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Detector's quantum backaction effects on a mesoscopic conductor and fluctuation‐dissipation relation
Author(s) -
Magazzù Luca,
Valenti Davide,
Spagnolo Bernardo,
Martin Thierry,
Falci Giuseppe,
Paladino Elisabetta
Publication year - 2017
Publication title -
fortschritte der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.469
H-Index - 71
eISSN - 1521-3978
pISSN - 0015-8208
DOI - 10.1002/prop.201600059
Subject(s) - physics , mesoscopic physics , quantum point contact , quantum , langevin equation , quantum dissipation , dissipation , quantum mechanics , detector , quantum fluctuation , quantum electrodynamics , quantum well , optics , laser
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.