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Speaker |
Balmelli, Simone |
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Coauthors |
Damour, Thibault; Jetzer, Philippe |
| Talk Title |
The description of next-to-leading order spin-spin effects in an Effective-One-Body Hamiltonian |
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Abstract |
The effective-one-body (EOB) approach is among the most useful methods for describing the coalescence of black hole binaries. Providing a satisfying description of spin effects in this framework is a crucial task, which has not yet been completely achieved. I will discuss the problem of including the next-to-leading order (NLO) spin-spin coupling into the EOB. The first part of the talk will be devoted to an approach which consists in defining, as far as possible, an “effective spin squared” that must replace all appearances of the spin squared inside of the EOB Hamiltonian. The result is, however, an Hamiltonian where the spins are coupled to terms that are quartic in the momenta, thus significantly deviating from the structure of a metric Hamiltonian. A second method will then be exposed, with the goal of overcoming this unpleasant feature. The new EOB model, besides being now (as wished) a quadratic function of the momenta, also needs a smaller number of coefficients, with respect to the first method, to reproduce the NLO spin-spin coupling. Some strong-field predictions of this EOB Hamiltonian will be exposed and compared with other EOB models. In particular, I will show some plots of gauge invariant quantities at the last stable orbit. |
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Talk view |
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