Definition of coupling constant in English:

coupling constant

Pronunciation /ˈkəp(ə)liNG ˈkänstənt/ /ˈkəp(ə)lɪŋ ˈkɑnstənt/


  • A measure of the strength of interaction between two particles, or between a particle and a field.

    ‘Newton's constant is the coupling constant for the gravitational force, for example.’
    • ‘For electromagnetism, the coupling constant is called the fine structure constant a and is formed by the electron charge, Planck's constant and the speed of light.’
    • ‘But its predictions for the coupling constants - the constants that describe the strengths of the strong, weak and electromagnetic interactions - were wrong.’
    • ‘That's an important detail, because the size of the gravitational coupling constant is what determines the distance scale of quantum gravity.’
    • ‘As I mentioned, the coupling constant of string theory is not really a constant at all, and in many respects it is very similar to the compactification moduli.’