Supersymmetric strings
Clifford V. Johnson · Cambridge University Press eBooks · 2023
Supersymmetric stringsThe discussion of bosonic strings in the previous five chapters allowed us to uncover a great deal of the structure essential to understanding Dbranes and other background solutions, in addition to the basic concepts used in discussing and working with critical string theory.At the back of our mind was always the expectation that we would move on to include supersymmetry.Two of the main reasons are that we can remove the tachyon from the spectrum and that we will be able to use supersymmetry to endow many of our results with extra potency, since stability and non-renormalisation arguments will allow us to extrapolate beyond perturbation theory.Let us set aside D-branes and T-duality for a while and use the ideas we discussed earlier to construct the supersymmetric string theories which we need to carry the discussion further.There are five such theories.Three of these are the 'superstrings', while two are the 'heterotic strings '*. The three basic superstring theories Open superstrings: type ILet us go back to the beginning, almost.We can generalise the bosonic string action we had earlier to include fermions.In conformal gauge it is:where the open string world-sheet is the strip 0 < (J < 'IT, -00 < T < 00.* A looser and probably more sensible nomenclature is to call them all 'superstrings', but we'll choose the catch-all term to be the one we used for the title of this chapter.