Alice & Bob may be pursuing the most technically ambitious approach to quantum computing in Europe. Founded in 2020 in Paris, the company develops quantum computers based on cat qubits — a novel superconducting circuit design that inherently suppresses one of the two dominant error types in quantum computing. If the cat qubit architecture delivers on its theoretical promise, Alice & Bob could build fault-tolerant quantum computers requiring dramatically fewer physical qubits than competing approaches, potentially accelerating the timeline to practical quantum advantage by years. That is a significant “if” — but France 2030’s quantum strategy deliberately funds this kind of high-risk, high-reward technical bet alongside more conservative approaches.
The Cat Qubit Concept: Error Suppression by Design
To understand Alice & Bob’s technical position, it is necessary to understand the fundamental problem of quantum error correction. Quantum bits (qubits) are fragile: they interact with their environment in ways that corrupt the quantum information they encode. These errors come in two types: bit flips (a qubit in state |0⟩ spontaneously flips to |1⟩ or vice versa) and phase flips (a qubit in superposition state picks up an unwanted phase shift).
Most quantum error correction approaches treat both error types symmetrically, using codes like the surface code to detect and correct both types simultaneously. The overhead is severe: protecting one logical qubit from errors requires hundreds to thousands of physical qubits in current state-of-the-art superconducting systems.
Cat qubits exploit a physical asymmetry. A cat qubit is a superconducting circuit operating in a two-photon driven-dissipative regime — a regime first explored theoretically by Michel Mirrahimi at INRIA and experimentally by Zaki Leghtas at ENS Paris (both of whom are scientific co-founders of Alice & Bob). In this regime, the qubit’s quantum state is protected against bit flips exponentially as the photon number increases. Bit flip rates can be suppressed to essentially zero; phase flip rates remain present but are manageable.
This asymmetry is powerful. A quantum error correction code designed for a noise model where bit flips are exponentially rare and only phase flips need to be corrected requires roughly 10× fewer physical qubits than a symmetric code designed for equal bit-flip and phase-flip rates. If Alice & Bob’s cat qubits perform as theoretically predicted, a fault-tolerant logical qubit might require only 100 physical cat qubits rather than 1,000 conventional superconducting qubits.
Founders and Scientific Lineage
Alice & Bob was co-founded in 2020 by Théau Peronnin and Raphaël Lescanne, both PhD graduates from ENS Paris working on the experimental implementation of cat qubits.
Peronnin completed his PhD at ENS Paris on the experimental realization of cat qubit states, directly demonstrating the bit-flip suppression that is the company’s technical foundation. He serves as CEO, bringing both deep technical expertise and the entrepreneurial orientation needed to build a commercial quantum company.
Lescanne’s PhD work at ENS Paris demonstrated the first experimental cat qubit with suppressed bit flips — the key result that validated the approach commercially. He serves as CTO.
The scientific co-founders are Mirrahimi (INRIA, theoretical architect of the cat qubit approach) and Leghtas (ENS Paris, experimental pioneer). Both maintain active research roles while advising the company, ensuring Alice & Bob stays at the frontier of cat qubit physics.
The CEA (Commissariat à l’Énergie Atomique et aux Énergies Alternatives) is a key institutional partner, providing fabrication access through CEA-Grenoble’s quantum device laboratory and contributing applied physics expertise.
Funding and Development Stage
Alice & Bob raised a €30 million Series A in 2022, led by Supernova Invest with participation from Bpifrance (through France 2030 quantum funding channels) and several other investors. This follows a €3 million pre-seed in 2021.
Total raised: approximately €35 million. This positions Alice & Bob as a well-funded quantum hardware startup but significantly smaller than Pasqal (€107 million raised). The difference reflects stage: Pasqal is deploying commercial systems; Alice & Bob is still demonstrating technical milestones needed to validate the cat qubit pathway to fault-tolerant computing.
France 2030’s PEPR Quantique program provides Alice & Bob with research grants separate from equity investment, funding specific hardware development milestones and enabling the company to maintain connections with academic research teams at ENS Paris and INRIA.
Technical Roadmap
Alice & Bob has published a detailed technical roadmap with specific milestones:
2023: Demonstrate a cat qubit with bit-flip suppression greater than 1,000× relative to an unprotected qubit at the same photon number. This milestone validates the fundamental premise of the cat qubit approach at a practically useful protection level.
2024-2025: Demonstrate a logical qubit encoded in cat qubits that outperforms its constituent physical qubits — the first demonstration of quantum error correction improving rather than worsening performance. This is the most important near-term milestone and has been the grail of quantum error correction experimentalists for two decades.
2026-2027: Operate a multi-logical-qubit system capable of executing short quantum algorithms with below-threshold error rates. This is the entry point to fault-tolerant quantum computing.
2030+: Commercial fault-tolerant quantum computer for industrial simulation and cryptography applications.
The roadmap is aggressive. IBM’s own path to fault-tolerant computing, using conventional surface codes on superconducting qubits, targets similar timelines with a very different physical approach. The question is which architecture arrives first at the fault-tolerant threshold — and whether the cat qubit efficiency advantage translates to real systems as well as theoretical analyses suggest.
Partnership with CEA and INRIA
CEA-Grenoble provides Alice & Bob with access to state-of-the-art superconducting quantum device fabrication — the same facility that fabricates chips for France’s nuclear instrumentation and radiation detection programs, adapted for quantum device manufacturing. This partnership gives Alice & Bob access to nanofabrication capabilities that would be prohibitively expensive to build independently, and represents France 2030’s strategy of leveraging existing national research infrastructure for quantum startups.
INRIA’s involvement through Michel Mirrahimi provides ongoing theoretical support, particularly on the quantum error correction codes optimal for cat qubit noise models. INRIA has published extensively on “cat qubit codes” — error correcting codes specifically designed for the asymmetric noise model of cat qubits — ensuring Alice & Bob has access to the best available theoretical tools for its hardware platform.
Competitive Landscape
Alice & Bob occupies a unique niche: it is the only company globally pursuing the bosonic cat qubit approach at commercial scale. IBM, Google, and Rigetti all use conventional transmon qubits with symmetric noise models. QuEra and Pasqal use neutral atoms. PsiQuantum uses photonics. The closest competitor is Amazon Web Services, which has a significant internal research program (AWS Center for Quantum Computing) that has explored bosonic qubit approaches, though without the specific cat qubit architecture.
Yale University has significant cat qubit research (the Schoelkopf lab), but as an academic rather than commercial enterprise. Alice & Bob’s tight coupling to ENS Paris and INRIA — the institutions that invented the cat qubit — provides a first-mover advantage that is difficult to replicate quickly.
Strategic Role in France’s Quantum Portfolio
Alice & Bob represents France 2030’s highest-risk, potentially highest-reward quantum bet. Within France’s diversified quantum portfolio (neutral atoms at Pasqal, photonics at Quandela, superconducting at Alice & Bob, carbon nanotubes at C12), Alice & Bob occupies the fault-tolerant computing niche — the approach most directly targeting the large-scale general-purpose quantum computer that can tackle cryptography, drug discovery, and materials science at scale.
If the cat qubit delivers on its theoretical promise, Alice & Bob has the potential to be the company that achieves genuine fault-tolerant quantum computing first — ahead of IBM, Google, and Microsoft, with their multi-billion dollar programs. That outcome would be transformative not just for Alice & Bob but for France’s quantum and strategic autonomy ambitions.
The probability of achieving fault-tolerant advantage before the US giants is not high. But France 2030’s strategy correctly recognizes that maintaining a credible position at the frontier — even a minority probability position — is more valuable than conceding the field and depending entirely on US quantum cloud for the next generation of computational infrastructure.