标题： 使用费米-哈伯德量子模拟器探究赝隙的磁性起源 显示英文标题

标题： Probing the magnetic origin of the pseudogap using a Fermi-Hubbard quantum simulator

摘要： 在强关联材料中，相互作用的电子是纠缠的，并形成集体量子态，导致丰富的低温相图。 显著的例子包括铜氧化物超导体，在临界温度以上，超导性在一种不寻常的“赝隙”金属态中于低掺杂下出现。 费米-哈伯德模型描述了与强电子关联相关的广泛现象，尽管其表述简单，但仍存在主要的计算挑战。 在此背景下，超冷原子量子模拟器为关联量子态的微观性质提供了无价的见解。 在这里，我们使用一个量子气体显微镜费米-哈伯德模拟器，在已知会发展出赝隙的区域中探索广泛的掺杂水平和温度。 通过测量高达五阶的多点关联函数，我们发现磁性和高阶自旋-电荷关联中的新普遍行为。 这种行为的特点是一个与掺杂有关的能量尺度，该尺度控制着冷却时磁性关联长度的指数增长。 与行列式量子蒙特卡洛和最小纠缠典型热态模拟的准确比较证实，这个能量尺度与赝隙温度$T^{*}$相符。 我们的研究结果建立了对赝隙磁性起源和物理本质的定性和定量理解，并为探索预期在更低温度下出现的载流子配对和集体现象铺平了道路。 显示英文摘要

摘要： In strongly correlated materials, interacting electrons are entangled and form collective quantum states, resulting in rich low-temperature phase diagrams. Notable examples include cuprate superconductors, in which superconductivity emerges at low doping out of an unusual ``pseudogap'' metallic state above the critical temperature. The Fermi-Hubbard model, describing a wide range of phenomena associated with strong electron correlations, still offers major computational challenges despite its simple formulation. In this context, ultracold atoms quantum simulators have provided invaluable insights into the microscopic nature of correlated quantum states. Here, we use a quantum gas microscope Fermi-Hubbard simulator to explore a wide range of doping levels and temperatures in a regime where a pseudogap is known to develop. By measuring multi-point correlation functions up to fifth order, we uncover a novel universal behaviour in magnetic and higher-order spin-charge correlations. This behaviour is characterized by a doping-dependent energy scale that governs the exponential growth of the magnetic correlation length upon cooling. Accurate comparisons with determinant Quantum Monte Carlo and Minimally Entangled Typical Thermal States simulations confirm that this energy scale agrees well with the pseudogap temperature $T^{*}$. Our findings establish a qualitative and quantitative understanding of the magnetic origin and physical nature of the pseudogap and pave the way towards the exploration of pairing and collective phenomena among charge carriers expected to emerge at lower temperatures.