《自然》（20250327出版）一周论文导读

编译未玖

Nature, 27 March 2025, Volume 639, Issue 8056

《自然》2025年3月27日，第639卷，8056期

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天文学Astronomy

Witnessing the onset of reionization through Lyman-α emission at redshift 13

红移13处的莱曼-α发射见证再电离的开始

▲ 作者：Joris Witstok, Peter Jakobsen, Roberto Maiolino, Jakob M. Helton, Benjamin D. Johnson, Brant E. Robertson, et al.

▲链接：

https://www.nature.com/articles/s41586-025-08779-5

▲摘要：

宇宙再电离始于首批星系产生的紫外线（UV）辐射照亮充斥着原始宇宙的冷中性气体之时。詹姆斯·韦伯太空望远镜（JWST）的最新观测表明，在宇宙年龄不足3亿年时，就有惊人的紫外明亮星系存在于红移z=14之外的区域。

这些星系紫外线连续谱的平滑翻转被解释为中性氢跃迁的莱曼-α（Ly-α）阻尼翼吸收。然而，这些来源的关键特性（如其逃逸辐射场）在很大程度上仍难以捉摸。

研究组报告了来自JWST深空星系外观测（JADES）对一个红移z=13.0星系的光谱学观测结果，其呈现出一条独特的明亮发射线，明确被识别为Ly-α，以及一个平滑翻转。

他们观测到EWLy-α的等效宽度>40A（静止帧），此前仅在星系间介质电离程度较高的z<9区域普遍观测到。结合极蓝的紫外线连续谱，意外的Ly-α 发射表明该星系是大量产生和泄漏电离光子的源头。

这表明，大质量、炽热的恒星或活跃星系核创建了一个早期再电离区域，从而阻止了Ly-α线的完全消失，这为最早期星系的性质以及大爆炸后仅3.3亿年就已存在局部再电离区域提供了新见解。

▲ Abstract：

Cosmic reionization began when ultraviolet (UV) radiation produced in the first galaxies began illuminating the cold, neutral gas that filled the primordial Universe. Recent James Webb Space Telescope (JWST) observations have shown that surprisingly UV-bright galaxies were in place beyond redshift z?=?14, when the Universe was less than 300?Myr old. Smooth turnovers of their UV continua have been interpreted as damping-wing absorption of Lyman-α (Ly-α), the principal hydrogen transition. However, spectral signatures encoding crucial properties of these sources, such as their emergent radiation field, largely remain elusive. Here we report spectroscopy from the JWST Advanced Deep Extragalactic Survey (JADES) of a galaxy at redshift z?=?13.0 that reveals a singular, bright emission line unambiguously identified as Ly-α, as well as a smooth turnover. We observe an equivalent width of EWLy-α?>?40?? (rest frame), previously only seen at z?<?9 where the intervening intergalactic medium becomes increasingly ionized. Together with an extremely blue UV continuum, the unexpected Ly-α emission indicates that the galaxy is a prolific producer and leaker of ionizing photons. This suggests that massive, hot stars or an active galactic nucleus have created an early reionized region to prevent complete extinction of Ly-α, thus shedding new light on the nature of the earliest galaxies and the onset of reionization only 330?Myr after the Big Bang.

Vertical structure of an exoplanet’s atmospheric jet stream

系外行星大气急流的垂直结构

▲ 作者：Julia V. Seidel, Bibiana Prinoth, Lorenzo Pino, Leonardo A. dos Santos, Hritam Chakraborty, Vivien Parmentier, et al.

▲链接：

https://www.nature.com/articles/s41586-025-08664-1

▲摘要：

超热木星是一类极端系外行星，为研究大气过程提供了独特窗口。这类行星的昼/夜侧存在极端的温度差异，构成了一个基本的气候难题：能量是如何分布的？

为了解决这个问题，研究组必须观察这些大气的三维结构，尤其是其垂直环流模式，这些模式可作为先进全球环流模型的试验台。他们展示了超热木星大气环流的一个显著变化：从行星朝向炽热恒星一侧到朝向较冷太空一侧的纬向流动位于赤道超旋转急流下方。

通过解析大气动力学的垂直结构，研究组不再局限于大气的整体全球快照，能够更准确地识别流动模式，并实现与模型进行更细致的比较。基于第一性原理的全球环流模型难以复制观测到的环流模式，这凸显了对大气流动的理论理解与观测证据之间存在的关键差距。

这项工作可作为一个试验台，为下一代巨型望远镜的投入使用做好准备，以开发适用于太阳系之外天体的更全面模型。

▲ Abstract：

Ultra-hot Jupiters, an extreme class of planets not found in our Solar System, provide a unique window into atmospheric processes. The extreme temperature contrasts between their day and night sides pose a fundamental climate puzzle: how is energy distributed? To address this, we must observe the three-dimensional structure of these atmospheres, particularly their vertical circulation patterns that can serve as a testbed for advanced global circulation models, for example. Here we show a notable shift in atmospheric circulation in an ultra-hot Jupiter: a unilateral flow from the hot star-facing side to the cooler space-facing side of the planet sits below an equatorial super-rotational jet stream. By resolving the vertical structure of atmospheric dynamics, we move beyond integrated global snapshots of the atmosphere, enabling more accurate identification of flow patterns and allowing for a more nuanced comparison to models. Global circulation models based on first principles struggle to replicate the observed circulation pattern underscoring a critical gap between theoretical understanding of atmospheric flows and observational evidence. This work serves as a testbed to develop more comprehensive models applicable beyond our Solar System as we prepare for the next generation of giant telescopes.

物理学Physics

Hyperbolic phonon-polariton electroluminescence in 2D heterostructures

二维异质结构中的双曲声子-极化子电致发光

▲ 作者：Qiushi Guo, Iliya Esin, Cheng Li, Chen Chen, Guanyu Han, Song Liu, et al.

▲链接：

https://www.nature.com/articles/s41586-025-08686-9

▲摘要：

声子极化子是极性电介质中光子与光学声子相干耦合产生的准粒子。因其以低损耗将电场约束在深亚波长尺度内的特殊能力，声子极化子具有独特的优势，可以实现传统光子学无法实现的一系列应用，例如亚衍射成像和近场能量转移。

然而，通过光学方法激发声子极化子的传统方法涉及昂贵的光源和近场方案，并且由于声子极化子和自由空间光子之间的大量动量失配，通常导致激发效率低。

研究组证明了在适当的条件下，声子极化子可被非平衡态载流子全电激发。具体而言，在六方氮化硼（hBN）/石墨烯异质结构中，通过电驱动超高迁移率石墨烯中的载流子脱离平衡，他们在中红外频率下观察到hBN的双曲声子极化子（HPhPs）的明亮电致发光，其表现出与黑体热辐射不同的温度和载流子密度依赖性。

此外，HPhP电致发光光谱的载流子密度依赖性表明，HPhP电致发光可以由石墨烯中电荷载流子的带间跃迁和带内切伦科夫辐射引起。HPhP电致发光为实现电泵浦中红外和太赫兹声子极化子光源提供了途径。

▲ Abstract：

Phonon polaritons are quasiparticles resulting from the coherent coupling of photons with optical phonons in polar dielectrics. Owing to their exceptional ability to confine electric fields to deep-subwavelength scales with low loss, they are uniquely poised to enable a suite of applications beyond the reach of conventional photonics, such as subdiffraction imaging and near-field energy transfer. The conventional approach to exciting phonon polaritons through optical methods, however, involves costly light sources along with near-field schemes, and generally leads to low excitation efficiency owing to substantial momentum mismatch between phonon polaritons and free-space photons. Here we demonstrate that under proper conditions, phonon polaritons can be excited all-electrically by drifting charge carriers. Specifically, in hexagonal boron nitride (hBN)/graphene heterostructures, by electrically driving charge carriers in ultrahigh-mobility graphene out of equilibrium, we observe bright electroluminescence of hBN’s hyperbolic phonon polaritons (HPhPs) at mid-infrared frequencies, which shows a temperature and carrier density dependence distinct from black-body thermal emission. Moreover, the carrier density dependence of the HPhP electroluminescence spectra reveals that HPhP electroluminescence can arise from both interband transition and intraband Cherenkov radiation of charge carriers in graphene. The HPhP electroluminescence offers avenues for realizing electrically pumped mid-infrared and terahertz phonon-polariton light sources.

Down-converted photon pairs in a high-Q silicon nitride microresonator

高Q氮化硅微谐振器中的下转换光子对

▲ 作者：Bohan Li, Zhiquan Yuan, James Williams, Warren Jin, Adrian Beckert, Tian Xie, et al.

▲链接：

https://www.nature.com/articles/s41586-025-08662-3

▲摘要：

自发参量下转换（SPDC）产生的纠缠光子对是许多量子应用的核心。SPDC通常在具有固有二阶非线性（χ(2)）的非中心对称系统中进行。

研究组在Si3N4中展示了具有每秒80万对片上速率的强窄带SPDC。Si3N4是一种卓越的光子集成材料，并表现出最低的波导损耗（这对集成量子电路至关重要）。然而，由于氮化硅是无定形的，缺乏固有的χ(2)，这限制了其在光子量子器件中的作用。

研究组通过将高光学Q因子微腔内的强光场增强与光诱导空间电荷场相结合，在Si3N4中实现了SPDC。他们提出了具有高光谱亮度的窄带光子对。下转换光子对的量子性质通过符合测量验证。该光源基于Si3N4集成光子学技术，为片上量子系统开辟了新途径。

▲ Abstract：

Entangled photon pairs from spontaneous parametric down-conversion (SPDC) are central to many quantum applications. SPDC is typically performed in non-centrosymmetric systems with an inherent second-order nonlinearity (χ(2)). We demonstrate strong narrowband SPDC with an on-chip rate of 0.8 million pairs per second in Si3N4. Si3N4 is the pre-eminent material for photonic integration and also exhibits the lowest waveguide loss (which is essential for integrated quantum circuits). However, being amorphous, silicon nitride lacks an intrinsic χ(2), which limits its role in photonic quantum devices. We enabled SPDC in Si3N4 by combining strong light-field enhancement inside a high optical Q-factor microcavity with an optically induced space-charge field. We present narrowband photon pairs with a high spectral brightness. The quantum nature of the down-converted photon pairs is verified through coincidence measurements. This light source, based on Si3N4 integrated photonics technology, unlocks new avenues for quantum systems on a chip.

地球科学Earth Science

Record sea surface temperature jump in 2023–2024 unlikely but not unexpected

2023~2024年创纪录的海表温度跃升：不太可能，但并不意外

▲ 作者：Jens Terhaar, Friedrich A. Burger, Linus Vogt, Thomas L. Fr?licher Thomas F. Stocker

▲链接：

https://www.nature.com/articles/s41586-025-08674-z

▲摘要：

从2023年4月开始，全球海表温度在一年多的时间里处于创纪录水平，在2023年4月至2024年3月期间，平均比2015—2016年的记录高出0.25℃。这一事件的范围接近全球，强度前所未有，引发了人们的疑问：它有多罕见？气候模型是否能代表海表温度如此破纪录的跃升？

研究组构建了基于观测的合成时间序列，表明在当前长期变暖趋势下，全球海表温度的跃升至少打破了之前的记录0.25℃，这是512年一遇的事件（205年一遇至1185年一遇；95%置信区间）。如果没有全球变暖的趋势，这样的事件几乎不可能发生。

通过对各种全耦合气候模型进行270次模拟，研究组发现这些模型成功模拟了全球海表温度的破纪录跃升，从而支持了这些模型在理解此类事件的特征、驱动因素和后果方面的实用性。这些模型模拟表明，2023~2024年海表温度破纪录的跃升是一个极端事件，之后海表温度预计将恢复到预期的长期变暖趋势。

▲ Abstract：

Global ocean surface temperatures were at record levels for more than a year from April 2023 onwards, exceeding the previous record in 2015–2016 by 0.25?°C on average between April 2023 and March 2024. The nearly global extent and unprecedented intensity of this event prompted questions about how exceptional it was and whether climate models can represent such record-shattering jumps in surface ocean temperatures. Here we construct observation-based synthetic time series to show that a jump in global sea surface temperatures that breaks the previous record by at least 0.25?°C is a 1-in-512-year event under the current long-term warming trend (1-in-205-year to 1-in-1,185-year event; 95% confidence interval). Without a global warming trend, such an event would have been practically impossible. Using 270 simulations from a wide range of fully coupled climate models, we show that these models successfully simulate such record-shattering jumps in global ocean surface temperatures, underpinning the models’ usefulness in understanding the characteristics, drivers and consequences of such events. These model simulations suggest that the record-shattering jump in surface ocean temperatures in 2023–2024 was an extreme event after which surface ocean temperatures are expected to revert to the expected long-term warming trend.

Sliding and healing of frictional interfaces that appear stationary

表观静止摩擦界面的滑动和愈合

▲ 作者：Krittanon Sirorattanakul, Stacy Larochelle, Vito Rubino, Nadia Lapusta Ares J. Rosakis

▲链接：

https://www.nature.com/articles/s41586-025-08673-0

▲摘要：

摩擦界面存在于从生物关节到地震断层的各种系统中。这些界面何时以及如何滑动是地球科学和工程中的一个基本问题。人们认为存在一个阈值剪切力，称为静摩擦力，低于该阈值界面是静止的，尽管许多研究表明这一概念存在局限性。相比之下，速率和状态摩擦公式虽然预测界面总是处于滑动状态，但这一特征通常被认为是需要修正的理论假象。

研究组表明，受到恒定剪切和法向载荷的名义上静止界面正在滑动，其驱动力明显低于已知发生蠕变的经典定义的静摩擦，但速度越来越小，低至10-12ms-1。通过数字图像相关性，研究组可以直接在界面上进行精确测量。这种行为与经典的摩擦模型相矛盾，但证实了速率和状态摩擦的预测。

名义上静止界面的滑动率减小反映了界面的愈合，这将在随后的滑动事件（如地震和滑坡）中表现为更高的峰值摩擦，从而大大改变了其成核和传播，进而放大灾害规模。

▲ Abstract：

Frictional interfaces are found in systems ranging from biological joints to earthquake faults. When and how these interfaces slide is a fundamental problem in geosciences and engineering. It is believed that there exists a threshold shear force, called static friction, below which the interface is stationary, despite many studies suggesting that this concept is outdated. By contrast, rate-and-state friction formulations predict that interfaces are always sliding, but this feature is often considered an artefact that calls for modifications. Here we show that nominally stationary interfaces subjected to constant shear and normal loads, with a driving force that is notably below the classically defined static friction for which creep is known to occur, are sliding, but with diminishingly small rates down to 10-12 m s -1. Our precise measurements directly at the interface are enabled by digital image correlation. This behaviour contradicts classical models of friction but confirms the prediction of rate-and-state friction. The diminishing slip rates of nominally stationary interfaces reflect interface healing, which would manifest itself in higher peak friction in subsequent slip events, such as earthquakes and landslides, substantially modifying their nucleation and propagation and hence their hazard.