1,178 research outputs found
Hadron-Hadron Interactions from Lattice QCD: isospin-1 scattering length
We present results for the interaction of two kaons at maximal isospin. The
calculation is based on flavour gauge configurations generated by
the European Twisted Mass Collaboration with pion masses ranging from about
to at three values of the lattice spacing. The
elastic scattering length is calculated at several values of the
bare strange and light quark masses. We find as
the result of a combined extrapolation to the continuum and to the physical
point, where the first error is statistical, and the three following are
systematical. This translates to .Comment: 28 pages, 18 tables, 14 figure
Coupled Dynamics on Hypergraphs: Master Stability of Steady States and Synchronization
In the study of dynamical systems on networks/graphs, a key theme is how the
network topology influences stability for steady states or synchronized states.
Ideally, one would like to derive conditions for stability or instability that
instead of microscopic details of the individual nodes/vertices rather make the
influence of the network coupling topology visible. The master stability
function is an important such tool to achieve this goal. Here we generalize the
master stability approach to hypergraphs. A hypergraph coupling structure is
important as it allows us to take into account arbitrary higher-order
interactions between nodes. As for instance in the theory of coupled map
lattices, we study Laplace type interaction structures in detail. Since the
spectral theory of Laplacians on hypergraphs is richer than on graphs, we see
the possibility of new dynamical phenomena. More generally, our arguments
provide a blueprint for how to generalize dynamical structures and results from
graphs to hypergraphs
Meson-meson scattering lengths at maximum isospin from lattice QCD
We summarize our lattice QCD determinations of the pion-pion, pion-kaon and
kaon-kaon s-wave scattering lengths at maximal isospin with a particular focus
on the extrapolation to the physical point and the usage of next-to-leading
order chiral perturbation theory to do so. We employ data at three values of
the lattice spacing and pion masses ranging from around 230 MeV to around 450
MeV, applying Luescher's finite volume method to compute the scattering
lengths. We find that leading order chiral perturbation theory is surprisingly
close to our data even in the kaon-kaon case for our entire range of pion
masses.Comment: 10 pages, 8 figures, Presented at the 9th International Workshop on
Chiral Dynamics, Sept. 17-21, 2018, Duke University, Durham, NC, USA ,
submitted to PoS, (C18-09-17.6). Funding acknowledgements added in v2
replacement, comma added in abstract. In v3 replacement, corrected typo in
equation 6.2 which was referring to the pion-kaon reduced mass instead of the
pion mas
Hadron-Hadron Interactions from Lattice QCD: Scattering Length
In this paper we report on results for the s-wave scattering length of the
- system in the channel from Lattice QCD. The
calculation is based on gauge configurations generated by the European Twisted
Mass Collaboration with pion masses ranging from about to
at three values of the lattice spacing. Our main result reads
. Using chiral perturbation theory
we are also able to estimate . The
error includes statistical and systematic uncertainties, and for the latter in
particular errors from the chiral and continuum extrapolations.Comment: 30 pages, 6 figures, 15 table
Bibliographie de l’île de Clipperton – Île de La Passion (1711-2005)
L’île de Clipperton, baptisée « Île de La Passion » par ses découvreurs français en 1711, porte pourtant le nom d’un pirate anglais. Malgré les très courtes périodes d’occupation qu’elle connut au début du XXe siècle et dans les années 1960, son histoire est jalonnée de nombreux écrits. Son intérêt scientifique sur le plan des études environnmentales et les enjeux économique et géopolitique récemment renouvelés conduisent l’auteur à publier ici cette bibliographie de plus de trois cent cinquante références d’ouvrages, articles scientifiques, rapports, textes officiels, articles de presse, films et de quelques sites internet portant uniquement sur l’île.Yet Clipperton Island has been discovered and baptised Île de La Passion» by its French discoverors in 1711, its name is the one of a british pirate. Despite its short periods of occupation at the beginning of the 20th century and during the sixties, its history is ponctuated with numerous written works. Its high interest for environmental studies, and its recent renewed economic and geopoltical issues bring here the author to publish more than three hundred fifty references of books, articles, reports, administrative text, press papers, films et some websites only about the island
Gestion du risque et sécurité civile : résilience, adaptation, stratégies. Du diagnostic spatialisé au transfert de stratégie.
La prévention, la gestion, voire la réduction des impacts des catastrophes mobilisent toutes les sphères des sociétés. Elles suscitent un intérêt croissant et une demande de visibilité accrue dans de nombreux domaines de la connaissance, ce qui suppose le développement d’une expertise interdisciplinaire sans précédent. Toutefois, en dehors des milieux universitaires, aucune avancée notable n’est à remarquer et ce tout particulièrement en termes de stratégies à l’échelle et à destination des p..
The meson at the physical point with Wilson twisted mass fermions
We present results for the eta prime meson and the topological susceptibility
in two flavour lattice QCD. The results are obtained using Wilson twisted mass
fermions at maximal twist with pion masses ranging from 340 MeV down to the
physical point. A comparison to literature values is performed giving a handle
on discretisation effects.Comment: Lattice 2017 proceeding contributio
Representation of Markov chains by random maps: existence and regularity conditions
We systematically investigate the problem of representing Markov chains by
families of random maps, and which regularity of these maps can be achieved
depending on the properties of the probability measures. Our key idea is to use
techniques from optimal transport to select optimal such maps. Optimal
transport theory also tells us how convexity properties of the supports of the
measures translate into regularity properties of the maps via Legendre
transforms. Thus, from this scheme, we cannot only deduce the representation by
measurable random maps, but we can also obtain conditions for the
representation by continuous random maps. Finally, we present conditions for
the representation of Markov chain by random diffeomorphisms.Comment: 22 pages, several changes from the previous version including
extended discussion of many detail
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