Thermodynamics of a Fermi Liquid beyond the Low-Energy Limit (original) (raw)

We consider the non-analytic temperature dependences of the specific heat coefficient, C(T )/T , and spin susceptibility, χs (T ) , of 2D interacting fermions beyond the weak-coupling limit. We demonstrate within the Luttinger-Ward formalism that the leading temperature dependences of C(T )/T and χs(T ) are linear in T , and are described by the Fermi liquid theory. We show that these temperature dependences are universally determined by the states near the Fermi level and, for a generic interaction, are expressed via the spin and charge components of the exact backscattering amplitude of quasi-particles. We compare our theory to recent experiments on monolayers of He 3 .