Wisconsin Quantum Institute Seminar: Eugene Simon Polzik, University of Copenhagen

Studies of extreme cases within quantum mechanics have always been particularly attractive. How macroscopic can objects be and still demonstrate unique quantum features, such as entanglement? What are the real limits of measurement precision in quantum mechanics? I will review our experiments where macroscopic objects are driven deep into the quantum regime. Observation of a quantum trajectory of motion in a quantum reference frame with, in principle, unlimited accuracy will be presented. A concept of a reference frame with an effective negative mass required for such observation will be introduced. Generation of an entangled Einstein-Podolsky-Rosen state between distant mechanical and atomic oscillators and progress towards application of those ideas to gravitational wave detection will be reported. Another challenge within quantum physics of macroscopic objects is generation of Fock states corresponding to single quantum excitations of an oscillator. Progress along those lines with states of motion and of a macroscopic spin will be presented.

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