Berlin 2005 – wissenschaftliches Programm

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MP: Theoretische und Mathematische Grundlagen der Physik

MP 4: Quantum Field Theory and String Theory

MP 4.2: Fachvortrag

Dienstag, 8. März 2005, 14:20–14:40, TU MA043

Quantized equations of motion and currents in noncommutative theories — •Tobias Reichenbach — Konradstr. 58a, 04315 Leipzig

In this talk, quantized equations of motion and currents, that means equations on the level of Green’s functions, are studied within different perturbative approaches to noncommutative quantum field theories.

Time-space noncommutativity poses remarkable difficulties. The perturbative approach via modified Feynman rules has been shown to violate unitarity. Therefore, another approach has been suggested which is manifestly unitary(TOPT). We study equations of motion and currents on the level of Green’s functions within this framework, and find that the classical equations are not longer valid. This causes e.g. the violation of Ward identities in NCQED.

To cure this problem, a modified time-ordering has been proposed, which we present. We derive equations of motion in the new framework.

Another approach uses retarded functions. We introduce it and analyze unitarity as well as equatons of motion and currents. Both are disturbed for the same reason.We propose a modified theory which is unitary and preserves the classical equations of motion and currents on the quantized level.