标题： 混沌在夹层pp波中的弥散 显示英文标题

标题： Smearing of chaos in sandwich pp-waves

摘要： 最近的结果展示了非均匀真空pp波解中测地线的混沌行为，这些结果被推广了。 在这里，我们集中研究非均匀夹层pp波中的运动，并表明当这些引力波的持续时间减少时，混沌行为会变得模糊。 随着任何测地线径向反弹次数的减少，结果趋向于无限的通道变得模糊，因此表征混沌的初始条件的分形结构在越来越低的层次上被截断。 在冲激波的极限情况下，运动是完全非混沌的。 这是通过给出一种简单的显式形式的测地线来证明的，这种形式允许物理解释，并展示了聚焦效应。 结果显示，一个测试粒子的圆在冲激作用下会被变形为横向平面上的一族闭合的内摆线曲线。 这些曲线在纵向方向上被变形，使得特定的闭合焦面形成。 显示英文摘要

摘要： Recent results demonstrating the chaotic behavior of geodesics in non-homogeneous vacuum pp-wave solutions are generalized. Here we concentrate on motion in non-homogeneous sandwich pp-waves and show that chaos smears as the duration of these gravitational waves is reduced. As the number of radial bounces of any geodesic decreases, the outcome channels to infinity become fuzzy, and thus the fractal structure of the initial conditions characterizing chaos is cut at lower and lower levels. In the limit of impulsive waves, the motion is fully non-chaotic. This is proved by presenting the geodesics in a simple explicit form which permits a physical interpretation, and demonstrates the focusing effect. It is shown that a circle of test particles is deformed by the impulse into a family of closed hypotrochoidal curves in the transversal plane. These are deformed in the longitudinal direction in such a way that a specific closed caustic surface is formed.