Christophe Vuillot

Just Out of the Lab: A Cat Qubit That Jumps Every Hour - Alice & Bob We show early research suggesting cat qubits can resist to bit-flip errors for multiple hours while keeping quantum control.

We'll definitely try over here at @alice-and-bob.bsky.social ! See for instance alice-bob.com/blog/just-ou...

Con-cat-enated

🍦🐱 & 🍽️ !

Can cat-qubits get away with only ever using (concatenated) classical codes?
@pshanahan62.bsky.social and @diego-ruiz.bsky.social investigate and suggest yes!
#quantum ⚛️ 🧪

Elevator Codes: Concatenation for resource-efficient quantum memory under biased noise Biased-noise qubits, in which one type of error (e.g. $X$- and $Y$-type errors) is significantly suppressed relative to the other (e.g. $Z$-type errors), can significantly reduce the overhead of quant...

New preprint out with @pshanahan62.bsky.social! We introduce a new error-correcting code for biased-noise qubits. Built from the concatenation of two classical codes, it outperforms the surface and XZZX codes when the noise bias exceeds 7x10^4.
arxiv.org/abs/2601.10786

We did some experimental testing of magic state cultivation! arxiv.org/abs/2512.13908

A ~1e-4 end2end infidelity is tricky to measure with tomography, so we checked it vs more cultivation. The full escape stage is too wide for the chip, but we did try ending in the grafted code.

This morning my ChatGPT quota was inexplicably exhausted.

It took a while but I pieced it together. Voice mode somehow got activated when I went to bed.

The bot then engaged in a 10 hour conversation with my snoring dog, answering questions the pup wasn’t asking and praising him for his insight.

New paper out ✨

Fault-tolerant Transformation of Spacetime Codes, a collaboration w/ @vasmer.bsky.social, Austin Daniel & Ilan Tzitrin, which started during my internship @xanaduai.bsky.social

scirate.com/arxiv/2509.0...

Let's now see if I can summarize 101 pages (🙈) in a few tweets (and memes!)

Hi, I am here! Will mostly post about Quantum Foundations/Computing and Quantum Music.

You forgot
Example 0: trivial group

David Smith (mathématicien) — Wikipédia

Ça me rappelle l'histoire de la tuile aperiodique quand même fr.wikipedia.org/wiki/David_S...

Colour Codes Reach Surface Code Performance using Vibe Decoding Two-dimensional quantum colour codes hold significant promise for quantum error correction, offering advantages such as planar connectivity and low overhead logical gates. Despite their theoretical ap...

Color code decoding with some big claim: arxiv.org/abs/2508.15743

I wish they could try to benchmark this decoder against the experimental color code data from arxiv.org/pdf/2412.14256 zenodo.org/records/1423...

We are releasing experimental data so people can try out their decoding algorithms!

\([[8,3,2]]\) Surface code on a cube An [[8,3,2]] twist-defect surface code whose qubits lie on the vertices of a cube. It is obtained by three-coloring the faces of a cube and placing X, Y, and Z stabilizer generators on each pair of fa...

In closing of #qec2025, we have put up our 1000th code -- the [[8,3,2]] surface code on a cube (aka the Landahl plucky code)! It is a non-CSS code different from the smallest interesting color code. Stabilizer generators are X, Y, or Z strings on the faces. errorcorrectionzoo.org/c/cubic_surf...

Unfolded distillation: very low-cost magic state preparation for biased-noise qubits Magic state distillation enables universal fault-tolerant quantum computation by implementing non-Clifford gates via the preparation of high-fidelity magic states. However, it comes at the cost of sub...

Probably the last paper of my PhD! We show that biased-noise qubits can greatly reduce the cost of magic state preparation

With high noise bias, just 53 qubits and ~10 error correction cycles are enough to prepare a magic state with logical error≈1e-7
arxiv.org/abs/2507.12511

Signez la pétition Sauvons le Palais de la découverte

Le Palais de la découverte a besoin de soutient ! C'est un musée des sciences vraiment réussi et pour tous les âges !
👉 chng.it/SzH6WkfXH2
⚛️🧪

So this headline is actually wrong, right? www.nasdaq.com/articles/ins...

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)

🧪⚛️🧮

Is there an official announcement somewhere?

Engineering CSS surgery: a fault-tolerant CNOT for any CSS codes We introduce a framework for implementing logic in CSS-style quantum error correction codes, building on the surgery methods of Cowtan and Burton [CB24]. Our approach offers a systematic methodology f...

So here it is, my first first-author paper is live on the arXiv arxiv.org/abs/2505.01370

Anyone who can spare an invite to the "global economy dump and pump" signal group chat?

Yes, thanks to @arrr.de and the German National Library of Science and Technology in Hannover (TIB, www.tib.eu) :)

bsky.app/profile/arrr...

Someone backed up arxiv.org yet?

Quantum is interesting because it is making a transition from one of culture to another. (Has made?) But we can still fight to keep quantum weird!

In 1h (9am PST or 5pm CET) I will give a talk at the QASAR seminar hosted by @vasmer.bsky.social and @christophe.vuillot.info . I will present our work on implementing 3coupler, walking and iSWAP surface codes!

@alice-and-bob.bsky.social

Diego presenting his work under the expert eye of Craig Gidney

Summary slide of Diego's results

Two talks of Alice&Bob QEC team in parallel this morning:

@diego-ruiz.bsky.social presented his new results on distillation with biased-noise qubits: with bias=30 he already gets 150x reduction!

I talked about implementing rotor codes

So many fun subjects to work on, join our team we are hiring!🐱

I'll be at the @apsphysics.bsky.social March Meeting next week in Anaheim.

I have a talk on Friday about quantum rotor codes, protected superconducting qubits and tiger codes in the advances in quantum error correction session.

Also come talk to me whenever!

The QEC team at Alice & Bob is hiring ! Come work with me on 🐈 cat codes, 🐅 tiger codes, decoding, biased-noise, distillation, LDPC codes, ...
👇
jobs.lever.co/alice-bob/c0...

Enhancing dissipative cat qubit protection by squeezing Dissipative cat-qubits are a promising architecture for quantum processors due to their built-in quantum error correction. By leveraging two-photon stabilization, they achieve an exponentially suppres...

First realization of a dissipatively stabilized squeezed cat qubit (a slight variation that we called a moon cat 🌛 actually), it was super interesting to work on this with experimentalists!
arxiv.org/abs/2502.07892
My two key takeaways ⬇️⬇️