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The Field Ocean: the maths

The Klein–Gordon equation (a relativistic field) on a lattice of points, integrated step by step. The lower field has mass m; the upper is massless. Computed live.

Equations

∂²φ/∂t² = ∂²φ/∂x² − m²φ
The field equation: waves on a field whose 'mass' resists being moved.
ω² = 4 sin²(k/2) + m²
How fast a ripple of wavenumber k oscillates on the lattice (in the continuum, ω² = k² + m²).
vgroup = dω/dk = sin k / ω
How fast the ripple travels. For m = 0 it's the speed of light (almost exactly, at this k); for m > 0 it's slower.

Constants

k0.25 per lattice stepthe travelling ripple's wavenumber
c1 lattice step per time stepunits

Worked examples ✓ checked on every change

Massive ripple's speed as a share of light's, m = 0.3656.9%v = sin k / ω, both fields
…with no mass100%a massless ripple travels at light speed

The app's test suite puts the lab in each setup, reads the lab's own result, and fails if it strays from these values.

What's simplified

  • One space dimension; a classical field (no quantum particles), which is how the wave side of a particle behaves.
  • Mass is a slider: in nature it comes from the Higgs field, fixed for each particle.

Where it breaks

At lattice-scale wavelengths (k near π), where the grid shows; the travelling ripple is kept well above that.

Sources: O. Klein (1926); W. Gordon (1926); any quantum-field-theory text (e.g. Peskin & Schroeder, 1995, ch. 2).

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