Conductance and thermopower fluctuations in interacting quantum dots

We model an interacting quantum dot of electrons by a Hamiltonian with random and all -to -all single -particle hopping (of root -mean -square strength t ) and two -particle interactions (of root -mean -square strength J ). For t << J , such a model has a regime exhibiting the nonquasiparticle physics of the Sachdev-Ye-Kitaev (SYK) model at temperatures E (coh) << T << J , and that of a renormalized Fermi liquid at T << E (coh), where E (coh)= t (2) / J . Extending earlier work has computed the mean thermoelectric properties of such a dot weakly coupled to two external leads, we compute the sample -to -sample fluctuations in the conductance and thermopower of such a dot, and describe several distinct regimes. In all cases, the effect of the SYK interactions is to reduce the strength of the sample -to -sample fluctuations. We also find that in the regime where the mean transport coefficients are determined only by the value of J at leading order, the sample -to -sample fluctuations can be controlled by the influence of the smaller t .