PauliTrotterEvolution

class PauliTrotterEvolution(trotter_mode='trotter', reps=1)[source]

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.

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

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

  • sub-groups (#) –

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

  • Pauli. (# rather than each) –

Attributes

PauliTrotterEvolution.trotter

TrotterizationBase used to evolve SummedOps.

Methods

PauliTrotterEvolution.convert(operator)

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

PauliTrotterEvolution.evolution_for_abelian_paulisum(op_sum)

Evolution for abelian pauli sum

PauliTrotterEvolution.evolution_for_pauli(…)

Compute evolution Operator for a single Pauli using a PauliBasisChange.