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pro vyhledávání: '"A Ponno"'
The dynamics of initial long-wavelength excitations of the Fermi-Pasta-Ulam-Tsingou chain has been the subject of intense investigations since the pioneering work of Fermi and collaborators. We have recently found a new regime where the spectrum of t
Externí odkaz:
http://arxiv.org/abs/2407.16534
Publikováno v:
J. Stat. Phys. 190, 131 (2023)
We prove that the common Mie-Lennard-Jones (MLJ) molecular potentials, appropriately normalized via an affine transformation, converge, in the limit of hard-core repulsion, to the Toda exponential potential. Correspondingly, any Fermi-Pasta-Ulam (FPU
Externí odkaz:
http://arxiv.org/abs/2307.00596
Publikováno v:
Phys. Rev. Lett. 129, 114101 (2022)
We prove analytically and show numerically that the dynamics of the Fermi-Pasta-Ulam-Tsingou chain is characterised by a transient Burgers turbulence regime on a wide range of time and energy scales. This regime is present at long wavelengths and ene
Externí odkaz:
http://arxiv.org/abs/2208.08818
Autor:
Gallone, Matteo, Ponno, Antonio
Publikováno v:
Qualitative Properties of Dispersive PDEs. INdAM 2021. Springer INdAM Series, vol 52. Springer, Singapore (2022)
In the present work we analyse the structure of the Hamiltonian field theory in the neighbourhood of the wave equation $q_{tt}=q_{xx}$. We show that, restricting to ``graded'' polynomial perturbations in $q_x$, $p$ and their space derivatives of high
Externí odkaz:
http://arxiv.org/abs/2202.13454
In this paper we construct a higher order expansion of the manifold of quasi unidirectional waves in the Fermi-Pasta-Ulam (FPU) chain. We also approximate the dynamics on this manifold. As perturbation parameter we use $h^2=1/n^2$, where $n$ is the n
Externí odkaz:
http://arxiv.org/abs/2010.03520
Publikováno v:
Comm. Math. Phys. 380 (2020), no. 2, 811-851
We consider the Fermi-Pasta-Ulam-Tsingou (FPUT) chain composed by $N \gg 1$ particles and periodic boundary conditions, and endow the phase space with the Gibbs measure at small temperature $\beta^{-1}$. Given a fixed ${1\leq m \ll N}$, we prove that
Externí odkaz:
http://arxiv.org/abs/2001.08070
FPU models, in dimension one, are perturbations either of the linear model or of the Toda model; perturbations of the linear model include the usual $\beta$-model, perturbations of Toda include the usual $\alpha+\beta$ model. In this paper we explore
Externí odkaz:
http://arxiv.org/abs/1801.05199
Autor:
Carati, Andrea, Ponno, Antonio
We study, both numerically and analytically, the time needed to observe the breaking of an FPU $\alpha$-chain in two or more pieces, starting from an unbroken configuration at a given temperature. It is found that such a "chopping" time is given by a
Externí odkaz:
http://arxiv.org/abs/1705.00932
Autor:
Giancarlo Benettin, Antonio Ponno
Publikováno v:
Mathematics in Engineering, Vol 3, Iss 3, Pp 1-22 (2021)
Many papers investigated, in a variety of ways, the so-called "FPU state" in the Fermi-Pasta-Ulam model, namely the state, intermediate between the initial state and equipartition, that the system soon reaches if initially one or a few long-wavelengt
Externí odkaz:
https://doaj.org/article/3ca444f222be45069afc043007000ae5
Autor:
Dario Bambusi, Antonio Ponno
Publikováno v:
Journal of Mathematics in Industry, Vol 10, Iss 1, Pp 1-7 (2020)
Abstract We propose a mechanism explaining the approximately linear growth of Covid19 world total cases as well as the slow linear decrease of the daily new cases (and daily deaths) observed (in average) in USA and Italy. In our explanation, we regar
Externí odkaz:
https://doaj.org/article/72baa8029eca4e75b46d85ef5d585899