Emergent symmetries and slow quantum dynamics in a Rydberg-atom chain with confinement
Emergent symmetries and slow quantum dynamics in a Rydberg-atom chain with confinement
复制标题
DOI：
10.1103/physrevb.103.214304
复制
发表时间：
2021-03
影响因子：
3.7
通讯作者：
I. Chen;Thomas Iadecola
中科院分区：
文献类型：
--
作者：
I. Chen;Thomas Iadecola
光镊阵列中的里德伯原子为非平衡量子多体物理提供了一个平台。PXP模型描述了这种系统在强相互作用的里德伯封锁制度的动力学，并显着表现出弱非遍历动力学由于量子多体疤痕。在这里，我们研究的PXP模型在一个强交错外场，这已被提出来体现准粒子禁闭在光的映射到格点规范理论。我们使用数值精确对角化和微扰理论的强场极限附近的限制制度的特点。除了预期的紧急产生的交错场的对称性，我们发现了第二个紧急的对称性，是特殊的PXP模型。这些涌现的对称性和里德伯封锁约束之间的相互作用大大减缓了系统的动力学，超出了天真的预期。我们设计了一个嵌套的Schriffl-Wolff微扰理论，以正确地解释新出现的对称性，并表明这种治疗是必不可少的，以了解数值观察到的弛豫时间尺度。我们还讨论了与希尔伯特空间分裂的联系，并将新涌现对称性的起源追溯到在多体疤痕背景下发现的“近SU（2）”代数。
Rydberg atoms in optical tweezer arrays provide a playground for nonequilibrium quantum manybody physics. The PXP model describes the dynamics of such systems in the strongly interacting Rydberg blockade regime and notably exhibits weakly nonergodic dynamics due to quantum manybody scars. Here, we study the PXP model in a strong staggered external field, which has been proposed to manifest quasiparticle confinement in light of a mapping to a lattice gauge theory. We characterize this confining regime using both numerical exact diagonalization and perturbation theory around the strong-field limit. In addition to the expected emergent symmetry generated by the staggered field, we find a second emergent symmetry that is special to the PXP model. The interplay between these emergent symmetries and the Rydberg blockade constraint dramatically slows down the system’s dynamics beyond naive expectations. We devise a nested Schrieffer-Wolff perturbation theory to properly account for the new emergent symmetry and show that this treatment is essential to understand the numerically observed relaxation time scales. We also discuss connections to Hilbert space fragmentation and trace the origin of the new emergent symmetry to a “nearly-SU(2)” algebra discovered in the context of many-body scarring.