Existence of multisoliton solutions of the gravitational Hartree equation in three dimensions
Yutong Wu
TL;DR
The work establishes the existence of multisoliton solutions to the 3D gravitational Hartree equation $iu_t+\Delta u-\phi_{|u|^2}u=0$ whose centers track expansive $m$-body dynamics across hyperbolic, parabolic, or hyperbolic–parabolic regimes. By constructing high-order approximate multisolitons and developing a robust modulation framework, the authors reduce the problem to controlling a small error in $H^1$ via a bootstrap, coercivity of linearized operators $L_+$ and $L_-$, and a Lyapunov-type functional $\mathcal G(\varepsilon)$. A key innovation is a detailed dipole-like expansion of the nonlocal Hartree interaction, enabling cancellation of long-range effects up to order $N$ and allowing the error to decay despite the nonlocal tail $\phi_{|u|^2}(x)\sim 1/|x|$. The result generalizes the two-soliton construction of Krieger–Martel–Raphaël to arbitrary $m$, providing a concrete realization of multisolitons consistent with the $m$-body dynamics and advancing the soliton-resolution program for nonlocal dispersive systems.
Abstract
We prove the existence of multisoliton solutions of the three-dimensional gravitational Hartree equation whose trajectories follow many body dynamics of hyperbolic, parabolic or hyperbolic-parabolic types. This work generalizes and improves the result of Krieger-Martel-Raphaël on two-soliton solutions.
