标题： Morse理论中的弦Jacobi场 显示英文标题

标题： Stringy Jacobi fields in Morse theory

摘要： 我们考虑时空流形中由闭弦张成的曲面的变化。利用Nambo-Goto弦作用量，我们导出了测地曲面方程、产生Jacobi场的测地曲面偏差方程，并且像点粒子情况一样定义了测地曲面的指数形式，以讨论测地曲面上的共轭弦。 显示英文摘要

摘要： We consider the variation of the surface spanned by closed strings in a spacetime manifold. Using the Nambu-Goto string action, we induce the geodesic surface equation, the geodesic surface deviation equation which yields a Jacobi field, and we define the index form of a geodesic surface as in the case of point particles to discuss conjugate strings on the geodesic surface.