2020/09/30 by Laure Mercier de Lépinay, Caspar F. Ockeloen-Korppi, Matthew J. Woolley +1 · 1 citation
Computer Science · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Limit (mathematics) #Measure (data warehouse) #Mechanical and Optical Resonators #Noise (video) #Position (finance) #Quantum #Quantum Information and Cryptography #Quantum entanglement #Quantum limit #Quantum noise #Quantum sensor #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1126/science.abf5389
published as Science 372, 625-629 (2021)
openalex created_date 2020/10/01 · openalex publication_date 2021/05/06 · arxiv created 2021/05/12 · arxiv updated 2021/05/13 · openalex updated_date 2026/08/05
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 back-action of the measurement by constructing one effective oscillator from two physical oscillators. We realize such a quantum mechanics-free subsystem using two micromechanical oscillators, and show the measurements of two collective quadratures while evading the quantum back-action 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.