物理学Physics Squeezing the quantum noise of a gravitational-wave detector below the standard quantum limit 将引力波探测器的量子噪声紧缩到尺度量子极限以下 ▲ 作者：WENXUAN JIA , VICTORIA XU , KEVIN KUNS, MASAYUKI NAKANO, LISA BARSOTTI, MATTHEW EVANS, NERGIS MAVALVALA, AND MEMBERS OF THE LIGO SCIENTIFIC COLLABORATION ▲链接： https://www.science.org/doi/10.1126/science.ado8069 ▲摘要： 引力波探测器利用数千米长的干与仪来丈量时空的细小膨胀和缩短。因为量子力学的缘由，这些丈量的精度是有限的。理论上，操纵光的紧缩态可以超出量子极限，而适合的滤光腔可以在更宽的频率规模内扩大这一优势。 Jia等人丈量了激光干与引力波天文台（LIGO）进级后的紧缩光和滤光腔系统的机能。研究证实，这些进级提高了探测器在宽频率规模内的活络度。在一个较小的规模内，它超出了量子极限。 ▲ Abstract： Gravitational wave detectors use kilometers-long interferometers to measure tiny expansions and contractions of spacetime. The precision of th开云体育appose measurements is limited due to quantum mechanics. Theoretically, that quantum limit could be surpassed by using squeezed states of light, and a suitable filter cavity could extend the advantage over a wide frequency range. Jia et al. measured the performance of the Laser Interferometer Gravitational-Wave Observatory (LIGO) after it was upgraded with a squeezed light and filter cavity system. The authors demonstrate that the upgrades improved the sensitivity of the detector over a wide range of frequencies. Over a smaller range, it surpassed the quantum limit. Origin and fate of the pseudogap in the doped Hubbard model 搀杂哈伯德模子中赝隙的发源和命运 ▲ 作者：FEDOR IMKOVIC IV, RICCARDO ROSSI, ANTOINE GEORGES, AND MICHEL FERRERO ▲链接： https://www.science.org/doi/10.1126/science.ade9194 ▲摘要： 虽然它很简约，哈伯德模子却能描写一些强相干物资的实例，但仍有一些在数值上难以解决的问题，将零温度和有限温度下的成果联系起来特别辣手。 Simkovic等人利用图解蒙特卡罗计较来查抄在有限温度下搀杂哈伯德模子中赝隙相的外不雅。发现该相与反铁磁自旋相干紧密亲密相干，并与零温度下计较的基态条纹相相连。 ▲ Abstract： Despite its simplicity, the Hubbard model may be capable of describing some instances of strongly correlated matter. However, this remains difficult to solve numerically; connecting the results at zero and finite temperatures is particularly tricky. Simkovic et al. used diagrammatic Monte Carlo calculations to examine the appearance of the pseudogap phase in the doped Hubbard model at finite temperatures. This phase was found to be closely associated with antiferromagnetic spin correlations and to connect to the ground-state stripe phase calculated at zero temperature. 化学Chemistry Polyolefin waste to light olefins with ethylene and base-metal heterogeneous catalysts 用乙烯和贱金属非均相催化剂将废旧聚烯烃转化为轻烯烃 ▲ 作者：RICHARD J. CONK, JULES F. STAHLER, JAKE X. SHI, JI YANG, NATALIE G. LEFTON, JOHN N. BRUNN, ALEXIS T. BELL, AND JOHN F. HARTWIG ▲链接： https://www.science.org/doi/10.1126/science.adq7316 ▲摘要： 原则上，将塑料分化成其原始构件是一种抱负的收受接管策略。但在实践中，这类方式不成能用在今朝利用的两种最多见的塑料 聚乙烯和聚丙烯。由于相干反映在能耗上不占优势。比来，几组研究人员注解，用适合的催化剂引入新颖的乙烯可以将聚烯烃转化为丙烯，但用在催化的贵金属价钱太高。 此刻Conk等人发现，可以在这个进程中利用地球上更丰硕的氧化钨和钠的组合。研究注解，氧化钨在二氧化硅上和钠在 -氧化铝上的简单组合将聚乙烯和聚丙烯或二者的夹杂物转化为丙烯或丙烯和异丁烯的夹杂物，在320 C下产量年夜在90%，而不需要对肇端聚烯烃进行脱氢。 ▲ Abstract： Breaking down plastic into its original building blocks is an ideal recycling strategy in principle. Unfortunately, in practice, this approach isn t possible for the two most common plastics currently in use, polyethylene and polypropylene, because the reaction is too energetically unfavorable. Very recently, several groups of researchers showed that introducing fresh ethylene with the right catalyst can transform polyolefins into propylene, but the precious metals used for the catalysis are prohibitively expensive. Conk et al. now report that the process works using a more Earth-abundant combination of tungsten oxide and sodium. The research shows that the simple combination of tungsten oxide on silica and sodium on gamma-alumina transforms PE, PP, or a mixture of the two, including postconsumer forms of these materials, to propylene or a mixture of propylene and isobutylene in greater than 90% yield at 320 C without the need for dehydrogenation of the starting polyolefins. Radical-mediated click-clip reactions 介导的点击反映 ▲ 作者：JIANTAO ZHAO, HUACHENG YU, XINGCHEN JIN, BO QIN,SHAN MEI, JIANG-FEI XU,XI ZHANG ▲链接： https://www.science.org/doi/10.1126/science.adn2259 ▲摘要： 点击化学是指在暖和前提下快速进行高转化的偶联反映，同时避免竞争路子，发生相对较少的华侈。这类手艺的首要错误谬误是，这些有益性质背后的壮大驱动力常常会禁止可逆性。 Zhao等人报导了胺和吩噻嗪之间的氧化偶联在室温下表示出近似点击的效力。但是，在近紫外照耀下，发生的硫-氮键可以以类似的效力进行还原性裂解。 ▲ Abstract： Click chemistry refers to a growing class of coupling reactions that proceed rapidly to high conversion under mild conditions while avoiding competing pathways and generating relatively little waste. The main drawback to this technique is that the strong driving force underlying these favorable properties tends to prevent reversibility. Zhao et al. report an oxidative coupling between amines and phenothiazines that manifests click-like efficiency at room temperature. However, the resulting sulfur-nitrogen bond can be reductively cleaved with similar efficiency by irradiation in the near-ultraviolet range. 地球科学Geoscience A 485-million-year history of Earth s surface temperature 4.85亿年汗青的地球概况温度 ▲ 作者：EMILY J. JUDD, JESSICA E. TIERNEY, DANIEL J. LUNT, ISABEL P. MONTAEZ, BRIAN T. HUBER, SCOTT L. WING, AND PAUL J. VALDES ▲链接 https://www.science.org/doi/10.1126/science.adk3705 ▲摘要： 在曩昔的5亿年里，动植物的进化模式对天气的演化发生了主要影响。领会这一期间全球平均地表温度（GMST）是若何转变的，对理解这段时候内驱动天气的进程相当主要。 Judd等人提出了将代办署理数据与天气摹拟相连系构建的曩昔4.85亿年的GMST记实。他们发现，全球平均地表温度在11℃到36℃的规模内转变， 表不雅 天气敏感性为~8℃，年夜约是今天的两到三倍。 ▲ Abstract： Understanding how global mean surface temperature (GMST) has varied over the past half-billion years, a time in which evolutionary patterns of flora and fauna have had such an important influence on the evolution of climate, is essential for understanding the processes driving climate over that interval. Judd et al. present a record of GMST over the past 485 million years that they constructed by combining proxy data with climate modeling. They found that GMST varied over a range from 11 C to 36 C, with an apparent climate sensitivity of ～8 C, about two to three times what it is today. Atmospheric blocking slows ocean-driven melting of Greenland s largest glacier tongue 年夜气梗阻减缓格陵兰岛最年夜冰川舌的熔化 ▲ 作者：REBECCA ADAM MCPHERSON, CLAUDIA WEKERLE, TORSTEN KANZOW, MONICA IONITA, FINN OLE HEUKAMP, OLE ZEISING, AND ANGELIKA HUMBERT ▲链接： https://www.science.org/doi/10.1126/science.ado5008 ▲摘要： 最近几年来，格陵兰岛的冰川正在加快流掉。McPherson等人发现，流入海洋的79号北冰川的熔化最近几年来有所减缓。在冰排放地址的不雅测显示，从2018年到2021年，冰舌以下的水温有所降落。 海洋热输送的削减归因在北欧海四周海洋环流的减和缓年夜西洋中心水的冷却。这类减速是由欧洲年夜气梗阻致使的，冷空气经由过程弗拉姆海峡进入北极。 ▲ Abstract： Greenland has been experiencing accelerating glacier mass loss in recent years. McPherson et al. have found that melting of the 79 North Glacier, which discharges into the ocean, has been slowed somewhat in recent years. Observations at the site of ice discharge show that from 2018 to 2021, water temperatures below the ice tongue cooled. The reduction in ocean heat transport was attributed to a slowdown in ocean circulation around the Nordic seas and a cooling of the Atlantic Intermediate Water. 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