2018/10/31 by Cheng-Ju Lin, Olexei I. Motrunich · 3 citations
Physics and Astronomy · #cond-mat.quant-gas #cond-mat.stat-mech
paper · pdf · doi:10.1103/physrevlett.122.173401
published as Phys. Rev. Lett. 122, 173401 (2019) · Published version. In addition to (v2): (1) Add additional proofs to the exact scar states and intuitions behind SMA and MMA to the appendices. (2) Add entanglement scaling of SMA and MMA to the appendices
arxiv created 2019/05/06 · arxiv updated 2019/05/07
A recent experiment in the Rydberg atom chain observed unusual oscillatory quench dynamics with a charge density wave initial state, and theoretical works identified a set of many-body "scar states" showing nonthermal behavior in the Hamiltonian as potentially responsible for the atypical dynamics. In the same nonintegrable Hamiltonian, we discover several eigenstates at infinite temperature that can be represented exactly as matrix product states with finite bond dimension, for both periodic boundary conditions (two exact E = 0 states) and open boundary conditions (two E = 0 states and one each E = ± √(2)). This discovery explicitly demonstrates violation of strong eigenstate thermalization hypothesis in this model and uncovers exact quantum many-body scar states. These states show signatures of translational symmetry breaking with period-2 bond-centered pattern, despite being in one dimension at infinite temperature. We show that the nearby many-body scar states can be well approximated as "quasiparticle excitations" on top of our exact E = 0 scar states, and propose a quasiparticle explanation of the strong oscillations observed in experiments.