DTQEM: Dual-Threshold Quantum Decoherence Models – Complete Framework (v16, v17, v18, v63, Unified, ESD)

DTQEM provides a family of calibrated, first‑principles‑derived models for quantum decoherence in path‑interference and massive‑particle interferometry. The **v18.0‑C** model introduces a joint‑bath crossover term C = C₀ · exp(-a·I_path - b·ΔT/T_ref - c·I_path·ΔT/T_ref) with calibrated values (C₀=0.3675, a=1.6968, b=0.8055, c=0.5000, T_ref=300K). Performance: R²=0.9982, LOOCV R²=0.9814, RMSE=0.0045. The **v63.x** models calculate decoherence time τ_c from particle properties: τ_c = τ_c0 / [ (m/m_u)^β·(v/c)^δ·(1+ζN) ] with derived exponents β=0.44 (Debye‑Pikovski), δ=1/3 (van der Waals), ζ=0.005 (symmetry suppression). The **Unified DTQEM** model combines both frameworks into a single equation linking particle structure (m, v, N) with environmental conditions (I, T). The **ESD v1.0** extension predicts entanglement sudden death time: t_ESD = K / (α·I + β·ΔT/T_ref + γ·I·ΔT/T_ref) Key statistical result: AICc threshold N ≥ 36 required to detect joint‑bath coupling.