Biplab Mahato (IFT)

In this talk, I will discuss four-Fermion contact interactions as effective field theories of strongly interacting Fermionic systems in 2+1 and 3+1 dimensions. The non-perturbative effects, specifically the formation and dissociation of bound states from the constituent fermions, can be captured by mean-field approximations. Here, I will focus on the fluctuations on top of the mean field to study the correlations. In particular, I will talk about two effects that arise: the reappearance of bound states at high momenta relative to the medium and the Landau damping modes. The effect of these on the thermodynamics, which can be captured by the Beth-Uhlenbeck approach, is not negligible. Finally, as an application, baryons are constructed as a quark-diquark pair using the spectral function of the diquarks.