The sequence starts from encoding the data qubit state to a three-qubit entangled state. 1a) comprises one data qubit (Q 2) to be corrected and two ancilla qubits (Q 1 and Q 3). Silicon-based spin qubits have emerged as a qubit platform in the past decade, and there has been rapid progress in long coherence times 20, 21, high-fidelity universal quantum gates 6, 7, 8, high-temperature operation 22, 23 and generation of three-qubit entanglement 24, 25. Its basic concept has been demonstrated in various platforms, such as nuclear magnetic resonance 9, 15, trapped ions 10, 16, nitrogen vacancy centres 17 and superconducting circuits 11, 18, 19, and has served as an important benchmark of the qubit systems. QEC is a protocol to circumvent this problem by distributing the quantum information across a larger multiqubit entangled state so that the errors can be detected and corrected 14. As the number of qubits increases and/or the computational tasks become more complex, the errors cause exponential reduction of the accuracy of computational results. However, these quantum properties are sensitive to decoherence errors owing to energy relaxation and dephasing. Quantum computing takes advantage of quantum superposition and entanglement to accelerate the computational tasks 12, 13.
These results show successful implementation of QEC and the potential of a silicon-based platform for large-scale quantum computing. As expected, the error correction mitigates the errors owing to one-qubit phase-flip, as well as the intrinsic dephasing mainly owing to quasi-static phase noise. The correction to this encoded state is performed by a three-qubit conditional rotation, which we implement by an efficient single-step resonantly driven iToffoli gate.
#TREE QUANTUM ERROR CORRECTION CODE#
Here we demonstrate a three-qubit phase-correcting code in silicon, in which an encoded three-qubit state is protected against any phase-flip error on one of the three qubits. However, the demonstration of QEC, which requires three or more coupled qubits 1, and involves a three-qubit gate 9, 10, 11 or measurement-based feedback, remains an open challenge. Recent advances in silicon-based qubits have enabled the implementations of high-quality one-qubit and two-qubit systems 6, 7, 8. Among the possible candidate platforms for realizing quantum computing devices, the compatibility with mature nanofabrication technologies of silicon-based spin qubits offers promise to overcome the challenges in scaling up device sizes from the prototypes of today to large-scale computers 3, 4, 5. Future large-scale quantum computers will rely on quantum error correction (QEC) to protect the fragile quantum information during computation 1, 2.
0 kommentar(er)
