2012/09/30 by T. P. Purdy, R. W. Peterson, C. A. Regal
Physics and Astronomy · #quant-ph #cond-mat.mes-hall #physics.optics
paper · pdf · doi:10.1126/science.1231282
published as Science 339, 801 (2013) · 16 pages, 8 figures
arxiv created 2013/02/17 · arxiv updated 2013/02/19
The quantum mechanics of position measurement of a macroscopic object is typically inaccessible because of strong coupling to the environment and classical noise. Here we monitor a mechanical resonator subject to an increasingly strong continuous position measurement and observe a quantum mechanical backaction force that rises in accordance with the Heisenberg uncertainty limit. For our optically-based position measurements, the backaction takes the form of a fluctuating radiation pressure from the Poisson-distributed photons in the coherent measurement field, termed radiation pressure shot noise. We demonstrate a backaction force that is comparable in magnitude to the thermal forces in our system. Additionally, we observe a temporal correlation between fluctuations in the radiation force and in the position of the resonator.