Gravitational-wave Signature of a First-order Quantum Chromodynamics Phase Transition in Core-Collapse Supernovae

TL;DR

This paper demonstrates that a first-order QCD phase transition in core-collapse supernovae produces a strong, high-frequency gravitational wave burst, offering a potential observational signature of such a phase transition.

Contribution

The study provides the first simulation-based evidence that a QCD phase transition causes a distinctive GW burst in supernovae, with detailed spectral and energetic characteristics.

Findings

GW burst amplitude is ~30 times larger than typical post-bounce signals

Peak GW frequency shifts dramatically after the phase transition

GW energy exceeds other emission episodes by three orders of magnitude

Abstract

A first-order quantum chromodynamics (QCD) phase transition (PT) may take place in the protocompact star (PCS) produced by a core-collapse supernova (CCSN). In this work, we study the consequences of such a PT in a non-rotating CCSN with axisymmetric hydrodynamic simulations. We find that the PT leads to the collapse of the PCS and results in a loud burst of gravitational waves (GWs). The amplitude of this GW burst is $\sim30$ times larger than the post-bounce GW signal normally found for non-rotating CCSN. It shows a broad peak at high frequencies ($\sim2500-4000$ Hz) in the spectrum, has a duration of $\lesssim5 {\rm ms}$, and carries $\sim3$ orders of magnitude more energy than the other episodes. Also, the peak frequency of the PCS oscillation increases dramatically after the PT-induced collapse. In addition to a second neutrino burst, the GW signal, if detected by the ground-based GW detectors, is decisive evidence of the first-order QCD PT inside CCSNe and provides key information about the structure and dynamics of the PCS.