Unified Field Theory and Principle of Representation Invariance

This is part of a research program to establish a unified field model for interactions in nature. The aim of this article is to postulate a new principle of representation invariance (PRI), to provide a needed mathematical foundation for PRI, and to use PRI to refine the unified field equations of four interactions. Intuitively, PRI amounts to saying that all SU(N) gauge theories should be invariant under transformations of different representations of SU(N). With PRI, we are able to substantially reduce the number of to-bedetermined parameters in the unified model to two SU(2) and SU(3) constant vectors {αμ} and {αk}, containing 11 parameters, which represent the portions distributed to the gauge potentials by the weak and strong charges. Furthermore, both PRI and PID can be directly applied to individual interactions, leading to a unified theory for dark matter and dark energy, and theories on strong and weak interaction potentials. As a direct application of the strong interaction potential, both asymptotic freedom and quark confinement are explained.