We first develop the wave equation for a relativistic spin-0 particle. Starting with a spinless particle allows us to elucidate some of the new physical properties resulting from requiring relativistic covariance while at the same time delaying the development of the more involved mathematics needed to handle particles with spin.

- Wave Equation for a Spin-0 Particle
- Lorentz Invariance
- Solutions of the Klein-Gordon Equation
- General Solution of the Klein-Gordon Equation
- Conserved Current and Charge

- Orthogonality and Normalization
- Interaction with the Electromagnetic Field

- Klein-Gordon Equation in Schrödinger Form
- Zitterbewegung
- Klein Paradox for Spin-0 Particles
- Coulomb Interaction
- Homogeneous Green Function
- Completeness
- Summary
- Problems

2004-03-18