Córcoles A D, Magesan Easwar, Srinivasan Srikanth J, Cross Andrew W, Steffen M, Gambetta Jay M, Chow Jerry M
IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Nat Commun. 2015 Apr 29;6:6979. doi: 10.1038/ncomms7979.
The ability to detect and deal with errors when manipulating quantum systems is a fundamental requirement for fault-tolerant quantum computing. Unlike classical bits that are subject to only digital bit-flip errors, quantum bits are susceptible to a much larger spectrum of errors, for which any complete quantum error-correcting code must account. Whilst classical bit-flip detection can be realized via a linear array of qubits, a general fault-tolerant quantum error-correcting code requires extending into a higher-dimensional lattice. Here we present a quantum error detection protocol on a two-by-two planar lattice of superconducting qubits. The protocol detects an arbitrary quantum error on an encoded two-qubit entangled state via quantum non-demolition parity measurements on another pair of error syndrome qubits. This result represents a building block towards larger lattices amenable to fault-tolerant quantum error correction architectures such as the surface code.
在操纵量子系统时检测和处理错误的能力是容错量子计算的一项基本要求。与仅受数字位翻转错误影响的经典比特不同，量子比特容易受到范围更广的错误影响，任何完整的量子纠错码都必须考虑到这些错误。虽然经典位翻转检测可以通过量子比特的线性阵列实现，但一般的容错量子纠错码需要扩展到更高维的晶格中。在此，我们展示了一种基于超导量子比特的二乘二平面晶格的量子错误检测协议。该协议通过对另一对错误征兆量子比特进行量子非破坏奇偶性测量，来检测编码的两比特纠缠态上的任意量子错误。这一结果代表了迈向适用于诸如表面码等容错量子纠错架构的更大晶格的一个构建模块。
