We consider the possibility of measuring nonequilibrium properties of the current correlation functions at high temperatures (and small bias). Through the example of the third cumulant of the current $\left({\mathcal{S}}_3\right)$ we demonstrate that odd-order correlation functions represent nonequilibrium physics even at small external bias and high temperatures. We calculate ${\mathcal{S}}_3{=y(eV/T)e}^{2}I$ for a quasi-one-dimensional diffusive constriction. We calculate the scaling function y in two regimes: when the scattering processes are purely elastic and when the inelastic electron-electron scattering is strong. In both cases we find that y interpolates between two constants. In the low- (high-) temperature limit y is strongly (weakly) enhanced (suppressed) by the electron-electron scattering.

• Received 24 September 2002

DOI:https://doi.org/10.1103/PhysRevB.68.035302