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IBM Quantum Platform

GMS

class qiskit.circuit.library.GMS(num_qubits, theta)

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Bases: QuantumCircuit

Global Mølmer–Sørensen gate.

Circuit symbol:

     ┌───────────┐
q_0: ┤0          ├
     │           │
q_1: ┤1   GMS    ├
     │           │
q_2: ┤2          ├
     └───────────┘

Expanded Circuit:

Diagram illustrating the previously described circuit.

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(theta) interaction, and is thus reduced to the RXXGate. The global MS gate is a sum of XX interactions on all pairs [2].

GMS(χ12,χ13,...,χn1n)=exp(ii=1nj=i+1nXXχij2)GMS(\chi_{12}, \chi_{13}, ..., \chi_{n-1 n}) = exp(-i \sum_{i=1}^{n} \sum_{j=i+1}^{n} X{\otimes}X \frac{\chi_{ij}}{2})

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

Deprecated since version 2.1

The class qiskit.circuit.library.generalized_gates.gms.GMS is deprecated as of Qiskit 2.1. It will be removed in Qiskit 3.0. Use the MSGate instead.

Parameters

  • num_qubits (int) – width of gate.
  • theta (list[list[float]] | np.ndarray) – a num_qubits x num_qubits symmetric matrix of interaction angles for each qubit pair. The upper triangle is considered.

Attributes

name

Type: str

A human-readable name for the circuit.

Example

from qiskit import QuantumCircuit
 
qc = QuantumCircuit(2, 2, name="my_circuit")
print(qc.name)
my_circuit
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