HarmonicBasis
class HarmonicBasis(watson_hamiltonian, basis, truncation_order=3)
Bases: qiskit.chemistry.components.bosonic_bases.bosonic_basis.BosonicBasis
Basis in which the Watson Hamiltonian is expressed.
This class uses the Hermite polynomials (eigenstates of the harmonic oscillator) as a modal basis for the expression of the Watson Hamiltonian or any bosonic operator.
References
[1] Ollitrault Pauline J., Chemical science 11 (2020): 6842-6855.
Parameters
- watson_hamiltonian (
WatsonHamiltonian) – AWatsonHamiltonianobject which contains the hamiltonian information. - basis (
List[int]) – Is a list defining the number of modals per mode. E.g. for a 3 modes system with 4 modals per modebasis = [4, 4, 4]. - truncation_order (
int) – where is the Hamiltonian expansion truncation (1 for having only 1-body terms, 2 for having on 1- and 2-body terms…)
Methods
convert
HarmonicBasis.convert(threshold=1e-06)
This prepares an array object representing a bosonic hamiltonian expressed in the harmonic basis. This object can directly be given to the BosonicOperator class to be mapped to a qubit hamiltonian.
Parameters
threshold (float) – the matrix elements of value below this threshold are discarded
Return type
List[List[Tuple[List[List[int]], float]]]
Returns
List of modes for input to creation of a bosonic hamiltonian in the harmonic basis
Raises
ValueError – If problem with order value from computed modes