Nuclear physics
Computational physics
Physics Education Research
Impact of Veda Chanting on Cognitive functions
Science and Spirituality
45
Scopus Publications
Scopus Publications
Genetic Algorithm Approach to Study Low-Energy Alpha–Deuteron Elastic Scattering using the Phase Function Method Arushi Sharma, Ayushi Awasthi, Jyoti Sharma, Ishwar Kant, M R Ganesh Kumar, O S K S Sastri Progress of Theoretical and Experimental Physics, 2026 The present study focuses on the analysis of elastic scattering in the $\\alpha \\!-\\!d$ system for low-energy data up to 14 $\\mathrm{MeV}$. This system holds particular significance due to its direct connection to the $^6\\mathrm{Li}$ production reaction, which is an important process in nuclear astrophysics and light nucleus synthesis. The primary objective of this investigation is to explore the low-lying excited states of positive parity with isospin $T=0$, which are crucial for accurately describing the resonance behavior and underlying nuclear dynamics of the system. The central idea of this paper is to obtain the interaction potential using the inverse scattering method: we employ the genetic algorithm approach. In this framework, the genetic algorithm is guided by the underlying physical laws, enabling accurate extraction of the inverse scattering potential from the elastic scattering data. In our methodology, as a reference potential, a combination of three smoothly joined Morse functions is utilized, characterized by 10 model parameters. These parameters are optimized in an iterative fashion to ensure the best fit to the phase shifts extracted from the experimental scattering data. The process of optimization is guided by the computed scattering phase shifts by solving the phase equation using the fifth-order Runge–Kutta method for the reference potential in each iteration. Our approach yields inverse potentials for both single- and multichannel scattering. Using the scattering phase shifts obtained from these inverse potentials, we calculate the partial cross section to determine the resonance energies and decay widths. The obtained values for the resonance energies and decay widths for the $^3D_1$, $^3D_2$, and $^3D_3$ states of $\\alpha \\!-\\!d$ are in correspondence with the experimental results.
A novel computational approach for study of proton–proton scattering Arushi Sharma, Ayushi Awasthi, O. S. K. S. Sastri Scientific Reports, 2025 In this paper, we have implemented a novel computational approach to study proton-proton scattering. The approach is applicable to all charged particle scattering scenarios and solves the challenge of incorporating the long-range Coulomb interaction alongside the short nuclear interaction using the phase function method. The key idea is to construct a reference potential using three smoothly joined Morse functions that collectively capture both nuclear and electromagnetic interactions. The reference potential is utilized in solving the phase equation which is derived by the transformation of the Schrodinger equation, for obtaining the scattering phase shifts for different values of orbital angular momentum called as $$\\ell$$ -channels (S, P, D, F, G, H). The parameters of reference potential are optimized to minimize the Mean Squared Error between obtained and expected phase shifts, resulting in the construction of inverse potential for various $$\\ell$$ -channels of the proton-proton system. Utilizing the phase shifts obtained from the inverse potentials, we have calculated the total cross-section and the low energy effective-range parameters, which have been found to be in excellent match with the experimental data.
Genetic-algorithm-based inverse potentials for resonant states of α- 12C using the variable phase approach Ayushi Awasthi, Arushi Sharma, Barbie, Ishwar Kant, O. S. K. S. Sastri Physical Review C, 2025 Elastic scattering between $\ensuremath{\alpha}$ particles and $^{12}\mathrm{C}$ nuclei plays a crucial role in understanding resonance phenomena in light nuclear systems. In this work, we construct inverse potentials for resonant states in $\ensuremath{\alpha}\text{\ensuremath{-}}^{12}\mathrm{C}$ elastic scattering using the variable phase approach, in tandem with a genetic-algorithm-based optimization technique. The reference function for the potential in the phase equation is chosen as a combination of three smoothly joined Morse-type functions. The parameters of the reference function are genetically evolved to minimize the the mean-squared error (MSE) between the numerically obtained scattering phase shifts and the expected values. To avoid overfitting and ensure model generalization, we employ a fivefold cross-validation strategy, where the genetic algorithm (GA) minimizes the average validation error across folds. The resulting inverse potentials accurately reproduce the resonance energies (${E}_{r}$) and the resonance widths (${\mathrm{\ensuremath{\Gamma}}}_{r}$) for the ${\ensuremath{\ell}}^{\ensuremath{\pi}}$ states, ${1}^{\ensuremath{-}}$, ${2}^{+}$, ${3}^{\ensuremath{-}}$, and ${4}^{+}$, showing excellent agreement with experimental data. This computational approach to constructing inverse potentials serves as a complement to conventional direct methods for investigating nuclear-scattering phenomena.
Numerical Construction of Parametrized Potentials for Nucleon-Alpha Inverse Scattering Using Variational Monte Carlo and Phase Function Method Lalit Kumar, Anil Khachi, O. S. K. S. Sastri Computational Mathematics and Mathematical Physics, 2025 Neutron and proton scattering with stable alpha particles can be represented as a two-particle system. In this work, we present a numerical algorithm developed to obtain parametric potentials of the inverse scattering problem by solving the Riccati-type non-linear differential equation, known as the phase equation, alongside the Variational Monte Carlo method. Local interaction potentials for the resonant $${{p}_{{1/2}}}$$ and $${{p}_{{3/2}}}$$ channels are constructed using the Morse potential, derived from scattering phase shift (SPS) data for neutron-alpha and proton-alpha scattering. The non-local interaction potential in the $$p\alpha $$ system is modeled using a screened Coulomb potential. The phase equation for the $${{p}_{{1/2}}}$$ and $${{p}_{{3/2}}}$$ channels is solved numerically using the fifth-order Runge–Kutta method. The parameters of the Morse function are optimized by minimizing the mean absolute percentage error (MAPE) between the calculated and experimental phase shifts, through an iterative process involving Monte Carlo sampling and variational techniques. This ensures the accurate reproduction of experimental SPS data. Resonance energies, obtained (experimental) from partial cross-section plots for the $${{p}_{{1/2}}}$$ and $${{p}_{{3/2}}}$$ states in the $$n\alpha $$ system, are 4.10 (4 ± 1) MeV and 0.93 (0.89) MeV, respectively, while for the $$p\alpha $$ system, they are 5.31 (5 ± 2) MeV and 1.97 (1.96) MeV. The total cross-section for the $$n\alpha $$ system is in agreement with values found in the literature. This study demonstrates the effectiveness of the proposed numerical algorithm for constructing parametric potentials and shows its ability to accurately reproduce phase shifts and cross-sections in line with experimental data.
Constructing inverse potentials for resonant states of α-3H and α-3He scattering directly from phase shifts Ishwar Kant, Ayushi Awasthi, Arushi Sharma, Shikha Awasthi, OSKS Sastri, MR Ganesh Kumar Physica Scripta, 2025 In this paper, the inverse potentials for the resonant f states of α-3H and α-3He are constructed using the phase function method by utilizing an reference potential approach. Central Idea: A combination of three Morse functions are chosen over three regions of interaction and are joined smoothly at the intervening boundaries to prepare the reference potential. While the regular Morse function captures the nuclear and Coulomb interactions at short and medium ranges, an inverse Morse function is chosen to obtain the Coulomb barrier that arises because of the long-range Coulomb interaction. This reference potential is representative of a large family of curves consisting of eight distinct model parameters and two intermediate points. Methodology: The phase equation is solved using the Runge-Kutta 5th order method for the input reference potential to obtain the scattering phase shifts at various center of mass energies. The model parameters are then adjusted using the genetic algorithm in an iterative fashion to minimize the mean square error between the simulated and expected phase shift values. Results: Our approach successfully constructed the inverse potentials for the resonant f states of the α-3H and α-3He systems, achieving convergence with a minimized mean square error. The resonance energies and widths for the α-3H system for the f 5 / 2 − and f 7 / 2 − states are determined to be [4.19 (4.14), 1.225 (0.918)] MeV and [2.20 (2.18), 0.099 (0.069)] MeV, respectively. For the f 5 / 2 − and f 7 / 2 − states of the α-3He system, the resonance energies and widths are [5.03 (5.14), 1.6 (1.2)] MeV and [2.99 (2.98), 0.182 (0.175)] MeV, respectively. Conclusion: Our fitting procedure of the available experimental data utilizing a combination of smoothly joined Morse functions effectively captures both short-range nuclear and long-range Coulomb interactions, providing an accurate model for nuclear scattering involving charged particles.
Variational Monte Carlo optimization of proton-proton scattering potential using the phase function method SHIKHA AWASTHI, ANIL KHACHI, O.S.K.S. SASTRI Turkish Journal of Physics, 2025 The Riccati-type nonlinear differential equation, also known as the Phase Function equation, is used to construct local inverse potentials for the 1S0 - pp state by bypassing the well-known Schrödinger equation. The pp interaction is described using the Malfliet-Tjon potential model for the nuclear component combined with a screened Coulomb potential, with the phase equation solved via the fourth-order Runge-Kutta (RK-4) method. Based on our analysis, we confirm that the optimized interaction potential closely matches the well-known realistic Argonne V18 and Reid potentials for the 1S0 state, and the computed phase shifts and cross-sections show excellent agreement with experimental data. This study demonstrates the efficacy of PFM in accurately modeling nuclear interactions, contributing to the refinement of theoretical frameworks for high-energy scattering phenomena.