Science, 23 JUN 2023, VOL 380, ISSUE 6651

《科学》2023年6月23日，第380卷，6651期

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物理学Physics

Hunting for Majoranas

寻觅马约拉纳准粒子

▲ 作者：Ali Yazdani, Felix von Oppen, Bertrand I. Halperin Amir Yacoby

▲ 链接：https://www.science.org/doi/10.1126/science.ade0850

▲ 择要：

于已往十年里，人们支付了相称年夜的起劲，以于新型量子质料以及器件中不雅测非阿贝尔准粒子。这些起劲的念头是为了证实逾越费米子以及博色子的准粒子的量子统计，并为创立拓扑掩护量子比特成立根蒂根基科学。

于这篇综述中，研究组聚焦在起劲创立具备马约拉纳零模的拓扑超导相。他们思量了从现有试验事情中吸取的经验教训，这些经验教训鞭策着对于现有平台的革新以及新要领的摸索。

只管非阿贝尔准粒子的试验探测仍颇具应战性，但迄今为止人们所得到的常识以及将来机缘，将为量子物理学这一使人高兴范畴的发明以及前进提供伟大潜力。

▲ Abstract：

Over the past decade, there have been considerable efforts to observe non-abelian quasiparticles in novel quantum materials and devices. These efforts are motivated by the goals of demonstrating quantum statistics of quasiparticles beyond those of fermions and bosons and of establishing the underlying science for the creation of topologically protected quantum bits. In this Review, we focus on efforts to create topological superconducting phases that host Majorana zero modes. We consider the lessons learned from existing experimental efforts, which are motivating both improvements to present platforms and the exploration of new approaches. Although the experimental detection of non-abelian quasiparticles remains challenging, the knowledge gained thus far and the opportunities ahead offer high potential for discovery and advances in this exciting area of quantum physics.

Mid-circuit correction of correlated phase errors using an array of spectator qubits

哄骗傍观者量子位阵列对于相干相位偏差举行中路校订

▲ 作者：K. Singh, C. E. Bradley, S. Anand, V. Ramesh, R. White H. Bernien.

▲ 链接：https://www.science.org/doi/10.1126/science.ade5337

▲ 择要：

扩大老是轻易堕落的量子处置惩罚器是一项艰难应战。虽然量子纠错终极包管了容错操作，但所需的重大量子位数以及过错阈值使人望而却步。于一项增补和谈中，共置辅助“傍观者”量子位充任噪声的原位探针，并实现对于数据量子位过错的及时、相关改正。

研究组使用铯傍观者量子位阵列来校订铷数据量子位阵列上的相干相位偏差。经由过程联合挨次读出、数据处置惩罚以及前馈操作，这些相干偏差于量子电路的履行中有所降低。

该和谈广泛合用在量子信息平台，成立了扩大中性原子量子处置惩罚器的要害东西：原子阵列的中路读出、及时处置惩罚以及前馈，和原子量子位的相关中路重装。

▲ Abstract：

Scaling up invariably error-prone quantum processors is a formidable challenge. Although quantum error correction ultimately promises fault-tolerant operation, the required qubit overhead and error thresholds are daunting. In a complementary proposal, colocated, auxiliary “spectator” qubits act as in situ probes of noise and enable real-time, coherent corrections of data qubit errors. We used an array of cesium spectator qubits to correct correlated phase errors on an array of rubidium data qubits. By combining in-sequence readout, data processing, and feedforward operations, these correlated errors were suppressed within the execution of the quantum circuit. The protocol is broadly applicable to quantum information platforms and establishes key tools for scaling neutral-atom quantum processors: mid-circuit readout of atom arrays, real-time processing and feedforward, and coherent mid-circuit reloading of atomic qubits.

质料科学Materials Science

Superconducting vortices carrying a temperature-dependent fraction of the flux quantum

携带通量量子温度相干分数的超导涡旋

▲ 作者：Yusuke Iguchi, Kunihiro Kihou, Chul-Ho Lee, Mats Barkman, Andrea L. Benfenati, Vadim Grinenko, et al.

▲ 链接：https://www.science.org/doi/10.1126/science.abp9979

▲ 择要：

磁场经由过程造成量子涡旋（包抄的磁通量等在磁通量量子）穿透II型体超导体。磁通量量子是一个只依靠在基本常数的普适当。

研究组使用扫描超导量子干预干与装配（SQUID）磁强计研究了空穴过掺杂Ba1?xKxFe2As2 （x = 0.77）中的伶仃涡旋。于很多处所，研究组不雅察到的涡旋只携带部门磁通量量子，其巨细随温度持续变迁。

研究组展示了这些涡旋的可挪动性以及可把持性，并将其注释为具备非普适当子化（分数）磁通量的量子涡旋，其巨细由多组分超导体的温度相干参数决议。

▲ Abstract：

Magnetic field penetrates type-II bulk superconductors by forming quantum vortices that enclose a magnetic flux equal to the magnetic flux quantum. The flux quantum is a universal quantity that depends only on fundamental constants. In this study, we investigated isolated vortices in the hole-overdoped Ba1?xKxFe2As2 (x = 0.77) by using scanning superconducting quantum interference device (SQUID) magnetometry. In many locations, we observed objects that carried only part of a flux quantum, with a magnitude that varied continuously with temperature. We demonstrated mobility and manipulability of these objects and interpreted them as quantum vortices with nonuniversally quantized (fractional) magnetic flux whose magnitude is determined by the temperature-dependent parameters of a multicomponent superconductor.

Deformable hard tissue with high fatigue resistance in the hinge of bivalve Cristaria plicata

双壳纲褶纹冠蚌搭钮中具备高抗疲惫性的可变形硬构造

▲ 作者：Xiang-Sen Meng, Li-Chuan Zhou, Lei Liu, Yin-Bo Zhu, Yu-Feng Meng, Dong-Chang Zheng, et al.

▲ 链接：https://www.science.org/doi/10.1126/science.ade2038

▲ 择要：

双壳纲植物的外壳搭钮于其平生中可蒙受数十万次反复的双壳开合运动。

研究组切磋了双壳纲褶纹冠蚌搭钮中矿化构造的分层设计，这使患上构造具备可变形性以及抗疲惫性，从而奠基了反复运动威力的根蒂根基。这类折叠的扇形构造由嵌入弹性基质中的径向摆列的脆性文石纳米线构成，可将外部径向载荷转化为周向变形。

软硬复合微不雅布局可按捺构造内的应力集中。沿纳米线纵向标的目的的相关纳米孪晶界增长了其抗弯曲断裂的威力。这类不平常的生物矿物经由过程多标准布局设计哄骗了每一种身分的固有特征，为抗疲惫布局质料的蜕变提供了新见解。

▲ Abstract：

The hinge of bivalve shells can sustain hundreds of thousands of repeating opening-and-closing valve motions throughout their lifetime. We studied the hierarchical design of the mineralized tissue in the hinge of the bivalve Cristaria plicata, which endows the tissue with deformability and fatigue resistance and consequently underlies the repeating motion capability. This folding fan–shaped tissue consists of radially aligned, brittle aragonite nanowires embedded in a resilient matrix and can translate external radial loads to circumferential deformation. The hard-soft complex microstructure can suppress stress concentration within the tissue. Coherent nanotwin boundaries along the longitudinal direction of the nanowires increase their resistance to bending fracture. The unusual biomineral, which exploits the inherent properties of each component through multiscale structural design, provides insights into the evolution of antifatigue structural materials.

化学Chemistry

Facile mechanochemical cycloreversion of polymer cross-linkers enhances tear resistance

聚合物交联剂的简略单纯机械化学裂环加强了抗扯破性

▲ 作者：Shu Wang, Yixin Hu, Tatiana B. Kouznetsova, Liel Sapir, Danyang Chen, Abraham Herzog-Arbeitman, et al.

▲ 链接：https://www.science.org/doi/10.1126/science.adg3229

▲ 择要：

共价聚合物收集的机械机能凡是源在聚合物链的永世结尾毗连或者交联，更易断裂的份子毗连物可能会孕育发生扯破所需能量更少的质料。

研究组报导称，基在环丁烷的力敏基团交联剂冲破了力触发的裂环作用，孕育发生的聚合物收集韧性是传统近似物的九倍。这类反映归因在长而强的主聚合物链以及交联剂剪切力的联合，于不异时间标准下，这些力比比照交联剂小约五倍。

加强的韧性没有与非共价交联相干的滞后征象，且于两种差别的丙烯酸酯弹性体中，于疲惫以及恒定位移速度张力下，和于凝胶以及弹性体中均不雅察到该韧性。

▲ Abstract：

The mechanical properties of covalent polymer networks often arise from the permanent end-linking or cross-linking of polymer strands, and molecular linkers that break more easily would likely produce materials that require less energy to tear. We report that cyclobutane-based mechanophore cross-linkers that break through force-triggered cycloreversion lead to networks that are up to nine times as tough as conventional analogs. The response is attributed to a combination of long, strong primary polymer strands and cross-linker scission forces that are approximately fivefold smaller than control cross-linkers at the same timescales. The enhanced toughness comes without the hysteresis associated with noncovalent cross-linking, and it is observed in two different acrylate elastomers, in fatigue as well as constant displacement rate tension, and in a gel as well as elastomers.

地球科学Earth Science

Large herbivore diversity slows sea ice–associated decline in arctic tundra diversity

年夜型食草植物的多样性缓解了北极苔原海冰相干的多样性降落

▲ 作者：Eric Post, Elina Kaarlej?rvi, Marc Macias-Fauria, David A. Watts, Pernille Sporon B?ving, Sean M. P. Cahoon, et al.

▲ 链接：https://www.science.org/doi/10.1126/science.add2679

▲ 择要：

因为包孕天气强制于内的多种人类压力要素，全世界生物多样性正鄙人降。然而，局部多样性趋向于某些分类群中其实不一致，恍惚下场部历程对于全世界模式的孝敬。

于一项为期15年的试验中，跟着天气变暖，包孕动物、真菌以及地衣的北极苔原多样性有所降落，已经知会影响苔原植被构成的年夜型食草植物被解除于外。因为生长季的配景温度跟着海冰的削减而上升，不管试验处置惩罚怎样，苔原多样性都鄙人降。

然而，有年夜型食草植物时，多样性降落的速率比没有年夜型食草植物时慢。这类差异与年夜型食草植物有用多样性的增长有关，由于此前数目富厚的北美驯鹿削减了，麝牛数目增长。促成食草植物多样性的起劲，如从头造林，或者有助在减轻天气变暖对于苔原多样性的影响。

▲ Abstract：

Biodiversity is declining globally in response to multiple human stressors, including climate forcing. Nonetheless, local diversity trends are inconsistent in some taxa, obscuring contributions of local processes to global patterns. Arctic tundra diversity, including plants, fungi, and lichens, declined during a 15-year experiment that combined warming with exclusion of large herbivores known to influence tundra vegetation composition. Tundra diversity declined regardless of experimental treatment, as background growing season temperatures rose with sea ice loss. However, diversity declined slower with large herbivores than without them. This difference was associated with an increase in effective diversity of large herbivores as formerly abundant caribou declined and muskoxen increased. Efforts that promote herbivore diversity, such as rewilding, may help mitigate impacts of warming����APP on tundra diversity.

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