Controlled insertion of one and two atoms into a high-finesse optical cavity

Entangled quantum states have applications as a model system for strongly correlated many body states, as resource for quantum information processing and as a tool for enhanced precision measurements. Deterministic entanglement schemes create the desired state by transferring the system under the action of a carefully chosen Hamiltonian into an entangled state. The system must follow a unitary evolution, and uncontrolled parasitic interactions with the environment leading to spontaneous decay or partial measurements of the state have to be avoided. The paper present an experiment, on loading a chosen number of Doppler-cooled caesium atoms from a magneto-optical trap into a standing wave optical dipole trap. The positions of the individual atoms are then determined with sub-micrometer precision, enabling to prepare, to manipulate and to read out the quantum state of each atom. Using the dipole trap as an optical conveyor belt, the atoms are transported into the mode of a high-finesse optical cavity.