Qubit Nodes

Qubit

This node can be used to improve & simplify the visual structure of the quantum flow.

This node can help identifying which wire correspond to which qubit, and enhancing the circuit readability in case of large flows and overlapping nodes.

This node does not affect the state of the input qubit. It only displays the qubit label under the node and passes the qubit as output.

Input

Output

Reset

This node resets a qubit back to its initial state: the 0 state.

Input

Output

Reset qubit - Qiskit documentation

Barrier

This node can be used to control the order in which quantum gates are applied accross multiple qubits. It can also be used to visually differentiate qubits objects when they flow through the same wire.

The barrier will wait until a specified number of qubit objects have arrived to the node, before they are sent further along in the quantum circuit.

To do this, open the node properties and select the number of qubits objects that the barrier node will be expecting, before allowing them to continue running.

Input

Output

Barrier - Qiskit documentation

SWAP

The SWAP node swaps the states of the two input qubits. Each qubit will keep the same label but will end up in the other qubit's state.

This node is mostly used for technical quantum backend reasons such as applying a multiple qubits gate on two qubits that are physically too far in the quantum backend.

Such considerations are automatically handled by the quantum computing language to apply SWAP gates acccordingly, so that the user does not have to worry about the physical position of qubits.

Input

Output

SWAP gate - Qiskit textbook
SWAP gate - Qiskit documentation