fine-structure constant
Sign in to saveAlso known as fine structure constant, Sommerfeld's constant, Sommerfeld fine structure constant
physical constant quantifying the strength of the electromagnetic interaction between elementary charged particles
~25 min read
Encyclopedic overview
In physics, the fine-structure constant, also known as the Sommerfeld constant, commonly denoted by α (the Greek letter alpha), is a fundamental physical constant that quantifies the strength of the electromagnetic interaction between elementary charged particles.
It is a dimensionless quantity (dimensionless physical constant), independent of the system of units used, which is related to the strength of the coupling of an elementary charge e with the electromagnetic field, by the formula
Excerpted from Wikipedia’s “fine-structure constant” article, available under the CC BY-SA 4.0 licence.