# Causality and unitarity via the tree-loop duality relation

@article{Tomboulis2017CausalityAU, title={Causality and unitarity via the tree-loop duality relation}, author={E. T. Tomboulis}, journal={Journal of High Energy Physics}, year={2017}, volume={2017}, pages={1-23} }

A bstractThe tree-loop duality relation is used as a starting point to derive the constraints of causality and unitarity. Specifically, the Bogoliubov causality condition is ab initio derived at the individual graph level. It leads to a representation of a graph in terms of lower order cut graphs. Extracting the absorptive part gives then the general unitarity relation (Cutkosky rule). The derivation, being carried out directly in momentum space, holds for any local (polynomial) hermitian…

## 40 Citations

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