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中国科学技术大学潘建伟、包小辉、张强等首次采用单光子干涉在独立存储节点间建立纠缠,并以此为基础构建了国际首个基于纠缠的城域三节点量子网络。该工作使得现实量子纠缠网络的距离由以往的几十米整整提升了三个数量级至几十公里,为后续开展盲量子计算、分布式量子计算、量子增强长基线干涉等量子网络应用奠定了科学与技术基础。相关研究成果于5月15日在线发表在国际学术期刊《自然》杂志上。通过量子态的远程传输来构建量子网络是大尺度量子信息处理的基本要素。基于量子网络,可以实现广域量子密钥分发以及分布式量子计算和量子传感,构成未来“量子互联网”的技术基础。目前,基于单光子传输的量子密钥网络已发展成熟,而面向分布式量子计算、分布式量子传感等进一步量子网络应用,需要采用量子中继技术在远距离量子存储器间构建量子纠缠,在此基础上通过广域量子隐形传态将各个量子信息处理节点连接起来。在量子隐形传态方面,中国科大潘建伟团队一直处于国际领先水平,先后实现了多终端[Nature 430,54(2004)]、多体[Nature Physics 2,678(2006)]以及多自由度[Nature 516,518(2015)]的量子隐形传态,为实现量子信息在量子网络中的传输途径奠定了技术基础。在量子存储与量子中继方面,研究团队长期开展了相关研究。团队在国际上率先实现了具有存储功能的稳定量子中继节点[Nature 454,1098(2008)];为提升存储寿命、读出效率、纠缠制备概率等关键指标,团队发展了三维光晶格冷原子量子存储、环形腔增强光与原子相互作用、里德堡阻塞抑制高阶激发等多项关键技术,不仅实现了综合性能最优的冷原子量子存储器[Nature Photonics 10,381(2016)],还实现了确定性的光与原子纠缠制备[Phys.Rev.Lett.128,060502(2022)]。在此基础上,研究团队近年来在量子存储网络方向取得多项重要进展。2019年,团队通过三光子干涉,实现了实验室内三个冷原子量子存储器间的纠缠,成为首个可拓展距离的量子网络原型[Nature Photonics 13,210(2019)]。2020年,团队利用量子频率转换技术将量子存储的出射光子波长由795纳米转换至1342纳米,并结合单光子锁相技术,成功实现了在实验室内经由50公里光纤连接的双节点纠缠[Nature 578,240(2020)]。为在远距离分离的独立量子存储器间建立纠缠,主要挑战在于如何控制单光子相位。基于单光子干涉的纠缠方案在纠缠速率方面有重大优势,然而实验难度非常高。纠缠过程中量子存储的控制激光、频率转换泵浦激光、长光纤信道等带来的细微相位抖动都会导致最终生成纠缠的退相干。为解决这一难题,团队设计并发展了一套非常精巧的相位控制方案:首先通过超稳腔稳频来压制控制激光线宽,其次通过光锁相环来构建读写激光间的相位关联,最后通过远程分时相位比对来构建两节点间的相位关联。采用以上相位控制技术,并利用量子频率转换,团队成功实现了相距十几千米远的量子存储器之间的纠缠。以此为基础,研究团队构建了国际上首个城域三节点量子纠缠网络。该网络可以在任意两个量子存储器节点间建立纠缠。 查看详细>>
来源:中国科学技术大学 点击量: 17099月17日,中国科学技术大学—紫金山天文台大视场巡天望远镜(即墨子巡天望远镜)正式启用,成功发布仙女座星系图片,标志着经过一个月左右的设备运行测试,望远镜设备基本达到设计标准,已经可以开展天文观测研究。仙女座星系(又称M31)是距离银河系最近和最大的旋涡星系,它的结构特点和金属丰度与银河系相近,是探索银河系及同类星系形成与演化的理想研究对象。由于仙女座星系在天空中跨度大,已有的天文望远镜观测仙女座星系费时费力,难以同时拍摄它的精准全貌及周围环境。墨子巡天望远镜兼具大视场和高分辨成像能力,首光获取了仙女座星系和其外围区域多色图像,揭示了仙女座星系及其周围天体的明亮至暗弱星光分布特征,可以用于细致刻画星系内部及星系间相互作用的动力学过程。首光图像利用了不同夜晚观测的150幅图像叠加而成,可以测定仙女座星系和其周围环境中的天体的亮度变化,开展时域天文学研究。此外,结合FAST射电观测数据,首光科学图像数据能够进一步揭示星系中恒星形成和气体之间的演化。墨子巡天望远镜是中国科学技术大学“双一流”学科平台建设项目,是中国科学技术大学和中国科学院紫金山天文台于2018年3月1日启动联合研制的大视场光学成像望远镜,2019年7月正式开展望远镜建设,2022年10月深空探测实验室开始参与望远镜建设,2023年8月望远镜建成并开展调试观测。墨子巡天望远镜是冷湖天文观测基地第一个投入运行并开展天文观测研究的大型设备。墨子巡天望远镜口径2.5米,采用国际先进的主焦光学系统设计和主镜主动光学矫正技术,可实现3度视场范围内均匀高像质和极低像场畸变成像,配备7.65亿像素大靶面主焦相机,具备大视场、高像质、宽波段的特点。墨子巡天望远镜通光面积大、杂散光少,系统探测灵敏度高,具备强大的巡天能力,能够每三个晚上巡测整个北天球一次,为北半球光学时域巡天能力最强设备。墨子巡天望远镜的建成,显著提升我国时域天文研究能力,使得我国时域天文观测能力达到国际先进水平。墨子巡天望远镜通过获取高精度位置和多波段亮度观测数据,可监测移动天体和光变天体,用于高效搜寻和监测天文动态事件,可以在高能时域天文(如引力波事件电磁对应体等)、太阳系天体普查(如寻找第九大行星)、银河系结构和近场宇宙学(如暗物质本质)等领域取得突破性原始创新成果。墨子巡天望远镜巡天数据叠加,将提供北天球最深的高精度、大天区、多色测光和位置星表,作为传世巡天数据,在未来数十年内可用于宇宙中各类天体的证认和系统研究。同时,墨子巡天望远镜将面向国家航天强国战略,开展太阳系近地天体等搜寻与监测研究,服务航天安全和深空探测战略需求。墨子巡天望远镜安置于青海省海西州茫崖市冷湖镇海拔4200米的赛什腾山天文台址,距离茫崖市冷湖镇区约70公里。冷湖赛什腾山天文台址年均晴夜数多、夜天光背景低、视宁度优良、空气中尘埃含量少,是国内近期发现的优秀光学天文观测台址。墨子巡天望远镜正式投入使用后,中国科学技术大学将进一步推动冷湖作为学校最重要的科研基地之一,联合中国科学院紫金山天文台等单位,加强科教深度融合,推动天文及相关学科的高水平科学研究和国际交流合作,培养天文及相关领域拔尖创新人才,带动青海吸引、汇聚和培养高端科技人才,提升科技创新能力,支持地方经济多元化发展。 查看详细>>
来源:中国科学技术大学 点击量: 801The space economy is growing rapidly,and countries are racing to build spaceports for launching satellites and rockets.However,these are complex and expensive projects to undertake at atime when technology and the economics of space are evolving quickly.New entrants will have to compete with strong incumbents,and many will operate for years before generating their target return on investment(ROI).For that reason,spaceport developers need to consider avariety of factors,including pricing,operations,and talent.Some of these factors are unique to individual facilities,while others apply to all spaceports.We have developed aframework for how to think through these factors,giving commercial and public-sector organizations astructured approach to building spaceports with the attributes required to survive and thrive amid increased competition.The next decade will reshape the competitive landscape for spaceports,but the fundamental principles of business will still apply.Facilities must effectively differentiate themselves,make acompelling case to their customers(launch service providers),and adopt asustainable financial model.To secure their future over the long term,spaceport developers need to choose the right path today.The Launch Market Is at an Inflection Point The number of space launches has risen steadily over the past two decades,with 186 total orbital launches worldwide in 2022,the highest number in asingle year.And more growth is coming.Low earth orbit(LEO)and medium earth orbit(MEO)satellites—which are less expensive and easier to launch than traditional geostationary orbit(GEO)satellites—are akey driver of this growth.They are being launched at arecord pace,often in constellations.The number of satellites launched has steadily increased over the past decade,increasing fivefold in the last five years alone.(See Exhibit 1.)Our analysis of industry data indicates that there will be at least 24,000 satellites launched from 2023 through 2030,and that figure could reach nearly 40,000 depending on the progress of planned megaconstellations in LEO.Space exploration is gathering pace as well,with 170 missions projected from 2022 through 2031,more than three times the number that launched in the past decade.The launch industry is growing nearly as fast,and capital is following.Although the market saw adip in overall investment activity in 2022—especially for startups—nearly 430 companies received some investment that year,and the ten largest deals accounted for$700 million in funding,an 18%increase over the amount in 2021.Amid the hundreds of startups emerging in the new space economy,the market remains characterized by ahandful of companies,such as SpaceX,that have strong positions.And these companies are rushing to secure capacity at capable spaceports.Spaceports,therefore,are alinchpin in the space economy and will help determine its growth trajectory.Many entities,in both the public and private sectors,are chasing the opportunity to build new spaceports,but there are constraints on how many can succeed.The Competitive Landscape for Spaceports Is Dynamic and Challenging Approximately 53 spaceports currently operate worldwide;most are located in China,Europe,Russia,and the US.Roughly 30 new sites have been proposed—including at least 20 that will support orbital launches.1 Many of the new spaceports are in countries that have not had alarge presence in space historically,such as Australia,Indonesia,and Peru.Governments often view spaceport development as ameans not only to boost the economy but also to achieve broader national objectives,such as establishing sovereignty in the increasingly important space domain.For this reason,new spaceport development will continue regardless of volatility in the launch market or investment climate.Yet the competition to secure customers will be fierce.New entrants will have to compete with strong incumbents and have the wherewithal to potentially operate for years before delivering hoped-for ROI. 查看详细>>
来源:波士顿咨询公司 点击量: 603The installation of Aurora’s 10,624th and final?“blade”marked amajor milestone for the highly anticipated“exascale”supercomputer at Argonne National Laboratory.After years of diligent work and planning,the system now contains all the hardware that will make it one of the most powerful supercomputers in the world when it is opened up for scientific research.Built by Intel and Hewlett Packard Enterprise,Aurora will be theoretically capable of delivering more than two exaflops of computing power,or more than 2billion billion calculations per second.These supercomputers are invaluable to scientists.“Everything we know about large-scale climate comes from climate simulations on supercomputers.What we know about the human genome comes from massive data analysis on big computers.Everything that’s happening in AI right now is happening on large-scale computers,”Rick Stevens,who helped lead the effort and is aprofessor with the University of Chicago and associate director at Argonne,told Chicago Magazine.“Our ability to design reactors,our ability to come up with new batteries — all that is aresult of computing.”The Aurora team has been building the system piece by piece over the last year and ahalf,installing blades and other components as they were delivered to Argonne,which is aU.S.Department of Energy national laboratory affiliated with the University of Chicago.“We have been living and breathing the Aurora installation since the first pieces were delivered in November of 2021,”said Susan Coghlan,project director for Aurora.?“While we still have alot of work to do before we can roll the system out to scientists worldwide,it is incredibly exciting to have the final hardware in place.”Blades are backbone of system As the backbone of the system,Aurora’s blades are sleek rectangular units that house its processors,memory,networking and cooling technologies.The machine gets its computational muscle from acombination of state-of-the-art Intel CPUs(central processing units)and GPUs(graphics processing units).Each blade is equipped with two Intel Xeon CPU Max Series processors and six Intel Data Center GPU Max Series processors.With each blade weighing in at around 70 pounds,the team needed aspecialized machine to delicately install the units vertically into Aurora’s refrigerator-sized racks.Each of the system’s 166 racks contains 64 blades.The racks are spread out across eight rows,occupying the space of two professional basketball courts in the ALCF data center.Expanded space to stretch out Before the system could be installed,Argonne had to carry out some major facility upgrades.This included adding new data center space to provide enough room for the supercomputer and building mechanical rooms and equipment to provide increased power and cooling capacity.Now that the machine is fully assembled,researchers will move their work to Aurora to begin scaling their applications on the full system.For the past few months they’ve been working on the Sunspot testbed,which is atest and development system that has the exact same architecture as Aurora but only on two racks.These early users help to stress-test the supercomputer and identify potential bugs that need to be resolved ahead of its deployment.“We’re looking forward to putting Aurora through its paces to make sure everything works as intended before we turn the system over to the broader scientific community,”Coghlan said. 查看详细>>
来源:芝加哥大学 点击量: 5266月23日,新华社“新华全媒头条”栏目推出重磅融媒报道《把“空间站”建在地球上——走进我国航天领域首个大科学装置》,“新华视频”栏目同步推出视频报道《我在地球造“空间站”》,多角度呈现由哈尔滨工业大学联合中国航天科技集团承建的空间环境地面模拟装置正式建设完成进入试运行阶段,诸多指标达到世界领先水平。团队成员多年来克服困难、自主创新、不断攻关,完成我国航天领域首个大科学装置、国际上首个综合环境因素最多、可实现多尺度和跨尺度环境效应研究的综合性研究装置,为我国航天事业发展及人类太空探索贡献智慧和力量。据了解,“新华全媒头条”是新华社重大报道精品栏目,旨在围绕重大主题、话题、热点新闻,打造体现新华社品格力量的重磅融媒报道。同时,《新华每日电讯》头版、新华网首页大图、新华社客户端头图都作了重点报道。圆梦:把“空间站”建到地球上空间环境严苛复杂,不仅航天器的可靠性受到考验,航天员的健康安全也面临挑战。如何增强宇宙探索能力,是亟待解决的难题。“要想飞得更远、驻得更久、探得更细,就要更加了解空间环境。”空间环境地面模拟装置常务副总指挥、哈尔滨工业大学空间环境与物质科学研究院院长李立毅说,“地面空间站”就是要在地球上建设一个与真实宇宙空间环境相似的基础科学研究平台,相当于把“空间站”建到地球上。“地面空间站”位于黑龙江省哈尔滨新区科技创新城,由哈尔滨工业大学联合中国航天科技集团承建。在建设园区,分布着“一大三小”四栋实验楼,“一大”即空间综合环境实验楼,“三小”即空间等离子体科学实验楼、空间磁环境科学实验楼和动物培养室。按照设计规划,“地面空间站”可以模拟真空、高低温、带电粒子、电磁辐射、空间粉尘、等离子体、弱磁场、中性气体、微重力等9大类空间环境因素,能够阐释空间环境对材料、器件、系统及生命体的影响规律和作用机制。相较于把实验仪器设备搬到太空,“地面空间站”既能节省成本、减少安全隐患,又可以根据科学问题和工程需要,设置特定的环境因素,不受时空限制进行多次重复验证,从而打造更加安全便捷的实验条件和科研手段。随着圆形拱门缓缓移动,月尘舱映入眼帘,这便是“模拟月球”实验舱。在一人多高的空间里,一米见方的平台闪着银光,悬置于顶部的探照灯和射线源造型各异。团队成员孙承月说,月尘舱攻克了多源辐照充电装备集成、微小粉尘均匀淋撒、强静电环境光学原位在线检测等多项关键技术,将为我国探月工程、月球基地建设和载人航天等重大航天工程提供科研平台。“未来,许多需要抵达太空才能进行的实验,在地面上就能完成。”哈尔滨工业大学空间环境与物质科学研究院副院长闫继宏说,这是科学家梦寐以求的。攻坚:把“冷板凳”坐热谈起“地面空间站”的缘起,李立毅说,空间环境导致航天故障频发,成为制约航天器长寿命和高可靠运行的关键所在。早在2005年,哈尔滨工业大学开始联合中国航天科技集团组建团队,就空间环境与物质相互作用基础科学问题的研究平台条件展开调研和分析。“科技攻关就是要奔着最紧迫的问题去。”哈尔滨工业大学空间环境与物质科学研究院副院长鄂鹏说,大科学装置建设对诸多基础前沿研究、战略高技术研究起着重要支撑作用。报道链接:https://h.xinhuaxmt.com/vh512/share/11562926?d=134b1df&channel=weixin 查看详细>>
来源:哈尔滨工业大学 点击量: 703A new spectrometer at the European XFEL’s small quantum systems(SQS)instrument will measure soft x-ray radiation and extreme ultraviolet(XUV)light generated by gaseous samples after interaction with intense XFEL pulses.This enables fresh avenues of research for the instrument.The spectrometer was built by acollaboration involving scientists from European XFEL and Uppsala University in Sweden,and will allow scientists at SQS to probe new and exciting processes on the atomic scale.“The spectrometer will give us the ability to look at XUV light emitted from atoms and molecules.Its unique capability to image along the interaction zone enables us to study the effect of European XFEL’s intense X-ray radiation as it travels through dense gases,”says Michael Meyer,leading scientist of the SQS instrument.“It will offer new possibilities to study fundamental processes in the interaction of x-ray radiation with matter.”Radiation with wavelengths in the extreme ultraviolet(XUV)range is emitted upon excitation or ionization of asample by the European XFEL pulses.Spectroscopy of these emitted XUV photons is an ideal tool for studying the quantum mechanical properties of the sample in its interaction with the intense X-ray pulses.This is particularly useful in comparison with other techniques based on electron or ion spectroscopy as the photons are not severely impacted by the charged particles created during the interaction.“At SQS we study fundamental properties of atomic and molecular systems,predominantly looking at electrons and ions.The new spectrometer complements these techniques and helps us to better understand physics on the very small scale,”says Thomas Baumann,scientist at SQS. 查看详细>>
来源:EuropeanXFEL 点击量: 549近日,国家自然科学基金委公布国家重大科研仪器研制项目(部门推荐)资助结果,上海交通大学齐飞教授牵头、联合中国科学院等单位申报的“基于超高帧频激光诊断的高温高压湍流燃烧研究装置”项目获得正式立项,资助直接经费8005.19万元。高温高压湍流燃烧在各类动力装置中发挥着重要的作用,当前先进燃烧技术的挑战是在向更高温度和压力条件发展的同时,实现更高的燃烧稳定性和更低的污染物排放。为应对这一重大挑战,亟需突破基于超高时空分辨的激光诊断技术,加强对湍流燃烧基础科学问题的研究。该项目面向国家需求和科学前沿,拟研制一套具有自主知识产权、基于超高帧频激光诊断的高温高压湍流燃烧研究装置,捕捉微秒/微米尺度火焰与流动结构的演变规律,在近真实工况下实现对燃烧流场、组分场、温度场的时间分辨三维多场同步测量,解析传统实验难以测得的高频、小尺度反应区,并揭示高温高压湍流条件下的化学反应机理及反应-流动耦合效应。该仪器装置将满足国内湍流燃烧研究需求,解锁复杂燃烧问题的“黑箱”,提升解决湍流燃烧难题的能力,为我国先进动力装备的研发提供理论指导和技术支撑。先进动力装备的发展离不开基础研究的突破,更离不开支撑基础研究的重大科研仪器的研制。依托该项目,学校将进一步打造我国标志性的、综合实验能力国际先进的湍流燃烧研究基地,推动我国高端动力装备领域的基础研究水平,产出世界一流的前沿科技成果。国家重大科研仪器研制项目面向科学前沿和国家需求,以科学目标为导向,资助对促进科学发展、探索自然规律和开拓研究领域具有重要作用的原创性科研仪器与核心部件的研制,以提升我国的原始创新能力。 查看详细>>
来源:上海交通大学 点击量: 763The University of Wisconsin–Madison Space Science and Engineering Center is providing fast turn-around satellite data to NASA as part of apush for timelier tracking and monitoring of wildfires.The“low-latency data”is sent within aminute of observation Aspecialized satellite ground station on the UW–Madison campus receives data,and SSEC Distinguished Scientist Liam Gumley is leading the program.“We’ve refined our ability to obtain data directly from the satellite and receive it on the ground,a process known as direct broadcast,”says Gumley.“Now,from Earth observation to wildfire detection is less than 60 seconds.”Four other ground stations across the U.S.also receive satellite data for wildfire monitoring.These low-latency data–information processed quickly to speed decision making–from U.S.Earth observation satellites are anew addition to the NASA Fire Information for Resource Management System.NASA developed FIRMS to provide satellite-based detections of active fires in the U.S.and Canada.Once afire is detected,NASA can coordinate with decision makers at other agencies to respond to and continuously monitor the fire and inform the public.An expert in satellite data,including algorithm development and real-time data receiving and processing,Gumley has been on the leading edge of efforts to get satellite-derived information to those who need it sooner. 查看详细>>
来源:威斯康辛大学麦迪逊分校 点击量: 863A university-industry collaboration has successfully run aquantum algorithm on atype of quantum computer known as acold atom quantum computer for the first time.The achievement by the team of scientists from the University of Wisconsin–Madison,ColdQuanta and Riverlane brings quantum computing one step closer to being used in real-world applications.Why it matters Practical quantum computers could solve complex problems,known as algorithms,that classical computers cannot.This could be beneficial for many applications,such as logistics,drug discovery and computational modeling of quantum processes.Running aquantum algorithm on the cold atom style of computer is aproof of concept that this approach could work.“There’s arace to build auseful quantum computer,and there’s ahandful of different approaches that are being developed to that end,”says Mark Saffman,a physics professor at UW–Madison,director of the Wisconsin Quantum Institute,and chief scientist for quantum information at ColdQuanta.“Cold atom qubits is one of the five approaches that are actively being developed,and this paper presents for the first time the capability of running quantum circuits and quantum algorithms using cold atom qubits.”The details The team,headed by Saffman,demonstrated two key achievements in astudy published April 20 in the journal Nature.Entangled up to six neutral atoms with long lifetimes.Previous neutral atom quantum computers have used atoms in ashorter-lived state.“One of the benefits[of our approach]is that it’s alonger-lived state,”says Trent Graham,a scientist at UW–Madison and lead author of the study.“We showed that we have coherence remaining in these states on the order of up to milliseconds,whereas in the[previously-demonstrated state],it decayed three to four hundred times faster.”Successfully ran two quantum algorithms on their quantum computer.The first,a quantum phase estimation algorithm,is acommon problem in chemistry that measures the molecular energy of an atom.The second is astrategy problem known as MaxCut,which has applications in logistics deployment and pattern recognition.One advantage of neutral atom qubits used in this approach is that they do not naturally interact with each other,so it is easier to control when they are“on”or“off.”The collaboration was key to the team’s success.The UW–Madison group conceived of and performed much of the work,ColdQuanta engineers in collaboration with the UW team designed and fabricated key subsystems of the quantum computer,and Riverlane staff contributed to circuit design,optimization and simulation.The catch?The quantum algorithms were very basic.But the work suggests that quantum computers that outcompete traditional ones are on the horizon.“These were very simple computations,but as you go to higher and higher circuit depth and more qubits,then it is actually possible to get to the regime where these problems can’t easily be calculated by classical computers,”Graham says.As is common with other classes of quantum computers,there is no error correction mechanism in place with this team’s computer. 查看详细>>
来源:威斯康辛大学麦迪逊分校 点击量: 925More than£15million has been awarded to UK institutions,including The University of Manchester,which are delivering the crucial software‘brain’of the world’s largest radio telescope.The Square Kilometre Array Observatory(SKAO)is set to explore the evolution of the early Universe and delve into the role of some the earliest processes in fashioning galaxies like our own Milky Way,among many other science goals.From its headquarters based at The University of Manchester’s Jodrell Bank Observatory in the UK,the SKAO will oversee the delivery and operations of two cutting-edge,complementary arrays with 197 radio telescope dishes located in South Africa and more than 130,000 low-frequency antennas in Western Australia.Professor Ben Stappers leads the Manchester team developing the Pulsar Search software.This programme will enable some of the most exciting SKAO experiments,testing General Relativity and aiming to detect Gravitational Waves.The University of Manchester will also lead the development of the software for the Monitor,Control and Calibration System of the SKA-LOW telescope.This telescope will be an array of over 130,000 antennas,which will,amongst other experiments,detect the very first stars to be born in the Universe. 查看详细>>
来源:曼彻斯特大学 点击量: 684