Field Theory of Strings

An important insight into the meaning of dual string theory vertices was provided by Mandelstam [1]. Using the light-cone-gauge formalism, he showed that the vertices can be understood as the Fourier components of delta functionals that describe the spatial overlap of a final string with the two initial strings that join together. (This idea was proposed independently by [2], [3], and J. Goldstone (unpublished).) This very straightforward and physical picture was utilized to construct expressions for scattering amplitudes as functional integrals. The power of this approach was demonstrated when Mandelstam used it to calculate fermion-fermion scattering (paper #13)…