Dirac tachyons and antitachyons in many-particle system
  A consistent description of charged many-tachyon Fermi system is developed. Tachyons and antitachyons have the same chemical potential \mu+=\mu- because the axial coupling constant g+=g- is invariant under the charge conjugation, in contrast to reversion of the electric charge e+=-e-. The axial density n5=<\psi^ \gamma 5 \psi> is incorporated in the thermodynamical functions instead of <\psi^ \psi> which is not associated with any conserved quantity. The number of tachyons and antitachyons are undefined but it is possible to estimate their difference and establish a link between the total electric charge density $en$ and $n5$. 
Ernst Trojan
hep-ph