He received his PhD in 1980 at the Niels Bohr Institute in Copenhagen, followed by postdoctoral research positions at Caltech and Nordita.
It provides a very simple physical realisation of anti-screening, an effect associated with asymptotically free quantum field theories.
Together with B. Durhuus and Jürg Fröhlich he proposed a non-perturbative formulation of the boson string theory, using what became known as dynamical triangulation.
The formalism provides a successful description of so-called non-critical strings, which can also be viewed as two-dimensional quantum gravity coupled to matter with a central charge c<1.
The model was first proposed in two-dimensional spacetime, where it could be solved analytically, and later generalized to three and four dimensions by Ambjørn, Loll and J. Jurkiewicz.