Student Theses and Dissertations

Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


All of the work presented in this thesis [1-3] evolved from the initial idea that strings, if they are to make sense, ought to exist in four spacetime dimensions. At the time that it was formulated, back in mid-1985, such an idea was thought to be impossible. There were only five string theories thatwere known to be fully consistent, [4-9] and each of these had a critical dimension of 10. The bosonic (or Veneziano) string has to live in 26 spacetime dimensions, or else a breakdown of Lorentz invariance occurs. But it is not a fully consistent theory because it contains a tachyon (a particle with negative mass squared) in its spectrum [38—40] and its amplitudes have infinities.


A thesis submitted to the faculty of The Rockefeller University in partial fulfillment of the requirements for the degree of Doctor of Philosophy

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