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 (Ω_DM/Ω_b ≈ 5.4), the observed baryon asymmetry (η_B ≈ 6 × 10⁻¹⁰), dynamic dark energy with w_DE > −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 (n_s ≈ 0.964, A_s ≈ 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, ΔN_eff ∼ 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