Non-Newtonian Gravity and Neutrality of Matter Searches with Levitated Test Masses

The universal law of gravitation has undergone stringent tests for many decades over a significant range of length scales, from atomic to planetary. Of particular interest is the short distance regime, where modifications to Newtonian gravity may arise from axion-like particles or extra dimensions. We have constructed an ultra-sensitive force sensor based on optically-levitated microspheres with a force sensitivity of 10^(−16)N/√Hz to investigate non-Newtonian forces that couple to mass with a characteristic scale of ∼ 10μm. In this talk, I will present the first investigation of the inverse-square law using an optically levitated test mass, along with the technical development that preceded it.

In addition, I will present another precision measurement conducted with the same setup aiming to determine if the charge of the proton is equal in magnitude to the charge of the neutron. This equality has been tested with great precision over the last century and has supporting arguments from the theory side. However, this measurement is a sensitive tool to probe new physics as it is breaking down in a few suggested extensions of the standard model.

Nadav is a candidate for the department; anyone interested in meeting in person for discussions, may fill in the schedule here: https://docs.google.com/spreadsheets/d/1o-xN-B27a_htzTMo-dwdfMmX4mzWfGg…