Sympathetic Cooling of a Proton with Resonant Image Current Coupling

Abstract

This thesis is the realization of the long standing goal of sympathetically cooling single particles with image currents. Particles with no electronic structure such as the bare proton or antiproton, are not amenable to standard laser cooling and ma-nipulation techniques and until now have been cooled only by coupling to cryogenictank circuits. In measurements of the proton and antiprotong-factor however, theenergy splitting used to read out the particle’s spin state is larger than thermal en-ergy fluctuations and special techniques are required to perform the measurement.The technique developed here uses a cloud of laser cooled beryllium ions to sym-pathetically cool a single proton by coupling to, and cooling a mode of the tank circuit. The use of this circuit resonantly enhances the energy exchange between the trapped particles and allows the cooling ions to be separated from the particle of interest over arbitrary distances. This technique, is the first demonstration of sympathetic cooling of a proton and a macroscopic LC circuit to below 25% of the environment temperature.Sympathetically cooled protons and antiprotons with this method enable an improved g-factor measurement by increasing the duty cycle of the experiment. This will further our understanding of matter-antimatter asymmetry by constraining CPT odd new physics and enhancing sensitivity to even more exotic physics. More-over, the technique presented here has general applications in experiments with trapped charged particles, enabling coupling of a large number of ions, distributed in many separated trapping regions to a single cold resonator.