Antoniazzi Andrea, Califano Francesco, Fanelli Duccio, Ruffo Stefano
Dipartimento di Energetica and CSDC, Università di Firenze, and INFN, via S. Marta, 3, 50139 Firenze, Italy.
Phys Rev Lett. 2007 Apr 13;98(15):150602. doi: 10.1103/PhysRevLett.98.150602. Epub 2007 Apr 12.
We here discuss the emergence of quasistationary states (QSS), a universal feature of systems with long-range interactions. With reference to the Hamiltonian mean-field model, numerical simulations are performed based on both the original N-body setting and the continuum Vlasov model which is supposed to hold in the thermodynamic limit. A detailed comparison unambiguously demonstrates that the Vlasov-wave system provides the correct framework to address the study of QSS. Further, analytical calculations based on Lynden-Bell's theory of violent relaxation are shown to result in accurate predictions. Finally, in specific regions of parameters space, Vlasov numerical solutions are shown to be affected by small scale fluctuations, a finding that points to the need for novel schemes able to account for particle correlations.
我们在此讨论准稳态（QSS）的出现，这是具有长程相互作用的系统的一个普遍特征。参照哈密顿平均场模型，基于原始的N体设置和假定在热力学极限下成立的连续弗拉索夫模型进行了数值模拟。详细比较明确表明，弗拉索夫波系统为研究QSS提供了正确的框架。此外，基于林登 - 贝尔剧烈弛豫理论的解析计算结果显示出准确的预测。最后，在参数空间的特定区域，弗拉索夫数值解被证明受到小尺度波动的影响，这一发现表明需要能够考虑粒子相关性的新方案。
