https://arxiv.org/abs/1811.06949 pg 3 mentions that chaos is a common property of thermal systems. Can someone please explain why that is?
While looking at [1], I found that indeed most examples were that of thermal systems, however, I did not find any mention of why chaos is common in these systems.
[1] M. Cencini, F. Cecconi and A. Vulpiani, “Chaos: From Simple Models to Complex Systems,” World Scientific: Singapore, 2009
Chaos is common property of systems in general, not only thermal ones - in order to avoid chaos, you need to pick a system by hand, with a simple enough Hamiltonian, which you can't for the typical "thermal system".
In thermodynamics, though, the connection is deeper: thermal systems (in equilibrium) "can be thought of as 'moving through phase space' ergodically" [1], by which one often means chaotically: chaos can be considered a form of "strong ergodicity" (for details see this answer describing the ergodic hierarchy and, for even more resources on Statistical Mechanics & Dynamical Systems, you can check this question).
