The theory governing the strong nuclear force—quantum chromodynamics—predicts that at sufficiently high energy densities, hadronic nuclear matter undergoes a deconfinement transition to a new phase of quarks and gluons¹. Although this has been observed in ultrarelativistic heavy-ion collisions^2,3, it is currently an open question whether quark matter exists inside neutron stars⁴. By combining astrophysical observations and theoretical ab initio calculations in a model-independent way, we find that the inferred properties of matter in the cores of neutron stars with mass corresponding to 1.4 solar masses (M_⊙) are compatible with nuclear model calculations. However, the matter in the interior of maximally massive stable neutron stars exhibits characteristics of the deconfined phase, which we interpret as evidence for the presence of quark-matter cores. For the heaviest reliably observed neutron stars^5,6 with mass M ≈ 2M_⊙, the presence of quark matter is found to be linked to the behaviour of the speed of sound c_s in strongly interacting matter. If the conformal bound \({c}_{\rm{s}}^{2}\le 1/3\) (ref. ⁷) is not strongly violated, massive neutron stars are predicted to have sizable quark-matter cores. This finding has important implications for the phenomenology of neutron stars and affects the dynamics of neutron star mergers with at least one sufficiently massive participant.

有关强核力的理论（量子色动力学）预测，在足够高的能量密度下，强子性核物质将发生脱约束作用过渡到夸克和胶子的新阶段¹。尽管这已经在超相对论重离子碰撞^2，3中观察到，但目前在中子星⁴内是否存在夸克物质是一个悬而未决的问题。通过在模型无关的方式原理计算天体物理观测和理论相结合AB，我们发现，无论在中子星对应于1.4倍太阳质量的质量核心的推断性（中号_⊙）与核模型计算兼容。然而，最大质量的稳定中子星内部的物质表现出非限定相的特征，我们将其解释为存在夸克质核的证据。对于最重的可靠观测中子星^5,6与质谱中号 ≈2中号_⊙，夸克物质的存在被发现要被链接到的声音的速度的行为Ç_小号在物质强烈相互作用。如果保形边界\（{c} _ {\ rm {s}} ^ {2} \ le 1/3 \）（参考⁷）并未受到严重侵犯，据预测，大量中子星具有相当大的夸克质核。这一发现对中子星的现象学具有重要的意义，并影响了至少有一个足够大的参与者的中子星合并的动力学。