《自然》（20240425出版）一周論文導讀

編譯 | 李言

Nature, 25 April 2024, Volume 628 Issue 8009

《自然》2024年4月25日，第628卷，8009期

天文學Astronomy

Stripped-envelope supernova light curves argue for central engine activity

利用剝離包層超新星的光曲線證實中心引擎的活動

▲ 作者：ósmar Rodríguez, Ehud Nakar & Dan Maoz

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07262-x

▲ 摘要：

在此，我們分析了54個被充分觀測到的剝離包層超新星樣本的能量收支，并提出了統計上顯著的、基本不受模型限制的觀測證據，并證明了其中大多數（可能是全部）存在非放射性動力源。

我們考慮了可能導致這一結果的能量來源或者合理的系統誤差，結論認為最合理的解釋是存在一個長期的中心引擎，在爆炸后持續運行約103–106?秒。我們從觀察結果中推斷出引擎性能的限制因素。

例如，如果中心引擎是一顆磁化的中子星，那么初始磁場約為1015 G，初始旋轉周期為1—100 ms，這表明剝離包層超新星可能是磁星形成的重要條件。

▲ 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.

物理學Physics

One-dimensional proximity superconductivity in the quantum Hall regime

量子霍爾體系中的一維超導體

▲ 作者：Julien Barrier, Minsoo Kim et al.

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07271-w

▲ 摘要：

在此，我們展示了最小扭曲雙層石墨烯中的疇壁在量子霍爾體系中支持異常強大的鄰近超導性，允許約瑟夫森結在接近超導電極的上臨界場的運行。

我們發現臨界電流是非振蕩的，并且在整個量子化場范圍內幾乎不變，數值受限于駐留在疇壁內的嚴格一維電子通道的量子電導。該系統在量子化場中支持Andreev束縛態的能力是獨一無二的，并為進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

海上光學鐘

▲ 作者：Jonathan D. Roslund, Arman Cing?z et al.

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07225-2

▲ 摘要：

在此，我們報告在移動平臺上運行的光學時鐘的尺寸、性能和環境敏感性的組合發展。這個35 l時鐘結合了分子碘光譜儀，光纖頻率梳和調控電子設備。3個這樣的時鐘在太平洋的一所軍艦上連續運行了20天，每天的計時誤差在300皮秒以下。

這種時鐘的性能與氫脈澤相當，但體積只有前者的十分之一。在海上操作高性能時鐘具有挑戰性，并且對導航至關重要。這次展示標志著一項重大的技術進步，預示著未來光學計時網絡的到來。

▲ 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.

材料科學Material Science

Graphene nanoribbons grown in hBN stacks for high-performance electronics

用于高性能電子器件的hBN堆疊中生長的石墨烯納米帶

▲ 作者：Bosai Lyu, Jiajun Chen et al.

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07243-0

▲ 摘要：

在這里，我們報告高質量石墨烯納米帶（GNRs）在hBN堆疊中的無轉移直接生長。生長的嵌入式GNRs具有超長(（高達0.25 mm）、超窄（小于5 nm）和具有之字形邊緣的同手性等非常理想的特性。我們的原子模擬表明，嵌入生長的機制涉及在AA堆疊的hBN層之間滑動時GNR的超低摩擦。

利用生長的結構，我們展示了嵌入式GNR場效應器件的無轉移制造，這一器件在室溫下表現出優異性能，遷移率高達4,600 cm2?V–1?s–1，開關比高達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

單分子計數數字膠體增強拉曼光譜

▲ 作者：Xinyuan Bi, Daniel M. Czajkowsky, Zhifeng Shao & Jian Ye

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07218-1

▲ 摘要：

在此，我們表明，使用數字（納米）膠體增強拉曼光譜，可以通過單分子計數常規地在非常低濃度下實現廣泛目標分子的可重復量化，僅受測量過程的泊松噪聲的限制。

由于金屬膠體納米粒子（包括羥胺還原銀膠體）增強這些振動特征，可以在常規條件下大規模制造，我們預計數字（納米）膠體增強拉曼光譜將成為可靠和超靈敏檢測包括對人類健康非常重要的各種分析物的首選技術。

▲ 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.

生物學Biology

Hybrid speciation driven by multilocus introgression of ecological traits

由生態性狀多點引入驅動的雜交物種形成

▲ 作者：Neil Rosser, Fernando Seixas et al.

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07263-w

▲ 摘要：

在此，我們將種群基因組分析與物種特異性性狀的數量性狀位點定位相結合，研究了Heliconius蝴蝶雜交物種形成的案例。我們展示了Heliconius elevatus是一個與雙親同域的雜交物種，并且作為一個獨立演化的品系持續存在了至少18萬年。

盡管與其中一個親本Heliconius pardalinus之間的基因流動普遍且持續，使它們基因組的 99% 都發生了同質化。剩下的1%遺傳自另一個親本Heliconius melpomene，廣泛散布在H. elevatus的基因組中，形成了一個個與H. pardalinus不同的分化。

這些分化包含多種在破壞性選擇下的特征，包括顏色模式、翅膀形狀、寄主植物偏好、性信息素和配偶選擇。總體來說，這些特征將H. elevatu置于自己的適應高峰，并允許與雙親共存。我們的研究結果表明，物種形成是由生態性狀的引入驅動的，并且在多位點遺傳結構下，基因流的物種形成是可能的。

▲ 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.