1967/07/25 by G. Feinberg · 17 citations
Physics and Astronomy · #Relativity and Gravitational Theory #Quantum Mechanics and Applications #Quantum and Classical Electrodynamics
paper · doi:10.1103/physrev.159.1089
openalex publication_date 1967/07/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/05
We consider the possibility of describing, within the special theory of relativity, particles with spacelike four-momentum, which therefore have velocities greater than that of light in vacuum. The usual objections to such particles are discussed, and they are found to be unconvincing within the framework of relativistic quantum theory. A quantum field theory of noninteracting, spinless, faster-than-light particles is described. The field theory is Lorentz-invariant, but must be quantized with Fermi statistics. The associated particle theory has the property that the particle number is not Lorentz-invariant, and the no-particle state is not Lorentz-invariant either. Nevertheless, the principle of relativity is satisfied. The Lorentz invariance implies a relation between emission and absorption processes, in contradiction to the usual case. Some comments are made about the problem of introducing interactions into the field theory. The limiting velocity is c, but a limit has two sides.