Schumm, Thorsten

Thursday Nov 21, 2013
Time: 13:00
Place: HPF G6
Hosts Tobias Donner / Tilman Esslinger 

Towards a "solid-state optical nuclear clock"

Thorsten Schumm
Vienna University of Technology, Austria

The radio isotope 229Thorium shows a remarkable and unique property: it possesses an extremely low-energy excited (isomer) state of the nucleus which is expected around 7.8 eV. It might hence be possible to directly excite the atomic nucleus with UV (laser) radiation, creating a bridge between atomic and nuclear physics. The (expected) narrow line width of the transition makes it a promising candidate for a new frequency standard. The excellent shielding of the nuclear transition by the electron shell allows to implant (dope) 229Thorium into UV transparent crystals and hence the realization of a solid state “nuclear atomic clock”.

In this presentation we will review the quest for the low-energy transition and discuss experimental approaches towards a new “nuclear” frequency standard. We will focus on interactions of the nuclear transition with the surrounding solid-state crystal fields and estimate line shifts and broadenings. As commonly used Rabi or Ramsey schemes cannot be used here, we propose a stabilization scheme based on fluorescence spectroscopy. We demonstrate, that for optimized operation parameters, this method might reach a fractional instability level of 10-19 . The current status and experimental progress will be discussed.