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arXiv · 2603.14202

Multi-qubit controlled gate with optimal T-count

Soichiro Yamazaki·Seiseki Akibue
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Abstract

Controlled gates are key components in various quantum algorithms. Improving on the prior work of Gosset et al., we show that, for an allowed error $\varepsilon$, $3\log_2(1/\varepsilon) + o(\log(1/\varepsilon))$ $T$ gates are sufficient to approximate most multi-qubit controlled SU(2)s. We also show that this T-count matches the lower bound when the use of an almost controlled gate is prohibited. As an application, general controlled gate synthesis and efficient SU(4) gate synthesis are given.

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Soichiro Yamazaki, Seiseki Akibue. 2026-03-15. Multi-qubit controlled gate with optimal T-count. https://arxiv.org/abs/2603.14202

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