The trace anomaly $\mathrm{\Delta }$ is an important quantity that measures the broken conformal symmetry in neutron star matter. In this work, we present quasiuniversal relations that connect the stellar profile of $\mathrm{\Delta }$ to the compactness, moment of inertia, and tidal deformability of neutron stars. We apply the quasiuniversal relations to determine the trace anomaly profiles for PSR $\mathrm{J}0030+0451$ and PSR $\mathrm{J}0740+6620$ based on their mass-radius measurements. We also analyze PSR J0737-3039A according to its moment of inertia inferred from Bayesian modeling of nuclear equation of state. A recent multimessenger constraint on the tidal deformability is also studied, resulting in an estimate value of the trace anomaly ${\mathrm{\Delta }}_c=0.1770_{-0.0432}^{+0.0365}$ at the center of a $1.4M_{\odot }$ canonical neutron star. It is expected that more precise observations from both electromagnetic and gravitational-wave channels in the future will provide tighter constraints on the behavior of $\mathrm{\Delta }$ inside neutron stars.

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• Neutron stars & pulsars
• Numerical simulations in gravitation & astrophysics