In 2010 it became possible to directly compute, star by star, N-body simulations of a globular cluster over the course of its lifetime.
His speciality is the N-body simulation of galaxies and star clusters.
He is a computational astrophysicist who studies the growth of structure in the universe via gravitational N-body simulations.
On small scales, gravitational collapse is non-linear, and can only be computed accurately using N-body simulations.
It runs astrophysical N-body simulations with over 3,000,000,000 particles using the Multiple-Walk parallel treecode.
It is now often used as toy model in N-body simulations of stellar systems.
At this point non-linear structures begin to form, and the computational problem becomes much more difficult, involving, for example, N-body simulations with billions of particles.
He is famous for his theoretical studies of dark matter halos accompanied by massive N-body simulations.
Direct N-body simulations are used to study the dynamical evolution of star clusters.
For example, an N-body simulation of a star cluster might have a particle per star, so each particle has some physical significance.