Projects per year
Abstract
Quantum mechanics sets a limit for the precision of continuous measurement of the position of an oscillator. We show how it is possible to measure an oscillator without quantum backaction of the measurement by constructing one effective oscillator from two physical oscillators. We realize such a quantum mechanicsfree subsystem using two micromechanical oscillators, and show the measurements of two collective quadratures while evading the quantum backaction by 8 decibels on both of them, obtaining a total noise within a factor of 2 of the full quantum limit. This facilitates the detection of weak forces and the generation and measurement of nonclassical motional states of the oscillators. Moreover, we directly verify the quantum entanglement of the two oscillators by measuring the Duan quantity 1.4 decibels below the separability bound.
Original language  English 

Pages (fromto)  625629 
Number of pages  23 
Journal  Science (New York, N.Y.) 
Volume  372 
Issue number  6542 
DOIs  
Publication status  Published  7 May 2021 
MoE publication type  A1 Journal articlerefereed 
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Quantum squeezing and entanglement in microwave optomechanical systems
OckeloenKorppi, C.
01/09/2017 → 31/08/2020
Project: Academy of Finland: Other research funding

Quantum mechanics of mechanics
Sillanpää, M., Rej, E., Mishra, H., Liu, Y., Mercier de Lepinay, L., Damskägg, E., Välimaa, A. & Wang, C.
01/09/2017 → 31/08/2021
Project: Academy of Finland: Other research funding