Prof. Dr. Tanja Mehlstaubler: Multi-ion clocks and scalable ion trap platforms for ultracompact quantum sensors

Professor for Experimental Quantum Optics and Metrology

Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig

and Leibniz Uni-versity Hannover (LUH), Germany

Location: Elings Hall rm. 1601

Abstract: In 2012, we proposed multi-ion spectroscopy to improve the stability of optical ion clocks which is fundamentally limited by the quantum projection noise of the single ion. Multi-ion clocks will not only improve the stability by exploiting the higher signal to noise of multiple ions or their uncertainty by allowing for sympathetic cooling of clock ions using a separate ion species but will be the basis for future entangled clocks and cascaded clocks. For the multi-ion approach we have developed and qualified scalable high-precision ion traps, which are already in use in several experiments. A challenge is the high level of control of systematic shifts when scaling up a single trapped ion to a complex many-body system. I will discuss the state-of-the-art of precision spectroscopy in our clock setup which has been characterized in local and international clock comparisons. To exploit the full potential of multi-ion clocks and use them as geodetic sensors we have been working on scalable platforms. In recent projects, we are collaborating with German and European fabs, designing and testing nanophotonic systems for light delivery, light conditioning and trap integration. The integration of passive and active nanophotonic will be key to future robust and compact quantum sensors. It will allow us to scale down table-top optical experiments to PIC-sized optical platforms and create extremely robust systems that can be used outside the laboratory and in harsh environments.