Which-Path Determination Governed by Intrinsic Quantum Transition Probability Under a Fixed Optical Configuration in an Entangled-Photon Double-Slit Experiment

We present a new theoretical framework for which-path determination in an entangled-photon double-slit experiment. In the present proposal, the availability of which-path information is governed by the intrinsic quantum transition probability (IQTP) of an artificial atom under a fixed optical configuration, without externally modifying the optical system during the measurement process. As a representative physical implementation, the idler photon interacts locally with a fixed artificial atom, whose IQTP governs the availability of which-path information. The resulting which-path information is encoded in the excitation state of the artificial atom and becomes available through a subsequent readout process. The proposed interference modification is formulated at the level of coherent pair-generation alternatives, rather than as an idler-only local operation on a completed photon-pair state.