|
|
General Relativity in Higher Dimensions
Málek, Tomáš ; Pravda, Vojtěch (advisor) ; Raeymaekers, Joris (referee) ; Podolský, Jiří (referee)
vii Title: General relativity in higher dimensions Author: Tomáš Málek Institute: Institute of Theoretical Physics Supervisor: Mgr. Vojtěch Pravda, PhD., Institute of Mathematics of the Academy of Sciences of the Czech Republic Abstract: In the first part of this thesis, Kerr-Schild metrics and extended Kerr- Schild metrics are analyzed in the context of higher dimensional general relativ- ity. Employing the higher dimensional generalizations of the Newman-Penrose formalism and the algebraic classification of spacetimes based on the existence and multiplicity of Weyl aligned null directions, we establish various geometri- cal properties of the Kerr-Schild congruences, determine compatible Weyl types and in the expanding case discuss the presence of curvature singularities. We also present known exact solutions admitting these Kerr-Schild forms and con- struct some new ones using the Brinkmann warp product. In the second part, the influence of quantum corrections consisting of quadratic curvature invariants on the Einstein-Hilbert action is considered and exact vacuum solutions of these quadratic gravities are studied in arbitrary dimension. We investigate classes of Einstein spacetimes and spacetimes with a null radiation term in the Ricci tensor satisfying the vacuum field equations of quadratic gravity...
|
|
|
Exact spacetimes in modified theories of gravity
Karamazov, Michal ; Švarc, Robert (advisor)
In the review part of the thesis we summarize various modified theories of gravity, especially those that are characterized by additional curvature invariants in the Lagrangian density. Further, we review non-twisting geometries, especially their Kundt subclass. Finally, from the principle of least action we derive field equations for the case with the Lagrangian density corresponding to an arbitrary function of the curvature invariants. In the original part of the thesis we explicitly express particular components of the field equations for non-gyratonic Kundt geometry in generic quadratic gravity in arbitrary dimension. Then we discuss how this, in general fourth order, field equations restrict the Kundt metric in selected geome- trically privileged situations. We also analyse the special case of Gauss-Bonnet theory. 1
|
|
|
Exact spacetimes in modified theories of gravity
Karamazov, Michal ; Švarc, Robert (advisor) ; Podolský, Jiří (referee)
In the review part of the thesis we summarize various modified theories of gravity, especially those that are characterized by additional curvature invariants in the Lagrangian density. Further, we review non-twisting geometries, especially their Kundt subclass. Finally, from the principle of least action we derive field equations for the case with the Lagrangian density corresponding to an arbitrary function of the curvature invariants. In the original part of the thesis we explicitly express particular components of the field equations for non-gyratonic Kundt geometry in generic quadratic gravity in arbitrary dimension. Then we discuss how this, in general fourth order, field equations restrict the Kundt metric in selected geome- trically privileged situations. We also analyse the special case of Gauss-Bonnet theory. 1
|
|
|
General Relativity in Higher Dimensions
Málek, Tomáš ; Pravda, Vojtěch (advisor) ; Raeymaekers, Joris (referee) ; Podolský, Jiří (referee)
vii Title: General relativity in higher dimensions Author: Tomáš Málek Institute: Institute of Theoretical Physics Supervisor: Mgr. Vojtěch Pravda, PhD., Institute of Mathematics of the Academy of Sciences of the Czech Republic Abstract: In the first part of this thesis, Kerr-Schild metrics and extended Kerr- Schild metrics are analyzed in the context of higher dimensional general relativ- ity. Employing the higher dimensional generalizations of the Newman-Penrose formalism and the algebraic classification of spacetimes based on the existence and multiplicity of Weyl aligned null directions, we establish various geometri- cal properties of the Kerr-Schild congruences, determine compatible Weyl types and in the expanding case discuss the presence of curvature singularities. We also present known exact solutions admitting these Kerr-Schild forms and con- struct some new ones using the Brinkmann warp product. In the second part, the influence of quantum corrections consisting of quadratic curvature invariants on the Einstein-Hilbert action is considered and exact vacuum solutions of these quadratic gravities are studied in arbitrary dimension. We investigate classes of Einstein spacetimes and spacetimes with a null radiation term in the Ricci tensor satisfying the vacuum field equations of quadratic gravity...
|
guest ::
