标题： 标量-张量理论中的类光冲击波 显示英文标题

标题： Light-like shockwaves in scalar-tensor theories

摘要： 电磁冲击波和引力波都以光速传播。 如果它们携带显著的能量-动量，这将改变它们所通过的时空性质。 这可以通过在由奇异的零超曲面分隔的时空区域之间的连接条件来描述。 我们推导了乔丹框架下的布兰斯-迪克理论的通用连接条件，探索了一种基于横向矢量而非法向量的形式，该形式可以应用于任何类型的超曲面。 在非零超曲面的特殊情况中，我们得到一个广义的兰佐斯方程，在该方程中，外曲率的跃变由分布式的能量-动量张量以及标量的横向导数的跃变共同驱动。 在零超曲面的情况下，分布源被分解为表面密度、电流和压力。 然而，后者应根据标量连接条件而消失。 显示英文摘要

摘要： Both electromagnetic shock-waves and gravitational waves propagate with the speed of light. If they carry significant energy-momentum, this will change the properties of the space-time they propagate through. This can be described in terms of the junction conditions between space-time regions separated by a singular, null hypersurface. We derived generic junction conditions for Brans-Dicke theory in the Jordan frame, exploring a formalism based on a transverse vector, rather than normal, which can be applied to any type of hypersurfaces. In the particular case of a non-null hypersurface we obtain a generalised Lanczos equation, in which the jump of the extrinsic curvature is sourced by both the distributional energy-momentum tensor and by the jump in the transverse derivative of the scalar. In the case of null hypersurfaces, the distributional source is decomposed into surface density, current and pressure. The latter however ought to vanish by virtue of the scalar junction condition.