Year: 2026
Type: article
Abstract: The resolution of cosmological singularities remains a central challenge in the physics of the dark Universe, where dissipative effects may provide a natural alternative to exotic matter fields. We demonstrate that causal bulk-viscous fluids, governed by the Israel–Stewart theory, can generate non-singular cosmological bounces that remain stable and thermodynamically consistent. Starting from the Eckart no-go theorem, we derive analytical bounce conditions and confirm their validity through numerical integrations of parametrized scale factors. The finite relaxation time induces a controlled violation of the null energy condition while ensuring positive entropy production and finite viscous pressure at the bounce. When extended to [Formula: see text] gravity and Loop Quantum Cosmology (LQC), higher-curvature and quantum-geometry corrections further enhance the robustness of these causal bounces. The framework thereby establishes dissipative transport as a physically motivated mechanism for singularity resolution, potentially linking early-Universe dynamics to observable imprints on primordial perturbations.
Authors: L. Yıldız, D. Kaykı, E. Güdekli
Institution: Istanbul University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7123758223