The two most common initial data for vacuum axisymmetric spacetimes are the Brill and Teukolsky gravitational waves. The subsequent numerical evolution of these data exhibits distinct properties mainly associated with the critical gravitational collapse. A possible way of understanding these differences is first to look at the linear level, where the Brill waves have a multipolar structure, while the Teukolsky waves have a quadrupolar structure. Despite being structurally distinct at the linear and nonlinear levels, we show that these gravitational wave initial data share an unexpected similarity related to the distribution of ADM mass as a function of the initial wave's amplitude. More specifically, both configurations satisfy a nonextensive relation, commonly seen in systems governed by long range interactions.
Comment on "Arnowitt--Deser--Misner representation and Hamiltonian analysis of covariant renormalizable gravity" by M. Chaichian, M. Oksanen, A. Tureanu
本文对M. Chaichian,M. Oksanen,A. Tureanu(Eur. Phys. J. C 71,1657(2011))是不正确的;真正的约束代数与他们所声称的动量约束的选择不同。我们盲目接受他们的约束代数的正确性,导致我们得出结论,错误的是,作者提出的一些模型(共享相同的约束代数)在空间同构下不是不变的。我们用Noether第二定理“证明”了这一点(见论文的第一版),但是我们发现了计算中的一个错误。空间双同态的微分恒等式是完整的,因此它们的作用量是不变的;但在这种情况下,空间双同态的规范对称性不能与它们的代数相容。我们现在明确地证明,实际的代数约束是不同的,并简要地描述它如何影响发电机和规范变换的领域。
University of Vienna(维也纳大学);Beijing Institute for Mathematical Sciences and Applications(北京数学与交叉科学高等研究院);Center for Theoretical Physics, Polish Academy of Sciences(波兰科学院理论物理中心)
本文重新推导了Arnowitt-Deser-Misner方程,探讨了 lapse 零点的无害性,并分析了协变化的安德森-约克方程的因果性质,将解与初始数据的最大全局超曲面发展相关联。