Observation and Control of Coherent Processes Involving Rydberg Atoms

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

This project will study the fundamental response of individual atoms to external stimuli, such as the presence of other atoms or very brief pulses of bright laser light. The experiments will use "Rydberg atoms" (those in which at least one of the negatively-charged electrons has much more energy than normal and moves in a large, slow orbit around the positively-charged nucleus). Because the electric forces between the nucleus and the distant electron are so weak in Rydberg atoms, they are very sensitive to their surroundings. This sensitivity will be exploited in the experiments, magnifying the atom's response to its environment and making it easier to change the electron's motion or manipulate the forces between atoms in controlled ways. Some of the experiments could have direct applications in quantum computing because Rydberg atoms might serve to store and process information. In other cases, the experiments will provide insights to problems involving more complex systems, for example energy transfer in light harvesting systems, or the use of very brief laser pulses to view electron motion in molecules over extremely short time intervals (the so-called "attosecond" regime, which is a million-trillion times smaller than 1 second). The experiments will utilize ultrafast and cold atom techniques, separately and in combination, exploiting intense ultrashort terahertz pulses and controlled interatomic couplings to manipulate electron dynamics and/or atom-atom correlations. These systems are rich with opportunities for exploring novel aspects of few- and many-body quantum mechanics at the interface between ultrafast/strong field physics and cold atom physics. The problems to be addressed represent real challenges as the spatial and temporal scales relevant to the dynamics span many orders of magnitude, from electronic motion within individual atoms to correlations involving multiple atoms. One set of experiments will seek to further characterize the novel ionization behavior of atoms exposed to intense, true single-cycle pulses. Another will attempt to use such pulses to induce both ionization and recombination, coherently shuttling bound electrons from atoms to their neighbors. A third line of experiments will utilize efficient laser excitation of atom pairs into, and out of, Rydberg states at prescribed interatomic distances, toggling strong repulsive interactions between atoms to manipulate the position correlation of cold atoms in a magneto optical trap. Possibilities for producing self-ordered arrays of atoms without an explicit external confinement potential will be pursued. Lastly, controlled dipole-dipole couplings between atoms will be used to entangle electronic wavepackets on neighboring atoms, resulting in the transfer of coherent electronic wavepacket motion from atoms to their neighbors, at distances of several microns. New insights obtained from the proposed experiments have the potential to impact several other scientific areas including condensed matter physics, chemical physics, quantum information, quantum control, and attosecond science.