Comparative Study of Cyclic Bounce Models and the PTPC Framework

Cyclic cosmologies offer an alternative to singular Big Bang models by replacing the initial singularity with a sequence of bounces. A central challenge for all such models is the entropy problem: how to prevent entropy accumulation across successive cycles. In this paper we provide a comparative study of leading cyclic scenarios, including Conformal Cyclic Cosmology (CCC), Loop Quantum Cosmology (LQC), ekpyrotic/brane-collision models, and black-hole channel proposals. Each addresses singularity resolut...