Relaxation-Driven Cyclic Cosmology (RDCC): A Unified CPT-Symmetric Framework with Explicit Bounce Transfer

Relaxation-Driven Cyclic Cosmology (RDCC): A Unified CPT-Symmetric Framework with Explicit Bounce Transfer This preprint introduces Relaxation-Driven Cyclic Cosmology (RDCC), a minimalist, eternally cyclic cosmological model based on standard Einstein gravity and a single complex scalar field Φ in a radiatively tilted double-well potential. The framework is globally CPT-symmetric and timeless. Time, entropy and causality emerge only as sectoral projections of a unified underlying spacetime. RDCC unifies several fundamental phenomena without inflation, modified gravity or additional degrees of freedom: • Dark energy — realized as dynamic vacuum relaxation with equation-of-state parameter w > -1• Dark matter — as CPT-conjugate mirror-sector baryons with ΩDM / Ωb ≈ 5. 4• Baryon asymmetry — via phase-induced chemical potential balanced across sectors• Nonsingular bounce dynamics — as a structural CPT fixpoint attractor• The cosmological arrow of time — as a sectoral projection artifact The paper consolidates: • Formal axiomatic foundation (global CPT symmetry, non-separable structure, minimality) • Explicit background dynamics and nonsingular bounce solution• Full linear perturbation theory through the bounce, including - Mukhanov–Sasaki scalar modes - CPT-symmetric matching conditions - Bounce transfer function T (k) = 1 − α exp− (k/kb) ² - Tensor mode enhancement - Multi-cycle perturbative stability (|T (k) | ≤ 1) • Cross-sector relaxation mechanism preventing global entropy divergence• Emergent phenomena and Higgs fusion interpretation• Sharply testable multi-messenger predictions Key observational signatures include: • ~12% enhanced low-ℓ ISW contribution in the CMB (testable with Euclid, CMB-S4) • Peaked stochastic gravitational-wave background at 10⁻³ – 10⁻² Hz (LISA O4, Einstein Telescope) • ~0. 28% oscillatory modulation in 21-cm cosmology at k ≈ 0. 1 Mpc⁻¹ (SKA Phase 2) • Mild suppression of the S₈ parameter in large-scale structure• Potential alleviation of the Hubble tension through evolving dark energy RDCC is designed to be falsifiable in the 2035–2045 observational window. It can be ruled out if: • no GW peak is detected by LISA• ISW anomalies fully converge to standard ΛCDM expectations• primordial perturbations exhibit strong non-CPT-symmetric features• no GW leakage or ΔNₑff signatures appear As an effective field theory valid below the cutoff scale, RDCC does not claim a complete quantum-gravitational description. Future extensions may include quantum-geometric completion and detailed numerical simulations of structure formation. This work is intended for researchers in theoretical cosmology, particle astrophysics and multi-messenger astronomy. It offers a coherent structural alternative to the standard ΛCDM model while addressing several of its persistent tensions and conceptual challenges. Related documents and the full RDCC ecosystem are available via Zenodo: https: //zenodo. org/records/18204087 Michael Lehmann Independent Researcher mi. lehmann@gmx. de