Nature, 5 May 2022, VOL 605, ISSUE 7908
《自然》2022年5月5日，第605卷，7908期
天文学Astronomy
A 62-minute orbital period black widow binary in a wide hierarchical triple
宽三星系统、轨道周期为62分钟的黑寡妇双星
作者：Kevin B. Burdge, Thomas R. Marsh, Jim Fuller, Eric C. Bellm, Ilaria Caiazzo, Deepto Chakrabarty, et al.
链接：
https://www.nature.com/articles/s41586-022-04551-1
摘要：
近距离双星系统中，超过十几个毫秒的脉冲星正在消融低质量伴星。在最初的“黑寡妇”中，八小时轨道周期使脉冲星PSR J1959+2048（PSR B1957+20）变暗，其高能辐射持续爆发，并可能最终摧毁一个低质量伴星。
黑寡妇双星不仅是一个“物理实验室”，揭示了将近距离伴星暴露在脉冲星相对能量输出下的有趣结果，还被认为包含一些质量最大的中子星，从而可对中子星状态方程进行可靠的测试。
研究组报道了对ZTF J1406+1222的观测，这是一个宽三星系统、轨道周期为62分钟的黑寡妇双星候选者，其光通量变化超过10倍。ZTF J1406+1222突破了进化模型的界限，低于富氢系统80分钟的最小轨道周期。
宽三星系统的伴星是一颗罕见的低金属丰度冷亚矮星，该系统有一个星系晕轨道，与经过银河系中心附近的轨道一致，这使其成为一个关于形成通道、中子星“踢”物理学和双星演化的探测器。
Abstract：
Over a dozen millisecond pulsars are ablating low-mass companions in close binary systems. In the original ‘black widow’, the eight-hour orbital period eclipsing pulsar PSR J1959+2048 (PSR B1957+20), high-energy emission originating from the pulsar is irradiating and may eventually destroy a low-mass companion. These systems are not only physical laboratories that reveal the interesting results of exposing a close companion star to the relativistic energy output of a pulsar, but are also believed to harbour some of the most massive neutron stars, allowing for robust tests of the neutron star equation of state. Here we report observations of ZTF J1406+1222, a wide hierarchical triple hosting a 62-minute orbital period black widow candidate, the optical flux of which varies by a factor of more than ten. ZTF J1406+1222 pushes the boundaries of evolutionary models, falling below the 80-minute minimum orbital period of hydrogen-rich systems. The wide tertiary companion is a rare low-metallicity cool subdwarf star, and the system has a Galactic halo orbit consistent with passing near the Galactic Centre, making it a probe of formation channels, neutron star kick physics and binary evolution.
物理学Physics
Single electrons on solid neon as a solid-state qubit platform
氖冰上单电子构建固态量子比特平台
作者：Xianjing Zhou, Gerwin Koolstra, Xufeng Zhang, Ge Yang, Xu Han, Brennan Dizdar, et al.
链接：
https://www.nature.com/articles/s41586-022-04539-x
摘要：
量子计算机的实现需要其组成构建块（量子比特）的持续进步。同时体现长相干、快速运算和较大可扩展性的新型量子比特平台在量子计算机和许多其他量子信息系统的构建中具有引人注目的优势。
电子是普遍存在的具有非零电荷、自旋和质量的基本粒子，通常被认为是典型的局域量子信息载体。尽管具有优越的可控性和可配置性，但它们作为量子比特在运动或自旋状态下的实际性能关键取决于它们的物质环境。
研究组报道他们通过实验实现了一个量子比特平台，基于真空中孤立单电子被捕获在超洁净氖冰表面。通过在电路量子电动力学结构中集成电子阱，研究组在芯片上的超导谐振器中实现了单个电子和单个微波光子运动态之间的强耦合。
通过量子比特门运算和色散读出，研究组测出能量弛豫时间T1为15 μs，相位相干时间T2超过200 ns。这些结果表明，电子-氖冰量子比特的性能已接近电荷量子比特的最新水平。
Abstract：
Progress towards the realization of quantum computers requires persistent advances in their constituent building blocks—qubits. Novel qubit platforms that simultaneously embody long coherence, fast operation and large scalability offer compelling advantages in the construction of quantum computers and many other quantum information systems. Electrons, ubiquitous elementary particles of non-zero charge, spin and mass, have commonly been perceived as paradigmatic local quantum information carriers. Despite superior controllability and configurability, their practical performance as qubits through either motional or spin states depends critically on their material environment. Here we report our experimental realization of a qubit platform based on isolated single electrons trapped on an ultraclean solid neon surface in vacuum. By integrating an electron trap in a circuit quantum electrodynamics architecture, we achieve strong coupling between the motional states of a single electron and a single microwave photon in an on-chip superconducting resonator. Qubit gate operations and dispersive readout are implemented to measure the energy relaxation time T1 of 15 μs and phase coherence time T2 over 200 ns. These results indicate that the electron-on-solid-neon qubit already performs near the state of the art for a charge qubit.
Uniform nucleation and epitaxy of bilayer molybdenum disulfide on sapphire
蓝宝石上双层二硫化钼的均匀形核和外延
作者：Lei Liu, Taotao Li, Liang Ma, Weisheng Li, Si Gao, Wenjie Sun, et al.
链接：
https://www.nature.com/articles/s41586-022-04523-5
摘要：
二维过渡金属二卤化物（TMD）是超硅电子领域的研究热点。有研究认为，与单层TMD相比，双层TMD具有更好的静电控制、更小的带隙和更高的迁移率，有望改善晶体管的能量延迟产物。虽然单层TMD的生长取得了进展，但多层TMD的可控外延生长仍是一个挑战。
研究组报道了双层二硫化钼（MoS2）在c-面蓝宝石上的均匀形核（>99%）。他们设计了c-面蓝宝石上的原子平台高度，以实现边缘形核机制，并将MoS2畴合并成连续的厘米级薄膜。
基于双层MoS2通道制造的场效应晶体管（FET）器件在迁移率（高达122.6 cm2 V−1 s−1）和变异性方面，与基于单层膜的FET器件相比有显著改善。此外，短通道FET的通态电流为1.27 mA μm−1，超越了高性能FET的2028路线图目标。
Abstract：
Two-dimensional transition-metal dichalcogenides (TMDs) are of interest for beyond-silicon electronics. It has been suggested that bilayer TMDs, which combine good electrostatic control, smaller bandgap and higher mobility than monolayers, could potentially provide improvements in the energy-delay product of transistors. However, despite advances in the growth of monolayer TMDs, the controlled epitaxial growth of multilayers remains a challenge. Here we report the uniform nucleation (>99%) of bilayer molybdenum disulfide (MoS2) on c-plane sapphire. In particular, we engineer the atomic terrace height on c-plane sapphire to enable an edge-nucleation mechanism and the coalescence of MoS2domains into continuous, centimetre-scale films. Fabricated field-effect transistor (FET) devices based on bilayer MoS2 channels show substantial improvements in mobility (up to 122.6 cm2 V−1 s−1) and variation compared with FETs based on monolayer films. Furthermore, short-channel FETs exhibit an on-state current of 1.27mA μm−1, which exceeds the 2028 roadmap target for high-performance FETs.
材料科学Materials Science
Observation of chiral and slow plasmons in twisted bilayer graphene
扭曲双层石墨烯中手性和慢等离子体的观测
作者：Tianye Huang, Xuecou Tu, Changqing Shen, Binjie Zheng, Junzhuan Wang, Hao Wang, et al.
链接：
https://www.nature.com/articles/s41586-022-04520-8
摘要：
莫尔超晶格已引发对奇异涌现电子特性的观测，例如小旋转角扭曲双层石墨烯（tBLG）中的超导性和强关联态。最近，这些发现激发了人们对莫尔等离子体新特性的探索。虽然近场纳米成像技术已经研究了等离子体在tBLG基面中的传播，但这些等离子体的一般电磁特性和性质仍不清楚。
研究组报道了在一个高度有序莫尔超晶格的宏观tBLG中直接观测到两种新的等离子体模式。利用tBLG的螺旋结构纳米带，研究组确定了因光泵浦下电子气未补偿Berry通量而产生的手性等离子体特征。这些手性等离子体的显著特征表现在它们对光泵浦强度和电子填充的依赖，以及与最大Berry通量光谱窗口相一致的明显共振分裂和法拉第旋转。
此外，研究组还发现了0.4电子伏特左右的慢等离子体模式，这源于晶格-弛豫AB-堆叠畴中嵌套子带之间的带间跃迁。这种模式有望在常用的中波红外光谱窗口内为强光-物质相互作用提供机会。
该研究结果揭示了小角度tBLG的新电磁动力学特性，证明其可作为一个独特的量子光学平台。
Abstract：
Moiré superlattices have led to observations of exotic emergent electronic properties such as superconductivity and strong correlated states in small-rotation-angle twisted bilayer graphene (tBLG). Recently, these findings have inspired the search for new properties in moiré plasmons. Although plasmon propagation in the tBLG basal plane has been studied by near-field nano-imaging techniques, the general electromagnetic character and properties of these plasmons remain elusive. Here we report the direct observation of two new plasmon modes in macroscopic tBLG with a highly ordered moiré superlattice. Using spiral structured nanoribbons of tBLG, we identify signatures of chiral plasmons that arise owing to the uncompensated Berry flux of the electron gas under optical pumping. The salient features of these chiral plasmons are shown through their dependence on optical pumping intensity and electron fillings, in conjunction with distinct resonance splitting and Faraday rotation coinciding with the spectral window of maximal Berry flux. Moreover, we also identify a slow plasmonic mode around 0.4 electronvolts, which stems from the interband transitions between the nested subbands in lattice-relaxed AB-stacked domains. This mode may open up opportunities for strong light–matter interactions within the highly sought after mid-wave infrared spectral window. Our results unveil the new electromagnetic dynamics of small-angle tBLG and exemplify it as a unique quantum optical platform.
Self-regulated non-reciprocal motions in single-material microstructures
单一材料微结构中的自调节非互易运动
作者：Shucong Li, Michael M. Lerch, James T. Waters, Bolei Deng, Reese S. Martens, Yuxing Yao, et al.
链接：
https://www.nature.com/articles/s41586-022-04561-z
摘要：
活纤毛通过复杂弯曲和扭曲的旋转冲程进行搅动、扫掠和转向，并伴有明显的反向弧线。综合模拟此类动力学常依赖于多材料设计，但在规划任意运动或同一结构的不同行为时面临限制。
研究组展示了如何通过自我调节，在单一材料系统中出现多样、复杂、非互易、类似冲程的轨迹。当一个由基元-结构轴倾斜排列的光响应液晶弹性体组成的微柱暴露在静态光源下时，动态舞蹈随着光启动一个有序到无序的运动过渡前沿而演变，通过多级光-化学-机械反馈，瞬间将结构转变为复杂的、不断演变的、扭转和弯曲的双晶片。
正如该理论模型所捕捉到的，运动前沿不断地改变分子轴、几何轴和照明轴的方向，从而产生由一系列扭转、弯曲、避光和向光运动组成的路径。在该模型的指导下，研究组通过调整参数，包括照明角度、光强、分子各向异性、微结构几何形状、温度和辐照间隔以及持续时间，设计了一系列的广泛轨迹。
研究组进一步展示了这种光-化学-机械自我调节如何通过光介导的干预通信，以及连接微结构的复杂运动，在紧密间隔的微结构阵列中创建自组织变形模式。这对软体机器人、生物医学设备和能量转换材料等领域的自主多模态致动器，以及对自我调节系统的基本认知具有广泛意义。
Abstract：
Living cilia stir, sweep and steer via swirling strokes of complex bending and twisting, paired with distinct reverse arcs. Efforts to mimic such dynamics synthetically rely on multimaterial designs but face limits to programming arbitrary motions or diverse behaviours in one structure. Here we show how diverse, complex, non-reciprocal, stroke-like trajectories emerge in a single-material system through self-regulation. When a micropost composed of photoresponsive liquid crystal elastomer with mesogens aligned oblique to the structure axis is exposed to a static light source, dynamic dances evolve as light initiates a travelling order-to-disorder transition front, transiently turning the structure into a complex evolving bimorph that twists and bends via multilevel opto-chemo-mechanical feedback. As captured by our theoretical model, the travelling front continuously reorients the molecular, geometric and illumination axes relative to each other, yielding pathways composed from series of twisting, bending, photophobic and phototropic motions. Guided by the model, here we choreograph a wide range of trajectories by tailoring parameters, including illumination angle, light intensity, molecular anisotropy, microstructure geometry, temperature and irradiation intervals and duration. We further show how this opto-chemo-mechanical self-regulation serves as a foundation for creating self-organizing deformation patterns in closely spaced microstructure arrays via light-mediated interpost communication, as well as complex motions of jointed microstructures, with broad implications for autonomous multimodal actuators in areas such as soft robotics, biomedical devices and energy transduction materials, and for fundamental understanding of self-regulated systems.
社会学Sociology
Virtual communication curbs creative idea generation
虚拟交流限制创意产生
作者：Melanie S. Brucks & Jonathan Levav
链接：
https://www.nature.com/articles/s41586-022-04643-y
摘要：
新冠疫情加速了长达十年的远程工作转变，使居家工作大规模正常化。事实上，在2021年的一项调查中，75%的美国员工表示他们个人倾向于每周至少远程工作一天，研究估计，疫情结束后，美国20%的工作日将在家进行。
研究组考察了这种远离面对面互动的转变如何影响创新，创新依赖于协作生成创意，这是商业和科学进步的基础。在一项横跨五个国家（欧洲、中东和南亚）的实验室研究和现场实验中，研究组发现视频会议抑制了创意的产生。
相比之下，当选择跟进哪个创意时，研究组未发现任何证据表明视频会议小组的效果不如面对面小组（初步证据表明他们可能更有效）。此前理论侧重于口头和书面技术如何限制信息交流的同步性和范围，研究组发现，该影响由视频会议和面对面互动的物理性质差异所驱动。
具体来说，通过眼睛注视和回忆评估，以及潜在语义分析，研究组证明视频会议阻碍了创意的产生，因为它将交流者的注意力集中在屏幕上，这会导致认知焦点的缩小。研究结果表明，虚拟互动会给创意产生带来认知成本。
Abstract：
COVID-19 accelerated a decade-long shift to remote work by normalizing working from home on a large scale. Indeed, 75% of US employees in a 2021 survey reported a personal preference for working remotely at least one day per week, and studies estimate that 20% of US workdays will take place at home after the pandemic ends. Here we examine how this shift away from in-person interaction affects innovation, which relies on collaborative idea generation as the foundation of commercial and scientific progress. In a laboratory study and a field experiment across five countries (in Europe, the Middle East and South Asia), we show that videoconferencing inhibits the production of creative ideas. By contrast, when it comes to selecting which idea to pursue, we find no evidence that videoconferencing groups are less effective (and preliminary evidence that they may be more effective) than in-person groups. Departing from previous theories that focus on how oral and written technologies limit the synchronicity and extent of information exchanged, we find that our effects are driven by differences in the physical nature of videoconferencing and in-person interactions. Specifically, using eye-gaze and recall measures, as well as latent semantic analysis, we demonstrate that videoconferencing hampers idea generation because it focuses communicators on a screen, which prompts a narrower cognitive focus. Our results suggest that virtual interaction comes with a cognitive cost for creative idea generation.
转自：学术猫
如有侵权，请联系本站删除！
