His QMC work was done while at the Lawrence Berkeley Laboratory (LBL) from 1980 to 1988, initially working there as a staff scientist in the National Resource for Computation in Chemistry (NRCC). His renormalization group work focused on geometric phase transitions such as percolation and their connection to disordered lattice spin models. That work was done as part of his PhD work at MIT and as an assistant research professor at Boston University (BU).