Double Quantum Dots as Detectors of High-Frequency Quantum Noise in Mesoscopic Conductors

  • R. Aguado
  • L. P. Kouwenhoven
Conference paper
Part of the Lecture Notes in Physics book series (LNP, volume 547)


In this work we propose a measurement set-up for detecting quantum noise over a wide frequency range using inelastic transitions in a tunable two-level system as a detector. Recently, two device structures were realized that can be used as tunable two-level systems. In a superconducting single-electron transistor a Cooper-pair [1] and in a double quantum dot an electron [2] can make inelastic transitions between two discrete energy states. The transition rate for levels separated by an energy ∈, is a measure of the spectral density of the fluctuations in the enviroment at a frequency f = ∈/h. In our set-up the frequency-resolving detector consists of a double quantum dot which is capacitively coupled to the leads of a nearby mesoscopic conductor. The inelastic current through the double quantum dot is calculated in response to equilibrium and non-equilibrium current fluctuations in the nearby conductor, including vacuum fluctuations at very low temperatures. As a specific example, the fluctuations across a quantum point contact are discussed.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • R. Aguado
    • 1
    • 2
  • L. P. Kouwenhoven
    • 1
  1. 1.Department of Applied Physics and DIMESDelft University of TechnologyDelftThe Netherlands
  2. 2.Department of Physics and AstronomyRutgers UniversityPiscatawayUSA

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