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arXiv · 1809.06470

Squeezed vacuum used to accelerate the search for a weak classical signal

M. Malnou·D. A. Palken·B. M. Brubaker·Leila R. Vale·Gene C. Hilton·K. W. Lehnert
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Abstract

Many experiments that interrogate fundamental theories require detectors whose sensitivities are limited by the laws of quantum mechanics. In cavity-based searches for axionic dark matter, vacuum fluctuations in the two quadratures of the cavity electromagnetic field limit the sensitivity to an axion-induced field. In an apparatus designed to partially mimic existing axion detectors, we demonstrate experimentally that such quantum limits can be overcome through the use of squeezed states. By preparing a microwave cavity in a squeezed state and measuring just the squeezed quadrature, we enhance the spectral scan rate by a factor of $2.12 \pm 0.08$. This enhancement is in excellent quantitative agreement with a theoretical model accounting for both imperfect squeezing and measurement.

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M. Malnou, D. A. Palken, B. M. Brubaker, Leila R. Vale, Gene C. Hilton, K. W. Lehnert. 2018-09-17. Squeezed vacuum used to accelerate the search for a weak classical signal. https://doi.org/10.1103/physrevx.9.021023

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