Microscale torsion resonators for short-range gravity experiments

Measuring gravitational interactions on sub-100-$\mu$m length scales offers a window into physics beyond the Standard Model. However, short-range gravity experiments are limited by the ability to position sufficiently massive objects to within small separation distances. Here we propose mass-loaded silicon nitride ribbons as a platform for testing the gravitational inverse square law at separations currently inaccessible with traditional torsion balances. These microscale torsion resonators benefit from low thermal noise due to strain-induced dissipation dilution while maintaining compact size (<100$\,\mu$g) to allow close approach. Considering an experiment combining a 40$\,\mu$g torsion resonator with a source mass of comparable size (130$\,\mu$g) at separations down to 25$\,\mu$m, and including limits from thermomechanical noise and systematic uncertainty, we predict these devices can set novel constraints on Yukawa interactions within the 1-100$\,\mu$m range.