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

光学增益以及损耗惹起的狄拉克品质

▲ 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

▲择要：

品质凡是被以为是物资的内涵属性，但现代物理学展现粒子品质有着繁杂的发源，例如高能物理学中的希格斯机制。于像石墨烯如许的晶格中，相对于论性狄拉克粒子可以以低能准粒子的情势存于，其品质是由晶格对于称破缺扰动付与的。这些孕育发生品质的机制都假设了厄米性，或者者说是能量守恒。

哄骗光子合成晶格，作者经由过程试验证实了基在光学增益以及损耗的非厄米微扰可以孕育发生狄拉克品质。他们切磋了增益以及丧失引诱狄拉克品质的时空项目怎样影响准粒子。研究注解，准粒子于空间界限处履历克莱因隧穿，但非厄米对于称的局部破缺可以于畴壁处孕育发生新的通量非守恒效应。

于狄拉克品质符号忽然翻转的时间界限上，研究者不雅察到时间反射征象的一种变体：于非相对于论性极限下，狄拉克准粒子的速率反转，而于相对于论性极限下，原始速率连结稳定。

▲ Abstract：

Mass is co妹妹only 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 sy妹妹etry-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 sy妹妹etry 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

▲择要：

伟大的系生手星绕着其主恒星运转，不太可能造成它们此刻的外形。相反，这些“热木星”行星被以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，包孕经由过程与第三个天体的角动量互换来引发偏疼，然后是潮汐驱动的轨道圆化。

极偏疼(e = 0.93)的巨型系生手星HD 80606 b的发明提供了不雅测证据，证实热木星多是经由过程这类高偏疼潮汐迁徙路径造成的。然而，还没有发明近似的热木星先人，模仿猜测影响这一机制有用性的一个要素是系生手星的品质，由于低品质的行星更有可能于近天通道时期被潮汐粉碎6。

研究者先容了对于TIC 241249530 b的光谱以及光度不雅测成果，这是一颗高品质的、轨道偏疼率e=0.94的温馨木星。TIC 241249530 b的轨道与离心振荡的汗青以及将来的潮汐圆化轨迹一致。研究对于变暖木星人口的品质以及偏疼率漫衍的阐发进一步展现了高品质以及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

▲择要：

科学、医学以及项目的前进依靠在成像方面的冲破，出格是于从集成电路或者哺乳植物年夜脑等功效体系获取多标准三维信息方面。实现这一方针凡是需要联合基在电子以及光子的要领。电子显微镜经由过程对于表层的持续粉碎性成像提供纳米级的分辩率，而X射线计较机体层摄影提供非粉碎性成像，而且近来于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，它降服了试验不不变性并实现了更高的机能，具备4纳米分辩率以及170倍的收罗速度，即每一秒14,000个分辩率元素。另外一项要害立异是层析成像反向流传重修技能，它可以或许对于比传统景深年夜10倍的样本举行成像。

经由过程联合这两项立异，研究者乐成地成像了一个开始进的(7纳米节点)贸易集成电路，其特色是由硅以及金属等低以及高密度质料制成的纳米布局，于选定的x射线波长下具备精良的辐射不变性以及对于比度。这些威力使患上对于芯片的设计以及打造举行具体的研究，直到单个晶体管的程度。

研究者估计，鄙人一代X射线源中，纳米分辩率以及更高X射线通量的联合将于从电子学到电化学以及神经科学等范畴孕育发生革命性的影响。

▲ 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 ma妹妹alian 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) co妹妹ercial 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

▲择要：

量子固体中的相关光驱动正于成为一个研究前沿，有很多有趣的非均衡量子相以及瞬态光致功效征象的报导，如铁电性、磁性以及超导性。于高温铜超导体中，某些声子模式的相关驱动致使了具备近似超导光学性子的瞬态，远远高在它们的改变温度Tc，而且贯串赝隙相。

然而，关在这类瞬态的微不雅性子和怎样将其与具备加强载流子迁徙率的非超导状况区别开来的问题仍旧存于。例如，今朝尚不清晰于这类时尚中驱动的铜是否体现出迈斯纳抗磁性。

研究者经由过程丈量放置于样品四周的磁光质料中的法拉第扭转来研究光驱动YBa2Cu3O6.48晶体周围的时间相干磁场。于恒定的外加磁场以及不异的驱动前提下，孕育发生近似超导的光学特征，不雅察到瞬态抗磁相应。

这类相应于尺寸上与具备相似外形以及尺寸的均衡型II超导体的相应相称，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长是不相容的。相反，它夸大了赝隙相的观点，此中初期的超导相干性被驱动器加强或者同步。

▲ 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

地下水依靠生态体系图展现了全世界旱地掩护需求

▲ 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

▲择要：

地下水是全世界最遍及的液态淡水来历，但它于撑持多种生态体系方面的作用却很少获得认可。然而，很多地域地下水依靠生态体系的位置以及规模尚不清晰，缺少响应的掩护办法。

作者以高分辩率(约莫30米)绘制了地下水依靠生态体系（GDE）图，发明它们存于在所阐发的全世界三分之一以上的旱地，包孕主要的全世界生物多样性热门地域。

于地下水耗竭率较低的以畜牧业为主导的景不雅中，GDE更为广泛以及持续，这注解很多GDE可能已经经因为水以及地盘哄骗体式格局而损失。然而，53%的GDE存于在地下水降落趋向的区域，这凸起注解火急需要掩护GDE免受地下水枯竭的威逼。

然而，研究者发明只要21%的GDE存于在受掩护的地盘或者具备可连续地下水治理政策的司法统领区，从而呼吁采纳步履掩护这些主要的生态体系。此外，研究了年夜萨赫勒地域GDE与文化以及社会经济要素的接洽，此中GDE于撑持生物多样性以及屯子生计方面阐扬着主要作用，以摸索政治不不变地域掩护GDE的其他手腕。

研究者暗示，GDE舆图为于差别之处、区域或者国际标准上优先思量以及制订政策以及掩护机制提供了要害信息，以掩护这些主要的生态体系以及依靠在它们的社会。

▲ 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总体平台

▲ 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

▲择要：

削减二氧化碳(CO2)排放火急需要年夜范围部署碳捕捉技能。这些技能必需从差别的来历分散二氧化碳，并将其运送到差别的汇。追求特定源汇对于的最好解决方案是一项繁杂的、触及多个好处攸关方的多方针应战，并取决在社会、经济以及区域配景。

今朝，研究遵照一个挨次的要领:化学家专一在质料设计，项目师专一在优化工艺，然后于影响经济以及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，凡是是末了的步调之一。

研究者先容了定制接收质料的工艺信息设计（PrISMa）平台，集成为了质料、工艺设计、技能经济以及生命周期评估。他们比力了全世界5个地域使用差别技能从差别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技能的成本效益、工艺配置以及位置，展现高机能吸附剂的份子特性，并提供有关情况影响、协同效益以及衡量的见解。经由过程于初期研究阶段结合好处相干者，PrISMa有助在加快碳捕集技能的成长，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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