Can massive superpositions exclude the GRW collapse rate?
In plain words
Collapse models modify quantum mechanics so that large objects lose superpositions on their own. The original proposed rate has never been ruled out.
Precise statement
Continuous spontaneous localization with rate $\lambda$ and length $r_C$. Exclude $\lambda = 1e-16\ \mathrm{s}^{-1}$ at $r_C = 1e-5\ \mathrm{cm}$ (the GRW value of Ghirardi, Rimini and Weber) by interferometric or non-interferometric (heating, noise) tests with massive objects. Answer: yes or no, with the excluded region in the $(\lambda, r_C)$ plane.
What would settle it
An interferometry or heating experiment whose excess-decoherence bound lies below lambda = 1e-16 s^-1 at r_C = 1e-5 cm.
Status in the literature
Unverified note
Non-interferometric tests (to 2021) constrain the enhanced Adler rates, and 2025 interference of sodium clusters above 170,000 amu (Pedalino et al., arXiv:2507.21211) tightened interferometric bounds; the GRW point is not reported excluded, which should be checked against the 2025 exclusion plot.
Related problems
- Special case of Does any parameter window of white-noise CSL remain viable? · Excluding the GRW point is one point of closing the CSL window