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arXiv · 2405.08543

Distinguishing bounce and inflation via quantum signatures from cosmic microwave background

S. Mahesh Chandran·S. Shankaranarayanan
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Abstract

Cosmological inflation is a popular paradigm for understanding Cosmic Microwave Background Radiation (CMBR); however, it faces many conceptual challenges. An alternative mechanism to inflation for generating an almost scale-invariant spectrum of perturbations is a \emph{bouncing cosmology} with an initial matter-dominated contraction phase, during which the modes corresponding to currently observed scales exited the Hubble radius. Bouncing cosmology avoids the initial singularity but has fine-tuning problems. Taking an \emph{agnostic view} of the two early-universe paradigms, we propose a quantum measure -- Dynamical Fidelity Susceptibility (DFS) of CMBR -- that distinguishes the two scenarios. Taking two simple models with the same power-spectrum, we explicitly show that DFS behaves differently for the two scenarios. We discuss the possibility of using DFS as a distinguisher in the upcoming space missions.

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S. Mahesh Chandran, S. Shankaranarayanan. 2024-05-14. Distinguishing bounce and inflation via quantum signatures from cosmic microwave background. https://arxiv.org/abs/2405.08543

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