Condensed Matter Theory Center and Joint Quantum Institute, Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
Phys Rev Lett. 2019 Oct 4;123(14):147201. doi: 10.1103/PhysRevLett.123.147201.
We study the spin-1 XY model on a hypercubic lattice in d dimensions and show that this well-known nonintegrable model hosts an extensive set of anomalous finite-energy-density eigenstates with remarkable properties. Namely, they exhibit subextensive entanglement entropy and spatiotemporal long-range order, both believed to be impossible in typical highly excited eigenstates of nonintegrable quantum many-body systems. While generic initial states are expected to thermalize, we show analytically that the eigenstates we construct lead to weak ergodicity breaking in the form of persistent oscillations of local observables following certain quantum quenches-in other words, these eigenstates provide an archetypal example of so-called quantum many-body scars. This Letter opens the door to the analytical study of the microscopic origin, dynamical signatures, and stability of such phenomena.
我们研究了 d 维超立方格上的自旋-1 XY 模型，表明这个广为人知的非可积模型拥有广泛的异常有限能密度本征态，具有显著的特性。具体而言，它们表现出亚扩展性的纠缠熵和时空长程有序，这两者都被认为是典型的非积量子多体系统中高度激发的本征态所不可能具有的。虽然一般的初始态预计会热化，但我们分析表明，我们构造的本征态会导致局部可观测量的持续振荡，从而出现弱遍历破坏——换句话说，这些本征态提供了所谓量子多体疤痕的典型范例。这封信为分析研究这些现象的微观起源、动力学特征和稳定性开辟了道路。
