Multiple cuts

Performing multiple cuts works the exact same way as a single cut. Since eats cut introduces an extra qubit one just has to be careful to properly allocate the extra qubits needed by wire-cutting.

Cutting to more than two parts

1: Define the circuit we want to cut

circuit = QuantumCircuit(4)
circuit.h(0)
circuit.cx(0,1)
circuit.cx(1,2)
circuit.cx(2,3)
circuit.measure_all()

circuit.draw("mpl")

Now let’s say we want to cut this circuit into three pieces with two cuts.

2: Insert cut_wire operations to the circuit to denote where we want to cut the circuit

cut_circuit = QuantumCircuit(4)
 cut_circuit.h(0)
 cut_circuit.cx(0,1)
 cut_circuit.append(cut, [1])
 cut_circuit.cx(1,2)
 cut_circuit.append(cut, [2])
 cut_circuit.cx(2,3)

cut_circuit.draw("mpl")

3: Continue like with single cut

backend = AerSimulator()
observables = [0,1,2, [0,2]]

estimated_expectation_values = ck.run(cut_circuit, observables, backend)

Click here to download example notebook.

More examples on how the cuts should be placed.

1: Cutting two subsequent wires

Initial circuit:

circuit = QuantumCircuit(4)
circuit.h(0)
circuit.cx(0,1)
circuit.cx(0,2)
circuit.cx(1,2)
circuit.cx(1,3)
circuit.measure_all()

circuit.draw("mpl")

Circuit with cuts:

cut_circuit = QuantumCircuit(4)
cut_circuit.h(0)
cut_circuit.cx(0,1)
cut_circuit.cx(0,2)
cut_circuit.append(cut, [1])
cut_circuit.append(cut, [2])
cut_circuit.cx(1,2)
cut_circuit.cx(1,3)

cut_circuit.draw("mpl")

Click here to download example notebook.

2: Two consequent cuts on the same wire

Initial circuit:

circuit = QuantumCircuit(3)
circuit.h(0)
circuit.cx(0,1)
circuit.cx(1,2)
circuit.cx(0,1)
circuit.measure_all()

circuit.draw("mpl")

Circuit with cuts:

cut_circuit = QuantumCircuit(3)
cut_circuit.h(0)
cut_circuit.cx(0,1)
cut_circuit.append(cut, [1])
cut_circuit.cx(1,2)
cut_circuit.append(cut, [1])
cut_circuit.cx(0,1)

cut_circuit.draw("mpl")

Click here to download example notebook.