Coherent Control of Nuclei and X-Rays

The possibility of mutual control of nuclei and photons offered by the emerging field of nuclear quantum optics is theoretically investigated in three different applications. This extension of quantum optics towards nuclei is motivated by modern X-ray Free Electron Lasers (XFEL) which open the possibility to coherently control nuclear states. As a first application we investigate the coherent population transfer between nuclear states in a three-level system driven by an XFEL. Such a level scheme is relevant for the triggering of isomers and might play a role for future energy storage solutions. The other way around, nuclei offer a platform to control single x-ray photons, which can be focused on spots essentially smaller than a single atom and used in future photonic circuits. The second part of this thesis puts forward a nuclear forward scattering setup that allows coherent control of a single x-ray photon using $^{57}$Fe nuclei. Finally, we show that nuclear quantum optics provides a significant improvement for detection in nuclear physics. The low-lying isomeric transition of $^{229}$Th can be addressed by VUV lasers and provides a potential next generation frequency standard. A main impediment is the large uncertainty of the nuclear transition frequency. Using an electromagnetically modified nuclear forward scattering setup, we show that coherence effects can reduce this uncertainty down to an unprecedented level