Final Report Summary - QLEDS (Quantum Logic Enabled test of Discrete Symmetries)
This proposal aims to apply ion-trap quantum logic techniques to precision measurements on individual (anti-)protons for fundamental physics tests. In particular, we consider g-factors of single (anti-)protons as a precise test of CPT symmetry. This requires a method to detect single (anti-)proton spin flips. Current efforts based on “magnetic bottle” techniques are highly successful, but also hurt by the extreme difficulty and slowness of the spin state detection. To introduce laser cooling and quantum logic spectroscopy for g-factor measurements, we have built a new cryogenic 5 T Penning trap setup based on the BASE-CERN Penning trap. We have demonstrated ablation loading of 9Be+ ions, shown laser cooling and sideband mode-coupling. A new femtosecond-laser based UV frequency comb has been developed. The system features an efficient spectral compression technique to allow motional sideband transitions and quantum logic spectroscopy on 9Be+ ions in the presence of the high magnetic field of the Penning trap. We have developed a new microfabrication process that allows the realization of cylindrically symmetric microstructures Penning traps to allow a single (anti-)proton to be Coulomb coupled to a 9Be+ ion for sympathetic cooling and quantum logic inspired state readout. In order to implement quantum logic spectroscopy for g-factor measurements on single (anti-)protons, the spin state of the particle must be mapped to its motional degrees of freedom for transfer to the logic ion. Towards this end, we have studied the implementation of essential laser-less quantum logic swap gates in Penning traps, supported by a static magnetic field gradient.