The quasi-equilibrium phase of nonlinear chains

Pramana

Surajit Sen¹  T R Krishna Mohan1² 

[1] [e-mail]$$;CSIR Centre for Mathematical Modelling and Computer Simulation (C-MMACS), Bangalore 560 037, India$$

关键词: Solitary waves;    FPU chain;    equipartition;    quasi-equilibrium.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

We show that time evolution initiated via kinetic energy perturbations in conservative, discrete, spring-mass chains with purely nonlinear, non-integrable, algebraic potentials of the form 𝑉 (𝑥𝑖 − 𝑥𝑖+1 ∼ $(𝑥_{𝑖} − 𝑥_{𝑖+1})^{2𝑛}$, 𝑛 ≥ 2 and an integer, occurs via discrete solitary waves (DSWs) and discrete antisolitary waves (DASWs). Presence of reflecting and periodic boundaries in the system leads to collisions between the DSWs and DASWs. Such collisions lead to the breakage and subsequent reformation of (different) DSWs and DASWs. Our calculations show that the system eventually reaches a stable `quasi-equilibrium' phase that appears to be independent of initial conditions, possesses Gaussian velocity distribution, and has a higher mean kinetic energy and larger range of kinetic energy fluctuations as compared to the pure harmonic system with 𝑛 = 1; the latter indicates possible violation of equipartition.

【 授权许可】

Unknown