C12 Quantum Electronics: Next-Gen Carbon Nanotube Processors For European Sovereign Computing

C12 Quantum Electronics is a deep-tech start-up spun off in 2020 from the École Normale Supérieure (Paris) to develop next-generation quantum processors based on carbon nanotube spin qubits [1] . Headquartered in Paris, France [2] , the privately held firm (venture-backed, with investors such as Bpifrance Digital Ventures and the EIC Fund [3] ) operates solely in France. Its official website is c12qe.com , and it communicates via press releases and technical articles.

C12’s governance is led by founders Matthieu and Pierre Desjardins (scientists) with oversight from a board of investors; there is no public record of any sovereign fund or joint-venture ownership. The company has no known subsidiaries or extensive overseas offices; its activities are concentrated at its Paris labs and nanofabrication facilities. While C12 partners closely with French and European research institutions (CNRS, CEA-Leti) and industry (Thales, Air Liquide), there is no indication of direct classified program participation or clearance levels publicly disclosed.

C12’s core mission is to design and build large-scale, fault-tolerant quantum computers using carbon nanotube qubits [4] . It positions itself as a specialized technology provider within the European defence-industrial base, not as a full systems integrator. The company follows a vertically integrated R&D model: it develops proprietary hardware (in-house cleanroom fab and dilution refrigerators) and software (the “Callisto” emulator) while leveraging academic and industrial partnerships [5] [6] .

Early on it invested in its own Paris nanofab (fabricating its qubits on silicon) to control its supply chain [5] . C12 primarily targets national security and industry sectors, acting as a supplier of advanced quantum hardware and algorithms (for example, with ongoing use-case studies in aerospace and cryptography), rather than a prime contractor. Its strategy is aligned with European autonomy initiatives: by developing home-grown quantum chips, C12 aims to contribute to Europe’s sovereign capabilities in computing and encryption.