Chaotic motion of particles in the spacetime of a Kerr black hole immersed in swirling universes Deshui Cao, Lina Zhang, Songbai Chen, Qiyuan Pan and Jiliang Jing Eur. Phys. J. C, 85 1 (2025) 28 Published online: 18 January 2025 DOI: 10.1140/epjc/s10052-025-13749-2