CLAS Cosmogenesis Part 2: Quantum Geometric Relative Entropy, Cosmic Expansion, and the Thermodynamic Origin of Dark Energy

This paper extends the Coherent Logical Actualization Structure (CLAS) cosmogenesis framework introduced in Part 1 by formalizing the physical mechanics of cosmic expansion and dynamic dark energy. We define Quantum Geometric Relative Entropy (QGRE) within a bipartite quantum open-system framework as the fundamental measure of entanglement entropy between the actualized spatial geometry and the primordial reference background of maximal coherence (C = 1). We demonstrate that cosmic expansion (ΔV > 0) is not an arbitrary property of spacetime, but the thermodynamic response required to minimize local entropy density (S local = QGRE / V). Within this framework, dark energy naturally emerges as the internal energy associated with maintaining geometric coherence during irreversible informational differentiation, fully preserving global quantum unitarity.