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

Abstract

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.Entangled states can also be created in a probabilistic manner: By performing a suitable partial measurement of the system's state, the probe measurement outcome indicates whether the system has been laser projected into the desired state or not by the measurement's backaction. Such probabilistic schemes can relax the stringent requirements on the suppression of dissipation in our cavity-QED system [1,2]. cavity In our experiment, we load a chosen number of doppler-cooled mirror 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 us to prepare, to manipulate and to read out the quantum state of each atom. Using the dip dipole trap as an optical conveyor belt, the atoms are transported into dipole trap the mode of a high-finesse optical cavity. The cavity consists of two dielectric mirrors with a distance of 160 rtm, a finesse of F 106 and mode volume of V=6 66104 ltm3. These parameters lead to a conveyo maximum theoretical single-atom cooperativity parameter of about belt 120. The resonance frequency of the cavity is stabilized to the caesium transition at 852 nm using a lock laser which is 16 nm cavity detuned. mirror By observing the transmission of a weak resonant probe laser we can detect the presence of a single atom coupled to the cavity mode and observe the dynamics of one or more strongly coupled atoms. Sudden changes of the transmitted intensity indicate jumps in the detector r position of the trapped atom. Cooling by the probe laser extends the observation time to more than one second. We analyze the magnitude Conceptual drawing of trapped atoms and the stability of the atom-cavity coupling obtained in the being transported from a magneto-optical experiment for one and more atoms. Our goal is to perfectly control trap (MOT) into an optical cavity. the interaction of two or more atoms with the cavity field. Finally we discuss the possibility of implementing probabilistic entanglement schemes.[1] A. S. S0rensen and K. M0lmer, Measurement Induced Entanglement and Quantum Computation with Atoms in Optical Cavities, Phys. Rev. Lett. 91, 097905 (2003) [2] J. Metz, M. Trupke, and A. Beige, Robust Entanglement through Macroscopic Quantum Jumps, Phys. Rev. Lett. 97, 040503 (2006)