Complexity, action, and black holes

Our earlier paper “Complexity Equals Action” conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the “Wheeler-DeWitt” patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.Hertz FoundationUnited States. Dept. of Energy (Cooperative Research Agreement Contract DE-SC00012567