Reviving the shear-free perfect fluid conjecture in general relativity

被引:0
|
作者
Sikhonde, Muzikayise E. [1 ]
Dunsby, Peter K. S. [1 ]
机构
[1] Univ Cape Town, Dept Math & Appl Math, Cosmol & Grav Grp, ZA-7701 Cape Town, South Africa
关键词
shear-free; vorticity; perfect fluid; Killing vector; lie derivative;
D O I
10.1088/1361-6382/aa95ad
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Employing a Mathematica symbolic computer algebra package called xTensor, we present (1 + 3)-covariant special case proofs of the shear-free perfect fluid conjecture in general relativity. We first present the case where the pressure is constant, and where the acceleration is parallel to the vorticity vector. These cases were first presented in their covariant form by Senovilla et al. We then provide a covariant proof for the case where the acceleration and vorticity vectors are orthogonal, which leads to the existence of a Killing vector along the vorticity. This Killing vector satisfies the new constraint equations resulting from the vanishing of the shear. Furthermore, it is shown that in order for the conjecture to be true, this Killing vector must have a vanishing spatially projected directional covariant derivative along the velocity vector field. This in turn implies the existence of another basic vector field along the direction of the vorticity for the conjecture to hold. Finally, we show that in general, there exists a basic vector field parallel to the acceleration for which the conjecture is true.
引用
收藏
页数:39
相关论文
共 50 条