标题： 正则化4D爱因斯坦-高斯-博内引力中具有统一相互作用状态方程的夸克星 显示英文标题

标题： Quark stars with a unified interacting equation of state in regularized 4D Einstein-Gauss-Bonnet gravity

摘要： 自四维爱因斯坦高斯-博内（4DEGB）引力与标量场耦合的适定极限 $D\rightarrow 4$ 被推导出以来，人们对其作为爱因斯坦广义相对论替代方案的兴趣逐渐增加。我们利用修改后的托尔曼-奥本海默-沃尔科夫（TOV）方程来研究4DEGB引力下的夸克星结构，并采用一种新颖的相互作用夸克物质状态方程来描述其恒星结构。我们发现，增加高斯-博内耦合常数 $\alpha$ 或相互作用参数 $\lambda$ 都会倾向于增大由该理论描述的夸克星的质量-半径曲线，从而使得给定的中心压力可以支持更大的夸克星。这些结果同样适用于 $\lambda < 0$ 的情况，在这种情况下，增加相互作用效应的幅度反而会减小质量和半径。此外，我们在两种情况下都解析地确定了临界中心压力，低于此压力时，由于压力函数没有根，夸克星解不存在。最有趣的是，我们发现夸克星可以在广义相对论的布赫达尔界限和史瓦西半径 $R=2M$ 之下存在，这是因为4DEGB引力中黑洞与致密星之间不存在质量间隙。即使对于很小的 $\alpha$，仍处于当前观测限制范围内，我们发现该理论中的夸克星解能够描述极端致密天体（ECOs），即其半径小于广义相对论所允许的范围的天体。 显示英文摘要

摘要： Since the derivation of a well-defined $D\rightarrow 4$ limit for 4D Einstein Gauss-Bonnet (4DEGB) gravity coupled to a scalar field, there has been interest in testing it as an alternative to Einstein's general theory of relativity. Using the Tolman-Oppenheimer-Volkoff (TOV) equations modified for 4DEGB gravity, we model the stellar structure of quark stars using a novel interacting quark matter equation of state. We find that increasing the Gauss-Bonnet coupling constant $\alpha$ or the interaction parameter $\lambda$ both tend to increase the mass-radius profiles of quark stars described by this theory, allowing a given central pressure to support larger quark stars in general. These results logically extend to cases where $\lambda < 0$, in which increasing the magnitude of the interaction effects instead diminishes masses and radii. We also analytically identify a critical central pressure in both regimes, below which no quark star solutions exist due to the pressure function having no roots. Most interestingly, we find that quark stars can exist below the general relativistic Buchdahl bound and Schwarzschild radius $R=2M$, due to the lack of a mass gap between black holes and compact stars in 4DEGB. Even for small $\alpha$ well within current observational constraints, we find that quark star solutions in this theory can describe Extreme Compact Objects (ECOs), objects whose radii are smaller than what is allowed by general relativity.