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Entangled Mechanical Oscillators



John D. Jost, Jonathan Home, Jason Amini, David Hanneke, R. Ozeri, Christopher Langer, John J. Bollinger, Dietrich G. Leibfried, David J. Wineland


Quantum mechanics describes the state and evolution of isolated systems, where entangled and superposition states can be created. Its application to large systems led Schr dinger to posit his famous cat, which exists in a superposition of alive and dead states entangled with a radioactive nucleus. We don t observe such situations in nature. This may simply be due to our inability to sufficiently isolate the system of interest from the surrounding environment a technical limitation. Another possibility is some as-of-yet undiscovered mechanism that prevents the formation of large entangled states4. Such a limitation might depend on the number of elementary constituents in the system5 or the types of degrees of freedom that are entangled. Tests of the latter possibility have been made with small numbers of photons, atoms, and condensed matter degrees of freedom. One system ubiquitous to nature where entanglement has not been demonstrated is distinct mechanical oscillators. Here we demonstrate deterministic entanglement of separated mechanical oscillators, consisting of the vibrational states of two pairs of atomic ions held in separate locations. We also demonstrate entanglement of an internal state of an atomic ion with a separated mechanical oscillator. These results show quantum entanglement in a degree of freedom that pervades the classical world. Such experiments may provide pathways towards generation of entangled states of larger scale mechanical oscillators, and offer possibilities for testing non-locality with mesoscopic systems 16. In addition, the control developed in these experiments is an important ingredient to scale up quantum information processing based on trapped atomic ions.
Nature Physics


atom trapping, ion trapping, laser cooling, laser spectroscopy, quantum entanglement, quantum information


Jost, J. , Home, J. , Amini, J. , Hanneke, D. , Ozeri, R. , Langer, C. , Bollinger, J. , Leibfried, D. and Wineland, D. (2009), Entangled Mechanical Oscillators, Nature Physics, [online], (Accessed October 18, 2021)
Created June 4, 2009, Updated February 19, 2017