原文地址：http://news.sciencenet.cn/htmlnews/2023/7/504851.shtm
Science, 14 JUL 2023, VOL 381, ISSUE 6654
《科學》2023年7月14日，第381卷，6654期
物理學Physics
Quantum metric nonlinear Hall effect in a topological ntiferromagnetic heterostructure
拓撲反鐵磁異質結構中的量子度量非線性霍爾效應
▲ 作者：ANYUAN GAO, YU-FEI LIU, JIAN-XIANG QIU, BARUN GHOSH, THA?S V. TREVISAN, YUGO ONISHI, ET AL.
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▲ 摘要：
凝聚態物理學中的量子幾何有兩個組成部分：實部量子度量和虛部貝里曲率。雖然貝里曲率的影響已通過諸如二維電子氣體中的量子霍爾效應和鐵磁體中的反常霍爾效應（AHE）等現象被觀察到，但量子度量卻很少被探索。
研究組報道了量子度量偶極子通過將均勻層狀的MnBi2Te4與黑磷界面連接而誘導的非線性霍爾效應。量子度量非線性霍爾效應在反鐵磁（AFM）自旋反轉時切換方向，并表現出與散射時間無關的明顯標度。
該研究結果為發現理論預測的量子度量響應打開了大門，并為連接非線性電子學和AFM自旋電子學的應用奠定了基礎。
▲ 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
強相互作用光子的量子漩渦
▲ 作者：LEE DRORI, BANKIM CHANDRA DAS, TOMER DANINO ZOHAR, GAL WINER, EILON POEM, ALEXANDER PODDUBNY, ET AL.
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渦旋是拓撲上的非平凡缺陷，通常源于非線性場動力學。光子渦旋（電磁場相位奇點）的全光學產生需要足夠強的非線性，這通常在經典光學領域中實現。
研究組報道了在量子非線性光學介質中實現由強光子-光子相互作用產生的光子量子漩渦。這種相互作用使共傳播光子的相位積累更快，在雙光子波函數內產生量子渦旋-反渦旋對。對于三個光子，渦線和中心渦環的形成證實了真正的三光子相互作用的存在。
波函數拓撲由雙光子和三光子束縛態控制，施加每個光子π的條件相移，這是確定性量子邏輯運算的潛在資源。
▲ 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中電荷轉移間隙與最大轉變溫度的相關性
▲ 作者：ZECHAO WANG, CHANGWEI ZOU, CHENGTIAN LIN, XIANGYU LUO, HONGTAO YAN, CHAOHUI YIN, ET AL.
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隨著銅酸鹽家族各晶胞中CuO2層數n的增加，最大轉變溫度（Tc,max）呈現出普遍的鐘形曲線，在n=3處達到峰值。這種趨勢的微觀機制仍不明確。
在該研究中，研究組使用先進的電子顯微鏡對1≤n≤9的Bi2Sr2Can-1CunO2n+4+δ家族銅酸鹽原子結構進行了成像；可同時測量電荷轉移間隙尺寸（Δ）隨n的變化。并確定Δ的n依賴性遵循倒鐘形曲線，在n=3時Δ值最小。Δ、n和Tc,max之間的相關性可以闡明銅酸鹽中超導性的起源。
▲ 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
生成式人工智能對生產率影響的實驗證據
▲ 作者：SHAKKED NOY AND WHITNEY ZHANG.
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研究組探討了一種生成式人工智能（AI）技術，即輔助聊天機器人ChatGPT在中級專業寫作任務背景下的生產率效應。
在一項預先注冊的在線實驗中，研究組給453名受過大學教育的專業人士分配了特定職業的激勵性寫作任務，并隨機讓其中一半人接觸ChatGPT。
該研究結果表明，ChatGPT極大地提高了生產率：平均耗時減少了40%，產出質量提高了18%。勞動者之間的不平等減少了，而對AI的擔憂和興奮暫時上升。
在實驗期間接觸ChatGPT的員工報告稱，實驗兩周后在實際工作中使用ChatGPT的可能性是原先的兩倍，實驗兩個月后為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.
材料科學Materials Science
Engineering ligand reactivity enables high-temperature operation of stable perovskite solar cells
工程配體反應性實現穩定鈣鈦礦太陽能電池的高溫運行
▲ 作者：SO MIN PARK, MINGYANG WEI, JIAN XU, HARINDI R. ATAPATTU, FELIX T. EICKEMEYER, KASRA DARABI, ET AL.
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鈣鈦礦太陽能電池（PSCs）由包含銨配體插層的界面二維和三維異質結構組成，已朝著將性能與穩定性相結合的目標取得了快速進展。然而，隨著該領域繼續尋求更高的耐久性，需要額外工具來避免配體嵌入，以最大限度地減少高溫下的降解。
研究組使用與大部分鈣鈦礦不反應的銨配體，并系統地研究了一個改變配體分子結構的庫。他們發現氟化苯胺提供界面鈍化，同時最小化與鈣鈦礦的反應性，利用這種方法獲得了倒置結構PSCs的認證準穩態功率轉換效率為24.09%。
在85℃和50%相對濕度下工作的封裝設備中，研究組記錄了在1倍太陽光照、最大功率點的T85高達1560小時。
▲ 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編輯的木材用于可持續纖維生產
▲ 作者：DANIEL B. SULIS, XIAO JIANG, CHENMIN YANG, BARBARA M. MARQUES, MEGAN L. MATTHEWS, ZACHARY MILLER, ET AL.
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長期以來，由于木質素的復雜性和可塑性，木材中的生物聚合物木質素難以被化學和酶降解，阻礙了對森林樹木進行更可持續的纖維生物經濟馴化。
研究組展示了多重CRISPR編輯可以精確設計木材原料，以組合改善木質素成分和木材性能。通過評估21個木質素生物合成基因的69123種多基因編輯策略的每種可能組合，研究組推導出針對多達6個基因同時改變的7種不同的基因組編輯策略，并產生174種編輯過的楊樹變異體。
CRISPR編輯將木材碳水化合物與木質素的比例提高到野生型的228%，從而提高了纖維制漿的效率。無論樹木生長速度如何變化，經過編輯的木材都緩解了主要的纖維生產瓶頸，并有望帶來前所未有的運營效率、生物經濟機遇和環境效益。
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