Experimental demonstration of quantum state tomography and qubit-qubit interactions for rare-earth-ion based solid state qubits

摘要

We report on the implementation of quantum state tomography for an ensembleof Eu$^{3+}$ dopant ions in a \YSO crystal. The tomography was applied to aqubit based on one of the ion's optical transitions. The qubit was manipulatedusing optical pulses and measurements were made by observing the optical freeinduction in a phase sensitive manner. Fidelities of $>90$% for the combinedpreparation and measurement process were achieved. Interactions between theions due to the change in the ions' permanent electric dipole moment whenexcited optically were also measured. In light of these results, the ability todo multi-qubit quantum computation using this system is discussed.