PauliEvolutionGate
class qiskit.circuit.library.PauliEvolutionGate(operator, time=1.0, label=None, synthesis=None)
Bases: Gate
Time-evolution of an operator consisting of Paulis.
For an operator consisting of Pauli terms and (real) evolution time this gate implements
This gate serves as a high-level definition of the evolution and can be synthesized into a circuit using different algorithms.
The evolution gates are related to the Pauli rotation gates by a factor of 2. For example the time evolution of the Pauli operator is connected to the Pauli rotation by
Examples:
from qiskit.circuit import QuantumCircuit
from qiskit.circuit.library import PauliEvolutionGate
from qiskit.opflow import I, Z, X
# build the evolution gate
operator = (Z ^ Z) - 0.1 * (X ^ I)
evo = PauliEvolutionGate(operator, time=0.2)
# plug it into a circuit
circuit = QuantumCircuit(2)
circuit.append(evo, range(2))
print(circuit.draw())The above will print (note that the -0.1 coefficient is not printed!):
┌──────────────────────────┐
q_0: ┤0 ├
│ exp(-it (ZZ + XI))(0.2) │
q_1: ┤1 ├
└──────────────────────────┘References:
[1] G. Li et al. Paulihedral: A Generalized Block-Wise Compiler Optimization Framework For Quantum Simulation Kernels (2021). [arXiv:2109.03371]
Parameters
- operator (Pauli |PauliOp |SparsePauliOp |PauliSumOp |list) – The operator to evolve. Can also be provided as list of non-commuting operators where the elements are sums of commuting operators. For example:
[XY + YX, ZZ + ZI + IZ, YY]. - time (Union[int, float, ParameterExpression]) – The evolution time.
- label (Optional[str]) – A label for the gate to display in visualizations. Per default, the label is set to
exp(-it <operators>)where<operators>is the sum of the Paulis. Note that the label does not include any coefficients of the Paulis. See the class docstring for an example. - synthesis (Optional[EvolutionSynthesis]) – A synthesis strategy. If None, the default synthesis is the Lie-Trotter product formula with a single repetition.
Attributes
base_class
Get the base class of this instruction. This is guaranteed to be in the inheritance tree of self.
The “base class” of an instruction is the lowest class in its inheritance tree that the object should be considered entirely compatible with for _all_ circuit applications. This typically means that the subclass is defined purely to offer some sort of programmer convenience over the base class, and the base class is the “true” class for a behavioural perspective. In particular, you should not override base_class if you are defining a custom version of an instruction that will be implemented differently by hardware, such as an alternative measurement strategy, or a version of a parametrised gate with a particular set of parameters for the purposes of distinguishing it in a Target from the full parametrised gate.
This is often exactly equivalent to type(obj), except in the case of singleton instances of standard-library instructions. These singleton instances are special subclasses of their base class, and this property will return that base. For example:
>>> isinstance(XGate(), XGate)
True
>>> type(XGate()) is XGate
False
>>> XGate().base_class is XGate
TrueIn general, you should not rely on the precise class of an instruction; within a given circuit, it is expected that Instruction.name should be a more suitable discriminator in most situations.
condition
The classical condition on the instruction.
condition_bits
Get Clbits in condition.
decompositions
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
definition
Return definition in terms of other basic gates.
duration
Get the duration.
label
Return instruction label
mutable
Is this instance is a mutable unique instance or not.
If this attribute is False the gate instance is a shared singleton and is not mutable.
name
Return the name.
num_clbits
Return the number of clbits.
num_qubits
Return the number of qubits.
params
return instruction params.
time
Return the evolution time as stored in the gate parameters.
Returns
The evolution time.
unit
Get the time unit of duration.
Methods
validate_parameter
validate_parameter(parameter)
Gate parameters should be int, float, or ParameterExpression
Return type