  We present methods to manipulate and detect the motional state and the spin
state of a single antiproton or proton which are currently under development
within the BASE (Baryon Antibaryon Symmetry Experiment) collaboration. These
methods include sympathetic laser cooling of a single (anti-)proton using a
co-trapped atomic ion as well as quantum logic spectroscopy with the two
particles and could be implemented within the collaboration for state
preparation and state readout in the antiproton $g$-factor measurement
experiment at CERN. In our project, these techniques shall be applied using a
single $^9\text{Be}^+$ ion as the atomic ion in a Penning trap system at a
magnetic field of 5 T. As an intermediate step, a controlled interaction of two
beryllium ions in a double-well potential as well as sympathetic cooling of one
ion by the other shall be demonstrated.
