Hybrid and Fusion Approach for Fault-tolerant Quantum Computing

Quantum error correction is an essential tool for performing reliable quantum information processing tasks under noisy circumstances, and is attracting growing attention today as a crucial element for realizing the fault-tolerant quantum computer. In this article, we introduce two cutting-edge quantum error correction techniques for implementing fault-tolerant quantum computation: the hybrid approach and the fusion-based quantum computation. The hybrid quantum computing utilizes hybrid qubits which combine the advantages of continuous-variable and discrete-variable qubits. The fusion-based quantum error correction offers a way, specialized for photonic quantum information processing, toward fault tolerance based on two-qubit measurement, known as fusion. We demonstrate by numerical simulations that our methods achieve the increased loss threshold and the improved resource efficiency compared to previous photonic proposals.