中央研究院 資訊科學研究所

Fault-tolerant quantum computation (FTQC) schemes using multi-qubit large block codes require a huge amount of clean ancilla states of different types with weak error correlation inside each block. These ancilla states are usually logical stabilizer states of the data code blocks, which are generally difficult to prepare if code size is large. Meanwhile, the yield rates of preparation processes are typically extremely low when the distance of block code is large. Here, we propose a protocol to distil various of ancilla states necessarily for FTQC fault-tolerantly using classical codes. Analytical analysis shows that correlated errors can be largely removed. At the same time, the yield rate can be high for general large block code with arbitrary size, using proper classical codes. Preparation ancilla state for [[23,1,7]] quantum Golay code is numerically studied in detail through Monte Carlo simulation. The results support the validity of the protocol when gate failure rate is reasonably low.