论文标题
部分可观测时空混沌系统的无模型预测
Stability of neutron stars in Horndeski theories with Gauss-Bonnet couplings
论文作者
论文摘要
在包含标量耦合的Horndeski理论中，与高斯曲率（GB）曲率不变性$ r _ {\ rm Gb}^2 $，我们研究了中性星（NS）溶液的存在和线性稳定性在静态和球形的背景上。对于形式的标量gb耦合，$αξ（ϕ）r _ {\ rm gb}^2 $，其中$ξ$是标量场$ ϕ $的函数，存在线性稳定的星星，具有非平量表的线性稳定性，而无需不稳定性，而无需不稳定性，则无法将上限限制在不断变化的coupl counts $ $ $ $ | | | | | | | | | | | | | | | | | | |为了实现线性（或膨胀）GB耦合$α_ {\ rm gb} ϕr _ {\ rm gb}^2 $带有典型状态核方程式的最大NSS，我们获得了理论的上限上限$ \ sqrt {|α_ {| rm rm g}^0。这比观察到来自含有NSS的二进制的重力波获得的重力比获得的要紧。我们还结合了立方顺序的标量衍生物相互作用，除标量-GB耦合外，与RICCI标量与RICCI标量偶联以外的四分之一衍生物耦合，并表明NS解决方案具有非平凡标量型，使所有线性稳定性都满足所有线性稳定性条件，并且在某些coupling coupling conpling conpling conpling and ranges中都存在所有线性稳定性条件。在从kaluza-klein还原获得的正则四维爱因斯坦GB重力中，并适当重新恢复了GB耦合常数，我们发现该理论中的NSS遭受了强烈的耦合问题以及持续性关系的laplacian不稳定。我们还在Power-Law $ F（r _ {\ rm gb}^2）$模型中研究了具有非平凡标量曲线的NS解决方案，并证明它们在恒星的内部是病态的，并且被幽灵不稳定性以及恒星外部的渐近强耦合问题而受到困扰。
In Horndeski theories containing a scalar coupling with the Gauss-Bonnet (GB) curvature invariant $R_{\rm GB}^2$, we study the existence and linear stability of neutron star (NS) solutions on a static and spherically symmetric background. For a scalar-GB coupling of the form $αξ(ϕ) R_{\rm GB}^2$, where $ξ$ is a function of the scalar field $ϕ$, the existence of linearly stable stars with a nontrivial scalar profile without instabilities puts an upper bound on the strength of the dimensionless coupling constant $|α|$. To realize maximum masses of NSs for a linear (or dilatonic) GB coupling $α_{\rm GB}ϕR_{\rm GB}^2$ with typical nuclear equations of state, we obtain the theoretical upper limit $\sqrt{|α_{\rm GB}|}<0.7~{\rm km}$. This is tighter than those obtained by the observations of gravitational waves emitted from binaries containing NSs. We also incorporate cubic-order scalar derivative interactions, quartic derivative couplings with nonminimal couplings to a Ricci scalar besides the scalar-GB coupling and show that NS solutions with a nontrivial scalar profile satisfying all the linear stability conditions are present for certain ranges of the coupling constants. In regularized 4-dimensional Einstein-GB gravity obtained from a Kaluza-Klein reduction with an appropriate rescaling of the GB coupling constant, we find that NSs in this theory suffer from a strong coupling problem as well as Laplacian instability of even-parity perturbations. We also study NS solutions with a nontrivial scalar profile in power-law $F(R_{\rm GB}^2)$ models, and show that they are pathological in the interior of stars and plagued by ghost instability together with the asymptotic strong coupling problem in the exterior of stars.
