Compton Wavelength

The electron's quantum length scale h/mₑc, governing the wavelength shift of scattered photons.

Specifications & Metrics

symbol

λ_C

status

Measured (CODATA 2022)

value

2.42631023538 × 10⁻¹² ± 7.6 × 10⁻²² m

Relative Scale in Constants

Core Principles & Analysis

• Equals h/mₑc = 2.43 picometres, the shift scale Compton measured in X-ray scattering in 1923.
• Compton scattering's wavelength shift proved that photons carry momentum like particles.
• Confining an electron below λ_C costs enough energy to create electron-positron pairs — the threshold where quantum field theory becomes unavoidable.

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