Scalable entanglement of trapped ions

Summary form only given. Quantum entanglement is a fundamental element of schemes for quantum communication, cryptography, and computation. In a previous experiment, we demonstrated that two-particle entanglement could be generated in a deterministic way using trapped ions. However, that scheme also could not easily be applied to more particles in a single trap, because it relied on the particular behavior of two ions in a quadrupole RF trap. We have now demonstrated a truly scalable entanglement technique. The scheme is that of a recent proposal by Molmer and Sorensen. Twog /sup 9/Be/sub +/ ions are confined in a linear RF trap, and laser-cooled to near their motional ground state. Lasers are then used to drive Raman transitions between two ground-state hyperfine levels, which are separated by energy hw/sub o/.