ExcitedStatesEigensolver

class ExcitedStatesEigensolver(qubit_mapper, solver)

Bases: ExcitedStatesSolver

The calculation of excited states via an Eigensolver algorithm.

Parameters:

• qubit_mapper (QubitMapper) – The QubitMapper to use for mapping.

• solver (Eigensolver) – Minimum Eigensolver object.

Attributes

solver

Returns the minimum eigensolver.

Methods

get_qubit_operators(problem, aux_operators=None)

Gets the operator and auxiliary operators, and transforms the provided auxiliary operators using a QubitMapper. If the user-provided aux_operators contain a name which clashes with an internally constructed auxiliary operator, then the corresponding internal operator will be overridden by the user-provided operator.

Parameters:

• problem (BaseProblem) – A class encoding a problem defining the qubit operators.

• aux_operators (dict[str, SparseLabelOp | SparsePauliOp] | None) – Additional auxiliary operators to transform.

Returns:

A tuple with the main operator (hamiltonian) and a dictionary of auxiliary default and custom operators.

Return type:

tuple[SparsePauliOp, dict[str, SparsePauliOp] | None]

solve(problem, aux_operators=None)

Compute Ground and Excited States properties.

Parameters:

• problem (BaseProblem) – A class encoding a problem to be solved.

• aux_operators (dict[str, SparseLabelOp | SparsePauliOp] | None) – Additional auxiliary operators to evaluate.

Returns:

An interpreted EigenstateResult. For more information see also interpret().

Return type:

EigenstateResult