Alice & Bob

It’s not just about qubit count, but how much each qubit counts. ⚛️✨ Some say we’ll need a million qubits to make quantum truly useful. That’s because in most systems only a tiny fraction of the qubits actually compute. The vast majority exist purely to correct errors. ⚙️ At Alice & Bob, we started with a different angle, choosing the cat qubit that’s naturally resistant to certain errors, enabling much simpler error correction codes and slashing this redundancy dramatically. 🐈⬛🚀 In a recent chat with Stephen Ibaraki, Théau Peronnin talks about how hardware efficiency, and not just scale, will be key for practical, fault-tolerant quantum computing. 💡 In the long run, a quantum computer needs to be a tool, not a project. The goal isn’t to build the biggest quantum computer with the most possible qubits, but to build the one that makes the most sense to use in the real world: economical in energy, space, and cost. 🌍⚡️ This conversation dives into various topics: if you’re curious about Alice & Bob's beginnings, how cat qubits work, and fresh perspectives on quantum, this chat will be worth a watch! Podcast link in the comments. #QuantumComputing #ErrorCorrection #DeepTech #HardwareEfficiency

The cats are getting out of the lab and into SLURM! 🐈⬛🚀 We’ve teamed up with the STFC Hartree Centre to plug our cat qubits into the world’s main HPC workflow tool, SLURM. ⚙ If you use a supercomputer, you’ll know SLURM. It runs on over 60% of the world’s supercomputers, slotting tasks onto the right CPUs, GPUs, and even QPUs. 🧠 This collaboration lays the bricks to bring quantum compute into those same workflows. ⚡💻 For the first time, cat-qubit processors will be able to operate inside an HPC environment as just another compute resource, a necessary step in getting quantum ready for practical, real-world use. 🔬🚀 Today only a handful of quantum hardware teams worldwide are working to integrate with SLURM, and our cats are proudly one of them. The early fault-tolerant era will unlock applications that classical computers alone could never do. But since these applications will be executed as a choir rather than a solo, we need true hybrid systems, where quantum and classical compute work side by side, each playing to their strengths. ⚛️🤝💻 Big thanks to the Hartree Centre for working with us on this step toward seamless quantum–classical integration! 🙌 #QuantumComputing #HPC #SLURM #CatQubits

Why can’t you buy a useful quantum computer yet? 🤔 Every quantum computer you buy today is NISQ, noisy, mid-sized machines. But almost every roadmap, press release, and funding deck talks about FTQC. And they’re right to, because while NISQ machines are great for testing, learning, and proof-of-concept experiments, FTQC (Fault-Tolerant Quantum Computing) is the only proven path to quantum value. 🚀⚛️ As Eisert and Preskill remind us in a recent article, fault-tolerance is the only way to make quantum computing practical and useful. So, why aren’t we there yet? Because FTQC isn’t just NISQ 2.0. It’s a whole different animal, built on different logic, different gates, different… everything. ⚙️ As always, a simplified rundown, but here’s the gist 👇 🔹 Brand new algorithms 🧠 You can’t just take a NISQ algorithm and add more qubits. NISQ algorithms like VQE approximate results using short circuits that can tolerate noise, whereas FTQC can run far more powerful algorithms like QPE that only work with full error correction. 🔹 A smaller set of building blocks 🧱 In NISQ, gates are implemented continuously, you can dial them how you want to adjust your qubits exactly. In FTQC, you only have a fixed set of gates, so building an operation becomes a clever game of combining a few pieces in the most efficient way possible. More tricky, but more powerful. 🔹Run-time is what matters ⏱️ In NISQ, you squeeze your circuit with less qubits, shorter circuits, and limited connectivity to “outrun” noise. In FTQC, you correct errors as you go along, which gives you unlimited circuit depth and full connectivity, but at the cost of huge resource overhead. The goal becomes trimming run-time, a careful trade-off between time and fidelity, to make it practical for real world applications. 🔹 Error correction is everything 🛡️ Making FTQC work is a whole new craft. Hardware, gates, and error correction all have to be designed together, and that requires developers to learn new tricks, from fault-tolerant compilation to quantum error correction. FTQC means a new kind of machine, and a completely different engineering challenge. That’s why designing for FTQC is hard, long, but absolutely worth it. At Alice & Bob we had the rare chance to choose fault-tolerance from day one, five years ago, knowing it meant a fundamentally different paradigm, with fundamentally different building blocks. Our cat qubits suppress quantum errors at the source. That’s our path to a first fully-fledged quantum computer that is powerful, reliable, and fault-tolerant by 2030. ⚛️🐈⬛⚡ #QuantumComputing #ErrorCorrection #FTQC

Classical computers solve most problems faster. But for certain classes of very complex problems, only quantum will make them possible. ⚛️ Right now, the most powerful classical supercomputers can exactly simulate about 60 qubits. 🖥️ A few exceptions exist for some edge cases, but quantum simulations will be, by and large, a playground for quantum computers. 🔮 We explored all this and more with Alice & Bob's Juliette Peyronnet and Bob Sorensen from Hyperion Research, hosted by insideHPC’s Doug Black. Here’s a taste of what we dug into: 🔷 The idea of “quantum heuristics”, meaning how user experimentation on real devices may lead to creative new methods and shortcuts, just like we saw in the early days of classical computing. 🔷 How quantum is set to impact up to 50% of scientific computing workloads, according to national labs’ own studies. 🔷 Why high performance computing teams need to start designing quantum-classical applications now alongside quantum players to stay competitive into the quantum era. It’s a great entry point to key ideas in our report, also with Hyperion Research, on the future of quantum and high-performance computing. ⚛️🖥️ 🎧 Watch the full conversation: https://lnkd.in/eZfZdFXe 📝 Read our report: 👉 https://lnkd.in/eFDHZGnG #QuantumComputing #HPC #FutureOfComputing

We’re back in the kitchen with NVIDIA 🔥, but this time it's in their kitchen. We’re proud to support the launch of NVQLink, announced yesterday by Jensen Huang on stage at #NVIDIAGTC Washington. NVQLink tackles a big challenge in quantum computing: integrating the best of classical with the cutting edge of quantum error correction. ⚡ This is all about perfect orchestration, pun intended, classical GPUs and quantum processors working hand-in-hand, each playing to their strengths in a single seamless workflow. 🤝 That’s what NVQLink is set to achieve: 1️⃣ Live calibration – qubits drift, all the time, requiring constant fine-tuning. GPUs step in to process the calibration data in real time, keeping qubits reliable and measurements accurate. 2️⃣ Error decoding – quantum systems produce errors constantly. GPUs are perfectly suited to interpret these incoming errors, so QPUs can correct them. 3️⃣ Logical orchestration – fault-tolerant computing depends on the precise timing of calibrations, measurements, and corrections. Classical GPUs choreograph these operations, ensuring the whole system works together as it should. You might remember we are already cooking with NVIDIA to speed up QPU simulations with our Dynamiqs and CUDA-Q integration. 🚀 Now, with NVQLink, we’re taking classical-quantum integration even further: building the workflows that will turn qubits from lab experiments into the foundations of real-world, fault-tolerant quantum computers. ⚛️🖥️ Stay tuned for more! #QuantumComputing #NVIDIA #HybridComputing

Is FTQC dead? 🤔 No, FASQ is the next step in FTQC. A new landmark paper by field giants Jens Eisert and John Preskill, creator of the term NISQ, hits us with a new acronym: FASQ, Fault-tolerant Application Scale Quantum Computing. FASQ marks the moment when quantum computers become capable of running useful applications for the world. The paper outlines 4 steps for a quantum computers to enter the FASQ era. 🚀 This is an Alice & Bob digest and, as usual, we simplified things a lot, but in a nutshell: 1️⃣ Today’s quantum computers can run a set of operations and at best give you an ex-post “summary” of the errors they made. Tomorrow’s FASQs need to detect and correct errors automatically and as they happen to never stop an algorithm and always give the right result. ⚙ 2️⃣ Today’s quantum computers can run small error-corrected circuits (hundreds of qubits at best) and still settle for pretty unreliable results, but tomorrow’s FASQ will have to reach orders of magnitude lower error rates and hundreds of thousands of physical qubits. 📈 3️⃣ As quantum computers get more complex, we need to have verifiable algorithms, meaning those we can cross-check to confirm that they did what they were supposed to. ✅ 4️⃣ For now, quantum computers remain experimental tools. The most useful thing they do right now is help us build their next iteration. A lot of fun for us, but not necessarily relevant for the rest of the world. To reach FASQ, we need to achieve credible quantum advantage, meaning a result that is useful and beyond what any classical computer can do. 🎯 The authors also talk about hardware-efficient approaches, mentioning cat qubits. 🐈⬛ As they put it: “It might pay off to make the physical qubits more complicated if (this) makes it easier to realize logical qubits...” Cat qubits ”strongly suppress bit-flip error rates…potentially reducing the overhead cost of error correction.” At Alice & Bob, we are aiming to create the best logical qubits by building our entire architecture on cat qubits. ⚡ We strongly agree with the paper's outlook. Early FTQC is a necessary step, but it's not the endgame on the journey of making quantum computers fault-tolerant and application-ready. 🖥️⚛️ Quantum is evolving at breakneck speed, and with FASQ it’s going to get a whole lot more exciting. 🔥 #QuantumComputing #FTQC #FASQ #CatQubits

Qubits are only as good as the materials we build them from. That’s why we’re teaming up with PLASSYS BESTEK, specialists in thin film deposition tech, to take our quantum chip fabrication capabilities to the next level. 🚀🛠️ As part of the ULTRACAT project 🐈⬛, supported by the French Government’s Agence de l'innovation de défense, PLASSYS-BESTEK’s chip fabrication equipment SQUID-6 UHV will soon be installed in our upcoming €50M lab in Paris. ⚛️ SQUID-6 UHV is a new state-of-the-art deposition system, capable of processing multiple wafers, the shiny discs of sapphire we build our QPUs on, in series. This unique tool was developed and built by PLASSYS-BESTEK for Alice & Bob in a world-first. The SQUID-6 core creates ultra-high vacuum conditions. Around this core independent chambers host tools that can perform different nanofabrication processes without contaminating the others. This marvel of engineering allows us to produce more QPUs, at a higher quality, faster. 💎⚡ What we care about at Alice & Bob is producing high-fidelity qubits at scale. To do that we need the best fabrication technologies to test our chip designs at breakneck speed and with minimal variability, and this is what the ULTRACAT project and this collaboration with PLASSYS-BESTEK is all about. On another note, we can’t thank the French Government enough, and specifically the Agence de l'innovation de défense and DGA - Direction générale de l'armement for their continuous commitment in supporting the whole quantum value chain, a testament to how building a sovereign technological future happens through action. 🇫🇷 #QuantumComputing #QuantumHardware #QuantumLab #Physics

Quantum still has to prove itself. Many in the quantum world (including us!) think we will see useful applications of quantum computing by 2030. But experts in classical computing are not so easily convinced. 🤔 Last week, Laurent Prost and Rémi de La Vieuville joined the HPC User Forum, where Rémi took to the stage to explore quantum for HPC, before more of the Alice & Bob team continued the exchange at our after-event. We had many fruitful discussions where our enthusiasm met some grounded skepticism. With current quantum computers being capable of so little, and with investment in classical computing capabilities reaching record highs, can quantum really change the game in just five short years? 🕰️ Of course, the revolution will not happen overnight, and it will not affect every field. But with quantum error correction solving the shortcomings of current quantum computers, we project about half of today’s HPC workloads could benefit from quantum computing in the early 2030s. 📊 Getting there means quantum and HPC working side-by-side, where quantum expertize meets HPC know-how. 🤝 The future lies in hybrid quantum-classical workflows — and these workflows will need to be co-designed. Quantum computers also need to fit into existing HPC environments, adapting to decades of established ways of working. ⚙ Hitting technological milestones on time is just part of the equation. Unlocking the full potential of early quantum computing requires close collaboration as quantum technology evolves. ⚛️ It was an enriching exchange, a chance to understand each other’s challenges and explore how our worlds can come together — to the tune of some live jazz. 🎷 Here’s to the next one. 📝 Dive deeper in our report: 👉 https://lnkd.in/eFDHZGnG #HPCUserForum #HPC #QuantumComputing #FutureOfComputing Photo credits: Anna Ellouk

🔥 Alice & Bob featured in the Top 20 Startups in France by LinkedIn! 🇫🇷 Five years ago, we were a handful of PhD students obsessed with physics and passionate about cats 🐈⬛. Today we’re 150 people building what could become the first useful quantum computer by 2030. ⚛️🖥️ The Top 20 Startups list is based on community engagement, so we feel especially proud to make it on there. 🙌 And we’re just getting started. We’re hiring 100 new teammates by mid-2026. If you’ve ever wondered about quantum, there’s never been a better time to jump in. 👇 🚀 Join us: alice-bob.com/join-us 📰 Read the news: https://lnkd.in/gT9n3Tp3 #LinkedInTopStartups #QuantumComputing #Physics #Hiring

Cecile M. Perrault of Alice & Bob has made Sifted’s 100 Women in Tech in Europe 2025! 🌟 This first edition, curated with STATION F and SISTAFUND, recognizes female tech leaders in Europe — from founders to policymakers to journalists and corporate leaders — who are making a real impact and deserve to be celebrated. 🚀 As our Head of Innovation and Partnerships, Cécile is driving quantum tech from the lab to the real world. This year she was also elected Vice President of the European Quantum Industry Consortium (QuIC), helping to strengthen European competitiveness on the global stage. ⚛️ In the office, Cécile is always that one spotting what’s next, and somehow already making it happen! ✨ It’s great to see quantum spotlighted, and we’re proud to see Cécile celebrated among other inspiring leaders. Big congrats to Cécile! 👏 See the full list: https://lnkd.in/dbKmZCGF #WomenInTech #Leadership #Policy #TechDiplomacy #Europe #France