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 (Ω_DM/Ω_b ≈ 5.4, parameter-free) - Dynamic dark energy with w_DE > −1 from radiative tilt - Tolman entropy problem solved (global entropy strictly conserved) - Baryon asymmetry from sectoral dynamics (η_B ≈ 6 × 10⁻¹⁰) - Near-scale-invariant spectrum ns ≈ 0.964 and A_s ≈ 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) - ΔN_eff ∼ 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