C12 is transitioning from a phase of scientific discovery and proof-of-concept demonstrations to one of systematic scaling. This means our focus is shifting towards automation, reproducibility, and process maturity, without sacrificing the scientific rigor and curiosity that got us here.
It is a demanding and exciting moment: we are still making new science, while simultaneously building the infrastructure that will carry us to a quantum advantage demonstration.
The person joining this team will need to be both a rigorous scientist and a pragmatic builder!
Your role at C12 Quantum Electronics:
- Own the end-to-end signal budget of each cryogenic setup: noise temperature, insertion loss, crosstalk, dynamic range, photon number delivered to the device, calibration of TWPAs, magnetic field measurements.
- In collaboration with the quantum physicists, quantify the impact of noise sources on qubit coherence and operation fidelities, calibrate pulses to optimize qubit readout and gate fidelities, design and test new measurement protocols.
- Design the dashboard to monitor performance metrics of the qubits and setups. Monitor and systematically improve figures of merit, ensure homogeneous performance across the park. Provide structured, quantitative feedback to R&D teams (superconducting resonator design and fabrication, carbon nanotube growth and characterization).
- Drive setup upgrades and new installations from specification through commissioning and acceptance testing, including supplier selection and technical follow-up.
- Co-design specifications for the integration of the measurement chain, own the qualification and validation chain against agreed system requirements.
- Work closely with Engineering to derive system requirements into technical requirements for the measurement chain of the product, and to define the associated metrology, verification and validation methods.
- Write the documentation that turn your work into shared team capability.
- Train and support quantum physicists and engineers on the setups and the measurement protocols and maintain common standards accross setups.
You are responsible for the error budget of the quantum gates (measurement, monitoring, improvement). You are accountable for the cryogenic DC and microwave control and readout chains whose performance have to be understood perfectly to determine qubit limitations, replicated across multiple identical machines, eventually operating in a data center without a cryogenics expert on site.
Quantum Instrumentation and metrology:
Measurement chain robustness and readiness for scaling :
Transfer and team support:
About you:
- You are driven by the engineering and scientific challenge of building a quantum computer, and you want to contribute to a meaningful milestone in the field.
- You hold a PhD in experimental physics or metrology, you have at least two years of additional experience as post-doctoral researcher or in industry.
- We are deliberately open on the sub-field: Superconducting or semiconductor qubits, quantum sensing or communications, atomic or optical metrology, astronomy or particle physics instrumentation, and similar backgrounds are all welcome.
- You have a proven track record of building, characterizing, and optimizing complex experiments.
- You have a strong experience with RF experiments: pulse sequencing, phase noise, IQ up/down conversion) and dilution fridges (cryogenic wiring, thermalization, shielding, fault diagnosis.
- You have strong analytical skills and a solid understanding of statistical methods.
- You are rigorous and well organised.
- You write Python fluently and use it autonomously to control experiments, process data, and build reusable tools.
- You hold yourself to high scientific standards, and you know when a result is solid enough to act on.
- You communicate clearly in English, in writing and in conversation, across technical and non-technical audiences.
You'll thrive if...
- You love the combination of hands-on lab work and industrial challenges.
- You want to be part of a team making landmark contributions to quantum computing at a moment when the field is maturing fast.
- You are energized, not daunted, by a fast-paced environment with an ambitious roadmap and high expectations.
- You want to work in a genuinely collaborative culture, a 90-person team spanning resonator fabrication, nanotube engineering, software, and theory, all under one roof.
- You share our values: scientific excellence, integrity, curiosity, care, and a commitment to building something that matters.
- 66,000 euros - 78,000 euros yearly base salary
- Stock options for every employee (BSPCE/ESOP)
- Sponsored trip to conferences around the world
- A highly dynamic international team
- Swile meal vouchers
- Mental health support with moka.care
- Training budget/ Annual Learning & Development Allowance
- Sabbatical leave (after 2 years in the company)
- Vibrant office culture (two office spaces in the heart of Paris, team lunches, offsite events, Friday breakfasts..)
- You like hands-on work and technology
- You want to contribute to achieving landmark results in quantum computing, making a difference in the emerging quantum technologies
- You want to work within a team of 80+ people with various backgrounds in nanofabrication, quantum electronics, and carbon nanotube science to create a revolutionary quantum computing processor
- You want to thrive in an exceptional scientific environment with several industrial and academic partners
- You share our values (excellence, scientific integrity, diversity, curiosity, and care) and want to help us define our product-focused culture and ambition to accelerate
Skills Required
- PhD in experimental physics or metrology
- At least two years of postdoctoral research or industry experience after the PhD
- Proven experience building, characterizing, and optimizing complex experiments
- Strong experience with RF experiments, including pulse sequencing, phase noise, and IQ up/down conversion
- Strong experience with dilution refrigerators, including cryogenic wiring, thermalization, shielding, and fault diagnosis
- Strong analytical skills and understanding of statistical methods
- Fluent Python programming for experiment control, data processing, and reusable tool development
- Clear written and verbal English communication skills
What We Do
C12 is building reliable quantum computers. The company is a spin-off from ENS launched in January 2020 by twin brothers Matthieu and Pierre Desjardins to supercharge the development of the lab’s promising new quantum technology. Quantum computing has the potential to change our lives. But frequent errors limit the technology’s viability. We are tackling the fundamental issue: the nature of the hardware itself. We are tapping into the simplest material–carbon–to drive a technological breakthrough in the field. Unlike other quantum computers, we use carbon nanotubes as the fundamental building block of our processor. By combining the power of an ultra-pure material with an easy-to-manufacture semiconductor device, we are building a scalable platform for quantum computing. Our executive co-founders bring a unique combination of scientific excellence and business skills to the company. Our team is made up of the world’s most accomplished experts in quantum electronics and carbon nanotube science. Our scientific advisors are renowned scientists and pioneers in spin qubits: Dr. Takis Kontos, Dr. Matthieu Delbecq and Dr. Jérémie Viennot. In June 2021, C12 secured a $10 million seed round with funding from 360 Capital, Bpifrance (Digital Venture Fund), Airbus Ventures, BNP Paribas Développement, and Octave Klaba (OVHcloud), and additional grants from Bpifrance and the Ile-de-France Region. We are leading quantum’s next material breakthrough, and we are just getting started. Silicon enabled the emergence of classical computing – it’s time for carbon to do the same for quantum !
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