From Rydberg atom to quantum bit

In this research programme, physicists will make a lattice of Rydberg atoms for the first time. In Rydberg atoms the outermost electron is highly excited and is only weakly bound to the atom. Thanks to these electrons the interactions between Rydberg atoms are very strong and the atoms form a good basis for a quantum bit. These atoms can only be used in a quantum computer, however, if they are arranged next to each other in the clearly ordered manner.

The physicists will make these lattices of Rydberg atoms in two different ways. The first approach is to take a lattice of ground-state atoms and subsequently excite the atoms one by one with a laser into a Rydberg atom. The second approach is to shoot a laser at an ultracold gas of atoms. Although in the second case the atoms are randomly arranged, a neat row of Rydberg atoms is formed in the laser beam. As Rydberg atoms can be switched on and off with a laser, they can be carefully controlled as quantum bits. The lattices of Rydberg atoms can also be used to simulate lattices of quantum spins, important model systems for condensed matter. The advantage is that you can allow the Rydberg atoms to interact in a controlled manner.

Dr. Robert Spreeuw, programme leader: "Lattices of trapped atoms and Rydberg atoms are currently hot topics. Fantastic possibilities will arise by combining these two developments. This programme will make it possible to enter this new and highly promising line of research."

This programme is a collaboration between:
- University of Amsterdam: Dr. R.J.C. Spreeuw, Dr. N.J. van Druten and Prof.dr.ir. H.B. van Linden van den Heuvell;
- Eindhoven University of Technology: Dr. S.J.J.M.F. Kokkelmans, Prof.dr.ir. O.J. Luiten and Dr.ir. E.J.D. Vredenbregt.