论文标题
双重重力费用的注释
A note on dual gravitational charges
论文作者
论文摘要
双重引力电荷最近是使用协方差相空间方法从四个变量中的HOLST项计算出来的。我们强调，它们源自四型符号势中的精确3形式，该势能在度量变量中没有类似物。因此，存在将双重电荷设置为零的四四元势势的选择。该观察结果依赖于协变相空间方法的歧义。为了更多地阐明双重贡献，我们使用Kosmann变异来计算（准本地）汉密尔顿的指控，以进行任意差异性。我们获得了一个公式，可以全面说明为什么对哈密顿指控的双重贡献：（i）在空间无穷大的精确异构体和渐近对称性中消失； （ii）除了通常的BMS贡献外，未来零无穷大的渐近对称性持续存在。最后，我们指出，双重引力电荷可以使用基于共同体方法的Barnich-Brandt处方平均得出，并且对渐近对称性的相同考虑。
Dual gravitational charges have been recently computed from the Holst term in tetrad variables using covariant phase space methods. We highlight that they originate from an exact 3-form in the tetrad symplectic potential that has no analogue in metric variables. Hence there exists a choice of the tetrad symplectic potential that sets the dual charges to zero. This observation relies on the ambiguity of the covariant phase space methods. To shed more light on the dual contributions, we use the Kosmann variation to compute (quasi-local) Hamiltonian charges for arbitrary diffeomorphisms. We obtain a formula that illustrates comprehensively why the dual contribution to the Hamiltonian charges: (i) vanishes for exact isometries and asymptotic symmetries at spatial infinity; (ii) persists for asymptotic symmetries at future null infinity, in addition to the usual BMS contribution. Finally, we point out that dual gravitational charges can be equally derived using the Barnich-Brandt prescription based on cohomological methods, and that the same considerations on asymptotic symmetries apply.
