qiskit.opflow.evolutions.PauliTrotterEvolution

class PauliTrotterEvolution(trotter_mode='trotter', reps=1)

An Evolution algorithm replacing exponentiated sums of Paulis by changing them each to the Z basis, rotating with an rZ, changing back, and Trotterizing.

More specifically, we compute basis change circuits for each Pauli into a single-qubit Z, evolve the Z by the desired evolution time with an rZ gate, and change the basis back using the adjoint of the original basis change circuit. For sums of Paulis, the individual Pauli evolution circuits are composed together by Trotterization scheme.

Parameters

• trotter_mode (Union[str, TrotterizationBase, None]) – A string (‘trotter’, ‘suzuki’, or ‘qdrift’) to pass to the TrotterizationFactory, or a TrotterizationBase, indicating how to combine individual Pauli evolution circuits to equal the exponentiation of the Pauli sum.

• reps (Optional[int]) – How many Trotterization repetitions to make, to improve the approximation accuracy.

• TODO uncomment when we implement Abelian grouped evolution. (#) –

• group_paulis (#) – Whether to group Pauli sums into Abelian

• sub-groups (#) –

• a single diagonalization circuit can be used for each group (so) –

• rather than each Pauli. (#) –

__init__(trotter_mode='trotter', reps=1)

Parameters

• trotter_mode (Union[str, TrotterizationBase, None]) – A string (‘trotter’, ‘suzuki’, or ‘qdrift’) to pass to the TrotterizationFactory, or a TrotterizationBase, indicating how to combine individual Pauli evolution circuits to equal the exponentiation of the Pauli sum.

• reps (Optional[int]) – How many Trotterization repetitions to make, to improve the approximation accuracy.

• TODO uncomment when we implement Abelian grouped evolution. (#) –

• group_paulis (#) – Whether to group Pauli sums into Abelian

• sub-groups (#) –

• a single diagonalization circuit can be used for each group (so) –

• rather than each Pauli. (#) –

Methods

__init__([trotter_mode, reps])	type trotter_mode Union[str, TrotterizationBase, None]
convert(operator)	Traverse the operator, replacing EvolvedOps with CircuitOps containing Trotterized evolutions equalling the exponentiation of -i * operator.
evolution_for_abelian_paulisum(op_sum)	Evolution for abelian pauli sum
evolution_for_pauli(pauli_op)	Compute evolution Operator for a single Pauli using a PauliBasisChange.

Attributes

trotter

TrotterizationBase used to evolve SummedOps.

convert(operator)

Traverse the operator, replacing EvolvedOps with CircuitOps containing Trotterized evolutions equalling the exponentiation of -i * operator.

Parameters

operator (OperatorBase) – The Operator to convert.

Return type

OperatorBase

Returns

The converted operator.

evolution_for_abelian_paulisum(op_sum)

Evolution for abelian pauli sum

Return type

PrimitiveOp

evolution_for_pauli(pauli_op)

Compute evolution Operator for a single Pauli using a PauliBasisChange.

Parameters

pauli_op (PauliOp) – The PauliOp to evolve.

Return type

PrimitiveOp

Returns

A PrimitiveOp, either the evolution CircuitOp or a PauliOp equal to the identity if pauli_op is the identity.

property trotter

TrotterizationBase used to evolve SummedOps.

Return type

TrotterizationBase