Unitarity of noncommutative field theories from string theory

Abstract

We improve the study of the lack of perturbative unitarity of noncommutative space-time quantum field theories derived from open string theory in electric backgrounds, enforcing the universality of the mechanism by which a tachyonic branch cut appears when the Seiberg-Witten limit freezes the string in an unstable vacuum. The main example is realized in the context of the on-shell four-tachyon amplitude of the bosonic string, and the dependence of the phenomenon on the brane-worldvolume dimension is analysed. We discuss the possibility of a proof in superstring theory, and finally mention the NCOS limit in this framework.

8 pages, no figures. Work done in collaboration with A. Bassetto and R. Valandro (Padua Univ.). Submitted for the proceedings of the conference "Spacetime and Fundamental Interactions: Quantum Aspects. A conference to honour A.P.Balachandran's 65th birthday", Vietri, 26-31 May 2003

References in corpus (1)

• The quantum structure of spacetime at the Planck scale and quantum fields

Cited by in corpus (4)

• Consistent Anomalies in Translation-Invariant Noncommutative Gauge Theories
• Scattering in Noncommutative Quantum Mechanics
• Noncommutative Decrumpling Inflation and Running of the Spectral Index
• One-loop unitarity of string theories in a constant external background and their Seiberg-Witten limit