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roaming文件夹是干嘛的 roaming文件夹

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roaming文件夹是干嘛的 roaming文件夹


编译｜冯维维
Science, 26 NOVEMBER 2021, VOL 374, ISSUE 6571
《科学》2021年11月26日 ， 第374卷 ， 6571期
物理学Physics
Direct visualization of magnetic domains and moiré magnetism in twisted 2D magnets
在扭曲的二维磁体中磁畴和moiré磁性的直接可视化
▲ 作者：TIANCHENG SONG, QI-CHAO SUN, ERIC ANDERSON, CHONG WANGJIMIN QIANTAKASHI TANIGUCHI, KENJI WATANABE, MICHAEL A. MCGUIR, RAINER ST?HR, XIAODONG XU
▲ 链接：
https://www.science.org/doi/10.1126/science.abj7478
▲ 摘要
【roaming文件夹是干嘛的 roaming文件夹】石墨烯的单分子扭转层导致了许多不寻常的相关状态 。这种方法激发了研究人员尝试扭转二维磁铁 ， 但这种实验被证明是一个艰巨的挑战 。
作者用小扭曲角的二维磁铁三碘化铬层制作了结构 。利用金刚石中的氮空位中心作为磁强计 ， 对扭曲单层结构和扭曲三层结构的磁畴进行了成像 。发现了扭曲三层薄膜的铁磁和反铁磁畴的周期性模式 。
▲ Abstract
Twisting monolayers of graphene with respect to each other has led to a number of unusual correlated states. This approach has inspired researchers to try their hand at twisting two-dimensional (2D) magnets, but such experiments have proven a difficult challenge. Song et al. made structures out of layers of the 2D magnet chromium triiodide with a small twist angle (see the Perspective by Lado). Using nitrogen vacancy centers in diamond as a magnetometer, the authors imaged the magnetic domains in both twisted monolayer and twisted trilayer structures. For twisted trilayers, a periodic pattern of ferromagnetic and antiferromagnetic domains was revealed.
Floquet Hamiltonian engineering of an isolated many-body spin system
孤立多体自旋系统的弗洛奎特哈密顿工程
▲ 作者：SEBASTIAN GEIER, NITHIWADEE THAICHAROEN, CLéMENT HAINAUT, TITUS FRANZ, ANDRE SALZINGER, XANNIKA TEBBEN, DAVID GRIMSHANDL, GERHARD ZüRN, AND MATTHIAS WEIDEMüLLER
▲ 链接：
https://www.science.org/doi/10.1126/science.abd9547
▲ 摘要
控制相互作用是多体系统量子工程的关键要素 。利用时间周期驱动 ， 一个封闭量子系统的自然给定的多体哈密顿量可以转化为一个表现出极大不同动力学特性的有效目标哈密顿量 。
作者在超冷的原子气体中用里德堡态代表的自旋系统来演示弗洛奎特工程 。通过应用一系列自旋操作 ， 他们改变了有效海森堡XYZ哈密顿量的对称性 。因此 ， 总自旋的松弛行为被极大地改变了 。
观测到的动力学可以用半经典模拟来定性地捕捉 。设计广泛的哈密顿量为在单一的实验设置中实现非平衡动力学的量子模拟提供了巨大的机会 。
▲ Abstract
Controlling interactions is the key element for the quantum engineering of many-body systems. Using time-periodic driving, a naturally given many-body Hamiltonian of a closed quantum system can be transformed into an effective target Hamiltonian that exhibits vastly different dynamics. We demonstrate such Floquet engineering with a system of spins represented by Rydberg states in an ultracold atomic gas. By applying a sequence of spin manipulations, we change the symmetry properties of the effective Heisenberg XYZ Hamiltonian. As a consequence, the relaxation behavior of the total spin is drastically modified. The observed dynamics can be qualitatively captured by a semiclassical simulation. Engineering a wide range of Hamiltonians opens vast opportunities for implementing quantum simulation of nonequilibrium dynamics in a single experimental setting.
化学Chemistry
Accelerated dinuclear palladium catalyst identification through unsupervised machine learning

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