Since 1980s mesoscopic conductors have been serving as an ideal test bed to investigate quantum scattering problems, because the quantum transport through a single site can be probed by electric measurements in a tunable way. Usually, researchers mainly investigate the current (or the conductance) that is the average number of electrons that pass through the system for a finite time. On the other hand, the fluctuation of the current ("shot noise"), namely the fluctuation of the number of electrons passing through it, conveys us very unique information. Here we discuss how we learn the details of the Kondo effect by using the shot noise measurement [1, 2]. We discuss the shot noise in a carbon nanotube quantum dot in the SU(2) Kondo regime and SU(4) Kondo regime , which precisely clarifies an interesting feature of this typical quantum many body effect in the nonequilibrium regime.
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. M. Ferrier, T. Arakawa, R. Fujiwara, T. Hata, K. Kobayashi, R. Deblock, R. Delagrange, H. Bouchiat, R. Sakano, A. Oguri (unpublished).