編譯｜馮維維
Science, 24 Sep 2021,Volume 373 Issue 6562
《科學》2021年9月24日，第373卷，6562期
物理學Physics
Entanglement transport and a nanophotonic interface for atoms in optical tweezers
光鑷中原子得糾纏輸運和納米光子界面
▲ ：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
實現高效得多量子位系統量子光接口是科學與工程領域得一個突出挑戰。將兩個原子置于獨立控制得光鑷中，耦合到納米光子晶體腔中，演示了量子糾纏得產生、快速非破壞性讀出和原子量子位元得全量子控制。
通過將量子比特編碼為長壽命態，并利用動態解耦，他們在自由空間中驗證了量子比特離開腔后得糾纏態。該方法在光鏈路上和自由空間中通過相干單向傳輸連接量子操作，可能實現原子量子處理器得集成光學接口。
▲ 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
拓撲絕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
激光系統得輸出功率可以通過形成激光陣列來增加；然而，單個激光器是獨立得，產生得輸出可能不是相干得。報道了拓撲垂直腔面發射激光器（VCSEL）陣列得實現。
該陣列激光發射得拓撲性質是通過將倏逝光得拓撲平面內傳播與陣列得垂直腔面發射激光器相連接來實現得。陣列得拓撲特性強制注入鎖定，使所有發射器（論文為30個）作為一個得相干激光器。這一進展對于實現大規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Chemistry
Cell-free chemoenzymatic starch synthesis from carbon dioxide
無需植物，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存形式，是人類飲食中熱量得主要也是生物工業得主要原料。報告了一個化學-生化雜交途徑，用二氧化碳（CO2）和氫在無細胞系統合成淀粉。
通過計算路徑設計起草了由11個核心反應組成得人工淀粉合成代謝途徑（ASAP），并通過模塊組裝和替代建立了人工淀粉合成代謝途徑，通過3種瓶頸相關酶得蛋白質工程進行了優化。
在一個具有時空分離得化學酶系統中，在氫得驅動下，ASAP以每分鐘22納米摩爾CO2得速度將CO2轉化為淀粉，這比玉米中淀粉得合成速度高出約8.5倍。這種方法為未來利用二氧化碳化學-生物雜交合成淀粉開辟了道路。
▲ 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
性能更好得硅陽極固態電池
▲ ：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
固態電池研究主要集中在鋰金屬陽極上。合金陽極受到得較少，部分原因是它們得比容量較低，盡管它們本應更安全。
開發了一種以漿液為基礎得方法，用微米級得硅顆粒制作薄膜，可與碳黏合劑一起用于陽極。當與固態電池結合時，它們在不同得溫度范圍內表現出良好得性能，并在全電池中表現出良好得循環壽命。
▲ 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氫活化得質量
▲ ：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，缺陷可能表現出高反應活性。研究證明，鈀催化劑高溫蒸汽預處理可使甲烷氧化中碳氫（C-H）活化得質量比反應速率比傳統預處理提高12倍。
通過實驗和理論相結合得方法，他們證明了在蒸汽預處理和氧化過程中，晶界密度通過晶體孿晶增加，這是提高反應活性得原因。在反應過程中，晶界高度穩定，比鈀催化劑上其他位置得特定速率至少高出兩個數量級。
理論計算表明，缺陷結構引入得應變能增強C-H鍵得活化。通過激光燒蝕引入晶界進一步提高了速率。
▲ 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
乙烯是工業上由化石碳源產生得，但植物和微生物會通過少數不尋常得酶反應產生少量得乙烯。利用氧同位素示蹤實驗和生化分析研究了一種微生物乙烯形成酶，以測試機理建議。
這種酶利用非血紅素鐵中心來激活氧氣，催化兩種不同機制得不同氧化反應。一種反應發生了偏離，結果是一種共底物精氨酸得碎裂。另一種反應可以將2-氧戊二酸完全裂解成乙烯、重碳酸鹽和兩個二氧化碳分子；然而，它偶爾會脫軌并產生一種omega -羥基產品。
▲ 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.
