Efficient Cat Qubit Simulation Intern M/F

PURPOSE OF THE ROLE

In a context where bit flips in cat qubits are exponentially rare, and where the Hilbert space grows quickly as soon as several modes are involved, estimating bit-flip probabilities in multi-mode operations lies beyond the reach of both brute-force simulation and exact master-equation methods.

The Research Intern - Efficient Cat Qubit Simulation addresses this gap by making such estimates computationally tractable, so that error rates of multi-qubit operations can be quantified and better understood.

Reporting to the Device Theorist, you will work closely with the Simulation Model team to explore how tensor-network representations, quantum trajectories and efficient simulation techniques can be combined to estimate bit-flip probabilities in many-mode settings, building on efficient simulation methods already developed for a single cat qubit.

Responsibilities:

1. Develop simulation methods for many-mode cat-qubit systems

• Combine tensor-network representations with quantum trajectory unravelings of the Lindblad master equation to simulate multi-mode operations
• Verify the numerical robustness of the simulations (Hilbert-space and bond-dimension truncation, solver stability and precision)

2. Develop efficient simulation strategies for many-mode bit flips

• Extend efficient simulation methods developed for a single cat qubit to multi-mode systems
• Extract statistically reliable estimates of bit-flip probabilities and rates from the simulated trajectories

3. Validate and benchmark the approach

• Compare estimates against exact references where they exist (master-equation results, single-qubit simulation results) and against theoretical predictions
• Quantify the computational cost and scaling of the method relative to standard Monte Carlo sampling

4. Interpret the physics of bit flips in multi-mode operations

• Analyse simulated bit-flip trajectories to characterise the underlying error mechanisms
• Identify and explain discrepancies between simulated behaviour and theoretical expectations

5. Document and communicate results

• Document methods, code and results for reuse by the Simulation Model team
• Present progress in regular team meetings and formulate recommendations for extending these simulation methods to further multi-qubit operations

Requirements:

You are a Master's or final-year engineering student with a strong background in quantum physics and numerical methods. You are motivated by research at the interface of theory and computation, and are able to drive a technical project with a high degree of independence while seeking feedback from more experienced colleagues.

• LANGUAGES: Proficient in English
• Good understanding of quantum mechanics and open quantum systems (density matrices, Lindblad master equations)
• Programming experience in Python or Julia for scientific computing
• Autonomy and comfort with open-ended research questions that have no guaranteed answer
• Clear technical communication and a collaborative attitude within a multidisciplinary team
• EXPERIENCE: No prior professional experience required

Nice to have:

• Familiarity with quantum trajectories and stochastic unraveling
• Exposure to tensor-network methods (e.g. matrix product states)
• Knowledge of Monte Carlo methods and statistical estimation
• Experience with Julia, numerical ODE/SDE solvers, or GPU-accelerated and high-performance computing
• Habit of rigorous numerical practice (convergence checks, truncation control, precision and solver choice)
• Experience reading and applying current research literature
• A previous research, project or internship in quantum physics or scientific computing is an asset