Non-conventional Strings and Branes and their Interactions

Abstract

Every physical system is characterized by its action. The standard measure of integration is the square root of a minus the determinant of the metric. It is chosen on the basis of a single requirement that it must be a density under diffeomorphic transformations. Therefore, it may not be a unique choice. In this thesis, we develop the two-measure and the Galileon measure string and superstring actions, apply one of them to the string model of hadrons and present the modified measure extension to higher dimensional extended objects.