Quantum noise in carbon nanotubes as a probe of correlations in the Kondo regime

TL;DR

This paper reviews how quantum noise measurements in carbon nanotube quantum dots reveal detailed insights into Kondo correlations and many-body interactions beyond linear transport regimes.

Contribution

It presents a comprehensive review of recent experimental work on probing Kondo correlations via quantum noise in carbon nanotubes, highlighting new insights into interaction effects.

Findings

Quantum noise measurements reveal interaction effects in Kondo regimes.

Noise spectra provide information on the dynamics of Kondo correlated states.

Experimental techniques enable probing of high-frequency Kondo phenomena.

Abstract

Most of the time, electronic excitations in mesoscopic conductors are well described, around equilibrium, by non-interacting Landau quasi-particles. This allows a good understanding of the transport properties in the linear regime. However, the role of interaction in the non-equilibrium properties beyond this regime has still to be established. A paradigmatic example is the Kondo many body state, which can be realized in a carbon nanotube (CNT) quantum dot for temperatures below the Kondo temperature $T_K$. As CNT possess spin and orbital quantum numbers, it is possible to investigate the twofold degenerate SU(2) Kondo effect as well as the four fold degenerate SU(4) state by tuning the degeneracies and filling factor. This article aims at providing a comprehensive review on our recent works on the Kondo correlations probed by quantum noise measurement both at low and high frequencies and demonstrate how current noise measurements yield new insight on interaction effects and dynamics of a Kondo correlated state.