The application of quantum techniques to the spectroscopy of single trapped particles has enabled the determination of atomic properties at unprecedented levels of precision. “Quantum-logic spectroscopy” (QLS) has enabled the next generation of atomic clocks and new precision tests of fundamental physical theories^[1]. Thus, we wish to extend the scope of quantum techniques to spectroscopically probe the properties of single isolated molecular ions^[2]. We also intend to establish a quantum toolbox for the non-destructive interrogation of single molecules by coupling to a single atom. These developments will pave the way for molecular precision spectroscopic measurements to study, e.g., a possible time variation of particle masses^[3-5] with N₂⁺ which has been identified as a promising candidate system^[3]. We will report our recent progress towards these goals.

[1] P. O. Schmidt et. al., Science 309 (2005), 749.
[2] M. Germann et al., Nature Physics 10 (2014), 820.
[3] M. Kajita et. al., Phys. Rev. A 89 (2014), 032509.
[4] S. Willitsch, Int. Rev. Phys. Chem. 31 (2012), 175.
[5] S. Schiller et. al., Phys. Rev. Lett. 113 (2014), 023004.