Does "Peaked quantum advantage using error correction" support public verification of quantumness?

Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Stack Overflow for Teams is now called Stack Internal. Bring the best of human thought and AI automation together at your work. Bring the best of human thought and AI automation together at your work. Learn more Stack InternalKnowledge at workBring the best of human thought and AI automation together at your work.Peaked quantum advantage using error correction by Deshpande et al. (arXiv link) is a recent, October 2025 entry in the program of designing interactive proofs of quantumness. The proposal combines CSS coding theory with the complexity-theoretic guarantees of instantaneous quantum polynomial-time (IQP) sampling.The way I read the paper, Alice the classical skeptic determines $C_X$ at the same time as getting generators for $C_Z$, only with the requirement that $C_Z^\perp\subset C_X$. But Alice does not appear to have to commit to $C_X$ before Bob the purported quantum computer runs his experiment, as far as I can tell. So, what's stopping her, or really anyone else, from choosing their own $C_Z$ with $C_Z^\perp\subset C_X$ after $C_X$ is announced, and indeed after Bob has run his quantum experiments to generate the strings?Can't classical Charlie, upon seeing the conversation between Alice and Bob, take (1) Alice's descriptions of $U(\theta)$ and $C_Z$ that she gave to Bob, (2) take the output strings generated by Bob, (3) find his own perpendicular codewords $C_X^\prime$, (4) and run peakness tests using $C_X^\prime$ instead?If so, then I interpret Charlie as a source of public re-verification of quantumness (?)Yes, Alice can choose her codeword after committing to Bob; indeed Charlie anyone else can as well. See comment 51 from Soumik Ghosh - one of the authors of the paper. Charlie would still have to engage in the somewhat expensive calculations of cross-entropy, though.Thanks for contributing an answer to Quantum Computing Stack Exchange!But avoid …Use MathJax to format equations. MathJax reference.To learn more, see our tips on writing great answers.Required, but never shown By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy. Start asking to get answersFind the answer to your question by asking.Explore related questionsSee similar questions with these tags.To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Site design / logo © 2025 Stack Exchange Inc; user contributions licensed under CC BY-SA . rev 2025.11.21.37165