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On the energy-shell contributions of the three-particle~-~ three-hole excitations

A. Mariano·F. Krmpotić·A. F. R. de Toledo Piza
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Abstract

The response functions for the extended second and third random phase approximation are compared. A second order perturbation calculation shows that the first-order amplitude for the direct $3p3h$ excitation from the ground state cancels with those that are engendered by the $1p1h$-$3p3h$ coupling. As a consequence nonvanishing $3p3h$ effects to the $1p1h$ response involve off energy shell renormalization only. On shell $3p3h$ processes are absent.

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A. Mariano, F. Krmpotić, A. F. R. de Toledo Piza. 1994-01-14. On the energy-shell contributions of the three-particle~-~ three-hole excitations. https://doi.org/10.1103/physrevc.49.1949

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