Dynamical tides in neutron stars with first-order phase transitions: the role of the discontinuity mode

During the late stages of a binary neutron star inspiral, dynamical tides induced in each star by its companion become significant. These tides can excite oscillation modes within the neutron stars, affecting the gravitational wave signal emitted during the inspiral. If a neutron star undergoes a first-order phase transition in its core, it can develop a sharp density discontinuity. This discontinuity gives rise to a unique oscillation modes, which we have studied with Jonas P. Pereira, Lucas Tonetto, J. Leszek Zdunik and Paweł Haensel.

In arXiv:2504.19962, we show that these discontinuity modes (g-mode), intrinsically associated with first-order phase transitions and buoyancy, can rival the contribution of the fundamental f-mode, and be relevant even at the design sensitivity of current second-generation GW detectors in the most optimistic cases.