Gravity Seminars

The inspiral phase of binary neutron stars (BNS) is significantly influenced by tidal interactions, particularly as the system nears merger and NS mode resonance makes the tide dynamical. The commonly used effective Love number approach is insufficient for modeling the dynamical tide, as it overlooks critical elements like tidal torque and the enhanced quadrupole radiation from resonance. It also fails to account for the "tidal spin"—the spin carried by the tide—and the associated Newtonian and relativistic dynamics. In the first half of the talk, we will present a new effective one-body model that incorporates these essential features, enhancing accuracy for spinning NSs where dynamical tides are strongest. In the second half, we will explore how nonlinear hydrodynamic effects further amplify dynamical tides. Nonlinear interactions can lower the frequency of the NS f-mode, amplifying its resonance. The NS’s g-mode may even enter a resonance locking phase, with its anharmonically shifted frequency tracking the decaying orbital frequency. This sustained resonance introduces significant phase corrections to the waveform. Accurately modeling these various tidal effects will be essential for performing faithful parameter estimation, constraining the NS equation of state, and testing theories of relativity.