Relaxation-Driven Cyclic Cosmology (RDCC) v17.0 - Minimal Effective Two-Sector Version

Relaxation-Driven Cyclic Cosmology (RDCC) v17. 0, is a minimal, nonsingular, eternally cyclic cosmological model formulated entirely within Einstein gravity and a single complex scalar field Φ in a radiatively tilted double-well potential. By introducing a gravitationally coupled CPT-conjugate mirror sector with reversed thermodynamic arrow of time, the framework simultaneously explains cold dark matter (ΩDM/Ωb ≈ 5. 4), the observed baryon asymmetry (ηB ≈ 6 × 10^-10), dynamic dark energy with wDE > −1, and resolves the Tolman entropy problem without global entropy growth. The cosmological bounce emerges naturally from the scalar dynamics through a transient null-energy-condition violation. CPT-symmetric matching conditions across the bounce, together with the full linear perturbation transfer matrix, recover a near-scale-invariant primordial spectrum (nₛ ≈ 0. 964, Aₛ ≈ 2. 1 × 10^-9) in excellent agreement with Planck 2018 (within 1σ). Weak gravitational cross-sector relaxation guarantees multi-cycle attractor stability over arbitrarily many cycles. The model makes concrete, tightly correlated and highly testable predictions, including a stochastic gravitational-wave background peaked at 10^-3–10^-2 Hz (with a hidden mirror component), 21-cm modulations at the 0. 2–0. 3 % level, ΔNₑff ∼ 0. 1–0. 3, and percent-level corrections to f_σ8 (z). RDCC thus constitutes a clean, purely effective-field-theoretic and observationally falsifiable alternative to ΛCDM that requires no inflation, no modified gravity, and no additional fundamental fields. 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 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