Nonlinear Sciences, Pattern Formation and Solitons, Pattern Formation and Solitons (nlin.PS), Chaotic Dynamics (nlin.CD)
journal:
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date:
2023-11-01 16:00:00
Abstract
A phenomenon of emergence of stability islands in phase-space is reported for two periodic potentials with tiling symmetries, one square and other hexagonal, as inspired by bidimensional Hamiltonian models of optical lattices. The structures found, here named as island myriads, resemble web-tori with notable fractality and arise at energy levels reaching that of unstable equilibrium points. In general, the myriad is an arrangement of concentric island chains with properties relying on the translational and rotational symmetries of the potential functions. In the square system, orbits within the myriad come in isochronous pairs and can have different periodic closure, either returning to their initial position or jumping to identical sites in neighbor cells of the lattice, therefore impacting transport properties. As seen when compared to the generic case, i.e. the rectangular lattice, the breaking of square symmetry disrupts the myriad even for small deviations from its equilateral configuration. For the hexagonal case, the myriad was found but in attenuated form, mostly due to extra instabilities in the potential surface that prevent the stabilization of orbits forming the chains.