Applied Physics Seminar

Optical lattice clocks based on highly forbidden optical transitions in ensembles of ultracold neutral atoms have the potential to operate at the highest levels of stability due to the parallel interrogation of many atoms. As a direct consequence of the many-particle nature of these systems, understanding and controller interactions between atoms and the resulting density-dependent frequency shifts is crucial for maintaining high accuracy, even for systems utilizing fermionic atoms. Density-dependent shifts have been an important contributor to the 1.4 × 10−16 fractional frequency uncertainty of the fermionic 87Sr optical lattice clock at JILA, and we have recently reduced these shifts to the 10−17 level by changing the lattice geometry. Additionally, when viewed from a different perspective, lattice-trapped atoms represent an intellectually compelling many-body system, and this aspect has non-trivial consequences for high precision spectroscopy. In this talk, I will discuss these developments and present new spectroscopy results obtained with our next-generation sub-Hz laser.