Speaker : J. Steinhoff

Title : Dynamical tides in General Relativity

Abstract : Compact binaries are the most promising source for the network of advanced gravitational wave detectors, which demonstrated its abilities with the recent observation of a gravitational wave from a binary black hole merger. If the binary contains a neutron star, then the influence of tidal effects on the binary evolution can be large. The tidal bulge of the neutron star is usually assumed to follow the external tidal force almost instantly. However, this assumption breaks down if the varying tidal force is in resonance with an oscillation mode of the neutron star : the tides become dynamical. We discuss how in this case the neutron star can be modelled by an effective point particle with dynamical quadrupole degrees of freedom. The equations of motion take on the form of the Mathisson-Papapetrou-Dixon equations, completed by a dynamical equation for the quadrupole. The Hamiltonian in the extreme mass ratio case is derived. It is briefly discussed how this Hamiltonian and a post-Newtonian description of dynamical tides can be combined in the effective one body Hamiltonian, without giving rise to a pole at the light ring in the potentials.