Fractional shot noise of an SU(N) Kondo system.

On the active periods of nonlinear Shot Noise

We have investigated the spectral density of shot noise for the system in Kondo regime irradiated with ac fields on the QD and the two terminals. In the low temperature, strong coupling, and large charging energy regime, the correlation effects influence electron transport significantly. The external ac fields split the Kondo peak to form side peaks, and the locations of the side peaks are dependent on the frequency considerably. The differential shot noise in the Kondo regime is very different from that in the non-interacting QD system. The Kondo effect and photon-assisted tunneling destroy the symmetry of shot noise. Both super-Poissonian and sub-Poissonian shot noise exist in Kondo regime. The asymmetric structure is found more evident in the derivative of shot noise for the photon-electron pumping case.

We have investigated the spectral density of shot noise for an ultra-small quantum dot(QD) system in the Coulomb blockade regime when irradiated with microwave fields (MWFs) by employing a nonequilibrium Green’s function technique. The shot noise is sensitive to Coulomb interaction, and the photon-assisted Coulomb blockade behaviour strongly modifies the mesoscopic transport. We have calculated the first and second derivatives of shot noise in the strong and weak coupling regimes to compare the theoretical results with existing experimental results. In the strong coupling regime, the first and second derivatives of shot noise display Fano type peak-valley structures around the charging channel 2E c due to Coulomb interaction. When the magnitudes of the MWFs are sufficiently large, the system displays channel blockade due to photon irradiation. The photon-assisted and Coulomb blockade steps in the noise — as well as the resonant behaviour in the differential noise — are smeared by increasing temperature. The Coulomb interaction suppresses the shot noise, but the ac fields can either suppress the shot noise(balanced case) or enhance the shot noise(unbalanced case). The suppression of shot noise caused by ac fields in the balanced case is greater than that caused by Coulomb interaction in our system. Super-Poissonian shot noise may be induced due to the compound effects of strong Coulomb interaction and photon absorption-emission processes.

We study differential shot noise in mesoscopic diffusive normal-superconducting (NS) heterostructures at finite voltages where nonlinear effects due to the superconducting proximity effect arise. A numerical scattering-matrix approach is adopted. Through an NS contact, we observe that the shot noise shows a reentrant dependence on voltage due to the superconducting proximity effect but the differential Fano factor stays approximately constant. Furthermore, we consider differential shot noise in the structures where an insulating barrier is formed between normal and superconducting regions and calculate the differential Fano factor as a function of barrier height.

We consider Nonlinear Shot Noise systems in which external shots hit the system following an arbitrary Poissonian inflow and, after impact, dissipate to zero governed by an arbitrary nonlinear decay mechanism. The “standard” Shot Noise process tracks the shots aggregate (at any given time) and is non-Markov. In this letter we shift from aggregate dynamics to maximal dynamics —tracking the magnitude of the largest shot present in the system (at any given time). This yields a class of stochastic processes which: i) display a wide spectrum of random decay-surge evolutionary patterns; ii) are intrinsically nonlinear in both their decay and surge mechanisms; but yet, iii) turn out to be Markovian and analytically tractable. A detailed quantitative statistical analysis of this class of processes is presented.

The interplay of intralead and dot-lead Coulomb electrons on shot noise in the Kondo regime

Conductance and shot noise of inelastic tunneling through a quantum dot in the Kondo regime

The maximal process of nonlinear shot noise

Nonlinear shot noise, memory systems, and all-time hit parades

The shot noise of a quantum dot (QD) coupled to the ferromagnetic terminals under the perturbation of microwave fields (MWFs) in the Kondo regime has been derived by employing the nonequilibrium Green's function approach. The photon-assisted shot noise associated with the spin-polarized electron tunneling in the Kondo regime has been derived and calculated to reveal significant results for spintronics. The modification of shot noise induced by the polarization angle and spin-polarized linewidths exhibits clearly. The Fano factor displays the photon-assisted effect more efficiently for the circumstance of smaller linewidths. The shot noise is suppressed and enhanced by the MWFs, and it shows sub-Poissonian and super-Poissonian features.

Transport through quantum dots in the Kondo regime obeys an effective low-temperature theory in terms of weakly interacting quasiparticles. Despite the weakness of the interaction, we find that the backscattering current and hence the shot noise are dominated by two-quasiparticle scattering. We show that the simultaneous presence of one- and two-quasiparticle scattering results in a universal average charge 5/3e as measured by shot-noise experiments. An experimental verification of our prediction would constitute a most stringent test of the low-energy theory of the Kondo effect.

The shot noise in the current through a quantum dot is calculated as a function of voltage from the high-voltage Coulomb-blockaded regime to the low-voltage Kondo regime. Using several complementary approaches, it is shown that the zero-frequency shot noise (scaled by the voltage) exhibits a nonmonotonic dependence on voltage, with a peak around the Kondo temperature. Beyond giving a good estimate of the Kondo temperature, it is shown that the shot noise yields additional information on the effects of electronic correlations on the local density of states in the Kondo regime, unaccessible in traditional transport measurements.

AC shot noise through a quantum dot in the Kondo regime

Effect of magnetic fields on the shot noise of a quantum dot with Luttinger leads

The shot noise of a strongly correlated quantum dot coupled to the Luttinger liquid leads