tutorials.md

Tutorials

This section summarizes the main supported workflows and points to maintained example scripts.

Many-body custom Hamiltonian

• Build a HilbertSpace on a lattice.
• Create a Hamiltonian and add terms through operator factories.
• Build the sparse or dense matrix.
• Diagonalize and inspect the low-energy spectrum.

Reference example:

• examples/algebra/example_hilbert_and_custom_hamiltonian.py

Quadratic single-particle workflow

• Construct a QuadraticHamiltonian.
• Add onsite, hopping, or pairing terms.
• Build either the single-particle matrix or the full BdG matrix.
• Use diagonalizing_bogoliubov_transform for the Qiskit-style orbital transform.
• Use to_qiskit_hamiltonian, from_qiskit_hamiltonian, or from_openfermion_hamiltonian for external interoperability when optional dependencies are installed.

Reference example:

• examples/algebra/example_quadratic_single_particle.py

Density matrix and entropy workflow

• Build reduced density matrices with general_python.physics.density_matrix.
• Compute von Neumann or Renyi entropies with general_python.physics.entropy.
• Compute mutual information between sites.

Reference example:

• examples/physics/example_entropy_density_matrix.py

Time evolution and spectral statistics

• Diagonalize a Hamiltonian.
• Use ham.time_evo for evolved states.
• Compute level-spacing diagnostics with gap_ratio.

Reference example:

• examples/physics/example_time_evolution_and_spectral_stats.py

Lattice-driven construction

• Use SquareLattice or HoneycombLattice.
• Extract neighbors directly from the lattice.
• Feed those bonds into Hamiltonian assembly.

Reference example:

• examples/workflows/example_lattice_driven_hamiltonian.py