Green's function method with energy-independent vertex functions
Date
1996
Authors
Tsay Tzeng S.Y.
Kuo T.T.S.
Tzeng Y.
Geyer H.B.
Navratil P.
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Abstract
In conventional Green's function methods the vertex function T is generally energy dependent. However, a model-space Green's function method where the vertex function is manifestly energy independent can be formulated using energy-independent effective interaction theories based on folded diagrams and/or similarity transformations. This is discussed in general and then illustrated for a 1p1h model-space Green's function applied to a solvable Lipkin many-fermion model. The poles of the conventional Green's function are obtained by solving a self-consistent Dyson equation and model space calculations may lead to unphysical poles. For the energy-independent model-space Green's function only the physical poles of the model problem are reproduced and are in satisfactory agreement with the exact excitation energies.
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Citation
Physical Review C - Nuclear Physics
53
3
53
3