The Birth of String Theory

Abstract

A personal account is given of the six to seven years (1967–1974) during which the hadronic string rose from down-to-earth phenomenology, through some amazing theoretical discoveries, to its apotheosis in terms of mathematical beauty and physical consistency, only to be doomed suddenly by the inexorable verdict of experiments. The a posteriori reasons forwhy the theorists of the time were led to the premature discovery of what has since become a candidate Theory of Everything, are also discussed.

Introduction and outline

In order to situate historically the developments I will be covering in this Chapter, let me start with a picture (see Figure 2.1) illustrating, with the help of Michelin-guide-style grading, the amazing developments that took place in our understanding of elementary particle physics from the mid-Sixties to the mid-Seventies. Having graduated from the University of Florence in 1965, I had the enormous luck to enter the field just at the beginning of that period which, a posteriori, can rightly be called the ‘golden decade’ of elementary particle physics.

The theoretical status of the four fundamental interactions was very uneven in the mid-Sixties: only the electromagnetic interaction could afford an (almost1) entirely satisfactory description (hence a 3-star status) according to quantum electrodynamics (QED), the quantum-relativistic extension of Maxwell's theory. Gravity too had a successful theoretical description, this time according to Einstein's general relativity, its 2-star rating being related to the failure of all attempts to construct a consistent quantum extension.