[Landau ITP Seminars] Colloquium 07.05.2020

[Serge Krashakov]

Уважаемые сотрудники ИТФ,

В четверг 7 мая 2018 (не в пятницу!!!) в 11:30 состоится онлайн 
коллоквиум, на котором будет заслушан доклад:

Paolo Maria Santini (Dept. of Physics, University of Roma "La Sapienza")
*Towards an analytic description of periodic anomalous waves in nature 
via the focusing NLS model *(joint work with P. G. Grinevich)

The focusing NLS equation is the simplest universal model describing the 
modulation instability (MI) of quasi monochromatic waves in weakly 
nonlinear media, and MI is considered the main physical mechanism for 
the appearence of anomalous (rogue) waves (AWs) in nature. We first show 
how the finite gap method adapts to the NLS Cauchy problem for a generic 
periodic initial perturbation of the unstable background solution, in 
the case of a finite number N of unstable modes, allowing one to 
construct the solution, to leading order, in terms of elementary 
functions of the initial data. In particular, if N=1, one obtains the 
analytic quantitative description of a Fermi-Pasta-Ulam recurrence of 
AWs already observed in real (water wave and nonlinear optics) and 
numerical experiments. Then we present the analytic description of the 
O(1) effect of a small loss or gain on the dynamics of periodic AWs, in 
full agreements with recent water wave and numerical experiments. If 
time remains, we shall discuss analogies and differences with AWs in 
other contexts: on the Ablowitz-Ladik lattice and in the massive 
Thirring model relativistic field theory (with F. Coppini).

Адрес для подключения - http://bbb2.itp.ac.ru/b/a-o-ytc-2k3
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