ECAMP 15

The Neutral Atom KAT-1 Collaboration is working on the realisation of a full-stack quantum computing solution, with a quantum processing unit (QPU) based on neutral atoms with Rydberg interactions, trapped in optical tweezer arrays. Out of a total of three QPU setups: a first generation ⁸⁸Sr system in Amsterdam and the 2nd generation ⁸⁸Sr setup in Eindhoven, this work concerns the ⁸⁵Rb demonstrator system at Eindhoven University.
The relatively low complexity of Rb laser cooling combined with a robust Artiq control system, as well as intermittent scheduling of calibration routines and machine-learning based optimization runs, ensure that the setup can be operated remotely and is operational 24 hours per day.
The ⁸⁵Rb qubit is based on the |𝐹=2,𝑚_𝐹=0⟩→|𝐹=3,𝑚_𝐹=0⟩ clock transition, which is driven with 3 GHz microwaves, offering a robust single-qubit gate drive. Our coherence times are in the tens to hundreds of milliseconds range which, combined with a 0.1 MHz Rabi frequency, allows for long qubit control sequences. For the qubit driving we use a Quantum Machines Operator-X module, which enables us to implement complex pulse shapes on a fast timescale with excellent phase control, for robust pulses and optimal control applications. As a first demonstration we have implemented proof-of-principle experiments on theoretical qubit-drive noise models, which show excellent agreement with analytical results and simulations.
The qubit control toolbox will be completed with the addition of a Stark-shifting laser for single qubit addressing through local Z rotations and two-photon Rydberg excitation to the 60S level, which are both currently under development. The ⁸⁵Rb demonstrator system forms an ideal platform for collaboration with our theory department, which focuses on the development of neutral-atom-specific quantum algorithms and optimal control techniques. This serves as the first step in enabling third-party access to our QPUs via the Quantum Inspire platform.