Megahertz Gravitational Waves from Neutron Star Mergers

TL;DR

This paper predicts that neutron star mergers could produce megahertz gravitational waves due to quantum chromodynamics phase transitions, offering a new observational window into extreme matter conditions.

Contribution

It introduces the possibility of megahertz gravitational wave signals arising from QCD phase transitions during neutron star mergers, expanding the scope of gravitational wave astronomy.

Findings

Megahertz gravitational waves could originate from QCD phase transitions.

Estimated signal amplitudes are within reach of future detectors.

Neutron star mergers can probe high-density QCD phenomena.

Abstract

Neutron star mergers provide a unique laboratory for the study of strong-field gravity coupled to quantum chromodynamics in extreme conditions. The frequencies and amplitudes of the resulting gravitational waves encode invaluable information about the merger. Simulations to date have shown that these frequencies lie in the kilohertz range. They have also shown that, if quantum chromodynamics possesses a first-order phase transition at high baryon density, then this is likely to be accessed during the merger dynamics. Here we show that this would result in the nucleation of superheated and/or supercompressed bubbles whose subsequent dynamics would produce gravitational waves in the megahertz range. We estimate the amplitude of this signal and compare it to the sensitivity of planned future detectors.