Energy spreading,equipartition,and chaos in lattices with non-central forces  

作　　者：Yong-Jing Chen Yang Su Guoxiang Dong Li-Le Liu Zhigang GeXiaobao Wang 陈永静;宿阳;董国香;刘丽乐;葛智刚;王小保(China Nuclear Data Center,China Institute of Atomic Energy,Beijing 102413,China;School of Science,Huzhou University,Huzhou 313000,China)

机构地区：[1]China Nuclear Data Center,China Institute of Atomic Energy,Beijing 102413,China [2]School of Science,Huzhou University,Huzhou 313000,China

出　　处：《Chinese Physics B》2022年第2期119-128,共10页中国物理B（英文版）

基　　金：Supported by National Natural Science Foundation of China(11790325,11790320,11790321,11961131010,U1732138,11505056,11605054,U2067205,12105369,12047568,12147219);the Continuous Basic Scientific Research Project(WDJC-2019-09)。

摘　　要：We numerically study a one-dimensional,nonlinear lattice model which in the linear limit is relevant to the study of bending(flexural)waves.In contrast with the classic one-dimensional mass-spring system,the linear dispersion relation of the considered model has different characteristics in the low frequency limit.By introducing disorder in the masses of the lattice particles,we investigate how different nonlinearities in the potential(cubic,quadratic,and their combination)lead to energy delocalization,equipartition,and chaotic dynamics.We excite the lattice using single site initial momentum excitations corresponding to a strongly localized linear mode and increase the initial energy of excitation.Beyond a certain energy threshold,when the cubic nonlinearity is present,the system is found to reach energy equipartition and total delocalization.On the other hand,when only the quartic nonlinearity is activated,the system remains localized and away from equipartition at least for the energies and evolution times considered here.However,for large enough energies for all types of nonlinearities we observe chaos.This chaotic behavior is combined with energy delocalization when cubic nonlinearities are present,while the appearance of only quadratic nonlinearity leads to energy localization.Our results reveal a rich dynamical behavior and show differences with the relevant Fermi–Pasta–Ulam–Tsingou model.Our findings pave the way for the study of models relevant to bending(flexural)waves in the presence of nonlinearity and disorder,anticipating different energy transport behaviors.

关 键 词：Anderson localization energy spreading energy equipartition CHAOS 

分 类 号：O415[理学—理论物理]