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Unitarity of noncommutative field theories from string theory

Alessandro Torrielli
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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.

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Alessandro Torrielli. 2003-07-09. Unitarity of noncommutative field theories from string theory. https://doi.org/10.1142/s0217732303012775

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