Upcoming Seminars
Title: 量子错误缓解
Speaker: 李颖 副教授 (中国工程物理研究院研究生院)
Time: 待定
Place: 物理所M楼830
计算只有在产生正确结果时才有用。在具有数百万个量子比特的可扩展量子计算机上,我们可以通过使用量子纠错码保护信息来获得正确的计算结果。然而,这种大规模的量子纠错在近期内不太可能实现。量子错误缓解是实现精确量子计算的另一类方法。因为不需要大量的量子比特,量子错误缓解适用于近期的量子计算技术。 在这次报告中,我将介绍量子错误缓解和一些该方向的新进展。

Title: Quantum Error Mitigation via Matrix Product Operators
Speaker: 杨硕 副教授 (清华大学)
Time: 11月25日上午10:30
Place: 物理所M楼830
Abstract:  In the era of noisy intermediate-scale quantum devices, the number of controllable hardware qubits is insufficient to implement quantum error correction. As an alternative, quantum error mitigation (QEM) can suppress errors in measurement results via repeated experiments and postprocessing of data. Typical techniques for error mitigation, e.g., the quasiprobability decomposition method, ignore correlated errors between different gates. Here, we introduce a QEM method based on the matrix product operator (MPO) representation of a quantum circuit that can characterize the noise channel with polynomial complexity. Our technique is demonstrated on a depth=20 fully parallel quantum circuit of up to Nq=20 qubits undergoing local and global noise. The circuit error is reduced by a several-times factor with only a small bond dimension D'=1 for the noise channel. The MPO representation increases the accuracy of modeling noise without consuming more experimental resources, which improves the QEM performance and broadens its scope of application. Our method is hopeful of being applied to circuits in higher dimensions with more qubits and deeper depth.
参考文献: Yuchen Guo and Shuo Yang, PRX Quantum 3, 040313 (2022).
More details can be found in http://seminar.cpsjournals.cn/