Dilatant Dark Fluid: Toward a Microphysical Dark-Sector Foundation of Lorentz Invariance, Gravity, and Cosmology

This work introduces a dark universe composed entirely of cold dark matter (CDM) in two coupled components: an ultralight superfluid scalar sector and a dispersed sector of heavier bosons, interpreted respectively as the continuous and dispersed phases of a dilatant dark fluid. Dilatancy is the crucial property that distinguishes this framework from earlier superfluid-vacuum proposals. In the stiff state of the medium it supports coupled transverse phonons—identified with photons—propagating at the characteristic speed c, while the motion of material bodies through the medium induces a velocity-dependent jamming response, with the Lorentz factor reinterpreted as a jamming factor. Within this picture, relativistic kinematics, Lorentz invariance, and the null results of invariance tests emerge as material consequences of the dark-fluid response. The superfluid sector supports quantized vortices corresponding to massive particles, with circulation structure interpreted as spin. The associated Bernoulli pressure deficit is identified with the gravitational field, so that gravity is recast as a non-fundamental force of quantum-hydrodynamic origin rooted in the dark substrate.This framework yields a hydrodynamic reading of Painlevé–Gullstrand variables and of Einstein’s field equation in terms of dark-sector microphysics rather than a fundamentally spacetime-geometric ontology. It reproduces the standard weak-field relativistic phenomenology, extends to strong-field sectors, and yields a MOND-like outer-galaxy regime through isothermality of the superfluid phase. Because photons are reinterpreted as excitations of a real dark carrier, cosmology is correspondingly reformulated: redshift is modeled as coherent, achromatic energy transfer to the background, large-scale structure as a vortex-filament morphology analogous to that observed in rotating doped superfluids, the BAO-like ruler as a material mean-vortex-spacing scale, and the CMB as the equilibrium radiative temperature of the coupled (ϕ+φ) medium. The result is a unified microphysical dark-sector framework for Lorentz invariance, gravity, and cosmology, together with explicit empirical discriminants relative to geometric GR and standard expansion-based cosmology.