Current Noise through a Kondo Quantum Dot in a $\mathrm{SU}(N)$ Fermi Liquid State

The current noise through a mesoscopic quantum dot is calculated and analyzed in the Fermi liquid regime of the $\mathrm{SU}(N)$ Kondo model. The results connect the Johnson-Nyquist noise to the shot noise for an arbitrary ratio of voltage and temperature, and show that temperature corrections are sizable in the usual experiments. For the experimentally relevant SU(4) case, quasiparticle interactions are shown to increase the shot noise.

Figure 1

Diagrams for the noise appearing in the first and second order expansions in the inelastic Hamiltonian Eq. (8). (c) and (d) give identical contributions. For (f), the three-lines bubble can alternatively dress the bottom Green’s function. $\alpha$, $\beta$, and $\gamma$ denote spins.

Figure 2

Generalized Fano factor $F$ from Eq. (14) as a function of $eV/T$ (full lines) for SU(2) and SU(4). Dotted lines are shot-noise limits.