Dark Matter, Dark Energy, and Quantum Uncertainty from Time's Arrow

We propose that time asymmetry is a missing structural ingredient in fundamental physics. While the dynamical laws of quantum theory and general relativity are locally time-reversal invariant, the physical world exhibits irreversible record formation, quantum uncertainty, and late-time cosmic acceleration. We model time’s arrow as a global, time-asymmetric selection principle implemented as a Schwinger--Keldysh--admissible real deformation of the real-time path integral. In this framework, quantum uncertainty arises as a local consistency condition under inaccessible global selection information, while coarse-graining of the selection functional yields an infrared curvature term that fixes the gravitational normalization and admits scale-dependent dark-sector effects. The framework preserves local causality and quantum consistency, links laboratory coherence bounds to cosmology through a falsifiable consistency structure, and avoids overclaims by emphasizing testable order-of-magnitude targets rather than a unique microscopic completion.