All of statistical physics is based upon a simple and familiar principle: physical systems equilibrate. Until recently, this principle was believed to be a generic feature of interacting many-particle systems; the discovery of many-body localization, a phase of matter that avoids equilibration, has sparked renewed interest into the foundations of statistical mechanics. Subsequent investigation uncovered myriad phenomena, ranging from prethermalization and many-body scars to fractons and Stark localization, where equilibration can be avoided to varying degrees through different mechanisms. However, to date, we still lack a general framework to sharply differentiate between distinct forms of quantum dynamics.
- What are the universal features that help us categorize these different dynamics into different classes of behavior?
- What other dynamical phenomena are out there for us to find?