论文标题
在修改的远程引力中探索轴向对称性
Exploring Axial Symmetry in Modified Teleparallel Gravity
论文作者
论文摘要
轴向对称的空间在对旋转天体物理物体(如黑洞,星星等)的相对论描述中起着重要作用。在引力理论中,通过允许独立的连接组件,对称性关注的概念,不仅是指标,而是连接的引力理论,这些引力理论冒险超越了通常的riemannian几何形状。如最近发现的那样,在远程平行的几何形状中,轴向对称性可以在两个分支中实现,而其中只有一个具有连续的球形对称极限。在当前的论文中,我们考虑了非常通用的$ f(t,b,ϕ,x)$ teleparallear重力家族,其动作取决于扭转标量$ t $和边界术语$ b $,以及带有其动力学术语$ x $的标量字段$ ϕ $。由于可以将场方程分解为对称和反对称(自旋连接)部分,因此我们彻底分析了反对称方程,并寻找轴向间距的溶液,可以用作ansätze来应对田间方程的对称部分。特别是,我们发现与taub-nut度量的概括和缓慢旋转的kerr时空相对应的溶液。由于这项工作还涉及一个更广泛的问题,即如何确定远程平行性重力中的自旋连接,因此我们还表明,文献中提出的“关闭重力”的方法并不总是为反对称方程提供解决方案。
Axially symmetric spacetimes play an important role in the relativistic description of rotating astrophysical objects like black holes, stars, etc. In gravitational theories that venture beyond the usual Riemannian geometry by allowing independent connection components, the notion of symmetry concerns, not just the metric, but also the connection. As discovered recently, in teleparallel geometries, axial symmetry can be realised in two branches, while only one of these has a continuous spherically symmetric limit. In the current paper, we consider a very generic $f(T,B,ϕ,X)$ family of teleparallel gravities, whose action depends on the torsion scalar $T$ and the boundary term $B$, as well as a scalar field $ϕ$ with its kinetic term $X$. As the field equations can be decomposed into symmetric and antisymmetric (spin connection) parts, we thoroughly analyse the antisymmetric equations and look for solutions of axial spacetimes which could be used as ansätze to tackle the symmetric part of the field equations. In particular, we find solutions corresponding to a generalisation of the Taub-NUT metric, and the slowly rotating Kerr spacetime. Since this work also concerns a wider issue of how to determine the spin connection in teleparallel gravity, we also show that the method of "turning off gravity" proposed in the literature, does not always produce a solution to the antisymmetric equations.