1,325 research outputs found
Proton scalar dipole polarizabilities from real Compton scattering data, using fixed-t subtracted dispersion relations and the bootstrap method
We perform a fit of the real Compton scattering (RCS) data below
pion-production threshold to extract the electric () and magnetic
() static scalar dipole polarizabilities of the proton, using
fixed- subtracted dispersion relations and a bootstrap-based fitting
technique. The bootstrap method provides a convenient tool to include the
effects of the systematic errors on the best values of and
and to propagate the statistical errors of the model parameters
fixed by other measurements. We also implement various statistical tests to
investigate the consistency of the available RCS data sets below
pion-production threshold and we conclude that there are not strong motivations
to exclude any data point from the global set. Our analysis yields and , with p-value .Comment: 19 pages, 11 figures, 4 tables; final version accepted for
publication in J. Phys.
First extraction of the scalar proton dynamical polarizabilities from real Compton scattering data
We present the first attempt to extract the scalar dipole dynamical
polarizabilities from proton real Compton scattering data below pion-production
threshold. The theoretical framework combines dispersion relations technique,
low-energy expansion and multipole decomposition of the scattering amplitudes.
The results are obtained with statistical tools that have never been applied so
far to Compton scattering data and are crucial to overcome problems inherent to
the analysis of the available data set.Comment: 8 pages, 4 figures, 2 tables; extended version to appear in Phys.
Rev.
Bi-Hamiltonian Aspects of a Matrix Harry Dym Hierarchy
We study the Harry Dym hierarchy of nonlinear evolution equations from the
bi-Hamiltonian view point. This is done by using the concept of an S-hierarchy.
It allows us to define a matrix Harry Dym hierarchy of commuting Hamiltonian
flows in two fields that projects onto the scalar Harry Dym hierarchy. We also
show that the conserved densities of the matrix Harry Dym equation can be found
by means of a Riccati-type equation.Comment: Revised version, 22 pages; a section on reciprocal transformations
added. To appear in J. Math. Phys
Microservice Performance in Container- and Function-as-a-Service Architectures
Function-as-a-Service (FaaS) is a new cloud-based computing model that promises a more cost-efficient deployment of microservices with respect to other cloud paradigms, like Container-as-a-Service (CaaS). However, requests served under a FaaS approach often experience a cold start condition, that occurs when the execution of an inactive function occurs for the first time and a container environment has to be set up afresh. In such cases, performance deteriorates and response times increase. This paper proposes an analysis of the performance of the Function-as-a-Service model for two single offered microservices. Specifically, we carry out a performance evaluation of the Function-as-a-Service model, implemented through OpenWhisk, using as a baseline for comparison the Container-as-a-Service approach, implemented with Docker. Our analysis focuses on metrics related to the response time and to the usage of main server resources such as CPU and memory. For the performance comparison, we exploited two different microservices based on face recognition and image conversion, respectively, in order to evaluate the performance over popular and modern kinds of services included in artificial intelligence and multimedia applications
A 3-component extension of the Camassa-Holm hierarchy
We introduce a bi-Hamiltonian hierarchy on the loop-algebra of sl(2) endowed
with a suitable Poisson pair. It gives rise to the usual CH hierarchy by means
of a bi-Hamiltonian reduction, and its first nontrivial flow provides a
3-component extension of the CH equation.Comment: 15 pages; minor changes; to appear in Letters in Mathematical Physic
Evaluation of the gn-->pi-p differential cross sections in the Delta-isobar region
Differential cross sections for the process gn-->pi-p have been extracted
from MAMI-B measurements of gd-->pi-pp, accounting for final-state interaction
effects, using a diagrammatic technique taking into account the NN and piN
final-state interaction amplitudes. Results are compared to previous
measurements of the inverse process, pi-p--> ng, and recent multipole analyses.Comment: 6 pages, 4 figures. v2: Further clarifications and minor changes. A
new figure inserte
Involutive orbits of non-Noether symmetry groups
We consider set of functions on Poisson manifold related by continues
one-parameter group of transformations. Class of vector fields that produce
involutive families of functions is investigated and relationship between these
vector fields and non-Noether symmetries of Hamiltonian dynamical systems is
outlined. Theory is illustrated with sample models: modified Boussinesq system
and Broer-Kaup system.Comment: LaTeX 2e, 10 pages, no figure
The Sato Grassmannian and the CH hierarchy
We discuss how the Camassa-Holm hierarchy can be framed within the geometry
of the Sato Grassmannian.Comment: 10 pages, no figure
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