Detecting individual light quanta is essential for quantum information, space exploration, advanced machine vision, and fundamental science. In this work, we introduce a single-photon detection mechanism using highly photosensitive nonequilibrium electron phases in moiré materials. Using tunable bands in bilayer graphene/hexagonal boron nitride superlattices, we engineer negative differential conductance and a sensitive bistable state capable of detecting single photons. Operating in this regime, we demonstrate single-photon counting at mid-infrared (11.3 micrometers) and visible wavelengths (675 nanometers) and temperatures up to 25 kelvin. This detector offers prospects for broadband, high-temperature quantum technologies with complementary metal-oxide semiconductor compatibility and seamless integration into photonic-integrated circuits. Our analysis suggests that the underlying mechanism originates from superlattice-induced negative differential velocity.
Imaging collective quantum fluctuations of the structure of a complex molecule
复杂分子结构的集体量子涨落成像
▲ 作者：BENO?T RICHARD, REBECCA BOLL, SOURAV BANERJEE, JULIA M. SCH?FER, ZOLTAN JUREK, GREGOR KASTIRKE, ET AL.
Because of the Heisenberg uncertainty principle, the structure of a molecule fluctuates about its mean geometry, even in the ground state. Observing this fundamental quantum effect experimentally—particularly, revealing the collective nature of the structural quantum fluctuations—remains an unmet challenge for complex molecules. In this work, we achieved this for an 11-atom molecule by inducing its Coulomb explosion with an x-ray free-electron laser. We show that the structural fluctuations manifest themselves in correlated variations of ion momenta obtained through coincident detection of the atomic fragments from individual molecules. Our analysis scheme allows extracting these variations, despite our measurements covering only a fraction of the full 33-dimensional momentum space, thereby establishing a general approach for extracting information on high-dimensional structural dynamics using Coulomb explosion.
材料科学Materials Science
Strain-coupled, crystalline polymer-inorganic interfaces for efficient magnetoelectric sensing
应变耦合结晶聚合物-无机界面助力高效磁电传感
▲ 作者：BINBIN HE, YUANYUAN HE, WENHUI WANG, YINGZHI SUN, SHENGWEN KONG, JIN HUANG, ET AL.
Magnetoelectric sensing holds promise for flexible sensors, offering precise detection of both electric and magnetic fields with minimal power consumption. However, its practical use has been constrained by weak magnetoelectric effects and limited overall performance, particularly under mechanical strain. Herein, we fabricated robust magnetoelectric polymer-inorganic nanocomposites through an interfacial cocrystallization strategy. By leveraging diazonium chemistry on vanadium diselenide (VSe2) monolayers, we created a submolecular-flat interface between ferromagnetic VSe2 and ferroelectric poly(vinylidene fluoride) (PVDF) nanocrystals. This highly crystalline interface has few mobile polymer chains and thus limits energy dissipation and enhances interfacial energy transfer. The scalable composite films show exceptional magnetoelectric performance, with a magnetocapacitive coefficient of 23.6%. These films enable ultrafast magnetoelectric detection, approaching a 10-fold increase in speed compared with conventional sensors, and offer opportunities for integrating multifunctional materials such as thermoelectric coolers into wearable devices.
Three-dimensional nucleation and growth of deformation twins in magnesium
镁中变形孪晶的三维形核与长大
▲ 作者：SANGWON LEE, MICHAEL PILIPCHUK, CAN YILDIRIM, DUNCAN GREELEY, QIANYING SHI, TRACY D. BERMAN, ET AL.
At two-thirds the weight of aluminum, magnesium alloys have the potential to reduce the fuel consumption of transportation vehicles. These advancements depend on our ability to optimize the desirable versus undesirable effects of deformation twins, which are three-dimensional (3D) microstructural domains that form under mechanical stresses. Previously only characterized through surface or thin-film measurements, we present 3D in situ characterization of deformation twinning inside an embedded grain over mesoscopic fields of view using dark-field x-ray microscopy supported by crystal plasticity finite element analysis. The results revealed the role of triple junctions on twin nucleation and the sequence and irregularity of twin growth and showed that twin-grain junctions, twin-twin junctions, and twin boundaries were the sites of localized dislocation accumulation.
生命科学Life Science
The membrane skeleton is constitutively remodeled in neurons by calcium signaling
膜骨架通过钙信号传导在神经元中组成型重塑
▲ 作者：EVAN HELLER HTTPS://ORCID.ORG/0009-0005-4405-7089, NAINA KURUP HTTPS://ORCID.ORG/0000-0003-2160-0622, AND XIAOWEI ZHUANG
The membrane skeleton in neurons adopts a periodic lattice structure in which actin filaments, capped by adducin and tropomodulin, form ring-shaped structures connected by spectrin tetramers along neurites. This membrane-associated periodic skeleton (MPS) is important for many neuronal functions. Using live-cell super-resolution imaging, we found that the MPS is surprisingly dynamic, undergoing local disassembly and reformation constitutively in axons. MPS remodeling is driven by calcium signaling, leading to actin-ring destabilization through protein kinase C–mediated adducin phosphorylation and to spectrin degradation by calpain. Formin, an actin-nucleating and -polymerizing enzyme, plays a dual role in MPS remodeling and maintenance. MPS remodeling is enhanced by neuronal activity and functionally facilitates endocytosis. Our results highlight the importance of a dynamic membrane skeletal structure in neuronal function.
Immune system influence on physiology
免疫系统对生理的影响
▲ 作者：MATTHIAS NAHRENDORF, FLORENT GINHOUX AND FILIP K. SWIRSKI
The immune system’s central function is to maintain homeostasis by guarding the organism against dangerous external and internal stressors. Immunity’s operational toolbox contains diverse processes, such as phagocytosis, antigen recognition, cell killing, and secretion of cytokines and antibodies. Although immune cells interact with each other, they also communicate with cells typically associated with other organ systems, including the nervous, circulatory, metabolic, musculoskeletal, endocrine, and hematopoietic. This abundant cross-talk shows that immunity transcends defense and homeostasis: It is a network that participates in many physiological processes necessary for life. By accessing the circulation and inhabiting every tissue, leukocytes sense, interpret, and regulate biological processes. In this Review, we highlight recent studies that illustrate the often bidirectional and symbiotic relationships through which the immune system regulates physiology.
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