Quantum register

The first step in the computational process is to set up the quantum register, that is to define the positions where we want the atoms to be captured. In the physical device, the Rubidium atoms are suspended on a vertical plane, therefore planar geometric structures can be envisioned for the placement of our qubits. Their position can be adjusted up to a nanometer precision. With optical tweezers having a diameter of around 1 micrometer, a certain minimal distance between positions needs to be respected.

Creating the quantum register through the free placement of the atoms. A single atom trapped in an optical tweezer corresponds to a physical qubit.

Depending on the problem you want to solve, you can either define your register:

• from a preset pattern (grid, circular, triangular), as starting point, or later using the ‘multiple +’ icon

The pattern generator, used to ease the creation of typical atom configurations.

• by adding atoms one-by-one, using the ’+’ icon on the top right

In any case, you can easily move individual atoms or group selections of atoms at any moment using drag-n-drop.

Note for advanced users

Since positioning the qubits is part of the implementation, careful attention needs to be paid to this segment. It is important to keep in mind that due to the hyper-excited Rydberg state, the range of the interactivity of the atoms is extended up to a 70 principal quantum number, allowing for an influence range in the order of magnitude of tens of micrometers. Despite the increased hyper-excited influence zone, due to the so-called Rydberg blockade effect, entanglement is only possible up to 10-15 micrometers. This still makes non-neighboring atomic entanglement possible, hence the huge potential of flexible qubit arrangements.

For a simulation the loading is instantaneous, however when manipulating the real device, it is important to keep in mind that loading the quantum register is the most time-consuming section of an experiment. Due to the necessity of a potential rearrangement, since optical tweezers can guarantee to capture atoms approximately 50% of the time, creating the quantum register usually takes around 200ms with above 99% success rate.