# A quasi-matter bounce equivalent to Starobinsky inflation

## TL;DR

This paper develops a bounce cosmology model that replicates the inflationary predictions of Starobinsky inflation by using Wands' duality, allowing detailed control over primordial spectrum features.

## Contribution

It introduces a novel bounce model based on Wands' duality that emulates Starobinsky inflation's key observational parameters.

## Key findings

- Successfully maps Starobinsky inflation to a quasi-matter bounce
- Achieves correct relation between spectral index and tensor-to-scalar ratio
- Demonstrates control over primordial power spectrum contributions

## Abstract

In this paper we construct a bounce model that mimics the Starobinsky inflationary model. Our construction relies on Wands' duality, which shows that the Mukhanov-Sasaki equation has a symmetry transformation by changing appropriately its time-dependent mass term. One of the advantages of this constructive method is that one can control every contribution to the primordial power spectrum and check how far we can emulate a given primordial model with a different scenario. In particular, we show that mapping the Starobinsky inflation into a quasi-matter bounce gives the correct relation between the scalar spectral index $n_s-1$ and the tensor-to-scalar ratio $r$.