Alice & Bob

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.