IQI Weekly Seminar

Abstract: We study in detail the properties of the quantum East model, an interacting quantum spin chain inspired by simple kinetically constrained models of classical glasses.

Through a combination of analytics, exact diagonalization and tensor network methods we show the existence of a fast-to-slow transition throughout the spectrum that follows from a localization transition in the ground state.

On the slow side, we explicitly construct a large (exponential in size) number of non-thermal states which become exact finite-energy-density eigenstates in the large size limit,

as expected for a true phase transition.

A ``super-spin'' generalization allows us to find a further large class of area-law states proved to display very slow relaxation.

Under slow conditions, many eigenstates have a large overlap with product states and can be approximated well by matrix product states at arbitrary energy densities.

We discuss implications of our results for slow thermalization and non-ergodicity more generally for quantum East-type Hamiltonians and their extension in two or higher dimensions.