Nonthermal States Arising from Confinement in One and Two Dimensions
Nonthermal States Arising from Confinement in One and Two Dimensions
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DOI：
10.1103/physrevlett.122.130603
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发表时间：
2019-04-05
影响因子：
8.6
通讯作者：
Robinson, Neil J.
中科院分区：
文献类型：
--
作者：
James, Andrew J. A.;Konik, Robert M.;Robinson, Neil J.
结果表明，在连续和晶格理论中，量子伊辛模型中的限制导致了一维(1D)和二维(2D)的非热本征态。在有序相中，禁闭纵场的存在导致激发谱的深刻重组，低能两粒子连续体被离散的“介子”模(线性约束的磁区壁对)所取代。这些模存在于光谱中很远的地方，并且是非典型的，因为在能量为E的状态下的期望值与微正则(热)系综预测不一致。由于令人惊讶地缺乏与(n&>=4)域壁连续体的杂交，单介子态持续存在于双介子阈值之上，这一结果存活到热力学极限，这可以从分析计算中得到理解。这些态的存在被揭示在反常的后猝灭动力学中，例如缺少光锥，抑制纠缠熵的增长，以及一些初始态没有热化。非热态被限制在有序相中--无序(顺磁)相在没有可积性的情况下在一维和二维中都表现出典型的热化模式。
We show that confinement in the quantum Ising model leads to nonthermal eigenstates, in both continuum and lattice theories, in both one (1D) and two dimensions (2D). In the ordered phase, the presence of a confining longitudinal field leads to a profound restructuring of the excitation spectrum, with the low-energy two-particle continuum being replaced by discrete "meson" modes (linearly confined pairs of domain walls). These modes exist far into the spectrum and are atypical, in the sense that expectation values in the state with energy E do not agree with the microcanonical (thermal) ensemble prediction. Single meson states persist above the two-meson threshold due to a surprising lack of hybridization with the (n >= 4)-domain wall continuum, a result that survives into the thermodynamic limit and that can be understood from analytical calculations. The presence of such states is revealed in anomalous postquench dynamics, such as the lack of a light cone, the suppression of the growth of entanglement entropy, and the absence of thermalization for some initial states. The nonthermal states are confined to the ordered phase-the disordered (paramagnetic) phase exhibits typical thermalization patterns in both 1D and 2D in the absence of integrability.