Effects of ground-state correlations on magnetic dipole excitations in $^{40}$ CaEffects of ground-state correlations on magnetic dipole excitations in $^{40}$Ca

M. Tohyama

The effects of ground-state correlations on the magnetic dipole excitations in $^{40}$ Ca are studied using an extended random phase approximation (ERPA) derived from the time-dependent density-matrix theory. Comparison is made with other extended RPA approaches, the renormalized RPA, the self-consistent RPA and the extended second RPA which also include the effects of ground-state correlations. It is pointed out that direct excitations from two particle - two hole space which are properly treated in ERPA cause strong magnetic dipole transitions in $^{40}$ Ca.The effects of ground-state correlations on the magnetic dipole excitations in $^{40}$Ca are studied using an extended random phase approximation (ERPA) derived from the time-dependent density-matrix theory. Comparison is made with other extended RPA approaches, the renormalized RPA, the self-consistent RPA and the extended second RPA which also include the effects of ground-state correlations. It is pointed out that direct excitations from two particle - two hole space which are properly treated in ERPA cause strong magnetic dipole transitions in $^{40}$Ca.

arXiv:2009.02014Sep 4, 20200 citations

Extended RPA with ground-state correlations in a solvable model

Satoshi Takahara, M. Tohyama, Peter Schuck

The ground states and excited states of the Lipkin model Hamiltonian are calculated using a new theoretical approach that has been derived from an extended time-dependent Hartree-Fock theory known as the time-dependent density-matrix (TDDM) theory. TDDM theory 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.The ground states and excited states of the Lipkin model Hamiltonian are calculated using a new theoretical approach that has been derived from an extended time-dependent Hartree-Fock theory known as the time-dependent density-matrix (TDDM) theory. TDDM theory 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.

arXiv:nucl-th/0408042Physical Review CNov 19, 200419 citations

Towards a variational theory for RPA-like correlations and fluctuations

J. Dukelsky, Peter Schuck

Nuclear Physics AApr 1, 199093 citations

Effects of ground-state correlations on magnetic dipole excitations in

^{40}

The effects of ground-state correlations on the magnetic dipole excitations in

^{40}

Ca are studied using an extended random phase approximation (ERPA) derived from the time-dependent density-matrix theory. Comparison is made with other extended RPA approaches, the renormalized RPA, the self-consistent RPA and the extended second RPA which also include the effects of ground-state correlations. It is pointed out that direct excitations from two particle - two hole space which are properly treated in ERPA cause strong magnetic dipole transitions in

^{40}

Ca.