Testing spontaneous wave-function collapse models on classical mechanical oscillators

We show that the heating effect of spontaneous wave-function collapse models implies an experimentally significant increment $\Delta T$ of equilibrium temperature in a mechanical oscillator. The obtained form $\Delta T$ is linear in the oscillator's relaxation time $\tau$ and independent of the mass. The oscillator can be in a classical thermal state, the effect $\Delta T$ is classical for a wide range of frequencies and quality factors. We note that the test of $\Delta T$ does not necessitate quantum state monitoring but tomography. In both gravity-related (DP) and continuous spontaneous localization (CSL) models the strong-effect edge of their parameter range can be challenged in existing experiments on classical oscillators. For the CSL theory, the conjectured highest collapse rate parameter values become immediately constrained by evidences from current experiments on extreme slow-ring-down oscillators.