Extension of the second random-phase approximation

D. Gambacurta, M. Grasso, F. Catara, and M. Sambataro
Phys. Rev. C 73, 024319 – Published 28 February 2006

Abstract

The second random-phase approximation (SRPA) is the simplest and most natural extension of the RPA. It enlarges the space of the elementary modes introduced to describe the collective states by adding 2 particle -2 hole excitations to the 1 particle -1 hole ones of the RPA. In deriving the SRPA equations, use is made, as in the RPA, of the so-called quasi-boson approximation (QBA) where expectation values in the ground state of the system are approximated by their values in the uncorrelated reference state. This, however, has been shown to imply a degree of approximation worse than that in the RPA. It is, therefore, necessary to improve the QBA by considering a reference state which contains some correlations. Having in mind to perform such calculations for realistic systems, we consider a simple extension of the SRPA in which the reference state contains 2 particle - 2 hole correlations. The quality of such an extension is tested by applying it to a solvable three-level model and found to be good.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
1 More
  • Received 4 October 2005

DOI:https://doi.org/10.1103/PhysRevC.73.024319

©2006 American Physical Society

Authors & Affiliations

D. Gambacurta, M. Grasso, F. Catara, and M. Sambataro

  • Dipartimento di Fisica ed Astronomia, Via Santa Sofia 64, I-95123 Catania, Italy, and INFN, Sezione di Catania, Via Santa Sofia 64, I-95123 Catania, Italy

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 73, Iss. 2 — February 2006

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review C

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×