Expert Quantum Physicist

Alice & Bob is developing the first universal, fault-tolerant quantum computer to solve the world’s hardest problems. The quantum computer we envision building is based on a new kind of superconducting qubit: the Schrödinger cat qubit 🐈‍⬛ . In comparison to other superconducting platforms, cat qubits have the astonishing ability to implement quantum error correction autonomously! We're a diverse team of 250+ brilliant minds from over 35 countries united by a single goal: to revolutionise computing with a practical fault-tolerant quantum machine. Are you ready to take on unprecedented challenges and contribute to revolutionising technology? Join us, and let's shape the future of quantum computing together! About the mission We're looking for an experienced physicist to own the numerical simulation strategy for our superconducting qubits — setting direction, defining what counts as a trustworthy result, and identifying where our methods need to improve. This is a broad-expertise role spanning quantum physics, microwave engineering, and numerical methods: you don't need to be the top expert in each, just fluent enough across all three to make sound calls and know when to bring in specialists. About the role As technical lead for numerical simulation of superconducting qubits, you'll own how Alice & Bob predicts and validates device behavior before it reaches the lab. You'll define our simulation approach — from microwave design to qubit dynamics — and set the bar for when a result can be trusted. Where our methods fall short, you'll spot it and drive the fix. You're not executing someone else's roadmap; you're setting it, working closely with the physicists and engineers in the details. About you You have several years of experience beyond your PhD, spanning quantum physics, microwave engineering, and numerical methods — not necessarily as the top expert in each, but with a strong enough command of all three to make defensible calls at their intersection. You're comfortable challenging a result that doesn't hold up, backed by rigor rather than instinct. You hold your own with deep specialists without deferring reflexively — and you're motivated by owning a technical direction, not just contributing to one. Responsibilities Own the predictive performance of our simulation stack end to end — accuracy, reliability, and efficiency from device physics through numerical implementation. Set the standard for what "trustworthy" means across microwave, quantum, and numerical simulations — defining accuracy, convergence, and validation practices, and leading the theoretical justification of our tools and methods. Find and fix what's holding the stack back , whether the bottleneck is performance, robustness, or model fidelity. Shape the roadmap for our simulation tools, working closely with domain experts across the company. Close the loop with experiment — validating simulations against measured device performance alongside experimentalists. Be the go-to authority on simulation methodology across the team. Requirements 7+ years of post-PhD experience in a relevant academic field or industry. PhD or equivalent in quantum physics, applied physics, electrical engineering, quantum information, or computational physics. A proven track record of technical leadership: driving simulation or modeling methodology at the organizational level, with results that directly shaped device design decisions. Broad, hands-on mastery across the full simulation chain — from device physics to numerical implementation — with recognized, go-to depth in at least one of these areas. Deep experience simulating superconducting qubits or comparable systems: finite element methods (Ansys HFSS, COMSOL, Palace), circuit quantization (scQubits, Quantum Metal), and quantum simulation (QuTiP, Dynamiqs, CUDA-Q). Command of the underlying quantum physics: circuit QED, Hamiltonian modeling, open quantum systems, decoherence mechanisms, physical gates and measurement. Fluency in microwave engineering for quantum applications: passive components (resonators, transmission lines, filters, couplers, circulators), active devices (amplifiers, mixers), and measurement instrumentation (VNAs, spectrum analyzers, homodyne/heterodyne detection). Strong software engineering foundations for scientific computing — Python, NumPy/SciPy or JAX, and Git — sufficient to build and maintain simulation infrastructure others rely on. The judgment to determine when a simulation result can be trusted, and the standing to make that judgment hold across teams — even against pushback from domain experts. A track record of mentoring senior scientists and engineers, and building consensus among specialists who don't naturally agree. Nice to have Hands-on experience with HPC or large-scale simulations. Publications in circuit QED or computational electromagnetics. Hands-on experience in experimental research, providing a practical sense of how quantum devices behave in the lab — beyond what models predict. Recruitment Process Screening Call with Grace, Talent Acquisition Specialist (30 min) Hiring Manager Interview with Mattis (45 min) Technical Presentation with the Team (60 min) Leadership Team Interview (45 min) Fit Interview (45 min) Reference check Benefits: - Our success is your success: own it with our BSPCE plan - Direct IP Compensation: Earn substantial bonuses for driving the core patents that define our quantum architecture. - Flexible remote policy, up to 40 % a month - A P arental plan including additional benefits such as crèche support or additional days-off to take care of under 12 years old children - Subsidized membership with Urban Sports Club - Mental health support with moka.care - 25-day vacation policy (as per French law) + RTT - Half of transportation cost coverage (as per French law), or yearly allowance for the die-hard bicycle users - Competitive health coverage, with Alan. - Meal vouchers with Swile, as well as access to a fully equipped and regularly stocked kitchen - French language courses covered by the company for those interested Research shows that women might feel hesitant to apply for this job if they don't match 100% of the job requirements listed. This list is a guide, and we'd love to receive your application even if you think you're only a partial match. We are looking to build teams that innovate, not just tick boxes on a job spec. You will join of one of the most innovative startups in France at an early stage, to be part of a passionate and friendly team on its mission to build the first universal quantum computer! We love to share and learn from one another, so you will be certain to innovate, develop new ideas, and have the space to grow.