论文标题
确切的多体疤痕及其在约束量子链中的稳定性
Exact many-body scars and their stability in constrained quantum chains
论文作者
论文摘要
量子疤痕是非热特征状态的，其特征是低纠缠熵，最初在遭受最近邻里Rydberg封锁的系统中检测到，所谓的PXP模型。尽管这些特殊的特征状态大多数都忽略了分析描述，并且似乎与附近的大型系统的热特征状态杂交，但其中一些可以写成具有尺寸无关的键尺寸的矩阵乘积状态（MPS）。我们通过分析系统大小的忠诚度易感性的缩放来研究这些精确量子疤痕对扰动的响应。我们发现，其中一些在扰动理论的一级稳定，与本征态热化假设形成鲜明对比。但是，当考虑所有订单时，这种稳定性似乎都会崩溃。我们进一步研究了较大的阻断半径的模型，并找到了一组新型的精确量子疤痕，我们可以通过分析写下并与PXP精确特征态进行比较。我们表明，它们在一阶方面表现出对扰动的鲁棒性。
Quantum scars are non-thermal eigenstates characterized by low entanglement entropy, initially detected in systems subject to nearest-neighbor Rydberg blockade, the so called PXP model. While most of these special eigenstates elude an analytical description and seem to hybridize with nearby thermal eigenstates for large systems, some of them can be written as matrix product states (MPS) with size-independent bond dimension. We study the response of these exact quantum scars to perturbations by analysing the scaling of the fidelity susceptibility with system size. We find that some of them are anomalously stable at first order in perturbation theory, in sharp contrast to the eigenstate thermalization hypothesis. However, this stability seems to breakdown when all orders are taken into account. We further investigate models with larger blockade radius and find a novel set of exact quantum scars, that we write down analytically and compare with the PXP exact eigenstates. We show that they exhibit the same robustness against perturbations at first order.
