Robust quantum many-body scars in the one-dimensional spin-1 Kitaev model

Abstract: Experimental observation of coherent oscillations in a Rydberg atom chain [Bernien et al., Nature 551, 579 (2017)] has led to the discovery of quantum many-body scars (QMBS) which is a new paradigm for ergodicity-breaking. The experimental findings in the Rydberg chain can be well captured by a kinetically constrained model called the "PXP" model, which has been shown to host the Eigenstate Thermalization Hypothesis (ETH)-violating scar states in the middle of the spectrum. Much effort has been put into identifying similar kinetically restricted systems that show a violation of ETH. In this work, we study the QMBS that can arise in one such model, namely the spin-$1$ Kitaev chain, where owing to some conserved quantities, the Hilbert space gets fragmented into unequal disconnected subspaces. Recently, You et al. [Phys. Rev. Research 4, 013103 (2022)] showed that the ground state sector of this chain can be mapped exactly onto the prototypical PXP model and thus hosts QMBSs. Here, we demonstrate that the phenomenon of scarring is also present in other sectors, and in particular, we identify a sector that exhibits substantially more scarring than the ground state one. We propose an initial state and numerically demonstrate that its fidelity revivals are robust and longer-lived than those in the PXP model.