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Stability of relativistic stars with scalar hairs
Physical Review D ( IF 4.6 ) Pub Date : 
Ryotaro Kase, Rampei Kimura, Seiga Sato, Shinji Tsujikawa

We study the stability of relativistic stars in scalar-tensor theories with a nonminimal coupling of the form F(ϕ)R, where F depends on a scalar field ϕ and R is the Ricci scalar. On a spherically symmetric and static background, we incorporate a perfect fluid minimally coupled to gravity as a form of the Schutz-Sorkin action. The odd-parity perturbation for the multipoles l2 is ghost-free under the condition F(ϕ)>0, with the speed of gravity equivalent to that of light. For even-parity perturbations with l2, there are three propagating degrees of freedom arising from the perfect-fluid, scalar-field, and gravity sectors. For l=0,1, the dynamical degrees of freedom reduce to two modes. We derive no-ghost conditions and the propagation speeds of these perturbations and apply them to concrete theories of hairy relativistic stars with F(ϕ)>0. As long as the perfect fluid satisfies a weak energy condition with a positive propagation speed squared cm2, there are neither ghost nor Laplacian instabilities for theories of spontaneous scalarization and Brans-Dicke (BD) theories with a BD parameter $\omega_{\rm BD}>-3/2$ (including f(R) gravity). In these theories, provided $0

中文翻译:

具有标量毛发的相对论恒星的稳定性

我们在标量张量理论中研究相对论恒星的稳定性,其形式为非最小耦合 Fϕ[R,在哪里 F 取决于标量场 ϕ[R是Ricci标量。在球形对称和静态背景下,我们引入了一种最小化与重力耦合的完美流体,作为Schutz-Sorkin动作的一种形式。多极的奇偶奇摄动2 在以下条件下无鬼影 Fϕ>0,其重力速度等于光速。对于偶数奇偶摄动2,由完美流体,标量场和重力扇区产生的三个传播自由度。对于=01个,动态自由度降低为两种模式。我们推导无鬼的条件和这些扰动的传播速度,并将其应用于具有毛细相对论的恒星的具体理论Fϕ>0。只要理想流体满足弱能量条件,且传播速度为正数C2,既没有鬼也不拉普拉斯不稳定用于与BD参数自发标量化和布兰斯-迪克(BD)的理论的理论$ \欧米加_ {\ RM BD}> - 3/2 $(包括F[R重力)。在这些理论中,提供了$ 0
更新日期:2020-09-23
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