Note on bouncing backgrounds

Understand

The theory of inflation is one of the fundamental and revolutionary developments of modern cosmology that became able to explain many issues of early universe in the context of the standard cosmological model (SCM).

• However, the initial singularity of the universe, where physics is indefinite, is still obscure in the combined `SCM+inflation' scenario.
• An alternative to `SCM+inflation' without the initial singularity is thus always welcome, and bouncing cosmology is an attempt of that.
• The current work is thus motivated to investigate the bouncing solutions in modified gravity theories when the background universe is described by the spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) geometry.