Physics Program Presents
Precision Measurements Using Optically Levitated Nanospheres
Friday, September 16, 2022
Hegeman 107
12:00 pm – 1:00 pm EDT/GMT-4
12:00 pm – 1:00 pm EDT/GMT-4
Andrew Poverman ’21
Using optically levitated nano-spheres, the Geraci group at Northwestern University's Center for Fundamental Physics (CFP) makes precision measurements with the scientific goal of investigating fundamental aspects of gravity and quantum foundations. To search for effects of gravity at short ranges, we employ a dual beam optical trap to confine 300nm fused silica spheres in an optical potential. The sphere is then brought within microns of a driven oscillating mass with a periodic density structure. This oscillating mass causes the motion of the trapped nano-sphere to change as a result of gravitational interaction, and the gravitational force exerted on the nano-sphere is then measured by using imaging techniques to track its motion in the optical trap. This type of system has already shown zepto-newton force sensitivity, and is currently being updated to have even higher sensitivity as well as the capability to search for Casimir-Polder forces. Additionally, I will describe an experiment which plans to investigate quantum properties of these nano-spheres by using matter-wave interferometry. To do so, we must first cool the center of motion of the bead to its motional ground state using parametric feedback cooling. Successfully observing quantum properties of these nano-spheres will potentially open the door to a regime of physics where macroscopic objects can be put into quantum superpositions, allowing for tests of quantum foundations and the quantum to classical transition. For more information, call 845-758-6822, or e-mail [email protected].
Time: 12:00 pm – 1:00 pm EDT/GMT-4
Location: Hegeman 107