Hamiltonian

A HamiltonianProblem asks for the spectrum of a Hermitian operator.

Usage

from microquantum import HamiltonianProblem, Operator

problem = HamiltonianProblem(Operator.Z(), name="z-spectrum")
print(problem.hamiltonian)             # Operator.Z()
print(problem.validate())              # []

data = problem.to_dict()               # labeled Pauli / matrix encoding
print(data["type"])                    # "Hamiltonian"

restored = HamiltonianProblem(
    hamiltonian=Operator.from_dict(data["hamiltonian"]),
    name=data["name"],
)

Hamiltonians

The Hamiltonian may be:

• a full Operator matrix,

• a PauliSum (efficient, matrix-free), or

• built from chemistry tooling — MolecularHamiltonian, H2Hamiltonian, LiHHamiltonian.

Serialization

Hamiltonian-backed problems serialize through hamiltonian_to_dict into labeled Pauli terms with complex coefficients (or an explicit matrix), so a HamiltonianProblem stays storable and shareable.

Solving

EigenvalueProblem (the subclass that also asks for the lowest k eigenvalues) is the form consumed by VQE.