Science,21JUN2024,VOL384,ISSUE6702《科学》2024年6月21日，第384卷，6702期?物理学PhysicsTopologicalHong-Ou-Mandelinterference拓扑Hong-Ou-Mandel干涉▲作者：MAXEHRHARDT,CHRISTOPHDITTEL,MATTHIASHEINRICHANDALEXANDERSZAMEIT▲链接：https://www.science.org/doi/10.1126/science.ado8192▲摘要：拓扑学和光学的相互作用为追求稳健的光子器件提供了一条途径，其在光子量子计算中的应用尚处于起步阶段。然而，通过光子的量子干涉，利用线性光学拓扑结构处理量子信息的可能性在很大程度上仍然未知。研究组提出了一种拓扑起源的Hong-Ou-Mandel干涉效应。结果表明，光子对的这种从相长到相消的干涉完全由合成磁通量决定，使其在基本水平上对误差具有弹性。该策略建立了一个量子化通量，仅促进相消量子干涉。该发现为受拓扑稳健量子门保护的下一代光子量子电路和可扩展量子计算的发展铺平了道路。▲Abstract：Theinterplayoftopologyandopticsprovidesaroutetopursuerobustphotonicdevices,withtheapplicationtophotonicquantumcomputationinitsinfancy.However,thepossibilitiesofharnessingtopologicalstructurestoprocessquantuminformationwithlinearoptics,throughthequantuminterferenceofphotons,remainlargelyuncharted.Here,wepresentaHong-Ou-Mandelinterferenceeffectoftopologicalorigin.Weshowthatthisinterferenceofphotonpairs—rangingfromconstructivetodestructive—issolelydeterminedbyasyntheticmagneticflux,renderingitresilienttoerrorsonafundamentallevel.Ourimplementationestablishesaquantizedfluxthatfacilitatesexclusivelydestructivequantuminterference.Ourfindingspavethewaytowardthedevelopmentofnext-generationphotonicquantumcircuitryandscalablequantumcomputingprotectedbyvirtueoftopologicallyrobustquantumgates.材料科学MaterialsScienceCarbonnanotubefiberswithdynamicstrengthupto14GPa动态强度高达14GPa的碳纳米管纤维▲作者：XINSHIZHANG,XUDONGLEI,XIANGZHENGJIA,TONGZHAOSUN,JIAJUNLUO,SHICHENXU,ETAL.▲链接：https://www.science.org/doi/10.1126/science.adj1082▲摘要：高动态强度对于在高应变率环境中使用的纤维材料至关重要。碳纳米管纤维是最有前景的候选纤维之一。采用优化分层结构的策略，研究组制备出动态强度为14GPa且能量吸收性能优异的碳纳米管纤维。纤维的动态性能归因于高应变率加载过程中单个纳米管的同时断裂和冲击能量的离域；这些行为则归因于界面相互作用、纳米管排列和致密化的改善。这项工作提出了一种在宏观尺度上利用单个碳纳米管强度的有效策略，并提供了新的机制见解。▲Abstract：Highdynamicstrengthisoffundamentalimportanceforfibrousmaterialsthatareusedinhigh–strainrateenvironments.Carbonnanotubefibersareoneofthemostpromisingcandidates.Usingastrategytooptimizehierarchicalstructures,wefabricatedcarbonnanotubefiberswithadynamicstrengthof14gigapascals(GPa)andexcellentenergyabsorption.Thedynamicperformanceofthefibersisattributedtothesimultaneousbreakageofindividualnanotubesanddelocalizationofimpactenergythatoccursduringthehigh–strainrateloadingprocess;thesebehaviorsareduetoimprovementsininterfacialinteractions,nanotubealignment,anddensificationtherein.Thisworkpresentsaneffectivestrategytoutilizethestrengthofindividualcarbonnanotubesatthemacroscaleandprovidesfreshmechanisminsights.Spintorque–drivenelectronparamagneticresonanceofasinglespininapentacenemolecule并五苯分子中单个自旋的自旋力矩驱动的电子顺磁共振▲作者：STEPANKOVARIK,RICHARDSCHLITZ,AISHWARYAVISHWAKARMA,DOMINICRUCKERT,PIETROGAMBARDELLAANDSEBASTIANSTEPANOW▲链接：https://www.science.org/doi/10.1126/science.adh4753▲摘要：对量子系统的调控通常由与时间相关的电场或磁场来实现。另外，电子自旋可通过自旋极化电流来控制。研究组演示了从扫描隧道显微镜尖端注入射频自旋极化电流至有机分子中的单个自旋相干驱动。在电子顺磁共振激发下，利用局域电流通过自旋力矩建立了单个自旋的动态控制。此外，该工作强调了自旋转移力矩的耗散作用，这与基于受控退相干操纵单个自旋的磁场非耗散作用迥然不同。▲Abstract：Controloverquantumsystemsistypicallyachievedbytime-dependentelectricormagneticfields.Alternatively,electronicspinscanbecontrolledbyspin-polarizedcurrents.Here,wedemonstratecoherentdrivingofasinglespinbyaradiofrequencyspin-polarizedcurrentinjectedfromthetipofascanningtunnelingmicroscopeintoanorganicmolecule.Withtheexcitationofelectronparamagneticresonance,weestablisheddynamiccontrolofsinglespinsbyspintorqueusingalocalelectriccurrent.Inaddition,ourworkhighlightsthedissipativeactionofthespin-transfertorque,incontrasttothenondissipativeactionofthemagneticfield,whichallowsforthemanipulationofindividualspinsbasedoncontrolleddecoherence.化学ChemistryWater-hydroxidetrappingincobalttungstateforprotonexchangemembranewaterelectrolysis钨酸钴中水-氢氧化物网络捕获助力质子交换膜水电解▲作者：RANITRAM,LUXIA,HINDBENZIDI,ANKUGUHA,VIKTORIAGOLOVANOVA,ALBAGARZóNMANJóN,ETAL.▲链接：https://www.science.org/doi/10.1126/science.adk9849▲摘要：析氧反应是高能效水基电解生产氢气和其他太阳能燃料的瓶颈。在质子交换膜水电解（PEMWE）中，贵金属通常是稳定催化该反应所必需的。在这项工作中，研究组报道了钨酸钴的分层通过稳定酸中晶格缺陷的氧化物和水—氢氧化物网络，实现了高活性和耐久性。所得到的催化剂具有较低的过电位，2V下的电流密度为1.8A/cm2，1.77V的工业条件下（80℃）在PEMWE系统中稳定运行时可高达1A/cm2；活性提高了三倍；在1A/cm2的电流密度下可稳定运行600小时。▲Abstract：Theoxygenevolutionreactionisthebottlenecktoenergy-efficientwater-basedelectrolysisfortheproductionofhydrogenandothersolarfuels.Inprotonexchangemembranewaterelectrolysis(PEMWE),preciousmetalshavegenerallybeennecessaryforthestablecatalysisofthisreaction.Inthiswork,wereportthatdelaminationofcobalttungstateenableshighactivityanddurabilitythroughthestabilizationofoxideandwater-hydroxidenetworksofthelatticedefectsinacid.Theresultingcatalystsachieveloweroverpotentials,acurrentdensityof1.8amperespersquarecentimeterat2volts,andstableoperationupto1amperepersquarecentimeterinaPEMWEsystematindustrialconditions(80°C)at1.77volts;athreefoldimprovementinactivity;andstableoperationat1amperepersquarecentimeteroverthecourseof600hours.地球科学EarthScienceTemperature-dependentemissionsdominateaerosolandozoneformationinLosAngeles温度依赖的排放主导着洛杉矶气溶胶和臭氧形成▲作者：EVAY.PFANNERSTILL,CALEBARATA,QINDANZHU,BENJAMINC.SCHULZE,RYANWARD,ROYWOODS,ETAL.▲链接：https://www.science.org/doi/10.1126/science.adg8204▲摘要：尽管交通排放量有所下降，但北美和欧洲城市仍面临着不健康的空气污染水平。这挑战了对其挥发性有机化合物（VOC）前体来源的传统理解。使用空气通量测量来绘制大范围VOC的排放图，研究组表明，生物萜类排放约占夏季洛杉矶排放的VOCOH反应活性、臭氧和二次有机气溶胶形成潜力的60%，并且该影响随着温度的升高而强烈增加。这意味着控制氮氧化物是减少洛杉矶臭氧形成的关键。研究组还表明，一些人为VOC排放量随着温度升高而增加，这是当前减排清单中未体现的变数。缓解空气污染的努力必须考虑到气候变暖将强烈改变排放量和排放成分。▲Abstract：Despitedeclinesintransportationemissions,urbanNorthAmericaandEuropestillfaceunhealthyairpollutionlevels.Thishaschallengedconventionalunderstandingofthesourcesoftheirvolatileorganiccompound(VOC)precursors.UsingairbornefluxmeasurementstomapemissionsofawiderangeofVOCs,wedemonstratethatbiogenicterpenoidemissionscontribute~60%ofemittedVOCOHreactivity,ozone,andsecondaryorganicaerosolformationpotentialinsummertimeLosAngelesandthatthiscontributionstronglyincreaseswithtemperature.ThisimpliesthatcontrolofnitrogenoxidesiskeytoreducingozoneformationinLosAngeles.WealsoshowsomeanthropogenicVOCemissionsincreasewithtemperature,whichisaneffectnotrepresentedincurrentinventories.Airpollutionmitigationeffortsmustconsiderthatclimatewarmingwillstronglychangeemissionamountsandcomposition.Bombradiocarbonevidenceforstrongglobalcarbonuptakeandturnoverinterrestrialvegetation全球陆地植被强大碳吸收和周转量的核弹放射性碳证据▲作者：HEATHERD.GRAVEN,HAMISHWARREN,HOLLYK.GIBBS,SAMARKHATIWALA,CHARLESKOVEN,JOANNALESTER,ETAL.▲链接：https://www.science.org/doi/10.1126/science.adl4443▲摘要：由于生产力和周转量产生的大量总碳交换存在约束很差的微小不平衡，植被和土壤吸收了大约30%的人为二氧化碳排放。研究组将20世纪60年代核弹试验产生的放射性碳的新预算与模型模拟相结合，以评估陆地植被的碳循环。结果发现，在耦合模式比对项目中使用的大多数最先进的植被模型都低估了植被生物量中的放射性碳积累。该发现结合对植被碳储量和生产力趋势的约束，表明目前净初级生产力可能至少为每年800亿吨碳，而当前模型预测的是每年430至760亿吨碳。人为碳在陆地植被中的储存可能比此前预测的更为短暂和脆弱。▲Abstract：Vegetationandsoilsaretakingupapproximately30%ofanthropogeniccarbondioxideemissionsbecauseofsmallimbalancesinlargegrosscarbonexchangesfromproductivityandturnoverthatarepoorlyconstrained.Wecombinedanewbudgetofradiocarbonproducedbynuclearbombtestinginthe1960swithmodelsimulationstoevaluatecarboncyclinginterrestrialvegetation.Wefoundthatmoststate-of-the-artvegetationmodelsusedintheCoupledModelIntercomparisonProjectunderestimatedtheradiocarbonaccumulationinvegetationbiomass.Ourfindings,combinedwithconstraintsonvegetationcarbonstocksandproductivitytrends,implythatnetprimaryproductivityislikelyatleast80petagramsofcarbonperyearpresently,comparedwiththe43to76petagramsperyearpredictedbycurrentmodels.Storageofanthropogeniccarboninterrestrialvegetationislikelymoreshort-livedandvulnerablethanpreviouslypredicted.澳门新葡萄新京6663·「中国」官方网站-2024App 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