Floor van Riggelen

Authors: F. van Riggelen, W. I. L. Lawrie, M. Russ, N. W. Hendrickx, A. Sammak,
M. Rispler, B. M. Terhal, G. Scappucci, and M. Veldhorst

The fault-tolerant operation of logical qubits is an important requirement for realizing a universal
quantum computer. Spin qubits based on quantum dots have great potential to be scaled to large
numbers because of their compatibility with standard semiconductor manufacturing. On this poster we show that a quantum error correction code can be implemented using a four-qubit array in germanium.
We demonstrate a resonant SWAP gate and by combining controlled-Z and controlled-S−1 gates
we construct a Toffoli-like three-qubit gate. We execute a two-qubit phase flip code and find that
we can preserve the state of the data qubit by applying a refocusing pulse to the ancilla qubit. In
addition, we implement a phase flip code on three qubits, making use of a Toffoli-like gate for the
final correction step. Both the quality and quantity of the qubits will require significant improvement
to achieve fault-tolerance. However, the capability to implement quantum error correction codes gives clear indications on how to improve the properties of our qubits to improve the performance of these type of algorithms.