Minimal Eternal Universe Theory (mEUT) A unified scalar framework for early stiff-phase dynamics and fuzzy dark matter

The Minimal Eternal Universe Theory (mEUT) provides a streamlined, unified scalar framework that addresses the core tensions of modern cosmology (ΛCDM), including the Hubble tension and the small-scale structure puzzle.

Unlike traditional models that require separate fields for inflation and dark matter, mEUT utilizes a single real scalar field to drive two distinct epochs:

1. Early Universe: A kinetic-dominated stiff-matter phase (w=+1) that naturally resolves the horizon and flatness problems through a non-singular quantum bounce, eliminating the initial singularity.

2. Late Universe: A transition into a coherent oscillatory regime where the field acts as ultralight fuzzy dark matter (ma∼10−22 eV), predicting kpc-scale solitonic cores in dwarf galaxies that differentiate it from standard Cold Dark Matter (CDM).

This white paper presents the analytical foundations, numerical stability parameters, and clear observational signatures (such as a blue-tilted primordial spectrum and suppressed tensor modes) required for near-term falsifiability via surveys like Euclid and LSST.

Key Features:

• Parameter Economy: A single field unifies early- and late-time dynamics.

• Non-Singular History: Cyclic evolution avoids the "beginning of time" problem.

• Observational Accuracy: Resolves the core-cusp problem without complex baryonic feedback.