We report on the theoretical and experimental investigations of the transition of a typical quantum system with mixed regular-integrable classical dynamics to one with violated time-reversal(T)invariance.The measureme...We report on the theoretical and experimental investigations of the transition of a typical quantum system with mixed regular-integrable classical dynamics to one with violated time-reversal(T)invariance.The measurements are performed with a flat superconducting microwave resonator with circular shape in which chaoticity is induced by using either long antennas or inserting two circular disks into the cavity,and by magnetizing a ferrite disk placed at its center,which leads to violation of T invariance.We propose an extension of the Rosenzweig-Porter(RP)model,which interpolates between mixed regular-chaotic instead of integrable dynamics and fully chaotic dynamics with violated T-invariance,and derive a Wigner-surmise like analytical expression for the corresponding nearest-neighbor spacing distribution.We propose a procedure involving this result and those for the RP model to determine the size of T-invariance violation and chaoticity and validate it employing the experimental eigenfrequency spectra.展开更多
The flourishing of topological photonics in the last decade was achieved mainly due to developments in linear topological photonic structures.However,when nonlinearity is introduced,many intriguing questions arise.For...The flourishing of topological photonics in the last decade was achieved mainly due to developments in linear topological photonic structures.However,when nonlinearity is introduced,many intriguing questions arise.For example,are there universal fingerprints of the underlying topology when modes are coupled by nonlinearity,and what can happen to topological invariants during nonlinear propagation?To explore these questions,we experimentally demonstrate nonlinearity-induced coupling of light into topologically protected edge states using a photonic platform and develop a general theoretical framework for interpreting the mode-coupling dynamics in nonlinear topological systems.Performed on laser-written photonic Su-Schrieffer-Heeger lattices,our experiments show the nonlinear coupling of light into a nontrivial edge or interface defect channel that is otherwise not permissible due to topological protection.Our theory explains all the observations well.Furthermore,we introduce the concepts of inherited and emergent nonlinear topological phenomena as well as a protocol capable of revealing the interplay of nonlinearity and topology.These concepts are applicable to other nonlinear topological systems,both in higher dimensions and beyond our photonic platform.展开更多
Understanding inter-site mutual mode interaction in coupled physical systems is essential to comprehend large compound systems,as this local interaction determines the successive multiple inter-site energy transfer ef...Understanding inter-site mutual mode interaction in coupled physical systems is essential to comprehend large compound systems,as this local interaction determines the successive multiple inter-site energy transfer efficiencies.In the present study,we demonstrate that only the non-Hermitian coupling can correctly account for the light transfer between two coupled optical cavities.We also reveal that the non-Hermitian coupling effect becomes crucial as the system dimension decreases.Our results provide important insight for handling general-coupled devices in the subwavelength regime.展开更多
The Hofstadter energy spectrum of twisted bilayer graphene(TBG)is found to have recursive higher-order topological properties.We demonstrate that higher-order topological insulator(HOTI)phases,characterized by localiz...The Hofstadter energy spectrum of twisted bilayer graphene(TBG)is found to have recursive higher-order topological properties.We demonstrate that higher-order topological insulator(HOTI)phases,characterized by localized corner states,occur as replicas of the original HOTIs to fulfill the self-similarity of the Hofstadter spectrum.We show the existence of exact flux translational symmetry in TBG at all commensurate angles.Based on this result,we identify that the original HOTI phase at zero flux is re-entrant at a half-flux periodicity,where the effective twofold rotation is preserved.In addition,numerous replicas of the original HOTIs are found for fluxes without protecting symmetries.Like the original HOTIs,replica HOTIs feature both localized corner states and edge-localized real-space topological markers.The replica HOTIs originate from the different interaction scales,namely,intralayer and interlayer couplings,in TBG.The topological aspect of Hofstadter butterflies revealed in our results highlights symmetry-protected topology in quantum fractals.展开更多
Engineering of the orbital angular momentum(OAM)of light due to interaction with photonic lattices reveals rich physics and motivates potential applications.We report the experimental creation of regularly distributed...Engineering of the orbital angular momentum(OAM)of light due to interaction with photonic lattices reveals rich physics and motivates potential applications.We report the experimental creation of regularly distributed quantized vortex arrays in momentum space by probing the honeycomb and hexagonal photonic lattices with a single focused Gaussian beam.For the honeycomb lattice,the vortices are associated with Dirac points.However,we show that the resulting spatial patterns of vortices are strongly defined by the symmetry of the wave packet evolving in the photonic lattices and not by their topological properties.Our findings reveal the underlying physics by connecting the symmetry and OAM conversion and provide a simple and efficient method to create regularly distributed multiple vortices from unstructured light.展开更多
The moiré superlattice of misaligned atomic bilayers paves the way for designing a new class of materials with wide tunability.In this work,we propose a photonic analog of the moiré superlattice based on die...The moiré superlattice of misaligned atomic bilayers paves the way for designing a new class of materials with wide tunability.In this work,we propose a photonic analog of the moiré superlattice based on dielectric resonator quasi-atoms.In sharp contrast to van der Waals materials with weak interlayer coupling,we realize the strong coupling regime in a moiré superlattice,characterized by cascades of robust flat bands at large twist-angles.Surprisingly,we find that these flat bands are characterized by a non-trivial band topology,the origin of which is the moiré pattern of the resonator arrangement.The physical manifestation of the flat band topology is a robust one-dimensional conducting channel on edge,protected by the reflection symmetry of the moiré superlattice.By explicitly breaking the underlying reflection symmetry on the boundary terminations,we show that the first-order topological edge modes naturally deform into higher-order topological corner modes.Our work pioneers the physics of topological phases in the designable platform of photonic moiré superlattices beyond the weakly coupled regime.展开更多
We predict the preservation of temporal indistinguishability of photons propagating through helical coupled-resonator optical waveguides(H-CROWs).H-CROWs exhibit a pseudospin-momentum locked dispersion,which we show s...We predict the preservation of temporal indistinguishability of photons propagating through helical coupled-resonator optical waveguides(H-CROWs).H-CROWs exhibit a pseudospin-momentum locked dispersion,which we show suppresscs on-site disorder-induced backscattering and group velocity fluctuations.We simulate numerically the propagation of two-photon wave packets,demonstrating that they exhibit almost perfect Hong-Ou-Mandel dip visibility and then can preserve their quantum coherence even in the presence of moderate disorder,in contrast with regular CROws,which are highly sensitive to disorder.As indistinguishability is the most fundamental resource of quantum information processing,H-CROWs may find applications for the implementation of robust optical links and delay lines in the emerging quantum photonic communication and computational platforms.展开更多
Universality class of wave chaos emerges in many areas of science,such as molecular dynamics,optics,and network theory.In this work,we generalize the wave chaos theory to cavity lattice systems by discovering the intr...Universality class of wave chaos emerges in many areas of science,such as molecular dynamics,optics,and network theory.In this work,we generalize the wave chaos theory to cavity lattice systems by discovering the intrinsic coupling of the crystal momentum to the internal cavity dynamics.The cavity-momentum locking substitutes the role of the deformed boundary shape in the ordinary single microcavity problem,providing a new platform for the in situ study of microcavity light dynamics.The transmutation of wave chaos in periodic lattices leads to a phase space reconfiguration that induces a dynamical localization transition.The degenerate scar-mode spinors hybridize and non-trivially localize around regular islands in phase space.In addition,we find that the momentum coupling becomes maximal at the Brillouin zone boundary,so the intercavity chaotic modes coupling and wave confinement are significantly altered.Our work pioneers the study of intertwining wave chaos in periodic systems and provide useful applications in light dynamics control.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11775100,12247101,and 11961131009)the financial support from the China Scholarship Council(Grant No.CSC202306180087)the financial support from the Institute for Basic Science in Korea(Grant No.IBS-R024-D1)。
文摘We report on the theoretical and experimental investigations of the transition of a typical quantum system with mixed regular-integrable classical dynamics to one with violated time-reversal(T)invariance.The measurements are performed with a flat superconducting microwave resonator with circular shape in which chaoticity is induced by using either long antennas or inserting two circular disks into the cavity,and by magnetizing a ferrite disk placed at its center,which leads to violation of T invariance.We propose an extension of the Rosenzweig-Porter(RP)model,which interpolates between mixed regular-chaotic instead of integrable dynamics and fully chaotic dynamics with violated T-invariance,and derive a Wigner-surmise like analytical expression for the corresponding nearest-neighbor spacing distribution.We propose a procedure involving this result and those for the RP model to determine the size of T-invariance violation and chaoticity and validate it employing the experimental eigenfrequency spectra.
基金supported by the National Key R&D Program of China under Grant No.2017YFA0303800the National Natural Science Foundation(11922408,91750204,11674180),PCSIRT+5 种基金the 111 Project(No.B07013)in Chinasupport in part by the Croatian Science Foundation Grant No.IP-2016-06-5885 SynthMagIAthe QuantiXLie Center of Excellence,a project co-financed by the Croatian Government and European Union through the European Regional Development Fund-the Competitiveness and Cohesion Operational Programme(Grant KK.01.1.1.01.0004)supported by the Australian Research Council(DE19010043)supported by the Institute for Basic Science in Korea(IBS-R024-Y1)support from the Russian Foundation for Basic Research(grant No.19-52-12053).
文摘The flourishing of topological photonics in the last decade was achieved mainly due to developments in linear topological photonic structures.However,when nonlinearity is introduced,many intriguing questions arise.For example,are there universal fingerprints of the underlying topology when modes are coupled by nonlinearity,and what can happen to topological invariants during nonlinear propagation?To explore these questions,we experimentally demonstrate nonlinearity-induced coupling of light into topologically protected edge states using a photonic platform and develop a general theoretical framework for interpreting the mode-coupling dynamics in nonlinear topological systems.Performed on laser-written photonic Su-Schrieffer-Heeger lattices,our experiments show the nonlinear coupling of light into a nontrivial edge or interface defect channel that is otherwise not permissible due to topological protection.Our theory explains all the observations well.Furthermore,we introduce the concepts of inherited and emergent nonlinear topological phenomena as well as a protocol capable of revealing the interplay of nonlinearity and topology.These concepts are applicable to other nonlinear topological systems,both in higher dimensions and beyond our photonic platform.
基金National Research Foundation of Korea(NRF)(2021R1A2C1095623)Institute for Basic Science(IBS-R024-D1).
文摘Understanding inter-site mutual mode interaction in coupled physical systems is essential to comprehend large compound systems,as this local interaction determines the successive multiple inter-site energy transfer efficiencies.In the present study,we demonstrate that only the non-Hermitian coupling can correctly account for the light transfer between two coupled optical cavities.We also reveal that the non-Hermitian coupling effect becomes crucial as the system dimension decreases.Our results provide important insight for handling general-coupled devices in the subwavelength regime.
基金This work was supported by the Korean National Research Foundation(NRF)Basic Research Laboratory(NRF-2020R1A4A307970713)the NRF Grant numbers(NRF-2021R1A2C101387112 and NRF-2021M3H3A1038085)+1 种基金This work was also supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(RS-2023-00252085,RS-2023-00218998)The computational resource was provided by the Korea Institute of Science and Technology Information(KISTI)(KSC-2020-CRE-0108).
文摘The Hofstadter energy spectrum of twisted bilayer graphene(TBG)is found to have recursive higher-order topological properties.We demonstrate that higher-order topological insulator(HOTI)phases,characterized by localized corner states,occur as replicas of the original HOTIs to fulfill the self-similarity of the Hofstadter spectrum.We show the existence of exact flux translational symmetry in TBG at all commensurate angles.Based on this result,we identify that the original HOTI phase at zero flux is re-entrant at a half-flux periodicity,where the effective twofold rotation is preserved.In addition,numerous replicas of the original HOTIs are found for fluxes without protecting symmetries.Like the original HOTIs,replica HOTIs feature both localized corner states and edge-localized real-space topological markers.The replica HOTIs originate from the different interaction scales,namely,intralayer and interlayer couplings,in TBG.The topological aspect of Hofstadter butterflies revealed in our results highlights symmetry-protected topology in quantum fractals.
基金supported by the National Key R&D Program of China(Grant Nos.2018YFA0307500 and 2023YFA1407100)the Key Scientific and Technological Innovation Team of Shaanxi Province(Grant No.2021TD-56)+7 种基金the National Natural Science Foundation of China(Grant Nos.12074303,62022066,12074306,and 11804267)the IBS Young Scientist Fellowship(Grant No.IBS-R024-Y3)the Basis Foundation(Grant No.21-1-3-30-1)the support of the European Union’s Horizon 2020 program,through an FET Open research and innovation action(Grant No.964770)(Topo Light)he ANR projects Labex Ga NEXT(Grant No.ANR-11-LABX0014)“NEWAVE”(Grant No.ANR-21-CE24-0019)the ANR program“Investissements d’Avenir”through the IDEX-ISITE initiative 16-IDEX-0001(Grant No.CAP 20-25)support by the Russian Science Foundation(Grant No.22-12-00144)
文摘Engineering of the orbital angular momentum(OAM)of light due to interaction with photonic lattices reveals rich physics and motivates potential applications.We report the experimental creation of regularly distributed quantized vortex arrays in momentum space by probing the honeycomb and hexagonal photonic lattices with a single focused Gaussian beam.For the honeycomb lattice,the vortices are associated with Dirac points.However,we show that the resulting spatial patterns of vortices are strongly defined by the symmetry of the wave packet evolving in the photonic lattices and not by their topological properties.Our findings reveal the underlying physics by connecting the symmetry and OAM conversion and provide a simple and efficient method to create regularly distributed multiple vortices from unstructured light.
基金We acknowledge financial support from the Institute for Basic Science(IBS)in the Republic of Korea through the project IBS-RO24-D1This work is also supported by Korea Institute for Advanced Study(KIAS).
文摘The moiré superlattice of misaligned atomic bilayers paves the way for designing a new class of materials with wide tunability.In this work,we propose a photonic analog of the moiré superlattice based on dielectric resonator quasi-atoms.In sharp contrast to van der Waals materials with weak interlayer coupling,we realize the strong coupling regime in a moiré superlattice,characterized by cascades of robust flat bands at large twist-angles.Surprisingly,we find that these flat bands are characterized by a non-trivial band topology,the origin of which is the moiré pattern of the resonator arrangement.The physical manifestation of the flat band topology is a robust one-dimensional conducting channel on edge,protected by the reflection symmetry of the moiré superlattice.By explicitly breaking the underlying reflection symmetry on the boundary terminations,we show that the first-order topological edge modes naturally deform into higher-order topological corner modes.Our work pioneers the physics of topological phases in the designable platform of photonic moiré superlattices beyond the weakly coupled regime.
基金Institute for Basic Science(IBS-R024-Y1,IBS-R024-D1)Australian Research Council(DP190100277).
文摘We predict the preservation of temporal indistinguishability of photons propagating through helical coupled-resonator optical waveguides(H-CROWs).H-CROWs exhibit a pseudospin-momentum locked dispersion,which we show suppresscs on-site disorder-induced backscattering and group velocity fluctuations.We simulate numerically the propagation of two-photon wave packets,demonstrating that they exhibit almost perfect Hong-Ou-Mandel dip visibility and then can preserve their quantum coherence even in the presence of moderate disorder,in contrast with regular CROws,which are highly sensitive to disorder.As indistinguishability is the most fundamental resource of quantum information processing,H-CROWs may find applications for the implementation of robust optical links and delay lines in the emerging quantum photonic communication and computational platforms.
基金We acknowledge financial support from the Institute for Basic Science(IBS)in the Republic of Korea through the project IBS-R024-D1This work is also supported by the research fund of Hanyang University(HY-202300000001149)。
文摘Universality class of wave chaos emerges in many areas of science,such as molecular dynamics,optics,and network theory.In this work,we generalize the wave chaos theory to cavity lattice systems by discovering the intrinsic coupling of the crystal momentum to the internal cavity dynamics.The cavity-momentum locking substitutes the role of the deformed boundary shape in the ordinary single microcavity problem,providing a new platform for the in situ study of microcavity light dynamics.The transmutation of wave chaos in periodic lattices leads to a phase space reconfiguration that induces a dynamical localization transition.The degenerate scar-mode spinors hybridize and non-trivially localize around regular islands in phase space.In addition,we find that the momentum coupling becomes maximal at the Brillouin zone boundary,so the intercavity chaotic modes coupling and wave confinement are significantly altered.Our work pioneers the study of intertwining wave chaos in periodic systems and provide useful applications in light dynamics control.
