Gravitational Hartree equation Created 2026-09-28 Updated 2026-11-05
The Gravitational Hartree equation couples a complex wave function to the attractive Newtonian gravitational potential generated by its own squared modulus. In dimension , a dimensionless convention iswhere and is the area of the unit sphere. The minus sign in the fundamental solution makes for nonnegative density, with the potential selected to decay at infinity when the convolution permits it.
The convolution makes the nonlinearity nonlocal: changing the density at one point changes the potential elsewhere. The Newtonian kernel and its dimension differ from a local cubic nonlinear Schrödinger equation. In three dimensions, the Hardy–Littlewood–Sobolev inequality controls the interaction energy and leads to Global H1 solutions of the three-dimensional gravitational Hartree equation.
Past exam of the mathematics course of the University of Cambridge 2021 iii Paper 154 2 3 Solution Created 2026-09-28 Updated 2026-10-03
In three dimensions, the Hardy–Littlewood–Sobolev inequality applied to the Newtonian kernel givesThe Gagliardo-Nirenberg interpolation inequality then givesWriting and using the conserved mass, conservation of energy impliesThus remains bounded. Together with the conserved norm this bounds , and the supplied blowup criterion proves Global H1 solutions of the three-dimensional gravitational Hartree equation.