---
title: GMS (v2.1)
description: API reference for qiskit.circuit.library.GMS in qiskit v2.1
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/2.1/qiskit.circuit.library.GMS
---

# GMS

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

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.1/qiskit/circuit/library/generalized_gates/gms.py#L30-L102)

Bases: [`QuantumCircuit`](/docs/api/qiskit/2.1/qiskit.circuit.QuantumCircuit "qiskit.circuit.quantumcircuit.QuantumCircuit")

Global Mølmer–Sørensen gate.

**Circuit symbol:**

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

**Expanded Circuit:**

![Diagram illustrating the previously described circuit.](https://eu-de.quantum.cloud.ibm.com/docs/images/api/qiskit/2.1/qiskit-circuit-library-GMS-1.avif)

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].

$$
GMS(\chi_{12}, \chi_{13}, ..., \chi_{n-1 n}) =
exp(-i \sum_{i=1}^{n} \sum_{j=i+1}^{n} X{\otimes}X \frac{\chi_{ij}}{2})
$$

**References:**

\[1] Sørensen, A. and Mølmer, K., Multi-particle entanglement of hot trapped ions. Physical Review Letters. 82 (9): 1835–1838. [arXiv:9810040](https://arxiv.org/abs/quant-ph/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](https://arxiv.org/abs/1707.06356)

Create a new Global Mølmer–Sørensen (GMS) gate.

> **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*](https://docs.python.org/3/library/functions.html#int)) – width of gate.
- **theta** ([*list*](https://docs.python.org/3/library/stdtypes.html#list)*\[*[*list*](https://docs.python.org/3/library/stdtypes.html#list)*\[*[*float*](https://docs.python.org/3/library/functions.html#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**

```python
from qiskit import QuantumCircuit

qc = QuantumCircuit(2, 2, name="my_circuit")
print(qc.name)
```

```text
my_circuit
```