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Quantum Synth

Hear the H₂ Molecule

The simplest molecule. Two protons, two electrons, one covalent bond. Each energy level becomes a harmonic partial. Stretch the bond and hear the spectrum shift.

STO-3G basis·4 qubits (Jordan-Wigner)·11 unique levels·Full diagonalization
Energy Levels47–232 Hz
Spectrogram65–214 Hz
H
H
0.74 Åequilibrium
0.3 Å compressed 0.74 Å3 Å dissociated
1.5

Thermal weighting (Ha)

65 Hz

Ground state pitch

1.2 Ha/oct

Harmonic spacing

35%
11/11 levels

Harmonic Layers

How It Works

Energy Frequency

Each energy eigenvalue of H₂ maps to an oscillator. The gap from ground state sets the pitch: f = 65 × 2ΔE/1.2. These are the same transitions spectroscopists measure with light — now mapped to sound.

Boltzmann Weighting

Amplitude follows a thermal distribution: a = eΔE/kT. Low excitation emphasizes the fundamental. Crank it up and all levels contribute equally — like heating the molecule.

Bond Stretching

Pull the atoms apart and listen. Near equilibrium (0.74 Å), the ground state is deepest. At dissociation, energy levels converge and the harmonic structure collapses — the sound of a bond breaking.

Technical Details

Hamiltonian: H₂ in STO-3G minimal basis, Jordan-Wigner encoding on 4 qubits (16×16 matrix).

Eigenvalues: Full diagonalization (numpy.linalg.eigvalsh) at 28 bond distances from 0.3 to 3 Å.

Degeneracies arise from symmetry: orbital angular momentum, spin. H₂ has 4 spin-orbitals giving 16 eigenvalues, typically 9-10 unique levels.

Computed with PySCF + OpenFermion. Same pipeline used for our VQE hardware experiments on Tuna-9 and IBM Quantum.