Supplementary data and code for: "Probing the Ground State of the Antiferromagnetic Heisenberg Model on the Kagome Lattice using Geometrically Informed Variational Quantum Eigensolver"

This repository contains the data and analysis code accompanying the paper "Probing theGround State of the Antiferromagnetic Heisenberg Model on the Kagome Lattice usingGeometrically Informed Variational Quantum Eigensolver" (arXiv:2509.18029). We investigate the ground state of the antiferromagnetic Heisenberg model on the twofundamental kagome-lattice cells — a triangle and a star — using the variational quantumeigensolver (VQE) algorithm executed on real IBM quantum hardware (Oslo, Kyoto, Torino, andAlgiers). Our custom, geometrically informed ansatz uses a shallow hardware-efficientcircuit with a naturally Euclidean parameter space, derived from the Fubini-Study metric toensure a singularity-free landscape. With this ansatz, an adaptive gradient descent (AGD)optimizer achieves faster convergence than simultaneous perturbation stochasticapproximation (SPSA). The ansatz accurately recovers spin-spin correlations and the staticstructure factor without explicit error mitigation, and these observables are shown to beresilient to hardware noise. We further evaluate zero-noise extrapolation (ZNE) andqubit-wise readout error mitigation (REM), and discuss the conditions under which eachtechnique preserves the Rayleigh-Ritz variational principle. The repository includes raw QPU measurement data from all experiments, scripts toreconstruct VQE optimization trajectories (per-epoch energies, gradients, line-searchsteps), and post-processing scripts for ZNE and REM analysis.