LISA:
Observe gravitational wave echoes or lensing delays from geodesic scattering at vacuum layer boundaries.
Strong Lensing Surveys:
Use lensing asymmetries to map topological irregularities and fractal caustics in cosmic voids.
Positioning the Model
This model does not seek to replace CDM wholesale, but instead acts as a post-CDM extension that retains concordance on small scales while modifying structure and evolution at large/early scales. It provides a self-consistent, falsifiable, and computationally tractable framework aligned with both general relativity and current quantum gravity constraints.
The road forward lies in further numerical simulations, analytic stability analyses, and collaborations with large-survey teams to identify and constrain the parameter space of such layered, holographically inspired cosmologies.
B. Future Prospects:
This framework opens novel pathways for the next generation of cosmological experiments. By postulating that the universe consists of layered topological patches with phase-entangled boundaries, and that its large-scale structure emerges from fractal quantum tunneling dynamics, we arrive at distinctive predictions that are testable through several frontier observables. Below, we outline key future observational directions to probe this model:
1. 21cm Tomography
Relevance:
 The 21cm hydrogen hyperfine line is a sensitive probe of matter distribution and thermal history during the Cosmic Dawn and Dark Ages ( z630z \sim 6 - 30).
Predictions:
Layered vacua and variable expansion rates imply anisotropic and non-monotonic 21cm brightness temperature maps.
Enhanced small-scale clustering due to fractal density modes may produce early reionization signatures inconsistent with standard CDM timelines.
Phase-correlated heating and ionization across layers may result in non-Gaussian features in the power spectrum and bispectrum of 21cm fluctuations.
Instruments:
