Hybrid quantum systems with ultracoherent mechanical resonators
ORAL · Invited
Abstract
Phonons hosted by soft-clamped mechanical resonators can be strongly isolated from the environment, enabling coherence times in excess of 100 ms. Tailored coupling to other quantum systems then allows manipulating the phonons’ quantum state. For example, a high-finesse optical cavity allows monitoring mechanical motion with a sensitivity at, and even beyond, the standard quantum limit. Real-time feedback then enables preparation of high-purity quantum states of motion. Similarly, a superconducing circuit coupled to the mechanical mode enables coherent control. Specifically, resolved-sideband cooling with a microwave drive prepares the mechanical quantum ground state. The next frontier are hybrid systems incorporating quantum nonlinearities. Towards this goal, we are functionalizing ultracoherent mechanical resonators with nanomagnets. Through their magnetic field gradient, they can induce longitudinal coupling to single electron spin systems—such as those hosted in the nitrogen vacancy defect in diamond—and flux-tunable transmon qubits. Ultimately, such systems can allow preparing non-Gaussian motional states, of interest for quantum sensing, including the search for gravitational decoherence effects.
–
Publication:1. Tsaturyan, Y., Barg, A., Polzik, E. S. & Schliesser, A. Ultracoherent nanomechanical resonators via soft clamping and dissipation dilution. Nat. Nanotechnol. 12, 776–783 (2017). 2. Rossi, M., Mason, D., Chen, J., Tsaturyan, Y. & Schliesser, A. Measurement-based quantum control of mechanical motion. Nature 563, 53–58 (2018). 3. Rossi, M., Mason, D., Chen, J. & Schliesser, A. Observing and Verifying the Quantum Trajectory of a Mechanical Resonator. Phys. Rev. Lett. 123, 163601 (2019). 4. Mason, D., Chen, J., Rossi, M., Tsaturyan, Y. & Schliesser, A. Continuous force and displacement measurement below the standard quantum limit. Nat. Phys. 15, 745 (2019). 5. Seis, Y. et al. Ground state cooling of an ultracoherent electromechanical system. Nat. Commun. 13, 1507 (2022). 6. Hahne, F. et al. Measuring high field gradients of cobalt nanomagnets in a spin-mechanical setup. Preprint at https://doi.org/10.48550/arXiv.2508.19156 (2025).
