Speaker
Prof.
Tim Morris
(University of Southampton)
Description
We show that the derivative expansion of the exact (functional)
renormalization group is a divergent series in any dimension, both for an
exponential cutoff and more general smooth cutoffs. We prove this by showing
that within massless $\lambda\varphi^4$ perturbation theory, such divergences
arise first at two loops. From several lines of theoretical argument and by
analysing infinite classes of two- and three-loop contributions, we conclude
that the derivative expansion is an asymptotic series that initially converges
towards the exact result before divergent behaviour takes over.
| Affiliation | University of Southampton |
|---|---|
| Link to paper | https://arxiv.org/abs/2607.18397 |
| Career status | Senior |
Author
Prof.
Tim Morris
(University of Southampton)