“Chaos” describes dynamical systems that exhibit sensitivity to initial conditions. This can be made mathematically precise, but it boils down to when you start with two initial conditions that are “close,” they will after some “sufficient” time be “far apart.”
For example, turbulent air flow is an example of a chaotic system. This is fundamentally the reason why weather forecasts become less accurate further in the future. The data that goes into the weather model does not have infinite precision, small errors eventually lead to large deviations in the state of the system.
I edited/clarified my comment before I saw your reply—apparently the restriction to three dimensions only apples to continuous-time systems, which is what I had in mind when I posted the question.
The physical motion of the billiards is two-dimensional, but wouldn’t the phase space be four-dimensional (since it tracks both position and momentum)?
I think the reason chaos needs at least three-dimensional phase space for continuous-time systems is that the orbits in phase space can’t intersect (which the paths of the billiards in real space obviously do).
“Chaos” describes dynamical systems that exhibit sensitivity to initial conditions. This can be made mathematically precise, but it boils down to when you start with two initial conditions that are “close,” they will after some “sufficient” time be “far apart.”
For example, turbulent air flow is an example of a chaotic system. This is fundamentally the reason why weather forecasts become less accurate further in the future. The data that goes into the weather model does not have infinite precision, small errors eventually lead to large deviations in the state of the system.
I edited/clarified my comment before I saw your reply—apparently the restriction to three dimensions only apples to continuous-time systems, which is what I had in mind when I posted the question.
I’m not sure what the author had in mind exactly, but it’s not accurate that at least 3D is required in continuous-time systems.
A common example in 2D is the chaotic billiard.
I am not familiar with the book and haven’t studied strange attractors.
The physical motion of the billiards is two-dimensional, but wouldn’t the phase space be four-dimensional (since it tracks both position and momentum)?
I think the reason chaos needs at least three-dimensional phase space for continuous-time systems is that the orbits in phase space can’t intersect (which the paths of the billiards in real space obviously do).