论文标题
与非微小标源耦合的紧凑型恒星的不稳定性
Instability of compact stars with a nonminimal scalar-derivative coupling
论文作者
论文摘要
对于一种理论，即标量字段$ ϕ $与形式$ $ ϕ \，g_ {μν} \ nabla^μ\ nabla^μ\ nabla^c nabla^c nabla^c nabla^c nabla^c nabla^c nabla^c nabla^c nabla^c nabla^c nabla^c nabla^c nabla^c nabla^球的形式与静态的稳定性相关的稳定性的稳定性的稳定性的稳定性，在他们的内部。我们研究了具有径向场依赖性$ ϕ（r）$对奇数和偶数扰动的这种毛茸茸的解决方案的稳定性。我们表明，对于星形紧凑型$ {\ cal c} $小于$ 1/3 $，它们很容易发生与沿角方向相关的标量场传播相关的偶数扰动。即使对于$ {\ cal c}> 1/3 $，毛茸茸的星形解决方案也受到幽灵不稳定性的影响。我们还发现，由于恒星内部内部扰动$Δϕ $的非标准繁殖，即使是具有消失背景场导数的另一个分支对于正面的完美流体压力也是不稳定的。因此，在没有标准动力学术语的衍生耦合理论中，没有稳定的星形构型，包括相对论和非依赖性的紧凑对象。
For a theory in which a scalar field $ϕ$ has a nonminimal derivative coupling to the Einstein tensor $G_{μν}$ of the form $ϕ\,G_{μν}\nabla^μ\nabla^ν ϕ$, it is known that there exists a branch of static and spherically-symmetric relativistic stars endowed with a scalar hair in their interiors. We study the stability of such hairy solutions with a radial field dependence $ϕ(r)$ against odd- and even-parity perturbations. We show that, for the star compactness ${\cal C}$ smaller than $1/3$, they are prone to Laplacian instabilities of the even-parity perturbation associated with the scalar-field propagation along an angular direction. Even for ${\cal C}>1/3$, the hairy star solutions are subject to ghost instabilities. We also find that even the other branch with a vanishing background field derivative is unstable for a positive perfect-fluid pressure, due to nonstandard propagation of the field perturbation $δϕ$ inside the star. Thus, there are no stable star configurations in derivative coupling theory without a standard kinetic term, including both relativistic and nonrelativistic compact objects.
