Asymptotic Analysis of the Wigner $3j$-Symbol in the Bargmann Representation

Abstract

We derive the leading asymptotic limit of the Wigner $3j$-symbol from a stationary phase approximation of a twelve dimensional integral, obtained from an inner product between two exact Bargmann wavefunctions. We show that, by the construction of the Bargmann inner product, the stationary phase conditions have a geometric description in terms of the Hopf fibration of ${\mathbb{C}}^6$ into ${\mathbb{R}}^3\times {\mathbb{R}}^3\times {\mathbb{R}}^3$. In addition, we find that, except for the usual modification of the quantum numbers by 1/2, the imaginary part of the logarithm of a Bargmann wavefunction, evaluated at the stationary points, is equal to the asymptotic phase of the $3j$-symbol.

23 pages, 2 figures