Models of mesoscopic time-resolved current detection

Adam Bednorz and Wolfgang Belzig
Phys. Rev. B 81, 125112 – Published 12 March 2010

Abstract

Quantum transport in mesoscopic conductors is essentially governed by the laws of quantum mechanics. One of the major open questions of quantum mechanics is what happens if noncommuting observables are measured simultaneously. Since current operators at different times do not commute, the high-frequency correlation functions of the current are realization of this fundamental quantum question. We formulate this problem in the context of measurements of finite-frequency current cumulants in a general quantum point contact, which are the subject to ongoing experimental effort. To this end, we present two models of detectors that correspond to a weak time-resolved measurement of the electronic current in a mesoscopic junction. In both cases, the backaction of the detector leads to observable corrections to the current correlations functions involving the so-called noise susceptibilities. As a result, we propose a reinterpretation of environmental corrections to the finite-frequency cumulants as inevitable effect resulting from basic quantum mechanical principles. Finally we make concrete predictions for the temperature, voltage, and frequency dependence of the third cumulant, which could be verified directly using current experimental techniques.

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  • Received 27 January 2010

DOI:https://doi.org/10.1103/PhysRevB.81.125112

©2010 American Physical Society

Authors & Affiliations

Adam Bednorz1,2 and Wolfgang Belzig1

  • 1Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany
  • 2University of Warsaw, Hoża 69, PL-00681 Warsaw, Poland

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Issue

Vol. 81, Iss. 12 — 15 March 2010

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