Report on 2203.08108v2

Abstract

We generalize the vertex expansion approach of the functional renormalization group to non-Hermitian systems.As certain anomalous expectation values might not vanish, additional terms as compared to the Hermitian case can appear in the flow equations.We investigate the merits and shortcomings of the vertex expansion for non-Hermitian systems by considering an exactly solvable PT -symmetric non-linear toy-model and reveal, that in this model, the fidelity of the vertex expansion in a perturbatively motivated truncation schema is comparable with that of the Hermitian case.The vertex expansion appears to be a viable method for studying correlation effects in non-Hermitian systems.

Authors 3

1. Lukas Grunwald corresponding Aachen Institut für Theorie der Statistischen Physik

   RWTH Aachen University

   Affiliation as printed

   Institut für Theorie der Statistischen Physik , RWTH Aachen University , 52056 Aachen , Germany

   Institut für Theorie der Statistischen Physik, RWTH Aachen University, 52056 Aachen, Germany

2. V. Meden Aachen Institut für Theorie der Statistischen Physik

   RWTH Aachen University

   Affiliation as printed

   Institut für Theorie der Statistischen Physik , RWTH Aachen University , 52056 Aachen , Germany

   Institut für Theorie der Statistischen Physik, RWTH Aachen University, 52056 Aachen, Germany

3. Dante Marvin Kennes Aachen Institut für Theorie der Statistischen Physik

   RWTH Aachen University · Max Planck Institute for the Structure and Dynamics of Matter

   Affiliation as printed

   Institut für Theorie der Statistischen Physik , RWTH Aachen University , 52056 Aachen , Germany

   Max Planck Institute for the Structure and Dynamics of Matter , 22761 Hamburg , Germany

   Institut für Theorie der Statistischen Physik, RWTH Aachen University, 52056 Aachen, Germany

   Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany