  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.
