Non-ergodic one-magnon magnetization dynamics in flat-band frustrated antiferromagnets

The present view of modern physics on non-equilibrium dynamics is that generic quantum systems equilibrate or thermalize under rather general conditions, even closed systems under unitary time evolution. The investigation of exceptions thus not only appears attractive, in view of quantum computing where thermalization is a threat it also seems to be necessary. Here, we present aspects of the one-magnon dynamics on the sawtooth chain as well as on the kagome lattice antiferromagnet as an example of a non-equilibrating dynamics due to flat bands.

For both systems, localized eigenstates also called localized magnons lead to disorder-free localization and prevent the system from equilibration. This behavior is tunable by modifying the exchange interactions.