Phase transition from Weyl to self-linked semimetal using bi-circular laser

The Fermi surface topology of a triple non-hermitian (NH) Weyl semimetal (WSM) driven by bi-circularly polarized light is presented in this study. A NH WSM in particular has remarkable outlines. Bi-circular light, however, modifies the symmetry features of non-hermitian triple Weyl and causes an unusual new kind of band swapping. We observe swapping between the imaginary bands (with or without exceptional degenaracies), which causes unique Fermi surfaces in the form of double rings and knots. This is something never discussed before phase transition between Weyl and knotted phases. We also discuss the corresponding changes in the Berry curvature as well.