Science, 14 JUL 2023, VOL 381, ISSUE 6654

《科学》2023年7月14日，第381卷，6654期

物理学Physics

Quantum metric nonlinear Hall effect in a topological ntiferromagnetic heterostructure

拓扑反铁磁异质结构中的量子度量非线性霍尔效应

▲ 作者：ANYUAN GAO, YU-FEI LIU, JIAN-XIANG QIU, BARUN GHOSH, THA?S V. TREVISAN, YUGO ONISHI, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.adf1506

▲ 摘要：

凝聚态物理学中的量子几何有两个组成部分：实部量子度量和虚部贝里曲率。虽然贝里曲率的影响已通过诸如二维电子气体中的量子霍尔效应和铁磁体中的反常霍尔效应（AHE）等现象被观察到，但量子度量却很少被探索。

研究组报道了量子度量偶极子通过将均匀层状的MnBi2Te4与黑磷界面连接而诱导的非线性霍尔效应。量子度量非线性霍尔效应在反铁磁（AFM）自旋反转时切换方向，并表现出与散射时间无关的明显标度。

该研究结果为发现理论预测的量子度量响应打开了大门，并为连接非线性电子学和AFM自旋电子学的应用奠定了基础。

▲ Abstract：

Quantum geometry in condensed-matter physics has two components: the real part quantum metric and the imaginary part Berry curvature. Whereas the effects of Berry curvature have been observed through phenomena such as the quantum Hall effect in two-dimensional electron gases and the anomalous Hall effect (AHE) in ferromagnets, the quantum metric has rarely been explored. Here, we report a nonlinear Hall effect induced by the quantum metric dipole by interfacing even-layered MnBi2Te4 with black phosphorus. The quantum metric nonlinear Hall effect switches direction upon reversing the antiferromagnetic (AFM) spins and exhibits distinct scaling that is independent of the scattering time. Our results open the door to discovering quantum metric responses predicted theoretically and pave the way for applications that bridge nonlinear electronics with AFM spintronics.

Quantum vortices of strongly interacting photons

强相互作用光子的量子漩涡

▲ 作者：LEE DRORI, BANKIM CHANDRA DAS, TOMER DANINO ZOHAR, GAL WINER, EILON POEM, ALEXANDER PODDUBNY, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.adh5315

▲ 摘要：

涡旋是拓扑上的非平凡缺陷，通常源于非线性场动力学。光子涡旋（电磁场相位奇点）的全光学产生需要足够强的非线性，这通常在经典光学领域中实现。

研究组报道了在量子非线性光学介质中实现由强光子-光子相互作用产生的光子量子漩涡。这种相互作用使共传播光子的相位积累更快，在双光子波函数内产生量子涡旋-反涡旋对。对于三个光子，涡线和中心涡环的形成证实了真正的三光子相互作用的存在。

波函数拓扑由双光子和三光子束缚态控制，施加每个光子π的条件相移，这是确定性量子逻辑运算的潜在资源。

▲ Abstract：

Vortices are topologically nontrivial defects that generally originate from nonlinear field dynamics. All-optical generation of photonic vortices—phase singularities of the electromagnetic field—requires sufficiently strong nonlinearity that is typically achieved in the classical optics regime. We report on the realization of quantum vortices of photons that result from a strong photon-photon interaction in a quantum nonlinear optical medium. The interaction causes faster phase accumulation for copropagating photons, producing a quantum vortex-antivortex pair within the two-photon wave function. For three photons, the formation of vortex lines and a central vortex ring confirms the existence of a genuine three-photon interaction. The wave function topology, governed by two- and three-photon bound states, imposes a conditional phase shift of π per photon, a potential resource for deterministic quantum logic operations.

Correlating the charge-transfer gap to the maximum transition temperature in Bi2Sr2Can-1CunO2n+4+δ

Bi2Sr2Can-1CunO2n+4+δ中电荷转移间隙与最大转变温度的相关性

▲ 作者：ZECHAO WANG, CHANGWEI ZOU, CHENGTIAN LIN, XIANGYU LUO, HONGTAO YAN, CHAOHUI YIN, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.add3672

▲ 摘要：

随着铜酸盐家族各晶胞中CuO2层数n的增加，最大转变温度（Tc,max）呈现出普遍的钟形曲线，在n=3处达到峰值。这种趋势的微观机制仍不明确。

在该研究中，研究组使用先进的电子显微镜对1≤n≤9的Bi2Sr2Can-1CunO2n+4+δ家族铜酸盐原子结构进行了成像；可同时测量电荷转移间隙尺寸（Δ）随n的变化。并确定Δ的n依赖性遵循倒钟形曲线，在n=3时Δ值最小。Δ、n和Tc,max之间的相关性可以阐明铜酸盐中超导性的起源。

▲ Abstract：

As the number of CuO2layers, n, in each unit cell of a cuprate family increases, the maximum transition temperature (Tc,max) exhibits a universal bell-shaped curve with a peak at n = 3. The microscopic mechanism of this trend remains elusive. In this study, we used advanced electron microscopy to image the atomic structure of cuprates in the  Bi2Sr2Can-1CunO2n+4+δfamily with 1 ≤ n ≤ 9; the evolution of the charge-transfer gap size (Δ) with n can be measured simultaneously. We determined that the n dependence of Δ follows an inverted bell-shaped curve with the minimum Δ value at n = 3. The correlation between Δ, n, and  Tc,max may clarify the origin of superconductivity in cuprates.

人工智能Artificial Intelligence

IExperimental evidence on the productivity effects of generative artificial intelligence

生成式人工智能对生产率影响的实验证据

▲ 作者：SHAKKED NOY AND WHITNEY ZHANG.

▲ 链接：

https://www.science.org/doi/10.1126/science.adh2586

▲ 摘要：

研究组探讨了一种生成式人工智能（AI）技术，即辅助聊天机器人ChatGPT在中级专业写作任务背景下的生产率效应。

在一项预先注册的在线实验中，研究组给453名受过大学教育的专业人士分配了特定职业的激励性写作任务，并随机让其中一半人接触ChatGPT。

该研究结果表明，ChatGPT极大地提高了生产率：平均耗时减少了40%，产出质量提高了18%。劳动者之间的不平等减少了，而对AI的担忧和兴奋暂时上升。

在实验期间接触ChatGPT的员工报告称，实验两周后在实际工作中使用ChatGPT的可能性是原先的两倍，实验两个月后为1.6倍。

▲ Abstract：

We examined the productivity effects of a generative artificial intelligence (AI) technology, the assistive chatbot ChatGPT, in the context of midlevel professional writing tasks. In a preregistered online experiment, we assigned occupation-specific, incentivized writing tasks to 453 college-educated professionals and randomly exposed half of them to ChatGPT. Our results show that ChatGPT substantially raised productivity: The average time taken decreased by 40% and output quality rose by 18%. Inequality between workers decreased, and concern and excitement about AI temporarily rose. Workers exposed to ChatGPT during the experiment were 2 times as likely to report using it in their real job 2 weeks after the experiment and 1.6 times as likely 2 months after the experiment.

材料科学Materials Science

Engineering ligand reactivity enables high-temperature operation of stable perovskite solar cells

工程配体反应性实现稳定钙钛矿太阳能电池的高温运行

▲ 作者：SO MIN PARK, MINGYANG WEI, JIAN XU, HARINDI R. ATAPATTU, FELIX T. EICKEMEYER, KASRA DARABI, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.adi4107

▲ 摘要：

钙钛矿太阳能电池（PSCs）由包含铵配体插层的界面二维和三维异质结构组成，已朝着将性能与稳定性相结合的目标取得了快速进展。然而，随着该领域继续寻求更高的耐久性，需要额外工具来避免配体嵌入，以最大限度地减少高温下的降解。

研究组使用与大部分钙钛矿不反应的铵配体，并系统地研究了一个改变配体分子结构的库。他们发现氟化苯胺提供界面钝化，同时最小化与钙钛矿的反应性，利用这种方法获得了倒置结构PSCs的认证准稳态功率转换效率为24.09%。

在85℃和50%相对湿度下工作的封装设备中，研究组记录了在1倍太阳光照、最大功率点的T85高达1560小时。

▲ Abstract：

Perovskite solar cells (PSCs) consisting of interfacial two- and three-dimensional heterostructures that incorporate ammonium ligand intercalation have enabled rapid progress toward the goal of uniting performance with stability. However, as the field continues to seek ever-higher durability, additional tools that avoid progressive ligand intercalation are needed to minimize degradation at high temperatures. We used ammonium ligands that are nonreactive with the bulk of perovskites and investigated a library that varies ligand molecular structure systematically. We found that fluorinated aniliniums offer interfacial passivation and simultaneously minimize reactivity with perovskites. Using this approach, we report a certified quasi–steady-state power-conversion efficiency of 24.09% for inverted-structure PSCs. In an encapsulated device operating at 85°C and 50% relative humidity, we document a 1560-hour T85 at maximum power point under 1-sun illumination.

Multiplex CRISPR editing of wood for sustainable fiber production

多重CRISPR编辑的木材用于可持续纤维生产

▲ 作者：DANIEL B. SULIS, XIAO JIANG, CHENMIN YANG, BARBARA M. MARQUES, MEGAN L. MATTHEWS, ZACHARY MILLER, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.add4514

▲ 摘要：

长期以来，由于木质素的复杂性和可塑性，木材中的生物聚合物木质素难以被化学和酶降解，阻碍了对森林树木进行更可持续的纤维生物经济驯化。

研究组展示了多重CRISPR编辑可以精确设计木材原料，以组合改善木质素成分和木材性能。通过评估21个木质素生物合成基因的69123种多基因编辑策略的每种可能组合，研究组推导出针对多达6个基因同时改变的7种不同的基因组编辑策略，并产生174种编辑过的杨树变异体。

CRISPR编辑将木材碳水化合物与木质素的比例提高到野生型的228%，从而提高了纤维制浆的效率。无论树木生长速度如何变化，经过编辑的木材都缓解了主要的纤维生产瓶颈，并有望带来前所未有的运营效率、生物经济机遇和环境效益。

▲ Abstract：

The domestication of forest trees for a more sustainable fiber bioeconomy has long been hindered by the complexity and plasticity of lignin, a biopolymer in wood that is recalcitrant to chemical and enzymatic degradation. Here, we show that multiplex CRISPR editing enables precise woody feedstock design for combinatorial improvement of lignin composition and wood properties. By assessing every possible combination of 69,123 multigenic editing strategies for 21 lignin biosynthesis genes, we deduced seven different genome editing strategies targeting the concurrent alteration of up to six genes and produced 174 edited poplar variants. CRISPR editing increased the wood carbohydrate-to-lignin ratio up to 228% that of wild type, leading to more-efficient fiber pulping. The edited wood alleviates a major fiber-production bottleneck regardless of changes in tree growth rate and could bring unprecedented operational efficiencies, bioeconomic opportunities, and environmental benefits.