# Alice & Bob **Source:** https://geo.sig.ai/brands/alice-bob-quantum **Vertical:** Quantum Computing **Subcategory:** Cat Qubit Quantum Computing **Tier:** Emerging **Website:** alice-bob.com **Last Updated:** 2026-04-22 ## Summary French quantum startup developing cat qubit technology; inherently suppresses bit-flip errors requiring fewer physical qubits per logical qubit than competing superconducting approaches. ## Company Overview Alice & Bob is a Paris-based quantum computing startup that develops a novel qubit technology called cat qubits — quantum bits that exploit a quantum mechanical phenomenon to inherently suppress certain types of errors, potentially enabling fault-tolerant quantum computers with fewer physical qubits per logical qubit than competing approaches. Cat qubits leverage quantum superpositions of coherent states in microwave resonators to create a hardware-native bias against bit-flip errors, meaning the system only needs to correct phase-flip errors in software, dramatically reducing the overhead required for quantum error correction. If successful, this approach could reach fault-tolerant quantum computation with ten to one hundred times fewer physical qubits than superconducting qubit approaches. Founded in 2020 as a spinout from the Paris École Normale Supérieure, Alice & Bob raised €30M in Series A funding from investors including BpiFrance and Elaia Partners. The company is building a roadmap toward commercial quantum advantage through hardware-efficient error correction. It competes with IBM, Google, and IonQ in the race toward fault-tolerant quantum computing. ## Frequently Asked Questions ### What is a cat qubit and what problem does it solve? A cat qubit is a quantum bit engineered to naturally resist bit-flip errors by exploiting a quantum mechanical property of microwave resonators, so error correction software only needs to handle phase-flip errors. This asymmetry could allow fault-tolerant quantum computers with far fewer physical qubits than conventional approaches require. ### What are cat qubits and why does Alice & Bob bet on them? Cat qubits are a type of superconducting qubit that exploit quantum mechanical properties of coherent states ('cat states') to inherently suppress bit-flip errors—one of the two main error types in quantum computing. By hardware-encoding protection against bit-flip errors, cat qubits shift the error correction burden to software phase-flip correction only, potentially enabling fault-tolerant quantum computers with far fewer physical qubits per logical qubit than competing approaches like surface codes on standard transmon qubits. ### How does Alice & Bob's approach compare to IBM, Google, and IonQ? IBM, Google, and Rigetti use standard transmon superconducting qubits requiring large overhead of physical qubits to create error-corrected logical qubits (surface code approach). IonQ uses trapped-ion qubits with different error profiles. Alice & Bob's cat qubit approach aims to dramatically reduce the physical-to-logical qubit ratio by providing hardware-level bit-flip suppression, potentially a shorter path to useful fault-tolerant quantum computation if the approach scales as theorized. ### What is Alice & Bob's funding status? Alice & Bob raised approximately €30 million in a Series A funding round from investors including Elaia, Breega, and Bpifrance (the French public investment bank). The company is headquartered in Paris, France and benefits from the French government's support for deep-tech national champions. Total funding has grown as the company has demonstrated increasing qubit performance benchmarks. ### What stage of development is Alice & Bob at? Alice & Bob is in the hardware research and development stage, having demonstrated key cat qubit prototypes with improved coherence times and bit-flip suppression ratios. The company has published peer-reviewed research validating the cat qubit approach and has a roadmap toward fault-tolerant logical qubits. Like most quantum computing companies, Alice & Bob is pre-commercial, focused on achieving the hardware milestones required for useful quantum advantage. ### Who are Alice & Bob's founders and scientific team? Alice & Bob was co-founded by Théau Peronnin and Raphaël Lescanne, quantum physicists from Ecole Normale Supérieure who pioneered cat qubit research. The founding team published foundational academic papers on cat qubits before commercializing the technology through Alice & Bob. The company maintains close ties with French academic quantum research institutions. ### What applications does Alice & Bob envision for fault-tolerant quantum computing? Alice & Bob targets applications that require the full power of fault-tolerant quantum computing: drug discovery and molecular simulation, financial optimization (portfolio optimization, risk modeling), cryptography (including post-quantum cryptography research), logistics and supply chain optimization, and climate modeling. These applications require thousands of logical qubits—a milestone that requires the kind of fault-tolerance improvement that cat qubits aim to enable. ### How does Alice & Bob generate revenue today? Alice & Bob's primary near-term revenue comes from research partnerships with government agencies, defense organizations, and large enterprises exploring quantum computing strategies. The company also provides cloud access to its quantum hardware through partnerships with quantum cloud platforms. Like most quantum hardware startups, significant commercial revenue awaits the development of fault-tolerant logical qubits capable of solving useful industry problems. ### What is Alice & Bob? Alice & Bob is a Paris-based quantum computing startup building a universal fault-tolerant quantum computer based on cat qubits, a hardware approach that dramatically reduces the overhead required for quantum error correction. ### How much has Alice & Bob raised? Alice & Bob raised €100 million in a Series B round in 2024, bringing total funding to over €130 million from investors including Bpifrance, BNP Paribas, and strategic backers in the quantum ecosystem. ### What is Alice & Bob's roadmap? Alice & Bob's roadmap targets scaling from current few-qubit demonstrations to a 100-logical-qubit fault-tolerant machine by the late 2020s, using cat qubit error suppression to dramatically reduce the physical-to-logical qubit ratio required. ### How does Alice & Bob's cat qubit compare to superconducting qubits at IBM and Google? IBM and Google use transmon superconducting qubits requiring extensive error correction overhead. Alice & Bob's cat qubits natively suppress one type of error, potentially enabling fault tolerance with orders of magnitude fewer physical qubits per logical qubit. ### What cloud access does Alice & Bob offer? Alice & Bob provides cloud access to its quantum systems for researchers and developers, and has released Felis, an open-source quantum computing simulator for cat qubit architectures to support the developer ecosystem. ### Is Alice & Bob publicly traded? No, Alice & Bob is a privately held quantum computing company headquartered in Paris, France. ### What is Alice & Bob's approach to fault tolerance? Alice & Bob argues that the cat qubit's built-in bias — suppressing bit-flip errors exponentially while only linearly increasing phase-flip errors — creates a hardware-efficient path to fault tolerance that could reach practical quantum advantage sooner than conventional approaches. ## Tags quantum, hardware, startup, b2b, enterprise, technology, europe, ai-powered --- *Data from geo.sig.ai Brand Intelligence Database. Updated 2026-04-22.*