The Geometric Quantum Space: Implications for the Double-Slit and the Delayed-Choice Quantum Eraser Experiments

We study the double slit and the delayed-choice quantum eraser in the Geometric Quantum Space, in which space is an active medium: a network of truncated octahedra coupled through their square and hexagonal faces. Isotropy fixes the ratio of the two couplings and gives a dispersion relation without a linear term. A phase order of the network, the guiding state Q, takes both paths; a localized resonance M takes one and jumps between cells with rates set by the currents of Q. This process is exactly equivariant, so single hits follow the Born weight. The quantum eraser follows without any influence on the past. Every mass imprints its field on the network, so the medium records the path during separation. Unlike collapse, this record is reversible and time-independent; after recombination at most (Gm²/3ħc)(v/c)² survives, so only a second mass, not an interferometer, can read it. This gives a criterion that separates an active medium from collapse models. Preprint of an article submitted for consideration in Foundations of Physics (November 2026). A German reading version is included; the English version is authoritative.