Within the Granular Cosmic Vacuum (GCV) framework, the intergalactic domain P2 is not a smooth quantum‑field‑theoretic vacuum but a granular medium composed of microscopic white holes stabilized by contracted temporal strings. Dark energy emerges from the large‑scale tension of a closed cosmic temporal string in this domain. This paper presents a dedicated and systematic treatment of how high‑energy gamma rays propagate through such a granular vacuum. When a photon leaves the galactic interior domain P1 and enters P2, it ceases to be a standard quantum field theory excitation and becomes a string photon: a wave of temporal tension propagating on the network of contracted strings that bind the microscopic white holes. This transition induces an additional, small, distance‑ and energy‑dependent attenuation on top of the usual pair‑production attenuation with the extragalactic background light and the cosmic microwave background. We introduce a phenomenological description of this extra attenuation that depends on both the propagation distance and the photon energy and show how it modifies the standard ΛCDM prediction for the observed flux from distant blazars and gamma‑ray bursts. This allows us to define a residual ratio between the observed and expected fluxes and to extract testable signatures of vacuum granularity as a function of energy and redshift. We outline a concrete data‑analysis strategy based on current and future observations from Fermi‑LAT, HESS, MAGIC, VERITAS, and the Cherenkov Telescope Array. Throughout, we emphasize that the structural strings and membranes in the GCV framework are classical geometric objects in 3+1 dimensions, not superstrings or higher‑dimensional branes. Finally, we discuss how constraints from high‑energy gamma rays can be combined with precision Casimir experiments to jointly probe both the granule scale and the associated damping parameters, providing a falsifiable experimental window into the granular structure of the cosmic vacuum.
Dahli Chabane (Mon,) studied this question.