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Experimental quantum secure network with digital signatures and encryption

National Science Review 2023年第4期10卷 86-96页

作者： Hua-Lei Yin Yao Fu Chen-Long Li Chen-Xun Weng Bing-Hong Li Jie Gu Yu-Shuo Lu Shan Huang Zeng-Bing Chen National Laboratory of Solid State Microstructures School of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University MatricTime Digital Technology Co.Ltd.

Cryptography promises four information security objectives, namely, confidentiality, integrity, authenticity and non-repudiation, to support trillions of transactions annually in the digital economy. Efficient digital signatures, ensuring integrity, authenticity and non-repudiation of data with information-theoretical security are highly urgent and intractable open problems in cryptography. Here, we propose a high-efficiency quantum digital signature（QDS） protocol using asymmetric quantum keys acquired via secret sharing, one-time universal2hashing and a one-time pad. We just need to use a 384-bit key to sign documents of lengths up to 264with a security bound of 10-19. If a one-megabit document is signed, the signature efficiency is improved by more than 10～8 times compared with previous QDS ***, we build the first all-in-one quantum secure network integrating information-theoretically secure communication, digital signatures, secret sharing and conference key agreement and experimentally demonstrate this signature efficiency advantage. Our work completes the cryptography toolbox of the four information security objectives.

关键词： quantum digital signature information-theoretical security secret sharing one-time universal2 hashing cryptography toolbox

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Fast selective edge-enhanced imaging with topological chiral lamellar superstructures

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National Science Review 2024年第11期11卷 215-224页

作者： Wen Chen Dong Zhu Si-Jia Liu Yi-Heng Zhang Lin Zhu Chao-Yi Li Shi-Jun Ge Peng Chen Wan-Long Zhang Xiao-Cong Yuan Yan-Qing Lu National Laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and Manipulation College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced MicrostructuresNanjing University Nanophotonics Research Center Institute of Microscale OptoelectronicsShenzhen University

Edge detection is a fundamental operation for feature extraction in image processing. The all-optical method has aroused growing interest owing to its ultra-fast speed, low energy consumption and parallel computation. However, current optical edge detection methods are generally limited to static devices and fixed functionality. Herein, we propose a fast-switchable scheme based on a ferroelectric liquid crystal topological structure. The self-assembled chiral lamellar superstructure, directed by the azimuthally variant photo-alignment agent, can be dynamically controlled by the polarity of the external electric field and respectively generates the vector beams with nearly orthogonal polarization distribution. Even after thousands of cycles, the horizontal and vertical edges of the object are selectively enhanced with an ultra-fast switching time of ～57 μs. Broadband edge-enhanced imaging is efficiently demonstrated. This work extends the ingenious building of topological heliconical superstructures and offers an important glimpse into their potential in the emerging frontiers of optical computing for artificial intelligence.

关键词： edge detection ferroelectric liquid crystal topological structure vector beam fast response

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Realization of highly asymmetric hydrogenated graphene in the van der Waals confined space

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National Science Review 2025年第4期12卷 318-327页

作者： Xianlei Huang Hang Zheng Weilin Liu Li Zhu Guowen Yuan Jie Xu Kaiyuan Wang Lei Wang Shao-Chun Li Libo Gao National Laboratory of Solid State Microstructures Jiangsu Key Laboratory for NanotechnologySchool of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing University Anhui Provincial Key Laboratory of Magnetic Functional Materials and Devices School of Materials Science and Engineering Anhui University

The van der Waals(vdW) confined space provides a distinct environment from free space,enabling the production of two-dimensional Janus materials,like highly asymmetric hydrogenated graphene(AH-Gr).Here,we develop a vdW confined space assisted hydrogenation method to produce *** confined space between graphene and the substrate aggregates hydrogen radicals,making the bottom-side of graphene more prone to *** dense and homogeneous confined spaces between adjacent vdW crystals promote rapid and uniform distribution of carbon-hydrogen(C—H) *** hydrogen-to-carbon atomic(H/C) ratios can be quantitatively controlled by adjusting the permeated proton *** AH-Gr,regardless of H/C ratios,remain *** spatial distributions of C—H bonds significantly influence the electrical and magnetic properties of *** hydrogenation transforms graphene from a semi-metal to a semiconductor,suppresses the quantum Hall effect,and reduces the phase coherence *** study provides new insights into the preparation and characteristics of hydrogenated graphene,broadening the applications of vdW confined space.

关键词： van der Waals confined space highly asymmetric hydrogenated graphene proton

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Correlation-Pattern-Based Orbital Angular Momentum Entanglement Measurement Through Neural Networks

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Chinese Physics Letters 2025年第3期42卷 23-28页

作者： Jiaxian Zhao Zhifeng Liu Chenghou Tu Yongnan Li Hui-Tian Wang Key Laboratory of Weak-Light Nonlinear Photonics and School of Physics Nankai UniversityTianjin 300071China National Laboratory of Solid State Microstructures School of Physicsand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

High-dimensional(HD)entanglement of photonic orbital angular momentum(OAM)is pivotal for advancing quantum communication and information processing,but its characterization remains significant challenges due to the complexity of quantum state tomography and experimental limitations such as low photon counts caused by ***,we propose a pre-trained physics-informed neural network(PTPINN)framework that enables efficient and rapid reconstruction of HD-OAM entangled states under low photon *** results show that the fidelity of five-dimensional OAM entanglement reaches F=0.958±0.010 even with an exposure time as short as 50 *** highlights the capability of PTPINN to achieve high-precision quantum state reconstruction with limited photons,owing to its innovative designs,thus overcoming the reliance on high photon counts typical of traditional *** method provides a practical and scalable solution for high-fidelity characterization of HD-OAM entanglement in environments with low photon numbers and high noise,paving the way for robust long-distance quantum information transmission.

关键词： quantum momentum enable

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Manipulating optical and electronic properties through interfacial ferroelectricity

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Chinese Physics B 2025年第1期34卷 2-12页

作者： Yulu Liu Gan Liu Xiaoxiang Xi National Laboratory of Solid State Microstructures and Department of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China Jiangsu Physical Science Research Center Nanjing 210093China

Interfacial ferroelectricity is a recently established mechanism for generating spontaneous reversible electric polarization,arising from the charge transfer between stacked van der Waals layered atomic *** has been realized in both naturally formed multilayer crystals and moiré*** to the large number of material choices and combinations,this approach is highly versatile,greatly expanding the scope of ultrathin ferroelectrics.A key advantage of interfacial ferroelectricity is its potential to couple with preexisting properties of the constituent layers,enabling their electrical manipulation through ferroelectric switching and paving the way for advanced device *** review article summarizes recent experimental progress in interfacial ferroelectricity,with an emphasis on its coupling with a variety of electronic *** introducing the underlying mechanism of interfacial ferroelectricity and the range of material systems discovered to date,we highlight selected examples showcasing ferroelectric control of excitonic optical properties,Berry curvature effects,and *** also discuss the challenges and opportunities that await further studies in this field.

关键词： interfacial ferroelectricity sliding ferroelectricity moir´e ferroelectricity

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Quantum Neural Network for Quantum Neural Computing

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Research 2024年第1期2023卷 71-80页

作者： Min-Gang Zhou Zhi-Ping Liu Hua-Lei Yin Chen-Long Li Tong-Kai Xu Zeng-Bing Chen National Laboratory of Solid State Microstructures School of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China MatricTime Digital Technology Co.Ltd. Nanjing 211899China

Neural networks have achieved impressive breakthroughs in both industry and *** to effectively develop neural networks on quantum computing devices is a challenging open ***,we propose a new quantum neural network model for quantum neural computing using(classically controlled)single-qubit operations and measurements on real-world quantum systems with naturally occurring environment-induced decoherence,which greatly reduces the difficulties of physical *** model circumvents the problem that the state-space size grows exponentially with the number of neurons,thereby greatly reducing memory requirements and allowing for fast optimization with traditional optimization *** benchmark our model for handwritten digit recognition and other nonlinear classification *** results show that our model has an amazing nonlinear classification ability and robustness to ***,our model allows quantum computing to be applied in a wider context and inspires the earlier development of a quantum neural computer than standard quantum computers.

关键词： quantum thereby breakthrough

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Anomalous temperature dependence of uniaxial magnetocrystalline anisotropy in the van der Waals ferromagnet Fe3GeTe2

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Physical Review B 2024年第6期109卷 L060404-L060404页

作者： Jiawei Liu Liang Zhou Shuilin Li Enyue Zhao Nujiang Tang National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced Microstructures and Jiangsu Provincial Key Laboratory for Nanotechnology Nanjing University Nanjing 210093 China Songshan Lake Materials Laboratory Dongguan 523808 China

Uniaxial magnetocrystalline anisotropy (UMA) is vital for fundamental research, such as maintaining two-dimensional ferromagnetic order and realizing topological phases. However, in most cases, UMA rapidly decreases with increasing temperature and finally vanishes approaching the Curie temperature (TC). The increasing UMA with increasing temperature is very rare in almost all traditional ferromagnetic materials and in emerging van der Waals (vdW) ferromagnets, which generally have relatively low TC. Here, we experimentally unveil the anomalous temperature dependence of the UMA constant Ku1(T) in the vdW ferromagnet Fe3GeTe2. Surprisingly, the Ku1(T) first anomalously increases and then slowly decreases. We found that the anomalous Ku1(T) can be perfectly fitted by Carr's model. Further analysis and temperature-dependent x-ray diffraction measurements suggest that the partial localization of 3d electrons and considerable lattice expansion are crucial for anomalous Ku1(T). We propose that the complex competition between the two-ion mechanism and the itinerant-electron mechanism leads to the anomalous behavior of Ku1(T) in Fe3GeTe2. Our findings from this unusual case help deepen the understanding of the temperature dependence of UMA.

关键词： Ferromagnetism Magnetic anisotropy Ferromagnets Layered crystals Crystal growth Magnetization measurements X-ray powder diffraction

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Three-Dirac-fermion approach to unexpected universal gapless surface states in van der Waals magnetic topological insulators

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Science China(Physics,Mechanics & Astronomy) 2023年第9期66卷 79-85页

作者： Dinghui Wang Huaiqiang Wang Dingyu Xing Haijun Zhang National Laboratory of Solid State Microstructures School of PhysicsNanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

Layered van der Waals(vdW) topological materials, especially the recently discovered MnBi_(2)Te_(4)-family magnetic topological insulators(TIs), have aroused great attention. However, there has been a serious debate about whether the surface states are gapped or gapless for antiferromagnetic(AFM) TI MnBi_(2)Te_(4), which is crucial to the prospect of various magnetic topological phenomena. Here, a minimal three-Dirac-fermion approach is developed to generally describe topological surface states of nonmagnetic/magnetic vdW TIs under the modulation of the interlayer vdW gap. In particular, this approach is applied to address the controversial issues concerning the surface states of vdW AFM TIs. Remarkably, topologically protected gapless Dirac-cone surface states are found to arise due to a small expansion of the interlayer vdW gap on the surface, when the Chern number equals zero for the surface ferromagnetic layer;while the surface states remain gapped in all other cases. These results are further confirmed by our first-principles calculations on AFM TI MnBi_(2)Te_(4). The theorectically discovered gapless Dirac-cone states provide a unique mechanism for understanding the puzzle of the experimentally observed gapless surface states in MnBi_(2)Te_(4).This work also provides a promising way for experiments to realize the intrinsic magnetic quantum anomalous Hall efect in MnBi_(2)Te_(4) films with a large energy gap.

关键词： magnetic topological insulator van der Waals gap Dirac-fermion model gapless surface state

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Gate-Tunable Lifshitz Transition of Fermi Arcs and Its Transport Signatures

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Chinese Physics Letters 2023年第9期40卷 71-77页

作者：郑悦陈伟万贤纲邢定钰 National Laboratory of Solid State Microstructures and School of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

One hallmark of Weyl semimetals is the emergence of Fermi arcs(FAs) in surface Brillouin zones, where FAs connect the projected Weyl nodes of opposite chiralities. Unclosed FAs can give rise to various exotic effects that have attracted tremendous research interest. Configurations of FAs are usually thought to be determined fully by the band topology of the bulk states, which seems impossible to manipulate. Here, we show that FAs can be simply modified by a surface gate voltage. Because the penetration length of the surface states depends on the in-plane momentum, a surface gate voltage induces an effective energy dispersion. As a result, a continuous deformation of the surface band can be implemented by tuning the surface gate voltage. In particular, as the saddle point of the surface band meets the Fermi energy, the topological Lifshitz transition takes place for the FAs,during which the Weyl nodes switch their partners connected by the FAs. Accordingly, the magnetic Weyl orbits composed of the FAs on opposite surfaces and chiral Landau bands inside the bulk change their *** show that such an effect can be probed by the transport measurements in a magnetic field, in which the switch-on and switch-off conductances by the surface gate voltage signal the Lifshitz transition. Our work opens a new route for manipulating the FAs by surface gates and exploring novel transport phenomena associated with the topological Lifshitz transition.

关键词： transition Fermi opposite

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Overcoming bandwidth limitations in space-coiled acoustic metamaterials through inclined perforated plate design

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Chinese Physics B 2025年第1期34卷 374-379页

作者： Jixin Liu Fengmin Wu Ting Li Junjun Wang Xinye Zou Dong Zhang Department of Applied Physics School of ScienceHarbin University of Science and TechnologyHarbin 150080China Key Laboratory of Modern Acoustics(MOE) Department of PhysicsCollaborative Innovation Center of Advanced MicrostructureNanjing UniversityNanjing 210093China Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

Traditional space-coiled acoustic metamaterials have been widely used in the fields of low-frequency sound absorption and noise ***,they have limitations in terms of low-frequency absorption bandwidth,and the weak coupling effect under complex coiled structures also limits their *** this work,we introduce the composite structure changing the characteristic impedance of acoustic metamaterials to enhance the coupling ***,the perforated plates with inclined design instead of traditional partitions greatly improve the sound *** model and method designed in this paper show significant innovation in enhancing low-frequency absorption performance.

关键词： metamaterials composite structure over-damped modes coupling sound absorption

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