Entropy Balloon Hypothesis: An Information-Based Alternative to ΛCDM Expansion

This short review presents the Entropy Balloon Hypothesis, a conceptual alternative to the standard ΛCDM cosmological model. Rather than postulating the expansion of physical space, the hypothesis suggests that cosmic acceleration arises from the inflation of locally accessible state-space—an entropy-driven process.

Key insights include:

• A direct analogy between entropy gradients and pressure,
• An effective equation-of-state parameter w_S derived from entropy growth,
• Observable predictions for the CMB anisotropy (multipole \ell \approx 20–60), BH mergers, and IR background fluctuations.

The document outlines next steps to render the idea testable, offering a novel bridge between thermodynamics, information theory, and cosmology.