H₂ Ground State (VQE)
Educational demonstration. Hamiltonian coefficients are precomputed and tabulated, not calculated in-browser. Limited to H₂ in a minimal basis with a two-qubit reduction.
These coefficients are a self-constructed approximate model, not reproduced from a published ab initio table — no verified source was available in this environment. They are calibrated so the exact ground-state energy matches the standard H₂/STO-3G equilibrium value of about −1.137 Hartree near R = 0.735 Å, a widely-established reference point in quantum chemistry, not a citation to a specific paper.
Bond length 0.73 angstrom; energy -0.45395 Hartree; error 0.68305.
Learning mode
Find the molecule's lowest energy
VQE is tuning an instrument until the molecule's energy note is as low as possible.
Move theta by hand first, then press Optimize and compare the exact reference.
Definitions on demand
Hamiltonian
The operator encoding the model's energy terms at a selected bond length.
Ansatz
A parameterized family of trial quantum states searched by VQE.
Variational bound
A trial state's expected energy cannot be below the exact ground energy of the same modeled Hamiltonian.
Molecular geometry
E(θ) Curve
Potential Energy Surface — VQE (accent) vs. exact (dashed)