However, anyone wishing to calculate with atoms must be able to place them exactly. 'All the atoms on the conveyor belt have to have the same distance from each other,' is how Arno Rauschenbeutel sketches the challenge. 'Only then can we get them to interact in a controlled way in what is called a quantum gate.' By lining up gate operations like these it would already be possible to carry out simple quantum calculations.
The next aim of the Bonn physicists is to construct a quantum gate. For this purpose they want to 'write' quantum information onto two caesium atoms and then place them between two tiny mirrors. The intention is that they should interact there with each other, i.e. exchange information by emitting and absorbing fluorescent light. If this is successful, it will be the next milestone for the Bonn researchers on their way to the quantum computer.