Particle-hole interactions

M.G.E. Brand, Klaas Allaart, Willem H Dickhoff

Richard R. Chasman, William Ogle

Friedemann Queißer, Ralf Schützhold

Via the hierarchy of correlations, we study strongly interacting fermions on a lattice and derive a quantum Boltzmann equation describing their relaxation dynamics. Interestingly, in the strong-coupling limit, collisions between particles and holes dominate over particle-particle and hole-hole collisions -- in stark contrast to weakly interacting systems. Therefore, the relaxation towards equilibrium strongly depends on what kind of excitations (particles or holes or both) are present.

M. H. Urin

An attempt to formulate the optical model of particle-hole-type excitations (including giant resonances) is undertaken. The model is based on the Bethe--Goldstone equation for the particle-hole Green function. This equation involves a specific energy-dependent particle-hole interaction that is due to virtual excitation of many-quasiparticle configurations and responsible for the spreading effect. After energy averaging, this interaction involves an imaginary part. The analogy between the single-quasiparticle and particle-hole optical models is outlined.