Trapped-ion Fock-state preparation by potential deformation

Abstract

We propose protocols to prepare highly excited energy eigenstates of a trapped ion in a harmonic trap which do not use laser pulses to induce transitions among internal levels. Instead the protocols rely on smoothly deforming the trapping potential between single and double wells. The speed of the changes is set to minimize nonadiabatic transitions by keeping the adiabaticity parameter constant. High fidelities are found for times more than two orders of magnitude smaller than with linear ramps of the control parameter. Deformation protocols are also devised to prepare superpositions to optimize interferometric sensitivity, combining the ground state and a highly excited state.