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Coherently coupled mechanical oscillators in the quantum regime



Panyu Hou, Jenny Wu, Stephen Erickson, Daniel Cole, Giorgio Zarantonello, Adam Brandt, Andrew C. Wilson, Daniel Slichter, Dietrich Leibfried


Coupled harmonic oscillators are ubiquitous in physics and play a prominent role in quantum science. They are a cornerstone of quantum mechanics and quantum field theory, where second quantization relies on harmonic oscillator operators to create and annihilate particles respectively. Descriptions of quantum tunneling, beamsplitters, coupled potential wells, "hopping terms", decoherence and many other phenomena rely on coupled harmonic oscillators. Despite their prominence, separate quantum harmonic oscillators have been coupled and coherently controlled in few experimental systems. Here, an oscillating electric field with suitable spatial variation parametrically couples spectrally separate pairs of modes of harmonic motion in multi-ion crystals to realize coherent exchange of single motional quanta between modes with controlled timing, strength, and phase of the coupling. We demonstrate high-fidelity quantum state transfer, entanglement of motional modes, and Hong-Ou-Mandel type interference. We also project a harmonic oscillator into its ground state and preserve that state during repetitions of the projective measurement, an important prerequisite for non-destructive state verification in continuous variable quantum error correction. Controllable coupling between separate harmonic oscillators can aid high-fidelity operations for quantum information processing with continuous variables, quantum simulation and precision measurements. It can also enable cooling and quantum logic spectroscopy involving motional modes of trapped ions that are not directly accessible.


Coupled quantum harmonic oscillators, trapped ions, quantum information processing, bosonic error correction


Hou, P. , Wu, J. , Erickson, S. , Cole, D. , Zarantonello, G. , Brandt, A. , Wilson, A. , Slichter, D. and Leibfried, D. (2022), Coherently coupled mechanical oscillators in the quantum regime, arXiv, [online], (Accessed April 23, 2024)
Created June 19, 2022, Updated March 30, 2024