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.
- Publication:
-
Modern Physics Letters A
- Pub Date:
- 2003
- DOI:
- arXiv:
- arXiv:hep-th/0307089
- Bibcode:
- 2003MPLA...18.2525T
- Keywords:
-
- 11.25.Db;
- 11.10.Kk;
- 11.55.Bq;
- Properties of perturbation theory;
- Field theories in dimensions other than four;
- Analytic properties of S matrix;
- High Energy Physics - Theory
- E-Print:
- 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