Exact relations between homoclinic and periodic orbit actions in chaotic systems

TL;DR

This paper derives exact geometric relations linking homoclinic and periodic orbit actions in chaotic systems, enabling precise approximations and deeper understanding of orbit interrelations in semiclassical analyses.

Contribution

It introduces exact formulae connecting homoclinic and periodic orbit actions, facilitating accurate approximations and analysis of orbit relations in chaotic dynamics.

Findings

Derived exact relations between homoclinic and periodic orbit actions.

Provided explicit formulas for action differences in cycle expansions.

Enabled improved approximations of periodic orbit actions.

Abstract

Homoclinic and unstable periodic orbits in chaotic systems play central roles in various semiclassical sum rules. The interferences between terms are governed by the action functions and Maslov indices. In this article, we identify geometric relations between homoclinic and unstable periodic orbits, and derive exact formulae expressing the periodic orbit classical actions in terms of corresponding homoclinic orbit actions plus certain phase space areas. The exact relations provide a basis for approximations of the periodic orbit actions as action differences between homoclinic orbits with well-estimated errors. This make possible the explicit study of relations between periodic orbits, which results in an analytic expression for the action differences between long periodic orbits and their shadowing decomposed orbits in the cycle expansion.