  Collapse models postulate the existence of intrinsic noise which modifies
quantum mechanics and is responsible for the emergence of macroscopic
classicality. Assessing the validity of these models is extremely challenging
because it is nontrivial to discriminate unambiguously their presence in
experiments where other hardly controllable sources of noise compete to the
overall decoherence. Here we provide a simple procedure able to probe the
hypothetical presence of the collapse noise with a levitated nanosphere in a
Fabry-Perot cavity. We show that the stationary state of the system is
particularly sensitive, under specific experimental conditions, to the
interplay between the trapping frequency, the cavity size, and the momentum
diffusion induced by the collapse models, allowing to detect them even in the
presence of standard environmental noises.
