Uploaded March 2026 | Updated September 2026, 3 weeks ago
The story starts at the École Normale Supérieure. Twin brothers Pierre and Matthieu Desjardins trained together in quantum physics before taking separate paths—one deeper into science, the other into business. Years later, a shared insight brought them back together: unlike superconducting circuits or trapped ions, carbon-nanotube spin qubits offered a radically cleaner and more controllable foundation for quantum computing. To pursue this alternative, they founded C12.
At C12, the mission is to drive one of the defining technological breakthroughs of the century by reinventing how quantum computers are built. Instead of competing in the race to brute-force scaling—adding more qubits and heavier layers of error correction—the focus is on a different path. Ultra-pure carbon nanotubes create low-disorder qubit environments where errors are minimized at the source, enabling compact, high-density systems that are scalable, affordable, and suited to real industrial use.
The work begins at the smallest possible scale at the only quantum fabrication facility in central Paris. Qubits are crafted from ultra-pure carbon nanotubes grown and perfected in the Paris Quantum Fab, where individual electrons can be manipulated with extraordinary precision. An end-to-end scientific workflow—growth, selection, characterization, nano-assembly, and device readiness—is fully controlled in-house. This tight feedback loop accelerates iteration and supports a clear roadmap, from multi-qubit demonstrations to 3D integration and a pragmatic error-correction strategy shaped by hardware reality.
The resulting architecture centers on a compact, single-cryostat system with efficient connectivity, quantum bus design, and optimized cryogenics, built to integrate naturally into HPC environments and datacenters. Callisto, a quantum emulator, allows workloads to be explored and refined long before large-scale hardware is deployed.
Industry collaboration is essential to turning quantum capability into impact. Partnerships such as with Thales target aerospace, defense, sensing, and optimization—use cases including tracking, sensor fusion, and high-stakes decision-making. Behind the technology is a team defined by collaboration, craftsmanship, and scientific curiosity, working to place Paris at the center of a historic technological shift.
c12qe.com
The story starts at the École Normale Supérieure. Twin brothers Pierre and Matthieu Desjardins trained together in quantum physics before taking separate paths—one deeper into science, the other into business. Years later, a shared insight brought them back together: unlike superconducting circuits or trapped ions, carbon-nanotube spin qubits offered a radically cleaner and more controllable foundation for quantum computing. To pursue this alternative, they founded C12.
At C12, the mission is to drive one of the defining technological breakthroughs of the century by reinventing how quantum computers are built. Instead of competing in the race to brute-force scaling—adding more qubits and heavier layers of error correction—the focus is on a different path. Ultra-pure carbon nanotubes create low-disorder qubit environments where errors are minimized at the source, enabling compact, high-density systems that are scalable, affordable, and suited to real industrial use.
The work begins at the smallest possible scale at the only quantum fabrication facility in central Paris. Qubits are crafted from ultra-pure carbon nanotubes grown and perfected in the Paris Quantum Fab, where individual electrons can be manipulated with extraordinary precision. An end-to-end scientific workflow—growth, selection, characterization, nano-assembly, and device readiness—is fully controlled in-house. This tight feedback loop accelerates iteration and supports a clear roadmap, from multi-qubit demonstrations to 3D integration and a pragmatic error-correction strategy shaped by hardware reality.
The resulting architecture centers on a compact, single-cryostat system with efficient connectivity, quantum bus design, and optimized cryogenics, built to integrate naturally into HPC environments and datacenters. Callisto, a quantum emulator, allows workloads to be explored and refined long before large-scale hardware is deployed.
Industry collaboration is essential to turning quantum capability into impact. Partnerships such as with Thales target aerospace, defense, sensing, and optimization—use cases including tracking, sensor fusion, and high-stakes decision-making. Behind the technology is a team defined by collaboration, craftsmanship, and scientific curiosity, working to place Paris at the center of a historic technological shift.
c12qe.com
