Constructing variational principles
We describe a systematic procedure for the construction of variational principles for the variational estimation of an extremely wide class of functionals F(,). The quantities are well defined but not known exactly because the equations defining the set are not solvable exactly. The procedure is illustrated for F, the off-diagonal matrix element 1W2 of an arbitrary Hermitian linear operator W, for 1 and 2 nondegenerate normalized bound-state eigenfunctions of the same Hamiltonian with a specified relative phase. © 1973 The American Physical Society.
Publication Source (Journal or Book title)
Physical Review A
Gerjuoy, E., Rau, A., & Spruch, L. (1973). Constructing variational principles. Physical Review A, 8 (2), 662-665. https://doi.org/10.1103/PhysRevA.8.662