Relativistic Theory of Free Electrons

Abstract

In this chapter, the general principles which were developed in the first chapter are now applied to the spinor field which describes the system of electrons. The field equation is the equation of Dirac (Section 3-1). As a linear partial differential equation of first order the values of the field variables are determined by the values of these variables on a space-like surface (Section 3-2). The field equation is relativistically invariant (Section 3-3). The field variables themselves do not represent observables directly, but one can construct bilinear expressions of the field variables which have the transformation properties of tensors (Section 3-4). Some of these have a simple physical interpretation.