Vacuum Spacetimes with Constant Weyl Eigenvalues

Spanish Relativity Meeting: almost 100 years after Einstein's revolution

Barnes, A.^1

School of Engineering and Applied Science, Aston Umiversity, Birmingham

B4 7ET, United Kingdom^1

关键词: Cosmological constants;    Curvature tensors;    Eigen-value;    Eigenvalues;    Group theoretic method;    Robinson;    Scalar invariants;    Type II;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/600/1/012067/pdf
DOI  :  10.1088/1742-6596/600/1/012067

来源: IOP

【 摘 要 】

Einstein spacetimes (that is vacuum spacetimes possibly with a non-zero cosmological constant Λ) with constant non-zero Weyl eigenvalues are considered. For type Petrov II & D this assumption allows one to prove that the non-repeated eigenvalue necessarily has the value 2Λ/3 and it turns out that the only possible spacetimes are some Kundt-waves considered by Lewandowski which are type II and a Robinson-Bertotti solution of type D. For Petrov type I the only solution turns out to be a homogeneous pure vacuum solution found long ago by Petrov using group theoretic methods. These results can be summarised by the statement that the only vacuum spacetimes with constant Weyl eigenvalues are either homogeneous or are Kundt spacetimes. This result is similar to that of Coley et al. who proved their result for general spacetimes under the assumption that all scalar invariants constructed from the curvature tensor and all its derivatives were constant.