Relaxation-Driven Cyclic Cosmology (RDCC) v18.0 - Minimal Effective Two-Sector Version

Relaxation-Driven Cyclic Cosmology (RDCC) v18. 0 - Minimal Effective Two-Sector Version This is the updated v18. 0 release of RDCC, superseding v17. 0. Core improvement in v18. 0: We introduce a minimal, radiatively generated ekpyrotic term δ exp (−c Φ) (δ ≈ 10^-10, c ≈ 7. 5, arising naturally from mirror-sector loops) into the single complex scalar potential. This term dominates only during the long contracting phase, inducing a steep ekpyrotic regime (w ≫ 1) that automatically produces the observed red-tilted primordial spectrum ns ≈ 0. 964 directly from the dynamics — resolving the previous blue-tilt issue of slow-roll contraction while preserving the strict minimality of the framework. Key features of RDCC: - Single complex scalar field Φ + Einstein gravity only - Global CPT symmetry with CPT-conjugate mirror sector (reversed thermodynamic arrow) - Nonsingular bounce with holonomy-inspired correction - Mirror-sector baryons as cold dark matter (ΩDM/Ωb ≈ 5. 4, parameter-free) - Dynamic dark energy with wDE > −1 from radiative tilt - Tolman entropy problem solved (global entropy strictly conserved) - Baryon asymmetry from sectoral dynamics (ηB ≈ 6 × 10^-10) - Near-scale-invariant spectrum ns ≈ 0. 964 and Aₛ ≈ 2. 1 × 10^-9 in excellent agreement with Planck 2018 (within 1σ) Concrete, tightly correlated predictions- Stochastic GW background peaked at 10^-3–10^-2 Hz (LISA) - Percent-level suppression in f_σ8 (z) (Euclid/DESI detectable) - 21-cm modulations at 0. 2–0. 3 % level (SKA) - ΔNₑff ∼ 0. 1–0. 3 RDCC remains a clean, purely effective-field-theoretic, observationally falsifiable alternative to ΛCDM that unifies inflation-like perturbations, dark matter, dark energy, baryogenesis and the arrow of time from a single structural principle. Version note v18. 0 resolves the spectral-index issue of v17. 0 through a minimal, radiatively natural ekpyrotic correction. All other predictions and the overall architecture remain unchanged. Full LaTeX source and numerical codes are included in the supplementary files. This version builds on: Relaxation-Driven Cyclic Cosmology (RDCC) v1. 0: A Minimal Eternal Framework and Its Dynamical Realization: https: //zenodo. org/records/18281686 Relaxation-Driven Cyclic Cosmology (RDCC) v2. 0: A Minimal Eternal Framework with Dynamical Realization and Extensions: https: //zenodo. org/records/18304744 Relaxation-Driven Cyclic Cosmology (RDCC) v5. 0: Bounce-Matching Formalism, Mirror-Sector Dynamics, and Refined Gravitational Waves: https: //zenodo. org/records/18307836 Relaxation-Driven Cyclic Cosmology (RDCC) v6. 0: Black Hole Bounces as Local CPT-Fixpoints, Full Perturbation Transfer Matrix and Mirror-Sector Microphysics: https: //zenodo. org/records/18312656 Relaxation-Driven Cyclic Cosmology (RDCC) v7. 0: Quantum-Corrected Black Hole Bounces, Full Perturbation Transfer Matrix with Phase-Shift, and Mirror Microphysics https: //zenodo. org/records/18327084 Relaxation-Driven Cyclic Cosmology (RDCC) v8. 0: Parameter Space Exploration, Data Confrontation, and Predictive Structure Formation https: //zenodo. org/records/18334398 Relaxation-Driven Cyclic Cosmology (RDCC) v9. 0: Predictive Cosmology, Nonlinear Structure Formation, and Astrophysical Signatures https: //zenodo. org/records/18336237 Relaxation-Driven Cyclic Cosmology (RDCC) v10. 0: Unified Cosmology, Full Simulations, and Observational Pipelines https: //zenodo. org/records/18336865 Relaxation-Driven Cyclic Cosmology (RDCC) v11. 0: Entropy Dynamics, Mirror Thermodynamics, EFT Consistency, and Naturalness https: //zenodo. org/records/18341147 Relaxation-Driven Cyclic Cosmology (RDCC) v12. 0: Precision Predictions, Multi-Probe Confrontation, and Quantum-Geometric Completion https: //zenodo. org/records/18346555 Relaxation-Driven Cyclic Cosmology (RDCC) v13. 0: Quantum Completion, Global Consistency, and Predictive Cosmology https: //zenodo. org/records/18348450 Relaxation-Driven Cyclic Cosmology (RDCC) v14. 0: Unified Quantum Gravity, Full-Cycle Simulation, and Multi-Messenger Precision Cosmology https: //zenodo. org/records/18351916 Relaxation-Driven Cyclic Cosmology (RDCC) v15. 0: Mirror-Sector Cosmology, Hidden-Universe Gravitational Waves, and Two-Sector Evolution https: //zenodo. org/records/18358095 Relaxation-Driven Cyclic Cosmology (RDCC) v16. 0: Precision Two-Sector Dynamics, Mirror Thermodynamics Refinements, and Enhanced GW Forecasts https: //zenodo. org/records/18388123 Relaxation-Driven Cyclic Cosmology (RDCC) v17. 0 - Minimal Effective Two-Sector Version https: //zenodo. org/records/18761806 While the core of RDCC remains a structural, timeless framework with fixpoint character, this document explores a dynamical realization of the bounce mechanism to enable concrete, falsifiable predictions. Related documents and the full RDCC ecosystem are available via Zenodo: https: //zenodo. org/records/18204087 Michael Lehmannmi. lehmann@gmx. de