Shell Model Monte Carlo method in the -formalism

The Shell model Monte Carlo (SMMC) method [1] was developed as an alternative to direct diagonalization in order to study low-energy nuclear properties. It was successfully applied to nuclear problems where large model spaces made diagonalization impractical. One calculates the thermal canonical expectation values of observables of few-body operators by representing the imaginary-time many-body evolution operator as a superposition of onebody propagators in fluctuating auxiliary fields. Thus, one recasts the Hamiltonian diagonalization problem as a stochastic integration problem.