Bounds on the mass-to-radius ratio for non-compact field configurations
Bounds on the mass-to-radius ratio for non-compact field configurations
复制标题
非紧场配置的质量半径比的界限
DOI：
10.1088/0264-9381/24/23/021
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
S. Hod
中科院分区：
文献类型：
--
作者：
S. Hod
众所周知，能量密度单调减小的球对称致密恒星，其质量半径比有一个上界，2M/R≥8/9。但是，字段配置通常不会紧凑。在这里，我们研究了非紧静态构型，其物质场具有缓慢的全局空间衰减，受幂律行为的限制。这些物质分布没有明显的边界。我们推导了基本比率maxr{2m(r)/r}的上界，该上界在整个系统中都是有效的。在其最简单的形式中，边界意味着在任何时空区域中，如果径向压力增加或减少的速度不快于某个幂律r - (γ+4)，则有2m(r)/r≤(2 + 2γ)/(3 + 2γ)。（当γ≥0时，界退化为2m(r)/r≤2/3。）在它的一般版本中，界用两个物理参数来表示：物质场的空间衰减率和压力张量的迹与局部能量密度的最高出现率。
It is well known that a spherically symmetric compact star whose energy density decreases monotonically possesses an upper bound on its mass-to-radius ratio, 2M/R ⩽ 8/9. However, field configurations typically will not be compact. Here we investigate non-compact static configurations whose matter fields have a slow global spatial decay, bounded by a power law behavior. These matter distributions have no sharp boundaries. We derive an upper bound on the fundamental ratio maxr{2m(r)/r} which is valid throughout the bulk. In its simplest form, the bound implies that in any region of spacetime in which the radial pressure increases, or alternatively decreases no faster than some power law r−(γ+4), one has 2m(r)/r ⩽ (2 + 2γ)/(3 + 2γ). (For γ ⩽ 0 the bound degenerates to 2m(r)/r ⩽ 2/3.) In its general version, the bound is expressed in terms of two physical parameters: the spatial decaying rate of the matter fields, and the highest occurring ratio of the trace of the pressure tensor to the local energy density.