  Previous studies show that, in quantum chaotic and integrable systems, the
so-called out-of-time-ordered correlator (OTOC) generically behaves differently
at long times, while, it may show similar early growth in one-body systems. In
this paper, by means of numerical simulations, it is shown that OTOC has
similar early growth in two quantum many-body systems, one integrable and one
chaotic.
