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class EvolutionProblem(hamiltonian, time, initial_state=None, aux_operators=None, truncation_threshold=1e-12, t_param=None, param_value_dict=None)

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Bases: object

Pending deprecation: Evolution problem class.

The EvolutionProblem class has been superseded by the qiskit.algorithms.time_evolvers.TimeEvolutionProblem class. This class will be deprecated in a future release and subsequently removed after that.

This class is the input to time evolution algorithms and must contain information on the total evolution time, a quantum state to be evolved and under which Hamiltonian the state is evolved.


  • hamiltonian (OperatorBase) – The Hamiltonian under which to evolve the system.
  • time (float) – Total time of evolution.
  • initial_state (Union[StateFn, QuantumCircuit, None]) – The quantum state to be evolved for methods like Trotterization. For variational time evolutions, where the evolution happens in an ansatz, this argument is not required.
  • aux_operators (Union[List[Optional[OperatorBase]], Dict[str, OperatorBase], None]) – Optional list of auxiliary operators to be evaluated with the evolved initial_state and their expectation values returned.
  • truncation_threshold (float) – Defines a threshold under which values can be assumed to be 0. Used when aux_operators is provided.
  • t_param (Optional[Parameter]) – Time parameter in case of a time-dependent Hamiltonian. This free parameter must be within the hamiltonian.
  • param_value_dict (Optional[Dict[Parameter, complex]]) – Maps free parameters in the problem to values. Depending on the algorithm, it might refer to e.g. a Hamiltonian or an initial state.


ValueError – If non-positive time of evolution is provided.




Checks if all parameters present in the Hamiltonian are also present in the dictionary that maps them to values.


ValueError – If Hamiltonian parameters cannot be bound with data provided.

Return type




Returns time.

Return type


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