Resumming the fermionic in-medium ladder diagrams to all orders

José A. Oller (University of Murcia)

Abstract: In the past I derived from QFT the generating functional of Green functions in a fermionic medium. Based on this many-body scheme I give an algebraic derivation from first principles of the purely diagrammatical method introduced by N. Kaiser [NPA860,411(2011)] to resum ladder diagrams for the calculation of the energy density in a fermionic environment including only the S-wave scattering length. A generalization of this result for any given fermion-fermion scattering matrix is provided. I also discuss its partial-wave expansion.

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