CAUSALITY VIOLATION IN NONLOCAL QUANTUM FIELD THEORY

摘要: We study the causality violation in nonlocal ϕ4-theory (as formulated by Kleppe and Woodard) containing a finite mass scale Λ. Starting from Bogoliubov–Shirkov criterion for causality, we construct combinations of S-matrix elements that signal one-loop approximation. find exclusive process ϕ+ϕ→ϕ+ϕ grows with energy, but growth (for low to moderate energies) is suppressed all orders compared what one would expect purely dimensional considerations. however other processes such as ϕ+ϕ→ϕ+ϕ+ϕ+ϕ energy expected considerations at energies. For high enough energies comparable Λ, however, rapid (exponential-like) degree violation. suggest scenario, based on an earlier work, will enable evade large theoretical energies, should it be unobserved experimentally.