Towards the observation of radiation torque shot noise

The electromagnetic field is quantized. This quantization gives rise to fluctuations in the interaction with matter, a prominent example being the photon recoil noise, often termed radiation pressure shot noise. A kinematic noise associated with the quantization of the light field that has remained unobserved to date is radiation torque shot noise. This torque noise arises from the quantization of photon spin and its observation requires an optomechanical system with a rotational degree of freedom. In this contribution, we show our progress torwards the observation of radiation torque shot noise using an optically levitated nanoparticle.