Efficient Magic State Distillation by Zero-Level Distillation

Magic state distillation (MSD) is an essential element for universal fault-tolerant quantum computing, which distills a high-fidelity magic state from noisy magic states using ideal (error-corrected) Clifford operations. For ideal Clifford operations, it needs to be performed on the logical qubits a...

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Bibliographic Details
Main Authors: Tomohiro Itogawa, Yugo Takada, Yutaka Hirano, Keisuke Fujii
Format: Article
Language:English
Published: American Physical Society 2025-06-01
Series:PRX Quantum
Online Access:http://doi.org/10.1103/thxx-njr6
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Summary:Magic state distillation (MSD) is an essential element for universal fault-tolerant quantum computing, which distills a high-fidelity magic state from noisy magic states using ideal (error-corrected) Clifford operations. For ideal Clifford operations, it needs to be performed on the logical qubits and hence incurs a large spatiotemporal overhead, which is one of the major bottlenecks for the realization of fault-tolerant quantum computers (FTQCs). Here we propose zero-level distillation, which prepares a high-fidelity logical magic state at the physical level, namely zero level, using physical qubits and nearest-neighbor two-qubit gates on a square lattice. We develop a zero-level distillation circuit and show that distillation can be made even more efficient than the conventional sophisticated approaches with logical level distillations. The key idea involves the Knill et al.-type distillation using the Steane code and its careful mapping to the square-lattice architecture with error detection. The distilled magic state on the Steane-code state is then teleported or converted to surface codes. We numerically find that the error rate of the logical magic state scales as approximately 100×p^{2} in terms of the physical error rate p. For example, with a physical error rate of p=10^{−4} (10^{−3}), the logical error rate is reduced to p_{L}=10^{−6} (10^{−4}), resulting in an improvement of 2 (1) orders of magnitude. This contributes to reducing both space and time overhead for early FTQC as well as full-fledged FTQC combined with conventional multilevel distillation protocols.
ISSN:2691-3399