Quantum mechanics–free subsystem with mechanical oscillators
It is shown how it is possible to measure an oscillator without quantum back-action of the measurement by constructing one effective oscillator from two physical oscillators by realizes such a quantum mechanics–free subsystem using two micromechanical oscillators, and shows the measurements of two collective quadratures while evading the quantumBack-action on both of them.
Abstract
<jats:title>Quantum entanglement goes large</jats:title> <jats:p> Quantum entanglement occurs when two separate entities become strongly linked in a way that cannot be explained by classical physics; it is a powerful resource in quantum communication protocols and advanced technologies that aim to exploit the enhanced capabilities of quantum systems. To date, entanglement has generally been limited to microscopic quantum units such as pairs or multiples of single ions, atoms, photons, and so on. Kotler <jats:italic>et al.</jats:italic> and Mercier de Lépinay <jats:italic>et al.</jats:italic> demonstrate the ability to extend quantum entanglement to massive macroscopic systems (see the Perspective by Lau and Clerk). Entanglement of two mechanical oscillators on such a large length and mass scale is expected to find widespread use in both applications and fundamental physics to probe the boundary between the classical and quantum worlds. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article issue="6542" page="622" related-article-type="in-this-issue" vol="372">622</jats:related-article> , p. <jats:related-article issue="6542" page="625" related-article-type="in-this-issue" vol="372">625</jats:related-article> ; see also p. <jats:related-article issue="6542" page="570" related-article-type="in-this-issue" vol="372">570</jats:related-article> </jats:p>