Adiabatic state preparation of correlated wave functions with nonlinear scheduling functions and broken-symmetry wave functions

Abstract

Adiabatic state preparation (ASP) can generate the correlated wave function by simulating the time evolution of wave function under the time-dependent Hamiltonian that interpolates the Fock operator and the full electronic Hamiltonian. However, ASP is inherently unsuitable for studying strongly correlated systems, and furthermore practical computational conditions for ASP are unknown. In quest for the suitable computational conditions for practical applications of ASP, we performed numerical simulations of ASP in the potential energy curves of N₂, BeH₂, and in the C_2v quasi-reaction pathway of the Be atom insertion to the H₂ molecule, examining the effect of nonlinear scheduling functions and the ASP with broken-symmetry wave functions with the S² operator as the penalty term, contributing to practical applications of quantum computing to quantum chemistry. Eventually, computational guidelines to generate the correlated wave functions having the square overlap with the complete-active space self-consistent field wave function close to unity are discussed.

Adiabatic state preparation (ASP) can generate correlated wave functions for quantum chemical calculations, but is inherently unsuitable for studying strongly correlated systems. Here, the authors perform numerical simulations of ASP for the ground state wave functions of molecules with strongly correlated electrons and propose practical conditions for preparation of close-to-exact correlated wave functions.