# Derivation of Dirac equation using Lorentz transform

1. Dec 29, 2009

### krishna mohan

Hi..

I was studying Ryder, Chapter 2[Quantum Field Theory]....he derives the Dirac eq using Lorentz transformations..I found the approach fascinating..but there is one part I do not really understand....

Just a few lines before he writes down the Dirac equation, he identifies $$\varphi_{R}(0)$$ with $$\varphi_{L}(0)$$ using the argument that there is no handedness when the particle at rest..

Although I do know this, I am not able to see how this follows from the arguments presented till then....Can someone please clarify this point?