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Classical non-adiabatic angles. (English) Zbl 0646.70010

Summary: If a family of tori in phase space is driven by a time-dependent Hamiltonian flow in such a way as to return after some time to the original family, there generally results a shift in the angle variables. One realisation of this process is in the cyclic adiabatic change of a classical Hamiltonian, and the angle change has previously been shown to separate naturally into a dynamical part and a geometrical part. Here the same geometrical angle change is extracted when the return is achieved non-adiabatically, and the ‘dynamical’ remainder calculated. Two examples are given: the precession of a spin and the rotation of phase-space ellipses.

MSC:

70G10 Generalized coordinates; event, impulse-energy, configuration, state, or phase space for problems in mechanics
37J99 Dynamical aspects of finite-dimensional Hamiltonian and Lagrangian systems
70K05 Phase plane analysis, limit cycles for nonlinear problems in mechanics