MSGate
class qiskit.circuit.library.MSGate(num_qubits, theta, label=None)
Bases: Gate
The Mølmer–Sørensen gate.
The Mølmer–Sørensen gate is native to ion-trap systems. The global MS can be applied to multiple ions to entangle multiple qubits simultaneously [1].
In the two-qubit case, this is equivalent to an XX interaction, and is thus reduced to the RXXGate
. The global MS gate is a sum of XX interactions on all pairs [2].
Example:
import numpy as np
from qiskit.circuit.library import MSGate
from qiskit.quantum_info import Operator
gate = MSGate(num_qubits=3, theta=[[0, np.pi/4, np.pi/8],
[0, 0, np.pi/2],
[0, 0, 0]])
print(Operator(gate))
References:
[1] Sørensen, A. and Mølmer, K., Multi-particle entanglement of hot trapped ions. Physical Review Letters. 82 (9): 1835–1838. arXiv:9810040
[2] Maslov, D. and Nam, Y., Use of global interactions in efficient quantum circuit constructions. New Journal of Physics, 20(3), p.033018. arXiv:1707.06356
Parameters
- num_qubits (int) – The number of qubits the MS gate acts on.
- theta (ParameterValueType | Sequence[Sequence[ParameterValueType]]) – The XX rotation angles. If a single value, the same angle is used on all interactions. Alternatively an upper-triangular, square matrix with width
num_qubits
can be provided with interaction angles for each qubit pair. - label (str | None) – A gate label.
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 behavioral 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 parametrized gate with a particular set of parameters for the purposes of distinguishing it in a Target
from the full parametrized 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
True
In 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.
The property qiskit.circuit.instruction.Instruction.condition
is deprecated as of qiskit 1.3.0. It will be removed in 2.0.0.
condition_bits
Get Clbits in condition.
The property qiskit.circuit.instruction.Instruction.condition_bits
is deprecated as of qiskit 1.3.0. It will be removed in 2.0.0.
decompositions
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
definition
Return definition in terms of other basic gates.
duration
Get the duration.
The property qiskit.circuit.instruction.Instruction.duration
is deprecated as of qiskit 1.3.0. It will be removed in Qiskit 2.0.0.
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
The parameters of this Instruction
. Ideally these will be gate angles.
unit
Get the time unit of duration.
The property qiskit.circuit.instruction.Instruction.unit
is deprecated as of qiskit 1.3.0. It will be removed in Qiskit 2.0.0.