Quantum circuit execution with spare qubits for state integrity using phase shift and delay

A method, comprising:

• executing, by a system comprising at least one processor, an operation on a group of qubits, the group comprising a first, active qubit subgroup and a second, spare qubit subgroup;
• controlling, by the system, respective variable phase shifts of respective spare qubits of the spare qubit subgroup;
• obtaining, by the system, first measurement data based on the operation as executed on the first, active qubit subgroup;
• obtaining, by the system, respective second measurement data based on the operation as executed on the respective spare qubits of the spare qubit subgroup;
• and
• verifying, by the system, a quantum state integrity, corresponding to the executing of the operation on the group of qubits, based on the first measurement data and the respective second measurement data.

A non-transitory machine-readable medium, comprising executable instructions that, when executed by at least one processor, facilitate performance of operations, the operations comprising:

• applying a first quantum gate to a photon source to place a first qubit into superposition;
• applying a second quantum gate coupled to the first qubit to entangle the first qubit with a second qubit;
• applying a third quantum gate coupled to the first qubit to entangle the first qubit with a third qubit;
• applying a controlled first phase shift to the third qubit;
• applying a controlled first rotation to the third qubit;
• applying a controlled second phase shift to a fourth qubit;
• applying a controlled second rotation to the fourth qubit;
• applying a fourth quantum gate, coupled to the first qubit and the second qubit, to determine a state of the fourth qubit based on the first qubit and the second qubit;
• obtaining first measurement data representative of a first final state of the first qubit;
• obtaining second measurement data representative of a second final state of the second qubit;
• obtaining third measurement data representative of a third final state of the third qubit;
• obtaining fourth measurement data representative of a fourth final state of the fourth qubit;
• and
• validating an accuracy of the first measurement data based on the second measurement data, the third measurement data, and the fourth measurement data.