ABSTRACT
Show that the Klein–Gordon equation for a free particle is invariant under the Lorentz transformation. The Lorentz transformation is given by () x ′ = γ ( x − β c t ) , y ′ = y , z ′ = z , c t ′ = γ ( c t − β x ) , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429092053/5e12ab0e-ba42-4caa-9bdf-6325e9117d3e/content/eqn20_1.tif"/>
