The Timescales of Quantum Breaking

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