Senior Mechanical Engineer

IonQ, Inc. [NYSE: IONQ] is the world’s leading quantum platform and merchant supplier - delivering integrated quantum solutions across computing, networking, sensing, and security. IonQ’s newest generation of quantum computers, the IonQ Tempo, is the latest in a line of cutting‑edge systems that have been helping customers and partners including Amazon Web Services, and AstraZeneca achieve 20x performance results and accelerate innovation in drug discovery, materials science, financial modeling, logistics, cybersecurity, and defense.

In 2025, the company achieved 99.99% two‑qubit gate fidelity, setting a world record in quantum computing performance. Headquartered in College Park, Maryland, IonQ has operations in California, Colorado, Massachusetts, Tennessee, Washington, Italy, South Korea, Sweden, Switzerland, Canada, and the United Kingdom. Our quantum computing services are available through all major cloud providers, while we also meet the needs of networking and sensing customers across land, sea, air, and space.

IonQ is making quantum platforms more accessible and impactful than ever before.

We are seeking a Senior Mechanical Engineer to join our R&D team in Geneva. In this hands‑on role, you will design, validate, and continuously improve mechanical enclosures and subsystems that integrate optical and electronic components for our quantum products.

You will take ownership of mechanical solutions from early prototyping through to industrialized product release, with a strong focus on delivering compact, robust, and cost‑effective designs. Your work will ensure compliance with dimensional, thermal, and manufacturability requirements, including for highly demanding applications such as cryogenic systems.

You will be responsible for the mechanical development of cutting‑edge quantum systems, translating requirements into detailed designs and verified assemblies. This includes 3D modelling and documentation, engineering calculations and simulations, and hands‑on testing to validate thermal dissipation and mechanical performance. You will collaborate closely with optical, electronic, and system engineers to optimise interfaces and block specifications, and you will engage with external suppliers to prototype and manufacture parts efficiently.

As a senior contributor, you will help improve design practices, promote a rigorous engineering approach, and support multiple projects as a mechanical subject‑matter expert.

• Own mechanical design from prototype to industrialised product, including CAD documentation, assembly bring‑up, and validation testing
• Drive thermal management (heat sinking, conduction/convection, interfaces and materials), dimensional stability, and manufacturability through design, simulation, and optimization, working closely with cross‑functional teams and suppliers
• Perform thermal simulation to predict temperatures, gradients, and heat flows; correlate models with lab measurements and iterate designs and their optimization accordingly

We are looking for a candidate with a Bachelor’s or Master’s degree in Mechanical Engineering, Microtechnology, or equivalent, and at least five years of relevant experience in mechanical design and product development. You have hands‑on experience designing with sheet metal and/or machined parts, and a strong ability to develop thermal dissipation solutions for compact systems. Familiarity with cryogenic systems is an advantage.

You are rigorous, organised, and proactive, able to work independently while collaborating effectively in a multidisciplinary and Agile environment. Strong communication skills are essential, with fluency in English required;
French is considered a plus.

• Solid mechanical engineering foundation with proven experience delivering compact, industrial‑grade designs
• Structured, collaborative engineer with strong communication skills and a hands‑on approach to validation
• Knowledge of applicable norms and compliance requirements, including EMC and electrical/product safety aspects

You bring a track record of taking ownership of mechanical subsystems across…