分类： 统计学 >> 社会统计学 提交时间： 2024-06-28 合作期刊: 《中国科学院院刊》
摘要： 随着现代科技的发展，重力学与地震学、地质学、基础物理学、地球动力学、水文学、海洋学和天文 学等众多学科交叉融合并蓬勃发展，是服务国家测绘基准、资源勘探、军事安全及灾害监测等战略需求和基 础地球科学问题研究的关键学科，因此掌握重力学的核心技术是国家核心竞争力的重要体现。文章在分析我 国重力学学科发展的历史、现状、机遇与挑战的基础上，提出了重力学学科未来发展方向与重点思考内容， 涉及海陆天空一体化的立体重力观测技术，海陆天空统一的大地测量重力基准网，地球系统质量迁移与青藏 高原动力学问题研究，面向国防安全与太空的重力学，以及发展人工智能等新技术在重力学研究中的应 用等。
分类： 统计学 >> 社会统计学 提交时间： 2024-06-28 合作期刊: 《中国科学院院刊》
摘要： 生命科学发展日新月异，伴随着大量实验技术的更新，生物大数据逐渐产生并在生命科学研究中扮演 着日益重要的角色。首先，生物大数据具有多样性和复杂性，包括基因组数据、表观基因组数据、蛋白质组 数据等多种类型。这些数据为研究人员提供了更全面的信息，有助于揭示生命现象背后的规律。其次，数据 驱动的生命科学新发展和应用涵盖了基因编辑、精准医疗、药物研发等诸多领域，为人类健康和生命质量提 供了前所未有的可能性。然而，生命科学研究大数据时代也面临着包括数据存储、数据共享、隐私保护等多 方面的问题，以及如何将海量数据转化为可靠的科学发现等挑战。文章简要概括了生物数据推动生命科学的 发展规律，梳理了生物大数据组成、特点及来源，阐述并讨论了数据驱动的生命科学研究新范式下的共性问 题和我国面临的挑战。
分类： 统计学 >> 社会统计学 提交时间： 2024-06-28 合作期刊: 《中国科学院院刊》
摘要： 以智能科技为核心技术、智能算力为生产力的智能时代再次把脑科学推向世界科学与技术前沿。脑科 学是研究人、动物和机器的认知与智能的本质和规律的科学。对神经系统结构和功能联结规律进行全面解析 将最终绘制成脑功能联结图谱，近10 多年来神经科学研究致力于系统性地解析神经系统的神经元类型和神经 结构连接，在单细胞转录组分析、神经网络结构示踪等技术推动下取得了阶段性进展。解析人类大脑这一最 为复杂的信息和智能系统，会启迪类脑智能理论和类脑智能技术，即脑科学/神经科学启发的智能理论和技 术。在智能时代，脑科学研究的多学科交叉研究范式促使脑机接口、类脑智能计算等类脑智能研究领域加入 脑科学。脑机接口的神经解码和编码技术为绘制人脑功能神经网络图谱提供了重要的功能研究技术和方法， 并且可探索在脑疾病临床诊治上的应用。类脑计算正成为脑科学研究的一种新范式，借鉴脑处理信息和学习 的基本原理发展高能效、高速和智能的新型类脑计算系统，利用发展的类脑计算系统可以加速发展脑模拟和 数字大脑，促进理解大脑运行机制和治疗脑疾病，发展数字脑科学和脑医学。新近出现的脉冲神经网络智能 处理器为构建大规模类脑智能计算系统奠定了基础，未来类脑超级算力极可能超过人类大脑算力，影响智能 科技变革和人类社会发展。
分类： 统计学 >> 社会统计学 提交时间： 2024-06-28 合作期刊: 《中国科学院院刊》
摘要： 纳米酶代表了一类新型人工酶和生物催化剂，打破了无机与有机生命的界限。它既有纳米材料的理化 特性，也有独特的类酶催化活性。同时，这些理化特性有可能会调控催化活性，使得纳米酶跟天然酶、传统 的模拟酶和化学催化剂区别开来。纳米酶有比较好的稳定性、耐高温、低温、耐酸碱、活性可调且多功能， 目前受到了广泛关注，在生物医药、环境治理、绿色农业、新能源等领域展现出巨大的应用前景，并初步形 成了相应的学科框架。为了更好地推动纳米酶的发展，拓展对纳米酶的认识，文章回顾了纳米酶发现，分析 凝练了纳米酶的学科特点及其结构，综述了纳米酶的应用，并展望了未来的发展趋势。
分类： 统计学 >> 社会统计学 提交时间： 2024-06-28 合作期刊: 《中国科学院院刊》
摘要： 新药研发是医药创新发展的关键环节，是新一轮生命科技革命和生物经济变革的核心领域，对引领科 技创新、带动经济发展、提升人民健康福祉具有战略意义。当前，前沿技术不断革新、学科跨域融合、数字 深度赋能驱动新药研发领域创新日趋活跃，国内外创新性小分子药物、抗体药物、免疫细胞治疗、基因治疗 与核酸药物等密集获批上市，为未满足的临床需求提供更多选择。文章深入分析新药研发领域发展趋势、全 球新药批准情况，以及我国新药研发发展现状与态势，提出发展启示与建议，以期为新药研发领域发展提供 参考。
分类： 统计学 >> 社会统计学 提交时间： 2024-06-28 合作期刊: 《中国科学院院刊》
摘要： 基于生态系统的海洋管理是海洋生态文明建设的重要手段。我国当前的海洋生态分类分区工作通过全 面梳理海洋生态系统类型和自然地理特征，将我国近海按照不同尺度划分为若干等级的生态空间单元，有效 刻画了海洋生物群落及其栖息地的地理分布特征，对于支撑基于生态系统的海洋管理具有重要作用。文章分 析了海洋生态分类分区的现实意义，回顾了国内外海洋生态分类分区研究和发展历程，介绍了我国海洋生态 分类分区的实践经验和应用前景，并对基于生态系统的海洋管理实现路径提出建议。
分类： 统计学 >> 社会统计学 提交时间： 2024-06-28 合作期刊: 《中国科学院院刊》
摘要： 新质生产力是一个战略性的概念，可以将其定义为所有能够促进基于技术进步之上提高单位产品科技 含量和附加值的经济活动。讨论新质生产力必须要正确理解基于技术进步之上的产业升级，避免“一刀切”， 将新质生产力限制在特定发展领域，认为新质生产力是技术决定论。发展新质生产力要关注基础研究、应用 技术、金融系统3 个核心生产要素，同时通过推动制度型高水平开放、营造良好的营商环境、打造开放的国 际化人才体系，提供一个有效的发展新质生产力的支持环境。
分类： 统计学 >> 社会统计学 提交时间： 2024-06-28 合作期刊: 《中国科学院院刊》
摘要： 实现17 项联合国可持续发展目标（SDGs） 是世界各国在2016—2030 年的重要任务，但近期评估显示 有半数目标进展停滞甚至倒退，并且到2030 年世界各国可能无法实现大多数目标。文章在回顾全球及中国实 现17 项SDGs进展的基础上，总结了影响SDGs实现的5 项主要挑战，包括：数据缺失和监测能力不足，不同 SDGs间相互联系的高度复杂性，区域差异和负外部性影响，科学、政策和社会联系不足，以及全球变化对 SDGs实现的不确定性影响。同时，文章从加强政策一致性、聚焦优先目标、强化基础理论研究、提升数据 获取能力4个方面提出了加快中国实现SDGs的对策建议。
分类： 统计学 >> 社会统计学 提交时间： 2024-06-28 合作期刊: 《中国科学院院刊》
摘要： 世纪之交的“人类基因组计划”开启了生命大科学的研究新时代，形成了以整体性高通量研究为特征 的各种生命组学。最初的组学研究主要在分子层次上展开，如基因组学、转录组学、蛋白质组学等，表现出 数据驱动的研究新范式。随着研究技术的发展，组学研究上升到介观层次，其核心是2017 年启动的“人类细 胞图谱”计划。目前，研究者已经能够在组织器官乃至个体水平开展组学研究，通过整合不同层次的组学数 据来认识生命复杂系统。
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Polarization vectors of light traveling in a coiled optical fiber rotate around its propagating axis even in the absence of birefringence. This rotation was usually explained due to the Pancharatnam-Berry phase of spin-1 photons. Here, we use a purely geometric method to understand this rotation. We show that similar geometric rotations also exist for twisted light carrying orbital angular momentum (OAM). The corresponding geometric phase can be applied in photonic OAM-state-based quantum computation and quantum sensing.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： How migratory birds can find the right way in navigating over thousand miles is an intriguing question, which much interested researchers in both fields of biology and physics for centuries. There several putative proposals that sound intuitively plausible all remain contested so far because those hypothesis-models of magnetoreceptor to sense geomagnetic field need either extremely high sensitivity or humankind-like intelligence to guide. Here we explore theoretically that the birds can navigate to their destination through an entirely new scenario to sense the geomagnetic field. Our proposal is based on separate peaks of the resonance-fluorescence spectrum of a four-level system derived from the ferric sulfide cluster which exists in a protein complex (Drosophila CG8198) of migratory birds. As the separation of spectral peaks contains information about geomagnetic field at both current location and birthland, the change of such separation cues the bird to choose a right direction to move and double-resonance emerges once arrived the destination. Our theoretical mechanism can explain previous experiments on the disorientation of migratory birds caused by oscillating magnetic field naturally and more precisely. This work provides insight to explain migratory navigation and motivates possible manmade practical devices.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Conventional coherent absorption occurs only when two incident beams exhibit mirror symmetry with respect to the absorbing surface, i.e., the two beams have the same incident angles, phases, and amplitudes. In this work, we propose a more general metasurface paradigm for coherent perfect absorption, with impinging waves from arbitrary asymmetric directions. By exploiting excitation of unidirectional evanescent waves, the output can be fixed at one reflection direction for any amplitude and phase of the control wave. We show theoretically and confirm experimentally that the relative amplitude of the reflected wave can be tuned continuously from zero to unity by changing the phase difference between the two beams, i.e. switching from coherent perfect absorption to full reflection. We hope that this work will open up promising possibilities for wave manipulation via evanescent waves engineering with applications in optical switches, one-side sensing, and radar cross section control.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： We show that the time-averaged Poynting vector in parity-time (PT ) symmetric coupled waveguides is always positive and cannot explain the stopped light at exceptional points (EPs). In order to solve this paradox, we must accept the fact that the fields E and H and the Poynting vector in non-Hermitian systems are in general complex. Based on the original definition of the instantaneous Poynting vector, a formula on the group velocity is proposed, which agrees perfectly well with that calculated directly from the dispersion curves. It explains not only the stopped light at EPs, but also the fast-light effect near it. This investigation bridges a gap between the classic electrodynamics and the non-Hermitian physics, and highlights the novelty of non-Hermitian optics.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Traditional lasers function using resonant cavities, in which the round-trip optical path is exactly equal to an integer multiple of the intracavity wavelengths to constructively enhance the spontaneous emission rate. By taking advantage of the enhancement from the resonant cavity, the narrowest sub-10-mHz-linewidth laser and a $10^{-16}$-fractional-frequency-stability superradiant active optical clock (AOC) have been achieved. However, a laser with atomic spontaneous radiation being destructively inhibited in an anti-resonant cavity, where the atomic resonance is exactly between two adjacent cavity resonances, has not been reported. Herein, we experimentally demonstrate inhibited stimulated emission and termed it an inhibited laser. Compared with traditional superradiant AOCs, which exhibit superiority in terms of the high suppression of cavity noise, the suppression of the cavity-pulling effect of an inhibited laser can be further improved by a factor of $(2F/pi)^2$, i.e., 2.07 in this work, which was improved from 26 to 53 times. This study will guide further development of AOCs with better stability, and thus, it is significant for quantum metrology and may lead to new research in the laser physics and cavity quantum electrodynamics fields.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Resampling by interpolation is the traditional method to process sample in nonunform sampling Fourier transform spectrometer. Nonuniform discrete Fourier transform is an alternative to interpolation that has not been overlooked before. With the aid of experiment, we systematically compare the NUFFT method with resampling by interpolation FFT method in nonuniform sampling Fourier transform spectrometer. We found that NUFFT is comparable to interpolation in spectral profile and spectral noise levels and is better in spectral amplitudes. We also found that It has significant advantage in under-sampling and anti-aliasing property which is offered by the unique non-periodic nature of nonuniform sampling. It is faster and consumes less computer memory in our python implementation. Overall, we found that NUFFT is superior to traditional interpolation method with mostly better performances as well as additional capabilities.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Xiao Sun
Song Liang
Weiqing Cheng
Shengwei Ye
Yiming Sun
Yongguang Huang
Ruikang Zhang
Jichuan Xiong
Xuefeng Liu
John H. Marsh
Lianping Hou
摘要： We report an AlGaInAs multiple quantum well integrated source of polarization controlled light consisting of a polarization mode converter PMC, differential phase shifter(DPS), and a side wall grating distributed-feedback DFB laser. We demonstrate an asymmetrical stepped-height ridge waveguide PMC to realize TE to TM polarization conversion and a symmetrical straight waveguide DPS to enable polarization rotation from approximately counterclockwise circular polarization to linear polarization. Based on the identical epitaxial layer scheme, all of the PMC, DPS, and DFB laser can be integrated monolithically using only a single step of metalorganic vapor phase epitaxy and two steps of III V material dry etching. For the DFB-PMC device, a high TE to TM polarization conversion efficiency 98% over a wide range of DFB injection currents is reported at 1555 nm wavelength. For the DFB-PMC-DPS device, a 60 degree rotation of the Stokes vector was obtained on the Poincar\'e sphere with a range of bias voltage from 0 V to -4.0 V at IDFB is 170 mA.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Light-matter coupling strength and optical loss are two key physical quantities in cavity quantum electrodynamics (cQED), and their interplay determines whether light-matter hybrid states can be formed or not in chemical systems. In this study, by using macroscopic quantum electrodynamics (mQED) combined with a pseudomode approach, we present a simple but accurate method which allows us to quickly estimate the light-matter coupling strength and optical loss without free parameters. Moreover, for a molecular emitter coupled with photonic modes (including cavity modes and plasmon polartion modes), we analytically and numerically prove that the dynamics derived from the mQED-based wavefunction approach is mathematically equivalent to the dynamics governed by the cQED-based Lindblad master equation when the Purcell factor behaves like Lorentzians.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： One of the fundamental challenges in nanophotonics is to gain full control over nanoscale optical elements. The precise spatiotemporal arrangement determines their interactions and collective behavior. To this end, DNA nanotechnology is employed as an unprecedented tool to create nanophotonic devices with excellent spatial addressability and temporal programmability. However, most of the current DNA-assembled nanophotonic devices can only reconfigure among random or very few defined states. Here, we demonstrate a DNA-assembled rotary plasmonic nanoclock. In this system, a rotor gold nanorod can carry out directional and reversible 360 degree rotation with respect to a stator gold nanorod, transitioning among 16 well-defined configurations powered by DNA fuels. The full-turn rotation process is monitored by optical spectroscopy in real time. We further demonstrate autonomous rotation of the plasmonic nanoclock powered by DNAzyme-RNA interactions. Such assembly approaches pave a viable route towards advanced nanophotonic systems entirely from the bottom-up.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： We study the geometric response of three-dimensional non-Hermitian crystalline systems with nontrivial point-gap topology. For systems with fourfold rotation symmetry, we show that in the presence of disclination lines with a total Frank angle which is an integer multiple of $2\pi$, there can be nontrivial one-dimensional point-gap topology along the direction of the disclination lines. This results in disclination-induced non-Hermitian skin effects. By doubling a non-Hermitian Hamiltonian to a Hermitian three-dimensional chiral topological insulator, we show that the disclination-induced skin modes are zero modes of the effective surface Dirac fermion(s) in the presence of a pseudomagnetic flux induced by disclinations. Furthermore, we find that our results have a field theoretic description, and the corresponding geometric response actions (e.g., the Euclidean Wen-Zee action) enrich the topological field theory of non-Hermitian systems.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Lee-Huang-Yang (LHY) fluids are an exotic quantum matter dominated purely by quantum fluctuations. Recently, the three-dimensional LHY fluids were observed in ultracold atoms experiments, while their low-dimensional counterparts have not been well known. Herein, based on the Gross-Pitaevskii equation of one-dimensional LHY quantum fluids in two-component Bose-Einstein condensates, we reveal analytically and numerically the formation, properties, and dynamics of matter-wave structures therein. Considering a harmonic trap, approximate analytical results are obtained based on variational approximation, and higher-order nonlinear localized modes with nonzero nodes are constructed numerically. Stability regions of all the LHY nonlinear localized modes are identified by linear-stability analysis and direct perturbed numerical simulations. Movements and oscillations of single localized mode, and collisions between two modes, under the influence of different initial kicks are also studied in dynamical evolutions. The predicted results are available to quantum-gas experiments, providing a new insight into LHY physics in low-dimensional settings.
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