https://doi.org/10.1140/epja/i2008-10596-3
Regular Article - Theoretical Physics
Extended random-phase approximation with three-body ground-state correlations
1
Kyorin University School of Medicine, 181-8611, Mitaka, Tokyo, Japan
2
Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, F-91406, Orsay Cedex, France
* e-mail: tohyama@kyorin-u.ac.jp
Received:
17
March
2008
Accepted:
19
May
2008
Published online:
2
June
2008
An extended random-phase approximation (ERPA) which contains the effects of ground-state correlations up to a three-body level is applied to an extended Lipkin model which contains an additional particle-scattering term. Three-body correlations in the ground state are necessary to preserve the hermiticity of the Hamiltonian matrix of ERPA. Two approximate forms of ERPA which neglect the three-body correlations are also applied to investigate the importance of three-body correlations. It is found that the ground-state energy is little affected by the inclusion of the three-body correlations. On the contrary, three-body correlations for the excited states can become quite important.
PACS: 21.60.Jz Nuclear Density Functional Theory and extensions (includes Hartree-Fock and random-phase approximations) –
© Società Italiana di Fisica and Springer-Verlag, 2008
