Many-body chaos at weak coupling

The strength of chaos in large $N$ quantum systems can be quantified using ${\lambda }_L$, the rate of growth of certain out-of-time-order four point functions. We calculate ${\lambda }_L$ to leading order in a weakly coupled matrix ${\mathrm{\Phi }}^4$ theory by numerically diagonalizing a ladder kernel. The computation reduces to an essentially classical problem.