An alternative to dark matter and dark energy: Scale-dependent gravity in superfluid vacuum theory

TL;DR

This paper proposes a scale-dependent gravity model based on superfluid vacuum theory, explaining galactic rotation curves, cosmic acceleration, and the Hubble constant discrepancy without dark matter or dark energy.

Contribution

It introduces a multi-scale gravity framework derived from superfluid vacuum theory, providing explanations for cosmic acceleration and galactic dynamics without dark matter or dark energy.

Findings

Explains galactic rotation curves without dark matter.

Accounts for the universe's accelerated expansion.

Predicts gravity behavior at various cosmic scales.

Abstract

We derive an effective gravitational potential, induced by the quantum wavefunction of a physical vacuum of a self-gravitating configuration, while the vacuum itself is viewed as the superfluid described by the logarithmic quantum wave equation. We determine that gravity has a multiple-scale pattern, to such an extent that one can distinguish sub-Newtonian, Newtonian, galactic, extragalactic and cosmological terms. The last of these dominates at the largest length scale of the model, where superfluid vacuum induces an asymptotically Friedmann-Lemaitre-Robertson-Walker-type spacetime, which provides an explanation for the accelerating expansion of the Universe. The model describes different types of expansion mechanisms, which could explain the discrepancy between measurements of the Hubble constant using different methods. On a galactic scale, our model explains the non-Keplerian behaviour of galactic rotation curves, and also why their profiles can vary depending on the galaxy. It also makes a number of predictions about the behaviour of gravity at larger galactic and extragalactic scales. We demonstrate how the behaviour of rotation curves varies with distance from a gravitating center, growing from an inner galactic scale towards a metagalactic scale: a squared orbital velocity's profile crosses over from Keplerian to flat, and then to non-flat. The asymptotic non-flat regime is thus expected to be seen in the outer regions of large spiral galaxies.