A Quantum Monte Carlo method at fixed energy

In this paper we explore ways to study the zero temperature limit of quantum statistical mechanics using Quantum Monte Carlo simulations. We develop a Quantum Monte Carlo method in which one fixes the ground state energy as a parameter. The Hamiltonians we consider are of the form H = H-0 + lambda V with ground state energy E. For fixed H-0 and V. one can view E as a function of lambda whereas we view lambda as a function of E. We fix E and define a path integral Quantum Monte Carlo method in which a path makes no reference to the times (discrete or continuous) at which transitions occur between states. For fixed E we can determine lambda(E) and other ground state properties of H. (C) 2011 Elsevier BM. All rights reserved.