This paper introduces a novel cosmological model proposing that dark matter and the cosmic vacuum (dark energy) are not separate entities but two geometric phases of a single underlying membrane-string structure. In its contracted phase, this structure manifests gravitationally as dark matter halos around galaxies; in its open phase, it forms a granular cosmic vacuum across intergalactic space, with the tension of temporal strings giving rise to dark energy. The model captures this transition through a structural order parameter representing the fraction of membranes converted from the dark matter phase to the vacuum phase over cosmic time. This leads to a fundamental prediction: dark matter is not a stable particle fluid but is slowly depleted by transforming into cosmic vacuum. Two key observational tests are proposed. First, high-energy gamma rays from distant sources should experience an extra attenuation when propagating through the granular vacuum, with a characteristic redshift dependence opposite to that expected in standard particle-based dark matter models. Second, the granular structure of the vacuum would produce a tiny, measurable correction to the Casimir force at nanometer scales. If confirmed by future observations and experiments, this framework would falsify the standard ΛCDM paradigm in favor of a unified picture where dark matter and dark energy emerge as different phases of the same cosmic structure, offering a fresh perspective on fundamental cosmology.
Dahli Chabane (2026) studied this question.