In a comprehensive review paper on quantum error mitigation by Cai et al. (arXiv:2210.00921), the authors posed an open problem: what is the full landscape of the “zoo” of QEM techniques? I recently launched a website to help address this: the QEM Zoo. It’s a living catalog of quantum error mitigation and suppression techniques, inspired by the Complexity Zoo and the Error Correction Zoo. The site organizes techniques into protocols, supporting methods, noise models, and applications—all searchable and filterable.

In a previous post, I gave a high-level overview of zero-noise extrapolation (ZNE) and how we can increase the noise of quantum circuits for ZNE using a technique known as quantum circuit unoptimization. In this post, I’ll describe a technique that my colleague Andrea Mari and I came up with called layerwise Richardson extrapolation (LRE), which can be thought of as a generalization of standard ZNE. The paper can be found on arXiv (arXiv:2402.

While quantum computers have continued to improve over the past few years, it’s a known issue that error rates cannot be made low enough simply by improvements to the hardware. One approach to this problem is the domain of quantum error correction (QEC) which promises fault-tolerant devices that properly deals with the issue of noise. While the theory of QEC is well-established, the implementation of the theory is still a while away from being physically realizable.