Mechanical detection of nuclear decays

Measuring tiny forces and momentum transfers can enable many tests of fundamental physics. Levitated optomechanical systems in high vacuum, which have shown outstanding force and momentum sensitivity, are sensitive to the tiny momentum transfer from a single nucleus decaying within the object. This ensures sensitivity to any particles emitted in the decay, including neutral particles. In these systems, thermal noise can be eliminated and the fundamental sensitivity possible is set by constraints from quantum mechanics on the measurement process itself. By controlling the mechanical motion of a micron-sized particle precisely, and measuring its motion using light, we can detect individual alpha decays within the particle. Further development of this technique will enable new searches for sterile neutrinos, a type of dark matter candidate. Scaling up the sensors to large arrays will also allow searches for dark matter candidates that would evade existing detection techniques.