Franck-Condon physics in a single trapped ion

We propose a way to explore the Franck–Condon (FC) physics using a single ion confined in a spin-dependent potential, formed by the combination of a Paul trap and a magnetic field gradient. A correlation between electronic and vibrational degrees of freedom, called electron–vibron coupling, is induced by a non-zero gradient. In the case of a sufficiently strong electron–vibron coupling, FC blockade of low-lying vibronic transitions takes place. We examine the feasibility of observing FC physics in a single trapped ion and demonstrate many potential applications of ionic FC physics in quantum state engineering and quantum information processing.