Paper XVII in the series "History-Dependent Gravity" (HDG). This work derives a fundamental decoherence mechanism from gravitational temporal nonlocality. . . We derive a fundamental decoherence mechanism arising from the temporal nonlocality of quantum gravity. The memory kernel governing non-unitary evolution is identified with the two-point correlator of metric perturbations, establishing a direct bridge between gravitational fluctuations and the emergence of classicality. In cosmological settings, this mechanism predicts enhanced decoherence during inflation, leading to a scale-dependent suppression of the primordial power spectrum P (k) P (k) (-²/k²). Using cosmological observations, we find 10^-3\, Mpc^-1, corresponding to an effective infrared memory timescale _* 10^-29. 5\, s, significantly larger than the Planck time. This provides a natural explanation for the observed large-angle power deficit in the CMB and offers testable signatures distinguishable from alternative collapse models.
Alik Gimranov (Mon,) studied this question.