Observation of long decoherence times in a quantum logic gate using trapped Ba137 ions

Summary form only given. Trapped ion quantum logic gates following the model of Cirac and Zoller have been constructed by the NIST and Innsbrueck groups using /sup 9/Be/sup +/ and /sup 40/Ca/sup +/ ions respectively. We are operating a new quantum logic gate using the /sup 137/Ba/sup +/ ion confined in a microscopic trap of 80 microns radius. Raman cooling to the ground state, with N < 1, is shown by the asymmetric sidebands shown. We have measured the decoherence time of a such a cooled phonon mode to be greater than 1 millisecond, which indicates that the anomalously fast decays seen by the NIST group is not dominant here.