Dipole Blockade and Quantum Information Processing in Mesoscopic Atomic Ensembles

We describe a technique for manipulating quantum information stored in collective states of mesoscopic ensembles. Quantum processing is accomplished by optical excitation into states with strong dipole-dipole interactions. The resulting ``dipole blockade'' can be used to inhibit transitions into all but singly excited collective states. This can be employed for a controlled generation of collective atomic spin states as well as non-classical photonic states and for scalable quantum logic gates. An example involving a cold Rydberg gas is analyzed

High-Frequency (> 100 GHz) and High-Speed (< 10 ps) Electronic Devices

Contains an introduction, reports on four research projects and a list of publications.Defense Advanced Research Projects Agency Contract MDA972-90-C-0021National Aeronautics and Space Administration Grant NAGW-4691National Aeronautics and Space Administration Grant 959705National Science Foundation Grant AST 94-23608National Science Foundation/MRSEC Grant DMR 94-00334MIT Lincoln Laboratory Advanced Concept Program Grant BX-5464U.S. Army Research Office Grant DAAH04-95-1-0610Hertz Foundation FellowshipU.S. Army - Office of Scientific Research Grant DAAH04-94-G-016