MARCH 16, 2026. Paris, France and Ulm, Germany.
C12, a Paris-based quantum computing company developing a unique carbon nanotube spin-qubit architecture for scalable, universal quantum computing, has announced the adoption of QC Design’s Plaquette software to accelerate the development of its fault tolerant quantum computing architecture. Plaquette is a quantum design-automation platform that enables theory teams to simulate, analyze, and optimize fault-tolerant designs under realistic noise models. This collaboration equips C12 with the tools to benchmark quantum error-correcting codes and refine its unique carbon nanotube architecture as the company scales towards practical fault tolerance.
C12’s approach uses isotopically purified carbon-12 nanotubes to host spin qubits with exceptionally low noise. By suspending these nanotubes above silicon chips, C12 maximally isolates qubits from environmental perturbations, achieving coherence times two orders of magnitude larger than previously measured in carbon-based quantum circuits. Integrating Plaquette into C12’s R&D workflow provides the quantitative foundation to evaluate how realistic hardware imperfections impact logical qubit performance across different error correction codes, including the high-rate quantum low-density parity-check codes (QLDPC) that are compatible with C12’s high-connectivity architecture.
As C12’s hardware architecture evolves, different system configurations might require distinct error-correction strategies. Plaquette enables the comparison of distinct error correction strategies, allowing to identify the best solution for C12’s scalable quantum processors.
Pierre Desjardins, co-founder and CEO of C12, said:
As we scale our carbon nanotube quantum architecture, rigorous fault-tolerance analysis has become essential to our roadmap. Plaquette enables our team to quantitatively evaluate QLDPC codes and other error-correction strategies under realistic conditions, including the unique noise characteristics and hardware-specific parameters. This partnership with QC Design accelerates our path to demonstrating logical qubits and building towards universal fault tolerant quantum computing.
Dr. Ish Dhand, co-founder and CEO of QC Design, said:
We’re excited to partner with C12 as they pioneer one of the most innovative approaches in quantum computing. Carbon nanotubes offer exceptional material purity and coherence properties that position C12 uniquely for scalable fault tolerance. Their high-connectivity architecture is particularly well suited for advanced quantum error-correcting codes, and we’re proud to support their team as they translate record-breaking physics results into practical quantum computing systems.
About C12
C12 is a Paris-based quantum computing company building the next generation of scalable quantum computers. The company pioneers a unique approach rooted in advanced materials science and innovative interconnect architectures, leveraging ultra-pure carbon nanotube spin qubits. Backed by more than €25 million in equity funding, C12 brings together an international team of over 60 employees, including leading quantum scientists. Through industrial partnerships and continuous technological innovation, C12 is laying the foundations for scalable, fault-tolerant universal quantum computing.
About QC Design
QC Design builds Plaquette, a design-automation platform for fault-tolerant quantum computing. Plaquette lets hardware teams simulate, analyze, and optimize architectures under realistic conditions, modeling 20+ hardware imperfections, well beyond typical open source tools, and providing libraries of QEC codes and decoders. With deep expertise in fault-tolerance strategies and a suite of advanced tools, QC Design enables quantum hardware teams to design scalable quantum computers faster and at an order of magnitude lower cost than building and maintaining similar software in-house.
