Topological Charge Distribution Research Articles

Scale setting and hadronic properties in the light quark sector with ( 2+1 )-flavor Wilson fermions at the physical point

We report scale setting and hadronic properties for our new lattice QCD gauge configuration set (HAL-conf-2023). We employ (2+1)-flavor nonperturbatively improved Wilson fermions with stout smearing and the Iwasaki gauge action on a 964 lattice, and generate configurations of 8000 trajectories at the physical point. We show the basic properties of the configurations such as the plaquette value, topological charge distribution and their autocorrelation times. The scale setting is performed by detailed analyses of the Ω baryon mass. We calculate the physical results of quark masses, decay constants of pseudoscalar mesons and single hadron spectra in light quark sector. The masses of the stable hadrons are found to agree with the experimental values within a subpercent level. Published by the American Physical Society 2024

Tailoring an arbitrary large vectorial structured light beam array utilizing the tensor theory of multiplexed polarization holograms

Vectorial structured light beams, characterized by their topological charge and non-uniform polarization distribution, are highly promising beam modes for several applications in different domains of optics and photonics. To harness its potential specifically in optical communication, data encryption, and optical trapping, it is necessary to tailor a multitude of these beams with arbitrary and large topological charge and polarization distribution. However, achieving the above-mentioned requires bulky optical setups that necessitate the superposition of two beams or involve complex material fabrication techniques that can directly generate these beams. In this paper, we report the generation of a large structured light beam array by utilizing multiplexed polarization holograms, computer-generated holography, and azo-carbazole polymer film. We have developed a theoretical framework for double-exposure polarization holography that enables the possibility of tailoring such a vectorial light beam array. Utilizing the developed theory, we showcase the experimental generation of a structured vector beam array of size 8 × 8 with arbitrary topological charges and polarization distribution in 3 mm × 3 mm area of the polymer film. Exploiting the large space bandwidth of the polymer film, we also demonstrate the generation of vector vortex beam arrays with exceptionally large topological charges (l=100). All the above has been experimentally realized by simply illuminating the hologram with a plane Gaussian beam, and no additional optics are needed. This reported method offers huge potential and opens up new possibilities for the utilization of vectorial structured light beams.

Subvolume method for SU(2) Yang-Mills theory at finite temperature: topological charge distributions

We apply the previously-developed sub-volume method to study the θ-dependence of the four-dimensional SU(2) Yang-Mills theory at finite temperature. We calculate the first two coefficients, the topological susceptibility χ and the fourth cumulant b2, in the θ-expansion of the free energy density around the critical temperature (Tc) for the confinement-deconfinement transition. Lattice calculations are performed with three different spatial sizes 243, 323, 483 to monitor finite size effects, while the temporal size is fixed to be 8. The systematic uncertainty associated with the sub-volume extrapolation is studied with special care. The sub-volume method allows us to determine the values of b2 much more accurately than the standard full-volume method, and we successfully identify the temperature dependence of b2 around Tc. Our numerical results suggest that the θ-dependence of the free energy density near θ = 0 changes from 4χ(1 − cos(θ/2)) to χ(1 − cos θ) as the temperature crosses Tc.

Study of topological quantities of lattice QCD with a modified Wasserstein generative adversarial network

We propose a modified Wasserstein generative adversarial network (M-WGAN) to study the distribution of the topological charge in lattice QCD based on Monte Carlo simulations. We construct new generator and discriminator in M-WGAN to support the generation of high-quality distribution. Our results show that the M-WGAN scheme of machine learning should be helpful for us to calculate efficiently the 1D distribution of topological charge compared with the method by the Monte Carlo simulation alone. Published by the American Physical Society 2024

Study of the topological quantities of lattice QCD using a modified DCGAN frame

A modified deep convolutional generative adversarial network (M-DCGAN) frame is proposed to study the N-dimensional (ND) topological quantities in lattice QCD based on Monte Carlo (MC) simulations. We construct a new scaling structure including fully connected layers to support the generation of high-quality high-dimensional images for the M-DCGAN. Our results suggest that the M-DCGAN scheme of machine learning will help to more efficiently calculate the 1D distribution of topological charge and the 4D topological charge density compared with MC simulation alone.

Molecular structure properties, quantum computational, electronic, charge analyses and biological (drug-likeness and docking) studies on anti-inflammatory drug molecule of Balsalazide

(E)–5-([4-(2–carboxyethylcarbamoyl) phenyl] diazenyl)-2-hydroxybenzoic acid (Balsalazide) was scrutinized theoretically using quantum computational calculation. FT-IR, UV–vis., and optimized structure data were collected utilizing the DFT approach with the B3LYP functional and 6-311++G(d,p) basis set. The wave number computations and improved molecular geometry were carried out in the gas phase. Utilizing VEDA analysis, the potential energy distribution analysis PED of the title chemical was carried out. Additionally, experiments on chemical reactivity and molecular electrostatic potential (MEP) were carried out. Researchers employed the electron localization function (ELF) to demonstrate electron delocalization in the molecule. Topological and Mulliken charge distribution investigations were other subjects. Intermolecular charge transfer was interpreted using natural bond orbital analysis (NBO). RDG analysis used electron concentration as a basis. To clarify how the electronics-based transmissions in the UV–vis spectral range of several solvents (Gas, Water, DMSO, Ethanol, and Acetone) were determined, DFT analysis was also employed. Maximum wavelength (λ) absorbance and band-gap energy estimates for Balsalazide were calculated for different solvents. The electrophilicity index is used to theoretically explain bioactivity, while molecular docking is used to show how a ligand interacts with a protein. Through molecular docking, the Transcription classified proteins of 2Q1V and 4ME0 are examined. The drug-likeness of the molecule revealed its nature.

Method for generating spatiotemporal coherency vortices and spatiotemporal dislocation curves.

A simple method for designing spatiotemporal coherency vortices (STCVs) and spatiotemporal dislocation curves (STDCs) is introduced by means of coherent-mode representation and Fourier transforms. A partially coherent pulsed beam is represented by an incoherent superposition of a Gaussian and a Hermite-Gaussian pulsed beam with different waist positions. It well demonstrates that there exist STCVs and STDCs in the space-time plane. The detailed numerical calculations are performed to address the dependence of waist distance of two modes, reference position, beam order, distribution of original spectrum, topological charge and mode weights ratio on the STCVs and STDCs. The physical interpretation behind numerical results is shown. A possible scheme for experimental synthesis of the STCVs is proposed. The obtained results may have potential applications in the fields of light-matter interaction, spatiotemporal spin-orbit angular momentum coupling and STCV-based optical trapping and optical manipulation.

Synthesis of Biologically Active α-Tetralone Condensate: Growth of Single Crystal, Characterization by Experimental and Simulation Methods

The exocyclic double bonded α-tetralone condensate viz. (2E)-2-(4-propoxybenzylidene)-3,4-dihydro-1(2H)-naphthalene-1-one was synthesized by the Claisen–Schmidt reaction between α-Tetralone and 4-propoxybenzaldehyde in an alkaline medium. A slow evaporation technique was used to collect the single crystals. Researchers examined the detailed information provided by spectral studies. The inter- and intra-molecular interactions of the compound were identified using the single-crystal XRD investigation. Charge transfer inside organic molecules was used to calculate HOMO and LUMO energy values. In addition, MEP, NBO, NLO, topological charge distribution, and Mulliken population studies were performed for this compound. The Hirschfeld surface study showed that nonpolar or weakly polar interactions significantly contributed to the packing forces for molecules. Then, it was tested for its antioxidant, antidiabetic, and anti-inflammatory properties. The 6yb7 protein and the (2E)-2-(4-propoxybenzylidene)-3,4-dihydro-2H-naphthalen-1-one (PBDN) ligand were docked in molecular docking research.

Controllable plasmonic vortex sequence with on-chip discrete-slit-based metalens

Like free-space vortex beams, surface plasmon polaritons can carry orbital angular momentum to form plasmonic vortices (PVs). Recently, research interest in PV fundamentals and applications has increased. However, generating and manipulating the topological charges of PVs over wide ranges using on-chip devices remains challenging. Here, we propose an on-chip plasmonic metalens structure to generate tunable PV sequence with controllable topological charges at discrete wavelengths. When compared with conventional spiral-slit structures, the designed metalens has additional structural parameters that bring more degrees of freedom to control the range and interval of the topological charge distribution of the PV sequence. Analytical and simulation methods are used to verify the metalens’ functionality. It is proved that the topological charges of the generated PV sequence are symmetrically distributed about the fundamental mode (l = 0), which cannot be realized by a traditional Archimedean helix. In addition, the normalized powers of the PV sequence are all above 0.8, showing that the designed metalens structure has potential for use as an on-chip optical vortex comb device. This work has potential applications in on-chip optical information processing, integrated optical communications, and optical tweezers.

Synthesis, Crystal Structure, DFT Studies on Tetramethyl-(p-Tolyl)-Hexahydro-1H-Xanthene-1,8(2H)-Dione

Tetramethyl-(p-tolyl)-hexahydro-1H-xanthene-1,8(2H)-dione (P-TX) was synthesized and characterized experimentally using X-ray diffraction, FT-IR, 1H, 13 C N.M.R. and UV-Vis spectra, and theoretically using DFT calculations. The most stable optimized structure was discovered utilizing the B3LYP/6-311++G(d,p) basis set, followed by FTIR and N.M.R. investigation. The researched chemical’s ideal structure corresponds to the findings of the X-ray analysis. TD-DFT analysis also shed more light on how the electronic transitions in the UV–Vis spectra were estimated. The Hirshfeld surface analyses were presented and discussed, as well as the energy framework calculations. Other topics included topological and Mulliken charge distribution studies. The vibrational assignments were completed using individual vibrational modes, then compared to experimental data. The docking studies were utilized to investigate the interactions of the ligand (P-TX) with specific protein targets, suggesting that P-TX could be employed as a potential cytotoxic and antibacterial agent. P-TX may be considered a potential medicinal molecule due to the current research. The experimental and theoretical results were highly similar in geometric and spectroscopic characteristics.

Electrically Tunable and Robust Bound States in the Continuum Enabled by 2D Transition Metal Dichalcogenide

AbstractHigh quality factor (Q‐factor) resonance can effectively enhance light–matter interactions, but suffers from radiative losses caused by fabrication imperfections and material impurities. Merging bound states in the continuum (BICs) becomes a promising candidate to address this challenge since they generate a large high‐Q region in momentum space against undesired external perturbations. However, it is only achieved by altering the geometric parameters of the structure, which constrains its dynamical tunability once the fabrication is ready, limiting its performance in modulators and photodetectors. Here, a convenient approach is proposed to manipulating the merging BIC by electrically tuning the material properties, aiming at on‐chip photonic devices. The asymmetric merging BIC is achieved and tuned by reducing the in‐plane structural symmetry from to , which enables the inversion of topological charge and reconfigurable polarization distribution in the momentum space. Such tunable merging BIC promises various potential applications including vortex generation, optical communication, and nanolasers.

Spiral-Phase-Defect Resonator and Its Application in Vortex Laser of Controllable Topological Charges

An optical resonator with a spiral-phase defect is proposed for vortex laser generation. Theoretical models and calculations were conducted to predict the topological charge distribution of the emitted vortex laser. Utilizing a reflective spatial light modulator that creates a spiral-phase defect of variable radius and azimuthal phase modulation, vortex beams with controllable topological charges and intensity distributions were demonstrated experimentally.

Synthesis, X-Ray Diffraction, DFT and Hirshfeld Surface Studies of 9-(4-Hydroxyphenyl-Tetramethyl-Hexahydro-1H-Xanthene-1,8(2H)-Dione

9-(4-hydroxyphenyl-tetramethyl-hexahydro-1H-xanthene-1,8(2H)-dione (OH-X) was synthesized and characterized experimentally using X-ray diffraction, FT-IR, 1H, 13 C NMR, and UV-Vis spectra, and theoretically using DFT calculations. To look at stability, different physicochemical properties have been compared. The most stable optimized structure was discovered using the B3LYP/6-311++G(d,p) basis set, followed by FTIR and NMR investigation. Further details on the estimation of the electronic transitions in the UV-Vis spectra were provided by TD-DFT analysis. The Hirshfeld surface analyses were presented and discussed, as well as the energy framework calculations. The estimated maximum wavelength (λ) absorbance and the band-gap energy of OH-X were computed for various solvents and compared to the outcomes of experiments. Investigations of chemical reactivity, MEP map, and surface area maps were also carried out. To show electron delocalization in the molecule, electron localization function (ELF) and the local orbital localizer (LOL) were used. Other topics included topological and Mulliken charge distribution studies. Utilizing certain vibrational modes, the vibrational assignments were accomplished and experimental data was compared. The docking studies were utilized to investigate the interactions of the ligand (OH-X) with certain protein targets, suggesting that OH-X could be employed as a potential cytotoxic and antibacterial agent. OH-X may be considered a potential medicinal molecule as a result of the current research. In terms of geometric and spectroscopic features, the findings from the experimental and theoretical were highly comparable.

Experimental Spectroscopic, Structural (Monomer and Dimer), Molecular Docking, Molecular Dynamics Simulation and Hirshfeld Surface Analysis of 2-Amino-6-Methylpyridine

2-Amino-6-methylpyridine (2-AMP) was investigated experimentally using FT-IR, 1H, NMR, and UV-Vis spectra, as well as theoretically using DFT calculations. The quantum computational calculations (the optimized structure, FT-IR, NMR and UV-Vis.) to support experimental data were performed by DFT approach at B3LYP functional and 6–311 + +G(d,p) basis set. The optimized molecular geometry and wavenumber calculations were done in the gas phase, while theoretical NMR was performed in Chloroform (CHCL3) solvation. The “Potential Energy Distribution analysis” (PED) of the title compound was performed with VEDA analysis and these assignments were compared with the experimental FT-IR spectrum. Hirshfeld analysis was also performed and analyzed intermolecular interactions on the surface of crystal, However, the most significant contributions to the Hirshfeld surface come from N···H (17.3%), C···H/H···C (23%) and H···H (68.8%). Chemical reactivity studies, Molecular Electrostatic Potential (MEP) maps, and surface area maps were also conducted. To show electron delocalization in the molecule, researchers used the electron localization function (ELF). Other topics included topological and mulliken charge distribution studies. Natural Bond Order Analysis (NBO) was performed to interpret intermolecular charge transfer.The effect of temperature on thermodynamical parameters such as Gibbs free energy, enthalpy, and entropy was examined. TD-DFT analysis was also used to shed more light on how the electronic transitions in the UV–Vis spectra were estimated. For different solvents, the estimated maximum wavelength (λ) absorbance and the band-gap energy of 2-AMP were calculated and compared to experimental results. The molecule's bioactivity is described theoretically using the Electrophilicity index and the interaction between the ligand-protein is depicted using Molecular docking. The proteins 3DQS, 4UX6, 5ADF, 5TUD, and 6E9L were studied via molecular docking. The nature of the molecule was determined by its drug-likeness. A molecular dynamics simulation was used to explore biomolecular stability.

Topological charge distributions of an interacting two-spin system

Quantum systems are often described by parameter-dependent Hamiltonians. Points in parameter space where two levels are degenerate can carry a topological charge. Here we theoretically study an interacting two-spin system where the degeneracy points form a nodal loop or a nodal surface in the magnetic parameter space, similarly to such structures discovered in the band structure of topological semimetals. We determine the topological charge distribution along these degeneracy geometries. We show that these non-point-like degeneracy patterns can be obtained not only by fine-tuning, but they can be stabilized by spatial symmetries. Since simple spin systems such as the one studied here are ubiquitous in condensed-matter setups, we expect that our findings, and the physical consequences of these nontrivial degeneracy geometries, are testable in experiments with quantum dots, molecular magnets, and adatoms on metallic surfaces.

Hierarchy of multi-order skyrmion phases in twisted magnetic bilayers

The recent discovery of two-dimensional (2D) van der Waals magnets is a crucial turning point in the quantum magnet research field, since quantum fluctuations and experimental difficulties often elude stable magnetic orders in two dimensions. This opens new doors to delve for novel quantum and topological spin configurations, which may or may not have direct analogs in bulk counterparts. Here we study a twisted bilayer geometry of 2D magnets in which long-range spin-spin interactions naturally commence along the interlayer Heisenberg (${J}_{\ensuremath{\perp}}$) and dipole-dipole (${J}_{D}$) channels. The ${J}_{\ensuremath{\perp}}\text{\ensuremath{-}}{J}_{D}$ parameter space unveils a hierarchy of distinct skyrmion phases, including point-, rod-, and ring-shaped topological charge distributions. Furthermore, we predict a topological antiferroelectric phase, where oppositely charged antiskyrmion pairs are formed, and the corresponding topological dipole moments become ordered in a N\'eel-like state---hence dubbed the topological antiferroelectric state. The results indicate that the twisted magnetic layer provides a versatile setting to engineer and tune a plethora of skyrmion phases and their dynamics.

Light-driven Lifshitz transitions in non-Hermitian multi-Weyl semimetals

Non-Hermitian topological systems are the newest additions to the growing field of topological matter. In this work, we report the light-driven exceptional physics in a multi-Weyl semimetal. The driving is not only a key ingredient to control the position of the exceptional contours (ECs); light also has the ability to generate new ECs. Interestingly, we also demonstrate topological charge distribution and Lifshitz transition, which are controllable by the driving field in such generated ECs. Our findings present a promising platform for the manipulation and control over exceptional physics in non-Hermitian topological matter.

Fractional discrete vortex solitons.

We examine the existence and stability of nonlinear discrete vortex solitons in a square lattice when the standard discrete Laplacian is replaced by a fractional version. This creates a new, to the best of our knowledge, effective site-energy term, and a coupling among sites, whose range depends on the value of the fractional exponent $\alpha$, becoming effectively long range at small $\alpha$ values. At long distance, it can be shown that this coupling decreases faster than exponentially: $\sim\exp (- |{\textbf{n}}|)/\sqrt {|n|}$. In general, we observe that the stability domain of the discrete vortex solitons is extended to lower power levels, as the $\alpha$ coefficient diminishes, independently of their topological charge and/or pattern distribution.

Higher topological charge and the QCD vacuum

It is shown that gauge field configurations with higher topological charge modify the structure of the QCD vacuum, which is reflected in its dependence on the CP-violating topological phase $\theta$. To explore this, topological susceptibilities and the production of axion dark matter are studied here. The former characterize the topological charge distribution and are therefore sensitive probes of the topological structure of QCD. The latter depends on the effective potential of axions, which is determined by the $\theta$-dependence of QCD. The production of cold dark matter through the vacuum realignement mechanism of axions can therefore be affected by higher topological charge effects. This is discussed qualitatively in the deconfined phase at high temperatures, where a description based on a dilute gas of instantons with arbitrary topological charge is valid. As a result, topological susceptibilities exhibit a characteristic temperature dependence due to anharmonic modifications of the $\theta$-dependence. Furthermore, multi-instanton effects give rise to a topological mechanism to increase the amount of axion dark matter.

X-ray microscope for imaging topological charge and orbital angular momentum distribution formed by chirality.

The distribution of topological charges on X-ray vortices was measured by differential Fourier space filtering microscope, differential radial Hilbert transform microscope. It was experimentally verified for the first time using a Spiral Fresnel zone plate objective lens. This X-ray microscope is highly sensitive to X-ray topological defects, such as edges and vortices, at the exit-face wave field of objects. Its efficient use is also discussed.