Photon Absorption and Emission via Vibrational Mismatch in Open--Closed String Dynamics: A Worldsheet-Level Mechanism for Light-Matter Coupling

We propose a novel string-theoretic mechanism for photon absorption and emission based on vibrational mismatch during open–closed string transitions. In this framework, the photon is modeled as a transient closed string formed from two High Vibrational Energy open strings—one with electron-like and one with positron-like modes. When a photon interacts with an atomic electron modeled as a Low Vibrational Energy open string, a vibrational substitution occurs. This produces a mismatched intermediate state governed by a compatibility function V(E₁, E₂), leading to a characteristic lifetime Δτ. Using vertex operator formalism, worldsheet geometry, and amplitude analysis, we describe this mechanism and its implications for photon emission and the atomic spectrum.