2018/12/03 by Massimiliano Rossi, David Mason, David L. Mason +3 · 1 citation
Engineering · Physics and Astronomy · #Force Microscopy Techniques and Applications #Mechanical and Optical Resonators #Optics #Photonic and Optical Devices #Physics #Quantum #Quantum mechanics #Resonator #Trajectory #quant-ph
paper · pdf · doi:10.1103/physrevlett.123.163601
published as Phys. Rev. Lett. 123, 163601 (2019) · 20 pages, 4 figures
arxiv created 2018/12/03 · openalex publication_date 2019/10/14 · arxiv updated 2019/10/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Continuous weak measurement allows localizing open quantum systems in state space and tracing out their quantum trajectory as they evolve in time. Efficient quantum measurement schemes have previously enabled recording quantum trajectories of microwave photon and qubit states. We apply these concepts to a macroscopic mechanical resonator, and we follow the quantum trajectory of its motional state conditioned on a continuous optical measurement record. Starting with a thermal mixture, we eventually obtain coherent states of 78% purity-comparable to a displaced thermal state of occupation 0.14. We introduce a retrodictive measurement protocol to directly verify state purity along the trajectory, and we furthermore observe state collapse and decoherence. This opens the door to measurement-based creation of advanced quantum states, as well as potential tests of gravitational decoherence models.