Extended RPA with ground-state correlations in a solvable model

Abstract

The ground states and excited states of the Lipkin model hamiltonian are calculated using a new theoretical approach which has been derived from an extended time-dependent Hartree-Fock theory known as the time-dependent density-matrix theory (TDDM). TDDM enables us to calculate correlated ground states, and its small amplitude limit (STDDM), which is a version of extended RPA theories based on a correlated ground state, can be used to calculate excited states. It is found that this TDDM plus STDDM approach gives much better results for both the ground states and the excited states than the Hartree-Fock ground state plus RPA approach.

4 pages, 4 figures

References in corpus (3)

• Spurious modes in extended RPA theories
• Extended RPA with ground-state correlations
• Eigenstates of the time-dependent density-matrix theory

Cited by in corpus (8)

• Progress in Many Body Theory with the Equation of Motion method. Time dependent Density Matrix meets Self-Consistent RPA. Applications to solvable Models
• Self-Consistent RPA from a Coupled Cluster Wave Function Perspective
• Truncation scheme of time-dependent density-matrix approach
• Density-matrix formalism with three-body ground-state correlations
• Truncation scheme of time-dependent density-matrix approach II
• Self-Consistent RPA based on a Many-Body Vacuum
• Truncation scheme of time-dependent density-matrix approach III
• Reproduction of exact solutions of Lipkin model by nonlinear random-phase approximation