engleski

A consistent approach in relativistic random phase approximation

A fully consistent relativistic random phase approximation (RRPA) is investigated for giant resonances in finite nuclei. It can be concluded in the framework of the nucleon-meson field theory that a consistent treatment of RRPA built on the relativistic mean field (RMF) ground state has to include not only the positive energy particle-hole pairs, but also the pairs formed from the Dirac states and occupied Fermi states. A schematic model is introduced to understand the role of the Dirac state contributions from the pairs of Fermi to Dirac sea states. It is found that the main contribution of those states are through the exchange of the scalar meson, while the vector mesons play a negligible role. The static polarizability in isoscalar monopole modes is studied in a constrained RMF, which provides the energy inverse weighted sum rule. It is found that the sum rule is fulfilled only in the case where the Dirac state contributions are included.

relativistic random phase approximation

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