title: Alleviation of the Fermion-sign problem by optimization of many-body wave functions.
abstract: We present a simple, robust, and highly efficient method for optimizing all parameters of many-body wave functions in quantum Monte Carlo calculations, applicable to continuum systems and lattice models. Based on a strong zero-variance principle, diagonalization of the Hamiltonian matrix in the space spanned by the wave function and its derivatives determines the optimal parameters. It systematically reduces the fixed-node error, as demonstrated by the calculation of the binding energy of the small but challenging C(2) molecule to the experimental accuracy of 0.02 eV.
authors.affiliation: Theory Center and Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Umrigar
authors.forename: Julien
authors.initials: J
authors.lastname: Toulouse
authors.forename: Claudia
authors.initials: C
authors.lastname: Filippi
authors.forename: S
authors.initials: S
authors.lastname: Sorella
authors.forename: R G
authors.initials: RG
authors.lastname: Hennig