Quaternionic WKB Approximation
摘要
Only a few issues, such as the hydrogen atom, the harmonic oscillator, and square wells, provide an exact solution to the Schrödinger equation. Approximation methods can be used when exact solutions to the Schrödinger equation cannot be obtained. We develop a semiclassical Wentzel–Kramers–Brillouin (WKB) approximation for the quaternionic time-independent Schrödinger equation with purely imaginary quaternionic potentials. Using a generalized ansatz, the wavefunction separates into a real phase and a reduced quaternionic amplitude. The resulting equations yield a transport law that ensures the conservation of the probability current and a dispersion relation for the phase. Two formal solutions arise, but only one reduces correctly to the complex WKB limit, resolving the apparent multivaluedness of the quaternionic wavefunction. The formalism predicts corrections to semiclassical quantities at order