Anomalous contribution to galactic rotation curves due to stochastic spacetime

submitted by ZephirAWT from arxiv.org

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Anomalous contribution to galactic rotation curves due to stochastic spacetime

Consistency of the theory necessarily requires that the metric evolve stochastically. Here, we show that this stochastic behaviour leads to a modification of general relativity at low accelerations. In the low acceleration regime, the variance in the acceleration produced by the gravitational field is high in comparison to that produced by the Newtonian potential, and acts as an entropic force, causing a deviation from Einstein's theory of general relativity. We show that in this "diffusion regime", the entropic force acts from a gravitational point of view, as if it were a contribution to the matter distribution.

An entropic force driven by a stochastic cosmological constant can explain galactic rotation curves without needing to evoke dark matter. We caution that a greater understanding of this effect is needed before conclusions can be drawn, most likely through numerical simulations, and provide a template for computing the deviation from general relativity which serves as an experimental signature of the Brownian motion of spacetime.

Renormalisation of postquantum-classical gravity The same authors show that our theory of gravity is valid down to the shortest distances and that it can explain the expansion of the universe and galactic rotation without dark matter or dark energy.

Actually there is an macroscopic water surface analogy for this effect utilized already by nature. Brownian motion of water keeps small objects in persistent motion, which doesn't suffer with energy dissipation loses for sufficiently small accelerations. The article essentially derives Milgrom formula from MOND theory of dark matter from path integral of its action metrics g over geometries, no further evidence is given yet.

Weird wave behavior may explain why the whirligig walks in circles. Capillary-gravity waves move across the water at a minimum velocity of 23 cm/s, below which point they just can’t overcome the gravity and surface tension of the liquid. So it was generally thought that all objects must move at this minimum velocity or greater in order to create the waves. However, the recent study shows that small objects moving below 23 cm/s can still generate waves, as long as the objects are moving in circles.

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Sabine Hossenfelder: What Physicists Have Been Missing An exciting new theory reconciles gravity and quantum physics. I think it’s wrong. But I may be too.

In Oppenheim’s framework... the random changes of spacetime affect the motion of quantum particles, and those quantum particles in return affect the changes of spacetime. It is a two-way process neatly consistent with John Wheeler’s one-line summary of general relativity that “Spacetime tells matter how to move; matter tells spacetime how to curve.”

The idea of stochastic space-time isn't very new and there is an entropic gravity branch, which deals with this model for quite some time. And it's consistent with dense aether model, in which universe is intrinsically random and which handles space-time as a surface of very dense (super)fluid (think of interior of dense star similar to supercritical foam). But is it mathematically consistent with relativity and quantum mechanics? Apparently not, because both theories handle space-time as a smooth and asymptotically flat continuum. Even in quantum gravity, in which the spacetime metric is treated as classical, even while matter fields remain quantum.

Therefore the rigorous proof of mathematical consistency of stochastic space-time with existing theories won't be easy. The problem is in different observation perspectives in which these low-dimensional theories handle hyperdimensional space-time. Quantum theory looks at it from extrinsic perspective, general relativity from strictly intrinsic one. At best it can be shown that all these theories converge to same asymptotically smooth solution for low-energy density fields.

Also keep on mind, that - similarly to MOND/MOD, TeVeS/STVG, MiHSc/QI and who knows else theories - the dark matter contributions tend to be spherically symmetrical, so that they can not really account to low-dimensional artifacts of (cold) dark matter, like the extragalactic filaments and barred galaxies. The bigger picture of geometric model of LeSage gravity is still missing in microscopic description of gravity fields.