Branching Time in SYK-like Models

The branching time in SYK-like models is defined as the average time separation of rungs when computing the out-of-time-order correlator. We argue that a parametrically large branching time is necessary to obtain holographic models with non-trivial bulk dynamics. In this work, we establish a bound on the branching time for SYK-like models. Thus, such models are unlikely candidates for sub-AdS holography. We also derive a relation between the branching time, the Lyapunov exponent, and the quasiparticle lifetime in the weak coupling limit.