- 00-46 C. P. Dettmann, E. G. D. Cohen
- Microscopic chaos and diffusion
(411K, latex, uses revtex, epsfig)
Jan 27, 00
(auto. generated ps),
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Abstract. We investigate the connections between microscopic chaos,
defined on a dynamical level and arising from collisions between molecules,
and diffusion, characterized by a mean square displacement proportional
to the time. We use a number of models involving a single particle moving
in two dimensions and colliding with fixed scatterers. We find that a number
of microscopically nonchaotic models exhibit diffusion,
and that the standard methods of
chaotic time series analysis are ill suited to the problem of distinguishing
between chaotic and nonchaotic microscopic dynamics.
However, we show that periodic orbits
play an important role in our models, in that their different properties
in chaotic and nonchaotic systems can be used to distinguish such systems
at the level of time series analysis, and in systems with absorbing boundaries.
Our findings are relevant to experiments aimed at
verifying the existence of chaotic microscopic dynamics in diffusive systems.