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The 42 pages that link to Perturbation theory, each with the reason it gives.

• Taylor seriesRelated: Many perturbation methods organize corrections as power series in a small parameter.

• Orbital mechanicsRelated: It estimates how nonspherical gravity, drag, and other forces change ideal trajectories.

• Richard FeynmanRelated: His diagrams organize the successive terms used in perturbative quantum electrodynamics.

• Feynman diagramRelated: Diagrams organize successive terms in expansions in interaction strength.

• Asymptotic analysisRelated: Asymptotic expansions often supply approximations when exact solutions are unavailable.

• Condition numberNarrower topic: Condition numbers summarize the sensitivity that perturbation analysis investigates.

• Effective field theoryRelated: Many effective theories predict observables through ordered perturbative expansions.

• Path integral formulationRelated: It turns path-integral expressions into systematic approximations for interacting systems.

• Fine-structure constantRelated: Small powers of the constant make many electromagnetic calculations tractable.

• Jordan normal formRelated: Small perturbations can radically change Jordan block structure, limiting numerical usefulness.

• Frontier molecular orbital theoryNarrower topic: Orbital interaction arguments often interpret bonding changes as perturbations between reactant orbitals.

• Gravitational perturbationRelated: Orbital calculations often treat secondary gravitational forces as corrections to a dominant attraction.

• Theoretical physicsRelated: It makes predictions possible when exact solutions to a model are unavailable.

• Lattice gauge theoryCompared with: Lattice methods can address strongly coupled regimes where perturbative expansions fail.

• Separation of variablesCompared with: Perturbation methods address problems that resist exact separated solutions or include weak complications.

• Fritz LondonRelated: London’s treatment of weak intermolecular attraction relies on quantum perturbation methods.

• Action-angle variablesRelated: Action-angle variables organize small departures from integrable motion.

• AnharmonicityRelated: It estimates frequency and energy corrections when anharmonic terms are weak.

• Padé approximantRelated: Rational approximants can improve predictions from finite perturbative expansions.

• WKB approximationCompared with: Ordinary perturbation theory expands around a reference solution; WKB instead tracks a varying local phase.

• Fermi's golden ruleNarrower topic: The golden rule is a rate-level approximation built from perturbative transition amplitudes.

• Lunar theoryRelated: Lunar calculations treat solar and planetary effects as corrections to idealized orbital motion.

• Astronomical tablesRelated: Perturbation terms let tables account for gravitational influences beyond an ideal two-body orbit.

• Urbain Le VerrierRelated: Le Verrier treated Uranus’s deviations as small effects of an unknown gravitational influence.

• Feynman rulesRelated: The rules organize amplitudes as sums ordered by interaction strength.

• Virtual particleNarrower topic: Virtual particles arise within its expansion of quantum-field interactions.

• Kolmogorov–Arnold–Moser theoremRelated: KAM gives a rigorous account of what ordinary perturbative expansions alone may not establish.

• Linear response theoryRelated: A weak disturbance permits expansion to first order in its strength.

• Orbit of the MoonRelated: It separates the Moon’s dominant Earth-bound motion from smaller solar effects.

• Yang–Mills existence and mass gapCompared with: Perturbative expansions do not establish nonperturbative existence or a positive spectral gap.

• John Hasbrouck Van VleckRelated: His calculations treated magnetic fields and crystal environments as perturbations to atomic states.

• Kepler orbitRelated: It describes corrections to Keplerian motion from other bodies and weak forces.

• Simon NewcombRelated: Newcomb used perturbative calculations to account for planets disturbing one another’s orbits.

• Johann Gottfried GalleRelated: Gravitational perturbations of Uranus were the clues used to predict Neptune.

• Brook TaylorRelated: Its expansions apply Taylor’s local approximation principle to changing parameters.

• Field and string theory models and techniquesRelated: Many practical predictions begin as expansions around a free or weakly coupled theory.

• Flow instabilityRelated: Stability calculations treat disturbances as perturbations to an established flow.

• Furry's theoremRelated: The theorem removes whole classes of terms from the QED expansion.

• Many-body techniquesRelated: It estimates interaction effects order by order when a suitable reference system exists.

• Mathematical formulation of the Standard ModelRelated: Many Standard Model predictions use expansions in interaction strengths.

• Mathematical methods in physicsRelated: It estimates how small corrections alter an idealized physical model.

• Series expansionRelated: Its approximations are organized as series in the perturbation strength.