Unitary field theories

Abstract

The spirit that motivated Galileo, Newton, Einstein and Bohr to strive to understand nature by tracing unifying principles that underlie the diversity of physical phenomena is the motivating force behind unitary field theories. In its earlier stages, in the absence of physical facts that could have given it direction, the quest for unitary field theories was stimulated primarily by geometric notions. In recent years quantum physics and elementary‐particle theory have suggested new directions, some of which may be successful. Before we discuss these recent developments, let us review some of the background. Much of Einstein's life was devoted to searching for a theory that incorporates gravity and other fields into a generalized geometrical structure derived from the general theory of relativity.