Plane Wave Research Articles

Investigating soliton phenomena in incompressible fluids: Study of the (2+1)-dimensional Boiti–Leon–Manna–Pempinelli equation

The [Formula: see text]-dimensional Boiti–Leon–Manna–Pempinelli (BLMP) equation holds noteworthy practical significance and extensively applies in various scientific fields. Mathematical descriptions of nonlinear phenomena and ever-changing dynamics can be realized through mathematical modeling, which incorporates different differential equations. Because of these points, this study has examined the soliton propagation of the BLMP equation. The new soliton solutions are extracted, such as solitary, dark, bright, singular, periodic, and plane wave solutions, that have not been found in the literature before with the application of the extended simple equation method (ESEM) and modified F-expansion method (MFEM). These methods are simple and easy to calculate the solutions. Physical compatibility findings are reinforced by contour, 3D, and 2D diagrams made with different parameters. The uniqueness and differentiation of our solutions lie in the specific constraint conditions and parameter ranges considered in our study. The investigation shows that the approach used to acquire complete and distinctive solutions rapidly is successful. Based on the proposed schemes offered herein, these results can be measured as directions for potential future research through systematized and appropriate engineering and applied science methods.

Unveiling the multifunctional potential of K2YCuX6 (X=Cl,Br): Structural, mechanical and optical insights for renewable energy frontiers

This study investigates the structural, electronic, optical and mechanical properties of K2YCuX6 ([Formula: see text]) using advanced density functional theory (DFT) within the full potential linearized augmented plane wave (FP-LAPW) framework. Structural stability was validated through tolerance factor calculations, yielding values of 0.96 and 0.97 for K2YCuCl6 and K2YCuBr6, respectively, while formation energy analysis confirmed thermodynamic stability with values of [Formula: see text]1.71 and [Formula: see text]1.73[Formula: see text]eV/atom. Mechanical stability was ensured by satisfying the Born criteria. Elastic anisotropy was revealed from anisotropic factor which is found to be 1.71 and 1.73 for K2YCuX6 ([Formula: see text]). Electronic structure analysis revealed direct band gaps of 2.18[Formula: see text]eV for K2YCuCl6 and 1.84[Formula: see text]eV for K2YCuBr6, attributed to significant p,d-hybridization between Cu-3d and halogen-p orbitals. Optical properties exhibited strong absorption across the visible and ultraviolet regions, with absorption coefficients exceeding 105[Formula: see text]cm[Formula: see text]. Collectively, the findings demonstrate the multifunctional nature of K2YCuX6 ([Formula: see text]), establishing them as strong candidates for next-generation solar cells and optoelectronic devices.

High-Resolution Imaging of Targets Using Broadband Acoustic Orbital Angular Momentum Waves and Modal-Domain Focusing Beamforming

Applying the acoustic orbital angular momentum (AOAM) wave for underwater imaging can yield richer differential target echo information, a consequence of its spiral wavefront phase and multiple mutually orthogonal modes. In broadband AOAM wave imaging, the resolution of conventional beamforming is very low. Although sub-band processing can improve resolution, it cannot handle coherent signal sources. To further enhance the resolution of broadband AOAM wave underwater imaging and address the imaging issue of coherent signals in practice, this paper proposed a modal-domain focusing beamforming method. This paper initially established the echo signal model of broadband AOAM waves based on a uniform circular array. This was followed by the derivation of the beam output signal model. Finally, a new modal-domain focusing transformation matrix was constructed. Numerical results show that the proposed method reduces the background level of the beam pattern to −86dB in simple coherent target source imaging, compared with −40dB for sub-band methods and −70dB for plane wave focusing processing. Furthermore, under different noise conditions, the proposed method achieves high-resolution imaging of complex structures and good imaging of details.

Instability in nonlinear Schrödinger breathers

We consider the focusing Nonlinear Schrödinger equation posed on the one dimensional line, with nonzero background condition at spatial infinity, given by a homogeneous plane wave. For this problem of physical interest, we study the initial value problem for perturbations of the background wave in Sobolev spaces. It is well-known that the associated linear dynamics for this problem describes a phenomenon known in the literature as modulational instability, also recently related to the emergence of rogue waves in ocean dynamics. In qualitative terms, small perturbations of the background state increase its size exponentially in time. In this paper we show that, even if there is no time decay for the linear dynamics due to the modulationally unstable regime, the equation is still locally well-posed in Hs, s > 1/2. We apply this result to give a rigorous proof of the unstable character of two well-known NLS solutions: the Peregrine and Kuznetsov-Mabreathers.

Passive non-reciprocal metasurfaces based on independently tunable nonlinear dual bound states in the continuum.

Non-reciprocal devices are pivotal technologies in modern photonics, and their significance is increasingly recognized. However, achieving compact and efficient non-reciprocal devices remains a significant challenge. By leveraging optical nonlinear effects and introducing high-Q optical resonances, changes in the optical properties of the medium can be achieved, enabling non-reciprocity and reducing the required optical intensity. However, current research is limited to narrow single-wavelength ranges, hindering multi-wavelength communication applications. In this work, we propose a metasurface with the double asymmetric periodic gratings structure. This design, based on its symmetric-protected dual bound states in the continuum (BIC), enables non-reciprocal transmission and optical bistability near two wavelengths. We introduce both in-plane and out-of-plane asymmetries: in-plane asymmetry adjusts the radiation linewidth of quasi-BICs, while out-of-plane asymmetry creates asymmetric coupling of incident plane waves with the metasurface in both forward and backward directions. Furthermore, we discuss the limitations and permissible boundaries between the maximum transmission of the metasurface and the non-reciprocal intensity range (NRIR) and describe how to approach and achieve these limits. Our research broadens the application scope of non-reciprocal devices and presents a new, to the best of our knowledge, design methodology. This approach shows exciting prospects for applications such as protection in high-power lasers and non-reciprocal signal routing in simulation computations.

Symmetry-reduced loop quantum gravity: plane waves, flat space and the Hamiltonian constraint

Abstract Loop quantum gravity methods are applied to a symmetry-reduced model with homogeneity in two dimensions, derived from a Gowdy model. The conditions for the propagation of unidirectional plane gravitational waves at exactly the speed of light are set up in the form of two null Killing equations in terms of Ashtekar variables and imposed as operators on the quantum states of the system. Owing to the effective one-dimensionality, holonomies appear as simple phase factors. In correspondence, state functions might be considered as U(1) elements on a one-dimensional sequence of vertices and edges.

The formulation of the Killing conditions, containing derivatives, as discrete operators is ambiguous. Two versions are considered, one where the operators commute at every vertex, but not on neighboring vertices, and a second one with non-commutative operators at one and the same vertex. So both Killing conditions cannot be simultaneously satisfied in quantum theory.

Further, under the assumption of equal spacing of the holonomy eigenvalues, the solutions are not normalizable in the sense of the usual inner product on U(1). Taking over the inner product from the genuine gauge group SU(2) of LQG renders the obtained states normalizable, nevertheless fluctuations of geometrical quantities remain divergent. In consequence, the solutions of one or the other Killing condition have to be renormalized. Two kinds of renormalizations are presented. The combination of non-commuting Killing operators at each vertex and one of the renormalization methods turns out to make physical sense. Approximate solutions show fluctuations of the propagation speed, i. e. dispersion of gravitational waves.

Finally the same methods are applied to the Hmiltonian constraint with the same result concerning normalizability. After renormalization also the constraint is not exactly satisfied any more, which indicates the necessary presence of some kind of interacting matter.

NMR Crystallography Structure Determinations with 1H Chemical Shifts. GIPAW DFT Calculation Quality Can Be Substantially Degraded, but Nearly Identical Outputs Relative to Benchmark Computations Are Obtained: Why and So What?

Nuclear magnetic resonance (NMR) crystallography may be used in various solid-state structural characterization tasks. For organic compounds in this context, proton isotropic chemical shifts [δiso(1H)] are routinely used. It is typical to pair experimentally measured proton δiso values with δiso values that were computationally generated from crystal structure models. This can yield a δiso(1H) root-mean-squared deviation (RMSD) value for each crystal structure model. In this study, we monitor the way in which gauge including projector augmented wave (GIPAW) density functional theory (DFT) computations of 1H δiso values can be influenced by the quality of the computational input parameters. We consider 126 computationally generated (using crystal structure prediction, CSP) crystal structures for three molecules: cocaine (30 structures), flutamide (21 structures), and ampicillin (75 structures). The quality parameters selected are the plane wave energy cutoff (Ecut), and the k-point grid used to sample reciprocal (i.e., momentum) space. We also probe the utility of performing one-parameter and two-parameter linear mappings for transforming computed hydrogen isotropic magnetic shielding values (σiso) into computed δiso(1H) values. We find that both Ecut and the k-point grid can be degraded substantially (e.g., Ecut ∼ 25 Ry) and yet still produce very similar computed δiso(1H) values. We consider the mechanisms under GIPAW DFT that contribute to computed hydrogen σiso values to help understand this robustness: many contributions are zero or cancel out when converting σiso values to δiso(1H) values via the linear mapping. The robust nature of computed δiso(1H) values leads to consistent estimates of δiso(1H) RMSD values. It is then demonstrated using cocaine and flutamide that when δiso(1H) RMSD values are used in NMR crystallography tasks such as structure selection/determination, the quality of the GIPAW DFT computation can be severely degraded and still produce identical outcomes to those that used a more computationally intensive protocol. Ampicillin is selected as a practical example to probe how our findings might reasonably be applied in the structure determination of a complex organic molecule. We propose that relatively modest quality GIPAW DFT computations (i.e., Ecut = 35 Ry and a 1 × 1 × 1 k-point grid) may be used to first filter out obviously poor structure candidates. Subsequently, slightly higher quality GIPAW DFT computations can be used for structure selection/determination. Our findings indicate that it should be possible to, on average, reduce the computational resources required in such NMR crystallography tasks by approximately a factor of 3-4 in terms of CPU time.

Studying timelike proton form factors using vortex state pp¯ annihilation

Vortex states of particles—nonplane-wave solutions of the corresponding wave equation with a helicoidal wave front—open new opportunities for particle physics, unavailable in plane wave scattering. Here we demonstrate that pp¯ annihilation with a vortex proton and antiproton provides access to the phase of proton electromagnetic form factors even in unpolarized scattering. Published by the American Physical Society 2025

Plane and cylindrical waves scattering from a strip loaded single and double near zero metamaterial cylindrical object

Plane and cylindrical waves scattering from a strip loaded single and double near zero metamaterial cylindrical object

Electromagnetic optics theory of light at the isotropic interface: illustrating the behavior of the electric field

The electromagnetic behavior of light at the interface between isotropic materials is governed by the Fresnel formulas. These formulas primarily describe the electric field and are straightforward to interpret when dealing with transparent materials and incidence angles below the critical angle. However, when the incidence angle exceeds the critical angle or when the transmitted wave propagates through an absorbing medium, the mathematical description becomes more complex, and the physical behavior appears less intuitive. The aim of this work is to clarify these challenging scenarios at the undergraduate and graduate level by providing a practical mathematical formulation complemented by insightful graphical illustrations. We believe this work may also be a valuable resource for researchers and professionals. Therefore, for completeness, the mathematical treatment of inhomogeneous plane waves—often required for the second medium—is presented in the Appendix.

Quasi-coherent perfect absorption of counter-propagating vector beams of finite spatial extent through an absorptive slab.

Coherent perfect absorption (CPA) has been a topic of considerable contemporary research interest. Most of the theoretical treatment of CPA with beams relies on scalar (in some cases coupled mode) theories with inadequate input about the polarization states of the incoming light. In view of the lack of a full vectorial theory even for the original CPA configuration by Wan et al. [Science331, 889 (2011)10.1126/science.1200735], we revisit the same when the incident plane waves are replaced by well-defined vector beams with or without OAM. We study the absorption characteristics of two counter-propagating monochromatic structured beams, e.g., Gaussian and Laguerre-Gaussian (LG) beams with and without orbital angular momentum, respectively, incident normally on a composite slab from both sides by fulfilling the CPA condition exclusively for the central plane wave component. We show that though perfect absorption is not achievable, there can be a substantial reduction of the scattered light. We also consider the limitations of CPA for oblique incidence and discuss the difficulties. We believe that our study will motivate and necessitate the study of recent advancements with input vector beams, retaining the full polarization information of the off-axis spatial harmonics.

High-frequency scattering analysis of complex targets with biaxially electric anisotropic medium under arbitrary near-field excitation

This paper proposes a unified spectral-domain framework for high-frequency scattering analysis of complex targets coated with biaxially electric anisotropic medium (BEAM) under arbitrary near-field excitation. First, arbitrary electromagnetic sources are rigorously decomposed into spectral-domain plane-wave superpositions via Fourier analysis, enabling seamless integration with layered anisotropic boundary conditions. For BEAM-coated complex targets discretized into surface facets, the propagation matrices are explicitly derived for infinite planar interfaces under plane wave spectrum incidence, enabling single-facet modeling of electromagnetic interactions. Finally, based on the physical optics (PO) method, a Green's function modification tailored for scattering fields on illuminated facets is introduced, and saddle-point spectral-spatial asymptotic evaluation is employed to enable scattering field calculations for near-field excitation and reception scenarios. Compared with Titchener’s method, the proposed method is validated, and the simulation results of representative shapes coated with the BEAM layer demonstrate the correctness and effectiveness of the algorithm.

Design of Ultra Compact Optical T Flip Flop in Two Dimensional Photonic Crystals

The research in the field of quantum electronics is gaining more momentum over the solid state physics device design. In the proposed research we have designed an ultra compact optical T flip-flop in two dimensional (2-D) photonic crystals (PhCs) on a rectangular lattice with 16 × 9 dielectric rods in air configuration. The principle mechanism used here is adding an extra input called reference input to achieve logic high for no power applied at the input of T flip-flop. The two junctions are created for guiding the light wave towards the output. The reference input and one refractive index varied dielectric rod placed near the junction to confine the ouput power along with T input. At the junction of the input-output we have used the constructive and destructive interference method to achieve maximum light confinement in the output. The plane wave expansion (PWE) method is used to compute the photonic band gap (PBG) and the finite difference time domain (FDTD) method is used to analyze electromagnetic (EM) wave propagation inside the waveguides. The time for input arrival at the output also significantly improved with reduction in the chip size. The response time for the proposed T flip-flop is 0.0049 ps and contrast ratio achieved is 13.60 dB with a chip area of 49.5 μm2.

Tailored metal-insulator-metal multilayer design for perfect ir absorption at desired wavelengths in stealth systems

The plasmonic-based metamaterial has been designed with a metal-insulator-metal (MIM) structure for applying IR stealth technology. The design of two MIM unit cell structures was composed of five stacked layers. The numerical simulation showed that the designed MIM structure exhibited dual absorption peaks at resonant wavelengths of 1.3 µm and 6.7 µm and the absorptivity of both peaks reached to 98% and 96%. The first absorption peak has decreased the scattering of IR laser beams, frequently employed for detection by laser-guided devices, while the second peak represented to reduction of heat waves from the surface. Due to multiple excitations of surface plasmon at the silver-dielectric interface inside the MIM structure, the absorptivity was higher than 80% in the band 1–2 μm. Using the Finite-Difference-Time-Domain (FDTD) in computer simulation technology (CST) microwave studio, the optical resonant behavior of the designed plasmonic-based MIM structure was predicted by activating it with a plane wave using a frequency domain solver. The simultaneous excitation of electric and magnetic fields at the silver-dielectric interface has led to a high value of absorptivity with minimal backward scattering at resonant wavelength.

Impact of Soil–Structure Interaction Modeling Simplifications and Structural Nonlinearity on Uncertainty in EDPs: A Case Study on an Existing RC Building in Santiago

ABSTRACTThis study investigates the impact of modeling simplifications on the uncertainty of seismic response in numerical simulations, focusing on a five‐story, asymmetric‐plan, reinforced‐concrete building in Santiago, Chile, subjected to simulated seismic motions from hypothetical events at the San Ramón fault (SRF). In order to achieve this, a comparative analysis is conducted between a high‐complexity reference model and lower‐complexity models. The reference model incorporates three‐dimensional seismic inputs using the domain reduction method (DRM) and a detailed structural model accounting for material nonlinear behavior. The complexity of the models is systematically reduced to assess the effects of different soil–structure interaction (SSI) modeling assumptions. These assumptions include the use of DRM and plane‐wave (PW) input, and also the exclusion of SSI through fixed‐base (FB) conditions. For each model, both linear and nonlinear material behaviors are considered. Given the lack of historical records from the SRF, the study employs source‐to‐structure physical simulation to address seismic performance evaluation as well as its sensitivity to modeling. Simulations are conducted in OpenSees using input motions from 10 realizations of a event at the SRF, generated with the ShakerMaker Python library. With respect to the reference model, findings indicate that PW assumptions moderately increase uncertainty across different engineering demand parameters (EDPs) and analysis directions. Conversely, FB conditions significantly elevate modeling uncertainty, drastically changing the mean and variance of computed EDPs. A simple EDP sensitivity score is proposed to compare the statistics of computed EDPs, from which a global performance‐score is constructed for ranking of models with respect to the reference model. The ranking shows that linear FB models may outperform non‐linear FB models, highlighting a complex and nonintuitive relationship between structural nonlinearity and soil flexibility modeling on uncertainty. There are also indications that high‐complexity modeling, accounting for the spatio‐temporal complexities of the seismic wave‐field through the DRM, is needed for responses quantities sensitive to high frequencies. Overall, it is shown that even for this realistic building, located on a very stiff soil, the effects of SSI cannot be neglected as this can produce unpredictable changes in mean and variance of computed EDPs.

Analysis of multifactor damage mechanism on bridge under near-fault seismic excitation

An MS 7.4 earthquake struck China Maduo County in 2021, and it was a typical strike-slip rupture earthquake with clear directionality. A near-fault bridge named as the Yematan No.2 Bridge suffered severe seismic damage in the Maduo earthquake. To analyze the seismic damage mechanism of the Yematan No.2 Bridge, the detailed finite element model of the bridge upline and downline was established in this study. To analyze the coupled effects of soil liquefaction, traveling wave effects, and seismic inertial forces, and to make the numerical simulation results better reflect structural seismic responses under real-site liquefaction conditions, this paper proposes a simplified method for simulating ground motions in liquefiable sites. This method integrates key effects induced byliquefaction into the ground motion simulation process. The detailed finite element model of the bridge upline and downline was established in this study. Then, the near-fault seismic bedrock motion of three directional components was synthesized by using the velocity pulse method to simulate the low-frequency pulse component and the stochastic finite-fault method to simulate the high-frequency component. The seismic ground motion was inversely computed by the equivalent linear method, and the field residual displacement measurement was used to optimize the seismic ground motion amplitude. Furthermore, to study the soil liquefaction effect on the bridge seismic damage, a simplified model based on planar one-dimensional wave theory was employed, and the seismic ground motion on the soil liquefaction site was computed through the site transfer function by using the inverse Fourier transform. Finally, the bridge seismic response analysis was conducted under non-uniform seismic excitation to consider the seismic traveling wave effect. The results show that the bridge severe seismic damage is caused by the following multiple factors: (i) the fault rupture directionality of the near-fault earthquake results in the significant girder displacement along the bridge; (ii) the differential displacements between the upline and downline are also attributed to the soil liquefaction effect; (iii) the seismic traveling wave effect of strong seismic motion exacerbates the bridge seismic damage.

Using a deep neural network for the design of an optical photonic crystal half-subtractor

In this paper, a new structure, to our knowledge, for an optical half-subtractor using periodic photonic crystal structures is presented. The difference between this structure and previous ones is that a deep neural network (DNN) is used to optimize the proposed structure. A network composed of silicon rods in air is utilized to achieve the desired structure. The waveguides of this half-subtractor are designed using linear defects and a very small number of point defects. The variable parameters in this simulation are the defect rods, which are optimized by altering them. This structure, due to its simplicity in design and small size, is suitable for use in optical integrated circuits. Another advantage of this structure is the equal power output for the high states. In this study, the plane wave expansion (PWE) method was used to calculate the band structure, and the finite difference time domain (FDTD) method was used to calculate the light emission and output of light power.

Estimation of velocity vectors and evaluation of accuracy using two types of multi-angle Doppler methods on improved stenotic vessel models

Abstract Carotid artery stenosis is a major risk factor for cerebrovascular disease, requiring accurate and early diagnosis. In this study, we propose an improved stenotic blood vessel model that accounts for in vivo vascular geometry. Using two transmit center frequencies, we evaluated accuracy in estimation of blood flow velocity vectors with a multi-angle Doppler method implemented via plane wave imaging (PWI) and multi-line transmission imaging (MLTI). Among the tested conditions, MLTI at 6.94 MHz achieved the lowest root mean square error excluding bias error (RMSEexBE). However, it exhibited the highest bias error (BE), and its lower aliasing limit led to velocity folding under severe stenosis. In contrast, while the RMSEexBE in PWI was slightly higher than that in MLTI, the BE was significantly lower.

Quantum simulations of chemistry in first quantization with any basis set

Quantum computation of the energy of molecules and materials is one of the most promising applications of fault-tolerant quantum computers. Practical applications require development of quantum algorithms with reduced resource requirements. Previous work has mainly focused on quantum algorithms where the Hamiltonian is represented in second quantization with compact basis sets while existing methods in first quantization are limited to a grid-based basis. In this work, we present a new method to solve the generic ground-state chemistry problem in first quantization using any basis set. We achieve asymptotic speedup in Toffoli count for molecular orbitals, and orders of magnitude improvement using dual plane waves as compared to the second quantization counterparts. In some instances, our approach provides similar or even lower resources compared to previous first quantization plane wave algorithms that, unlike our approach, avoids the loading of the classical data. The developed methodology can be applied to variety of applications, where the matrix elements of a first quantized Hamiltonian lack simple circuit representation.

Thermal amplification and melting of phases in spin–orbit-coupled spin-1 Bose–Einstein condensates

Abstract We implement the Hartree–Fock–Bogoliubov theory with the Popov approximation for a homogeneous Raman-induced spin–orbit-coupled spin-1 Bose–Einstein condensate and investigate the effects of finite temperature (T) on the ground-state phase diagram. We calculate the roton gap as a function of Raman coupling (Ω) or quadratic Zeeman field strength (ε) to extract the critical points separating the supersolid stripe phase from the plane wave or zero-momentum phase at finite temperatures. We present a few representative finite-temperature phase diagrams for the system in the T − Ω and T − ϵ planes. Our observations indicate that the supersolid stripe phase melts at finite temperatures. We also discuss the contrasting roles of quantum and thermal fluctuations in shifting the phase boundary separating the supersolid stripe from the plane-wave phase.