Host: Korsch

Title: Trapped-ion optical clocks: Telling time and testing physics at the quantum limit

Abstract: Optical transitions in trapped, laser-cooled ions can provide an extremely well-controlled frequency reference for atomic clocks.  The most stable and accurate atomic clocks now make measurements with total uncertainty approaching 1×10^-18.  The Ion Storage Group at NIST develops optical clocks based on the ¹S₀-³P₀ resonance in ²⁷Al⁺.  To perform precision spectroscopy on this atomic system we use the basic building block of a quantum computer, the two-qubit gate, which transfers information from ²⁷Al⁺ to a second ion species held in the same trap.  I will introduce these systems and present recent frequency comparisons between them and other optical clocks at NIST.   These comparisons provide valuable data for international time/frequency standards and can test our fundamental theories including relativity and the Standard Model.  I will also describe quantum metrology techniques that have allowed us to approach the quantum limit for stability in a ²⁷Al⁺ single-ion clock.