary for the existence of finite formula of the
trace.


title:
AA stacking, tribological and electronic properties of double-layer
  graphene with krypton spacer

abstract:
  Structural, energetic and tribological characteristics of double-layer
graphene with commensurate and incommensurate krypton spacers of nearly
monolayer coverage are studied within the van der Waals-corrected density
functional theory. It is shown that when the spacer is in the commensurate
phase, the graphene layers have the AA stacking. For this phase, the barriers
to relative in-plane translational and rotational motion and the shear mode
frequency of the graphene layers are calculated. For the incommensurate phase,
both of the barriers are found to be negligibly small. A considerable change of
tunneling conductance between the graphene layers separated by the commensurate
krypton spacer at their relative subangstrom displacement is revealed by the
use of the Bardeen method. The possibility of nanoelectromechanical systems
based on the studied tribological and electronic properties of the considered
heterostructures is discussed.


title: Phase relation between global temperature and atmospheric carbon dioxide

abstract:
  The primary ingredient of Anthropogenic Global Warming hypothesis is the
assumption that atmospheric carbon dioxide variations are the cause for
temperature variations. In this paper we discuss this assumption and analyze it
on basis of bi-centenary measurements and using a relaxation model which causes
phase shifts and delays.


title:
Auxiliary-variable Exact Hamiltonian Monte Carlo Samplers for Binary
  Distributions

abstract:
  We present a new approach to sample from generic binary distributions, based
on an exact Hamiltonian Monte Carlo algorithm applied to a piecewise continuous
augmentation of the binary distribution of interest. An extension of this idea
to distributions over mixtures of binary and possibly-truncated Gaussian or
exponential variables allows us to sample from posteriors of linear and probit
regression models with spike-and-slab priors and truncated parameters. We
illustrate the advantages of these algorithms in several examples in which they
outperform the Metropolis or Gibbs samplers.


title: SPH Entropy Errors and the Pressure Blip

abstract:
  The spurious pressure jump at a contact discontinuity, in SPH simulations of
the compressible Euler equations is investigated. From the spatiotemporal
behaviour of the error, the SPH pressure jump is likened to entropy errors
observed for artificial viscosity based finite difference/volume schemes. The
error is observed to be generated at start-up and dissipation is the only
recourse to mitigate it's effect. We show that similar errors are generated for
the Lagrangian plus remap version of the Piecewise Parabolic Method (PPM)
finite volume code (PPMLR). Through a comparison with the direct Eulerian
version of the PPM code (PPMDE), we argue that a lack of diffusion across the
material wave (contact discontinuity) is responsible for the error in PPMLR. We
verify this hypothesis by constructing a more dissipative version of the remap
code using a piecewise constant reconstruction. As an application to SPH, we
propose a hybrid GSPH scheme that adds the requisite dissipation by utilizing a
more dissipative Riemann solver for the energy equation. The proposed
modification to the GSPH scheme, and it's improved treatment of the anomaly is
verified for flows with strong shocks in one and two dimensions. The result
that dissipation must act across the density and energy equations provides a
consistent explanation for many of the hitherto proposed "cures" or "fixes" for
the problem.


title: The Lagrangian-space Effective Field Theory of Large Scale Structures

abstract:
  We introduce a Lagrangian-space Effective Field Theory (LEFT) formalism for
the study of cosmological large scale structures. Unlike the previous
Eulerian-space construction, it is naturally formulated as an effective field
theory of extended objects in Lagrangian space. In LEFT the resulting finite
size effects are described using a multipole expansion parameterized by a set
of time dependent coefficients and organized in powers of the ratio of the
wavenumber of interest $k$ over the non-linear scale $k_{\rm NL}$. The
multipoles encode the effects of the short distance modes on the
long-wavelength universe and absorb UV divergences when present. There are no
IR divergences in LEFT. Some of the parameters that control the perturbative
approach are not assumed to be small and can be automatically resummed. We
present an illustrative one-loop calculation for a power law universe. We
describe the dynamics both at the level of the equations of motion and through
an action formalism.


title: Collective foraging in heterogeneous landscapes

abstract:
  Animals foraging alone are hypothesized to optimize the encounter rates with
resources through L\'evy walks. However, the issue of how the interactions
between multiple foragers influence their search efficiency is still not
completely understood. To address this, we consider a model to study the
optimal strategy for a group of foragers searching for targets distributed
heterogeneously. In our model foragers move on a square lattice containing
immobile but regenerative targets. At any instant a forager is able to detect
only those targets that happen to be in the same site. However, we allow the
foragers to have information about the state of other foragers. A forager who
has not detected any target walks towards the nearest location, where another
forager has detected a target, with probability $\exp{\left(-\alpha d\right)}$,
where $d$ is the distance and $\alpha$ is a parameter. The model reveals that
neither overcrowding ($\alpha\to 0$) nor independent searching
($\alpha\to\infty$) is beneficial for the group. For patchy distribution of
targets the efficiency is maximum for intermediate values of $\alpha$. Also, in
the limit $\alpha\to 0$, the length of the walks can become scale-free.


title:
Fixed points of diffeomorphisms, singularities of vector fields and
  epsilon-neighborhoods of their orbits, the thesis

abstract:
  The thesis deals with recognizing diffeomorphisms from fractal properties of
discrete orbits, generated by iterations of such diffeomorphisms. The notion of
fractal properties of a set refers to the box dimension, the Minkowski content
and their appropriate generalizations, or, in wider sense, to the
epsilon-neighborhoods of sets, for small, positive values of parameter epsilon.
In the first part of the thesis, we consider the relation between the
multiplicity of the fixed point of a real-line diffeomorphism, and the
asymptotic behavior of the length of the epsilon-neighborhoods of its orbits.
We establish the bijective correspondence. At the fixed point, the
diffeomorphisms may be differentiable or nondifferentiable. The results are
applied to the question of cyclicity of some planar limit periodic sets of
polynomial fields, whose first return maps are real-line diffeomorphisms. In
the second part of the thesis, we consider the relation between formal and
analytic classes of complex diffeomorphisms f:C->C and epsilon-neighborhoods of
their orbits. It is shown that the formal class can be read from generalized
fractal properties of any orbit. The results are directly applied to formal
classification of complex saddles in C^2. On the other hand, concerning the
analytic classification, we state problems in reading the analytic class of a
diffeomorphisms from epsilon-neighborhoods of orbits.


title: Trace formulae for curvature of Jet Bundles over planar domain

abstract:
  For a domain \Omega in \mathbb{C} and an operator T in \mathcal{B}_n(\Omega),
Cowen and Douglas construct a Hermitian holomorphic vector bundle E_T over
\Omega corresponding to T. The Hermitian holomorphic vector bundle E_T is
obtained as a pull-back of the tautological bundle S(n,\mathcal{H}) defined
over \mathcal{G}r(n,\mathcal{H}) by a nondegenerate holomorphic map z\mapsto
{\rm{ker}}(T-z) for z\in\Omega. To find the answer to the converse, Cowen and
Douglas studied the jet bundle in their foundational paper. The computations in
this paper for the curvature of the jet bundle are somewhat difficult to
comprehend. They have given a set of invariants to determine if two rank n
Hermitian holomorphic vector bundle are equivalent. These invariants are
complicated and not easy to compute. It is natural to expect that the
equivalence of Hermitian holomorphic jet bundles should be easier to
characterize. In fact, in the case of the Hermitian holomorphic jet bundle
\mathcal{J}_k(\mathcal{L}_f), we have shown that the curvature of the line
bundle \mathcal{L}_f completely determines the class of
\mathcal{J}_k(\mathcal{L}_f). In case of rank n Hermitian Holomorphic vector
bundle E_f, We have calculated the curvature of jet bundle \mathcal{J}_k(E_f)
and also have generalized the trace formula for jet bundle \mathcal{J}_k(E_f).


title:
Entanglement of three cavity fields via resonant interactions with
  dressed three-level atoms

abstract:
  In this paper we show that three cavity fields can be entangled when they are
tuned on resonance with an ensemble of dressed three-level atoms. The master
equation for the three cavity modes is derived by using atomic dressed states
and the inseparability of the three output cavity modes is described by using a
sufficient criterion proposed by van Loock and Furusawa. The physical cause is
the atomic coherence effects, by which the quantum correlations are created in
the field dynamics.


title:
Noether symmetries and analytical solutions in f(T)-cosmology: A
  complete study

abstract:
  We investigate the main features of the flat
Friedmann-Lema{\i}tre-Robertson-Walker cosmological models in the f(T)
teleparallel gravity. In particular, a general approach to find out exact
cosmological solutions in f (T) gravity is discussed. Instead of taking into
account phenomenological models, we consider as a selection criterion, the
existence of Noether symmetries in the cosmological f(T) point-like Lagrangian.
We find that only power-law models admit extra Noether symmetries. A complete
analysis of such cosmological models is developed.


title: Pressure exerted by a vesicle on a surface

abstract:
  Several recent works have considered the pressure exerted on a wall by a
model polymer. We extend this consideration to vesicles attached to a wall, and
hence include osmotic pressure. We do this by considering a two-dimensional
directed model, namely that of area-weighted Dyck paths.
  Not surprisingly, the pressure exerted by the vesicle on the wall depends on
the osmotic pressure inside, especially its sign. Here, we discuss the scaling
of this pressure in the different regimes, paying particular attention to the
crossover between positive and negative osmotic pressure. In our directed
model, there exists an underlying Airy function scaling form, from which we
extract the dependence of the bulk pressure on small osmotic pressures.

categories: cond-mat.stat-mech cond-mat.soft math-ph math.MP


title:
The full infinite dimensional moment problem on semi-algebraic sets of
  generalized functions

abstract:
  We consider a generic basic semi-algebraic subset $\mathcal{S}$ of the space
of generalized functions, that is a set given by (not necessarily countably
many) polynomial constraints. We derive necessary and sufficient conditions for
an infinite sequence of generalized functions to be realizable on
$\mathcal{S}$, namely to be the moment sequence of a finite measure
concentrated on $\mathcal{S}$. Our approach combines the classical results
about the moment problem on nuclear spaces with the techniques recently
developed to treat the moment problem on basic semi-algebraic sets of
$\mathbb{R}^d$. In this way, we determine realizability conditions that can be
more easily verified than the well-known Haviland type conditions. Our result
completely characterizes the support of the realizing measure in terms of its
moments. As concrete examples of semi-algebraic sets of generalized functions,
we consider the set of all Radon measures and the set of all the measures
having bounded Radon-Nikodym density w.r.t. the Lebesgue measure.


title:
Phase space gradient of dissipated work and information: A role of
  relative Fisher information

abstract:
  We show that an information theoretic distance measured by the relative
Fisher information between canonical equilibrium phase densities corresponding
to forward and backward processes is intimately related to the gradient of the
dissipated work in phase space. We present a universal constraint on it via the
logarithmic Sobolev inequality. Furthermore, we point out that a possible
expression of the lower bound indicates a deep connection in terms of the
relative entropy and the Fisher information of the canonical distributions.


title: On duality of diameter 2 properties

abstract:
  It is known that a Banach space has the strong diameter 2 property (i.e.
every convex combination of slices of the unit ball has diameter 2) if and only
if the norm on its dual space is octahedral (a notion introduced by Godefroy
and Maurey). We introduce two more versions of octahedrality, which turn out to
be dual properties to the diameter 2 property and its local version (i.e.,
respectively, every relatively weakly open subset and every slice of the unit
ball has diameter 2). We study stability properties of different types of
octahedrality, which, by duality, provide easier proofs of many known results
on diameter 2 properties.


title: Topological completeness of logics above S4

abstract:
  It is a celebrated result of McKinsey and Tarski [28] that S4 is the logic of
the closure algebra X+ over any dense-in-itself separable metrizable space. In
particular, S4 is the logic of the closure algebra over the reals R, the
rationals Q, or the Cantor space C. By [5], each logic above S4 that has the
finite model property is the logic of a subalgebra of Q+, as well as the logic
of a subalgebra of C+. This is no longer true for R, and the main result of [5]
states that each connected logic above S4 with the finite model property is the
logic of a subalgebra of the closure algebra R+. In this paper we extend these
results to all logics above S4. Namely, for a normal modal logic L, we prove
that the following conditions are equivalent: (i) L is above S4, (ii) L is the
logic of a subalgebra of Q+, (iii) L is the logic of a subalgebra of C+. We
introduce the concept of a well-connected logic above S4 and prove that the
following conditions are equivalent: (i) L is a well-connected logic, (ii) L is
the logic of a subalgebra of the closure algebra T_2^+ over the infinite binary
tree, (iii) L is the logic of a subalgebra of the closure algebra L_2^+ over
the infinite binary tree with limits equipped with the Scott topology. Finally,
we prove that a logic L above S4 is connected iff L is the logic of a
subalgebra of R+, and transfer our results to the setting of intermediate
logics.


title:
Twist free energy and critical behavior of 3D U(1) LGT at finite
  temperature

abstract:
  The twist free energy is computed in the Villain formulation of the 3D U(1)
lattice gauge theory at finite temperature. This enables us to obtain
renormalization group equations describing a critical behavior of the model in
the vicinity of the deconfinement phase transition. These equations are used to
check the validity of the Svetitsky-Yaffe conjecture regarding the critical
behavior of the lattice U(1) model. In particular, we calculate the two-point
correlation function of the Polyakov loops and determine some critical indices.


title: Adaptive Epidemic Dynamics in Networks: Thresholds and Control

abstract:
  Theoretical modeling of computer virus/worm epidemic dynamics is an important
problem that has attracted many studies. However, most existing models are
adapted from biological epidemic ones. Although biological epidemic models can
certainly be adapted to capture some computer virus spreading scenarios
(especially when the so-called homogeneity assumption holds), the problem of
computer virus spreading is not well understood because it has many important
perspectives that are not necessarily accommodated in the biological epidemic
models. In this paper we initiate the study of such a perspective, namely that
of adaptive defense against epidemic spreading in arbitrary networks. More
specifically, we investigate a non-homogeneous
Susceptible-Infectious-Susceptible (SIS) model where the model parameters may
vary with respect to time. In particular, we focus on two scenarios we call
semi-adaptive defense and fully-adaptive} defense, which accommodate implicit
and explicit dependency relationships between the model parameters,
respectively. In the semi-adaptive defense scenario, the model's input
parameters are given; the defense is semi-adaptive because the adjustment is
implicitly dependent upon the outcome of virus spreading. For this scenario, we
present a set of sufficient conditions (some are more general or succinct than
others) under which the virus spreading will die out; such sufficient
conditions are also known as epidemic thresholds in the literature. In the
fully-adaptive defense scenario, some input parameters are not known (i.e., the
aforementioned sufficient conditions are not applicable) but the defender can
observe the outcome of virus spreading. For this scenario, we present adaptive
control strategies under which the virus spreading will die out or will be
contained to a desired level.


title:
Achieving synchronization in arrays of coupled differential systems with
  time-varying couplings

abstract:
  In this paper, we study complete synchronization of the complex dynamical
networks described by linearly coupled ordinary differential equation systems
(LCODEs). The coupling considered here is time-varying in both the network
structure and the reaction dynamics. Inspired by our previous paper [6], the
extended Hajnal diameter is introduced and used to measure the synchronization
in a general differential system. Then we find that the Hajnal diameter of the
linear system induced by the time-varying coupling matrix and the largest
Lyapunov exponent of the synchronized system play the key roles in
synchronization analysis of LCODEs with the identity inner coupling matrix. As
an application, we obtain a general sufficient condition guaranteeing directed
time-varying graph to reach consensus. Example with numerical simulation is
provided to show the effectiveness the theoretical results.


title: Surface morphology of a modified ballistic deposition model

abstract:
  The surface and bulk properties of a modified ballistic deposition model are
investigated. The deposition rule interpolates between nearest and next-nearest
neighbor ballistic deposition and the random deposition models. The stickiness
of the depositing particle is controlled by a parameter and the type of
inter-particle force. Two such forces are considered - Coulomb and van der
Waals type. The interface width shows three distinct growth regions before
eventual saturation. The rate of growth depends more strongly on the stickiness
parameter than on the type of inter-particle force. However, the porosity of
the deposits is strongly influenced by the inter-particle force.


title:
Prompt Optical Emission from Gamma-ray Bursts with Non-single Timescale
  Variability of Central Engine Activities

abstract:
  The complete high-resolution lightcurves of Swift GRB 080319B present an
opportunity for detailed temporal analysis of the prompt optical emission. With
a two-component distribution of initial Lorentz factors, we simulate the
dynamical process of the ejected shells from the central engine in the
framework of the internal shock model. The emitted radiation are decomposed
into different frequency ranges for a temporal correlation analysis between the
lightcurves in different energy bands. The resulting prompt optical and
gamma-ray emission show similar temporal profiles, both as a superposition of a
slow variability component and a fast variability component, except that the
gamma-ray lightcurve is much more variable than its optical counterpart. The
variability features in the simulated lightcurves and the strong correlation
with a time lag between the optical and gamma-ray emission are in good
agreement with the observations of GRB 080319B. Our simulations suggest that
the variations seen in the lightcurves stem from the temporal structure of the
shells injected from the central engine of gamma-ray bursts. The future high
temporal resolution observations of prompt optical emission from GRBs, e.g., by
UFFO-Pathfinder and SVOM-GWAC, provide a useful tool to investigate the central
engine activity.


title:
Formation of Nanofoam carbon and re-emergence of Superconductivity in
  compressed CaC6

abstract:
  Pressure can tune material's electronic properties and control its quantum
state, making some systems present disconnected superconducting region as
observed in iron chalcogenides and heavy fermion CeCu2Si2. For CaC6
superconductor (Tc of 11.5 K), applying pressure first Tc increases and then
suppresses and the superconductivity of this compound is eventually disappeared
at about 18 GPa. Here, we report a theoretical finding of the re-emergence of
superconductivity in heavily compressed CaC6. The predicted phase III (space
group Pmmn) with formation of carbon nanofoam is found to be stable at wide
pressure range with a Tc up to 14.7 K at 78 GPa. Diamond-like carbon structure
is adhered to the phase IV (Cmcm) for compressed CaC6 after 126 GPa, which has
bad metallic behavior, indicating again departure from superconductivity.
Re-emerged superconductivity in compressed CaC6 paves a new way to design
new-type superconductor by inserting metal into nanoporous host lattice.


title: On the Maxwell Inequalities for Bounded and Convex Domains

abstract:
  For a bounded and convex domain in three dimensions we show that the Maxwell
constants are bounded from below and above by Friedrichs' and Poincare's
constants.


title: On Maxwell's and Poincare's Constants

abstract:
  We prove that for bounded and convex domains in three dimensions, the Maxwell
constants are bounded from below and above by Friedrichs' and Poincar\'e's
constants. In other words, the second Maxwell eigenvalues lie between the
square roots of the second Neumann-Laplace and the first Dirichlet-Laplace
eigenvalue.


title: Spectral Generalized Multi-Dimensional Scaling

abstract:
  Multidimensional scaling (MDS) is a family of methods that embed a given set
of points into a simple, usually flat, domain. The points are assumed to be
sampled from some metric space, and the mapping attempts to preserve the
distances between each pair of points in the set. Distances in the target space
can be computed analytically in this setting. Generalized MDS is an extension
that allows mapping one metric space into another, that is, multidimensional
scaling into target spaces in which distances are evaluated numerically rather
than analytically. Here, we propose an efficient approach for computing such
mappings between surfaces based on their natural spectral decomposition, where
the surfaces are treated as sampled metric-spaces. The resulting spectral-GMDS
procedure enables efficient embedding by implicitly incorporating smoothness of
the mapping into the problem, thereby substantially reducing the complexity
involved in its solution while practically overcoming its non-convex nature.
The method is compared to existing techniques that compute dense correspondence
between shapes. Numerical experiments of the proposed method demonstrate its
efficiency and accuracy compared to state-of-the-art approaches.


title: Partial $\mu-\tau$ Textures and Leptogenesis

abstract:
  Motivated by the recent results from Daya Bay, Reno and Double Chooz
Collaborations, we study the consequences of small departures from exact
$\mu-\tau$ symmetry in the neutrino sector, to accommodate a non-vanishing
value of the element $V_{e3}$ from the leptonic mixing matrix. Within the
see-saw framework, we identify simple patterns of Dirac mass matrices that lead
to approximate $\mu-\tau$ symmetric neutrino mass matrices, which are
consistent with the neutrino oscillation data and lead to non-vanishing mixing
angle $V_{e3}$ as well as precise predictions for the CP violating phases. We
also show that there is a transparent link between neutrino mixing angles and
see-saw parameters, which we further explore within the context of leptogenesis
as well as double beta decay phenomenology.


title: On relative derived categories

abstract:
  The paper is devoted to study some of the questions arises naturally in
connection to the notion of relative derived categories. In particular, we
study invariants of recollements involving relative derived categories,
generalise two results of Happel by proving the existence of AR-triangles in
Gorenstein derived categories, provide situations for which relative derived
categories with respect to Gorenstein projective and Gorenstein injective
modules are equivalent and finally study relations between the Gorenstein
derived category of a quiver and its image under a reflection functor. Some
interesting applications are provided.


title:
On a singular perturbation problem arising in the theory of Evolutionary
  Distributions

abstract:
  Evolution by Natural Selection is a process by which progeny inherit some
properties from their progenitors with small variation. These properties are
subject to Natural Selection and are called adaptive traits and carriers of the
latter are called phenotypes. The distribution of the density of phenotypes in
a population is called Evolutionary Distributions (ED). We analyze mathematical
models of the dynamics of a system of ED. Such systems are anisotropic in that
diffusion of phenotypes in each population (equation) remains positive in the
directions of their own adaptive space and vanishes in the directions of the
other's adaptive space. We prove that solutions to such systems exist in a
sense weaker than the usual. We develop an algorithm for numerical solutions of
such systems. Finally, we conduct numerical experiments---with a model in which
populations compete---that allow us to observe salient attributes of a specific
system of ED.


title: Neighborhood filters and the decreasing rearrangement

abstract:
  Nonlocal filters are simple and powerful techniques for image denoising. In
this paper, we give new insights into the analysis of one kind of them, the
Neighborhood filter, by using a classical although not very common
transformation: the decreasing rearrangement of a function (the image).
Independently of the dimension of the image, we reformulate the Neighborhood
filter and its iterative variants as an integral operator defined in a
one-dimensional space. The simplicity of this formulation allows to perform a
detailed analysis of its properties. Among others, we prove that the filter
behaves asymptotically as a shock filter combined with a border diffusive term,
responsible for the staircaising effect and the loss of contrast.


title:
A Gemini/GMOS study of the physical conditions and kinematics of the
  blue compact dwarf galaxy Mrk 996

abstract:
  We present an integral field spectroscopic study with the Gemini Multi-Object
Spectrograph (GMOS) of the unusual blue compact dwarf (BCD) galaxy Mrk 996. We
show through velocity and dispersion maps, emission-line intensity and ratio
maps, and by a new technique of electron density limit imaging that the
ionization properties of different regions in Mrk 996 are correlated with their
kinematic properties. From the maps, we can spatially distinguish a very dense
high-ionization zone with broad lines in the nuclear region, and a less dense
low-ionization zone with narrow lines in the circumnuclear region. Four
kinematically distinct systems of lines are identified in the integrated
spectrum of Mrk 996, suggesting stellar wind outflows from a population of
Wolf-Rayet (WR) stars in the nuclear region, superposed on an underlying
rotation pattern. From the intensities of the blue and red bumps, we derive a
population of $\sim$473 late nitrogen (WNL) stars and $\sim$98 early carbon
(WCE) stars in the nucleus of Mrk 996, resulting in a high N(WR)/N(O+WR) of
0.19. We derive, for the outer narrow-line region, an oxygen abundance
12+log(O/H)=7.94$\pm$0.30 ($\sim$ 0.2 Z$_\odot$) by using the direct T$_e$
method derived from the detected narrow [OIII]$\lambda$4363 line. The nucleus
of Mrk 996 is, however, nitrogen-enhanced by a factor of $\sim$20, in agreement
with previous CLOUDY modeling. This nitrogen enhancement is probably due to
nitrogen-enriched WR ejecta, but also to enhanced nitrogen line emission in a
high-density environment. Although we have made use here of two new methods -
Principal Component Analysis (PCA) tomography and a method for mapping low- and
high-density clouds - to analyze our data, new methodology is needed to further
exploit the wealth of information.


title: Magnetic moments of odd-odd spherical nuclei

abstract:
  Magnetic moments of more than one hundred odd-odd spherical nuclei in ground
and excited states are calculated within the self-consistent TFFS based on the
EDF method by Fayans {\it et al}. We limit ourselves to nuclei with a neutron
and a proton particle (hole) added to the magic or semimagic core. A simple
model of no interaction between the odd nucleons is used. In most the cases we
analyzed, a good agreement with the experimental data is obtained. Several
cases are considered where this simple model does not work and it is necessary
to go beyond. The unknown values of magnetic moments of many unstable odd and
odd-odd nuclei are predicted including sixty values for excited odd-odd nuclei.


title: Local solvability and turning for the inhomogeneous Muskat problem

abstract:
  In this work we study the evolution of the free boundary between two
different fluids in a porous medium where the permeability is a two dimensional
step function. The medium can fill the whole plane $\mathbb{R}^2$ or a bounded
strip $S=\mathbb{R}\times(-\pi/2,\pi/2)$. The system is in the stable regime if
the denser fluid is below the lighter one. First, we show local existence in
Sobolev spaces by means of energy method when the system is in the stable
regime. Then we prove the existence of curves such that they start in the
stable regime and in finite time they reach the unstable one. This change of
regime (turning) was first proven in \cite{ccfgl} for the homogeneus Muskat
problem with infinite depth.


title:
Particle in a self-dual dyon background: hidden free nature, and exotic
  superconformal symmetry

abstract:
  We show that a non-relativistic particle in a combined field of a magnetic
monopole and 1/r^2 potential reveals a hidden, partially free dynamics when the
strength of the central potential and the charge-monopole coupling constant are
mutually fitted to each other. In this case the system admits both a conserved
Laplace-Runge-Lenz vector and a dynamical conformal symmetry. The
supersymmetrically extended system corresponds then to a background of a
self-dual or anti-self-dual dyon. It is described by a quadratically extended
Lie superalgebra D(2,1;alpha) with alpha=1/2, in which the bosonic set of
generators is enlarged by a generalized Laplace-Runge-Lenz vector and its
dynamical integral counterpart related to Galilei symmetry, as well as by the
chiral Z_2-grading operator. The odd part of the nonlinear superalgebra
comprises a complete set of 24=2 x 3 x 4 fermionic generators. Here a usual
duplication comes from the Z_2-grading structure, the second factor can be
associated with a triad of scalar integrals --- the Hamiltonian, the generator
of special conformal transformations and the squared total angular momentum
vector, while the quadruplication is generated by a chiral spin vector integral
which exits due to the (anti)-self-dual nature of the electromagnetic
background.


title: Reduction of Markov chains with two-time-scale state transitions

abstract:
  In this paper, we consider a general class of two-time-scale Markov chains
whose transition rate matrix depends on a parameter $\lambda>0$. We assume that
some transition rates of the Markov chain will tend to infinity as
$\lambda\rightarrow\infty$. We divide the state space of the Markov chain $X$
into a fast state space and a slow state space and define a reduced chain $Y$
on the slow state space. Our main result is that the distribution of the
original chain $X$ will converge in total variation distance to that of the
reduced chain $Y$ uniformly in time $t$ as $\lambda\rightarrow\infty$.


title: Phonon-Mediated Decay of Singlet-Triplet Qubits in Double Quantum Dots

abstract:
  We study theoretically the phonon-induced relaxation ($T_1$) and decoherence
times ($T_2$) of singlet-triplet qubits in lateral GaAs double quantum dots
(DQDs). When the DQD is biased, Pauli exclusion enables strong dephasing via
two-phonon processes. This mechanism requires neither hyperfine nor spin-orbit
interaction and yields $T_2 \ll T_1$, in contrast to previous calculations of
phonon-limited lifetimes. When the DQD is unbiased, we find $T_2 \simeq 2 T_1$
and much longer lifetimes than in the biased DQD. For typical setups, the
decoherence and relaxation rates due to one-phonon processes are proportional
to the temperature $T$, whereas the rates due to two-phonon processes reveal a
transition from $T^2$ to higher powers as $T$ is decreased. Remarkably, both
$T_1$ and $T_2$ exhibit a maximum when the external magnetic field is applied
along a certain axis within the plane of the two-dimensional electron gas. We
compare our results with recent experiments and analyze the dependence of $T_1$
and $T_2$ on system properties such as the detuning, the spin-orbit parameters,
the hyperfine coupling, and the orientation of the DQD and the applied magnetic
field with respect to the main crystallographic axes.


title: The Muon (g-2) Theory Value: Present and Future

abstract:
  This White Paper briefly reviews the present status of the muon (g-2)
Standard-Model prediction. This value results in a 3 - 4 standard-deviation
difference with the experimental result from Brookhaven E821. The present
experimental uncertainty is $\pm 63 \times 10^{-11}$ (0.54~ppm), and the
Standard-Model uncertainty is $\simeq \pm 49 \times 10^{-11}$. Fermilab
experiment E989 has the goal to reduce the experimental error to $\pm 16 \times
10^{-11}$. Improvements in the Standard-Model value, which should be achieved
between now and when the first results from Fermilab E989 could be available,
should lead to a Standard-Model uncertainty of $\sim \,\pm 35 \times 10^{-11}$.
These improvements would halve the uncertainty on the difference between
experiment and theory, and should clarify whether the current difference points
toward New Physics, or to a statistical fluctuation. At present, the (g-2)
result is arguably the most compelling indicator of physics beyond the Standard
Model and, at the very least, it represents a major constraint for speculative
new theories such as supersymmetry, dark gauge bosons or extra dimensions.


title: Semi-discrete semi-linear parabolic SPDEs

abstract:
  Consider an infinite system \[\partial_tu_t(x)=(\mathscr{L}u_t)(x)+
\sigma\bigl(u_t(x)\bigr)\partial_tB_t(x)\] of interacting It\^{o} diffusions,
started at a nonnegative deterministic bounded initial profile. We study local
and global features of the solution under standard regularity assumptions on
the nonlinearity $\sigma$. We will show that, locally in time, the solution
behaves as a collection of independent diffusions. We prove also that the $k$th
moment Lyapunov exponent is frequently of sharp order $k^2$, in contrast to the
continuous-space stochastic heat equation whose $k$th moment Lyapunov exponent
can be of sharp order $k^3$. When the underlying walk is transient and the
noise level is sufficiently low, we prove also that the solution is a.s.
uniformly dissipative provided that the initial profile is in $\ell^1(\mathbf
{Z}^d)$.


title: Modulation and Robustness of Endogenous Neuronal Spiking

abstract:
  Neuronal spiking exhibits an exquisite combination of modulation and
robustness properties, rarely matched in artificial systems. We exploit the
particular interconnection structure of conductance based models to investigate
this remarkable property. We find that much of neuronal modulation and
robustness can be explained by separating the total transmembrane current into
three different components corresponding to the three time scales of neuronal
bursting. Each equivalent current aggregates many ionic contributions into an
equivalent voltage-dependent conductance, which defines a key modulation
parameter. Plugging those equivalent feedback gains in a minimal abstract model
recovers many experimental modulation scenarii as modulatory paths in
elementary two-parameter charts. Likewise, robustness owes to the many possible
physiological realizations of a same equivalent conductance, highlighting the
role of equivalent conductances as prominent targets for neuromodulation and
intrinsic homeostasis.


title: A Large Scale Structure at Redshift 1.71 in the Lockman Hole

abstract:
  We previously identified LH146, a diffuse X-ray source in the Lockman Hole,
as a galaxy cluster at redshift 1.753. The redshift was based on one
spectroscopic value, buttressed by seven additional photometric redshifts. We
here confirm the previous spectroscopic redshift and present concordant
spectroscopic redshifts for an additional eight galaxies. The average of these
nine redshifts is 1.714 +/- 0.012 (error on mean). Scrutiny of the galaxy
distribution in redshift and the plane of the sky shows that there are two
concentrations of galaxies near the X-ray source. In addition there are three
diffuse X-ray sources spread along the axis connecting the galaxy
concentrations. LH146 is one of these three and lies approximately at the
center of the two galaxy concentrations and the outer two diffuse X-ray
sources. We thus conclude that LH146 is at the redshift initially reported but
it is not a single virialized galaxy cluster as previously assumed. Rather it
appears to mark the approximate center of a larger region containing more
objects. For brevity we term all these objects and their alignments as large
scale structure. The exact nature of LH146 itself remains unclear.


title: Calabi's diastasis as interface entropy

abstract:
  We show that the entropy of certain conformal interfaces between $N=(2,2)$
sigma models that belong to the same moduli space, has a natural geometric
interpretation in the large volume limit as Calabi's diastasis function. This
is an extension of the well-known relation between the quantum K\"ahler
potential and the overlap of canonical Ramond-Ramond ground states in $N=(2,2)$
models.


title:
Cycle symmetry, limit theorems, and fluctuation theorems for diffusion
  processes on the circle

abstract:
  Cyclic structure and dynamics are of great interest in both the fields of
stochastic processes and nonequilibrium statistical physics. In this paper, we
find a new symmetry of the Brownian motion named as the quasi-time-reversal
invariance. It turns out that such an invariance of the Brownian motion is the
key to prove the cycle symmetry for diffusion processes on the circle, which
says that the distributions of the forming times of the forward and backward
cycles, given that the corresponding cycle is formed earlier than the other,
are exactly the same. With the aid of the cycle symmetry, we prove the strong
law of large numbers, functional central limit theorem, and large deviation
principle for the sample circulations and net circulations of diffusion
processes on the circle. The cycle symmetry is further applied to obtain
various types of fluctuation theorems for the sample circulations, net
circulation, and entropy production rate.


title: Ground state solution of a nonlocal boundary-value problem

abstract:
  In this paper, we apply the method of the Nehari manifold to study the
Kirchhoff type equation \begin{equation*} -\Big(a+b\int_\Omega|\nabla
u|^2dx\Big)\Delta u=f(x,u) \end{equation*} submitted to Dirichlet boundary
conditions. Under a general $4-$superlinear condition on the nonlinearity $f$,
we prove the existence of a ground state solution; that is a nontrivial
solution which has least energy among the set of nontrivial solutions. In case
which $f$ is odd with respect to the second variable, we also obtain the
existence of infinitely many solutions. Under our assumptions the Nehari
manifold does not need to be of class $\mathcal{C}^1$.


title:
Rigorous Numerical Verification of Uniqueness and Smoothness in a
  Surface Growth Model

abstract:
  Based on numerical data and a-posteriori analysis we verify rigorously the
uniqueness and smoothness of global solutions to a scalar surface growth model
with striking similarities to the 3D Navier--Stokes equations, for certain
initial data for which analytical approaches fail. The key point is the
derivation of a scalar ODE controlling the norm of the solution, whose
coefficients depend on the numerical data. Instead of solving this ODE
explicitly, we explore three different numerical methods that provide rigorous
upper bounds for its solution


title:
Signatures of infall motions in the images of the molecular emission of
  G31 HMC

abstract:
  Although gravitational collapse is supposed to play an essential role in the
star formation process, infall motions have been always elusive to detect. So
far, only a few observational signatures have been commonly used to claim for
the presence of infall. Often these features consist in either
"blue-asymmetries" or absorption at red-shifted velocities (e.g., inverse
P-Cygni profiles). Both signatures are based only on the shape of the line
profile and they do not guarantee by themselves the presence of dominant infall
motions. More robust "mapping signatures" can be obtained from images that
angularly resolve the infalling gas. Here we present VLA observations of the
ammonia inversion transitions (2,2), (3,3), (4,4), (5,5), and (6,6) towards the
hot molecular core (HMC) near G31.41+0.31 that show the signatures of
protostellar infall theoretically predicted by Anglada et al. (1991). The
intensity of the ammonia emission is compact and sharply increases towards the
centre in the blue-shifted velocity channel maps, while it shows a more
flattened distribution in the red-shifted velocity channels. Additionally, the
emission becomes more compact with increasing (relative) velocity for both red
and blue-shifted channels. We introduce a new infall signature, the "central
blue spot", easily identifiable in the first-order moment maps. We show that
rotation produces an additional, independent signature, making the distribution
of the emission in the channel maps asymmetric with respect to the central
position, but without masking the infall signatures. All these mapping
signatures, which are identified here for the first time, are present in the
observed ammonia transitions of G31 HMC.


title:
Numerical Solution of Stochastic Partial Differential Equations with
  Correlated Noise

abstract:
  In this paper we investigate the numerical solution of stochastic partial
differential equations (SPDEs) for a wider class of stochastic equations. We
focus on non-diagonal colored noise instead of the usual space-time white
noise. By applying a spectral Galerkin method for spatial discretization and a
numerical scheme in time introduced by Jentzen $\&$ Kloeden, we obtain the rate
of path-wise convergence in the uniform topology. The main assumptions are
either uniform bounds on the spectral Galerkin approximation or uniform bounds
on the numerical data. Numerical examples illustrate the theoretically
predicted convergence rate.


title:
Report of the Snowmass 2013 Computing Frontier Working Group on
  Distributed Computing and Facility Infrastructures

abstract:
  This is the report of the Snowmass 2013 Computing Frontier Working Group on
Distributed Computing and Facility Infrastructures.

categories: physics.comp-ph cs.DC hep-ex hep-lat hep-ph


title:
Spectral measures associated with the factorization of the Lebesgue
  measure on a set via convolution

abstract:
  Let $Q$ be a fundamental domain of some full-rank lattice in ${\Bbb R}^d$ and
let $\mu$ and $\nu$ be two positive Borel measures on ${\Bbb R}^d$ such that
the convolution $\mu\ast\nu$ is a multiple of $\chi_Q$. We consider the problem
as to whether or not both measures must be spectral (i.e. each of their
respective associated $L^2$ space admits an orthogonal basis of exponentials)
and we show that this is the case when $Q = [0,1]^d$. This theorem yields a
large class of examples of spectral measures which are either absolutely
continuous, singularly continuous or purely discrete spectral measures. In
addition, we propose a generalized Fuglede's conjecture for spectral measures
on ${\Bbb R}^1$ and we show that it implies the classical Fuglede's conjecture
on ${\Bbb R}^1$.


title: On Interval Non-Edge-Colorable Eulerian Multigraphs

abstract:
  An edge-coloring of a multigraph $G$ with colors $1,\ldots,t$ is called an
interval $t$-coloring if all colors are used, and the colors of edges incident
to any vertex of $G$ are distinct and form an interval of integers. In this
note, we show that all Eulerian multigraphs with an odd number of edges have no
interval coloring. We also give some methods for constructing of interval
non-edge-colorable Eulerian multigraphs.


title: On real tropical bases and real tropical discriminants

abstract:
  We explore the concept of real tropical basis of an ideal in the field of
real Puiseux series. We show explicit tropical bases of zero-dimensional real
radical ideals, linear ideals and hypersurfaces coming from combinatorial
patchworking. But we also show that there exist real radical ideals that do not
admit a tropical basis. As an application, we show how to compute the set of
singular points of a real tropical hypersurface. i.e. we compute the real
tropical discriminant.


title:
Equilibration and prethermalization in the Bose-Hubbard and
  Fermi-Hubbard models

abstract:
  We study the Bose and Fermi Hubbard model in the (formal) limit of large
coordination numbers $Z\gg1$. Via an expansion into powers of $1/Z$, we
establish a hierarchy of correlations which facilitates an approximate
analytical derivation of the time-evolution of the reduced density matrices for
one and two sites etc. With this method, we study the quantum dynamics
(starting in the ground state) after a quantum quench, i.e., after suddenly
switching the tunneling rate $J$ from zero to a finite value, which is still in
the Mott regime. We find that the reduced density matrices approach a (quasi)
equilibrium state after some time. For one lattice site, this state can be
described by a thermal state (within the accuracy of our approximation).
However, the (quasi) equilibrium state of the reduced density matrices for two
sites including the correlations cannot be described by a thermal state. Thus,
real thermalization (if it occurs) should take much longer time. This behavior
has already been observed in other scenarios and is sometimes called
``pre-thermalization.'' Finally, we compare our results to numerical
simulations for finite lattices in one and two dimensions and find qualitative
agreement.


title: A first principles investigated optical spectra of oxizided graphene

abstract:
  The electronic and optical properties of mono, di, tri, and tetravacancies in
graphene are studied in comparison to each other, using density functional
theory. In addition, oxidized monovacancies are considered for different oxygen
concentrations. Pristine graphene is found to be more absorptive than any
defect configuration at low energy. We demonstrate characteristic differences
in the optical spectra of the various defects for energies up to 3 eV. This
makes it possible to quantify by optical spectroscopy the ratios of the defect
species present in a sample.


title: A new technique for direct investigation of dark matter

abstract:
  The MOSCAB experiment (Materia OSCura A Bolle) uses a new technique for Dark
Matter search. The Geyser technique is applied to the construction of a
prototype detector with a mass of 0.5 kg and the encouraging results are
reported here; an accent is placed on a big detector of 40 kg in construction
at the Milano-Bicocca University and INFN.


title:
A generalized action for $\left( 2 + 1 \right)$-dimensional
  Chern--Simons gravity

abstract:
  We show that the so-called semi-simple extended Poincar\'{e} (SSEP) algebra
in $D$ dimensions can be obtained from the anti-de~Sitter algebra
$\mathfrak{so} \left( D-1,2 \right)$ by means of the $S$-expansion procedure
with an appropriate semigroup $S$. A general prescription is given for
computing Casimir operators for $S$-expanded algebras, and the method is
exemplified for the SSEP algebra. The $S$-expansion method also allows us to
extract the corresponding invariant tensor for the SSEP algebra, which is a key
ingredient in the construction of a generalized action for Chern--Simons
gravity in $2+1$ dimensions.


title:
Modeling stochastic phenotype switching and bet-hedging in bacteria:
  stochastic nonlinear dynamics and critical state identification

abstract:
  Fluctuating environments pose tremendous challenges to bacterial populations.
It is observed in numerous bacterial species that individual cells can
stochastically switch among multiple phenotypes for the population to survive
in rapidly changing environments. This kind of phenotypic heterogeneity with
stochastic phenotype switching is generally understood to be an adaptive
bet-hedging strategy. Mathematical models are essential to gain a deeper
insight into the principle behind bet-hedging and the pattern behind
experimental data. Traditional deterministic models cannot provide a correct
description of stochastic phenotype switching and bet-hedging, and traditional
Markov chain models at the cellular level fail to explain their underlying
molecular mechanisms. In this paper, we propose a nonlinear stochastic model of
multistable bacterial systems at the molecular level. It turns out that our
model not only provides a clear description of stochastic phenotype switching
and bet-hedging within isogenic bacterial populations, but also provides a
deeper insight into the analysis of multidimensional experimental data.
Moreover, we use some deep mathematical theories to show that our stochastic
model and traditional Markov chain models are essentially consistent and
reflect the dynamic behavior of the bacterial system at two different time
scales. In addition, we provide a quantitative characterization of the critical
state of multistable bacterial systems and develop an effective data-driven
method to identify the critical state without resorting to specific
mathematical models.


title: Microrheology measurements with a hanging-fiber AFM probe

abstract:
  A method to measure the viscosity of liquids at microscales is presented. It
uses a thin glass fiber fixed on the tip of the cantilever of an extremely low
noise Atomic Force Microscope (AFM), which accurately measures the cantilever
{deflection}. When the fiber is dipped into the liquid the dissipation of the
cantilever-fiber system increases. This dissipation, linked to the liquid
viscosity, is computed from the power spectral density of the thermal
fluctuations of the cantilever {deflection}. The {high sensitivity of the AFM}
allows us to show the existence and to develop a model of the coupling between
the dynamics of the fiber and that of the cantilever. This model {accurately}
fits the experimental data. The advantages and draw-backs of the method are
discussed


title: The leaves of the Fatou set accumulate on the leaves of the Julia set

abstract:
  In 2001 E. Ghys, X. Gomez-Mont and J. Saludes defined the Fatou and Julia
components of transversely holomorphic foliations on compact manifolds. It is a
partition of the manifold in two saturated sets: the Fatou set which represents
the non-chaotic part of the foliation and its complementary, the Julia set.
Using the Brownian motion transverse to the foliation, it is proved in this
paper that, if the foliation is taut and if F is a wandering component of the
Fatou set, then almost every point of the topological boundary of F (almost for
any harmonic measure on the boundary) is a limit point of each leaf of F.


title: The poset of posets

abstract:
  Let X be a finite set. This paper describes some topological and
combinatorial properties of the poset \Omega_X of order relations on X. In
particular, the homotopy type of all the intervals in \Omega_X is precisely
determined, and the M\"obius function of \Omega_X is computed.


title: Re-testing the JET-X Flight Module No. 2 at the PANTER facility

abstract:
  The Joint European X-ray Telescope (JET-X) was the core instrument of the
Russian Spectrum-X-gamma space observatory. It consisted of two identical soft
X-ray (0.3 - 10 keV) telescopes with focusing optical modules having a measured
angular resolution of nearly 15 arcsec. Soon after the payload completion, the
mission was cancelled and the two optical flight modules (FM) were brought to
the Brera Astronomical Observatory where they had been manufactured. After 16
years of storage, we have utilized the JET-X FM2 to test at the PANTER X-ray
facility a prototype of a novel X-ray polarimetric telescope, using a Gas Pixel
Detector (GPD) with polarimetric capabilities in the focal plane of the FM2.
The GPD was developed by a collaboration between INFN-Pisa and INAF-IAPS. In
the first phase of the test campaign, we have re-tested the FM2 at PANTER to
have an up-to-date characterization in terms of angular resolution and
effective area, while in the second part of the test the GPD has been placed in
the focal plane of the FM2. In this paper we report the results of the tests of
the sole FM2, using an unpolarized X-ray source, comparing the results with the
calibration done in 1996.


title: Non ultracontractive heat kernel bounds by Lyapunov conditions

abstract:
  Nash and Sobolev inequalities are known to be equivalent to ultracontractive
properties of heat-like Markov semigroups, hence to uniform on-diagonal bounds
on their kernel densities. In non ultracontractive settings, such bounds can
not hold, and (necessarily weaker, non uniform) bounds on the semigroups can be
derived by means of weighted Nash (or super-Poincar\'e) inequalities. The
purpose of this note is to show how to check these weighted Nash inequalities
in concrete examples, in a very simple and general manner. We also deduce
off-diagonal bounds for the Markov kernels of the semigroups, refining E. B.
Davies' original argument.


title:
Review of the Use of Electroencephalography as an Evaluation Method for
  Human-Computer Interaction

abstract:
  Evaluating human-computer interaction is essential as a broadening population
uses machines, sometimes in sensitive contexts. However, traditional evaluation
methods may fail to combine real-time measures, an "objective" approach and
data contextualization. In this review we look at how adding neuroimaging
techniques can respond to such needs. We focus on electroencephalography (EEG),
as it could be handled effectively during a dedicated evaluation phase. We
identify workload, attention, vigilance, fatigue, error recognition, emotions,
engagement, flow and immersion as being recognizable by EEG. We find that
workload, attention and emotions assessments would benefit the most from EEG.
Moreover, we advocate to study further error recognition through neuroimaging
to enhance usability and increase user experience.


title:
Global stability of stretched jets: conditions for the generation of
  monodisperse micro-emulsions using coflows

abstract:
  In this paper we reveal the physics underlying the conditions needed for the
generation of emulsions composed of uniformly sized drops of micrometric or
submicrometric diameters when two immiscible streams flow in parallel under the
so-called tip streaming regime after Suryo & Basaran (2006). Indeed, when
inertial effects in both liquid streams are negligible, the inner to outer
flow-rate and viscosity ratios are small enough and the capillary number is
above an experimentally determined threshold which is predicted by our
theoretical results with small relative errors, a steady micron-sized jet is
issued from the apex of a conical drop. Under these conditions, the jet
disintegrates into drops with a very well defined mean diameter, giving rise to
a monodisperse micro-emulsion. Here, we demonstrate that the regime in which
uniformly-sized drops are produced corresponds to values of the capillary
number for which the cone-jet system is globally stable. Interestingly enough,
our general stability theory reveals that liquid jets with a cone-jet structure
are much more stable than their cylindrical counterparts thanks, mostly, to a
capillary stabilization mechanism described here for the first time. Our
findings also limit the validity of the type of stability analysis based on the
common parallel flow assumption to only those situations in which the liquid
jet diameter is almost constant.


title: Fusion Product Structure of Demazure Modules

abstract:
  Let g be a finite-dimensional complex simple Lie algebra. Fix a non-negative
integer l, we consider the set of dominant weights {\lambda} of g such that
l{\Lambda}_0+{\lambda} is a dominant weight for the corresponding untwisted
affine Kac-Moody algebra. For these special family of dominant weights, we show
that the fusion product of an irreducible g-module V({\lambda}) and a finite
number of special family of g-stable Demazure modules of level l (considered in
[15] and [16]), for the current algebra g[t] associated to g, again turns out
to be a Demazure module. This fact is closely related with several important
conjectures. We use this result to construct the g[t]-module structure of the
irreducible module V(l{\Lambda}_0 + {\lambda}) as a semi-infinite fusion
product of finite dimensional g[t]-modules as conjectured in [16]. As a second
application we give further evidence to the conjecture on the generalization of
Schur positivity (see [7]).


title: On uncountable hypersimple unidimensional theories

abstract:
  We extend a dichotomy between 1-basedness and supersimplicity proved in a
previous paper. The generalization we get is to arbitrary language, with no
restrictions on the topology (we do not demand type-definabilty of the open set
in the definition of essential 1-basedness). We conclude that every (possibly
uncountable) hypersimple unidimensional theory that is not s-essentially
1-based by means of the forking topology is supersimple. We also obtain a
strong version of the above dichotomy in the case where the language is
countable.


title:
Phonon and Thermal Properties of Exfoliated Tantalum Diselenide Thin
  Films

abstract:
  We report on the phonon and thermal properties of thin films of tantalum
diselenide (2H-TaSe2) obtained via the graphene-like mechanical exfoliation of
crystals grown by chemical vapor transport. The ratio of the intensities of the
Raman peak from the Si substrate and the E2g peak of TaSe2 presents a
convenient metric for quantifying film thickness. The temperature coefficients
for two main Raman peaks, A1g and E2g, are -0.013 and -0.0097 cm-1/oC,
respectively. The Raman optothermal measurements indicate that the room
temperature thermal conductivity in these films decreases from its bulk value
of ~16 W/mK to ~9 W/mK in 45-nm thick films. The measurement of electrical
resistivity of the field-effect devices with TaSe2 channels indicates that heat
conduction is dominated by acoustic phonons in these van der Waals films. The
scaling of thermal conductivity with the film thickness suggests that the
phonon scattering from the film boundaries is substantial despite the sharp
interfaces of the mechanically cleaved samples. These results are important for
understanding the thermal properties of thin films exfoliated from TaSe2 and
other metal dichalcogenides, as well as for evaluating self-heating effects in
devices made from such materials.


title:
New Constraints on the Escape of Ionizing Photons From Starburst
  Galaxies Using Ionization-Parameter Mapping

abstract:
  The fate of ionizing radiation in starburst galaxies is key to understanding
cosmic reionization. However, the galactic parameters on which the escape
fraction of ionizing radiation depend are not well understood.
Ionization-parameter mapping provides a simple, yet effective, way to study the
radiative transfer in starburst galaxies. We obtain emission-line ratio maps of
[SIII]/[SII] for six, nearby, dwarf starbursts: NGC 178, NGC 1482, NGC 1705,
NGC 3125, NGC 7126, and He 2-10. The narrow-band images are obtained with the
Maryland-Magellan Tunable Filter at Las Campanas Observatory. Using these data,
we previously reported the discovery of an optically thin ionization cone in
NGC 5253, and here we also discover a similar ionization cone in NGC 3125. This
latter cone has an opening angle of 40+/-5 degrees (0.4 ster), indicating that
the passageways through which ionizing radiation may travel correspond to a
small solid angle. Additionally, there are three sample galaxies that have
winds and/or superbubble activity, which should be conducive to escaping
radiation, yet they are optically thick. These results support the scenario
that an orientation bias limits our ability to directly detect escaping Lyman
continuum in many starburst galaxies. A comparison of the star-formation
properties and histories of the optically thin and thick galaxies is consistent
with the model that high escape fractions are limited to galaxies that are old
enough (> 3 Myr) for mechanical feedback to have cleared optically thin
passageways in the ISM, but young enough (< 5 Myr) that the ionizing stars are
still present.


title: Lie Infinity-Algebras from Lie Rinehart Pairs

abstract:
  We generalize the Schouten calculus of multivector fields to commutative Lie
Rinehart pairs and define a non negatively graded Lie oo-algebra on their
exterior power.


title: Joint Sparsity Recovery for Spectral Compressed Sensing

abstract:
  Compressed Sensing (CS) is an effective approach to reduce the required
number of samples for reconstructing a sparse signal in an a priori basis, but
may suffer severely from the issue of basis mismatch. In this paper we study
the problem of simultaneously recovering multiple spectrally-sparse signals
that are supported on the same frequencies lying arbitrarily on the unit
circle. We propose an atomic norm minimization problem, which can be regarded
as a continuous counterpart of the discrete CS formulation and be solved
efficiently via semidefinite programming. Through numerical experiments, we
show that the number of samples per signal may be further reduced by harnessing
the joint sparsity pattern of multiple signals.


title: On linear combinations of Chebyshev polynomials

abstract:
  We investigate an infinite sequence of polynomials of the form:
\[a_0T_{n}(x)+a_{1}T_{n-1}(x)+\cdots+a_{m}T_{n-m}(x)\] where
$(a_0,a_1,\ldots,a_m)$ is a fixed m-tuple of real numbers, $a_0,a_m\ne0$,
$T_i(x)$ are Chebyshev polynomials of the first kind, $n=m,m+1,m+2,\ldots$ Here
we analyse the structure of the set of zeros of such polynomial, depending on
$A$ and its limit points when $n$ tends to infinity. Also the expression of
envelope of the polynomial is given. An application in number theory, more
precise, in the theory of Pisot and Salem numbers is presented.


title:
Generalized multi-terminal decoherent transport: Recursive algorithms
  and applications to SASER and giant magnetoresistance

abstract:
  Decoherent transport in mesoscopic and nanoscopic systems can be formulated
in terms of the D'Amato-Pastawski (DP) model. This generalizes the
Landauer-B\"{u}ttiker picture by considering a distribution of local decoherent
processes. However, its generalization for multi-terminal setups is lacking. We
first review the original two-terminal DP model for decoherent transport. Then,
we extend it to a matrix formulation capable of dealing with multi-terminal
problems. We also introduce recursive algorithms to evaluate the Green's
functions for general banded Hamiltonians as well as local density of states,
effective conductances and voltage profiles. We finally illustrate the method
by analyzing two problems of current relevance. 1) Assessing the role of
decoherence in a model for phonon lasers (SASER). 2) Obtaining the classical
limit of Giant Magnetoresistance from a spin-dependent Hamiltonian. The
presented methods should pave the way for computationally demanding
calculations of transport through nanodevices, bridging the gap between fully
coherent quantum schemes and semiclassical ones.


title:
The Bieri-Neumann-Strebel Invariant of the Pure Symmetric Automorphisms
  of a Right-Angled Artin Group

abstract:
  We compute the BNS-invariant for the pure symmetric automorphism groups of
right-angled Artin groups. We use this calculation to show that the pure
symmetric automorphism group of a right-angled Artin group is itself not a
right-angled Artin group provided that its defining graph contains a separating
intersection of links.


title: Ultrafast nonlocal control of spontaneous emission

abstract:
  Solid-state cavity quantum electrodynamics systems will form scalable nodes
of future quantum networks, allowing the storage, processing and retrieval of
quantum bits, where a real-time control of the radiative interaction in the
cavity is required to achieve high efficiency. We demonstrate here the dynamic
molding of the vacuum field in a coupled-cavity system to achieve the ultrafast
nonlocal modulation of spontaneous emission of quantum dots in photonic crystal
cavities, on a timescale of ~200 ps, much faster than their natural radiative
lifetimes. This opens the way to the ultrafast control of semiconductor-based
cavity quantum electrodynamics systems for application in quantum interfaces
and to a new class of ultrafast lasers based on nano-photonic cavities.


title: FuSSO: Functional Shrinkage and Selection Operator

abstract:
  We present the FuSSO, a functional analogue to the LASSO, that efficiently
finds a sparse set of functional input covariates to regress a real-valued
response against. The FuSSO does so in a semi-parametric fashion, making no
parametric assumptions about the nature of input functional covariates and
assuming a linear form to the mapping of functional covariates to the response.
We provide a statistical backing for use of the FuSSO via proof of asymptotic
sparsistency under various conditions. Furthermore, we observe good results on
both synthetic and real-world data.


title: Fractions in elementary education

abstract:
  This paper is one of a series in which elementary-education practice is
analyzed by comparison with the history of mathematics, mathematical structure,
modern practice, and (occasionally) cognitive neuroscience. The primary
concerns are: Why do so many children find elementary mathematics difficult?
And, why are the ones who succeed still so poorly prepared for college material
needed for technical careers? The answer provided by conventional wisdom is
essentially that mathematics is difficult. Third-graders are not
developmentally ready for the subtlety of fractions, for instance, and even
high-performing students cannot be expected to develop the skills of
experienced users. However we will see that this is far from the whole story
and is probably wrong: elementary-education fractions are genuinely harder and
less effective than the version employed by experienced users. Experts discard
at least 90% of what is taught in schools. Our educational system is actually
counterproductive for skill development, and the reasons for this are an
important secondary concern.


title: Fast Distribution To Real Regression

abstract:
  We study the problem of distribution to real-value regression, where one aims
to regress a mapping $f$ that takes in a distribution input covariate $P\in
\mathcal{I}$ (for a non-parametric family of distributions $\mathcal{I}$) and
outputs a real-valued response $Y=f(P) + \epsilon$. This setting was recently
studied, and a "Kernel-Kernel" estimator was introduced and shown to have a
polynomial rate of convergence. However, evaluating a new prediction with the
Kernel-Kernel estimator scales as $\Omega(N)$. This causes the difficult
situation where a large amount of data may be necessary for a low estimation
risk, but the computation cost of estimation becomes infeasible when the
data-set is too large. To this end, we propose the Double-Basis estimator,
which looks to alleviate this big data problem in two ways: first, the
Double-Basis estimator is shown to have a computation complexity that is
independent of the number of of instances $N$ when evaluating new predictions
after training; secondly, the Double-Basis estimator is shown to have a fast
rate of convergence for a general class of mappings $f\in\mathcal{F}$.


title:
Critical exponents of the two dimensional Coulomb gas at the
  Berezinskii-Kosterlitz-Thouless transition

abstract:
  The two dimensional Coulomb gas is the prototypical model of statistical
mechanics displaying a special kind of phase transition, named after
Berezinskii, Kosterlitz and Thouless. Physicists and mathematicians proposed
several predictions about this system. Two of them, valid along the phase
transition curve and for small activity, are: a) the long-distance decay of the
"fractional charge" correlation is power law, with a multiplicative logarithmic
correction; b) in such a decay, the exponent of the power law, as well as the
exponent of the logarithmic correction, have a certain precise dependence upon
the charge value. In this paper we provide a proof of these two long standing
conjectures.


title:
Modulation of beta oscillations during movement initiation: modeling the
  ionic basis of a functional switch

abstract:
  We use a computational model to propose a physiological mechanism by which
transient control of beta oscillations in the indirect pathway of the basal
ganglia is orchestrated at the cellular level. Our model includes a simple and
robust mechanism by which a cellular switch (from bursting to tonic) almost
instantaneously translates into a functional gating switch (from blocking to
conducive) in an excitatory-inhibitory network. Applied to the control of beta
oscillations in the basal ganglia, the model shows the modulation of beta
activity under the action of a transient depolarization, for instance a
dopamine signal. The model predicts, by analogy to the thalamocortical circuit,
a novel gating function by which the transfer of cortical spikes through the
indirect pathway is blocked under the inhibitory drive preceding movement but
briefly released at the onset of movement execution.


title:
On the linear operation of cloned dynamical systems and its Lyapunov
  exponents

abstract:
  The cloned dynamical system theory is introduced and the Lyapunov exponents
of this system are qualitatively proven to be same as the original dynamical
system. This property indicates that these two systems have the same error
propagation speed in the phase space, and thus we can interpret the phenomenon
as why the ensemble mean method sometimes is not effective.


title:
Non-Point Invertible Transformations and Integrability of Partial
  Difference Equations

abstract:
  This article is devoted to the partial difference quad-graph equations that
can be represented in the form $\varphi (u(i+1,j),u(i+1,j+1))=\psi
(u(i,j),u(i,j+1))$, where the map $(w,z) \rightarrow (\varphi(w,z),\psi(w,z))$
is injective. The transformation $v(i,j)=\varphi (u(i,j),u(i,j+1))$ relates any
of such equations to a quad-graph equation. It is proved that this
transformation maps Darboux integrable equations of the above form into Darboux
integrable equations again and decreases the orders of the transformed
integrals by one in the $j$-direction. As an application of this fact, the
Darboux integrable equations possessing integrals of the second order in the
$j$-direction are described under an additional assumption. The transformation
also maps symmetries of the original equations into symmetries of the
transformed equations (i.e. preserves the integrability in the sense of the
symmetry approach) and acts as a difference substitution for symmetries of a
special form. The latter fact allows us to derive necessary conditions of
Darboux integrability for the equations defined in the first sentence of the
abstract.


title: Learning Gaussian Graphical Models with Observed or Latent FVSs

abstract:
  Gaussian Graphical Models (GGMs) or Gauss Markov random fields are widely
used in many applications, and the trade-off between the modeling capacity and
the efficiency of learning and inference has been an important research
problem. In this paper, we study the family of GGMs with small feedback vertex
sets (FVSs), where an FVS is a set of nodes whose removal breaks all the
cycles. Exact inference such as computing the marginal distributions and the
partition function has complexity $O(k^{2}n)$ using message-passing algorithms,
where k is the size of the FVS, and n is the total number of nodes. We propose
efficient structure learning algorithms for two cases: 1) All nodes are
observed, which is useful in modeling social or flight networks where the FVS
nodes often correspond to a small number of high-degree nodes, or hubs, while
the rest of the networks is modeled by a tree. Regardless of the maximum
degree, without knowing the full graph structure, we can exactly compute the
maximum likelihood estimate in $O(kn^2+n^2\log n)$ if the FVS is known or in
polynomial time if the FVS is unknown but has bounded size. 2) The FVS nodes
are latent variables, where structure learning is equivalent to decomposing a
inverse covariance matrix (exactly or approximately) into the sum of a
tree-structured matrix and a low-rank matrix. By incorporating efficient
inference into the learning steps, we can obtain a learning algorithm using
alternating low-rank correction with complexity $O(kn^{2}+n^{2}\log n)$ per
iteration. We also perform experiments using both synthetic data as well as
real data of flight delays to demonstrate the modeling capacity with FVSs of
various sizes.


title: A characterization of Wilson-Lerch primes

abstract:
  This note presents criteria in terms of Bernoulli numbers for a number to be
simultaneously a Wilson prime and a Lerch prime.


title: A Nanoscale Shape Memory Oxide

abstract:
  Stimulus-responsive shape memory materials have attracted tremendous research
interests recently, with much effort focused on improving their mechanical
actuation. Driven by the needs of nanoelectromechnical devices, materials with
large mechanical strain particularly at nanoscale are therefore desired. Here
we report on the discovery of a large shape memory effect in BiFeO3 at the
nanoscale. A maximum strain of up to ~14% and a large volumetric work density
can be achieved in association with a martensitic-like phase transformation.
With a single step, control of the phase transformation by thermal activation
or electric field has been reversibly achieved without the assistance of
external recovery stress. Although aspects such as hysteresis, micro-cracking
etc. have to be taken into consideration for real devices, the large shape
memory effect in this oxide surpasses most alloys and therefore demonstrates
itself as an extraordinary material for potential use in state-of-art
nano-systems.


title: Geometric Ferroelectricity in Fluoro-Perovskites

abstract:
  We used first-principles calculations to investigate the existence and origin
of the ferroelectric in- stability in the ABF3 fluoro-perovskites. We find that
many fluoro-perovskites have a ferroelectric instability in their high symmetry
cubic structure, which is of similar amplitude to that commonly found in oxide
perovskites. In contrast to the oxides, however, the fluorides have nominal
Born effective charges, indicating a different mechanism for the instability.
We show that the instability originates from ionic size effects, and is
therefore in most cases largely insensitive to pressure and strain, again in
contrast to the oxide perovskites. An exception is NaMnF3, where coherent
epitaxial strain matching to a substrate with equal in-plane lattice constants
destabilizes the bulk Pnma structure leading to a ferroelectric, and indeed
multiferroic, ground state with an unusual polarization/strain response.


title: A Study of Al-Mn Transition Edge Sensor Engineering for Stability

abstract:
  The stability of Al-Mn transition edge sensor (TES) bolometers is studied as
we vary the engineered TES transition, heat capacity, and/or coupling between
the heat capacity and TES. We present thermal structure measurements of each of
the 39 designs tested. The data is accurately fit by a two-body bolometer
model, which allows us to extract the basic TES parameters that affect device
stability. We conclude that parameters affecting device stability can be
engineered for optimal device operation, and present the model parameters
extracted for the different TES designs.


title:
$\Phi$-Harmonic Functions on Discrete Groups and First
  $\ell^\Phi$-Cohomology

abstract:
  We study the first cohomology groups of a countable discrete group $G$ with
coefficients in a $G$-module $\ell^\Phi(G)$, where $\Phi$ is an $N$-function of
class $\Delta_2(0)\cap \nabla_2(0)$. In development of ideas of Puls and
Martin--Valette, for a finitely generated group $G$, we introduce the discrete
$\Phi$-Laplacian and prove a theorem on the decomposition of the space of
$\Phi$-Dirichlet finite functions into the direct sum of the spaces of
$\Phi$-harmonic functions and $\ell^\Phi(G)$ (with an appropriate
factorization). We also prove that if a finitely generated group $G$ has a
finitely generated infinite amenable subgroup with infinite centralizer then
$\overline{H}^{1}(G,\ell^{\Phi}(G)) = 0$. In conclusion, we show the triviality
of the first cohomology group for a wreath product of two groups one of which
is nonamenable.


title:
Bifurcations of relative equilibria near zero momentum in Hamiltonian
  systems with spherical symmetry

abstract:
  For Hamiltonian systems with spherical symmetry there is a marked difference
between zero and non-zero momentum values, and amongst all relative equilibria
with zero momentum there is a marked difference between those of zero and those
of non-zero angular velocity. We use techniques from singularity theory to
study the family of relative equilibria that arise as a symmetric Hamiltonian
which has a group orbit of equilibria with zero momentum is perturbed so that
the zero-momentum relative equilibrium are no longer equilibria. We also
analyze the stability of these perturbed relative equilibria, and consider an
application to satellites controlled by means of rotors.


title:
A measurement of the total cross section of $\sigma_{Zh}$ at a future
  $e^{+}e^{-}$ collider using the hadronic decay mode of $Z$

abstract:
  A feasibility to use the hadronic decay mode of $Z$ for the model independant
measurement of the total cross section of Higgs-strahlung process
$(\sigma_{Zh})$ at a future $e^+e^-$ collider was studied. For the recoil mass
measurement from hadronic decay of $Z$, a simple cut based analysis was applied
on samples produced by the ILD full detector simulation at $\sqrt{s}=350$ GeV
and 500 GeV using the ILC beam parameters. At $350$ GeV, a bump in the recoil
mass distribution was reconstructed, and $\Delta\sigma_{Zh}/\sigma_{Zh}$ = 3.4%
was obtained assuming 165 fb$^{-1}$ data with $e^-(e^+)$ beam polarization of
-80%(+30%) and +80%(-30%), respectively. At $500$ GeV, clear Higgs boson peak
in the recoil mass distribution was not seen, however, from the excess of the
events, $\Delta\sigma_{Zh}/\sigma_{Zh}=3.9%$ was obtained assuming 500
fb$^{-1}$ data with $e^-(e^+)$ beam polarization of -80%(+30%).


title:
Off-axis irradiation and the polarization of broad emission lines in
  active galactic nuclei

abstract:
  The STOKES Monte Carlo radiative transfer code has been extended to model the
velocity dependence of the polarization of emission lines. We use STOKES to
present improved modelling of the velocity-dependent polarization of broad
emission lines in active galactic nuclei. We confirm that off-axis continuum
emission can produce observed velocity dependencies of both the degree and
position angle of polarization. The characteristic features are a dip in the
percentage polarization and an S-shaped swing in the position angle of the
polarization across the line profile. Some differences between our STOKES
results and previous modelling of polarization due to off-axis emission are
noted. In particular we find that the presence of an offset between the maximum
in line flux and the dip in the percentage of polarization or the central
velocity of the swing in position angle does not necessarily imply that the
scattering material is moving radially. Our model is an alternative scenario to
the equatorial scattering disk described by Smith et al. (2005). We discuss
strategies to discriminate between both interpretations and to constrain their
relative contributions to the observed velocity-resolved line and polarization.


title:
Pairing and the phase diagram of the normal coherence length
  $\xi_N(T,x)$ above $T_c$ of $La_{2-x}Sr_xCuO_4$ thin films probed by the
  Josephson effect

abstract:
  Critical currents $I_c$ were measured in Superconducting - normal -
superconducting SNS c-axis junctions, where S was optimally doped
$YBa_2Cu_3O_{7-\delta}$ below $T_c$ (90 K) and N was $La_{2-x}Sr_xCuO_4$ above
its $T_c$ ($<$25 K) but in the pseudogap regime. $I_c$ was measured versus
temperature T in junctions with various N-barrier thicknesses $d$ and doping
levels $x$. From the proximity effect relation $I_c(T)\propto
exp[-d/\xi_N(T)]$, the normal coherence length $\xi_N(T)$ of N was extracted
and plotted versus T. Besides finding a long range proximity effect as reported
also by others, we found a crossing at about 55 K above which
$\xi_N(x=0.1)>\xi_N(x=0.18)]$. This unexpected result where junctions with
lower carrier density in the barrier have higher conductance, is attributed to
the presence of pre-formed pairs in the pseudogap regime of the cuprate
barrier. Our data yields a new phase diagram of $\xi_N(T,x)$ whose contours of
constant $\xi_N$ follow the trend of the superconducting dome of
$La_{2-x}Sr_xCuO_4$ above its $T_c$, with $\xi_N$ enhancement in the underdoped
regime above 55 K.


title: The $B^*B\pi$ coupling with relativistic heavy quarks

abstract:
  We report on a calculation of the $B^*B\pi$ coupling in lattice QCD. The
strong matrix element $\langle B \pi | B^*\rangle$ is directly related to the
leading order low-energy constant in heavy meson chiral perturbation theory
(HM$\chi$PT) for $B$-mesons. We carry out our calculation directly at the
$b$-quark mass using a non-perturbatively tuned clover action that controls
discretisation effects of order $|\vec{p}a|$ and $(ma)^n$ for all $n$. Our
analysis is performed on RBC/UKQCD gauge configurations using domain wall
fermions and the Iwasaki gauge action at two lattice spacings of
$a^{-1}=1.73(3)$ GeV, $a^{-1}=2.28(3)$ GeV, and unitary pion masses down to 290
MeV. We achieve good statistical precision and control all systematic
uncertainties, giving a final result for the HM$\chi$PT coupling $g_b =
0.569(48)_{stat}(59)_{sys}$ in the continuum and at the physical light-quark
masses. This is the first calculation performed directly at the physical
$b$-quark mass and lies in the region one would expect from carrying out an
interpolation between previous results at the charm mass and at the static
point.


title:
Semantic Sort: A Supervised Approach to Personalized Semantic
  Relatedness

abstract:
  We propose and study a novel supervised approach to learning statistical
semantic relatedness models from subjectively annotated training examples. The
proposed semantic model consists of parameterized co-occurrence statistics
associated with textual units of a large background knowledge corpus. We
present an efficient algorithm for learning such semantic models from a
training sample of relatedness preferences. Our method is corpus independent
and can essentially rely on any sufficiently large (unstructured) collection of
coherent texts. Moreover, the approach facilitates the fitting of semantic
models for specific users or groups of users. We present the results of
extensive range of experiments from small to large scale, indicating that the
proposed method is effective and competitive with the state-of-the-art.