Laboratory-Scale Framework for Fixed-Energy Photon Injection into Entangled Particle Systems (EPIP)

To our knowledge, we present the first laboratoryscale framework for investigating the influence of fixed-energy photon injection on the quantum correlations of an entangled particle pair to probe decoherence pathways. The Entangled Particle Interaction-Photon (EPIP) platform integrates a highfidelity entangled-pair source with a calibrated photon delivery system capable of introducing controlled, repeatable energy perturbations to one member of the pair. Using polarizationmaintaining optics, low-loss coupling, and time-correlated singlephoton counting, EPIP enables direct measurement of correlation degradation, phase shifts, and decoherence rates under fixed-energy conditions. While the present implementation employs a single photon energy, future work aims to incorporate tunable-energy injection-allowing combined studies of energydependent effects once both systems are validated. This work addresses a gap in experimental quantum optics by explicitly probing whether local energy-momentum transfer can measurably influence nonlocal entanglement properties without violating the no-signalling theorem. We outline the theoretical basis, apparatus design, and control protocols, and present simulated results predicting threshold-dependent correlation loss. The framework is positioned for immediate deployment in preprint and peerreview contexts, with applications in quantum communication security, foundational tests of quantum mechanics, and quantum thermodynamics.