Semiclassical dynamics of strongly driven systems

Summary form only given.Approximate analytical solutions of the time-dependent Schrodinger equation for a system interacting with strong time-dependent external fields are the cornerstones of our understanding of strong-field phenomena. For example, the Keldysh-type solutions have been crucial in forming the modern paradigm of intense laser-atom physics and, reincarnated in recent re-collision models, provide a clear and unifying physical picture of such diverse effects as high-harmonic generation, creation of high-energy electrons, and nonsequential two-electron multiphoton ionization. The major problem of analytical solutions is the difficulty in treating both the binding potential and the external field equally and nonperturbatively. We develop a semiclassical approach that deals with this difficulty and can be applied to a broad class of problems in different areas of physics. For intense laser-atom physics, it treats both atomic and laser potential equally and has rigorously defined range of applicability. The most interesting and general applications of our method are to the class of problems where a quantum system with slow field-free dynamics faces a fast-oscillating external field.