We deal with precision spectroscopy of trapped and laser-cooled atomic and molecular ions. For this purpose, we develop novel technologies for the coherent manipulation of individual ions and their spectroscopy.
To support our team, we are looking for 3 candidates for a PhD degree to join us in the three different projects described below. The salary will be paid in accordance with remuneration group 13 TVöD Bund (85%).

Quantum logic spectroscopy of molecular ions
Molecules with their rich internal level structure offer a fascinating field of research in the areas of precision spectroscopy, quantum chemistry and tests of fundamental theories. An important aim of these and of other applications is the full control over the internal and external degrees of freedom of the molecules. In this project, methods for the state preparation and spectroscopy of trapped molecule ions will be developed. For this purpose, a so-called logic ion is trapped together with the molecular ion in a Paul trap, which provides sympathetic and laser cooling to the molecular ion. By means of controlled coherent manipulation of the internal and external degrees of freedom of the molecule and of the logic ion with lasers, the internal states of the molecule can be prepared and investigated. Your task will be to implement these universal technologies at an existing apparatus by means of magnesium cooling ions and to demonstrate the spectroscopy on singly charged metal hydride ions.

Portable aluminium quantum logic clock
Aluminium ions have a forbidden transition which – due to its immunity to external disturbances – is particularly well-suited as a reference for an optical clock. However, due to the fact that aluminium does not have a suitable transition for laser cooling and detection, it is trapped together with a logic ion and sympathetically cooled by it. By means of a number of coherent laser pulses, the internal state of the aluminium ion can be transferred to the logic ion and be read out there. In this way, the currently most accurate clock in the world is operated at NIST (Boulder). In this project a portable aluminium quantum logic clock is set up and characterized using calcium as the logic ion. Your task will be to complement an existing apparatus by a new high-precision micro-structured ion trap and a miniaturized vacuum apparatus. The aim of this work is to carry out frequency comparisons with other clocks in Europe by means of this portable aluminium clock – side-by-side, but also over larger distances via an optical fibre connection. Through these comparisons, a frequency difference between the clocks can be related to their difference in position in the gravitational potential within the scope of the so-called "relativistic geodesy".

Quantum logic spectroscopy of highly charged ions
Selected highly charged ions have long-lived transitions in the optical spectral range, which are perfectly suited for optical clocks and the search for a variation of fundamental constants. In this project, an apparatus for the trapping and subsequent quantum logic spectroscopy of highly charged ions will be set up in cooperation with the MPIK in Heidelberg. A highly charged ion will be stored together with a beryllium cooling ion in a cryogenic Paul trap. Analogous to the aluminium clock, the internal state of the charged ions can be prepared and read out via a sequence of laser pulses. Your task will be to set up the required laser systems and the apparatus. The aim of this work is to demonstrate the first precision laser spectroscopy of charged ions.

Your profile:
Candidates should have successfully completed their graduation (Master's degree) in physics or a related subject. Experience in the field of experimental quantum optics or atom optics, UHV technology, laser cooling, atom traps, laser spectroscopy or electronics would be advantageous but is not a requirement. You will be able to realize exciting projects within a young and motivated team. We expect you to be creative, willing to learn and to communicate. You should be able to take responsibility for your project and integrate well into a team.
The graduation will take place at Leibniz Universität Hannover.