Transition from mode-locked periodic orbit to chaos in a 2D piecewise smooth non-invertible map

TL;DR

This paper investigates a novel route to chaos in a 2D piecewise smooth non-invertible map, highlighting the formation and destruction of invariant structures and the resulting basin topology changes.

Contribution

It introduces a new transition mechanism to chaos involving resonance tori and homoclinic bifurcations in non-invertible maps, differing from known scenarios.

Findings

Resonance torus forms from unstable manifolds and cycles.

Cusp torus does not develop before chaos onset.

Basin of attraction becomes nonconnected after bifurcation.

Abstract

In this work we report a new route to chaos from a resonance torus in a piecewise smooth non-invertible map of the plane into itself. The closed invariant curve defining the resonance torus is formed by the union of unstable manifolds of saddle cycle and the points of stable cycle and saddle cycle. We have found that a cusp torus cannot develop before the onset of chaos, though the loop torus appears. The destruction of the two-dimensional torus occurs through homoclinic bifurcation in the presence of an infinite number of loops on the invariant curve. We show that owing to the non-invertible nature of the map, the structure of the basin of attraction changes from simply connected to a nonconnected one. We also describe how the mechanism of transition to chaos differs from the scenario of appearance of chaos in invertible maps as well as in smooth non-invertible maps.