Applied Physics Seminar

Abstract: Measurements unavoidably leaves traces on a quantum system. While in the past this measurement back action was considered to be detrimental to any quantum application it meanwhile became clear, that well-timed measurements of controlled strength, indeed can steer the dynamics of a system in a well-controlled way. It even can impose dissipation on the system to reach quantum states which are not accessible by conventional coherent control. I will present a case where quantum measurements induce quantum random walks on a spin system akin bosonic sampling [1], where measurement of different strength induce a phase transition [2] or where it cools a mechanical cantilever [3,4].

[1] D. D. Bhaktavatsala Rao, et al., arXiv:1804.07111
[2] M Pfender et al., arXiv:1806.02181
[3]D. D. Bhaktavatsala Rao, et al., Phys. Rev. Lett. 117, 077203 (2016)
[4]T. Oeckinghaus et al. in preparation

More about the Speaker: Prof. Dr. Joerg Wrachtrup is a professor at the 3rd Physical Institute of the University of Stuttgart. After training in physics in Berlin he worked as a post-doctoral scientist at the Technical University of Chemnitz between 1994 and 2000, before becoming Professor of Physics and Institute Director at the University of Stuttgart in 2000.

His group works on a wide range of imaging methods, focusing on the very small scale. These include nanoscale photonics, coherent Raman scattering microscopy, diamond magnetometry and single-molecule fluorescence biophysics.
Prof. Wrachtrup has received a number of awards and distinctions, including the 1996 Gustav-Hertz Prize of the German Physical Society, the 2005 Stepanov Award from the Belorussian Academy of Science, and the 2011 Gottfried Wilhelm Leibniz Prize. He has also been elected as a Max Planck Fellow at the MPI for Solid State Research in Stuttgart