米兰-《自然》（20240801出版）一周论文导读—新闻—科学网

Nature, Volume 632 Issue 8023, 1 August 2024

《天然》第632卷，8023期，2024年8月1日

Dirac mass induced by optical gain and loss

光学增益和消耗引发的狄拉克质量

▲ 作者：Letian Yu, Haoran Xue, Ruixiang Guo, Eng Aik Chan, Yun Yong Terh, Cesare Soci, Baile Zhang Y. D. Chong

▲链接：

https://www.nature.com/articles/s41586-024-07664-x

▲摘要：

质量凡是被认为是物资的内涵属性，但现代物理学揭露粒子质量有着复杂的发源，例如高能物理学中的希格斯机制。在像石墨烯如许的晶格中，相对论性狄拉克粒子可以以低能准粒子的情势存在，其质量是由晶格对称破缺扰动付与的。这些发生质量的机制都假定了厄米性，或说是能量守恒。

操纵光子合成晶格，作者经由过程尝试证实了基在光学增益和消耗的非厄米微扰可以发生狄拉克质量。他们切磋了增益和损掉引诱狄拉克质量的时空工程若何影响准粒子。研究注解，准粒子在空间鸿沟处履历克莱因隧穿，但非厄米对称的局部破缺可以在畴壁处发生新的通量非守恒效应。

在狄拉克质量符号忽然翻转的时候鸿沟上，研究者不雅察到时候反射现象的一种变体：在非相对论性极限下，狄拉克准粒子的速度反转，而在相对论性极限下，原始速度连结不变。

▲ Abstract：

Mass is commonly considered an intrinsic property of matter, but modern physics reveals particle masses to have complex origins1, such as the Higgs mechanism in high-energy physics. In crystal lattices such as graphene, relativistic Dirac particles can exist as low-energy quasiparticles with masses imparted by lattice symmetry-breaking perturbations. These mass-generating mechanisms all assume Hermiticity, or the conservation of energy in detail. Using a photonic synthetic lattice, we show experimentally that Dirac masses can be generated by means of non-Hermitian perturbations based on optical gain and loss. We then explore how the spacetime engineering of the gain and loss-induced Dirac mass affects the quasiparticles. As we show, the quasiparticles undergo Klein tunnelling at spatial boundaries, but a local breaking of a non-Hermitian symmetry can produce a new flux non-conservation effect at the domain walls. At a temporal boundary that abruptly flips the sign of the Dirac mass, we observe a variant of the time-reflection phenomenon: in the non-relativistic limit, the Dirac quasiparticle reverses its velocity, whereas in the relativistic limit, the original velocity is retained.

A hot-Jupiter progenitor on a super-eccentric retrograde orbit

超偏疼逆行轨道上的热木星祖星

▲ 作者：Arvind F. Gupta, Sarah C. Millholland, Haedam Im, Jiayin Dong, Jonathan M. Jackson, Ilaria Carleo, Jessica Libby-Roberts, Megan Delamer, Mark R. Giovinazzi, Andrea S. J. Lin, Shubham Kanodia, Xian-Yu Wang, Keivan Stassun, Thomas Masseron, Diana Dragomir, Suvrath Mahadevan, Jason Wright, Jaime A. Alvarado-Montes, Chad Bender, Cullen H. Blake, Douglas Caldwell, Caleb I. Ca?as, William D. Cochran, Paul Dalba, …Carl Ziegler Show authors

▲链接：

https://www.nature.com/articles/s41586-024-07688-3

▲摘要：

庞大的系外行星绕着其主恒星运行，不太可能构成它们此刻的外形。相反，这些“热木星”行星被认为是从冰线之外向内迁徙的，而且提出了几种可行的迁徙通道，包罗经由过程与第三个天体的角动量互换来激起偏疼，然后是潮汐驱动的轨道圆化。

极偏疼(e = 0.93)的巨型系外行星HD 80606 b的发现供给了不雅测证据，证实热木星多是经由过程这类高偏疼潮汐迁徙路径构成的。但是，还没有发现近似的热木星先人，摹拟猜测影响这一机制有用性的一个身分是系外行星的质量，由于低质量的行星更有可能在近天通道时代被潮汐粉碎6。

研究者介绍了对TIC 241249530 b的光谱和光度不雅测成果，这是一颗高质量的、轨道偏疼率e=0.94的暖和木星。TIC 241249530 b的轨道与离心振荡的汗青和将来的潮汐圆化轨迹一致。研究对变暖木星生齿的质量和偏疼率散布的阐发进一步揭露了高质量和高偏疼率之间的相干性。

▲ Abstract：

Giant exoplanets orbiting close to their host stars are unlikely to have formed in their present configurations1. These ‘hot Jupiter’ planets are instead thought to have migrated inward from beyond the ice line and several viable migration channels have been proposed, including eccentricity excitation through angular-momentum exchange with a third body followed by tidally driven orbital circularization. The discovery of the extremely eccentric (e?=?0.93) giant exoplanet HD?80606?b provided observational evidence that hot Jupiters may have formed through this high-eccentricity tidal-migration pathway. However, no similar hot-Jupiter progenitors have been found and simulations predict that one factor affecting the efficacy of this mechanism is exoplanet mass, as low-mass planets are more likely to be tidally disrupted during periastron passage6,7,8. Here we present spectroscopic and photometric observations of TIC?241249530?b, a high-mass, transiting warm Jupiter with an extreme orbital eccentricity of e?=?0.94. The orbit of TIC?241249530?b is consistent with a history of eccentricity oscillations and a future tidal circularization trajectory. Our analysis of the mass and eccentricity distributions of the transiting-warm-Jupiter population further reveals a correlation between high mass and high eccentricity.

High-performance 4-nm-resolution X-ray tomography using burst ptychography

高机能的纳米分辩率X射线断层扫描

▲ 作者：Tomas Aidukas, Nicholas W. Phillips, Ana Diaz, Emiliya Poghosyan, Elisabeth Müller, A. F. J. Levi, Gabriel Aeppli, Manuel Guizar-Sicairos Mirko Holler

▲链接：

https://www.nature.com/articles/s41586-024-07615-6

▲摘要：

科学、医学和工程的前进依靠在成像方面的冲破，特殊是在从集成电路或哺乳动物年夜脑等功能系统获得多标准三维信息方面。实现这一方针凡是需要连系基在电子和光子的方式。电子显微镜经由过程对表层的持续粉碎性成像供给纳米级的分辩率，而X射线计较机体层摄影供给非粉碎性成像，而且比来在小体积上实现了低至7纳米的分辩率。

作者实现了突发平面摄影，它降服了尝试不不变性并实现了更高的机能，具有4纳米分辩率和170倍的收集速度，即每秒14,000个分辩率元素。另外一项要害立异是层析成像反向传布重建手艺，它可以或许对照传统景深年夜10倍的样本进行成像。

经由过程连系这两项立异，研究者成功地成像了一个最早进的(7纳米节点)贸易集成电路，其特点是由硅和金属等低和高密度材料制成的纳米布局，在选定的x射线波长下具有杰出的辐射不变性和对照度。这些能力使得对芯片的设计和制造进行具体的研究，直到单个晶体管的程度。

研究者估计，鄙人一代X射线源中，纳米分辩率和更高X射线通量的连系将在从电子学到电化学和神经科学等范畴发生革命性的影响。

▲ Abstract：

Advances in science, medicine and engineering rely on breakthroughs in imaging, particularly for obtaining multiscale, three-dimensional information from functional systems such as integrated circuits or mammalian brains. Achieving this goal often requires combining electron- and photon-based approaches. Whereas electron microscopy provides nanometre resolution through serial, destructive imaging of surface layers1, ptychographic X-ray computed tomography offers non-destructive imaging and has recently achieved resolutions down to seven nanometres for a small volume. Here we implement burst ptychography, which overcomes experimental instabilities and enables much higher performance, with 4-nanometre resolution at a 170-times faster acquisition rate, namely, 14,000 resolution elements per second. Another key innovation is tomographic back-propagation reconstruction4, allowing us to image samples up to ten times larger than the conventional depth of field. By combining the two innovations, we successfully imaged a state-of-the-art (seven-nanometre node) commercial integrated circuit, featuring nanostructures made of low- and high-density materials such as silicon and metals, which offer good radiation stability and contrast at the selected X-ray wavelength. These capabilities enabled a detailed study of the chip’s design and manufacturing, down to the level of individual transistors. We anticipate that the combination of nanometre resolution and higher X-ray flux at next-generation X-ray sources will have a revolutionary impact in fields ranging from electronics to electrochemistry and neuroscience.

Magnetic field expulsion in optically driven YBa2Cu3O6.48

光驱动YBa2Cu3O6.48的磁场摈除

▲ 作者：S. Fava, G. De Vecchi, G. Jotzu, M. Buzzi, T. Gebert, Y. Liu, B. Keimer A. Cavalleri

▲链接：

https://www.nature.com/articles/s41586-024-07635-2

▲摘要：

量子固体中的相关光驱动正在成为一个研究前沿，有很多有趣的非均衡量子相和瞬态光致功能现象的报导，如铁电性、磁性和超导性。在高温铜超导体中，某些声子模式的相关驱动致使了具有近似超导光学性质的瞬态，远远高在它们的改变温度Tc，而且贯串赝隙相。

但是，关在这类瞬态的微不雅性质和若何将其与具有加强载流子迁徙率的非超导状况辨别开来的问题依然存在。例如，今朝尚不清晰在这类时尚中驱动的铜是不是表示出迈斯纳抗磁性。

研究者经由过程丈量放置在样品四周的磁光材猜中的法拉第扭转来研究光驱动YBa2Cu3O6.48晶体四周的时候相干磁场。在恒定的外加磁场和不异的驱动前提下，发生近似超导的光学特征，不雅察到瞬态抗磁响应。

这类响应在尺寸上与具有类似外形和尺寸的均衡型II超导体的响应相当，其体积磁化率χv为?0.3阶。这个值与光引诱的没有超导性的迁徙率增添是不相容的。相反，它强调了赝隙相的概念，此中初期的超导相干性被驱动器加强或同步。

▲ Abstract：

Coherent optical driving in quantum solids is emerging as a research frontier, with many reports of interesting non-equilibrium quantum phases and transient photo-induced functional phenomena such as ferroelectricity, magnetism and superconductivity. In high-temperature cuprate superconductors, coherent driving of certain phonon modes has resulted in a transient state with superconducting-like optical properties, observed far above their transition temperature Tc and throughout the pseudogap phase. However, questions remain on the microscopic nature of this transient state and how to distinguish it from a non-superconducting state with enhanced carrier mobility. For example, it is not known whether cuprates driven in this fashion exhibit Meissner diamagnetism. Here we examine the time-dependent magnetic field surrounding an optically driven YBa2Cu3O6.48 crystal by measuring Faraday rotation in a magneto-optic material placed in the vicinity of the sample. For a constant applied magnetic field and under the same driving conditions that result in superconducting-like optical properties, a transient diamagnetic response was observed. This response is comparable in size with that expected in an equilibrium type II superconductor of similar shape and size with a volume susceptibility χv of order ?0.3. This value is incompatible with a photo-induced increase in mobility without superconductivity. Rather, it underscores the notion of a pseudogap phase in which incipient superconducting correlations are enhanced or synchronized by the drive.

天气与生态 Climate Ecology

Groundwater-dependent ecosystem map exposes global dryland protection needs

地下水依靠生态系统图揭露了全球旱地庇护需求

▲ 作者：Melissa M. Rohde, Christine M. Albano, Xander Huggins, Kirk R. Klausmeyer, Charles Morton, Ali Sharman, Esha Zaveri, Laurel Saito, Zach Freed, Jeanette K. Howard, Nancy Job, Holly Richter, Kristina Toderich, Aude-Sophie Rodella, Tom Gleeson, Justin Huntington, Hrishikesh A. Chandanpurkar, Adam J. Purdy, James S. Famiglietti, Michael Bliss Singer, Dar A. Roberts, Kelly Caylor John C. Stella

▲链接：

https://www.nature.com/articles/s41586-024-07702-8

▲摘要：

地下水是全球最遍及的液态淡水来历，但它在撑持多种生态系统方面的感化却很少获得认可。但是，很多地域地下水依靠生态系统的位置和规模尚不清晰，缺少响应的庇护办法。

作者以高分辩率(年夜约30米)绘制了地下水依靠生态系统（GDE）图，发现它们存在在所阐发的全球三分之一以上的旱地，包罗主要的全球生物多样性热门地域。

在地下水耗竭率较低的以畜牧业为主导的景不雅中，GDE更加普遍和持续，这注解很多GDE可能已因为水和地盘操纵体例而损失。但是，53%的GDE存在在地下水降落趋向的区域，这凸起注解火急需要庇护GDE免受地下水枯竭的要挟。

但是，研究者发现只有21%的GDE存在在受庇护的地盘或具有可延续地下水治理政策的司法管辖区，从而呼吁采纳步履庇护这些主要的生态系统。另外，研究了年夜萨赫勒地域GDE与文化和社会经济身分的联系，此中GDE在撑持生物多样性和农村生计方面阐扬侧重要感化，以摸索政治不不变地域庇护GDE的其他手段。

研究者暗示，GDE地图为在分歧的处所、区域或国际标准上优先斟酌和制订政策和庇护机制供给了要害信息，以庇护这些主要的生态系统和依靠在它们的社会。

▲ Abstract：

Groundwater is the most ubiquitous source of liquid freshwater globally, yet its role in supporting diverse ecosystems is rarely acknowledged. However, the location and extent of groundwater-dependent ecosystems (GDEs) are unknown in many geographies, and protection measures are lacking. Here, we map GDEs at high-resolution (roughly 30?m) and find them present on more than one-third of global drylands analysed, including important global biodiversity hotspots. GDEs are more extensive and contiguous in landscapes dominated by pastoralism with lower rates of groundwater depletion, suggesting that many GDEs are likely to have already been lost due to water and land use practices. Nevertheless, 53% of GDEs exist within regions showing declining groundwater trends, which highlights the urgent need to protect GDEs from the threat of groundwater depletion. However, we found that only 21% of GDEs exist on protected lands or in jurisdictions with sustainable groundwater management policies, invoking a call to action to protect these vital ecosystems. Furthermore, we examine the linkage of GDEs with cultural and socio-economic factors in the Greater Sahel region, where GDEs play an essential role in supporting biodiversity and rural livelihoods, to explore other means for protection of GDEs in politically unstable regions. Our GDE map provides critical information for prioritizing and developing policies and protection mechanisms across various local, regional or international scales to safeguard these important ecosystems and the societies dependent on them.

A holistic platform for accelerating sorbent-based carbon capture

加快吸附剂碳捕捉的整体平台

▲ 作者：Charithea Charalambous, Elias Moubarak, Johannes Schilling, Eva Sanchez Fernandez, Jin-Yu Wang, Laura Herraiz, Fergus Mcilwaine, Shing Bo Peh, Matthew Garvin, Kevin Maik Jablonka, Seyed Mohamad Moosavi, Joren Van Herck, Aysu Yurdusen Ozturk, Alireza Pourghaderi, Ah-Young Song, Georges Mouchaham, Christian Serre, Jeffrey A. Reimer, André Bardow, Berend Smit Susana Garcia

▲链接：

https://www.nature.com/articles/s41586-024-07683-8

▲摘要：

削减二氧化碳(CO2)排放火急需要年夜范围摆设碳捕捉手艺。这些手艺必需从分歧的来历分手二氧化碳，并将其输送到分歧的汇。追求特定源汇对的最好解决方案是一项复杂的、触及多个好处攸关方的多方针挑战，并取决在社会、经济和区域布景。

今朝，研究遵守一个挨次的方式:化学家专注在材料设计，工程师专注在优化工艺，然后在影响经济和情况的范围长进行操作。评估这些影响，好比电厂生命周期内的温室气体排放，凡是是最后的步调之一。

研究者介绍了定制接收材料的工艺信息设计（PrISMa）平台，集成了材料、工艺设计、手艺经济和生命周期评估。他们比力了全球5个地域利用分歧手艺从分歧来历捕捉二氧化碳的60多个案例研究。

该平台同时向各好处相干者传递手艺的本钱效益、工艺设置装备摆设和位置，揭露高机能吸附剂的份子特点，并供给有关情况影响、协同效益和衡量的看法。经由过程在初期研究阶段结合好处相干者，PrISMa有助在加快碳捕集手艺的成长，鞭策实现净零排放的世界。

▲ Abstract：

Reducing carbon dioxide (CO2) emissions urgently requires the large-scale deployment of carbon-capture technologies. These technologies must separate CO2 from various sources and deliver it to different sinks. The quest for optimal solutions for specific source–sink pairs is a complex, multi-objective challenge involving multiple stakeholders and depends on social, economic and regional contexts. Currently, research follows a sequential approach: chemists focus on materials design and engineers on optimizing processes, which are then operated at a scale that impacts the economy and the environment. Assessing these impacts, such as the greenhouse gas emissions over the plant’s lifetime, is typically one of the final steps. Here we introduce the PrISMa (Process-Informed design of tailor-made Sorbent Materials) platform, which integrates materials, process design, techno-economics and life-cycle assessment. We compare more than 60 case studies capturing CO2 from various sources in 5 global regions using different technologies. The platform simultaneously informs various stakeholders about the cost-effectiveness of technologies, process configurations and locations, reveals the molecular characteristics of the top-performing sorbents, and provides insights on environmental impacts, co-benefits and trade-offs. By uniting stakeholders at an early research stage, PrISMa accelerates carbon-capture technology development during this critical period as we aim for a net-zero world.

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