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The Landau-Migdal Interaction


As a result of the symmetry properties of the nuclear force the form of the particle-hole interaction can be written as the sum of terms with different spin and isospin dependence. For the specific case of isospin symmetric nuclear matter the p-h force has the form [Ost92]

In the so-called Landau limit, which describes small excitations near the Fermi surface, the particle and hole momenta, and , are both near the Fermi momentum and thus roughly equal to each other in magnitude. Therefore, the interaction terms will only depend on the angle between and and can be expanded in terms of Legendre polynomials, . For very short range interactions only the first few terms in the expansion will be significant, and for contact interactions only the l=0 term is important. Therefore, for zero-range interactions the Landau-Migdal theory for effective p-h interactions is usually written as

where the radial dependence of the term is given by the nuclear charge distribution and is the inverse of the density of state, 302 MeV where is the Fermi momentum and is the quasiparticle effective mass.

Michael A. Lisa
Tue Apr 1 08:52:10 EST 1997