论文标题
用$ u（1）$对称性的受监视量子电路中的充电波动和电荷分解的纠缠
Charge fluctuation and charge-resolved entanglement in a monitored quantum circuit with $U(1)$ symmetry
论文作者
论文摘要
我们研究了一个（1+1） - 维量子电路，这些量子电路由HAAR随机统一门和投影测量值组成，可节省总$ U（1）$电荷，因此具有$ u（1）$对称性。除了测量诱导的体积法与区域律纠缠相之间的纠缠过渡外，我们还发现了两个阶段之间的相变，这些阶段以双分部分电荷波动随着子系统的大小或保持恒定而生长。在这种电荷 - 拖延过渡时，通过与tomonaga-luttinger-luttinger-liquid理论相似的临界尺度行为获得的初始状态获得的稳态数量，用于与$ u（1）$对称性的平衡临界量子系统，例如，相互仪的对数尺度，电荷范围的范围范围范围的范围范围范围的范围范围范围，以下范围。纠缠其系数成为通用参数中的通用二次函数。但是，这些关键特征与基于副本场理论的最新预测并映射到经典的统计机械模型相比，这些关键特征并不持续到过渡以下。
We study a (1+1)-dimensional quantum circuit consisting of Haar-random unitary gates and projective measurements that conserve a total $U(1)$ charge and thus have $U(1)$ symmetry. In addition to a measurement-induced entanglement transition between a volume-law and an area-law entangled phase, we find a phase transition between two phases characterized by bipartite charge fluctuation growing with the subsystem size or staying constant. At this charge-fluctuation transition, steady-state quantities obtained by evolving an initial state with a definitive total charge exhibit critical scaling behaviors akin to Tomonaga-Luttinger-liquid theory for equilibrium critical quantum systems with $U(1)$ symmetry, such as logarithmic scaling of bipartite charge fluctuation, power-law decay of charge correlation functions, and logarithmic scaling of charge-resolved entanglement whose coefficient becomes a universal quadratic function in a flux parameter. These critical features, however, do not persist below the transition in contrast to a recent prediction based on replica field theory and mapping to a classical statistical mechanical model.
