The Timescales of Quantum Breaking

Abstract

Due to the inevitable existence of quantum effects, a classical description generically breaks down after a finite quantum break‐time . We aim to find criteria for determining . To this end, we construct a new prototype model that features numerous dynamically accessible quantum modes. Using explicit numerical time evolution, we establish how depends on the parameters of the system such as its particle number N. The presence of a classical instability leads to or . In the stable case, we observe , although full quantum breaking may not take place at all. We find that the different regimes merge smoothly with (). As an outlook, we point out possibilities for transferring our results to black holes and expanding spacetimes.