Relativistic Quantum Tunneling: A Dirac-WKB Derivation and a Parameterized Lambda Study

This educational technical note derives the leading semiclassical tunneling exponent for a one-dimensional particle in a static electrostatic potential from the local Dirac dispersion relation, and shows how the Schrödinger WKB result follows in the low-energy limit. It also introduces a hypothetical parameter lambda multiplying the quadratic relativistic term and compares the corresponding exponents for a defined rectangular barrier. The standard Dirac-WKB derivation reproduces established relativistic quantum mechanics; it is not presented as a new physical law. The lambda modification is exploratory and has no independent theoretical derivation or experimental support in this note. The numerical comparison is a sensitivity calculation for an illustrative 10 fm rectangular barrier with constant Delta = 0.1 MeV and mu*c^2 = 1118 MeV. It is not a realistic D-T interaction model or a prediction of a fusion reaction rate. The note does not claim cold fusion, anomalous fusion enhancement, or reactor-relevant performance. A one-particle Dirac equation does not describe the complete D-T nuclear collision, which involves composite nuclei, strong-interaction channels, spin, and plasma/environment effects. The cited 2026 D-D metallic-hydride study concerns ion-beam and electrochemical loading conditions and does not validate the hypothetical lambda model or establish self-sustaining fusion. AI assistance: ChatGPT assisted with literature triage, numerical calculations, equation review, and drafting. Chaman Prakash Kanth is responsible for the scientific assumptions, calculations, manuscript, and metadata.