Abstract

I describe the early developments from the formulation of the theory of the relativistic string to the construction of the first consistent superstring theory, which I witnessed from a very short distance.

The relativistic string

The story begins in October 1972, when in a CERN preprint Goddard, Goldstone, Rebbi and Thorn (GGRT) formulated a complete theory of the quantized free relativistic string [GGRT73] describing the physical states of the Dual Resonance Model.

At that time this model of strong interactions, arisen from the Veneziano amplitude proposed in 1968,was already completely developed. Fubini andVeneziano [FGV69, FV69, FV70] and Bardakci and Mandelstam [BM69] had shown that the single-particle states of the Dual Resonance Model (DRM) could be described consistently by an infinite collection of harmonic oscillators. Nambu, Nielsen and Susskind had formulated independently the conjecture that the underlying microscopic structure of these physical states was a vibrating string. Nambu was apparently the first one to use this term in such a context, writing: ‘This equation suggests that the internal energy of a meson is analogous to that of a quantized string of finite length’ [Nam70a]. Susskind used a funny paraphrase: ‘a continuum limit of a chain of springs’ [Sus69], and in a note added in proof, where the works on the factorization of the N-point amplitude by Fubini and Veneziano and by Bardakci and Mandelstam were explicitly mentioned, he used the term ‘rubber band’.