Instability of compact stars with a nonminimal scalar-derivative coupling
Instability of compact stars with a nonminimal scalar-derivative coupling
复制标题
DOI：
10.1088/1475-7516/2021/01/008
复制
发表时间：
2021-01-01
影响因子：
6.4
通讯作者：
Tsujikawa, Shinji
中科院分区：
文献类型：
--
作者：
Kase, Ryotaro;Tsujikawa, Shinji
对于一个标量场与爱因斯坦张量G（mu nu），1有非最小导数耦合的理论，其形式为φ G（mu nu）del（mu）del（nu）phi，已知存在静态球对称相对论恒星的分支，内部有一根标量头发。我们研究了径向场依赖性φ（r）对奇宇称和偶宇称扰动的毛状解的稳定性。结果表明，当星星紧度C小于1/3时，标量场沿着角向传播时，偶宇称微扰容易发生拉普拉斯不稳定性.即使对于C > 1/3，毛状星星的解决方案是受鬼不稳定性。我们还发现，即使是另一个分支与消失的背景场导数是不稳定的一个积极的理想流体压力，由于非标准传播的星星内部的场扰动60。因此，在导数耦合理论中，没有标准的动力学项，就没有稳定的星星构型，包括相对论和非相对论致密天体。
For a theory in which a scalar field has a nonminimal derivative coupling to the Einstein tensor G(mu nu), 1 of the form phi G(mu nu)del(mu)del(nu)phi, 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 phi(r) against odd- and even-parity perturbations. We show that, for the star compactness 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 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 60 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.