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arXiv · 1102.2796

On the Kolmogorov-Sinai entropy of many-body Hamiltonian systems

Arul Lakshminarayan·Steven Tomsovic
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Abstract

The Kolmogorov-Sinai (K-S) entropy is a central measure of complexity and chaos. Its calculation for many-body systems is an interesting and important challenge. In this paper, the evaluation is formulated by considering $N$-dimensional symplectic maps and deriving a transfer matrix formalism for the stability problem. This approach makes explicit a duality relation that is exactly analogous to one found in a generalized Anderson tight-binding model, and leads to a formally exact expression for the finite-time K-S entropy. Within this formalism there is a hierarchy of approximations, the final one being a diagonal approximation that only makes use of instantaneous Hessians of the potential to find the K-S entropy. By way of a non-trivial illustration, the K-S entropy of $N$ identically coupled kicked rotors (standard maps) is investigated. The validity of the various approximations with kicking strength, particle number, and time are elucidated. An analytic formula for the K-S entropy within the diagonal approximation is derived and its range of validity is also explored.

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Arul Lakshminarayan, Steven Tomsovic. 2011-04-28. On the Kolmogorov-Sinai entropy of many-body Hamiltonian systems. https://doi.org/10.1103/physreve.84.016218

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