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Updated: Jun 5, 2026

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry
Published on: August 1, 2017
Planck spectroscopy and quantum noise of microwave beam splitters
M Mariantoni1, E P Menzel, F Deppe
1Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, D-85748 Garching, Germany. matmar@physics.ucsb.edu
Abstract:
We use a correlation function analysis of the field quadratures to characterize both the blackbody radiation emitted by a 50 Ω load resistor and the quantum properties of two types of beam splitters in the microwave regime. To this end, we first study vacuum fluctuations as a function of frequency in a Planck spectroscopy experiment and then measure the covariance matrix of weak thermal states. Our results provide direct experimental evidence that vacuum fluctuations represent the fundamental minimum quantum noise added by a beam splitter to any given input signal.
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