Bidirectional Single-Electron Counting and the Fluctuation Theorem

Physical review. B, Condensed matter (Impact Factor: 3.66). 08/2009; DOI: 10.1103/PhysRevB.81.125331
Source: arXiv

ABSTRACT We investigate theoretically and experimentally the full counting statistics of bidirectional single-electron tunneling through a double quantum dot in a GaAs/GaAlAs heterostructure and compare with predictions of the fluctuation theorem (FT) for Markovian stochastic processes. We observe that the quantum point contact electrometer used to study the transport induces nonequilibrium shot noise and dot-level fluctuations and strongly modifies the tunneling statistics. As a result, the FT appears to be violated. We show that it is satisfied if the back-action of the electrometer is taken into account, and we provide a quantitative estimate of this effect. Comment: 4pages, 2figures

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    ABSTRACT: We study single-electron transport through a double quantum dot (DQD) monitored by a capacitively coupled quantum point-contact (QPC) electrometer. We derive the full counting statistics for the coupled DQD - QPC system and obtain the joint probability distribution of the charges transferred through the DQD and the QPC consistent with the fluctuation theorem for four terminal system. For the two-terminal DQD system, the FT is not necessarily satisfied. It is due to the back action caused by the shot noise of the QPC, and the FT for the DQD is modified with an “effective temperature”.
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