Vortex to Rotons Transition in Dipolar Bose-Einstein Condensates

Recent experimental advancements enabled the creation of various systems exhibiting superfluid behavior, with one notable achievement being the development of dipolar Bose-Einstein condensates (dBECs). When confined along one or more spatial dimensions, these condensates exhibit a dispersion relation reminiscent of superfluid liquid helium, featuring a roton-like minimum. This study investigates the existence of two-dimensional solitary waves in dBECs characterised by topological defects (quantised vortices) and their transition to vortex-free Jones-Roberts solitons. The explicit connection between solitary waves and roton excitation is demonstrated, supporting Feynman's hypothesis regarding the nature of rotons as fading vortex excitations.