Nonanalytic contributions to the self-energy and the thermodynamics of two-dimensional Fermi liquids.

We calculate the entropy of a two-dimensional Fermi Liquid(FL) using a model with a contact interaction between fermions. We find that there are T 2 contributions to the entropy from interactions separate from those due to the collective modes. These T 2 contributions arise from non-analytic corrections to the real part of the selfenergy which may be calculated from the leading log dependence of the imaginary part of the self-energy through the Kramers-Kronig relation. We find no evidence of a breakdown in Fermi Liquid theory in 2D and conclude that FL in 2D are similar to 3D FL’s.