Initial data for Minkowski stability with arbitrary decay
Allen Juntao Fang, Jérémie Szeftel, Arthur Touati
TL;DR
This work develops a framework to construct initial data for the Einstein vacuum equations that approximate Minkowski spacetime while prescribing arbitrary polynomial decay at infinity, with a focus on decays $r^{-q-oldsymbol{ abla}}$ for $q eq0$ and $0<oldsymbol{ abla}<1$. The authors employ a simplified conformal method, reduce to TT perturbations, and implement a nonlinear fixed-point strategy, augmented by a truncated Kerr black hole to absorb linear obstructions arising from cokernels of the constraint operator and the Laplacian. The main result (version 2) produces data of the form $g=u^4(e+ extpr{p-session})$ with $ extfrak{p}$ encoding Kerr parameters $(m,y,a,v)$ and TT perturbations $(reve{g},reve{ au})$, together with small corrections $( extfrak{u}, extfrak{X})$ and, in higher $q$, additional compactly supported corrections. The construction yields explicit control on the Kerr parameters: a positive mass bound $m eq0$, and bounds on the center of mass and angular momentum $|y|+|a|$ in terms of seed data, with a cone condition ensuring coercivity, and a fixed-point framework providing existence, uniqueness (for $q\ge3$), and quantitative a priori estimates. Overall, the paper furnishes a flexible, data-driven pathway to generate near-Minkowski initial data compatible with nonlinear stability results for Minkowski spacetime, including mass terms in the asymptotics, and it clarifies the role of obstruction spaces and truncations in elliptic constructions on $R^3$ with weighted decay.
Abstract
We construct and parametrize solutions to the constraint equations of general relativity in a neighborhood of Minkowski spacetime with arbitrary prescribed decay properties at infinity. We thus provide a large class of initial data for the results on stability of Minkowski which include a mass term in the asymptotics. Due to the symmetries of Minkowski, a naive linear perturbation fails. Our construction is based on a simplified conformal method, a reduction to transverse traceless perturbations and a nonlinear fixed point argument where we face linear obstructions coming from the cokernels of both the linearized constraint operator and the Laplace operator. To tackle these obstructions, we introduce a well-chosen truncated black hole around which to perturb. The control of the parameters of the truncated black hole is the most technical part of the proof, since its center of mass and angular momentum could be arbitrarily large.
