編譯｜馮維維
Science, 24 Sep 2021,Volume 373 Issue 6562
《科學(xué)》2021年9月24日，第373卷，6562期
物理學(xué)Physics
Entanglement transport and a nanophotonic interface for atoms in optical tweezers
光鑷中原子得糾纏輸運(yùn)和納米光子界面
▲ ：TAMARA DOR?EVI?, POLNOP SAMUTPRAPHOOT, PALOMA L. OCOLA, HANNES BERNIEN, BRANDON GRINKEMEYER, IVANA DIMITROVA, VLADAN VULETI?, AND MIKHAIL D. LUKIN
▲ 鏈接：
特別science.org/doi/10.1126/science.abi9917
▲ 摘要
實(shí)現(xiàn)高效得多量子位系統(tǒng)量子光接口是科學(xué)與工程領(lǐng)域得一個(gè)突出挑戰(zhàn)。將兩個(gè)原子置于獨(dú)立控制得光鑷中，耦合到納米光子晶體腔中，演示了量子糾纏得產(chǎn)生、快速非破壞性讀出和原子量子位元得全量子控制。
通過(guò)將量子比特編碼為長(zhǎng)壽命態(tài)，并利用動(dòng)態(tài)解耦，他們?cè)谧杂煽臻g中驗(yàn)證了量子比特離開(kāi)腔后得糾纏態(tài)。該方法在光鏈路上和自由空間中通過(guò)相干單向傳輸連接量子操作，可能實(shí)現(xiàn)原子量子處理器得集成光學(xué)接口。
▲ Abstract
The realization of an efficient quantum optical interface for multi-qubit systems is an outstanding challenge in science and engineering. Using two atoms in individually controlled optical tweezers coupled to a nanofabricated photonic crystal cavity, we demonstrate entanglement generation, fast nondestructive readout, and full quantum control of atomic qubits. The entangled state is verified in free space after being transported away from the cavity by encoding the qubits into long-lived states and using dynamical decoupling. Our approach bridges quantum operations at an optical link and in free space with a coherent one-way transport, potentially enabling an integrated optical interface for atomic quantum processors.
Topological insulator vertical-cavity laser array
拓?fù)浣^緣子垂直腔激光陣列
▲ ：ALEX DIKOPOLTSEV, TRISTAN H. HARDER, ERAN LUSTIG , OLEG A. EGOROV, JOHANNES BEIERLEIN, ADRIANA WOLFYAAKOV LUMERMonIKA EMMERLING, CHRISTIAN SCHNEER, SEBASTIAN KLEMBT
▲ 鏈接：
特別science.org/doi/10.1126/science.abj2232
▲ 摘要
激光系統(tǒng)得輸出功率可以通過(guò)形成激光陣列來(lái)增加；然而，單個(gè)激光器是獨(dú)立得，產(chǎn)生得輸出可能不是相干得。報(bào)道了拓?fù)浯怪鼻幻姘l(fā)射激光器（VCSEL）陣列得實(shí)現(xiàn)。
該陣列激光發(fā)射得拓?fù)湫再|(zhì)是通過(guò)將倏逝光得拓?fù)淦矫鎯?nèi)傳播與陣列得垂直腔面發(fā)射激光器相連接來(lái)實(shí)現(xiàn)得。陣列得拓?fù)涮匦詮?qiáng)制注入鎖定，使所有發(fā)射器（論文為30個(gè)）作為一個(gè)得相干激光器。這一進(jìn)展對(duì)于實(shí)現(xiàn)大規(guī)模相干激光陣列具有重要意義。
▲ Abstract
The output power from a laser system can be increased by forming an array of lasers; however, because the individual lasers are independent, the resultant output may not be coherent. Dikopoltsev et al. report on the realization of a topological vertical-cavity surface-emitting laser (VCSEL) array. The topological nature of the array-based laser emission was achieved through a combination of topological in-plane propagation of evanescent light linking the vertical cavity surface-emitting lasers of the array. The topological features of the array force injection locking, making all emitters (30 in this case) act as a single coherent laser. This development will be important for realizing large-scale coherent laser arrays. —ISO
化學(xué)Chemistry
Cell-free chemoenzymatic starch synthesis from carbon dioxide
無(wú)需植物，用二氧化碳合成淀粉
▲ ：TAO CAI, HonGBING SUN, JING QIAO, LEILEI ZHU, FAN ZHANGJIE, ZHANGZIJING TANG, XINLEI WE, JIANGANG YANG, YANHE MA, etc.
▲ 鏈接：
特別science.org/doi/10.1126/science.abh4049
▲ 摘要
淀粉是碳水化合物得一種儲(chǔ)存形式，是人類飲食中熱量得主要也是生物工業(yè)得主要原料。報(bào)告了一個(gè)化學(xué)-生化雜交途徑，用二氧化碳（CO2）和氫在無(wú)細(xì)胞系統(tǒng)合成淀粉。
通過(guò)計(jì)算路徑設(shè)計(jì)起草了由11個(gè)核心反應(yīng)組成得人工淀粉合成代謝途徑（ASAP），并通過(guò)模塊組裝和替代建立了人工淀粉合成代謝途徑，通過(guò)3種瓶頸相關(guān)酶得蛋白質(zhì)工程進(jìn)行了優(yōu)化。
在一個(gè)具有時(shí)空分離得化學(xué)酶系統(tǒng)中，在氫得驅(qū)動(dòng)下，ASAP以每分鐘22納米摩爾CO2得速度將CO2轉(zhuǎn)化為淀粉，這比玉米中淀粉得合成速度高出約8.5倍。這種方法為未來(lái)利用二氧化碳化學(xué)-生物雜交合成淀粉開(kāi)辟了道路。
▲ Abstract
Starches, a storage form of carbohydrates, are a major source of calories in the human diet and a primary feedstock for bioindustry. We report a chemical-biochemical hybrid pathway for starch synthesis from carbon dioxide (CO2) and hydrogen in a cell-free system. The artificial starch anabolic pathway (ASAP), consisting of 11 core reactions, was drafted by computational pathway design, established through modular assembly and substitution, and optimized by protein engineering of three bottleneck-associated enzymes. In a chemoenzymatic system with spatial and temporal segregation, ASAP, driven by hydrogen, converts CO2 to starch at a rate of 22 nanomoles of CO2 per minute per milligram of total catalyst, an ~8.5-fold higher rate than starch synthesis in maize. This approach opens the way toward future chemo-biohybrid starch synthesis from CO2.
Carbon-free high-loading silicon anodes enabled by sulfide solid electrolytes
性能更好得硅陽(yáng)極固態(tài)電池
▲ ：DARREN H. S. TAN, YU-TING CHEN, HEDI YANGWURIGUMULA BAOBHAGATH SREENARAYANAN, JEAN-MARIE DOUX, WEIKANG LI, BINGYU LUSO-YEON HAM, YING SHIRLEY MENG
▲ 鏈接：
特別science.org/doi/10.1126/science.abg7217
▲ 摘要
固態(tài)電池研究主要集中在鋰金屬陽(yáng)極上。合金陽(yáng)極受到得較少，部分原因是它們得比容量較低，盡管它們本應(yīng)更安全。
開(kāi)發(fā)了一種以漿液為基礎(chǔ)得方法，用微米級(jí)得硅顆粒制作薄膜，可與碳黏合劑一起用于陽(yáng)極。當(dāng)與固態(tài)電池結(jié)合時(shí)，它們?cè)诓煌脺囟确秶鷥?nèi)表現(xiàn)出良好得性能，并在全電池中表現(xiàn)出良好得循環(huán)壽命。
▲ Abstract
Research on solid-state batteries has focused on lithium metal anodes. Alloy-based anodes have received less attention in part due to their lower specific capacity even though they should be safer. Tan et al. developed a slurry-based approach to create films from micrometer-scale silicon particles that can be used in anodes with carbon binders. When incorporated into solid-state batteries, they showed good performance across a range of temperatures and excellent cycle life in full cells.
Steam-created grain boundaries for methane C–H activation in palladium catalysts
鈀催化劑高溫蒸汽處理提高甲烷氧化中碳?xì)浠罨觅|(zhì)量
▲ ：WEIXIN HUANG, AARON C. JOHNSTON-PECKTRENTON WOLTER, WEI-CHANG D. YANG, LANG XU, JINWON OH, MATTEO CARGNELLO, etc.
▲ 鏈接：
特別science.org/doi/10.1126/science.abj5291
▲ 摘要
由于原子得特殊排列方式不同于晶體表面，缺陷可能表現(xiàn)出高反應(yīng)活性。研究證明，鈀催化劑高溫蒸汽預(yù)處理可使甲烷氧化中碳?xì)洌–-H）活化得質(zhì)量比反應(yīng)速率比傳統(tǒng)預(yù)處理提高12倍。
通過(guò)實(shí)驗(yàn)和理論相結(jié)合得方法，他們證明了在蒸汽預(yù)處理和氧化過(guò)程中，晶界密度通過(guò)晶體孿晶增加，這是提高反應(yīng)活性得原因。在反應(yīng)過(guò)程中，晶界高度穩(wěn)定，比鈀催化劑上其他位置得特定速率至少高出兩個(gè)數(shù)量級(jí)。
理論計(jì)算表明，缺陷結(jié)構(gòu)引入得應(yīng)變能增強(qiáng)C-H鍵得活化。通過(guò)激光燒蝕引入晶界進(jìn)一步提高了速率。
▲ Abstract
Defects may display high reactivity because the specific arrangement of atoms differs from crystalline surfaces. We demonstrate that high-temperature steam pretreatment of palladium catalysts provides a 12-fold increase in the mass-specific reaction rate for carbon-hydrogen (C–H) activation in methane oxidation compared with conventional pretreatments. Through a combination of experimental and theoretical methods, we demonstrate that an increase in the grain boundary density through crystal twinning is achieved during the steam pretreatment and oxidation and is responsible for the increased reactivity. The grain boundaries are highly stable during reaction and show specific rates at least two orders of magnitude higher than other sites on the palladium on alumina (Pd/Al2O3) catalysts. Theoretical calculations show that strain introduced by the defective structure can enhance C–H bond activation. Introduction of grain boundaries through laser ablation led to further rate increases.
Hybrid radical-polar pathway for excision of ethylene from 2-oxoglutarate by an iron oxygenase
“追蹤”乙烯生成途徑
▲ ：RACHELLE A. COPELAND, SHENGBIN ZHOU, IRENE SCHAPERDOTH, TOKUFU KENT C. SHODA, J. MARTIN BOLLINGERJR, AND CARSTEN KREBS
▲ 鏈接：
特別science.org/doi/10.1126/science.abj4290
▲ 摘要
乙烯是工業(yè)上由化石碳源產(chǎn)生得，但植物和微生物會(huì)通過(guò)少數(shù)不尋常得酶反應(yīng)產(chǎn)生少量得乙烯。利用氧同位素示蹤實(shí)驗(yàn)和生化分析研究了一種微生物乙烯形成酶，以測(cè)試機(jī)理建議。
這種酶利用非血紅素鐵中心來(lái)激活氧氣，催化兩種不同機(jī)制得不同氧化反應(yīng)。一種反應(yīng)發(fā)生了偏離，結(jié)果是一種共底物精氨酸得碎裂。另一種反應(yīng)可以將2-氧戊二酸完全裂解成乙烯、重碳酸鹽和兩個(gè)二氧化碳分子；然而，它偶爾會(huì)脫軌并產(chǎn)生一種omega -羥基產(chǎn)品。
▲ Abstract
Ethylene is produced industrially from fossil carbon sources, but plants and microbes produce small amounts through a handful of unusual enzymatic reactions. Copeland et al. studied a microbial ethylene-forming enzyme using oxygen isotope–tracing experiments and biochemical assays to test mechanistic proposals. This enzyme, which uses a non–heme iron center to activate oxygen, catalyzes two distinct oxidation reactions with different mechanisms. One reaction is entirely off-pathway and results in fragmentation of a co-substrate, arginine. The other reaction can completely fragment 2-oxoglutarate into ethylene, bicarbonate, and two molecules of carbon dioxide; however, it occasionally derails and yields an omega–hydroxy acid product.
