Theoretical physicist; Educator
Mathematical and Physical Sciences
Theoretical physicist whose contributions range from high energy physics and quantum field theory to many areas of condensed matter physics such as the fractional quantum effect. He determined the exact quenched specific heat and correlation functions of a random-bond Ising model using the replica trick, the renormalization group and bosonization. He deduced the exact low-energy properties of fermions at finite density by eliminating modes near the Fermi surface. The truly marginal fixed point couplings correspond to Landau parameters and the BCS couplings are marginally relevant (irrelevant) when attractive (repulsive) at one loop. He provided an algebraic operator description of composite fermions to describe the fractional quantum Hall effect in the continuum (and recently in topological insulators). His quantum mechanics text, Principles of Quantum Mechanics(1994), is widely used throughout the world. He has also writtten Basic Training in Mathematics and Fundamentals of Physics.His engaging scientific lectures for the general public are well known for their substance, simplicity, and humor. His many awards include the Julius Edgar Lilienfeld Prize of the American Physical Society (2009).