Superluminal neutrino and spontaneous breaking of Lorentz invariance
F. R. Klinkhamer, G. E. Volovik^*°.
+Institute for Theoretical Physics, University of Karlsruhe, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany
*Low Temperature Laboratory, Aalto University, FI-00076 AALTO, Finland
°Landau Institute for Theoretical Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia
Generally speaking, the existence of
a superluminal neutrino can be attributed either
to re-entrant Lorentz violation at ultralow energy
from intrinsic Lorentz violation at ultrahigh energy
or to spontaneous breaking of fundamental Lorentz invariance
(possibly by the formation of a fermionic condensate).
Re-entrant Lorentz violation in the neutrino sector has been
discussed elsewhere. Here, the focus is on mechanisms
of spontaneous symmetry breaking.