Integration of the NVIDIA CUDA-Q Platform with Dynamiqs by Alice & Bob, Developing fault

Alice & Bob, a global leader in the race for fault-tolerant quantum computing, announced today at GTC Paris the ongoing integration of the NVIDIA CUDA-Q platform with Dynamiqs. This combination outperforms the most widely used libraries today, accelerating the simulation of complex quantum dynamics by up to 75x, on early benchmarks.

Alice & Bob has not yet built its first logical qubit, though the company is making significant progress toward this goal. Alice & Bob is a quantum computing startup focused on developing fault-tolerant quantum computers using a specialized type of superconducting qubit called a “cat qubit.” Cat qubits are designed to be inherently resistant to certain errors, particularly bit-flip errors, which simplifies the process of quantum error correction. The company’s research suggests that a logical qubit—defined as an error-corrected qubit that is more stable and reliable than a physical qubit—could be created using as few as five physical cat qubits.

Alice & Bob has achieved notable milestones, such as the tape-out of a 16-qubit quantum processing unit named Helium 1, which is intended as a prototype for an error-corrected logical qubit. Additionally, as of June 2025, the company is setting up a new laboratory to develop quantum chips, with a long-term goal of integrating 100 logical qubits by 2030

Startups That Have Built Logical Qubits

QuEra Computing: Demonstrated a logical quantum processor with up to 48 logical qubits in collaboration with academic partners.

Nord Quantique: Showed the operation of a single logical qubit capable of error identification.

CUDA-Q is NVIDIA’s open-source quantum development platform for hybrid quantum- classical supercomputing.

Dynamiqs is Alice & Bob’s high-performing quantum simulation libraries, open-source, it enables high-speed simulation of both open and closed quantum systems by leveraging GPU-accelerated computing. This allows researchers to dramatically speed up the simulation of time-dependent quantum systems that rapidly change and evolve, such as QPUs. Dynamiqs expands the size of systems that can be practically simulated, and performs parameter sweeps across a wide range of conditions in a fraction of the time previously required.

“Simulation is a critical step in the development of useful quantum processors, allowing us to understand how these complex quantum systems behave,” said Théau Peronnin, CEO of Alice & Bob. “Thanks to the integration with NVIDIA CUDA-Q, Dynamiqs can now run these simulations even faster, speeding up the development of our QPUs.”

Simulations of complex systems – such as quantum processors with multiple qubits and physical components – are computationally challenging. Modeling the rapidly changing dynamics, complex interactions and vast number of possible quantum states requires significant computational resources to determine how the output of a simulation can change based on changing inputs.

“With Dynamiqs, our goal was to make time-dependent quantum systems simulations faster, and from the beginning we decided to fully run them on GPUs, a new approach in the field,” said Ronan Gautier, a member of the core Dynamiqs development team and a Theoretical Physicist at Alice & Bob.

Dynamiqs outperformed initial expectations with a remarkable 75x improvement in speed from early
benchmarks. The integration will continue over the next months with performance expected to further increase.

In addition to speed, Dynamiqs unlocks new capabilities for researchers, who can now use automatic differentiation to compute gradients of simulation outputs with respect to various input parameters. This tool is essential for paramount tasks like quantum optimal control, to guide the system toward the target state with high accuracy; parameter estimation, to infer unknown properties from data; and quantum state tomography, to reconstruct the quantum state from measurements.

“CUDA-Q’s GPU acceleration opens up new possibilities for fast, scalable, and intelligent quantum system design and analysis,” said Tim Costa, senior director Quantum and CUDA-X at NVIDIA. “By combining this with its other capabilities, Dynamiqs is helping provide researchers with access to the state of the art in accelerated computing that they need for practical breakthroughs in quantum research.”