A Non-Singular Cyclic Universe from Modified Gravity

Abstract

The Big Bang singularity marks a fundamental breakdown of General Relativity, yet all proposed quantum gravitational remedies invoke microphysical assumptions beyond the observational reach. We show that a minimal, purely classical modification of the gravitational potential --- preserving the inverse-square law where tested, but free to depart at unmeasured scales --- is sufficient to produce a non-singular, cyclic universe. The resulting modified gravitational formulation leads to a cosmic evolution exhibiting a bounce at a finite minimum size, followed by a regime closely akin to the concordant $\Lambda$CDM model, and an eventual collapse to another bounce. Cosmic Chronometer, Supernovae type Ia, Baryon Acoustic Oscillation, Cosmic Microwave Background and Nucleosynthesis data constrain both the new length scales, implying a cycle period of $\simeq 89$Gyr, and this framework --- subsuming a broad class of bounce scenarios within a single testable model --- opens a direct route for distinguishing cyclic cosmologies from $\Lambda$CDM.

11 pages, 2 tables and 4 figures