Higher-order Fermi-liquid corrections for thermo-electric transport through an Anderson impurity

There has been an important progress recently in the Fermi-liquid theory for Kondo systems away from half-filling [1,2]. That clarifies what are the essential parameters that determine the non-equilibrium impurity Green's function G(ω,T,eV) at low frequencies ω, temperatures T, and bias voltages eV, in the particle-hole asymmetric case. The asymptotically exact Green's function away from half-filling are shown to be determined, up to order ω², T², and (eV)², by the static linear susceptibilities of the impurity occupation numbers and the corresponding non-linear susceptibilities that are defined with respect to the equilibrium ground state. In the present work, we apply a microscopic description that uses the Ward identities [2] to thermo-electric transport of quantum dots and dilute magnetic alloys. Using also the NRG approach, we explore how the three-body correlations that enter through the non-linear susceptibilities contribute to thermal conductivity at zero and finite magnetic fields.
[1] M. Filippone, C. Moca, A. Weichselbaum, J. von Delft, and C. Mora, PRB 98, 075404 (2018); C. Mora, C. Moca, J. von Delft, and G.Zaránd, PRB 92, 075120 (2015).
[2] A. Oguri and A. C. Hewson, PRL 120, 126802 (2018); PRB 97, 043508 (2018); PRB 97, 035435 (2018); PRB 98, 079905(E)(2018).