Synthesizing Nonlinearities for Quantum Sensing in Levitated Optomechanics

About This Grant

Quantum technologies promise the creation of environmental sensors which outperform classical devices. However, a quantum advantage in sensitivity is challenging in practice because of the fragility of the quantum states they employ. In this project, the research team will create a table-top sensor that exhibits quantum enhanced sensitivity without the necessity of using fragile quantum states. The platform that makes this possible uses focused laser light to hold a nanoscale sized bead, an arrangement called an optical tweezer. The optical tweezer, by using additional laser beams and electronic signal processing, can be controlled to create states of bead motion which mimic quantum states. These novel states of motion can be used as a sensing and metrology platform which surpasses the standard quantum limit, with estimated sensitivity enhancements of approximately one thousand. The research promises to uncover a new fundamental understanding in nanoscale optical physics and will also create a sensor that could impact a variety of fields across the natural sciences. Some example applications include detecting gravitational waves, searching for non-Newtonian gravity and testing quantum wavefunction collapse models. The project will also expose high school students and undergraduates to the excitement of optical physics, motivating them to consider future education and careers in STEM. In parallel, graduate students will be trained as optical scientists prepared to make an impact on future knowledge and the technology economy. Levitated nanoparticles in ultra-high vacuum optical tweezers provide a novel platform to realize and emulate tabletop quantum phenomena at room temperature. The research program will create a new frontier known as levitated optomechanics that utilizes optically mediated nonlinear dynamics to create macroscopic mechanical states of nanoparticle motion. By the controlled dynamic coupling of two transverse oscillation modes of the levitated oscillator it will be possible to engineer nonlinear dynamics. When the coherent motional coupling occurs at the sum of the two oscillator’s natural oscillation frequencies the optical tweezer dynamics mirror that of a nondegenerate parametric oscillator (NDPO). The synthesis of NDPO-like dynamics presents an opportunity to prepare two-mode squeezed states. Building on these novel levitated optomechanical states, NDPO and beamsplitter interactions will be combined to create a nonlinear phonon interferometer that possess Heisenberg-limited measurement sensitivities in the oscillator’s average phonon number. The proposed research will create new fundamental knowledge in nanoscale nonlinear quantum phononics, and have technological impact in small-size, lightweight and low-power sensors that exhibit a quantum advantage in sensitivity. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.