Seminar on Theoretical Nuclear Physics

23.01.14 16:15

Single-particle potential from resummed fermionic ladder diagrams

Norbert Kaiser (TU München)


For a system of fermions with a short-range interaction proportional to the scattering length a the in-medium ladder diagrams are resummed to all orders.
In the strong coupling limit a \to \infty the value \xi_n = 0.507 is obtained for the normal Bertsch parameter. Applications to the neutron matter equation of state at low densities are discussed. In addition to the energy per particle E(k_f), the complex single-particle potential U(p,k_f)+i W(p,k_f) inside and outside the Fermi sphere is calculated through a first functional derivative.
The Hugenholtz-Van-Howe theorem for U(p,k_f) is satisfied for the present non-perturbative resummation. The imaginary single-particle potential W(p,k_f) vanishes linearly at the Fermi surface, providing thus a counterexample to the common quadratic behavior.


Category: Kernphysik