1–5 Sept 2026
University of Sussex
Europe/London timezone

The $\theta$-vacuum from functional renormalisation

1 Sept 2026, 13:40
20m
144 (Jubilee Building)

144

Jubilee Building

Speaker

Yuepeng Guan (Jilin University)

Description

We study topological properties of a quantum mechanical system with $U(1)$-symmetry within the functional renormalisation group (fRG) approach. These properties include the vacuum energy structure and the topological susceptibility. Our approach works with a complexification of the flow equation, and specifically we embed the original symmetry into the complex plane, $U(1)\rightarrow \mathbb{C}$. We compute the effective potential of a given topological sector by restricting ourselves to field configurations with given generalised non-trivial Chern–Simons numbers. The full potential is directly constructed from these sector potentials. Our results compare well with the benchmark results obtained from solving the corresponding Schr\"odinger equation.

Affiliation Center for Theoretical Physics and College of Physics, Jilin University
Link to paper 2507.22318 [hep-th] or https://doi.org/10.1103/pryh-22dx
Career status PhD student

Authors

Jan M. Pawlowski Mr Masatoshi Yamada (Kwansei Gakuin University) Yuepeng Guan (Jilin University)

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