In this paper, we focus on studying the meron defects on checkerboard lattice based on two-band structures. Merons are two-dimensional point defects, whose topological charges give the evaluations of the Chern numbers of the two bands. We first reproduce the results of a previous model from the defect perspective. Then, the model is extended to attain the higher Chern number systems. We show that the model can achieve C=±3 structures through analyzing the charges of the merons. The energy spectrum also reveals that three gap-closed states appear on the edges.
In this study, Landau–Zener–Stückelberg–Majorana (LZSM) dynamics of tunneling transmon quantum bits (qubits) and related interference effects (interferometry) in symmetrical Josephson junctions (JJs) are theoretically investigated. Accordingly, the deviation of the driving parameters from the symmetry point and the transmon frequency are introduced, leading to fluctuations of a superconducting gap that limit the computational power of state-of-the-art transmon qubits and micro-processors. Indeed, the theoretical approach is carried withing the framework of the dynamic matrix approach (DMA) and numerical experiment measurements are reported after both single and double passages through a complexity of the transmon qubit polarization energy. Therefore, we derive generalized analytical expressions of LZSM quantum tunneling probabilities (QTP) and energy eigenvalues for multiple passages processes, which allow us to efficiently establish the transmon frequency and determine the driving parameters. Our theoretical results seem relevant for the interpretation of several LZSM interferometry mechanisms in the modulation of superconducting gap through different transmon qubit spectroscopy experiments in which tunable LZSM transitions and quantum interference patterns are demonstrated by the use of universal nonadiabatic control to implement quantum emulations. Additionally, this mapping enables the investigation of JJ effects through the identification of the corresponding modulated topological phases accumulated during the LZSM transitions, which offer new opportunities to coherently manipulate qubit states and address the energy transfer of transmon qubits on the one hand. On the other hand, it suggests possibilities to reduce sensitivity and to suspected sources of imperfection from different superconducting qubit architectures, particularly in the context of materials optimization strategies that dig out nontrivial phenomena possessing powerful quantum interferometer functionality with realistic quantum controls of tunneling transmon qubit states.
Wireless power transfer (WPT) technology has seen significant advancements, but traditional methods often struggle to meet the demands of complex application scenarios, such as simultaneously powering multiple devices wirelessly. In this paper, we explore the potential of topological corner state (TCS) for multi-load WPT, supported by both theoretical and experimental results. In two-dimensional Su–Schrieffer–Heeger (SSH) systems with only nearest-neighbor (NN) coupling, quadruple TCSs offer an efficient and robust solution for multi-load WPT. Furthermore, by developing bilayer topological structures and incorporating next-nearest-neighbor (NNN) coupling, we achieve dual TCSs and create a flexible platform for multi-load WPT. These findings highlight the diverse topological phenomena enabled by higher-order phases and present a practical approach for various wireless applications, including wireless sensing and communications.
Polaritons, formed through the strong coupling of photons with excitations such as phonons or excitons, offer powerful tools for manipulating light at subwavelength scales. Van der Waals materials, like hexagonal boron nitride (hBN) and other transition metal dichalcogenides (TMDs), present unique opportunities for controlling polaritonic modes due to their atomically thin structures and tunable optical properties. Specifically, hyperbolic polaritons in hBN enable extreme light confinement and canalization in the mid-infrared spectral range, while exciton-polaritons in TMDs exhibit strong nonlinear responses in the visible and near-infrared domains. Integrating van der Waals materials with metasurface—a tailored array of subwavelength scatterers—enables the creation of topologically protected polaritonic states, allowing unidirectional, scattering-resistant propagation. This review provides a brief review of the rapidly advancing field of topological polaritonics in van der Waals metasurfaces, covering not only topological polaritonic insulators but also hyperbolic polaritons exhibiting topological transition in their dispersion contour.
In this article we examine recent developments in the research area concerning the creation of end-to-end models for the complete optimization of measuring instruments. The models we consider rely on differentiable programming methods and on the specification of a software pipeline including all factors impacting performance — from the data-generating processes to their reconstruction and the inference on the parameters of interest — along with the careful specification of a utility function well aligned with the end goals of the experiment.Building on previous studies originated within the MODE Collaboration, we focus specifically on applications involving instruments for particle physics experimentation, as well as industrial and medical applications that share the detection of radiation as their data-generating mechanism.This report illustrates the most recent advancements in the area, and outlines, for each of the discussed applications as well as for automatic differentiation itself, ongoing and future work.
Magnetic skyrmions have attracted significant attentions for their promising applications in next-generation spintronic devices. Understanding the static and dynamic properties of skyrmions is crucial for both the fundamental interest and for the design of efficient spintronic devices. Here, we present an overview of the historical and recent developments in the studies of skyrmion morphology from our perspective. First, we review the studies of skyrmion profile and size in an isolated skyrmion structure and show how the topological properties of skyrmion structure can influence the skyrmion dynamics. Second, we review the progress on understanding the relation between skyrmion lattice, stripy states, maze-like states and their mixture observed in experiments. The temperature and field effects in skyrmion lattice formation will also be discussed. Third, we briefly review the developments of composite skyrmions such as skyrmioniums and skyrmion bags. Finally, we present conclusions and outlook on some of the opportunities in skyrmion physics.
GEANT4-DNA is an expansion of the widely utilised GEANT4 Monte Carlo toolkit. This extension focuses on modelling the physical, chemical, and biological stages of ionising radiation for radiobiological applications at cellular and DNA level interactions. To date, review papers on GEANT4-DNA focus solely on evaluating a selection of the latest developments with a greater focus on mechanistic developments rather than progress in biologically specific geometries. In this work, an overview of biological analysis and biological geometries that have been developed are discussed, highlighting the latest developments and future possible development avenues for GEANT4-DNA for this application. An overview of the biological organisation levels, namely DNA, cellular, and population levels, and how GEANT4-DNA models the physical, chemical, and biological processes are also described. This review emphasises the need for persistent development of specific biological geometry accompanied by personalised DNA damage analysis parameters dependent on the biological processes considered within a specific model. It also provides an in-depth understanding of the advances at all the biological organisation levels (DNA, cellular, and population) and the use of co-operative platforms developed to model alongside GEANT4 to provide further detailed geometries and or biological damage analysis. The developments presented have been analytically discussed along with their key findings and prospects for GEANT4-DNA. Finally, a perspective on future necessary developments is portrayed since many of the advancements in the biological analysis and biological geometries discussed have not been exploited to their full potential. The development of GEANT4-DNA, using the advances discussed in this review, provides a favourable method for the evaluation of biological damage comparable to radiobiological studies.
Optical bound-states in the continuum (BICs) have greatly enriched the field of nonlinear optics with novel ways to control and manipulate light-matter interaction at the nanoscale. This has been made possible by their unique physical properties, including effective confinement of light, non-trivial topological features, and robustness upon the propagation of the optical field both in the real and momentum space. Regarding the exploration of nonlinear optical response in various photonic nanostructures supporting BICs, particular attention has been paid to optical metasurfaces, chiefly due to their ability to control the light flow at subwavelength scale, design and fabrication flexibility, and convenient phase-matching conditions. In this review, we outline and discuss recent advances in metasurface-based frequency conversion processes utilizing the versatile physics of BICs, with a particular emphasis on the main physics background pertaining to nonlinear optical phenomena and optics of BICs, as well as state-of-the-art functionalities enabled by BIC-driven nonlinear metasurfaces. These applications include harmonic generation, harmonic chiroptical effects, generation of complex quantum states, and broadband terahertz generation. In addition, several emerging research fields and the existing challenges of photonic nanodevices relying on BICs are discussed.
This paper presents an open laser parallel synchronization network comprising double centers and two chains. The double centers consist of two coupled lasers, while n (n ∈N) single lasers are used as n nodes installed in series in one chain and n single-injected lasers are used as n nodes installed in series in another chain. An external light is injected into each node's laser in one chain and a center's laser to enable the closed optical network to be developed into an open optical network. Our study demonstrates that chaos control of each node laser of the network can be achieved via external light injection, and network parallel synchronization can be obtained in two chains. We find the controlled quasi-periodic synchronization regions. When dynamic chaos control of the network is achieved by shifting the external light injection, the network obtains quasi-periodic parallel synchronization in two chains. We provide a bifurcation diagram of the closed network, a bifurcation diagram of the open network, and a bifurcation diagram varying with the external light injection, displaying routes to chaos after passing double-periodic bifurcation through four-period or quasi-period. We find that there are clear, different routes to chaos operated in the closed network and the open network and that external light injection can guide a route away from chaos, while chaos control is achieved in the open network. The results have important reference value for the study of the control and synchronization of optical networks, laser technology, complex systems, and chaos.
The Floquet-Magnus expansion (FME) and Fer expansion (FE) schemes were introduced in solid-state nuclear magnetic resonance (NMR) in 2011 and 2006, respectively. Key features of the Floquet-Magnus expansion are its ability to account for the calculations developed in a finite-dimensional Hilbert space instead of an infinite-dimensional space within the Floquet theory as well as its use of its distinguishable function, Λn(t),n=1,2,3,…, not available in other concurrent theories such as average Hamiltonian theory, Floquet theory, and Fer expansion. The distinguishable function facilitates the evaluation of the spin behavior in between the stroboscopic observation points. This paper provides an in-depth analysis of both the FME and FE methods and integrates them with the Triple Oscillating Field Technique (TOFU) in solid-state NMR. This is a significant and novel contribution as it presents a unified framework for explaining spin dynamics. The use of both FME and FE provides new theoretical insights and extends the applicability of these methods beyond traditional approaches. The application to the TOFU technique, which circumvents the dipolar truncation problem, indicates substantial practical implications for distance measurement in solid-state NMR, a critical aspect of molecular structure determination. We take advantage of the interaction frequencies and the time modulation arising from the TOFU pulse sequence, which allows selective recoupling of specific terms in the Hamiltonian that fulfill determined specific conditions. The work presented unifies and generalizes the results of the FME and FE and delivers illustrations of novel insights that boost previous applications that are based on the classical information. We believe that the revisited approaches in this work and the derived expressions can serve as useful information and numerical tools for time evolution in spin dynamics, time-resolved spectroscopy, quantum control, and quantum dynamics81,82.
Nanoscale Metal-Oxide-Semiconductor (MOS) capacitors have emerged as versatile building blocks in photonics, enabling a wide range of applications, from optical modulators to sensors. The integration of these devices with traditional CMOS technology offers the potential for low-cost, high-performance, and energy-efficient photonic systems. This review delves into the fundamental concept, high impact applications, and future prospects of nanoscale MOS capacitors in photonics. Numerical method usage and comparative results are presented to illustrate this important technological paradigm.
The review explores topologically trivial and nontrivial properties in electromagnetic metamaterials, focusing on their design principles and applications. Electromagnetic metamaterials, known for their ability to manipulate electromagnetic waves through artificial structures, have significantly advanced due to topological concepts. Topologically trivial metamaterials rely on traditional unit structures like resonators, employing geometric patterns to achieve desired wave control, such as absorption and polarization. In contrast, topologically nontrivial metamaterials utilize periodic arrangement and unique unit cells, leading to robust edge states and waveguiding properties protected against defects. Recent developments, including Möbius strip-inspired designs, demonstrate how these topological effects enhance electromagnetic functionality. The review emphasizes that the fusion of topology with metamaterials opens avenues for advanced applications in optics, communications, and quantum computing unlock new functionalities in various technological fields.
Non-Hermitian skin effect (NHSE) describes that all eigenmodes of a non-Hermitian Hamiltonian are located at the boundary of the system. Being one of the key characteristics of non-Hermitian physics, the realization of NHSE could pave the road to future applications. In this work, in analogy to the Hatano-Nelson (HN) model, we successfully construct a feasible design of photonic NHSE by using the topological ring cavities composed of photonic crystals with distinct topological properties, where the topological interface states replace the bulk states in HN model. By introducing material loss into the linkers, we propose a feasible way to tune the non-reciprocal coupling between topological ring cavities as well as the corresponding NHSE. The localization of topological interface states can be influenced by NHSE whose localization strength can be manipulated with the difference of material losses introduced. Owing to its topology nature, we verify the robustness of the proposed structure against local defects. Our proposal can also be extended to two-dimensional (2D) NHSE and higher-ordered NHSE, where we believe it will be an ideal platform to study non-Hermitian physics and intriguing applications in topological photonics.
This paper reports on the dielectric properties of undoped and manganese doped aluminum iron oxide. The solid state reaction method was was used to synthesis the samples. The dieletic function was measured over the frequency band 1kHz–10MHz at room temperature. The real part of dielectric function shows the material in ferrimagnetic/ferromagnetic order. The negative value of imaginary part of dielectric function near Fabry–Perot resonance is found to be correlated with the magnetoelectric coupling. This magnetoelectric couping effect produces a transformation between magnetic energy and electric energy. The dispersion of imaginary part of electric modulus shows two relaxation time constant for undoped aluminum iron oxide and one relaxation time constant for manganese doped aluminum iron oxide. This effect of managanese doping and transformation of electric and magnetic energy near the Fabry–Perot resonance in aluminum iron oxide may be proclaimed as the novelty of this study.
A concise and self-contained introduction to the Bell inequality in relativistic Quantum Field Theory is presented. Taking the example of a real scalar massive field, the violation of the Bell inequality in the vacuum state and for causal complementary wedges is illustrated.
Conventional Chern insulators are two-dimensional periodic structures that support unidirectional edge states at the boundary, while the wave propagation in the bulk regions is forbidden. The number of unidirectional edge states is governed by the gap Chern number, a topological invariant that depends on the global properties of the system over the entire wavevector space. This concept can also be extended to systems with a continuous translational symmetry provided they satisfy a regularization condition for large wavenumbers. Here, we discuss how the spatial dispersion, notably the high-spatial frequency behavior of the material response, critically influences the topological properties, and consequently, the net number of unidirectional edge states. In particular, we show that seemingly small perturbations of a local magnetized plasma can lead to distinct Chern phases and, consequently, markedly different edge state dispersions.
We survey the use of Chebyshev polynomials and Toeplitz theory for the study of topological metamaterials. We consider both Hermitian and non-Hermitian systems of subwavelength resonators and provide a mathematical framework to quantitatively explain and characterise some spectacular properties of metamaterials. Our characterisations are based on translation invariance properties of the capacitance matrices associated to the different investigated systems of resonators together with properties of Chebyshev polynomials. The three-term recurrence relation satisfied by the Chebyshev polynomials is shown to be the key to the mathematical analysis of spectra of tridiagonal (perturbed) both Toeplitz (for monomer systems) and 2-Toeplitz (for dimer systems) capacitance matrices.
The period-doubling oscillation emerges due to the coexistence of zero and π modes in Floquet topological insulators (FTIs). Here, leveraging the flexibility of the electric circuit, we construct a circuit with frequency-synthetic dimension to realize the FTIs of a periodically-driven model and demonstrate the topological edge states of zero and π modes. In contrast to the period-doubling oscillations observed in FTIs, the circuit exhibits deeply-subharmonic oscillations with periods extensively exceeding the doubling-driven period. Furthermore, we explore the band of the circuit with the equivalent-enhanced periodically-driven strength. Our method provides a flexible scheme to study Floquet topological phases, and open a new path for realizing the deeply subwavelength system.
We present the first published framework of the entirety of cosmological history which is thoroughly classical (without any quantum-gravitational era or singularities) and which passes all the known extensive consistency checks on such a model, and discuss some of its possible cosmological implications, such as its ability to account for the matter-antimatter asymmetry, dark flow, and the Hubble tension, albeit at the cost of further assumptions.
