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arXiv · 2411.13142

Measurement-free code-switching for low overhead quantum computation using permutation invariant codes

Yingkai Ouyang·Yumang Jing·Gavin K. Brennen
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Abstract

Transversal gates on quantum error correction codes have been a promising approach for fault-tolerant quantum computing, but are limited by the Eastin-Knill no-go theorem. Existing solutions like gate teleportation and magic state distillation are resource-intensive. We present a measurement-free code-switching protocol for universal quantum computation, switching between a stabiliser code for transversal Cliffords and a permutation-invariant (PI) code for transversal non-Cliffords that are logical $Z$ rotations for any rational multiple of $π$. The novel non-Clifford gates enabled by this code-switching protocol provide for a lower gate count implementation of a universal gate set relative to the Clifford$+T$ gate set. To achieve this, we present a protocol for performing controlled-NOTs between the codes using near-term quantum control operations that employ a catalytic bosonic mode. We also present a new class of PI codes with tunable code distance, supporting transversal non-Clifford gates, and demonstrate their reduced gate count overhead relative to a comparable stabilizer code to stabilizer code switching scheme.

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Yingkai Ouyang, Yumang Jing, Gavin K. Brennen. 2025-09-16. Measurement-free code-switching for low overhead quantum computation using permutation invariant codes. https://doi.org/10.1103/p28m-hb6x

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