Multisoliton solutions and blow up for the $L^2$-critical Hartree equation

We construct multisoliton solutions for the $L^2$-critical Hartree equation with trajectories asymptotically obeying a many-body law for an inverse square potential.

Precisely, we consider the $m$-body hyperbolic and parabolic non-trapped dynamics.

The pseudo-conformal symmetry then implies finite-time collision blow up in the latter case and a solution blowing up at $m$ distinct points in the former case.

The approach we take is based on the ideas of [Krieger-Martel-Raphaël, 2009] and the third author's recent extension [Wu, 2026].

The approximation scheme requires new aspects in order to deal with a certain degeneracy for generalized root space elements.