Resonance and persistence of invariant tori
Research context
postgraduate concept · conditional · As of 2026-10-10
For H=H₀(I)+εH₁(I,θ), an integer resonance k·ω(I)=0 makes that Fourier mode unsuitable for ordinary nonresonant elimination.
Key knowledge
For H=H₀(I)+εH₁(I,θ), an integer resonance k·ω(I)=0 makes that Fourier mode unsuitable for ordinary nonresonant elimination. KAM persistence applies to sufficiently small, sufficiently smooth near-integrable perturbations with nondegenerate frequency maps and suitable Diophantine frequencies; it does not protect every orbit or a separatrix.
Values and equations
k·ω=0; |k·ω|≥γ|k|^(−τ) for k∈ℤⁿ∖{0}
- k
- Integer resonance vector
- ω,γ
- Angular frequencies and Diophantine frequency bound s⁻¹
- τ
- Diophantine exponent
Conditions and scope
- Finite-dimensional conservative Hamiltonian model; ε is dimensionless after fixing an energy scale.
- The Diophantine constants, regularity, nondegeneracy and size threshold are theorem-dependent. Resonant normal forms retain slow combinations rather than divide by zero.
Sources · 2
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. Inspected §§1.2, 2, 4–6: splitting, symplecticity, modified Hamiltonians, non-resonance and constraint algorithms; 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-resonance-kam
- Revision
- research.1
- Structured reference record
- Postgraduate & research reference