On the Origin and the Amplitude of <i>T</i> ‐Square Resistivity in Fermi Liquids

In 1937, Baber, Landau and Pomeranchuk postulated that collisions between electrons generates a contribution to the electric resistivity of metals with distinct T$^2$ temperature dependence. The amplitude this term is small in common metals, but dominant hosting either heavy carriers or low concentration them. link dependence size scattering phase space straightforward, not microscopic source dissipation. To explain how electron-electron lead momentum leak, Umklapp events multiple electron reservoirs have been invoked. This interpretation challenged by number experimental observations: persistence T-square dilute (in which two mechanisms are irrelevant), successful extension Kadowaki-Woods scaling observation size-dependent thermal ($T/\kappa$) its Wiedemann-Franz (WF) correlation electrical resistivity. paper argues much insight provided case normal liquid $^3$He where energy diffusivity driven fermion-fermion collisions. share scaling. Thus, ubiquitous ultimately stems from Fermi-liquid diffusivity.