What are action-angle variables and how do they relate to coordinates?

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SUMMARY

Action-angle variables, also known as action-angle coordinates, are a mathematical framework used in classical mechanics to simplify the analysis of dynamical systems. They provide a way to describe periodic motion by separating the action, which quantifies the energy of the system, from the angle, which represents the phase of the motion. This approach is particularly useful in Hamiltonian mechanics, allowing for the integration of equations of motion in a more straightforward manner. The concept is foundational in areas such as celestial mechanics and quantum mechanics.

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Physicists, mathematicians, and students studying classical mechanics or dynamical systems will benefit from this discussion, particularly those interested in advanced topics like Hamiltonian mechanics and periodic motion analysis.

LarryS
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I'm looking for one clear, simple mathematical definition of action-angle variables. I believe they are also called action-angle coordinates. As always, thanks in advance.
 
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