Towards deterministic preparation of single Rydberg atoms and applications to quantum information processing.
Circular Rydberg atoms and superconducting cavities are remarkable tools for the exploration of basic quantum phenomena and of quantum information processing. The aim of this work is to realize a deterministic source of individual Rydberg atoms. This source, producing atomic qubits on demand, is an essential tool for quantum information experiments in microwave cavity quantum electrodynamics. We plan to use the dipole blockade mechanism in a dense and small sample of ground state Rubidium atoms magnetically trapped in a superconducting atom-chip at 4K. In a simple model, the energy of two atoms in the same Rydberg state is a function of their distance. By tuning the excitation laser at the frequency of the isolated atomic transition, we expect to excite at most one atom within a blockade volume of ~ (5 µm)^3. By controlling the shape of the ultracold cloud and tailoring the excitation laser pulses, we expect to control the final number of Rydberg atoms within the cloud in a deterministic way. We are also exploring the use of the narrow millimeter-wave transitions between Rydberg levels to achieve atom-number selectivity. In parallel with the experimental work, we explore theoretically the possibilities opened by this deterministic source.