In the earlier work we identified the quantum scars as a mechanism of weak ergodicity breaking in interacting many-body systems. The name “quantum many-body scars” was inspired by the presence of unstable TDVP trajectory reported in Ref. [Phys. Rev. Lett. 122, 040603 (2019)], thus allowing to make parallels with quantum scars in single-particle billiards.
However, in a few-body quantum systems quantum scarring is not the only possible mechanism of dependence of relaxation on initial state. In fact, the mixed phase space in a few body systems presents another common mechanism. In the most recent work arXiv:1905.08564 we generalized the concept of mixed phase space to strongly interacting quantum systems.