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rcgiri-physics/README.md

Ram Chandra Giri

MSc Physics | Computational Physics (PhD aspirant) Nepal


About

Physics educator and computational researcher focusing on the explicit numerical modeling of non-linear dynamical systems. My work evaluates the long-term phase-space stability of Hamiltonian, Lagrangian, and dissipative chaotic models.

I treat my code repositories as formal numerical laboratories. My methodology prioritizes mathematical rigor, strict physical conservation proofs, and custom algorithmic execution over pre-built library wrappers. I am systematically building a technical and mathematical foundation for a PhD in Computational Physics and Nonlinear Dynamics.


Portfolio Projects

A computational framework designed to model, visualize, and analyze deterministic chaos within the three-dimensional, non-linear atmospheric flow model derived by Edward Lorenz.

$$ \frac{dx}{dt} = \sigma(y - x), \quad \frac{dy}{dt} = x(\rho - z) - y, \quad \frac{dz}{dt} = xy - \beta z $$

  • Numerical Engine: Implemented a standard fourth-order Runge-Kutta (RK4) integrator with adaptive time-stepping to preserve trajectory integrity across high-gradient vector fields.
  • Bifurcation Analysis: Mapped phase-space trajectories across a spectrum of Rayleigh numbers ($\rho$). Safely isolated the subcritical Hopf bifurcation ($\rho \approx 24.74$) where steady-state fixed points lose stability, giving rise to the iconic "butterfly" strange attractor.
  • Chaos Quantification: Evaluated sensitive dependence on initial conditions (SDIC) by tracking twin trajectories with an initial perturbation of $\delta \sim 10^{-8}$, calculating the maximal Lyapunov exponent ($\lambda_{max} > 0$) to verify true deterministic chaos rather than numerical noise.
  • Topology Mapping: Visualized 3D phase-space projections, plotting the dual-wing geometry to study trajectory ergodicity and fractal structure bounds.

An examination of multi-degree-of-freedom systems and the explicit onset of deterministic chaos through analytical mechanics.

  • Euler-Lagrange Derivation: Formulated the coupled, highly non-linear transcendental equations of motion using generalized coordinates ($\theta_1, \theta_2$).
  • Phase-Space Mapping: Isolated the transition boundaries where regular, low-energy invariant tori break apart into high-energy chaotic seas.
  • Poincaré Sections: Generated state-space slices to visually map the breaking of system integrability and track coordinate divergence.

A high-precision study of gravitational stability, transition to chaos, and long-term orbital conservation.

  • Symplectic Engineering: Developed a custom Velocity-Verlet (Leapfrog) engine in Python to eliminate numerical energy dissipation, maintaining a relative Hamiltonian error of $\sim 10^{-9}$.
  • Chaos Quantification: Identified a critical velocity perturbation threshold ($\delta \approx 0.5$) for stellar ejection using Lyapunov divergence mapping.
  • Astronomical Validation: Verified engine stability through a 12-year simulation of the Sun-Earth-Jupiter system using Astronomical Units and Solar Masses ($G = 4\pi^2$).
  • Visualization: Authored a cinematic rendering suite to visualize "Butterfly Effect" divergence and total system collapse.

A structural migration of a 2023 procedural Fortran 90 dissertation into a high-performance, vectorized Python framework.

  • Numerical Validation: Verified custom RK4 algorithms against SciPy, achieving a maximum residual error of $< 10^{-7}$.
  • Legacy Cross-Validation: Achieved 100% trace overlap between modern Python outputs and legacy Fortran data.
  • Performance Auditing: Benchmarked Python interpreter loops versus compiled Fortran for 1,000,000-step execution cycles.

An investigation of ballistics kinematics evaluating the transit from idealized vacuum baselines to dissipative media.

$$ m \frac{d\mathbf{v}}{dt} = m \mathbf{g} - b\mathbf{v} - c|\mathbf{v}|\mathbf{v} $$

  • State-Space Vectorization: Implements array-based evaluations in NumPy to resolve non-linear quadratic drag terms where exact analytical solutions are unavailable.
  • Error Benchmarking: Compares custom discrete step allocations against adaptive-step algorithms to map absolute spatial residuals.

2026 Research Roadmap

Month Project Focus Technical Milestones / Status
Jan Projectile v1.0 Completed • Kinematics, Euler integration, pure Python baseline.
Feb Projectile v2.1 Completed • RK4 Engine development, NumPy vectorization, SciPy validation.
Apr LCR_Modernization Completed • Fortran-to-Python pipeline, profiling, state-space phase mapping.
Apr Chaotic 3-Body Dynamics Completed • Symplectic Velocity-Verlet, Hamiltonian conservation tracking, ejection thresholds.
May Lagrangian Mechanics Completed • Double Pendulum derivation, generalized coordinates, Poincaré sections.
May Lorenz Attractor Completed • Bifurcation mapping, Chaos quantification ($\lambda_{max}$), 3D phase topology.
June Computational Linear Algebra Next Up • Matrix Mechanics, Eigenvalue problems, Lanczos algorithm, and Normal Mode analysis.

Computational Methodologies

My technical stack maps directly to strict methodological requirements designed for reproducible execution on standard consumer hardware (16 GB RAM, CPU-only):

  • Numerical Integration: Symplectic algorithms (Leapfrog/Verlet) and adaptive high-order solvers (RK45, DOP853).
  • State-Space Modeling: Vectorized array operations using NumPy and SciPy for multi-variable ODEs.
  • Chaotic Quantification: Implementation of phase-space metrics, including Lyapunov exponents and Poincaré mapping.
  • Physics Validation: Test-driven workflows designed to verify structural invariants (e.g., energy and momentum conservation) during runtime.
  • Environment Reproducibility: Strict adherence to deterministic random seed controls and continuous versioning for repository continuity.

The Research Trajectory

Consolidated Knowledge I have verified my capacity to construct vectorized ODE solvers for many-body and chaotic systems. I can successfully track structural conservation laws directly within computation loops, quantify non-linear trajectories using established chaos indicators, and enforce mathematical accuracy over millions of integration steps.

Targeted PhD-Level Methodologies (Future Research Roadmap) To transition from standalone numerical simulations to high-performance, doctoral-level research, I have identified the following computational methodologies as the core technical objectives of my upcoming academic trajectory:

  1. Compiled Acceleration: Migrating computationally intensive components from interpreted Python to compiled frameworks (Numba, native C++ extensions) to bypass interpreter overhead and execute high-speed multi-parameter sweeps.
  2. Dimensional Scaling: Progressing from systems governed by Ordinary Differential Equations (ODEs) to high-dimensional Partial Differential Equations (PDEs) and large many-body lattice matrices.
  3. Parallelization: Implementing multi-core CPU parallelization architectures to manage large-scale computational execution and high-density state-space mapping efficiently.

"Physics is the only profession in which prophecy is not only allowed but required." — This profile tracks my progress in mastering those prophecies through code.

Popular repositories Loading

  1. lorenz-attractor-simulation lorenz-attractor-simulation Public

    A numerical laboratory for mapping dissipative chaos, strange attractors, and bifurcations in the Lorenz system.

    Python 1

  2. rcgiri-physics rcgiri-physics Public

  3. projectile-simulation projectile-simulation Public

    This project is a computational study of classical ballistics. While textbook physics often assumes objects move in a vacuum, real-world motion is significantly altered by air resistance. Because t…

    Python

  4. LCR-Circuit-Modernization LCR-Circuit-Modernization Public

    A comparative computational study of driven LCR circuits: Transitioning legacy Fortran 90 implementations to high-performance vectorized Python/NumPy environments using RK4 integration.

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  5. three-body-simulation three-body-simulation Public

    A computational study on the gravitational interaction of three point-masses in a 2D plane.

    Python

  6. double-pendulum-simulation double-pendulum-simulation Public

    A high-fidelity numerical laboratory for modeling Double Pendulum dynamics using Lagrangian mechanics. Features vectorized Euler-Lagrange solvers, symplectic integration, and bifurcation analysis t…

    Python