Based on the fundamental picture of vacuum medium and matter perturbations, a modified gravity framework centered on density-dependent restoring force is constructed, namely Memory Force Theory. Gravity is interpreted as the response of the vacuum to matter perturbations, introducing a scalar memory-force field and a density-dependent restoring coefficient following a power-law relation: μ (ρ) = μ₀ (ρ/ρ₀) ^α. Fitting the rotation curves of 15 galaxies from the SPARC database yields a universal exponent α = 0. 385 ± 0. 02, consistent with the QCD sum rule theoretical value α = 3/8 = 0. 375 within 1σ. The framework satisfies Solar System constraints via the chameleon screening mechanism and unifies galactic dynamics, strong-field gravity, cosmic evolution, and non-perturbative QCD effects. Testable predictions include black hole shadow (0. 5% shift), gravitational wave scalar polarization (Aₛ/AT ∼ 10⁻⁶), gravitational wave dispersion (Δv/c ∼ 10⁻¹⁵), dark energy equation of state (w₀ = −0. 98 ± 0. 01), and laboratory fifth force (αₑff ∼ 5 × 10⁻⁸), falsifiable within 5–20 years.
Ma et al. (2026) studied this question.