The ’anholonomic frame’ method [1–3] is applied for constructing new classes of exact solutions of vacuum Einstein equations with off–diagonal metrics in 4D and 5D gravity. We examine several black tori solutions generated by anholonomic transforms with non–trivial topology of the Schwarzshild metric, which have a static toroidal horizon. We define ansatz and parametrizations which contain warp...

We argue that 4D gravity is drastically modified at distances larger than the horizon scale, due to the large infrared quantum fluctuations of the conformal part of the metric. The infrared dynamics of the conformal factor is generated by an effective action, induced by the trace anomaly of matter in curved space, analogous to the Polyakov action in two dimensions. The resulting effective scala...

A theory of topological gravity is a homotopy-theoretic representation of the Segal-Tillmann topologification of a two-category with cobordisms as morphisms. This note describes some relatively accessible examples of such a thing, suggested by the wall-crossing formulas of Donaldson theory. 1 Gravity categories A cobordism category has manifolds as objects, and cobordisms as morphisms. Such cat...

We embed the Loop Quantum Gravity Barbero-Immirzi parameter and field within an action describing 4D, N = 1 supergravity and thus within a Low Energy Effective Action of Superstring/M-Theory. We use the fully gauge-covariant description of supergrav-ity in (curved) superspace. The gravitational constant is replaced with the vacuum expectation value of a scalar field, which in local supersymmetr...

Gravity in five-dimensional braneworld backgrounds often exhibits problematic features, including kinetic ghosts, strong coupling, and the vDVZ discontinuity. These problems are an obstacle to producing and analyzing braneworld models with interesting and potentially observable modifications of 4d gravity. We examine these problems in a general AdS5/AdS4 setup with two branes and localized curv...

We investigate the massive graviton contributions to 4D gravity in a 6D brane world scenario, whose bulk field content can include that of 6D chiral gauged supergravity. We consider a general class of solutions having 3-branes, 4D Poincaré symmetry and axisymmetry in the internal space. We show that these contributions, which we compute analytically, can be independent of the brane vacuum energ...

A bstract The cobordism conjecture implies that consistent theories of Quantum Gravity must admit the introduction boundaries. We study dynamical realization in type IIB AdS 5 × S , using existing gravity duals 4d

Table of contents Chapter 1 ‘Incremental formulation of 3D/4D variational assimilation—an overview’ Chapter 2 ‘3D variational assimilation’ Chapter 3 ‘4D variational assimilation’ Chapter 4 ‘Background term’ Chapter 5 ‘Conventional observational constraints’ Chapter 6 ‘Satellite observational constraints’ Chapter 7 ‘Background, analysis and forecast errors’ Chapter 8 ‘Gravity-wave control’ Chap...

Table of contents Chapter 1 ‘Incremental formulation of 3D/4D variational assimilation—an overview’ Chapter 2 ‘3D variational assimilation’ Chapter 3 ‘4D variational assimilation’ Chapter 4 ‘Background term’ Chapter 5 ‘Conventional observational constraints’ Chapter 6 ‘Satellite observational constraints’ Chapter 7 ‘Background, analysis and forecast errors’ Chapter 8 ‘Gravity-wave control’ Chap...