Livorati André L P, Dettmann Carl P, Caldas Iberê L, Leonel Edson D
Departamento de Física, UNESP - Univ. Estadual Paulista, Ave. 24A, 1515, Bela Vista, 13506-900 Rio Claro, SP, Brazil.
School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom.
Chaos. 2015 Oct;25(10):103107. doi: 10.1063/1.4930843.
The transport and diffusion properties for the velocity of a Fermi-Ulam model were characterized using the decay rate of the survival probability. The system consists of an ensemble of non-interacting particles confined to move along and experience elastic collisions with two infinitely heavy walls. One is fixed, working as a returning mechanism of the colliding particles, while the other one moves periodically in time. The diffusion equation is solved, and the diffusion coefficient is numerically estimated by means of the averaged square velocity. Our results show remarkably good agreement of the theory and simulation for the chaotic sea below the first elliptic island in the phase space. From the decay rates of the survival probability, we obtained transport properties that can be extended to other nonlinear mappings, as well to billiard problems.
利用生存概率的衰减率对费米 - 乌拉姆模型速度的输运和扩散性质进行了表征。该系统由一组非相互作用粒子组成,这些粒子被限制在两个无限重的壁之间运动并经历弹性碰撞。其中一个壁是固定的,作为碰撞粒子的返回机制,而另一个壁则随时间做周期性运动。求解了扩散方程,并通过平均平方速度对扩散系数进行了数值估计。我们的结果表明,相空间中第一个椭圆岛下方混沌海的理论与模拟结果具有非常好的一致性。从生存概率的衰减率中,我们获得了可以扩展到其他非线性映射以及台球问题的输运性质。