Abstract
The type IIA and type IIB supergravity actions in d = 10 dimensions are the low-energy eective theories of type IIA and IIB string theory. In addition, the unique eleven dimensional supergravity theory is the low-energy eective action of M-theory. Higher order corrections to the low-energy eective actions of these supergravity theories contain perturbative and non-perturbative eectsof the corresponding string theories and, as such, understanding the structure of the higher order terms provides an insight into the perturbative and non-perturbative formulations of string theory. The U-duality groups of type IIA/B string theory and M-theory compactied on a torus to d < 10 dimensions puts powerful constraints on the higher derivative terms in the eective actions of these theories. In particular, the higher derivative terms in d = 10 􀀀 n dimensions are required to possess coecient functions that transform as En+1 (Z) automorphic forms. These automorphic forms are complex mathematical objects that encode all the perturbative and non-perturbative features of type II string theory and M-theory compactied on an torus to d dimensions. We investigate the structure of the higher derivative terms and their associated automorphic forms in the eective actions of type IIA/B string theory and M-theory. Constraints on automor-
phic forms appearing in d dimensions by dimensional reduction of arbitrary higher derivative terms in the type IIA, type IIB and M-theory eective actions to d dimensions are obtained. The behaviour of higher derivative terms in the d dimensional type II eective action in specic limits of various parameters is analysed. We derive a group theoretical interpretation for each limit. A general formula is given for a class of automorphic forms in these limits.
| Date of Award | 1 Jul 2012 |
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| Original language | English |
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| Supervisor | Neil Lambert (Supervisor) & Peter West (Supervisor) |