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Exact results for the ionization of a model quantum system

2000; Institute of Physics; Volume: 33; Issue: 36 Linguagem: Inglês

10.1088/0305-4470/33/36/303

1361-6447

Ovidiu Costin, Joel L. Lebowitz, Ovidiu Costin, A. Rokhlenko,

Spectroscopy and Quantum Chemical Studies

We prove that a model atom having one bound state will be fully ionized by a time periodic potential of arbitrary strength r and frequency ω. Starting with the system in the bound state, the survival probability is for small r given by e-Γt for times of order Γ-1 ~r-2n, where n is the minimum number of `photons' required for ionization (with large modifications at resonances). For late times the decay is as t-3 with the power law modulated by oscillations. As r increases, the time over which there is exponential decay becomes shorter and the power law behaviour starts earlier. Results are for a parametrically excited one-dimensional system with zero-range potential but comparison with analytical works and with experiments indicates that many features are general.