New perspectives on neutron star and black hole spectroscopy and dynamic tides

TL;DR

This paper introduces a formalism for tidal interactions in neutron stars and black holes using a linear response function, bridging static Love numbers and dynamic tides, with implications for gravitational wave astronomy.

Contribution

It develops a harmonic oscillator model for neutron star tides and explores black hole responses, providing a unified framework for static and dynamic tidal effects.

Findings

Neutron star internal dynamics can be modeled as harmonic oscillators.

The response function acts as a gravitational spectrum analogous to atomic spectra.

Preliminary black hole response analysis suggests similar formalism can be applied.

Abstract

We elaborate on a powerful tidal interaction formalism where the multipole dynamics is kept generic and encoded in a linear response function. This response function is the gravitational counterpart of the atomic spectrum and can become of similar importance with the rise of gravitational wave astronomy. We find that the internal dynamics of nonrotating neutron stars admit a harmonic oscillator formulation yielding a simple interpretation of tides. A preliminary investigation of the black holes case is given. Our results fill the gap between Love numbers and dynamic tides.