Task: Text Categorization
Input (English): The most precise measurement for this quantity has come from the magnetic moment of the electron. For an electromagnetic interaction with n vertices, the amplitude for the interaction is proportional to this constant to the nth power. The square of this number is the ratio of the Hartree energy to the rest mass of the electron, and it is the ratio of the classical velocity in the ground state of the Hydrogen atom to the speed of light. The probability of a mechanism of an electromagnetic interaction involving n virtual photons is proportional to this constant to the 2n power, which in Quantum Electrodynamics indicates that this is the coupling constant for electromagnetic interactions. For 10 points, name this dimensionless constant in quantum mechanics, famously miscalculated by a numerological argument by Eddington, which is approximately one over 137.
Output (English): Science