David Hume, Chin-Wen Chou, Till P. Rosenband, David J. Wineland
We have investigated theoretically and experimentally a method for preparing Dicke states in trapped atomic ions. We consider a linear chain of N ion qubits that is prepared in a particular Fock state of motion, jmi. The m phonons are removed by applying a laser pulse globally to the N qubits, and converting the motional excitation to m flipped spins. The global nature of this pulse ensures the m °ipped spins are shared by all the target ions in a state that is a close approximation to the Dicke state jD(m)N i. We calculate numerically the ¯delity limits of the protocol and ¯nd smalldeviations from the ideal state for m = 1 and m = 2. We have demonstrated the basic features of this protocol by preparing the state jD(1)2 i in two 25Mg+ target ions trapped simultaneously with an 27Al+ ancillary ion.
Physical Review A (Atomic, Molecular and Optical Physics)