Abstracts

Ljubica Davidovic

Symmetries of the bosonic string

We consider the string theory of a closed and an open string and search for the transformations of the space-time fields which do not change the physical content of the theory, i.e. the symmetry transformations. In the open string theory we start with a modified action which has an additional surface term which enables the invariance of the complete action to the general coordinate transformations and the gauge transformations. The string theory is conformally invariant world sheet field theory therefore the physics is preserved if the conformal field theories corresponding to the initial and the transformed field configurations are isomorphic.