A CLASSICAL UNIFIED FIELD THEORY OF GRAVITATION, ELECTROMAGNETISM AND SPIN——FOUNDATIONS

In this paper, a classical unified field theory (UFT) of gravitation and electromagnetism based on Einstein’s principle of strong geometrization of physics is proposed. The present UFT has for its mathematical foundation the reduced bundle P[M, SU(2)] with the real representation of the complex unitary group SU(2) as the structure group. The SU(2) bundle provides the kinematic background and the generalized Einstein equation on M decides the dynamic content of the universe; these twin pillars are found to determine the space-time structure completely, provided that tho affine connection is defined on the given principal fibre bundle. The space-time structure so determined then automatically implies the existence within itself of electromagnetism and intrinsic spin. In the combined interaction of gravitation and electromagnetism in which spin is the active agent, we discover the existence of something llke the "magnetic charge and current".