Relaxation-Driven Cyclic Cosmology (RDCC) v26.0 - Minimal Extension of ΛCDM / Bounce EFT Framework

RDCC v26. 0 – What’s New RDCC v26. 0 introduces the most substantial conceptual and structural refinement of the Relaxation‑Driven Cyclic Cosmology framework to date. This version modernizes the theoretical foundation, clarifies the origin of the primordial tilt, and strengthens the model’s predictive power while preserving strict minimality. Key new features in RDCC v26. 0: 1. Entropic mechanism for the primordial tilt (new Section 7. 11) A new, minimal, and structurally motivated mechanism for generating the observed red‑tilted primordial spectrum is introduced. Instead of relying exclusively on a steep ekpyrotic potential, the tilt now arises from isocurvature–adiabatic conversion driven by the inter‑sector relaxation parameter α ~ 10⁻². This makes the tilt a structural prediction of RDCC. 2. Ekpyrotic term becomes optionalThe exponential ekpyrotic term in the scalar potential is now treated as one possible radiative contribution rather than a required ingredient. RDCC no longer belongs to the class of classical ekpyrotic models and stands on its own conceptual foundation. 3. Fully rewritten Section 3 (Theoretical Framework) Section 3 has been completely restructured to emphasize minimality, clarify the EFT origin of all operators, integrate the entropic mechanism, and strengthen the Higgs‑EFT interpretation of the scalar field. 4. Fully rewritten Section 7 (Cosmological Perturbations) The perturbation analysis has been reorganized and expanded. It now includes explicit evolution equations for inter‑sector relaxation, bounce matching conditions, entropic conversion as the primary source of the tilt, and updated predictions for non‑Gaussianity and tensor suppression. 5. New Figure 2: Isocurvature → Adiabatic ConversionA new schematic figure illustrates the entropic mechanism, showing the damping of isocurvature modes, the growth of curvature perturbations, and the enhanced conversion near the bounce. 6. New consolidated prediction sectionRDCC v26. 0 now includes a dedicated prediction section summarizing: – ΔNₑff ~ 0. 1–0. 3– percent‑level deviations in fσ₈ (z) – 21‑cm oscillatory features at the 0. 2–0. 3% level– a LISA‑band stochastic gravitational‑wave background– cross‑epoch correlations controlled by the single parameter α 7. Improved consistency, clarity, and minimality throughoutTerminology has been unified, the role of α has been sharpened, the CPT‑symmetric two‑sector structure is emphasized, and the model is now clearly distinct from ekpyrotic cosmology. RDCC v26. 0 is the most coherent and polished version of the framework so far. 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