Optical Lattice Engineering for Enhanced Interferometry and Sensing with Yb Atoms

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General audience abstract:This award supports a project to sensitively measure the interaction between light and matter. The experiments will be performed on an atomic gas cooled to very low temperatures in the laboratory, at which point it transforms into an exotic state called a Bose-Einstein condensate (BEC). Like a laser beam, the BEC can be split into multiple parts and then recombined. If the different parts interact differently with light, then this shows up in the properties of the recombined BEC. The splitting and recombination will be carried out with a particular type of light pulses called standing waves, which the research team will specially prepare to enhance the measurement sensitivity. By using light pulses to split, recombine, and then observe BECs, the team will precisely measure the strength of the light-matter interaction. The results will provide information regarding possible refinements of the underlying theory of this fundamental process. The atom being used - Ytterbium - has potential applications in the development of improved time standards for the global positioning system (GPS) and in the development of quantum computers; both of these efforts involve the sorts of laser-atom control techniques that this project will help to advance. The students working on this project will gain experience in experimental methods involving atoms, lasers, and electronics, and also be involved in data analysis, modeling, and connecting experimental results with theory. This will be good preparation for them to join the work force in academia and industry as part of the next generation of scientists and engineers. Technical audience abstract:The research team will develop techniques based on coherent atom manipulation in optical standing waves to improve the precision of atom interferometric sensors. In particular, the kinetic energy of an atom recoiling due to absorption of a single photon will be precisely measured as a frequency, by further development of the team’s previously demonstrated contrast interferometry technique with Yb BECs. This recoil frequency, combined with other measurements, will accurately determine the fine structure constant alpha, and test the theory of quantum electrodynamics (QED). The fine structure constant is ubiquitous in nature and QED theory extends across various physics sub-fields. The contrast interferometer utilizes pulsed optical standing waves to split, manipulate, and recombine BECs. The interferometer signal is obtained by monitoring the contrast of the resultant interference pattern via reflection of an optical traveling wave. The techniques that will be developed to enhance measurement precision will be broadly applicable to a large class of atom interferometric sensors including the acceleration due to gravity and its gradient. Together with these fundamental goals, this project will also advance BEC preparation, manipulation, and probing methods.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.