On the dynamical behaviour of the generalized Ricci flow
Alberto Raffero, Luigi Vezzoni
TL;DR
This work studies the dynamical behavior of the generalized Ricci flow on compact manifolds with a fixed background closed 3-form $\hat{H}$ by employing the variational functional $\mu(g,b)=\lambda(g,\hat{H}+db)$. The authors establish a Lojasiewicz-Simon inequality for $\mu$ and implement a Nash–Moser gauge fixing to derive a DeTurck-type reformulation, enabling a gradient-flow analysis of the flow. The main results show dynamical stability: if $(\hat{g},0)$ is a local maximizer of $\mu$, solutions starting nearby exist globally and converge to a Ricci-flat metric modulo diffeomorphisms; conversely, non-maximizers yield dynamical instability in the form of nontrivial ancient solutions converging to $(\hat{g},0)$ as $t\to -\infty$. Overall, the paper extends stability results from Ricci flow to the generalized setting and connects the dynamics to a variational framework via $\mu$.
Abstract
Motivated by Müller-Haslhofer results on the dynamical stability and instability of Ricci-flat metrics under the Ricci flow, we obtain dynamical stability and instability results for pairs of Ricci-flat metrics and vanishing 3-forms under the generalized Ricci flow.
