Virtual Channel Purification

• URL: http://arxiv.org/abs/2402.07866v2
• Date: Fri, 16 Aug 2024 10:46:11 GMT
• Title: Virtual Channel Purification
• Authors: Zhenhuan Liu, Xingjian Zhang, Yue-Yang Fei, Zhenyu Cai,
• Abstract summary: We develop the virtual channel purification protocol, which consumes similar qubit and gate resources as virtual state purification. It offers stronger error suppression with increased system size and more noisy operation copies. It can also be adapted to key tasks in quantum networks like channel capacity activation and entanglement distribution.
• Score: 3.0949746731814
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Quantum error mitigation is a key approach for extracting target state properties on state-of-the-art noisy machines and early fault-tolerant devices. Using the ideas from flag fault tolerance and virtual state purification, we develop the virtual channel purification (VCP) protocol, which consumes similar qubit and gate resources as virtual state purification but offers stronger error suppression with increased system size and more noisy operation copies. Furthermore, VCP removes most of the assumptions required in virtual state purification. Essentially, VCP is the first quantum error mitigation protocol that does not require specific knowledge about the noise models, the target quantum state, and the target problem while still offering rigorous performance guarantees for practical noise regimes. Further connections are made between VCP and quantum error correction to produce the virtual error correction (VEC) protocol, one of the first protocols that combine quantum error correction (QEC) and quantum error mitigation beyond concatenation. VEC can virtually remove all correctable noise in the channel while paying only the same sampling cost as low-order purification. It can achieve QEC-level protection on an unencoded register when transmitting it through a noisy channel, removing the associated encoding qubit overhead. Another variant of VEC can mimic the error suppression power of the surface code by inputting only a bit-flip and a phase-flip code. Our protocol can also be adapted to key tasks in quantum networks like channel capacity activation and entanglement distribution.

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