## Geometry of Membrane Sigma Models

- String theory still remains one of the promising candidates for a unification of the theory of gravity and quantum field theory. One of its essential parts is relativistic description of moving multi-dimensional objects called membranes (or p-branes) in a curved spacetime. On the classical field theory level, they are described by an action functional extremalising the volume of a manifold swept by a propagating membrane. This and related field theories are collectively called membrane sigma models. Differential geometry is an important mathematical tool in the study of string theory. It turns out that string and membrane backgrounds can be conveniently described using objects defined on a direct sum of tangent and cotangent bundles of the spacetime manifold. Mathe- matical field studying such object is called generalized geometry. Its integral part is the theory of Leibniz algebroids, vector bundles with a Leibniz algebra bracket on its module of smooth sections. Special cases of Leibniz algebroids are better known Lie and Courant algebroids. This thesis is divided into two main parts. In the first one, we review the foundations of the theory of Leibniz algebroids, generalized geometry, extended generalized geometry, and Nambu- Poisson structures. The main aim is to provide the reader with a consistent introduction to the mathematics used in the published papers. The text is a combination both of well known results and new ones. We emphasize the notion of a generalized metric and of corresponding orthogonal transformations, which laid the groundwork of our research. The second main part consists of four attached papers using generalized geometry to treat selected topics in string and membrane theory. The articles are presented in the same form as they were published.

Publishing Institution: | IRC-Library, Information Resource Center der Jacobs University Bremen |
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Granting Institution: | Jacobs Univ. |

Author: | Jan Vysoký |

Referee: | Peter Schupp, Branislav Jurčo, Alan T Huckleberry, Olaf Lechtenfeld |

Advisor: | Peter Schupp, Branislav Jurčo |

Persistent Identifier (URN): | urn:nbn:de:gbv:579-opus-1002355 |

Document Type: | PhD Thesis |

Language: | English |

Date of Successful Oral Defense: | 2015/07/15 |

Year of Completion: | 2015 |

Date of First Publication: | 2015/09/15 |

Academic Department: | Mathematics & Logistics |

PhD Degree: | Mathematics |

Focus Area: | Mobility |

Library of Congress Classification: | Q Science / QC Physics / QC770-798 Nuclear and particle physics. Atomic energy. Radioactivity / 794.6.S85 String models [incl. superstring theories] |

Other Organisations Involved: | Czech Technical University |

Double Doctoral Agreement with: | Czech Technical University |

Call No: | Thesis 2015/30 |