9D-USTE XV: Near-Death Experience as Transient Topological Decoupling and Projection Reversion

Based on the 9-Dimensional Unified Entropy Topological Evolution (9D-USTE) framework established in prior work, this fifteenth article formally constructs a mathematical model of near-death experience (NDE) as transient topological decoupling between a 9D consciousness trajectory and a 4D physical dissipative structure. By introducing the 9D-to-4D projection operator and its norm as the coupling strength, we resolve the dimensional normalization and quantum statistical foundation of the consciousness-body interaction. We define a 9D critical manifold \ (Mc\) as the event horizon of physical death and introduce a nonlinear recovery potential to describe the elastic recoupling dynamics. The topological closure constraint and homotopy group conservation theorem are rigorously formulated, proving the necessity of consciousness returning to its original physical substrate before reaching the minimum entropy endpoint. We provide a first-principles geometric derivation for the core NDE phenomena including timelessness, panoramic life review, and transcendental calm. This work elevates the NDE interpretation within 9D-USTE from conceptual model to mathematically consistent theoretical physics, suitable for arXiv quant-ph/cond-mat and interdisciplinary biological physics journals. This is the 15th paper in the 9D-USTE (9-Dimensional Unified Entropy Topological Evolution) series, which systematically establishes a high-dimensional topological framework for consciousness, entropy evolution, and the nature of life and death. This work marks the transition of the 9D-USTE theory from static topological description to quantitative dynamical simulation, with clear falsifiable experimental predictions for neural decoherence and brain coherence during near-death states. Uploaded files include: 1. Final submission-ready PDF of the paper (9D-USTEXVNDEPaperᵥ1. 0. pdf) 2. Complete LaTeX source code (9D-USTEXVNDESourceCode. zip) 3. Topological schematic diagram (topologyₙde. pdf) Submitted to arXiv: quant-ph (Quantum Physics) and physics. bio-ph (Biological Physics) on April 4, 2026.