Single-Ion Clocks for Tests of Fundamental Physics and Applications in Quantum Technology

From long-term frequency comparisons of our two 171Yb+ single-ion optical frequency standards with a millihertz uncertainty we improve previous limits for violations of Local Lorentz Invariance by two orders of magnitude. In addition, recent improvement in the clock performance will be discussed and our contribution to the opticlock project that will be a robust, high-availability and easy-to-use optical clock, which can be operated outside of...