标题： 时间顺序外关联函数和冷原子中信息杂乱的检测：阶梯XX模型 显示英文标题

标题： Detection of out-of-time-order correlators and information scrambling in cold atoms: Ladder-XX model

摘要： 量子混沌最近成为讨论的焦点，非时间顺序关联函数（OTOC）是理解量子多体系统不同相位中信息杂乱的一种工具。我们提出了一种无序梯子自旋模型，即XX梯子，该模型可以在可扩展的冷原子装置中设计，以使用一种新颖的符号反转协议来检测时间反向演化的OTOC。我们研究了XX梯子的清洁和无序极限，根据OTOC的衰减特性对模型的不同相位（热-MBL）进行表征，并指出稀有区域效应。出现的有效光锥表现出次线性行为，而蝴蝶锥则与光锥显著不同，表现出超线性行为。基于我们的结果，可以观察到在从研究充分的一维自旋模型到局部设置中未探索的二维自旋模型的转变过程中，信息杂乱如何发生变化。 显示英文摘要

摘要： Out-of-time-order correlators (OTOC), recently being the center of discussion on quantum chaos, are a tool to understand the information scrambling in different phases of quantum many-body systems. We propose a disordered ladder spin model, XX-ladder, which can be designed in a scalable cold atom setup to detect OTOC with a novel sign reversal protocol for the evolution backward in time. We study both the clean and disordered limits of XX-ladder, characterize different phases (thermal-MBL) of the model based on the decay properties of OTOCs and point to rare-region effects. Emergent effective lightcone shows sublinear behaviour, while the butterfly cones drastically differ from the lightcone via demonstrating superlinear behaviour. Based on our results, one can observe how the information scrambling changes in the transition from well-studied 1D spin models to unexplored 2D spin models in a local setting.