GR as a Special Case of the Infinite-Dimensional Multiverse Model (IDM): Limit Transition and Consistency

This article shows that General Relativity (GR) does not contradict the Infinite-Dimensional Multiverse Model (IDM) but is rather its special case – an effective theory operating on our 3‑brane in the limit of low energies and weak influence of extra dimensions. An analogy is drawn with the transition from GR to Newtonian gravity and from special relativity to classical mechanics. The concept of the quantum‑gravity threshold (QGT) is introduced – the energy scale ( EQGT ≈ 1.22 × 10¹⁹ GeV) above which quantum effects of gravity become unavoidable and classical GR ceases to be valid. Modern accelerators are 10¹⁵ times weaker than the QGT, making direct experiments on quantum gravity impossible. However, the early Universe and ultra‑high‑energy cosmic rays exhibit processes near this threshold. Three conditions are formulated under which IDM dynamics reduce to Einstein’s equations: (1) neglecting extra dimension dynamics at E EQGT ; (2) weak interaction with neighbouring universes, yielding corrections of order (E/EQGT)^2 ; (3) choosing a macroscopic description level G (coarse‑graining) that ignores quantum fluctuations and individual contributions from distant universes. The article draws on contemporary research: the infinite‑dimensional limit in gravity (Emparan, Suzuki, Tanabe, 2013), brane models (Randall–Sundrum, 1999), low‑energy quantum gravity (Wallace, 2022). It concludes that IDM does not abolish GR but indicates its place in the hierarchy of physical descriptions.