s . po p - ph ] 1 9 N ov 1 99 7 Faster Than Light ?

In this paper we present a pedestrian review of the theoretical fact that all relativistic wave equations possess solutions of arbitrary velocities 0 ≤ v < ∞. We discuss some experimental evidences of v ≥ c transmission of electromagnetic field configurations and the importance of these facts with regard to the principle of relativity. Maxwell’s equations are a set of first order partial differential equations describing the behavior of the electric and magnetic fields generated by distributions of charges and currents. Such equations also possess solutions for the case where there are no charges nor currents. The simplest solutions of this kind, discovered by Maxwell himself, describe electromagnetic field configurations which we will call light-solutions (LS ). Light-solutions propagate in empty space with a particular velocity c (c ≈ 300, 000 km/s in MKS units). The simplest, easiest to find LS s are the plane wave solutions (PW ), which have the following important characteristics: (i) PW s are transverse waves: the electric ( ~ E) and magnetic ( ~ B) fields oscillate in time with a certain frequency and are perpendicular to the direction of propagation and to each other. (ii) The field invariants of PW s are null. In adequate units, where c = 1, these field invariants are given by I1 = ~ E. ~ B and I2 = ~ E 2 − ~ B2. [email protected] [email protected]