| he semiclassical coherent state propagator is not free from the problem of caustics. These are singular points along complex classical trajectories, specified by the initial and final coherent states and by the propagation time, where the usual quadratic approximation fails, leading to divergences in the semiclassical formula. In this talk we show how the Maslov method can be used to derive third order approximations for the propagator that remain finite in the vicinity of caustics. We apply the improved formula to two model systems: the one-dimensional quartic oscillator and a two-dimensional chaotic system. |
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