How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
An oblique plane wave with a nonzero longitudinal electric component
Exact plane-wave example in the smooth, source-free vacuum Maxwell model and the propagating cone of the ideal angular-spectrum model. It illustrates the longitudinal component required by Maxwell's equations for its specified transverse polarization; it asserts no measured field, focal apparatus, or torque.
Example
Let , , , and choose a real in . Put The real fields and are an exact, forward, source-free vacuum plane-wave mode. In particular, Thus setting while keeping this transverse amplitude would not give an exact Maxwell mode.
Example references
Facts & Assumptions
Given: A fixed SI laboratory chart, , , , , , and real in .
The SI chart has spatial coordinates in metres and time in seconds, , and and have units and tesla. The electric and magnetic fields as fixed-time spatial vector fields Laboratory geometry: a restricted inertial chart, its spatial slices and fixed-time fields Framework-local SI units, the vacuum constants and the exact/measured status of their values Forward angular-spectrum beam
The plane-wave convention uses the real part of complex amplitudes times . Complex plane-wave fields: real parts of complex exponentials
The adopted smooth source-free vacuum Maxwell equations, with and , are , , and ; and are the charge and current densities of the source definition, and divergence and curl are the coordinate operators of the fixed spatial chart. The microscopic vacuum Maxwell equations: smooth and weak branches Charge parameter, frame charge and current densities, volume charge and flux, and the four-current Divergence and curl of a vector field
The complex exponential satisfies and the chain rule; real parts commute with these real partial derivatives. The plane-wave fields are therefore . Use the Euclidean dot and cross products on the spatial vectors. Complex plane-wave fields: real parts of complex exponentials The complex exponential is entire and its complex derivative is itself The chain rule for total derivatives: Directional derivatives and partial derivatives of a map The Euclidean inner product on The cross product in
For an exact mode with these , the longitudinal relation and cone bound are as stated in the paraxial error theorem. Paraxial phase and longitudinal-field bounds
Verification
Since , is positive. The definitions give , , and . Thus is a forward wavevector of length , and is transverse to it.
By [F3], for each spatial coordinate , componentwise, and ; the same formulas hold with in place of . From [step 1.1], and where the last equality uses . Summing the spatial derivatives therefore yields Thus all four source-free Maxwell equations in [A1] hold pointwise, so these real fields are an exact mode.
The constructed transverse amplitude is . Applying [F4] gives and . Since , , and , . Hence the alternative with this same transverse amplitude is incompatible with source-free Maxwell transversality.
Remarks
For the illustrative case and , the normalized x-z projections are and ; their dot product is zero. The arrows use these separate dimensionless normalizations, and the figure is schematic only. The Maxwell verification is the component proof in step 2.1, not the drawing.
\begin{tikzpicture}[x=2.5cm,y=2cm,>=stealth]
\draw[->] (-0.12,0) -- (1.25,0) node[right] {$x$ component};
\draw[->] (0,-0.8) -- (0,1.15) node[above] {$z$ component};
\draw[dashed,gray] (0,0) -- (0.5,0);
\draw[dashed,gray] (0.5,0) -- (0.5,{sqrt(3)/2});
\draw[very thick,->] (0,0) -- (0.5,{sqrt(3)/2})
node[above right] {$\mathbf K/k_0$};
\draw[very thick,->,blue] (0,0) -- (1,{-1/sqrt(3)})
node[below right] {$\mathbf e/E_0$};
\node[below] at (0.5,0) {$\kappa/k_0=1/2$};
\node[right] at (0.5,0.53) {$k_z/k_0=\sqrt3/2$};
\end{tikzpicture}
Depends on
The cross product in
Directional derivatives and partial derivatives of a map
Divergence and curl of a vector field
The Euclidean inner product on
The electric and magnetic fields as fixed-time spatial vector fields
Laboratory geometry: a restricted inertial chart, its spatial slices and fixed-time fields
Charge parameter, frame charge and current densities, volume charge and flux, and the four-current
Framework-local SI units, the vacuum constants and the exact/measured status of their values
Complex plane-wave fields: real parts of complex exponentials
Forward angular-spectrum beam
The microscopic vacuum Maxwell equations: smooth and weak branches
Paraxial phase and longitudinal-field bounds
The chain rule for total derivatives:
The complex exponential is entire and its complex derivative is itself