Cosmic Information Units (CIU): A Relaxational Extension of General Relativity for Cosmological Transients

Cosmic Information Units (CIU) is proposed as a minimal extension of General Relativity in which the geometric response of spacetime to energy–momentum is not instantaneous but relaxes over a finite characteristic timescale. The framework preserves covariance, local conservation laws, and the standard Einstein field equations in the zero–relaxation limit. CIU is motivated by a class of persistent cosmological tensions, including discrepancies in the inferred expansion rate, suppressed structure growth, and lensing anomalies, which suggest limitations of instantaneous-response assumptions in non–equilibrium regimes. In CIU, spacetime curvature is sourced by a temporally relaxed, history–dependent effective energy–momentum tensor, while geodesic motion and local physics remain unchanged. Observable consequences arise exclusively in transient and non–equilibrium cosmological phases, whereas fully relaxed systems recover standard General Relativity. The framework yields clear, falsifiable predictions without introducing new matter components or modifying the fundamental geometric structure of the theory.