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arXiv · 2609.05118

Probing Neutron Star Equation of State Universality with Gravitational Waves

Praveer Tiwari·Ajit Kumar Mehta·K. G. Arun
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Abstract

Current neutron star equation-of-state inferences assume that a common equation of state describes all neutron stars. However, {poorly understood dense-matter physics may give rise to distinct long-lived stellar subpopulations following different mass--tidal-deformability relations, invalidating this assumption. In this Letter, we demonstrate that next-generation gravitational-wave observatories enable neutron star equation-of-state universality to be transformed from an assumption into a testable hypothesis. By combining hierarchical Bayesian inference with a piecewise-polytropic parametrization of the neutron star equation of state, we establish a framework for testing equation-of-state universality with next-generation gravitational-wave observatories. We find that about 30 (50) loud binary neutron star mergers with network SNRs above 100 are sufficient to provide compelling evidence for departures from equation-of-state universality, even if only 20% (10%) of the population exhibits one of the representative non-universality parametrizations considered here.

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Praveer Tiwari, Ajit Kumar Mehta, K. G. Arun. 2026-09-04. Probing Neutron Star Equation of State Universality with Gravitational Waves. https://arxiv.org/abs/2609.05118

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