APS
Singular corrections to the Fermi liquid theory
Andrey V. Chubukov, Dmitrii L. Maslov
Abstract
We show that the singularities in the dynamical bosonic response functions of a two-dimensional Fermi liquid give rise to universal nonanalytic corrections to the results of the Fermi-liquid theory. In particular, we find a ${T}^{2}$ term in the specific heat, linear-in-$T$ terms in the effective mass and in the uniform spin susceptibility ${\ensuremath{\chi}}_{s}(Q=0,T),$ and $|Q|$ term in ${\ensuremath{\chi}}_{s}(Q,T=0).$ The existence of these terms has been the subject of recent controversy, which is resolved in this paper. We present exact expressions for all nonanalytic terms to second order in a generic interaction $U(Q)$ and show that the nonanalytic terms originate exclusively from forward- and backward-scattering of particles with zero total momentum.