编译 | 李言
Nature, 25 April 2024, Volume 628 Issue 8009
《自然》2024年4月25日，第628卷，8009期
天文学Astronomy
Stripped-envelope supernova light curves argue for central engine activity
利用剥离包层超新星的光曲线证实中心引擎的活动
▲ 作者：ósmar Rodríguez, Ehud Nakar & Dan Maoz
▲ 链接：
https://www.nature.com/articles/s41586-024-07262-x
▲ 摘要：
在此，我们分析了54个被充分观测到的剥离包层超新星样本的能量收支，并提出了统计上显著的、基本不受模型限制的观测证据，并证明了其中大多数（可能是全部）存在非放射性动力源。
我们考虑了可能导致这一结果的能量来源或者合理的系统误差，结论认为最合理的解释是存在一个长期的中心引擎，在爆炸后持续运行约103–106?秒。我们从观察结果中推断出引擎性能的限制因素。
例如，如果中心引擎是一颗磁化的中子星，那么初始磁场约为1015 G，初始旋转周期为1—100 ms，这表明剥离包层超新星可能是磁星形成的重要条件。
▲ Abstract：
Here we analyse the energy budget of a sample of 54 well-observed stripped-envelope supernovae of all sub-types and present statistically significant, largely model-independent, observational evidence for a non-radioactive power source in most of them (and possibly in all). We consider various energy sources, or alternatively, plausible systematic errors, that could drive this result, and conclude that the most likely option is the existence of a long-lived central engine, operating over ≈103–106?s after the explosion. We infer, from the observations, constraints on the engine properties. If, for example, the central engine is a magnetized neutron star, then the initial magnetic field is ≈1015?G and the initial rotation period is 1–100?ms, suggesting that stripped-envelope supernovae may constitute the formation events of the objects known as magnetars.
物理学Physics
One-dimensional proximity superconductivity in the quantum Hall regime
量子霍尔体系中的一维超导体
▲ 作者：Julien Barrier, Minsoo Kim et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07271-w
▲ 摘要：
在此，我们展示了最小扭曲双层石墨烯中的畴壁在量子霍尔体系中支持异常强大的邻近超导性，允许约瑟夫森结在接近超导电极的上临界场的运行。
我们发现临界电流是非振荡的，并且在整个量子化场范围内几乎不变，数值受限于驻留在畴壁内的严格一维电子通道的量子电导。该系统在量子化场中支持Andreev束缚态的能力是独一无二的，并为进一步探索提供了更多方向。
▲ Abstract：
Here we show that domain walls in minimally twisted bilayer graphene support exceptionally robust proximity superconductivity in the quantum Hall regime, allowing Josephson junctions to operate in fields close to the upper critical field of superconducting electrodes. The critical current is found to be non-oscillatory and practically unchanging over the entire range of quantizing fields, with its value being limited by the quantum conductance of ballistic, strictly one-dimensional, electronic channels residing within the domain walls. The system described is unique in its ability to support Andreev bound states at quantizing fields and offers many interesting directions for further exploration.
Optical clocks at sea
海上光学钟
▲ 作者：Jonathan D. Roslund, Arman Cing?z et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07225-2
▲ 摘要：
在此，我们报告在移动平台上运行的光学时钟的尺寸、性能和环境敏感性的组合发展。这个35 l时钟结合了分子碘光谱仪，光纤频率梳和调控电子设备。3个这样的时钟在太平洋的一所军舰上连续运行了20天，每天的计时误差在300皮秒以下。
这种时钟的性能与氢脉泽相当，但体积只有前者的十分之一。在海上操作高性能时钟具有挑战性，并且对导航至关重要。这次展示标志着一项重大的技术进步，预示着未来光学计时网络的到来。
▲ Abstract：
Here we report the development of optical clocks with the requisite combination of size, performance and environmental insensitivity for operation on mobile platforms. The 35?l clock combines a molecular iodine spectrometer, fibre frequency comb and control electronics. Three of these clocks operated continuously aboard a naval ship in the Pacific Ocean for 20 days while accruing timing errors below 300?ps per day. The clocks have comparable performance to active hydrogen masers in one-tenth the volume. Operating high-performance clocks at sea has been historically challenging and continues to be critical for navigation. This demonstration marks a significant technological advancement that heralds the arrival of future optical timekeeping networks.
材料科学Material Science
Graphene nanoribbons grown in hBN stacks for high-performance electronics
用于高性能电子器件的hBN堆叠中生长的石墨烯纳米带
▲ 作者：Bosai Lyu, Jiajun Chen et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07243-0
▲ 摘要：
在这里，我们报告高质量石墨烯纳米带（GNRs）在hBN堆叠中的无转移直接生长。生长的嵌入式GNRs具有超长(（高达0.25 mm）、超窄（小于5 nm）和具有之字形边缘的同手性等非常理想的特性。我们的原子模拟表明，嵌入生长的机制涉及在AA堆叠的hBN层之间滑动时GNR的超低摩擦。
利用生长的结构，我们展示了嵌入式GNR场效应器件的无转移制造，这一器件在室温下表现出优异性能，迁移率高达4,600 cm2?V–1?s–1，开关比高达106。
▲ Abstract：
Here we report the transfer-free direct growth of high-quality graphene nanoribbons (GNRs) in hBN stacks. The as-grown embedded GNRs exhibit highly desirable features being ultralong (up to 0.25?mm), ultranarrow (<5?nm) and homochiral with zigzag edges. Our atomistic simulations show that the mechanism underlying the embedded growth involves ultralow GNR friction when sliding between AA′-stacked hBN layers. Using the grown structures, we demonstrate the transfer-free fabrication of embedded GNR field-effect devices that exhibit excellent performance at room temperature with mobilities of up to 4,600?cm2?V–1?s–1 and on–off ratios of up to 106.
Digital colloid-enhanced Raman spectroscopy by single-molecule counting
单分子计数数字胶体增强拉曼光谱
▲ 作者：Xinyuan Bi, Daniel M. Czajkowsky, Zhifeng Shao & Jian Ye
▲ 链接：
https://www.nature.com/articles/s41586-024-07218-1
▲ 摘要：
在此，我们表明，使用数字（纳米）胶体增强拉曼光谱，可以通过单分子计数常规地在非常低浓度下实现广泛目标分子的可重复量化，仅受测量过程的泊松噪声的限制。
由于金属胶体纳米粒子（包括羟胺还原银胶体）增强这些振动特征，可以在常规条件下大规模制造，我们预计数字（纳米）胶体增强拉曼光谱将成为可靠和超灵敏检测包括对人类健康非常重要的各种分析物的首选技术。
▲ Abstract：
Here, as a proof of concept, we show that, using digital (nano)colloid-enhanced Raman spectroscopy, reproducible quantification of a broad range of target molecules at very low concentrations can be routinely achieved with single-molecule counting, limited only by the Poisson noise of the measurement process. As metallic colloidal nanoparticles that enhance these vibrational signatures, including hydroxylamine–reduced-silver colloids, can be fabricated at large scale under routine conditions, we anticipate that digital (nano)colloid-enhanced Raman spectroscopy will become the technology of choice for the reliable and ultrasensitive detection of various analytes, including those of great importance for human health.
生物学Biology
Hybrid speciation driven by multilocus introgression of ecological traits
由生态性状多点引入驱动的杂交物种形成
▲ 作者：Neil Rosser, Fernando Seixas et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07263-w
▲ 摘要：
在此，我们将种群基因组分析与物种特异性性状的数量性状位点定位相结合，研究了Heliconius蝴蝶杂交物种形成的案例。我们展示了Heliconius elevatus是一个与双亲同域的杂交物种，并且作为一个独立演化的品系持续存在了至少18万年。
尽管与其中一个亲本Heliconius pardalinus之间的基因流动普遍且持续，使它们基因组的 99% 都发生了同质化。剩下的1%遗传自另一个亲本Heliconius melpomene，广泛散布在H. elevatus的基因组中，形成了一个个与H. pardalinus不同的分化。
这些分化包含多种在破坏性选择下的特征，包括颜色模式、翅膀形状、寄主植物偏好、性信息素和配偶选择。总体来说，这些特征将H. elevatu置于自己的适应高峰，并允许与双亲共存。我们的研究结果表明，物种形成是由生态性状的引入驱动的，并且在多位点遗传结构下，基因流的物种形成是可能的。
▲ Abstract：
Here we combine population genomic analysis with quantitative trait locus mapping of species-specific traits to examine a case of hybrid speciation in Heliconius butterflies. We show that Heliconius elevatus is a hybrid species that is sympatric with both parents and has persisted as an independently evolving lineage for at least 180,000 years. This is despite pervasive and ongoing gene flow with one parent, Heliconius pardalinus, which homogenizes 99% of their genomes. The remaining 1% introgressed from the other parent, Heliconius melpomene, and is scattered widely across the H. elevatus genome in islands of divergence from H. pardalinus. These islands contain multiple traits that are under disruptive selection, including colour pattern, wing shape, host plant preference, sex pheromones and mate choice. Collectively, these traits place H. elevatus on its own adaptive peak and permit coexistence with both parents. Our results show that speciation was driven by introgression of ecological traits, and that speciation with gene flow is possible with a multilocus genetic architecture.
