In the first part of my talk, I will present results obtained in the group of Markus Oberthaler in Heidelberg. We observed the condensation of a spinor Bose gas in a box potential. Using local control, we probed the underlying dispersion relations of the emerging quasi-particles and experimentally found two Goldstone and one Higgs mode. We witnessed thermalization by comparing the measured power spectra of spin and density with a thermal prediction obtained in the Bogoliubov approximation. In the second part, I will introduce experiments which are currently performed in the group of Jörg Schmiedmayer in Vienna. Here, we use one-dimensional Bose gases in a magnetic double-well potential. We aim at implementing new weak measurement schemes by local and global outcoupling of few atoms. Further, I will present our recent progress developing a Hamiltonian learning framework for quantum fields.