Latest documents http://publikationen.ub.uni-frankfurt.de/index/index/ Fri, 30 Apr 2010 12:16:45 +0200 Fri, 30 Apr 2010 12:16:45 +0200 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/7718 In this thesis, we study the properties of excitations in the systems of interacting fermions. These excitations can be bosonic such as collective modes which we handle in the first part of this thesis or fermionic like quasi particles and quasi holes. One of the important points, to investigate the excitations is their damping which corresponds to their life-time in the system. This thesis consists of two parts, where in both parts, we use the field-theoretical methods to examine the problem. Peyman Pirooznia doctoralthesis http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/7718 Fri, 30 Apr 2010 12:16:45 +0200