Quasiparticle properties in effective field theory

The quasiparticle concept is an important tool for the description of many-body systems. We study the quasiparticle properties for dilute Fermi systems with short-ranged, repulsive interactions using effective field theory. We calculate the proper self-energy contributions at order (k(F)/Lambda)(3), where A is the short-distance scale that sets the size of the effective range parameters and k(F) the Fermi momentum. The quasiparticle energy, width, and effective mass to O((k(F)/Lambda)(3)) are derived from the calculated self-energy. (C) 2002 Elsevier Science B.V. All rights reserved