Action-angle variables on regular invariant tori
Research context
postgraduate concept · conditional · As of 2026-10-10
For n integrable Hamiltonian degrees of freedom on a regular compact connected common level set of n independent commuting integrals, local canonical actions I_i and angles θ_i describe torus motion.
Key knowledge
For n integrable Hamiltonian degrees of freedom on a regular compact connected common level set of n independent commuting integrals, local canonical actions I_i and angles θ_i describe torus motion. With H=H(I), actions are constant and θ̇_i=∂H/∂I_i; global charts may fail at separatrices or singular fibres.
Values and equations
I_i=(1/(2π))∮_γ_i p·dq; İ_i=0; θ̇_i=∂H/∂I_i
- I_i
- Action of the chosen independent cycle J s
- θ_i
- Angle coordinate rad
- H
- Hamiltonian J
- γ_i
- Cycle on invariant torus
- p·dq
- Canonical action differential J s
Conditions and scope
- Smooth independent integrals and complete flows on the specified regular level set; angles have period 2π.
- I_i=(2π)⁻¹∮p·dq has units of action; the cycle basis must be specified. A local generating chart requires its relevant mixed Hessian to be invertible.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Inspected §§4.4–4.6: canonical charts, integrable systems, periodic actions and adiabatic conditions; source check dated 2026-10-10. Scope is limited to the cited statements, equations and assumptions, not the whole publication.
2026-10-10 · Author source inspection of the displayed claim, model assumptions and equations; independent exact-content and branch-inventory review is a separate gate. Contemporary status is a dated snapshot, not a promise of ongoing monitoring.
Entry details
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- research-physics-action-angle-tori
- Revision
- research.1
- Structured reference record
- Postgraduate & research reference