Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
Phys Rev E. 2022 Dec;106(6-1):064210. doi: 10.1103/PhysRevE.106.064210.
The entanglement between two weakly coupled bosonic Josephson junctions is studied in relation to the classical mixed phasespace structure of the system, containing symmetry-related regular islands separated by chaos. The symmetry-resolved entanglement spectrum and bipartite entanglement entropy of the system's energy eigenstates are calculated and compared to their expected structure for random states that exhibit complete or partial ergodicity. The entanglement spectra of chaos-supported eigenstates match the microcanonical structure of a Generalized Gibbs Ensemble due to the existence of an adiabatic invariant that restricts ergodization on the energy shell. The symmetry-resolved entanglement entropy of these quasistochastic states consists of a mean-field maximum entanglement term and a fluctuation correction due to the finite size of the constituent subsystems. The total bipartite entanglement entropy of the eigenstates correlates with their chaoticity. Island-supported eigenstates are macroscopic Schrödinger cat states for particles and excitations with substantially lower entanglement.
研究了两个弱耦合玻色约瑟夫森结之间的纠缠，与系统的经典混合相空间结构有关，其中包含由混沌隔开的具有对称性相关的规则岛。计算了系统能量本征态的对称分辨纠缠谱和双体纠缠熵，并将其与表现出完全或部分遍历性的随机态的预期结构进行了比较。由于存在绝热不变量限制了能量壳层上的遍历，因此支持混沌的本征态的纠缠谱与广义吉布斯系综的微正则结构相匹配。这些准随机态的对称分辨纠缠熵由平均场最大纠缠项和由于组成子系统的有限大小引起的涨落修正组成。本征态的总双体纠缠熵与它们的混沌程度相关。岛支持的本征态是粒子和激发子的宏观薛定谔猫态，其纠缠度要低得多。
