Academic Research

Context: The most advanced optical quantum clocks based on trapped ions are attaining a relative frequency accuracy of 10-18 and thus facilitate sensitive tests of fundamental theories of physics and searches for new unknown physics. Deviations from known physics (like the Standard Model of particle physics) might show up as temporal or spatial variations of fundamental constants (for example the fine-structure constant or the electron-proton mass ratio), so a precise measurement of the transition frequencies in ions (and other particles) could point to temporal or spatial variations of these constants.

Activities in the group of Prof. Cigdem Issever at HU: The research group prepares the setup of a novel highly charged ion (HCI) clock that will utilize an HCI species with a high susceptibility to possible variations of the fine-structure constant. The generated HCI is stored in a linear Paul trap and cooled and interrogated with the help of lasers and suitable control schemes (like quantum logic spectroscopy). Any time dependence of the frequency of the HCI’s clock transition is probed by a comparison with remote clocks for which no (or a different) variation of the fine-structure constant is expected.

Experimental setup for the internship project:

While the HCI clock is still in a preparatory phase, aspects of the time-dependent comparison of the frequencies of spatially separated clocks are already exercised with an existing laboratory setup. This setup will be used for the internship project; it has been built by two PhD students and comprises an optical table with a clock transfer laser (at 1550 nm), which is sent through optical fibers (non-polarization maintaining single-mode fiber) with a length of 0.1 km to a few kms. A fully fiber-based interferometric correction scheme (Michelson type) is applied to suppress phase noise generated on the fiber; in this way, the transfer of the laser signal through the fiber is stabilized and allows an accurate comparison of clocks connected by such (or even longer) fibers.

Scope of the internship project: The internship will consist of two phases. In the first few weeks, the intern will become acquainted with the scope and the aims of the HCI clock project.
Activities will comprise reading relevant literature and optionally experimenting with an existing Paul trap; this particular Paul trap exists at the Physics Department and is available for the education of Bachelor students. In the second phase, the intern will work on improving the experimental setup described earlier. This experimental work will aid in the automation of the acquisition of test data using ARTIQ (see https://mlabs.hk/experiment-control/artiq/). The intern will also have the chance to analyse and understand the recorded test data.

Advanced undergraduate students (from third year) 
Master's students 
Ph.D. students 

Scientific Literature Review