Optical Model Research Articles

Real-time scan-free non-line-of-sight imaging

Real-time non-line-of-sight imaging is crucial for practical applications. Among existing methods, transient methods present the best visual reconstruction ability. However, most transient methods require a long acquisition time, thus failing to deal with real-time imaging tasks. Here, we provide a dual optical coupling model to describe the spatiotemporal propagation of photons in free space, then propose an efficient non-confocal transformation algorithm and establish a non-confocal time-to-space boundary migration model. Based on these, a scan-free boundary migration method is proposed. The data acquisition speed of the method can reach 151 fps, which is ∼7 times faster than the current fastest data acquisition method, while the overall imaging speed can also reach 19 fps. The background stability brought by fast scan-free acquisition makes the method suitable for dynamic scenes. In addition, the high robustness of the model to noise makes the method have the capability of non-line-of-sight imaging in outdoor environments during the daytime. To further enhance the practicality of this method in real-world scenarios, we exploit the statistical prior and propose a plug-in-and-play super-resolution method to extract higher spatial resolution signals, reducing the detector array requirement from 32 × 32 to 8 × 8 without compromising imaging quality, thus reducing the device expense of detectors.

Dispersive optical-model potential parameters for neutron scattering on 197Au up to 200 MeV

In this study, dispersive optical model (DOM) potential parameters were derived for the 197Au target nucleus up to an incident neutron energy of 200 MeV. The procedure involved fitting the theoretical total cross sections σtot with the experimental ones and thereby determining the valid free potential parameters at the lowest value of χ2/M. The contribution of compound nuclei mechanism at low energies was also incorporated in the calculations. The theoretical results obtained using the derived potential were compared to the experimental data for both the angular differential cross-section and the elastic cross-section. While there was a good agreement with the experimental values for the total cross section, a satisfactory agreement was achieved for the angular cross section. The obtained potential is useful for describing the n+197Au scattering system and its outputs over an extensive energy spectrum.

Theoretical studies on the scattering of e± off the C2H2 molecule

Abstract By employing previous models [15,18], we report the differential, integrated elastic, inelastic, total (elastic+inelastic), viscosity and momentum transfer cross sections of e±- C2H2 collision dynamics, for the energy range of 1 eV-1 MeV. This report also incorporates Sherman spin polarization function and total ionization cross section. This work provides the first comprehensive study of electron/positron scattering from C2H2 over such a wide energy range. A complex optical model potential (OMP) has been used to represent the projectile-atom interaction. Relativistic Dirac equation has been solved, to get phase-shifts, needed for the calculations of scattering observables, using OMP. Our results are compared with the existing experimental data and theoretical calculations.

Lithographically defined cavities with high Quality and Purcell factors

Abstract We introduce and analyze a lithographically defined cavity (Li-cavity) incorporating a buried mesa defect in a planar vertical structure, which induces transverse photonic confinement while enabling compatibility with electrical injection. We systematically investigate the influence of key cavity parameters on optical behavior and fundamental properties using a comprehensive three-dimensional optical model. Our analysis reveals that the Li-cavity exhibits low optical scattering, resulting in high Q and Purcell factors, even at sub-wavelength dimensions. Furthermore, the Li-cavity supports single-mode operation within a broader aperture size range compared to conventional cavity designs, promising enhanced optical power of single-mode emission. Adequately designed structures demonstrate superior Q and Purcell factors at wavelength scale sizes,- outperforming conventional micropillar cavities. These improved properties and customizable device characteristics stem from a simple fabrication process that precisely controls the cavity size, shape, and optical mode. Superior characteristics, along with its adaptability to diverse materials, wavelengths, and photonic integration platforms, promise a broad range of applications and potential adaptation of this design to diverse photonic devices.

Exploring supersymmetry: Interchangeability between Jaynes-Cummings and anti-Jaynes-Cummings models

The supersymmetric connection that exists between the Jaynes-Cummings (JC) and anti-Jaynes Cummings (AJC) models in quantum optics is unraveled entirely. A new method is proposed to obtain the temporal evolution of observables in the AJC model using supersymmetric techniques, providing an overview of its dynamics and extending the calculation to full photon counting statistics. The approach is general and can be applied to determine the high-order cumulants given an initial state. The analysis reveals that engineering the collapse-revival behavior and the quantum properties of the interacting field is possible by controlling the initial state of the atomic subsystem and the corresponding atomic frequency in the AJC model. The substantial potential for applications of supersymmetric techniques in the context of photonic quantum technologies is thus demonstrated. Published by the American Physical Society 2024

Source distribution correlation enabled self-attention residual network for effective reconstruction of optical molecular tomography

As a promising preclinical imaging technique, optical molecular tomography (OMT) shows great potential in early detection and diagnosis of tumor diseases. However, its widespread application has been hindered by the limitations of traditional reconstruction methods, specifically the accuracy of optical transmission models and the ill-posed nature of inverse reconstruction. The development of deep learning has offered novel solutions for OMT, enabling efficient reduction of the ill-posed nature in reconstruction. The existing deep learning approaches employ conventional neural networks and objective functions, which retains significant scope for enhancing the accuracy of image reconstruction. In this paper, we propose a source distribution correlation enabled self-attention residual network (DCeSR network) to address the need for accurate OMT reconstruction. The DCeSR network leverages a residual learning strategy and a self-attention mechanism to effectively integrate the deep and shallow features, subsequently extracting highly informative surface measurements to accurately predict the three-dimensional distribution of light sources within tissues. The efficacy of the DCeSR network was validated through training and testing with two distinct numerical simulated datasets, each encompassing both single and dual source configurations. Both qualitative and quantitative analyses demonstrate the superior performance of the DCeSR network in achieving accurate OMT reconstructions.

Flow and equation of state of nuclear matter at Ekin/A=0.25\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\varvec{E_\ extrm{kin}/A=0.25}}$$\\end{document}–1.5 GeV with the SMASH transport approach

We present a comparison of directed and elliptic flow data by the FOPI collaboration in Au–Au, Xe–CsI, and Ni–Ni collisions at beam kinetic energies from 0.25 to 1.5 GeV per nucleon to simulations using the SMASH hadronic transport model. The Equation of State is parameterized as a function of nuclear density and momentum dependent potentials are newly introduced in SMASH. With a statistical analysis, we show that within the present status of the SMASH transport model, the collective flow data at lower energies is in the best agreement with a soft momentum dependent potential, while the elliptic flow at higher energies requires a harder momentum dependent equation of state.

Time-harmonic optical flow with applications in elastography

Abstract In this paper, we propose mathematical models for reconstructing the optical flow in time-harmonic elastography. In this image acquisition technique, the object undergoes a special time-harmonic oscillation with known frequency so that only the spatially varying amplitude of the velocity field has to be determined. This allows for a simpler multi-frame optical flow analysis using Fourier analytic tools in time. We propose three variational optical flow models and show how their minimization can be tackled via Fourier transform in time. Numerical examples with synthetic as well as real-world data demonstrate the benefits of our approach.

Progress in ab initio in-medium similarity renormalization group and coupled-channel method with coupling to the continuum

AbstractOver the last decade, nuclear theory has made dramatic progress in few-body and ab initio many-body calculations. These great advances stem from chiral effective field theory ($$\chi$$ χ EFT), which provides an efficient expansion and consistent treatment of nuclear forces as inputs of modern many-body calculations, among which the in-medium similarity renormalization group (IMSRG) and its variants play a vital role. On the other hand, significant efforts have been made to provide a unified description of the structure, decay, and reactions of the nuclei as open quantum systems. While a fully comprehensive and microscopic model has yet to be realized, substantial progress over recent decades has enhanced our understanding of open quantum systems around the dripline, which are often characterized by exotic structures and decay modes. To study these interesting phenomena, Gamow coupled-channel (GCC) method, in which the open quantum nature of few-body valence nucleons coupled to a deformed core, has been developed. This review focuses on the developments of the advanced IMSRG and GCC and their applications to nuclear structure and reactions.

Multiphysics Simulation of Continuous Liquid Interface Production (CLIP) 3D Printing Technology

Abstract This study explores the advancements of 3D printing through Continuous Liquid Interface Production (CLIP), which has achieved a remarkable 100-fold increase in print speed over conventional stereolithography. CLIP’s rapid printing is enabled by an oxygen inhibition layer above the resin-vat window, initiating photopolymerization above the deadzone for faster resin flow. Despite CLIP’s notable speed advantage, it struggles with artifacts arising from non-optimal print cofigurations. Our research addresses this challenge by developing a novel multiphysics simulation tool. In order to evaluate the effects of various parameters, this study introduces a 2D-CLIP multiphysics simulation tool integrating optical and chemical models. The simulation tool employs a MATLAB-PDE solver that incorporates multiphysics equations to forecast deadzone thickness and cured dimensions at various print settings. This approach allows for a comprehensive understanding of the CLIP process and its variables. The simulation tool effectively predicts key parameters, aiding in the fine-tuning of the printing process. It significantly reduces experimental costs and time while enhancing the precision of CLIP 3D printing. The tool’s predictions are instrumental in optimizing print parameters, thereby mitigating the prevalent artifacts in printed objects. This research contributes a pioneering simulation tool for CLIP 3D printing, addressing the critical gap in optimizing print configurations. Its innovative approach in integrating multiphysics models within a simulation framework offers a valuable asset in advancing the capabilities of high-speed 3D printing technologies.

An introduction to the “balance of fear”: case studies of North Korea’s challenge to the United States and South Korea’s KMPR against North Korea

ABSTRACT In late 2023, North Korea announced its intention to attack and annex South Korea despite the US’ nuclear umbrella for South Korea. Simultaneously, South Korea has been threatening a its decapitation operation against the North Korean leader. How does a small nuclear state, North Korea, ignore the nuclear umbrella of the United States, the nuclear superpower, and a non-nuclear South Korea challenge North Korea? This article introduces the “balance of fear” concept to search for answers to these two questions. It argues that the conventional “balance of terror” concept and the “balance of resolve” concept as well cannot provide a sufficient answer. In contrast, the balance of fear concept explains that not the strength of nuclear forces, but the amount of fear decides the failure or success in deterrence: North Korean leaders may have less fear for US massive retaliation than the US leaders’ fear for North Korea’s suicidal nuclear attack on US cities.

Distinguishing between aquo and hydroxo coordination in molecular copper complexes by 1H and 17O ENDOR spectroscopy.

Aquo and hydroxo ligands play an essential role in the chemistry of many copper enzymes and small molecule catalysts. The formation of a series of copper complexes with H2O and OH- ligands in various positions, including [Cu(bpy)(OAc)(H2O)2,ax]+ (Cu-I), [Cu(bpy)(OH)2,eq(HxO)2,ax] (Cu-III), [Cu(OH)4,eq(HxO)2,ax]2- (Cu-IV), [Cu(bpy)(H2O)2,eq(H2O)2,ax]2+ (Cu-V) and [Cu(bpy)2(H2O)ax]2+ (Cu-VI), were investigated through Electron Paramagnetic Resonance (EPR) and UV-Vis spectroscopy in aqueous copper bipyridine solutions in the dependence of the pH and the copper-to-bipyridine ratio (bpy = 2,2'-bipyridine). 2H- and 17O-enrichment of the copper complexes allowed us to determine the 1H and 17O nuclear hyperfine interactions of their HxO ligands via Q-band Electron Nuclear Double Resonance (ENDOR) spectroscopy. These techniques gave direct insight into the metal-ligand covalencies and geometries and were further supported by Density Functional Theory (DFT) calculations. It is shown that 1H and 17O ENDOR spectroscopy can aid in (1) determining the coordination position, thereby differentiating between equatorial and axial HxO ligands and (2) distinguishing equatorial aqua and hydroxo ligands, particularly through their anisotropic dipolar components. We further studied the influence of trans coordinating ligands on the hyperfine parameters of aquo and hydroxo ligands, enabled through contrasting the coordination environments in the examined complexes, supported by quantum chemical computations.

On the relationship between shoot Silhouette area to Total needle Area Ratio (STAR) and contour length

The calculation of the shoot Silhouette area to Total needle Area Ratio (STAR) provides a method for assessing the light interception efficiency of a coniferous shoot. We illustrate the effectiveness of a close-range, blue light 3D scanning system as a new, affordable, and highly efficient technique for estimating STAR values. The distributions of STAR and contour length of shoots for most of the diverse species studied here are similar to those of a recently proposed optical model of a Norway spruce (Picea abies) shoot (Kuusk, A., Borysenko, O., Pisek, J., 2023. Optical model of a conifer shoot. Journal of Quantitative Spectroscopy and Radiative Transfer 310, 108,715). This implies that the conclusions, regarding the radiation scattering in a shoot can be more widely applicable and extended to the species with longer and curved, twisted needles as well.

TORquing chromatin: the regulatory role of TOR kinase on chromatin function.

The Target of Rapamycin (TOR) kinase is a critical regulator of plant growth and development, integrating environmental and internal signals to modulate cellular processes. This review explores the emerging role of TOR in chromatin regulation, with a focus on its nuclear activities and interactions with chromatin remodeling factors. We highlight the mechanisms by which TOR influences chromatin structure and gene expression, including its involvement in histone modifications and DNA methylation. Additionally, the review discusses the interplay between TOR signaling, the cytoskeleton, and nuclear functions, emphasizing the potential of TOR to act as a bridge between cytoskeletal dynamics and chromatin regulation. Finally, besides TOR-mediated cyto-nuclear shuttling and metabolic regulation, we address the translational control of chromatin components by TOR as additional layers impacting the chromatin landscape. We also propose future research directions to further elucidate the complex regulatory network governed by TOR in plant cells.

Gravitational bremsstrahlung from Yukawa and nucleon collisions

We obtain the gravitational emission from particles scattering via the Yukawa interaction, presenting both classical and approximate quantum results. We also estimate the contribution from the tensor part of the internucleon interaction. This emission is the main source of a very high frequency component to the stochastic background in the Solar System and in neutron stars. The emission from the Sun (allowing for Debye screening) and from a typical neutron star are obtained. The gravitational wave luminosity of the Sun is 41±10 MW. Published by the American Physical Society 2024

AR-DAVID: Augmented Reality Display Artifact Video Dataset

The perception of visual content in optical-see-through augmented reality (AR) devices is affected by the light coming from the environment. This additional light interacts with the content in a non-trivial manner because of the illusion of transparency, different focal depths, and motion parallax. To investigate the impact of environment light on display artifact visibility (such as blur or color fringes), we created the first subjective quality dataset targeted toward augmented reality displays. Our study consisted of 6 scenes, each affected by one of 6 distortions at two strength levels, seen against one of 3 background patterns shown at 2 luminance levels: 432 conditions in total. Our dataset shows that environment light has a much smaller masking effect than expected. Further, we show that this effect cannot be explained by compositing of the AR-content with the background using optical blending models. As a consequence, we demonstrate that existing video quality metrics perform worse than expected when predicting the perceived magnitude of degradation in AR displays, motivating further research.

AI‐Driven Learning and Regeneration of Analog Circuit Designs From Academic Papers

ABSTRACTThis paper presents an artificial intelligence (AI)‐based framework designed for learning and regenerating analog circuits from academic papers. The framework comprises four distinct modules: circuit extractor, table extractor, text extractor, and simulation executor. The circuit extractor module utilizes deep learning object detection to identify devices and their associated textual descriptions while extracting interconnections between devices. The table extractor module handles textual and image‐based tables, extracting device parameters, and simulation data. The text extractor module leverages optical character recognition (OCR) and AI models to extract supplementary information. The simulation executor employs this information to conduct simulations and optimize circuit performance. In our experiments, our method effectively extracts multimodal circuit design information, achieving an average accuracy of up to 97% in target detection within the circuit extractor module. The improved performance during the simulation process further validates the effectiveness of our framework.

Built-in physics models and proton-induced nuclear data validation using MCNP, PHITS, and FLUKA – Impact on the shielding design for proton accelerator facilities

The MCNP, PHITS, and FLUKA are general-purpose Monte Carlo (MC) radiation transport codes that are widely used for many real-world shielding problems at accelerator facilities around the world. Nuclear interactions are described in these codes by either built-in physics models, or tables with evaluated cross sections and secondary energy-angular distributions, or a combination of both. Over the decades, many code validation efforts have been made, owing to the availability of shielding benchmarks to test the physics models and nuclear data and to verify the accuracy of simulation codes.For high beam energy and high beam current accelerator applications, neutron emission through the vacuum pipe along the reverse direction of incident proton beam is an important factor for a shielding design in order to correctly assess the dose rates for workers and the structural materials of the accelerator and handle with the waste activated by the backscattered neutron fluxes. In this work, neutron-production cross sections and thick-target yield predictions from MC codes relying on physics models and nuclear data libraries are benchmarked against the experimental data, in order to assess their accuracy in predicting neutron emission and furthermore to assess the corresponding impact on shielding design.The results of this study demonstrate that the nuclear data libraries and physics models, which are not expected to give good results at lower energies (< 150 MeV) but are used anyhow when there is no nuclear data available or above the energy range where the data tables end in the so-called “mix-and-match” strategy, need further improvements. Among the investigated proton induced nuclear data libraries, JENDL-4.0/HE produces the most satisfactory agreement to experimental data for all target materials, but may still benefit from refinement. Concerning the physics models of the codes, FLUKA V4-4.0 has the best performance in terms of reproducibility of the experimental values. It is also shown that all discrepancies between the calculations and the experiments for the energy range < 10 MeV (which is dominant on the dose rates through the shield thickness), are up to factor of two. This might be considered as an acceptable figure as it is equivalent to a normal safety margin (x2) considered in shielding calculations of accelerator facilities around the world.

Enhancing Multilayer Glass Transmittance through Particle Swarm Optimization: An Experimental Approach

Abstract. This study focuses on enhancing the solar transmittance of multilayer glass in buildings located in cold northern regions to improve natural lighting efficiency and maintain indoor warmth in harsh climates. The Particle Swarm Optimization (PSO) algorithm is utilized to optimize the glass layer thickness, and an optical model is constructed to calculate the light transmittance of the multilayer glass. Through simulations and experimental analysis, the impact of different glass thickness combinations on overall transmittance is investigated. The study examines the optical properties of gradient glass and calculates changes in light transmittance under varying thickness combinations using MATLAB software. The PSO algorithm is applied for global optimization to identify the glass thickness combination that maximizes light transmittance within the specific visible light range (400nm-800nm). The experimental results, including spectral energy distribution before and after sunlight transmission, validate the accuracy of the theoretical model. The findings demonstrate that the optimized glass thickness combination significantly improves solar transmittance, especially within the visible light band, contributing to more energy-efficient and comfortable building environments in cold regions. Additionally, the potential of the PSO algorithm in global search and local convergence is analyzed, suggesting future research directions to further enhance optimization through dynamic adjustments or combining with other algorithms.

Enhancing Multilayer Glass Transmittance through Particle Swarm Optimization: An Experimental Approach

Abstract. This study focuses on enhancing the solar transmittance of multilayer glass in buildings located in cold northern regions to improve natural lighting efficiency and maintain indoor warmth in harsh climates. The Particle Swarm Optimization (PSO) algorithm is utilized to optimize the glass layer thickness, and an optical model is constructed to calculate the light transmittance of the multilayer glass. Through simulations and experimental analysis, the impact of different glass thickness combinations on overall transmittance is investigated. The study examines the optical properties of gradient glass and calculates changes in light transmittance under varying thickness combinations using MATLAB software. The PSO algorithm is applied for global optimization to identify the glass thickness combination that maximizes light transmittance within the specific visible light range (400nm-800nm). The experimental results, including spectral energy distribution before and after sunlight transmission, validate the accuracy of the theoretical model. The findings demonstrate that the optimized glass thickness combination significantly improves solar transmittance, especially within the visible light band, contributing to more energy-efficient and comfortable building environments in cold regions. Additionally, the potential of the PSO algorithm in global search and local convergence is analyzed, suggesting future research directions to further enhance optimization through dynamic adjustments or combining with other algorithms.