Quantum mechanical Gaussian wavepackets of single relativistic particles
The study investigates relativistic wavepackets for charged particles in uniform motion or electric fields using the Klein-Gordon equation. The research tests whether a Gaussian state can accurately describe the charge density of these wavepackets. It finds that for a good Gaussian approximation, the initial width must be about one Compton wavelength divided by the Lorentz factor ($\lambda_C/\gamma_0$), linking this to relativistic length contraction.