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Action-Angle
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1-Dimensional CT Define a 1-D generator S’. Time-independent H.Time-independent H. Require new conjugate variables to be constants of motion.Require new conjugate variables to be constants of motion. Conjugate momentum is a constant J. Hamiltonian is constantHamiltonian is constant Conjugate position is cyclicConjugate position is cyclic Linear in timeLinear in time a frequency is a constant, ie from HJ units of action
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Periodic System A frequency suggests periodic motion. Assume q, p periodic.Assume q, p periodic. Period is Period is Evaluate the action and coordinate over one period. The change in w in one period is 1The change in w in one period is 1 J is the actionJ is the action w is the anglew is the angle
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Alternate Generators Generating functions differ by a Legendre transformation. The transformation can be expressed as type I. S is also periodic with period 1S is also periodic with period 1
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Simple Oscillator The oscillator H is constant and expressed in terms of p. The action can be integrated The generator can be defined from the action
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Derived Variables The angle can be derived from the generator. The momentum and position also can be derived.
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Physical View The motion in phase space is harmonic. Amplitudes of q, p Area in phase space is the times the action. Angle w repeats per cycle. p q J = E/ w = t
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Generating Function The generating function S’ can be found by integration and substitution. The function S comes from the Legendre transformationThe function S comes from the Legendre transformation
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Periodic Motion Libration is motion that is bounded in the angle. Rotation is motion covering all values of the angle. next q p q p
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