Thermalization without chaos in harmonic systems

Recent numerical results showed that thermalization of Fourier modes is achieved in short time-scales in the Toda model, despite its integrability and the absence of chaos. Here we provide numerical evidence that the scenario according to which chaos is irrelevant for thermalization is realized even in the simplest of all classical integrable system: the harmonic chain. We study relaxation from an atypical condition given with respect to random modes, showing that a thermal state with equilibrium properties is attained in short times. Such a result is independent from the orthonormal basis used to represent the chain state, provided it is a random basis. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Recent numerical results indicate that the thermalization of Fourier modes can be achieved in a short time scale in the Toda model, despite its integrability and lack of chaos. This study provides numerical evidence that the irrelevant nature of chaos for thermalization is realized even in the simplest classical integrable system, such as the harmonic chain.