Eur. Phys. J. C 25, 479-486 (2002)
DOI: 10.1007/s10052-002-01018-7

Time-ordered perturbation theory on non-commutative spacetime II: Unitarity

Y. Liao and K. Sibold

Institut für Theoretische Physik, Universität Leipzig, Augustusplatz 10/11, 04109 Leipzig, Germany

(Received: 25 June 2002 / Published online: 30 August 2002 )

Abstract
We examine the unitarity issue in the recently proposed time-ordered perturbation theory on noncommutative (NC) spacetime. We show that unitarity is preserved as long as the interaction Lagrangian is explicitly hermitian. We explain why it makes sense to distinguish the hermiticity of the Lagrangian from that of the action in perturbative NC field theory and how this requirement fits in this framework.

© Società Italiana di Fisica, Springer-Verlag 2002