Tachyonic fields bifurcation at the light speed
Luxons, in the special relativity, are the massless particles with the invariant light speed [1] and thus are bifurcation points for the tachyonic field. Beyond light speed, exist superluminal tachyon bifurcation vibrators. Exciton-polariton X-waves are the superluminal wave equivalent [2]
[1] Chashchina, Silagadze, BREAKING THE LIGHT SPEED BARRIER, ACTA PHYSICA POLONICA B, 2012
[2] Antonio Gianfrate, et al., Superluminal X-waves in a polariton quantum fluid, nature, 2017