When measuring quantum mechanical properties of charge transport in mesoscopic conductors, backaction effects occur. We consider a measurement setup with an elementary quantum circuit, composed of an inductance and a capacitor, as detector of the current flowing in a nearby quantum point contact. A quantum Langevin equation for the detector variable including backaction effects is derived. Differences with the quantum Langevin equation obtained in linear response are pointed out. In this last case, a relation between fluctuations and dissipation is obtained, provided that an effective temperature of the quantum point contact is defined.
Magazzù, L., Valenti, D., Spagnolo, B., Martin, T., Falci, G., Paladino, E. (2017). Detector's quantum backaction effects on a mesoscopic conductor and fluctuation-dissipation relation. FORTSCHRITTE DER PHYSIK, 65(6-8), 1-10 [10.1002/prop.201600059].
Detector's quantum backaction effects on a mesoscopic conductor and fluctuation-dissipation relation
VALENTI, Davide;SPAGNOLO, Bernardo;
2017-01-01
Abstract
When measuring quantum mechanical properties of charge transport in mesoscopic conductors, backaction effects occur. We consider a measurement setup with an elementary quantum circuit, composed of an inductance and a capacitor, as detector of the current flowing in a nearby quantum point contact. A quantum Langevin equation for the detector variable including backaction effects is derived. Differences with the quantum Langevin equation obtained in linear response are pointed out. In this last case, a relation between fluctuations and dissipation is obtained, provided that an effective temperature of the quantum point contact is defined.File | Dimensione | Formato | |
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