Vortex solitons in Rydberg atoms system with twisted <i>PT</i> -symmetric photonic lattices

This study presents a theoretical model for generating vortex solitons (VSs) in a Rydberg atomic system with twisted <i>PT</i>-symmetric photonic lattices. Numerical simulations are conducted via the modified square operator and split-step Fourier methods. A diverse family of VSs, including ring-, four-core rhombus-, eight-core, four-core square-, and multi-core ring-shaped structures, are obtained by tuning system parameters, such as spatial lattice constant and radial index of input beam. Ring- and rhombus-shaped VSs exhibit universal existence and robust stability against perturbations. Linear spectral analysis uncovers a <i>PT</i>-symmetric to <i>PT</i>-broken phase transition in rhombus-shaped VSs, accompanied by eigenvalue degeneracy lifting under rotation. The stability of VSs is confirmed by propagation evolution. Additionally, the interplay of <i>PT</i>-symmetric gain-loss profiles and VS rotation induces power current exchange, generating secondary solitons. These insights advance the understanding of VS dynamics and offer potential for soliton-based photonic and quantum technologies.