Equations · equation
Fine-Structure Constant
Quantum Field Theory · 1916
- Equation
- α = e²/(4πε₀ℏc) ≈ 1/137
- Field
- Quantum Field Theory
- Named After
- Arnold Sommerfeld
- Year
- 1916
Symbols
e electron charge · ε₀ permittivity of free space · ℏ reduced Planck constant · c speed of light · dimensionless — the same number for any choice of units
Significance
The strength of electromagnetism distilled to one pure number, about 1/137 — small enough that atoms are stable and QED can be computed as a series of corrections. Why 137? Nobody knows; Feynman called it 'one of the greatest damn mysteries of physics'.
Referenced by
constant
element
equation
event
theory
Open on the Equations shelf — the interactive card, the filters, and everything alongside it.