Turns out that quantum Tanner codes can have a pretty large distance, even at low length and with generators of weight 6. Would be nice to prove a distance upper bound of n^{2/3}.

The list of accepted papers for #QIP2026 is now online at qip2026.lu.lv/programme/ac...

P ≠ NP in Lean - a milestone in computational vibe complexity! arxiv.org/abs/2510.17829

Est-ce que c’est au même endroit ?

bitch what

The future is here: a formalization in Lean of the generalized quantum Stein's lemma! Amazing that this can be done. arxiv.org/abs/2510.08672

There's no reachable position in chess with more than 218 moves for one player! Here's one with 218 moves for White. This was *not* proved by checking all 8.7 × 10⁴⁵ reachable chess positions. Instead, someone known only to me as Tobs45 figured out a better proof: lichess.org/@/Tobs40/blo...

this is apparently true! en.wikipedia.org/wiki/Taiping...

Stephen Colbert explains why the simplest way of finding the shortest path between 22 cities involves 1. flying to the Moon 2. mining some Helium-3 3. bringing it back to the Earth and pouring it in your quantum computer.

This is interesting and surprising: some Clifford gates cannot be implemented arbitrarily well on arbitrarily good approximate GKP states with Gaussian operations! Nice work by Brenner, Diaz and Koenig arxiv.org/abs/2509.14658 Cat qubits (and generalizations) for the win, I guess ;-)

Can ChatGPT help with research? Maybe not yet for finding new results, but it can certainly speed up some tedious tasks. An example about quantum Tanner codes #qLDPC Working with qudits (d=5) lets you use nice local codes [4,2,3]_5. Then the idea is simply to enumerate small groups and (1/4)

I think this is a very misleading figure. The consensus is that RSA will be broken with proba 1 once a quantum computer is available, but I don't think anybody reasonably expects that all postquantum protocols will eventually get broken. From arxiv.org/abs/2509.13405

We are now at 999 codes. What should be our 1000th? If we pick yours, we will feature you in a post about the code. Comment, reply, message, and spread the word.

The QIP 2026 call for papers is out! QIP 2026 will be held in Riga, Latvia from January 24–30, 2026. See you there! qip2026.lu.lv

In what senses is the quote true or useful? One thing I like about it is that it takes for granted that the listener (me!) can work on great ideas, make a great contribution. Most work doesn't even try. But it's worth trying. The sentiment makes me want to set my sights higher.

Come for the iconic papers and eye-wateringly beautiful textbooks, stay for the stories "from the trenches" (of which I hope John posts more of!). Keep writing, @johnwatrous.bsky.social !

When their preprint came out, it was overshadowed by Regev's paper. I found it disconcerting: space is the key near-term cost and Regev was paying space while this paper was saving space, but then Quanta and Scott Aaronson mentioned Regev but not Chevignard+. Glad they're getting recognition now.

Chevignard's QIP2025 talk on reducing the space cost of quantum factoring: www.youtube.com/watch?v=R3yM... And her co-author Schrottenloher's talk at the Simons Summer Cluster on Quantum Computing: www.youtube.com/watch?v=0pnX...

Gilles Dowek, informaticien engagé et vulgarisateur, est mort

"Awesome Quantum Computing Experiments: Benchmarking Experimental Progress Towards Fault-Tolerant Quantum Computation" arxiv.org/abs/2507.03678 A comprehensive database of notable quantum computing experiments, with emphasis on quantum error correction implementations: github.com/francois-mar...

Les PPP, c'est l'avenir de la recherche de qualité

After all these reports of authors adding language instructions for LLM reviews in their papers I wanted to check this myself and I downloaded the .tex source from one of these papers. Here is an example. (I will not share the identity of the paper)

Ils sont en train de bannir CALVIN & HOBBES du Tennessee 😭

RIP Ray Laflamme, gone too soon. Ray was a stellar scientist, the founding director of ⁦‪the IQC‬⁩ and ⁦‪of CIFAR's‬⁩ Quantum Information program, but more importantly a warm & generous human who built community and helped many (particularly junior researchers). May his memory be a blessing.

Great work by Yiyi Cai that improved the analysis of robustness for the local codes used in quantum Tanner codes. (To be fair, the bounds remain quite pessimistic if one wishes good quantum LDPC codes with linear distance.) thesis.library.caltech.edu/17412/

In a world where more people obsess about their work being inherently meaningful, I hope that you see your job relatively close to the left side of the chart...

"Famously, when published in the journal Physical Review Letters, the copy editor mistook the dim spot (at 347 nm) on the photographic paper as a speck of dirt and removed it from the publication." -- 1st experiment of second harmonic generation en.wikipedia.org/wiki/Second-...

This is a very strong reason we, in quantum information, should try to submit most / if not all of our manuscripts to Quantum Journal. At least the community has some say over the process and authors are in charge of formatting their own manuscripts. Paid journals cannot be trusted.

Academia in 2025: For weeks I’ve been working through botched copy-edits of my monograph, outsourced by the publisher to a company I’d never heard of, until it finally dawned on me the terrible job might be AI. A quick search confirmed the company recently launched new AI software, which now means..

something strange about fault-tolerant quantum computation: we want each logical gate to have an extremely small error proba (between 1e-15 and 1e-12 for Shor's algorithm), and yet, nowhere during the computation is the true quantum state of the computation anywhere close to the ideal one! (1/2)

#newpaper Bosonic codes have a huge potential to reduce the cost of quantum fault tolerance, and many codes look like serious contenders: dual-rail qubit, cat qubit, GKP. But the Fock space is huge, esp. if you consider multimode encodings, and there are many great codes waiting to be found (1/4)

This! I like to say, "Let p|A denote distribution p conditioned on event A. Imagine a world where the laws of probability are the same, except (p|A)|B need not equal (p|B)|A. Except you don't have to imagine, because it's literally our world! Now explore probabilistic algorithms in this world."

Bonus: here's an animation I generated showing how the sausage was made. Each frame is one commit from the paper repo.

Interesting: there will be a "quantum duel" (a debate) about the possibility of quantum computing between Matthias Christandl and Gil Kalai, on May 20. Livestream here: www.learned.cz/en/activitie...

High-performance local automaton decoder for defect matching in 1D, happy to share that our new work in with Anthony Leverrier, Mazyar Mirrahimi and @christophe.vuillot.info is now available on the arXiv ! 👀 (1/6)

There is now an official announcement: The TIB has archived the current status of the arXiv: blog.tib.eu/2025/05/14/p...

looks like a fun job!

Accepted papers at QEC 2025! qec25.yalepages.org/assets/image...

"Most topologists write S^n (instead of S_n) for the sphere of dimension n, in case they forgot that 'n' referred to the dimension." -- J.P. Serre (who prefers to write S_n because ^n is reserved for powers) from the excellent lectures here (in French) www.youtube.com/watch?v=J1g1...

Live committee hearing on How the National Quantum Initiative Shapes US Quantum Technology Leadership, including representatives from Google, Microsoft and PsiQuantum www.youtube.com/watch?v=TH2d...

Open position: we have an excited opening for a 3-year contract (including a very nice welcome package to start building a small team) in our group at Inria Paris. If you want to work on quantum LDPC codes and fault tolerance, please consider applying. (1/2)

I have a positive update regarding this matter: The German National Library of Science and Technology in Hannover (TIB, www.tib.eu) confirmed that they will download and archive the entire arxiv.org as a safety measure.

is there a standard name for the representation of U(n) on the n-mode Fock space that associate to U \in U(n) the unitary {a_i} --> {\sum_j U_{i,j} a_j} ? "metaplectic representation"?

OK #quantum bluesky, I'm making a reading list. Goal: get to the state of the art in Fault-Tolerant Quantum Computing as quickly as possible. I'm using Dan Gottesman's "Surviving..." for the basics. What *one* other paper would you recommend? #quantumcomputing #qec

qubit counts vs 2-qubit gate fidelity in the roadmaps of various quantum computing companies

TIL about the risks of developing "mirror life" and a call for stopping working towards that goal. h/t @michaelnielsen.bsky.social www.science.org/doi/full/10....

Lots of interesting figures on the current SOTA of quantum computing in the Quantum Index Report by MIT: www.yumpu.com/en/document/...