Nano-gratings and atom interferometry will be used to measure static dipole polarizabilities and van der Waals C3 coefficients for 15 species of atoms and molecules. The polarizability measurements will be used to test atomic structure calculations and to improve the accuracy of atomic clocks. The C3 measurements will test calculations of atom-surface interactions that include core electrons and realistic descriptions of surfaces.
The broader impacts of this work include a new course in atomic physics, support for student machine shop work, and training several new students to become leaders in basic and applied research. This research will foster collaborations with industry on optics, nanotechnology, and solar energy utilization.
Intellectual Merit: This project developed new applications for atom interferometry. Using nanogratings as beam splitters for atom waves, we developed new ways to measure atomic properties. In one example we applied an electric field gradient to an atom interferometer in order to measure the electric polarizability of Na, K and Rb atoms with unprecedented precision. In a second example, we studied atom diffraction from nanostructures in order to measure atom-surface interactions. By comparing results using Li, Na, K, and Rb atoms, we detected the contribution of atomic core electrons (not just valence electrons) to van der Waals forces. Another new application that we developed is a measurement of a wavelength of light that causes zero energy shift for atoms. This is known as a magic-zero wavelength. During this project we measured a magic-zero wavelength for potassium atoms of 768.971 nm, with less than 2 pm uncertainty. Broader Impact: Our measurements of static polarizabilities and magic-zero wavelengths can be used as benchmarks to test calculations of atomic dipole matrix elements. Related calculations can then be used with improved certainty to predict van der waals forces, lifetimes, dynamic polarizabilities, and collision cross sections. In the future, the techniques we demonstrated can be used with heavier atoms such as Sr, Cs, and Yb and this will be important for improving atomic clocks and interpreting parity non-conservation as a test of basic physics. Another broader impact of this project is training of graduate and undergraduate students. Six PhD students and six undergraduates worked on this project during this grant period.
