Volume preserving spacetime mean curvature flow and foliations of initial data sets
Jacopo Tenan
TL;DR
The work extends Huisken–Yau style volume-preserving curvature flow to a spacetime setting by introducing a generalized speed $\mathcal{H}=\sqrt[q]{H^q-|P|^q}$ on $C_{\frac12+\delta}^2$-asymptotically flat initial data with positive ADM energy. By combining a spectral analysis of the stability operator with a carefully chosen roundness class, the authors prove global existence and exponential convergence of the flow to a surface with constant spacetime curvature, thereby producing a CSTMC foliation that serves as a robust center-of-mass construction in General Relativity. The results recover the Cederbaum–Sakovich CSTMC foliation when $q=2$ and provide a broader framework for understanding how extrinsic curvature flows behave in asymptotically flat spacetimes, with implications for defining conserved quantities in isolated systems. Overall, the paper broadens the analytic toolkit for geometric flows in GR and strengthens the link between foliations by spacetime curvature and notions of center of mass in gravitating systems.
Abstract
We consider a volume preserving curvature evolution of surfaces in an asymptotically Euclidean initial data set with positive ADM-energy. The speed is given by a nonlinear function of the mean curvature which generalizes the spacetime mean curvature recently considered by Cederbaum-Sakovich (Calc. Var. PDE, 2021). Following a classical approach by Huisken-Yau (Invent. Math., 1996), we show that the flow starting from suitably round initial surfaces exists for all times and converges to a constant (spacetime) curvature limit. This provides an alternative construction of the CSTMC foliation by Cederbaum-Sakovich and has applications in the definition of center of mass of an isolated system in General Relativity.
