The research activities at the QUEST Quantum Logic Spectroscopy group revolve around fundamental questions: Are the constants of nature actually constant? How accurate are the predictions of physical theories? The variation of fundamental constants predicted by several theories would manifest itself in a shift of atomic and molecular energy levels. Therefore, these questions can be answered by precision measurements of the internal structure of trapped and laser-cooled ions. Quantum engineering techniques developed for quantum information processing allow probing of previously inaccessible atoms and molecules with unprecedented accuracy.
The picture shows a sketch of an ion trap illustrating the principle of quantum logic spectroscopy: a logic ion (blue) is used for cooling, state preparation and readout of the spectroscopy ion (red). Using this "quantum logic spectroscopy", a highly accurate optical clock based on a single aluminum ion is being developed. A comparison with other accurate clocks allows the detection of a variation of fundamental constants, deviations from Einstein’s theory of relativity, but also more practical applications, such as measurements of the gravitational potential of the earth (relativistic geodesy). In addition to these laboratory investigations, also astro-physical approaches are supported. Absorption spectra of interstellar clouds are compared with today’s precise quantum logic spectroscopy data to probe a possible variation of constants on cosmological time scales. These research results will aid in developing a refined theory and therefore an improved understanding of nature.
More detailed descriptions of our different research projects can be found here.
Nils Scharnhorst receives Ph. D. Congratulations!
A highly stable monolithic enhancement cavity for second harmonic generation in the ultraviolet S. Hannig, J. Mielke, J. A. Fenske, M. Misera, N. Beev, C. Ospelkaus, and P. O. Schmidt For more information see:...
An avalanche transistor-based nanosecond pulse generator with 25 MHz repetition rate Nikolai Beev, Jonas Keller, Tanja Mehlstäubler For more information see: Link to paper
Mariia finished her Masterthesis, entitled "Setup of a logic laser for Ca+" Congratulations!
The Al-Clock experiment developed two mechanical monolithic enhancement cavity designs for SHG in the VIS and UV. They are mechanical highly stable and gas tight. All degrees of freedom are adjustable using high precision...