Tensionless Strings and Supersymmetric Sigma Models: Aspects of the Target Space Geometry

摘要: In this thesis, two aspects of string theory are discussed, tensionless strings and supersymmetric sigma models. The equivalent to a massless particle in is string. Even almost 30 years after it was first mentioned, still quite poorly understood. We discuss how give rise exact solutions supergravity solve closed the ten dimensional maximally plane wave background, contraction AdS(5)xS(5) where great interest due their proposed relation higher spin gauge via AdS/CFT correspondence. For model, amount supersymmetry on its worldsheet restricts geometry target space. For N=(2,2) supersymmetry, for example, space has be bi-hermitian. Recently, with generalized complex geometry, new mathematical framework developed that especially suited models Hamiltonian formulation. Bi-hermitian so-called Kaehler but involved. various amounts phase show can established by considering equivalence between Hamilton Lagrange formulation model. study models, we find objects favor geometrical interpretation beyond geometry.