Principles of Quantum Mechanics · Problem 20.7

The Dirac Equation — R. Shankar

Physics — Quantum Mechanics · dirac-equation-hydrogen

Problem

Consider the Dirac equation for a particle in a central potential V(r)V(r). Show that the operator K=β(Σ⋅L+ℏ)K = \beta(\boldsymbol{\Sigma}\cdot\mathbf{L} + \hbar) commutes with the Dirac Hamiltonian, and hence identify a complete set of commuting observables.

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