Reading the physics of matter at its limit.

The same nuclear force that binds a finite nucleus also supports a neutron star. We construct relativistic mean-field interactions — G3, IOPB-I, and NITR — fitted to nuclear masses, radii and saturation properties, then use that equation of state for the stellar structure problem. The question is whether a model that describes nuclei still satisfies the two-solar-mass pulsar limit and the tidal deformability measured in GW170817.

Many neutron-star observables are tightly correlated. A single tidal measurement can therefore be turned, through EoS-insensitive relations, into bounds on radius and on the moment of inertia of PSR J0737−3039A. In that sense a gravitational-wave event is a nuclear-physics experiment, provided the theory connecting the two is under control.

Oscillation modes are a second window on the same physics. f- and p-mode frequencies, computed in the Cowling approximation and in linearized general relativity, track nuclear parameters such as the slope of the symmetry energy. Universal relations between quasinormal modes and tidal deformability give a handle that does not lean on any one equation of state.

The core need not be purely nucleonic. Hyperons and Δ-baryons soften the equation of state and shift the spectrum; a second fluid of WIMP or fermionic dark matter does the same. Those shifts have been compared with GW170817 posteriors and with compact objects such as PSR J0952−0607. Figures from the papers, and the full list, are on the publications page.