Göttingen 1997 – scientific programme

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HK: Hadronen und Kerne

HK 52: Kernkräfte, Kernreaktionen II

HK 52.5: Talk

Wednesday, March 26, 1997, 18:15–18:30, HS F

Towards a fully self-consistent nucleon spectral function — •F. de Jong and H. Lenske — Institut für Theoretische Physik, Universität Giessen

Commonly in nuclear many-body calculations the quasi-particle approximation is used. This procedure ignores the energy dependence of the self-energy and fixes its value to the one at the quasi-particle peak of the spectral function while setting the imaginary part to zero. This then gives a spectral function which is a δ-function in the energy variable. If most strength of the spectral function is centered around the quasi-particle peak this is expected to be a good approximation. However, it does limit the self-consistency of the calculated self-energy, a requirement needed in the proofs of general conservation laws like energy conservation and thermo-dynamical consistency. We present a method which goes beyond the quasi-particle approximation: using a suitable approximation scheme for spectral function that does include off-shell contributions we calculate a self-consistent solution for the self-energy which incorporates off-shell effects. First results will be presented, focussing on differences generated by these off-shell effects.

^* unterstützt durch BMBF und GSI Darmstadt.