Breakdown of Landau Fermi liquid properties in the 2D BOSON-FERMION model

We study the normal state spectral properties of the fermionic excitations in the Boson-Fermion model. The fermionic single particle excitations show a flattening of the dispersion as the Fermi vector k F is approached from below, forshadowing a Bogoliubov spectrum of a superconducting ground state. The width of the quasiparticle excitations near k F increases monotonically as the temperature is lowered. In the fermionic distribution function this temperature dependence is manifest in a strong modification of n(k) in a small region below k F , but a nearly T independant n(k F ).