Becker, Katrin2015-04-282017-04-072015-04-282017-04-072014-122014-11-17http://hdl.handle.net/1969.1/153924Higher derivative corrections to effective actions are very important and of great interest in string theory. The aim of this dissertation is to develop a method to constrain the higher derivative corrections to O-plane actions using non-linear T-duality. In this dissertation, we first illustrate this method with the simplest case without R-R field. We classify all possible two- and four-derivative couplings, which are compatible with diffeomorphism invariance and B-field gauge invariance, of bulk NS-NS sector fields with a single Op-plane. This is applicable to type IIA or IIB superstrings or to the bosonic string. We then consider this general action in various classes of backgrounds that admit a U(1) isometry and determine the constraints on the couplings from consistency with T-duality. We show that this consistency requires the two-derivative action to vanish, and the entire non-linear four-derivative action is fixed up to one overall constant which can be determined by comparison with a two-point scattering amplitude. The resulting action is consistent with all previously computed couplings. Then we use this method over actions involving any number of NS-NS fields and just one R-R field. We first list all possible couplings up to four derivatives, then we reproduce the T-duality procedure for two-derivative case and show that the action vanishes in this case, which is also consistent with results in literature.enO-plane ActionT-dualityHigher DerivativeThesis