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物理学Physics

Scalable entanglement of nuclear spins mediated by electron exchange

电子互换介导的核自旋可扩大纠缠

▲ 作者：HOLLY G. STEMP, MARK R. VAN BLANKENSTEIN, SERWAN ASAAD, MATEUSZ T. M?DZIK, BENJAMIN JOECKER, HANNES R. FIRGAU, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.ady3799

▲择要：核自旋于量子计较中的运用受限在难以于远间隔原子核间创立真实的量子纠缠。今朝半导体中的核纠缠依靠在原子核与共用电子的耦合，这并不是一种可扩大的计谋。

于这项事情中，研究组展示了于硅器件中相距20纳米以上的两个磷原子核之间双量子位节制的Z逻辑门运算。每一个原子联合自力电子，其互换彼此作用介导了原子核的双量子位门。

研究组制备并丈量了一个核贝尔态，保真度为76+5-5%，共轭度为0.67+0.05-0.05。经由过程这类要领，将来扩展半导体自旋量子比特的进展可扩大到基在核自旋的量子计较机的开发。

▲ Abstract：The use of nuclear spins for quantum computation is limited by the difficulty in creating genuine quantum entanglement between distant nuclei. Current demonstrations of nuclear entanglement in semiconductors rely on coupling the nuclei to a co妹妹on electron, which is not a scalable strategy. In this work, we demonstrated a two-qubit controlled-Z logic operation between the nuclei of two phosphorus atoms in a silicon device, separated by up to 20 nanometers. Each atom binds separate electrons, whose exchange interaction mediates the nuclear two-qubit gate. We prepared and measured a nuclear Bell state with a fidelity of 76+5-5% and a concurrence of 0.67+0.05-0.05. With this method, future progress in scaling up semiconductor spin qubits can be extended to the development of nuclear spin based quantum computers.

Quantum squeezing of a levitated nanomechanical oscillator

悬浮纳米机械振荡器的量子压缩

▲ 作者：Mitsuyoshi Kamba, Naoki Hara and Kiyotaka Aikawa

▲链接：

https://www.science.org/doi/10.1126/science.ady4652

▲择要：于基础物理学、传感及换能器等多个范畴，把持宏不雅物体于其量子力学不确定性四周的运动一直是人们寻求的方针。只管于悬浮固体颗粒的基态冷却方面取患了进展，但实现其非经典态仍是一个难题。

研究组经由过程快速转变单个纳米粒子的振荡频率来演示其运动状况的量子压缩。他们发明，利用自由膨胀丈量，速率方差较着收窄到基态的-4.9 0.1分贝。

该事情注解，悬浮纳米颗粒为研究运动的非经典态提供了抱负的平台，并为于宏不雅标准上开发量子传感及摸索量子力学的运用斥地了一条新路子。

▲ Abstract：Manipulating the motion of macroscopic objects near their quantum mechanical uncertainties has been desired in diverse fields, including fundamental physics, sensing, and transducers. Despite progress in ground-state cooling of a levitated solid particle, realizing its nonclassical states has been elusive. Here, we demonstrate quantum squeezing of the motion of a single nanoparticle by rapidly varying its oscillation frequency. We reveal appreciable narrowing of the velocity variance to 4.9 0.1 decibels of that of the ground state using free-expansion measurements. Our work shows that a levitated nanoparticle offers an ideal platform for studying nonclassical states of its motion and provides a route to developing applications in quantum sensing and exploring quantum mechanics at a macroscopic scale.

化学Chemistry

Stereo-reversed E2 unlocks Z-selective C functionalization

立体反转E2解锁Z选择性C-H官能化

▲ 作者：Peter J. Verardi, Elizabeth A. Ryutov, Poulami Mukherjee, Remy Lalisse, Karina Targos, Tetsuya Inagaki, et al.

▲链接：

https://www.science.org/doi/10.1126/science.adv7630

▲择要：C-H键的立体选择性官能化是现代有机合成中的一个焦点挑战。只管C-H活化化学已经历经几十年的立异，但合成化学家仍未实现烯烃的Z选择性官能化计谋。结尾烯烃对于Z选择性组成了最年夜的挑战，因其需要选择性裂解两个险些不异的C-H键中位阻更年夜的键。

研究组描写了烯烃转化为颠末Z选择性消弭的瞬态1,2-双锍中间体，经由过程不变彼此作用倾覆了教科书级的E2立体选择性法则。他们将配对于电解确定为一种使能计谋，既可以选择性地孕育发生所需的双锍中间体，又可将其于原位快速消弭。

由此孕育发生的Z-烯基锍要害体经由过程稳健的交织偶联反映，从廉价的原猜中得到广泛的Z-烯烃方针。

▲ Abstract：The stereoselective functionalization of C H bonds represents a central challenge in modern organic synthesis. Despite decades of innovation in C H activation chemistry, methods for Z-selective functionalization of alkenes have eluded synthetic practitioners. Terminal alkenes present the biggest challenge for Z-selectivity as they require selective cleavage of the more hindered of two otherwise virtually identical C H bonds. Herein, we describe the transformation of alkenes into transient 1,2-bis-sulfonium intermediates found to undergo Z-selective elimination, overturning a textbook E2 stereoselectivity rule through stabilizing interactions. We identify paired electrolysis as an enabling strategy to both selectively generate the requisite bis-sulfonium intermediate and drive its rapid elimination in situ. The resultant Z-alkenyl sulfonium linchpins provide access to a wide array of Z-alkene targets from inexpensive feedstocks through robust cross-coupling reactions.

High-capacity, reversible hydrogen storage using H -conducting solid electrolytes

利用H-导电固体电解质的高容量可逆储氢

▲ 作者：Takashi Hirose, Naoki Matsui, Takashi Itoh, Yoyo Hinuma, Kazutaka Ikeda, Kazuma Gotoh, et al.

▲链接：

https://www.science.org/doi/10.1126/science.adw1996

▲择要：固体中氢的吸赞同脱附是电池及储氢装配中触及的要害反映。然而，传统的利用高容量质料的热力学及电化学储氢技能存于脱氢温度高及电解质不不变的问题。

研究组摸索了氢离子（H-）驱动的电化学储氢，开发了一种具备优秀H-导电性及电化学不变性的固体电解质：反 -AgI型Ba0.5Ca0.35Na0.15H1.85。这类电解质与几种金属氢电极兼容，如氢化钛及氢化镁（MgH2），可于低温下实现高容量可逆储氢。

详细而言，Mg-H2电池作为储氢装配（Mg + H2 = MgH2）于90℃下实现了每一克2030毫安时的可逆容量，实现了安全高效的氢-电转换及储氢装配。

▲ Abstract：Hydrogen absorption and desorption in solids are pivotal reactions involved in batteries and hydrogen storage devices. However, c三木SEO-onventional thermodynamic and electrochemical hydrogen storage using high-capacity materials suffers from high hydrogen-desorption temperatures and instability of electrolytes. In this work, we explored electrochemical hydride ion (H ) driven hydrogen storage and developed a solid electrolyte, anti -AgI type Ba0.5Ca0.35Na0.15H1.85, which exhibits excellent H conductivity and electrochemical stability. This electrolyte is compatible with several metal-hydrogen electrodes, such as titanim hydride and magnesium hydride (MgH2), allowing for high-capacity, reversible hydrogen storage at low temperatures. Specifically, Mg H2 cells operating as hydrogen storage devices (Mg + H2 = MgH2) achieved a reversible capacity of 2030 milliampere hours per gram at 90 C, offering safe and efficient hydrogen-electricity conversion and hydrogen storage devices.

地球科学Earth Science

Crustal stresses and damage evolve throughout the seismic cycle of the Ridgecrest fault zone

地壳应力及粉碎于里奇克雷斯特断裂带的整个地动周期中不停演化

▲ 作者：JARED BRYAN, WILLIAM B. FRANK AND PASCAL AUDET

▲链接：

https://www.science.org/doi/10.1126/science.adu9116

▲择要：地动经由过程断层及周围地壳的耦合演化，会忽然开释出随时间迟缓堆集的组织应力。地动波速跟踪地壳变形及应力变化，但典型的监测要领对于浅层最敏感。

使用吸收器函数，研究组跟踪了2019年里奇克雷斯专程震序列时期整个地壳分裂带波速及各向异性变化。浅层同震波速降落于数月内恢复，而更深层的震后波速降落连续数年，未见可丈量的恢复。

深而长期的波速降落可能反应了震后变形驱动的累积侵害，这提出了两种可能的环境：（i）波速及各向异性跟踪持久应力演化的迟缓震间恢复；或者（ii）未成熟断裂带的永世变形。这两种环境城市影响地动周期的动力学及能量分配。

▲ Abstract：Earthquakes abruptly release tectonic stress that builds slowly over time through the coupled evolution of faults and the surrounding crust. Seismic wavespeeds track crustal deformation and stress changes, but typical monitoring methods are most sensitive to shallow depths. Using receiver functions, we tracked rupture-zone wavespeed and anisotropy changes throughout the crust during the 2019 Ridgecrest earthquake sequence. Shallow coseismic wavespeed reductions recovered within months, whereas a deeper postseismic wavespeed drop persisted without measurable recovery over several years. The deep, persistent wavespeed drop likely reflects accumulating damage driven by postseismic deformation, suggesting two possible scenarios: (i) a slow interseismic recovery where wavespeed and anisotropy track long-term stress evolution; or (ii) permanent deformation of an i妹妹ature fault zone. Both scenarios affect the dynamics and energy budget of the seismic cycle.

More extreme Indian monsoon rainfall in El Ni o su妹妹ers

厄尔尼诺夏日印度季风降雨更极度

▲ 作者：SPENCER A. HILL, DESTINY ZAMIR MEYERS, ADAM H. SOBEL, MICHELA BIASUTTI, MARK A. CANE, MICHAEL K. TIPPETT, ET AL.

▲链接：

https://www.science.org/doi/10.1126/science.adg5577

▲择要：印度夏日季风时期的极度降雨对于这个世界第三年夜经济体及人口至多的国度造成粉碎性及致命性的影响。

虽然已经知赤道承平洋的厄尔尼诺征象按捺了整个印度的夏日总降雨量，但研究组利用1901~2020年的不雅测数据注解，与直觉相反，它们同时加重了极度日降雨量。该征象部门归因在对于流浮力的极度日值增长，条件是思量到近地面空气的未稀释不不变性以和与上层干燥空气混淆而孕育发生的稀释。

厄尔尼诺可能会于其他热带地域激发近似的变化，该框架可进一步运用在每一小时极值的变化、其他内部变率模式，以和天气变化驱动的强制趋向。

▲ Abstract：Extreme rainfall during the Indian su妹妹er monsoon can be destructive and deadly to the world s third-largest economy and most populous country. Although El Ni?o events in the equatorial Pacific are known to suppress total su妹妹er rainfall throughout India, we show using observational data spanning 1901 to 2020 that, counterintuitively, they simultaneously intensify extreme daily rainfall. This is partly driven by increases in extreme daily values of convective buoyancy, provided that both the undilute instability of near-surface air and the dilution by mixing with drier air above are considered. El Ni?o could plausibly drive similar changes in other tropical regions, and our framework could be further applied to changes in hourly extremes, to other internal variability modes, and to forced trends under climate change.

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