In the project entitled "Rydberg-atom physics in ponderomotive traps and atomic imaging devices" optical-lattice dipole traps for Rydberg atoms are developed, improved and applied in research. These optical traps have trap-induced level shifts that are much smaller than those in static-field traps. They are therefore well suited for high-precision spectroscopy and quantum information processing applications that are currently of high interest. The lattices exhibit a rich variety of adiabatic trapping potentials, which are studied via laser spectroscopy. The effect of lattice-induced photo-ionization on the trapped Rydberg atoms is measured. A spectroscopic method is developed that is based on microwave modulation of the optical-lattice beams. The method allows the research team to drive high-order multipole transitions without the application of large fields, which would cause level shifts, and with high spatial resolution. The research team develops three-dimensional optical lattices for microwave spectroscopy of optically trapped circular-state Rydberg atoms. The work has the prospect of yielding a high-precision measurement of the Rydberg constant.
In the second component of the work, a tip imaging probe (TIP) is employed to perform spatial-domain measurements of correlations in many-body Rydberg systems. In these systems, several de-localized Rydberg excitations are coherently shared between a large number of cold atoms in a highly entangled quantum state. The TIP system reads out the positions of individual Rydberg excitations in the sample via ion imaging. New measurements with the TIP setup allow the researchers to separate blockade-induced effects and effects due to Coulomb ion repulsion in the measured signals. The TIP experiment is applied to prepare and detect Rydberg atom crystals excited by adiabatic passage in randomly distributed samples of ground-state atoms.
Trapping individual atoms continues to be a major theme in atomic, molecular and optical physics. In a so-called "optical lattice," several intersecting laser beams are used to form a periodic grid of trap sites to trap atoms. An optical lattice is much like an egg carton holding eggs at periodic locations (where an egg is the atom's analogue). In this project a Michigan research team develops such optical lattices for Rydberg atoms. A Rydberg atom is a giant atom with one very loosely bound electron that travels, on average, quite far away from the atom's center. The research community believes that, in the long term, Rydberg atoms in laser traps can be helpful in the development of powerful quantum computers, which can treat mathematical problems that ordinary computers cannot solve. The optical Rydberg atom traps the Michigan team develops also have the potential of yielding information on fundamental constants, such as the Rydberg constant. Measurements of such constants are of great value because they serve as tests of our current understanding of the composition of matter and the inner workings of nature. In the project, graduate and undergraduate students are trained in research, research presentation, and in peer instruction. The project as a whole has a broader impact on society in that students at all levels become prepared to assume important tasks in science, industry and education. The project is accompanied by outreach components that aim to encourage high-school students to consider careers in science or engineering, such as the Michigan Physics Olympiad.
