Nature, 19 May 2022, Volume 605 Issue 7910
《自然》2022年5月19日，第605卷，7910期
物理学Physics
Microcomb-driven silicon photonic systems
微腔光梳驱动的硅光子系统
作者：Haowen Shu, Lin Chang, Yuansheng Tao, Bitao Shen, Weiqiang Xie, Ming Jin, Andrew Netherton, Zihan Tao, Xuguang Zhang, Ruixuan Chen, Bowen Bai, Jun Qin, Shaohua Yu, Xingjun Wang & John E. Bowers
链接：
https://www.nature.com/articles/s41586-022-04579-3
摘要：
在此，我们使用一种节能且操作简单的铝-镓-砷-绝缘体微梳源将两种技术结合起来，来驱动互补金属氧化物-半导体硅基光电子片。我们分别展示了用于光数据传输和微波光子学的两种重要的芯片级光子系统。
我们展示了一种基于微腔光梳的集成光子数据链路，基于脉冲振幅四电平调制方案，以每秒2太比特的聚合速率，并使用时间拉伸方法构造了具有高集成水平的高可重构微波光子滤波器。这种微腔光梳和硅基光电子片集成组件的协同作用是迈向下一代完全集成光子系统的重要一步。
Abstract：
Here we combine these two technologies by using a power-efficient and operationally simple aluminium-gallium-arsenide-on-insulator microcomb source to drive complementary metal–oxide–semiconductor SiPh engines. We present two important chip-scale photonic systems for optical data transmission and microwave photonics, respectively. A microcomb-based integrated photonic data link is demonstrated, based on a pulse-amplitude four-level modulation scheme with a two-terabit-per-second aggregate rate, and a highly reconfigurable microwave photonic filter with a high level of integration is constructed using a time-stretch approach. Such synergy of a microcomb and SiPh integrated components is an essential step towards the next generation of fully integrated photonic systems.
Observation of a molecular bond between ions and Rydberg atoms
离子和里德堡原子之间的分子键
作者：Nicolas Zuber, Viraatt S. V. Anasuri, Moritz Berngruber, Yi-Quan Zou, Florian Meinert, Robert L?w & Tilman Pfau
链接：
https://www.nature.com/articles/s41586-022-04577-5
摘要：
在此，基于离子电荷与键长为几微米的里德堡原子的翻转诱导偶极子之间的相互作用，我们观察到一种新型的分子离子。我们测量振动谱，并利用高分辨率离子显微镜在空间上解析分子的键长和角对齐。由于键长较大，分子动力学非常缓慢。这些结果为分子动力学时空效应的未来研究铺平了道路。
Abstract：
Here we observe a new type of molecular ion based on the interaction between the ionic charge and a flipping-induced dipole of a Rydberg atom with a bond length of several micrometres. We measure the vibrational spectrum and spatially resolve the bond length and the angular alignment of the molecule using a high-resolution ion microscope. As a consequence of the large bond length, the molecular dynamics is extremely slow. These results pave the way for future studies of spatio-temporal effects in molecular dynamics (for example, beyond Born–Oppenheimer physics).
Direct observation of the dead-cone effect in quantum chromodynamics
量子色动力学中的死角效应
作者：ALICE Collaboration
链接：
https://www.nature.com/articles/s41586-022-04572-w
摘要：
在粒子对撞机实验中，具有大动量转移的基本粒子相互作用产生夸克和胶子（称为部分子）。正如量子色动力学（QCD）理论所描述的那样，它们的演化受强作用力控制。以前，由于从实验可及的强子中重建级联夸克和胶子的挑战，直接观察QCD中的死角效应是不可能的。
我们报告用新的迭代聚类技术重建粲夸克的部分子簇的QCD死角的直接观测。这一结果证实了QCD的一个基本特征。此外，死角角度的测量构成了对粒子物理标准模型中的基本常数——粲夸克非零质量的直接实验观测。
Abstract：
In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD). Previously, a direct observation of the dead-cone effect in QCD had not been possible, owing to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible hadrons. We report the direct observation of the QCD dead cone by using new iterative declustering techniques to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD. Furthermore, the measurement of a dead-cone angle constitutes a direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics.
Polariton Bose–Einstein condensate from a bound state in the continuum
连续谱束缚态中的极化激元玻色-爱因斯坦凝聚物
作者：V. Ardizzone, F. Riminucci, S. Zanotti, A. Gianfrate, M. Efthymiou-Tsironi, D. G. Suàrez-Forero, F. Todisco, M. De Giorgi, D. Trypogeorgos, G. Gigli, K. Baldwin, L. Pfeiffer, D. Ballarini, H. S. Nguyen, D. Gerace & D. Sanvitto
链接：
https://www.nature.com/articles/s41586-022-04583-7
摘要：
在此，我们展示了在连续谱束缚态（BIC）中发生的非平衡玻色-爱因斯坦凝聚-混合光物质激发，这是由于其特殊的非辐射性质，有利于极化子的积累。超长BIC寿命和波导几何结构的紧密约束相结合，能够实现极低的冷凝阈值密度，这不是在色散最小值中达到的，而是在倒数空间中的鞍点达到的。
通过连接玻色子凝聚和对称保护辐射本征模，我们揭示了将拓扑性质传递到具有未探索色散特性的宏观量子态的方法。这一发现可能为低成本集成器件的节能极化子凝聚开辟道路，最终适合于开发混合光物质光学电路。
Abstract：
Here we show non-equilibrium Bose–Einstein condensation of polaritons—hybrid light–matter excitations—occurring in a BIC thanks to its peculiar non-radiative nature, which favours polariton accumulation. The combination of the ultralong BIC lifetime and the tight confinement of the waveguide geometry enables the achievement of an extremely low threshold density for condensation, which is reached not in the dispersion minimum but at a saddle point in reciprocal space. By bridging bosonic condensation and symmetry-protected radiation eigenmodes, we reveal ways of imparting topological properties onto macroscopic quantum states with unexplored dispersion features. Such an observation may open a route towards energy-efficient polariton condensation in cost-effective integrated devices, ultimately suited for the development of hybrid light–matter optical circuits.
天文学Astronomy
A trail of dark-matter-free galaxies from a bullet-dwarf collision
矮星撞击后形成的无暗物质星系的轨迹
作者：Pieter van Dokkum, Zili Shen, Michael A. Keim, Sebastian Trujillo-Gomez, Shany Danieli, Dhruba Dutta Chowdhury, Roberto Abraham, Charlie Conroy, J. M. Diederik Kruijssen, Daisuke Nagai & Aaron Romanowsky
链接：
https://www.nature.com/articles/s41586-022-04665-6
摘要：
在此，我们展示了现在DF2和DF4的视距和径向速度与它们在大约80亿年前的一次矮星撞击后形成的是一致的。此外，我们发现DF2和DF4是7到11个低光度大物体的线性子结构的一部分。
我们认为，这些都起源于同一事件，形成的这条无暗物质星系的轨迹超过2百万秒差距长，与视线的角度为7°±2°。我们还初步确认了两个始祖星系的高暗物质含量残留物，它们被认为位于彗尾的前沿。
Abstract：
Here we show that the present-day line-of-sight distances and radial velocities of DF2 and DF4 are consistent with their joint formation in the aftermath of a single bullet-dwarf collision, around eight billion years ago. Moreover, we find that DF2 and DF4 are part of an apparent linear substructure of seven to eleven large, low-luminosity objects. We propose that these all originated in the same event, forming a trail of dark-matter-free galaxies that is roughly more than two?megaparsecs long and angled 7°±2° from the line of sight. We also tentatively identify the highly dark-matter-dominated remnants of the two progenitor galaxies that are expected at the leading edges of the trail.
地球科学Earth Science
Expanding ocean food production under climate change
在气候变化的背景下增大海洋粮食生产量
作者：Christopher M. Free, Reniel B. Cabral, Halley E. Froehlich, Willow Battista, Elena Ojea, Erin O’Reilly, James E. Palardy, Jorge García Molinos, Katherine J. Siegel, Ragnar Arnason, Marie Antonette Juinio-Me?ez, Katharina Fabricius, Carol Turley & Steven D. Gaines
链接：
https://www.nature.com/articles/s41586-022-04674-5
摘要：
在此，我们调查了在气候变化下，渔业和海水养殖的协调改变是否能够增加人均海产品产量。我们发现，适应气候变化的渔业改革是必要的，但即使大幅减少温室气体排放，这也不足以维持全球人均海产品产量。
然而，可持续海水养殖提高人均海产品产量的潜力十分巨大——在除最严重排放情景外的所有情况下都可能提高人均海产品产量。这些增长能否实现，有赖于渔业改革、饲料技术的持续进步以及建立有效的海水养殖管理和高效实践。
此外，大幅遏制碳排放对于减少不平等、提高改革效率和降低我们分析中没有考虑到的风险至关重要。尽管气候变化将挑战海洋满足日益增长的粮食需求的能力，但通过迅速采取有效行动减少排放、改革捕捞渔业和扩大可持续的海水养殖业务，海洋可以生产比目前更多的食物。
Abstract：
Here we investigated whether coordinated reforms in fisheries and mariculture could increase seafood production per capita under climate change. We find that climate-adaptive fisheries reforms will be necessary but insufficient to maintain global seafood production per capita, even with aggressive reductions in greenhouse-gas emissions. However, the potential for sustainable mariculture to increase seafood per capita is vast and could increase seafood production per capita under all but the most severe emissions scenario. These increases are contingent on fisheries reforms, continued advances in feed technology and the establishment of effective mariculture governance and best practices. Furthermore, dramatically curbing emissions is essential for reducing inequities, increasing reform efficacy and mitigating risks unaccounted for in our analysis. Although climate change will challenge the ocean’s ability to meet growing food demands, the ocean could produce more food than it does currently through swift and ambitious action to reduce emissions, reform capture fisheries and expand sustainable mariculture operations.
转自：科学网
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