Fusion-based quantum computation

• Published in: Nature communications Vol. 14; no. 1; p. 912
• Main Authors: Bartolucci, Sara, Birchall, Patrick, Bombín, Hector, Cable, Hugo, Dawson, Chris, Gimeno-Segovia, Mercedes, Johnston, Eric, Kieling, Konrad, Nickerson, Naomi, Pant, Mihir, Pastawski, Fernando, Rudolph, Terry, Sparrow, Chris
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17.02.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/483/2802; 639/766/483/481; Computer applications; Error correction; Fault tolerance; Gates; Humanities and Social Sciences; multidisciplinary; Photonics; Photons; Quantum computing; Quantum entanglement; Quantum phenomena; Qubits (quantum computing); Science; Science (multidisciplinary); Statistical analysis
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-36493-1

The standard primitives of quantum computing include deterministic unitary entangling gates, which are not natural operations in many systems including photonics. Here, we present fusion-based quantum computation, a model for fault tolerant quantum computing constructed from physical primitives readily accessible in photonic systems. These are entangling measurements, called fusions, which are performed on the qubits of small constant sized entangled resource states. Probabilistic photonic gates as well as errors are directly dealt with by the quantum error correction protocol. We show that this computational model can achieve a higher threshold than schemes reported in literature. We present a ballistic scheme which can tolerate a 10.4% probability of suffering photon loss in each fusion, which corresponds to a 2.7% probability of loss of each individual photon. The architecture is also highly modular and has reduced classical processing requirements compared to previous photonic quantum computing architectures. Fusion gates are common operations in photonic quantum information platforms, where they are employed to create entanglement. Here, the authors propose a quantum computation scheme where the same measurements used to generate entanglement can also be used to achieve fault-tolerance leading to an increased tolerance to errors.