Beyond the linear tide: impact of the non-linear tidal response of neutron stars on gravitational waveforms from binary inspirals

Understand

Tidal interactions in coalescing binary neutron stars modify the dynamics of the inspiral and hence imprint a signature on their gravitational wave (GW) signals in the form of an extra phase shift.

• We need accurate models for the tidal phase shift in order to constrain the supranuclear equation of state from observations.
• In previous studies, GW waveform models were typically constructed by treating the tide as a linear response to a perturbing tidal field.
• In this work, we incorporate non-linear corrections due to hydrodynamic three- and four-mode interactions and show how they can improve the accuracy and explanatory power of waveform models.