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Theses

Coupling between two mesoscopic systems towards the measurement of noise

Abstract : The central topic of this thesis is the physics of noise: the Fourier transform of the current-current correlation function in time. We examine situations where the noise generated by a given mesoscopic circuit affects the behavior of another mesoscopic circuit. In the first part of this study, the noise source is unknown, and the mesoscopic circuit which is capacitively coupled to it acts as a detector of high frequency noise. In our case, the detector consists of a normal metal-superconductor junction where electron transport occurs via quasiparticle tunneling, or more interestingly, via Andreev reflection processes. The theory of dynamical Coulomb blockade is employed in order to compute the dc current which flows into the
detector circuit, providing information on high frequency noise. In the second part of this thesis, the noise source is known: it consists of a Hall bar with a quantum point contact, for which anomalous current voltage and noise characteristics are established when the Hall bar is placed in the fractional quantum Hall regime. A quantum dot connected to leads, which is placed next to this point contact, acquires a finite linewidth when the current fluctuates, and acts as a detector of charge noise. We compute the dephasing rate in the weak and strong backscattering regime, describing both case of unscreened and screened Coulomb interaction between
the Hall bar and the quantum dot.
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https://tel.archives-ouvertes.fr/tel-00175563
Contributor : Thi Kim Thanh Nguyen <>
Submitted on : Friday, September 28, 2007 - 3:59:58 PM
Last modification on : Thursday, September 13, 2018 - 12:08:03 PM
Long-term archiving on: : Thursday, April 8, 2010 - 8:47:11 PM

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  • HAL Id : tel-00175563, version 1

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Thi Kim Thanh Nguyen. Coupling between two mesoscopic systems towards the measurement of noise. Condensed Matter [cond-mat]. Université de la Méditerranée - Aix-Marseille II, 2007. English. ⟨tel-00175563⟩

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