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Coupling constant
The coupling constant α determines the strength of the electromagnetic interaction. The value is
Explanation
This fundamental physical constant is dimensionless and has the same value in all units systems
where
e Elementary charge ℏ Reduced Planck constant c Speed of light ε0 Vacuum permittivity
HistoryThe constant was introduced by the German physicist Arnold Sommerfeld in 1916 and is therefore sometimes named the Sommerfeld constant. Most commenly it is called the fine-structure constant. |