Flatbands are of significant interest due to their potential for strong energy confinement and their ability to facilitate strongly correlated physics such as unconventional superconductivity and fractional quantum Ha...Flatbands are of significant interest due to their potential for strong energy confinement and their ability to facilitate strongly correlated physics such as unconventional superconductivity and fractional quantum Hall states.When topology is incorporated into flatband systems,it further enhances flatband mode robustness against perturbations.We present the first realization of doubly degenerate topological flatbands of edge states in chiral-symmetric strained graphene.The flatband degeneracy stems from the merging of Dirac points,achieved by tuning the coupling ratios in a honeycomb lattice with newly discovered twig boundary conditions.The topology of these modes is characterized by the nontrivial winding number,which ensures their robustness against disorder.Experimentally,two types of topological edge states are observed in a strained photonic graphene lattice,consistent with numerical simulations.Moreover,the degeneracy of the topological flatbands doubles the density of states for zero-energy modes,facilitating the formation of compact edge states and providing greater control over edge states and light confinement.Our findings underscore the interplay among lattice geometry,symmetry,and topology in shaping doubly degenerate topological flatbands.This work opens new possibilities for advancements in correlated effects,nonlinear optical phenomena,and efficient energy transfer in materials science,photonic crystals,and quantum devices.展开更多
Zero-energy modes localized at the ends of one-dimensional(1D)wires hold great potential as qubits for fault-tolerant quantum computing.However,all the candidates known to date exhibit a wave function that decays expo...Zero-energy modes localized at the ends of one-dimensional(1D)wires hold great potential as qubits for fault-tolerant quantum computing.However,all the candidates known to date exhibit a wave function that decays exponentially into the bulk and hybridizes with other nearby zero-modes,thus hampering their use for braiding operations.Here,we show that a quasi-1D diamond-necklace chain exhibits an unforeseen type of robust boundary state,namely compact localized zero-energy modes that do not decay into the bulk.We find that this state emerges due to the presence of a latent symmetry in the system.We experimentally realize the diamond-necklace chain in an electronic quantum simulator setup.展开更多
In the artificial intelligence-driven modern wireless communication system,antennas are required to be reconfigurable in terms of size according to changing application scenarios.However,conventional antennas with con...In the artificial intelligence-driven modern wireless communication system,antennas are required to be reconfigurable in terms of size according to changing application scenarios.However,conventional antennas with constant phase distributions cannot achieve enhanced gains in different reconfigurable sizes.In this paper,we propose a mechanically reconfigurable radiation array(RRA)based on miniaturized elements and a mechanically reconfigurable system to obtain gain-enhanced antennas in compact and deployed states.A five-element RRA with a phase-reconfigurable center element is designed and analyzed theoretically.The experimental sample has been fabricated,driven by a deployable frame with only one degree of freedom to realize the size and phase distribution reconfiguration simultaneously to validate the enhanced gains of RRA.The proposed RRA can be tessellated into larger arrays to achieve higher gains in other frequency regimes,such as terahertz or photonics applications with nanometer fabrication technology.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFA1404800)the National Natural Science Foundation of China(Grant Nos.12134006,12274242+2 种基金12474387)the Natural Science Foundation of Tianjin(Grant No.21JCJQJC00050)the 111 Project in China(Grant No.B23045)。
文摘Flatbands are of significant interest due to their potential for strong energy confinement and their ability to facilitate strongly correlated physics such as unconventional superconductivity and fractional quantum Hall states.When topology is incorporated into flatband systems,it further enhances flatband mode robustness against perturbations.We present the first realization of doubly degenerate topological flatbands of edge states in chiral-symmetric strained graphene.The flatband degeneracy stems from the merging of Dirac points,achieved by tuning the coupling ratios in a honeycomb lattice with newly discovered twig boundary conditions.The topology of these modes is characterized by the nontrivial winding number,which ensures their robustness against disorder.Experimentally,two types of topological edge states are observed in a strained photonic graphene lattice,consistent with numerical simulations.Moreover,the degeneracy of the topological flatbands doubles the density of states for zero-energy modes,facilitating the formation of compact edge states and providing greater control over edge states and light confinement.Our findings underscore the interplay among lattice geometry,symmetry,and topology in shaping doubly degenerate topological flatbands.This work opens new possibilities for advancements in correlated effects,nonlinear optical phenomena,and efficient energy transfer in materials science,photonic crystals,and quantum devices.
基金financial support from the European Research Council(Horizon 2020“FRACTAL”,865570)the Dutch Research Council(grant 16PR3245)+2 种基金the research program“Materials for the Quantum Age”(QuMat)for financial supportThis program(registration number 024.005.006)is part of the Gravitation program financed by the Dutch Ministry of Education,Culture and Science(OCW)funding provided by Shanghai Jiao Tong University.
文摘Zero-energy modes localized at the ends of one-dimensional(1D)wires hold great potential as qubits for fault-tolerant quantum computing.However,all the candidates known to date exhibit a wave function that decays exponentially into the bulk and hybridizes with other nearby zero-modes,thus hampering their use for braiding operations.Here,we show that a quasi-1D diamond-necklace chain exhibits an unforeseen type of robust boundary state,namely compact localized zero-energy modes that do not decay into the bulk.We find that this state emerges due to the presence of a latent symmetry in the system.We experimentally realize the diamond-necklace chain in an electronic quantum simulator setup.
文摘In the artificial intelligence-driven modern wireless communication system,antennas are required to be reconfigurable in terms of size according to changing application scenarios.However,conventional antennas with constant phase distributions cannot achieve enhanced gains in different reconfigurable sizes.In this paper,we propose a mechanically reconfigurable radiation array(RRA)based on miniaturized elements and a mechanically reconfigurable system to obtain gain-enhanced antennas in compact and deployed states.A five-element RRA with a phase-reconfigurable center element is designed and analyzed theoretically.The experimental sample has been fabricated,driven by a deployable frame with only one degree of freedom to realize the size and phase distribution reconfiguration simultaneously to validate the enhanced gains of RRA.The proposed RRA can be tessellated into larger arrays to achieve higher gains in other frequency regimes,such as terahertz or photonics applications with nanometer fabrication technology.
基金supported by the Ministry of Science and Technology of China(2022YFA1403901)the National Natural Science Foundation of China(11888101 and 12174428)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB28000000)the Chinese Academy of Sciences through the Youth Innovation Promotion Association(2022YSBR-048)。
