6-10 November 2026
Zhejiang Hotel
Asia/Shanghai timezone

A Non Singular Cyclic Universe from Modified Gravity

9 Nov 2026, 11:30
30m
Parallel-Cosmology Parallel-Cosmology

Speaker

Dhiraj Kuniyal (Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India)

Description

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 ${\simeq}\,89\,\mathrm{Gyr}$, 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.

Primary authors

Prof. Saurya Das (Theoretical Physics Group, Department of Physics and Astronomy \& Quantum Horizon Alberta, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta T1K 3M4, Canada ) Dhiraj Kuniyal (Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India) Prof. Sourav Sur (Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India) Dr Mitja Fridman (Department of Physics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, B\v{r}ehová 7, 115 19 Praha 1, Czech Republic )

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