Séminaire / Seminar GReCO |
| « On the Unreasonable Accuracy of the post-Newtonian Approximation » |
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N. Yunes |
| The post-Newtonian (PN) approximation is one of the preferred methods to solve t he Einstein equations iteratively in the weak-gravity/slow-motion regime. Recent numerical comparisons, however, suggest the PN approximation might work, in fact, too well, perhaps even well beyond this regime. This surprise has prompted the search for the formal region of validity of PN theory, which can be studied through the theory of optimal asymptotic expansions. In this talk, I will discuss how to find this region by applying asymptotic tools to the PN expansion and numerical approximation to the energy flux of extreme-mass ratio, quasi-circular inspirals. Although I shall here focus on one specific system, the method developed sets the foundations for a new type of comparison between numerical results and PN theory, allowing for retrieval of information unavailable by any other means. In particular, the application of this method to other PN resummation techni ques, such as Pade or Chebyshev, may settle whether such methods truly accelerat e the convergence of PN Taylor expansions. |
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lundi 9 juin 2008 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |