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Sure, but the origin of this preprint is in the stochastic-classical/uncertain-quantum "postquantum-classical" theory the Oppenheim group is working on. Their theory is premised on a weakening of the gravitational interaction at short distances (it's "asymptotically free" and thus renormalizable) compared to perturbative quantum gravity (which is non-renormalizable by power counting). However, they discovered that the gravitational interaction in their theory can be too strong. More technically, in their diffusion limit they extract a different scalar potential than from GR's weak field limit, with the former growing (statistically) stronger with increasing radius. This in practice means even with a highly similar source, their theory predicts significantly different geodesics compared to General Relativity. Rather than abandon the theory or complicate it such that it becomes compatible with fully classical GR, they solved a Schwarzschild-de Sitter (static spherical symmetry and an expansion term which "washes out" the extra-strength gravitational potential before it gets too strong) spacetime with a galactic mass (described simply and with some restrictions) and found that the geodesics are within a standard deviation or so of stable circular MONDian orbits. That result would relieve some of the immediate concern that their theory is unphysical, and drive them towards further study of its large-length-scale behaviour. (In fact their result is better than some earlier attempts to make a generally covariant MOND by adding auxiliary gravitational fields to GR (see the overview by Famaey & McGaugh 2012). Postquantum-classical gravity was on a relativistic footing from the start, although exactly how diffeomorphism invariance and manifest covariance of formulations works in postquantum-classical gravity is really interesting, see <https://arxiv.org/abs/2402.17844> if you want details) It would be interesting to see how their theory does does -- it would have to be studied numerically -- with any sort of CDM halo. Various stellar binaries are also an obvious place to look, since for sufficiently wide ones, you can't "wash out" the extra strength of the scalar potential with an expansion term. (Wide binaries are really rough on MOND too, for comparable reasons). > it doesn't (yet?) replace anything The authors know that. From just after Eqn (23) in the preprint <https://arxiv.org/abs/2402.19459>: "While this study demonstrates that galactic rotation curves can undergo modification due to stochastic fluctuations, a phenomenon attributed to dark matter, it is important to acknowledge the existence of separate, independent evidence supporting ΛCDM. In particular, in the CMB power spectrum, in gravitational lensing, in the necessity of dark matter for structure formation, and in a varied collection of other methods used to estimate the mass in galaxies" |