Quantum many-body scars in a Landau level on a thin torus
Sanjay Moudgalya, B. Andrei Bernevig, Nicolas Regnault
Abstract
We study a kinetically constrained pair-hopping model that arises within a Landau level in the quantum Hall effect. At filling $\ensuremath{\nu}=1/3$, the model exactly maps onto the so-called ``PXP model,'' a constrained model for the Rydberg atom chain that is numerically known to exhibit ETH-violating states in the middle of the spectrum or quantum many-body scars. Indeed, particular charge density wave configurations exhibit the same revivals seen in the PXP model. We generalize the mapping to fillings factors $\ensuremath{\nu}=p/(2p+1)$, and show that the model is equivalent to nonintegrable spin chains within particular constrained Krylov Hilbert spaces. These lead to new examples of quantum many-body scars which manifest as revivals and slow thermalization of particular charge density wave states. Finally, we investigate the stability of the quantum scars under certain Hamiltonian perturbations motivated by the fractional quantum Hall physics.