Boost action on external field problems

Gebhard Grübl and Raimund Vogl

Institut für Theoretische Physik der Universität Innsbruck, A-6020 Innsbruck, Austria

Received 2 September 1991

Abstract. We study the behaviour of chiral fermions in two-dimensional space-time with an external potential under the action of Lorentz boosts. Quantization of the system such that the incoming field is in the physical vacuum representation of the fermionic field algebra associated with the canonical anticommutation relations (CAR) algebra, makes time evolution and boosts unitarily implemented at all times. The models are shown to possess an instantaneous particle interpretation in exceptional cases only. In the cases they do, in general this property is destroyed by boosts. Thus boost invariance of instantaneous vacua, as it has been conjectured recently, can be ruled out.

J. Phys. A: Math. Gen. 25, 2737 - 2744 (1992).