Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 126
Filtrar
1.
Nature ; 589(7842): 381-385, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33473227

RESUMO

Most natural and artificial materials have crystalline structures from which abundant topological phases emerge1-6. However, the bulk-edge correspondence-which has been widely used in experiments to determine the band topology from edge properties-is inadequate in discerning various topological crystalline phases7-16, leading to challenges in the experimental classification of the large family of topological crystalline materials4-6. It has been theoretically predicted that disclinations-ubiquitous crystallographic defects-can provide an effective probe of crystalline topology beyond edges17-19, but this has not yet been confirmed in experiments. Here we report an experimental demonstration of bulk-disclination correspondence, which manifests as fractional spectral charge and robust bound states at the disclinations. The fractional disclination charge originates from the symmetry-protected bulk charge patterns-a fundamental property of many topological crystalline insulators (TCIs). Furthermore, the robust bound states at disclinations emerge as a secondary, but directly observable, property of TCIs. Using reconfigurable photonic crystals as photonic TCIs with higher-order topology, we observe these hallmark features via pump-probe and near-field detection measurements. It is shown that both the fractional charge and the localized states emerge at the disclination in the TCI phase but vanish in the trivial phase. This experimental demonstration of bulk-disclination correspondence reveals a fundamental phenomenon and a paradigm for exploring topological materials.

2.
Proc Natl Acad Sci U S A ; 120(3): e2217068120, 2023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-36634140

RESUMO

Thermal metamaterials provide rich control of heat transport which is becoming the foundation of cutting-edge applications ranging from chip cooling to biomedical. However, due to the fundamental laws of physics, the manipulation of heat is much more constrained in conventional thermal metamaterials where effective heat conduction with Onsager reciprocity dominates. Here, through the inclusion of thermal convection and breaking the Onsager reciprocity, we unveil a regime in thermal metamaterials and transformation thermotics that goes beyond effective heat conduction. By designing a liquid-solid hybrid thermal metamaterial, we demonstrate a continuous switch from thermal cloaking to thermal concentration in one device with external tuning. Underlying such a switch is a topology transition in the virtual space of the thermotic transformation which is achieved by tuning the liquid flow via external control. These findings illustrate the extraordinary heat transport in complex multicomponent thermal metamaterials and pave the way toward an unprecedented regime of heat manipulation.


Assuntos
Temperatura Baixa , Convecção , Temperatura Alta , Transição de Fase , Física
3.
Hum Hered ; 89(1): 52-59, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38830343

RESUMO

INTRODUCTION: Recessive mutations in the CAPN3 gene can lead to limb-girdle muscular dystrophy recessive 1 (LGMD R1). Targeted next-generation sequencing facilitates the discovery of new mutations linked with disease, owing to its ability to selectively enrich specific genomic regions. METHODS: We performed targeted next-generation sequencing of all exons of the CAPN3 gene in 4 patients with sporadic limb-girdle muscular dystrophy (LGMD) and further analyzed the effects of the novel identified variant using various software tools. RESULTS: We found 5 variants in CAPN3 gene in 4 patients, c.82_83insC (insertion mutation) and c.1115+2T>C (splicing mutation) are reported for the first time in CAPN3 (NM_000070.2). The bioinformatics analysis indicated that these two novel variants affected CAPN3 transcription as well as translation. DISCUSSION: Our findings reveal previously unreported splicing mutation and insertion mutation in CAPN3 gene, further expanding the pathogenic gene profile of LGMD.


Assuntos
Povo Asiático , Calpaína , Proteínas Musculares , Distrofia Muscular do Cíngulo dos Membros , Humanos , Calpaína/genética , Distrofia Muscular do Cíngulo dos Membros/genética , Proteínas Musculares/genética , Masculino , Feminino , Povo Asiático/genética , Sequenciamento de Nucleotídeos em Larga Escala , Adulto , Mutação/genética , China , Adolescente , Éxons/genética , Adulto Jovem , População do Leste Asiático
4.
J Membr Biol ; 257(1-2): 115-129, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38150051

RESUMO

Lung adenocarcinoma (LUAD) is one of the deadliest malignant tumors worldwide. Transient receptor potential vanilloid (TRPV) channels take pivotal parts in many cancers, but their impact on LUAD remains unexplored. In this study, LUAD samples were classified into two subtypes according to the expression characteristics of TRPV1-6 genes, with LUAD subtype cluster2 exhibiting significantly higher survival rates than cluster1. Subsequently, analysis of differentially expressed genes (DEGs) was performed between cluster1 and cluster2, revealing enrichment of DEGs in channel activity and Ca2+ signaling pathways. We established a protein-protein interaction network based on DEGs and constructed a LUAD prognostic model by using Cox regression analysis based on genes corresponding to 170 protein nodes. The prognostic model demonstrated good predictive ability for patient prognosis, with higher survival rates observed in the low-risk (LR) group. The risk score was validated as an independent prognostic indicator, according to Cox regression analysis. A clinically applicable nomogram was plotted. Immunological analysis indicated that the LR and high-risk (HR) groups had varied proportions of immune cell infiltration. The immunotherapy prediction indicated that LUAD patients in LR group had a greater likelihood to benefit from immune checkpoint blockade therapy. Furthermore, we hypothesized that the expression patterns of feature genes in the LUAD model were related to the sensitivity to lung cancer therapeutic drugs TAS-6417 and Erlotinib. To sum up, our LUAD prognostic model possessed clinical applicability for prognosis and immunotherapy response prediction.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Humanos , Prognóstico , Adenocarcinoma de Pulmão/genética , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética
5.
Int J Mol Sci ; 25(1)2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38203801

RESUMO

The eating and cooking quality (ECQ) directly affects the taste of rice, being closely related to factors such as gelatinization temperature (GT), gel consistency (GC) and amylose content (AC). Mining the quantitative trait loci (QTLs), and gene loci controlling ECQ-related traits is vital. A genome-wide association study on ECQ-related traits was conducted, combining 1.2 million single nucleotide polymorphisms (SNPs) with the phenotypic data of 173 rice accessions. Two QTLs for GT, one for GC and five for AC were identified, of which two were found in previously reported genes, and six were newly found. There were 28 positional candidate genes in the region of qAC11. Based on a linkage disequilibrium (LD) analysis, three candidate genes were screened within the LD region associated with AC. There were significant differences between the haplotypes of LOC_Os11g10170, but no significant differences were found for the other two genes. The qRT-PCR results showed that the gene expression levels in the accessions with high ACs were significantly larger than those in the accessions with low ACs at 35d and 42d after flowering. Hap 2 and Hap 3 of LOC_Os11g10170 reduced the AC by 13.09% and 10.77%, respectively. These results provide a theoretical and material basis for improving the ECQ of rice.


Assuntos
Oryza , Locos de Características Quantitativas , Oryza/genética , Estudo de Associação Genômica Ampla , Amilose , Culinária
6.
Rep Prog Phys ; 86(10)2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37706242

RESUMO

The concept of topological energy bands and their manifestations have been demonstrated in condensed matter systems as a fantastic paradigm toward unprecedented physical phenomena and properties that are robust against disorders. Recent years, this paradigm was extended to phononic metamaterials (including mechanical and acoustic metamaterials), giving rise to the discovery of remarkable phenomena that were not observed elsewhere thanks to the extraordinary controllability and tunability of phononic metamaterials as well as versatile measuring techniques. These phenomena include, but not limited to, topological negative refraction, topological 'sasers' (i.e. the phononic analog of lasers), higher-order topological insulating states, non-Abelian topological phases, higher-order Weyl semimetal phases, Majorana-like modes in Dirac vortex structures and fragile topological phases with spectral flows. Here we review the developments in the field of topological phononic metamaterials from both theoretical and experimental perspectives with emphasis on the underlying physics principles. To give a broad view of topological phononics, we also discuss the synergy with non-Hermitian effects and cover topics including synthetic dimensions, artificial gauge fields, Floquet topological acoustics, bulk topological transport, topological pumping, and topological active matters as well as potential applications, materials fabrications and measurements of topological phononic metamaterials. Finally, we discuss the challenges, opportunities and future developments in this intriguing field and its potential impact on physics and materials science.

7.
Nat Mater ; 21(4): 430-437, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35314775

RESUMO

Gauge fields play a major role in understanding quantum effects. For example, gauge flux insertion into single unit cells is crucial towards detecting quantum phases and controlling quantum dynamics and classical waves. However, the potential of gauge fields in topological materials studies has not been fully exploited. Here, we experimentally demonstrate artificial gauge flux insertion into a single plaquette of a sonic crystal with a gauge phase ranging from 0 to 2π. We insert the gauge flux through a three-step process of dimensional extension, engineering a screw dislocation and dimensional reduction. Additionally, the single-plaquette gauge flux leads to cyclic spectral flows across multiple bandgaps that manifest as topological boundary states on the plaquette and emerge only when the flux-carrying plaquette encloses the Wannier centres. We termed this phenomenon as the topological Wannier cycle. This work paves the way towards sub-unit-cell gauge flux, enabling future studies on synthetic gauge fields and topological materials.

8.
Opt Express ; 31(11): 18487-18496, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-37381558

RESUMO

Non-Hermitian photonic systems with balanced gain and loss have become significantly more popular due to their potential applications in communications and lasing. In this study, we introduce the concept of optical parity-time (PT) symmetry to zero-index metamaterials (ZIMs) to investigate the transport of electromagnetic (EM) waves through a PT-ZIM junction in a waveguide system. The PT-ZIM junction is formed by doping two dielectric defects of the same geometry in the ZIM, with one being the gain and the other being the loss. It is found that the balanced gain and loss can induce a perfect transmission resonance in a perfect reflection background, and the resonant linewidth is controllable and determined by the gain/loss. The smaller the gain/loss, the narrower the linewidth and the larger the quality (Q) factor of the resonance. This finding originates from the fact that the introduced PT symmetry breaks the spatial symmetry of the structure, leading to the excitation of quasi-bound states in the continuum (quasi-BIC). Additionally, we also show that the lateral displacements of the two cylinders play a crucial role in the electromagnetic transport properties in ZIMs with PT symmetry, which breaks the common sense that the transport effect in ZIMs is location-independent. Our results provide a new approach to manipulate the interaction of EM waves with defects in ZIMs using gain and loss to achieve anomalous transmission, and a pathway to investigate non-Hermitian photonics in ZIMs with potential applications in sensing, lasing, and nonlinear optics.

9.
Entropy (Basel) ; 25(3)2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36981386

RESUMO

Thermoelectric rectification and amplification were investigated in an interacting quantum-dot circuit-quantum-electrodynamics system. By applying the Keldysh nonequilibrium Green's function approach, we studied the elastic (energy-conserving) and inelastic (energy-nonconserving) transport through a cavity-coupled quantum dot under the voltage biases in a wide spectrum of electron-electron and electron-photon interactions. While significant charge and Peltier rectification effects were found for strong light-matter interactions, the dependence on electron-electron interaction could be nonmonotonic and dramatic. Electron-electron interaction-enhanced transport was found under certain resonance conditions. These nontrivial interaction effects were found in both linear and nonlinear transport regimes, which manifested in charge and thermal currents, rectification effects, and the linear thermal transistor effect.

10.
J Neurochem ; 162(3): 290-304, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35598091

RESUMO

Alzheimer's disease (AD) remains a leading cause of dementia and no therapy that reverses underlying neurodegeneration is available. Recent studies suggest the protective role of artemisinin, an antimalarial drug, in neurological disorders. In this study, we investigated the therapeutic potential of artesunate, a water-soluble derivative of artemisinin, on amyloid-beta (Aß)-treated challenged microglial BV-2, neuronal N2a cells, and the amyloid precursor protein/presenilin (APP/PS1) mice model. We found that Aß significantly induced multiple AD-related phenotypes, including increased expression/production of pro-inflammatory cytokines from microglial cells, enhanced cellular and mitochondrial production of reactive oxygen species, promoted mitochondrial fission, inhibited mitochondrial fusion, suppressed mitophagy or biogenesis in both cell types, stimulated apoptosis of neuronal cells, and microglia-induced killing of neurons. All these in vitro phenotypes were attenuated by artesunate. In addition, the over-expression of the mitochondrial fission protein Drp-1, or down-regulation of the mitochondrial fusion protein OPA-1 both reduced the therapeutic benefits of artesunate. Artesunate also alleviated AD phenotypes in APP/PS1 mice, reducing Aß deposition, and reversing deficits in memory and learning. Artesunate protects neuronal and microglial cells from AD pathology, both in vitro and in vivo. Maintaining mitochondrial dynamics and simultaneously targeting multiple AD pathogenic mechanisms are associated with the protective effects of artesunate. Consequently, artesunate may become a promising therapeutic for AD.


Assuntos
Doença de Alzheimer , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Artesunato/metabolismo , Artesunato/farmacologia , Artesunato/uso terapêutico , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Dinâmica Mitocondrial , Proteínas Mitocondriais/metabolismo , Neurônios/metabolismo , Presenilina-1/genética
11.
Nat Mater ; 20(6): 794-799, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33859382

RESUMO

Weyl semimetals (WSMs)1 exhibit phenomena such as Fermi arc surface states, pseudo-gauge fields and quantum anomalies that arise from topological band degeneracy in crystalline solids for electrons1 and metamaterials for photons2 and phonons3. Here we report a higher-order Weyl semimetal (HOWSM) in a phononic system that exhibits topologically protected boundary states in multiple dimensions. We created the physical realization of the HOWSM in a chiral phononic crystal with uniaxial screw symmetry. Using acoustic pump-probe spectroscopies, we observed coexisting chiral Fermi arc states on two-dimensional surfaces and dispersive hinge arc states on one-dimensional hinge boundaries. These topological boundary states link the projections of the Weyl points (WPs) in different dimensions and directions, and hence demonstrate the higher-order topological physics4-8 in WSMs. Our study further establishes the fundamental connection between higher-order topology and Weyl physics in crystalline materials and should stimulate further work on other potential materials, such as higher-order topological nodal-line semimetals.

12.
Opt Express ; 30(10): 17204-17220, 2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-36221548

RESUMO

The simulation of fermionic relativistic physics, e.g., Dirac and Weyl physics, has led to the discovery of many unprecedented phenomena in photonics, of which the optical-frequency realization is, however, still challenging. Here, surprisingly, we discover that the woodpile photonic crystals commonly used for optical frequency applications host exotic fermion-like relativistic degeneracies: a Dirac nodal line and a fourfold quadratic point, as protected by the nonsymmorphic crystalline symmetry. Deforming the woodpile photonic crystal leads to the emergence of type-II Dirac points from the fourfold quadratic point. Such type-II Dirac points can be detected by its anomalous refraction property which is manifested as a giant birefringence in a slab setup. Our findings provide a promising route towards 3D optical Dirac physics in all-dielectric photonic crystals.

13.
Opt Lett ; 47(6): 1454-1457, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35290337

RESUMO

The recent advancements in higher-order topology have provided unprecedented opportunities in optical device designs and applications. Here, we propose a new, to the best of our knowledge, method to realize rainbow trapping based on higher-order topological corner modes (HOTCMs), which are constructed by two configurations of breathing kagome photonic crystals with distinct topological phases. Interestingly, the HOTCMs localized at corners with different geometric configurations are found to be frequency dispersive and thus initiate the possible application in realizing rainbow trapping. By designing a polygon structure containing several configurations of corners, we demonstrate that the HOTCMs can be excited with the frequency sequence locked to the corner order (clockwise/anticlockwise direction) in the polygon. The reported HOTCMs provide a new mechanism to realize multiple-frequency trapping, which may find potential applications in future integrated photonics.

14.
Phys Rev Lett ; 129(21): 215901, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36461959

RESUMO

High quality nanomechanical oscillators are promising platforms for quantum entanglement and quantum technology with phonons. Realizing coherent transfer of phonons between distant oscillators is a key challenge in phononic quantum information processing. Here, we report on the realization of robust unidirectional adiabatic pumping of phonons in a parametrically coupled nanomechanical system engineered as a one-dimensional phononic topological insulator. By exploiting three nearly degenerate local modes-two edge states and an interface state between them-and the dynamic modulation of their mutual couplings, we achieve nonreciprocal adiabatic transfer of phononic excitations from one edge to the other with near unit fidelity. We further demonstrate the robustness of such adiabatic transfer of phonons in the presence of various noises in the control signals. Our experiment paves the way toward nonreciprocal phonon dynamics via adiabatic pumping and is valuable for phononic quantum information processing.

15.
Phys Rev Lett ; 129(15): 154301, 2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36269958

RESUMO

Disclinations-topological defects ubiquitously existing in various materials-can reveal the intrinsic band topology of the hosting material through the bulk-disclination correspondence. In low-dimensional materials and nanostructure such as graphene and fullerenes, disclinations yield curved surfaces and emergent non-Euclidean geometries that are crucial in understanding the properties of these materials. However, the bulk-disclination correspondence has never been studied in non-Euclidean geometry, nor in systems with p-orbital physics. Here, by creating p-orbital topological acoustic metamaterials with disclination-induced conic and hyperbolic surfaces, we demonstrate the rich emergent bound states arising from the interplay among the real-space geometry, the bulk band topology, and the p-orbital physics. This phenomenon is confirmed by clear experimental evidence that is consistent with theory and simulations. Our experiment paves the way toward topological phenomena in non-Euclidean geometries and will stimulate interesting research on, e.g., topological phenomena for electrons in nanomaterials with curved surfaces.

16.
Theor Appl Genet ; 135(1): 321-336, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34657161

RESUMO

KEY MESSAGE: SYL3-k allele increases the outcrossing rate of male sterile line and the yield of hybrid F1 seeds via enhancement of endogenous GA4 content in Oryza sativa L. pistils. The change in style length might be an adaptation of rice cultivation from south to north in the northern hemisphere. The style length (SYL) in rice is one of the major factors influencing the stigma exertion, which affects the outcross rate of male sterile line and the yield of hybrid F1 seeds. However, the biological mechanisms underlying SYL elongation remain elusive. Here, we report a map-based cloning and characterisation of the allele qSYL3-k. The qSYL3-k allele encodes a MADS-box family transcription factor, and it is expressed in various rice organs. The qSYL3-k allele increases SYL via the elongation of cell length in the style, which is associated with a higher GA4 content in the pistil. The expression level of OsGA3ox2 in pistils with qSYL3-k alleles is significantly higher than that in pistils with qSYL3-n allele on the same genome background of Nipponbare. The yield of F1 seeds harvested from plants with 7001SSYL3-k alleles was 16% higher than that from plants with 7001SSYL3-n allele. The sequence data at the qSYL3 locus in 136 accessions showed that alleles containing the haplotypes qSYL3AA, qSYL3AG, and qSYL3GA increased SYL, whereas those containing the haplotype qSYL3GG decreased it. The frequency of the haplotype qSYL3GG increases gradually from the south to north in the northern hemisphere. These findings will facilitate improvement in SYL and yield of F1 seeds henceforward.


Assuntos
Flores/genética , Proteínas de Domínio MADS/genética , Oryza/genética , Proteínas de Plantas/genética , Flores/anatomia & histologia , Flores/metabolismo , Giberelinas/metabolismo , Proteínas de Domínio MADS/fisiologia , Oryza/anatomia & histologia , Oryza/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/fisiologia
17.
J Clin Lab Anal ; 36(10): e24631, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36030554

RESUMO

OBJECTIVE: The objective was to investigate the expression of the cGAS-STING pathway-associated protein in idiopathic inflammatory myopathy (IIM) and to investigate whether it is related to myofiber atrophy/necrosis in patients with dermatomyositis and immune-mediated necrotizing myopathy. MATERIAL AND METHODS: Muscle specimens obtained by open biopsy from 26 IIM patients (14 with dermatomyositis (DM), 8 with immune-mediated necrotizing myopathy (IMNM), and 4 with other types of IIM), 4 dystrophinopathy, and 9 control patients were assessed for expression of cGAS-STING pathway members via Western blot, quantitative real-time PCR analysis (qRT-PCR), and immunochemistry. Meanwhile, analysis its location distribution througn immunochemistry. RESULTS: Compared to the control group, the expression of cGAS, STING, and related molecules was obviously increased in muscle samples of IIM patients. Upregulated cGAS and STING were mainly located in the vascular structure, inflammatory infiltrates, and atrophic and necrotic fibers. While comparing to the Dys patients, the mRNA level of cGAS, STING, and TNF-a was upregulated, meanwhile, the protein of the TBK1, P-TBK1, and P-IRF3 associated with interferon upregulation was overexpressed through Western blot in IMNM and DM. Considering that cGAS and STING are located in necrotic and Mx1-positive atrophic fibers, it is really possible that the cGAS-STING pathway may lead to fibers atrophy/necrosis by producing IFNs. CONCLUSION: The cGAS-STING pathway was activated in the muscle samples of IIM patients and its activation may be the reason of myofiber atrophy and necrosis in DM and IMNM patients.


Assuntos
Doenças Autoimunes , Dermatomiosite , Miosite , Atrofia , Humanos , Interferons , Necrose , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , RNA Mensageiro
18.
Int J Sports Med ; 43(5): 444-454, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34688220

RESUMO

Many studies have confirmed that exhaustive exercise has adverse effects on the heart by generating reactive oxygen species (ROS). S100A1 calcium-binding protein A1 (S100A1) is a regulator of myocardial contractility and a protector against myocardial injury. However, few studies have investigated the role of S100A1 in the regulation of myocardial injury induced by exhaustive exercise. In the present study, we suggested that exhaustive exercise led to increased ROS, downregulation of S100a1, and myocardial injury. Downregulation of S100a1 promoted exhaustive exercise-induced myocardial injury and overexpression of S100A1 reversed oxidative stress-induced cardiomyocyte injury, indicating S100A1 is a protective factor against myocardial injury caused by exhaustive exercise. We also found that downregulation of S100A1 promoted damage to critical proteins of the mitochondria by inhibiting the expression of Ant1, Pgc1a, and Tfam under exhaustive exercise. Our study indicated S100A1 as a potential prognostic biomarker or therapeutic target to improve the myocardial damage induced by exhaustive exercise and provided new insights into the molecular mechanisms underlying the myocardial injury effect of exhaustive exercise.


Assuntos
Miocárdio , Proteínas S100 , Coração , Humanos , Miocárdio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteínas S100/química , Proteínas S100/metabolismo , Proteínas S100/uso terapêutico
19.
Opt Express ; 29(24): 40606-40616, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34809396

RESUMO

We proposed an one-dimensional layer-stacked photonic crystal using anisotropic materials to realize ideal type-II Weyl points. The topological transition from Dirac to Weyl points can be clearly observed by tuning the twist angle between layers. Also, on the interface between the photonic type-II Weyl material and air, gapless surface states have been demonstrated in an incomplete bulk bandgap. By breaking parameter symmetry, these ideal type-II Weyl points would transform into the non-ideal ones, exhibiting topological surface states with single group velocity. Our work may provide a new idea for the realization of photonic semimetal phases by utilizing naturally anisotropic materials.

20.
Phys Rev Lett ; 127(14): 144502, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34652207

RESUMO

Despite a long history of studies, acoustic waves are generally regarded as spinless scalar waves, until recent research revealed their rich structures. Here, we report the experimental observation of skyrmion configurations in acoustic waves. We find that surface acoustic waves trapped by a designed hexagonal acoustic metasurface give rise to skyrmion lattice patterns in the dynamic acoustic velocity fields (i.e., the oscillating acoustic air flows). Using an acoustic velocity sensing technique, we directly visualize a Néel-type skyrmion configuration of the acoustic velocity fields. We further demonstrate, respectively, the controllability and robustness of the acoustic skyrmion lattices by tuning the phase differences between the acoustic sources and by introducing local perturbations in our setup. Our study unveils a fundamental acoustic phenomenon that may enable unprecedented manipulation of acoustic waves and may inspire future technologies including advanced acoustic tweezers for the control of small particles.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA