Eisenbud-Wigner-Smith model

The Eisenbud-Wigner-Smith model describes how particles, like electrons or photons, interact with a target—such as an atom or molecule—by examining the scattering process. It focuses on the concept of "phase shifts," which are changes in the particle's wave as it encounters the target. By analyzing these phase shifts, the model calculates the "time delay"—how long particles spend near the interaction region compared to free movement. This approach helps scientists understand the dynamics of scattering processes, revealing details about the structure and properties of the target based on how it influences the incoming particles.