论文标题
Levi-Civita时空的几何和物理解释就Komar质量密度而言
Geometrical and physical interpretation of the Levi-Civita spacetime in terms of the Komar mass density
论文作者
论文摘要
我们重新审视了圆柱形对称,静态真空levi-civita公制的解释,这是Weyl,Einstein-Rosen或Kasner样坐标。尽管有无限的轴源,但我们还是通过紧凑型和随后炸毁紧凑型半径来得出其Komar质量密度。我们表明,在爱因斯坦 - 罗森框架中计算出的komar质量密度$μ_k$,当用作度量参数时,具有许多优点。它消除了参数空间的双重覆盖范围,在平面时段消失,当较小时,它对应于无限字符串的质量密度。在对本地和全球几何形状进行了全面分析之后,我们继续对Levi-Civita时空进行物理解释。首先,我们表明牛顿引力具有吸引力,其幅度以所有正$μ_K$单调增加,这是渐近的“径向”方向上适当距离的倒数。其次,我们揭示了附近的大地测量学之间的潮汐力(因此在爱因斯坦的意义上)达到$μ_k= 1/2 $的最大值,然后渐近地降低至零。因此,从物理的角度来看,Levi-Civita时空的Komar质量密度包括两个贡献:牛顿重力和加速效应。 $μ_k$的增加增强了牛顿的重力,但也使野外线越来越平行,最终通过等效原理将牛顿重力转化为纯净的加速度场,而Levi-civita spacetime则变成了扁平的rindler-like spaceTime。在几何图片中,$μ_k$从零增加到$ \ infty $将时空的平面部分变形为越来越深的漏斗,最终变成了圆柱形拓扑。
We revisit the interpretation of the cylindrically symmetric, static vacuum Levi-Civita metric, known in either Weyl, Einstein-Rosen, or Kasner-like coordinates. Despite the infinite axis source, we derive its Komar mass density through a compactification and subsequent blowing up of the compactification radius. We show that, the Komar mass density $μ_K$ calculated in the Einstein-Rosen frame, when employed as the metric parameter, has a number of advantages. It eliminates double coverages of the parameter space, vanishes in flat spacetime and when small, it corresponds to the mass density of an infinite string. After a comprehensive analysis of the local and global geometry, we proceed with the physical interpretation of the Levi-Civita spacetime. First we show that the Newtonian gravitational force is attractive and its magnitude increases monotonically with all positive $μ_K$, asymptoting to the inverse of the the proper distance in the "radial" direction. Second, we reveal that the tidal force between nearby geodesics (hence gravity in the Einsteinian sense) attains a maximum at $μ_K=1/2$ and then decreases asymptotically to zero. Hence, from a physical point of view the Komar mass density of the Levi-Civita spacetime encompasses two contributions: Newtonian gravity and acceleration effects. An increase in $μ_K$ strengthens Newtonian gravity but also drags the field lines increasingly parallel, eventually transforming Newtonian gravity through the equivalence principle into a pure acceleration field and the Levi-Civita spacetime into a flat Rindler-like spacetime. In a geometric picture the increase of $μ_K$ from zero to $\infty$ deforms the planar sections of the spacetime into ever deepening funnels, eventually degenerating into cylindrical topology.