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SYQD: Quantum decoherence in solid state physics

SYQD 2: Quantum Decoherence in Solid State Physics II

SYQD 2.1: Talk

Tuesday, March 25, 2003, 17:30–17:45, HSZ/01

Dephasing times in nearly-isolated quantum dots — •Karsten Held¹, Eli Eisenberg², and Boris L. Altshuler² — ¹Max-Planck Institut für Festkörperphysik, Stuttgart — ²Princeton University, Princeton, NJ 08544

The dephasing mechanism due to electron-electron interactions is substantially modified if the electrons are confined to a quantum dot, leading even to the prediction of a diverging dephasing time at a finite temperature [1]. From magnetoconductance measurements in nearly-isolated quantum dots [2] we are able to calculate dephasing times within the framework of random matrix theory, Master equation, and a phenomenological description of the dephasing time [3]. These dephasing times, turn out to depend on the mean level spacing and to be significantly enhanced as compared with the case of open quantum dots. The limited experimental data available is, within the statistical uncertainties, consistent with [1].

[1] B.L. Altshuler et al., Phys. Rev. Lett. 78, 2803 (1997).

[2] J. A. Folk, et al., Phys. Rev. Lett. 87, 206802 (2001).

[3] E. Eisenberg, K. Held, and B. L. Altshuler, Phys. Rev. Lett. 88, 136801 (2002).