# Entanglement in model independent cosmological scenario

## TL;DR

This paper introduces a model-independent method using Padé expansion to study entanglement creation in the universe's evolution, constrained by cosmic observations, and analyzes fermionic entanglement entropy without relying on specific cosmological models.

## Contribution

It develops a novel, model-independent approach to analyze entanglement in cosmology using Padé approximants constrained by observations, avoiding specific scale factor assumptions.

## Key findings

- Qualitative agreement with known results in literature.
- Higher-order Padé approximants do not significantly alter entanglement results.
- The approach provides a robust framework for studying entanglement in cosmology.

## Abstract

We propose a \emph{model-independent} approach to study entanglement creation due to the dynamics between two asymptotic quantum regimes in the framework of homogeneous and isotropic universe. We realize it by Pad\'e expansion to reconstruct the functional form of scale factor, rather than postulating it a priori.This amounts to fix the Pad\'e approximants constraining the free parameters in terms of current cosmic observations. Assuming fermions, we solve the Dirac equation for massive particles and we investigate entanglement entropy in terms of modes $k$ and mass $m$. We consider two rational approximations of (1,1) and (1,2) orders, which turn out to be the most suitable choices for guaranteeing cosmic bounds. Our results show qualitative agreement with those known in literature and arising from toy models, but with sensible quantitative discrepancies. Moreover, our outcomes are model independent reconstructions which show that any higher orders departing from (1,1) do not significantly modify particle-antiparticle production (hence entanglement), if cosmic bounds are taken into account.