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Gauge dependence and Dyson Schwinger equations II

Subject Area Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
Mathematics
Term from 2017 to 2022
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 379766926
 

Final Report Abstract

The structure of gauge theory and the intricacies of their dependence on renormalization schemes and covariant gauges were the topic of this work. This included abelian and non-abelian gauge theories as well as quantum gravity viewed as a covariant gauge theory. The wider context were renormalizable quantum field theories in two, four, and higher (even) dimensions of spacetime. Our work led to insights into the structure of such theories in particular with regards to: • The self-consistency of off-shell Slavnon–Taylor identities. Using Hopf-algebraic structures as well as diagrammatic techniques for determining the Slavnov-Taylor identities for QCD we constructed the relations for the off-shell triple and quartic gluon vertices. Analytic checks confirmed the result in loop computations. • Algebraic Interplay between Renormalization and Monodromy. The Hopf algebra structure of renormalization theory and the analytic structure of the scattering S-matrix cover two very different aspects of quantum field theory. It was shown for the first time that they are intimately related though the structure of cointeracting bialgebras. • Gracey’s work as Mercator Fellow on various aspects of the structure of quantum field theories. One of the major activities was the work in relation to ultraviolet completeness and emergent symmetries through the compilation of new explicit high order perturbative and large N results. For instance, the five loop renormalization of the Wess-Zumino model in the MS and momentum subtraction (MOM) schemes advanced the forty year old 4 loop work to a new order. This level of precision meant Bellon and Schaposnik’s Hopf algebra (itself based on Kreimer’s work) could be analysed. • Off-shell Diagrammatics for Quantum Gravity. It was shown how diagrammatic identities of Yang–Mills theory translate to diagrammatics for pure gravity. By analogy to Yang–Mills theory, cancelation identities were confirmed up to six external gravitions.

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