| speaker: | Mireille Lavagna Grenoble, France |
| time: | Th., 16.08, 16:00-17:00 |
Recent experiments [1] realized at the Weizmann Institute of Science allow one to investigate the phase evolution of the transmission phase shift through a quantum dot (QD) as a function of the gate voltage applied to the dot and of the coupling strength of the dot to the leads. The traversal phase is determined using a quantum interferometer consisting of an Aharonov-Bohm (AB) ring with the quantum dot embedded in one of the two arms. The experimental results are in contradiction with the theoretical prediction made in Kondo bulk systems more than three decades ago where a value of pi/2 was found. We propose a theoretical interpretation of these results [2] based on scattering theory off an artificial atom as appropriate to describe the QD. Our results are in good quantitative agreement with the measurements performed by AB interferometry for both the conductance and the phase shift in two different regimes of the coupling to the leads.
[1] Y. Ji, M. Heiblum, D. Sprinzak, D. Mahalu, and H. Shtrikman, Science 290, 779 (2000); Y. Ji, M. Heiblum, and H. Shtrikman, Phys. Rev. Lett. 88, 076601 (2002).
[2] A. Jerez, P. Vitushinsky, and M. Lavagna, Phys. Rev. Lett. 95, 127203 (2005).