Quantum many-body scars in Floquet magnetic systems

Recent experimental and theoretical works have found athermal behavior for quench dynamics of specially prepared initial states in an otherwise nonintegrable clean system in one dimension. These have been dubbed as quantum many-body scars (QMBS). Building on our previous work [K.Lee et al., Phys. Rev. B 101, 241111(R) (2020)] which demonstrated the presence of QMBS with perfect revivals in high dimensional magnetic systems in a magnetic field, we explore the question of their stability under Floquet driving. We study the periodically driven bond-alternating spin-1/2 nearest neighbor XXZ Hamiltonian and its two-dimensional equivalent on the highly frustrated kagome lattice. These models harbor a manifold of zero modes which remain stable to certain driving protocols. We characterise the non-equilibrium dynamics and the enhanced coherence of a class of initial states. Our models and the corresponding findings for these nonequilibrium relaxation effects are potentially realizable on current ion trap setups, and we also discuss the feasibility of observing them in real materials.