Perturbation Methods for Black Hole Binaries
Exact models for gravitational waves from binary black holes can only be obtained by exactly solving the full Einstein field equations. However, there is an important regime in which a perturbative treatment yields a highly accurate approximation. For binary black hole systems in which one of the black holes is much less massive than the other, one may treat the mass ratio as a small perturbation parameter. Then, the Einstein equations are amenable to a perturbative expansion in powers of this parameter. Such an expansion is particularly suitable for Extreme Mass Ratio Inspirals (EMRIs), binary black hole systems where the ratio of the black hole masses is very small. In this talk I will review recent progress and future challenges to the application of perturbation methods to study black holes as sources of gravitational waves.
Self-force via worldline integration: from extreme mass ratio inspirals to cosmic strings
Of the potential sources of gravitational waves, two of the most fascinating candidates are compact-object binary systems and cosmic strings. Binary systems typically involve a pair of neutron stars or black holes inspiralling and coalescing to produce a single remnant. On the other hand, cosmic strings are a generic feature predicted by a large number of cosmological models and fundamental physics; like binary systems their existence is expected to generate large amounts of gravitational radiation. Although these two phenomena are quite distinct in their origins and physical features, both can be modelled using closely related techniques. This talk presents a novel approach to both problems which combines new numerical and analytical methods and yields geometrical insight into the contributions to self-interaction from curved geometry (back-scattering) and trapping of null geodesics.
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