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Detection of Quantum Noise from an Electrically-Driven Two-Level System

R. Deblock·E. Onac·L. Gurevich·L. P. Kouwenhoven
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Abstract

Quantum mechanics can strongly influence the noise properties of mesoscopic devices. To probe this effect we have measured the current fluctuations at high-frequency (5-90 GHz) using a superconductor-insulator-superconductor tunnel junction as an on-chip spectrum analyser. By coupling this frequency-resolved noise detector to a quantum device we can measure the high-frequency, non-symmetrized noise as demonstrated for a Josephson junction. The same scheme is used to detect the current fluctuations arising from coherent charge oscillations in a two-level system, a superconducting charge qubit. A narrow band peak is observed in the spectral noise density at the frequency of the coherent charge oscillations.

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R. Deblock, E. Onac, L. Gurevich, L. P. Kouwenhoven. 2003-10-08. Detection of Quantum Noise from an Electrically-Driven Two-Level System. https://doi.org/10.1126/science.1084175

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