Complex dynamics in two-dimensional coupling of quadratic maps

Anca Rădulescu, Eva Kaslik, Alexandru Fikl

arXiv

Abstract

This paper examines the structure and limitations of equi-M sets in two-dimensional Complex Quadratic Networks (CQNs). In particular, we aim to describe the relationship between the equi-M set and the parameter domains where the critical orbit converges to periodic attractors (pseudo-bulbs). The two-node case serves as a foundational testbed: its analytical tractability enables the identification of critical phenomena and their dependence on coupling, while offering insight into more general principles. The two-node case is also simple enough to allow for explicit coupling conditions that govern phase transitions between synchronized and desynchronized behavior. Using a combination of analytical and numerical methods, the study reveals that while the period-1 pseudo-bulb closely tracks the boundary of the equi-M set near its main cusp, this correspondence breaks down for higher periods and in regions supporting coexisting attractors. These discrepancies highlight key differences between single-map and coupled dynamics, where equi-M sets no longer provide a full encoding of system combinatorics. These findings clarify the topological and dynamical behavior of low-dimensional CQNs and point toward a sharp increase in complexity as the number of nodes grows, laying the groundwork for future studies of high-dimensional dynamics.

BibTeX

@article{RadulescuKaslikFikl2025,
  title         = {Complex dynamics in two-dimensional coupling of quadratic maps},
  author        = {Anca R\u{a}dulescu and Eva Kaslik and Alexandru Fikl},
  year          = 2025,
  month         = may,
  day           = 19,
  doi           = {10.48550/arXiv.2303.09329},
  url           = {https://arxiv.org/abs/2303.09329},
  eprint        = {2303.09329},
  archiveprefix = {arXiv},
  primaryclass  = {nlin.CD},
  abstract      = {
    This paper examines the structure and limitations of equi-M sets in
    two-dimensional Complex Quadratic Networks (CQNs). In particular, we aim to
    describe the relationship between the equi-M set and the parameter domains
    where the critical orbit converges to periodic attractors (pseudo-bulbs).
    The two-node case serves as a foundational testbed: its analytical
    tractability enables the identification of critical phenomena and their
    dependence on coupling, while offering insight into more general
    principles. The two-node case is also simple enough to allow for explicit
    coupling conditions that govern phase transitions between synchronized and
    desynchronized behavior. Using a combination of analytical and numerical
    methods, the study reveals that while the period-1 pseudo-bulb closely
    tracks the boundary of the equi-M set near its main cusp, this
    correspondence breaks down for higher periods and in regions supporting
    coexisting attractors. These discrepancies highlight key differences
    between single-map and coupled dynamics, where equi-M sets no longer
    provide a full encoding of system combinatorics. These findings clarify the
    topological and dynamical behavior of low-dimensional CQNs and point toward
    a sharp increase in complexity as the number of nodes grows, laying the
    groundwork for future studies of high-dimensional dynamics.
  },
}