Naslov
Collective multipole excitations based on correlated realistic nucleon-nucleon interactions

Autori
Paar, Nils ; Papakonstantinou, Panagiota ; Hergert, Heiko ; Roth, Robert

Izvornik
Physical Review C (0556-2813) 74 (2006);

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
nucleon-nucleon interactions; Hartree-Fock; collective excitations; RPA

Sažetak
We investigate collective multipole excitations for closed shell nuclei from ${; ; }; ; ^{; ; 16}; ; $O to ${; ; }; ; ^{; ; 208}; ; $Pb using correlated realistic nucleon-nucleon interactions in the framework of the random phase approximation (RPA). The dominant short-range central and tensor correlations are treated explicitly within the Unitary Correlation Operator Method (UCOM), which provides a phase-shift equivalent correlated interaction $\VO_{; ; \UCOM}; ; $ adapted to simple uncorrelated Hilbert spaces. The same unitary transformation that defines the correlated interaction is used to derive correlated transition operators. Using $\VO_{; ; \UCOM}; ; $ we solve the Hartree-Fock problem and employ the single-particle states as starting point for the RPA. By construction, the UCOM-RPA is fully self-consistent, i.e. the same correlated nucleon-nucleon interaction is used in calculations of the HF ground state and in the residual RPA interaction. Consequently, the spurious state associated with the center-of-mass motion is properly removed and the sum-rules are exhausted within $\pm$3$\%$. The UCOM-RPA scheme results in a collective character of giant monopole, dipole, and quadrupole resonances in closed-shell nuclei across the nuclear chart. For the isoscalar giant monopole resonance, the resonance energies are in agreement with experiment hinting at a reasonable compressibility. However, in the $1^-$ and $2^+$ channels the resonance energies are overestimated due to missing long-range correlations and three-body contributions.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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