Scaling at the out-of-time-ordered correlator wavefront: Free versus chaotic models

Out-of-time-ordered correlators (OTOCs) are useful tools for investigating foundational questions such as thermalization in closed quantum systems because they can potentially distinguish between integrable and nonintegrable dynamics. Here, we discuss the properties of wavefronts of OTOCs by focusing on the region around the main wavefront at x=vBt, where vB is the butterfly velocity. Using a Heisenberg spin model as an example, we find that …