Understanding the FPU state in FPU-like models

Understanding the FPU state in FPU-like models

Blog Article

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-wavelength normal modes are excited.The FPU state has been observed, in particular, to obey a few characterizing scalings laws.The aim of this paper is twofold: click here First, reviewing and commenting the literature on the FPU state, suggesting a possible way to organize it.

Second, contributing to a better understanding of the FPU state by studying the similar state in the Toda model, which provides, as is known, the closest integrable approximation to FPU.As a new tool, we analyze the dimensionality of Toda invariant tori in states corresponding to the FPU state, and observe it obeys the main scaling law characterizing johnny cash style clothing the FPU state.