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GR20/Amaldi10 | Abstract Book Local Organising Committee July 6, 2013 Contents A1 - Exact solutions and their interpretation3 Oral session...............................................3 Poster session.............................................. 12 A2 - Mathematical relativity and other progress in classical gravity theory 17 Oral session............................................... 17 Poster session.............................................. 24 A3 - Modified gravity theories 35 Oral session............................................... 35 Poster session.............................................. 43 A4 - Complex and conformal methods in classical and quantum gravity 51 Oral session............................................... 51 Poster session.............................................. 57 B1 - Relativistic astrophysics 59 Oral session............................................... 59 Poster session.............................................. 66 Joint session B2 and B4: Approximate solutions to Einstein equations, Methods and Applications' 74 Oral session............................................... 74 B2 - Numerical relativity and astrophysical applications 78 Oral session............................................... 78 Poster session.............................................. 86 B3 - Numerical relativity : methods, theoretical gravity and high energy applications 88 Oral session............................................... 88 Poster session.............................................. 94 B4 - Analytic approximations, perturbation theory, effective field theory methods and their applications 97 Oral session............................................... 97 B5 - Observational cosmology 105 Oral session............................................... 105 Poster session.............................................. 107 B6 - Theoretical/mathematical cosmology 110 Oral session............................................... 110 Poster session.............................................. 115 C1 - Pulsar Timing Arrays: Latest Developments and Future Directions 123 Oral session............................................... 123 Poster session.............................................. 127 1 C2 - GWs: Search Results, Data Analysis and Parameter Estimation 128 Oral session............................................... 128 Poster session.............................................. 133 C3 - Progress and Challenges in Advanced Ground Based Detectors 145 Oral session............................................... 145 Poster session.............................................. 150 C4 - Concepts and Research for Future Detectors 163 Oral session............................................... 163 Poster session.............................................. 169 C5 - Space Based Detectors 178 Oral session............................................... 178 Poster session.............................................. 183 C6 - Q&A Everything you wanted to know about GWs but were afraid to ask 190 Oral session............................................... 190 C7 - Multi-Messenger Astronomy of GW Sources 192 Oral session............................................... 192 Poster session.............................................. 196 C8 - Education and Public Outreach on Gravitational Wave Astronomy 200 Oral session............................................... 200 Poster session.............................................. 203 C9 - Experimental gravitation 205 Oral session............................................... 205 Poster session.............................................. 214 Joint session D1, D2 and D4: The Quantum Mechanics of Black Hole Evaporation 216 Oral session............................................... 216 D1 - Loop quantum gravity and spin foams 218 Oral session............................................... 218 Poster session.............................................. 227 D2 - Strings, branes and M-theory 229 Oral session............................................... 229 Poster session.............................................. 235 D3 - Causal sets, causal dynamical triangulations, non-commutative geometry, and other approaches to quantum gravity 236 Oral session............................................... 236 Poster session.............................................. 242 D4 - Quantum fields in curved space-time, semiclassical gravity, quantum gravity phe- nomenology, and analog models 243 Oral session............................................... 243 Poster session.............................................. 254 2 A1 - Exact solutions and their interpretation Oral session Sagemanifolds: a free package for differential geometry and tensor calculus Gourgoulhon E, Bejger M SageManifolds is a new package for the modern computer algebra system Sage, implementing differential geometry and tensor calculus. As Sage, it is a free and open source software based on the Python pro- gramming language. This last feature makes it easy to use for anybody with a basic knowledge of Python. We shall present SageManifolds, focussing on applications to general relativity, such as computations of the Riemann and Ricci tensors in spacetimes of arbitrary dimensions, performing complicated changes of coordinates, evaluating the intrinsic and extrinsic geometry of submanifolds, performing conformal decompositions, using exterior calculus on differential forms, checking exact solutions of Einstein equa- tions and visualization of tensorial fields. Computationally-heavy tasks may be assisted using Cython, the C-extensions for the Python language, to improve the overall speed. We shall also demonstrate the pedagogical usage of SageManifolds in teaching general relativity. Analyzing and visualizing the kerr vacuum via gradient flows Abdelqader M , Lake K We explore the global structure of the Kerr spacetime using a new visualization and analysis tool based on gradient fields of scalar invariants. We discover that the observable structure (i.e. outside the horizon) of the Kerr vacuum does not vary smoothly with the spin parameter, but goes through a significant qualitative change at some specific "transitional" values of the spin parameter. The number of the gradient fields’ critical points and their index, or winding number, along the axis of symmetry changes at these transitional values of angular momentum. This result is more than a mathematical exercise, since these gradient fields represent the cumulative tidal and frame-dragging effects of the spacetime in an observer independent way. Therefore, the result has significant applications in theoretical astrophysics by possibly providing an alternative method to extract mass and angular momentum information in numerical relativity simulations, as well as shedding light on the effect of different spin parameter values on the characteristics of relativist jets produced by black holes. 3 Regularized kerr-newman solution as a model of spinning particle Burinskii A Parameters of spinning particles correspond to over-rotating Kerr geometry, for which the black-hole horizons disappear and the Kerr singular ring is naked, forming a two-sheeted Kerr-Schild background, which requires formation of a regular source. We discuss development of the regular model of the source of Kerr-Newman (KN) solution from the Keres-Israel-Hamity rotating disk model to the L'opez membrane-bubble model, and further to the gravitating soliton model, which is formed as a domain wall bubble, representing a bag filled by Higgs field in a false-vacuum state [arXiv: 1003.2928]. We describe a supersymmetric model of the corresponding phase transition. The gravitating soliton model of the KN source has important peculiarities: 1) the internal Higgs field is oscillating with frequency ! = 2m, 2) there appears the vortex-like closed superconducting string, 3) the KN vector potential forms a closed Wilson loop, which requires quantizatio Scalar multi-wormholes Sushkov S, Egorov A, Kashargin P We construct an exact axially symmetric solution describing n wormholes in general relativity with the phantom scalar field possessing the negative kinetic energy. The spacetime of multi-wormholes is everywhere regular and has no event horizons. It has a complicated topological structure. Namely, in the spacetime there exist 2n asymptotically flat regions connected by throats. Off-diagonal wormhole deformations in modified massive gravity Vacaru S There are explored off-diagonal deformations of "prime" metrics in Einstein gravity (as examples, we cosider wormhole configurations) into "target" exact solutions in f(R,T)-modified and massive/ bi-metric gravity theories. The new classes of solutions may posses, or not, Killing symmetries and can be char- acterized by effective induced masses, anisotropic polarized interactions and cosmological constants. For nonholonomic deformations with (conformal) ellipsoid/ toroid and/or solitonic symmetries and, in par- ticular, for small eccentricity rotoid configurations, we can generate wormholes like objects matching external black ellipsoid - de Sitter geometries. We conclude that the solutions with nontrivial nonholo- nomically induced torsion can not be alternatively described as effective/analogous Einstein spaces. For zero torsion configurations, there are nonholonomic tansforms and/or non-trivial limits to exact solu- tions in general relativity when modified/ massive gravity effects are modelled by off-diagonal and/or nonholonomic parametric interactions. Static spherical black holes
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